Download or read book Use of Animal Test Data in the Development of a Human Auditory Hazard Criterion for Impulse Noise Part 2 written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hearing loss and sensory cell loss data, obtained from 909 chinchillas exposed to one of 137 different impulse noise or blast wave exposure paradigms, were statistically analyzed. The objective was to extract relations between the effects of the exposure on the auditory system (effects metrics) and metrics used to characterize the blast wave exposure. The results of the tests are presented in this second part.
Download or read book Use of Animal Test Data in the Development of a Human Auditory Hazard Criterion for Impulse Noise Part 1 written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hearing loss and sensory cell loss data, obtained from 909 chinchillas exposed to one of 137 different impulse noise or blast wave exposure paradigms, were statistically analyzed. The objective was to extract relations between the effects of the exposure on the auditory system (effects metrics) and metrics used to characterize the blast wave exposure. Specifically the following two questions were asked: (a) What is the best indicator of the amount of hazard associated with an impulse noise exposure? (b) How does the hazard of an impulse noise exposure accumulate with increasing numbers of impulses? Two analytical approaches were used. Both approaches indicated that the P-weighting functions or one of its derivatives (P1-, P2- or R-weighting) best organized the effects metrics. Depending on the analytical approach, either an energy trading rule of 10 log(10) N or 6 log(10) N; where N is the number of impulses, best organized the data for N between 10 and 100. For exposures of between 1 and 10 impulses, a region of the parametric space that is of considerable practical significance, there is insufficient data to form any conclusions. For this region the limited data suggest that an energy trading rule i.e., 10 log N, does not work.
Download or read book A Health Hazard Assessment for Blast Overpressure Exposures Subtitle Use of Animal Test Data in the Development of a Human Auditory Hazard Criterion for Impulse Noise Part 1 written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hearing loss and sensory cell loss data, obtained from 909 chinchillas exposed to one of 137 different impulse noise or blast wave exposure paradigms, were statistically analyzed. The objective was to extract relations between the effects of the exposure on the auditory system (effects metrics) and metrics used to characterize the blast wave exposure. Specifically the following two questions were asked: (a) What is the best indicator of the amount of hazard associated with an impulse noise exposure? (b) How does the hazard of an impulse noise exposure accumulate with increasing numbers of impulses? Two analytical approaches were used. Both approaches indicated that the P-weighting functions or one of its derivatives (P1-, P2- or R-weighting) best organized the effects metrics. Depending on the analytical approach, either an energy trading rule of 10 log10 N or 6 log10 N; where N is the number of impulses, best organized the data for N between 10 and 100. For exposures of between 1 and 10 impulses, a region of the parametric space that is of considerable practical significance, there is insufficient data to form any conclusions. For this region the limited data suggest that an energy trading rule i.e., 10 log N, does not work.
Download or read book A Health Hazard Assessment for Blast Overpressure Exposures Subtitle Use of Animal Test Data in the Development of a Human Auditory Hazard Criterion for Impulse Noise Part 2 written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A health hazard assessment for blast overpressure exposures is presented.
Download or read book The Journal of the Acoustical Society of America written by Acoustical Society of America and published by . This book was released on 2006 with total page 1222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Hazard of Exposure to Impulse Noise as a Function of Frequency written by and published by . This book was released on 1991 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: The energy spectrum of a noise is known to be an important variable in determining the effects of a traumatic exposure. However, existing criteria for exposure to impulse noise do not consider the frequency spectrum of an impulse as a variable in the evaluation of the hazards to the auditory system. This report presents the results of a study that was designed to determine the relative potential that impulsive energy concentrated at different frequencies has in causing auditory system trauma. One hundred and eighteen (118) chinchilla, divided into 20 groups with 5 to 7 animals per group, were used in these experiments. Pre- and post-exposure hearing thresholds were measured at 10 test frequencies between 0.125 and 8 kHz on each animal using avoidance conditioning procedures. Quantitative histology (cochleograms) was used to determine the extent and pattern of the sensory cell damage. The noise exposure stimuli consisted of six different computer-generated narrow band tone bursts having center frequencies located at 0.260, 0.775, 1.350, 2.450, and 3.550 kHz. Each narrow band exposure stimulus was presented at two to four different intensities. An analysis of the audiometric and histological data allowed frequency weighing functions to be derived.
Download or read book A Health Hazard Assessment for Blast Overpressure Exposures Subtitle Evaluation of Impulse Noise Criteria Using Human Volunteer Data written by and published by . This book was released on 1999 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: The evaluation of impulse noise criteria is becoming more critical as many new weapons exceed exposure levels for single hearing protection set forth by the MIL-STD-1474D. Previous man-rating studies have consistently shown that auditory injury does not occur at these levels. Consequently, there is general belief that the current standards under predict the threshold at which injury occurs. Four impulse noise auditory injury criteria adopted by NATO countries, namely, the MIL-STD-1474D (USA), Pfander (Germany), Smoorenburg (Netherlands), and L(Aeq8) (France), are evaluated against human volunteer data. Four data sets from subjects wearing single hearing protection exposed to increasing blast overpressure effects were obtained from tests sponsored by the US Army Medical Research and Materiel Command. Two data sets were obtained from free field and bunker tests using RACAL earmuffs modified to simulate poor fitting. Two other data sets came from the M198 howitzer and Viper man-rating studies using EAR earplugs. Injury threshold was taken as a temporary threshold shift (TTS) >/- 25 ("3 at any frequency. Using logistic regression, the four criteria were each correlated with the test data. The analysis shows that all four criteria are overly conservative by 4-12 ("3. The MIL-STD-1474D for single hearing protection is 9.9 (
Download or read book Investigation and Improvement of Occupational and Military Noise Exposure Guidelines written by Goley George and published by . This book was released on 2010 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noise induced hearing loss is a significant problem in both the occupational and military settings. Current occupational noise guidelines use an energy based noise metric to predict the risk of hearing loss and thus ignore the effect of temporal characteristics of the noise. The practice is widely considered to underestimate the risk of a complex noise environment, where impulsive noises are embedded in a steady-state noise. A basic form for noise metrics is designed by combining the equivalent SPL and a temporal correction term defined as a function of kurtosis of the noise. Several noise metrics are developed by varying this basic form and evaluated utilizing existing chinchilla noise exposure data. It is shown that the kurtosis correction term significantly improves the correlation of the noise metric with the measured hearing losses in chinchillas. One of the investigated metrics, the kurtosis corrected A-weighted SPL, is applied to a human exposure study data as a preview of applying the metrics to human guidelines. A method to remove statistically unlikely outliers from the animal test data is also investigated. In addition to the basic temporal correction term for the characterization of complex noise exposures, a complex noise separation algorithm is explored to further characterize the exposure. In military noise settings, the effects of high intensity, impulsive noise on the auditory system are complex and difficult to quantify in a simple criterion. Several impulse noise criteria (e.g. MIL-STD 1474D, Pfander, Smoorenburg) are studied for their analytic structure to understand underlying basic assumptions. Then, these and other criteria are compared for their performance based on animal blast overpressure data. In occupational and military settings, a frequency-matched, weighted equivalent sound pressure level is investigated. The statistical correlations of this weight are compared with metrics currently in use. The possibility of developing a new noise standards according to the approach adopted in this study as well as remaining challenges are discussed.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book The Role of Peak Pressure in Determining the Auditory Hazard of Impulse Noise written by James H. Patterson (Jr.) and published by . This book was released on 1986 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most current Damage Risk Criteria (DRC) for human exposure to impulse noise are written in terms of peak pressure as the primary index of the traumatic potential or hazard associated with exposure to an impulse noise. Since the peak pressure is only one of many parameters of an impulse, there is a question whether or not a DRC based on peak pressure can reflect accurately the hazard to hearing posed by impulse noise. The experiments described in this report were designed to determine whether peak pressure is an adequate quantifier for an impulse noise DRC. The general approach was to construct two types of impulse noise with the same Fourier pressure spectrum, but with different peak pressures. This makes it possible to compare the hearing loss and injury resulting from impulses which have the same total energy distributed the same way across frequency, but with different peak pressures. The threshold shift measured during the first few hours after exposure showed systematic variation with both peak pressure and energy level. The permanent threshold shift (20 to 30 days postexposure) and the loss of sensory cells showed strong dependence on energy level, with a less pronounced dependence on peak pressure. These results indicate that peak pressure is not a sufficient indicator of auditory hazard; however, energy alone is not a sufficient indicator either. Keywords: Exposure (Physiology), Impulse noise.
Download or read book An Experimental Basis for the Estimation of Auditory System Hazard Following Exposure to Impulse Noise written by and published by . This book was released on 1992 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The energy spectrum of a noise is known to be an important effects of a traumatic exposure. However, existing criteria for exposure to impulse noise do not consider the frequency spectrum of an impulse as a variable in the evaluation of the hazards to the auditory system. This report presents the results of three studies that were designed to determine the relative potential that impulsive energy has in causing auditory system trauma. Four hundred and seventy five (475) chinchilla were used in these experiments. Pre- and post- exposure hearing thresholds were measured on each subject. In the first study, the noise exposure stimuli consisted of six different computer-generated narrow band tone bursts having center frequencies located at 0.260, 0.775, 1.025, 1. 350, 2.450, and 3.550 kHz. Each narrow band exposure stimulus was presented at two to four different intensities. An analysis of the audiometric data allowed a frequency weighting function to be derived. This weighting function de- emphasizes low frequency energy more than the conventional A-weighting function. In the second study, the exposures consisted of two--types of broad band computer synthesized impulses. Subjects were exposed to 100 impulses at a rate of 1-per-3-seconds. Each type of impulse was presented at 3 intensities. The third study used impulses generated by three different diameter shock tubes. Subjects were exposed to 1, 10, or 100 impulses at one of three intensities. The results of the second and third studies were interpreted using the weighting' function derived from the first study. The hearing loss from all three studies is a linear function of the weighted SEL calculated using the weighting function, derived in the first study. Impulse noise, Hearing, Chinchilla, Audiometry and histology.
Download or read book Noise and Military Service written by Institute of Medicine and published by National Academies Press. This book was released on 2006-01-20 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute of Medicine carried out a study mandated by Congress and sponsored by the Department of Veterans Affairs to provide an assessment of several issues related to noise-induced hearing loss and tinnitus associated with service in the Armed Forces since World War II. The resulting book, Noise and Military Service: Implications for Hearing Loss and Tinnitus, presents findings on the presence of hazardous noise in military settings, levels of noise exposure necessary to cause hearing loss or tinnitus, risk factors for noise-induced hearing loss and tinnitus, the timing of the effects of noise exposure on hearing, and the adequacy of military hearing conservation programs and audiometric testing. The book stresses the importance of conducting hearing tests (audiograms) at the beginning and end of military service for all military personnel and recommends several steps aimed at improving the military services' prevention of and surveillance for hearing loss and tinnitus. The book also identifies research needs, emphasizing topics specifically related to military service.
Download or read book Excerpta Medica written by and published by . This book was released on 1991 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Engineering Index Bioengineering Abstracts written by and published by . This book was released on 1987 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cumulated Index Medicus written by and published by . This book was released on 1976 with total page 1584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Anthropogenic Noise on Animals written by Hans Slabbekoorn and published by Springer. This book was released on 2018-08-20 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past several years, many investigators interested in the effects of man-made sounds on animals have come to realize that there is much to gain from studying the broader literature on hearing sound and the effects of sound as well as data from the effects on humans. It has also become clear that knowledge of the effects of sound on one group of animals (e.g., birds or frogs) can guide studies on other groups (e.g., marine mammals or fishes) and that a review of all such studies together would be very useful to get a better understanding of the general principles and underlying cochlear and cognitive mechanisms that explain damage, disturbance, and deterrence across taxa. The purpose of this volume, then, is to provide a comprehensive review of the effects of man-made sounds on animals, with the goal of fulfilling two major needs. First, it was thought to be important to bring together data on sound and bioacoustics that have implications across all taxa (including humans) so that such information is generally available to the community of scholars interested in the effects of sound. This is done in Chaps. 2-5. Second, in Chaps. 6-10, the volume brings together what is known about the effects of sound on diverse vertebrate taxa so that investigators with interests in specific groups can learn from the data and experimental approaches from other species. Put another way, having an overview of the similarities and discrepancies among various animal groups and insight into the “how and why” will benefit the overall conceptual understanding, applications in society, and all future research.
Download or read book Bioengineering Abstracts written by and published by . This book was released on 1987 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt:
