Transactions on GIGAKU
Online ISSN : 2435-5895
Volume 7, Issue 1
Displaying 1-8 of 8 articles from this issue
  • Kyoko Owada, Karen Kurihara, Toru Aoi
    2020 Volume 7 Issue 1 Pages 07001-1-07001-6
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    A soil improvement material including Bacillus subtilis (1 ´ 107/g dry weight) and free-living nematodes (1 ´ 104/10 g wet weight) was developed using biomass resources such as cedar bark, dried sludge, and dehydrated soil. The improvement material (3 kg/m2) was introduced into a test field of Chinese yam, while the soil samples were then collected once a week from the predetermined areas of the farm. In this study, the genetic variations of the free-living nematodes associated with the soil improvement material were investigated. The nucleic acid sequences of the ITS1 and ITS2 regions were compared, resulting in the identification of the nematodes species Cephalobidae sp., mycophagous nematode and Phelenchoides sp. Furthermore, predatory nematodes, Paractinolaimus sp. and Rhyssocolpus, which have been proven to be effective in the control of continuous crop disorders, were observed. The yield of the Chinese yam was evaluated, and it was revealed that it remained the same as when chemical pesticides were used, suggesting that the soil amendment material can inhibit the crop damage similarly to chemical pesticides.
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  • Takahisa Ueno, Kyohei Asami, Junko Ninomiya, Takashi Furukawa, Takashi ...
    2020 Volume 7 Issue 1 Pages 07002-1-07002-9
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    The pulsed electric field method, which is cited as a non-thermal physical sterilization method, enables continuous treatment using a simple protocol. Given that this method causes minimal protein denaturation, it can be used to sterilize eggs, fish, and similar protein-rich food items, if its bactericidal strength and energy efficiency can be improved. In this study, the ability of a pulsed electric field to sterilize Vibrio fischeri was examined. When the current applied to V. fischeri was limited, it was impossible to sterilize the bacteria even when the applied voltage and applied time were increased up to 13 kV and 15 min, respectively. Subsequently, when helium flow was used to increase the current to V. fischeri, sterilization was confirmed at an applied voltage of 13 kV for 5 min or more, and ozone water was detected in the bacterial suspension. Here, we show that sterilization could be achieved due to factors besides heat because applying the voltage at 20 °C or lower facilitated sterilization.
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  • Kazuhide Tanaka, Ichiro Yoshida
    2020 Volume 7 Issue 1 Pages 07003-1-07003-7
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    In electric power stations, precise measurement of the surface roughness is absolutely necessary for reducing the environmental load and ensuring quality and safety. Such precise measurement is a difficult and stressful manual operation because it is performed in uncomfortable environments such as high places and narrow spaces. This puts workers in stressful situations and painful postures. We research and develop a crawler-type robot for precise geometric measurement of the surface roughness to relieve stress and improve the working environment. Our robot uses electromagnets to ensure precise measurement accuracy and to reduce the weight and size. In a previous paper, we presented measurement experiments with our robot, which showed that it reduced the standard deviation of the roughness parameter Ra by one-third to one half. From these results, we considered that the use of the precision measurement unit using electromagnet resulted reduction of measurement variation. Example of factors of improved accuracy is vibration reduction, improved rigidity, resistance of temperature change, reduction of deformation, stability, and so on. In the present study, we focus on vibration and analyzed the vibration reduction effect of our unit in the X, Y, and Z directions with a small orthogonal three-axis accelerometer. The results of the vibration experiments confirm that the vibration is reduced in these directions by our unit.
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  • Keito Mizuhara, Makoto Inoue, Tetsuo Aida, Kazuo Matsuzawa, Naritoshi ...
    2020 Volume 7 Issue 1 Pages 07004-1-07004-7
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    Magnesium is light weight, so has excellent mechanical properties, and application to various field is expected. However, commercial pure magnesium corrodes because included iron, nickel and copper. We need ultra high purity magnesium to use it at long time. In this study, preparation of ultra high purity magnesium sheet by vacuum distillation and extrusion was investigated. Vacuum distillation was performed by 600℃ of raw material temperature and 360℃ of condenser temperature using purity of 99.9 % commercial magnesium ingot. It extrude in 375℃ of temperature and 49 of extrusion ratio using the magnesium deposit obtained vacuum distillation. Magnesium sheet were more than 99.9999 % of purity. As a result of the Electron Back Scatter Diffraction Patterns (EBSD) observation of the extruded material, the orientation of the crystal grains is aligned, it was confirmed that it is a texture structure. The corrosion rate of the magnesium sheet was less than 1mm/y. According to results of tensile test in different direction, 0 °, 45 °and 90 ° to the extrusion direction, as a result of tensile test at three angles, the ultimate tensile strength was no changed, the elongation became smaller as the angle increased.
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  • Kenji Yanagisawa, Ren Goto, Chinatsu Saito, Yuri Gomi, Hiroo Taura
    2020 Volume 7 Issue 1 Pages 07005-1-07005-7
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    Inspired by the water-repellent and the self-cleaning properties of the lotus leaf and the nepenthes pitcher plant in the natural world, artificial super hydrophobic surfaces have generated extensive attention in academia and industry. Hydorophobicity and sliding behavior of water droplet are a very important phenomenon in our daily life as well as in many industrial processes. However, the difference between these two phenomena is not well understood. The surface of the silicone rubber sheet causes the water droplet to be slippery with the presence of VGCF (Vapor Growth Carbon Fiber). However, the assistance of VGCF in decreasing the resistance of water droplet has not been clarified yet. The aim of this research is to examine the amount of VGCF required to make the water droplet on the surface the most slippery by creating a sheet with different amount of VGCF. This study was performed to predict movement of water droplets on surfaces of silicone sheet and was focused on relationship young's modulus on surface and interface resistive forces between water droplets and surfaces.The relationship may help prediction of movement of droplets on surfaces.
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  • Ayumu Inagaki, Daichi Ishii, Toyohisa Asaji, Tsubasa Nakamura, Naoto W ...
    2020 Volume 7 Issue 1 Pages 07006-1-07006-7
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    It is well known that the mainstream turbulence intensity in wind tunnel experiments affects flow transition and separation. To reduce this intensity, wind tunnel straightening conditions have been examined in the past. However, these conditions did not reduce the turbulence intensity of the blowdown wind tunnel in our laboratory, because the turbulence from the dustproofing device at the air inlet of the fan is not straightened, even if it passes through the straightening section of the wind tunnel. In this research, the relationship between the mainstream turbulence intensity and the dustproofing device is investigated. In the experiment, two types of mesh and four types of dustproof felt with different resistance values are installed on the air inlet of the fan. The mainstream velocity and turbulence intensity values are calculated from the fluctuation velocity measured by the hot-wire anemometer at the center of the wind tunnel exit. The mainstream velocity is adjusted by changing the faninverter frequency from 0 to 60 Hz. Although it depends on the air-inlet condition of the fan, the mainstream velocity is approximately 0 to 25 m/s. The mainstream velocity is found to be related to the resistance coefficient of the wire meshes and felts. However, no difference in turbulence intensity due to the resistance coefficient can be observed, and esistance coefficients above a certain level are considered to affect the turbulence intensity. The important point of the wind tunnel inlet conditions is considered to ensure the required inflow rate for the fan, even with the filter attached.
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  • Ryo Sakakibara, Ichiro Yoshida, Yuki Kondo, Kenichi Yamashita
    2020 Volume 7 Issue 1 Pages 07007-1-07007-7
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    Roughness analysis methods for plateau structure surfaces have been proposed in ISO and JIS standards as well as in previous researches. However, these analysis methods cannot calculate the roughness parameters for surfaces with insufficient plateau structures. In the material probability curve (MPC), this problem is caused by the narrow plateau region found in surfaces with insufficient plateau structures. Development of a new roughness analysis method that can analyze surfaces with insufficient plateau structures is indispensable for understanding the wear progress of plateau surfaces as demanded by industry. If these problems related to the plateau surface can be solved, it can contribute to the achievement of improving engine performance and reducing automobile CO2 emissions. Therefore, the purpose of this research is to enable calculation of the roughness parameters for surfaces with insufficient plateau structure. In this research, a new analysis method using the weighted least-squares line (WLSL) was investigated and developed. The proposed method of this research succeeded in calculating the roughness parameters for surfaces with insufficient plateau structures, whose parameters could not be correctly calculated by previous methods.
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  • Gustavo Capilla González, Yashiro D. Cisneros-Reyes, Takaomi Kobayashi
    2020 Volume 7 Issue 1 Pages 07008-1-07008-5
    Published: 2020
    Released on J-STAGE: July 20, 2020
    JOURNAL OPEN ACCESS
    This research work presents a general scheme from an international perspective by analyzing the triple helix generated by the academy-industry-government relationship of two nations with different types of economies and social structures, Mexico and Japan. In recent years, collaboration projects have been extensively encouraged by both countries through the GIGAKU Techno Park under the GIGAKU philosophy. In the presented work, a general description the role of the GIGAKU Techno Park in the development of an emergent economy like Mexico is presented and compared with those developed in Japan. Also, the strategies implemented in both countries to promote the linking between the academy, industry and government identified as the main stakeholders of the Triple Helix model are analyzed. Finally, a crossborder collaboration scheme based on the strengths and opportunities involving the industry, academy and the GIGAKU Techno Park are presented to generate a triple helix model.
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