TECHNICAL NOTES AND RESEARCH BRIEFS

16.3; 5.5; 13.11n, 13.11

AWARD v•rINNING ACOUSTIC DEVICES

EACH YEAR, INDUSTRIAL I•gSEARCH INC. examines the year's technical products and selects the 100considered "most significant" for the year. The list for 1968, which was announced at an award-presentation ban- quet on 4 October and reported in In- dustrial Research for December 1968, in- cludes five examples of applied acoustics.

In one, the "MS-110 Ultrasonic Rapid Sector Imaging System, high-speed ultra- sonic sector scanning is combined with fluoroscopy in a unique system that permits visualization of internal motion and third-

dimension view of heart walls, heart valves, and other internal structures.

"Pericardial effusion can be diagnosed by the system because it projects cross-section images through the same plane in rapid succession. The cross-section image shows the separation between pericardium and heart muscle, thus displaying the presence of fluid in the space.

"The scanning instrument's oscillating contact-type transducer is mounted on the tracks on which the compression cone diaphragm of the fluoroscope usually travels, and is positioned in the center of the view field of the fluoroscopic system. The fluoroscopic image pinpoints the region of the body the ultrasonic device is scan- ning. Simultaneous observation is provided by sector-scan display on a cathode ray tube arranged side by side with the fluoro- scopic display screen.

"Three-dimensional interpretation is pro- vided by the MS-110 because the sector scan presents a cross-section and the fluoroscope shows what is essentially a plan view. The system was developed in a two- year joint research project by the Depart- ment of Radiology, Presbyterian-St. Luke's Hospital, and the Medical Div., Magnaflux Corp., both in Chicago. Developers were John J. Flaherty and Peter J. Rosauer,

engineers, Magnaflux Corp.; and Dr. John W. Clark, radiologist, Presbyterian-St. Luke's Hospital."

A second acoustic prize winner was an evoked response audiometer that "deter- mines auditory thresholds in acoustically handicapped children and uncooperative subjects." "The Model 140 'Evoked Re- sponse Audiometer,' developed at Princeton Applied Research Corp., Princeton, N.J., is the first practical, economical system developed for objectively evaluating audi- tory acuity in babies, small children, and uncooperative adults. It is useful in both research and clinical applications, and also can serve as a general-purpose evoked response system with other types of input stimuli such as photic and tactile.

"An efficient analog-type signal averag- ing computer, a newly developed audio- meter, and solid-state EEG amplifier operate to average electro-encephalographic responses to a series of auditory stimuli. The system provides a wide range of critical parameters: tone frequency, intensity level, pulse duration, pulse repetition rate, rise and fall times, total number of pulses, integrating time constant, sweep duration, recorder chart speed, EEG amplifier gain, and high and low EEG frequency roll-offs. Developers were Dr. Drance de Arnorim, director, medical instrumentation; and Daniel McCabe, development engineer."

The third device honored with an award

was a pulse Doppler sonar navigator, which "gives true vector ground speed as meas- ured in terms of the Doppler shift on the echo, thus providing an accurate source of data for automatic dead reckoning. "The navigation and positioning system features a pulsed sonar that radiates four beams of 400 kHz sonic energy towards the ocean bottom. Echo received over each beam

provides a measure of the Doppler shift. True speed and track of the vessel are provided by processing these returns. By combining these inputs with compass data, the computer provides accurate, completely

automatic dead reckoning navigation. L. O. Vladimir, principal engineer, J. R. Coulter, engineer, and G. Stavis, depart- ment manager, developed the system, which is produced by Singer-General Precision Inc., GPL Div., Kearfott Group, Pleasant- ville, N.Y."

The fourth and fifth acoustic products included in the list of 100 were two of three

Honeywell Inc. electronic systems, which won a combined award. The "Acoustic

Position Reference System (APRS)," developed by the company's Marine Systems Center, Seattle, is a sonar system for precise determination of vessel position relative to an underwater reference point. Accuracy to within 8% of water depth is obtained by the system, which employs a single underwater beacon at the reference point, a shipboard array of hydrophones for receiving the signal from the beacon, and a shipboard signal-processing and display console, which computes the ship position and indicates it on a geographical X-Y display. Position is determined by measur- ing the differences in time of arrival of the beacon signal at the hydrophones. De- velopers were I. Gil Raudsep, marine products planning manager, and Don D. Uhrich, senior development engineer."

The "Acoustic Control and Telemetry System" (ACTS), also from the Seattle Marine Systems Center, provides remote control and monitoring of underwater equipment without intervening physical connections. It comprises a battery- powered underwater unit that interfaces with equipment to be controlled, and a shipboard system with a control panel for transmitting commands to the underwater unit and displaying the received data. The system provides both discrete and con- tinuous control and data telemetry. Security coding of all signals assures error- free operation. Principal ACTS developers were James A. Lagoe, project supervisor, and Dan H. Kusaka, principal development engineer."•

9.8

IT HAD TO HAPPEN...

SOONER OR LATER, THAT IS. it seems that after centuries of unassisted do-it-yourself varieties of oratorical boo-boos (the symp- toms of foot-in-mouth disease), man can

now talk through his hat with electronic assistance for louder errors and assurance

of greater coverage. We call to your atten- tion Patent 3,442,224 which describes a hat shaped like a fireman's helmet, which con- tains a microphone, amplifiers, and loud-

speaker (and note without comment that it was issued to an advertising agency). So, if you should find people saying to you "Will you please turn down your hat!," think about it--they may be trying to tell you something.•

3.1

NEW TECHNICAL REPORTS

Characteristics of Sea Reverberation-- V. V. Ol'shevskii, Consultants Bureau/ Plenum Press, New York, 1967, 159 pp., $19.50. An analysis of the statistical char- acteristics of sea reverberation on the basis

of a discrete model of sound scattering by inhomogeneities in the ocean medium and

irregularities at it• boundaries. Also con- sidered in this translation from the Russian

are specific problems related to the nature of the transmitted signal, the bandpass characteristics of the receiver and motions of the acoustic source.

Acoustic Provinces of the North Pacific Based on Deep-Sea Cores (A Prelimi- nary Survey)--D. R. Horn et al., Lamont

Geological Observatory of Columbia Uni- versity, Palisades, New York, for the Navy, Dec. 1967, 67 pp., AD-671864.

Hearing Loss, Hearing Aids, and the Elderly,--1968, 390 pp. il. Y4. Ag 4:H 35, presents hearings, held before the Sub- committee on Consumer Interests of the

Elderly of the Senate Special Committee on Aging, 90th Congr., 2nd session, 18 and 19

The Journal of the Acoustical Society of America 1061

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TECHNICAL NOTES AND RESEARCH BRIEFS

July 1968, concerning the consumer interest and public health aspects of hearing loss, hearing aids, and the elderly. This report is available from Supt. of Documents, Gov't. Printing Office, Washington, D.C. 20402, for $1.50. N

Hearing Status and Ear Examination Findings Among Adults: United States, 1960-1962-- PHS Publication No.1000, Series 11, No. 32, National Center for Health Statistics, U.S. Department of Health, Education, and Welfare, Washing- ton, D.C., 1968, 28 pp. The National Center for Health Statistics has released a

report that compares the four methods used in the Health Examination Survey in 1960-1962 for determining hearing status among adults and assessing their relation- ship to ear examination findings and certain medical history items.

Hearing status was determined by pure- tone, air-conduction audiometric tests; by self-evaluation of hearing (good, fair, or poor); by self-evaluation of hearing trouble (trouble or none); and by household inter- view of the examinee or a knowledgeable adult in his family regarding his hearing impairment (deafness or serious trouble hearing).

In general, findings in 1960-1962 on hearing among a probability sample of adults aged 18-79 years in the civilian, noninstitutional population of the United States indicate that on the basis of audio- metric tests, 47% of the adults in the United States had "better than normal" hearing; 46% had "normal" hearing; and 7% had some hearing impairment. Through the self-administered medical history used in the survey, an estimated 3% of the adult population considered their hearing to be poor, 25% reported it to be fair, and 72% indicated that it was good. Hearing trouble was reported among an estimated 15% of the adults, while the remaining 85% indi- cated no trouble. According to the house- hold interview, less than 6% of the adults in this country have some degree of serious hearing impairment.

The ear examination by the staff physi- cian included an inspection of the external ear for malformations and a limited examin- ation with an otoscope of the auditory canal for exudate and of the drum for perforation or scarring.

Medical history questions about condi- tions that may affect hearing--such as tinnitus or dizziness or a history of stroke,

scarlet fever, or diphtheria--are also considered.

Prevalence estimates for these various

conditions among the civilian, noninstitu- tional population of the United States, 18-79 years of age, based on the survey findings are shown, as well as the extent of agreement among the general, but par- ticularly with reference to audiometric test data.

Copies of this report may be purchased for $0.35 from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. N

Proceedings of the Conference on Noise as a Public Health Hazard.rain early summer of 1968, national attention was focused on the effect of noise on man and

his environment--from the problem of sonic boom to the incessant chatter of a road

worker's jackhammer. Sponsored jointly by the American

Speech and Hearing Association and the Public Health Service, the two-day Wash- ington Conference on Noise as a Public Health Hazard brought together experts from all walks of life:scientists, researchers, lawyers, businessmen, public officials, and concerned laymen. The' papers presented include reports of noise studies; psycho- logical, medical, and materials tests; and examinations of the sociological implica- tions and long-range health effects of noise- polluted environments.

Numerous points are in dispute, yet one fact is clear: noise is a problem and deserves immediate attention.

The full proceedings of this confer- ence, almost 500 pages with 122 figures and 32 tables, will be published in early 1969.

Only a limited number of copies of Noise as a Public Health Hazard will be available, at $5.00 per copy. Order from Noise Con- ference Proceedings, American Speech and Hearing Association, 9030 Old Georgetown Road, Washington, D.C. 20014.•

Criteria for Assessing Hearing Damage Risk from Impulse-Noise Exposure-- R. Ross, A. CoNes, Christopher G. Rice, Georges R. Garinther, and David C. Hodge, U.S. Army Human Engineering Labora- tories, Aberdeen Proving Ground, Mary- land 21005, August 1967, 58 pp., Clearing- house No. AD 666206.--This paper presents criteria for assessing damage risk from impulse-noise exposure. The criteria

are based on conclusions of independent British and American studies and on the work of other research workers in this field. Most of the studies that led to these criteria

were performed with noise from small arms, but the criteria are general enough to permit assessment of most other types of impulse noise. The variables that must be considered in determining the potential hearing hazard and in making practical application of the criteria are presented, and the parameters that must be measured are defined. The measurement technique and type of transducers to be used are discussed.•

The Effects of Background Noise Upon Perceived Noisiness--David C. Nagel, John E. Parnell, and Hugh J. Parry. Prepared for The Department of Trans- portation Federal Aviation Administration under Contract No. FA65WA-1180 by Bolt Beranek and Newman Inc., 15808 Wyan- dotte Street, Van Nuys, California 91406.-- Cross-modality tests, in which subjects matched the apparent intensity of a 100-Hz vibration applied to the fingertip to the noisiness of «-oct bands of noise with center frequencies of 125, 1000, and 4000 Hz, have been conducted to measure the effects of

background noise upon the judged noisiness of the bands of noise. The tests have

indicated that the growth function for noisiness behaves somewhat like a modified

function of the form f=k(I'•-Io'•), where • is noisiness, I is the intensity of the stimulus, I0 is the threshold intensity for the stimulus in a given background noise and k and n are constants that depend upon the frequency of the stimulus noise band. On the basis of the results of the cross-modality tests, a calculation scheme has been devel- oped to account for the effects of back- ground noise in the perceived noise-level calculation. The calculation procedure reduces, differentially, the sound pressure level of each «-oct band of the judged noise by an amount dependent upon the signal-noise-to-background-noise ratio in that frequency band. For signal-noise-to- background-noise ratios of greater than 65 dB, the band correction is equal to zero. However, preliminary calculations have shown that for realistic background spectra and signal-noise-to-background-noise ratios of 40 dB, the effect upon the perceived noise level of a judged noise, as predicted by the calculation scheme, is approximately 3 PNdB.•-•

1062 Volume 45 Number 4 1969

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