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Human explorers of planetary surfaces would benefit greatly from a spacesuit design that facilitates locomotion. To aid in the development of such an extravehicular activity suit, a design effort incorporating the concept of mechanical counter pressure (MCP) was undertaken. Three-dimensional laser scanning of the human body was used to identify the main effects of knee flexion angle on the size and shape of the leg. This laser scanning quantified the changes in shape that must be supported by an MCP garment and the tension that must be developed to produce even MCP. Evaluation of a hybrid-MCP concept using inextensible materials demonstrated strong agreement between experimental data and a mathematical model with rigid cylinder geometry. Testing of a form-fitting garment on the right lower leg of a subject demonstrated successful pressure production. Further research is required to evaluate how evenly pressure can be distributed using the hybrid-MCP concept.

The authors worked in the Engine Department at Nakajima Aircraft Co. from 1936 to 1945. Nakagawa was in the Engine Design Department, where he was involved in designing the air-cooled, radial double-row 14-cylinder 1,100 hp Sakae Model 20 engine and the radial 18-cylinder 1,800 - 2,000 hp Homare engine. Mizutani was a field engineer for these two engines and other engines. During that period we gained much experience in fuel and lubrication systems. Before the authors joined Nakajima, the company's engine development team had already developed a carburetor-based fueling system, which was subsequently used in all Nakajima engines. From 1941 on, all newly designed engines had to use 87-92 motor octane fuel by order of the Army and Navy. It was a very difficult task to change the engine specifications to meet this requirement, particularly for the Homare engine, which was initially designed for 100-octane fuel. The authors explain various steps taken to overcome this difficulty.

In an engine system, the piston pin is subjected to high loading and severe lubrication conditions, and pin seizures still occur during new engine development. A better understanding of the lubricating oil behavior and the dynamics of the piston pin could lead to cost- effective solutions to mitigate these problems. However, research in this area is still limited due to the complexity of the lubrication and the pin dynamics. In this work, a numerical model that considers structure deformation and oil cavitation was developed to investigate the lubrication and dynamics of the piston pin. The model combines multi-body dynamics and elasto-hydrodynamic lubrication. A routine was established for generating and processing compliance matrices and further optimized to reduce computation time and improve the convergence of the equations. A simple built-in wear model was used to modify the pin bore and small end profiles based on the asperity contact pressures.