scholarly journals Acoustic Predictions in Industrial Spaces Using a Diffusion Model

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Alexis Billon ◽  
Judicaël Picaut ◽  
Vincent Valeau ◽  
Anas Sakout
Keyword(s):  
Diffusion Equation ◽  
Noise Exposure ◽  
Low Noise ◽  
Working Environment ◽  
Noise Levels ◽  
Sound Sources ◽  
Flexible Tool ◽  
Virtual Factory ◽  
Prediction Tools ◽  
Computation Load

Industrial spaces are known to be very noisy working environment. This noise exposure can be uncomfortable, tiring, or even harmful, at worst. Industrial spaces have several characteristics: they are often huge flat volumes fitted with many obstacles and sound sources. Moreover, they are usually surrounded by rooms where low noise levels are required. The existing prediction tools can seldom model all these phenomena accurately. In this paper, a prediction model based on a diffusion equation is presented. The successive developments carried out to deal with the various propagating phenomena met in industrial spaces are shown. For each phenomenon, numerical or experimental examples are given to highlight the validity of this model. It is also shown that its computation load is very little in comparison to ray-tracing-based methods. In addition, this model can be used as a reliable and flexible tool to study the physics of the coupling between rooms. Finally, an application to a virtual factory is presented.

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.

Blow-Down Valve Noise and Interactions With Downstream Orifice Plates

2003 ◽  
Author(s):  
Denis G. Karczub ◽  
Fred W. Catron ◽  
Allen C. Fagerlund
Keyword(s):  
Noise Exposure ◽  
Control Valve ◽  
Low Noise ◽  
Noise Levels ◽  
Exposure Limits ◽  
Blow Down ◽  
Gas Processing ◽  
The Impact ◽  
Acoustic Fatigue ◽  
Infrequent Event

In a blow-down situation as might occur at a natural gas processing facility, noise levels are very high and significantly exceed the noise levels one would normally associate with a control valve. As the blow-down operation is an infrequent event, this may be permissible but requires consideration of the duration of these high noise levels to ensure that occupational noise exposure limits and acoustic fatigue limits are not exceeded. Tests of noise levels due to an 8-inch control valve in a 12-inch pipeline under blow-down conditions are compared here with noise level predictions based on the IEC standard. Consideration is also given to the impact of placing an orifice plate downstream of the control valve as is often done to reduce pressure drop across the valve in the expectation that control valve noise levels will be reduced. Simple orifice plates often installed by plant operators to achieve this goal are shown to have an adverse impact, and it is shown that a multi-hole diffuser or low-noise control valve should instead be used.

scholarly journals The Impact of Thin Asphalt Layers as a Road Traffic Noise Intervention in an Urban Environment

2021 ◽  
Vol 13 (22) ◽  
pp. 12561
Author(s):  
Ablenya Grangeiro de Barros ◽  
Jarl K. Kampen ◽  
Cedric Vuye
Keyword(s):  
Noise Exposure ◽  
Road Traffic ◽  
Traffic Noise ◽  
Low Noise ◽  
Urban Environments ◽  
Comfort Level ◽  
Road Traffic Noise ◽  
Acoustic Measurements ◽  
Noise Levels ◽  
The Impact

Low-noise thin asphalt layers (TALs) are a feasible solution to mitigate road traffic noise in urban environments. Nevertheless, the impacts of this type of noise intervention are reported mostly regarding noise levels, while non-acoustic aspects influencing the population perception are still little-known. This study investigates the implementation of TALs in two streets of Antwerp, Belgium. The effectiveness of the intervention was measured via noise modelling and acoustic measurements of road traffic noise. A reduction of 2.8 dB in noise exposure was observed in Lden and Lnight, while SPB measurements showed decreases up to 5.2 dB on the roadside. The subjective impacts of the TALs were evaluated via self-administered surveys and compared to results from control streets. The annoyance indicators were positively impacted by the TALs implementation, resulting in annoyance levels similar or lower than in the control streets. The TALs did not impact the reported physical complaints, sleep quality, and comfort level to perform activities.

scholarly journals Noise perception and hearing protector use in metallurgical industries

2018 ◽  
Vol 2 (1) ◽  
pp. 18-28
Author(s):  
I. C. Wictor ◽  
A. A. de P. Xavier
Keyword(s):  
Noise Exposure ◽  
Working Environment ◽  
Noise Levels ◽  
The Social ◽  
Hearing Protectors ◽  
Temporary Solution ◽  
Increasing Risk ◽  
Hearing Protector ◽  
Effective Use ◽  
Safety Procedures

Although hearing protectors are defined as a temporary solution, they are often widely employed as the only measure against noise exposure. However, it is also known that unless workers wear the hearing protector continuously, their effectiveness will be very low. In this regard, there are some surveys that show that workers do not always wear their protectors properly and consistently while exposed to noise. The purpose of this article is to present the results of an investigation about noise perception, relating with noise exposure in working environment and the hearing protectors’ use. Was consider that noise perceptions effects can support minimizing risk and improve industries safety polities. The study sample was carry out in 5 metallurgical industries and 243 workers from Parana – Brazil. The survey data was collected and analyzed by Statistical Package for the Social Sciences (SPSS). The questionnaire results showed that workers are exposed at high noise levels, in increasing risk of developing noise-induced hearing loss (NIHL). About the hearing protection use, it can be evaluated that the use is more effective in companies with a higher level of noise exposure. The perception of risk plays a fundamental role, which predicts the use of hearing protectors; therefore, the perception of the work environment, regarding the lower or higher risk, can be directly linked to the use of hearing protectors. The companies with more rigorous safety procedures also indicate a greater report of effective use of hearing protectors.

scholarly journals A Quantitative General Population Job Exposure Matrix for Occupational Noise Exposure

2020 ◽  
Vol 64 (6) ◽  
pp. 604-613 ◽  
Author(s):  
Zara Ann Stokholm ◽  
Mogens Erlandsen ◽  
Vivi Schlünssen ◽  
Ioannis Basinas ◽  
Jens Peter Bonde ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Fixed Effects ◽  
Large Scale ◽  
Noise Exposure ◽  
Working Environment ◽  
Occupational Noise ◽  
Noise Levels ◽  
Job Exposure Matrix ◽  
Occupational Noise Exposure ◽  
Exposure Levels

Abstract Occupational noise exposure is a known risk factor for hearing loss and also adverse cardiovascular effects have been suggested. A job exposure matrix (JEM) would enable studies of noise and health on a large scale. The objective of this study was to create a quantitative JEM for occupational noise exposure assessment of the general working population. Between 2001–2003 and 2009–2010, we recruited workers from companies within the 10 industries with the highest reporting of noise-induced hearing loss according to the Danish Working Environment Authority and in addition workers of financial services and children day care to optimize the range in exposure levels. We obtained 1343 personal occupational noise dosimeter measurements among 1140 workers representing 100 different jobs according to the Danish version of the International Standard Classification of Occupations 1988 (DISCO 88). Four experts used 35 of these jobs as benchmarks and rated noise levels for the remaining 337 jobs within DISCO 88. To estimate noise levels for all 372 jobs, we included expert ratings together with sex, age, occupational class, and calendar year as fixed effects, while job and worker were included as random effects in a linear mixed regression model. The fixed effects explained 40% of the total variance: 72% of the between-jobs variance, −6% of the between-workers variance and 4% of the within-worker variance. Modelled noise levels showed a monotonic increase with increasing expert score and a 20 dB difference between the highest and lowest exposed jobs. Based on the JEM estimates, metal wheel-grinders were among the highest and finance and sales professionals among the lowest exposed. This JEM of occupational noise exposure can be used to prioritize preventive efforts of occupational noise exposure and to provide quantitative estimates of contemporary exposure levels in epidemiological studies of health effects potentially associated with noise exposure.

Damage Risk: An Evaluation of the Effects of Exposure to 85 versus 90 dBA of Noise

1976 ◽  
Vol 19 (2) ◽  
pp. 216-224 ◽  
Author(s):  
James T. Yates ◽  
Jerry D. Ramsey ◽  
Jay W. Holland
Keyword(s):  
White Noise ◽  
Statistical Difference ◽  
Noise Exposure ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Noise Levels ◽  
Potential Damage ◽  
Full Day ◽  
Damage Risk

The purpose of this study was to compare the damage risk of 85 and 90 dBA of white noise for equivalent full-day exposures. The damage risk of the two noise levels was determined by comparing the temporary threshold shift (TTS) of 12 subjects exposed to either 85 or 90 dBA of white noise for equivalent half- and full-day exposures. TTS was determined by comparing the pre- and postexposure binaural audiograms of each subject at 1, 2, 3, 4, 6, and 8 kHz. It was concluded that the potential damage risk, that is, hazardous effect, of 90 dBA is greater than 85 dBA of noise for equivalent full-day exposures. The statistical difference between the overall effects of equivalent exposures to 85 dBA as compared to 90 dBA of noise could not be traced to any one frequency. The damage risk of a full-day exposure to 85 dBA is equivalent to that of a half-day exposure to 90 dBA of noise. Within the limits of this study, TTS t was as effective as TTS 2 for estimating the damage risk of noise exposure.

Aircraft Noise Levels, Annoyance and General Health of Residents of Communities contiguous to a Major Airport in Lagos State

2020 ◽  
Vol 8 (4) ◽  
pp. 47-59
Author(s):  
Iheanyichukwu M. Elechi
Keyword(s):  
Health Status ◽  
General Health ◽  
Noise Exposure ◽  
Aircraft Noise ◽  
Poor Health ◽  
Noise Levels ◽  
General Health Status ◽  
Lagos State ◽  
Distant Location ◽  
Self Reported Health Status

The purpose of this study was to investigate the relationship between the aircraft noise exposure, annoyance reactions and health status of the residents living within the vicinity of the Murtala Muhammed International Airport (MMA) in Lagos state, Nigeria. Aircraft noise monitoring was conducted in five locations within the vicinity (0-5Km) of MMA, and a sixth distant location (14km away). Levels of aircraft noise for all five locations within the vicinity of the airport exceeded the EPA Victoria threshold of 75 dB LAmax for the residential area (outdoor). A survey on annoyance induced by aircraft noise exposure and general health status was conducted on 450 local residents in the study locations using the International Commission on Biological Effect of Noise question and a single question that has been applied in Dutch national health care surveys since 1983 on self-reported general health status respectively. Percentage of residents within the vicinity of MMA that were highly annoyed (%HA) exceeded 15% guideline limit stipulated by Federal Interagency Committee on Urban Noise while 14.5% reported poor health status. There was a significant association between the annoyance reactions and aircraft noise levels in the study locations while the association between self-reported health status and aircraft noise levels was not significant. Taken together, the residents within the vicinity of the airport are exposed to aircraft noise levels above permissible limit which may be associated with high annoyance reaction but may not be associated with poor health rating. Evidence-based aircraft noise related policies by government are advocated.

Choice and Exchange of Lubricating Oil for Injection Molding Machine

2019 ◽  
Vol 12 (4) ◽  
pp. 378-382
Author(s):  
Shan Syedhidayat ◽  
Quan Wang ◽  
Al-Hadad M.A.A. Mohsen ◽  
Jinrong Wang
Keyword(s):  
Injection Molding ◽  
Dimensional Accuracy ◽  
Low Noise ◽  
Working Environment ◽  
Lubricating Oil ◽  
Lubrication System ◽  
Molding Machine ◽  
Oil And Grease ◽  
Injection Molding Machine ◽  
The Stability

Background: One of the most common manufacturing equipment for polymer product is injection molding machine. In order to ensure the precise, stable and continuous operation of the injection molding machine, the maintenance of the lubrication system must be done well. The stability, reliability, rationality and low noise performance of the lubrication system of injection molding machine directly affect the quality of injection products, dimensional accuracy, molding cycle, working environment and maintenance. Objective: The purpose of this study is to introduce the methods of choice, maintenance of lubricating oil for injection molding machine from many literatures and patents in the recent years, such as lubricating oil device, lubricating composite and structure. Methods: An example of the 260M5 automatic injection molding machine is introduced for the inspection and maintenance of the lubrication system including lubricating oil and lubricating grease. Results: To ensure the lubrication of the injection molding machine, it needs to strictly observe the lubrication time and modulus of the injection molding machine. It needs to strictly control the temperature rise of the lubricating oil and select the correct lubricating oil and grease to ensure the lubrication quality. Conclusion: In the operation of the injection molding machine, it is necessary to check that the lubricating oil is sufficient and the lubricating points are working properly. It ensures sufficient lubrication of the injection molding machine and strictly observes the lubrication time and modulus of the injection molding machine. The stored lubricating oil should be sealed well to prevent air pollution.

scholarly journals 303 What goes bump in the night? A literature review and noise exposure experiment in a UK paediatric emergency department

2020 ◽  
Vol 37 (12) ◽  
pp. 841.1-841
Author(s):  
Lucy Hall ◽  
Sophie Dando ◽  
Anthony Hanks
Keyword(s):  
Emergency Department ◽  
Literature Review ◽  
Literature Search ◽  
Noise Exposure ◽  
Cochrane Library ◽  
Noise Levels ◽  
Paediatric Emergency Department ◽  
Paediatric Emergency ◽  
Sound Levels ◽  
Exposure Experiment

Aims/Objectives/BackgroundIn the Emergency department (ED), noise is a frequent and often unavoidable consequence of work undertaken and levels can often be raised during the day and night. Raised ambient noise levels have potential implications for the workforce, patients and relatives.Investigation into the problem of noise levels in the ED follows feedback from a young patient who couldn’t sleep during a prolonged stay. His complaint focused on loud, irregular banging noises such as those from closing bins that kept him awake.The team felt work should be done to see if it was a wider spread problem or just isolated to his case. A simple sound recording experiment and literature search was conducted.Methods/DesignThe literature search was conducted using electronic/online databases (Medline; Cochrane library) with a fixed date range and specific inclusion criteria.The noise exposure experiment was conducted using a verified phone app to record the sound levels. They were measured at 3 times, during a night shift, in the paediatric emergency department of UHW. All measurements were at a fixed distance and were averaged and compared with WHO recommendations.Results/ConclusionsThere are many sources of noise pollution in the ED, some are unavoidable for safety and clinical reasons.The literature review produced a small number of papers all of which found that sound levels were raised above recommended levels. Similarly, all the sounds measured in the ED also exceeded the recommendations.The most consistent finding across the papers, matched by findings from recordings, was that human behavioural modification is an easy and effective way to reduce noise levels.There are simple steps that can be taken to reduce and eliminate soundsRaising awareness regarding this problem is of great importance and focussing future work on assessing the impact in younger patients within the Emergency Department is paramount.

A Discussion of Pod Drives and Their Application In the Pleasure Boat Market

2009 ◽  
Author(s):  
Christopher Swanhart
Keyword(s):  
North America ◽  
General Information ◽  
Low Noise ◽  
Noise Levels ◽  
Propulsion Systems ◽  
Fully Integrated ◽  
Operator Interface ◽  
Performance System ◽  
Hull Forms

Since being introduced to North America at the Miami Boat Show in 2005, Volvo Penta Inboard Performance System, or IPS has established itself as a leading propulsion choice among pleasure boat owners and builders. Other suppliers are following suit including the Cummins Mercruiser Zeus system. Pod propulsion offers benefits like increased efficiency, better performance, nimble handling, and low noise levels while allowing more people to successfully operate their vessel due to a friendly operator interface. Features of these commercial pod systems that also benefit builders include ease of installation and the integral underwater exhaust which helps to meet CE requirements, for both exhaust and noise levels. Both IPS and Zeus are fully integrated pod propulsion systems. Existing vessels can be retro-fitted with these systems while many new vessels are being designed specifically for IPS or Zeus. Donald L. Blount and Associates provides consulting in regards to IPS integration with existing and new designs and has also been involved with designs employing the Zeus system. The first portion of this paper discusses pod drives, particularly IPS itself. (Because the author has substantially more experience and background with IPS, much of the information herein is IPS specific). General information on IPS and Zeus is offered as well as some operational specifics. The paper then focuses on the application of pod drives in existing and new vessel designs. The discussion includes how hull forms can be evaluated for use with pod drives. A look at the integration of pod systems into various types of pleasure boats (cruiser, day boat, fishing yacht, etc) is also covered including the challenges which exist for each specific vessel type.

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