DOCSLIB.ORG

Fundamental Tests on Carbon Dioxide Sequestration Into

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

FUNDAMENTAL TESTS ON CARBON DIOXIDE SEQUESTRATION INTO COAL SEAMS K. Ohga1), K.Sasaki2),G. Deguchi3) and M.Fujioka3) 1) Graduate School of Hokkaido University 2) Akita University 3) Japan Coal Energy Center ABSTRACT Recently, carbon dioxide injection into coal seams has become of major interest as one method of carbon dioxide sequestration; sequestration into coal seams is more advantageous than other geo-sequestration because of the following points; 1) the principal of this sequestration is due mainly to the action of gas adsorption to the coal, therefore carbon dioxide injected into the coal seam is fixed firmly. 2) When carbon dioxide is injected into coal seams, methane can be recovered as a by-product. This will reduce the cost of sequestration. The fundamental research group carried out various laboratory tests, which were adsorption tests of carbon dioxide and methane, replacement tests of methane by carbon dioxide and adsorption tests of coal samples treated by carbon dioxide under supercritical condition. Taiheiyo Coal and Akabira Coal were used in these tests. From the results, it is clear that there is a big difference in adsorption volume of methane between Taiheiyo Coal and Akabira Coal, but there is no difference in carbon dioxide adsorption volume between them at low pressure. In this paper, we will describe the results of other tests. INTRODUCTION Fig.1 shows the main coal fields and coal mines in Japan. There are seven main coal fields. At the end of last year, the Matsushima coal mine in Kyushu was closed and in the beginning of this year, the Taiheiyo Coal Mine was closed; the name of coal mine was then changed from the Taiheiyo to the Kushiro Coal Mine and it was re-established. The mining area of this mine was moved from a deeper to a shallower area. Blue characters in this figure indicate the name of coal fields and red figures indicate coal resources of the coal fields. Most of the coal fields are in Kyushu and Hokkaido. More than 50% of coal is in Hokkaido and the most gassy coal field, which is the Ishikari coal field, is in the center of Hokkaido. The permeability of coal seam of the southern part of the Ishikari coal field is one of highest levels in Japanese coal fields. It is one of the sites proposed for CO2 injection into a virgin coal seam. In order to understand Greenhouse Gas Control Technologies, J. Gale and Y. Kaya (Eds.) © 2003 Elsevier Science Ltd. All rights reserved the mechanism of replacement of methane absorbed on the internal surface of coal by carbon dioxide, we carried out the following tests: 1) adsorption tests using carbon dioxide, methane and nitrogen, 2) replacement tests of methane by carbon dioxide and gas mixtures. 3) adsorption tests of coal samples treated with carbon dioxide under supercritical condition. The coal samples collected in the Ishikari and Kushiro Coal Fields were used. COAL SAMPLES Coal samples used in the absorption tests by pure gases and replacement tests by mixted gases were collected from the No.8 coal seam at Akabira Coal Mine in the Ishikari coal field. To compare the absorption volume and replacement ratio, coal samples collected from the main coal seam at Taiheiyo coal in the Kushiro coal field were used. The space of cleats of the No.8 coal seam was about 2- 4mm. Therefore, the coal samples were crushed and screened to between 4 and 8 mesh. EQUIPEMENT Fig.2 shows the equipment used for the adsorption tests and the replacement tests. The equipment consisted of a reaction vessel (I) to absorb gas on the coal sample and a buffer tank (G) to measure the injection gas volume to the reactor vessel. Pressure sensors (D1,D2) were installed on the reaction vessel and the buffer tank. The injection gas volume into the reaction vessel and released gas were calculated from the change of pressure in the buffer tank, and absorption volume into the coal sample was calculated from the change of the pressure in the reaction vessel. To reduce the effect of temperature change, the whole equipment was placed in a water bath (I) as shown in Fig.2. The temperature of the water was kept at 20C by the temperature controller (J). About 50g of coal sample was put into the Reaction Vessel (H). Released gas was analyzed by gas-chromatography. ADSORPTION TESTS Adsorption tests using carbon dioxide, methane and nitrogen were carried out using the following procedures: To remove the adsorbed gas on the coal sample, gas in the reaction vessel is sucked by a vacuum pump at 40oC, for 24 hours. After this, gas is injected into the buffer tank and the reaction vessel until the pressure in the reaction vessel reached a specified level; measurement of the adsorption gas volume at certain pressure is then carried out. The adsorption volumes are measured under pressure. Fig.3 shows the results of these tests by each gas. The circle line indicates the carbon dioxide adsorption isotherm. The triangle and square lines indicate the methane adsorption isotherm and nitrogen adsorption isotherm, respectively. From the results, the adsorption volume of carbon dioxide on the Akabira coal is three times as much as the methane one, and the adsorption volume of nitrogen is half of the methane adsorption. Greenhouse Gas Control Technologies, J. Gale and Y. Kaya (Eds.) © 2003 Elsevier Science Ltd. All rights reserved REPLACEMENT TESTS Methane replacement tests by carbon dioxide and mixtures of carbon dioxide and nitrogen was carried out as following procedures; the adsorbed gas on the coal sample is removed by a vacuum. Then, methane is injected into the reaction vessel to adsorb methane on the coal sample at about 1Mpa. After the pressure in the reaction vessel reaches the equilibrium pressure, gas in the reaction vessel is released. After the pressure in the reaction vessel reaches atmospheric pressure, carbon dioxide or mixtures of carbon dioxide and nitrogen are injected into the reaction vessel at 0.2Mpa. When the pressure in the reaction vessel reached the equilibrium pressure, the gas in the reaction vessel is released and its gaseous content analyzed by gas-chromatography. Fig.4 shows the results of the tests. From the results, when carbon dioxide concentration increases, the volume of carbon dioxide adsorption increases, the volume of methane adsorption decreases and nitrogen is unchanged. Fig.5 shows the results of replacement tests using Taiheiyo and Akabira coals. From the results, Akabira coal adsorbs methane more than Taiheiyo coal. From the measurement results, the methane replacement ratio and carbon dioxide sequestration ratio are calculated by the following equations: Methane Replacement Ratio =(A-B)/A x 100% Where, A; amount of methane adsorption on coal sample at the atmospheric pressure. B; amount of methane adsorption on coal sample at the atmospheric pressure after replacement. Carbon Dioxide Sequestration Ratio= D/C x 100% Where, C; amount of injected carbon dioxide D; amount of carbon dioxide adsorption after released gas. The results are shown in Table 1. TABLE 1 RESULTS OF REPLACEMENT TESTS CH4 Replacement Ratio (%) CO2 Sequestration Ratio (%) CO2(100%) 57.5 55.8 CO2(30%) N2(70%) 17.3 67.4 CO2(10%) N2(90%) 7.1 69.2 As a result, it was found that the higher ratio of sequestration to coal can be obtained when the lower concentration of carbon dioxide is injected, while methane replacement ratio decreases with decrease of carbon dioxide concentration. There is a big difference between methane replacement ratios, but there is no difference between carbon dioxide sequestration ratios. ESTIMATION OF ADSORPTION VOLUM UNDER MIXED GASES We tried to estimate the adsorption volume of each gas under a mixture of methane, carbon dioxide and nitrogen by using the Markham-Benton equation which is extended langmur equation for three mixed gases. I t is expressed as follows; K y Z = A A A + + K A y A K B yB K C yC Greenhouse Gas Control Technologies, J. Gale and Y. Kaya (Eds.) © 2003 Elsevier Science Ltd. All rights reserved Where, ZA expresses molar fraction of gas A in adsorption phase. YA expresses molar fraction of gas A in gas phase. KA(0.08), KB(0.0298) and KC (0.0027) were calculated from the results of adsorption tests by pure gases. Table 2 shows the molar fraction of each gas in the each phase calculated by the results of replacement tests and estimation molar fraction calculated by using Markham- Benton Equation. There is no difference between the results of replacement tests and estimation results by Markham-Benton equation. COAL SAMPLES TREATED BY CO2 UNDER SUPERCRITICAL CONDITIONS In the case where carbon dioxide is injected into deeper coal seams, it is considered that the temperature and the pressure during injection is greater than the supercritical condition of carbon dioxide, and after injection is stopped, the injected gas diffuses into the coal seam and the pressure drops under supercritical conditions of carbon dioxide. TABLE 2 CO2 100% CH4 CO2 N2 Molar fraction in Gas Phase 0.69 0.31 Molar Fraction in Adsorption Phase 0.45 0.55 Estimation Molar Fraction by Markham-Benton 0.45 0.45 CO2(30%)-N2(70%) Molar fraction in Gas Phase 0.59 0.05 0.35 Molar Fraction in Adsorption Phase 0.82 0.23 0.0 Estimation Molar Fraction by Markham-Benton 0.79 0.18 0.03 CO2(10%)-N2(90%) Molar fraction in Gas Phase 0.40 0.02 0.58 Molar Fraction in Adsorption Phase 0.86 0.12 0.03 Estimation Molar Fraction by Markham-Benton 0.79 0.11 0.10 Therefore, we conducted adsorption tests and replacement tests using coal samples which were treated by carbon dioxide under supercritical condition.
Recommended publications
  • Support for Workers Displaced in the Decline of the Japanese Coal Industry: Formal and Informal Support Naoko Shimazaki Waseda University

    Support for Workers Displaced in the Decline of the Japanese Coal Industry: Formal and Informal Support Naoko Shimazaki Waseda University

    Support for Workers Displaced in the Decline of the Japanese Coal Industry: Formal and Informal Support Naoko Shimazaki Waseda University Japan’s coal industry met its demise following a number of stages of restruc- turing under policies to change the structure of the energy industry. More than 200,000 coal mine workers were displaced from 1955 onward. The task of providing measures for displaced workers was recognized as an issue to be addressed at national level and such initiatives were considered to have con- siderable significance for the interests of society as a whole. This led to the development of substantial support systems of the kind not seen in other in- dustries, and comprehensive measures were adopted to cover not only reemployment, but also relocation, housing, and vocational training. However, fundamental issues faced by the unemployed were left unresolved. Formal support therefore in fact relied on the strength of individual companies and re- gional communities, and developed distinct characteristics. The insufficiencies of the formal support systems were compensated for by informal support based on personal relationships which were characteristic of the unique culture of coal mining. In particular, there was a strong sense of solidarity among fel- low mine workers. The support for displaced workers included not only finan- cial assistance, but also individual support, such as individual counselling and employment assistance provided by former coal mine employees acting as counselors. The labor unions played a central role in developing these measures. Such support was very strongly in tune with the workers’ culture generated within coal mining communities. I. Coal Policy and Measures for Displaced Workers in Japan The coal industry is a typical example of industrial restructuring in Japan.
  • External Dose Data

    External Dose Data

    External Dose Data External Exposure due to Natural Radiation [National Institute of Radiological Sciences) surveymeter were used for measurement of given A field survey of exposure rates due to natural stations and their readings are compared for drawing a radiation has been conducted throughout the Hokkai­ relationship between them. do district of Japan during June 1971. Practically the direct reading of the thsurveymeter The situation of the Hokkaido district in Japan is were reduced into the reading of the plastic chamber shown in Figure 1. Distribution of observed locations corresponding to it from the relationship of linear in the district is indicated in Figure 2. In each location, proportion. Systematic error at culiblation (60Co) and from one to five sites containing at least 5 stations uading error (random) of the pfastic chamber were were made there. A total of 81 sites were measured. respectively within ±6 % (maximum over all error) and Observations were made using a spherical ioniza­ within ±3.5 % (standard error for 6jLtR/hr). Reading error tion chamber and several scientillation surveymeters. error of the survey-meter is about ±3%. (standard error The spherical plastic ionization chamber of which inner for 6juR/hr) diameter and wall thickness are respectively 200 mm Measurements in open bare field were made at one and 3 mm (acrylate) has adequate sensitivity for field meter above the ground and outdoor gamma-rays survey. The chamber was used as a standard of exposure rates (juR/hr) were due to cosmic rays as well apparatus, but it is difficult to observe all locations as terrestrial radiation, so that it may be considered only by the apparatus, so that a surveymeter with a that the contribution of fallout due to artificial origin Nal (Tl) Y'<p x 1" scintillator was used for regular was very slight.
  • Hokkaido Map Scenic Spots in the Kamikawa Area

    Hokkaido Map Scenic Spots in the Kamikawa Area

    Cape Soya Wakkanai Rebun Island Wakkanai Airport Scenic spots in the Kafuka Oshidomari Kamikawa area Mt. Rishiri Hokkaido Map ▲ Rishiri Nakagawa/Aerial photo of Teshio River Saku Otoineppu/The place that Hokkaido was named Rishiri Island Toyotomi Onsen (Mizukiri Contest (Stone-skipping Contest)) in July Airport Toyotomi Nakagawa Otoineppu Etorofu Island 40 Bifuka/Farm inn tonttu Horokanai/Santozan Mountain Range Shibetsu/Suffolk Land Kenbuchi/Nano in July Wassamu/A street lined with white birch in winter Bifuka Yagishiri Chiebun Sunflower fields● ●Nayoro Onsen Teuri Okhotsk Island Island Haboro Nayoro Mombetsu Lake Shumarinai Shimokawa Monbetsu ●Icebreaker Airport "Garinko-go" ●Takinoue Park Shiretoko Peninsula Kamiyubetsu World Sheep Museum● Shibetsu Tulip Park ● Takinoue Lake Saroma Nayoro/Sunflower fields Shimokawa/Forest in winter Asahikawa/Kamuikotan Library of picture books● Mt. Rausu Kenbuchi ▲ Engaru Lake Notoro Wassamu Horokanai Mt. Teshio Abashiri Utoro Onsen Rausu ▲ Maruseppu Lake Abashiri Rumoi Takasu Pippu ●Maruseppu Abashiri-Kohan Onsen Kunashiri Island Onsen Shiretoko-Shari Mashike Aibetsu Memanbetsu ●Tohma Limestone cave Airport Kitami Snow Crystal Museum● Tohma Kamikawa ● Shikotan Island Asahiyama Zoo 39 ▲ Asahikawa Asahikawa Mt. Shari ▲ 237 Airport Sounkyo Onsen Mt. Shokanbetsu 39 Onneyu Onsen Higashikagura Kawayu Onsen ▲ Asahidake Onsen Lake Kussharo Higashikawa Mt. Asahidake Tenninkyo Onsen Habomai Islands Takikawa Ashibetsu Biei Takasu/Palette Hills in May Pippu/The top of Pippu Ski Area in Jan. Aibetsu/Kinokonosato park golf course in May Shirogane Onsen ▲ Lake Mashu Shintotsukawa Kamifurano Mt. Tomuraushi Lake Akan Mashu Nakashibetsu Airport 12 Akan Mashu Cape Shakotan Nakafurano ▲ Akanko Onsen Mt. Tokachi Nukabira Onsen ▲ Onsen Mt. Oakan Bibai Furano Nemuro Cape Kamui Nemuro Peninsula Ishikari Bay 44 Otaru Iwamizawa 38 Ashoro Minamifurano Yoichi Sapporo ▲ Hoshino Resorts Shiranuka Yubari Mt.
  • Thorough Guidebook of Lively Experience in Kushiro

    Thorough Guidebook of Lively Experience in Kushiro

    Thorough Guidebook of Lively Experience in Kushiro A タイプ Map of East Hokkaido 知床岬 Cape Shiretoko 知床岳 Mt.Shiretoko-dake 知床国立公園 Shiretoko National Park 網走国定公園 カムイワッカの 滝 Abashiri Quasi-National Park Kamuiwakka Hot Water Falls 硫黄山 Mt.Io サロマ湖 知床五湖 Lake Saroma 能取岬 Cape Notoro Shiretoko Five Lakes 羅臼町 93 238 RausuTown ウト ロ 羅臼岳 87 道の駅「サロマ湖」 Utoro Mt.Rausu-dake Michi-no-Eki(Road Station)Saromako 知床横断道路 7 能取湖 76 網走市 334 佐呂間町 Lake Abashiri City オシンコシンの滝 冬期通行止 Saroma Town 103 Shiretoko Crossing Road Notoro 道の駅「流氷街道網走」 Oshinkoshin Falls Closed in Winter Michi-no-Eki(Road Station) 道の駅「知床・らうす」 Ryuhyo kaido abashiri Michi-no-Eki(Road Station) Shiretoko Rausu 網走湖 Lake Abashiri 334 道の駅「うとろシリエトク」 小清水原生花園 Michi-no-Eki(Road Station)Utoro Shirietoku Koshinizu Natural Flower Gaden 道の駅「メルヘンの丘めまんべつ」 333 Michi-no-Eki(Road Station)Meruhen no Oka Memanbetu 斜里町 104 大空町 244 Shari Town Oozora Town 道の駅「はなやか小清水」 道の駅「しゃり」 7 女満別空港 Michi-no-Eki(Road Station)Hanayaka Koshimizu Michi-no-Eki(Road Station)Shari 39 Memanbetsu Airport 102 道の駅「パパスランドさっつる」 Michi-no-Eki(Road Station) 335 334 Papasu Land Sattsuru 391 122 清里町 244 北見市 243 小清水町 Senmo Line 釧網本線Kiyosato Town Kitami City 美幌町 Koshimizu Town 斜里岳 50 Bihoro Town 津別町 102 Mt.Sharidake Tsubetsu Town 斜里岳道立自然公園 Sharidake Prefectural Natural Park 標津サーモンパーク 27 藻琴山 Shibetsu Salmon 143 Mt.Mokoto Scientific Museum 道の駅「ぐるっとパノラマ美幌峠」 野付半島 Michi-no-Eki(Road Station) 開陽台展望台 ClosedGrutto in WinterPanorama Bihorotouge Notsuke Peninsula Kaiyoudai 根室中標津空港 272 240 冬期通行止 屈斜路湖 Observatory NemuroNakashibetsu 野付湾 Lake Kussharo Airport Notsuke Bay
  • H O K K a I D O S O R a C

    H O K K a I D O S O R a C

    HOKKAIDO SORACHI Hokkaido Sorachi Regional Creation Conference Contact Sorachi General Subprefectual Bureau ℡:＋81-126200185 Email:[email protected] November,2018 What is Sorachi ? 1 Located in the inlands of Hokkaido An area that holds 24 cities and towns. Located in the center of Hokkaido, with good access to New Chitose Airport, Asahikawa Airport, and Sapporo. JR Minimum time 1 hr. and 5 min. New Chitose Airport – Iwamizawa Car Hokkaido Expressway ・New Chitose IC-Iwamizawa IC ・ General roads / approx. 65 min. JR Minimum time 24 min. Iwamizawa – Takikawa Car Hokkaido Expressway ・Iwamizawa IC - Takikawa IC ・ General roads / approx. 40 min. JR Minimum time 13 min. ●Transportation Takikawa – Fukagawa Car Hokkaido Expressway ・Takikawa IC - Fukagawa IC ・ General roads / approx. 25 min. information JR Minimum time 19 min. Fukagawa – Asahikawa ・ Car Hokkaido Expressway ・Fukagawa IC – Asahikawa Takasu IC ・ General roads / approx. 40 min. JR http://www2.jrhokkaid JR Minimum time 24 min. o.co.jp/global/index.ht Sapporo – Iwamizawa Car Hokkaido Expressway ・Sapporo IC – Iwamizawa IC ・ General roads / approx. 45 min. ml JR Minimum time 54 min. Furano – Takikawa ・Hokkaido Chuo Bus Car General roads / approx. 1hr. and 10 min. http://teikan.chuo- JR Minimum time 1 hr. and 25 min. bus.co.jp/en/ Furano – Iwamizawa Car General roads / approx. 1hr. and 25 min. 自 然 Flower gardens blooming from spring to autumn. 2 N a t u r e ●Rape Blossom Fields ●Yuni Garden(Yuni) British style garden where you can watch (Takikawa) various flowers from spring to autumn. Especially the Linaria in late June, and Canola flowers with one of the cosmos blooming from September the leading acreage area in are magnificent.
  • Hokkaido Research Organization Fisheries Research Department, Hokkaido Research Organization

    Hokkaido Research Organization Fisheries Research Department, Hokkaido Research Organization

    Cover photos (Upper left) - Fries of Salmon and catching autumn Salmons by stationary netting at Abashiri offshore * The photo of catching by courtesy of Mr. Masami Takahashi, Fisheries Graph K. K. (Upper right) - The larvae of scallop immunostained and catching scallops by girder seine fishery at Monbetsu offshore. (Lower left) - Eggs of Pacific herrings, on seaweeds at Otaru offshore. (Lower right) - Catching of Pacific herrings using the gill net, at the Atsuta fishery port Local Independent Administrative Agency Fisheries Research Department, Guide of the Local Independent Administrative Agency, Hokkaido Research Organization Fisheries Research Department, Hokkaido Research Organization Marin net Hokkaido website http://www.fishexp.hro.or.jp/ Published by Fisheries Research Department, Hokkaido Research Organization Planned and Edited by Planning and Coordination Division, Fisheries Research Department, Hokkaido Research Organization Central Fisheries Research Institute Wakkanai Fisheries Research Institute Printed by the Social Welfare Corporation, Hokkaido Rehabily Mariculture Fisheries Research Hakodate Fisheries Research Institute Date of issue: October 2010 Institute Kushiro Fisheries Research Institute Salmon and Freshwater Fisheries Research Institute Abashiri Fisheries Research Institute Introduction Apr., 1948 The Hokkaido Salmon Hatch Station, Teshio Branch Station was established. Mar., 1950 The fishery training centers of Shana and Abashiri were disused. Hokkaido is an island of an extensive area endowed with lakes and marshes in the rich natural environment, and is Apr., 1950 Trough the remodeling of the state-owned fishery research organization, the Hokkaido Fisheries Research Institute was divided into two surrounded by 3 seas, the Pacific Ocean, the Sea of Japan and the Sea of Okhotsk, respectively owing their unique organizations, the Hokkaido District Fisheries Research Institute of the Fisheries Agency and the Hokkaido-owned Fisheries Research characteristics.
  • Our Research Realizes New Dreams for Hokkaido

    Our Research Realizes New Dreams for Hokkaido

    Hokkaido Research Organization Our research realizes new dreams for Hokkaido. http://www.hro.or.jp/ Message from the President Yoshikatsu Tanaka The Hokkaido Research Organization (HRO), a local independent administrative agency, was established in April 2010 by integrating 22 prefectural research institutes in the fields of agriculture, fisheries, forestry, manufacturing, food, environment, geology and architecture. The HRO is now focused on the three fields of food, energy and communities under the second midterm plan, which began in 2015, and utilizes its accumulated technologies and expertise while demonstrating its collective strengths in various fields to promote research on fundamental technologies that enhance the basic value of the technologies owned by Hokkaido industries and the effectiveness of administrative policies. It also works toward the practical use of fundamental technologies, contributing to the improvement of residents' living standards and the promotion of local industries as a comprehensive research institute in Hokkaido. Meanwhile, changes in socioeconomic circumstances and revolutionary advancement in scientific technology, such as the depopulation and aging of the population in Hokkaido at a faster pace than the national averages, worsening resource/energy problems, rapid development in ICT including IoT and big data, and advancing globalization, have various effects on the Hokkaido economy and lives of Hokkaido residents. To timely and appropriately deal with such powerful trends and promote research and development for the future, we are preparing the third midterm plan, which will begin in FY 2020. While defining the future vision, we will further strive to conduct high-value research and development that are used for the lives of Hokkaido residents and industries.
  • Effect of Sasa Invasion on CO2, CH4 and N2O Fluxes in Sphagnum Dominated Poor Fen in Bibai, Hokkaido, Japan

    Effect of Sasa Invasion on CO2, CH4 and N2O Fluxes in Sphagnum Dominated Poor Fen in Bibai, Hokkaido, Japan

    ©Verlag Ferdinand Berger & Söhne Ges.m.b.H., Horn, Austria, download unter www.biologiezentrum.at Phyton (Austria) Special issue: Vol. 45 Fasc. 4 (319)-(326) 1.10.2005 "APGC 2004" Effect of Sasa Invasion on CO2, CH4 and N2O Fluxes in Sphagnum Dominated Poor Fen in Bibai, Hokkaido, Japan By F. TAKAKAI0, O. NAGATA2)& R. HATANO3) Key words: Gas exchange, greenhouse gas, Sasa invasion, Sphagnum, poor fen. Summary TAKAKAI F., NAGATA O. & HATANO R. 2005. Effect of Sasa invasion on CO2, CH4 and N2O fluxes in Sphagnum dominated poor fen in Bibai, Hokkaido, Japan. - Phyton (Horn, Austria) 45(4):(319)-(326). In Hokkaido, the northern part of Japan, degradation of natural wetland is occurring due to invasion of Sasa vegetation associated with construction of drainages. We measured greenhouse gas (GHG) fluxes at the Sasa invaded wetland in Bibai, Hokkaido. GHG fluxes at Sphagnum-dominated site (Sp) and Sasa invasion site (Sa) were measured by using a closed chamber method (transparent acryl chamber which covering plants) from July to October 2002. GHG concentration profiles, air filled porosity, and gas diffusion coefficient (D/Do) of topsoil were also measured. Water table depth was not significantly different between the sites. Air-filled porosity was significantly lower in Sa than in Sp (p = 0.03). D/Do was also lower in Sa than in Sp. CH4 emissions (mg C m"2 hr'1) were significantly lower in Sa (2.4 ± 0.64) than in Sp (3.7 ± 0.48) (p = 0.03), al- though Sa showed a higher CH4 concentration gradient at ground surface than that of Sp.
  • By Municipality) (As of March 31, 2020)

    By Municipality) (As of March 31, 2020)

    The fiber optic broadband service coverage rate in Japan as of March 2020 (by municipality) (As of March 31, 2020) Municipal Coverage rate of fiber optic Prefecture Municipality broadband service code for households (%) 11011 Hokkaido Chuo Ward, Sapporo City 100.00 11029 Hokkaido Kita Ward, Sapporo City 100.00 11037 Hokkaido Higashi Ward, Sapporo City 100.00 11045 Hokkaido Shiraishi Ward, Sapporo City 100.00 11053 Hokkaido Toyohira Ward, Sapporo City 100.00 11061 Hokkaido Minami Ward, Sapporo City 99.94 11070 Hokkaido Nishi Ward, Sapporo City 100.00 11088 Hokkaido Atsubetsu Ward, Sapporo City 100.00 11096 Hokkaido Teine Ward, Sapporo City 100.00 11100 Hokkaido Kiyota Ward, Sapporo City 100.00 12025 Hokkaido Hakodate City 99.62 12033 Hokkaido Otaru City 100.00 12041 Hokkaido Asahikawa City 99.96 12050 Hokkaido Muroran City 100.00 12068 Hokkaido Kushiro City 99.31 12076 Hokkaido Obihiro City 99.47 12084 Hokkaido Kitami City 98.84 12092 Hokkaido Yubari City 90.24 12106 Hokkaido Iwamizawa City 93.24 12114 Hokkaido Abashiri City 97.29 12122 Hokkaido Rumoi City 97.57 12131 Hokkaido Tomakomai City 100.00 12149 Hokkaido Wakkanai City 99.99 12157 Hokkaido Bibai City 97.86 12165 Hokkaido Ashibetsu City 91.41 12173 Hokkaido Ebetsu City 100.00 12181 Hokkaido Akabira City 97.97 12190 Hokkaido Monbetsu City 94.60 12203 Hokkaido Shibetsu City 90.22 12211 Hokkaido Nayoro City 95.76 12220 Hokkaido Mikasa City 97.08 12238 Hokkaido Nemuro City 100.00 12246 Hokkaido Chitose City 99.32 12254 Hokkaido Takikawa City 100.00 12262 Hokkaido Sunagawa City 99.13
  • A Generalized Goals-Achievement Model in Data Envelopment Analysis

    A Generalized Goals-Achievement Model in Data Envelopment Analysis

    TI 2008-110/3 Tinbergen Institute Discussion Paper A Generalized Goals-achievement Model in Data Envelopment Analysis Soushi Suzukia Peter Nijkampb a Hokkai-Gakuen University, Sapporo, Japan; b VU University Amsterdam, and Tinbergen Institute. Tinbergen Institute The Tinbergen Institute is the institute for economic research of the Erasmus Universiteit Rotterdam, Universiteit van Amsterdam, and Vrije Universiteit Amsterdam. Tinbergen Institute Amsterdam Roetersstraat 31 1018 WB Amsterdam The Netherlands Tel.: +31(0)20 551 3500 Fax: +31(0)20 551 3555 Tinbergen Institute Rotterdam Burg. Oudlaan 50 3062 PA Rotterdam The Netherlands Tel.: +31(0)10 408 8900 Fax: +31(0)10 408 9031 Most TI discussion papers can be downloaded at http://www.tinbergen.nl. A generalized goals-achievement model in data envelopment analysis: An application to efficiency improvement in local government finance in Japan Soushi Suzuki a Peter Nijkamp b aHokkai-Gakuen University, Department of Civil and Environmental Engineering, South26-West 11,1-1,chuo-ku, 064-0926 Sapporo, Japan bVU University Amsterdam, Department of Spatial Economics, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands Abstract Data Envelopment Analysis (DEA) has become an established tool in comparative analyses of efficiency strategies in both the public and the private sector. The aim of this paper is to present and apply a newly developed, adjusted DEA model – emerging from a blend of a Distance Friction Minimization (DFM) and a Goals Achievement (GA) approach on the basis of the Charnes-Cooper-Rhodes (CCR) method – in order to generate a more satisfactory efficiency-improving projection model in conventional DEA. Our DFM model is based on a generalized Euclidean distance minimization and serves to assist a Decision Making Unit (DMU) in improving its performance by the most appropriate movement towards the efficiency frontier surface.
  • Japanese Cranes by Kushiro the Japanese Tea Ceremony Usually Takes Place in a Traditional Japanese Tatami Room

    Japanese Cranes by Kushiro the Japanese Tea Ceremony Usually Takes Place in a Traditional Japanese Tatami Room

    Japanese Cranes by Kushiro The Japanese Tea Ceremony usually takes place in a traditional Japanese tatami room. Obihiro, Japan is located on the northernmost island of Japan, called Hokkaido . Students are flown to Chitose Airport in Sapporo , where they will usually spend the night in a hotel before traveling by bus to Obihiro to meet with homestays. Sometimes air travel takes them to Tokyo for an overnight stay before flying to Hokkaido. The bus ride itself takes about two and a half hours. They also may take a train from Sapporo to Obihiro. The city of Kushiro , east of Obihiro, also has a relationship with Seward, being our “Port Sister City.” Hokkaido is known for its cool summers (which attract many tourists from other parts of Japan) and icy winters. The average August temperature is around 22°C (72°F), while the average January temperature ranges from −12°C to −4°C (10°F to 25°F) depending on elevation and latitude. The island tends to see isolated snowstorms that develop long-lasting snowbanks, in contrast to the constant flurries seen in the Hokuriku region. During the winter, passage through the Sea of Okhotsk is often complicated by large ice floes broken loose from the Kamchatka Peninsula. Combined with high winds that occur during winter, this brings air travel and maritime activity almost to a halt on the northern coast of Hokkaido. It is Hokkaido's climate that has made it such a popular place for tourists from countries such as Australia. The other advantage is the ski season in Hokkaido is at the opposite time of year to that in Australia.
  • Eocene Ostracode Assemblages with Robertsonites from Hokkaido and Their Implications for the Paleobiogeography of Northwestern Pacific

    Eocene Ostracode Assemblages with Robertsonites from Hokkaido and Their Implications for the Paleobiogeography of Northwestern Pacific

    Bulletin of the Geological Survey of Japan, vol.59 (7/8), p. 369-384, 2008 Eocene ostracode assemblages with Robertsonites from Hokkaido and their implications for the paleobiogeography of Northwestern Pacific Tatsuhiko Yamaguchi1 and Hiroshi Kurita2 Tatsuhiko Yamaguchi and Hiroshi Kurita (2008) Eocene ostracode assemblages with Robertsonites from Hokkaido and their implications for the paleobiogeography of Northwestern Pacific. Bull. Geol. Surv. Japan, vol. 59, (7/8), 369-384, 6 figs., 2 tables, 2 plates, 1 appendix. Abstract: We report on Eocene ostracode species from Hokkaido, northern Japan for the first time and discuss their paleobiogeographic implications. Five species were found in the lower part of the Sankebetsu Formation in the Haboro area, and the Akabira and Ashibetsu Formations in the Yubari area, central Hokkaido. The ostracode assemblages are characterized by Robertsonites, a circumpolar Arctic genus of the modern fauna. This finding marks the southernmost occurrence of the Eocene record of the genus, as well as the oldest occurrence. As the characteristics of the Eocene Hokkaido fauna are similar to those of the modern-day fauna in the Seto Inland Sea, a contrast in species composition is observed between the Seto Inland Sea and Kyushu. This contrast is attributable to differences in sea temperature. Five species are described, including Robertsonites ashibetsuensis sp. nov. Keywords: Eocene, Hokkaido, Ostracoda, paleobiogeography, Robertsonites Seto Inland Sea were located around paleolatitudes of 1. Introduction approximately 33–34 °N and 37–38 °N, respectively We describe the systematics of Eocene ostracodes (Otofuji, 1996). This latitudinal separation between the from Hokkaido, northern Japan, for the first time and two areas would have led to faunal differences due to discuss their paleobiogeographic implications.