INNOVATIVE SOLUTION IN ENGINEERING A Journal of the Nigerian Academy of Engineering A publication of the Nigerian Academy of Engineering

i ii

THE NIGERIAN ACADEMY OF ENGINEERING

Chemical Engineering Complex University of Lagos, Akoka,Yaba, Lagos P. M. B 1028, Akoka, Yaba, Lagos Telephone: +2348023192250, +2349070778171 Email: [email protected], Website: www.nae.org.ng

Officers and Council 2018

President Engr. (Mrs.) Joanna O. Maduka, FIET, FNSE, FAEng, MFR

Vice-President Engr. Prof. Fola Lasisi, FAEng, FNSE, FASCE, FNIAE, FNIM

Honorary Secretary Engr. Prof. A. O. Denloye, FAEng

Honorary Treasurer Engr. Prof. D. S. Matawal, FNSE, FAEEA, FAEng

Members of Council Engr. Titi Omo-Ettu Engr. E. O. Okeke, OON, CFR Engr. O. A. Ige, MFR Engr. I. K. Inuwa, OFR Engr. Dr. F. I. Amakiri Engr. Dr. F. E. Osaisai Engr. Olusegun Adedeji Engr. Dr. O. O. Phillips Engr. Prof. S. O. Adeyemi Engr. Prof. R. I. Salawu Engr. Prof. A. F. Ogunye

iii Copyright © Nigeiran Academy of Engineering

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ISSN: 2636-5197

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The Nigerian Academy of Engineering Chemical Engineering Complex University of Lagos, Akoka P.M.B 1028, Akoka, Yaba, Lagos, Nigeria e-mail: [email protected] website: www.nae.org.ng Tel: 09070778171

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iv TABLE OF CONTENT

Preface vi Acknowledgements vii Foreword viii

Financial Evaluation of Large-Scale Water Projects: A Case of Hydropower Development In Nigeria. O. D. Jimoh, M. Santini, R. Valentini and R.Cervigni 1

Innovations in Water and Environmental Infrastructures Agunwamba, Jonah Chukwuemeka 14

Reservoir Sedimentation Modelling and Prediction of Project Lifetime C. C. Mbajiorgu 29

Prediction of the Onset of Pain Threshold in Sickle Cell Disease E.E. Alagbe, C. Solebo2and A.A. Susu 43

The Thermodynamic System as a Metaphor for Engineering Education in Africa Adewumi, Michael and Obonyo, Esther 58

An Innovative Technique For Power Quality Assessment In Electric Utility Networks Frank N. Okafor, Osita U. Omeje, and Adeola O. Balogun 72

A Total Optimization of the Electical Power Value Chain: Challenges, Opportunities and Intervention Strategies Momoh, James A. 83

Hierarchical Bayesian Parameter Estimation of the Reliability of Nanoscale Metallic Oxide Semiconductor (MOS) Devices Wilkistar Otieno, O. Geoffrey Okogbaa 99

Innovations in HHO Gases Produced through Water Electrolysis E. C. Ugwuagbo 116

Guidelines for Authors 120

v PREFACE

The emergence of a journal published by the Nigerian Academy of Engineering (NAEng) and titled INNOVATIVE SOLUTIONS IN ENGINEERING (ISIE) is a welcome development. The aim is to document developments in engineering which are classify as sufficiently innovative in solving diverse practical problems in Agriculture, Electricity, Energy, Transportation, Water Management, Automation, Engineering Policy and Education and any other engineering field. The goal is to identify and publicize engineering solutions from which entrepreneurs can spring out to setup entities that create jobs to reduce the growing challenge of youth unemployment. The time to start is now.

NAEng is motivated in this effort by the quantum of very promising research projects carried out in Nigerian Universities and Research Institutions which end up on the shelves of libraries while citizens proudly import match sticks from abroad. ISIE is focused on creating entrepreneurs from abandoned and current innovative research outcomes by publicizing such outstanding results which can be deployed to solve diverse societal problems for the common good. This maiden edition of ISIE is a good start but definitely far from the vision of NAEng which seeks to engender entrepreneurial development through deliberate efforts at identifying, selecting and publicizing commercially sustainable research results. Ubiquitous possibilities exist in this area.

Furthermore, the pattern of response by authors to this maiden edition exhibits a very encouraging trend. Of the eight papers selected for publication, four are either wholly from the diaspora or in collaboration with a home-based researcher.

The four papers discussed innovative techniques in resolving challenges in engineering education, Parameter Estimation, Financial Evaluation of Large Water Projects as well as application of optimization to Electricity Market Operations and Power Systems Control. In the same vein, the first of the four papers from the home-based authors present Trending Techniques in Reservoir Sedimentation Modelling and Prediction of Project Lifetime while the second examined Innovations in Water and Environmental Infrastructures for modern living. The third paper on Power Quality aims at resolving the emerging controversy in the perfection of future GENCO-DISCO contracts regarding the right specification for the “commodity” power while the fourth paper attempts to structure the chaos surrounding the therapy and management of one of the most devastating natural sicknesses plaguing Africa- Sickle Cell Anemia. Many of the papers submitted for publication contain sufficiently new information but are insufficiently researched.

The only letter to the editor discusses Hydrogen - Hydrogen - Oxygen (HHO) technology which is currently trending the world over. Its application appears more relevant to Nigeria than most other climes. This contribution is the nearest to commercial implementation with prototype designs shown and a few functional tests conducted.

The final goal is to institute an annual discourse (colloquium or conference) from which delivered and discussed papers will be selected to make the journal. The identified papers and their results will also form the nucleus of government engagement by the Academy.

vi ACKNOWLEDGEMENTS

I want to acknowledge gratefully the financial support of the Ministry of Science and Technology under the watch of Dr. Ogbonnaya Onu. I also thank the members of the editorial committee led by Prof. Frank. N. Okafor as well as congratulate the authors whose papers scaled the referee process. On behalf of the members of NAEng, I thank you all.

Engr. (Mrs.) Joanna Olu Maduka, FIET, FNSE, FAEng, MFR President, Nigerian Academy of Engineering

vii FOREWORD

You are welcome to this maiden edition of the journal of the Nigerian Academy of Engineering (NAEng) titled “Innovative Solutions in Engineering”- (ISIE)

The aim of this Journal is to publish innovations in fields of Engineering such as Electrical, Mechanical, Industrial, Civil, Biomedical and Agricultural Engineering as well as Engineering Policies and Education authored by seasoned professionals in the various disciplines.

In this maiden issue, several Papers have been painstakingly selected for publication by the Editorial Board after a careful review process.

Highlights of some of the papers published are stated below to wet the reader’s appetite for this epoch making edition. In selecting the papers to be published, the Editorial Board appears to have been guided by the existential challenges in Nigeria. Hence, the first three papers focus on Water Resources Engineering while others deal with Electricity/Energy and Biomedical Engineering in that order.

In one of the papers on Water and Environmental infrastructure, the author highlighted the general barriers to innovation in this field to include lack of basic infrastructure, deficit taught pattern and misconception. Examples were given and solutions to the highlighted challenges were proffered.

Financial Evaluation of Large Scale Water Projects was also discussed in another paper where the writer noted the inappropriate distribution of water resources and increasing gap between demand and supply. The Unit Reference Value (URV) technique was adopted for assessing economical options for developing hydro power plants to provide power and bridge the gap between demand and supply of water. Various climatic conditions were taken into consideration in the discussions by this paper.

A very interesting treatise on Reservoir Sedimentation Modelling and Prediction of Project Lifetime could be the reader’s delight as the author presented the Generalized Sediment Transport Model for Alluvial River Simulation Version 3 (GSTARS3). The GSTARS3 can be used to predict sedimentation processes in reservoirs and therefore estimate reservoir projects lifetime. Methods for sediments removal were also briefly reviewed in this paper.

We cannot talk about Innovations in Engineering without taking a deep delve into Electricity and Power Engineering especially in a clime like ours. The journal presents three papers in this field written by seasoned and highly experienced Professors and industry based Engineers.

The emerging Regulatory Framework by NERC has imposed the status of “commodity” on electricity which must possess measurable quantity to worth its price. Hence, the first paper addressed power quality and its assessment where the writers proposed the “S-Flow” method as an improved model for identifying and then assessing contributors to poor power quality at points of common coupling (PCC) in an electric network.

viii The second paper presents improvements in the physics of semiconductors for electronic components using the Hirarchical Baysesian Parameter Estimation of the Reliability of Nanoscale Metallic Oxide Semiconductor Devices.

The third in this group looks at Total Optimization of the Electrical Power sector value chain. The writer focused on the Nigerian Power industry starting from the Generating companies through the Transmission and Distribution companies and down to the Customers. This paper is very appropriate for our country Nigeria that is currently bedeviled with dwindling Electricity market and unreliable power supply.

Crisis period have been a major challenge for Sickle Cell patients globally. In a paper titled Prediction of the onset of Pain Threshold in Sickle Cell Disease, the writers presented their model developed to facilitate the prediction of the onset of pain threshold thereby aiding the search for a threshold pain alert system for sickle cell patients. This innovation is very timely considering the trauma both the patients and their attendants pass through each time there is a sudden crisis.

Finally, this edition of NAEng journal did not leave out a paper that criticizes and then recommends ways of transformation of Engineering Education in Sub-Sharan Africa. This was put together as a Thermodynamic Framework for Engineering Education in Africa by eminently qualified teachers of engineering; sharing their experiences over the years.

In a short paper under the section “Letters to the Editor”, a young and upcoming Engineer discussed the status of Hydrogen-Hydrogen-Oxygen (HHO) technology in Nigeria. By implementing a unique design for water electrolysis, hydrogen on demand is produced which is injected into fossil fuel to achieve up to forty percent increase in the Specific Energy Content (SEC) of the fuel. Thus improved combustion efficiency is obtained which drastically reduces the green gas content of the exhaust gases.

I appreciate all those who submitted papers for this journal especially those whose papers were published. I also congratulate the editorial board and indeed all members of the Nigerian Academy of Engineering for this historic journal.

“Innovative Solutions in Engineering” is hereby recommended to be read by all Engineers and indeed all lovers of Innovations as we all look forward with high expectations to subsequent editions.

ix A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Financial Evaluation of large-scale water projects: a case of hydropower development in Nigeria

1O. D. Jimoh, 2M. Santini, 3R. Valentini and 4R. Cervigni 1Department of Civil Engineering, Federal University of Technology, Minna, Nigeria. 2Division of Climate Change Impacts on Agriculture, Forests and Ecosystem Services (IAFES), Foundation Euro-Mediterranean Center on Climate Change (CMCC), Lecce, Italy 3The World Bank Group, Washington [email protected] [email protected]

ABSTRACT Nigeria is a land with unevenly distributed resources and huge climatic differences. Basic conditions are distorted through the fact that access to these available resources was not guaranteed to all in the past. Increasing population and associated economic growth, together with changing climate, put pressure on water resources. Existing gap between demand and supply in the power and agricultural sectors is widening. Increasing existing capacity of infrastructures in the sectors implies the construction of capital projects with associated high cost. The government and investors need informed decisions in evaluating alternatives. The scheme involves development of Zungeru hydropower (the dam at elevation +230m) downstream of Shiroro to utilize water released from Shiroro reservoir. The choice is whether to increase the dam height to increase capacity for power production or develop an interbasin water transfer scheme (Gurara II dam and water transfer to Shiroro reservoir). The decision is further constrained by climate variability and climate change in the basin. The Unit Reference Value (URV) technique was adopted in assessing the economically feasible option in developing hydropower scheme in Nigeria. Runoff simulations by four climate models were considered as input into the financial evaluation at 10% discount rate. The URV for interbasin scheme is 139.32 US cent/KWh (N515/KWh) for the worst climate model and 16.76 US cent/KWh (N62/KWh) for the best climate model. Under the increasing dam height, the worst climate model has a URV of 210.04 US cent/KWh (N777/KWh) and 40.36 US cent/KWh (N149/KWh) for best climate model. The URV for interbasin transfer option is lower than that of increasing Zungeru dam height. The relative increase in URV for increase dam height over interbasin transfer varies from 125% to 242% for discount rate 10%. Thus, increasing dam height is not a suitable option under an active or inactive government policy. The conclusions of the paper do not entail endorsement by the World Bank or its Board of Directors.

Keywords: water stress, financial analysis, unit reference value

INTRODUCTION east to about 500 mm in the extreme north- he climate of the country is strongly east (Figure 1). The land is drained with a influenced by the seasonal movement close network of rivers, lagoons, lakes, and T of Intertropical Discontinuity (ITD), streams most of which carry less water in the the boundary at the ground between the dry season. There is however a noticeable north-easterly dry continental tropical decrease in the density of the drainage airmass and the south-westerly tropical network from south to north; which has been maritime moist airmass. Rain falls as heavy attributed to the combined effect of hydro- showers with scattered thunderstorms. The climatic and geological factors. The perennial wet season occurs between July and rivers of the northern part of the country in September over the more northerly latitudes, particular have intermittent flows, occurring and increases to eight months (April to mainly during the short rainy season and are November) in the coastal area. Annual easily depleted during prolonged dry rainfall varies from 3000 mm in the south- periods. The major surface water resources of

Innovation Solution in Engineering (ISIE) 1 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Nigeria are those of: Niger River System, (Figure 2). Water stress indicator varies with Lake Chad, Western Littoral and the rivers of hydrological area (HA). While HA 8 has been Cross and Imo, in that order of importance. below the water scarcity line since 2005, HA River Niger rises in Sierra Leone and Guinea 6 reached the line in 2010. Both HA 2 and HA from where it flows in North-East direction 5 will enter the zone in 2030. Nigeria is across the country of the Gulf of Guinea, considerably below the sub-Saharan Africa with its principal tributaries being the Benue, average of about 6,500 (Cervigni et al., 2013), Kaduna, Gbako, Gurara and Sokoto-Rima and must manage these relatively limited Rivers. Its major tributary, the Benue, rises in water resources effectively if it is to reach its the Republic of Cameroon and draining the development objectives as stated in Vision Gongola, the Taraba, the Donga, the Katsina- 20-20. Yet relatively few resources are Ala and the Mada rivers. In combination, the presently being directed to critical Niger and its principal tributary the Benue development priorities, such as hydropower flow through nine countries. or irrigation.

Annual accessible groundwater resources are estimated to be 60 km3, distributed 17 percent in the north, 43 percent in the middle, and 40 percent in the south. Dam capacity nationwide is estimated at 45.6 km3. Nigeria has 106 large dams and 120 medium and small ones. Most of them serve multiple purposes (water supply, irrigation, and hydropower). In terms of water withdrawal,

Figure 1: Spatial variation of rainfall in Nigeria estimated at 8 km3/yr (5 percent of total exploitable water resources), 69 percent goes JICA (2014) assessed the water resources for agriculture, 21 percent to households, and potential of the country and reported that 10 percent to industry. average annual yield is 287 BCM for surface water within 88 BCM inflow outside Nigeria and 155 BCM for groundwater. The aggregate demand for the domestic, agricultural, power and industrial sectors continue to increase due to population growth and economic development. Mustafa (2017) examined the dynamics of population growth and water resources in the country and concluded that Nigeria is currently under the category of water stress (annual water supply is less than 1,700 cubic metres Figure 2: Water Stress and Scarcity Indices in Nigeria per person per year) countries, the situation was reached since 2005. The study further The current installed capacity of grid showed that the nation will be under the electricity is about 6,000MW, of which 65–67 category of water scarcity (when annual percent is thermal and the rest water-based. water supply is less than 1,000 cubic metres Until 1960, power production in Nigeria was per person) countries by the year 2025 mainly from coal. Construction of the first

2 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 hydropower station in Nigeria began in 1964 shortage of water supply or limitation in the at Kainji, along the river Niger. The Kainji capacity of existing infrastructure to meet plant has an installed capacity of 760 MW. water demand for domestic, agricultural and Later the tailwater from Kainji Dam was power needs. This problem can be addressed used to generate 540 MW at Jebba Dam, 97 by either increasing existing capacity of km downstream. The third hydropower existing infrastructures or through a station, the Shiroro Dam, was commissioned reduction in demand. The increase in in 1990 and has an installed capacity of 600 existing capacity implies the construction of MW, bringing Nigeria’s total capacity to capital projects, which is in competition with 1,900 MW. Between 1990 and 1999, no new limited funds. The decision between the power plant was built, and the government implementation of capital projects can be seriously underfunded both capital projects influenced by different factors. The main and routine maintenance. Figure 3 shows problem in the decision making is whether it that power generation increased annually will be economically more effective to from 1971 to 2005, but installed capacity is implement a capital project. still low and the demand–supply gap is widening. Poor energy supply has forced The cost-benefit method is the most widely many industrial customers to install their used economic tool in the evaluation of own generators, which have high costs to investment by the government, where both companies and the Nigerian economy investment leads to an increase in general alike. welfare and not financial gain. The cost- benefit analysis evaluates the benefits Among the problems of Nigeria’s power received from a project against its cost. For sector are inadequate access to the grid future costs and benefits, it is important to (estimated at only 40 percent); insufficient select the correct interest rate at which these generation capacity to meet demand; costs and benefits are evaluated to also shortages of gas for generating power; and reflect the time value of money. However, in an inefficient transmission and distribution the evaluation of water supply and system, which together add up to infrastructure schemes, the benefits consist of unreliability and frequent load-shedding. For a non-monetary indicator, water. A different reasons like these, an estimated 70 percent of form of a cost-benefit analysis is therefore electrical energy is currently produced off- needed (Hoffman and du Plessis, 2008). In grid by diesel and gasoline generators. the cost-effectiveness analysis, a non- Hydroelectric production monetary benefit is evaluated against its 9E+09 100 Hydroelectric production 8E+09 90 costs. This is also known as levelised costing Share of total electricity sources 7E+09 80 or the calculation of a unit reference value. 70 6E+09 60 5E+09 50

kWh 4E+09 40 The unit reference value method was 3E+09 30 developed for the evaluation of projects in 2E+09 20 1E+09 10 the water services sector and is widely used

0 0 to evaluate the development of new

1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 year resources. To determine the URV of a Figure 3: Annual Hydroelectric Production in (kWh) particular scheme, the primary benefit as Share in Total Energy derived from it is projected over the same period and ‘discount’ at the same rate to The continuous increase in water demand derive a ‘present value’. (van Njekerk and du coupled with climate change could result in a

Innovation Solution in Engineering (ISIE) 3 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Plessis, 2013). The URV of the scheme is scheme) at downstream of an existing dam derived by dividing the PV of the costs (PVc) (Shiroro Hydropower scheme) and (ii) a dam with the PV of the water supplied (PVw). The (Gurara II) downstream of Gurara URV evaluates all the life-cycle costs multipurpose dam with water transfer associated with the scheme in terms of its scheme to Shiroro dam. The question is present value. The method also takes the whether to (i) develop the Zungeru scheme yield of the scheme over its life-cycle into with the dam height at elevation +230 m and consideration. The yield of the scheme is the Gurara II scheme or (ii) develop Zungeru calculated on a year to year basis and only scheme at elevation +255 m. The objective of includes that portion of the yield of the the development is that both Shiroro and scheme that is actually supplied by the Zungeru Hydropower schemes meet the scheme in each specific year. It assumes that stated firm power production. This paper the yield of the scheme is equal to the thus presents an economic analysis using the shortage that would occur if the scheme was URV concept to determine the best not implemented. The URV must not be developmental option. confused with the unit cost of water. The unit cost of water differs from the URV in the THE SHIRORO-ZUNGERU HYDROPOWER respect that it represents the operating cost of SCHEME a scheme at its maximum capacity. The URV Shiroro hydropower is located on River of different projects can then be evaluated Kaduna in the north central part of Nigeria. against each other as part of the decision The dam was commissioned in 1990 with an making process for the implementation of a installed capacity of 600 MW (Table 1) next scheme to be developed. It is important bringing the total installed capacity of to note that the URV do not represent a fixed hydropower in Nigeria to 1900 MW. The value. The URV is time and site specific, as it current installed capacity of grid electricity is uses the shortage of supply of existing about 6,000MW, of which about 67 percent is schemes due to the demand under that thermal and the balance is hydro-based. specific condition, to calculate the unit Between 1990 and 1999, there was no new reference value. This means that for each power plant built and the same period new development with a specific associated witnessed substantial government under- water demand, a new unit reference value funding of the utility for both capital projects must be calculated for each option or and routine maintenance operations (World alternative. In the evaluation of options with Bank, 2012). The Zungeru Dam site is located different implementation phases, the order of on the Kaduna River downstream of the implementing these projects also affects the existing Shiroro Dam. Zungeru Dam is URV. proposed to be optimized between 88 to 113 m high dam, with two dam heights Against the backdrop of the issues raised, corresponding to elevation +230 m and +255 this paper presents a financial analysis of m at full supply level. The elevation +255 m development options under climate change is the highest possible since a higher dam scenarios in HA 2 in Nigeria. Towards would impound the tail water levels of the improving power generation for the country upstream Shiroro Dam. and achievement of sustainable development Nigeria has considerable hydro potential goals, the Government of Nigeria is sources exemplified by large rivers, small considering the development of (i) a rivers and stream. The outstanding total hydropower project (Zungeru Hydropower exploitable small and large hydropower in

4 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 the country is 12,220 MW as estimated by emission (A1B) climate scenario in medium ECN (2007). The combined installed capacity term climate analysis was adopted in the of power stations in Nigeria is far below the study. Figures 4 and 5 show the historical country’s electricity demand, resulting in and simulated flow into Shiroro and epileptic supply of electricity. The situation is Zungeru reservoirs, respectively (World compounded by the failure of the existing Bank, 2012, Cervigni et al., 2013). The power station (hydro and thermal) to operate historical and simulated flow data were at installed capacity. The inability of the adopted for this study. hydropower stations to operate at their respective installed capacity is attributed Table 1: Characteristics of Shiroro Dam

(Zarma, 2006 and Jimoh, 2010) to the Item Value following reasons: EL. Maximum power pool 382 m a s l (a) Hydrological factors, such as, (i) seasonal EL. at minimum operating 342 m a s l variation in flow to the reservoir, (ii) level inter-annual variation in flow to the Water surface Area at peak 312 sq. km reservoir, (iii) conflict among competitive Gross storage capacity 7000 Mm3

users, (iv) inefficient operation policy and Active storage capacity 6050 Mm3

(v) reservoir sedimentation. Installed power capacity 600 MW (4x150MW) (b) Non-hydrological factors, such as (i) Tail race bottom elevation 275 m a s l maintenance and spare part problems, (ii) spillway discharge at crest 7500 m3/s inadequate fund, (iii) human resources, elevation and (iv) policy issues. low water release 10 m3/s

Design power plant factor 45 % The focus of this study is the costing solution Efficiency of power system 88 % using the large dams Shiroro/ Zungeru as Maximum discharge per 180 m3/s case study. The decision is made so that the unit frequency of failures of supplying firm Average head 90.5 M 138.3 GWh/month (1660 power will not change compared to the Firm energy GWh/year) historical period (1976-2005) if the worst (source: ECN, 2007) climate change scenario occur as simulated by the Regional Climate Model (RCM) and Table 2: GCMs Used to Perturb Regional Model three other Global Climate Models (Table 2). Outputs Resolution Emission The runoff simulation output was reported Model Institution Acronym (°Lat x °Lon) Scenario by the World Bank (2012) based on the study UK HadC on climate risk analysis on water, agriculture 2.5° x 3.75° Meteorological A1B UKMO M3 and hydropower sectors in Nigeria, which Office Centre National CNRM was carried out by Centro Euro- 2.8° x 2.8° de Recherches A1B CNRM _CM3 Mediterraneo per i Cambiamenti Climatici Météorologiques Geophysical GFDL_ (CMCC), Italy. The CMCC-MED global 2.5° x 2° Fluid Dynamics A1B GFDL cm2.1 model outputs, about 80 km of horizontal Laboratory resolution (Scoccimarro et al., 2011) was used as boundary conditions to run a RCM called COSMO-CLM (about 8 km of horizontal resolution - Rockel et al., 2008) over Nigeria. The simulation was validated with observed climate along the historical period. A single

Innovation Solution in Engineering (ISIE) 5 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

is larger (meaning more capital costs) the URV works as an objective function that can be optimized. The ultimate URV is calculated from the consumer point of view, assuming no profit off-taking by the developer or the government. Increased costs because of more expensive design will be transferred directly to the consumers without subsidies. The procedure of calculating the URV (designed by the authors) is as follows: rcm = Regional Climate Model; cnr = Centre National de Recherches Meteorologiques; 1. Run the power simulation model (Box 1: gfd = Geophysical Fluid Dynamics Laboratory; ukm = Jimoh, 2010, World Bank, 2012) for the United Kingdom Meteorological Office. base design for Zungeru/Shiroro for the Figure 4: Historical and simulated inflow into Shiroro Reservoir period 1976-2005. 2. Run power simulation models for the base design for future period 2021-2065 to simulate the power deficit (difference between firm power and produced power at failures) for every year using flow data (Figures 4 and 5). 3. Identify the worst climate scenario (climate model with least rate of failure). Back-calculate how much more storage or inter-basin water transfer is needed in this worst case to achieve the same reliability as for the historical period 1976-2005.

Figure 5: Historical and simulated inflow into 4. Run power simulation models for the Zungeru Reservoir robust decision cases (increase Zungeru dam height or interbasin transfer from The cost analysis was based on the Unit Gurara II) for the 2021-2065 period to Reference Value (URV) of electricity for simulate the power deficit for every year different climate change scenarios. The using the simulated inflow (Figures 4 and metric, URV, is a measure of total unit cost 5). per kWh of firm power. The concept 5. Calculate the capital costs for the base proposed in this study is that when the case for the two case studies. hydropower plant is not able to produce the 6. Estimate the extra capital costs to meet full firm power, alternative power sources at the increased need of storage by higher costs is introduced. Alternative power increasing the dam height at Zungeru source adopted is mid-sized diesel-generator (unit costs for civil works for dams per to solve power deficits on household level. m3 storage obtained from Lahmeyer The URV increases as there is more failure (2006) and Coyne et Bellier (2007)), or for the hydropower plants to deliver the firm inter-basin transfer upstream of Shiroro power. It will also increase with capital costs. (based on the results of 5 above). Since the number of failures to deliver the 7. Set up a URV calculation in Excel for the firm power will decrease as the storage dam base case based on the following

6 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

a. Equally distributed capital costs for regard to the state resulting from the first base design of the scheme for year decision. The operation is subject to the 2017-2020 (the construction period) following constraints: b.Operation and Maintenance costs for the period 2021-2065. For new dam, (i) continuity equation: this was assumed to be 1% of St-1  It - Lt - Qt  St (2) capital cost per year for the period 2021-2040 and 2% for the period where Qt is outflow from the reservoir, Lt is 2041-2065. For existing dam (that is loss from reservoir, St is storage and It is Shiroro dam), it was assumed as inflow to the reservoir. 0.183 million US dollar per year for the period 2021-2040 and 0.366 (ii) storage constraint: million US dollar for the period Smin < St < Smaxt (3) 2041-2065. c. Cost for alternative power to cover St+1 ≤ Smaxt (4)

the power deficits for each year where Smin is the reservoir dead capacity, 2021-2065, that is the result of the Smaxt is the maximum storage at time t simulated deficits in 4 above.

d. Discount the costs to a URV using (iii) Release constraint: 10% discount rate. Qt ≥ maximum(MQt) (5) 8 Calculate the URV (US Cents/KWh) for

decision-making. where MQt is the obligatory water requirement at time t which is the release BOX 1: Stochastic Dynamic Model for from the reservoir to meet the minimum Power Simulation downstream demand (ecology, irrigation and water supply). The objective function of a reservoir system (Figure 2) is expressed as: (iv) energy production, expressed as the ft = Bt + Bt-1 + . . . . . BT + fT+1 (1) energy production capacity (EPC): EPCt = C * REQt * Ht * η (6) where Bt is the return at stage t due to the release R given the initial and final storages, where C is the conversion factor for potential fT+1 describes the value of water at the end of to electrical energy, H is the average head stage T, the last stage in the planning period over the turbine and η is the energy plant (planning period is 12 months). The benefit is efficiency. The energy that can be produced to (i) maximize the energy generated at is restricted by the plant capacity (PCAP) and energy price of N12 per KWh for firm power, number of hours available for energy penalty of N12 per KWh for deficit power production (NHP). Thus, the maximum peak and a secondary price of N4 per KWh for power produced (MPEP) is: secondary power; and (ii) minimise water MPEPt = PCAPt * η * NHPt (7) spill. The analysis starts at time T and moves backward using the Bellman’s principle The power produced at any time t is: which states that: an optimal policy has the PKEt = minimum (TEPt, MPEPt) (8) property that whatever the initial state and where PKE is the peak power produced and initial decisions are, the remaining decisions TEP is the total power that can be produced must constitute an optimal policy with at a particular time

Innovation Solution in Engineering (ISIE) 7 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

The power model was used to obtain a Volume of water required under the worst monthly release policy for each reservoir. climate scenario is 2040 Mm3 per year at a The solution to the recursive equation (1) rate of 340 Mm3 per month for six months was obtained by working backwards in time (November – April). The transfer would from the end of the decision horizon (12 entail a 67 km conveyance conduit from the months). The operation model has a number Gurara II dam site, 11 km upstream of of storage discretization (not less than 15) for Gurara falls in Niger State, Latitude each reservoir. The release policy and the 9o00’47’’N and Longitude 7o00’47’’E (Figure energy generated were used to assess the 6). In URV calculation, the deficits in firm reliability of hydropower system. Reliability power at Shiroro and Zungeru plants were or frequency of success is the ratio of the considered. The analysis was based on:- number of times the monthly power target is (i) Capital cost for +230 m dam at Zungeru met to the number of months of operation. (ii) Operation and Maintenance cost at Zungeru (iii) Capital cost for conveyance conduit (67 km) to Shiroro (the 2006 cost for 75 km conveyance line from Gurara I dam to the Federal Capital Territory is 3.9 million USD per km. This rate was assumed for Gurara II project. Notation: I is inflow, Q is release, S is storage, L denotes losses including evaporation and seepage, (iv) Operation and Maintenance of the REQ is the discharge through the turbine and ORQ transfer system represents release for other uses (irrigation, water (v) Operation and maintenance of the supply, downstream requirement), and t denotes time. existing Shiroro scheme, Figure A1: Schematic diagram of a reservoir system (vi) Cost of meeting power deficit.

Variation in deficit power supply (b) Increase Zungeru dam height Table 3 shows the deficits in firm power for This option involves increasing the dam 2016-2065 in Shiroro and Zungeru plants height at Zungeru for the purpose of respectively, assuming that the construction increasing the reliability of supplying firm of Zungeru plant is between 2017 and 2020. power at Zungeru in a worst climate scenario The deficit in firm power varies with model, (‘rcm model’). Increasing the dam height in agreement with the seasonal variation in from +230 m to +255 m, the maximum simulated flows. The RCM model indicates possible height, without impounding the tail the highest deficit, followed by GFD model. water of Shiroro reservoir, will reduce the The UKM and CNR models projected deficit in firm power by 89%. Since +255 m is surplus flow in the HA, resulting in sufficient the maximum dam height possible, the flow to meet firm power at the respective additional dam height required for this power station. option is 25 m, and the capital cost for +255

m dam with 500 MW capacity is 1647.11 ADAPTATION OPTION million US dollars (2006 price level). (a) Inter-basin water transfer to

Shiroro/Zungeru scheme

This option involves the transfer of water during dry season (November – April) from Gurara II Project to Shiroro Reservoir.

8 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Table 3: Deficit in firm power (GWH) at Shiroro and Zungeru hydropower plants Shiroro Zungeru Year cnr gfd rcm ukm cnr gfd rcm ukm 2016 0 0 0 0 0 0 0 0 2017 0 0 0 0 0 0 0 0 2018 0 0 0 0 0 0 0 0 2019 0 0 0 0 0 0 0 0 2020 0 0 0 0 0 0 0 0 2021 0 0 0 0 0 0 68.7 0 2022 0 0 0 0 0 0 119.55 0 2023 0 0 0 0 0 0 0 0 2024 0 0 88.99 0 0 0 175.1 0 2025 0 0 0 0 0 0 112.68 0 2026 0 0 0 0 0 0 0 0 2027 0 0 0 0 0 0 0 0 2028 0 0 0 0 0 0 0 0 2029 0 0 0 0 0 0 0 0 2030 0 0 0 0 0 0 0 0 2031 0 0 0 0 0 0 0 0 2032 0 0 0 0 0 0 0 0 2033 0 0 0 0 0 0 0 0 2034 0 0 0 0 0 0 0 0 2035 0 0 0 0 0 0 57.61 0 2036 0 0 0 0 0 0 83.54 0 2037 0 0 0 0 0 0 0 0 2038 0 0 0 0 0 0 0 0 2039 0 0 138.3 0 0 0 310.54 0 2040 0 0 0 0 0 0 113.76 0 2041 0 0 0 0 0 0 0 0 2042 0 0 0 0 0 0 17.62 0 2043 0 0 0 0 0 0 48.82 0 2044 0 0 0 0 0 0 13.91 0 2045 0 0 0 0 0 0 86.01 0 2046 0 0 0 0 0 0 14.84 0 2047 0 0 0 0 0 111.73 229.02 0 2048 0 0 207.36 0 0 31.32 375.14 0 2049 0 53.33 276.6 0 0 319.5 407.3 0 2050 0 162.96 0 0 0 477.3 0 0 2051 11.42 0 0 0 0 104.62 0 0 2052 0 0 0 0 0 0 0 0 2053 0 0 403.08 0 0 0 421.31 0 2054 0 0 837.11 0 0 0 1156.84 0 2055 0 0 12.83 0 0 0 140.32 0 2056 0 0 0 0 0 0 0 0 2057 0 0 0 0 0 0 0 0 2058 0 59.22 0 0 0 79.96 0 0 2059 0 0 0 0 0 136.8 229.24 0 2060 0 0 304.07 0 0 48.05 600.62 0 2061 0 0 451.32 0 0 0 736.83 0 2062 0 138.3 29.68 0 0 63.03 151.91 0 2063 0 0 481.47 0 0 0 609.42 0 2064 0 0 859.96 0 0 69.08 1171.17 0 2065 0 107.91 11.68 0 0 313.16 133.87 0 rcm = Regional Climate Model; cnr = Centre National de Recherches Meteorologiques; gfd = Geophysical Fluid Dynamics Laboratory; ukm = United Kingdom Meteorological Office.

Innovation Solution in Engineering (ISIE) 9 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Table 5: Summary URV calculation for inter-basin water transfer to The URV calculation for the ‘rcm’ model Shiroro/Zungeru scheme using the inter-basin water transfer scheme URV_10_diesel is presented in Table 4. The summary of the interbasin height inc %diff URV values for the four models is presented cnr 16.76 40.36 241% in Table 5. The URV for interbasin scheme is gfd 37.54 46.93 125% 139.32 US cent/KWh (N515/KWh) for the rcm 139.32 210.04 151% worst climate model and 16.76 US ukm 16.69 40.36 242% cent/KWh (N62/KWh) for the best climate model. Under the increasing dam height, CONCLUSION the worst climate model has a URV of The reason for the decreased reliability in 210.04 US cent/KWh (N777/KWh) and 40.36 the worst case is a combination of predicted US cent/KWh (N149/KWh) for best climate lower magnitude and more variable inflows model. The URV (US cent/KWh) varies with to the hydropower dams. The consequence the climate model, with UKM model giving of increased failures to deliver firm power, the lowest value for both interbasin water in a situation where Nigeria in general transfer and increasing height of Zungeru remains to suffer power deficits, is more dam. In all the models, the URV for load-shedding transferring costs to the interbasin transfer option is lower than that consumers, who need to supplement the of increasing Zungeru dam height. Thus, it electricity demand through private diesel is more economical to develop Zungeru generators at high unit cost. Two options dam at dam height +230m and develop were considered in mitigating the power Gurara II with water transfer to Shiroro deficit due to climate variability. The URV reservoir. The relative increase in URV for technique was adopted in assessing the increase dam height over interbasin transfer economic feasibility of the options. In all the varies from 125% to 242% for discount rate four climate models considered, the URV 10%. The relative increase in URV of for interbasin transfer option is lower than increase in dam height over interbasin that of increasing Zungeru dam height. The scheme remains same with discount rate of relative increase in URV for increase dam 6% and 8%. These findings are consistent height over interbasin water transfer varies with Hoffman and du Plessis (2008) and van from 125% to 242%. Thus, increasing dam Niekerk et al. (2013). height is not a suitable option under an active or inactive government policy.

10 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Figure 6: Location of Dam sites

Table 4: URV Table for inter-basin water transfer to Shiroro Reservoir (Using RCM model data set)

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Lahmeyer (2006). Mambilla Hydroelectric REFERENCE Project, Draft Bankable Feasibility Cervigni, R., Valentini, R. and Santini, M. Study, Lahmeyer International, June (eds.) (2013). Toward 2006 Climate‐Resilient Development in Mustafa, S. (2017). Water scarcity and Nigeria, Directions in Development. security implications for Nigeria. Washington, DC: World Bank. Proceedings of the 8th International Coyne et Bellier (2007). Zungeru Conference of the Nigeria Association HydroElectric Project. Updated of hydrological Sciences, pp.41-52. Package. The Federal Republic of Rockel, B., Will, A. and Hense, A. (2008). The Nigeria. Ministry of Power and Steel. regional Climate Model COSMO- ECN (2007). National Energy Databank. CLM (CCLM), Meteorologische Assessment of Small Hydropower Zeitschrift, 17 (4): 347-348. Resources in Nigeria: River Basin by Scoccimarro, E., Gualdi, S., Bellucci, A., River Basin. Energy Commission of Sanna, A., Fogli, P. G., Manzini, E., Nigeria (ECN), Federal Ministry of Vichi, M., Oddo, P. and Navarra, A. Energy. (2011). Effects of Tropical Cyclones on Hoffman, J. J and du Plessis J.A. (2008). Ocean Heat Transport in a High Water demand management: An Resolution Coupled General economic viable option. Proc. of Circulation Model. J. of Clim. doi: Water Institute of South Africa 10.1175/2011JCLI4104.1 Biennial Conference, Sun City, South van Niekerk, P. H. and du Plessis, J. A. (2013) Africa. Unit Reference Value: Application in JICA (2014). The Project for Review and appraising inter-basin water transfer Update of Nigeria national Water projects. Water SA Vol, 39 No.4: 549- Resources Master Plan. Volumes 1, 2, 554. 3, 4 and 5. A study by Japan World Bank (2012). Nigeria: Enhancing the International Cooperation Agency resilience of development to climate (JICA) for the Federal Ministry of change, Report No: 69027, Water Resources, Abuja, Nigeria Washington, DC: World Bank. Jimoh, O. D. (2010). Optimal Operation of Zarma, I. H. (2006). Hydro Power Resources Hydropower Systems in Nigeria. in Nigeria. Being a country position

Tech. Trans. National Centre for paper presented at 2nd Hydro Power Hydropower Research and for Today Conference International Development, University of Ilorin, Centre on Small Hydro Power (IC- vol. 1: 8 -21. SHP), Hangzhou, China.

12 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

INNOVATIONS IN WATER AND ENVIRONMENTAL INFRASTRUCTURES

Agunwamba, Jonah Chukwuemeka Department of Civil Engineering, University of Nigeria, Nsukka. [email protected]

ABSRACT Many countries in the world have embraced innovation as an instrument for the creation of sustainable change that will drive the all needed innovation. The ability to develop new ideas and innovation has become a priority for many countries. Intense global competition and technological development have made innovation a source of competitive advantage. The general barriers to innovation in Nigeria include basic infrastructures, defeatist thought pattern, wrong approach and misconception of the nature of research amongst others. On the water supply side are aging infrastructure, unregulated water price, poor water quality, and access to water. Examples of innovations in the area of water and environmental engineering both in Nigeria and the developed countries were also presented. Research support and empowerment through training and sponsorship were identified as the important drivers of innovation.

Keywords: Water Supply, Research, Innovation, Pollution

1. INTRODUCTION these is the increasing cost of energy and the need to reduce energy consumption because 1.1 Definition of its global earth warming effect and climate An innovation is the implementation of a change. Dwindling financial resources which new or significantly improved product (good is one of the main drivers of innovation, or service) or process, a new marketing aging infrastructure and increasing public method, or a new organisational method in demand for better control of pollution, add business practices, workplace organisation or more to the complex situation. At the bottom external relations (OECD, 2005). The three of all these is the realization that innovation, stages in the process of innovation are new practical solutions to problems in terms invention, translation and commercialisation. of reduced cost, ease, sustainability and Generally, it is not enough to invent. The efficiency, is the key. invention must be implemented and marketed. Hence, generating or realising a Unfortunately, innovation has not been new idea (invention and creativity) and within the purview of many developing implementing and marketing countries including Nigeria. Development (implementation) is the whole essence of has been stunted for many years and several innovation. issues have hampered innovation, especially in water and environmental engineering. Generally, innovations in the water and environmental engineering sector are driven The aim of this paper is to present a brief by needs. The world as a whole is grappling status of water and environmental with many complex problems needing engineering in Nigeria, highlight the barriers urgent attention and requiring conflicting to innovation and some of the innovative resources to solve them. At the centre of all

Innovation Solution in Engineering (ISIE) 13 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 solutions being proffered worldwide, and From Epanet and Watercad analysis of the discuss the areas innovations are needed. distribution network Makurdi, the following problems were identified: Undersized pipes, 2. STATUS OF WATER AND wrong placement of valves in the system, ENVIRONMENTAL ENGINEERING and very high velocity in the system which INFRASTRUCTURE was as a result of low friction and subsequently pipe burst. In addition, the 2.1 Water Supply design population has been exceeded which According to WaterAid, over 130 million increased the draw out from the system people do not have adequate sanitation in causing instability in the system (Ekwule, Nigeria and 57 million do not have access to 2018). safe water. In addition, sixty thousand children under the age of five die every year The existence of several boreholes some of from diarrhoeal diseases caused by poor which were constructed without appropriate water and sanitation (http://www. feasibility studies, are not sustainable. The wateraid. org/ng). In 2012, the WHO interference among the boreholes dug close ranked Nigeria 3rd behind China and India together in the face of climate change as countries with the largest population presents a future precarious situation of without adequate water supply and groundwater depletion. sanitation. The collapse of the water corporation and institutional capacity. One of 2.2 Air Pollution the problems of water vendoring is lack of Air pollution is prevalent in the major urban recognition by the government. Recognising areas. The sources range from disturbed them as part of regulatory framework will particulates and gave rise to the burgeoning assist in the realization of MDGs target of local water vendors who supply water (Ayalew et al., 2014) while safeguarding through tankers from public and private extensive surveillance will ensure safety boreholes. The immediate consequence is (Sheshe and Magashi, 2014). The prices the lack of control of the quality of water package water providers market their supplied to the public for domestic uses products are not regulated. Hence, what Analysis of water samples collected from could have been generated by the different locations indicate that often times government by having in place an low quality water products are sold in the economically viable provider is lost. market, thereby jeopardising public health (Agunwamba and Eze, 2005; Dada, 2009). In Even where the public model still exists, it is addition, there is a lack of water quality still struggling to keep afloat. Some sources awareness among many water vendors of water from public utilities and unlined (Ahmad, 2016). Dada (2009) proposed wells are polluted (Jeje, and Oladepo, 2013). intervention in three areas – adopted Pure neglect, lack of maintenance regulatory approach, collaborative programme for replacement as the pipes age, stakeholder partnerships dusts from un- and dwindling of funds have paralysed tarred road surfaces to gaseous emissions several public utilities which used to be from automobile, industrial chimneys, responsible for water provision in many homes, generators, incinerators and open air townships (Agunwamba, 2000; 1994; Hassan burning (Godwin et al., 2015). There are no et al., 2016). emission control facilities fitted to vehicles to control air pollution and no form of

14 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 monitoring to detect the presence of these for the above engineering operations. An harmful substances in the air. Poorly under drain and a treatment plant for the maintained vehicles are allowed to join the leachates as well as an interception drain are traffic, thereby polluting the air the more. usually constructed around the sanitary land The consequence of this neglect is exposure fill. Most disposal sites in Nigeria lack these of the general public to health problems infrastructures. The sites are simply where (Agunwamba et al., 2009). wastes are dumped and burned and scavengers operate to identify and collect Diseases like eye inflammation, respiratory reusable materials. The haphazard and diseases and toxicity. Air quality control unscientific manner of operation of solid gadgets should be installed to monitor the waste dumps results in pollution of soil, air level of pollution in public places like and water bodies (Agunwamba and Udedeh, schools, parks, markets, clubs and so on. 2009). Toxic fumes and greenhouse gases are Vehicles should also be fitted with emission produced by precarious in situ burning indicators. which could have acute or chronic health and environmental consequences. 2.3 Solid Waste Infrastructure The problems posed by improper and In Nigeria, more than 98% of the budget is ineffective management of Municipal Solid spent on collection whereas in the developed wastes (MSWs) have become an issue of countries it is the other way round global concern over the past decades. High (Agunwamba, 1998; 2007). A study in 2003 population density on one hand and by the health and Demography department inadequate facilities on the other are among of Nigerian National Population Commission the problems that hamper effective solid indicated that only 14% of Nigerians have waste management. In spite of the publicity access to reliable household waste disposal and public outcry solid waste attracts, the system. About 87% of Nigerian allegedly level of waste management in many cities used unsanitary disposal system (Oyekan remains poor. The much that goes for refuse and Sulyman, 2015). A very good review in management is removal of the waste from this subject is presented by Tariwari et al. public view and transferring it out of sight 2017). where it is abandoned to pollute surface and ground water and provide harbourage for The infrastructure for solid waste storage, collection, transfer, processing and disposal disease vectors (Adebara et al., 2016). Proper are either inadequate or completely disposal will involve first feasibility study for absent. This results in infrequent waste selection of the appropriate site, bearing in mind the danger the waste creates to the removal, ground dumping, litter, and good environment if it is not appropriately habourage for disease vectors. handled. Once a good site is selected, the 2.4. Wastewater waste is deposited on the prepared site, The indiscriminate discharge of wastewater levelled, compacted and covered with effluents and municipal sewage into rivers borrowed soil of specified quality. All these jeopardizes to a great extent the health of precautions are taken to minimise the aquatic living organisms. For a safe production and accumulation of leachates. In sustainable environment, there is a need for addition, some equipments such as proper assessment of streams and rivers in bulldozers, compactors, rollers, pay loaders Nigeria to ensure waste discharge within a and excavators are usually provided on site stream assimilation capacity which will

Innovation Solution in Engineering (ISIE) 15 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 subsequently result in improved water quality and optimum utilization (Adedekun and Agunwamba, 2014). Some companies create make-believe tanks 3.1 General Barriers just to satisfy the curiosity of the Several barriers hinder innovation in water environmental monitoring team and avoid and wastewater engineering. Some of the litigation. This has resulted in industrial factors stem from lack of concern for pollution of water bodies, which results in development in the industry to the eutrophication, reduction in water quality, suppressive atmosphere occasioned by toxicity of aquatic living organisms and psychologically debilitating environment of sometimes fish kills. The growth of excessive lack of basic infrastructure. When there is a weeds results in slowing down of flow lack of basic infrastructure such as water and velocity and subsequently siltation increases. power supply even the most innovative With time the surface water is silted up mind fritter away his creative time on completely or its morphology is altered. The struggling to stay focused. Several weed exerts an oxygen demand on the river, researchers who have the zeal in effecting reducing the oxygen available for utilization technological changes about their by aquatic organisms. With continued flow environment have ended up growing cold of untreated or partially treated effluents because of repeated failure on the part of the from industries and fertilizers, herbicides government to provide a certain level of and pesticides from irrigation fields coupled enabling environment. with poor un-conservative catchment area practices, siltation and eutrophication have However, while some researchers appear to continued unabated. Many surface water have lost hope in the system, a ray of hope bodies may disappear in the future. still flickers in the minds of a few researchers. The barriers to innovation, especially in the 3. BARRIERS TO INNOVATION developing countries are many. The list Innovation is important for the survival of a presented by Rick (2013) could be classified nation. New technologists, new products, into seven aspects, most of which have to do new services, whole new industries have with wrong beliefs and faulty reasoning. emerged through innovation. Undoubtedly, These are lack of shared vision, faulty it is a key required for improving thinking pattern, impatience, wrong belief, productivity, growth and business and poor reward system. sustainability. However, certain factors often impede the rate and form of innovation. The 3.1.1 Lack of Shared Vision, Purpose barriers to innovation are many and include and/or Strategy (Speight, 2015 (1) lack of state policies to Nothing is more truthful than the scriptural support technology and R & D activities; (2) statement: ‘My people perish for lack of negative impact of the economy on the level vision’. Vision has to do with the plan you of investment; (3) high cost of innovation; (4) have; purpose, is what you intend to achieve lack of appropriate means of financing while strategy is how you intend to achieve innovation; (5) lack of qualified personnel; (6) it. lack of specialists; (7) equipment technology; (8) standards and legislation;(9) lack of 3.1.2 Faulty Thinking Pattern capital; (10) the lack of consumer response; Many people cannot stay quiet and and (11) the infrastructure of the business. concentrate to think objectively, they might

16 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 end up being harassed by unwholesome expectation comes too soon before thoughts, they are afraid, they therefore meaningful results are realised, can be become afraid to think. Unfortunately, demoralizing. The task of achieving without organised and focused thought significant innovation in water and pattern there will be no innovation. People environmental engineering can be very with short thinking span lack definite tedious. This involves creating significant priorities, and are unsystematic in their changes and should not be done in a hurry, if thought pattern. it is targeted at affecting lives.

One of the major barriers to innovation is not 3.1.6 Risk Aversion setting time aside for thinking. Productive Risk Taking is involved in every aspect of thinking requires not only time but also life. Only a dead man will not take one kind skillful brainstorming as well as addiction to of risk or the other. Risk aversion can hinder the left-brain. innovation. Although undue fear because of risk should not be a constraint, there is need 3.1.3 Wrong Belief for careful analysis of risks involvement in an Wrong belief will keep someone from being innovation before one embarks on it. innovative, focusing on past failures without letting go, fear of criticism and the 3.1.7 Underfunding unwillingness to change have made several Another serious barrier to invention is innovators unproductive. This is one of the underfunding. A close interaction with some important areas Nigerian innovators need to people showed they have innovations at work on themselves. So much water has different stages of development. However, flowed under the bridge. Nigerians need that lack of funds is hindering the full realization belief in themselves to realise that the nation of their dreams. Funds are needed at every can still rise and take its enviable position stage of innovation, from conception of the among the league of nations, if the right idea, incubation period to turning the idea policies are put in the right place with the into a tangible finished product. right people. 3.2 Research Barriers 3.1.4 Poor Reward System Many research works have been done in The reward system in Nigeria where Nigeria in water supply, water quality, water sometimes those who do not work hard treatment and environmental pollution. benefit most can be very demoralising. To However, the purpose of some of those motivate hard work and innovative spirit, researches have not been achieved because of which will drive the desired technological various barriers, and they are as follows: advancement, a good reward system, from the civil service to the private sector, where 3.2.1 Poor Funding hard work and diligence is appreciated The level of funding of research continues to should be established. be poor. According to Bogoro (2014), the contribution of the private sector to research 3.1.5 Impatience in Expectation of Payoff is only 0.2% where as in the developed Another barrier to innovation is the quick countries it is up to 70%. Lecturers who expectation of payoff. Payoff which is a form could not access grants often fund researches of reward should be expected in an from their salaries. The consequence is that innovative process, but when this most researches are superficially and

Innovation Solution in Engineering (ISIE) 17 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 haphazardly executed up to the degree the some competing socio-economic demands researchers’ personal funds can support. In (Owlia and Mirzaei 2014). addition, the findings are based on poorly designed experiments and inadequate data, which reduces the confidence on the 3.2.4 Relevance of Research findings. Another barrier to optimum research output in water and environmental engineering is Generally, the budgetary allocation to non-relevance of some of the researches to education in Nigeria is low (about 6% as national development. Solving real life against the 26% proposed by the United problems satisfactorily often require huge Nation (Olanrewaju, 2017. See also financial investment and long term https://www.premiumtimesng commitment. The zeal and interest in such .com/news/top-news/218097-2017-budget- in-depth work are lacking. There are no nigeria-fails-meet-un-benchmark- sustained efforts in prosecuting research. education.htmls). This percentage is just 0.219% of the GDP based on 2007 UNESCO 3.2.5 Reward Structure statistics. This is a big contrast to the statistics The interest of an academic is further of the developed countries. For instance, dampened by lack of institutional structure Denmark’s expenditure in 2013 was 3% of to acknowledge and reward his research the GDP (US $7,884.3M). Research spending efforts. It has been said that most researchers by 10 countries alone was almost US $ 1.7 stop active involvement in research as soon trillion, accounting for 80% of spending as they are promoted to the post of whereas the spending for the whole of sub professors. How could very significant Sahara was only 0.5%. outputs be obtained when the very persons who are supposed to champion research are 3.2.2 Repetition no longer interested in it? Before anyone Repetition of work done by other researchers would cast the first stone on researchers is a common feature. While there could be a notice that some of these category of good reason to repeat the investigation of a researchers, though ardently interested research work, for instance, to validate a before been promoted, had denied previous one done, most of the repeated themselves most comfort their salaries could research works are done without the acquire them for research. After been researcher’s awareness findings of the other professors, with no further motivation, they researchers (Owlia and Mirzaei, 2014; are faced with the challenges of riding better Opryszko, 2009) cars and building houses or setting up businesses in preparation for their 3.2.3 Disjointed Research Efforts retirement. Some of the research work done in water and environmental engineering are disjointed, 3.2.6 Impact Factor lacking in structure and sustained purpose. Most of the national journals do not have Some of the researches are executed without impact factors. Since some high impact-factor long term vision. The research works are not foreign journals would not publish findings related to the industrial needs of the country. that are not of international interests, seeking Someone starts a research programme but for publications that have wider relevance cannot bring it to a fruitful end because of forces a researcher to focus more on topics that are of international relevance.

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Researchers are involved in research to who will understudy them through a satisfy the needs for promotion and not out gradual replacement process. of interest in solving local problems useful in national development. When a researcher in Almost entirely new employees, who are the peak of his career, targeting to be a usually employed to satisfy accreditation professor within minimum time, constrained requirement, resume duty almost as their by lack of fund, research facilities and senior and more experienced colleagues are institutional promotion requirement; when leaving. The consequence is that most of the in a bid to be promoted he is infected by the new staff hired lack vital experience in ‘impact-factor fever’, he would not be equipment handling and conduct of interested in solving local research problems. experiments.

3.2.7 Applications of Research Results Starved of fund, most universities complain Even when there are important findings that they could not fund the training of supported by well executed research, the technologists. Technological advancement government is unwilling to conduct a test on and innovation may also depend on the the findings and if necessary, promote and contributions of technologists. However, commercialise it. Important research findings where those technologists who work hand- are lying abandoned in some libraries and in-hand with researchers are ignorant or workshops robed all over with cobwebs on a worst still are not familiar with the basic thick layer of dusts. Lack of proper laboratory procedures, they are bound to framework for application of the research obtain misleading results. findings, impacts negatively on the researchers’ willingness to perform research The researcher have had several experience for national development. Researchers could of that sort where the parameters such as litter journals with their research outputs, but BOD and DO obtained during laboratory those research findings require further experiments were very unrealistic. The research and government input to bring the problem is compounded when the findings to the point where they could be experiments are conducted by fraudulent applied. But because of lack of vision and technologists who ‘cook’ the results, or proper framework for further development innocent technologists who use faulty or un- and application, the findings are lost in the calibrated equipment or bad reagents. If the libraries. present generation of technologists were to master the use of modern laboratory 3.2.8 Problems of Technologists equipments and keep abreast with The role of well trained and experienced innovations in the industry, then they should technologists cannot be overemphasized in be properly trained. research and development. Over the years, the pool of experienced technologists in some 3.2.9 Lack of Depth institutions of higher learning has continued Due to fund constraints, some research work to dwindle either due to retirement done in Nigeria are not in depth. Although incomplete. It is very difficult to replace this some of the topics are well formulated, the calibre of staff who had acquired much experiments backing them are terminated experience through hands-on-the-job. Yet, abruptly. Either the researchers are in a there is no planned strategy to recruit staff hurry to publish or they lack the financial backing to conduct the research to a

Innovation Solution in Engineering (ISIE) 19 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 conclusive end. At the end, the pathways of composite nano-particles, to emit silver ions the researchers are littered with many for destruction of contaminants. Another unfinished projects, resulting in wastage of innovation is the applications of membrane time and resources. technology. Membranes, through which water by passes to be filtered and purified, 3.2.10 Large Data Requirement are integral to modern water treatment Another problem facing researchers in processing. The pores of membranes used in Nigeria is the large data requirement of ultrafiltration can be just 10 or 20 nanometres experiments conducted in some fields. This is across – 3,000 times finer than a human hair. very important, especially in environmental engineering where much data is usually Recent breakthroughs have led to reduction collected to define the spatial and temporal in the cost of desalinated water from $1 per variation of a parameter. High chemical cost, cubic metre to between $0.80 and $0.50 over the need for sustained sampling and five years. New ceramic membranes are laboratory analysis and the requirement to helping to make treatment more affordable. capture both the spatial and temporal However, the cost of desalination is still high variations of the parameters for meaningful and more cost effective technologies are inference, makes research in environmental needed. engineering very expensive. In developing countries alone, it is estimated 3.2.11 Premature Conclusion that 45 cubic metres are lost in distribution Sometimes, inadequate time is spent on data networks. Leaks are costly for companies as collection, thereby hindering verification and they increase pressure, stress water drawing meaningful inference. Sometimes resources, and raise the likelihood of the assumptions for application of the pollutants infiltrating supplies. New statistical models are never satisfied. In fact, monitoring technologies, such as pressure experiments are often conducted without and acoustic sensors, connected wirelessly in researchers being knowledgeable about the real time to centralised and cloud-based limitations inherent in the theoretical monitoring systems, will allow the detection background of their work. of leaks much quicker.

4. CASES OF INNOVATIONS IN Other innovations include new technologies WATER AND ENVIRONMENTAL for wastewater reuse, nutrient removal, ENGINNEERING mobile recycling facilities, and so on (Clancy, Some innovations are being made all over 2014). These innovations are not without the world in the area of water and waste huge financial investment. water engineering as people recognize innovations as drivers of development in the 5. AREAS OF INFRASTRUCTURAL society (Dirks and Moeller, 2017). A very INNOVATIONS brief summary of those innovations are The following aspects of water and presented below (USA EPA, 2017; Speight, environment require innovation: 2015; Henley, 2013). 5.1 Organization of scavengers The use of nanotechnology has resulted in Scavengers recover useful materials from the improved technology where microbes, waste stream. Though significant and bacteria and other matter from water use extends the life span of landfills, their roles

20 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 are not appreciated. They lack the necessary protection against health-hazardous activities Waste stabilization pond, another low cost associated with their work. Innovations are treatment plant popular in Nigeria, has required in the aspect of capturing more undergone some innovations with respect to recyclables from the waste stream and its large area requirement. This limitation has organizing them into a more orderly and been removed by the introduction of a new acceptable structure with emphasizes on technology, Integrated Solar and Hydraulic health and safety and maximization of the Jump Enhanced Waste Stabilization. Bacterial economic benefits of employment and removal in this new pond was found to be as development of small scale enterprises. The much as 50 times better. The advantage of relevant institutions should then be capable this technology is the construction of WSP in of empowering them for a higher standard of congested urban areas with savings in land living while generating income from the cost while achieving higher efficiency sales of recycled materials. (Agunwamba, 2001; Ogarekpe and Agunwamba, 2015). 5.2 Efficient Technologies More efficient technologies to enhance waste 5.5 Models recycling should be provided in the Efforts should be made to create innovative conversion of waste into energy and other alternative construction materials and resources such as biogas, organic fertilizers, designs that are more affordable, sustainable, construction materials, amongst other. suitable and efficient. Adaptation of existing technologies that requires more research is 5.3 E-Waste Management needed so as to achieve better efficiency. Such wastes include refrigerator barrels, Many technologies in water and wastewater computer components and other parts that engineering are simply applied directly to could be recovered (Eneh and Agunwamba Nigerian environment without due 2011). The rate of generation of all kinds of e- consideration of the effects of different waste is astronomically high as computer environmental conditions existing where repair companies replace several components those technologies were introduced. daily. Urgent attention is needed in finding alternative uses and recycling mountainous 5.6 Materials piles of e-waste. Investigation of the effectiveness of local materials in water and wastewater treatment 5.4 Wastewater Infrastructure has attracted much attention. Such materials Having more compact and efficient include Moringa seed, both in its deoiled and wastewater treatment systems that occupy ordinary form for coagulation and less space is important, especially in the disinfection; activated carbon from maize urban areas where land is scarce. Efforts are cob, Terminalla Cattapa, bamboo, palm needed in research to find systems that kernel shells, periwinkle, wood and others. leverage on the simplicity of the on-site The investigations centred on the adsorptive treatment systems while maximising their properties of the activated carbon and treatment efficiencies. In spite of the rampant isotherms produced under varying use of the septic tank system in waste water temperature, sequence of carbonation and treatment, the technology still requires activation and operating conditions such as innovation in improving its microbial dosage, pH and so on (Udeh and removal efficiency. Agunwamba, 2017).

Innovation Solution in Engineering (ISIE) 21 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

universities. Research problems are taken to Although such experiments have yielded the universities to proffer solutions to them. very promising results, further experiments As the problems are solved, the universities are required to examine the performance of as well as the individual researchers and the the activated carbon from these sources companies benefit. Universities and research under industrial conditions. This is also organizations should explore other sources applicable to bioremediation. of funding if they will remain relevant and competitive. Also, enabling environment The use of locally existing plants for removal through legislative and capacity enablement of wastewater pollutants has also been should be provided. explored (Agunwamba et al., 2013). The findings reveal that the absorptive Collaboration between the university and the capabilities of these plants are high and they industry is very necessary. This can be could be used for treatment. It is very achieved if industries can constantly fund important to perform a critical comparative universities researches in new areas that can study of the performance of these materials facilitate innovation. Such funding will and determine their effectiveness, cost provide the state of the art equipment for implications and affordability, to reveal the research, equip the academia with new gaps in knowledge for further research and knowledge, create innovativeness and show the optimal path needed for their advance the reputation of the university. commercialization or further research. Allocation to research should be increased while universities and research Centres Achieving alternative cost effective treatment should commit themselves to addressing of water and wastewater, suitable to local societal demands. conditions would have made waste treatment more popular. As it is, many 5.8. Wastewater Re-Use industries do not treat their waste before Another area of importance is wastewater discharging to nearby water bodies. reuse. Sewage waste water from homes is Monitoring to checkmate pollution of water wasted because of lack of plan for reuse. It bodies has been very ineffective because of should be put into reuse in irrigation to boost corruption, incompetence, and ignorance of agricultural production and free more water the associated public and environment for domestic use, especially in the semi-arid impacts. Some systems in water and region of Nigeria (Adewumi and Oguntuase, environment require in-depth research so as 2016). to collate areas, identify the gaps, fill the gaps in knowledge and use the data to produce 6. CONCLUSION AND manuals for guiding engineers in design. RECOMMENDATIONS This paper reviewed the status of water and 5.7 Synergy between Research waste water infrastructures in Nigeria. Institutions and Industry Generally, the state of the infrastructure is A new level of synergy between government, poor due to lack of good maintenance policy. industry and Universities and other research There are virtually no innovations in this institutions to boost research is necessary. In area because of the barriers of poor attitude the most advanced economies of the world, to research, low research funding, depressive industries and others in the organized environment, low infrastructural base private sector fund research in the amongst others.

22 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

The following recommendations are made: 6.6 Synergy between Research 6.1 Innovative Way Institutions and Industry New ways to generate the supply of water A new level of synergy between government, through reuse, conservation and adaptation industry and universities and other research of some existing innovations to Nigerian institutions to boost research is necessary. In environment should be explored. the most advanced economies of the world, industries and others in the organized 6.2 Research Burden private sector fund research in the Funds should be raised from NGOs to universities. Research problems are taken to embark on intervention projects in water the universities which proffer solutions to innovation and to give more research grants them. As the problems are solved, the to deserving individuals. The private sector universities as well as the individual should be encouraged to be involved in researchers and the companies benefit. equipping the institutions of higher learning. Universities and research organizations Several sanitary, environmental and water should explore other sources of funding if laboratories in universities have far less they will remain relevant and competitive. equipment than is needed. The private sector Also, enabling environment through could equip these laboratories where they legislative and capacity enablement should could conduct their material tests. be provided.

6.3 Identify Innovation Industries can constantly fund universities The relevant government body should researches in new areas that can facilitate identify works in different universities that innovation. Such funding will provide the have high potential of contributing to state of the art equipment for research, equip innovation for possible sponsorship while the academia with new knowledge, create holding workshops to educate the innovativeness and advance the reputation beneficiaries on the importance and roles of of the university. Allocation to research innovation in boosting the national economy. should be increased while universities and It should also promote capacity development research Centres should commit themselves programmes that deliver innovation as part to addressing societal demands. of their curriculum. In addition, it should adopt incentives to stimulate and reward Problems facing the country in water and the research in the water sector. environment should be identified and listed and relevant experts in the universities, 6.4 Demand Driven whose performances should be monitored There should be a shift toward demand- from time to time, commissioned to conduct driven and market-driven innovation rather research on them. Across university and than just R and D focused innovation multidisciplinary research should be models. Besides, the culture of innovation encouraged to leverage on the unique can be promoted by establishing a centre of strengths of all the universities. excellence for innovation in the Ministry of Science and Technology. 6.7 Improved Energy System

The structure required for reduction of 6.5 Infrastructure carbon emission should be worked out and The issue of decayed water infrastructure commitment made towards achieving the should be addressed.

Innovation Solution in Engineering (ISIE) 23 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 reduction. There should be a paradigm shift and environmental safety should be if significant reduction in carbon is to be introduced. achieved. Energy reduction needs to be considered holistically throughout the whole 6.10 Alternative Materials sectors. There is the need for energy There should be research on alternative optimised conventional water treatment packaging materials that are more technologies. biodegradable to replace cellophane materials. There should be renewed focus on water with greater emphasis on climate change 6.11 Plumbing materials mitigation, catchment management to tackle Emphasis should be placed on technological diffuse pollution at source and achieve advancement to significantly extend the greater water savings by boosting efficiency. usable life of pipes. There should be an R & D in the areas of optimising energy use adoption of sustainable method of powering in treatment technologies, developments in water pumps other than dependence on low energy-use pumping, increasing the fossil fuel as well as optimisation techniques availability of renewable energy, increasing to reduce energy inputs. Other sources of biogas recovery and development of carbon power such as wind energy should be foot – printing methodology to aid the move explored. The Standard Organization of to the delivery of a carbon – neutral/carbon Nigeria should develop and apply standards negative service with respect to plumbing materials to checkmate the influx of low quality products 6.8 Funding into the Nigerian market as well as to uphold Funds allocation should be done in a manner standards of practice in the water sector. to encourage companies to pursue Other sustainable hydraulic systems should innovations that will deliver benefits to the also be identified period. customers at the end. There is a need for development of competition among 6.12 Training of Technologists technology providers that will be a key There should be a plan for sustainable driver of future innovation – changing both training of technologists and their the amount and quality of research. The replacement. present system does not encourage research output. REFERENCES  It leads to starvation of interest. There is Adebara, S. A, Afolayan, A., Omajali D. I. no motivation for sustained research and Olatunji, A. A. (2016). outputs “Assessment of The Effects of Solid  Researchers should share in the benefits Waste Dumpsite on Groundwater in accruing from their research efforts. For Osogbo And Ede Metropolis Osun instance, companies or individuals that State, Nigeria” International Journal innovate something new could be of Engineering Technologies and encouraged by giving them incentives. Management Research, 3(2):1-21. Adedokun, T.A. and Agunwamba, J.C. 6.9 Pollution Monitoring (2014). Analysis of Pollution of River A mechanism to monitor pollution of Challawa by Industrial Effluents. Int. streams by enforcing effluent quality J. on Recent and Innovation Trends in standards and constantly ensuring public

24 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Computing and Communication, plants and microorganism. Int. J. 2(7): 1821 – 1826. Current Sc. 6: 153 -160. Adewumi, J.R. and Oguntuase, A.M. 2016. Agunwamba, J.C., Ukpai, O.K. and Planning of Waste Water Reuse Onyebuenyi, I.C. (1998). Solid waste Programme in in Nigeria. management in Onitsha. Waste Consilience: The Journal of Management and Research 16(1), 23- Sustainable Dev. 15(1): 1-33 31. Agunwamba, J.C and Udedeh, E. (2009). Ahmad, M.T. (2016). The role of water Solid Waste Management by Public vendors in water service delivery in and Private Sector Operators in Port developing countries: A case of Dala Harcourt, Nigeria. International J. of Local Government, Kano, Nigeria. Environmental Issues, 6(1 & 2): 190 – Applied Water Science, 7(3): 1191- 203. 1201. Agunwamba, J.C. (1994). Rural water supply: Akinbile, C. O. (2012). Environmental Impact success and failures. In Rural Dev. In of Landfill on Groundwater Quality Nigeria: Concepts processes and and Agricultural Soils in Nigeria. Soil prospects (E.C. Eboh et. al., Ed.) Auto and Water Resource, 7(1): 18 - 26. Century Publishing Co. Ltd. 103-118. Ayalew, M; et al. (2014). Small Independent Agunwamba, J.C. (2002). Verification of some Water Providers: Their Position in the design equations and determination Regulatory Framework for the of reaction coefficients for waste Supply of Water in Kenya and stabilization ponds in Southeastern Ethiopia. Journal of Environmental Nigeria. J. Applied Sci. and Tech. 2(1): Law, 26(1), 105–128, 1 – 6. Bichi, M.H., Agunwamba, J.C. and Muyibi, Agunwamba, J.C. (2003). Analysis of S.A. (2012). Optimization of scavengers’ activities and recycling in Operating Conditions for the some cities of Nigeria. application of Moringa oleifera Environmental Management, 32(1): (Zogale) seeds extract in water 116 – 127. disinfection using response surface Agunwamba, J.C. (2003). Waste engineering methodology. A.J. of Biotechn. 11(92), and management tool. Immaculate 15875 – 15887. Publications Ltd. Enugu. Bogoro, S.E. 2014. Institutionalizaion of Agunwamba, J.C. and Eze, G.N. Analysis of research and development (R and D) the quality and health impacts of as the launch pad for Nigeria’s sachet water. Nigerian J. of Industrial technological Revolution. Invited and Systems Studies,4(2) 28 – 34. paper presented at 62nd University of Agunwamba, J.C. and Nnadi, J.C. (2009). Ibadan Interdisciplinary Research Kinetics of Bioremediation of Crude Discourse, Main Hall Conference Oil Polluted Soil. Nigerian Journal of Centre, University of Ibadan. Engineering Research and Dada, A.C. (2009). Sachet water phenomenon Development, 8(3): 18 – 28. in Nigeria: Assessment of the Agunwamba, J.C., Onyekweredike, Kelechi, potential health impacts. African O. and Mmonwuba, N. (2013). Journal of Microbiology Research, Comparative analysis of 3(1): 15-21. bioremediation of heavy metals using Dan ‘a zumi, S. and Bichi, M.H. (2009). Industrial pollution and implication

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on source of water supply in Kano, near septic-tank soak away system Nigeria. Int. Journal of Engineering and pit latrine in Ife North Local and Technology. IJET-IJEWS, 10(1): Government Area of Osun State 101-110. Nigeria: Transnation Journal of Dirks, M. and Moeller, J. (2017). Fostering Science and Technology, 3(10): 8-21. innovation within water utilities. Ogarekpe, N.M. and Agunwamba, J.C. Water Research Foundation. (2015). A new model for the http://www.waterrf.org/pages/project performance of integrated solar and s.aspx?PID=4642. hydraulic jump enhanced Ekwule, R. (2018). Performance evaluation of stabilization pond. Desalination and a municipal water distribution Water Treatment, 57(27): 12778-12486. network using Watercad and Epanet Olanrewaju, O. (2017). 2017 Budget: Again, simulators. M.Engrg Project Report, Nigeria fails to meet UN benchmark University of Nigeria, Nsukka, on education. Premium Times. Nigeria. December 16. Eneh, O.C. and Agunwamba, J.C. 2011. https://www.premiumtimesng.com/n Managing Hazardous Wastes in ews/top-news/218097-2017-budget- Africa: Recyclability of Lead from E- nigeria-fails-meet-un-benchmark- waste materials. Journal of Applied education.htmls). Sciences, 11(7), 3215 – 3220. Opryszko, M.C., Huang, H., Soderlund, K., Schwab, K.J. (2009). Data gaps in FEPA, (1991). “Guidelines and Standards for evidence-based research on small Environmental Pollution Control in water enterprises in developing Nigeria,” Federal Environmental Go- countries. J. Water Health, 7(4): 609- vernment Protection Agency. 622. Godwin, G., Agunwamba, J.C. and Ugbebor, Owlia, M.B. and Mirzaei, M. (2014). J.N. (2015). Comparison of Noise Conducting research in developing Pressure Level from Flow Station, countries: A challenging issue. Multiple Noise Sources with Federal Journal of Case Reports in Practice Ministry of Environment Standard. J. (JCRP), 2(4): 98-99. of Env. Sci., Computer Sci. and Engr. Rick, T. (2014) Top 30+ key obstacles to and Tech. 4(3): 393 – 408. innovation. September 5, 2014 Hassan, A.S., Hayatu, J.M. and Mohammed, https://www.torbenrick.eu/blog/strate I.U.(2016).An Overview of Water gy/30-key-obstacles-to-innovation/ Supply Infrastructural Challenges in Sheshe, M.U. and Magashi, A.M. (2014). Nigeria: A Case Study of Taraba Assessment of physicochemical State. 13(1), 46-51 quality of sachet water produced in Henley, W. (2013). The new water selected local government areas of technologies that could save the Kano metropolis, Kano State, Nigeria. planet. https://www.the Bayero J. Pure Appl. Sci. 7(2): 31-35. guardian.com/Sustainable.business/n Speight, V.L. (2017). Innovation in the water ew-water technologies. Mon. 22 July, industry: barriers and opportunities 17 ; 41 for US and UK utilities. https:// Jeje, J.O. and Oladepo, K.T. (2013). onlinelibrary.wiley.com/doi/full/10.10 Microbiological quality of water 02/wat2.1082#wat 21082. collect from unlined wells located

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Tariwari C. N. Angaye and Jasper F. N. Journal of Engineering Inventions, Abowei. (2017). Review on the 6(2) 1–12. Environmental Impacts of Municipal Vose, P.B. and Cervellii, A. (1981). Problems Solid Waste in Nigeria: Challenges of scientific research in developing and Prospects Greener Journal of countries. IAEA Bulletin, 25(2): 37-40. Environment Management and (2017). EPA United States Environmental Public 6 (2), 018-033. Protection Agency. Udeh, N.U. and Agunwamba, J.C. (2017). (2005). Oslo, manual: Guidelines for Removal of heavy metals from collecting and interpreting Aqueous solution using Bamboo innovation. Data, 3rd Edition, 162 pp. based activated carbon. International OECED Publishing, European Commission.

Innovation Solution in Engineering (ISIE) 27 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Reservoir Sedimentation Modelling and Prediction of Project Lifetime

C. C. Mbajiorgu Eco-Hydrological Systems Research Unit (EHSRU) Department of Agricultural & Bioresources Engineering University of Nigeria, Nsukka [email protected]

ABSTRACT Sedimentation causes an estimated annual reduction of 1 percent in the total capacity of all reservoirs worldwide, the figure rising to as much as 30 percent regionally. Sediments also block intakes in reservoirs and damage tunnels and turbines. The use of models to simulate reservoir sedimentation enables the key parameters of reservoir life to be predicted over the long term. In particular, they can provide information on the distribution of sediments within a reservoir; a key issue for the project’s lifetime and the planning of management measures. The rate of reservoir sedimentation depends mainly on the size of a reservoir relative to the amount of sediment flowing into it: a small reservoir on an extremely muddy river will rapidly lose capacity; a large reservoir on a very clear river may take centuries to lose an appreciable amount of storage. To predict sedimentation rate with reasonable accuracy involves the estimation of trap efficiency of a reservoir. Different methods of estimation of the reservoir trap efficiency are discussed. The Generalized Sediment Transport Model for Alluvial River Simulation, version 3 (GSTARS3), which simulates and predicts sedimentation processes in lakes and reservoirs is presented. GSTARS is a series of computer models developed by the U.S. Bureau of Reclamation. The stream tube concept is used to solve one-dimensional equations for each stream tube independently and obtain semi-two-dimensional variation of the hydraulic conditions along and across stream tubes for rivers and reservoirs. Sediment transport, scour, and deposition processes are simulated along each stream tube independently to give a semi-three-dimensional variation of the bed geometry. GSTARS models apply the theory of minimum stream power to the determination of optimum channel width and channel geometry. The concepts of channel side stability, and active, inactive, and armoring layers are used in all GSTARS models for realistic long-term simulation and prediction of the scour and deposition processes in rivers and reservoirs. Similarly, an EXCEL programme (SED-RES) to compute the sedimentation in a reservoir for given sediment transport and characteristics at the upstream reservoir boundary is discussed, with an example application to illustrate. In addition, a mass balance differential equation for reservoir sedimentation is formulated for numerical solution. Based on a simplified consideration for the rate of sedimentation in a reservoir, a closed form solution of the differential equation is derived for application in the prediction of project lifetime. Methods and approaches for sediment removal from reservoirs such as sluicing, venting and flushing, as well as for reducing reservoir sedimentation in general, are briefly reviewed.

Keywords: Reservoir Sedimentation, Modelling, Project Lifetime, GSTARS, SED-RES, Sluicing, Venting and Flushing of sediments, Watershed Management.

1. INTRODUCTION river’s total sediment load captured by a dam river, in effect, is a body of flowing – known as its "trap efficiency" – approaches sediments as much as one of flowing 100 per cent for many projects, especially A water. When a river is stilled behind those with large reservoirs. As the sediments a dam, the sediments it contains sink to the accumulate in the reservoir, so the dam bottom of the reservoir. The proportion of a gradually loses its ability to store water for

28 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 the purposes for which it was built. Every sediment carried by the world’s rivers. reservoir loses storage to sedimentation Sediment flows vary widely both annually although the rate at which this happens and seasonally over time – far more than varies widely. Despite more than six decades water flows – and so calculating an annual of research, sedimentation is still probably average needs a long run of data. As it is the most serious technical problem faced by with river flows, the variability of sediment the dam industry. yield is greatest in arid and semi–arid climates, where the data tends to be most The rate of reservoir sedimentation depends sparse. mainly on the size of a reservoir relative to the amount of sediment flowing into it: a The amount of sediment carried into a small reservoir on an extremely muddy river reservoir is at its highest during floods. In will rapidly lose capacity; a large reservoir some cases, half of a river’s annual sediment on a very clear river may take centuries to load may be transported during only 5 to 10 lose an appreciable amount of storage. Large days of flood flow. During and after a reservoirs in the US lose storage capacity at particularly violent storm a river may carry an average rate of around 0.2 per cent per as much sediment as it would in several year, with regional variations ranging from "normal" years. Mudslides caused by 0.5 per cent per year in the Pacific states to earthquakes and volcanoes can also have a just 0.1 per cent in reservoirs in the northeast. dramatic and unpredictable effect on Major reservoirs in China lose capacity at an reservoir sedimentation. Global warming, annual rate of 2.3 per cent (McCully, 1996). which is predicted to cause more intense storms, will likely increase both the Apart from rapidly filling their reservoirs, unpredictability and rate of reservoir sediment–filled rivers also cause headaches sedimentation. for dam operators due to the abrasion of turbines and other dam components. The Most modern dams are designed so that they efficiency of a turbine is largely dependent can afford to lose some storage capacity upon the hydraulic properties of its blades, without their performance being impaired – just as an aeroplane depends on the the part of a reservoir known as "dead aerodynamic properties of its wings. The storage" which lies beneath the elevation of erosion and cracking of the tips of turbine the dam’s lowest outlet. However, sediments blades by water–borne sand and silt do not build up evenly along a horizontal considerably reduces their generating plane, so that some "live storage" is usually efficiency and can require expensive repairs. lost long before the dead storage is filled.

To make a meaningful economic forecast for a planned dam, it is necessary to be able to predict its sedimentation rate with reasonable accuracy. However, it is extremely difficult to estimate how much sediment will be trapped by a reservoir. Collecting data on sediment discharge is even more expensive and difficult than gathering stream flow data, and so there is little reliable information available on the

Innovation Solution in Engineering (ISIE) 29 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Figure 1: Overview of Kangimi Dam Reservoir, no choice but to clear land further up the Kaduna State, Nigeria valley or hillside. In any case, deforestation

and soil erosion are both increasing rapidly The actual process of sediment deposition is in Nigeria and around the world, and it unique to every reservoir and is impossible should be assumed when dams are built that to predict accurately. In general, the coarser, soil erosion in their watershed will increase heavier sediments, the gravel and sand, tend over the projected economic life of the to settle out at the upper end of reservoir, reservoir. forming a "backwater" delta which gradually advances toward the dam. The lighter 2. A GENERALIZED SEDIMENT sediments, the silt and clay, tend to be TRANSPORT MODEL FOR deposited near the dam. ALLUVIAL RIVERSIMULATION (GSTARS) Watershed management – including GSTARS is a series of computer models afforestation and the promotion of farming developed by the U.S. Bureau of practices which reduce soil erosion – is Reclamation. The stream tube concept is used frequently advocated as the best way of in all GSTARS models which allow the cutting sediment deposition in reservoirs. solution of one-dimensional equations for While these schemes may be recommended each stream tube independently to obtain in project plans, they are rarely implemented; semi-two-dimensional variation of the dam agencies are usually more interested in hydraulic conditions along and across stream building dams than planting trees and tubes for rivers and reservoirs. Sediment digging field terraces. transport, scour, and deposition processes are simulated along each stream tube independently to give a semi-three- dimensional variation of the bed geometry. Most sediment transport computer models assume that channel width is given and cannot change during the simulation process. GSTARS models apply the theory of minimum stream power to the determination of optimum channel width and channel geometry. The concepts of channel side stability, and active, inactive, and armoring layers are used in all GSTARS models for realistic long-term simulation and prediction of the scour and deposition processes in

Figure 2: General Pattern of Reservoir Sedimentation rivers and reservoirs. GSTARS models have been applied in many countries for solving a Overall, building a dam in a valley is much wide range of river and reservoir more likely to increase erosion than reduce it; sedimentation problems. dams open up remote areas to road–builders, developers, loggers, farmers and miners, The sediment concentration or load accelerating deforestation and soil loss. computed by a formula is the equilibrium When insufficient resettlement land is made sediment transport rate without scour or available, oustee farming families may have deposition. Natural rivers constantly adjust

30 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 their channel geometry, slope, and pattern in and density; water viscosity; and the response to changing hydrologic, hydraulic, chemical composition of the water and and geologic conditions and human activities sediment. The rate of flow through the to maintain dynamic equilibrium. To reservoir can be computed as the ratio of simulate and predict this type of dynamic reservoir storage capacity to the rate of flow. adjustment, a sediment routing model is The potential for reservoir sedimentation and needed. As presented above, GSTARS 2.1 associated problems can be estimated from model (Yang and Simoes, 2000) uses the the following six indicators: stream tube concept in conjunction with the  The reservoir storage capacity (at the theory of minimum energy dissipation rate, normal pool elevation) relative to the or its simplified theory of minimum stream mean annual volume of riverflow. power, to simulate and predict the dynamic  The average and maximum width of the adjustments of channel geometry and profile reservoir relative to the average and in a semi-three-dimensional manner. maximum width of the upstream river channel. The amount of reservoir sedimentation over  The average and maximum depth of the the life of the project needs to be predicted reservoir relative to the average and before the project is built. If the sediment maximum depth of the upstream river inflow is large relative to the reservoir channel. storage capacity, then the useful life of the  The purposes for which the dam and reservoir may be very short. GSTARS3 (Yang reservoir are to be constructed and how and Simoes, 2002) is an enhanced version of the reservoir will be operated (e.g., GSTARS 2.1 to simulate and predict the normally full, frequently drawn down, sedimentation processes in lakes and or normally empty). reservoirs. It can simulate and predict the  The reservoir storage capacity relative to formation and development of deltas, the mean annual sediment load of the sedimentation consolidation, and changes of inflowing rivers. reservoir bed profiles as a result of sediment  The concentration of contaminants and inflow in conjunction with reservoir heavy metals being supplied from the operation. upstream watershed.

3. RESERVOIR SEDIMENT TRAP The ratio of the reservoir capacity to the EFFICIENCY mean annual streamflow volume can be used Because of the very low velocities in as an index to estimate the reservoir reservoirs, they tend to be very efficient sediment trap efficiency. A greater relative sediment traps. The amount of sediment reservoir size yields a greater potential deposited within a reservoir depends on the sediment trap efficiency and reservoir trap efficiency. Reservoir trap efficiency is sedimentation. the ratio of the deposited sediment to the total sediment inflow and depends primarily Churchill (1948) developed a trap efficiency upon the fall velocity of the various sediment curve for settling basins, small reservoirs, particles, flow rate and velocity through the flood retarding structures, semi-dry reservoir (Strand and Pemberton, 1982), as reservoirs, and reservoirs that are frequently well as the size, depth, shape, and operation sluiced. Using data from Tennessee Valley rules of the reservoir. The particle fall Authority reservoirs, Churchill (1948) velocity is a function of particle size, shape, developed a relationship between the percent

Innovation Solution in Engineering (ISIE) 31 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 of incoming sediment passing through a average annual inflow, then the sediment reservoir and the sedimentation index of the trap efficiency would be near zero. reservoir (Figure 3). The sedimentation index is defined as the ratio of the period of retention to the mean velocity through the reservoir. The Churchill curve has been converted to a dimensionless expression by multiplying the sedimentation index by g, acceleration due to gravity.

Figure 4a: Trap efficiency related to capacity/annual inflow ratio (Brune, 1953)

Figure 3: Churchill's (1948) curves for local and upstream sediment, relating TE to sedimentation index

Brune (1953) developed an empirical relationship for estimating the long-term reservoir trap efficiency for large storage or Figure 4b: Trap efficiency related to capacity/annual normal pond reservoir based on the inflow ratio correlation between the relative reservoir size Trimble and Carey (1990) compared both the and the trap efficiency observed in Tennessee Churchill curves (1948) and the Brune curves Valley Authority reservoirs in the (1953) for 27 reservoirs in the Tennessee southeastern United States (see Figure 4a). River Basin. They estimated the sediment Using this relationship, reservoirs with the yield based on the two TE curves and capacity to store more than 10 percent of the sediment accumulation data for these average annual inflow would be expected to reservoirs. The estimated TE values from trap between 75 and 100 percent of the Brune’s curves were estimated to be equal to inflowing sediment. Reservoirs with the or higher than the TE values from Churchill’s capacity to store 1 percent of the average curves. annual inflow would be expected to trap between 30 and 55 percent of the inflowing The width and depth of the reservoir, sediment. When the reservoir storage relative to the width and depth of the capacity is less than 0.1 percent of the

32 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 upstream river channel, can also serve as the estimated sediment inflow to a reservoir indicators of reservoir sedimentation. Even if has been established, attention must be given the reservoir capacity is small, relative to the to the effect the deposition of this sediment mean annual inflow, a deep or wide will have upon the life and daily operation of reservoir may still trap some sediment. The the reservoir (Strand and Pemberton, 1982). purposes for which a dam is constructed, The mean annual sediment inflow, the trap along with legal constraints and hydrology, efficiency of the reservoir, the ultimate determine how the reservoir pool will be density of the deposited sediment, and the operated. The operation of the reservoir pool distribution of the sediment within the will influence the sediment trap efficiency reservoir all must be considered in the design and the spatial distribution and unit weight of the dam. Usually, to prevent premature of sediments that settle within the reservoir. loss of usable storage capacity, an additional The reservoir trap efficiency of a given volume of storage equal to the anticipated reservoir will be greatest if substantial sediment deposition during the life of the portions of the inflows are stored during reservoir is included in the original design. floods when the sediment concentrations are highest. If the reservoir is normally kept full Based on analysis of reservoir sedimentation (run of the river operation), flood flows pass data in the USA, Borland and Miller (1960) through the reservoir and sediment trap distinguished four types of reservoirs. The efficiency is reduced. Coarse sediments data indicated that a definite relationship would deposit as a delta at the far upstream exists between the reservoir shape and the end of the reservoir. When reservoirs are percentage of sediment deposited at various frequently drawn down, a portion of the depths throughout the reservoir. The type of reservoir sediments will be eroded and reservoir can be related to the reciprocal transported further downstream. Any clay- value (M) of the slope of the line obtained by sized sediments that are exposed above the plotting reservoir depth as ordinate and reservoir level will compact as they dry out reservoir capacity as abscissa on log-log (Strand and Pemberton, 1982). scale. The four standard types are (see Figure 5): Once sediment capacity is reached, the entire • lake type I; M= 3.5-4.5; greater portion of sediment load supplied by the upstream the sediment is deposited in the upper river channel is passed through the part of the reservoir; remaining reservoir. For example, the pool • flood plain-foot hill type II; M= 2.5-3.5; behind a diversion dam is typically filled • hill type III; M= 1.5-2.5; with sediment within the first year or two of • gorge type IV; M=1-1.5; greater portion of operation. For a large reservoir like Lake the sediment is deposited in the deeper Powell, the average annual sediment inflow part (dead storage zone) of the is 0.1 percent of the reservoir storage reservoir. capacity. If contaminants and heavy metals are transported into a reservoir, they will These types of standard curves were found likely settle with the sediments in the to be valid for most reservoirs in India reservoir. This may improve the water (Murthy, 1977). quality of the downstream river, but the water quality in the reservoir may degrade To compute the trap efficiency, a method over time as the concentrations of developed by Borland (1971) uses the contaminants and metals accumulate. Once fraction of material and the settling velocity:

Innovation Solution in Engineering (ISIE) 33 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

(1) From equations (3) and (4), the mass balance equation can be formulated as: Where: TE = Trap efficiency; L = total length ∂As/∂t - Qs,o(ρb(1-p))-1∂E/∂x = 0 (5) of the reservoir; w = fall velocity of the sediment; V = mean velocity of flow; and h = flow depth. Julien (1998) also developed a Equation (5) can be solved numerically to trap efficiency equation, which is defined as determine the sedimentation along the the percentage of sediment fraction i that length of the reservoir. The water level settles within a given distance X: should be constant during each time step. The distribution of the sediment deposits (2) along the cross-section can be assumed to be

constant or proportional to the water depth Where: TE = Trap efficiency; X = total length of the cross-section. of the reservoir; ω = fall velocity of the sediment; V = mean velocity of flow; and h = 4.1 AN EXAMPLE RESERVOIR flow depth. SEDIMENTATION MODEL

APPLICATION Calculations of sediment-filling rates in reservoirs typically involve computation for successive time intervals:  storage at beginning of interval, find C/I ratio;  trap efficiency;  accumulated sediments;  new storage at end of the interval.

Figure 5: Types of reservoir according to Borland HR Wallingford (1983) applied an EXCEL and Miller (1960) programme (SED-RES) to compute the

sedimentation in a reservoir for given 4. MODELLING sediment transport and sediment Based on the mass balance of sediments, the characteristics at the upstream reservoir sedimentation along a reservoir can be boundary (x = 0 m). Three sediment fractions determined from the following equation: are considered: ∂As/∂t + (ρb(1-p))-1∂Qs/∂x = 0 (3) - clay with settling velocity ws,clay = 0.0001 m/s (input value), Where: As = bas = sedimentation area of cross- - silt with settling velocity ws,silt = 0.001 m/s section; b = width of cross-section, as = sedimentation thickness; t = time; p = (input value), - sand with settling velocity ws,sand = 0.01 porosity factor; ρb = dry bulk density of 3 m/s (input value). deposited sediment (kg/m ); Qs = sediment transport (in kg/s) at cross-section x; and x = longitudinal coordinate. The sediment The reservoir is schematized into five transport at section x can be related to the sections (or compartments) A, B, C, D and E, upstream sediment transport by: each with length L, width W and depth do = h Qs = (1-E)Qs,o (4) – ho = depth below line through bed level at x = 0 m, h = flow depth, ho = flow depth at x = 0 Where: E = trapping efficiency at section x, m. The total storage V = Σ(LiWi(hi – ho)). Qs,o = incoming sediment transport at x = 0.

34 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Rijn (2013) reported the application of SED- Measured sedimentation values are also RES model to the sedimentation of the given in Table 1. The initial storage volume Kindaruma reservoir in Kenya. This reservoir was about 12.2 x 106 m3 in 1968. As measured in the Tana River was opened in 1968. In sediment concentrations upstream of the 1974 a new reservoir was opened just reservoir were not available, the clay, silt and upstream of the Kindaruma reservoir, sand concentrations were estimated to give thereby reducing the sediment input of the an overall sedimentation volume of the right Kindaruma reservoir after 1974 to almost order of magnitude (about 6.5 x 106 m3 in six zero. Measured sedimentation values were years), resulting in cclay = 0.175 kg/m3, csilt = 0.1 available for the period of 1968 to 1974 based kg/m3 and csand = 0.025 kg/m3. The clay on bottom sounding surveys. The Tana River fraction is assumed to be about twice as large is the largest river in Kenya and has a mean as the silt concentration. The input annual discharge of about 100 m3/s in the concentrations were kept constant in all period 1968 to 1974. The width of the river computations. The Chézy-coefficient used to just upstream of the reservoir is about 70 m. compute the bed-shear velocity (u* = ug0.5 /C) The mean flow depth was assumed to be in each section of the reservoir was assumed about ho = 3 m. The reservoir was to be 70 m0.5/s. schematized into 5 sections (see Table 1).

Table 1: Characteristics of Kindaruma reservoir in Kenya, Africa Section Length Width Initial depth Initial storage Measured Measured layer L W d=h-ho volume sedimentation thickness after 6 (m) (m) (m) V volume after 6 years (m3) years (m) (m3) A 1050 170 8.2 1.46 106 1.2 106 6.8 B 950 300 8.5 2.42 106 1.9 106 6.8 C 550 415 4.5 1.03 106 0.5 106 2.2 D 1350 245 10 3.3.1 106 1.4 106 4.2 E 1000 340 11.7 3.98 106 1.5 106 4.4 Total 4900 12.2 106 6.5 106

The sedimentation results based on the three According to the other methods, only Section trap efficiency methods used (Avr = 0.25, Aev = A is filled up with sediments. 0.06, Ab = 1.055; bulk density according to formula) are given in Table 2. These results The influence of the bulk density on the show that the three methods used give sedimentation results is shown in Table 3. A similar sedimentation volumes in the range constant bulk density of 0.8 ±0.2 t/m3 results of 5.4 to 6.6 106 m3 in 6 years. The overall trap in a variation of about 25% in the efficiency values (defined as total sedimentation volumes. A variable bulk sedimentation volume/total sediment influx) density based on the percentages of clay, silt were respectively 100%, 98% and 86% for the and sand (including consolidation factor) methods of Van Rijn, Eysink-Vermaas and resulted in a slightly smaller sedimentation Borland. According to the method of Van volume (5%; see Table 3) than based on a Rijn, the storage volumes of Section A, B and constant bulk density of 0.8 t/m3. C were completely filled up with sediments.

Innovation Solution in Engineering (ISIE) 35 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Table 2: Computed and measured sedimentation volume and layer thickness for Kindaruma reservoir in Kenya, Africa Section Sed. Volume (m3) Sed. Layer thickness (m) Van Rijn Eysink- Borland Measured Van Rijn Eysink- Borland Measured Avr=0.25 Vermaas Ab=1.055 after 6 yrs Avr=0.25 Vermaas Ab=1.055 after 6 yrs Aev=0.06 Aev=0.06 A 1.49 106 1.48 106 1.61 106 1.2 106 8.36 8.31 9.01 6.8 B 2.49 106 2.16 106 1.60 106 1.9 106 8.73 7.59 5.60 6.8 C 1.10 106 0.91 106 0.77 106 0.5 106 4.80 3.98 3.35 2.2 D 1.22 106 0.89 106 0.83 106 1.4 106 3.67 2.69 2.51 4.2 E 0.28 106 0.58 106 0.60 106 1.5 106 0.82 1.71 1.77 4.4 Total 6.58 106 6.02 106 5.40 106 6.5 106

Table 3: Influence of bulk density on computed sedimentation volume and layer thickness for Kindaruma reservoir in Kenya, Africa (Method of Van Rijn) Section Sed. Volume (m3) Sed. Layer thickness (m) ρb=0.8 ρb=0.6 ρb=1.0 ρb= ρb=0.8 (t/m3) ρb=0.6 ρb=1.0 ρb= (t/m3) (t/m3) (t/m3) variable (t/m3) (t/m3) variable (t/m3) (t/m3) A 1.56 106 1.59 106 1.54 106 1.49 106 8.76 8.91 8.65 8.36 B 2.60 106 2.68 106 2.55 106 2.49 106 9.12 9.39 8.95 8.73 C 1.20 106 1.15 106 0.87 106 1.10 106 5.26 5.04 3.83 4.80 D 1.35 106 3.18 106 0.50 106 1.21 106 4.07 9.63 1.52 3.66 E 0.24 106 0.61 106 0.11 106 0.28 106 0.71 1.80 0.32 0.82 Total 6.95 106 9.21 106 5.57 106 6.57 106

5. PREDICTION OF PROJECT LIFE TIME which varies from 0.0021 to 0.0001 for coarse The rate of sedimentation in a reservoir can and fine materials respectively. For medium be expressed as, sized sediment, K = 0.00021. In equation (6), the negative sign indicates that reservoir (6) capacity decreases with time due to sedimentation. By combining equations (6) Where: G = weight of annual sediment and (7) a solution is obtained as follows: inflow; C = capacity of reservoir; t = time; ȳ = average specific weight of sediment deposits (8) and E = trap efficiency of the reservoir, defined as the ratio of weight of sediments Integrating both sides of equation (8), retained in the reservoir annually to the total weight of annual inflow of sediments. Trap efficiency is given as, or (7) (9)

Where: C = capacity of the reservoir, m3; A = area of the catchment drained by the Where B is an integration constant. At time t dammed river, km2 and K = a coefficient = 0, reservoir capacity C = Co = initial

36 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 capacity. Substituting these conditions into • Raising of the ground-water table in equation (9), backwater region; • The worsening of navigation conditions (10) in the reservoir basin (reduction of clearance under bridges in backwater Therefore, the reservoir sedimentation region); equation can be written as: • Changing the water quality near the dam; (11) • Influencing the stability of the stream channel downstream of the dam; By the time a reservoir has lost half of its • Changing the stream ecology in the dam initial capacity to sedimentation, it may need region; and either to be replaced, dredged, or • Causing other environmental impacts by supplemented by an additional storage changing the water quality. facility. Using this criterion to define the useful life of a reservoir, equation (11) can be The loss of storage volume of the reservoir used to calculate the time in years when C = may cause severe problems as the primary 0.5C0, i.e. the useful life of the reservoir. function of most reservoirs is to store water for flood control, water supply, irrigation 6. METHODS OF RESERVOIR and power. If the outlets are closed, the SEDIMENTS REMOVAL deposition of sediments in the reservoir will The most important impacts due to reservoir be maximum and the sediments will sedimentation are: eventually accumulate against the outlets. To • The reduction of useful and economic life remove the sediments as much as possible, of reservoirs by excessive, rapid or the outlets should be opened regularly when premature loss of storage capacity and the water level is high to exert sufficient the services that depend on it; pressure on the sediments deposited in the • The reduction of hydro-power outlet zone and to create a zone of generation, water supply or discharge concentrated erosion near the outlet (flushing regulation capacity, where the reservoir zone). To maintain the erosion process, the has been designed and completed to water level in the reservoir must be lowered. achieve these functions; Flushing operations should be performed • Causing difficulties in flood protection by regularly to minimize the deposition of bed aggradation, increasing flooding sediments near the outlets. It can also be level upstream of dam; tried to generate density or turbidity currents • The silting, choking and blocking of that carry the fine sediments to the deepest bottom outlets and intakes, worsening parts of the reservoir and through the outlets. the operation conditions for the hydro mechanical equipment at the dam; Appropriate measures for the release of • The abrasion and damage of tunnels, sediments from a reservoir are required to galleries, guiding slots and rails of gates, deal with excessive sedimentation. Dams turbines and other equipment at the dam should be constructed with adequate bottom and power station, due to the action of sluices for flushing of sediments. The high velocity, sediment overloaded hydraulic regime should be designed to flows; route the inflowing sediment through or • The additional lateral force on the dam around the storage section of the reservoir to wall exerted by deposited sediment; minimize deposition and to remobilize and flush out previously deposited sediments.

Innovation Solution in Engineering (ISIE) 37 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Adequate reservoir management is required a density current (movement of fluid- to reduce the sedimentation by means of sediment mixture by gravity under another various operational procedures. Sediment mixture of lower density) near the bed removal management is often in conflict with without drawdown of the water level in the short-term water-use management. Most reservoir; the ratio of sediment outflow and effective is to reduce the inflow of sediment sediment inflow (venting efficiency) should into the reservoir (by preventing soil erosion be as large as possible; values up to 0.5 have and landslides, etc). A review of sediment been observed in China (Fan and Morris, removal methods from reservoirs is 1992); favourable conditions are: narrow presented by White (2001), Brandt (2000) and reservoir and steep bed slopes, presence of Atkinson (1996). Fan and Morris (1992) have one main channel, large sediment inflow and reviewed the experiences on the control of large transport capacity, long duration of sedimentation in silt-laden rivers and flood events (larger than travel time of reservoirs in China. density current through reservoir), many low-level outlets, and correct timing of The following operations can be employed to opening and closing procedures (Figure 6); remove sediments from reservoirs: • Emptying and flushing of sediment; • Sluicing of sediment; routing of removal of previously deposited sediments; sediment through the reservoir during flood two types of operational methods are applied events (with high concentrations); water (1) under pressure: sudden release of water levels in the reservoir should be kept low and sediment through low-level outlets with (drawdown of water levels by opening of high water level in reservoir (no drawdown); multiple and multi-level bottom sluices in only a relatively small flushing cone will be dam); during rising water level of flood obtained; (2) free flow: erosion of sediment event, the outflow of sediment from the from bed in an almost empty reservoir (low reservoir is always smaller than the inflow of water level in reservoir) by the inflowing sediment into the reservoir; during falling water; when the original bottom gradient is water level, the outflow of sediment is larger approximately re-established, the operation than the inflow of sediment due to erosion of should be stopped as the transport capacity bed material from the reservoir; only a small will be greatly reduced and almost clear amount of runoff can be stored in the water will be flushed out; generally only reservoir during the falling limb of the flood sediment is removed from the old river event (relatively clear water); large multi- channel (flushing channel) and the banks on level outlet works are required over the both sides of the main channel are not width of the dam; favourable conditions are: eroded; additional measures are often narrow and short reservoir configuration, required for flushing of banks; bed erosion drawdown level below half dam height, river from the upper part of the reservoir is flow larger than two times mean annual flow generally small; flushing is efficient if both discharge (flow hydrograph should be retrogressive erosion of fine sediments predictable), many large low-level outlets, moving upstream the channel and sediment inflow should be mainly progressive erosion of coarse materials suspended sediments; experienced operators moving downstream can be established; required for correct timing of procedures; favourable conditions are: river inflow • Venting of sediment; routing of discharge should be greater than three times sediment through the reservoir in the form of the mean annual inflow discharge, narrow reservoir with steep bed slopes, many low-

38 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 level outlets (water levels should as low as possible), regular operation (at least yearly) to prevent consolidation of bed materials and negative downstream effects; start at beginning of flood events (Figure 7); • Dredging of sediment for small-scale reservoirs in situations with frequent shortage of water; sediment disposal is performed by siphoning through pipelines over the dam.

All hydraulic methods to remove sediments Figure 7: Flushing the Sanmenxia dam on the main from a reservoir require that water is stream of the Yellow River released from the reservoir to transport sediments and all methods (except venting) 7. REDUCING RESERVOIR also require a substantial or full drawdown SEDIMENTATION of the reservoir. Therefore, flushing is not There are several methods available for efficient for reservoir operation because the reducing reservoir sedimentation. These reservoir has to be emptied and it requires methods relate to the reservoir location and large volumes of water passing through the size, land use practices in the upstream dam. Furthermore, the reservoir should be watershed, and special considerations for the rather narrow with relatively steep bed operation of the reservoir. In some cases, slopes and steep valley side slopes. It is also reservoirs can be operated for long-term easier to keep sediments in suspension sustainable use so that sedimentation (sluicing) than to remove them after eventually fills the reservoir. Extensive settlement and consolidation (flushing). An literature exists on the subject of reservoir overview of sites with successful flushing sedimentation. A reservoir sedimentation operations has been given by Atkinson handbook by Morris and Fan (1998) is an (1996). excellent reference and provides an extensive

list of other references. Qamar et al (2012) summarize the strategies for dealing with reservoir sedimentation as shown in Figure 8 below.

Figure 6: Schematic illustration of a venting operation

Innovation Solution in Engineering (ISIE) 39 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Figure 8: Schematic diagram of strategies for reservoir sedimentation management

REFERENCES Colorado, United States Bureau of Atkinson, E., 1996. The feasibility of flushing Reclamation, p.139-140 sediment from reservoirs. Report Di Silvio, G., 2001. Basic classification of OD137, HR Wallingford, Wallingford, reservoirs according to relevant UK. sedimentation processes, p. 285-293. Borland, W.M., 1971. Reservoir 29th IAHR, Beijing, China sedimentation, Chapter 29 in River Eysink, W. and Vermaas, H., 1981. Simple Mechanics, Water Resources methods for determination of Publications, Fort Collins, USA sedimentation in dredged channels Borland, W.M. and Miller, C.R., 1960. and harbour basins (in Dutch). Report Distribution of sediment in large S151, Delft Hydraulics, Delft, The reservoirs. Paper No. 3019, ASCE, Netherlands Transactions, Vol. 125, p. 166-180 Fan, J. and Morris, G.L., 1992. Reservoir Brandt, S.A., 2000. A review of reservoir sedimentation,I: Delta and density desiltation. Intern Journal of current deposits. Journal of Hydraulic Sediment Research, Vol. 15, No. 3, pp. Engineering, Vol. 118, No 3, p. 354- 321-342 369 Brune, G.M., 1953. Trap efficiency of Fan, J. and Morris, G.L., 1992. Reservoir reservoirs. Trans. American sedimentation, II: Reservoir Geophysical Union, Vol. 34., No. 3, desiltation and long-term storage Washington, D.C., USA, p. 407-418 capacity, Journal of Hydraulic Collell, M.R., 2012. Modelling Reservoir Engineering, Vol. 118, No 3, p. 370- Sedimentation. Innovation and 384. Research Focus, No.91, November HR Wallingford, 1983. Sedimentation in 2012 reservoirs; Tana river basin, Kenya. Churchill, M.A., 1948. Discussion of analysis Report No. OD 46, Wallingford, UK. and use of reservoir sedimentation Julien, P. Y., 1998. Erosion and data. Proc. of Federal Interagency sedimentation. Cambridge University Sedimentation Conference, Denver, Press, Cambridge, New York.

40 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Lane, E.W. and Koelzer, V.A., 1943. Density sedimentation control, p. 77-82. 29th of sediments deposited in reservoirs. IAHR, Beijing, China Report No. 9, St. Paul U.S. Engineer, Sloff, C.J., 1991. Reservoir sedimentation in District Sub-Office, Univ. of Iowa, reservoirs; literature review. Report USA No. 91-2, Civil Engineering Lara, J.M. and Pemberton, E.L., 1963. Initial Department, Delft University of unit-weight of deposited sediments, Technology, Delft, The Netherlands Paper No. 28, Proc. Federal Inter- Strand, R.I., and Pemberton, E.L., 1982. Agency Sedimentation Conference, Reservoir Sedimentation Technical U.S.D.A., USA Guidelines for Bureau of McCully, P., 1996. Silenced Rivers: The Reclamation, U.S. Bureau of Ecology and Politics of Large Dams. Reclamation, Denver, Colorado, 48 Zed Books, London. pp. Miller, C.R., 1953. Determination of the unit Trimble, S.W. and Carey, W.P., 1990. A weight of sediment for use in comparison of the Brune and sediment volume computations. U.S. Churchill methods for computing Bureau of Reclamation, USA. sediment yields applied to a reservoir Morris, G.L. and Fan, J.,1998. Reservoir system. USGS Water Supply Paper Sedimentation Handbook, 2340, 195-202. McGrawHill Book Co., New York. White, R., 2001. Evacuation of sediments Murthy, B.N., 1977. Life of Reservoir, from reservoirs. Thomas Telford, Technical Report No. 19. Central London Board of Irrigation and Power, New Yang, C.T., and F.J.M. Simoes (2000). User's Delhi, India Manual for GSTARS 2.1 (Generalized Qamar, M. Z., Verma, M.K., Meshram, A.P. Stream Tube model for Alluvial River and Pawar, M.K., 2012. Review of Simulation Version 2. I), U.S. Bureau Sediment Control Measures in of Reclamation, Technical Service Reservoirs; India Water Week 2012 – Center, Denver, Colorado. Water, Energy and Food Security : Yang, C.T., and F.J.M. Simoes (2002). User's Call for Solutions, 10-14 April 2012, Manual for GSTARS3 (Generalized New Delhi Sediment Transport model for Rijn, van L.C. (2013). www.leovanrijn- Alluvial River Simulation Version 3), sediment.com U.S. Bureau of Reclamation, Technical Siyam, A.M., Yeoh, J.S. and Loveless, J.H., Service Center, Denver, Colorado 2001. Sustainable reservoir .

Innovation Solution in Engineering (ISIE) 41 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

PREDICTION OF THE ONSET OF PAIN THRESHOLD IN SICKLE CELL DISEASE

E.E. Alagbe1, C. Solebo2 and A.A. Susu3 1Department of Chemical & Polymer Engineering, Lagos State University, Epe, Lagos State, Nigeria 2Research & Innovation Office, Office of the Deputy Vice-Chancellor (Academics and Research), University of Lagos, Lagos, Nigeria 3Department of Chemical & Petroleum Engineering, University of Lagos, Lagos, Nigeria Corresponding author ([email protected])

ABSTRACT Pain is a major characteristic feature of sickle cell disease (SCD) and acute pain crisis is the major cause of hospitalization and readmission of sickle cell patients. Previous studies found excellent correlation between the red blood cell (RBC) deformability index and dense cell density. Patients with high RBC deformability index experience more crises and crisis days than those with low RBC deformability. However, patients with a high percentage of dense cells had a relatively mild disease. These two indicators can be used as markers for pain onset in sickle cell patients. Regarding kinetic models, previous works have obtained the rate of reaction through homogeneous and/or heterogeneous nucleation mechanism, containing parameters that are not easily determined. In this study, the focus is on the development of a theoretical prediction of the onset of the pain threshold in sickle cell disease. We developed a new model to characterize the polymerization of Hb SS reaction leading to vaso-occlusion responsible for pain episodes. The new kinetic model utilizes the sigmoidal progress of the reaction in a two-step scheme that is devoid of detail mechanistic considerations, thus, yielding global rate expression for the polymerization reaction. In addition, a model for the hydrodynamics of blood flow was developed. Together, these two models provide equations for determining the rate constants for the residual reaction (k1), the autocatalytic reaction (k2), the delay time (tD), and in particular, time required before the onset of SCD (t1/2) through a MATLAB programing algorithm. The models presented here should facilitate the prediction of the onset of pain threshold thereby aiding the search for a threshold pain alert system.

Keyword: Sickle cell disease (SCD); Vaso-occlusion; Autocatalysis; Hydrodynamics of blood flow; Onset of pain threshold

1.0 INTRODUCTION vaso-occlusion is the most important ain is the critical manifestation of pathophysiologic event in SCD and explains sickle cell disease (SCD) and acute most of its clinical manifestation (Embury et P pain crisis is the major cause of al., 1994; Serjeant et al., 2002; Boros et al., hospitalization of sickle cell patients. One of 1976; Powars et al., 1978). Tissue damage due the major factors responsible for the painful to vaso-occlusion initiates a variety of episodes is vaso-occlusion (see Table 1) as complex biochemical, neurologic, and vaso-occlusion is a pre-requisite for the electrochemical sequence of events, development of acute sickle cell pain (Ballas, collectively referred to as nociception, that 2007). Tissue damage due to vaso-occlusion culminate in the perception of acute pain, releases numerous inflammatory mediators which, in turn, may become chronic in that initiate the transmission of painful nature. Vaso-occlusion is also responsible for stimuli and the perception of pain. Sickle cell creating a state of chronic vascular

42 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 inflammation that explains many features of painful crisis, Hb F must be very high, SCD (Kaul and Hebbel, 2000; Platt, 2000). usually above 20% of total hemoglobin (Ballas and Mohandas, 2004; Kaul and Table 1: Factors that culminate in vaso- Hebbel, 2000). Nevertheless, there are occlusion in patients with sickle patients with sickle cell anemia and low Hb F cell disease (Ballas, 2007) level (<10%) who have mild disease Factors intrinsic to red Factors extrinsic to red indicating that there must be other blood cells (RBCs) blood cells (RBCs) parameters of clinical severity. The coexistence of α thalassemia with sickle cell Sickle haemoglobin Whole blood viscosity anemia has a beneficial effect on the anemia polymerization White blood cell factors itself and may also influence the incidence of

other clinical features of the disease (Platt, Rheology of sickle Endothelial factors RBCs (i) Adhesion of sickle 2000; Fields, 1987; Cousins and Bonica, 1989). (i) Cellular RBCs to dehydration endothelium The acute sickle cell painful crisis is (ii) RBC deformability (ii) Intimal unpredictable in nature and may be and mechanical hyperplasia precipitated by known or unknown risk frigidity Hemostatic factors factors and triggers (Fabry et al., 1994; Ballas, Vascular factors et al., 1988). Patients with sickle cell anemia

and relatively high hemoglobin (Hb) level, The clinical picture of sickle cell anemia is for example, are more likely to experience highly heterogeneous and varies from very more frequent painful episodes than those mild to very severe. There is no simple patients with sickle cell anemia and lower relationship between clinical presentation Hb level. Stress of any kind, traumatic, and the degree of anemia in sickle cell physical, psychologic, physiologic, etc., may (Embury et al., 1994; Embury; 2004). There trigger the onset of a painful episode. Sickle has been a great interest in defining factors cell pain may involve any part of the body, that modulate the clinical severity of this and the severity, location, and duration of disease. The only such parameter on which the pain vary latitudinally among patients there is reasonable consensus of opinion is and longitudinally in the same patients the very high concentration and the (Ballas, et al., 1988). pancellular distribution of fetal hemoglobin

(Hb F). The high level of Hb F may decrease The concept that the painful crisis evolves the severity of certain sickle cell syndromes along phases was first introduced by Ballas (Serjeant et al., 2001; Ballas et al., 1988; and Smith (1992) and Akinola et al. (1992) Benjamin et al., 1999; Benjamin, 2001; who independently and almost Benjamin and Payne, 2007; Ballas and simultaneously described the presence of Lussardi, 2005) because of its ability to two phases of the uncomplicated painful inhibit polymerization of the Hb S during the crisis in prospective longitudinal studies of sickling process (Boros et al., 1976; Powars et adults with SCD. The initial phase was al., 1978). In vitro polymer studies of Hb S associated with increasing pain, decreased and F demonstrated that FS hybrids are RBC deformability, increase in the number of excluded from nuclei formation thereby dense cells, red cell distribution width interfering with polymerization in vitro and (RDW), hemoglobin distribution width possibly with the sickling process in vivo (HDW), reticulocyte count, leukocytosis and (Powas, 1990; Francis and Johnson, 1991). In decrease in the number of platelets. The order to have its salutary effect on the

Innovation Solution in Engineering (ISIE) 43 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 second phase was characterized by deformability. On the other hand, negative established pain of maximum severity and correlation was indicated between gradual reversal of the abnormalities of the percentage of dense cells (and of ISC) and the first phase. Later, Ballas (1995) revised the severity of the painful crisis. Thus, patients description of the painful crisis and refined with a high percentage of dense cells had low its evolution into four phases. The phases Hb levels, low RBC deformability, and were called prodromal, initial, established, relatively mild disease. and resolving phases. Beyer et al. (1999) found that the painful crisis also evolves Taken together, the data indicate that along phases in children but the phases were patients with sickle cell anemia and Hb < broken down into 7 and were labelled 15% have a heterogeneous clinical picture. differently. Patients who generate a relatively large number of dense cells and ISC, have Sickle cell pain includes 3 types: acute decreased RBC deformability and have recurrent painful crises, chronic pain milder disease than those whose RBC are syndromes, and neuropathic pain. The acute more deformable. RBC deformability, the painful crisis is the hallmark of the disease percentage of dense cells and the percentage and the most common cause of of ISC seem to have a predictive value of the hospitalization and treatment in the frequency and severity of the sickle cell emergency department. It evolves through 4 painful crisis. phases: prodromal, initial, established, and resolving. Each acute painful episode is Clearly, the above indicated markers can be associated with inflammation that worsens used to clinically predict the onset of pain with recurrent episodes, often culminating in threshold in the pathophysiology of the serious complications and organ damage, disease. In this study, an attempt will be such as acute chest syndrome, multiorgan made to provide a mathematical alternative failure, and sudden death. Three to the prediction of the painful crisis using pathophysiologic events operate in unison the kinetics of the polymerization reaction during the prodromal phase of the crisis: leading to vaso-occlusion. vaso-occlusion, inflammation, and nociception. Aborting the acute painful 2.0 KINETICS OF HEMOGLOBIN SS episode at the prodromal phase could SICKLING potentially prevent or minimize tissue In a recent review, Cohen et al. (2012) damage (Ballas et al., 2012). addressed the challenge facing the elucidation of the kinetics of protein Ballas et al. (2012) have identified other aggregation which is the central theme in the rheological properties of red blood cell understanding of the polymerization reaction characteristics that correlate with the of Hb SS sickling. This challenge was frequency and severity of sickle cell painful attributed to the ability of relating bulk crises. These are red cell deformity and dense experimental measurements of amyloid cell concentration. They showed that red formation to the microscopic assembly blood deformability positively correlated processes that underlie protein aggregation is with the frequency and severity of the critical in order to achieve a quantitative painful crisis. Thus patients with a high RBC understanding of this complex phenomenon. deformability index experience more crises The complexity in the study of protein and crisis days than those with low RBC aggregation arose because the commonly

44 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 available bulk of experimental measurements (Ferrone et al., 1980; Ferrone et al., 1985a, b) cannot be easily related to the microscopic to as high as 35 to 50 at 0.25 g/cc (Hofrichter steps in the mechanism of aggregation. Thus, et al., 1974a,b; Hofrichter et al., 1976a,b; the rate of reaction may become so complex Sunshine et al., 1979). due to the large number of molecular species with "different polymerisation numbers that There have been two principal motivations can inter-convert through a multitude of for the study of haemoglobin S processes". polymerization in mixtures with other hemoglobins. First, haemoglobin S Further complications arise because of the frequently occurs in red cells in combination classes of processes that can contribute to with a large fraction of other hemoglobins protein aggregation phenomena. In broad and increased proportions of normal terms, these processes can be divided into haemoglobin (Hb A), fetal haemoglobin (Hb three categories: (i) nucleation and F) and haemoglobin C (Hb C) result in fragmentation processes that increase the decreased clinical severity (Serjeant, 1985; number of aggregates, (ii) growth processes Bunn and Forget, 1986). Second, that lead to the increase in the sizes of polymerization studies on mixtures have existing aggregates and (iii) dissociation or made a major contribution to the elucidation degradation processes that lead to the of the polymer structure. decrease in size and/or the disappearance of aggregates. Sickle haemoglobin polymerization appears to be precise with respect to location and In spite of the challenges above, attempts directionality of growth. Usually, thermal have been made on the development of fluctuations provide the energy required for kinetic rate laws for protein aggregation. The molecules of sickle hemoglobin that are mechanism of protein aggregation are based competent to form long fibers, to assemble on the following concepts. into small aggregates. This leads to the spontaneous formation of transient species of 2.1 The delay time and SCD severity various sizes. At some critical size (called the Mozzarehhi et al. (1987) has shown that upon nucleus), each additional molecule lowers deoxygenation in the tissue, there is a delay the energy of the aggregate. The formation of period prior to the onset of gelation. This nuclei is thus characterized by molecular delay time is believed to be long enough for fluctuations, and the time to form a nucleus most cells to reach the lungs and be is inherently stochastic. reoxygenated before there is significant polymer formation. During this delay period, 2.2 The double nucleation mechanism the Hb S is unaggregated and behaves very A significant relationship between domains much like normal Hb A. Thus, a knowledge and the kinetics of gelation was first of the equilibrium properties of sickle red established in measurements of the cells is inadequate (and can be misleading) stochastics of gelation in small sample for understanding the pathophysiology of volumes (Ferrone et al., 1980; Ferrone et al,. SCD (Eaton and Hofrichter, 1990a,b, 1994; 1985a,b; Hofrichter, 1986). In those Makhijani et al, 1990). This delay time has experiments, a single domain of polymers been found to depend reciprocally on the was found to form with a rate exhibiting haemoglobin S concentration to the power stochastic fluctuations. Once initiated which varies from about 15 at 0.35 g/cc however, the subsequent growth of the

Innovation Solution in Engineering (ISIE) 45 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 domain showed fully reproducible of kinetic measurements, the heterogeneous deterministic behaviour. This was a pivotal nucleation process was subsequently observation in formulating a double observed directly in differential interference nucleation mechanism, suggesting as it did contrast microscopy (Samuel et al., 1990). that a single molecular event could proliferate into an array of many polymers. The formation of the critical nucleus is The double nucleation mechanism explained thought to be the rate-limiting step in this behaviour by the postulate that new polymer growth. Thus, the kinetics of polymers could nucleate on the surface of polymerization are characterized by pre-existing polymers. That mechanism exponential growth that begins with a period successfully provided a kinetic framework in which so little polymer is present that which described the polymerization reaction there appears to be a delay (the delay time) over six decades of rates in the concentration between induction and the appearance of range, 20-40 g/dl, and the temperature range polymer. The length of the delay time 5-500oC (Ferrone et al. 1985a,b). depends on the solubility of the HbS molecules, which can be varied by changing The nucleation of sickle hemoglobin is a the temperature or ligand saturation. remarkable process involving, in the same reaction, a very strong concentration 2.3 Kinetic Models from literature dependence (up to 50th power) and an We present a summary of four significant exponential time dependence. Reconciliation SCD kinetic models from the literature in of these two disparate characteristics was Table 2. Three of these models are based on made possible by the postulation of a novel, the intimate relationship between double nucleation mechanism in which it polymerization and SCD. A basic assumption was proposed that the surface of a polymer of SCD research has been that inhibition of could catalyze the nucleation of additional polymerization partially will decrease polymers (Ferrone et al., 1980; Ferrone et al., clinical severity. Understanding the 1985a,b). The first polymer forms by polymerization process in detail is therefore homogeneous nucleation, followed by not only important for understanding the elongation. pathophysiology of SCD but is critical to the major problem of developing specific Furthermore, it is postulated that subsequent therapies that could be used in the alleviation polymers may either form by additional of the consequences of the disease. It is clear homogeneous nucleation events or by from the rate equations presented in Table 2 nucleation onto the surface of polymers that for the three models that the parameters have already formed. Once formed by either characterizing the rate models are not easily pathway, the polymers are the same. Nuclei determinable, hence the need for a are assumed to have no special structure but polymerization model that provides simpler maintain the same geometry as monomers and more easily determined parameters. within the polymer. In other words, the Although the kinetic model of Cohen et al. formation of polymers thus could proceed (2012) is simpler, however, ambiguity in either by nucleation in bulk solution defining parameters characterizing SCD (homogeneous nucleation) or by polymer provides another motivation for an nucleation on other polymers (heterogeneous alternative model. nucleation). Originally deduced on the basis

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Table 2: Summary of significant SCD kinetic models from literature Reference Mechanism Rate Equation Reaction Remarks Variables Ferrone et Homogeneous The rate constant: 'γ0: the These al. (1985a) nucleation in monomer variables are sickle activity not easily and where ζ is obtained from the distribution of hemoglobin coefficient at accurately tenth times (Szabo, 1988): the initial determined. monomer concentration; With i*: the nucleus No = Avogadro’s number, and size; V = photolysed volume ci: the With a known value of ζ, the rate constant, concentration of f0 (in mM/sec) can be obtained. aggregates Notation: (nuclei) of size t = tenth time i*; T(t) = distribution of tenth times, t γi*: the activity B = Exponential growth rate of polymerized coefficient for monomers the nucleus; n = point at which domain formation is and observed = Bt0 γ(i*+1): the ζ = homogeneous nucleation rate activity t0 = tenth time measured in a volume with a coefficient for large number of nucleation and no the activated stochastic variation complex г = a gamma function The initial part of the distribution is kept small by the (1 – e-Bt) term but once t > B-1, the distribution becomes a decaying exponential whose decay constant is ζ.

Ferrone et Heterogeneous The rate is given by: The same as The same al. (2002); nucleation and where the primes indicate above except limitations Ferrone crowding in the parameters apply for both (2004) sickle the concentration and activity coefficients of are for attached the hemoglobin attached aggregates of size j*. aggregates in a homogeneous heterogeneous and complex heterogeneous nucleation Auer and Protein ka is the maximal rate of aggregation, the ϴ = aggregation ϴ varies Kashchiev aggregation slope of the α(t) curve at the point of time constant widely (from (2012) inflection, t0 is therefore determined as: n = geometrical seconds to characterization days) because of the steepness it is very which becomes: of the linear sensitive to the portion of the crystallite α(t) data profile nucleation and And the lag time is given by: growth rates and n may vary between 1 to 4

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Cohen et Protein The mechanism of aggregation is suggested n, the reaction There is some al. (2012) aggregation to proceed through primary and secondary order ambiguity pathways. γ, the scaling with regard to Generally, aggregates are created by the exponent some of the dominant mechanism at a rate given by: parameters.

where n= reaction order for the nucleation process. The half time is that time at which the monomeric protein has been sequestered into aggregates to the total initial monomer concentration as a power law:

where the scaling exponent,  can be used to determine the system dominated by primary nucleation or by a secondary pathway.

3.0 A NEW KINETIC MODEL OF reaction as the primary basis for our kinetic VASOOCCLUSION model, using previously developed concepts All kinetic findings so far, have been (Boudart, 1968; Susu and Kunugi, 1980; Susu, explained by homogeneous and/or 1997). In addition, the polymerization leads heterogeneous nucleation mechanism which to progressive increase in whole blood depends on the hemoglobin S concentration viscosity and an increase in the number of to a power which is the number of molecules sickled red cells that initiates activities that contained in the nuclei (Ferrone et al., cause the sickled red cells to become 1985a,b; Ferrone et al., 2002; Ferrone, 2004a,b; structures solid enough to block the blood Auer and Kashchiev, 2012; Cohen et al., vessels (Adams et al., 1992). Thus, it is 2012). Furthermore, the parameters necessary to include the hydrodynamics of contained in these models are not readily blood flow in the overall model for the onset determinable. Because they are mechanism prediction of the pain threshold for SCD. based, the parameters contained aggregate These two models are presented below. information and nucleus details that are not readily determined. It is therefore necessary 3.1 Global kinetics of the autocatalytic to formulate a model that is simple with model of Hb S polymerization fewer parameters that are readily Using previous presentations of autocatalysis determined. Such a model is described here (Boudart, 1968: Susu and Kunugi, 1980; Susu, and it is based on the sigmoidal profile of the 1997) modified to describe the HbS polymerization reaction. polymerization, we have: (3.1) The sigmoid progress profile of the (3.2) polymerization reaction has not been exploited in any kinetic scheme. The delay where A = deoxyhemoglobin S (HbS) time and subsequent exponential growth of C = monomer the polymerization process before P = HbS polymer degeneracy explain the explosive, autocatalytic nature of the reaction. We have, This two-step global kinetic scheme broadly therefore, used the autocatalysis of the defines the kinetics of the HbS

48 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 polymerization reaction. The first step (3.6) defines the primary reaction where deoxyhemoglobin S (HbS) is dissociated to The overall reaction rate, r0 becomes: monomers in a homogeneous scheme (3.7) leading to the formation of a mixture of monomers and aggregates. The second step (3.8) is the explosive, autocatalytic reaction where more monomers are produced from HbS and In terms of fraction converted, Eqn. (3.8) addition of monomers to aggregates in a becomes, homogeneous, heterogeneous reaction scheme to form polymers. This treatment allows the derivation of a global kinetic (3.9) scheme with focus on the kinetic parameters, free of detailed mechanistic considerations. Rearranging gives, The major advantage of this scheme is that (3.10) the resulting rate laws are only functions of kinetic parameters devoid of unquantifiable thermodynamic (e.g. activity coefficients) Rearranging and setting k = k2CA0 and ρ = and sizes of reactive intermediates (e.g. k1/k gives: (3.11) nucleus, monomer and aggregates) that are present in situations where the kinetic (3.12) treatment includes the details of the inter- conversions of these intermediate species. The second derivative of Eqn. (3.12) gives the

point of inflection for the sigmoid curve. The first step in the sequence is assumed to Hence, be first order in Hb S while the accelerating (3.13) second reaction is assumed to be second order. For maximum rate, Eqn. (3.13) is set to zero. The rate of reaction (3.1) is written as: Hence,

(3.3)

Giving, If CAO = initial concentration of A and f = (3.14) fraction of A converted, then Eqn. (3.3) can be written as: (3.4) If , then The maximum rate occurs at f = ½ (3.15) Rearranging yields: If Eqn. (3.12) is integrated with f = 0 at t = 0, (3.5) we have (see Appendix): (3.16) For autocatalysis to occur, the product formed is a catalyst for the reaction. Therefore, the second reaction takes place Let = M, then Eqn. (3.16) is re- with a much higher reaction rate, r2. Then, written as:

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(3.17) independently get t1/2 from other sources. One way of accomplishing this is to utilize (3.18) the equation derivable from the

hydrodynamics of blood flow to get t1/2. Re-arranging yields, (3.19) 3.2 Hydrodynamic models of blood flow

Taking ln of both sides and precipitating out 3.2.1 Prediction of cell position t gives, For red blood cells in the microcirculation, (3.20) they either assume the edge-on position, where they are seen to glide over each other (with the discs aligned horizontally with the At the point of maximum rate, where f = 0.5, centre of the vessel) as they pass through the Eqn. (3.20) reduces to: vessels or the stacked position where the red (3.21) cell are seen as discs packed perpendicular to the centre of the vessel. The cell diameter:

vessel diameter (from clinical analysis and In terms of rate constants, Eqn. (3.21) is: Doppler evaluation respectively) is used to (3.22) determine the position the red cells are likely to assume during its transit in a vessel Eqns. (3.21) and (3.22) gives the time it will (Charm and Kurland, 1974): take to reach the maximum polymerization rate in sickle cells. For the calculation of the The cell diameter: vessel diameter (from onset time for pain threshold, we need the clinical analysis and Doppler evaluation two rate constants (k1 and k2). respectively) is then obtained as (Charm and Kurland, 1974): From Eqn. (3.12), the slope at the point of (3.25) inflection (at f = 0.5) is: Where DC = cell diameter Dv = vessel diameter (3.23) For ratios less than 0.9, the cells assume the Therefore, edge-on position but from 0.9 and above, the cells assume the stacked position where (3.24) occlusion of vessels have a high propensity of occurrence. Therefore, vessels with ≥ 0.9 Equation (3.24) contains three unknowns: the will be considered target vessel for vaso- slope of the conversion profile at 50% occlusion. conversion, the primary (k1) and secondary (k2) rate constants. However, if we know t1/2, 3.2.2 Model for settling velocity of the equation (3.22) can be used to get k1 and k2. RBC Once these rate constants are known, The total amount of force exerted on a equation (3.24) can be used to estimate the particle can be summarized as: value of the slope at 50% conversion. We, of course, can simplify the challenges of reducing the unknowns, if we can

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Force due to Acceleration = Gravity Force – 3.3 Prediction of time of occlusion in vessel Buoyancy Force – Drag Force (3.26) An occlusion would occur at the time the velocity of the red cells (settling velocity, us) For a particle, there are two stages when it becomes less or equal to that of the plasma flows: The acceleration portion and then the velocity, up, that is, us ≤ up (from Eqns. 3.32). portion of constant velocity, also known as The major assumption here is that the terminal velocity or free settling velocity, accelerated polymerization will occur at 50% uS. conversion and the time to reach this 50% conversion is denoted t½ which is the time However, bouyancy force, Fb, is obtained as: the cells approach their terminal velocities and then begin to clog gradually.

(3.27) For a fluid flowing through a pipe, the Poiseuille equation (Charm and Kurland, Hence, for many spheres, 1974) is used to describe the plasma velocity, (3.28) uP, such that: (3.33) While the Drag force, Fd, on a particle is: (3.29) The primary aim of this study is to generate relevant equation for time of crisis using Eqn. Similarly, for many spheres interacting, 3.33. Therefore, we separate the variables in (3.30) Eqn. 3.33 and integrate between limits to obtain:

(3.34) Where Fb = Buoyancy force ρP = density of particle = MCHC value from clinical analysis Therefore, ρ = density of fluid (serum) (3.35) g = gravitational constant

= volume of particle = Actual red cell The time for the onset of pain threshold in volume = (3.31) sickle cell patients is given by Eqn. (3.35). This equation depends on simple where ri = red cell radius from RDW parameters: µ0, viscosity of the plasma (blood); L, the length of the vessel under investigation; us, settling velocity of the red N = number of red blood cells = RBC blood cells; R, the radius of the vessel under (Total red blood cells) investigation; ΔP, the pressure drop across Fd = drag force the vessel. Sa = drag co-efficient AP = area of particle Both the hydrodynamic and kinetic models uS = settling velocity proposed in this work, give time to attain occlusion in the blood vessels. For example, Combining Eqns. (3.29) and (3.31) yields: as sickle hemoglobin polymerization (3.32) progresses, the blood viscosity increases and blood flow (velocity) slows down. The time taken to reach half conversion from the

Innovation Solution in Engineering (ISIE) 51 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 kinetic model in Eqn. (3.21) is therefore taken limits in a machine monitoring device. This as the time to attain the settling velocity of limit is approximately 3 for all participating the red cells from the hydrodynamic model SCD participants. To get the upper limit for in Eqn. (3.35). This assumption is realistic the k ratios, experimentation must be carried because hemoglobin polymerization is out on patients from periods before and up presumed fastest as the red cells gradually to SCD crisis and beyond. Fortunately, there come to a halt. are SCD patients in the participating group that would easily qualify for this The developed mathematical models were experimentation, In Table 3, these candidates then tested with in vivo data collected from can be easily selected from those with one 22 sickle cell patients and 10 controls crisis frequency per month (201F, 205M, 206F (Alagbe, 2017; Alagbe et al., 2016a; Alagbe et ad 208F). The data collected from this long- al., 2017b) and also from in vitro literature term experimentation will be useful in data of Hofrichter (Hofrichter et al., 1974) validating the SCD models. Unfortunately, using MATLAB programming. the in vitro literature data cannot be used for this purpose although it confirms the 4.0 RESULTS AND DISCUSSION prediction that higher rate constant ratios The results of the modeling studies are characterize the actual painful crisis. In the presented in Table 3. The critical parameters only literature data available, the rate of the SCD condition are: the half-life (t1/2), constant ration was approximately calculated which is the time it will take to reach to be 4.29, higher than the value of 3 for the maximum polymerization, the delay time in vivo data. A more important index of (tD), the slope of the sigmoidal profile at 50% monitoring SCD pain crisis is the constancy conversion (S), the rate constant ratio (k1/k2) of the rate constant ratios which provides a and the mean corpuscular haemoglobin useful tool for the design of machine concentration (CAo). The time to reach monitoring of SCD painful crisis. maximum polymerization (t1/2) is the predicted onset of pain threshold in SCD. The calculated onset and delay times are in The delay time (tD) is critical in the minutes for the in vitro data while they were pathophysiology of the sickle cell disease. in days for the in vivo data. The times The slope of the sigmoidal reaction profile is calculated for in vitro data are real as the a measure of the severity of the painful times characterize real polymerization episode; the steeper the slope (the higher its process whereas the times for the in vivo value) the more severe the pain crisis. data are fictitious as the patients were not in crisis. Again, the values of the slopes for in In Table 3, since none of the in vivo vivo data were much higher for the same participants are in crisis during the period of reason. This clearly shows that in vivo data the study, the values of these critical gathered up till the onset of the pain crisis parameters reported are the steady state can truly yield actual delay and onset times. values that are usable as the lower defined

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Table 3: Critical SCD parameters determined from new kinetic model using in vivo and in vitro literature data for validation

Code of Crisis Critical SCD Parameters SCD frequency In vivo data In vitro data+ Participant t1/2, tD, Siv k2/k1 CAo, Temp., t1/2, tD, Sir k2/k1 CAo, days days g/dL OC min. min. g/dL 101F 4 per year 54.96 74.76 0.26 2.75 36.9 15.9 925 308 0.006 4.29 23.3 109F 4 per year 46.39 70.09 0.30 2.85 35.1 16.3 835 308 0.006 4.29 23.3 201F 1per month 36.67 67.17 0.38 2.76 34.1 17 675 182 0.007 4.29 23.3 205M 1 per month 54.87 74.79 0.26 2.93 34.8 17.8 513 143 0.006 4.29 23.3 206F 1 per month 46.76 70.33 0.30 2.87 33.7 18.7 325 118 0.004 4.29 23.3 207M 5 per year 29.73 53.33 0.47 2.97 37.5 19.6 100 100 0.009 4.29 23.3 208F 1 per month 37.08 62.59 0.38 2.69 36.0 20.3 85 40 0.048 4.29 23.3 209F 1 per year 29.20 52.47 0.48 2.78 33.7 210F 1 per year 19.89 30.21 0.70 2.97 33.2 F:Female M:Male + Calorimetric measurement data of the fractional extent of gelation (Hofrichter et al., 1974a) CAO: mean corpuscular hemoglobin concentration

5.0 CONCLUSSION For the first time, a pathway for the development of a threshold pain alert system REFERENCES is elaborated. To facilitate this pathway, we Adams, R.J., Mckie, V., Nicholas, F. (1992) The developed a global kinetic model based on use of transcranial ultrasonography to the autocatalytic nature of the Hb S predict stroke in sickle cell disease. N. polymerization reaction unencumbered by Engl. Med. 326: 605-610. detailed reaction mechanism of the Akinola, N.O., Stevens, S.M.E., Franklin, I.M. polymerization reaction. The kinetic rate (1992) Rheological changes in the expression is characterized by simple rate prodromal and established phases of constants that are easily determined. In sickle cell vaso-occlusive crisis. Br. J. Haematol. 81:598-602. addition, we developed a model that Alagbe, E,E., Susu, A.A., Dosunmu, A.O. (2016) captures the orderly rheological Modeling and Simulation of the characteristics of the vasoocclusion process. Autocatalytic Kinetics of Haemoglobin Together, these two models provide a SS Polymerization: Onset of mathematical description of the sickle cell Polymerization. J. Bioscience Medicine disease that is adaptable for SCD pain 4, 21-27. threshold alert system. The important Auer, S., Kashchiev, D. (2012) Insight into the parameters are identified as the rate constant correlation between lag time and ratio (k2/k1), the delay and onset times and aggregation rate in the kinetics of the slope of the sigmoidal profile of the protein aggregation. https//:arxiv.org/ polymerization reaction. Our in vivo data abs/1006.1869. easily provide low limits for this ratio and Ballas, S.K., Larner, J., Smith, E.D., Surrey, S., paths to all other critical parameters. Thus, a Schwartz, E. and Rappaport, E.F. (1988) machine adaptable diagnostic/monitory Rheological predictors of the severity of device for sickle cell patients is now feasible. the painful sickle cell crisis. Blood 72: 1216-1223.

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Ballas, S.K., Smith, E.D. (1992) Red blood cell cell anemia. J Neurol Neurosurg Psych. changes during the evolution of the 39:1236-1239. sickle cell painful crisis. Blood. 79:2154- Charm, S.E., Kurland, G.S. (1974). Blood flow 2163. and microcirculation. John Wiley & Ballas, S.K.(1995)The sickle cell painful crisis in Sons. adults: phases and. objective signs. Chiang, E.Y. and Frenett, P.S. (2005) Sickle cell Hemoglobin. 19:323-333. vaso-occlusion. Hematol. Oncol. Clin. Ballas, S.K. and Mohandas, N. (2004) Sickle red North Amer. 19, 771-184. cell microrheology and sickle blood Cohen, S.I.A., Vendruscolo, M., Dobson, C.M., rheology. Microcirculation 11(2), 209- Knowles P.J. (2012). From macroscopic 225. measurements to microscopic Ballas, S.K., Lusardi, M. (2005) Hospital mechanisms of protein aggregation. J. readmission for adult acute sickle cell of Mol. Biol., 421, 160-171. painful episodes: frequency, etiology, Cousins, M.J., Bonica, J.J. (1989) Acute pain and and prognostic significance. Am J the injury response: immediate and Hematol.79:17-25. prolonged effects. Reg. Anesth. 14:162- Ballas, S.K. (2007). Current issues in Sickle Cell 179. Pain and Its Management. Hematology Eaton, W.A., Hofrichter, J. (1990a). Sickle cell : 97-105. hemoglobin polymerization. Adv. Ballas, S.K., Gupta, K., Adams-Graves, P. (2012) Protein Chem, 40, 63-279. Sickle cell pain: a critical reappraisal. Eaton, W.A., Hofrichter, J. (1990b) Sickle cell Blood. 120(18): 3647-3656. hemoglobin polymerization. In: Sickle Benjamin, L.J., Dampier, C.D., Jacox, A. (1999) Cell Disease. S.H. Embury, R.P. Hebbel, Guideline for the Management of Acute N. Mohandas and M.H. Steinberg, eds., and Chronic New York, 53-87. Pain in Sickle Cell Disease. American Pain Embury, S.H., Hebbel, R.P., Mohandas, N., Society Clinical Practice Guidelines Steinberg, M.H. eds. (1994) Sickle Cell Series No. 1. Glenview, IL. Disease. Basic Principles and Clinical Benjamin, LJ. (2001) Nature and treatment of Picture. New York: Raven Press. the acute painful episode in sickle cell Embury, S. (2004). Non-So-Simple Process of disease. In: Steinberg MH et al, eds. Sickle Cell Vasoocclusion. Disorders of Hemoglobin: Genetics, Microcirculation 11: 101-113. Pathophysiology, and Clinical Fabry, M.E., Benjamin, L., Lawrence, C., Nagel, Management. Cambridge, pp 671-710. R.L. (1984). An objective sign in painful Benjamin, L.J., Payne, R. (2007) Pain in sickle crisis in sickle cell anemia: The cell disease: a multidimensional concomitant reduction of high density construct. In: Pace B, ed. Renaissance of red cells. Blood 64: 559. Sickle Cell Disease Research in the Ferrone, F.A., Hofrichter, J., Sunshine, H., Genomic Era. London: Imperical Eaton, W.A. (1980). Kinetic studies on College Press, pp 99-118. photolysis-induced gelation of sickle Beyer, J., Simmons, L., Woods, G.M., Woods, cell hemoglobin suggesy a new P.M. (1999) A chronology of mechanism. Biophys J., 32, 361-377. pain/comfort in children with sickle cell Ferrone, F.A., Hofrichter, J., Eaton, W.A. disease. Arch Ped Adolescent Med 153, (1985a). Kinetics of sickle hemoglobin 913-920. polymerization I: Studies using Boros, L., Thomas, C., Weiner, W.J. (1976) temperature-jump and laser photolysis Large cerebral vessel disease in sickle techniques. J. Mol. Biol., 183, 591-610.

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Ferrone, F.A., Hofrichter, J., Eaton, W.A. hemoblobin solutions. Proc Natl Acad (1985b). Kinetics of sickle hemoglobin Sci., 73, 3034-3039. polymerization II: A double nucleation Hofrichter, J. (1986). Kinetics of Sickle mechanism. J. Mol. Biol., 183, 611-631. hemoglobin polymerizatiom nucleation Ferrone, F.A., Ivanova, M. and Jasuja, R. (2002) rates determined from stochastic Heterogeneous nucleation and fluctuations in polymerization progress crowding in sickle hemoglobin: An curves. J. Mol. Biol., 189, 553-571. analytical approach. 82(1), 399-406. Kaul, D.K., Hebbel, R.P. (2000) Ferrone, F.A., Rotter, M.A. (2004a). Crowding Hypoxia/reoxygenation causes and Polymerization of sickle inflammatory response in transgenic hempglobin. J. Mol. Recognit., 17, 497- sickle mice but not in normal mice. J. 504. Clin. Invest. 106:411-420. Ferrone, F.A. (2004b). Polymerization and Makhijani, V.B., Cokelet, G.R., Clark, A. (1990). sickle cell disease: A Molecular View. Dynamics of unloading from sickle Microcirculation, 11(2), 115-128. erythrocytes. Biophys. J., 58, 1025-1052. Fields, H.L. (1987) Pain. New York: McGraw- Mozzarelli, A., Hofrichter, J., Eaton, W.A. Hill. (1987). Delay time of hemoglobin S Francis, R.B. and Johnson, C.S. (1991) Vascular gelation prevents most cells from occlusion in sickle cell disease: current sicklig in vivo. Science, 237, 500-506. concepts and unanswered questions. Powars, D., Wilson, B., Imbus, C. (1978) The Blood 779(7), 1405-1414. natural history of stroke in sickle cell Hofrichter, J., Ross, P.D., Eaton, W.A. (1974a). disease. Am. J. Med. 65:461- 471. Kinetics and mechanism of Platt, O.S. (2000) Sickle cell anemia as an deoxyhemoglobin S gelation: A new inflammatory disease. J. Clin. Invest. approach to understanding sickle cell 106:337-338. disease. Proc. Natl. Acad. Sci. USA, Samuel, R.E., Salmon, E.D., Briehl, R.W. (1990). 71(12), 4864-4868. Nucleation and growth of fibres and Hofrichter, J., Ross, P.D., Eaton, W.A. (1974b). gel formation in sickle cell hemoglobin. Kinetic and Thermodynamic Nature, 354, 833-835. Investigation of Deoxyhemoglobin S Serjeant, G.R. (2001) Sickle Cell Disease, 3rd gelation. In: Hercules JI, Schechetr AN, ed., New York: Oxford University Eaton WA, Jackson RE. In eds. (Ed.), Press. Proceedings of the first National Sunshine. H.R., Hofrichter, J., Eaton, W.A. Symposium on Sickle Cell Disease (pp. (1979). Gelation of sickle cell 43-45). Bethesda, Maryland: DHEW. hemoglobin in mixtures with normal Hofrichter, J., Ross, P.D., Eaton, W.A. (1976a). adult and fetal hemoglobin, J. Mol. Biol, A physical description of hemoglobin S 133, 435-467. gelation. In: Hercules, J.I., Cottam, G.L., Susu, A.A., Kunugi, T. (1980). A novel prolytic Waterman, M.R., Schechter, A.N. decomposition of n-Erosane with Proceedings of the symposium on synthesis gas and K2CO3 catalyzed shift molecular and cellular aspects of sickle reaction. I & EC Proc. Des. Dev., 19, cell disease, Bethesda, Maryland:, 693-699. DHEW publication no. (NIH) 76 – 1007 Susu, A.A. (1997). Chemical Kinetics and : 185 – 223. Heterogeneous Catalysis. CJC Hofrichter, J., Ross, P.D., Eaton, W.A. (1976b). Publishers Nig. Ltd. Supersaturation in sickle cell

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APPENDIX

Integration of Eqn. (3.12) to yield Eqn. (3.16) (3.12h) (3.12)

At f=0 and t = 0, Rearrange to obtain: (3.12i) (3.12a)

Eqn. (3.12i) into eqn. (3.12h) gives By partial fractions, the integral of the LHS of (3.12j) eqn. (3.12a) becomes (3.12b) Multiply through by (1 + ρ)

That is,

(3.12c)

If f = 1, in eqn. (3.12c), then (3.12d) Applying the law of logarithm, (3.12k) Similarly, if f = -ρ , in eqn. (3.12c), then

(3.12e) Take inverse logarithm of eqn. (3.12k) yields

Eqns. (3.12d) and (3.12e) into eqn. (3.12a) gives (3.12f)

Integrating eqn. (3.12f) yields Collect like terms and factorize, (3.12g)

where C = constant of integration (3.16)

Eqn. (3.12g) can be rearranged to

56 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

THE THERMODYNAMIC SYSTEM AS A METAPHOR FOR ENGINEERING EDUCATION IN AFRICA

Adewumi, Michael and Obonyo, Esther The Pennsylvania State University University, Park, PA 16802 USA [email protected]

ABSTRACT This paper uses thermodynamic system as a metaphor for assessing engineering education in Sub-Saharan Africa and offers some recommendations for improvement. The global context is set using thermodynamic environment as analogy. A very important step in solving a problem is defining it. One must determine the intended audience (population or geographical region of interest), similar to a thermodynamic system. The definition of any system also requires one to determine how the conditions outside the system of focus (analogous to the thermodynamic environment) might influence and/or constrain possible solutions. The authors use the thinking that underpins the functioning of a thermodynamic system to identify the critical challenges limiting optimal performance within SSA’s engineering education system. Their perspectives are informed by their observations as practicing engineers and avid scholars of the global higher education landscape. They have both engaged with several engineering education programs around the world over the past two decades. The viewpoints expressed in this article are also informed by observations that they have made through their educational and professional experiences in Africa (particularly West and East Africa), the UK and USA. The discussion in the paper culminates into key recommendations for transforming engineering education in the African context through leveraging the convening power of professional engineering societies such as the Nigerian Academy of Engineering as well as governing agencies at both the regional and national levels.

Key Words: Engineering Education, Soft Skills, Entrepreneurial Mindset, Local Relevance, Globalization

1. INTRODUCTION complexities affecting the demand and he persistent, solution-resistant supply of engineers in this region. There problems in Sub-Sahara Africa (SSA) have been some reported concerns that many T can be directly linked to the shortage African engineering programs produce in supply of engineers both in terms of graduates who lack the critical and systems quality and quantity. Based on the findings thinking skills, knowledge and experience published in the UNESCO Engineering required to design and manage the delivery Report (UNESCO, 2010), an engineer in the of large scale projects and products in a cost- western world serves between 200 and 500 efficient and timely manner. The findings of people, while their counterpart in a the South African “Numbers and Needs” developing countries serves 10,000. Clearly, study (Lawless, 2007) support this position. the number of graduating engineers is less than the demand for engineers in Sub-Sahara The authors contend that the mismatch in African countries. Interestingly, there is a supply and demand of engineers in the Sub- high rate of unemployment among Saharan African context is symptomatic of engineering graduates in SSA (Rutto, 2015). the systemic failures in the engineering This suggests that there is a hidden layer of education enterprise. More than ever before,

Innovation Solution in Engineering (ISIE) 57 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 engineering educators and academic intended audience or population or administrators across the US have geographical region; which in essence is akin recognized the importance of educational to the process of defining the thermodynamic experiences that emphasize equipping system. It is impossible for one to adequately students with skillset to function as problem address the behavior of any system without solvers. For example, in a 2017 presentation determining how the conditions outside the to the University Faculty Senate, Penn State system of focus would influence and/or President Eric Barron pointed out that constrain possible solutions. Such teaching can no longer be limited to externalities are characterized here as the providing content using pedagogies that are thermodynamic environment. The engineer rooted in pedagogies from the previous seeks solution to a problem, rather than just decades or even centuries. To his point, the knowing why the problem, thus setting him/ teaching practices in the Sub-Saharan African her apart from a scientist. It can be argued context have not changed much since the that while the scientist focuses on knowing 1960s, when most countries gained their why as the end in and of itself, the engineer independence. However, the world has gone wants to know why only as a means to an end through a drastic make-over, with the most (see Petroski, 2010). The engineer wants to prosperous nations leaping from a heavy know why, so as to generate information that reliance on manufacturing to promoting can be used to solve a specific problem in the economic growth and development through real world. The engineers ask “why’ to, for cutting-edge innovations anchored in new example, improve a process or develop a knowledge and information technology. In new or better product. The scientist can focus this knowledge economy, progress relies on generalities, but the engineer must deal more on mining data and using result to with specificities (see Ruben, 2017). Success in improve processes and products. a scientific endeavor may include developing a theory; whereas success in an engineering Given that content is now available - mostly endeavor requires one to advance beyond for free in cyberspace - and students know theory – the theory must be translated into how to access it, President Barron asserted tangible products and processes. Engineers that university teaching must shift to adding are therefore creative problem solvers – trained value to the content through self-directed, to solve practical, human problems. It is the student-engagement instructional authors’ contention that engineering training approaches. Furthermore, teaching must in SSA needs to get back to these basics. inspire and empower the learners to use the acquired knowledge to develop new ideas, The authors’ perspectives are informed by products, and processes that improve lives. their observations as practicing engineers President Barron’s position, essentially, boils and avid scholars of global higher education down to this: ‘Make education relevant to the who have had the opportunity to observe need of the students, and the need of their engineering education around the world at a local community; and ultimately the global fairly close range over the past two decades. community.’ The viewpoints expressed in this article are also informed by observations made by the This paper analyzes engineering education in authors through educational and SSA using, thermodynamic system as a professional experiences in SSA (particularly metaphor. A very important step in defining West and East Africa), the UK and USA. The the problem is determining apriori the thinking that underpins the functioning of

58 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 the thermodynamic system is used to also adapting to and mitigating the impacts identify the critical challenges limiting of other pressing issues, such as climate optimal performance within SSA’s change, or increasingly urbanized engineering education system. The global populations. Engineers also contribute to context is analogized to the thermodynamic efforts directed at providing equitable access environment. In the final section of the to health care. They can solve problems paper, the authors propose some emanating from both natural and man-made recommendations for transforming disasters. They can develop innovative engineering education in the African context resource-efficient strategies that enhance through leveraging the convening power of environmental protection. In essence, professional engineering societies such as the engineering education that is relevant for the Nigerian Academy of Engineering. 21st century should equip students to ‘connect social needs with innovation and 2. Engineering Education as a commercial applications.’ Unfortunately, the Development Enterprise current engineering education in SSA is so heavily focused on the technical aspects of 2.1 Contextual Background: Engineering engineering that there are limited education that is relevant to the needs of the opportunities to expose students to subjects 21st century must provide educational that will enable them to make a direct experiences that immerse students in the connection between their training and the fundamental theories and principles of their local social-economic realities. chosen disciplinary area of focus. This need must be addressed without losing sight of The definition of what is relevant for the 21st how the wider world functions as an century requires an appreciation of the interlinked and interdependent system. We implications of globalization. The 2008 must not lose sight of the historical practice financial and economic crisis, global health of engineering. In their article, “What threats such as Ebola and Zika, as well the engineering is, and what engineers do,” Tony impacts of both natural and man-made Marjoram and Yixin Zhong point out that the disasters, have increased the understanding word “engineer” was commonly used in the that the risk factors in the global landscape 1300s to describe a person who operated are interdependent and interconnected. military engines (Marjoram and Yixin, 2010). Developing innovative engineering solutions The word engine was derived from the Latin to address continuously evolving complex word ingenium, which is the root word for problems requires multidisciplinary ingenuity or cleverness and invention. Prior approach, critical and systems thinking, to specialization of trades and the emergence entrepreneurism and a robust understanding of the different engineering disciplines, there of social issues within a global context. was a close connectedness of the “art” and the “technical” in the work of an engineer. The authors have observed with regret that Granted, definitions evolve. This the engineering education enterprise in SSA notwithstanding, it is widely acknowledged is inadvertently underestimating the impact that engineers can play a pivotal role in of globalization on the employability of their efforts directed at addressing the most graduates. This is best exemplified by what pressing societal challenges (UNESCO, 2010). happens in East Africa during the resource Engineers can tackle the coupled issues of mobilization phase for large engineering providing access to food, energy, water while projects such as the Standard Gauge Railway

Innovation Solution in Engineering (ISIE) 59 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

(SGR) and ports construction projects. These this to work, people must acknowledge and projects continue to rely heavily on foreign fully appreciate their interdependence. capital and, by extension, foreign Citizens of what Friedman describes a flat human/technical assistance. This is largely world are deemed to be more willing to because of concerns that the local engineers participate in the open sharing of are inadequately prepared to deal with the information. If done right, a flattened world underlying complexities of infrastructural would make people better global citizens projects that are radically different from the with each person assuming his/her full existing assets (Kenya Engineer, 2017). This responsibility as a steward of both the actually compounds the challenge of a environment and our limited resources. It is mismatch between needs and skills, seeing important to note that this endeavor would that the graduating students have limited require holding everyone accountable to the access to on-the-job training opportunities. principles of fairness, equity and justice. In The needs and skills mismatch issue has his sequel, Hot, Flat, and Crowded, Friedman become a self-reinforcing problem. To solve (2008) discussed how environmental it, engineering educators must prioritize on challenges, such as climate change and giving their students creative tools that can population explosion, have heightened the help them use their unique understanding of competition for resources in a “flat world.” the local context as their competitive Friedman believes that we live in a survival- advantage. Unless the engineering education of-the-fittest world, where entrepreneurial programs in SSA undergo a drastic competition is always in flux and economic transformation, the average African instability is never-ending. If the status quo engineering graduate is going to keep is left unchecked, “the weak will fall farther walking away empty-handed from job behind.” Left unchecked, levelling of the opportunities that would challenge them into playing field could inadvertently leave the developing 21st Century-relevant critical and less powerful nations – the developing systems thinking skills as well as expertise countries - more susceptible to falling prey to required to manage complex engineering the more powerful and better-resourced projects. nations, just like the gazelle falls prey to the lion! 2.2 The Global Context: The viewpoint on the global context and engineering education Working in a synergistic manner will also be in SSA, as expressed here, is informed in part advantageous. In nature, lions sometimes by the work of the best-selling author and cooperate to kill a bigger animal such like popular New York Times columnist, Thomas wildebeest for increased efficiency and Friedman. In The World is Flat, Friedman effectiveness. Once the wildebeest is dead, (2005) contends that borders are a thing of the lions share the spoils in a mutually the past. For Friedman, nations or beneficial manner. The inverse also happens nationalities no longer exist. Instead, he when the wildebeest work together; the lion envisions a world made up of lions and will always retreat. There is strength in gazelles—lions being the world’s numbers. Cooperation without subjugation is superpowers (the predators) and gazelles the key to success. The level of cooperation (the prey) being the developing countries. that happens within African institutions is inadequate. To compete successfully in the Breaking of barriers is beneficial because it 21st Century, engineering schools must be increases humanity’s interconnectivity. For intentional and purposeful about pursuing

60 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 strategic partnerships with other institutions requirement for successful careers in the 21st locally, regionally and globally. Century, the Global Century. The definition of the local environment for, say, an African 2.3 The Global versus Local Environment: country should be informed in part by the As previously stated, understanding the global imperatives as spelled out in the environment is a critical part of problem United Nations’ 2030 Sustainable definition. The term environment, as used Development Goals (SDGs). here, is more than a generic reference point. The environment is the context from which the student operates and is therefore most familiar with – namely his/her village, town, or even country. This “environment” must be used as the backdrop for the training of engineering students. In the introductory section, the authors presented the thermodynamic system as an analogy for the sort of thinking that is required to transform engineering education. When tackling a thermodynamic problem, one must begin with the definition of the system – the relevant region of interest. The space outside the system is the environment. Generally speaking, the environment is much larger Source: The 17 Sustainable Development Goals (see than the system, sometimes infinitely larger. URL 2) What happens within the system and in Figure 1: UN SDGs larger the environment influence the behavior of the former. The system’s Generally speaking, the 17 SDGs can be influence on the environment is limited grouped into 3 overarching global because of the enormous size advantage that imperatives: the latter has over the former. This 1. Managing limited natural resources characterization of the environment is equitably and with a sense of urgency analogous to the satisfaction of the condition given the growing pressure from the of constancy of thermodynamic properties burgeoning population; that are observed in the interactions between 2. Maintaining the integrity of the the environment the system. environment while ensuring that there is equitable economic growth, and; The larger global context can be 3. Harnessing global interdependence conceptualized as playing a similar role in through functioning in the local context engineering education to what the as global citizens. environment does in relation to a thermodynamic system. The global 2.4 The Local Environment: The engineer landscape determines some of the must be cognizant of the knowledge inherent imperatives for engineering education and in the local environment in which the the need to empower African engineering proposed new process and/or product is students to think globally without losing going to be used. Many a time, the value of sight of the local context. This is a knowledge developed outside of the social

Innovation Solution in Engineering (ISIE) 61 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 constructs of the academy is ignored, or insights on the things that they have worse, discounted. Yet there are several personally experienced. Such insights have examples of very successful solutions to local been known to play a critical role in ‘cracking problems that emerged without the use of the code’ of leveraging science to enhance the say, a system of non-linear partial differential performance of a local solution. equations and sophisticated numerical 3. Salient Issues Facing Engineering algorithms or reliance on data from Education in Africa laboratory experiments. While there are myriad issues that affect the training of engineers in SSA, the discussion It is also easy for one to dismiss local in this section will focus on the most salient knowledge as lacking intellectual rigor ones. because many times, it manifests itself in forms that cannot be easily linked to the 3.1 Issue No. 1 - One-Dimensional sound principles of science. Any difficulties Training: The African engineering education experienced in an attempt to make a training is largely one-dimensional. It is correlation to science should not be confused strongly biased towards imparting technical for a lack of a scientific explanation. Consider knowledge – there is a very strong emphasis the act of juggling. A show in which a juggler on engineering-related facts. The curricula for throws multiple balls in the air without a typical engineering course in the African missing a beat is perceived by some as magic context does not include liberal arts-oriented or a trick. Yet an enlightened person knows subjects such as history, arts, music, that the act of juggling balls is grounded in economics, management, international particle dynamics and physics - there is no relations, and psychology. One might magic in juggling. This should be the lens question the value of including such subjects, through which local knowledge is viewed – which at first glance, may not appear to be ‘I do not know why it works’ does not mean directly related to fundamental principles of ‘it is not scientific.’ engineering. The authors respectfully posit that such subjects are vital to both the Engineering students in African institutions development and success of engineers in the must be encouraged to maintain an open 21st century. First of all, such courses enhance mind when interacting with local one’s ability to integrate disparate (traditional) experts to avoid jumping to the knowledge in a coherent manner when wrong conclusion. The students must working with ill-defined and/or unfamiliar discipline their thinking when seeking to problems. Secondly, all the decisions made understand the local environment. They during the engineering design process must also refrain from proposing solutions require a mastery of soft skills such as until they have considered all the pertinent communication, leadership and team issues required to fully appreciate the building. This is especially critical for experiential, cultural and social values graduates aspiring for careers in private embodied by the local people. They should practice. Should a person focus solely on be encouraged to express intellectual using technical knowledge when developing curiosity in a respectful manner. If the local and implementing an engineering solution, experts perceive engineering students as invariably, some soft skill-related problems being humble and non-judgmental learners will emerge. Such problems could manifest rather than know-it-alls, they (the local themselves in the form of demonstrating experts) will be more willing to share inadequate leadership skills when managing

62 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 employees for peak performance, selling balanced by the need to collaboratively ideas and new products as well as cultivating monitor the linkages that compound the a culture of prioritizing on customer strain on limited resources. It is also known satisfaction. Working in teams, even when all that embracing global diversity promotes the members are technocrats, to execute creativity and innovation. African engineers successful engineering projects requires non- must be equipped with the skillsets that will technical skills. It is, therefore, important for allow them to work seamlessly with people the graduating engineers to be proficient in from different parts of the world. They must the soft skills required to capture both the learn new skillsets that empower them to quantitative as well as qualitative design navigate their way around the nuances that objectives while capturing and developing come with global diversity. In order for them insights from user requirements. to advance to global leadership roles in the design and development of new products In thermodynamics terms, the space defining and processes, they must be perceived by the environment should be viewed as a potential employers as well-rounded three-dimensional space whose dimensional individuals who understand the value of axes are technical, environmental and human. A cultural diversity. The engineering students holistic educational experience will enhance must also understand that there are some the graduating student’s ability to think in a fundamental principles that they must abide three-dimensional manner through by if they want to position themselves as embracing the technical, the environmental high potential performers who are also and the human dimensions. When exposed problem solvers in a world that has now to this form of training, the students will become more like a global village. learn how to work with complexities and ambiguities. They will also have an enhanced 3.2 Issue No. 2 – Ignoring Local Context: appreciation of the market forces and how Engineering education in SSA is, in many such forces shape the adoption of their respects, disconnected from the students’ life products and processes. The job of the experiences. Consider the following scenario. engineer is to solve societal problems through creating products and/or processes A Nigerian student, who grew up in the that improve the quality of life humanity in rural area, having been successful in the some respects. The training should therefore relevant university entrance exams, is emphasize the fact that the primary goal of admitted to study Mechanical Engineering, any engineering endeavor transcends at University of Greatness (UG). The rural creating better products or processes. Success environment in which he grew up can be must be defined as delivering of new characterized as a world in which water is products and processes that make life better for fetched from the stream, fields are cultivated people, while maintaining a safe and habitable using hoes and cutlasses and clothes are environment. washed by hand, sometimes using indigenous soap. The context of his life prior Life in the 21st century is complicated. Global to joining UG was agrarian in nature. On the economic order - along with the internet and first day in class, his professor, inspired by connectivity - have “flattened” the earth. The the subject that is making the news in the resulting higher level of interdependence industrialized countries, uses the principles calls for healthy competition – the quest for of designing driverless cars to introduce the economic growth and prosperity must be course. The professor is oblivious to the fact

Innovation Solution in Engineering (ISIE) 63 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 that this poor student has never seen the environment. An African student is once inside of an internal combustion engine! The more left to imagine examples that s/he student is left to imagine the unimaginable. cannot relate to. Learning becomes divorced There is a missed opportunity here to from context – which needlessly puts increase impact with respect to achieving the otherwise bright students at a disadvantage. learning objectives through building on what This problem can be addressed in part the student is already familiar. In this through encouraging African professors to example, the educator should have used the publish more locally-relevant textbooks. At student’s previous knowledge as a building the very least, they can develop a block. Without doing so, this student is compendium to the existing texts that forced to learn everything from the top-down contextualizes the engineering design rather than from the ground-up. When a objectives using examples drawn from their student’s life journey is ignored, s/he is left students’ local environment. unclear on the context for the problem solving goals as well as the societal relevance The authors readily admit that there is a of what is being taught. The idea of a preference for the western culture with driverless car would sound like science respect to the university experience African fiction to a new student from an agrarian students that extends beyond academics. The context! disconnection from reality that is happening The failure to use previous life experiences as in class also happens outside class. The building blocks for learning can also have students are expected to add value to their detrimental effects on the performance of the local community, yet they are increasingly students during assessment. When a being desensitized to things that they can disproportionately large amount of the relate to, given their life experiences. This experiential knowledge gained over the desensitization has an adverse effect on their course of a student’s life is rendered sense of responsibility as patriotic citizens. If irrelevant, learning new things becomes we want the students to think globally and act more challenging. The student is required to locally, educators must be intentional and grapple with basic engineering concepts purposeful about bringing more local issues while also imagining a context that is so to the classroom. foreign to him/ her that one might as well be talking about Mars! This creates what is often 3.3 Issue No. 3 - Job Expectations: In the referred to in mathematical modeling as a western world, students are increasingly jump discontinuity. The classroom seeking to launch out on their own as environment should promote openness. The entrepreneurs. Many of those who seek students should be encouraged to share their employment do not expect to stay in the personal experiences. Educators can leverage same organization for more than 3-5 years. on these experiences to build coherent value- Generally speaking, African students still adding knowledge based on the application attend engineering schools with the context. expectation that, upon graduation, they will be employed by a large organization such as Here is another dilemma - most engineering a multinational corporation, and enjoy good textbooks used in SSA are written by foreign earnings for the rest of their working life. authors and are therefore western-centric. While this view of the practice of engineering The examples used to illustrate engineering may have been true at one time (though concepts are drawn from the author’s local certainly not for everyone), things have

64 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 changed. We no longer live in a punch-in, The lack of adequate resources, particularly punch-out world. Engineering students funding, is a common problem affecting should be encouraged to think innovatively engineering programs both in African and be equipped with skill sets that will countries and in the US. This encourage them to take calculated risks. They notwithstanding, it is the contention of this should explore ways of adding value to their paper that providing additional financial local environment through solving local resources would constitute only a partial problems. They must not limit their thinking solution. What is truly needed is a through focusing on career aspirations that transformation of the engineering education could potentially make them like lifelong job enterprise. In many respects, the engineering seekers given the mismatch in demand and graduates from African institutions are not supply of engineers as discussed in a fully prepared for successful careers in the previous section. 21st Century. Engineering education must be understood by all as the process through In the early 1990s, the first author benefited which students acquire knowledge that they greatly from his interactions with late can use to develop innovative solutions to Engineer Teju Oyeleye. He challenged the societal challenges, starting with the local author to move back to Nigeria, and quickly issues. This position is closely aligned with dismissed his concerns over finding a good the recommendations that arose from the job with this refrain - “at your level, you NSF/ASEE’s (2013) deliberations on should come back home to create jobs and transforming engineering educations. not as a job seeker.” Engr. Oyeleye provided Societal issues must also be viewed through him with data on the potential for mining the lens of an interconnected and and manufacturing opportunities in Nigeria interdependence global landscape. The based on findings published in several problems facing SSA are intricately linked reports. His position was: ‘Why don’t you with the rest of the globe. In addition to study these opportunities carefully, identify broadening their view of the world, we must where you can add value using your teach the students how to think 3D - that is, technical knowledge and then think think of the technical, environmental and creatively about how to translate these human dimensions. opportunity to profit.’ This discussion unveiled the fundamental deficiency in the So how do we go about training an engineer author’s earlier training as an engineer – the who thinks in these three dimensions? The seeds for entrepreneurial thinking were not authors propose a 3-Step change process. sowed. There is no question that engineers need technical knowledge. But, they also 4.1 Step 1 - Integrating Local Knowledge: need a variety of skills, and the correct The first step is that teachers must be much mindset. The modern engineer must think in more than just purveyors of contents. Today, an entrepreneurial manner and also commit the savvy student can source technical to continuous growth through life-long contents from a wide variety of sources – just learning – s/he must continuously update google it! The teachers must focus on the and re-tool his/her skills to remain relevant value-adding aspect of making the content in a rapidly changing, globalized world. relevant to the local environment. As previously stated, there seems to be a 4. Educating Successful Engineers for the decoupling of the Africa students’ life 21st Century experiences from his/her engineering

Innovation Solution in Engineering (ISIE) 65 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 training. Prior to attending a university, each training must go beyond offering student has experiential opportunities to complementary courses. The development of develop some unique gifts, skills, talents, and soft and transferrable skills must also be knowledge through life experiences. These integrated into the engineering courses. must be valued, and not discounted or Engineering students much be taught the dismissed as irrelevant, albeit inadvertently. entrepreneurial mindset that enables them to think “beyond the job.” Consider this Engineering educators must prioritize on scenario - an Engineer discovers a new seamlessly integrating what the students chemical composition that makes good, have already experienced with what they quality cloth-washing detergent for a lower need to know! For example, while teaching cost than conventional detergents. If the game theory or probability principles, why engineer does not already work for a not focus on the game of Ayo1 instead of detergent company, what would s/he do? baseball? Why focus solely on oil reservoirs Perhaps s/he could sell this new discovery to in Texas when there is an opportunity in to UAC. But how would the student know use, for example Nigerian oil fields? In whether that was the right decision to make? addition to teaching the African students And what if the engineer wanted to start up about the latest 3D-printed fabrics, we can his/her own company but gave up without use the works of the ingenious African trying because of not knowing where to get weavers. We can draw valuable lessons support? There is a need to provide training through a systematic study of the techniques to engineers, both conceptually and used by these highly skilled weavers. Such practically, on how to file patents, handle insights could inform the design and marketing and advertising, and even in some development of the next generation of cases how to figure out an entirely new weaving machines perhaps plying 3D delivery system for a product. In essence, we manufacturing! must teach engineering students to think “beyond the job.” 4.2 Step 2 - Three-Dimensional Education: Beyond localizing the curriculum, the The education process must also prepare the educational experiences must also be students for the reality that awaits them transformed into a multi-faceted offering. upon graduation. Given the high Engineers must be trained within an unemployment rates in most SSA countries, interdisciplinary framework. Graduating it is clear that these students are not students must be well-rounded professionals guaranteed to get a steady, long-term job. equipped with skillsets and tools that give Fortunately, many African children have them competitive edge. They must learn innate entrepreneurial skills. The first author these through soft skills training both within hawked goods as a child in the local market – and outside of regular engineering courses. It he was not the only child doing this. Many is a complete paradigm shift – but one that is African children, through life experiences, necessary. Engineering programs should have an innate understanding of the must offer and require the students to take economics of supply and demand. They courses such as economics, business, know that if they are, for example, the only international politics, foreign languages, family in town that sells baskets, can charge marketing, psychology, and the like. This more than if they have a competitor.

1 Ayo is a very popular traditional game played in South-Western Nigeria

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4.3 Step 3 - Creative Application of Engineers must excel in both creative and Engineering Skills to Local and Global holistic thinking. They must combine the Problems: This is the sad reality - a country technical, the entrepreneurial, the local, and such as Nigeria, with its long history of the global. They must always ask themselves producing engineers, still lacks basic this important question when confronting infrastructure. How can it be, that in Africa’s societal problems that remain solutions- number one producer of oil, with possibly resistant: ‘What is the real issue here, and the lowest cost of production per barrel in what can we do to fix it?’ the world, many people are completely without power? The energy poverty problem The African engineering education enterprise is not limited to rural areas. Even in major will not rise up to the challenge of preparing cities such as Lagos, citizens can only truly students to deal aptly with global rely on a supply of electricity for a few hours complexity, diversity, and change without per day. the development of public policy instruments based on more robust models In the rural parts of SSA countries, many for citizen engagement. The absence of these families still use Kerosene lamps as a light instruments and models have limited the source at night. It is known that pollutants impact of reforms in the African higher from Kerosene fuel is harmful to human education system, including the engineering health. Why have they not been substituted enterprise. Few people understand that a with solar lamps? SSA gets plenty of sun. It knowledge gap is at the root of under- would save money that such families spend investment of public funds into the on buying Kerosene, and may very well save engineering enterprise (Matthews et al. 2012). lives. The extent to which engineering solutions can contribute to the realization of positive Obviously, these issues are multi-faceted and outcomes in multiple sectors is often highly systemic. However, at the most basic overlooked. Because of this knowledge gap, level, the authors suggest that there is a governments in SSA often fail to sufficiently missed opportunity to think of the bigger legislate and safeguard engineering picture. Take, for example, clay pots that are standards (Rutto, 2015 and Ramos, 2014). used in many rural homes in Africa to store Insights can be drawn from the significant drinking water, also keep the water cool investments made by the US government to naturally – they serve almost the purpose of define a future-ready engineering education natural refrigerator! These clay pots are both agenda. This is exemplified in National simple and incredibly effective. Why has no Science Board’s report titled Move Forward to one researched the properties of these clay Improve Engineering Education (NBS, 2007). pots to improve their performance or The National Academy of Engineering has explored their use in other applications? also played a pivotal role in the Things needs to change. African engineers transformation of engineering education aspiring for successful careers in the 21st through, for example, defining the following century must be resourceful, creative and 14 Grand Challenges: 1) Make Solar Energy locally-relevant. They must leverage the Economical; 2) Provide Energy from Fusion; resourcefulness of their childhood – of their 3) Develop Carbon Sequestration Methods ; local context – and apply it to larger issues. 4) Manage the Nitrogen Cycle; 5) Provide Access to Clean Water; 6) Engineer Better Medicines; 7) Advance Health Informatics; 8)

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Secure Cyberspace; 9) Prevent Nuclear ability to apply knowledge and skills in real- Terror; 10) Restore and Improve Urban world settings. Infrastructure; 11) Reverse Engineer the Brain; 13) Enhance Virtual Reality; 14) Broadening the classroom experience to Advance Personalized Learning (see URL 4). allow African students to take courses outside engineering disciplines will require 5. Discussion and Conclusion some creative curricular revisions. Some In response to targets set by the National lessons can be drawn from western countries Academy of Engineering and educational such as the US, where the industry objectives defined by the accreditation satisfaction rating of the quality of the organizations providing oversight for graduating engineering students is as high as professionalism in the practice of engineers, 81% (Rutto, 2015). This is partly because all the leading US universities have made engineering education programs in the US significant investments to transform constantly make deliberate attempts to listen engineering education (Blessing 2008). These to the needs of their customer – the investments include providing engineering employers, and make the necessary students with classroom experiences adjustments to their programs. In addition, augmented with co-curriculum activities that they have made significant investments in enhance their abilities with respect to promoting entrepreneurial mindset among understanding the bigger picture, students. The authors would like to see that recognizing opportunities, evaluating more of this sort of industry engagement in markets and learning from their mistakes. the African context. For this transformation Some of these learning needs are being met to occur, the government will also have to through encouraging students to take change some of its policy instruments. elective courses outside of the engineering Policies that allows government agencies to disciplines. dictate curricular requirements to the engineering programs limit the options that Much of what will be exciting and valuable universities have to provide a holistic in the twenty-first century will be the work educational experience for engineering of engineers who can collaboratively engage students. with people from different professional backgrounds to evolve “tiny systems As the body of the foremost engineering technology” and discipline-specific strategies thinkers in the country, the Nigerian into solutions embedded in rapidly changing Academy of Engineering (NAE) is uniquely societal needs (see URL3 and Blessing, 2008). positioned to catalyze the proposed Part of the knowledge transfer will require transformation of engineering education in synergies with the liberal arts programs that Nigeria. This could also serve as an example in the US constitute what is commonly for other SSA countries. More specifically, referred to as liberal education. As the NAE could champion the development of articulated by the American Association of a blueprint that sets priorities and provides Colleges and Universities, liberal education oversight for efforts directed at: helps students to develop a sense of social  Informing Policy – equipping policy responsibility, as well as strong and makers with the knowledge needed to transferable intellectual and practical skills enhance engineering education, while such as communication, analytical and respecting the need for the university to problem-solving skills, and a demonstrated play its autonomous custodial role of

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adherence to discipline-specific entrepreneurial engineering requirements for accreditation; ecosystem for future generations: The  Facilitating curriculum reform – avoiding Kern Entrepreneurship Education generic, cookie-cutter approach Network. Paper presented at 2008 through sowing seeds of innovation in Annual Conference & Exposition, the engineering education enterprise; Pittsburgh, Pennsylvania.  Contextualizing and personalizing learning – Kenyan Engineer (2017)’s review of ensuring that there is seamless Engineering Education in Kenya, integration of insights from both the http://www.kenyaengineer.co.ke/the- local and global context in the state-of-engineering-education-in- educational programs; kenya/  Catalyzing outcome-based educational Lawless, A., 2007, Numbers & Needs: programs – developing outcome-based Addressing Imbalances in the Civil courses, and; Engineering Profession, South  Leveraging global mobility - making use of African Institution of Civil the African diaspora community to Engineering (SAICE). deploy army of globally savvy Matthews P., Ryan-Collins, L, Wells, J., technocrats to help transform the Sillem, H. and Wright, H., 2012, educational experiences for students. Engineers for Africa: identifying engineering capacity needs in sub- The authors contend that if these Saharan Africa, Proceedings of the fundamental changes are made, the African Institution of Civil Engineers - engineering education enterprise will be Municipal Engineer, Volume 165 transformed for the better and its graduating Issue 4, 187-188 engineers will prosper in the increasingly Marjoram, Tony; Zhong Yixin, 2010, What globalized 21st Century. Engineering is, What Engineers do, Engineering: Issues, challenges and Acknowledgements: The starting point for opportunities for development, this paper derives from several speeches UNESCO. delivered over the past year by the first NBS, 2007, Moving Forward to Improve author. He acknowledges the generous Engineering Education, Available contributions of his assistant, Mr. Nathan online at https://www.nsf.gov/ Rufo, who did the research that crystallized pubs/2007/nsb07122/index.jsp, Last into the speeches. accessed January 28, 2018. Petroski, H., 2010 Engineering Is Not Science, References And confusing the two keeps us from ASEE (2013) Transforming Undergraduate solving the problems of the world, Education in Engineering, Phase I: The IEEE Spectrum Newsletter, Synthesizing and Integrating Available online at https://spectrum. Industry Perspectives, May 9-10, 2013 ieee.org/at-work/tech- Workshop Report, Available online at careers/engineering-is-not-science, https://www.asee.org/TUEE_PhaseI_ last accessed January 28, 2018. WorkshopReport.pdf, last accessed Ramos, Y.J.R., 2014, Science and Technology January 2018. for Development in Sub-Saharan Blessing, J., Mekemson, K., & Pistrui, D. Africa: Key Topics, Challenges and (2008, June). Building an Opportunities” London: SciDev.Net.

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Rutto, D.M., 2015, Industry Demands and URL 2: https://sustainabledevelopment. Future of Engineering un.org/sdgs (Last accessed Jan 28, Education in Kenya, International Journal of 2018) Engineering Pedagogy, Vol. 5 Issue 2, URL 3: https://engineeringunleashed.com/ p31-36. (Last accessed Jan 28, 2018) UNESCO, 2010, Engineering: Issues, URL 4: http://www.engineeringchallenges. Challenges and Opportunities for org/ (Last accessed Jan 28, 2018) Development, Available online at Zhang, & Bai, 2009, Comparative Study on http://unesdoc.unesco.org/images/001 Engineering Education in 8/001897/189753e.pdf, last accessed China and USA, Available online at: January 28 2018. https://web.wpi.edu/Pubs/E- URL 1: https://mchumor.com/ (Last accessed project/Available/E-project-082509- Jan 28, 2018) 224412/unrestricted/Final_Report.pdf, last accessed January 28 2018.

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An Innovative Technique For Power Quality Assessment In Electric Utility Networks

Frank N. Okafor, Osita U. Omeje, and Adeola O. Balogun Department of Electrical and Electronics Engineering, University of Lagos, Nigeria. * Corresponding author: [email protected] Tel.: +234-805-963-4488

ABSTRACT The development of modern Electricity markets has bestowed the status of “commodity” on Electric Power which, in consequence, must be subjected to some specifications of quality to worth its price. Power Quality (PQ) is characterized by such distortion elements as harmonics, flicker, voltage and current imbalance etc. Of all these, the most prominent is harmonics. The major challenge facing power system market operators is how to identify harmonic sources and quantify their individual contributions at a Point of Common Coupling (PCC). In a typical Distribution Network, this is necessary so that appropriate penalties can be imposed on the real culprits. Earlier approaches to the solution of the problem relied on the flow of Active power and later Reactive power flow was used. In both cases, the results become ambiguous when certain circumstances exist. Instances arose where a consumer was wrongly penalized for harmonics he did not cause. Therefore, in this paper novel techniques for identifying harmonic sources and quantifying the harmonic contributions from individual sources at a measurement point is developed, for a network with multiple nonlinear loads. The concept is derived from some salient characteristics of harmonic apparent power flow. A comparative analysis is carried out on the suitability of the use of active, reactive and apparent power flows for each of the harmonic components. Results obtained from the analysis show that the flow of apparent power proved to be the most promising in predicting the source of harmonics in a network. The results also show that harmonic apparent power gives the best representation of harmonic contribution, while the usual ambiguity in the commonly used indices derived from harmonic voltage or current is eliminated. A tool for determining penalty charges is also developed.

Keywords: harmonic source identification, harmonic contribution, harmonic apparent power, harmonic Source

I. INTRODUCTION the distortion. This includes the identification ompetitive electricity market of sources and quantification of level of engendered by the deregulated/ distortion injected by various end users in a C privatised Electricity Supply Industry network with multiple non-linear loads. The (ESI) has imposed the status of “commodity” ensuing procedure may be complex except to electric power. As a commodity, its price there exists a distinctive co-relation between must align with some standards of quality. A specific causes and effects of most major challenge is how to adequately define disturbances. Going forward, the proper economic indices capable of administration of future contracts between reasonably representing Power Quality (PQ) participants in the ESI must overcome this technical specifications. It follows that, the challenge. design of any penalty mechanism for PQ defaulters must incorporate procedures for The emerging regulatory framework apportioning responsibilities to the cause of proposed by the Nigerian Electricity

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Regulatory Commission (NERC) for Market apparent power is deployed, hence the name Participants (MP) includes two major S-Flow. A comparative analysis is carried out provisions; on the suitability of the use of active, reactive  Supply continuity as a fundamental issue and apparent power flows to identify and of quality of electricity supply service quantify harmonic sources at PCC, in a  Voltage level and shape at the Point of network of linear and non-linear load Common Coupling (PCC) as a structures. concerned issue of power quality. II THE “S-Flow” FORMULATION Considering that contemporary electricity The concept of the S-Flow method is hinged utilization technology consists mostly of on the characteristic flow of harmonic power electronic controlled devices which apparent power assumed to be in the are both harmonic producing and opposite direction to that of fundamental increasingly sensitive to PQ, it follows that apparent power. The marginal decrement in very soon, PQ specifications will become part harmonic apparent power (HAP) as it flows of Genco-Disco contracts. This implies that through network impedance is deployed to very soon, PQ issues will become matters of trace a harmonic source, measured at a given rigorous legal interpretation in arbitral/court metering point. It follows that a combination proceedings that obviates the need for of recent breakthrough in Global Positioning stringent technical description and Systems (GPS) and Smart Metering standardization. Technology (SMT) can effectively capture synchronized data from multiple points on In general, emerging economies such as an electrical network at relatively low cost Nigeria have not been successful in and high accuracy. This will provide an regulating the quality of power available in integrated metering technology that their grid networks. The reason for this can combines harmonic source identification, easily be attributed to unavailable Power Quality (PQ) monitoring with monitoring schemes and strategies that can conventional voltage, current and power effectively identify harmonic sources and measurements. The ability of the above equally quantify the harmonic contributions meter to identify harmonic sources in a by the identified sources in typical network potential multiple harmonic source network, with multiple non-linear leads. such as typical distribution networks, solves the challenge of accurately apportioning Furthermore, Harmonic current and voltage penalties to PQ distortion culprits. are the well-known indices in common use for quantifying harmonic contribution [1], Furthermore, harmonic power flow models [2], [3] – [9]. However, either or both of these for typical distribution networks have been indices present some level of ambiguity developed for quantifying harmonic because their respective magnitudes are contributions. Methods of deriving the dependent on network impedance. In this model are presented in the remaining part of paper, a unique technique called the S-flow this section. A tool for apportioning penalty method, has been developed for identifying charges on PQ bench mark defaulters is also harmonic sources and quantifying the developed in the sequel. harmonic contributions from individual sources for a network with multiple A. Harmonic Source Identification nonlinear loads. Here, the flow of harmonic

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Consider a simplified radial distribution Where network shown in Figure 1(a), where the Eh,pcc is the hth harmonic voltage source at the utility supplies power to multiple customers PCC; Eh,ci is the harmonic voltage source for through dedicated feeders. customer i; Zh,ci, Zh,c2, …,Zh,cm are the respective hth system impedances, It can be shown that the apparent power that comprising that of step-down transformer flows out from the customer i load is given in and network cables; i = 1, 2, 3, 4, …, m (1), Harmonic source is identified if where i = 1, 2,….., n. or (3)

(harmonic apparent power at PCC) < (1) (harmonic apparent power at source)

While the harmonic apparent power that is or absorbed by the PCC (utility side) is given by (4) (fundamental apparent power at PCC) > (2) (fundamental apparent power at source)

Figure 1(a): Utility network supplying multiple customer nonlinear loads

Figure 1(b): Equivalent circuit of the network shown in Figure 1(a)

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B. Quantifying Harmonic Contribution among offending customers using the ratio Using superposition principles, it can be of their respective harmonic power shown that the harmonic apparent power contributions. contributed by customer i to PCC from If the fixed utility charge for the net Figure 1(a) yields equation (5). harmonic power recorded at the PCC is (N/kVA/month),

The total penalty charge at the PCC is (5) (N /month) (7)

Harmonic contribution of utility to PCC is The penalty charge for each of the offending

customers is (6) (N/month) (8)

where, Where is the base power in KVA;

; is the average value of the magnitude of the net harmonic power at the PCC in p.u.; is the projection of the harmonic ; power contribution of customer i at the PCC onto the net harmonic apparent power at the

PCC; ; is the

penalty charge for customer i in Naira per is the angle between harmonic complex month; is the fixed penalty charge for the net harmonic apparent power at the PCC in powers contributed by customer i and N/kVA/month. harmonic complex power at the PCC; while is that for the utility. IV RESULTS AND DISCUSSION

Simulation studies were done in two III PENALTY CHARGE categories, each for harmonic source In order to effectively charge for penalties for identification and quantification of harmonic harmonic injections, new smart power utility contributions. The simulations were done in meters must be installed. The smart meters MATLAB/SIMULINK environment. In both will have the dual function of capturing both cases, the results obtained from the S-Flow the quantum and quality of power utilized method were compared with the results from by consumers. active power direction (APD) and reactive

power direction (RPD) methods. The penalty charge for harmonic injection is assigned to each offending customer using A. Simulation Results for Harmonic the ratio of the proposed power contribution. Source Identification This implies that the utility should provide a In order to have clarity in the demonstration fixed charge for the net harmonic power of the developed method, only three recorded at the PCC and share the net charge customers were considered in Figure 1. The

Innovation Solution in Engineering (ISIE) 43 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 current waveforms obtained when an ideal transformer is assumed to be the actual load sinusoidal 415V voltage source is applied to side. each of the customer loads are:

Table 1: Load Transformer’s Parameters Cusotmer1 Customer2 Customer3 Rating 33/0.415kV 33/0.415kV 33/0.415kV 12MW, 8MW, 10MW, 50Hz 50Hz 50Hz (9) Primary R=0.069pu; R=0.069pu; R=0.069pu; Winding L =0.8pu L =0.8pu L =0.8pu (10) Secondary R=0.069pu; R=0.069pu; R=0.069pu; Winding L=0.8pu; L=0.8pu; L=0.8pu; Magnetization Rm=500pu; Rm=500pu; Rm=500pu; Lm=500pu Lm=500pu Lm=500pu

The results obtained for customer1 when the network is simulated are given in Tables 2 – (11) 5. Table 2 contains the harmonic data captured at the point of common coupling Where I1= 1461A (rms) is the fundamental (PCC) – these data are same for all the three current. customers. Table 3 contains the harmonic data recorded at the primary side of the step- The parameters of the load transformers are down transformer that supplies power to given in Table 1. In the foregoing customer1. The data presented in Table 4 are discussions, the secondary side of a load the harmonic data captured at the secondary side of customer1’s step-down transformer.

Table 2: Harmonic data captured at the PCC Harmonic Current Current Voltage Voltage Current Voltage Phase Real Reactive Apparent Order (h) Harmonic Harmonic Harmonic Harmonic Harmonic Harmonic Angle Power, Power, Power, (%) Angle (o) (%) Angle (o) (A) (V) (o) PPCC (W) QPCC (VAR) SPCC (VA)

1 100.0 148.4 100.0 176.2 540.0 17940.0 27.8 8569466.7 4518167.2 9687600.0

3 25.9 39.4 7.1 0.0 140.0 1270.2 -39.4 137430.1 -112886.3 177849.2

5 16.8 36.7 7.7 0.0 90.9 1374.2 -36.7 100134.1 -74637.6 124890.4

7 3.9 0.0 2.5 200.4 20.8 441.3 200.4 -8622.0 -3206.5 9199.0

9 0.5 39.2 0.4 0.0 2.6 71.8 -39.2 144.1 -117.6 186.0

11 3.4 116.4 3.4 25.3 18.3 613.5 -91.1 -215.6 -11229.5 11231.6

Table 3: Harmonic data captured at the primary side of customer1’s transformer Harmonic Current Current Voltage Voltage Current Voltage Phase Real Power, Reactive Apparent Order (h) Harmonic Harmonic Harmonic Harmonic Harmonic Harmonic Angle (o) PP (W) Power, QP Power, SP (%) Angle (o) (%) Angle (o) (A) (V) (VAR) (VA) 1 100.0 149.2 100.0 176.2 181.8 17940.0 27.0 2906010.7 1480686.4 3261492. 0 3 39.1 65.0 7.1 0.0 71.0 1270.2 -65.0 38118.0 -81744.3 90194.9 5 31.0 23.6 7.7 0.0 56.3 1374.2 -23.6 70901.2 -30976.0 77372.4 7 20.3 0.0 2.5 200.4 37.0 441.3 200.4 -15288.3 -5685.7 16311.3 9 16.5 37.7 0.4 0.0 29.9 71.8 -37.7 1698.0 -1312.4 2146.1 11 0.7 0.0 3.4 25.3 1.2 613.5 25.3 675.7 319.4 747.3

Table 4: Harmonic data captured at the secondary side of customer1’s transformer Harmonic Current Current Voltage Voltage Current Voltage Phase Real Power, Reactive Apparent Order (h) Harmonic Harmonic Harmonic Harmonic Harmonic Harmonic Angle (o) PS (W) Power, Power, SS (%) Angle (o) (%) Angle (o) (A) (V) QS (VAR) (VA)

Innovation Solution in Engineering (ISIE) 75 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

1 100.0 149.2 100.0 172.4 14410.0 217.3 23.2 2878082.1 1233547.5 3131293.0 3 39.2 65.1 15.8 0.0 5647.3 34.4 -65.1 81789.8 -176201.0 194258.4 5 31.1 23.7 19.7 0.0 4475.7 42.8 -23.7 175528.3 -77051.6 191695.4 7 20.4 0.0 12.1 256.9 2939.6 26.3 256.9 -17547.5 -75405.8 77420.6 9 16.5 37.8 11.8 0.0 2377.7 25.6 -37.8 48172.8 -37366.7 60966.3 11 0.7 0.0 3.0 23.4 96.5 6.5 23.4 575.7 249.1 627.3 Table 5: Application of APD, RPD, and S-Flow techniques on customer1 APD RPD S-Flow h Ps-Ppcc (W) Ps-Pp (W) Qs-Qpcc (VAR) Qs-Qp (VAR) Ss-Spcc (VA) Ss-Sp (VA) 1 -661395.7 -15721.7 -236778.5 -105248.4 -674387.2 -15649.6 3 -2605.0 -837.2 -18952.3 -25082.5 19126.2 24486.4 5 192.3 -564.5 -19522.8 -21853.7 19512.1 21834.4 7 -625.8 -166.7 -9327.1 -9392.7 9348.0 9098.6 9 250.3 -110.9 -6178.6 -6200.8 6182.8 6050.4 11 13.9 -0.5 186.9 -13.8 -178.3 -7.9

The applications of APD, RPD and S-Flow observations show that the metering point methods on the data obtained for Customer1 affects RPD method. are summarized in Table 5. According to APD method, customer 1 injects 5th, 9th and Furthermore, the developed S-Flow method 11th harmonic to the PCC but absorbs the 3rd is applied on customer 1 load. According to and 7th harmonics, when the reference points the results presented in Table 5, it can be seen are the PCC and the transformer secondary. that customer1 generates harmonic 3, 5, 7, However, referring to the primary and and 9 but absorbs harmonic 11 when the secondary sides of the load transformer, the reference points are the PCC and the customer absorbs harmonics 3, 5, 7, 9 and 11. transformer secondary. The Table also shows These observations contradict the harmonics that similar results are gotten when the injection characteristics of customer1 as primary and secondary sides of the specified in (9). These also show that the transformer are considered. These metering point affects the results of APD observations conform to the harmonics method. generation characteristics of customer1 as specified in (9). They equally show that the Similarly, the application of RPD as specified metering point does not affect the results of in Table 5 shows that customer1 absorbs the developed method. harmonics 3, 5, 7 and 9 but generates harmonic 11 when the reference points are C. Simulation Results and Discussion the PCC and the transformer secondary. But for Quantification of Harmonic customer 1 does not produce harmonics 11 as Contribution specified in (9). Also when the primary and The developed complex/apparent power secondary sides of the transformer are technique for quanitifying harmonic considered, the results show that customer 1 contribution is tested on the distribution absorbs harmonics 3, 5, 7, 9, and 11. These network shown in Figure 1 when the number of customer loads is three as indicated in Figure 3.

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Figure 3: Equivalent circuit of utility network supplying three Table 8: Studied Cases  The respective value of the customers’ CASE 1 CASE 2 CASE 3 CASE 4 harmonic sources are presented in the following table 9. Customer1 Constant Constant Variable Variable source Table 9: Customers’ individual harmonic sources Customer2 Constant Constant Variable Variable Harmonic Harmonic Source source order, h Eh,c1(pu) Eh,c2(pu) Eh,c3(pu) o o o Customer3 Constant Constant Variable Variable 5 1.0∟50 1.2∟93 1.4∟45 o o o source 7 0.7∟50 0.86∟61 1.0∟23 11 0.45∟92o 0.55∟72o 0.64∟117o Network Constant Variable Constant Variable 13 0.38∟30o 0.46∟116o 0.54∟27o Impedance In Figure 3, it can be shown (using

Kirchhoff’s Current Law) that the Four case studies are examined as presented expressions for Vh,pcc and Ih,pcc are th in table 8. For cases 2, 3 and 4, only the 5 respectively: harmonic is considered. The following parameters and conditions are used for the simulation:

 h,u The network impedance Z is (13) represented by a series combination of 1- (14) ohm resistor and 1mH inductor  Customer1’s network impedance is represted by a series combination of 1- CASE 1: Steady-State Condition ohm resistor and 1.6mH inductor The determined harmonic contributions for  The netowrk impedance of Customer2 is each of the respective customers are represented by 1.5-ohm resistor in series presented in Table 10. with 1.6mH inductor  The network impedance of Customer3 is Observations represented by 2-ohm resistor in series  Table 3 shows that customer2 has the with 3.18mH inductor highest 5th harmonic contribution using  The magnitude of the background current index. However, customer1 has harmonic source in the utility network the highest 5th harmonic contribution Eh,u is assumed to vary randomly as in using voltage index. Meanwhile, the real case and is reprented by a normal developed apparent power based distribution of mean,µ = 0.1 and standard technique shows that customer2 has the deviation,σ = 0.02. highest harmonic contribution, followed  The network has unity base impedance. by customer1, customer3, and utility in that order.

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 For the 13th harmonic, customer 2 correspond to the relative amount of recorded the highest harmonic power harmonic power contributions contribution (47.89%) though it did not contribute the highest harmonic current The above observations suggest that voltage and voltage and current harmonic contributions are not  However, for the 7th and 11th harmonics, appropriate for quantifying harmonic the relative amount of current and contributions. voltage harmonic contributions

78 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Table 10: Harmonic Contributions at Steady State HARMONIC CONTRIBUTION IN HARMONIC CONTRIBUTION (pu) PERCENTAGE (%)

Harmoni TYPE c Order, h 5th 7th 11th 13th 5th 7th 11th 13th

Iu,pcc,x 0.003766 0.002895 0.000146 2.09E-04 3.11% 7.11% 1.95% 10.05%

Ic1,pcc,x 0.042772 0.013846 0.002614 7.75E-04 35.27% 34.02% 34.94% 37.21% Current Ic2,pcc,x 0.04587 0.015075 0.003099 0.000563 37.83% 37.04% 41.42% 27.02%

Ic3,pcc,x 0.028849 0.008888 0.001623 5.36E-04 23.79% 21.84% 21.69% 25.73%

Vu,pcc,x 0.014344 0.011645 0.001611 0.002837 3.18% 4.44% 1.60% 6.63%

Vc1,pcc,x 0.166993 0.09159 0.035259 0.015738 36.97% 34.95% 35.08% 36.76% Voltage Vc2,pcc,x 0.1561 0.102283 0.040259 0.013414 34.56% 39.03% 40.05% 31.33%

Vc3,pcc,x 0.114205 0.056518 0.023387 0.010821 25.29% 21.57% 23.27% 25.28%

Su,pcc,x 0.000276 4.72E-05 3.58E-06 6.88E-07 1.24% 1.29% 1.31% 1.32%

Sc1,pcc,x 0.00807 0.001266 9.18E-05 1.76E-05 36.69% 34.71% 33.47% 33.61% Power Sc2,pcc,x 0.009925 0.001699 0.000132 2.50E-05 44.57% 46.58% 48.09% 47.89%

Sc3,pcc,x 0.003997 0.000635 4.70E-05 8.97E-06 17.95% 17.42% 17.13% 17.18%

CASE 2: Only Utility Network Impedance scenario, the network impedance is changed Changes from 1+j1.571 to 1+j1.071 at time t=0.91 In this case, only the utility network second, and the variations of the harmonic impedance changes with time. The variations power contributions at the PCC are of the 5th harmonic power contributions at presented in Figure 4(b). It is shwon in that the PCC when the network impedance figure that the harmonic apparent power increases is shown in Figure 4(a). At time contributed at the PCC increased from that t=0.91, network impedance is changed from point instant onwards. These observations 1+j1.571 to 1+j2.571. It is seen that the conform to common sense prediction. A harmonic apparent power contributed at the reduction in network impedance should PCC by each of the customers decreases from induce a harmonic producing load to inject that time instant onwards. In another more harmonic power into the network.

0.012 Customer1

Customer2 0.18 0.01 Customer3 Customer1 Utility 0.16 Customer2 Customer3 Utility 0.008 0.14 0.12

0.006 0.1

0.08 0.004 0.06

0.002 0.04 0.02

Harmonic Power contribution at the PCC [pu] the at contribution Power Harmonic Voltage Harmonic contribution at the PCC [pu] the at contribution Harmonic Voltage

0 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Time[sec] Time[sec] Figure 4(a): Harmonic power contribution Figure 5(b): Voltage harmonic contribution when Zu increases with time when Zu decreases with time

78 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

0.012 Customer1 0.05 Customer2 Customer1 0.01 Customer3 0.045 Customer2 Utility Customer3 0.04 Utility 0.008 0.035

0.03 0.006 0.025

0.02 0.004 0.015

0.002 0.01 0.005

Harmonic Power contribution at the PCC [pu] the at contribution Power Harmonic Current Harmonic contribution at the PCC [pu] the at contribution Harmonic Current 0 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Time[sec] Time[sec] Figure 4(b): Harmonic power contribution Figure 6(a): Current harmonic contribution when the when Zu decreases with time network impedance Zu increases with time

0.25 0.07 Customer1 Customer1 Customer2 Customer2 Customer3 0.06 Customer3 0.2 Utility Utility 0.05

0.15 0.04

0.03 0.1

0.02 0.05

0.01 Current Harmonic contribution at the PCC [pu] the at contribution Harmonic Current

Voltage Harmonic contribution at the PCC [pu] the at contribution Harmonic Voltage 0 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Time[sec] Time[sec] Figure 5(a): Voltage harmonic contribution when the Figure 6(b): Current harmonic contribution when the network impedance Zu increases with time network impedance Zu decreases with time

The effect of changes in network impedance is also studied for voltage and current D. Effect of Phase Angle on Harmonic harmonic contributions. The results obtained Contribution are presented in Figures 5 and 6. As shown Plots of harmonic contributions against in Figure 5(a) when the network impedance phase angle of customer2 harmonic source increases at time, t=0.91 second, voltage obtained using voltage, current and apparent harmonic contribution will increase and power indices are respectively shown in when the network impedance decreases Figures 7, 8 and 9. As shown in Figure 7, the (Figure 5b), the voltage harmonic relative quantities of voltage harmonic contribution will decrease. However, Figures contributed by each of the customers and the 6(a) and 6(b), show converse relationship utility vary with the phase angle; one of the between current harmonic contribution and sources will record the highest contributor at network impedance. When the network a certain range of phase angle but will not be impedance increases, current harmonic the highest contributor at another range of contribution will reduced (Figure 6a) but phase angle. Similarly, the plots of current when the network impedance decreases, harmonic contributions against the phase current harmonic contribution will increase angle of Ec2 presented in Figure 8 show that (Figure 6b). These observation implies that the relative quantities of harmonic additional information is requried to contribution from each of the sources vary determine appropriate harmonic with the phase angle. These observations contributions when voltage or current suggest that the use of voltage or current harmmonic contribution to the PCC is used criteria for quantifying harmonics independently. contributions will be ambiguous in practical

Innovation Solution in Engineering (ISIE) 79 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 networks where the phase angles of at the PCC reduces to a minimum value is harmonic sources can change anytime due to called Cancellation Angle. varying operating conditions and combination of loads.

Figure 8: Current harmonic contribution versus Figure 7: Voltage harmonic contribution versus phase angle of customer2’s harmonic source phase angle of customer2’s harmonic source

However, the plots of the developed apparent power based harmonic contribution against the phase angle are presented in Figure 9. The figure shows that the relative quantities of harmonic contributions from each of the sources do not change as the source phase angle varies. It is seen that customer2 generates the highest harmonics, followed by customer1, customer3 and the Figure 9: Harmonic apparent power contribution utility (in that order) for all range of the versus phase angle of customer2’s phase angle. Similar relative quantities of harmonic source harmonic apparent power are obtained when the respective harmonic power contributions V. CONCLUSIONS are plotted against the phase angles of the It is shown in this paper that the flow of other harmonic sources. Customer2 always harmonic apparent power can be used to has the highest harmonic contribution. In identify a harmonic source. Unlike active and each of those cases, it is observed that reactive power flows that have inconsistent harmonic apparent power contributions from direction of flow, harmonic apparent power each of the sources concurrently reduce to a always flows consistently from the source of minimal value at a certain phase angle. For harmonic to any other part of the network instance, in Figure 9, the minimum harmonic which makes it a good tool for identifying a contribution from each of the sources occurs harmonics source. It has also been at phase angle 220o of customer2 source. This demonstrated that the developed harmonic suggests that the net harmonic power apparent power contribution index is ideal injected into a network by multiple harmonic for determining the respective individual sources can be reduced or totally eliminated load harmonic contributions to the net via tuning of the phase angle of one of the harmonics recorded at the point of common harmonic sources. Such angle of a harmonic coupling (PCC) in a network. The presented source at which the net harmonics recorded results show that the quantity of harmonics contributed by a source varies logically with

80 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 the prevailing changes in the network. The developed techniques can be used to identify harmonic sources and quantify their Mazumdar, J., Venayagamoorthy, G.K., contributions when multiple loads are Harley, R.G., & Lambert, F.C. (2006). connected to a point of common coupling. Echo state networks for determining The developed techniques also gave insight harmonic contributions from on how the net harmonics contributed by nonlinear loads. Proceedings of Internal multiple loads can be eliminated. Joint Conference on Neural Networks, Canada: Sheraton Vancouver Wall REFERENCES Centre Hotel, Vancouver, BC, 1695 – Mazumdar, J, Harley, R.G., Lambert, F.C., 1701. Venayagamoorthy, G.K., & Page, Ajami, A., & Bagheri, F. (2012). Estimating M.L. (2008). Intelligent tool for the harmonic contributions of utility determining the true harmonic and customer in a distorted power current contribution of a customer in system. ECTI Transactions on Electrical a power distribution network. IEEE Engineering, Electronics, and Transactions on Industrial Applications, Communications, 10(2), 217 – 226 44(5), 1477 – 1485. Fan, R., Tan, T., Chang, H., Tong, X., & Gao, Xu, W., Liu, X., & Liu, Y. (2003). An Y. (2013). A method for assessing investigation on the validity of customer harmonic emission level power-direction method for harmonic based on the iterative algorithm for source determination. IEEE least square estimation. Engineering Transactions on Power Delivery, 18(1), Science Research,5, 6-13. 214 – 219. Zhuo, Y., Wu, J., Tang, G., Hu, F., & Yu, Y. Xu, W., & Liu, Y. (2000). A method for (2010). Power monitoring device with determining customer and utility qualitative harmonic source harmonic contributions at the point of identification. Proceedings of Power and common coupling. IEEE Transactions Energy Engineering Conference on Power Delivery, 15(2), 804 – 811. (APPEEC), Asian-Pacific: Chengdu, 1 Dai, J., Zhang, P., Mazumdar, J., Harley, R.G., – 4. & Venayagamoorthy, G.K. (2008). A Farhoodnea, M., Mohamed, A., Shareef, H., comparison of MLP, RNN and ESN in & Jabbar Khan, R.A. (2010). An determining harmonic contributions improved method for determining from nonlinear loads. Proceedings of contribution of utility and customer 34th Annual Conference of IEEE on harmonic distortions in a power Industrial Electronics (IECON), distribution system. International Orlando, FL, 3025 – 3032. Journal on Electrical Engineering and Informatics, 2(3), 204 – 215.

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A TOTAL OPTIMIZATION OF THE ELECTRICAL POWER VALUE CHAIN: CHALLENGES, OPPORTUNITIES AND INTERVENTION STRATEGIES

Momoh, James A. Center for Energy System and Control (CESaC), Howard University [email protected]

ABSTRACT The optimization goal of today’s power grid is to get the maximum benefits from the new technologies in both hardware and software that will improve modeling, performance, reliability, stability, quality of service and electricity delivery. These technologies are to be applied to solve the total optimization problem of the electric power value chain. We understand that this word ‘optimization’ is just a metaphor. No one does real optimization in the power grid. It’s just a fashion statement, like the ‘smart grid,’ which just means we are smart people and we do our best. Progress in upgrading the grid has been slowed by such gross misconceptions as indicated at the Federal Energy Regulatory Commission (FERC) workshop in the United States of America, which explain in great detail how 70% of the electricity market in the US is managed by massive optimization programs located at a handful of Independent System Operators (ISO), such as PJM, NYISO , California ISO and MISO which gives specific orders to every aspect of the supply chain including generator, transmission and distribution has been demonstrated to show improved performance and then justify the investment made in modernizing and augmenting of the system with optimization technologies. The optimization technologies are supported by the integration of Plug-in Electric Vehicle (PEV), Flexible AC Transmission Systems (FACTS) devices, cyber security technologies, Internet of Things (IoT), power electronics and intelligent systems used for designing the automation functions to achieve improved performance. It is therefore relevant that the total optimization process discussed in the paper should be of interest to the research and development group at the Federal Ministry of Power, Works and Housing, Nigeria Electricity Regulatory Commission (NERC), FUELCOs, GENCOs TRANSCOs and DISCOs if they want to achieve the desired efficient electricity delivery mandate for an affordable, secured and sustainable power supply. Previous works in optimization methods for the power system have failed to provide a holistic solution to handle the system challenges under different conditions. For example, a failure in one of the levels in the supply chain, if not handled properly in time, will result in a malfunction of the interconnected systems. The question now is how we can effectively develop the optimization technologies that will guarantee the performance of the entire supply chain. This paper gives some highlights of the open challenges, important connections to the large needs of the FUELCOs, GENCOs, TRANSCOs, DISCOs and consumers and then provides appropriate synergy between the new optimization techniques that account for practical insights and reality of the integrated supply chain by including new advances in optimization techniques that can handle static and stochastic behavior of the grid. The artificial intelligence (AI) is used for handling the foresight and the adaptability of the system to other unforeseen conditions. New technologies for cyber security and new physical hardware are essential to achieve the maximum success for the survival of our endangered species. Furthermore, the use of communication subsystem such as the Internet of Things (IoT) in general are essential for achieving the global performance of the grid. For few illustrations we provide case study to demonstrate the potential of optimization technologies to handle some of the challenges in selected electric supply chain.

Keywords: Total Optimization, Computational Analysis, Energy Power System, Micro Grid, Power Supply Chain, Regulation and Innovation, Renewable Energy, Critical Technologies

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A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

I INTRODUCTION - OBJECTIVES OF THE ELECTRIC VALUE CHAIN One of the drastic steps gave birth to the ince last 20 years, several scholars and unbundling of the power sector and reform practitioners have reviewed [1] the process. Given the total Nigerian Electricity S cause for regular and adequate supply supply industry (with capacity of over 10,000 as the hall mark of a developed economy and MW and available capacity of over 6,000 they have been able to justify why reliable MW. Most generation is thermal based about power supply is an index for measuring the (83% of the total) while Hydro constitutes the social economic status of the citizen. It has remaining 27%. from three major plants. been demonstrated that proper policy, Several system challenges are identified and research, innovation, application of advanced reported by many reference papers [1][6] technology, appropriate regulation and which have summarized the problems as standards with optimized technology and follows: systems are all interconnected in determining a) Policy statement due to frequent change the efficiency of the modern electric grid as in policy leaders shown in FIGURE 1. In fact, any accurate b) Project execution which affects gaps in picture of policy issues in the developed planning and execution of different countries has drawn that their performance projects of the supply chain for energy is consistently supported by academic and delivery industry institutions to provide tools for the c) Inadequate generation, transmission and modern grid. distribution which include dilapidated ones, those in state of disrepair and The case is not so evident in others needing overhaul. developed/developing countries in Africa d) Inadequate gas supply due to unrest in such as Nigeria where the national Niger Delta region. Producers of gas development of its fuel, oil and gas, the are also unwilling to sell at a reduced refinery infrastructure, generation, price to power stations even with transmission, distribution and the customer subsidy from the Federal Government. subsystem are not well equipped for e) Financial challenges to complete capital achieving reliability, stability and efficiency. projects. The uncertainty in the This has led to inadequate power supply, regulatory environment is hampering incessant power outages, low generating private sectors investors from financing plants availability and high technical or non- electricity projects. technical losses that have characterized the f) In appropriate mapping of gas pipe lines case of Nigerian Electricity Industry. To and communication networks for the arrest these challenges, great deal of efforts grid system such as SCADA and by government has been proposed. measurement technologies.

Innovation Solution in Engineering (ISIE) 83 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Figure 1: Modern smart grid system

II REGULATORY COMMISSION ROLE III INFRASTRUCTURE CONSTRAINTS IN THE ELECTRIC SUPPLY CHAIN FOR ELECTRICAL SUPPLY CHAIN To ensure the efficiency, affordability and a (CHALLENGE) coordinated supply chain, the Nigeria Nigeria has over 13,000MW of installed Electricity Regulatory Commission (NERC) power generation capacity of which 8,000 was established to serve as the foundation of MW is mechanically available. Less than restructured power sector policy with the 4,000 MW is being dispatched on average following oversight: over the last 2 years due to constraints in gas a) To regulate tariffs and the quality of supply, electricity transmission, and service, distribution. As a result, the lack of constant b) Oversee the activities of the industry for electricity supply has discouraged efficiency, consumers’ willingness to pay and driven c) Institution and reinforcement of the industries to pursue off-grid alternatives. The regulatory regime. resultant is an inherent shortfall in the tariff d) Licensing of generation, distribution, and the accrued sector cash deficit. The transmission and trading companies infrastructure constraints across the value that result from the unbundling of chain can be broken into four components: (i) NEPA, Fuel (Predominately Gas), (ii) Generation (iii) e) Legislative authority is also included to Transmission and (iv) Distribution. determine the conditions for issuing of licenses, provision relating to public A. Fuel Company (FUEL-COs) policy about fuel supply, Gas is the predominant fuel for power environmental laws, energy generation in the Nigerian power sector conservation, management of accounting for 83-% of the installed capacity resources, promotion of efficient of 12,000 MW with available capacity of 7,200 energy, MW as of December 2016. f) Promotion of renewable energy. a) Inadequate gas pipeline infrastructure: g) Providing a legal basis with necessary The capacity of the gas pipeline authorization and regulating technical infrastructure is insufficient to reliably market rules and standards. meet the gas demands of the existing power plants operating at the full installed capacity. Although trunk line

84 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

capacity is nominally sufficient there is must consider constraints such as availability need for continued investment to of gas and natural resources as well as wind reinforce the network and overcome sun light for solar generation. Availability of local bottlenecks. resources for ancillary services and network b) Gas supply constraints and vandalism: constraints should be considered. Most of the gas supplied to the power plants are on a reasonable best Recent work in optimization algorithms endeavor basis. This has been include adaptive foresight, and they are compounded by power producers’ derived from next generation optimization large payment arrears that it is unable such as evolution programming methods to settle (total gas supply indebtedness adaptive critics, ANN and its hybrids. of power plants from January 2015 to Research work that includes real time December 2016 is NGN155 billion information and co-optimization of the (US$500 million)). As such supply has renewable energy resources under been erratic and low resulting in uncertainty need advance optimization 1,400MW of constrained generation. technology for a total optimization of the Vandalism on oil and gas delivery entire generation resources for the supply infrastructure has also shut down gas chain. References [3][7][8] are available to be production which resulting in another adapted as best practice in this area. 2,900MW of constrained generation in recent years. C. Transmission Company (TRANS- COs) B. Generation Company (GEN-COs) Transmission: While the transmission Some generating units are out of service due systems are managed to evacuate a record to lack of relatively minor repairs. Some 5,074 MW in the Nigeria supply chain as on power plants have been unable to undertake February 2, 2016, the system is operating well these minor repairs and/or required below international reliability and security maintenance due to lack of funding. Minor standards. There were six major system repairs and maintenance, combined, can collapses in 2016. Frequency and voltage unlock up to 1,700 MW of existing installed recordings often exceed established norms. generation capacity for dispatch. These are System collapses when not caused by relatively easy fixes that can increase the generation outages due to gas pipeline optimized capacity at minimal costs. vandalism were are primarily because of inadequate maintenance of outdated After all, the better, more intelligent equipment and lack of a comprehensive and optimization method could be worth modern SCADA system to have real time millions of dollars and decide whether we data with ability to manage in real time can make a profitable transition to operation and control for an optimum renewables rather than using central performance. generation system with its related supply chain policy issues. Overall, the GEN-COs Different transmission networks research optimization technology should consider activities have been done by different efficiency, sustainability, reliability and researchers which led to new policy and climate change. Optimization techniques to design changes. handle the production cost and loss minimization during unit commitment (UC)

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To optimize the renewable energy resources, electric power supply chain which such as wind and solar generation with consequently has affected the financial power electronics devices, hardware and viability of the entire value chain. The sector software needs to be integrated in the ATC&C losses are reported to be extremely network performance analysis using high averaging 54.3% in 2016 versus 32.1% optimization technique that will provide the projected in the tariff methodology. There technical - economic benefit analysis by has been no significant investment in loss a) Coordinating the generation and the reduction while remittances to Nigeria bulk transmission energy trading NBET and/or the Market b) Balancing between the coordinated Operator have been low. Renewable Energy Resources (RER and the Central generation with network All key performance indicators have on availability average worsened between 2014 and 2016. Billing and collection efficiency average 80% The limitation of RER and their uncertain and 51% respectively in 2016. Average natures must be studied in terms of their Technical Commercial and Collection impact on balancing the power mismatch (AT&CC) losses have worsened from an between input and output. How to overcome average of 52.1% in 2015 to 54.3% in 2017 and barriers such as political, social, economic it is highly unlikely that the distribution and limited manpower must be considered companies will meet their loss reduction in the optimization method used. This can performance targets as per Bureau of Public be solved using the hybrid of optimization Procurement (“BPE”) Performance and intelligent system technique with other Agreements. The power quality in smart devices. distribution network and the necessity to modernize the current system by introducing D. Distribution Company (DIS-COs) power electronic based devices and new Distribution constraints: Discos currently switching devices need to be considered. face constraints at the interfaces with transmission and at various other points in The optimization approach which include their respective networks. There is need for linear and nonlinear programming, quadratic demand-based distribution investment from dynamic programming, stochastic analysis using a bottom-up approach to be programming, evolution programming such able to study the benefit from the increased as ANN, Fuzzy logic, particle swarm, Ant generation/transmission capability. The colony, Genetic optimizations techniques, required system configuration could include adaptive and reinforcement learning and additional distribution lines and substations, their hybrids must be identified as reconfiguration of the existing distribution appropriate for handling the challenges network, including re-conducting to reduce posed in each of the sectors making up the technical losses and upgrading of electric supply chain where prediction of distribution transformers. uncertainty and foresight is need for optimal solution. The viability of the Discos is key to the long- term viability of the power sector. The New Internet of Things (IOT) need to be operational and commercial performance of developed to increase communication. the distribution companies since privatization has been poor in the Nigeria

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of the supply chain. It will also include new E. Customer Company (Custom-COs) hardware and control devices and monitors. These include commercial and residential Each of them is discussed in this section of users. The type, efficiency of equipment, the paper. metering and actions to ensure that ATC&C losses are minimized need to be considered. A. Renewable Energies: Storage and The Optimization technology will include Control advanced optimization technique based on The use of renewable energy sources real time data with ability to predict and presents new challenges for distribution handle variable control in the optimization networks and individual power consumers. process as part of the value chain. Again, we It affects availability of supply and overall suggest using stochastic optimization grid stability. For renewable energy, storage technology [10] to provide performance of is key to reduce power fluctuations, enhance different contingency and still produce the system flexibility, and enable dispatching acceptable quality of services. of the electricity generated by variable renewable energy sources such as wind and Integrating the results of the coordinated solar. optimization of the sub systems of the entire electric supply value chain presented is On the integration of Renewable Energy shown in the simple one-line diagram. Resources (RER) the experience of countries such as China on the related cost and the The existing problems and challenges are measures taken to minimize cost must be listed for each section. The available studied. Materials must be investigated, and technologies are given as the possible local resource-based materials must be solution plan. Solution for challenges in each exploited to break through the RER section is provided as an example. The open technology. This will create opportunities in questions state the tasks in future that will entrepreneurship in renewable electricity improve the supply chain for optimum generation, discussed further in [3] Nigeria electric power delivery. The competition between solar farms based The critical technologies for achieving the on solar cells (PVs) and solar farms based on total optimization are discussed in the next solar thermal power has become more several sections. challenging. For example, Chile has accepted a Power Purchase Agreements (PPA) at IV Critical Technologies: To support total under 3cents per kwh from a PV solar farm, optimization of the grid of Tomorrow but still relies much more on solar thermal Technologies include good software that can “power towers” at about 8 to 9 cents (even in handle stochastic parameters and the world’s best, lowest cost site), because of measurements needed in computing the the storage issue. optimization algorithm of each of the sectors

Innovation Solution in Engineering (ISIE) 87 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Fig.2. Depicts the objective of the total Optimization and the Nigerian Electrical Power Value Chain

In Brazil for instance, New connections lower resolution to the current life or death cost for solar power [3], but this has not conflicts [2][11]. happened partly because of legal/political risks and partly because investors Deregulated power grid creates a anticipation that manufacturers of PV solar competitive market for customers to choose cells (most especially the Chines) would which utility company to supply them migrate in droves to solar power electric power. Power quality is one of the technologies. technical issues of deregulated power grid. New power electronic devices are used to In climes like Nigeria, local content resolve the technical issues of power system development to support optimum and improve power transfer capability. performances for the renewable and storage Examples are the Flexible AC Transmission technology is recommend. Here we propose Systems (FACTS), Mobile Electric Vehicles an Intelligent Hand-Held Controller (IHHC) amongst others and other power electronics for optimizing the power output in the devices can be used for fuel security, integrated systems which will be embedded protection relays. as part of the total optimization scheme for the supply chain. C. Automation Functions for Distribution Networks B. Power Electronics-New Power Automation functions are used to improve Electronics, Motors and Fuel Flexibility the system in following aspects Real energy experts understand that fuel a) The quality of service transportation and security is a more urgent b) The reliability and stability of power issue to tackle than electricity supply in itself. supply As such, in most nations of the world, c) The pricing of electricity including the US [11].concerns about oil have d) Demand response grown larger and larger as a great e) Loss management complicating factor in international f) Operation cost in modern power grid. relations[2]. Greater fuel security and g) Reconfiguration, restoration, voltage/ Var diversity could be crucial in helping the control, load frequency control and nations of the world find more of a win-win, corresponding customer service.

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components in the development of IoT. In Automation functions for different levels of this, devices, in such a way that terminals the supply chain must be defined and and connections will be given unique appropriate optimization and control identifiers that can realize the automation of methods developed. Furthermore, data transformation even without human-to- communication levels should be defined. human and human-to-computer contact. This may include Internet of Things (IoT) to identify or monitor the health of the different A. Cyber Secured Communication System components in power system. The system Cyber secured communication system is now operator then has full control and prediction a global problem, since the cyber-attacks are ability to recommend real time what action automated and distributed. That means to take to counter any attack in the system. coordinated actions with distributed controls. For power network, the The above can be facilitated by the optimization of the energy supply from the integration of wireless communication and generation to the end users requires sensing devices. For each automation intercommunication between controllers in function, cost benefit analysis will be different levels. Due to the importance of required. A new research direction which power grid, the preventive actions against includes both intelligent systems with control attacks therefore have to be decisive. The optimization communication, co- next question will be the effective tools to optimization and co-simulation to handle prevent attacks in different scenarios for dynamic and stochastic behavior of the different products since for every product at supply chain of the power system is every stage of the lifecycle needs to be cyber proposed. Current work by [3] is a good secured. place to start. There are good reasons for providing cyber V Communication and IoT for optimized physical protection in the past, but as of now, electric supply chain more and more massive leaks ([2] and The “new AI” is just one element of a beyond) make the old strategy non- massive transformation moving very quickly sustainable. in the information technology (IT) industry, and in the industries affected by it B. Total Optimization Tool Using (essentially the entire world economy). For Intelligent Systems several years now, there has been general One of the available optimization tool is the agreement that we are moving from the old intelligent system. The intelligent system can Internet to a new IoT, which will control be applied to all the sectors of the supply every vehicle (civilian or military), every chain. For example, smart meters, plug-in factory, generator, household, building, etc. electric vehicles, digital computers, digital and have impact on everybody on earth, in cellphones substations and independent an integrated way. Major companies have operation centers can all have the build-in been spending many billions of dollars to intelligent system which shows the great support their diverse and clashing visions of potential of the tool.. Artificial Intelligence is what this new IoT will look like [12]-[17]. often used in intrusion detection. However, “brains” alone are not enough to protect us The objective of the optimizer of electric from fatal viruses or malware. There is value chain is to integrate all these

Innovation Solution in Engineering (ISIE) 89 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 therefore urgently need a new kind of wind, Solar, Geothermal, tidal and others immune system as discussed in [2]. [12]. There is growing risk that an organized enemy could launch a massive attack, totally Policy maker and regulators must realize that different from what the usual hacking total efficiency achievement and advance in security system had ever picked pick up. power system is a gradual change. Advanced These threats are present in the electrical and innovative optimization technologies networks on the resilience and survivability must be considered in planning and of the electric power supply chain. The very operation of power system. Investment made best work in power system does recognize on automating the system and adding that unbreakable operating systems are intelligent equipment such as Phasor important for the supply chain and that Measurement Units PMUs and Automatic major new efforts would be needed to Meter Instruments (AMI) is a step towards achieve the above. realizing an efficient system when included . in the new and next generation optimization VI Opportunities for Total optimization tools. Major work in the design and of the grid including Policy and implementation of such embedded system regulation requirements include: Deregulation in power industry has the a) Accurately integrating and coordinating objective of facilitating the development of a of technologies to the meet load competitive electricity market. A competitive demand market allows users to select the utility b) Regulations issues to ensure system company or generator that will provide the reliability and stability are within electric power supply. This selection is acceptable limits. normally done based on the electricity price c) Enforcement of system efficiency within and the quality of service. The regulator of certain limit by ensuring that the power systems must work towards a appropriate optimization technologies common goal to support the new competitive are used by each of the sectors of the energy sectors, available resources and supply chain. customer rates. Competitive sectors can be d) Ensuring control system actions, proper created by introducing cost or market-based pricing and market structures are used encouragement mechanism for efficient to achieve total optimization of the operation of the grid. supply chain. e) Further an optimized control of new Policy makers and regulators should give regulation proposed to the supply emphasis to clean and affordable energy of value chain and enforcement of same the future, promotion of innovative using the state of the art technology technologies, grid security, customer which will meet the common benefit of requirement, and advocacy of smart energy the Disco and customers under the infrastructure. Experiences of different watchful eye of the regulators. countries such as US must be considered as a f) Enforcement regulations using best benchmark to study how they realized an practice based on new technology that efficient and smart power grid. In US, Feed will lead to the development of in Tariffs (FIT) policies are implemented to optimized grid. support renewable technologies such as

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VII CASE STUDIES FOR EACH OF compressibility factor. λ(qj) is the THE PROBLEMS (OPEN QUESTON Darcy friction factor. AND SOLUTION)  Simulation  State equation A. FUEL-COs Case 00 Auc  t  In Nigeria, the problem of gas pipelines can AqGuq 0(,)0 be solved by the introduction of advanced (2) power electronic device for monitoring and  This is a non-linear system. Like sensing potential vandalization of fuel power flow calculation, it can be pipelines. Also, the economic dispatch and solved by iterative algorithm. scheduling problem needs to be studied. Where A is incidence matrix of

the graph. u is column vector of n Take gas for example, the controllable components. q is the column elements in gas transmission network are vector of e components. compressor stations and control valves that are connected via pipes. The objective of  Optimization optimization can be the minimization of self-  The objective is to minimize the self- consumption in compressor stations. The consumption in the compressor optimizer can be designed in the following stations by modifying the steps. compression ratio at the station  Modelling and other parameters.  Topology of the network: direct  The constraints come from physics graph, G = (N, E) where N is the set and security of supply aspects. of n nodes, E is the set of e edges  Integration of various optimization  Mathematical model can be deduced techniques and intelligent systems from the Navier-Stokes equations can be used to solve such a for compressible flows problem . The pressure loss equation represents

the head loss of a pipe B. GEN-COs Case Guuq(,,)  jini jfin( jj)( ) For generation companies in Nigeria,

16LRj inadequate generation capacity and Zuqqq(,) (1) 25 aaajjj   maintenance is the greatest challenge.  Dj Generation companies should consider the 2g ua HHfin( jini )( ) j  following aspects in the generation chain to R a Zu aa,  increase the generation. For the fuel used for generation, fossil fuel and gas are the two  Where uini(j) and ufin(j) are the square pressure at the beginning and the main choices. The energy conversion efficiency can be improved from both end of the pipe. Hini(j) and Hfin(j) are the heights at the beginning and mechanical and electrical sides. As for the generation unit itself. The Automated the end of the pipe. qj is the mass Generation Control (AGC) can be introduced flow of the pipe. θa is the average absolute temperature. L and D are in response to the change of load. On the the length and diameter of the electrical side, the technology improvement pipe. g is the gravity acceleration. can be applied with co-optimization control algorithm for RER and the cooperation with R is the gas constant. Z(ua,θ) is the

Innovation Solution in Engineering (ISIE) 91 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 the load forecast analysis to mitigate the Nb (()()),fPfQ12kDKkDK  fluctuation of output.  min k1 (3) Nb PPQQGDGD,,, The technologies or algorithms for these fPfQ()()   12kGkkGk  challenges are k1 a) Power electronics devices for automated voltage and frequency control Where PG, PD is the real power generation optimization and demand. QG, QD is the reactive power b) Energy storage device including generation and demand. batteries, super capacitors, and PEVs which can serve as an energy storage Power flow constraints, transmission line device as well in the new grid. constraints, bus voltage constraints, c) The hybrid between classical generation constraints, and dispatch-able optimization method and AI method load constraints are included in the are to be included in the total optimization and other intelligent systems optimization of the grid. and devices.

Take the last case for example, the objectives The Unit Commitment (UC) is another major of the optimizer for GENCOs can be problem for CENCOs. The mathematical minimizing for both fuel cost and form of the problem is environmental impact, minimize power loss 1. Objective function Tn and improving power quality etc. Based on ttttt min()( )(,)FiGiisiiGii PxFt xF Px the current optimization method, new ti11 elements, such as real-time calculation, co- (4) optimization, cloud storage and remote 2. Constraints access can be added to improve the a. Load balance equation efficiency, sustainability and reliability of the n PxPtTttt  1,2,, power system from generation side.  GiiD i1 (5) b.Generator power output limits ttttt xiGiGiiGi PPxminmax PtT , 1,2,, (6) c. Power reserve constraint n t t t  PGimax x i P D  P R , t  1,2, , T i1 (7) d. Minimum up-/down time Figure 2 GENCO case ()()UTupup 0, xxtT tt  in1,2,1 , , 1,2, , t1, i iii ()()UTxxtTdown 0, in down  1,2, tt1 , , 1,2, , For example, if the objective is to maximize t1, i iii the deliverable capacity from GENCOs. The (8) objective function is where : Start-up cost of unit i at period t : Power reserve at period t

92 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

: Minimum uptime for unit i in The penalty factor γ at kth generation is hours defined as : Minimum downtime for unit i in 0 log(1)k (12) hours : Number of consecutive uptime The accuracy and speed of convergence is periods until period t, measured decided by the penalty faction, γ. in hours Substituting the main objective function () : Number of consecutive downtime into (),

Tn (13) periods until period t, measured ttt ()()(xFPxFt ) x iGiisii ti11 in hours 22  Tnn CPPxCPPPxttttttt 12maxDGiiDRGii 2 iii111 The Particle Swarm Optimization can be n tttt  FPxFtiGiisiii()( ) xx implemented to unit commitment problem. T i1   2 2  Tnn  The constraint violation measure for t1 CPPxCPPPxttttttt 12maxDGiiDRGii  2 i1 ii11 the equality and inequality constraints are  defined as C. TRANS-COs Case 1 rm 22 The islanded system problem is considered uij()(())(())xgxhx  (9) 2 ij11 in Nigeria, since not all the area has been covered by central generation systems. There where are still many islanded grids in the rural area : The magnitude of the violation of due to poor construction plan. As for these the ith inequality constraint islanded cases, the pricing problem, the : The magnitude of the violation of protection problem, the maintenance problem and other problems must be solved the jth equality constraint by the application of advanced technologies, r : The number of inequality such as multi-phase performance constraints measurement, critical optimization of the m : The number of equality constraints existing transmission system, mobile

generation units to handle contingency cases. The total evaluation of an individual x is These technologies are not only useful for the defined as current existing problems but also can be ()()()xxx   (10) fu adapted in modern power grid with sufficient transmission capacity. where γ is a penalty parameter of a positive constant for the minimization problem. As for the United States, for example deregulated power markets have already Then the objective function of UC is been set up in many states. In the formulated as the main objective function deregulation process of power grid, the which is the total production cost plus the objectives are to maintain system reliability power balance and spinning reserve as as well as create a competitive market for inequality constraints. maximizing the overall social welfare. ()(,)x F Ptt x Gi i Transmission system acts as a backbone in 22(11)  T n   n  C Pt  P t x t  C P t  P t  P t x t this type of system. The transmission system 2 1D  Gi i  2  D R  Gi max i  i1 i  1   i  1  can consider all the above factors that are discussed above. To solve the standard

Innovation Solution in Engineering (ISIE) 93 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 transmission optimization problem with transmission line or a cyber-attack on the stability and congestion consideration. The control center. All in all, the power quality is general procedure is summarized as follows the toughest challenge for DISCO in Nigeria. Step 1: Set “would be committed The technology gap is huge. However, generation” for GENCOs with setting up the Internet of Things (IoT) can be relative data and ratings a starting point for design of smart meter for Step 2: Set the loads to their maximum each home to increase the power quality and value power stability. Step 3: Do optimal performance studies accounting for stochastic With the help from IoT, distributed optimization method. calculation can be conducted in the Step 4: Check the line and transformer intelligent system in each micro energy constraints. If there is any violation, source. As a result, the smart micro grid go step 5, otherwise go step 6. system can be set up to improve the Step 5: Hold the overloading line/ resiliency of the power grid. transformer at limit Step 6: If all line/transformers have been E. Customer COs Case investigated, output the optimal In Nigeria, the modelling of the load from solution of scheduled units and end user is also a tough challenge due to the price implication. lack of data acquisition in most areas. Electricity stealing is another issue the If the transmission system planning Distribution Company need to worry about. problems should include more objectives in The solution may also come from smart addition to the objective of the minimization metering for monitoring electricity usage for of the construction cost while avoiding each home. The poor modelling of the end overloads, then it becomes a multi-objective user load will result in inaccurate load optimization problem. Various multi- estimation and forecast. Poor load forecast objective optimization method is discussed can also affection the generation side by in following references [23][24]. increasing the error between forecast value and actual value. The user end protection D. DIS-COs Case needs to be applied physically and from In Nigeria, there are many existing cyber security attack. challenges for the distribution companies as well. First is the low voltage problem due to New Optimization technologies and the overload condition in densely populated innovative algorithm for end users can be the area. Secondly, the unbalanced distribution tools for load profile optimization. The and lack of adequate communication optimizer can be summarized in the technology result in the decrease of customer following four steps. satisfaction. Due to the poor state of the Step 1: Stochastic modelling for end user distribution network in Nigeria, the energy load loss during the distribution is extremely high Step 2: Setting up electricity cost and compared to modern distribution grid in system stability multi-objective developed country. Since there is less or no optimization problem communication, the network also suffers Step 3: Perform OPF to solve the non-linear from the attack problem. The attack can be a problem. physical attack the distribution line

94 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018

Step 4: Investigate each load profile for Industry in Atacama. safety consideration www.werbos.com/Atacama.pdf, Step 5: Each of the steps will consider using prepared for Solar Energy Research new advances in optimization and Consortium of Chile and Enersol communication controls with 2016. devices to be included in achieving [4] www.werbos.com/IT_big_picture.pdf the optimum performance of the [5] Onochie U.P, Egware H.O, and electric supply. Eyakwanor T.O, The Nigerial Electric Power Sector (Opportunities and VII CONCLUSION Challenges), Journal of The objective of this paper is to provide an Multidisciplinary Engineering Science overview of the power supply chain. The and Technology (JMEST), Vol. 2 Issue challenges and opportunities are explained 4, April – 2015. and analyzed and listed in each of the [6] I Okoro, O I Okoro, Power sector reforms sections. in Nigeria: opportunities and challenges, Journal of Energy in Communication and cyber security besides Southern Africa Vol 18 No 3 , August these technologies as systematic solution 2007. plan needs be prepared by the system policy [7] P. Maghouli, S. H. Hosseini, M.O. Buygi maker. and M. Shahideour, A Multi Objective framework for Intellectual thinking must be done to get the Transmission Expansion Planning in total picture of the supply chain. Deregulated Environment, IEEE Transaction of Power system, May Finally, with collaboration to other systems 2009. such as economic and politics, the total [8] Amir Motamedi, Hamidreza Zareipour, optimization can be realized for each section Majid Oloomi Buygi and William D. of the power supply chain from fuel to end Rosehart, A Transmission Planning user. Framework Considering Future Generation Expansions in Electricity REFERENCES Markets, IEEE Transactions on Power [1] Werbos, P. J. (2011). Computational Systems, vol. 25, No. 4, November intelligence for the smart grid-history, 2010. challenges, and opportunities. IEEE [9] Simon K. K. Ng, Student Member, IEEE, Computational Intelligence C. W. Lee, Student Member, IEEE, J. Magazine, 6(3), 14-21. Zhong, Member, IEEE, A Game- [2] Werbos, P. J. (2017). New technology Theoretic Approach to Study options and threats to detect and Strategic Interaction Between combat terrorism. In Identification of Transmission and Generation Potential Terrorists and Adversary Expansion Planning, IEEE Planning: Emerging Technologies and Transactions on Power Systems, 2006. New Counter-Terror Strategies, [10] H. Shuai, J. Fang, X. Ai, Y. Tang, J. NATO/IOS, 132, 34. Wen and H. He, "Stochastic [3] Werbos, P. J., & Int Control, L. L. C. Optimization of Economic Dispatch (2016). Urgent Investment for Microgrid Based on Approximate Opportunity To Scale Up Solar Dynamic Programming," in IEEE

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[16] Michael Chui, Markus Loffler and generation source Roger Roberts, The Internet of https://www.eia.gov/todayinenerg Things, McKinsey, March 2010, y/detail.php?id=34652 www.mckinset.com/insights/high [23] R.E. Steuer. “Multiple criteria _tech_telecoms_internet/the_inter optimization: theory, computations, net_of_things and application” (John Wiley & Sons, [17] Simona Jankowski, James Covello, New York, 1986) Heather Bellini, Joe Ritchie and [24] Y. L. Chen and C. C. Liu, Daniela Cost, IoT primer: the Internet "Multiobjective VAr planning using of things: making sense of the next the goal-attainment method," in IEE mega-trend, Global Investment Proceedings - Generation, Research, Goldman Sachs Transmission and Distribution, vol. 141, no. 3, pp. 227-232, May 1994.

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[25] Yao, Yin, Wenzhong Gao, and Yan Li. https://www.eia.gov/consumption "Integration of PHEV smart charging / method to hybrid wind [29] Momoh, James. Smart grid: power/battery storage system." North fundamentals of design and analysis. American Power Symposium (NAPS), Vol. 63. John Wiley & Sons, 2012. 2013. IEEE, 2013. [30] Momoh, James A. Adaptive stochastic [26] January’s cold weather affects optimization techniques with electricity generation mix in applications. CRC Press, 2015. Northeast, Mid-Atlantic [31] Momoh, James A. Electric power https://www.eia.gov/todayinenerg system applications of optimization. CRC y/detail.php?id=34632 press, 2017. [27] Y. Yao, W. Gao and J. Momoh, [32] Momoh, James A., and S. Surender "Performance optimization and Reddy. "Review of optimization evaluation of V2G in regulated and techniques for renewable energy deregulated microgrid," 2017 IEEE resources." Power Electronics and Conference on Energy Internet and Machines for Wind and Water Energy System Integration (EI2), Applications (PEMWA), 2014 IEEE Beijing, 2017, pp. 1-6. Symposium. IEEE, 2014. [28] Energy consumption estimates by sectors

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Hierarchical Bayesian Parameter Estimation of the Reliability of Nanoscale Metallic Oxide Semiconductor (MOS) Devices

Wilkistar Otienoa, O. Geoffrey Okogbaab aDepartment of Industrial Engineering, University of Wisconsin-Milwaukee, WI, USA bFederal University, Wukari (FUW), Nigeria & University of South Florida, Tampa, FL, USA

ABSTRACT The successful fabrication and incorporation of metallic oxides into semiconductors has been a major milestone in the electronic industry. To increase the performance of micro processors, the number of transistors crammed into each micro processor chip has progressively increased. This has been made possible by the reduction (scaling) of transistor dimensions among which is the dielectric thickness. The reduction of the dielectric thickness has had severe reliability and performability implications and challenges, so it is imperative that models that predict dielectric reliability be developed. In this research, we present an integrated three-stage hierarchical Bayesian model for dielectric failure, to estimate the unknown parameters of the underlying reliability structure of a high-k Metal Oxide semiconductor (MOS) device failure. Hierarchical Bayes models have successfully been used in public health and related research, so we extend this application to dielectric failure analysis by incorporating the current MOS dielectric failure physics model into the failure probability function in the form of the Arrhenius-Weibull model. Previous statistical analyses of dielectric failure have used either classical parametric or nonparametric statistical models. The proposed physics of failure model gives meaning to the shape and scale parameters of the two-parameter Weibull distribution, and is used to estimate the dielectric characteristic life, the failure rate and acceleration factor, all of which are necessary to predict the life of a dielectric thin film. Markov Chain Monte Carlo methods are used to obtain the posterior results which are finally used to obtain the dielectric mean time to failure (MTTF). The Bayesian results are compared to the results from the maximum likelihood (ML) and least square error (LSE) estimation techniques and shown to have relatively narrower predicted MTTF confidence interval.

Keywords: Bayesian hierarchical model estimation Metallic Oxide Semiconductor (MOS) Nanoscale reliability Markov Chain Monte Carlo (MCMC) simulation WinBUGS

1. BACKGROUND: DIELECTRIC micro processor industry recorded a PERFORMANCE AND BREAKDOWN progressive increase of the number of The success of the electronic industry has transistors on a chip from 10,000 in 1975 to been attributed to the incorporation of over 1 billion transistors on the same chip transistors into micro processors. In the size in 2011 (Hicks et al., 2008). Further more, paper, Cramming more Components onto today’s top-of-the-line microprocessors have Integrated Circuits (IC), Moore noted that the circuit features that are around 14 objective of miniaturization is to include as nanometres, an indication that the many electronic components as possible in exponential miniaturization has surpassed the smallest space possible and with the least Moore’s predictions (Waldrop, 2016). The weight implications as possible (Moore, increase in the number of transistors on a 1975). He postulated that the number of chip has been made possible by the transistors on an IC would double every two progressive reduction (scaling) of transistor years (Moore, 1975). In recent years, the dimensions among which is the dielectric

98 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 thickness. Dielectrics are insulating materials (Degraeve et al., 2000), (Linder and Stathis, by definition (Wu et al., 2009) and are used in 2004). This multistage defect-driven most Metallic Oxide Semiconductor (MOS) breakdown process follows this sequence: (i) devices to keep charge carriers from flowing initially, defects are generated at a rate that through the gate electrode as shown in the gradually increases with time, (ii) when schematic representation of a MOSFET in enough defects align to form a conduction Figure 1. Before and during the 21 path that brigdes dielectric thickness, the century, was used as the dielectric dielectric breaks down and the current leaks material. However, as the scaling limits of through it causing an abrupt increase in the dielectric thickness was reached, newer gate current, and (iii) whether the dielectric high-k materials, with relatively higher becomes completely conductive or remains dielectric permittivity than were quasi-insulating depends on the surrounding developed and incorporated into MOSFETs. stress levels (electric field) (Alam et al., 2001), (Degraeve et al., 2005). The leakage current leads to increased stand-by power dissipation within the dielectric thereby decreasing gate performance. Dielectric breakdown effects are particularly of concern in memory cells where gate leakage can result in the complete loss of stored data (Linder and Stathis, 2004). The critical Figure 1: A schematic representation of a MOSFET density of defects that is enough to trigger breakdown varies with dielectric material The operation of MOSFET devices is induced and thickness. In this research, we use by modulating the charge concentration in published uncensored dielectric failure data the MOS capacitor (the area defined by the in Wen (2004) to model dielectric failure gate electrode, the dielectric film and the using a three-stage hierarchical Bayesian substrate). For the negatively biased framework. MOSFET, when the applied gate voltage is positive and higher than the threshold 2 BAYESIAN INFERENCE voltage , an electric field is induced over Unlike classical statistical approaches such as the insulator which attracts negative charges the maximum likelihood estimation method (electrons) at the insulator/ substrate (MLE), and the least square error method interface. The electron concentration (LSE) that make inference from observations increases with an increase in the gate bias alone, Bayesian approaches provide an until the electrons form an inversion enrichment to statistical inference by conducting channel between the source and formalizing the process of learning from the drain. When the bias is reduced, the historical information to update parameter inversion layer is cut-off and the MOSFET estimates of a stochastic process (Robert, acquires the OFF status. 2007). This is made possible by the provision of the Bayesian hierarchical framework that When voltage is applied to a capacitor, the enables the use of acquired information. dielectric goes through several degradation Particularly, knowledge about the failure processes including charge carrier injection phenomenon, i.e. physics of failure is used to and a multistage dielectric breakdown as a sample the model hyper-parameters, and result of stress-induced defect generation provide physical meaning to the failure distribution parameters (Congdon, 2004).

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an indication of its fitness superiority over The Bayesian methodology starts with a the log-normal and the gamma distributions. prior distribution, of the unknown The same data was used to produce the random variable in the sample space . Let Weibull plots in Figure 2. be a random variable that has a probability These results agree with the suggestion by structure that depends on . Let Wu et al. (2005), that dielectric failure follows denote a random sample from the the Weibull distribution because: (i) failure distribution of and let denote a statistic occurs whenever a critical amount of defects which is a function of . Then the is reached, enough to form conductive paths conditional probability density function (pdf) that bridge the dielectric bulk, and (ii) the of for every , also known as the defects are uniformly distributed throughout likelihood function is given by . The the dielectric layer (Wu and Sune, 2005). The conditional pdf of given is the posterior likelihood function of the 2-parameter distribution and is given by: Weibull distribution is expressed as follows (Horst, 2008): (1)

2.1 Two-parameter Weibull Distribution (2) in the Context of Dielectric Breakdown

Goodness-of-fit tests using the MLE where is the scale parameter, is approach were performed in MATLAB using the shape parameter and real high-k dielectric failure data from Wen (2004) to determine the most appropriate , are the failure times. likelihood function. Table 1 contains a Henceforth, we will refer to the 2-parameter summary of the resulting p-values and the K- Weibull distribution as the Weibull S statistic corresponding to each of the distribution. distribution. These results show that the Weibull distribution has the higher p-value,

Table 1: Results of K-S goodness-of-fit tests for Weibull, log-normal and gamma distributions Electric field (in MV/cm) 8.1 7.9 7.7 7.5 7.3 7.1 Weibull fit Scale parameter 336.57 741.53 1301.70 2807.52 2451.66 3354.39 Shape Parameter 0.60 0.58 0.66 0.87 0.65 0.68 Log likelihood -222.28 -231.79 -281.75 -305.69 -303.43 -323.33 K-S test statistics 0.21 0.16 0.17 0.11 0.12 0.11 K-S test p-value 0.57 0.76 0.62 0.96 0.96 0.96 Lognormal fit Scale parameter 4.88 5.59 6.30 7.26 6.92 7.29 Shape Parameter 1.96 2.20 1.87 1.50 1.91 1.73 Log likelihood -222.96 -233.66 -283.42 -308.53 -305.23 -323.70 K-S test statistics 0.18 0.2 0.14 0.14 0.17 0.2 K-S test p-value 0.58 0.57 0.82 0.82 0.62 0.44 Gamma fit Scale parameter 977.29 2418.08 3115.64 3765.60 6195.65 7630.58

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Shape Parameter 0.49 0.45 0.54 0.79 0.53 0.57 Log likelihood -222.49 -231.54 -281.84 -305.61 -303.69 -323.77 K-S test statistics 0.22 0.2 0.20 0.14 0.20 0.18 K-S test p-value 0.35 0.53 0.42 0.82 0.42 0.59

Figure 2: Weibull plot of actual dielectric failure data from accelerated degradation tests

In Equation 2, the Weibull distribution is The scale parameter , also known as the characterized by the scale parameter, and characteristic life, is the time at which the shape parameter, . With reference to of the dielectrics will fail (Horst, 2008). In the dielectric failure process, the shape next section, we will discuss the physical parameter is assumed to be proportional to failure model using the Arrhenius the dielectric thickness, as expressed by degradation model proposed by Nelson (2006) and its implications on the Weibull (Sune at al., 2009): parameters. (3)

2.2 Arrhenius-Weibull Model where is the dielectric failure simulation The Arrhenius-Weibull model in 4 is a constant, equal to the defect diameter. The physical-statistical model that combines the proportionality constant , is assumed to be Weibull life description with the Arrhenius approximately 0.38 (Nigam et al., 2009). dependence of dielectric life on the stress Table 2, presents a summary of the conditions, which in our case is the amount of electric field applied to the dielectric maximum likelihood estimates of simulated failure times for a given dielectric thickness. (Nelson, 2006). The use of this model These results are in agreement with equation requires the following assumptions: (i) at any 3, and they show that increases with an stress level, the product life, indicated by the failure times has a Weibull distribution and increase in dielectric thickness. Physically, equivalently, the natural logarithm of the this is an indication that the dielectric failure failure times follows the extreme value rate increases with time. distribution, (ii) the Weibull shape parameter

Table 2: Shape parameter estimates of is constant at all stress levels, and (iii) the simulated failure time data natural logarithm of the dielectric’s characteristic life is a linear function of the Simulated 1 nm 2 nm 3 nm 4 nm 5 nm stress level (Nelson, 2006).

0.85 1.20 1.62 2.08 2.50

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In this equation, (measured in eV), test this difficulty, we propose the bounded temperature, T (measured in Kelvin, K), uniform prior, since there is limited Boltzmann constant, k (measured in eV per information regarding the underlying Kelvin, i.e., eV/K), applied electric field structure of the unknown parameters. In our (measured in MV/cm), and the field case, the only subjective information is acceleration parameter (measured in perhaps the range of values that the cm/MV) (McPherson, 2001). parameters can assume.

Similar to the work by Wen (2004), a (4) hierarchical Bayesian model is developed, which provides a way to incorporate If the first term in the exponent is replaced by subjective structural information about the a constant, (it is dimensionless and hence a unknown parameters in the likelihood constant) and assuming that the estimation function. In Equation 6, the Arrhenius- error is multiplicative, then we can linearize Weibull model is used to describe the Equation 4 as follows: relationship between the dielectric (5) characteristics life and the stress level, . where is the estimation error. It is safe to In the hierarchical Bayesian framework, conclude that the characteristic life, , will and are referred to as the hyper- have a similar relationship. parameters, and they are sampled from the (6) corresponding hyper-priors distributions ( , ) in the lowest stage of the Equation 6 will be useful later to develop the hierarchy (Figure 3). , the estimation error is hierarchical Bayesian model. assumed to be white noise. The priors of the unknown parameters and are estimated 2.3 Choice of Prior Distributions from these hyper-parameters in the In this research, the proposed Bayesian intermediate stage as shown in Figure 3. The model utilizes the two-parameter Weibull parameter estimates are then conditioned on likelihood function with noninformative the data to form the likelihood function in priors. When the Weibull parameters, and the highest stage of the hierarchy. are both assumed unknown, a prior should be placed on ( ). It is generally desirable that the joint prior should belong to a family of distributions that has a closed form, such that if the prior is conjugate, the resultant posterior will have a tractable form (Soland, 1996). A number of experts argue that it is extremely difficult to find a family of continuous joint prior distributions consisting of both parameters, that is closed under sampling (Canavos and Tsokos, 1973),

(De Sauza and Lamberson, 1999), in order to Figure 3: Graphical representation of the 3-stage ensure that the ensuing convolution results hierarchical Bayesian framework in a legitimate posterior distribution. Given

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In Equation 6, depends on , , and . (8) and are constants for different dielectric materials. The test temperature, should where denotes the stress level. ideally be constant. However, variation usually occurs as a result of environmental The following notations are used to describe conditions and calibration errors. In this the implementation of the hierarchical analysis, we examine two temperature Bayesian model. scenarios and the corresponding values, • namely: (i) constant temperature and at all : the stress level (electric field) in stress levels and, (ii) varying temperature MV/cm, for and from one stress level to the other. is • : the failure time at the the acceleration factor which determines the stress level for magnitude of the decrease in dielectric • : the vector of failure times, characteristic life , when the stress level is for the units at the stress level increased by one unit (Nelson, 2006). When • : the complete ( by ) matrix of is unknown, then it can be estimated by one all failure times for and of two methods: (i) the slope of the log-linear model in equation 5, or (ii) the ratio of • : the shape parameter of the dielectric characteristic life estimate at normal use conditions (using field data) and Weibull lifetime distribution, assumed the characteristic life at stress condition equal at all stress levels (using data from accelerated failure tests) • : the scale parameter of the (Nelson, 2006). We will estimate the Weibull lifetime distribution under stress acceleration factor based on two level conditions: when is constant at all stress • : model I acceleration regression levels, and when varies from one stress intercept level to the other. The estimation error is • : model I acceleration regression assumed to be multiplicative. slope • : model II acceleration regression Based on the foregoing discussion, we now intercept at the stress level construct two characteristic life models from • : model II acceleration regression equation 6 as follows (Wen, 2004): slope at the stress level • Model I: When the dielectric • : the acceleration model error characteristic life, , is different at term at the stress level every stress level, and the failure • The hierarchical Bayesian models I parameter and the acceleration factor and II are summarized as follows: are constant at all stress levels as

follows: Model I (7)

• Model II: When the characteristics life,

, is different at every stress level, and (9) both the failure parameter and the

acceleration factor differ at each

stress level as follows:

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In summary, our model uses the following Model II hyper-prior distributions.

(10)

2.4 Posterior Computation Given a vector of k unknown parameters

, the full or complete conditional 2.3.1 Limits of the parameters and hyper- parameters distribution for each parameter is described Hierarchical Bayesian models enable us to by: use a priori subjective information to set for limits to the bounded uniform priors as follows: For instance in our case, model I has the 1. The shape parameter is non-negative following unknown parameters: , , , and and it determines the nature of the failure . In our implementation, we use an iterative rate. We opt for uniform . mechanism that samples from the full 2. The estimation error , which is assumed conditional probability functions as was multiplicative is elicited a standard proposed by Wen (2004). normal distribution, thus: normal . 3. The model intercept . It is assumed (11) that for single-bonds of interest, the activation energy values range from eV to eV (for standard very-large- (12) scale-integration (VLSI) gate-oxide processing (McPherson, 2001), (Houssa et al., 2005). , the test temperature is (13) assumed to range between to (14) Kelvin, and , the Boltzmann constant is eV/K for application in where semiconductor physics calculations (Lui et al., 1992), (McPherson and Khamankar, and 2000). These specifications result in (15) values ranging between and (Lui

et al., 1992). For implementation where purposes, we extend the range of from

1 to 50, that is uniform . 4. The non-negative acceleration factor, 3 MCMC SIMULATION AND RESULTS varies from 0.1 to 10, that is The convolution between the prior and the uniform (McPherson, 2001). likelihood functions in order to obtain the posterior function cannot be determined in closed form due to its complexity. Therefore

104 Innovation Solution in Engineering (ISIE) A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 we used the Markov Chain Monte Carlo concave, slice sampling is employed when (MCMC) approach as a means to obtain the the support of the prior is bounded, while posterior estimates. The simulations were Metropolis algorithm is used when the implemented using the WinBUGS support is unbounded (Carlin and Louis, programming language. MCMC approaches 2008), (Chen et al., 2000). In our are used to solve multiple integrations that implementation, we let WinBUGS run with are required to obtain the marginal densities the default sampling procedure appropriate needed for Bayesian calculations. The for the prior distributions, which were: (i) objective of the MCMC methods is to create interval slice sampling for , and and (ii) an ergodic Markov chain whose limiting or adaptive Metropolis-Hastings sampler for . stationary distribution closely approximates the posterior distribution (Gelman et al., The credibility of MCMC posterior results 2004). Generally, MCMC methods are depends on model convergence. Basically, implemented using two fundamental model convergence ensures that the iterative sampling algorithms namely the Metropolis- simulations reach an equilibrium state of the Hastings (M-H) and Gibbs sampling Markov Chain. Therefore, when the Markov techniques (Gelfand, A.E, and Smith, F.M., chain induced by the MCMC algorithm fails 1990). More detailed discussions about to converge, the resulting posterior estimates MCMC sampling techniques as well as a rich will either be biased or unreliable (Chen et reference of related texts are provided in al., 2000). WinBUGS provides convergence Carlin and Louis (2008), Gelman, et al. (2004) diagnostics using trace plot, which are and Robert and Casella (2004). graphs of the updated posterior estimates at each iteration. In this work, convergence was When sampling, the Gibbs sampler in the determined by monitoring the trace plots, WinBUGS software, first attempts to and this enabled us to decide on the recognize if the parameter samples are to be simulation burn-in period. Based on the trial drawn from a conjugate prior. If conjugacy is simulations, we implemented fulfilled, the samples are drawn via direct iterations with burn-in iterations for sampling methodology using the prior model I and II. distribution. If the prior is not conjugate, WinBUGS does the sampling numerically The MCMC simulation results for models I through the rejection sampling technique and II are summarized in Tables 3 and 4 (Carlin and Louis, 2008). The most common respectively. In model I, we assume that the rejection sampling techniques are the Weibull shape parameter, and the Metropolis algorithm, adaptive rejection Arrhenius-Weibull model parameters, and sampling (ARS) algorithm and slice are constant across all stress levels. In sampling. The choice depends on the model II, we assume that , and different parameter descriptions. For instance, ARS is at each stress level. used when the parameter distribution is log-

Table 3: Posterior results:Bayesian hierarchical model I Node Mean St Dev MC Error 2.5% Median 97.5% 24.66 11.67 0.489 2.485 25.520 45.230 0.641 0.037 0.001 0.615 0.684 0.760 15.420 8.947 0.481 4.289 18.740 26.100 13.730 8.494 0.457 2.960 16.680 23.810 12.270 8.038 0.432 1.828 15.130 21.820 10.690 7.579 0.408 0.617 13.260 19.690

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9.572 7.132 0.383 -0.220 11.830 18.100 8.245 6.681 0.359 -1.233 10.370 16.230 2.452 2.399 0.129 1.595 2.571 7.187 5.903 0.266 0.003 5.394 5.898 6.438 6.737 0.278 0.004 6.204 6.731 7.297 7.202 0.257 0.004 6.71 7.197 7.721 7.837 0.262 0.004 7.346 7.83 8.374 7.837 0.260 0.004 7.332 7.835 8.358 8.134 0.260 0.004 7.643 8.128 8.662 379.4 104.9 1.492 220.2 364.5 625.2 877.0 254.5 3.828 494.6 837.8 1476.0 1388.0 368.9 5.981 820.5 1335.0 2256.0 2624.0 720.5 11.22 1550.0 2515.0 4334.0 2621.0 704.7 10.89 1529.0 2527.0 4262.0 3529.0 956.8 15.23 2086.0 3388.0 5780.0 Table 4: Posterior results:Bayesian hierarchical model II

Node mean st dev MC error 2.5% median 97.5% 24.76 14.13 0.589 1.654 18.88 47.87 22.56 12.03 0.500 1.923 20.69 43.2 23.6 13.98 0.583 1.995 22.02 48.61 25.59 12.56 0.523 4.969 30.18 49.34 22.45 11.9 0.495 6.354 32.21 49.29 25.08 12.81 0.534 2.539 27.48 48.38 0.641 0.086 0.098 0.464 0.651 0.803 0.620 0.087 0.001 0.434 0.590 0.779 0.656 0.090 0.001 0.507 0.673 0.865 0.882 0.119 0.002 0.660 0.878 1.13 0.643 0.088 0.002 0.501 0.659 0.844 0.632 0.090 0.002 0.524 0.69 0.878 3.918 8.139 0.341 -9.342 6.35 15.91 -0.656 5.321 0.223 -7.047 -2.35 11.21 9.569 16.73 0.702 -11.34 18.58 34.93 4.862 5.465 0.229 -3.346 3.136 15.11 -7.459 5.284 0.221 -16.79 -7.642 0.892 7.239 6.617 0.277 -1.456 5.394 24.47 2.499 2.149 0.089 0.353 2.057 6.085 2.021 1.56 0.064 0.566 2.972 6.039 2.941 2.52 0.105 0.599 2.096 7.397 2.665 1.684 0.070 1.798 2.808 7.583 2.999 1.635 0.068 0.700 2.024 7.816 2.629 1.741 0.072 1.992 2.667 8.728 5.903 0.271 0.001 5.387 5.898 6.448 6.734 0.278 0.001 6.205 6.728 7.299 7.196 0.259 0.001 6.703 7.190 7.721 7.845 0.259 0.001 7.353 7.839 8.372 7.841 0.261 0.001 7.345 7.837 8.369 8.128 0.256 0.001 7.639 8.122 8.648 379.9 106.9 0.481 218.6 364.3 631.6 874.2 254.1 1.056 495.2 835.1 1479.0 1380.0 370.6 1.568 815.1 1326.0 2255.0 2641.0 710.3 2.887 1561.0 2536.0 4323.0

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2633.0 713.8 2.993 1548.0 2533.0 4313.0 3504.0 930.5 3.931 2077.0 3369.0 5696.0

3.1 Comparison of Hierarchical Bayesian Model I and II 3.2 Sensitivity Analysis The Weibull shape parameter from model I Possible sources of uncertainty in Bayesian is 0.641 as seen in Table 3. Model II gave models include the choice of the likelihood several posterior mean values for which and prior functions, and the number of tiers are quite similar at a glance as seen in Table in the hierarchical model (Ioannis, 2009). 4. The value at the stress level is quite Therefore the most appropriate method to check for model robustness is to carry out removed from the rest, possibly due to an sensitivity analysis to determine whether the outlier in the failure data. The mean posterior posterior estimates remain unchanged after of from model II, which is the average slight perturbations in the prior and value of the estimates at 5 stress levels likelihood functions (Carlin and Louis, 2008). (excluding ) is 0.640. , the slope of the If the parameters remain the same, then the Weibull plot, is an indicator of a change in posterior is considered robust to a variety of the failure mechanisms, and hence failure data from the same problem domain. rate at varied stress levels. That is, a constant shape parameter across the stress levels In this research, posterior sensitivity was indicates that there is no change in the failure implemented by considering the different mode as the stress level is increased. Based combinations of the prior distribution as on the estimates of from the posterior shown in Table 5 for model I only. The base results of model I and II, we conclude that prior is the initial combination of prior there was no significant change in the failure distributions that was used to produce the mechanism of the dielectric at higher stress results in Tables 3 and 4. The result of the levels. Also, results from model I and II show base prior is then compared to results from that the dielectric failure parameters and five other prior distribution combinations in are consistent across the stress levels. Table 9 in the Appendix Section. The Following these results we concluded that , notation is such that denotes the posterior and are constant across stress levels, and estimate of using prior combination , and analyzed the sensitivity of the Bayesian denotes the posterior estimate of hierarchical approach using model I only in at stress level [1] using prior combination [1]. the next section.

Table 5: Table of priors for sensitivity analysis

Priors Base (1) Uniform (1,50) Uniform (0.1,10) Uniform (0,4) Normal (0,0.000001) 2 Uniform (1,100) Uniform (0.1,10) Uniform (0,4) Normal (0,0.000001) 3 Normal (50,1/100) Normal (5,1/10) Uniform (0,4) Normal (0,0.000001) 4 Normal (50,1/100) Uniform (0.1,10) Uniform (0,4) Normal (0,0.000001) 5 Uniform (1,50) Normal (5,1/10) Uniform (0,4) Normal (0,0.000001) 6 Uniform (10,40) Uniform (1,5) Uniform (0,4) Normal (0,0.000001)

The idea behind this sensitivity analysis is to consistency of the posterior estimates of the determine the robustness of our hierarchical Weibull shape parameter , the dielectric Bayesian model, by demonstrating the

Innovation Solution in Engineering (ISIE) 107 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 characteristic life , and the failure The objective of this paper is to make parameters and . Based on the results in reliability inference at the accelerated test Table 9, all the posterior estimates maintain levels followed by reliability projections at consistent values at all prior combinations. operating conditions. To do so, the estimates and estimates for prior combinations and of the dielectric characteristics life, and the exhibit relatively higher standard Weibull shape parameter from the hierarchical Bayesian approach in model I deviations than those obtained with prior using prior combination of Table 5 are combinations , , and . This indicates that compared to the corresponding estimates one should be careful in defining the limits of obtained using classical maximum likelihood assigned uniform priors. Otherwise the low procedure and the least square estimation. MC errors for and estimates indicate The Maximum Likelihood Estimates of the that the Bayesian model is robust to the shape parameters, , and the dielectric assigned prior distributions. characteristic life, at each stress level

4 RELIABILITY INFERENCE: MEAN were determined using MATLAB, resulting TIME TO FAILURE (MTTF) in a vector of and at each stress INTERPOLATION level as shown in Tables 6 and 7.

Table 6: Dielectric characteristics life estimates (seconds) Stress Methodology Mean Estimate 2.5% limit 97.5% limit 8.1 Hierarchical Bayes 3.07E+02 2.94E+02 8.44E+02 MLE 4.66E+02 1.56E+02 5.59E+02 LSE 5.05E+02 4.43E+02 5.51E+02 7.9 Hierarchical Bayes 4.80E+02 4.54E+02 1.29E+03 MLE 7.32E+02 2.52E+02 8.75E+02 LSE 7.92E+02 6.96E+02 8.62E+02 7.7 Hierarchical Bayes 7.49E+02 7.02E+02 1.98E+03 MLE 1.15E+03 4.05E+02 1.37E+03 LSE 1.24E+03 1.09E+03 1.35E+03 7.5 Hierarchical Bayes 1.17E+03 1.09E+03 3.04E+03 MLE 1.81E+03 6.52E+02 2.14E+03 LSE 1.95E+03 1.72E+03 2.11E+03 7.3 Hierarchical Bayes 1.83E+03 1.68E+03 4.66E+03 MLE 2.84E+03 1.05E+03 3.35E+03 LSE 3.06E+03 2.70E+03 3.30E+03 7.1 Hierarchical Bayes 2.86E+03 2.60E+03 7.15E+03 MLE 4.46E+03 1.69E+03 5.25E+03 LSE 4.79E+03 4.25E+03 5.17E+03

Table 7: Weibull shape parameter estimates

Stress Methodology Mean Estimate 2.5% limit 97.5% limit 8.1 Hierarchical Bayes 0.624 0.464 0.803 MLE 0.599 0.553 0.645 LSE 0.599 0.553 0.645 7.9 Hierarchical Bayes 0.594 0.435 0.779 MLE 0.583 0.437 0.778 LSE 0.537 0.504 0.570

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7.7 Hierarchical Bayes 0.676 0.507 0.865 MLE 0.667 0.511 0.871 LSE 0.633 0.596 0.671 7.5 Hierarchical Bayes 0.882 0.661 1.130 MLE 0.871 0.666 1.139 LSE 0.790 0.744 0.836 7.3 Hierarchical Bayes 0.663 0.501 0.845 MLE 0.655 0.503 0.853 LSE 0.625 0.597 0.653 7.1 Hierarchical Bayes 0.693 0.524 0.878 MLE 0.683 0.527 0.884 LSE 0.686 0.645 0.727

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One of the measures of reliability is the Mean summarized in Table 8, which also shows the Time To Failure (MTTF), defined as the Bayes, MLE and LSE extrapolated MTTF at 6 expected time to failure for non-repairable and 2 MV/cm. The confidence bands of system, or the expected time between two these estimates are also shown graphically in consecutive failures for repairable systems Figure 4. (Lewis, 1996). Generally, given a vector of failure times, , the MTTF Table 8: Comparison of MTTF estimates estimate is given by: Stress level MTTF (in seconds) (MV/cm) Bayes MLE LSE 2.0 3.39E+08 6.28E+08 6.67E+08 (16) 7.1 3.91E+03 6.20E+03 6.91E+03 7.3 2.50E+03 3.95E+03 4.42E+03 7.5 1.60E+03 2.52E+03 2.82E+03 For the Weibull distribution, the MTTF 7.7 1.02E+03 1.60E+03 1.79E+03 estimate is 7.9 6.56E+02 1.02E+03 1.14E+03 8.1 4.19E+02 6.48E+02 7.29E+02 (17)

In this section, a comparison is made between the MTTF values resulting from the Bayesian model, the MLE and LSE estimation methods. Since the main objective is to extrapolate the MTTF from test conditions to normal use conditions, we use Equations 18 to 20 to compute the characteristic life estimates at stress levels that represent normal use conditions, approximately Figure 4: Graph of Extrapolated MTTF ranging from 2 MV/cm to 6 MV/cm

(McPherson and Khamankar, 2000). Though results using model II and prior (18) combination 1 are not included in this section due to paper length consideration, the results(19) show that for stress levels (electric field)(20) ranging from 8.1 to 7.1 MV/cm, the dielectric characteristic life ranges from 380 to 3530 The Weibull shape parameter for Bayes, seconds respectively for both models. The MLE and LSE are averaged over all the average value for the Weibull shape estimates at , , , , and MV/cm parameter for model I is 0.641, while it is stress levels. The value of at MV/cm 0.638 for model II. The material related stress level is remarkably high, perhaps due failure parameter is 24.66 for model I and to an outlier in the failure data, and hence it the average value for model II is 24.00. The is excluded from the averaging procedure. acceleration factor is 2.452 cm/MV for The corresponding mean of estimates are model I while the average value for model II , , and . is 2.375 cm/MV. These Weibull parameter estimates are then used to calculate the MTTF values at the 5 CONCLUSION accelerated conditions. The results are

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We presented an integrated hierarchical To perform reliability inference at normal use Bayesian model for dielectric reliability conditions using the accelerated data, we estimation that incorporates dielectric failure constructed a log-linear extrapolation model. physics. Using the Arrhenius-Weibull This was done to determine the dielectric relationship, we develop a three-stage characteristic life , and hence the Mean hierarchical Bayesian model from the Time to Failure (MTTF) at normal use bounded uniform prior and the two- condition. Based on the MTTF analysis, the parameter Weibull likelihood function to Bayesian approach resulted in the smallest estimate and to establish a relationship mean time to failure in comparison to the among the dielectric characteristic life , the MLE and LSE approaches. However, the Weibull shape parameter , the accelerated MLE and LSE produced narrower stress level , the acceleration factor and confidence intervals. Typically, the MLE and the dielectric material and temperature LSE estimation techniques have better related parameter . We presented two asymptotic properties and therefore perform models: Model I: when only the dielectric better when the available data is large. When characteristic life is allowed to vary from one there is insufficient data such as in our case, stress level to another and Model II: when all the Bayesian estimation approach performs parameters are allowed to vary from one better as is evidenced in our results. stress level to another. Moreover, by using the Bayesian method, we are able to incorporate subjective dielectric Based on the simulation results we can failure information to model the conclude that the material and temperature characteristic life parameter, which is not related constant , and the acceleration factor possible with the MLE and LSE techniques. remained constant across the stress levels. For instance, we used the existing dielectric physics of failure expert information to This seems to indicate that model I offers a determine the limits of the uniform reference reasonable representation of the dielectric priors for the parameters and hyper- failure process. Also, the Weibull shape parameters. The parameters include the parameter , for a fixed dielectric thickness dielectric characteristic life, the failure rate remained constant across the stress levels. and the acceleration factor, all of which are Physically this means that an increase in the necessary to predict the life of a dielectric stress levels does not induce a different thin film. failure mechanism. However, the dielectric characteristic life, consistently increased Limited work has been accomplished in with increasing stress levels for both model I modeling the growth, performance and life and II, an indication that failure occurs faster of nanomaterials. We therefore perceive that at accelerated stress levels. Specifically, the the proposed work is not conclusive but confidence interval of the characteristic instead as a preliminary attempt to life of a 2 nm thick high-k dielectric at incorporate newly developed nanomaterial accelerated stress levels, at about 8.1 MV/cm growth and failure models into statistical is from 294 to 844 seconds while the models to make performance and reliability corresponding confidence interval at normal inference. use condition at about 2 MV/cm is from to seconds. 6 ACKNOWLEDGMENT This research was partially funded by NSF through the NSF GK-12 Fellows Grants

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(DGE-0139348 DGE-0638709) ”University scaling. Semiconductor Science of South Florida’s Student, Teachers And Technology 15, 436-444. Resources in the Sciences (USF Project Gelman, A., Carlin, J., Stern, H., Rubin, B., STARS).” The authors also gratefully 2004. Bayesian Data Analysis, 2nd acknowledge the anonymous reviewers for Edition. Chapman & Hall/CRC, Boca their valuable comments and suggestions. Raton, FL.

REFERENCES Hicks, J., Bergstrom, D., Hattendorf, M., Gelfand, A.E., Smith, F.M., 1990. Sampling- Jopling, J., Maiz, J., Pae, S., Prasad, C., based approaches to calculating 2008, 45nm transistor reliability. Intel marginal densities. Journal of Technology Journal 12, 1-16. American Statistical Association 85, Horst, R., 2008. The Weibull Distribution: A 398-408. Handbook. Chapman and Hall: CRC, Alam, M., Weir, B., Bude, J., S. P., Ghetti, A., Boca Raton, FL. 2001. A computational model for Houssa, M., Pourtois, G., Heyns, M., oxide breakdown: theory and Stesmans, A., 2005. Defect generation experiments. Microelectronic in high-k gate dielectric stacks under Engineering 59, 137-147. electrical stress: The impact of Canavos, G., Tsokos, C., 1973. Bayesian hydrogen. Journal of Physics: estimation of life parameters in the Condensed Matter 17, 2075-2088. Weibull distribution. Operations Ioannis, N., 2009. Bayesian Modeling Using Research 21, 755-763. WinBUGS. Wiley, John and Sons, Carlin, P., Louis, A., 2008. Bayesian Methods New Jersey. for Data Analysis, 3rd Edition. CRC Lewis, E., 1996. Introduction to Reliability Press, New York. Engineering, 2nd Edition. Wiley, John Chen, M., Shao, Q., Ibrahim, J., 2000. Monte and Sons, New York. Carlo Methods in Bayesian Linder, B., Stathis, J. H., 2004. Statistics of Computation. Springer, New York. progressive breakdown in ultra-thin Congdon, P., 2004. Bayesian Statistical oxides. Microelectronic Engineering Modeling, 2nd Edition. Wiley, John 72, 24-28. and Sons, Ottawa. Lui, H., Nee, P., Ko, K., Gross, B., Ma, T., De Sauza, I., Lamberson, L., 1999. Bayesian Cheng, C. Y., 1992. Field and weibull estimates. IIE Transactions 27, temperature acceleration of time 311-320. dependent dielectric breakdown for Degraeve, R., Govoreanu, B., Kaczer, B., Van reoxidized nitrided and fluorinated Houdt, J., Groesenken, G., May 2005. oxides. IEEE Electron Device Letters Measurement and statistical analysis 13, 41-43. of single-trap current-voltage McPherson, J., Khamankar, R., 2000. characteristics in ultrathin SiON. In: Molecular model for intrinsic time- Proceedings of the International dependent dielectric breakdown in Reliability Physics Symposium. pp. sio2 dielectrics and the reliability 360-365. implications for hyper-thin gate Degraeve, R., Kaczer, B., Groeseneken, G., oxides. Semiconductor Science 2000. Reliability: a possible Technology 15, 462-470. showstopper for oxide thickness McPherson, J. W., 2001. Physics and chemistry of intrinsic time-dependent

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dielectric breakdown in sio2 and shape parameters. IEEE dielectrics. International Journal of Transactions on Reliability 18, 181- High Speed Electronics and Systems 184. 11, 751-787. Sune, J., Tous, S., Wu, E., 2009. Analytical Moore, G. E., 1975. Cramming more cell-based model for the breakdown components onto integrated circuits. statistics of multilayer insulator IIE Transactions 38, 1-4. stacks. IEEE Electron Device Letters Nelson, W., 2006. Accelerated Testing: 30, 1359-1361. Statistical Models, Test Plans and Waldrop, M., 2016. The chips are down for Data Analysis, 2nd Edition. Wiley, Moore's law. Nature Publishing John and Sons, New Jersey. Group. Nigam, T., Kerber, A., Peumans, P., April Wen, L., 2004. Reliability characterization 2009. Accurate model for time- and prediction of high-k dielectric dependent dielectric breakdown of thin films. Ph.D. thesis, Texas A& M high-k metal gate stacks. In: University. Proceedings of the International Wu, E. Y., Sune, J., 2005. Power-law voltage Reliability Physics Symposium. acceleration: a key element for ultra- Montreal, Canada, pp. 523-530. thin gate oxide reliability. Robert, C., 2007. The Bayesian Choice: From Microelectronic Reliability 45, 1809- decision-theoretic foundations to 1834. computational implementation, 2nd Wu, Y., Sune, J., Vollertsen, R., 2009. Edition. Springer, New York. Comprehensive physics-based Robert, C., Casella, G., 2004. Monte Carlo breakdown model for reliability Statistical Methods, 2nd Edition. assessment of oxides with thickness Springer, New York. ranging from 1 nm to 12 nm. IEEE 47th Soland, R., 1969. Bayesian analysis of the Annual International Reliability Weibull process with unknown scale Physics Symposium 47, 708-717.

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Appendix

Table 9: Sensitivity Analysis Node Mean St Dev MC Error 2.5% Median 97.5% Prior 24.66 11.67 4.90E-01 2.49 25.52 45.23 uniform (1,50) 24.53 11.12 5.97E-01 10.45 27.31 44.88 normal (50,1/100) 23.97 0.27 1.27E-02 22.44 23.99 24.45 normal (50,1/100) 22.79 1.22 6.09E-02 19.78 22.78 24.57 normal (50,1/100) 24.53 4.10 2.05E-01 11.87 14.76 26.09 uniform (1,50) 22.54 8.56 4.06E-01 10.23 20.04 36.70 uniform (10,40) 0.68 0.04 6.15E-04 0.61 0.68 0.76 uniform(0,4) 0.69 0.04 1.01E-03 0.61 0.68 0.76 uniform(0,4) 0.68 0.04 1.55E-03 0.61 0.68 0.76 uniform(0,4) 0.68 0.04 9.47E-04 0.61 0.68 0.76 uniform(0,4) 0.69 0.04 8.64E-04 0.61 0.68 0.76 uniform(0,4) 0.69 0.04 7.91E-04 0.61 0.68 0.76 uniform(0,4) 2.32 1.60 6.71E-02 1.27 3.92 7.09 uniform(0.1,10) 2.46 2.40 1.29E-01 2.60 6.57 9.19 uniform(0.1,10) 2.24 0.25 1.24E-02 1.37 3.00 3.20 normal(5,1/10) 2.93 0.85 4.27E-02 2.48 4.98 6.00 uniform(0.1,10) 2.37 0.28 9.11E-03 3.05 3.33 3.73 normal(5,1/10) 2.60 0.95 4.49E-02 2.11 3.60 4.96 uniform(1,5) 5.90 0.27 3.87E-03 5.39 5.90 6.438 5.90 0.27 3.98E-03 5.38 5.90 6.439 5.91 0.27 5.01E-03 5.40 5.91 6.448 5.90 0.27 5.42E-03 5.37 5.89 6.44 5.90 0.27 4.11E-03 5.39 5.89 6.44 5.91 0.27 4.72E-03 5.39 5.90 6.45 6.74 0.28 4.18E-03 6.20 6.73 7.30 6.74 0.28 4.32E-03 6.21 6.73 7.31 6.75 0.27 5.00E-03 6.23 6.74 7.30 6.74 0.28 5.17E-03 6.20 6.73 7.30 6.74 0.28 4.46E-03 6.21 6.73 7.29 6.73 0.28 4.96E-03 6.20 6.72 7.29 7.20 0.26 4.13E-03 6.71 7.20 7.72 7.19 0.26 4.28E-03 6.69 7.19 7.72 7.20 0.26 4.94E-03 6.71 7.20 7.74 7.20 0.25 4.87E-03 6.73 7.19 7.71 7.20 0.26 3.99E-03 6.70 7.19 7.721 7.20 0.26 4.71E-03 6.71 7.19 7.71 7.84 0.26 4.12E-03 7.35 7.83 8.37 7.85 0.26 4.24E-03 7.36 7.84 8.39 7.85 0.26 4.49E-03 7.36 7.84 8.37 7.85 0.26 5.28E-03 7.37 7.84 8.38 7.85 0.26 3.91E-03 7.36 7.84 8.37 7.84 0.26 4.86E-03 7.35 7.83 8.374 7.84 0.26 4.10E-03 7.33 7.84 8.36 7.84 0.26 4.11E-03 7.34 7.83 8.36 7.85 0.26 4.58E-03 7.36 7.85 8.38

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7.84 0.26 5.03E-03 7.33 7.84 8.35 7.84 0.26 4.00E-03 7.33 7.83 8.36 7.84 0.26 4.80E-03 7.35 7.84 8.37 8.13 0.26 4.18E-03 7.64 8.13 8.662 8.13 0.26 4.27E-03 7.64 8.12 8.64 8.13 0.25 4.36E-03 7.65 8.13 8.64 8.13 0.26 5.27E-03 7.63 8.12 8.65 8.12 0.26 4.23E-03 7.64 8.11 8.65 8.13 0.26 4.65E-03 7.64 8.12 8.65

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INNOVATIONS IN HHO GASES PRODUCED THROUGH WATER ELECTROLYSIS

E. C. Ugwuagbo Department of Electrical & Electronics Engineering, University of Lagos [email protected]

ABSTRACT This paper presents recent developments in on-demand hydrogen-Oxygen (HHO) gas produced through water electrolysis, to identify the routes, which will lead to a gradual adoption of on-demand HHO gas application as a fuel source or supplement. Different applications of HHO gas such as fossil fuel combustion enhancement and environmental pollution control, welding, cutting, heating and cooking stove deployments are discussed. It is shown that HHO fuel is fast emerging as green energy technology to tackle the environmental pollution problems associated with conventional fuel technologies. However, current HHO technology is not yet competitive but highly promising. This research seeks to provide an innovative way of producing brown gas with less energy consumption and better efficiency using Pulse Width Modulation (PWM) control.

Keywords: Brown Gas, Hydrogen, Water Electrolysis, Fuel Combustion Enhancement.

1. INTRODUCTION fuel to replace/supplement conventional he world’s fossil fuel reserve is fossil fuels. decreasing daily, coupled with T increase in greenhouse gases in the Hydrogen produces only water during atmosphere due to its consumption. The combustion, it is carbon free, non-polluting incomplete combustion of Fossil fuel also and renewable form of energy. The causes unfavourable exhaust gas emission, combustion characteristics of hydrogen such which is one of the major sources of as high diffusivity, wide flammability limits, environmental pollution worldwide. This has low ignition and high flame energy speed directed research efforts to device means to makes hydrogen blended fuels to burn more optimise fossil fuel consumption, improve effectively (Yilmaz et al 2010). This paper engine efficiency, and reduce environmental reviews different applications of pollution. The development of hydroxyl fuel also called Hydrogen-Oxygen fuel or Brown HHO gases as a fuel source and provides an Gas is one such effort. This type of fuel is innovative way of producing more efficient obtained by water electrolysis. Electrolysis HHO gases using less energy, which is of water is a process in which water is split undergoing development in Nigeria. into hydrogen and oxygen by passing electric current through water to break the bond of 2. RECENT RESEARCH RESULTS. water molecule. This method produces One of the major uses of HHO gas mixture is hydrogen and oxygen gases in the ratio of 2:1 to enhance the combustion of hydrocarbon (HHO). Hydrogen fuel is a clean and suitable fuels used in internal combustion engines, such as gasoline, diesel, petrol or natural gas.

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This type of combustion is called dual-fuel internal combustion engines and can combustion. Hydrogen enriched combustion improve the emissions and performance of can be either used in small quantity to an SI engine. COVn and COVimep, indicated enhance complete combustion of thermal efficiency, ISFC, CO and THC values hydrocarbon or as the principal element in were improved with hydrogen addition, only the combustion chamber. Several researchers NOx emissions increase. Therefore, have investigated these types of operation of Hydrogen is applicable as fuel supplement in hydrogen-assisted combustions. both SI and CI engines to enhance engine performance. However, further research Shahad & Hadi (2011) blended hydrocarbon need to be done to increase the efficiency. fuels with hydrogen gas to study the reduction in the concentration of pollutants 3. HHO R & D EFFORTS IN NIGERIA coming out from a diesel powered internal The HHO team in Nigeria consists of an combustion engine. Their results showed inter-disciplinary group drawing experts in that 10% by mass of HHO diesel fuel mixture Electrical, Electronics and Chemical led to maximum reduction in specific fuel Engineering in collaborating with local and consumption (sfc) by about 35%. Same ratio international Small Scale Entrepreneurs. The also gives maximum improvement in Brake author is part of this team. Figure 1. depicts Mean Effective Pressure (bmep) of about 25% the basic circuit used for HHO generator while maximum improvement in engine control, for such functions as; current flow, efficiency increases by 40%. automatic water pump, pressure control, cooling system, and system protection. With Ganesh and Dhumal (2017) investigated the this circuit in place, the HHO generator performance of hydrogen enriched diesel system generates brown gas. Current engine. Their results showed that on-board Injection control is achieved through a Pulse generation of hydrogen by electrolysis Width Modulated (PWM) circuit, which overcomes volumetric efficiency issue which controls the current allowed into the cells; is lowered due to increase in heat release rate this reduces the amount of energy used in as hydrogen enrichment is increased. This the production of HHO gas by reducing the also overcomes the storage of highly energy lost as heat, thereby increasing the inflammable hydrogen. It is also observed generator efficiency. Figure 2 shows HHO that the emissions of HC, CO2 and CO were generator under construction. This generator found to be lowered due to complete will produce 5 litre/minute of brown gas for combustion. However, NOx increased due to industrial diesel engine generators the higher combustion temperature. application. Other prototypes have been tested but the quantum of gas produced falls Yasin et al (2015) studied the effect of short of expectation. The current design different percentage concentration of holds better promise. hydrogen (0%, 5%, 8%, 10% and 15%) on coefficient of variation in the engine speed (COVn), the indicated mean effective pressure (COVimep), peak in-cylinder temperature, energy flow rate, indicated thermal efficiency, specific fuel consumption, THC, CO, and NOx. The study showed that hydrogen is an environment-friendly fuel for

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increase. However, the disadvantage involved in the use of HHO gas in cutting is the possible risk of minor explosion as a result of working with the gas mixture.

There are currently few researches done in the area of using HHO gas in domestic cooking application. A study has shown that the use of hydrogen gas in cooking stove will result to energy efficiency of 66% compared to conventional gas stoves, which is approximately 56 %, and electric stove which Figure 1: Electrical Circuit Diagram of HHO generator would be only approximately 35 % (Fumey et al 2014). Further research need to be carried out in this area to develop a safe, reliable and affordable system for on- demand cooking gas application.

3. CHALLENGES TO HHO FUEL There is enormous gap between our present capabilities for HHO production, storage, and use and those required for a competitive HHO fuel economy. To produce hydrogen, another energy source is required because hydrogen cannot easily be extracted from Figure 2: HHO generator under construction water. One of the major challenges to HHO production and application is that there is HHO gas can also be used for welding and currently no competitive and long-term metal cutting purposes and as cooking gas. means of efficient, economic and clean Large HHO Gas generators can be widely production HHO gas. To be efficient, the used in Carbon Steel Cutting and continuous production process should not use casting slab cutting of Steel Plant. It can be excessively more energy to create hydrogen incorporated in manual cutting torch, semi- fuel than is derived from burning hydrogen automatic cutting machine, shape cutting fuel. The efficiency of water electrolysis is at machine, CNC cutting machine instead of best only 75% (Slakey). The cost of electricity traditional fuel gas. HHO gas can also be primarily drives the current cost of used for heating, polishing and sealing production of HHO gas through water applications. Tusek et al studied the electrolysis. operation characteristics of water powered hydrogen gas steel cutting machine. The 4. CONCLUSION results from this study showed that the flame Generation of hydrogen in a form called of HHO gas does not deposit carbon hence Brown’s gas (HHO) by electrolysis is a very cleaning is easier, and also resist corrosion. revolutionary idea because water is a The study also found out that the use HHO renewable resource and readily available. gas in welding and cutting reduces the The high burning velocity, wide flammability process time while the health of instruments range, high diffusivity and low ignition

Innovation Solution in Engineering (ISIE) 117 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 energy are the main characteristics that make International Journal of Mechanical, hydrogen a potential additive for different Aerospace, Industrial, Mechatronic type of hydrocarbon fuels and stand-alone and Manufacturing Engineering application. Hydrogen fuel is fast emerging Vol:5, No:4, 2011 as green energy technology to tackle the Ganesh Kerkal, Krishna Pawale, and Amol problems on pollution associated with Dhumal. “Diesel Engine with conventional fuel technologies. However, Hydrogen in Dual Fuel Mode: A current technology is highly promising but Review”. International Journal for Research not competitive, more research work need to in Applied Science & Engineering be done to solve the fundamental science Technology (IJRASET), Volume 5 challenges associated with HHO gas Issue V, May 2017 production through electrolysis. Yasin Karagoz, Tarkan Sandalc, and Ahmet Given the multidisciplinary nature of the Selim Dalkılıc. “Effects of hydrogen scientific problems involved, diverse group and oxygen enrichment on of companies, universities, and national performance and emissions of an SI laboratories should work together to ensure a engine under idle operating reliable, safe, affordable and competitive condition”. International Journal of production, storage, transportation and Hydrogen Energy 40 (2015) 8607- application of HHO gas. 8619. BBN Partner Bioclean and BlueEnergy REFERENCES network. “Hydro-Oxygen Water Gas: Ali Can Yilmaz, Erinc¸ Uludamar, and Kadir Brown Gas for Combustion and Metal Aydin. “Effect of hydroxy (HHO) gas Cutting”. addition on performance and exhaust J. Tusek and M. Sraj. “Oxy-Hydrogen Flame emissions in compression ignition For Cutting Of Steels”. engines”. International Journal of METALURGIJA 46 (2007) 3, 211-215. Hydrogen Energy 35 (2010) 1136- Benjamin Fumey and Ulrich F. Vogt. 1372. “Hydrogen fueled stove for autarkic Haroun A.K. Shahad, Nabeel Abdul-Hadi. living”. Status-Seminar. Forschen für “Experimental Investigation of the den Bau im Kontext von Energie und Effect of Hydrogen Manifold Umwelt. September 2014. Injection on the Performance of Francis Slakey. “The Hydrogen Initiative”. Compression Ignition Engines”. Associate Director of Public Affairs, World Academy of Science, American Physical Society (202) 662- Engineering and Technology. 8700, March 2004.

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GUIDELINES FOR AUTHORS

AIM AND SCOPE The aim of the Journal is to provide a medium for exchange of ideas and knowledge at the highest level of the engineering profession in Nigeria towards providing innovative solutions to infrastructural and engineering problems confronting Nigeria in particular, Africa and the world in general. The journal covers all areas of Engineering applications and focuses on problems rather than disciplinary boundaries. Areas of focus include but not limited to: conventional energy and power; renewable energy and clean energy solutions; transport; housing and shelter; smart cities; water resources; environment and waste management; agriculture and food; oil and gas; operations research; materials; information and communications; healthcare, manufacturing, mining and solid minerals development; engineering economics and management.

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The manuscript should generally be arranged as follows:  TITLE  KEYWORDS  ABSTRACT  INTRODUCTION  MAIN BODY  CONCLUSION  ACKNOWLEDGEMENTS  REFERENCES  NOMENCLATURE  APPENDIX

1. TITLE The title should identify the subject, indicate the purpose of the subject and contain relevant keywords. It should supply enough information for the reader to make a reliable decision on probable interest. A short informative title is preferred over a long one. Titles should normally not exceed 15 words. Use uppercase, bold for the title. The title should be followed by the author(s)’s full name written in lower case letters. Each name should be written as surname first, then comma before the first and middle names. Capitalize only the first letter of the first word in the name. The names should be followed by affiliations and email addresses of the

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2. KEYWORDS Provide at least five keywords relevant to the subject for purposes of indexing.

3. ABSRACT The purpose of an abstract is to provide a clear and concise summary of the information presented in the article. The abstract should normally contain a sentence on the background to the work, a sentence on the statement of the problem, rationale, hypothesis of the work, a brief description of the methods, a summary of the results and conclusion. Literature citations and references to tables, figures, or equations found in the body of the manuscript should not be used. The abstract should contain only enough about methodology to provide a context for the results, which are presented next. A summary of the results should include the major trends. The goal of the abstract is to state only the most important results of the study. Data may be given to emphasize the results, including statistical results. The abstract should end with a brief statement of the conclusions and implications of the study. For a critical review paper, the style is slightly different. The abstract will contain the background, statement of the problem, approach used, different areas analyzed, major findings, policy implications and recommendations for way forward.

4. INTRODUCTION The introduction should start with a brief background to the problem including a description of earlier work done, the state of research or work in the subject area, the gap in knowledge and the need for the present study. It should then define the problem and give a concise justification and rationale for the study. The Introduction should end with the main aim and objectives of the work stated in clear terms.

5. MAIN BODY The main body will vary depending on the nature of the work presented. For an experimental work, this section should contain the description of the location or materials, experimental procedures, design of experiments, development and validation of theoretical models, statistical analysis of data. These can be organized in chronological, spatial, geographical, or any other sequence that develops logically. For such experimental, design or theoretical work, the main body will have two major headings. The first is “Materials and Methods”. Information about materials and methods should be provided in sufficient detail so that the work may be repeated. You should reference all methods previously used and specify whether the methods had been modified and, if so, how. The second major heading is “Results and Discussion”, which can have sub sections where different aspects of the results are presented and discussed. The author should present the results using tables and figures as relevant and discuss them as they occur. Such discussion will include conformity or otherwise with existing knowledge, major breakthrough and implications. The results should address the objectives.

For a critical review paper, there is no need for separate sections on “Materials and Methods”. Rather, the main body should be subdivided to several sections according to the relevant areas

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6. CONCLUSIONS This section re-states the major findings and recommendations of the study and should be brief and concise. No new issues should be presented here. It can start with a brief summary of the work and then end with the major conclusions. Note that a reader that does not have time will read only the abstract and the conclusion.

7. ACKNOWLEDGMENTS This section is used for acknowledging any funding agencies that gave grants or support for the work. It is not a place for thanking family members.

8. REFERENCES The “name-date” method of reference is used. References should help the reader, librarian, or indexer to retrieve the items cited and therefore should be done in an orderly manner in such a way that they are verifiable. Within the text, refer to the item with the name of the author and year of publication. Example – Okonkwo (2017), for single author; Abubakar and Ahmed (2017), for two authors and Afolayan et al (2017) for more than two authors. These should be listed in full in the section on references in alphabetical order of the surname of the first author.

Examples: Reynolds, D.P. 2017. Introduction to Fluid Mechanics. Macmillan Publishers, Lagos. pg213-300. Ochigu, T.B. 2016. Effect of velocity on drag coefficient. PhD Thesis, African University of Science and Technology, Abuja. Abubakar, Y.M; Offor, B.N. and Ojo, W.P. 2017. How to Write a Journal Paper. International Journal of Writing. Elsevier. 233(3):45-89.

9. NOMENCLATURE Assemble and define all mathematical symbols, abbreviations, etc in this section.

10. APPENDIX Provide an appendix if necessary. This is used where there is need for further explanation of an issue. This is only allowed in special cases where a reference cannot be provided for the reader.

11. MATHEMATICAL EQUATIONS Mathematical equations should be progressively numbered as they occur. All symbols used must be defined at their point of first occurrence and listed and defined under Nomenclature.

12. FIGURES, GRAPHS, CHARTS, PICTURES Figures are important in presentations. You should include figures to emphasize points made in the text, not merely to illustrate tabular material graphically. Illustrations attract the reader's attention, clarify the text, and should not be included unless discussed in the text. Graphs and charts should be designed to improve the general presentation of a technical publication by reporting data in a manner easy to comprehend. The decision to select and use charts or graphs

Innovation Solution in Engineering (ISIE) 121 A Journal of the Nigerian Academy of Engineering Vol. 1, No. 1, June 2018 should be governed by the writer's message and the points to be brought out in the illustration. Graphs primarily show trends; therefore, it is not necessary for you to show all the coordinate rulings in most graphs. Photographs should only be used if they show something essential to the point being made. High quality photos made for slide projections or talks are usable if they make a point. All graphs, charts, photographs are referred to as Figures and should be numbered as Figure 1, 2, 3…. In order as they occur. All figures taken from previous publications should be properly referenced. The figure caption should be placed below the figure. Colour can be used where necessary.

13. TABLES Tables are used for reporting extensive numerical data in an organized manner. They show classifications, facilities comparisons, reveal relationships, and save space. They should be self- explanatory. Data presented in tables should neither be duplicated in figures nor reviewed extensively in the text. Give specific references and explanation in the text to introduce each table. It is seldom necessary to use a table for fewer than eight items of data. Table captions should be brief, but must sufficiently explain the data included. Number your tables consecutively and refer to them in the text as table 1, table 2, etc. Show the units for all measurements in spanner heads, in column heads, or in the field. Use no more digits than the accuracy of the method justifies. Table captions should be on top of the Table.

14. SUBMISSION OF MANUSCRIPT Manuscripts should be submitted electronically as attached file in MS Word. This should be submitted to any member of the Editorial Board (see emails listed).

122 Innovation Solution in Engineering (ISIE)