Hura Crepitans

Measurement of some engineering properties of sandbox seeds ( Hura crepitans ) * Idowu, D O; Abegunrin, T.P; Ola, F A; Adediran, A.A; Olaniran, J A Department of Agricultural Engineering, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria. ABSRACT The physical properties of kernels, grains and seeds are necessary for the design of equipment to handle, transport, process and store the crops. The physical properties of Hura crepitans seed have been evaluated as a function of moisture contents from 9.3 to 52.4% (wb). In the moisture range considered, seed length, width, thickness, one thousand weight and geometric mean diameter increased linearly from 20.4 to 22.8mm,21.1 to 23.0mm, 5.0 to 6.9mm ,860 to 1600g and 12.89 to 15.39mm respectively. The volume, sphericity, and surface area also increased from 758.38 to 1098.91mm3, 0.63 to 0.69 and 522.55 to 744.09mm2 respectively, whiles the bulk density and the true density are 0.55 and 13.40g/mm3 respectively. It was observed that material surface is the most determinant of the magnitude of the coefficient of static friction. The coefficient of friction was highest on plywood with 0.37 for seeds and 0.66 for kernel while the lowest coefficient of friction was recorded on stainless steel, 0.32 and 0.43 for seeds and kernels respectively. For all surfaces the kernels recorded the highest coefficient of friction. Also, the kernel angle of repose was 26.20 which are higher than angle of repose recorded for seeds, 19.20. The results of the experiment will contribute immensely to the existing knowledge aimed at solving the problems of equipments design to handle the processing of seeds. Keywords: Physical properties, moisture content, Density, Coefficient of friction, Angle of repose

INTRODUCTION The knowledge of various physical, mechanical and Sandbox tree (Hura crepitans ) is an evergreen tree chemical properties of agricultural products are very that belongs to the spurge family (Euphorbiaceae ) essential to the designs of suitable machines and equipment for the handling, processing and storage that grows in the tropical regions of the world of these products. Size and shape of the materials (Wikipedia encyclopedia, 2009). The tree can be recognized by the presence of many dark conical are useful in sizing, sorting and other separation spines that covers the bark and its large heart process. Bulk and true densities of the materials are important in order to design equipment for its shaped leaves with prominent secondary veins. The processing, sorting, grading, transporting and storing. fruits produced are pumpkin shaped seed pods which The angle of repose is important for designing are usually green when fresh and brown when dry. package or storage structures and the coefficient of The fruit is characterized by its tendency to break with an explosive sound when ripe and dry, splitting friction plays an essential role for transportation, the seedpods into segments catapulting the seeds as handling and storage structures. far as 100 m. In recent years, many researchers have investigated the physical properties of some seeds, these includes In most parts of the world, the trees have been used as shade because of its large spreading branches. In the sunflower seed (Gupta and Das, 1997); guna seed (Avaira et al., 1999); African breadfruit seed ( some places, the leaves are used for medicinal Omobuwajo et al., 1999); locust bean seed ( purposes (Striweb.com, 2009) but the seed has not Ogunjimi et al., 2002); okra seed (Calisir et al., 2005); been fully exploited as there is dearth of information nutmeg seed (Burubai et al., 2006); sponge gourd on the properties, traditional handling methods and seed (Ogunsina et al., 2009) and soya bean seed utilization of the seeds. However, it has been (Tavakoli et al., 2009). However, review of literatures reported that the seed contain oil and some essential shows that there is no information on the physical vitamins. The oil may be useful in industries for even and mechanical properties of Hura crepitans. food, feed, paints, and cosmetics. Therefore, the objective of this study was to

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investigate the moisture dependant physical method was chosen since there is no approved properties of the seed. method for determining the moisture content of this MATERIALS AND METHODS type of oilseed material. The moisture contents (Wet basis) of the seed and kernel samples were Bulk quantities of mature and dry sandbox tree (H. determined by the relationship: crepitans) fruits were collected from the premises of % Moisture =100 (W – W )/W (1) the University of Ibadan campus, Ibadan, Nigeria. I f i The seedpods were broken manually to get the Where: seeds (Plate 1A) and some of the seeds were shelled W i = initial weight of the seeds to obtain the kernels (Plate1B). W f = final moisture content of the seeds Average moisture content of H. crepitans seed collected was found to be 9.3% (w.b.). The samples of the desired moisture content level were prepared by adding calculated amounts of distilled water and sealing in separate polyethylene bags. The samples were kept at a temperature of 5 o C in a refrigerator for a week to enable the moisture distribute uniformly throughout the samples. The test were carried out after removing the required quantity of the H. crepitans seed out of the refrigerator and was allowed to warm up to room temperature. This method has been used by Sessiz et al. (2007) and Tavakoli et al. (2009). Size: The size was determined by measuring the linear dimensions; length, width, and thickness of 100 Plate 1 A: The Hura crepans seeds randomly selected Hura crepitans seeds and kernel, using a vernier caliper. The geometric mean diameter (Dg), shpericity (Ø) and surface area (S) were determined from the following relationships 1/3 Dg= (LWT) (2)

Ø= (3)

S= Dg (4) Where L is the length; W is the width and T is the thickness. These relationships have being used by Moshenin, (1986); Ogunsina et al. (2009); and Tavakoli et al. (2009). Plate 1 B: Kernel of Hura creptans One hundred seed mass: The thousand seed mass The physical properties were measured at five was determined using a digital electronic balance different seed moisture content (9.3, 22.2, 32.0, 42.3, Tubol 005 model having an accuracy of 0.001 g. To 52.4% w.b.) while that of the kernel was taken at evaluate the thousand seed mass, 1000 seeds were 8.6% (w.b.). randomly selected from the bulk sample and weighed. The experiments were replicated three Moisture content determination: The initial times. moisture content of the samples was determined by oven drying the samples at temperature of 105 oC for True volume, density and bulk density of the 6 h adopted from Olaoye (2000) and Ozguven et al. seed: According to Jain and Bal (1997) and Ozguven (2005) for castor nut and pine nuts respectively. This

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et al. (2005) the volume of the seed and kernel was replicates in each case. The angle of repose was given as follows: calculated using the equation bellow which was adapted from literature [Kaleemullah and Gunasekar V= (5) , (2002); Ozguven and Varsavusl (2005); Sessiz et al., (2007)]: Where = tan-1 (10) B = (WT) 0.5 (6) The true volume of the seed was determined using Where H is the height of the cone and D is the the water displacement method (Moshenin, (1986); diameter of the cone. Ogunsina et al., (2009)). The seed was weighed in air Coefficient of friction: The static coefficients of and allowed to float in water. The volume of water friction of the seeds and kernels against five different displaced was recorded. This was repeated for the surfaces namely: stainless steel, galvanized steel, kernel and there were 5 replicates in each case. True mild steel, aluminum and plywood were determined density ( t) of the seed and kernel were calculated as described by Ozguven et al. (2005) and Ogunsina using the relationship: et al. (2009). The inclined plane was gently raised and the angle of inclination at which the samples t= w (7) started sliding was read off the protractor. The tangent of the angle was reported as the coefficient Where w is the density of water; Ma and Mw are of friction (Dutta et al., 1988): mass of seed or kernel in air and water respectively. μ= tan (11) The bulk density was determined using the mass/volume relationship, by filling an empty plastic Where, μ is the coefficient of friction and is the tilt container of predetermined volume and weight with angle of the friction device. All the friction the seeds poured from a constant height, striking off experiments were conducted in five replications for the top level and weighing. This was also repeated each surface. for the kernels and the bulk density was calculated RESULTS AND DISCUSSION as: Physical properties: The results of the experiments b= (8) performed on the physical properties of Hura creptans and the effect of moisture content on them

Where b is the bulk density, M and V are bulk mass is as discussed below. of seed or kernel (g), and the plastic container Linear dimensions: Average values of the three volume respectively. Owolarafe et al. (2007); principal dimensions of Hura crepitans seeds i.e. Ogunsina et al. (2009); and Tavakoli et al. (2009) length, width and thickness determined in this study have used the same method for other crops before. at different moisture contents are presented in Table The porosity of the seeds and kernels were 1. It was observed that the moisture content affect calculated from the bulk and true densities using the the principal axis. From this, as the moisture content relationship given by Moshenin (1986) as follows: increased from 9.3% to 52.4% (w.b), the average length, width and thickness of the seeds varied from ε= (1 - × 100 (9) 20.4 to 22.8 mm, 21.1 to 23.0 mm and 5.0 to 6.9 mm respectively. The various results were plotted against

Where ε is the porosity, b is the bulk density, and t the moisture content (Fig.1). The following regression is the true density. equations were developed for the length, width and thickness of Hura crepitans seed with moisture Angle of repose: The angle of repose is the angle content: with the horizontal at which the material will stand 2 when piled. This was determined by using a L= 19.89 + 0.043Mc (R =0.922) (12) cylindrical container open at both ends. The cylinder W= 20.03 + 0.067Mc (R2=0.855) (13) was placed on a wooden table, filled with the seeds 2 T= 4.620 + 0.040Mc (R =0.955) (14) and raised slowly until it formed a cone of seeds. This was repeated for the kernels and there were five

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Geometric mean diameter: The average values of Çalişir et al. (2005) for Turkey okra seed, Sessiz et geometric mean diameter of Hura crepitans seeds al. (2007) for caper fruit and Tavakoli et al. (2009) for calculated at different moisture contents are given in soya bean seed. The regression equation for the Table 1. It is seen that the geometric mean diameter effect of moisture content on Geometric mean increased from 12.89 to 15.39 mm as the moisture diameter of Hura crepitans is as presented in content increased from 9.3 to 52.4% (w.b.) (Fig.2). equation 15. Similar increasing trend have been reported by 2 2 Dg= 0.000Mc + 0.015Mc + 12.73 (R = 0.991) (15) Table 1: Axial dimensions of Hura crepitans seed at different moisture contents

Properties

Moisture content (wb) 9.3 22.2 32.0 42.3 52.5

Length (mm) 20.42 20.80 21.30 21.40 22.40

Width (mm) 21.11 21.30 21.50 23.20 23.80

Thickness (mm) 5.02 5.60 5.90 6.10 6.90

Geometric Mean Dia. (mm) 12.89 13.50 13.89 14.43 15.39

Sphericity (decimal) 0.63 0.64 0.65 0.67 0.69

Volume (mm3) 758.38 876.56 969.10 1098.91 1345.13

Surface area (mm2) 522.55 572.56 606.11 654.16 744.09

M1000 (g) 860.00 980.00 1120.00 1320.00 1600.00

Sphericity: The values of sphericity were calculated individually with Eq. (2) by using the data on geometric mean diameter and the length of the seed and the results obtained are presented in Table 1. The sphericity (Ø) of the Hura crepitans seed increased from 0.63 to 0.69 mm as the moisture content increased from 9.3 to 52.5% (w.b.). The trend is as shown in Figure 3. The lower sphericity is an indication that the seed cannot roll on its side but slide. This is very useful in the design of handling equipment for the seed. Similar trends of increase was reported by Sessiz et al. (2007) for caper fruit while Çalişir et al. (2005) and Tavakoli et al. (2009) reported a decrease in sphericity for Turkey okra seed and soya bean seed respectively. The regression equation is as shown below: Ø=2e-0.5Mc2 +e-0.5Mc +0.628 (R2= 0.99) (16)

Surface Area: The surface area of the Hura Fig. 1: Effect of moisture content on the Principal crepitans seed was calculated using Eq.3. The result dimensions of Hura crepitans seed is as presented in Table 1. The surface area of the seed increased from 522.55 to 744.09 mm2 when the moisture content increased from 9.3 to 52.4% ( w.b). The result was as shown in Fig. 4. Similar trend has

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been reported by Selvi et al. (2006) for linseed, Ișik and Ünal (2007) for red kidney bean grains, and Garnayak et al. (2008) for jatropha seed .Regression analysis was performed on the effect of moisture content on surface area of Hura Crepitans. The relationship is as shown below in equation 17. 2 2 Sa=0.069Mc +0.626Mc+514.8 (R =0.991) (17) Volume: The volume of Hura crepitans seed showed the marked variation with the moisture content in the range from 9.3% to 52.4% w.b. as shown in Table 1. The volume of seeds increased from 758.38 to 1345.13 mm3. The correlation graph is shown in Fig 5. Similar increasing trend has been reported by Baryeh, (2002) for millet, Çalişir et al, (2005) for Turkey okra seed and Sessiz et al. (2007) for caper fruit. The regression equation on the effect of moisture content on the volume of Hura crepitans seeds is as shown below: 2 2 V = 0.211Mc + 0.023Mc + 749.8 (R = 0.991) (18)

Fig.3: Effect of moisture content on Sphericity of Hura crepitans seeds

Fig.2: Effect of moisture content on geometric mean Diameter of Hura crepitans seeds

Fig. 4: Effect of Moisture content on Surface Area of Hura crepitans seeds

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trends of increase has been reported for Turkey okra seed (Çalişir et al., 2005), caper fruit (Sessiz, 2007), karanja kernel (Pradhan et al., 2008) and soya bean seed (Tavakoli et al., 2009). Effect of moisture content on the thousand seed mass was found to be related as shown below: 2 2 1000m=0.280Mc +0.335Mc+842.0(R =0.999) (19) Relationship between the seed and kernel Physical properties: From Table 2, the size distribution showed that about 56% of the seed by number and 50% by mass were of medium size, 18% by number and 29% by mass were large and 26% by number and 31% by mass were small seeds. Larger seeds were broader but not as thick and heavy as the medium and small ones. The following expression was developed to describe the relationship among the dimensions of the seed. L = 0.97 W= 4.07 T = 486.19 M (20) About 56% of the kernels were of medium size, while Fig.5: The effect of Moisture content on the volume 14% were large and 30% small. This shows that most seed of Hura crepitans of the kernels are medium sized as the seeds. The kernel shows the following relationship and the dimensions. l = 0.92 w = 3.39 t = 522.67 m (21) The general expressions that can also be used to describe the relationship between the dimensions of Hura crepitans seed and kernel: L= 1.30 l (22) W= 1.24 w (23) T= 1.09 t (24) M= 1.45 m (25) Where L is length of seed (mm), W is width of seed (mm), T is thickness of seed (mm), M is mass of seed while l is length of kernel (mm), w is width of kernel (mm), t is thickness of kernel (mm) and m is mass of kernel.

In Table 3, the L/W ratio is lower than the L/T and Fig. 6: Effect of moisture content on one thousand L/M ratios; meaning that the width of the seed is seed mass of Hura crepitans seeds higher than its length and this is also the same for the kernel. This is very useful in the design of a grading and cleaning machine for the seed. Thousand seed mass: The thousand seed mass of Hura crepitans increased from 860 to 1600 g as the moisture content increased from 9.3 to 52.5% w.b. (Table 1). Figure 6 shows the relationship. Similar

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Table 2: Compare of Physical properties of Hura crepitans seeds and its kernels Property Unit No of replicates Seeds at 9.3% Mc (w.b.) Kernels at 9.3% Mc (wb) (w.b.) Length mm 100 20.42 15.68 Width mm 100 21.11 16.96 Thickness mm 100 5.02 4.62 Equivalent Dia mm 100 12.89 10.69 Sphericity mm 100 0.63 0.68 Volume mm3 100 758.38 454.01 Surface area mm2 100 522.55 358.88 Mass g 100 0.084 0.058 True density g/cm3 5 13.40 6.00 Bulk density g/cm3 5 0.55 0.56 Porosity % - 95.9 90.60 Table 3: Dimension ratio of H. crepitans seed and values confirm that there is a low variation between kernel the principal dimensions of both the shelled and Parameters Mean unshelled materials; hence, the seed cannot be L/W 0.97 classified as spherical in shape so during the design L/T 4.07 of the handling equipments the seed will slide but not L/M 486.19 roll. l/w 0.92 The average seed mass of Hura crepitans seed and l/t 3.39 kernel were 0.080 g and 0.058 g respectively. These l/m 540.69 are higher than that of sponge gourd seeds. This L/l 1.30 indicates that Hura crepitans seeds are slightly W/w 1.24 heavier. The average true and bulk densities of the T/t 1.09 seed are 13.4 g/cm3 and 0.55 g/cm3 while the M/m 1.45 corresponding values for the kernel are 6.0 g/cm3 3 and 0.56 g/cm . Porosity values for Hura crepitans seed and kernel are 95.9 and 90.6%. The average values of geometric mean diameter, sphericity, volume and surface area of the seed were Mechanical properties: The result of experiment on 12.89 mm, 0.63 mm, 758.38 mm3 and 522.55 mm2 angle of repose and coefficient of friction carried out respectively and the corresponding values for the on Hura crepitans were represented in Table 4. 3 kernels were 10.69 mm, 0.68 mm, 451.01 mm , 358.88 mm2 respectively (Table 2). These high

Table 4: Mechanical properties of H. crepitans seed and kernel Property unit No of replicates Seed Kernel Coefficient of friction Galvanized steel decimal 5 0.39 0.52 Mild steel 5 0.36 0.54 Aluminum 5 0.39 0.52 Stainless steel 5 0.32 0.43 Plywood 5 0.37 0.66 Angle of repose 5 19.2 26.2 must be a little modification in the design of storage Angle of repose: The angle of repose of the seeds equipments for the two. and kernels on wood was 19.2o and 26.26o Coefficient of friction: The coefficient of friction of respectively. This showed that the kernels are not as Hura crepitans seeds and kernels were 0.39and0.52 smooth as the seeds. A similar observation was on galvanized steel, 0.35 and 0.54 on mild steel, 0. reported for sponge gourd seed (Ogunsina et al., 39 and 0.52 on aluminum, 0.32 and 0.43 on 2009). The wide range between the angle of repose stainless steel and 0.37 and 0.66 on plywood, of seed to that of kernel is an indication that there respectively. This result is within the results of

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Irtwange and Igbeka (2002) for African yam bean and Kaleemullah, S., and Gunasekar, J.J. 2002. Moisture- Oje and Ugbor (1991) for oilseed bean. dependent physical properties of arecanut kernels. Biosystems Engineering Research, 25, 75-86. Conclusion: Having carried out investigations on the effect of moisture content on engineering properties Mohsenin, N.N. 1986. Physical properties of plant and animal materials (end ed.). New York, NY: Gordon of Hura creptance seed, it was discovered that all the and Breach Science Publishers. linear dimensions, mass, volume, porosity and bulk density increased with increase in moisture content in Ogunjimi, L.A.O., Aviara, N.A., and Aregbesola, O.A. 2002. the range of moisture content investigated. The Some engineering properties of locust bean seed. Journal of Food Engineering, 55, 95-99. findings from the research shows good agreement with some of the general trend and ranges obtained Ogunsina, B.S., Olaoya, I.O., Opeyemi, O.O., and for other similar crops. It is of opinion that data from Adegbenjo, A.O. 2009. Some nutritional, physical and mechanical properties of sponge gourd seeds. this test will be useful in the design and development rd of the appropriate machines for handling and Journal of Proceedings of 3 International Conference of WASAE and 9th Conference of NIAE, processing of the seed. January 25-29, 2009, Ile-Ife, Nigeria. REFERENCES Olaoye, J.O. 2000. Some physical properties of castor nut Aviara, N.A., Gwandzang, M.I., and Haque, M.A. 2009. relevant to design of processing equipment. Journal Physical properties of guna seeds. Journal of of Agricultural Engineering Research, 77 (1), 113- Agricultural Engineering Research, 73 (2), 105-111. 118. Baryeh, E.A. and Mangope, B.K. 2002. Some physical Oje K. and Ugbor E C (1991).Some physical properties of properties of QP-38 variety pigeon pea. Journal of oil bean seed. Journal of Agricultural Engineering Food Engineering, 56, 59-65. Research, 50(4), 305-313 Burubai, M., Amula, W.E., daworiye, P., Suowari, T., and Omobuwajo, T.O., Akande, E.A., and Sanni, L.A. 1999. Niame, P. 2006. Proximate compositions and Selected physical, mechanical and aerodynamic some technological properties of African nutmeg properties of African breadfruit seeds. Journal of Food seeds. Department of Agricultural Engineering, 40, 241-244. Engineering, Rivers State University of Science and Owolarafe, O.K., Olabige, M.T., and Faborode, M.O. 2007. Technology Nigeria. Physical and mechanical properties of pearl millet. Calisir, S., Ozcan, M., Haydar, H., and Yildiz, M.U. 2005. A Journal of Agricultural Engineering Research, 66, 85- study on some physico-chemical properties of 91. Turkey okra seeds. Journal of Food Engineering, 68, Ozguven, F., and Vursavus, K. 2005. Some physical, 73-78. mechanical and aerodynamic properties of pine nuts. Dutta, S.k., Nema, V.K. and Bhardwaj, R.J. 1988. Physical Journal of Food Engineering, 68, 191-196. properties of gram. Journal of Agricultural Pradhan, R.C., S.N. Naik, N. Bhatnagar, and S.K. Swain. Engineering Research, 39, 259-268. 2008. Moisture-dependent physical properties of Garnayak, D.K., R.C. Pradhan, S.N. Naik, and N. karanja (Pongamia pinnata) kernel. Industrial Crops Bhatnagar. 2008. Moisture-dependent physical and Products, 28(2), 155-161. properties of Jatropha seed (Jatropha curcas L.). Selvi, K.C., Y. Pinar, and E. Yesiloglu. 2006. Some Industrial Crops and Products, 27, 123- 129. physical properties of linseed. Biosystems Gupta, R.K., and Das, S.K. 1997. Physical properties of Engineering, 95 (4), 607-612. sunflower seeds. Journal of Agricultural Engineering Sessiz, A., Esgici, R., and Kizil, S. 2007. Moisture- Research, 66, 1-8. dependent physical properties of caper fruit. Journal Irtwange S V and Igbeka J C. 2002.Some physical of Food Engineering, 19, 1426-1431. properties of two African yam bean (Sphenostylis Tavakoli, H., Rajabipour, A., Mohtasebi S.S. 2009. Some stenocarpa) accessions anad their interrelationships moisture-dependent engineering properties of with moisture content. Applied Engineering in soybean grains. Agricultural Engineering Agriculture, 18(5), 567-576 International: the CIGR Ejournal. Manuscript 1110. Isik, E. and H. Unal. 2007. Moisture-dependent physical Vol. XI. properties of white speckled red kidney bean grains. Wikipedia Encyclopedia. Hura crepitans. Journal of Food Engineering, 82, 209-216. www.wikipedia.org/wiki/wikipedia.2006., Accessed on th Jain, R.K., and Bal,S. 1997. Physical properties of pearl January, 29 2009. millet. Journal of Agricultural Engineering Research, 66, 85-91.

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