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Volume 51, Issue 6
Displaying 1-17 of 17 articles from this issue
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Y. KISHIDA1989 Volume 51 Issue 6 Pages 1-2
Published: 1989
Released on J-STAGE: April 30, 2010
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G. Rajaram, A. Oida1989 Volume 51 Issue 6 Pages 3-11
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe failure phenomena associated with tine implements in agricultural soils were observed. The observed nature of failure was found to depend on the type of soil, the soil moisture content and tine dimensions. Based on the observations in clay and sand, the failure mechanisms were classified into five distinct types, namely, Collapse, Fracture, Chip-forming, Plastic Flow and Frictional Flow. The Collapse and Fracture failures were cyclic phenomena, and the corresponding draft forces were perfectly cyclic when measured accurately. The Chip-forming, Plastic Flow and Frictional Flow were all steady-state phenomena, and the corresponding draft forces were steady-state. In all cases, the mechanisms of failure did neither resemble those prescribed by passive earth preesure theories nor adequately predict the draft forces encountered by agricultural tines.View full abstractDownload PDF (10272K) -
Isao TAJIRI, Kunio SATO1989 Volume 51 Issue 6 Pages 13-20
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSWhen higher response speed of inclination control is intended, slope tractor equipped with an inclination sensor of pendulum type often shows excessive fluctuation of tractor inclination. This occurs when the specification of the damper is inappropriate and because the pivot of the sensor pendulum is fixed on a point of the tractor.
To meet this problem, two methods are proposed and discussed about frame models, which allow the pivot point to move in relation to the tractor body. In the first method, the pendulum is set on a parallel link mechanism of front wheel suspension. when the tractor is controlled horizontally, the pivot point keeps almost same position against the surface of the terrain, and facilitate sensing of inclination on the terrain. In the second method, the pendulum is pivoted on a link of the trailing arm suspension of rear wheels, and the pivot point moves to the direction of inclination in relation to the tractor body. These both methods reduce the oscillation of the pivot point, and facilitate proper damping.View full abstractDownload PDF (3402K) -
Automatic Control of Tractor-Implement SystemIkjoo JANG, Osamu KITANI, Tsuguo OKAMOTO, Satoshi YONEKAWA1989 Volume 51 Issue 6 Pages 21-28
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSReduction of energy requirement was achieved by automatic control of tractor-implement system. For this purpose algorism and program to control the rotational velocity of disk blade were developed and field tests were conducted to perform the most effective use of tractor fuel with more soil pulverization. Simulation was also made to clarify general characteristics of the control system. Reduction of tractor fuel by 2.5-10% was achieved in the field teste.View full abstractDownload PDF (3825K) -
Comparison between Two-Mirror Method and Rearview MirrorYoshinobu OHTA, Tatsuo HIROMA1989 Volume 51 Issue 6 Pages 29-36
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSComparison of the visual range on the rear of tractor by images through 3 types of conventional rearview mirrors, and through 3 sets of two plane/convex mirrors which were cited as twe-mirror method in the previous report, is presented.
For the evaluation of visual perception, pattern boards were spread out on the ground behind tractor, and vertical pattern plates were stood at each point on the pattern boards. Detailed sizes of distorted mirror images of horizontal or vertical patterns were measured.
The two-mirror method was advantageous to watching rearward area rather near by the tractor, though with a slight shorting of image in the longitudinal direction. In the case of rearview mirrors, the indirect visual range covered the area from the side of tractor rear wheels to the central part of tractor rearward, but the area around the lower hitch points remained as a dead angle of view. The mirrors gave images lengthened in the vertical direction.View full abstractDownload PDF (4107K) -
On the Fundamental FunctionsMinoru KOMATSU, Hideo HIGUCHI1989 Volume 51 Issue 6 Pages 37-44
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThis report is a developmental study on a traction aid of adjustable lug type that consists of a four-bar constrained chain mechanism. The device is mounted on the outside of both driving rear wheels of tractor, and its degree of action is operated by the hydraulic force of the tractor.
Intended advantages of the device are listed as follow. Appropriate shape of lugs and their angle of action can be chosen according to field conditions; Their control is easy and speedy either on field or on road, or in running on soft ground; Adjustment of inclination of tractor body is possible while driving on sloping land, which leads to prevention of sideslips and roll over accidents; The device assists easy escape of tractor from standstill due to sinkage; Soil compaction is reduced both in soil preparation and in running between crop rows; Due to lug action, high traction is achieved and trafficability is secured even on soft field conditions.
In this first report, the principle of adjusttable lug mechanism and its fundamental functions are presented. Field performances will be discussed in the next report.View full abstractDownload PDF (5710K) -
Turning Behavior on Concrete Paved GroundAkira OIDA, Hiromichi ITOH1989 Volume 51 Issue 6 Pages 45-53
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA turning behavior of a 4WD-4WS farm tractor was analyzed by forming three equations of motion of which main parameters were a tractive force and a cornering force. In these equations dynamic weight transfers due to forward and lateral accelerations during the turn were taken into account. After solving the equations by the RUNGE-KUTTA-GILL method, a side slip angle and a yaw angular velocity of and around the center of gravity were got for a certain steady condition.
Using above equations, the turning behavior was simulated by a computer and effects of steering angle, running speed, tire-ground frictional coefficient and position of the center of gravity on the turning behavior were analyzed.
Turning experiments to check the simulation were done and turning radii were measured. There were a little differences between the measured and the calculated turning radius.View full abstractDownload PDF (1118K) -
Masayuki KASAHARA1989 Volume 51 Issue 6 Pages 55-62
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe measuring accuracy of the moisture content detector that was developed as the control of circulation type dryer for rice and barley was influenced by grain properties and dry conditions. However, its primary factor is not made clear. In this paper, it was investigated that the effect of the properties, such as the mixing rate of immature rough rice, the fertilization quantity in paddy, the kinds of rice, the tissue structure of rough rice and the stability state of moisture, on the measuring accuracy of several moisture content detectors with each measuring methods. The results were as follows.
The meter readings of detectors were high with an increase in the mixing rate of immature rough rices because of its low resistance of high-frequency. The meter readings were scattered by kinds of rough rice for the reason that their husks had each individual electric characteristic. The lower the using frequency was, the more the meter readings were affected by the internal moisture incline of a grain. Meanwhile, the fertilization quantity in paddy had no effect on the meter readings of detectorView full abstractDownload PDF (1342K) -
Rokuro TOBE1989 Volume 51 Issue 6 Pages 63-69
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSConcerning quantitatve determination of the degree of maturity of bananas during artificial afterriepening, measurements were carried out on their electric conductivity and rheological parameters such as hardness, elasticity, brittleness, cohesiveness, adhesiveness and gumminess. The degree of maturity was evaluated with sugar content and pH, and through sensory tests as well. To discuss electric conductivity, a numeric factor ‘n’ was used, which was obtained from the observed current-voltage relation on the basis of the theoretical expression of current due to diffusion of ions:
I=I0[exp(ZFV/nRT)-1],
where R is the gas constant, ZF electronic charge, V applied voltage and T absolute temperature.
Sugar content, n and pH increased in process of days, and reached at a maximum value when bananas got edible.View full abstractDownload PDF (1103K) -
Diffusion-Coefficient and Two-Tanks ModelSetsuo HAYASHI1989 Volume 51 Issue 6 Pages 71-76
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSExperimental data on drying characteristics of Japanese persimmons were analyzed using an exponential model on the presumption that the drying process can be treated as heat-and-mass transfer between single sphere and air. The diffusion coefficient varied with drying conditions, and the drying coefficient was related to the size of persimmons. Hand-rubbing of fruit affected the drying constant.
To mean moisture content (mc) of a whole fruit and mc of secondary surface, a two-tanks model was applied, which was promising to predict mc of secondary surface for both continuous and intermittent drying.View full abstractDownload PDF (740K) -
Decreases of viscosityYouichi SHIBATA, Yoshiaki GOTO, Kensuke AMANO, Kouhei TASAKA, Tsutomu ...1989 Volume 51 Issue 6 Pages 77-81
Published: 1989
Released on J-STAGE: April 30, 2010
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Noboru NOGUCHI, Hideo TERAO1989 Volume 51 Issue 6 Pages 83-88
Published: 1989
Released on J-STAGE: April 30, 2010
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Tatsuya KONISHI, Mitsuhiro HORIO, Seiichi YOSHIDA, Ikuo YAMAKAGE1989 Volume 51 Issue 6 Pages 89-95
Published: 1989
Released on J-STAGE: April 30, 2010
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[in Japanese]1989 Volume 51 Issue 6 Pages 97-101
Published: 1989
Released on J-STAGE: April 30, 2010
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Yoshio NISHIYAMA1989 Volume 51 Issue 6 Pages 103-106
Published: 1989
Released on J-STAGE: April 30, 2010
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Yasumasa KOGA1989 Volume 51 Issue 6 Pages 107-115
Published: 1989
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESS[THAILAND] Rice marketing and processing are made by private parties. Technology employed by custom mills has developed as the result of their competition. Commercial mills, however, are stagnant in the technical development. The reason might be ascribed to the fact that rice merchants are commercial profit-oriented. Since they often work as money-lenders and collect paddy in advantageous terms, they are sometimes hated and prone to be scapegoats on social turmoils. This leads vicious circle to make them concentrate in commercial transaction than for processing. If paddy price were paid to farmers in proportion to the quality, not only farmers' incentives for quality improvement formed but rice merchants' social status also can be established.
[JAPAN] Farmers dehusk and sell brown rice. Since the quality can be judged easily than for paddy, farmers have received proportionally better price to the quality and had an incentive to improve the technology in farming and postharvest processing. Joint operations on postharvest processing and marketing strengthened their solidarity and developed rural industries. Commercialization of rural society promoted education and made farmers prepared to industrial society. Technological deevlopment of postharvest process triggered agricultural mech anization. Rice mills are of specific nature.View full abstractDownload PDF (1787K) -
[in Japanese]1989 Volume 51 Issue 6 Pages 117-121
Published: 1989
Released on J-STAGE: April 30, 2010
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