摘要 :
Airport Cooperative Research Program (ACRP) Synthesis 76: Helicopter Noise Information for Airports and Communities examines the results of a literature review and survey of ten airports to summarize the impact of outreach, helico...
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Airport Cooperative Research Program (ACRP) Synthesis 76: Helicopter Noise Information for Airports and Communities examines the results of a literature review and survey of ten airports to summarize the impact of outreach, helicopter noise management programs, technology, and abatement procedures in managing helicopter noise. The report is geared to assist both airports and communities with addressing helicopter noise and a description of the current state of effective practices for noise management.
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摘要 :
This report presents the results of a study of the spectral content of small arms fire at varying distances. These data can be used in the design of noise mitigating structures for small arms ranges. The one-third octave spectra o...
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This report presents the results of a study of the spectral content of small arms fire at varying distances. These data can be used in the design of noise mitigating structures for small arms ranges. The one-third octave spectra of both the bow wave and muzzle blast, for distances ranging from 162 to 577 m from the source are presented. The data are then used to develop a model that predicts the relative levels of the two components over much larger distances. This leads to the finding that, along the line where the bow wave is maximum, the bow wave predominates over the muzzle blast by a few dB for distances as large as 10 km. In other directions, the muzzle blast predominates.
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摘要 :
Noise level data were gathered for U.S. Army Corps of Engineers (CE) powerhouses including most of the larger powerhouses, in order to determine (1) the nature and extent of excessive noise levels (in excess of hearing conservatio...
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Noise level data were gathered for U.S. Army Corps of Engineers (CE) powerhouses including most of the larger powerhouses, in order to determine (1) the nature and extent of excessive noise levels (in excess of hearing conservation criteria) in CE powerhouses and (2) which noise sources were common to most CE powerhouses. The results indicate numerous areas in CE powerhouses where noise levels are excessive. The general noise sources are the turbines, the generators, and various auxiliary pumps, such as fish pumps or air conditioning chiller pumps. This investigation also determined that the 120 Hz pure tone radiated by the main electrical generators at CE powerhouses may constitute more of a hazard than current hearing conservation standards indicate. (Author)
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