scholarly journals Sound Level Measurements in Berthing Areas of an Aircraft Carrier

2019 ◽  
Vol 63 (8) ◽  
pp. 918-929
Author(s):  
Nicholas Cody Schaal ◽  
Maria Majar ◽  
Andrew Hunter
Keyword(s):  
Sound Level ◽  
Noise Levels ◽  
Aircraft Carrier ◽  
Flight Operations ◽  
Close Proximity ◽  
Hearing Recovery ◽  
Us Navy ◽  
Noise Measurements ◽  
Time Periods ◽  
Hazardous Noise

Abstract Background Personnel assigned to aircraft carriers work and live in environments where hazardous noise areas and hearing recovery spaces such as sleeping areas are in close proximity to one another. Hazardous noise exposure occurring during on-duty time periods and elevated noise levels during off-duty periods in sleeping areas may be prohibiting adequate hearing recovery, thus potentially leading to hearing loss and may lead to adverse effects on sleep, leading to crew-member fatigue. This investigation characterizes Equivalent sound level (Leq) and standardized octave band center frequency noise levels according to berthing (sleeping) area location during flight operation and nonflight operation time periods on a US Navy aircraft carrier. In addition, the investigation compares noise measurements in sleeping areas to noise levels associated with auditory rest and poor sleep quality and quantity. Methods Noise levels were measured in berthing areas aboard a US Navy Nimitz-class aircraft carrier during a routine at-sea period. Sixty noise measurements were taken in eight sleeping locations. Leq in decibels ‘A’ weighted (dBA) and noise levels from 16 to 16 000 Hz in (dB) were measured during flight operations [Leq (flt ops)] and nonflight operations [Leq (nonflt ops)]. Leq was also measured according to sleep area shipboard locations of forward (FWD) Leq (FWD), middle (MID) Leq (MID), and rear (AFT) Leq (AFT). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) for effective quiet areas. In addition, these data were compared to noise levels associated with hearing loss and sleep parameters. Statistical analysis was conducted with R version 3.5.2 using an alpha level of 0.05. Results Leq (flt ops) in sleeping areas was a statistically significant (P < 0.05) 6.4 dBA higher than the Leq (nonflt ops). Leq (FWD) and Leq (MID) in sleeping areas was a statistically significant (P < 0.05) 15.2 and 15.0 dBA higher, respectively, than the Leq (AFT) noise levels. Mean noise levels at standardized center (1/1) octave bands were highest between 500 and 4000 Hz, ranging from 65.2 to 69.8 dB. A total of 72% of all area Leq measurements exceeded the 70 dBA ACGIH TLV classified as effective quiet to allow for temporary threshold shift recovery. All noise measurements exceeded the World Health Organization’s noise threshold where adverse effects on sleep begin. Discussion/Conclusions Results suggest that sleeping area location in close proximity to relatively high noise sources and activities occurring on an aircraft carrier (i.e. flight operations) increase noise levels in sleeping areas. These findings raise serious concerns since high noise exposures both on duty and during off-duty/sleeping periods may inhibit auditory recovery from hazardous noise exposures. In addition, results suggest noise levels in sleeping areas are high enough to evoke negative sleep effects.

scholarly journals Case Study in a Working Environment Highlighting the Divergence between Sound Level and Workers’ Perception towards Noise

2020 ◽  
Vol 17 (17) ◽  
pp. 6122
Author(s):  
Chun-Yip Hon ◽  
Illia Tchernikov ◽  
Craig Fairclough ◽  
Alberto Behar
Keyword(s):  
Noise Exposure ◽  
Health And Safety ◽  
Sound Level ◽  
Working Environment ◽  
Noise Levels ◽  
Hearing Conservation ◽  
Attitudes And Perceptions ◽  
Noise Measurements ◽  
Survey Responses ◽  
Excessive Noise

Excessive noise levels are a prevalent issue in food processing operations and, although there have been numerous studies on occupational noise, no single study has used a concurrent mixed-methods approach. Employing this study design allows for an understanding of the level of convergence (similarity) between measured noise levels and workers’ attitudes and perceptions towards noise. This, in turn, allows for the identification of potential challenges with respect to the implementation of hearing conservation efforts. In this study, spot noise measurements were collected using a sound level meter. One-on-one interviews were conducted with workers to determine attitudes and perceptions towards noise in their workplaces. Subsequently, the results of the noise measurements (quantitative data) were integrated with the survey responses (qualitative data) to identify convergence. The majority of the noise measurements were found to exceed 85 dBA—the criterion mandated by the local occupational health and safety legislation. Although all study participants felt that it was noisy in the workplace, a large proportion of respondents indicated that the noise was not bothersome. With workers’ perception being contradictory to the measured noise levels, it is a challenge to implement hearing conservation measures unless changes are made to raise the awareness of the risks associated with excessive noise exposure.

Effects of Sand Bed Anti-Vibration Mount on Transmitted Noise from Portable On-Site Electricity Generator

2020 ◽  
Vol 15 (2) ◽  
pp. 8-12
Author(s):  
A.S. Aremu ◽  
T.K. Amao ◽  
O.A. Mokuolu
Keyword(s):  
Particle Size ◽  
Noise Reduction ◽  
Fine Sand ◽  
Sound Level ◽  
Sand Particle ◽  
Particle Sizes ◽  
Noise Levels ◽  
Noise Measurements ◽  
Level Meter ◽  
Vibration Noise

This study investigated the effect of different particle sizes of sand bed anti-vibration mount on transmitted noise from a portable on-site electricity generator. Ten sand bed anti-vibration mounts, 650mm x 650mm in cross section and 75mm thickness were prepared with particle sizes ranging from 0.09 to 2.30mm. Noise measurements were taken in the four cardinal directions using Extech HD600 digital sound level meter. The results of the study showed that the ability of the sand particles to dampen vibration noise from the portable electricity generator reduces with increase in particle size. The sand bed anti-vibration mounts reduced noise levels by 0.11 to 2.78 dB(A). However, fine sand bed of particle size 0.09mm and 0.15mm exhibited superiority in noise reduction over all other sand beds. In order to achieve appreciable noise reduction, the use of ISO 14688-1:2002 fine sand category is recommended as anti-vibration mount in combination with other damping methods. Keywords: Electricity generator, noise, sand, particle size and attenuation

Effect of distance from road intersection on developed traffic noise levels

2004 ◽  
Vol 31 (4) ◽  
pp. 533-538 ◽  
Author(s):  
Saad Abo-Qudais ◽  
Arwa Alhiary
Keyword(s):  
Noise Level ◽  
Traffic Noise ◽  
Sound Level ◽  
Signalized Intersections ◽  
Environment Pollution ◽  
Noise Levels ◽  
The Road ◽  
Traffic Intersection ◽  
Noise Measurements ◽  
Level Meter

The main objective of this study was to evaluate the variation in traffic equivalent noise levels as distance from the road intersection increases. To achieve this objective, traffic volume and equivalent noise level were monitored at 40 signalized intersections in Amman, the capital of Jordan. An integrated sound level meter (ISLM) was used to measure 1 min equivalent noise level along all approaches of the evaluated intersections. A total of 3326 noise measurements were performed. The collected data were analyzed to evaluate the variation of noise levels as distance from the intersection increases. The results indicated that equivalent noise levels were significantly affected by distance from the signal stop line. The equivalent noise levels at distances 50 and 100 m from the intersection were found to be 1.5 to 2.0 dB less than those at 0 m. While at 200, 250, and 300 m from the intersection, the monitored equivalent noise levels were found to be 3.8 to 4 dB higher than that at 0 m. At distances farther than 250 m, the measured equivalent noise levels tend to keep constant value of equivalent noise level as distance increased.Key words: noise, traffic, intersection, environment, pollution.

scholarly journals NOISE LEVEL STUDY AND ASSESSMENT IN THE SOUTHERN PART OF PANEVEŽYS

2010 ◽  
Vol 18 (4) ◽  
pp. 271-280 ◽  
Author(s):  
Pranas Baltrėnas ◽  
Egidijus Petraitis ◽  
Tomas Januševičius
Keyword(s):  
Noise Level ◽  
Traffic Flows ◽  
Heavy Vehicles ◽  
Noise Levels ◽  
The World ◽  
Noise Measurements ◽  
Time Periods ◽  
The City ◽  
Level Analysis ◽  
Main Streets

Noise is a relevant problem faced not only by Lithuania but across the world. With motor traffic flow increase, the noise caused by them is also growing and in particular noisy are heavy vehicles and motorcycles. Noise measurements were taken near the main streets in the southern part of Panevežys. Measurements were made during three time periods of the day: in the daytime (from 6 a.m. to 6 p.m.), in the evening (from 6 p.m. to 10 p.m.) and at night (from 10 p.m. to 6 a.m.). In this part of the city noise is mainly generated by cars. The measured noise levels were compared with the noise level limit (NLL) in the measurement places where the NLL is most often exceeded. Noise level analysis and traffic flows are presented in the work. As the performed measurements show, the NLL in the daytime was exceeded by 65%, in the evening by 88%, and at night by 71% of all the total measurements made. The equivalent NLL was exceeded by up to 14 dBA and the maximum NLL – by up to 17 dBA. The highest excess of the NLL was recorded by streets with the heaviest traffic. Santrauka Triukšmas – ne tik Lietuvoje, bet ir visame pasaulyje aktuali problema. Automobiliu srautams vis labiau didejant, dideja ir ju keliamas triukšmas, ypač triukšmingi yra sunkvežimiai ir motociklai. Triukšmo tyrimai atlikti Panevežio pietineje dalyje prie pagrindiniu gatviu. Matavimai vyko skirtingu paros laiku: diena 6–18 val., vakare 18–22 val. ir nakti 22–6 valandomis. Šioje miesto dalyje pagrindine triukšmo priežastis – automobiliai. Triukšmo lygis, išmatuotas vietose, kuriose dažniausiai viršijamas, lyginamas su leidžiamosiomis normomis. Atlikta triukšmo lygiu ir transporto srautu analize. Iš duomenu matyti, kad leidžiamasis triukšmo lygis diena viršytas 65 %, vakare 88 %, o nakti – 71 % atliktu matavimu. Ekvivalentinis triukšmo lygis viršytas iki 14 dBA, o maksimalusis leidžiamasis – iki 17 dB. Labiausiai triukšmo lygis viršijamas prie gatviu, kuriose pravažiuoja daugiausia automobiliu. Резюме Шум является актуальной проблемой не только в Литве, но и во всем мире. С увеличением автомобильных потоков неизбежно увеличивается и вызываемый ими (особенно грузовиками и мотоциклами) шум. Исследования шума проводились в южной части города Паневежиса, вблизи основных улиц в разное время суток: днем с 6 до 18 часов, вечером с 18 до 22 часов и ночью с 22 до 6 часов утра. В этой части города основным источником шума являются автомобили. Измеренные уровни шума были сравнены с допустимыми уровнями для мест, в которых он чаще всего превышен. Произведен анализ уровней шума и транспортных потоков. Из данных измерений видно, что допустимый уровень шума в дневное время был превышен в 65%, вечером – в 88%, а ночью – в 71% проведенных измерений. Эквивалентный уровень шума превышен до 14 дБа, а максимально допустимый – до 17 дБа. Уровни шума особенно увеличены вблизи улиц, по которым проезжает больше всего автомобилей.

Predicting and Controlling Noise Aboard Aircraft Carriers during Flight Operations – Recent Successes

2013 ◽  
Author(s):  
Raymond Fischer ◽  
Kurt Yankaskas ◽  
Jeffrey Komrower ◽  
Leonid Boroditsky
Keyword(s):  
Hearing Loss ◽  
Three Dimensional ◽  
Noise Prediction ◽  
Acoustic Model ◽  
Noise Levels ◽  
Flight Operations ◽  
Damping Material ◽  
The Us ◽  
Us Navy ◽  
Marine Vessels

Shipboard noise prediction software has progressed significantly over the last decade. Studies sponsored by the US Navy have led to the development of software capable of producing a highly accurate, three-dimensional acoustic model of the majority of marine vessels. However, noise on aircraft carriers had not been addressed to date because of the assumption that little could be done to effectively reduce the hazardous noise levels in compartments. A description of recent successful verification of the prediction software and the effective application of a novel sprayon damping material is provided. The goal is to reduce crew hearing loss, annoyance and impact on performance.

An Evaluation of a Shipboard Collision Avoidance Display

2000 ◽  
Vol 44 (21) ◽  
pp. 3-431-3-434 ◽  
Author(s):  
WK Krebs ◽  
TV Evanoff ◽  
MJ Sinai
Keyword(s):  
Situational Awareness ◽  
Group Formation ◽  
Visual Navigation ◽  
Display Condition ◽  
Immediate Feedback ◽  
Aircraft Carrier ◽  
Conducting Plane ◽  
Flight Operations ◽  
Close Proximity ◽  
Potential Applications

Background: Navigating a ship at night in close proximity to another vessel is a dangerous task. To increase the conning officer's situational awareness, we propose a visual navigation display mounted on the stern of the aircraft carrier that will assist shipboard conning officers when maneuvering in a battle group formation. Methods: To test the effectiveness of the visual navigation display, the aircraft carrier and plane guard vessel were modeled in a virtual environment. Results: The navigation display condition had significantly fewer range and bearing errors than to the non-navigation display condition. The navigation display provided immediate feedback as to whether the aircraft carrier had changed bearing or speed, thus enabling the operator to initiate the appropriate input to maintain station astern of the carrier. Conclusions: Actual or potential applications of this research include combatants conducting plane guard duties astern of an aircraft carrier during flight operations and ships in underway replenishment waiting station.

Determination of the Probability Distribution of the Mean Sound Level

2010 ◽  
Vol 35 (4) ◽  
pp. 543-550 ◽  
Author(s):  
Wojciech Batko ◽  
Bartosz Przysucha
Keyword(s):  
Probability Distribution ◽  
Probability Distribution Function ◽  
Mean Value ◽  
Sound Level ◽  
Function Form ◽  
Noise Levels ◽  
Logarithmic Mean ◽  
The Mean ◽  
Estimation Of Uncertainty

AbstractAssessment of several noise indicators are determined by the logarithmic mean <img src="/fulltext-image.asp?format=htmlnonpaginated&src=P42524002G141TV8_html\05_paper.gif" alt=""/>, from the sum of independent random resultsL1;L2; : : : ;Lnof the sound level, being under testing. The estimation of uncertainty of such averaging requires knowledge of probability distribution of the function form of their calculations. The developed solution, leading to the recurrent determination of the probability distribution function for the estimation of the mean value of noise levels and its variance, is shown in this paper.

Incubator Noise

PEDIATRICS ◽  
1975 ◽  
Vol 56 (4) ◽  
pp. 617-617
Author(s):  
Gōsta Blennow ◽  
Nils W. Svenningsen ◽  
Bengt Almquist
Keyword(s):  
Low Frequency ◽  
Sound Level ◽  
Noise Levels ◽  
Frequency Sound ◽  
Mechanical Noise ◽  
Sound Levels ◽  
Infant Incubator ◽  
Improved Model ◽  
Model C

Recently we reported results from studies of incubator noise levels.1 It was found that in certain types of incubators the noise was considerable, and attention was called to the sound level in the construction of new incubators. Recently we had the opportunity to study an improved model of Isolette Infant Incubator Model C-86 where the mechanical noise from the electrically powered motor has been partially eliminated. With this modification it has been possible to lower the low-frequency sound levels to a certain degree in comparison to the levels registered in our study.

scholarly journals Background noise analysis in urban airport surroundings of Brazilian cities, Congonhas Airport, São Paulo

2016 ◽  
Vol 50 (0) ◽  
Author(s):  
Fabio Scatolini ◽  
Cláudio Jorge Pinto Alves
Keyword(s):  
Traffic Control ◽  
Background Noise ◽  
Noise Analysis ◽  
Exposure Level ◽  
Noise Levels ◽  
Sound Exposure ◽  
Operational Characteristics ◽  
Data Compilation ◽  
Noise Measurements ◽  
Noise Data

ABSTRACT OBJECTIVE To perform a quantitative analysis of the background noise at Congonhas Airport surroundings based on large sampling and measurements with no interruption. METHODS Measuring sites were chosen from 62 and 72 DNL (day-night-level) noise contours, in urban sites compatible with residential use. Fifteen sites were monitored for at least 168 hours without interruption or seven consecutive days. Data compilation was based on cross-reference between noise measurements and air traffic control records, and results were validated by airport meteorological reports. Preliminary diagnoses were established using the standard NBR-13368. Background noise values were calculated based on the Sound Exposure Level (SEL). Statistic parameters were calculated in one-hour intervals. RESULTS Only four of the fifteen sites assessed presented aircraft operations as a clear cause for the noise annoyance. Even so, it is possible to detect background noise levels above regulation limits during periods of low airport activity or when it closes at night. CONCLUSIONS All the sites monitored showed background noise levels above regulation limits between 7:00 and 21:00. In the intervals between 6:00-6:59 and 21:00-22:59 the noise data, when analyzed with the current airport operational characteristics, still allow the development of additional mitigating measures.

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