Archive - Abstract
Vol.48 No.1 (March, 2017)
- Research Paper (Japanese)
Development of a Cost-effective and Physically Strong Cathode, Composed of Stainless Steel and Polydimethylsiloxane, for the Use in Microbial Fuel Cells
- Shiho ASAKAWA, Atsuo IKEGUCHI, Takahiro YAMASHITA and Hiroshi YOKOYAMA
- A microbial fuel cell (MFC) is a device that simultaneously generates electricity and decomposes organic matters in wastewater. Commonly-used cathodes in MFCs are made of expensive materials, and are low in mechanical strength. Scale-up of MFC reactors has been hindered by the low physical strength of the cathode. Conventional cathodes are composed of carbon cloth containing Pt catalyst, fused with or without the proton exchange membrane, Nafion. In the present study, we report a new physically-strong cathode, made of cost-effective alternative materials, Selemion HSF membrane, stainless-steel mesh, and polydimethylsiloxane. Single-chambered MFCs (125 mL) equipped with the new cathode or conventional Nafion cathode were operated using an artificial wastewater containing peptone and beef extract. Coulombic efficiency of the MFCs with the new cathode was 23.9 – 27.7 %, which was significantly higher than that of the MFCs with the conventional cathode (5.9 – 11.1 %). The power density was similar levels between the MFCs with the new cathode (114.4 – 125.0 W/m2) and the conventional cathode (97.6 – 119.1 W/m2). The new cathodes displayed similar current productivities as compared to the conventional cathodes in a polarization test using a potentiostatic device. The tensile strength of the new cathode was 9.3 - fold higher than that of the conventional cathode, as measured with a tension meter. These results show that the new cathode is a cost-effective and mechanically-strong electrode with the performance of current production nearly equal to that of the conventional cathode. The new cathode is high in physical strength, and therefore, could tolerate the inner pressure of scaled-up MFC reactors in practical applications.
Keywords: microbial fuel cells, resource recovery, wastewater treatment, cathode, stainless steel
- Research Paper (Japanese)
Analysis of Hot-pressing Conditions in Adhesion of a Cost-effective Proton-exchange Membrane to a Cathode for the Application to Single-chambered Microbial Fuel Cells
- Mami OHWADA, Shiho ASAKAWA, Atsuo IKEGUCHI, Takahiro YAMASHITA and Hiroshi YOKOYAMA
- Microbial fuel cells (MFCs) are prospective bioreactors that simultaneously generate electricity and decompose organic matters in wastewater. In single-chambered MFCs with a proton–exchange membrane, the cathode is fused to the membrane by hot pressing, forming a membrane-electrode assembly (MEA). Nafion membrane is commonly used in the MFCs. However, the membrane is expensive, and thus development of MEAs made of low-cost materials is required. Selemion HSF membrane is an inexpensive alternative for nafion. Selemion HSF has been applied to two-chambered MFCs but not to single-chambered MFCs, since a preparation method of the MEA containing Selemion HSF has not been analyzed. In the present study, the hot-pressing conditions for the fusion of the Selemion membrane to a carbon-cloth cathode were analyzed, and the electrochemical performances of the Selemion-HSF MEA were compared to the conventional (Nafion) MEA. We revealed that the condition in the hot-pressing to prepare the Selemion-HSF MEA was a pressure of 780 kPa, temperature of 50 ℃, and pressing time of 40 min. MFCs equipped with the Selemion-HSF MEA displayed the maximum power density of 230 mW/m2 that was 1.9 - fold higher than that of MFCs equipped with the Nafion MEA. The internal resistance of the MFCs with Selemion HSF (106 to 112 Ω) was approximately half of that of the MFCs with Nafion. The current production of Selemion-HSF MEAs was 1.8 - fold higher than that of Nafion MEAs in a potentiostatic test. The removal percentage of chemical oxygen demand in the MFCs with Selemion-HSF MEA (84 to 87 %) was also higher than that of the MFCs with Nafion MEA (61 to 80 %). These results demonstrated that Selemion-HSF MEA is comparable to Nafion MEA in current production and removal of organic matters in the MFCs.
Keywords: microbial fuel cells, hot pressing, cathode, membrane-electrode assembly
- Technical Paper (Japanese)
Development of a System of Acid Coagulation Treatment of Waste Milk
- Yoichiro KOJIMA, Koichi MUROI, Keiichi NAGATAKI, Masatsugu OKAMOTO, Kiyomi KOSHII, Koichi AMAHA and Kazuhiro MATOBA
- This paper describes a treatment method for waste milk from dairy farming, using a coagulation reaction by acid addition to milk warmed to 45 ℃. In this study, a pilot-scale treatment unit was developed and used to investigate treatment performance (experiment 1), and the composting characteristics of mixtures of cowshed litter and separated coagulum were verified (experiment 2). In experiment 1, 16.8 % of raw milk was separated as a coagulum. More than 95 % of the coagulum was recovered by 5 - mm sieve. More than 50 % of chemical or biochemical oxygen demand of raw milk were removed from the supernatant by the coagulation treatment, due to the removal of more than 70 % of the milk fat and protein. In experiment 2, the temperature of composting material remained high, and the organic matter decomposed more with addition of milk coagulum than without it. Mixing milk coagulum in composting material had no negative effect on the composting process, and composting satisfactorily degraded the milk coagulum.
Keywords: waste milk, acid coagulation, the burden of wastewater treatment, composting
Vol.48 No.2 (June, 2017)
- Research Paper (Japanese)
Estimation of Body Surface Temperature Change of Swine Using Thermography by Machine Learning Approach
- Misaki MITO, Takuji KAWAGISHI, Koichi MIZUTANI, Keiichi ZEMPO, Naoto WAKATSUKI and Yoshifumi KUBOTA
- It is a big loss if overlooks swine estrus in breeding work in swine farm. Whether breeding swine are in estrus is a large work load for workers since it is needed to observe carefully many swine based on their experience in breeding work in swine farm. Previous research has shown that whether breeding swine are in estrus can be checked by measuring vulvar surface temperature change using thermography as a quantitative method. However, it was reported that temperature is easy to be changed by influence of external environment such as ambient temperature of swine. In this paper, we extract 5 external environment factors; gluteal surface temperature of swine using thermography, the temperature inside and outside swine farm. And we estimate vulvar temperature eliminated the influence of their factors. We performed 3 regression analysis by machine learning method, and evaluated the combination their factors and method for estimating. As a result, we could estimate vulvar temperature whose error is less, than 1.4 ℃ using gluteal temperature in swine, the temperature inside and around swine farm as external environment factors as explanatory variables. And we found this method can estimate temperature change by estrus correctly.
Keywords: swine, thermography, estrus estimation, machine learning, linear regression, support vector machine, neural network
- Note (Japanese)
Field Survey of Greenhouses Damaged by the 2016 Kumamoto Earthquake
- Hideki MORIYAMA, Limi OKUSHIMA, Masahisa ISHII and Ryota TSUCHIYA
- In April 2016, over a hundred greenhouses and numbers of bench systems in an area around the Kumamoto region were damaged by the Kumamoto Earthquake, which was a crustal earthquake. We surveyed a venlo-type greenhouse, four steel frame greenhouses, two reinforced pipe-framed greenhouses and bench systems inside those greenhouses damaged by the earthquake in Kumamoto prefecture. For the greenhouse structure, a seismic force and a ground fissure caused a leaning of columns and an unequal displacement of foundations. For the case of a heavy snow fall in 2014, rafters were bent and the roofs of the greenhouses were collapsed by the snow load which exceeded a design load. In the Kumamoto case, remarkable deformations were exclusively shown around the structure under the eave. There were few deformation around the roof structure above the eave. However, the liquefaction of the ground led to a harmful deformation of the valley gutters and ridge pipes and compelled farmers to cease horticulture. The structure of bench systems without bracing and firm connections are weaker and were observed to be more susceptible to damage from the seismic forces than greenhouses structures.
Keywords: Kumamoto Earthquake, disaster, greenhouse, bench system, leaning of columns, unequal displacement of foundations, seismic force, ground fissure, liquefaction
- Note (Japanese)
Rapeseed Purification Method and Improvement of Oil Fuel Quality
- Genta KANAI, Yukinori SHIBUYA and Hisashi KOWATA
- A belt-type soybean-sorter method and a motor vibrated screen method were examined for rapeseed grain purification. Activated clay was examined to improve low-quality rapeseed oil for utilization as diesel fuel.
- Bulk grain purification methods incorporating a belt-type soybean-sorter were examined to assess effects on oil quality for use in diesel fuel. Based on a rapeseed oil fuel standard, DIN51605, oil from grain classified as low quality was found to have lower fuel quality than oil from high-quality grain in terms of excess sulfur contents, acid values, oxidation stability, phosphorus contents, and calcium and magnesium contents. Low-quality grain contains many more sprouted and damaged grains, which are considered to result from broken skin of the grains and sprouting grains.
- Application of activated clay was examined to improve the oil fuel quality. Stirring the low-quality oil with activated clay of 10% weight of the oil improved the oil quality, reducing the total metal constituent from 441 ppm to 15 ppm.
- Grain purification tests demonstrated that a double screen, when vibrated using a motor, has lower capacity and overall separation efficiency than a double screen vibrated using compressed air. The motor-vibrated screen had more holes plugged by grains and admixtures than the other. The different directions of the vibration and stronger vibration might be useful to reduce screen plugging and to improve the capacity and overall separation efficiency.
Keywords: rapeseed, purification, SVO, activated clay, separator
Vol.48 No.3 (September, 2017)
- Research Paper (English)
Detection of Whitefly Bodies Using Image Processing in Greenhouse Environment
- Hayato UDO, Hiroki NAKABAYASHI, Koichi MIZUTANI, Tadashi EBIHARA, Naoto WAKATSUKI, Hiroyuki UGA and Kenji KUBOTA
- The purpose of this study is to investigate possibility of early detection of whitefly presence in greenhouse environment using image processing. Whiteflies are very small agricultural pests that carry serious viral plant diseases such as Tomato yellow leaf curl virus. One of the problems in whitefly control is that farmers cannot notice the presence of whiteflies in greenhouses until they increase their population. However, if it is possible to develop a system that monitors presence of whiteflies in greenhouse for long period of time, farmers can react and take measures much quickly. To achieve this, a system that monitors presence of whitefly in the greenhouse is necessary. In this paper, whitefly monitoring system composed of camera and image processing algorithm is proposed. Image processing techniques such as filtering, thresholding, and template matching were used to construct whitefly detection algorithm. Accuracy of the image processing method was examined. The detection system correctly detected 132 whitefly bodies out of 148 actual whiteflies in images, and rate of correct detection was 89.19 %. Also, out of 100 total sample frames, only two of them was incorrect detection and rate of incorrect detection was 2 %. The result clearly showed that detection of whiteflies was feasible with the proposed image processing method.
Keywords: sensing, machine vision, whitefly, monitoring
- Research Paper (Japanese)
Study on Plant Cultivation by Using Polyitaconic Acid-Polyvinyl Alcohol IPN Hydrogel
- Yu KOBAYASHI, Erika TAGUCHI, Michinori KARIKOMI and Takao KIMURA
- For use as a water reserving material or a plant culture medium, interpenetrating polymer network (IPN) hydrogel was prepared by combination of chemical crosslinking of polyitaconic acid with amidic type crosslinker and physical crosslinking of polyvinyl alcohol (PVA) based on hydrogen bonding. The effect of IPN hydrogel on the culture of a plant such as white radish sprouts or western turf was investigated by two direct seeding methods. Under the mixture of a soil (black soil or IWASE sand) and IPN hydrogel, the water retentivity of soils increased with the addition of more IPN hydrogel, and it was possible to culture plants over a longer time period. Under only IPN hydrogel as a culture medium, cation species included into IPN hydrogel affected plants growth and preferable growth of plants was observed in cultivation on the IPN hydrogel containing calcium ions as counter cation of the carboxylate anion.
Keywords: interpenetrating network (IPN) hydrogel, polyitaconic acid, polyvinyl alcohol (PVA)，water reserving material, soil, culture medium, white radish sprouts, western turf, calcium ion, plant cultivation
- Research Paper (Japanese)
The Trial Production and Evaluation of Biodegradable Mulch Film Composited with the Calcium Compound Fine Powder
- Haiyan HE, Rika SUZUKI, Michinori KARIKOMI, Takao KIMURA and Shigeaki MARUO
- Films were prepared by thermal kneading of a plastic matrix with a calcium compound fine powder derived from scallop shells or dolomite, followed by hot-press molding. The commercial biodegradable aliphatic polyester "Terramac TP-4071" that the main component is the blend of poly (L-lactic acid) and polybutylene succinate adipate was selected as a plastic matrix. The resulting films were investigated by a hydrolysis test and soil burial test for 90 d. The biodegradability of these films was examined by the time-course of weight loss, total organic carbon content, and the surface morphology, observed by SEM. In addition, it revealed a difference of the addition effect of the different modifiers. As a result, no matter which kind of the modifiers was added, it contributed to accelerate the speed of degradation of commercial biodegradable aliphatic polyesters and to suppress the acidification of soil used as the medium. However, due to the difference of the main component and the particle size of the modifiers, the degradation rate of the composite film was also found slightly difference.
Keywords: biodegradable aliphatic polyester, scallop shells, dolomite, pulverization, calcination, composite mulching film, hydrolysis test, soil burial test
- Note (Japanese)
Development and Application of Self-building Bamboo Structure for a Greenhouse - Case study on "Kumano Bamboo Greenhouses" in Kumano city, Mie Prefecture -
- Shingo NAGANO, Hirohide KOBAYASHI and Kouji TANI
- The objective of this study was to develop a self-bulidable greenhouse using bamboo to decrease cost for material and building work. Small-scale experimental Bamboo Greenhouses (BGHs) were built in Ikusei-cho, Kumano city, Mie Prefecture. Materials costs for both BGH No. 1, resembling an even-span greenhouse, and BGH No. 2, resembling an Quonset style greenhouse, were approximately 160,000 yen/a. This is approximately half that of a steel-pipe house. BGH No. 1 and BGH No. 2 could be built in 364 and 267 hours, respectively. The calculation of structural strength is difficult because of the variability of dryness and degradation of bamboo materials. However, critical damages have not been observed in either BGHs during the 47 months post-construction. As for the ability for heat retention, the average daily temperature inside of the BGH was 2.5 ℃ higher than the ambient temperature in winter.
- From these results, it is found that the costs of materials in BGHs were lower than that of steel-pipe house, and that BGHs can be self-built at a small-scale, irregular-shaped farmland. Continuous observations of bamboo strength will be conducted to determine the number of durable years, and a simpler method for assembly of the bamboo structure may be developed.
- Moreover, cutting bamboo for the maintenance of abandoned bamboo groves will help to prevent animal damage and to conserve the traditional landscape of farming and mountain villages.
Keywords: bamboo, small scale greenhouse, self-buildable, low-cost
Vol.48 No.4 (December, 2017)
- Research Paper (English)
Binary Power Generation Using Composting Fermentation Heat as Heat Source
- Yoichiro KOJIMA, Yuichi IITAKA, Yohei NISHI, Masaru NAKANISHI, Koichi AMAHA, Yoshiyuki ABE and Satoshi ENDO
- This paper describes binary power generation using fermentation heat as the high heat source. This heat, which is generated from the composting of organic matter, can be recovered using a Suction-type Aeration Composting System (SACS), a composting system that aerates composting material by sucking in air from the bottom of the material. The SACS facility was installed in a farm with 100 head of milking cows, and was used to verify the characteristics of using fermentation heat as the high heat source for binary power generation. The 60 ℃ exhaust gas from the facility was used as the high heat source for the power generation experiment. As a result, the layout that heated the water before and after the power generator resulted in the highest generation efficiency, and the power generated by using fermentation heat of about 216 MJ/hour (60 kW equivalent) was more than 700 W at maximum. Although power generation was interrupted by temperature decreases caused by turning over of the compost, it was maintained for approximately 60 h over in a three-day turning over cycle.
Keywords: power generation, composting fermentation heat, dairy cow manure, energy recovery
- Research Paper (Japanese)
Surveying Configuration of Pipe-framed Greenhouses on Hilly and Mountainous Areas in Nara Prefecture and Appropriate Setting of Tie-bar
- Satoshi KAMIKAWA and Hirokazu UMEMOTO
- With respect to the numerous configurations of pipe-framed greenhouse employed at farms in Japan, greater clarity on pipe-frame intensity is required. Therefore, we conducted studies on several pipe-farms at farms and analyzed stress. We also identified the appropriate installation position of tie-bar, which is one of the measures of damage by snow. The maximum stress on the pipe-frame was distributed as follows: grounded part by 1.2 m eave heights, eave part by 1.5 m, and 1.8 m eave heights. By installing the tie-bar at the position of f/8 (on pipe-frame), the maximum stress on the pipe-frame was minimized. When we conducted the load carrying test, wherein the tie-bar was installed at the position of f/8 (on pipe-frame), the collapse load was increased to approximately 2.3 times than that in the absence of a tie-bar and approximately 1.6 times than when the tie-bar is installed at the position of f/4 (on pipe-frame). As we studied loads applied on pipe-frames, it evaluated with promising T-band that has sufficiently large drawing tensions.
Keywords: pipe-framed greenhouse, pipe-frame, difference in structure, snow load, analysis of stress, tie-bar, installation position, fixture
- Research Paper (Japanese)
Study on Overseas Transfer of Fundamental Technology for Agricultural Machinery - A case study of business expansion overseas in Japanese local small and medium sized farm machinery and facility manufacturers -
- Yuichi OHASHI and Takaaki SATAKE
- In this study, we aimed to discuss some cases that the Japanese local small and medium sized enterprises (hereinafter “SMEs”) farm machinery/facility manufacturer (hereinafter “FMFM”) transferred their fundamental technology for agricultural machinery (hereinafter “FTAM”) for business expansions overseas, which in turn contributed to the economic revitalization of the local area. Firstly, we defined that the competiveness of SMEs-FMFM was links made through local business ties. To elaborate, labor-intensive cooperate activities such as “research and development”, “production and sales” and “employment“, derived from long standing connections of communities. Secondly, we conducted surveys to identify the key factors when operating overseas: decision-making, planning, and succeeding in the field, etc. We found that the SEMs-FMFM owners had strong ideologies of contributing socially and economically to the field country by placing high priority on relationship rationality when making business decisions. Additionally, the key to success, especially in developing countries, was by selecting a mediator who fully comprehended the technology-oriented network of the field country. In other word, the most important factor of the overseas business expansion was creating and expanding social capital in the field country. We concluded that the most effective way of formulating social capital was by relocating to on-site production as well as transferring the FTAM to the field employees. On the other hand, local businesses could convert from labor-intensive to knowledge-intensive cooperate activity: innovative research and development on production, strategic planning on a global scale etc. The findings suggested that the SMEs-FMFM overseas expansion not only led to the structural transformation of the Japanese agricultural machinery manufacturing industries, but also it has maintained and improved the FTAM. Moreover, by attracting a different demographic of prospective employee, it may lead to economic revitalization.
Keywords: farm machinery/facility manufacturer, fundamental technology for agricultural machinery (FTAM), business expansion overseas, social capital, relationship rationality, knowledge-intensive cooperate activity
