The tests were conducted in order to find the relation between the traction of the farm tractors and soil shear strength, and to decide the field surface condition which improves a tractive efficiency, or to obtain the data used in the improvement of tractor design. The summarized results are as follows. 1) If the traction were generated by the soil shear strength, the maximum thrust per unit contact area tmax (kg/cm2) should agree with the shear strength s=c+ptanφ (kg/cm2), but the latter was generally larger than the former. It is because the shear did not occur all over the contact area and the thrust was also influenced by the friction between a running element and soil, especially because the soil values obtained by Soil Value Meter TN-4 tended to take a pretty larger values. 2) The thrusts of the crawler and semi-crawler tractors were represented by H=Hmax (1-e-i/K′), but those of the wheel tractors and girdle were expressed by H=Hmax-a(2-logi), where H is thrust (kg), Hmax is maxmium thrust (kg), i is slippage (%), K′ is slip coefficient (%) and a is constant depend on tractor size and soil condition. However, the both curves of a thrust per unit area vs. slippage showed the same figure and were similar to the shear stress-strain curves. 3) The relation between the sinkage and the slippage was linear. 4) The relation of the cone penetraitng resistance to the motion resistance of tractor on a muddy field was substantially linear. As a conclusion, it may be difficult to indicate the tractive effort of tractor by the Coulomb's equation which shows a soil shear strength, and we must consider more microscopic and local effect. Furthermore, it is considerably danger to predict the traction curve from the shear stressstrain curve of soil, because the shear of soil under a running element is not simple as that in shear box.
The necessity of paving for farm roads have been recognized in recent years. In this research, the two kind of test roads were made on the sanddune field, that is the mixed aspfalt paved road and the emulison macadam paved road. And on those test roads, the experiments have done in regard to the running performance of the farm vehicles (wheel type and track type farm tractors, motor truck, etc.). The results of those experime nts were as follows: 1) On the resistance of running of farm vehicles, the difference of it for both kind roads was not recognized. 2) On the distribution of tread pressure in the soil, the direct tread pressure at the point under tractor wheel in the case of emulsion macadam paved road was larger than that of the case of mixed asphalt paved road. 3) On the scar of track shoes of tractor, the road surface of emulsion macadam paved road was severely scared, as compared with the case of mixed asphalt paved road.
The static characteristics of flat, conical and ball valves which supplied the effective head varied in 6 stages from 40cm to 140cm, were described in this report. The discharge Q was measured at each valve lift h under a constant effective head H. From these experimental data, thus nondimensional discharge q0, coefficient of discharge C and coefficient of resistance ζ0 were computed and expressed as functions of opening ratio h/d0. (d0: valve-port diameter) The following results were obtained. 1) The discharge Q increased with the increase of effective head H. 2) The non-dimensional discharge q0 increased with the increase of opening ratio h/d0. 3) The coefficient of discharge C was the maximum valve in the range of opening ratio h/d0=0.02-0.035, but not exist the maximum valve in the ball valve. 4) On the coefficient of resistance ζ, the ball valve was found the influence of valve-port diameter.
Some physical properties of rice plant during milk ripe stage as related to machine design or farm work were investigated. Tests were made on normal plants selected from five plots, consisting of ordinary, glutinous rice variety, heavy fertilizer, dense planting and bordering plants. The loads to obtain the value of bending, compressive and tensile stress were applied at the center of the 3rd or the 4th internode from the apex of the culm. The apparatus used to apply and measure loads was the tensile tester “Tensilon” and penoscillograph. The results were as follows: 1) The average bending stress values were differed according to the measuring internode and the plot. Comparing the values obtained from each plot, the bordering plot was the maximum and the glutinous rice plot was the minimum. The significant differences among other plots were not indicated by their value. The stress values from the 3rd internode were larger than those from the 4th one. 2) The compressive stress values from the 3rd internode were larger than those of the 4th one, except for the ordinary plot but the stress characteristic of each plot was not indicated. 3) The maximum tensile stress was obtained from the glutinous rice plot. No significant differences obtained from the remaining plots. 4) There was a deep relationship between the degree of lodging and the bending stress value. The larger the value the smaller the degree of lodging.
The effects of the process of Citrus sorting machine on the preserving performance of Citrus Unshu, regard being had especially to brushing parts, were investigated and the following results were obtained: 1) As regard to decay: In the order of extent (1) Citrus applied with wax or “flavour seal” by brushing in the process of sorting (citrus applied by brushing), (2) Citrus applied with wax or “flavour seal” by soaking in a short time. (Citrus applied by soaking) (3) Non-treated citrus. (Fig 2) 2) Regarding loss in weight: At the storage of 15°C, citrus applied with wax by brushing was the least (Fig 3-1, 2). At the storage of 20°C, citrus applied by soaking was the least, and the others were complicated (Fig 3-3). 3) Regarding contractility: Citrus applied with wax by brush was the least. Citrus applied with “flavour seal” by brush was nearly equal to non-treated citrus. Citrus applied by soaking was small comparatively. (Fig 4) 4) The citrus applied with wax or “flavour seal” (now these citrus were named “applied citrus”) with the lapse of time, in contrast with this, non-applied things were hardening. (Fig 5) 5) The rate of juice to citrus weight was decreasing with the lapse of time. This tendency was more remarkable in the applied citrus than the non-applied things. (Fig 6) 6) The applied citrus showed puffing with the lapse of the time, but scarcely changed colour. In contrast with this, non applied citrus showed the peel adhering to the carpell wall and passed into dark brown. 7) Respirating intensity declined with the lapse of time. This tendency was appeared remarkably in the applied citrus. (Fig 7) 8) Citric-acid in citrus was decreasing with lapse of time. But the effect of application to citric-acid was not recognized evidently. (Fig 8) Total sugar in citrus was increasing with lapse of time, This tendency appeard remarkably in the citrus applied with “flavour-seal” by brush, but the citrus applied by soaking changed scarcely. (Fig 9) 9) The rate of citrus acid to total sugar was increasing remarkably, in applied citrus by brushing, especially in citrus applied with “flavour seal”. Citrus applied by soaking was nearly equal to non-treated citrus. (Fig 10)
Lavoratory scale model of vacuum cooling, by using desiccator, was devised, and the precise characteristics of vacuum cooling concerning the effect of packaging, pre-moistening and crop difference of Japanese perishables were investigated. (Fig 2) 1. The change of air pressure, product temperature and water loss of crop in desiccator, following the evacuation of air were observed every moment. (Fig 3) 2. In completely closed packaging, the fall of temperature of crop was prevented owing to the evaporated moisture. Pre-moistening on the surface of crop in case of vacuum cooling, is very effective both for reducing the weight loss and maintaining the freshness. (Fig 4) 3. Vacuum-cooled temperature differed due to the kind of crop, packed into the unperfolated polyethylene bag, and influenced much due to the sealing. (Fig 5) Cooling mechanism of the vacuum cooling were stated compared with other cooling. 4. The temperatures of the parts of crop in vacuum-cooling were measured. (Fig 6) (1) The difference of temprature by 2.5°C occ-ured between the parts of lettuce. (2) On the progress of vacuum-cooling of Brussels sprout, the temperature of the outer layer was lower than the center by 1°C, while the tend-ency was inversed with the stop of vacuum-pump. (3) The temperature distribution in the crop by vacuum cooling, was not affected much due to the packaging, pre-moistening of the crop.