Archive - Abstract
Vol.47 No.1 (March, 2016)
- Research Paper (Japanese)
Collapse Processes of Pipe-Framed Greenhouses under Wind or Snow Loads
- Kazuya TAKAHASHI and Yasushi UEMATSU
- The present paper investigates the collapse process of pipe-framed greenhouses under wind or snow loading based on a non-linear finite element analysis in order to establish more reasonable wind and snow resistant designs. The analytical model is limited to a two dimensional problem.
- Regarding the wind loading, fluid-structure interaction (FSI) is considered, because the deformation under wind loading may affect the wind pressure distribution significantly. That is, the wind pressure distribution on the deformed structure is computed by Computational Fluid Dynamics (CFD), and then the result is used for the structural analysis at the next step. Focus is on the time-averaged deformation and wind pressure. The results indicate that the FSI effect is fairly small up to the allowable stress or deformation used in the current design standards. However, the FSI affects the collapse load and mode, significantly.
- Regarding the snow loading, not only even but also uneven distribution of snow accumulation are considered, because wind affects the snow accumulation significantly. The results indicate that the uneven load gives lower collapse load than the even load. It is found that the safety margin up to collapse beyond the allowable stress or deformation is rather small.
- The analytical results on collapse mode are consistent with the findings of damage investigations both for the wind and snow loadings.
Keywords: pipe-framed greenhouse, collapse process, closed structure, wind load, snow load, elastic-plastic analysis, fluid-structure interaction
- Technical Paper (Japanese)
Development of Automatic Welsh Onion Trimmer (Part 1) - Development of automatic devices for cutting root and peeling –
- Osamu FUJIOKA, Sadao OMORI, Hiroshi MATSUMOTO and Tomoaki KOGURE
- In welsh onion production, preparation time before shipment occupies about one third of total working hours. Therefore, we developed an automatic root cutting and peeling mechanism to save labor and implemented these mechanism into a prototype.
- As a result of field test using the prototype, the work efficiency was about 500 pieces per hour. As for the rate of precise root cutting was about 94 %, the rate of precise peeling was about 91 % and the rate of shippable pieces were about 96 %. The work efficiency of the prototype was about 1.5 times compare to an expert worker, precise workability was about equal. The prototype could reduce the noise of peeling device to 87 dB(A) from about 100 dB(A). We confirmed that had a soundproofing effect than normally used peeler.
- The joint development company has started marketing of automatic welsh onion trimmer on the basis of the prototype in 2002.
Keywords: welsh onion, root cutting, transmission optical sensor, peeling, compressed air, automatic device
- Technical Paper (Japanese)
Development of Automatic Welsh Onion Trimmer (Part 2) - Development of higher efficiency automatic trimmer for welsh onion and testing it on farmers field -
- Osamu FUJIOKA, Sadao OMORI, Hiroshi MATSUMOTO and Tomoaki KOGURE
- For getting higher performance than first prototype of automatic welsh onion trimmer, we made the second prototype which can trim two piece of welsh onion at the same time.
- As a result of field test at Akita and Oita Prefecture used the second prototype, the working efficiency was about 900-1200 pieces per hour. As for the rate of cutting root precisely was about 91-95 %, the rate of peeling precisely was about 87 % and the rate of shippable pieces were about 96-97 %. In one-man operation, the work efficiency was about 820 pieces per hour, and it became about 2.5 times than an expert worker. Therefore, we understood that the work efficiency improvement of the second prototype depends on the skill of supply work. The second prototype also could reduce the noise of peeling device to 88 dB(A) as equal as the first one. We confirmed that had a soundproofing effect than normally used peeler.
- The joint development company has started marketing of automatic welsh onion trimmer on the basis of the prototype in 2002.
Keywords: welsh onion, root cutting, peeling, automatic device, higher efficiency
- Technical Paper (Japanese)
Evaluation of the Performance of a Space-Saving Recirculation Dryer for Grain Drying, Processing, Storage Facilities
- Toru HIJIKATA, Hiroshi NAKATANI, Masakazu MATSUDA and Takaaki SATAKE
- A new space-saving model circulation dryer has been introduced for the operation of grain drying, processing, and storage facilities. This dryer permits a reduction in the size and overall height size of the structure, including the bucket elevator, by 20 %, while maintaining system capacity and function.
- As a result, owners and operators can expect a cost reduction for replacing old systems in existing facilities and for the construction of new facilities. Furthermore, the improvement of the dryer can be expected to reduce the damage of the grain, improving overall grain quality.
- Because of its important function in the operation of grain storage facilities, we examined the basic performance of the new space-saving circulation dryer in actual use at half- and full-capacity operation and obtained the following results, confirming design expectations.
- The processing capacity was 32 t/h, and the drying rate was almost 0.6 %/h, confirming the prescribed operation rates.
- The increase in the percentage of absolutely cracked grain before and after drying was not seen, and there was no degradation in the quality of the grain.
- The energy input requirement for the removal of water was between 4.7 and 5.5 MJ/kg, which is low when compared with the energy requirement reported for older systems, which was 5.7 MJ/kg.
Keywords: grain related facilities, recirculation dryer, drying rate, cracked rice, energy requirement for reducing moisture from raw grains
Vol.47 No.2 (June, 2016)
- Technical Paper (Japanese)
Evaluation of the Performance of an Original Equipment Manufacturing Far-infrared Radiation Dryer for Cooperative Grain Drying Processing Facilities
- Toru HIJIKATA, Hiroshi NAKATANI, Masakazu MATSUDA and Takaaki SATAKE
- A new original equipment manufacturing (OEM) model dryer has been introduced for the operation of cooperative grain drying, processing, and storage facilities. Far-infrared rays are used as the heat source of this dryer.
- The use of far-infrared rays leads to a reduction in fuel consumption, and hence, the overall costs associated with the OEM product. As such, owners and operators will benefit from the reduced costs of replacing old systems in existing facilities and the construction of new facilities.
- Owing to its important function in the operation of grain storage facilities, we examined the basic performance of the new OEM far-infrared radiation dryer in actual use at half- and full-capacity operations. The results were consistent with design expectations, and are listed below.
- The processing capacity and drying rate were 17 t/h and 0.6%/h, respectively, at full-capacity operation, thereby confirming the prescribed operation rates.
- Furthermore, according to the standard drying methods, the drying temperature of the grains is < 35 ℃.
- Further, there was negligible increase in the percentage of cracked grains after drying, and there was no decrease in the quality of the grain.
- Moreover, the energy input (4.2-4.8 MJ/kg-H2O) requirement for the removal of water, is significantly lower than that (5.7 MJ/kg-H2O) required for older systems.
- These results confirm that the use of this dryer will lead to both reductions in energy consumption and operating costs.
Keywords: far infrared radiation dryer, drying rate, cooperative grain drying processing facilities, input energy for 1 kg of removal water, rate of cracked grain
- Technical Paper (Japanese)
Combustion Characteristics of Wood Pellets and Giant Miscanthus Pellets in a Wood Boiler
- Genta KANAI and Hisashi KOWATA
- To assess the use of pellet fuels in wood boilers, we examined wood pellet and Giant Miscanthus (Miscanthus giganteus) pellet combustion in a wood boiler connected with a grain dryer. The lighting position, fuel adjuster board (FAB), and combustion control sheet (CCS) were examined for combustion process improvement.
- When pellets were burned in the boiler, fires were lit on the chimney side of the kiln, where the deep side of the kiln exhibited longer combustion duration time than at the air inlet side of the kiln.
- Unburned pellets were found accumulated in the kiln corner because of the poor air supply. The FAB was introduced to set pellets on the air inlet pipe, not in the kiln corner. The FAB improved the combustion duration time, the heat output, and the efficiency from fuel to the output.
- Pellets showed faster combustion than firewood because of their larger surface area. The CCS was intended to delay the pellet combustion by putting a heat insulating sheet on the fuel in the kiln to reduce exposure to air. Consequently, CCS had no effect on prolonging combustion duration, but it decreased the smoking time.
- Burning Giant Miscanthus pellets in the boiler was found to have longer smoking time than burning wood pellets. However, no major difficulty was observed compared to wood pellet combustion.
Keywords: wood boiler, pellet, grain dryer, solid fuel, Giant Miscanthus, heat efficiency
- Technical Paper (Japanese)
Study on Actual Performance of a Grain-Cooling System Introduced in Silos used in Cooperative Grain Drying and Processing Facilities
- Toru HIJIKATA, Souichi Wada, Hiroshi NAKATANI, Masakazu MATSUDA and Takaaki SATAKE
- The performance of a grain-cooling system for reducing the heat to which wheat and rice grains stored in silos are subjected through the exterior surface of the silo wall was evaluated. This system can be used when the grain temperature and the outside temperature are both high at the start of the storage process. Grain-cooling systems have seen numerous advances. However, few studies have investigated the effects of the operating conditions. We examined the basic performance of the grain-cooling system using an actual silo and obtained the following results. The cooling air introduced into the test silo used cooled the silo (storage capacity of 300 t) to 16-18 ℃ in 17-44 h, with the humidity being approximately 75 %. However, when examining the performance of the cooling system, we overlooked the process for cooling the dryer and stored 250 t of paddy grains in the test silo. The temperature of the stored paddy grains was initially approximately 36 ℃ but decreased to 20 ℃ in approximately 33 h. The results of these examinations confirm the silo-cooling effect of the system. However, it should be noted that the cooling time as well as the condensation of dew on the inner wall of the silo should also be taken into consideration during performance evaluation.
Keywords: country elevator, cooperative grain drying processing facilities, grain temperature, silo storage, grain cooling system
Vol.47 No.3 (September, 2016)
- Research Paper (Japanese)
Capacities for Heat Pump Combined Heating and Cooling Systems with Energy Storage for Greenhouses in Japan
- Limi OKUSHIMA, David R. MEARS, Sadanori SASE, Tadashi TAKAKURA, Hideki MORIYAMA, Shinsuke FURUNO and Masahisa ISHII
- Water to water heat pumps for heating and cooling with a geothermal source and two storages, (one for cool and one for warm), have been compared to dedicated systems with a single storage for either heating or cooling. Four locations have been considered for one common, relatively energy efficient greenhouse type. These systems have very similar capacity for either heating or cooling as a single storage system for either heating or cooling alone. Adding a second storage enables the same heat pump and heat exchanger system to provide similar levels of heating and cooling as separate systems would. Also a system with only two larger storages but no geothermal source can meet some of the cooling needs and most or even all of the heating need if the cooling set points are low enough. All of the systems increase the number of hours the greenhouse can be kept closed without ventilation.
Keywords: heat pump, geothermal source, greenhouses, heating demands, cooling demands, thermal storage, heat exchanger
- Research Paper (English)
Developments of Compost Deodorization System for Composting Cattle Manure - Stabilization of ammonium nitrogen in compost by adding finished compost and activated sludge -
- Akihiro TANAKA
- Odors from fermentation reactors are conducted into deodorization reactors which install the stabilized cattle manure compost in the compost deodorization system for deodorizing the odor during composting cattle manure. The stabilized cattle manure compost in the deodorization reactors has the ability to adsorb the odor from composting, and the main substance of the odor from composting is ammonia. The adsorbent is required to replace when the compost in the deodorization reactors is saturated by ammonia. It is desired to convert the adsorbed ammonia by compost into odor-less material to sustain the deodorization effect for a long period of time and to avoid the volatilization of ammonia. The present study evaluated the stabilization of ammonia absorbed by the approximately one-year-old cattle manure compost and identifies the effects of additives such as activated sludge and finished compost on nitrification and organification of ammonia in compost. For that purpose, the effect of two kinds of additives viz. activated sludge (at 5 %, 10 % and 20 % based on weight) and finished cattle manure compost (at 10 %, 20 % and 30 % based on weight) on the stabilization of ammonium in the compost was compared. The large amounts of ammonium nitrogen were decreased within 3 d and the reduction rates were ranged from 81.4 % to 87.5 %. However, there were no significant differences among the treatments as well with control. The activated sludge additive had the highest oxidation rate among the treatments, and it had about 3.0 times greater rate than the control. The sum of the nitrite nitrogen and nitrate nitrogen contents for the activate sludge additive treatment and finished compost additive treatments were uniformly increased up to 14 ds (114.7 % to 225.3 %), regardless of 134.8 % up to 49 d for the control, since the treatments can accelerate nitrification. After 21 or 28 d, the nitrite and nitrate nitrogen were changed to organic nitrogen by the finished compost additive treatments, indicating less susceptibility of underground water pollution. In present study, 10 % of ingredients in the finished cattle manure compost seemed to have sufficient effects for the conversion of adsorbed ammonia to organic nitrogen, and was evaluated as the suitable treatment to produce the adsorbent compost for the compost deodorization system.
Keywords: deodorization, compost, ammonia, nitrification, organification
Vol.47 No.4 (December, 2016)
- Research Paper (Japanese)
Development of a New Type of Steel Greenhouse with High Wind-Resistance Utilizing the Drag Reduction by Wing-Like Cross Section
- Namsoek KIM and Yasushi UEMATSU
- The purpose of the present study is to develop a new type of steel greenhouse with wing-like cross section, which has high wind resistance despite a long span. The concept of the development is based on a fact that the characteristics of wind loads on a structure strongly depend on the structure's shape.
- First, a computational fluid dynamics (CFD) model suitable for the present study was established by comparing the CFD results with the experimental ones reported by Uematsu et al. (2004) for a steel greenhouse with wing-like cross section. Then, the effects of three parameters describing the wing-like cross section on the drag coefficient were investigated by a series of CFD analyses. Based on the results, together with a consideration for the workability inside the greenhouse, the most suitable cross section was proposed. Note that a two-dimensional model was used in this analysis. Finally, a wind tunnel experiment was carried out using a three-dimensional greenhouse model with the proposed cross section. The span and length of the model were assumed 20 m and 60 m, respectively. The experimental result on the wind pressure distribution was found to be in good agreement with the CFD result. Furthermore, the distribution of wind pressure coefficients on the model was investigated on the basis of the wind tunnel experiment.
Keywords: steel greenhouse, wind tunnel experiment, computational fluid dynamics, wing-like cross section, wind load reduction, drag coefficient
- Research Paper (Japanese)
Effect of Air Velocity and High Relative Humidity on Growth and Water Use Efficiency of Cucumber in a Closed Greenhouse Environmental Control System
- Hiroki UMEDA, Mami SUZUKI, Yasunaga IWASAKI, Seiji MATSUO, Toshiaki SUGIHARA and Sakae SHIBUSAWA
- To develop an effective method for improving water use efficiency in a closed greenhouse environmental control system, we investigated the effects of air velocity on the growth and water use efficiency of cucumber seedlings under high relative humidity. Seedlings in closed plastic chambers were exposed to one of three air velocities in closed plastic chambers: 0 m s-1, 0.24 m s-1, or 0.66 m s-1. Dry weights of the cucumber seedlings in the 0.24 m s-1 and in 0.66 m s-1 air velocity treatments were higher than that of seedlings in the 0 m s-1 treatment. Seedlings subjected to an air velocity of 0.24 m s-1 was the highest among the treatments, at an average of RH 92.1 %. In addition, seedlings exposed to 0.24 m s-1 and 0.66 m s-1 winds had higher water use efficiencies than seedlings in the 0 m s-1 treatment.
- These results indicate that in a closed greenhouse environmental control system, controlling air velocity at high relative humidity makes it possible to increase the photosynthetic rate of seedlings while minimizing increases in water uptake.
Keywords: closed greenhouse environmental control system, air velocity control, relative humidity, photosynthesis rate, water use efficiency
- Note (Japanese)
Search of Optimum Transportation Route for Agricultural Products using GA
- Takaaki SATAKE, Tohru HIJIKATA, Michikazu ICHIKAWA, Kazuhiro ODAKA and Osamu SAKATA
- The genetic algorithm (GA) is a stochastic searching, learning and optimizing method for computer simulation. Utilizing GA, we have developed a basic simulator to find an optimum transportation route which can reduce transport cost of agricultural products. The simulator is coded by C language based on ANSI. It can find an optimum transportation route, given several parameters which are traffic volume, geographical information of passing through points, performance of delivery vehicle, etc.
- Two pairs of simulation experiments were designed and carried out: 1) traveling with empty load and delivery, 2) picking up cargo and delivering. As a result, the average fuel cost of the transportation route found by GA is considerably lower than the one obtained by random searching (RS) method in each simulation. On the other hand, the searched optimum transportation routes did not correspond between traveling picking up agricultural products and delivering, under the condition that each cargo quantity was same.
- These results lead us to the conclusion that our simulator is useful for searching an optimum transportation route and that the big cost cut in transportation of agricultural products is realized by combining GA and concrete transportation data about target agricultural products.
Keywords: genetic algorithm, combinatorial optimization problem, optimum transportation route, traffic hindrance, fuel cost, delivery route, random search
