Volume 4, Number 1, March, 1996 - Noise News International

CONTROLThe illustrations in this feature article appearedfirst in a book published in Swedishby Arbetarskyddsfonden, the Swedish Work Environment Fund. The Fund was establishedby national legislation in Sweden to conduct research and education in the fieldofwork environment improvement, and is jointly operated by Swedish employers andlabor unions.The book was translated into English and disseminated as a guidefor workers andemployers by the U.S. Department ofLabor. It has also been translated into otherlanguages, notably Finnish and Danish, but its overall circulation has been limited.The illustrations are being republished here to give them wider circulation, particularlyamong noise control engineers.The formulation ofthe principles, the choice ofexamples and the preparation ofpreliminary sketches was the workofStig Ingemansson. The original illustrations wereprepared by Claes Folkesson.The principles and practice ofnoise control are presented in eight sections:PrinciplesandPractice(Part 8)A. Sound behaviorB. Soundfrom vibrating platesC. Sound production in air or gasesD. Sound production in flowing liquidsE. Sound propagation indoorsF. Sound propagation in ductsG. Soundfrom vibrating machinesH. Sound reduction by enclosure walls.The text of the U.S. Department of Labor translation has been checked andimproved by the author. The illustrations are being published serially in NoiseINewsInternational. Illustrations A1 throughA4 appeared in NNI, Vol 2 No.2, 1994 June,pages 108-115. Illustrations A5 through A8 appeared in NNI, Vol 2. No.3, 1994September, pages 185-193. Illustrations B1 through B3 appeared in NNI, Vol. 2, No.4, 1994 December, pages 244-249. Illustrations B4 through B6 appeared in NNI, Vol.3, No.1, 1995 March, pages 46-51.Illustrations B7 through C2appeared in NNI, Vol. Stig Ingemansson3, No.2, 1995 June, pages 120-127. Illustrations C3 through C5 appeared in NNI,Vol. 3, No.3, 1995 September, pages 178-183. Illustrations C6 through D1 appearedin NNI, Vol. 3, No.4, 1995 December, pages 238 - 243. Illustrations appearing in thisissue are the following:D2. Large and rapid changes in pressure produce "cavitation" noiseE1. Sound sources should not be placed near cornersE2. Thick, porous layers absorb both high and low frequency sound.These illustrations should assist engineers in explaining to others the fundamentalprinciples ofnoise control. -Ed.Stig Ingemansson is the founder ofSwedensleading consulting firm in acoustics.He was a lecturer in acoustics for many years at Chalmers University ofTechnology,Gothenburg, Sweden, and recently receivedan honorary doctoratefrom the university.His address is: Stig N.? Ingemansson, DNV Ingemansson AB, Gullbergs Strandgata6, Box 276, S-40 124 Gothenburg, Sweden.1996 March NoiselNews International 39