Structural Study on Moving Magnet Compressor for Stirling Engine
The article describes a structural study on moving magnet compressor for Stirling engine. The performance of Stirling engine is determined by the linear compressor. The article first establishes mathematics models for ordinary linear compressors and moving magnet compressors manufactured for test and analysis, then studies magnetic field distribution of linear moving magnet compressor by CAE, the results show that magnet analysis has an agreement with the measurements. A modified moving magnet compressor prototype is proposed based on the results.
A study on the linear compressor characteristics of the Stirling cryocooler
Abstract The purpose of this study is to analyze the characteristics of the linear compressor for Stirling cryocooler. To ensure high performance and long life of the free piston, free displacer Stirling cryocooler, the operating parameters of the linear compressor should be optimized. The experimental results show the operating frequency of the linear compressor has significant effect to the input power characteristics, and the compressor with higher charging pressure of working fluid has high pressure ratio. For the high performance of the linear compressor, compressor has uniform magnetic force with different stroke, and the optimal operating frequency with respect to the charging pressure.
Professor Penck's Bluff: Geography, Espionage and Hysteria in World War I
Abstract This article considers the image of geography during World War I through a discussion of newspaper controversies about the pre‐war activities of German and British geographers. Early in the war, Sven Hedin and Albrecht Penck, renowned geographers whose achievements had been widely celebrated by the British geographical establishment, were named in the media as enemy spies whose supposedly disinterested scientific inquiries in Britain and the Empire had masked their real intention to pass sensitive information to the German High Command. British geography stood accused of collusion with enemy ‘super spies’. This article examines how Britain's geographical community, represented by the Royal Geographical Society, sought to defend the discipline's patriotic virtue and head off a full‐scale media witch‐hunt. In so doing, the article comments on the media's role in shaping the image of geography and on geography's place in public debates about the sanctity of the national space.