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Noise - 2,325 entries found

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1973

CIS 74-114 Atherley G.R.C.
Noise-induced hearing loss: The energy principle for recurrent impact noise and noise exposure close to the recommended limits.
Discusses the approach needed to confirm D.W. Robinson's energy principle as applying to noise exposure. Data are presented supporting the energy principle for exposure to recurrent impact noise and exposure corresponding closely to 2 recommended exposure limits: the British Occupational Hygiene Society's 1971 hygiene standard for wide-band noise (CIS 198-1972, Bik Qez (627)) specifying a maximum noise immission level for a working lifetime, and the U.K. Department of Employment's 1972 code of practice for reducing the exposure of employed persons to noise (CIS 2682-1972, Bik Qay Sgw (627)). Data from a previously published study of drop forgers (CIS 1921-1971, Bik Qay) are used to exemplify the method used. A discussion between the author and various experts is briefly reported.
Annals of Occupational Hygiene, Aug. 1973, Vol.16, No.2, p.183-194. Illus. 14 ref.

CIS 74-112 Dryden S.L., Judd S.H.
Must your new plant be too noisy?
It is estimated that noise control measures adopted at the design stage are 2 or 3 times less expensive than measures taken in existing plants. Methods of achieving acceptable noise levels in a crude oil unit are reviewed, typical design features are tabulated and means of checking and enforcing contractors' compliance with equipment specifications are proposed. The second part of the article deals with the protection of the community against plant noise.
American Industrial Hygiene Association Journal, June 1973, Vol.34, No.6, p.241-251. Illus.

CIS 74-111 Damongeot A., Lataye R., Tisserand M., Krawsky G.
Efficiency and comfort of personal hearing protectors
Efficacité et confort des protecteurs individuels contre le bruit. [in French]
Results of tests carried out (for determining both comfort and efficiency) by the French National Research and Safety Institute (INRS) on 60 commercial models, and criteria for the choice of ear protectors in terms of noise characteristics and environmental requirements (protection against impact, speech communication). A selection of 12 ear protectors (1 helmet, 5 earmuffs, 6 earplugs) is presented in the form of diagrammatic data sheets.
Travail et sécurité, Sep. 1973, No.9, p.434-450. Illus. 2 ref.

CIS 74-110 Lerner R.M., Carstensen E.L., Dunn F.
Frequency dependence of thresholds for ultrasonic production of thermal lesions in tissue.
A model is presented to explain the apparent lack of frequency dependence of the ultrasonic intensity threshold for producing lesions in mammalian brain tissue. Maximum temperature developed in the lesion volume for a given pulse duration is determined by the absorption coefficient (linearly dependent on frequency) and the sharpness of the acoustic beam (inversely proportional to frequency). Temperature calculations related to diffusion, frequency dependence for the beam geometry and the absorption coefficient are used to derive curves for threshold dosages beyond 1 s exposure. All are nearly frequency independent, suggesting that thermal processes may be predominant for such exposures.
Journal of the Acoustical Society of America, Aug. 1973, Vol.54, No.2, p.504-506. Illus. 9 ref.

CIS 74-109 Kubík Š., Vladár M.
Experimental study of temporary shift of hearing threshold due to continuous noise
Experimentálna štúdia o dočasnom posune sluchového prahu z kontinuálneho zvuku [in Slovak]
42 subjects (mostly students between 16 and 26 years of age) were exposed to noise for several periods of 4 h each. Sound pressure was made to vary between 75 and 100 dB, and frequency between 250 and 10,000 Hz (by stages of 500, 1,000, 2,000 and 4,000 Hz). The hearing threshold was determined before exposure and after 2 and 4 h of exposure. Sound pressure of 75 dB or less does not produce any abnormal threshold shift, whereas significant shifts are observed at 90 dB and over. The most significant variations were observed in the frequency band 4,000-6,000 Hz (according to sound pressure) and the smallest variations between 250 and 500 Hz.
Pracovní lékařství, Jan. 1973, Vol.25, No.1, p.5-10. Illus. 8 ref.

CIS 74-108 Navas E.P., Kotalik B.D.
On Helmholtz resonator effects in the discharge system of a two-cylinder compressor.
Cylinder interaction by way of discharge cavities and collecting plenums may be simulated on a computer by considering the discharge system as a variable Helmholtz resonator. Valve dynamics equations and Helmholtz resonator type equations were derived and solved simultaneously. Measured and computed discharge cavity pressures showed good agreement. The excitation of the asymmetric mode of discharge gas oscillation of the prototype compressor is discussed, and ways of suppressing it are considered.
Journal of Sound and Vibration, 8 Oct. 1973, Vol.30, No.3, p.263-277. Illus. 18 ref.

CIS 74-107 Carter N.L., Dunlop J.I.
The effects of rise time and repetition rate on the thresholds for acoustic transients.
The effect on audibility thresholds of variations in rise time and repetition rate of acoustic transients 1 ms in duration was studied. It was found that the threshold was lowered (and thus improved) by an increase in rise time (despite previous findings that the loudness of transients increases as rise time is shortened) and that the threshold decreases with increases in the repetition rate. The results are interpreted in terms of Zwislocki's theory of temporal integration and a critical bandwidth that does not alter with the duration of the sound.
Journal of Sound and Vibration, 8 Oct. 1973, Vol.30, No.3, p.359-366. Illus. 11 ref.

CIS 74-106 Cummings A.
End-plate vibration in exhaust silencer chambers.
An examination of the behaviour and effects of yielding silencer endplates. A theoretical model is proposed and compared with the measured behaviour of an actual end-plate. It is concluded that the behaviour of silencer end-plates can be accurately predicted; a theoretical model may thus serve as a quick check of silencer design.
Journal of Sound and Vibration, 8 Oct. 1973, Vol.30, No.3, p.367-372. Illus. 5 ref.

CIS 74-104 Quevauviller A., Levrier-Pottier J.
Physiopathological effects of noise
Effets physio-pathologiques du bruit. [in French]
Specific action of noise on the auditory function (masking effect, auditory fatigue, acoustic trauma), effect on the central nervous system, effect on the major functions: respiratory, renal, digestive and endocrine systems. Cellular and physiological changes, biological repercussions.
Revue de la sécurité, June 1973, Vol.9, No.92, p.32-39. 77 ref.

CIS 74-103 Acoustics - Guide to the measurement of airborne acoustical noise and evaluation of its effects on man.
Acoustique - Guide pour le mesurage du bruit et l'évaluation de ses effets sur l'homme. [in French]
Classification of noise problems and of different kinds of noise; physical measurement of noise (quantities to be measured and choice of method; survey method, engineering method and precision method; presentation of results); evaluation of the effects of noise on man (quantities to be determined, methods of determination, methods for relating physical properties of noise to an approximate measure of subjective effects: loudness level and loudness, perceived noise and noisiness, permissible noise exposures for hearing conservation, annoyance caused by noise, speech interference).
International Standard ISO 2204-1973(E), International Organisation for Standardization, Case postale 56, 1211 Genève 20, Switzerland, 1 May 1973. 7p. 23 ref. Price: SF.13.00.

CIS 74-102 Jansen G.
Threshold limit values and their psycho-physiological significance in noise control
Grenz- und Richtwerte in der Lärmbekämpfung und ihr psycho-physiologischer Aussagewert [in German]
Article discussing threshold limit values for noise established by examination of the ear and the neurovegetative system, followed by an account of recent findings of research on the psychosomatic effects of noise. These studies show that above 90 dB(A), effects recorded can no longer be considered as normal reactions to noise stimuli. This leads to the conclusion that health is endangered between 90 and 100 dB. The author proposes the substitution of a "threshold limit area" for "threshold limit value".
Kampf dem Lärm, June 1973, Vol.20, No.3, p.71-78. Illus. 9 ref.

CIS 74-101 Constructional noise - A survey of noise on building sites.
Le bruit dans le bâtiment et les travaux publics - Une étude du bruit dans les chantiers. [in French]
A review of basic data on the nature and measurement of noise is followed by an inventory of some 30 sources of construction equipment noise including: asphalting machines, trucks, loaders, compressors, excavators, mobile cranes, percussion drills and drilling hammers, bolt guns, rollers, circular saws, tractors, internal concrete vibrators, etc. The causes of noise, sound level, sound frequency and appropriate measures are given for each machine or type of equipment. Suggestions on noise limitation are followed by a section on ear protectors. Attenuation curves at different frequencies for 8 earplugs and 56 earmuffs are presented; all of these protectors have been approved by the Swedish Industrial Safety Board. Protectors lose their capacity for attenuation - particularly in the low-frequency region - if they do not fit tightly around the ear or in the auditory canal.
Bygghälsan, Fack, 100 41 Stockholm 26, Sweden, Apr. 1973. 72p. Illus. 9 ref.

1972

CIS 76-99 Liénard P., François P.
Industrial acoustics - Basic principles and metrology
Acoustique industrielle - Eléments fondamentaux et métrologie. [in French]
Comprehensive reference work sponsored by the Groupement des Acousticiens de langue française, covering the following subjects: basic elements of physical acoustics; sound transmission and absorption; basic elements of physiological acoustics (evaluation of annoyance due to permanent noise, limits of hearing loss hazard, acoustic trauma, influence of vibration on man, personal protection, etc.); noise measuring and analysis equipment; sound measurement techniques; noise control and working methods (personnel requiring protection, noise abatement methods, preventive action, laws governing sound emission by machinery (noise of mechanical, electrical, aerodynamic, hydraulic origin, etc.). Alphabetical index.
Editions Masson et Cie, 20 Boulevard Saint-Germain, Paris, France, 1972. 285p. Illus. 212 ref. Price: FF.46.00.

CIS 75-1580 Judd S.H.
Noise abatement in existing refineries
L'atténuation du bruit dans les raffineries déjà construites. [in French]
Translation of: Noise abatement in existing refineries. American Petroleum Institute, Washington, USA, 1970, Vol.50, p.125-146. Illus. 4 ref. Communication made to the 35th Annual Meeting of the Refinery Division of the American Petroleum Institute (13-15 May 1970, Houston, USA). The author describes the 4 successive stages of a noise abatement programme: establishment of noise limitation criteria; measurement of noise levels and comparison with the criteria; planning, construction and installation of noise abatement equipment; evaluation of results obtained and possible subsequent correction of procedures. Individual sources of noise (heaters, motors, coolers, compressors, machinery, etc.) and corresponding noise damping methods are tabulated. Another table indicates sources of noise and recommended abatement levels in a fluid-catalyser cracking plant. The results of measurements made before and after modification of the plant are given, illustrated by numerous diagrams.
Traduction INRS 112 B-72, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, 1972. 30p. Illus. 4 ref.

CIS 75-693 Noise in weaving sheds: a short survey.
This note reproduces a report of a survey carried out to compare the sound level and hazard to hearing in these sheds among different types of loom, commenting on measures which can be taken to reduce the hazard. The sound level produced by different types of loom, range of sound pressure levels, increase of sound level with loom speed, and relation between noise exposure and hearing level at 60 years of age are illustrated graphically. Other sections are devoted to: noise reduction by improvement in loom design; effect of weaving shed construction on sound level; hearing loss and damage risk criteria; hearing protectors; recommendations. Tabulated data on over-all sound levels in mills, data on measurement of noise (sound pressure level, frequency, weighted sound level, octave band sound pressure level), and notes on types of shuttleless weaving machines are appended.
Technical Data Note 31, H.M. Factory Inspectorate, Department of Employment, London. H.M. Stationery Office, P.O. Box 569, London S.E.1, United Kingdom, no date. 11p. Illus. 17 ref. Gratis.

CIS 75-375 Thien G.E.
Diesel engine noise - Its origin and means of reducing it
Le bruit des moteurs diesel - Origines et moyens de l'atténuer. [in French]
French translation of: Das Dieselmotorengeräusch - Entstehung und möglichkeiten zu seiner Verminderung. Lärmbekämpfung, Baden-Baden, Germany (Fed.Rep.), 1971, Vol.15, No.5, p.111-115. Illus. 12 ref. Engine noise is produced, on the one hand, by variations in pressure and the aerodynamic phenomena occurring in the exhaust nozzles and cooling fans, and, on the other, by vibrations at the surface of the motor itself or of rigidly-connected parts. Details are given of the manner in which noise is produced by motors; noise-suppression measures are considered. The author draws particular attention to noise transmission via the outer walls of the motor and to methods of reducing its intensity: antivibration mountings; local reinforcement; enclosure.
Translation INRS 151 B-72, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, 1972. 17p. Illus. 12 ref.

CIS 75-66 Valčíc I.
Noise and its harmful effects
Buka i njena štetna dejstva [in Serbocroatian]
A review of present knowledge on noise and its effects: physics of noise and sound; physiology of hearing; noise measurement and analysis; hearing damage risk criteria; noise-induced hearing loss; audiometry; criteria for the assessment of work capacity in the event of noise-induced hearing loss; extra-auditory effects of noise (on the central nervous system, and on heart rate and cardiac activity); protection against the harmful effects of noise (principles of collective and personal protection); biological effects of ultrasound and infrasound.
Institut jugoslovenske i inostrane dokumentacije zaštite na radu, Ulica Stanka Paunovića 17/1, Niš, Yugoslavia, 1972. 182p. Illus. 94 ref. Price: Din.70.00.

CIS 74-1009 Sharland I.
Woods practical guide to noise control.
Keeping the mathematics to a minimum, the author sets out the principles of sound attenuation, with major emphasis on the measurement and control of noise in ventilating systems. Chapters deal with the fundamental concepts of noise physics and hearing, the measurement of acoustic properties, the principles of noise level calculation, the calculation of noise in ventilating systems, the principles of noise control, and examples of noise control.
Woods of Colchester Ltd., Tufnell Way, Colchester CO4 5AR, United Kingdom, 1972. 208p. Illus. 35 ref. Price: £2.00.

CIS 74-1008 Peterson A.P.G., Gross E.E.
Handbook of noise measurement.
A new chapter on hearing conservation has been added to this well-known handbook, reflecting the respective provisions of the Occupational Safety and Health Act of 1970. The increased availability and use of more sophisticated noise measurement systems has led to a separate chapter on noise analysis. The other chapters have been revised and deal with the following aspects of noise and vibration: basic physics, effects and acceptable limits, measurement techniques and instrumentation, noise and vibration control. Some examples of handling industrial noise problems are given. Appendices contain decibel and loudness conversion tables, vibration conversion charts, definitions, pertinent standards and journals, a compilation of hearing loss statutes in the USA and Canada, and a measuring instruments catalogue.
General Radio Company, 300 Baker Avenue, Concord, Massachusetts 01742, USA, 7th edition, 1972. 322p. Illus. 400 ref. Price: US-$7.50.

CIS 74-993 Rainey J.T., Neville D.G.
Sound field visualization technique.
A colour photographic technique for visualising sound fields in both reverberant and free-field spaces is described. It uses a microphone and a number of coloured bulbs. When traversing through the sound field, the microphone signal switches the lights on and off at voltage levels corresponding to specific sound pressure levels, and a camera with a long exposure time is used to record the colour patterns. The resulting photographs and a schematic test set-up are reproduced. By this method, relatively complex acoustical analyses may be performed with a simple equipment. Further development is necessary to apply the technique to noise source location and source order determination for large pieces of machinery.
Sound and Vibration, Dec. 1972, Vol.6, No.12, p.10-14. Illus. 2 ref.

CIS 74-699 Becker R.J.
How to quiet hydraulic systems and components
Comment diminuer le bruit des systèmes et des composants hydrauliques. [in French]
French translation of: "How to quiet hydraulic systems and components", Hydraulics and pneumatics, Cleveland, USA, 1971, Vo.24, No.4, p.122-132. Illus. 5 ref. Type of noise emitted (low frequency noise and large band noise) and noise perceived. Measures proposed to reduce the noise of pumps include regulating the compression rate and modification of power, pressure and temperature. Accidental intake of air in the system (particularly air dissolved in the hydraulic fluid) may also produce noise by bubble formation.
INRS Translation 51 B-72, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, 1972. 14p. Illus. 5 ref.

CIS 74-689 Sharland I.J.
Noise control in air conditioning systems
Lutte contre le bruit des réseaux de conditionnement d'air. [in French]
French translation of: "Noise control in air conditioning systems", Heating and Ventilating Engineer, London, United Kingdom, Aug. 1971, Vol.45, No.529, p.57-63. Illus. This article points out some characteristic details of noise control and indicates the areas where it can be most effective: selection of air-conditioning system, fan dimensions and rotating speed; geometric characteristics of duct system (straight ducts, elbows, connectors, intakes and outlets). Importance of anti-drumming coating. The noise level due to secondary factors (solid obstacle placed in airflow) should not exceed the noise level caused by the principal factor. Special problems in connection with grids and diffusers. Secondary modes of transmission of fan noise and preventive methods.
Translation INRS 76 B-72, Institut national de recherche et de sécurité, 30 rue Olivier-Noyer, 75680 Paris Cedex 14, France, 1972. 19p. Illus.

CIS 74-400 Maling G.C., Lang W.W.
Single-number noise rating for one-third octave band sound power levels.
Although several methods are available for converting the band-pressure spectrum of a noise into a single-number rating, there are but few methods for converting a band-power spectrum into a single-number rating since the relationship between sound power and sound pressure depends on distance from source, absorption characteristics, etc. A study was carried out to investigate the relationship between the Air-Conditioning and Refrigeration Institute (ARI) sound rating number (SRN) and perceived noise level (PNL). It was found that if the ARI rating method is modified slightly, a direct correspondence can be established between the SRN of a band-power spectrum and the PNL of a band-pressure spectrum whose band levels are 20 dB lower in value. To differentiate between a rating based on sound power and a rating based on sound pressure, a single number called the power level rating (LPR), expressed in units of pressure rating decibels (PRdB), is proposed.
Journal of the Acoustical Society of America, Sep. 1972, Vol.52, No.3 (Part 1), p.720-724. Illus. 7 ref.

CIS 74-398 Hunter-Duvar I.M., Elliott D.N.
Effects of intense auditory stimulation: Hearing losses and inner ear changes in the squirrel monkey.
In order to study theories of the relationship between hearing loss and hair cell damage in the organ of Corti, squirrel monkeys were exposed to pure-tone noise at intensities (120 dB) and durations (25 min - 12 h) sufficient to produce repeated temporary threshold shifts (TTS) of 15-25 dB in half the group and permanent threshold shifts (PTS) of 10-20 dB in the remainder. The animals were sacrificed, and the effects of noise exposure on hair cells was determined by surface preparation techniques and phase microscopy. The organ of Corti was examined over its whole length and the number of missing and visibly damaged hair cells along a specific length of the inner and outer rows was determined. There was no clear evidence of cell damage due to exposure. It is concluded that exposure to pure-tone noise sufficient to produce PTS of 10-20 dB does not necessarily produce anatomical injuries in the organ of Corti that are detectable by phase microscopy.
Journal of the Acoustical Society of America, Oct. 1972, Vol.52, No.4 (Part 2), p.1181-1192. Illus. 33 ref.

CIS 74-388 Crocker M.J., Hamilton J.F.
Machine isolation for noise reduction.
Paper presented to the Purdue Noise Control Conference (Lafayette, USA) in July 1971. A simple model is used to illustrate the main characteristics of a machine-suspension system and to discuss the measures which may result in a reduction of the noise generated by the machine. 3 examples are given of the use of vibration isolators in actual practice, the selection of isolating material and the mounting of isolators.
Noise and vibration control engineering. Ray W. Herrick Laboratories, School of Mechanical Engineering, Purdue University, Lafayette, Indiana 47907, USA, 1972, p.203-208. Illus. 13 ref.

CIS 74-386 Burton D.J., Rivera R.O., Butler G.J., McCay F.V.
The evaluation and control of noise produced by a front-end loader mining machine.
Paper presented to the Purdue Noise Control Conference (Lafayette, USA) in July 1971. Description and results of laboratory measurements carried out to determine the noise levels produced by a front-end loading machine and to identify the major contributing elements. Noise levels at the operator's station (up to 100 dBA) were reduced (to 91 dBA) by developing a special exhaust muffler. Vibration measurements were also made on the engine in order to locate sound-producing surfaces.
Noise and vibration control engineering. Ray W. Herrick Laboratories, School of Mechanical Engineering, Purdue University, Lafayette, Indiana 47907, USA, 1972, p.157-162. Illus. 5 ref.

CIS 74-385 Tseo G.G.
Estimating the performance of wall structures used for controlling machinery noise.
Paper presented to the Purdue Noise Control Conference (Lafayette, USA) in July 1971. A mathematical analysis of the linear propagation of sound waves through simple and multiple walls with different front layers leads to an evaluation of the performance of various wall structures, which is illustrated diagrammatically. Several wall structures are considered, and the results compared. It is shown that the front layer does not influence noise reduction and can therefore be dispensed with acoustically. There is an optimal thickness for the acoustical material selected to provide maximal noise absorption.
Noise and vibration control engineering. Ray W. Herrick Laboratories, School of Mechanical Engineering, Purdue University, Lafayette, Indiana 47907, USA, 1972, p.115-122. Illus. 4 ref.

CIS 74-384 Crocker M.J.
Noise and vibration control engineering.
Proceedings of the Purdue Noise Control Conference held at Purdue University, (Lafayette, USA) on 14-16 July 1971. The conference consisted of 9 sessions, 5 of which are of special interest to industrial hygienists and design engineers: machinery noise (8 papers); industrial noise criteria and control (7 papers); vibration control and biodynamics (8 papers); noise and vibration control (9 papers); noise in buildings (10 papers). The papers are reproduced in full, and the volume is supplemented by an extensive bibliography listing all the references given in the papers.
Ray W. Herrick Laboratories, School of Mechanical Engineering, Purdue University, Lafayette, Indiana 47907, USA, 1972. 594 p. Illus. 600 ref. Price: US-$16.50.

CIS 74-380 Gruhl S.
Studies on primary noise reduction on mechanical power presses by use of taper-ground cutting tools
Untersuchungen zur primären Lärmminderung an mechanischen Pressen bei Einsatz schräg angeschliffener Schneidwerkzeuge [in German]
The noise levels to which press operators are exposed at their workstations are to a large extent determined by the cutting impact that occurs when stock is sheared off from the workpiece. It is possible to reduce this cutting impact by the use of taper-ground cutting tools. Systematic studies of cutting tools have resulted in the formulation of general rules for the selection of an acoustically and technologically optimal grinding angle. The noise level reduction attainable is around 10 dB(A).
Informationen für Arbeitsschutz und Arbeitshygiene, 1972, Vol.8, No.4, p.112-117. Illus. 6 ref.

CIS 74-105 Schlegel H., Probst R.
Systematic testing of workers exposed to noise
Reihenuntersuchungen bei Lärmarbeitern [in German]
Part 1 gives an account of the need for and use of "audiomobiles", the means used by the Swiss National Accident Insurance Institute to apply audiometric tests and questionnaires to noise-exposed workers without too great a disruption of production. One "audiomobile" can test 10,000 subjects per year. Part 2 presents the overall concept of systematic examinations of noise-exposed workers from an otological viewpoint in the Institute's hearing conservation programme.
Zeitschrift für Unfallmedizin und Berufskrankheiten - Revue des accidents du travail et des maladies professionnelles, 1972, Vol.65, No.4, p.244-264. Illus. 3 ref.

CIS 73-145 Fuhrmann N.
Dust and noise control on crushers and grinding mills
Staub- und Lärmbekämpfung in der Zerkleinerungstechnik [in German]
Explanation of the basic processes (crushing, milling, grinding, etc.) is followed by consideration of noise and dust control on crushing and grinding machines. Although dust control no longer presents any problems, noise control on these machines is still at the infant stage. Mechanical and structural measures are proposed.
Sicher ist Sicher, June 1972, Vol.23, No.6, p.284-290. Illus. 29 ref.

CIS 72-2637 Okada A, et al.
Temporary hearing loss induced by noise and vibration
5 audiometrically normal subjects were exposed to (1) steady-state noise (101dB), (2) vibration (2 to 20Hz at 100 to 1000cm/s2), and (3) noise plus vibration. The main experimental conclusions were that exposure to vibration of 5Hz and 500cm/s2 (5Hz being the resonance frequency of the human body) produces a significant temporary threshold shift, and that hearing loss from noise may under certain circumstances be increased by simultaneous exposure to vibration.
Journal of the Acoustical Society of America, Apr. 1972, Vol.51, No.4 (Part 2), p.1240-1248. Illus. 16 ref.

CIS 72-2603 Warner H.D., Heimstra N.W.
Effects of noise intensity on visual target-detection performance
The effect of 4 levels of continuous white noise (0, 80, 90 and 100dB) on visual target-detection performance was investigated in 20 subjects. Variables associated with the target-detection task were levels of difficulty and location (central or peripheral) of target. Detection times and detection errors were recorded. The results, which are discussed, indicate that noise-intensity and display-difficulty levels are significantly interrelated with regard to detection speed, but not to detection error. Some noise conditions did enhance performance, but only under the most complex task condition.
Human Factors, Apr. 1972, Vol.14, No.2, p.181-185. Illus. 5 ref.

CIS 72-2635 Cohen A., Anticaglia J.R., Carpenter P.L.
Temporary threshold shift in hearing from exposure to different noise spectra at equal dBA level
The purpose of this study was to determine whether sound-level measurements in dBA could provide a satisfactory indication of hearing-loss risks from exposures to noises differing greatly in spectral shape. The experimental method is described and the results presented and discussed. Somewhat greater hearing losses were found for noises with falling spectra than with rising spectra at comparable dBA levels, but the differences were rather small.
Journal of the Acoustical Society of America, Feb. 1972, Vol.51, No.2 (Part 2), p.503-507. Illus. 14 ref.

CIS 72-2312 Grzebska M., Kuczyński A.
Psychophysiological aspects of noise
Psychofizjologiczne aspekty hałasu [in Polish]
Depending on personal factors, noise may to some degree or other momentarily activate or permanently impair certain psychic phenomena. The physiopathological consequences can always be observed as hearing and other sense-organ lesions (e.g. balance), or nervous or digestive-system lesions. Carbohydrate, lipid and protein metabolism is also affected. The ear is not the only portal of entry for noise; ultrasonic components of intense noise may affect the mucosae of buccal and nasal cavities, the eye and urogenital membranes.
Ochrona pracy, Jan. 1972, Vol. 26, No.1, p.6-7.

CIS 72-2276 Sinsoilliez M.
Road ripper noise
Le bruit provoqué par les marteaux-piqueurs [in French]
Reference to the relevant French legislation, the level of noise produced by various types of compressor taken alone or in combination with the road ripper, and to the source of the noise is followed by a brief review of general noise-control techniques and a description of the relevant techniques at present employed in Germany (air-cooled compressors, insulated by double-walled tents), the USSR (road rippers with telescopic vibration dampers) and in France (diesel-hydraulic compressors in which oil replaces air as the transmission fluid and which produces, together with the road ripper, a total noise level of 83dB).
Prévention et sécurité du travail, 1st quarter 1972, No.91, p.14-20. Illus. 3 ref.

CIS 72-2638 Murry T.
Hyperbaric chamber noise during a dive to 100ft.
Diving in hyperbaric chambers can produce both temporary and permanent threshold shifts. The purpose of the present study was to determine the noise levels in such a chamber during compression to a simulated depth of 30m of sea water. The experimental procedure is described, and the results discussed. Peak noise levels during descent and ascent were in the 2400-4800 Hz octave band (112-108dBA and 120-115dBA, respectively, depending upon the microphone position).
Journal of the Acoustical Society of America, Apr. 1972, Vol.51, No.4 (Part 2), p.1362-1365. Illus. 7 ref.

CIS 72-2101 Industrial noise control directives
Richtlijnen voor de bestrijding van industrieel lawaai [in Dutch]
Noise-control manual for plant and equipment designers, plant managers, industrial medical officers, labour inspectors and machinery buyers. Individual sections are devoted to: noise measurement and analysis; noise control measures; general rules; personal hearing protection equipment. The main body of this booklet is devoted to practical measures for eliminating noise sources or reducing noise propagation, and the diagrammatic illustration of these measures: balancing of rotating parts; resonance suppression; improved lubrication; choice of more suitable materials, impact prevention; aerodynamic measures; silencers and vibration dampers; use of more rigid machine frames; flexible hose couplings; flexible machine mountings.
Commissie voor arbeidsgeneeskundig onderzoek, Gezondheidsorganisatie TNO, Postbus 297, Den Haag, Netherlands, 1972. 52p. Illus. 19 ref.

CIS 72-2531 Warnaka G.E., Miller H.T., Zalas J.M.
Structural damping as a technique for industrial noise control
Damping - which is not to be confused with attenuation - is defined as an energy conversion process in which mechanical energy is transformed into heat energy which is itself dissipated into the environment. It is a useful tool in noise reduction where structural resonance or wave propagation at sonic speeds is responsible for noise radiation. It is also useful in reducing noise originating from mechanical impact and from steady-state excitation. The application and effect of structural damping on noise abatement are illustrated by 5 examples (conveyor exit chute, vibratory feeder, plastic grinder, acoustic enclosure, and vertical turret lathe).
American Industrial Hygiene Association Journal, Jan. 1972, Vol.33, No.1, p.1-11. Illus. 15 ref.

CIS 72-2532 Holmer C.I., Lagace A.
Effect of structural damping on the sound radiated from impacted structures
In the first part of this paper, a mathematical model is developed to permit the estimation of the reduction in impact noise due to the addition of mass, stiffness and damping to an impacted system. The change in peak radiated sound pressure level from an impact is found to be proportional to the change in mass and stiffness of the impacted surface. The second part of the paper presents the results of experiments carried out on a foundry hopper before and after damping; there was substantial agreement between the calculated and measured energy noise reductions.
American Industrial Hygiene Association Journal, Jan. 1972, Vol.33, No.1, p.12-18. Illus. 1 ref.

CIS 72-2084 Dzięgielewski T.
Architectural means of noise reduction
Zwalczanie hałasu metodą rozwiązań budowlanych [in Polish]
The importance of acoustic factors in the design of industrial premises is emphasised and the following aspects are discussed: siting and layout (separation of noisy processes, sound-absorbent walls and corridors); door and window location; ceilings; use of absorbent materials, soundproof cabins, acoustic screens, etc.; practical suppression of impact, motor and machine noise. All noise control measures, from noise reduction at source to use of personal hearing protective equipment, should be integrated.
Ochrona pracy, Jan. 1972, Vol.26, No.1, p.14-16. Illus.

CIS 72-2636 Control of fan and compressor noise
A series of 6 papers presented at a seminar held at Washington, D.C., USA, on 23 April 1971 under the following titles: Sources of noise in axial flow fans; Research on fan noise generation; Theory and measurement of model spectra in hard-walled cylindrical ducts; Analysis, testing and design of lined ducts; Blade interaction noise from lift fans; and In-duct investigation of subsonic fan "rotor alone" noise.
Journal of the Acoustical Society of America, May 1972, Vol.51, No.5 (Part 1), p.1411-1482. Illus. 116 ref.

CIS 72-2301 Lebrun M.
Noise control in a zip-fastener-chain production plant
Lutte contre le bruit dans un atelier de machines à fabriquer la chaîne de fermeture à glissière [in French]
Results of noise control tests in a French zip-fastener plant. Noise level measurements on various machines and in various premises revealed maxima of 103dB. Audiometry of 30 or so workers of both sexes allowed tabulation of threshold shifts in frequency bands between 63 and 8000Hz. Trials with hearing protection equipment (muffs, earplugs, glass fibre wadding) were carried out but it was finally decided to control machine noise at source and trials were made with machine enclosures which produced an average noise-level reduction of 14dB on 12 machines.
Revue de la sécurité, Apr. 1972, Vol.8, No.79, p.7-23. Illus.

CIS 72-2640 Stewart J.S., Hart F.D.
Analysis and control of wood planer noise
Identification of the various sources of noise in single surface planers (the major source was found to be board vibration) and the factors which influence the generation of sound from the board being surfaced. Systematic measurements were carried out to investigate the effect on sound pressure level of board width, board length and cutter-head design. Recommendations are made as regards noise reduction.
Sound and Vibration, Mar. 1972, Vol.6, No.3, p.24-27. Illus.

CIS 72-2085 Miazga J.
Control of automobile noise
Zwalczanie hałasu pojazdów samochodowych [in Polish]
Octave spectra of noise from various automobiles under normal operating conditions are analysed. Noise sources include the engine, fan, transmission, tyres, etc. and, consequently, noise control also depends on the driver and not only on the manufacturer. Standardization of vehicle noise measurement is required, especially in the case of lorries in view of the increase in reaction time caused by prolonged exposure to levels of over 85dBA which, after several hours' driving, may have the same effect as drinking.
Ochrona pracy, Jan. 1972, Vol.26, No.1, p.22-25. Illus.

CIS 72-2396 Noise: General measurement and prevention standards
El ruido - Normas generales para su medición y prevención [in Spanish]
Sections are devoted to: introduction; general information and definitions; noise measurement; noise analysis; permissible levels; noise-level reduction.
Hoja informativa de higiene y seguridad en el trabajo No.10, National Occupational Health and Safety Programme, Provincial Technical Service (Plan national de higiene y seguridad del trabajo, Gabinete técnico provincial), Valencia, Spain, Mar. 1972.6p. Illus. 5 ref.

CIS 72-2705 Moreira N.M., Bryan M.E.
Noise annoyance susceptibility
The variations of annoyance due to tape-recorded noise were studied in 34 normal-hearing subjects. There were significant differences in subjective annoyance rating, and individual annoyance evaluation was stable over a 2-month period. Subjects most sensitive to noise showed greater initial annoyance but their annoyance grew less rapidly with increasing noise level than that of the least sensitive. Noise annoyance susceptibility does not seem dependent on age, sex, education, job responsibility or on Eysenck or Minnesota Multiphasic Personality Inventory scores, but does seem strongly related to Rorschach Projection Test ratings. A tentative personality profile of a noise-sensitive individual is proposed; this profile is supported by field data. Noise annoyance seems dependent not only on noise level but also on the exposed person's personality.
Journal of Sound and Vibration, 22 Apr. 1972, Vol.21, No.4, p.449-462. Illus. 21 ref.

CIS 72-2701 Stephens S.D.G.
Hearing and personality: A review
The personality of individuals interacts with their auditory system in a variety of ways. Subjects with different personalities may differ in their psychological responses to sounds, in their perception of sounds and in the way in which noise influences their performance of various tasks. Severe deafness appears to influence the personality of patients, and fairly characteristic changes are found in specific auditory disorders. The annoyance caused by a variety of noises is influenced by the person's personality and, in the past, a noise annoyance scale hs been used as a measure of neuroticism.
Journal of Sound and Vibration, 8 Feb. 1972, Vol.20, No.3, p.287-298. 92 ref.

CIS 72-2702 Hockey G.R.J.
Effects of noise on human efficiency and some individual differences
A brief review is given of research on the way in which loud noise affects the efficiency of human work, leading to an examination of some differencs between individuals in the extent to which efficiency is affected. Noise is regarded as producing a narrowing of attention towards work components of high priority, an effect which is seen as providing a basis for understanding previous contradictory interpretations in this area. Extroverted people seem more susceptible to this narrowing of attention, while the performance of introverts is more stable. Related research on individual differences in performance, and preference for noisy environments is also discussed.
Journal of Sound and Vibration, 8 Feb. 1972, Vol.20, No.3, p.299-304. Illus. 23 ref.

CIS 72-2704 Stevens. S.S.
Stability of human performance under intense noise
Report of tests to determine the effect of long-term (up to 7h) intense noise exposure (up to 120dB) on various mental, physiological and motor functions. Tests showing detrimental effects of noise were: the temporary hearing-loss test and speech-interference test. Exposure had indeterminate effects on: muscle tension, metabolism, respiration rate, speed of visual accommodation, body sway, reversible visual perspective, dark adaptation and coordinated serial reaction time. Noise had no effect on coordinated serial pursuit, serial disjunctive reaction time, fast-speed pursuit, card sorting, coding performance, judgement of distance, hand steadiness and marksmanship. It is concluded that the efficiency of mental, motor and physiological performance is little affected by noise.
Journal of Sound and Vibration, 8 Mar. 1972, Vol.21, No.1, p.35-56. Illus. 6 ref.

CIS 72-2703 Jackson C.E.P., Grimster W.F.
Human aspects of vibration and noise in helicopters
A survey of the types and sources of helicopter vibration. Methods of vibration testing and monitoring are dealt with and the relative merits of various methods of vibration reduction are reviewed. Acceptable in-service levels of vibration are described in terms of vibration velocity limit and the International Organization for Standardization/British Standards Institution proposals concerning "fatigue-decreased proficiency". Internal and external noise are briefly discussed and some information is given on results of internal cabin-noise reduction.
Journal of Sound and Vibration, 8 Feb. 1972, Vol.20, No.3, p.343-351. Illus. 3 ref.

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