When a small size air-cooled Wankel rotary engine for general use is operated under about a half of maximum power output, irregular combustion phenomenon occurs. And when idling, a large cyclic variation due to complicated intermittent burning repeating firing and misfiring obstructs the smooth running of the engine. Consequently, an undesirable countermeasure such as raising of idling speed is required. Besides, there is another difficult problem that the exhaust gas temperature is very high compared with that of conventional piston engine. The causes of these troubles and their countermeasures are reported.

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The object of the present study is to design a subsoiler which introduces fluid into soil-bed layer to break soil. Laboratory tests using a movable soil-bin were conducted to determine the optimum tool shape to get maximum soil failure and to minimize the draft force. The nature of soil failure was also studied. As a result, the following points were clarified; the rate of the draft forces produced by a chisel and the standard of the subsoiler, the position of the nozzle port to introduce fluid and the method to prevent the leakage of fluid into the subsoiler path.
This study was conducted by a National Grant-in Aid for Scientific Research. The writer wishes to express his gratitude for making this work possible.

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This paper describes the design method of scoop surface of rotary tiller blades and model tests with designed blades and commonly used Japanese blades in order to improve backward throwing of soil clods on deep rotary tillage.
1) Up cutrotary tilling was superior for backward throwing of tilled soil clods.
2) In the case of any tilling condition, the design method studied in this paper proposed appropriate scoop surface for throwing the soil backward when throwing direction and its distance were given.
3) The blade designed by this method was superior for throwing of the soil clods. And the locus of thrown soil clods was agreed with the simulation result which calculated with the throwing model.
4) Tillage with the designed blade might give less tilling energy caused by repeat cutting of tilled soil than with commonly used Japanese blade.

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An edge-form of the C-shaped rotary blade (Japanese typed rotary blade) is a double-edged blade in general, while the European L-shaped rotary blade is of almost single-edged blade. According to theoretical analysis of the soil cutting mechanism of the lengthwise blade and tip blade portions, it was obtained that the single-edged blade was more reasonable than the double-edged one for the decreasing their tillage resistance.
The lengthwise blades of single and double edge and also the perfect blades in the market were used for the test, in order to compare the cultivating characteristics of their single and double-edged ones at the laboratory tests. The results were obtained that the tillage resistance of single-edged blade was from 10% to 30% smaller than that of double-edged one.

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Vibratory tillage tools are classified as either subsoilers or plows, according to the mechanism of soil cutting. Each can be divided into 4 types, according to the cutting directional angle β, such as back to forward motion, up and down motion, a mixed motion of back to forward and up and down is used when the cutting directional angle β is greater than 0°, and a mixed motion of back to forward and up to down is used when the cutting directional angle β is smaller than 0°.
The purpose of this study is to solve some problems of the vibratory soil cutting of subsoilers. In this report, by observing the behavior of instantaneous soil cutting force, the mechanism of draft force reduction on each 4 types were explained and some pertinent imformation regarding the optimal cutting directional angle β which is one of the most important parameters of vibrating subsoiler were obtained. At the same time, a new factor of draft force reduction on vibratory subsoiler was discovered.

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This study was done to compare numbers of spray droplets and their sizes resulting from the difference between wettable powder and emulsifiable concentrate, the difference between non-coated slide glasses and polyethelen coated paper on catching spray droplets, the difference between black-white film and colored one on photographing, and the difference between the distance from the nozzle in the green house low volume application.
The data obtained here were summarized as follows.
(1) There was a significant difference between numbers of spray droplets caught on non-coated slide glass and those on polyethelene-coated paper. The numbers of the former were about 30 droplets per 6×10⁴(μm)² more than that of the later.
(2) Maximum frequency diameter of droplet was 1μm, and the frequency distribution of 1μm in diameter was higher according as the slide glasses or papers were away from the nozzle, and became 50% at 34m from the nozzle. There was no significant difference between the catching materials of spray droplets, or between photographings.
(3) By analyzing coverage ratio statistically, the materials of catching spray droplets, the characteristic of agricultural chemicals and the distance from the nozzle were significant. Coverage ratio on non-coated slide glass was higher than that on polyethelene coated paper.
Coverage ratio of sprayed wettable powder was higher than that of emulsifiable concentrate. Coverage ratio at 25m apart from nozzle decreased remarkably.
(4) Mean diameters of droplets were d₁=2-3μm, d₂=4-6μm, d₃=6-10μm, d₆=20-36μm respectively.
There was a significant difference only between wettable powder and emulsifiable concentrate spraying, but no significant difference between the catching materials or between photographings.
(5) The coefficient on uniformity of droplet size was 10-30% within 10m from the nozzle and 30-50% beyond 20m.

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A fresh market cabbage harvester was constructed on the previous experimental bases. The main components of the harvesting unit were a pair of screw-augers, a knife fixed in the direction of about 45 deg to the screw-augers and an overhead belt-conveyor. As the result of field tests in 1980/81, the percentage of “well harvested” heads except “shallow cut” and “deep cut” ones was estimated as about 50-60% under the adjustment condition to lead the rate of “deep cut” heads less than 5%. And also, the following plant and field conditions were found as factors influencing cutting height; length from the ground surface to the butt of heads, number of wrapper leaves before harvesting, vertical force required to remove cabbages from the ground, and head height under the condition that the overhead belt-conveyor pushed strongly heads down on the screw-augers whereas head diameter under the condition that it pushed weakly heads. It was, therefore, considered that it necessitated essentially developing the automatic control technique of cutting height to improve the above stated harvesting accuracy.

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Since Okinawa was returned to Japan in 1972, the agriculture in Okinawa has been developing. In recent years, transportation of fruits, vegetables and cut flowers to the mainland Japan from Okinawa has been rapidly increasing.
Most of them are transported by airfreight. On other hand freight traffics are larger than the capacity of scheduled airfreight from Naha to the mainland Japan.
The refrigerated marine container transportation system is contemplated to accept the freight traffic of rapidly increasing horticultural products. It was very rare that the air transportation system of perishable horticultural products was replaced by refrigerated marine container system, there was little literature on the comparison of their quality changes.
Air and refrigerated marine container transportation tests of Sayaingen were carried out to compare with the environmental conditions and quality changes during their transportation.

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The supplied energy for grain dryer is finally converted into the energy of concentration of grain moisture, and stored in grain. This energy is released as heat of wetting when the moisture absorption occurs. In this study, the method of exergy evaluation for grain dryer in consideration of this energy of moisture concentration was proposed and the concrete examples were shown.
1. The exergy of the moist air and moist grain in consideration of moisture concentration difference from surrounding condition were expressed respectively in equations (3-9, 15). The calculated values were illustrated in Fig. 3-3-6.
2. Energy and exergy flow of actual heated air dryers of rice were illustrated in Fig. 3-7, 8. The conversion efficiency of fuel energy to moisture concentration energy for heated air dryers of rice was 2-4%. The conversion efficiency of fuel exergy to moisture concentration exergy was extremely low: about 0.5-1%. The exergy loss due to combustion in heated air producer and irreversible heat transfer to grain and irreversible removal and evaporation of grain moisture in drying chamber occupied the great part. The exergy loss due to heat quantity loss such as wall loss and exhaust loss was small quantity.
3. The changes of exergy of flow air and grain (Fig. 3-9, 10) and exergy flow (Fig. 3-11) in grain drying system with heat pump using atmospheric and exhaust heat as heat source were obtained.
4. The exergy efficiency of heated air producer of the heat pump using exhaust heat as heat source was 18%, and the conversion efficiency of exergy of heated air to grain moisture concentration exergy was 13%. Finally, the conversion efficiency of supplied exergy to grain moisture concentration exergy for this system was 2.3%, and this was 4 times of the exergy efficiency of ordinary heated air dryers of rice.

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The drying characteristics of two stages of falling-rate periods observed in grain drying have been assumed to depend on the presence of brown rice and husk, respectively.
In this paper, the water tanks model was developed based on the grain configuration to describe these drying characteristics for rough rice and barley drying.
Concretely speaking, the authors supposed that brown rice and husk were two water tanks combined with each other in series and that the tanks had each capacity and the connected pipes of each resistance. And then, this model was called as “Two-Tanks Model”.
From the comparison of mathematical model and experimental results for thin layer drying, the usefulness of this model was recognized.
Dynamic equilibrium moisture content and the effect of air temperature on drying constants were investigated.

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In order to investigate the adaptability and the utility of the multi-layer passing-type dryer for the pre-drying of naked barley, the drying characteristics tests with a miniature drying machine and the operational performance tests with a practical drying machine were made.
1. The drying characteristics tests with a miniature drying machine.
The processing efficiency and pearling aptitude with utilizing the miniture drying machine (Fig. 1) were investigated in different periods of harvest (in different moisture contents of grain) and forced air temperatures. Experiments were conducted under the constant condition of 0.3m³/s·100kg air flow rate and 3 layers.
1) Periods of harvest and properties of naked barley
This experiment was done in 1980, in which the ripeness of naked barley was delayed comparing with the common year, and the weather condition was unsettled in the periods of harvest (Fig. 2).
Therefore, the harvesting with head feeding combine had been necessalily practiced at the high moisture content of grain about 30-40% (Table 1).
2) Drying progress and the processing efficiency
The multi-layer passing-type dryer had been indicated high thermal efficiency in case of the high moist grain, and the exhaust air temperature of this dryer was nearly equal to the outside air temperature (Fig. 3). In case that the lower moist grain was piled, the moisture absorption had occurred in the top layer (Fig. 4).
The drying progress of the muhi-layer passing-type dryer was able to conjecture from the change of inlet and exhaust air condition (Fig. 5). The lower the moisture content of grain and the higher the forced air temperature, the shorter was the interval time of dumping (discharging), therefore the processing efficiency increased (Table 2). On the other hand, the drying rate of the grain piled in the top layer decreased and the moisture absorption remarkably appeared (Fig. 6).
3) Dignity and pearling aptitude
The grade of dignity and pearling aptitude was not so influenced by the period of harvest and forced air temperature. But, in the case of 75°C, the germination deteriorated in spite of the very short pre-drying time (Table 3).
2. The operational performance tests with a practical drying machine
The operational performance of the multi-layer passing-type dryer (Fig. 7) for pre-drying was investigated. From this experiment, it was comfirmed that the growth of blocking and the leavings of grain were nothing, and the pre-drying was efficiently achieved (Table 4, Fig. 8).
The total working hours of dumping and discharging was about 7.4 minutes (Table 5). For the high moist naked barley, it was estimated that the pre-drying capacity of a multi-layer passing-type dryer (4.0m² floor space) corresponded with 2-4 units of circulation type dryer of 2-2.5ton/unit.

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Experiments on a practical scale have been conducted to collect data for utilizing abundant and clean solar energy in order to save energy in rice drying.
A solar collector and a vinyl-house were used to collect solar energy in rice drying and the performances of both methods were compared.
In order for practical application of these methods, studied were such relationships between dying rate and quantity of solar radiation, and between daily average collector efficiency and both air flow rate and quantity of solar radiation as well as the method of estimating collector area and the efficiency of vinyl-house.

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In order to clear the behavior of compression stress and strain characteristic of rice husk, the stress relaxation test and the creep test were experimented using the plunger and cylinder type compression device. Some results are summarized as follows.
1) The relaxation modulus of rice husk had a linearity and the following equation was obtained in relation between the relaxation modulus and the time,
G(t)=a·logt+b
where, G(t) is the relaxation modulus, t is the time and a, b are constant values.
2) The larger the initial stress, the larger the value of relaxation spectrum and the shorter the relaxation time.
3) The creep compliance of rice husk had a linearity and the following equation was obtained in relation between the creep compliance and the time,
J(t)=c·logt+d
where, J(t) is the creep compliance, t is the time and c, d are constant values.
4) The smaller the initial compression stress, the larger the ratio of the increase of the compression stress and the value of retardation spectrum.
5) The creep strain and the residual strain had a tendency to increase with the increase of the number of repeated creep tests.
6) The result of the stress relaxation test and the result of the creep test were compared using the approximate equation. From this comparison, it may he conclude that these two results could convert together.

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In dairy farming, much hot water are used for washing, heating, milking and refrigeration.
Paying attention to the quality and quantity of heat demand in dairy farming, a solar energy system to supply hot water which consists of high temperature and low temperature system is devised. A border of temperature between two systems is considered about 70-80°C.
In this paper, characteristics of a concentrating collector manufactured by way of trial for high temperature system are reported. Finally, collection of heat till 130-140°C will be held by the concentrating collector, but this paper described the case in which temperature of collection of heat was limited below 100°C using water as heat transfer medium to compare with a flat plate collector on a market for low temperature system.
The main results were as follows:
1) The concentrating collector could collect about 1800kcal (7540kJ) per day and maximum temperature of water in a storage tank was about 80-90°C in summer, and about 1300kcal (5400kJ) and 60-70°C in winter. The flat plate collector could collect about 70-80% of the concentrating collector at the temperature 50-55°C in winter.
2) Introducing the concept of exergy, the concentrating collector could collect about 80kcal (330kJ) per day both in summer and winter, and this quantity is about two times as much as that of the flat plate collector.
3) Collector efficiency of the concentrating collector takes the value about 60% at the maximum, and decreases according to conditions of solar radiation, ambient temperature and collecting temperature.
4) Collector efficiency of the concentrating collector was calculated theoretically by classifying the heat flow in the cross section into conduction, convection and radiation, and compared with experimental results.
5) Converting heat flow mentioned above into exergy flow, exergy efficiency of the concentrating collector was calculated theoretically. Exergy efficiency was about 10% and some differences between collector and exergy efficiency were appeared clearly.

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