Characteristics of Piston Cooling Oil Jet and Two-phase Flow in Channel for Internal Combustion Engines

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora

The Effect of the Metal Combinations on Wear and Friction in Ultra-High Vacuum Condition

Many studies on the friction and adhesion phenomena under a high-vacuum condition have been done and being continued steadily since the advanced development followed the improvement of the research method. At present studies many types of metal alloys such as bearing steel, stainless steel and phosphor bronze chosen as the test pieces with a few single metals like nickel and tin. Though in the ultra high vacuum condition a lot experiments have been done on friction phenomena, the wear phenomena have not been enough clarified in such condition because of being in itself complicated. As it is most desirable that the change of the worn surface during wear process can be limited within certain extents, the ultra high-vacuum condition are most suitable to clarify the wear mechanism on which a clear explanation has not been made. The experimental results under such condition can clarify the effect of the compatibility among the material combinations, and of difference of the contact shape, furthermore can make clear also experimentally the larger adhesive force than the ploughing term

Venous velocity of the right femoral vein decreases in the right lateral decubitus position compared to the supine position: a cause of postoperative pulmonary embolism?

The right lateral decubitus position is a risk factor for postoperative pulmonary embolism. We examined postural changes of femoral vein velocity in order to elucidate the mechanism. Thirty patients scheduled for general thoracic surgery were enrolled in this study. The common femoral veins on both sides were examined by color-duplex ultrasound for venous caliber and velocity when the patients were in the right lateral, left lateral, and supine positions. The maximum diameters of the right femoral vein in the right lateral decubitus position and the left femoral vein in the left decubitus position were significantly larger than those in the other positions. The venous velocity of the right femoral vein in the right lateral decubitus position was significantly smaller than that in the supine position, while the velocity of the left femoral vein in the left lateral decubitus position was not significantly decreased. We speculate that the decreased venous velocity of the right femoral vein in the right lateral decubitus position could result in a deep venous thromboembolism in the right leg, making this position a possible risk factor for postoperative pulmonary embolism.</p

On the Surface Cracking and Crack Growth Due to the Oscilated Tangential Force without Macro Slip

The occurance of surface cracking in the contact field without any macro slip has been investigated. The effects of the static normal load and the range of alternating tangential force on the crack initiation and growth have been made clear. It was also shown that the stress field may be useful to estimate the total effects of the applied forces even on the surface cracking and growth

Mapping Indicators of Machinery Utilization Predicted by an Artificial Neural Network

A methodology is presented to generate digital maps containing values of Mechanization Indicators (Mechanization Index and Machinery Energy Ratio), predicted without direct calculation, using a multilayered ANN model. The inputs to the ANN model were simple data obtained from local databases.Complementarily there were processed digital maps related to parameters on land slope, farm size, soil texture, water supply for crop production and distribution of the land productivity potential for the main crops in the region of study.Overlapping among the generated maps assisted to analyze the mechanization conditions in every production unit of the Mexican State of Guanajuato, in order to estimate the intensity and suitability of mechanization as well as to identify which farms in the region would benefit more from machinery use.The developed methodology can facilitate the analysis to prioritize areas for the introduction or replacement of agricultural machinery.It is concluded that the present methodology would be a good tool to assess mechanization sustainability of agricultural activities; this in turn providing policy-makers and planners with tools with which to judge the best use of land in the near future. Planning the intensity and suitability of mechanization using this approach would contribute to optimize the use of inputs from oil sources

Optimal Primitives Acquisition for Nonprehensile Manipulation via Composite Model of Motion and Tactile Force

70377836 (科研費)南山大学運動・力触覚モデルによる非拘束マニピュレーションの最適操り運動プリミティブの獲得 2020～2022年度科学研究費助成事業 (基盤研究 (C) (一般)) 研究成果報告書33917 (科研費)202220K04370 (科研費)research repor

Sheet Dependence on Superconducting Gap in Oxygen-Deficient Iron-based Oxypnictide Superconductors NdFeAs0.85

Photoemission spectroscopy with low-energy tunable photons on oxygen-deficient iron-based oxypnictide superconductors NdFeAsO0.85 (Tc=52K) reveals a distinct photon-energy dependence of the electronic structure near the Fermi level (EF). A clear shift of the leading-edge can be observed in the superconducting states with 9.5 eV photons, while a clear Fermi cutoff with little leading-edge shift can be observed with 6.0 eV photons. The results are indicative of the superconducting gap opening not on the hole-like ones around Gamma (0,0) point but on the electron-like sheets around M(pi,pi) point.Comment: 8 pages, 3 figure