Much research has gone into noise-induced hearing loss (NIHL) and the effects of high intensity noise levels on the hearing mechanism of individuals. A study by the National Institutes of Health has established that high intensity sounds can cause hearing damage of either a temporary, or worse, a permanent nature; regardless of the age of the person. While sound levels below 75 decibels are considered comparatively harmless and have been found not to cause any kind of permanent hearing loss; sound levels greater than 85 decibels and regular exposure of approximately 8 hours per day, on an average, has been found to cause permanent loss of hearing (Bulla, 2003). The purpose of this research study was to assess excessive noise exposure of music-oriented nightclub employees, with music playing. Two employees were used as candidates for the purpose of this study, which was conducted on three days during a work week. Data on personal noise exposure was collected using personal noise dosimeters on a server and a promoter. For purposes of the study, a sound level meter was used to collect the noise levels in the working area, and prepare a sound map. The study was conducted in a nightclub in Tampa, Florida, with music playing. Data was collected on Wednesday, Friday, and Saturday. In total, the data was collected over six sampling nights. The data on noise levels was collected for both personal noise data levels and area noise levels during the period of study. In addition to the personal dosimeters, a sound level meter was also used for data collection. The results of this study indicate that noise levels were highest on nights with live entertainment. The days with performance of live entertainment were random and followed no particular order. The highest TWA noise exposure of 97.3 dB, for the server, occurred on Saturday, when a live entertainer performed in the establishment. The highest TWA noise exposure of 94.3 dB, for the promoter, occurred on Wednesday. Using the OSHA PEL and OSHA Hearing Conversation measurement methods, the server was exposed to excessive noise levels, greater than 85 dBA, on every night of the study (6 nights), while the promoter had three exposures that were greater than 90 dBA, using the OSHA PEL method, and exposures greater than 85 dBA on every night of the study, using the OSHA Hearing Conservation method. However, using the ACGIH measurement method, both the Server and the Promoter were exposed to excessive noise levels every night of the study (six nights).

In the presented work we study methods of image deblurring using two images of the same scene with different exposure times, focusing on two main approach categories, the so called deconvolution and non-deconvolution methods. We present theoretical backgrounds on both categories and evaluate their limitations and advantages. We dedicate one section to a comparison of both method categories on test data (images) for which we use a MATLAB implementation of the methods. We also compare the effectiveness of said methods against the results of a selected single- image de-noising algorithm. We do not focus at computational efficiency of algorithms and work with grayscale images only.

No description available.

Thesis (M. Sc. (Nursing Science)) --University of Limpopo, 2017. / Refer to the document

Aims: The aims of this thesis were to describe and gain an understanding of how people who live in the vicinity of wind turbines are affected by wind turbine noise, and how individual, situational and visual factors, as well as sound properties, moderate the response. Methods: A cross-sectional study was carried out in a flat, mainly rural area in Sweden, with the objective to estimate the prevalence of noise annoyance and to examine the dose-response relationship between A-weighted sound pressure levels (SPLs) and perception of and annoyance with wind turbine noise. Subjective responses were obtained through a questionnaire (n = 513; response rate: 68%) and outdoor, A-weighted SPLs were calculated for each respondent. To gain a deeper understanding of the observed noise annoyance, 15 people living in an area were interviewed using open-ended questions. The interviews were analysed using the comparative method of Grounded Theory (GT). An additional cross-sectional study, mainly exploring the influence of individual and situational factors, was carried out in seven areas in Sweden that differed with regard to terrain (flat or complex) and degree of urbanization (n = 765; response rate: 58%). To further explore the impact of visual factors, data from the two cross-sectional studies were tested with structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see wind turbines versus respondents who could not see wind turbines from their dwelling, and respondents living in flat versus complex terrain. Results: Dose-response relationships were found both for perception of noise and for noise annoyance in relation to A-weighted SPLs. The risk of annoyance was enhanced among respondents who could see at least one turbine from their dwelling and among those living in a rural in comparison with a suburban area. Noise from wind turbines was appraised as an intrusion of privacy among people who expected quiet and peace in their living environment. Negative experiences that led to feelings of inferiority added to the distress. Sound characteristics describing the amplitude modulated aerodynamic sound were appraised as the most annoying (swishing, whistling and pulsating/throbbing). Wind turbines were judged as environmentally friendly, efficient and necessary, but also as ugly and unnatural. Being negative towards the visual impact of the wind turbines on the landscape scenery, rather than towards wind turbines as such, was strongly associated with annoyance. Self-reported health impairment was not correlated to SPL, while decreased well-being was associated with noise annoyance. Indications of possible hindrance to psycho-physiological restoration were observed. Conclusions: Wind turbine noise is easily perceived and is annoying even at low A-weighted SPLs. This could be due to perceived incongruence between the characteristics of wind turbine noise and the background sound. Wind turbines are furthermore prominent objects whose rotational movement attracts the eye. Multimodal sensory effects or negative aesthetic response could enhance the risk of noise annoyance. Adverse reactions could possibly lead to stress-related symptoms due to prolonged physiological arousal and hindrance to psychophysiological restoration. The observed differences in prevalence of noise annoyance between living environments make it necessary to assess separate dose-response relationships for different types of landscapes.

Noise-related hearing loss has been listed as one of the most prevalent occupational health concerns in the United States for more than 25 years with approximately 30 million people in the US alone occupationally exposed to hazardous noise according to the Occupational Safety and Health Organization. Many people are aware of some risks the military members take every day being at war, but very few think about the risks of the members on a base located stateside. To this point, not much research has been done on these risks, and even less has been done on the hazardous noise risks these service members are subjected to. These workers typically work many days a week as well as long hours while being around loud noises for extended periods of time. The purpose of this research study was to collect data on personal noise exposure for security forces at multiple locations at MacDill Air Force Base (AFB) to compare the results with the Air Force Occupational and Environmental Exposure Limit (OEEL) of 85 dBA for an 8-hour time weighted average (TWA) and the Occupational Safety and Health Administration’s (OSHA) Permissible Exposure Limit (PEL) of 90 dBA for an 8-hour TWA. Personal noise dosimeters were used for collecting personal noise exposure, and sound level meters were used for collecting area noise exposure. A Lieutenant at MacDill offered the data she was at liberty to divulge on the security forces for this study. Dosimetry testing was done at four locations, and sound level surveys were done at two locations, with one of the locations being tested by both, dosimeters and a sound level meter. The results from this study show that the highest area noise is on the 26 ft Aluminum Boat at the helm with the sirens on while the boat moves at 25 knots with a noise level at 101.2 dBA, and the highest personal noise exposure was at the CATM section with an 8-hour TWA of 108.9 dBA. When taking the Air Force OEEL (>85 dBA) into account, three of the four locations were overexposed to noise hazards using personal noise dosimetry, but only one of the four locations were overexposed to noise hazards using personal noise dosimetry when using the OSHA PEL (>90 dBA).

Every year, twenty-two million workers are exposed to potentially damaging noise at work. Last year, U.S. businesses paid more than $1.5 million in penalties for not protecting workers from noise. (OSHA, 2016). In the United States ten million people have some kind of noise related hearing loss (CDC, 2016) and noise damage to the ear may not be detected until it is great enough to cause hearing impairment. Grounds keeper’s functions consist of a variety of activities that require the use of powered tools such as mowers, riding mowers, leaf blowers, pressure washers, trimmers/edgers and chainsaws. OSHA has stated that “noise is a potential hazard for most jobs that involve abrasive or high-power machinery, impact of rapidly moving parts (product or machinery), or power tools”. (OSHA, 2016) in addition to this, their job is mostly outdoors exposing them to the added noise of traffic, construction and people. The purpose of this research study was to obtain occupational noise exposure data for groundskeepers who use powered equipment to do their job. The groundskeepers who participated in this research study were volunteers and worked in a University campus in the State of Florida. Personal noise dosimeters were used to collect the data in this study. Exposure information was collected over 6 days for 8-hour work shifts during the summer months of the year. Dosimetry was done on a maximum of five groundskeepers per monitoring day, ranging from 1 to 5 employees per day depending on availability. Results of this study indicate that the highest noise exposures occurred on groundskeepers in charge of mowing by means of a riding mower. Results of this study indicate that the highest 8-hr TWA noise exposure for the groundskeepers (GK) 1 and 2 occurred the first day of testing which was a Monday. Using the OSHA PEL measurement method GK1 exposure was 98.5 dBA, GK2 was 97.6 dBA. Using the same measurement method the highest exposure to GK3: 89.2 dBA, occurred on day five of the assessment. For GK4 the highest exposure occurred on the third day of testing with an exposure measurement of 86.1 dBA. GK5 was only assessed one day and his exposure measured at 84.5 dBA. GK6 AND GK7 were evaluated two days and their highest exposures measured at GK6: 89.3 dBA and GK7: 85.7 dBA. Using the OSHA Hearing Conversation Act measurement method, GK1 was exposed to excessive noise levels (>85 dBA as an 8-hr TWA) on five days of the six day assessment period. GK2 was exposed to hazardous noise levels on all four days he was assessed. GK3 and GK4 exceeded the OSHA HCA standard one of the two days they were monitored. GK 5 did not have noise exposure levels above 85 dBA on the day he volunteered for monitoring. GK6 had exposures over 85 dBA on both days he volunteered to be monitored. Finally, GK7 exceeded the 85 dBA limit on one of the two days they volunteered for this study.

Increased use of communication headsets found in various workplaces raises concerns regarding exposure to potentially hazardous noise levels. Current national and international standards specify a wide range of simple and specialized methods for the measurement of sound exposure under communication headsets. However, to date, quantitative data comparing the degree of agreement between the different measurement methods or their relative performance are lacking, and it is not known if occupational health and safety (OHS) or hearing loss prevention (HLP) stakeholders have the necessary training and equipment to integrate them in their daily practice. A three-step study addressing several knowledge gaps on this topic is presented in this thesis. First, a questionnaire survey distributed to OHS and HLP stakeholders has revealed that knowledge of specialized measurement techniques and access to the necessary equipment varies significantly depending on the training of the different professionals. There is therefore reason to specify several methods in measurement standards to meet the specific needs and expertise of the different stakeholders involved. Second, a series of experiments conducted with single and multiple expert participants indicated that the Type 1 artificial ear is not suited for sound exposure measurement with communication headsets, while Type 2 and Type 3.3 artificial ears are in good agreement with the acoustic manikin technique specified in the International standard ISO 11904-2. Finally, laboratory experiments were conducted to test the indirect calculation method proposed in the Canadian standard CSA Z107.56. Results revealed that the calculation method is suitable to identify possible situations of exposure over the regulatory limit (e.g. 85 dBA), but refinements are proposed to improve measurement accuracy. Overall, this thesis provides new knowledge to guide selection of the most suitable methods for the assessment of communication headset exposure taking into account expertise, access to equipment, and field logistic constraints. Results also have direct implications for future revisions of existing measurement standards. Finally, this work could be the basis for detailed guidelines on noise exposure measurements under communication headsets to better inform OHS and HLP professionals and ultimately prevent occupational noise-induced hearing loss.

This study assessed the role of otoacoustic emission screening for the early identification of noise-induced hearing loss in South African mineworkers. Transient otoacoustic emissions and distortion product otoacoustic emissions were recorded in 106 noise exposed mineworkers (212 ears) aged between 20 and 55 years, and in 17 non-exposed novice workers (34 ears) aged between 18 and 29 years. All subjects had normal hearing acuity, otoscopic examinations and immittance measurements. Four otoacoustic emission (OAE) measurements were taken per ear and repeated by a second audiologist for the evaluation of inter-test reliability. Age and number of years of noise exposure was additionally evaluated as well as the specificity and sensitivity of the tests for this population group. In general the OAEs were diminished at four KHz for both the exposed and non-exposed groups. Age was found to be the primary predictor of diminished OAE tracings. Poor inter-test reliability was obtained. These results indicate that further research is required within this population group before OAE testing can be implemented for screening for noise-induced hearing loss. / Dissertation (M (Communication Pathology))--University of Pretoria, 2006. / Speech-Language Pathology and Audiology / Unrestricted

In 2011, the National Association of Schools of Music (NASM) took an official position to recognize the importance of hearing health and injury prevention as a standard for all member-accredited institutions. This is the largest national acknowledgement promoting hearing health and safety within the music discipline and among students seeking a music degree in the United States. The purpose of the study is to describe what conductors (i.e., instructors) of college-based ensembles know about hearing health and the generation of sound intensity levels. The study aimed to describe the 1) current state of conductors’ awareness and knowledge of sound intensity levels, 2) current attitudes of conductors toward learning and sharing knowledge of sound intensity levels, and 3) current teaching practices of conductors in regard to equipment usage (e.g. sound level meter, noise dosimeter, hearing protection devices) relating to sound measurement and exposure. Findings indicate 80.2% of conductors (N = 162, 66% employed by NASM-accredited institutions) agree that sounds generated during ensemble-based instructional activities (EBIAs) in college-level schools of music are capable of harming human hearing, but 24.1% “do not know” if EBIAs they conduct ever exceed sound intensity levels capable of harming human hearing, 54.9% do not know “what services or resources” their home institutions offer/refer to students, 93% are never using a noise dosimeter, 40% have never had an audiology exam, and 70% have never used hearing protection during an EBIA. Conductors have a strong openness to change current teaching practices and inform themselves about hearing health, but few are personally informing and educating their students during the EBIA. The study serves to assist conductors and foster a new dialogue among their students, colleagues, staff, and administrators to revise current curriculum, explore sound measurement technologies, and evaluate current hearing health and safety issues inherent in the practice, performance, and teaching of sound intensity levels generated during EBIAs in college-level schools of music.