In applying Liquefied Petroleum gas for small size watercooled kerosene farm engine, we should let many advantagious points which LP gas has in it work fully. Paying special attention to the greatest merit of LP gas that anti-knock is high, we changed an actual cylinder-head to three new ones, in order to rise thermal efficiency; compression ratio 5.2, 5.7, 6.2. We measured fuel consumption, air-fuel ratio, temperature of every part of engine and noise etc, thus we compared with engine performances and considerd economical relation of both fuels; i. e., LP gas and kerosene:
(i) Relation between compression ratio and ignition timing: The following fact must be observed, that, under the same compression ratio, best ignition timing of LP gas became earlier about 5 degrees in crank angle than that of kerosene. As to the LP gas only, the higher the compression ratio rises, the slower the best ignition timing becomes. (Table. 3)
(ii) Air-fuel ratio and Excess-air ratio: In case of kerosene, air-fuel ratio was about 17, excess-air ratio was about 1.2. As to LP gas, however, it was respectively, 22 and 1.4. It seems that the differences of volatility, maximum flame velocity of both fuels, and the burning characteristics of those give influence to those values. (Figure. 6. diagram above)
(iii) Fuel consumption, Specific fuel consumption and Fuel consumption falling rate: Being based upon Figure. 6: fuel consumption falling rate, namely, falling rate of specific fuel consumption of LP gas to that of kerosene, showed a drop from 14 per cent to 18 per cent in compression ratio 5.2, 17 to 25 in 5.7, 23 to 30 in 6. 2. (Figure. 7). The reason must be that, in case of LP gas, the use of rarefied mixture-ratio is possible.
(iv) Operation cost: On the actual stage, though specific fuel consumption of LP gas is better than keroseen's, from 20 per cent to 30 per cent, its operating cost became about 35 per cent more expensive than kerosene's, because the net price of LP gas is about two times more expensive than that of kerosene. (Figure. 9)
(v) Temperature of every parts of engine: Combustion chamber temperature became higher by LP gas than by kerosene. As to LP gas only, as compression ratio rises, it became higher. Generally, exhaust-gas temperature used to fall down with rising of compression ratio. (Figure. 11). Concerning the relation between exhaust-gas temperature and ignition timing, as ignition timing is advanced, its temperature dropped down. (Figure. 12)
(vi) Engine noise: There was not a remarkable difference between kerosene and LP gas, and seems not to be so harmful to the human being.
As above mentioned, judging from such a method of rising of compression ratio taken in this experiment, if specific fuel consumption is 160g/PS-h, and thermal efficiency is above 35 per cent, too, LP gas will be more economic benefit than kerosene. So this shows that compression ratio must be above 8. It must be our concern of future research that taking into consideration a form of combustion chamber fitting to LP gas, we should try to rise compression ratio, and according to rising of compression ratio, we must try to rise charging efficiency so that mechanical efficiency may not drop down.

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The mechanics of soil-vehicle system that was based on the deformable properties of the soil and the sliding friction on the contact surface, don't agree with the practically.
Equation(1) can not be applied on non-uniform soil, in addition, the constant Kc have not rati onality on such uniform soil as dry sand. The relations of p and Z change by the sinkage velociy of the plate, so that the travel performance of the vehicle would be affected by it's travel speed.
The relations of normal component (P) and tangential component (S) of soil reaction force don't simply accord with the relation of the sliding fricton on the case of the contact surface on the wheel. The factors that are concerned with that's relations are the acting position of reaction force (θ), the apparent frictional coefficient and the slip of the wheel.

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The ground compressing system of the tracked vehicles is regarded as the two parallel strip loads.
Now, if load-distance between such two loads is sufficiently large, Terzaghi's solutin is app licable, but app roaching each other the two loads closer than a certain limit distance, the interference of the two loads takes place and prandtl's slip line field does not exist.
The studies on the bearing capacity for such load-system have been hardly performed in comparison with those for single strip load.
Then the authors deduced the following approximate equations for the bearing capacity of the two parallel strip loads, assuming that the soil weight is negligible.
(A) A/B≤1.429φ²+0.283φ+0.146
F/BC=F₁(1+A/2B)
(B) A/B≥1.429φ²+0.283φ+0.146
F/BC=F₁{1+(Fo-F₁)exp
(-A/B/0.05(10φ)1.35+0.303)}
where
Fo/BC={φ≠0: {(1+sinφ)⋅;exp[(3π/2+φ)tanφ]
φ=0: 5.712
-1}cotφ
F₁/BC…{φ≠0: {tan²(π/4+φ/2)⋅exp (πtanφ)-1}
φ=0: 5.142 cotφ
F: bearing capacity under two parallel strip loads.
φ: soil internal friction
C: soil cohesion
A: load distance
B: load width

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The torque control system which controls the resistant torque of the rotary tiller consists with the gear type torque detector, the control valve and the power cylinder. To find the control system responses to the periodical variation with a long period of time such as the change of the tillage depth by the tractor pitching, we made a ridge and a ditch on the field and then field experiments were done crossing them.
(1) Eliminating the components of short periodical variation such as each tine impact, the responses to the tractor pitching at the ridge and the ditch were good.
(2) As the tractor is running on the flat field after passing over the ridge, the response of the system is affected by the pitching on it and has the damping oscillation curve with over shoot
(3) The response of the system of which the spring constant k₁ is larger and the tillage pitch is smaller, is more stable and its torque variance is smaller. By the experiments it is obvious that the stability is higher but the sensibility is lower as the gain constant K of the system is smaller.
(4) Analyzing the damping oscillation curve of the rotary displacement on the flat part of the field, we obtained the transfer function of the system with smoothing inputs. This transfer function is the same type as the theoretical transfer function but has smaller gain constant and larger time constant.

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In order to make a better rice-seedling-band for the transplanting machine, tensile, shearing and bending stress of a soil-band with seedlings were detected.
Tests materials for each stress were kept approaximately in the same nursery condition during the test to obtain a most reliable data.
Some pertinent factors such as number of seedlings per unit length of band, type of soil used, moisture content, were related to each stress and their relationships discussed.
The results were as follows:
1. As the number of seedlings per unit length of band were increased, each stress showed a linear increased.
The influence of the number of seedlings appeared mostly in the value of tensile stress, next in shearing and bending stress respectively.
2. Within 5% degree of significance, the influence of two different bands of clayey loam and sandy loam over the stress were invisible. However, it was estimated that clayey loam band had a small influennce over the tensile stress.
3. Within 5% degree of significance, wet and dry band showed slight influence over tensile and bending stress, although dry band tended to increase the value of bending stress.
4. With conventional nursering conditions, the average value of tensile stress found at 293, 73g/cm², bending stress at 15.60g/cm², and shearing stress at 3100g/cm².
5. It is suggested, for the reason stated in (1), that good seedling-band of low shearing stress should have a proper balance of stresses mentioned.

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Mechanical properties of rice ear and grain were studied, which were of major concern in their proper handling; harvesting, drying and processing. The results were as follow.
1) Before dead ripe stage, there was a high positive correlation between stripping force (the tensile strength of abciss layer) and the moisture content of primary branch. Stripping force decreased in magnitude with a decrease in moisture content.
2) On the other hand, as moisture content decreased, the tensile strength of primary branch increased.
3) At dead ripe stage, there was not a correlation between moisture content and stripping force, as moisture content depends greatly on weather. But the distribution of stripping force is normal distribution, then knowing its universal average quantitative expression about the hardness of stripping is possible.
4) The angle between subsidiary empty glume and secondary branch was not a right angle. When this angle clossed to 90 degree, it required large stripping force. Stripping force was variable with the direction of tensile force.
5) The tensile strength of rice grain was much higher than compressive strength; at low moisture content the former was 1/10 of the latter and at high, 1/15. The fracture under compression, in, substance, is tensile fracture.
6) As moisture content increased, tensile strength decreased. At 20% moisture content the mechanical property of rice grain changes; at the lower moisture content rice grain is rich in elasticity and at the higher moisture content, in plasticity.
7) The rice grain of which moisture content is lower than 15% is elastic body and Young's modulus of elasticity values about 500kg/em².

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Experimental studies on the air-precooling of eggs were conducted and the following results were obtained.
1. Cooling rate of a single egg:
(1) Temperatures at the parts of an egg were not uniform in the cooling-air flow. Cooling rates of the parts of an egg were observed in the following order:
(1) upstream side (2) upper side (3) downstream and bottom side (4)center of egg.
Temperatures of the parts of an egg equalized earlier when the egg was positioned lengthwise than the one positioned crossway. (Fig. 3-(1))
(2) Cooling rate of egg increased with being smaller the egg, higher the air velocity and lower the air temperature, respectively, and was not much influenced from the degree of boiling of egg.
The lower the surrounding air temperature, the more sharp the fall of egg temperature.
If other conditions were fixed, however, the half cooling time of eggs was independent of the cooling-air temperature. (Fig. 3-(2) Fig. 4-(2), Table 1)
2. The relation between the egg location in container and the cooling rate of the egg:
(1) In room cooling, the cooling rate of egg in basket is lowerd with being the egg location nearer to the center of basket. (Fig. 5-(1))
(2) In air-blast cooing, the cooling rate of egg in basket is lowerd with being the egg located nearer to the bottom of basket. (Fig. 5-(2))
(3) The cooling rate of egg in basket, under parallel flowing air, is increased with being the egg located nearer to the bottom.
On the contrary, the cooling rate of egg in bucket is lowerd with being nearer to the bottom. (Fig. 5-(3))
(4) The cooling curves for the surface and center of an egg ran parallel in these method of air-cooling.
(5) Under the forced air cooling, the cooling rate of egg packed in carton consisisting of fillers-and-flats was lowerd with being the egg nearer to the center of carton, but the temperature gradient in egg was minimized. (Fig. 5-(4))
3. (1) Cooling rate of egg due to the kind of container was seen in the following order:
1 basket, 2 bucket (made of tin-plate), 3 polyethylene bucket. Cooling effect of air-blast was greater than the effect of parallel flow. (Fig. 6-(1))
(2) The cooling rate was expedited by perforating through the bottom plate of bucket. It is sufficient to perforate 20 holes of 13-mm diameter.
(3) The cooling rates of the center of centrally located eggs in three kind of packing systems were compared. (Fig. 6-(3))
4. The effect of air rate on the cooling rate of eggs in container was investigated.
The effect was more remarkable when the air rate was increased from 0 to 1.5m/sec compared with the one from 1.5 to 3 m/sec. (Fig. 7)
5. The relation between the air velocity and the cooling rate of stacked eggs: The value of m and the cooling time required to reach Y=0.1 (Y: Remaining fraction of initial temperature difference between eggs and cooling-air.) due to the cooling-air velocity were investigated. Cooling efficiency was not much increased by using air velocity larger than 4∼5m/s. (Fig. 8)

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For the purpose of measuring the effective the-rural diffusivity of anomalously farm products, the paraffin-wax-model method in comparing the
coolin curves of the farm products and that of itis paraffin-wax model, was used.
The diffusivity is calcuated using the following equation:
κ_o=κ_pm_o/mp (1)
where κ_o: the effective thermal diffusivtiy of the farm product.
κ_p: the thermal diffusivity of the paraffin wax.
m_o: the slope of a plot of the logarithm of the temperature against the time of the cooling curve of the product for the condition of negligible surface thermal resistance.
m_p: The slope of a plot of the logarithm of the temperature against the time of the cooling curve of the paraffin-wax model for the condition of negligible surface thermal resistance.
The equation is correct for the condition of negligible surface thermal resitance because the eigenvalue of the Fourier series solution of Fourier heat conduction equation is only the function of the geometrical shape and the slope is the pro-duct of the eigenvalue by the thermal diffusivity.
The measuring procedure is as follows:
1) The product is immersed into the agitated ice-water bath and the temperature of the product near the center is measured and recorded with a recorder employing C-C thermocoupls.
2) The paraffin-wax model of the product is made by pouring molten paraffin wax into the mold made with the plaster.
3) The model is immersed into the bath and the temperature near the center is measured and recorded.
4) The effective thermal diffusivity is calculated from the slopes of the cooling curves of the product and it's paraffin-wax model and the known thermal diffusivity of the paraffin wax using the equation(1).
By this method, the effective thermal diffusivities of Egg (Gifu-Jitori), Egg (Leghorn), Onion, Carrot and Eggplant were determined.

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The extruding force (=F), expansion ratio(=e), the changes of moisture content (=mC) and final dry weight density (=ρd) were measured on the various mC, ρd, compressing time (=t), forming diameter (=D) and height (=H) of ladinoclover and orchardgrass, and the following results were obtained.
(i) Extruding force: F
1. It increased with the increase of ρ_d, mC and t.
2. The assumed coefficient of friction (=μ) and the rate of extruding force (=i=F/P, P: maximum compression force) decreased as ρd in-creased and mC decreased.
3. The i decreased but μ almost unvaried with the increase of D, tnen F and i increased with the increase of H if D was equal.
4. The ratio (≅i) of cylindrical friction per compression force P was respectively 1-3%, 2-10% and 2-15% in response to moisture contents were low, middle and high,
(ii) Expansion ratio: e
1. The wafer of hay expanded quickly as soon as it was extruded, thereafter expanded slowly by reason of the absorption of moisture in case of low mC, but if mC was high it shrinked passing through a maximum volume due to drying.
2. Each expansion ratio of diameter, height and volume (eD, eH, eV) and the expansion rate per t decreased with increase of ρd.
3. After fifty days, eH was inversely proportional to P, generally, any e was larger as the moisture content was lower, but e of orchardgrass was larger with increase of mC during one or several days after forming.
4. The expansion ratio of orchardgrass was about as large again as ladinoclover, because the fibration of orchardgrass was much and the elasticity were larger than those of ladinoclover.
5. The eH was about six times as large as eD, and eV was affected mainly by eH. That is, the wafer of hay formed by the cylindrical compression method expanded almost only towards the direction of height, 1.5-2.5 times at ladinoclover and 2.5-4.5 times at orchardgrass after fifty days, but the increase of eD was very little. At the same condition, eH was reduced as H increased and as D decreased at high moisture content. In generally, eD increased in proportion to D.
6. The low moisture hay was undesirable from the view point of durability because e was large in spit of the small compression force.
7. As t became longer, e decreased at low mC but almost unvaried at high mC and F slightly increased and the efficiency decreased, then the improving effect of durability was diminished.
8. It was considered that the constant pressure compression (P const, ρ_d increase) was more desirable than the constant volume compression (ρ_d const, P decrease).
(iii) Variation of moisture content and density
1. The mC of waffers gradually increased as time went by when mC was low, but it decreased if mC was middle or high, and mC of wafers in any condition gradually approached to a certain value peculiar to kinds of materials after they were left in the air for fifty days.
2. The ρ_d of wafers decreased to about 1/5-1/10 or less, especially at orchardgrass, and ρ_d of high moisture ladinoclover reduced to about a half after fifty days.
3. It was significant that the each value of e varied according to the conditions of forming and affected durability, regardless of the equality of mC after fifty days.

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