Noise Pollution: Neonatal Aspects

PEDIATRICS ◽  
1974 ◽  
Vol 54 (4) ◽  
pp. 476-479
Author(s):  
Robert W. Miller ◽  
William B. Brendel ◽  
Robert L. Brent ◽  
J. Julian Chisolm ◽  
John L. Doyle ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Rock Music ◽  
Low Frequency ◽  
Noise Pollution ◽  
Sound Level ◽  
Low Frequencies ◽  
Ototoxic Drugs ◽  
Human Ear ◽  
Hospital Noise ◽  
Ototoxic Drug

The deafening effect of high intensity noise is well known—from rock music, aircraft, snowmobiles, motorcycles and the shooting of guns. The effects of hospital noise and its interaction with ototoxic drugs are less well known. The subject is of particular importance to pediatricians, because infants in incubators are exposed to substantial noise from the motor, airflow, respirators, slamming of incubator doors and the baby's own crying. Furthermore, animal experimentation1 shows that the ototoxic drug, kanamycin (often given to the premature infant to combat sepsis), can potentiate the effect of noise on hearing loss as much as 100-fold. Whether or not an interaction between noise and potentially ototoxic drugs occurs in man is as yet unknown. MEASUREMENT Noise has frequency and intensity. Frequency is measured in cycles per second, designated hertz (Hz). The young human ear is sensitive to a frequency range of 20 to 20,000 Hz. White noise, the auditory counterpart of white light, has equal energy in each frequency in the audible range. Intensity is measured in decibels on a scale which is linear with respect to audible frequencies. This measurement is designated dB (linear). Since the human ear is more sensitive to the damaging effects of high frequency sound than to low frequency, a better correlate with noise-induced hearing loss can be obtained when low frequencies are filtered out. Filtered sound level, measured on a so-called A-weighted scale, is designated dB(A). Room conversation produces 60 to 70 dB(A), rock music 100 to 120 dB(A) and snowmobiles 105 to 135 dB(A) for the driver.

Effect of No-load and Load Condition on Transformer Sound

2018 ◽  
pp. 11-15
Author(s):  
Dr. Hitesh Paghadar
Keyword(s):  
Experimental Study ◽  
Power Transformer ◽  
Load Condition ◽  
Noise Pollution ◽  
Sound Level ◽  
Measurement Scale ◽  
Dominant Factor ◽  
Public Attention ◽  
Level Measurement ◽  
Human Ear

Increasing environment noise pollution is a matter of great concern and of late has been attracting public attention. Sound produces the minute oscillatory changes in air pressure and is audible to the human ear when in the frequency range of 20Hz to 20 kHz. The chief sources of audible sound are the magnetic circuit of transformer which produces sound due to magnetostriction phenomenon, vibration of windings, tank and other structural parts, and the noise produced by cooling equipments. This paper presents the validation for sound level measurement scale, why A-weighted scale is accepted for sound level measurement, experimental study carried out on 10MVA Power Transformer. Also presents the outcomes of comparison between No-Load sound & Load sound level measurement, experimental study carried out on different transformer like - 10MVA, 50MVA, 100MVA Power Transformer, to define the dominant factor of transformer sound generation.

The Sound Environment of the Foetal Sheep

Behaviour ◽  
1982 ◽  
Vol 81 (2-4) ◽  
pp. 296-315 ◽  
Author(s):  
B.A. Baldwin ◽  
B.C.J. Moore ◽  
Sally E. Armitage ◽  
J. Toner ◽  
Margaret A. Vince
Keyword(s):  
Sound Pressure ◽  
Body Wall ◽  
Low Frequency ◽  
Sound Level ◽  
The Body ◽  
Human Foetus ◽  
Low Frequencies ◽  
Sound Environment ◽  
High Sound ◽  
Foetal Lamb

AbstractThe sound environment of the foetal lamb was recorded using a hydrophone implanted a few weeks before term in a small number of pregnant ewes. It was implanted inside the amniotic sac and sutured loosely to the foetal neck, to move with the foetus. Results differ from those reported earlier for the human foetus: sounds from the maternal cardiovascular system were picked up only rarely, at very low frequencies and at sound pressures around, or below, the human auditory threshold. Other sounds from within the mother occurred intermittently and rose to a high sound pressure only at frequencies above about 300 Hz. Sounds from outside the mother were picked up by the implanted hydrophone when the external sound level rose above 65-70 dB SPL, and the attenuation in sound pressure was rarely more than 30 dB and, especially at low frequencies, usually much less. However, attenuation due to the transmission of sound through the body wall and other tissues tended to change from time to time. It is concluded that the foetal lamb's sound environment consists of (1) intermittent low frequency sounds associated largely with the ewe's feeding and digestive processes and (2) sounds such as vocalisations from the flock, human voices and other sounds from outside the mother.

Low-Frequency Gain Compensation in Directional Hearing Aids

2002 ◽  
Vol 11 (1) ◽  
pp. 29-41 ◽  
Author(s):  
Todd Ricketts ◽  
Paula Henry
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
Low Frequency ◽  
Sound Quality ◽  
Directional Hearing ◽  
Low Frequencies ◽  
Speech In Noise ◽  
Directional Microphone ◽  
Listening Environments ◽  
Gain Compensation

Hearing aids currently available on the market with both omnidirectional and directional microphone modes often have reduced amplification in the low frequencies when in directional microphone mode due to better phase matching. The effects of this low-frequency gain reduction for individuals with hearing loss in the low frequencies was of primary interest. Changes in sound quality for quiet listening environments following gain compensation in the low frequencies was of secondary interest. Thirty participants were fit with bilateral in-the-ear hearing aids, which were programmed in three ways while in directional microphone mode: no-gain compensation, adaptive-gain compensation, and full-gain compensation. All participants were tested with speech in noise tasks. Participants also made sound quality judgments based on monaural recordings made from the hearing aid. Results support a need for gain compensation for individuals with low-frequency hearing loss of greater than 40 dB HL.

Pendred's Syndrome: A Study of Patients and Relatives

1995 ◽  
Vol 104 (12) ◽  
pp. 957-962 ◽  
Author(s):  
Musa N. Jamal ◽  
Mohammed A. Arnaout ◽  
Ribhi Jarrar
Keyword(s):  
Hearing Loss ◽  
Low Frequency ◽  
Sensorineural Hearing ◽  
The Other ◽  
Test Results ◽  
Profound Hearing Loss ◽  
Low Frequencies ◽  
Pendred’S Syndrome ◽  
Perchlorate Discharge Test ◽  
Discharge Test

Four families, 29 members, with Pendred's syndrome were studied to clarify hearing loss and hormonal status. The ages ranged fro 3 to 50 years. Complete Pendred's syndrome was found in 9 patients. They had bilateral profound hearing loss with residual hearing low frequencies. Goiter was diagnosed at the age of 1 to 14 years with a positive perchlorate discharge test. Twelve of the patient relatives showed partial Pendred's syndrome. Mild sensorineural hearing losses occurred in the low- and medium-range frequencies wi normal perchlorate discharge test results in 6 cases. The other 6 had a slight drop in the perchlorate discharge test results with norm hearing. Five subjects were normal and 3 had normal hormonal and normal perchlorate discharge test results, but were not teste audiologically. This paper shows that patients with Pendred's syndrome may have goiter at birth or develop it between 8 and 14 year that their deafness is bilateral and profound, and that their perchlorate discharge tests are positive. Relatives of Pendred's syndrorr patients showed mild low-frequency sensorineural hearing loss without goiter and normal perchlorate discharge test results in half tl cases, and a slight drop in the perchlorate discharge test results with normal hearing and without goiter in the other half. A correlatic between these findings and genetic studies needs further investigation.

scholarly journals Assessment of the Effects of Superior Canal Dehiscence Location and Size on Intracochlear Sound Pressures

2014 ◽  
Vol 20 (1) ◽  
pp. 62-71 ◽  
Author(s):  
Marlien E.F. Niesten ◽  
Christof Stieger ◽  
Daniel J. Lee ◽  
Julie P. Merchant ◽  
Wilko Grolman ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Temporal Bone ◽  
Semicircular Canal ◽  
Low Frequency ◽  
Low Frequencies ◽  
Superior Canal Dehiscence ◽  
Superior Semicircular Canal ◽  
Wide Range ◽  
Before And After ◽  
Canal Dehiscence

Superior canal dehiscence (SCD) is a defect in the bony covering of the superior semicircular canal. Patients with SCD present with a wide range of symptoms, including hearing loss, yet it is unknown whether hearing is affected by parameters such as the location of the SCD. Our previous human cadaveric temporal bone study, utilizing intracochlear pressure measurements, generally showed that an increase in dehiscence size caused a low-frequency monotonic decrease in the cochlear drive across the partition, consistent with increased hearing loss. This previous study was limited to SCD sizes including and smaller than 2 mm long and 0.7 mm wide. However, the effects of larger SCDs (>2 mm long) were not studied, although larger SCDs are seen in many patients. Therefore, to answer the effect of parameters that have not been studied, this present study assessed the effect of SCD location and the effect of large-sized SCDs (>2 mm long) on intracochlear pressures. We used simultaneous measurements of sound pressures in the scala vestibuli and scala tympani at the base of the cochlea to determine the sound pressure difference across the cochlear partition - a measure of the cochlear drive in a temporal bone preparation - allowing for assessment of hearing loss. We measured the cochlear drive before and after SCDs were made at different locations (e.g. closer to the ampulla of the superior semicircular canal or closer to the common crus) and for different dehiscence sizes (including larger than 2 mm long and 0.7 mm wide). Our measurements suggest the following: (1) different SCD locations result in similar cochlear drive and (2) larger SCDs produce larger decreases in cochlear drive at low frequencies. However, the effect of SCD size seems to saturate as the size increases above 2-3 mm long and 0.7 mm wide. Although the monotonic effect was generally consistent across ears, the quantitative amount of change in cochlear drive due to dehiscence size varied across ears. Additionally, the size of the dehiscence above which the effect on hearing saturated varied across ears. These findings show that the location of the SCD does not generally influence the amount of hearing loss and that SCD size can help explain some of the variability of hearing loss in patients. i 2014 S. Karger AG, Basel

scholarly journals How Can Low-Frequency Noise Exposure Interact with the Well-Being of a Population? Some Results from a Portuguese Municipality

2019 ◽  
Vol 9 (24) ◽  
pp. 5566 ◽  
Author(s):  
Juliana Araújo Alves ◽  
Lígia Torres Silva ◽  
Paula Remoaldo
Keyword(s):  
Urban Areas ◽  
Noise Exposure ◽  
Low Frequency ◽  
Noise Pollution ◽  
Well Being ◽  
Sound Level ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Sound Levels ◽  
Exposed Population

Noise pollution is the second most harmful environmental stressor in Europe. Portugal is the fourth European country most affected by noise pollution, whereby 23.0% of the population is affected. This article aims to analyze the effects of exposure to low frequency noise pollution, emitted by power poles and power lines, on the population’s well-being, based on a study of “exposed” and “unexposed” individuals in two predominantly urban areas in north-western Portugal. To develop the research, we used sound level (n = 62) and sound recording measurements, as well as adapted audiometric test performance (n = 14) and surveys conducted with the resident population (n = 200). The sound levels were measured (frequency range between 10 to 160 Hz) and compared with a criterion curve developed by the Department for Environment, Food and Rural Affairs (DEFRA). The sound recorded was performed 5 m away from the source (400 kV power pole). Surveys were carried out with the “exposed” and “unexposed” populations, and adapted audiometric tests were performed to complement the analysis and to determine the threshold of audibility of “exposed” and “unexposed” volunteers. The “exposed” area has higher sound levels and, consequently, more problems with well-being and health than the “unexposed” population. The audiometric tests also revealed that the “exposed” population appears to be less sensitive to low frequencies than the “unexposed” population.

Preferred Low- and High-Frequency Compression Ratios among Hearing Aid Users with Moderately Severe to Profound Hearing Loss

2007 ◽  
Vol 18 (01) ◽  
pp. 017-033 ◽  
Author(s):  
Gitte Keidser ◽  
Harvey Dillon ◽  
Ole Dyrlund ◽  
Lyndal Carter ◽  
David Hartley
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Fine Tuning ◽  
Adaptive Procedure ◽  
Profound Hearing Loss ◽  
Low Frequencies ◽  
Frequency Compression ◽  
Fast Acting

This study aimed to determine the low- and high-frequency compression ratios of a fast-acting device that were preferred by people with moderately severe to profound hearing loss. Three compression ratios (1:1, 1.8:1, and 3:1) were combined in the low and high frequencies to produce nine schemes that were evaluated pair-wise for three weeks in the field using an adaptive procedure. The evaluation was performed by 21 experienced hearing aid users with a moderately severe to profound hearing loss. Diaries and an exit interview were used to monitor preferences. Generally, the subjects preferred lower compression ratios than are typically prescribed, especially in the low frequencies. Specifically, 11 subjects preferred linear amplification in the low frequencies, and 14 subjects preferred more compression in the high than in the low frequencies. Preferences could not be predicted from audiometric data, onset of loss, or past experience with amplification. The data suggest that clients with moderately severe to profound hearing loss should be fitted with low-frequency compression ratios in the range 1:1 to 2:1 and that fine-tuning is essential. Este estudio trató de determinar las tasas de compresión de alta y baja frecuencia de un dispositivo de acción rápida, que resultara preferido por personas con hipoacusias moderadamente severas a profundas. Se combinaron tres tasas de compresión (1:1, 1.8:1, y 3:1) en las frecuencias graves y agudas para producir nueve esquemas que fueron evaluados en el campo, en pares, durante tres semanas, utilizando un procedimiento de adaptación. La evaluación fue realizada por 21 usuarios experimentados de audífono con hipoacusias moderadamente severas a profundas. Se usaron diarios y un cuestionario final para monitorear las preferencias. Generalmente, los sujetos prefirieron menores tasas de compresión de lo que típicamente se prescribe, especialmente en las bajas frecuencias. Específicamente, 11 sujetos prefirieron la amplificación lineal en las frecuencias graves y 14 sujetos prefirieron más compresión en las frecuencias altas. Las preferencias no podían predecirse a partir de los datos audiométricos, del inicio de la pérdida, o por experiencias anteriores con amplificación. Los datos sugieren que los clientes con hipoacusias moderadamente severas a profundas, deberían adaptarse con tasas de compresión en las frecuencias graves en el rango de 1:1 a 2:1, y que un ajuste fino es esencial.

scholarly journals Control the Frequency Response of a Loudspeaker by Changing Its Enclosure

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Pavlo Olehovych Riabokon
Keyword(s):  
Resonant Frequency ◽  
Resonance Frequency ◽  
Frequency Response ◽  
Rock Music ◽  
Low Frequency ◽  
Total Quality ◽  
Frequency Range ◽  
Low Frequencies ◽  
Frequency Components ◽  
Internal Volume

This article analyzes how to control frequency response of a loudspeaker by changing the volume of its closed-box enclosure. The calculation is performed by the method of  Thiele-Small on the basic of a pre-calculated loudspeaker, the parameters of which are given in third section. This became possible because of the simplification of the circuit on figure 1 to the form of circuit on figure 2. This allowed us to consider it as a second order filter (presence of two reactive elements). Obtained results are compared with corresponding characteristics of open-box enclosure of the same loudspeaker, that was pre-calculated by the author too. Results are presented graphically in figure 3 and 4. As can be seen from them, the resonant frequency of the loudspeaker in the closed-box enclosure is higher than the resonant frequency of the loudspeaker in the open box. The result in the form of a ratio  is listed in table 2. Analyzing the obtained data, it can be noticed that with the change of the internal volume of the closed box (and hence its total quality factor), it is possible to affect both the resonance frequency and the peak amplitude values in these frequencies by changing the FR. The result shown in figure 3 and 4 is achieved by taking into account effect of radiation only on the one side of the driver (in the case of open-box enclosure). Closed box was calculating by taking into account both sides radiation of the driver. Shifting the resonance frequency of the system towards higher frequencies and increasing the sound pressure on the resonance generally worsens the FR of the loudspeaker (reduces the reproduction of low-frequency components of sound and increases the unevenness of the frequency). However, certain variants of this group of frequency characteristics may be useful depending on the reproducible frequency range and need of emphasize the low-frequency components (for example, in rock music). If you need a smoothed low-frequency sound, it is appropriate to use systems with low overall quality and increased internal volume or open-box enclosure. Therefore, the volume of the closed-box enclosure significantly affects the resonant frequency and the shape of the frequency response of the loudspeaker. Reducing the volume of the enclosure of the loudspeaker leads to a decrease in its frequency range due to low frequencies and at the same time increase in the unevenness of the frequency response. The change in the resonant frequency of the system as the volume of the closed-box enclosure decreases, the less the volume of the closed-box.

Noise induced hearing loss in low frequencies in employees in a hospital microbiology department

2021 ◽  
Vol 7 (5) ◽  
pp. 861
Author(s):  
Konstantina Chrysouli ◽  
Dimitrios Kikidis
Keyword(s):  
Hearing Loss ◽  
Low Frequency ◽  
Control Group ◽  
Frequency Noise ◽  
Noise Induced Hearing Loss ◽  
Low Frequency Noise ◽  
Low Frequencies ◽  
History Of ◽  
Laboratory Workers ◽  
The Impact

<p class="abstract">Noise induced hearing loss (NIHL) is regarded as a serious problem and one of the most recorded occupational disorders in Europe and in the rest of the world and amounts to between 7% and 21% of the hearing loss. Aim of this study is to explore the development and the prevalence of low frequency noise-induced hearing loss (NIHL) in a hospital, especially in microbiology laboratory workers. Generally it is known that 4 KHz is the main NIHL frequency. Despite current theories, our study suggests for the first time the impact of low frequency noise in hearing loss among laboratory workers. According to the results, the population examined, namely the employees at the Microbiology Department of the Hospital, showed lower hearing levels compared to the control group, who had no history of occupational exposure to noise. There are many other studies which suggest that prolonged exposures to high noise levels have negative physiological and psychological effects on workers. The finding of the correlation of noise frequency with the frequency of the generated hearing loss is involved in the controversy about the pathophysiology of noise effect.</p>

Assessment of noise from equipment and processes at construction sites

2016 ◽  
Vol 24 (1) ◽  
pp. 21-34 ◽  
Author(s):  
Heow Pueh Lee ◽  
Zhaomeng Wang ◽  
Kian Meng Lim
Keyword(s):  
Rapid Development ◽  
Low Frequency ◽  
Noise Pollution ◽  
Sound Level ◽  
Construction Equipment ◽  
Frequency Noise ◽  
Construction Sites ◽  
Noise Barriers ◽  
Typical Type

Noise pollution from construction sites has become a major problem for major cities with the continued rapid development as well as redevelopment of cities. These construction sites, in particular for new subway systems, are often near to residential and commercial buildings. A better understanding and characterization of noise profiles will be required for project management and planning as well as environmental impact assessment. In this study, instead of using the typical type 1 sound level meters for the measurement of noise profiles emitted from construction equipment and processes commonly done in construction industry, we attempt to characterize the noise profiles of common construction equipment at their respective noise source using an Acoustic Array or Acoustic Camera. The study also highlighted the significant presence of low-frequency noise at construction sites for some construction equipment and processes. This may have some implications for the design of noise barriers at construction sites.

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