Japanese Journal of Farm Work Research
Online ISSN : 1883-2261
Print ISSN : 0389-1763
ISSN-L : 0389-1763
Volume 33, Issue 3
Displaying 1-4 of 4 articles from this issue
  • Panel Structure and Performance
    Akira SASAO, Mikio IWASAKI
    1998 Volume 33 Issue 3 Pages 133-138
    Published: September 20, 1998
    Released on J-STAGE: February 09, 2010
    JOURNAL FREE ACCESS
    In this study a noise insulating panel was developed using a natural based polymer gel sandwiched and boarded by transparent materials. In addition, a material between the boards of the noise insulating panel was selected and its application to a Welsh onion shelling machine was examined. Results of this study are as follows.
    1) According to the transparency, it became clear that due to the 1.0% density of Gellamgum, the decrease in the transparency was just about 10%. Furthermore, the coefficient of light transmission showed 78.3%-71.7% in the five types of densities (0.25-1.25%) of Gellamgum and effect of the density was small.
    2) According to the noise reduction efficiency, regarding the frequencies of the filtered noise coming through the insulating panel poured with a polymer gel, we can say that the coincidence effect at 315Hz and 3150Hz was significantly fairly reduced. By using Gellamgum, the effect and the noise at high range frequencies of 2kHz to 4kHz were fairly reduced.
    From the measurements conducted, it was clear that Cgllemgum having a noise reduction efficiency, has a high light transmission coefficient. From the economic view point, the ease of handling and manufacturing, Gellamgum gel with 1% density was suitable and it was decided to be used as a stuffing material for the boards of the noise insulating panel.
    3) Using the noise insulating panel, a soundproof cover for the Welsh onion shelling was constructed and was examined in order to reduce the noise.
    Results of the frequency analysis showed that the noise coming from high frequency vibration of Welsh onion shells at frequency of 2.5kHz was reduced by 16.2dB. Moreover, it became clear that using the soundproof cover with high noise reduction efficiency, the transparency was the highest at 75%, and the soundproof cover was able to provide an excellent working environment relating to sense of hearing as well as sense of sight. Gellamgum widely used in food industry, acrylic plate and glue sold at market were used as basic materials for the soundproof cover which could be constructed easily. Therefore, every farmer having a small budget could possibly fabricate a soundproof cover which is pretty easy to use.
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  • Naoki SAKAI, Hisayoshi HAYASHI, Mayumi OYAMA, Hitoshi KONNO, Kazunori ...
    1998 Volume 33 Issue 3 Pages 139-146
    Published: September 20, 1998
    Released on J-STAGE: February 09, 2010
    JOURNAL FREE ACCESS
    We investigated the difference of work performance and crop yield in the two transplanted paddy fields applied minimum tillage (MT) and conventional tillage (CT). The obtained results were as follows.
    Although travel reduction of transplanter in CT was higher than that in MT, transplanting did not effect on qualities of rice seedling in both MT and CT. From the survey on plant growth, there were significant differences in plant length, number of tiller and value of SPAD (Index of chlorophyll content in leaf). Kind of weeds in MT was more than that in CT and quantity of weeds in MT was much than that in CT. There was no clear difference of grain yield between in MT nad in CT.
    From the measurement of soil penetrating resistance, monotonous change was observed in CT, but distinctive change was observed in MT with the lapse of time. There was no clear difference of three phases of soil between in MT and in CT except for some measured values. There was no difference of contents of nitrogen and carbon between in MT and in CT.
    The total required work time in MT was 70% less than that in CT. Finally the sampling numbers of hill required in a survey on grain yield for MT were decided.
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  • Haochun JIN, Naotaka HAYASHI, Shoji MORIIZUMI
    1998 Volume 33 Issue 3 Pages 147-153
    Published: September 20, 1998
    Released on J-STAGE: February 09, 2010
    JOURNAL FREE ACCESS
    The purpose of this study is to establish a new method for the evaluation of workload in terms of heart rate (HR). A box step stress test would be a better alternative to the bicycle-ergonometer test because of its simple components and portability.
    We performed three kinds of tests in order to find the appropriate height and rate of stepping for the step stress test. We recorded the HR with varying the step rate at a constant step height, varying the height at a constant rate, and varying the step height and rate under constant power (the product of step height and rate is constant). The results were as follows:
    1) There was a strong correlation between HR and the physical power of the step stress test. Also, there was a strong correlation between the consumption volume of oxygen (V02) and physical power. The coefficient of correlation, in both cases, was larger than 0.99 in all subjects.
    2) Sixteen subjects out of 18 tested, showed the minimum HR and V02 when the step height was 30cm and the step rate was 20 steps/min. These results show that 30cm and 20 steps/min is the most suitable height and speed for average-sized individuals.
    3) The HR for the step stress test at 30cm×20 steps/min was 120 to 150 beats/min. Since the HR was greater than 110 beats/min, we believe that the HR was not affected by mental stress.
    4) The above results show that the step stress test can be used for the bicycle-ergonometer test to determine power. The test with 30cm height at 20 steps/min was found as the most appropriate step stress test for subjects 150-180cm tall.
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  • Shinjiro KANAZAWA
    1998 Volume 33 Issue 3 Pages 155-169
    Published: September 20, 1998
    Released on J-STAGE: February 09, 2010
    JOURNAL FREE ACCESS
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