DIN 108 T.4-1976 幻灯放映机和幻灯片.电视用5×5幻灯片放映的画面尺寸

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下一篇: DIN 2137 T.2-1976 办公技术和数据技术.字母数字键盘.文件和数据加工用的德文键盘.字符的分布

Product Code:SAE AS4831
Title:Software Interfaces for Ground-Based Monitoring Systems
Issuing Committee:E-32 Aerospace Propulsion Systems Health Management
Scope:To establish a specification for software input and output interfaces for condition monitoring and performance programs used to monitor equipment from multiple manufacturers.The purpose of standardizing these interfaces is to improve operational flexibility and efficiency of monitoring systems as an aid to cost effectiveness (e.g., easier implementation).Product Code:SAE AIR1672
Title:Practical Methods to Obtain Free-Field Sound Pressure Levels From Acoustical Measurements Over Ground Surfaces
Issuing Committee:A-21 Aircraft Noise Measure Noise Aviation Emission Modeling
Scope: Acquisition of free-field data is of practical significance in the field of aeronautical acoustics. The need for free-field data includes (but is not restricted to) the following: comparison of acoustical data obtained from the same engine under various measurement conditions; comparison of the results obtained from models with those from an engine on a test stand; comparison of noise measurements made on the same engine under static and in-flight conditions; design of test facilities; standardization of techniques for 'in situ' acoustical measurements; spectral decomposition to isolate the contribution of different sources to the total noise; and prediction of aircraft noise on the basis of methods which, generally, provide free-field data. There is an increasing tendency to test full-scale engine components and scale models in anechoic test facilities that provide free-field conditions. This AIR complements this work by identifying those methods in current use which provide free-field acoustic data for measurements on engines under static conditions in the presence of a ground surface. Separate Appendices to this AIR describe different methods for noise measurement in the field that conform with the state-of-the-art to a certain extent. That is, each method has generally been systematically used by at least oe free-field conditions. This AIR complements this work by identifying those methods in current use which provide free-field acoustic data for measurements on engines under static conditions in the presence of a ground surface. Separate Appendices to this AIR describe different methods for noise measurement in the field that conform with the state-of-the-art to a certain extent. That is, each method has generally been systematically used by at least one organization and has been substantiated by data obtained from at least one test site.ne organization and has been substantiated by data obtained from at least one test site.