Gas hold-ups were measured in a 240mm dia. and 2400mm high three-columns-in-series reactor of the 2.4ton/day NKK direct coal liquefaction process. All measurements were carried out under high pressure in i) two-phase creosote oil/ hydrogen system at room temperature, ii) two-phase anthracene oil/hydrogen and iii) three-phase Illi-nois No.6 coal slurry/hydrogen systems at high temperature by the following three diffe-rent methods; “gas shut-down”, “neutron attenuation” and “gas purge” techniques.
For system i), the gas hold-up, εG, obtained by the three methods showed no signifi-cant difference and increased with the superficial gas velocity, UG. εG at a given UG in-creased with the pressure up to 12.8MPa and then leveled off with the further pressure in-crease. These variations of εG could possibly be attributed to those of the bubble size. The change of εG with UG for system ii) was found to be equivalent to that for system i), if changes in UG and the gas-liquid equilibrium composition due to evaporation of light anthracene oil fractions to the gas phase were appropriately evaluated. Furthermore, εGS for system iii) agreed reasonably well with those reported for coal liquefaction pilot plants and high pressure bouble column.

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Gas holdups in the PSU coal liquefaction reactor were determined by a differential pressure method under the conditions of 170kg/cm^2G and ambient temperature to 450℃. For all velocities tested, gas holdups in the PSU reactor increased with increasing superficial gas velocity and this slope was approximately constant.

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The limiting ability of oils to build up hydrodynamic lubrication film was investigated using a plate-on cylinder testing apparatus on sliding condition. The oil viscosity entrained into the conjunction zone was estimated by comparing the values of the film thickness and coefficient of friction measured during testing and theoretical ones under oil starvation conditions. There was a critical sliding velocity above which the oil thickness and friction force inversely decreased with increasing the sliding velocity. Below the critical sliding velocity, the oil film thickness and coefficient of friction measured were nearly equal to the theoretical ones. The reduction in oil thickness and friction compared with theoretical ones of the supplied oil resulted from preferentially entraining the lower viscosity components of the supplied oil into the conjunction region.

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Damage to and fracture of dies of cold forward extrusion of a bolt part former was detected by use of a fractal property of acoustic emission (AE) during a practical manufacturing operation. Two conditions of lubrication, with and without vegetable oil, were employed. A fractal dimension m of AE amplitude was used to detect damage to and fracture of the die. The extrusion rate was set to 100 pcs./min. A decrease in m was observed after a certain number of repetitions of extrusion N under both conditions. Under the condition without vegetable oil, the die insert was completely ruptured by N = 2850. The m took a minimum value at N = 2807, and then increased. The progress of the defects on the surface of the workpiece showed good agreement with the change in m. Under the condition with vegetable oil, the die insert was completely ruptured by N = 11000. A decrease in m was observed at N = 9000. A fast overload fracture with a ratchet mark was mainly observed on the fractured surface of the die insert under the condition without vegetable oil. The region of stable crack propagation around the die radius was dominant under the condition of lubrication with vegetable oil.

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Injection of low salinity water yields incremental oil recovery (5-20%) with lower operation cost and less environmental load in comparison with other enhanced oil recovery (EOR) technologies. However, mechanisms how the decrease in salinity of injection water improves oil recovery are controversial because someone gets promising results, but another does not with their specific experimental setting (e.g., different rock and different crude oil). Recently, wettability alteration is supposed to play a key role for improving oil recovery by low salinity water. It is the process that salinity change affects wettability initially evolved in reservoirs by interaction among crude oil-brine (formation water)-minerals. Here in this review, core experiments for low salinity water injection are summarized to specify requirements that low salinity water has promising effects to improve oil recovery. Secondary, I analyze and summarize experiments and theoretical simulations that discuss interactions among crude oil, brine, and minerals depending on salinity (and pH). This aims at looking for a universal view for the interactions existing in reservoirs. Finally, it is demonstrated that the evolution of initial wettability in reservoirs can be divided into two processes; contact of crude oil to a mineral surface mediated by brine and adsorption of oil molecules on the mineral surface. These two processes are significantly related to the requirements of low salinity water injection. Besides, interactions significant in the two processes are specified; disjoining pressure (surface charges of crude oil and minerals) and molecular interactions (e.g., cation bridging, acid-base interactions), respectively. From the view point of crude oil-brine-mineral interaction, it is crucial to investigate oil-molecule-specific / ion-specific / mineral-specific surface charge and molecular interactions for elucidating mechanisms of enhanced oil recovery by low salinity water injection.

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燃料油の低質化に起因する機関の障害を最少限にし, 機関が健全な運転を続行するためには燃料油の前処理機器の果たす役割は極あて大きい.ある意味では, これらがあって初めて船内での低質燃料の使用が可能になっていると言っても過言ではない.
本文は, 遠心式油清浄機, フィルタ, ホモジナイザの代表的処理機器に低質油の議論の基礎となる燃料油の分析技術を加えて, 各分野の専門家の執筆により構成した.

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航空機部品において需要が増加しているチタン合金は，熱伝導率が低いなどの特徴から，加工能率が低く，切削加工技術の改善が求められている．本研究では，ダイヤモンドコーティング工具を用いてチタン合金の断続切削を行い，切削性能を評価した．結果，超硬合金と比較して耐摩耗性，耐欠損性に優れているが，凝着に起因するものと考えられる工具刃先のコーティングの剥離が確認され，切削油剤が剥離寿命に影響することがわかった．

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ころがり-すべり接触状態における焼付きに及ぼす表面あらさの影響を十分な給件のもとで調べた.焼付きに対しては,なじみ運転中の表面の加工硬化,表面膜形成状態が重大な影響を与える.すなわち,あらさが小さい場合には耐焼付性に二面性が存在し,大きい場合には耐焼付性はあらさの増加と共に高くなる.また,表面に絞り出されたフェライト相が酸化されることにより酸化膜が形成され,その酸化膜の形成が転移温度で焼付かないための必要条件である.

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Unlike mild steels, cold rolling of high-strength steels gives rise to various problems, the causes of which are related to the high tensile strength, which is a property of the material, the high degree of work hardening, and the fine-scale composition. Furthermore, these characteristics make it easy to generate slip during the rolling of high-strength steel. In this report, the simulation of this rolling slip and its influence on slip occurrence when changing the conditions of rolling oil, which is the lubrication factor, were investigated. On the basis of these conditions, we developed a rolling oil for high-strength steel with excellent slip resistance.

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If bearings for gear units of railway vehicles are damaged by seizing, parts of the bearings come off and damage the gear and the gear box, which may lead to the leakage of the gear oil and the defective rotation of the wheel sets. Tapered roller bearings are mostly used in the gear units in Japan. The sliding speeds at the contact surface between the roller end and the inner ring flange of the pinion bearings are higher than that of the gear bearings. In the pinion bearings, therefore, seizure may occur by metal-to-metal contact from inadequate lubrication between the roller end and the inner ring flange. In order to prevent seizure of the bearings and to improve the reliability of the gear units, it is important to clarify the causes of the inadequate lubrication and the mechanism developing from inadequate lubrication into seizure of the bearings. In this work, the effects of bearing rotational speeds and loads, gear oil temperatures and flow rates, and endplay (internal clearance of bearings) values on the performance of the bearings have been investigated by using a rotation testing apparatus for pinion bearings. As a result, it has been clarified that the heating value from bearings increase as the oil temperature decreases and as the oil flow rate increases. In addition, it has been found that the endplay value is greatly reduced when the rotational speed of the bearing rapidly accelerates to high speed under conditions where the temperature of the gear oil is relatively low.

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