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Measurement of sound absorption in the airThe large temperature gradient in each section of the resonance tube resulting from the liquid nitrogen coolant necessitated a design modification to the cooling system. A timer and four solenoid valves were installed so that the coolant flow can be reversed periodically. The hardware and software for controlling the analog to digital converter and conversion rate were completed, and the system is operational. A duty cycle control circit was implemented so that on the sixteenth conversion a relay shuts off the vibration exciter used to generate the sound wave. Thus the starting point of each decay curve is exactly known. This information is necessary for evaluating the g digital decay information. The data acquisition and digital decay evaluation programs are described.
Document ID
19820005956
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Meredith, R.
(Old Dominion Univ. Norfolk, VA, United States)
Badavi, F.
(Old Dominion Univ. Norfolk, VA, United States)
Becher, J.
(Old Dominion Univ. Norfolk, VA, United States)
Date Acquired
August 10, 2013
Publication Date
August 1, 1981
Publication Information
Publication: Old Dominion Univ. Propagation of Sound Through the Earth's Atmosphere
Subject Category
Acoustics
Accession Number
82N13829
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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