著者
吉田 肇
出版者
公益社団法人 日本表面真空学会
雑誌
日本表面真空学会学術講演会要旨集 2021年日本表面真空学会学術講演会 (ISSN:24348589)
巻号頁・発行日
pp.1Ep13, 2021 (Released:2021-12-24)

2019年に、真空技術の一般用語の定義を規定したISO規格が38年ぶりに改正された。日本表面真空学会 規格標準化委員会と日本真空工業会 規格標準委員会が合同で組織する規格標準合同検討委員会では、このISO規格の改正に対応するため、JIS Z 8126-1の改正作業を行った。改正されたJISは、2021年9月に発行される。気体の標準状態や高真空の定義など、いくつか重要な改正点があるため紹介する。
著者
吉田 肇 高西 哲朗 根本 哲也
出版者
石油技術協会
雑誌
石油技術協会誌 (ISSN:03709868)
巻号頁・発行日
vol.74, no.5, pp.432-436, 2009-09-01

INPEX Browse Ltd. has drilled 6 wells in the Browse Basin in order to appraise the production permit WA-285P from 2000 through 2004 (at the 1st and 2nd Drilling Campaign). All of wells have encountered stuck pipe problems while drilling the unconsolidated Grebe formation sandstone and they have provided a lot of Non Productive Time (NPT) due to fishing or sidetrack. According to the desk top study of Grebe, which was performed after drilling in 2004, it was concluded that the stuck pipe problems result from the collapse of unconsolidated sand, in other words, such collapse is caused by the absence of an effective filter cake capable of stabilizing the well bore. Eventually, INPEX Browse Ltd. has decided to drill the unconsolidated Grebe formation sandstone by closed circulation system using drilling mud instead of Seawater.<br>In order to achieve this objective, Riserless Mud Return (RMR) system was introduced by AGR (Norwegian Company) before 3rd Drilling Campaign. Through this system, all three (3) wells have been successfully drilled without any hole collapse and no NPT was recorded. That is a major improvement rather than last two (2) drilling campaign and RMR system was demonstrated as one of an effective procedure to drill unconsolidated formation in Browse Basin.
著者
岡崎 航介 吉田 肇 入澤 優磨 櫻庭 隆貴
出版者
海上保安大学校
雑誌
海上保安大学校研究報告. Part 2, 理工学系 = Report of Japan Coast Guard Academy. 海上保安大学校 編 (ISSN:02872951)
巻号頁・発行日
vol.57, no.1, pp.41-47, 2013

Not a few fires in the engine room of ships are caused from the ignition of spilled oil on the hot part of machines such as turbo-chargers, boilers etc. Authors have continued to investigate ignition and combustion phenomenon of oils on the hot surface of a metal plate with various conditions of the surface and many kinds of fuels for understanding of the mechanism of fires in engine rooms. However, it could not be well-considered about flow of the air in the reaction region because of the design of the experimental apparatus, although it is important for the ignition and combustion. In this study. CFD (Computational Fluid Dynamics) calculation using OpenFOAM is introduced for consideration of experimental results of the fuel ignition tests and some simple cases are simulated.
著者
吉田 肇 城 真範 平田 正紘 秋道 斉
出版者
The Vacuum Society of Japan
雑誌
真空 (ISSN:18822398)
巻号頁・発行日
vol.54, no.5, pp.298-306, 2011-05-20
被引用文献数
3

A transmission probability <i>W</i> of gas molecules passing through a vacuum component is usually calculated using the Monte Carlo method. In the calculation, it is generally assumed that gas molecules are introduced to a smooth surface and scatter with cosine low. Since the <i>W</i> is influenced by the shape and/or roughness of the surface in practice, the precise calculation of <i>W</i> requires the inclusion of surface geometry. The conventional Monte Carlo method, however, needs very long time to calculate the <i>W</i> for a cylinder with many corrugations, in other words, rough surface. In this paper, a new method to decrease the time for a calculation with rough surface is described. In the new method, the scattering angle distribution distorted by corrugations is analytically calculated. The distorted distribution is used to determine the scattering angle of the gas molecules at the surface. In the case of a cylinder with the ratio of length to the radius <i>L/r</i> of 5, the ratio of the <i>W</i> with V-shaped corrugations to that without corrugations is 0.77 at minimum. Results of the calculation were obtained by both the new method and the conventional method, and are identical within 0.5%. The time required by the new method was more than 100 times shorter than that by the conventional one.<br>