Performance tests of small diesel engine for farm use using rape-seed oil as fuel were carried out and the following results were obtained.
(1) In the case of rated-horsepower operation, the specific fuel consumption of rape-seed oil showed 10-16 percent larger than that of light oil. Since the heating values of rape-seed oill was smaller than that of. light oil, the brake thermal efficiency of rape-seed oil was equal to that of light oil.
(2) Exhaust gas temperature of rape-seed oil was 10-15°C lower than that of light oil in the continuous cruising test.
(3) The brake thermal efficiency of rape-seed oil was higher than that of light oil for the operation of overload rating and maximum power.
(4) Other performances (at starting, at no load performance of maximum and minimum engine speed) using rape-seed oil were almost equal to those of light oil.

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To study the gear strength of small powered tractors, we theoretically calculated the gear strength, and measured the transmissibility of tractors both in the field and in bench tests, and estimated the bending-fatigue-limit of gears by progressive stress tests. The results obtained were as follows:
1. Increasing the output-shaft-load, the drive power differences between every shaft of tractor were measured.
2. The abrasion of small powered tractor gears suddenly increased when running hour reached 300hr. Especially, the high abrasion was occured for the gears which number of teeth was few and rotational speed was fast.
3. The static and fatigue-bending-strength of the gears was nearly in proportion to the tensile strength of steel gears.
4. The repetitive number of bending-fatigue-limits of small powered tractor gears was estimated to be about 1-3×10⁶.
5. The fatigue coefficient of small powered tractor gears was 2.0-2.3.
6. The bending-fatigue-limit values, estimated by Prot and Henry methods, almost agreed with the results obtained by S-N curve. The bending-fatigue-limit of gears can easily be estimated by using only a few data of the progressive-stress-method.

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Bringing the leakage flow and loss torque of the pump and motor in the served hydraulic control circuit into focus, their basic equations were derived in this paper. Then, both theoretical and experimental analyses were done minutely about these two loss factors. These results may be summarized as follows:
As for the leakage flow, drawing up “a balance sheet of inflow and outflow” in the circuit, the overall leakage flow of the pump and motor were divided into external and internal leakage flow, respectively. Then, about each flow, the calculation method was described on the basis of the experimental results. Moreover, we pointed out the measuring points of the flow necessary for these calculations. Here, the pump external leakage flow generally contains drain flow of the servo system and surplus flow charged to the main circuit besides the actual external leakage flow. Therefore, under the assumption that the charging efficiency of the boost pump is known, its actual flow was found by subtracting the above mixed flow from the measured pump case drain flow. (See. Equ. 13). Consequently, it was evident that the ratio of external leakage flow of the served pump and motor to each overall leakage flow was relatively small. Then, the clearance brought about the leakage was calculated by using these flows. From these calculation results, each clearance increased along with pump set speed but decreased in inverse proprtion to the cubic root of working pressure. Therefore, it took a maximum value at the pressure of zero. From the facts described above, we may conclude that the thermal wedge theory is more applicable than the laminar one for the calculation of the external leakage flow. About the internal leakage flow, experimental values agreed well with the theoretical results in quality and quantity. This is based on the reasons why the displacement of the served motor is fixed and there is no relief groove in it. From these results, the following became evident: the served pump has such characteristics that internal leakage flow increases in proportion to Δp_p and n_p. On the other hand, the motor has characteristics proportional to n_p under the same pressure, because q_M is constant, but inversely to Δp_M under the same speed.
Loss torque of the pump and motor is generally composed of the following three factors: viscous friction torque proportional to speed, friction torque proportional to pressure and constant loss torque, namely skin friction torque. Here, derivation methods of basic equation were described briefly so as to aid the analysis of the experimental results. Moreover, the overall loss torque of the pump and motor was calculated respectively by an algebraic operation from an actual shaft torque and theoretical one. Then, the detail of each torque was obtained by using the performance coefficient found out experimentally. Consequently, it was recognized from the pump and motor alike that we had to consider a compression loss of the working fluid other than above loss factors in the middle and high pressure ranges. Especially, the compression loss of the pump was larger than that of the motor. The factors affecting it could be as follows; The pump displacement decreases inversely to the working pressure according to the control action. Thus, the fluid remained in the plunger is compressed strongly at the pump delivery stroke. Though the results calculated from the theoretical equation agreed qualitatively with the experimental results, we did not get to compare all variables precisely, especially for the more difficult measurements. However, if we make a reference to the existing reports, it was concluded that we were allowed to divide the overall loss torque into above four factors.

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Pattern processing control of a travelling chassis is reported. The chassis, constructed to develope a fully automated farming system, has the horizontal span of 2.8m and the height of 1.3m and is driven by the all four AC reversible brake motors, whose motion and direction are controlled by the computer operated relays.
Objective pattern, taken from the computer controlled ITV camera, is digitized in 64×64 picture elements and the objective region is determined with the brightness threshold and the area threshold by the on-line real time operation. Then, the center point of the extracted region is calculated at every repetitive cycle and simultaneousely, the center position is dot-represented on the graphic display. When the center point is found to enter into the middle third zone of the visual field in respect to the travelling direction, the stop relay of the chassis is activated.
Successful controllability with the object of vegetable is obtained. This pattern processing control method was expected to grow to a useful tool for the farm automation.

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The dynamic response of a tractor body and its seat to random input was examined by using the original tractor and the dynamic model. The dynamic model was the linear model of multiple input as Fig. 1. A comparison between the model and the actual tractor was made in respect to vertical acceleration of the tractor and its seat, and transfer function was examined.
1. The transient response of the tractor body and its seat to bump showed the peak of acceleration when each wheel began to go up or end to go down. Comparison between the simulated model and the actual tractor generally showed fairly good agreement, but the peak value in the model tended to be larger than the value in the actual tractor when travelling speed was small.
2. The dynamic motion of the tractor body and its seat to random surface such as farm road-ways and fields became severe with the increase of the power spectral density of roads and with the increase of travelling speed. Comparison between the model and the actual tractor to random input showed a fairly good agreement in low frequency. However in a certain frequency range (for example, about 3Hz in V=180cm/s), the resulting vertical acceleration of the model showed larger value than the actual tractor. This result mainly comes from the assumption that the model wheels always touch the road surface, in spite of the fact that the actual wheels sometimes don't touch in relation to the diameter of the wheel to the period of unevenness of the road surface, in a certain frequncy range.
3. The transfer function of the two-input system of the front and rear wheels showed the periodic peaks. The transfer function of the single input system corresponded to the curve tracing the periodic peaks. The periodic peaks appeared in the twoinput system were caused by the time lag between the front and rear wheel input. The interval of the peaks was equivalent to V/L, and became narrower in proportion to the reduced travelling speed.
As the tractor speed is generally slow, future studies to reduce the transmission of vibrations from the road can be fully examined by the single input system

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This paper presents a theoretical analysis of a crawler on an inclined ground.
The authors have already developed a mathematical model of turning motion of a crawler on a level ground, and this model has proved to be capable of simulating a experimental test.
In this study, the authors have developed the extended model of crawler maneuver on an inclined ground based on the model on a level ground. The model can be used in the studies of crawler behaviors, track-slippage, load-distribution and required tractive forces.

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Experiments on onion topper were conducted for different types of retarder to determine the effects on topping performance. The results obtained are summerized as follows;
1. Fixed type rertader
Two types of retarder, net covered and tined type, were used (Fig. 2). The net covered type retarder did not give satisfactory topping performance. The tined type retarder was a little mare effective than net covered type and miss-topped bulbs were reduced to 7.4% when the harvesting rate of bulbs was less than 2.6ton/hr.
2. Rotary retarder
Higher revolving speed of retarder resulted in higher topping performance. However, greater harvesting rate of bulbs resulted in more miss-topped bulbs. On the other hand the topping performance at different angle of screen slope was not evident. When the harvesting rate of bulbs was less than 5ton/hr and topper was set at 35-50rpm revolving speed of retarder and at the angle of screen slope of 1.5-3.0 degrees, miss topped bulbs were able to be reduced to 1.5%.
The topping performance at different harvesting term was investigated. In these experiments topping was done at the rate of 5ton/hr and topper was set at 48.7rpm revolving speed of retarder and at the angle of screen slope of 3 degrees. In the case of early harvesting term (September 12), the stripped and damaged bulbs were only 0.7%. However, miss-topped bulbs reached about 24% under non-curing tops condition (a moisture content of tops was 69.1% and a green tops ratio was 59.4%). In the case of latest harvesting term (October 2), miss-topped bulbs were decreased 4.0% and the stripped and damaged bulbs were 1.3% (a moisture content of tops was 28.6% and a green tops ratio was 0.0%).
Through these experiments it was found that this topper could be used in practice between mid-September and early-October.

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In order to investigate the effects of dropping practice in packinghouse lines on the quality of satsuma mandarin, simulated handling tests were conducted. To evaluate the effect of dropping practice, the changes of gas permeability through the peel and the fruit firmness (force-deformation ratio) during the shelf time for a week or so after dropping treatment were investigated. In conjunction with them, the concentrations of O₂ and CO₂ of the internal atomosphere of the fruit, the concentration of dissolved O₂ in the flesh and the change of dehydro-ascorbic acid (DHA) in the flesh were discussed in detail. Results were obtained as follows.
1. Dropping practice made the gas permeability through the peel increased. It would be due to the mechanical injury by dropping practice which occured in the peel tissues.
2. The firmness of dropped fruit decreased evidently with the increase of repetition of drops.
3. In case of non-dropped fruit, the concentration of O₂ of the internal atomosphere of the fruit was about 19% at the time of harvest and did not change for 20 hours, however, CO₂ decreased gradually from 2.9% to 2.1%. On the other hand, in case of dropped one, O₂ decreased to 17.7% just after dropping practice and increase little by little, but it was always lower than non-dropped one. CO₂ increased to 4.9% just after dropping practice and decreased gradually but it was always higher than non-dropped one.
4. The concentration of dissolved O₂ in the flesh increased evidently with the increase of repetition of drops unless the fruit was waxed after dropping practice.
5. In case of dropped fruit, the ratio of DHA to total ascorbic acid in the flesh increased with the increase of repetition of drops during the shelf time after dropping practice.

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In order to obtain the best method for groping and picking operation of cocoon filament ends, the problem was analysed and discussed from three different view points: (1) the unit quantity of the cocoons being processed, (2) the processing method, and (3) the unit processing time.
The results obtained were as follows:
(1) The unit quantity of cocoons being processed. The working efficiency of both groping and picking operations with a single cocoon was found better than that with a large quantity handled in a single operation.
(2) The processing method.
In both groping and picking operations, the cocoons to be processed were fed continuously toward the stationary groping brush and picking hook. In this manner, the working sequence was made continuous and simultaneously increased its efficiency.
(3) The unit processing time.
In both groping and picking operations, each working time should be performed within a fixed period which allows an optimum length of the filament to be picked, thereby preventing the cocoon from being floated during the operation.

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The development of rice-hulls-combstion furnace was studied for the purpose of heat use.
With char-coals of that by-products the practical scale appartus, filtering filthy water of livestock waste, is studied in a separate way.
This paper reports the study results of characteristics which char-coals indicates on using as fiter. Seven kind materials, classfied into rice-hulls and its charcoals, each burning and crushing rate, became the object of the study. Fundamental material values related to filtering characteristics, were investigated.
With the same materials, under each pressure conditions, the flow resistance and compression strain were obtained and applied to Kozeny-Carman equation in oder to calculate imaginary capillary tube diameter of compression layer of every material.
In case of practical apparatus, final pressuring was calculated with the relation between flow rate and layer thickness.
Function of the filter layer was clarified.

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Early works on the use of radiation in agricultere concentrated mainly on the preservation of food by mean of the action of radiation sterilization. However, it takes a long period to establish the practical use of radiation preservation.
Recently, the nuclear methods of increasing food and reducing food losses are being watched with keen interest. Among then, the radiation method of agriculture has been successfully demonstrated in various applications.
It is absolutely essential to cut down the present huge losses occuring during the transportation and storage of the agricultural products. In order to prevent these losses, the radiation treatment of the agricultural products is quite effective as compared with the conventional methods, such as heat treatment, refrigeration and application of chemicals. Some examples, the radiation treatments on the sprout inhibition of potatoes, the control of insect population, and the sterilization of processed food are discussed.

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