Tractive performance of wheel type tractor operating directly uphill was investigated, basing ground-to-tire interaction:
1. Traction equation for front-(i=1) and rear-wheels (i=2) is expressed as:
F_i=(C_i+λ_i·ζ_{max, i})f_i(s_i) (i=1, 2)…(1)
where, F_i is the traction component of soil reaction, C_i the adhesion, ζ_{max, i} the maximum value of tractive coefficient at a driving wheel, and f_i(s_i) the function of s and ground-to-tire coefficients. Then, supporting components of the soil reactions λ_i against the front or rearwheels when the tractor is operating uphill are expressed as λ_i(s), which is the function of s, ground-to-tire coefficients and slope of the field φ, eliminating F_i and D (tractive force) from Eq. (1) and three equations of motions of a tractor.
In this paper, C_i and ζ_{max, i} are also called ground-to-tire coefficients.
2. Substituting Eq. (1), λ₁(s), and λ₂(s) into the force equation in the direction of motion, the tractive force of tractor D_T [kg] is expressed as:
D_T=∑²_i=1(C_i+λ_i(s)·ζ_{max, i})·f_i(s_i)-W(sinφ+x/g)…(2)
where, W is the weight of tractor and x the travelling acceleration. In case of rear-wheel-drive tractor, C₁=0, f₁(s₁)=-μ₁/ζ_{max, i}.
3. Tractive coefficient of tracfor ζ_T is expressed as:
ζ_T=D_T/W…(3)
4. Tractive horsepower of tractor H_D is exprssed as:
H_D=D_Tx/75=D_T/75·A_i(1-s_i)·θ_i(i=1, 2)…(4)
where, A_i [m] is the rolling radius of a wheel and θ_i [rad/sec] the rotating speed of a wheel.
5. Power coefficient of tractor indicating output power of traction work ξ_T is expressed as:
ξ_T=ζ_T(1-s₂)…(5)
6. Brake horsepower of tractor engine H_E is expressed as:
H_E=A₂/75Ξ·Q·θ₂…(6)
where,
Q=Q₁+Q₂
Q₁=1-s₂/1-s₁{I₁·θ₁/A₁+(C₁+λ₁(s)·ζ_{max, 1})f₁(s₁)+μ₁·λ₁(s)}
Q₂ I₂·θ₂/A₂+(C₂+λ₂(_s)·ζ_{max, 2})f₂(s₂)+μ₂·λ₂(s)
Ξ is the transmission efficiency, I_i the mass moment of inertia about axle and μ_i the coefficient of rolling resistance. In case of rear-wheel drive tractor, Q₁=0.
7. Tractive efficiency of tractor η_T is expressed as:
η_T=H_D/H_E=Ξ(1-s₂)D/Q…(7)
Parameter η_T expresses power efficiency of traction work of tractor.
8. The relations between η_T and ζ_T, and ξ_T and ζ

View full abstract

A mathematical model for predicting the steering response of articulated vehicles has been developed and computerized for numerical application. The model contains some of the basic parameters govering the respones of articulated tracked vehicles, such as slippage, centrifugal forces, vehicle characteristics, the point of articulation and the mass ratio of rear vehicle to the front one.
The model has been verifed by means of scale model response tests.
The computer program has been used to parametrically investigate the steering response of specific vehicles in different turning conditions.
It is shown that the ariticulation point, the mass ratio and the steering delay of the rear vehicle to the front have a strong effect on the turning characteristics of the articulated tracked vehicles.

View full abstract

Field tests of deeper rotary tillage were done in clay soil and sandy soil, and following results were obtained.
1) When the rotational directions and the ratio of tilling depth to rotor radius (H/R) were changed, four tilling patterns that had different characteristics of throwing tilled soil backward respectively were observed. (Fig. 5, 7)
2) Throwing tilled soil was superior when down cut tilling under H/R smaller than 1.0 and up cut tilling under H/R greater than 1.0. The former might be favorable for common rotary tillage, the later might be favorable for deeper rotary tillage.
3) Tilling reaction force acting on a blade was the largest when the bottom soil was cut upward by the curved blade portion on both cases of down cut tilling and up cut tilling in sandy soil.
4) On the case of up cut tilling under H/R greater than 1.0, it might be important for design of rotary tiller for deep tillage that the shapes of a blade and tilling cover should be improved to throw the soil better.

View full abstract

The experiment was carried out to examine the number of operational procedures, required power, pulverizing property and ridge height, when the pulverizing device with a rotary tilling tine attached to a horizontal screw type blade was set and used for ridge-making operation, and the various characteristics as the one process ridge-making machine were investigated.
(1) The arrangement of the tine of the pulverizing device was made such that the tine was attached symmetrically in left and right sides in relation to the shaft center and directed inwards, so that the ridge-making effect was not reduced. When the cover (apron) for preventing scattering was attached to the rear of the pulverizing device, the pulverizing effect was somewhat improved, but the required power increased rapidly, and the operation sometimes became impossible.
(2) The required power was 6-20 PS when the tilling width of the blades was 145cm, the tilling depth was 13-18cm, and the tilling pitch was 10-20cm, and also the width and depth of action of the pulverizing device were 85-110cm and 9-42cm, respectively. As the general tendency, the power increased in proportion to the increase of the number of revolution of the ridge-making shaft (the increase of tilling pitch) and the increase of tilling depth.
(3) The form of ridges was affected by the presence of the apron, and it was triangular when the apron was not used, but it was changed to semi-cylindrical form as the top of ridges fell in when the apron was used. The ridge height changed with tilling depth, and turned out to be 30-40cm when the tilling depth was 13-18cm (without the apron). But the difference according to tilling pitch was scarcely observed.
(4) The vibration of the machine body during operation decreased linearly as the number of revolution of the ridge-making shaft increased, and the amplitude was 2.0-0.5cm at the portion of the machine body with large amplitude, thus it was found that operation can be carried out stably.

View full abstract

A small-sized lotus-roots harvester using a stationary water pump was built with the object of being adapted for individual farm use and its performance was tested. The results were summarized as follows,
1. This machine could be used on the drained field with water supplied through a long hose by a pump fixed on border levee or farm road. The main parts of this machine consisted of two nozzles arranged in front and rear doing the fan-shaped reciprocating motion and self-traveling device.
2. In order to harvest lotus-roots perfectly, the required momentum of water jet per unit area was more than 3, 000kg·s/m² as was in I-type trial machine, but the value could be decreased up to 2, 000kg·s/m² by adding hand pulling.
3. In order to keep lotus-roots from broken loss under the constant momentum of water jet, it was advantageous to arrange nozzles in front and rear.
4. This machine harvested lotus-roots at the rate of 0.25a per hour, which was about 3 times as much as that by hand.

View full abstract

The following were learned from the results of experiments conducted seeking to find the appropriate sowing depth for Calper-coated seed rice.
1. As the sowing depth becomes deeper, the first leaf sprouting rate drops and plant height and dry weight are reduced.
2. If the sowing depth is too shallow, the seeds float to the surface after planting. If the seeds are sown at the depth of 8-12mm or deeper, however, almost no seeds float so the surface.
3. It is important to plant after soaking the seed well in the water. It is not necessary to germinate the seed before planting.
4. Even if sown early, when it is cold, germination will not come earlier.
5. If the bases of the rice plants are covered by even a little soil, it is possible to prevent the toppling over of the rice plants at their bases.
6. With cultivation involving direct planting of seeds in submerged paddy field, it is necessary to sow seeds of high specific gravity.
7. It is thought that the sowing depth of around 10mm is appropriate for paddy field direct-planting cultivation.

View full abstract

With the aid of the test stand mentioned in Part 1 and using four commercial types of saw chain, i. e. chipper type (51CP-75E), semi chisel type (72DP-81E) and chisel typer (72LP-81E & 76LP-81E), the characteristics of wood cutting force of the whole saw chains were investigated. The material tested here is spruce produced in North America with rectangular cross section of 20cm×20cm and moisture content of about 14 percent. As already mentioned in Part 1, the measured forces to cut timber were independent of the frictional resistance between the saw chain and bar rail and the reaction of the discharged saw dust in this experiment. The results obtained are as follows:
1) To carry out the cutting experiments, the velocity of the saw chain V_H was set in the range of 2.2-17.6m/s and feed speed V_V 1.7-16.1mm/s. The velocity and the feed speed were examined in various combination to obtain a wide range of velocity ratio λ. As a result, it was clarified as shown in Fig. 6-9 that the relation between the velocity ratio λ and the tangential cutting resistance force F_H and the normal cutting resistance force F_V could be expressed by following empirical formula.
F_H, F_V=c/(λ+a)+b
where a, b and c are the constant obtained from the experiment
By this formula, of the velocity ratio λ can be kept constant for timber cutting, the tangential cutting resistance force F_H and the normal cutting resistance force F_V can be determined.
2) The ratio of the normal cutting resistance force to the tangential cutting resistance force, i. e. force ratio F_V/F_H, was proved to be independent of the velocity ratio λ and remained constant except for 76 LP type saw chain. It was also clear that F_V was one half of F_H and angle of the resultant force was about 26 degree as shown in Fig. 10, This angle indicates the direction of the resultant cutting force and the amount of this can be regarded as an index of the cutter tooth biting into the timber. From this viewpoint, the biting ability of 76LP type saw chain at high speed and light load, i. e. when the velocity ratio λ is in a larger region, becomes somewhat dull compared with the other three types.
3) To compare the ease of cutting for the tested four types of saw chains, a specific cutting resistance force per one cutter tooth f_H was examined. As an undeformed chip thickness δ becomes a function of the velocity λ, the relation between δ and f_H was investigated as shown in Fig. 11. As a result, 72LP type saw chain was found to be the sharpest followed by 76 LP, 72DP and 51CP in that order.
4) Based on the facts described above, net cutting horsepower vs. engine speed and feed rate was calculated from the standpoint of effective usage for a one man gasoline engine chain saw. Furthermore, taking a few factors into consideration, a method to obtain brake cutting horsepower requi red to drive a saw chain was suggested.

View full abstract

Increasing the size of the animal feeder has created a problem of wastes management. The feasible systems are desired for wastes management and utilization.
Authors developed a compact experimental device in order to recognize the composting mechanisms and suitable composting conditions. The results of this paper were as follows.
1. In order to conduct the satisfactory experiments with the compact device, adiabatic treatment was performed for the compact composting container and the surrounding temperature of the container was kept automatically almost equal to the material temperature. As the result, the material temperature could rise as high as that of the practical composting.
2. In the practical composting, the conditions of composting had to be recognized from the partial date of material conditions. Since composting was advanced uniformly in this container, authors could recognize the data of whole material conditions. Consequently, more effective experiments. could be carried out. The data obtaned from this method were considered to correspond to those of the practical composting.
3. The pattern of material temperature rising formed very often a curve which had two peak values. There was a significant correlation between the value of the first peak and the value of the second peak.
4. The values of the two peaks corresponded to the activity of the mesophilic and the thermophilic bacterias.
5. Measurement of the moisture content and the weight loss, and ingredient analysis of the exhaust air made it possible to divide the weight loss into the moisture loss and dry matter loss. The results showed the possibility of clearer analysis of the composting mechanisms.

View full abstract

To clarify the adaptability and the utility of the multi layer passing type dryer for naked barley, the processing efficiency of drying and pearling aptitude were investigated in different periods of harvest (moisture contents of grain) and forcedair temperatures.
Examination, of which tested grains were harvested by head feeding type combine, was practiced with a miniature dryer (Fig. 1) under the constant air flow rate of 0.10m³/s·100kg.
1) Periods of harvest and properties of naked barley
This experimentation was practiced in May 1979, and the month was unusually favored by fine weather, so that the drying rate of the standing naked barley was got to 5-6%/day (Table 1).
As the period of harvest was earlier, the containing rate of the unhulled grain increased the apparent density decreased (Fig. 2).
The higher was the moisture content of grain, the remarkably larger was the volume contraction with drying. The contraction ratio came up to about 60% in case of about 40% moisture content of grain, and about 75% in case of about 30% m. c. (Fig. 2).
2) Drying efficiency
We intended to have 3-4 layers of piled grain. But in case that the high moist grain was piled, the moisture absorption had occurred in the top layer under the condition of air flow rate 0.1m³/s·100kg (Fig. 3).
The higher was the moisture content of grain and the forced-air temperature, the more decreased the allowable number of layers of piled grain (Fig. 4).
In case that the air flow rate was 0.1m³/s·100kg, the processing efficiency of drying remarkably decreased with the initial moisture content of over 20-25% (Fig. 5). In case of the high moist grain, the processing efficiency of drying was slightly influenced by high forced-air temperature (Fig. 5).
3) Dignity and pearling aptitude
(1) Period of harvest, forced-air temperature and dignity-pearling aptitude
As the period of harvest was earlier, whiteness and powdery of grain increased and dignity deteriorated. Also lowering in the yield of pearled grainn and increasing in the rate of small pearled grain were remarkably recognized (Table 3). The unhulled grain was generally good for the dignity and pearling aptitude. But it had high hardness and needed long pearling time (Fig. 8, Table 4). As the period of harvest was earlier, the containing rate of unhulled grain increased, therefore it caused the irregularities in size and in colour of pearl barley. From the results mentioned above, in order to hold quality, the harvesting with combine should be practiced for naked barley under the moisture content of grain of 30%.
Forced-air temperature did not so influenced the dignity and pearling aptitude, except that the small pearled grain increases in the case of 75°C But forced-air temperature sensitively affected on the germination ratio. The germination extremely deteriorated in case of 75°C (Table 3).
(2) Harvesting systems and dignity-pearling aptitude
The binder-harvest system was particularly superior to the combine-harvest system on the dignity and pearling aptitude of naked barley, and the deterioration of dignity and pearling aptitude was scarcely recognized even in early harvesting (Table 5). From this result, it was considered that ear cutting-predrying-harvest system (tentative name), which was shown by the following working series, reaping-ear cutting→predrying-heating→threshing→final drying, would be effective.

View full abstract

In order to determine the stress relaxation modulus of a rice kernel, the uniaxial compression and the stress relaxation tests in the same manner as the previous work were carried out by using the rice endosperm pieces formed into a cylindrical shape under various temperatures and moisture contents of the pieces. The results obtained were summarized as follows:
(1) By applying the compressive force to the length, the width and the thickness directions of the rice grain, it could be considered that the rice endosperm was nearly isotropic.
(2) Within about 1% of the strain, the compressive (tensile) relaxation modulus E(t) and the shear relaxation modulus G(t) were experimentally given by the following equations,
E(t)=1.02×10⁴/Tw{0.3exp[-0.0198exp(0.02T+11w)t]+0.7exp[-0.000833exp(0.02T+11w)t]}
and
G(t)=8.16×10₂/Tw{0.3exp[-0.0198exp(0.02T+11w)t]+0.7exp[-0.000833exp(0.02T+11w)t]}
respectively, where T: temperature [°K], w: moisture content [kg/kg-dry solid] and t: time [hr]. These equations were valid in the ranges 293<T<323 and 0.10<w<0.35.
(3) By assuming that the rice endosperm was a thermo- and hydro-rheologically simple material, the master curves for the relaxation moduli of the rice endosperm were given by the following equations,
E₀(ξ)=205[0.3exp(-45ξ)+0.7exp(-1.9ξ)]
G₀(ξ) =164[0.3exp(-45ξ)+0.7exp(-1.9ξ)]
where E₀(ξ): the compressive relaxation modulus at the reference temperature T₀(=293°K) and the reference moisture content w₀(=0.17d.b.), G₀(ξ): the shear relaxation modulus at T₀ and w₀, and ξ: the reduced time [hr] (ξ=4.39×10^-4exp[0.02T+11w]t).

View full abstract

This study was concerned chiefly with separating capacities of brown rices and sands, using a sand separator with a combination of a drawing and blowing fan and with a blowing fan. The sand separator consisted essentially of a screen and fan. The differences of the static pressures, wind velocities, frequencies, feeding rates of the brown rice and sand sizes might be considered as the main separating factors. River sands which were screened with a standard sieve and ranged from 1.41mm up to 5.66mm, and painted by water colors to clearly distinguish sands from brown rices were used as the experimental materials. The number of sands used was 50 grains a test.
The main results were as follows;
1) Use of the sands painted by water colors made easy to distinguish sands from brown rices.
2) In the case of a combination of drawing and blowing, the cumulative recovery of sands was deeply concerned in the wind velocities of drawing, feeding rates of the brown rice, differences of static pressures and frequencies.
3) The screening time that the cumulative recovery of sand became 100% decreased gradually with the increase of the difference of static pressures, and it arrived at the minimum value, and then it gradually increased. Generally speaking, in the condition of higher value more than about 10mm Aq in the difference of static pressures, the cumulative recoveries might be high values by and large.
4) It was clear that a high recovery of sands was deeply concerned in the condition of fluidizing of the brown rice bed.
5) The discharging rates of brown rices in the discharge end of sands decreased gradually with the increase of the difference of static pressures.
6) The flowing velocities of brown rices might be largely influenced by the differences of static pressures rather than frequencies of the screen.
7) The flowing distance in the brown rice bed of sands subjected to the influence of the flowing velocities of the brown rice and the depths of its bed.
8) It was clear that a combination of drawing and blowing was able to make dusts discharge easily, and its separating capacity was not less than that of blowing.

View full abstract