The Experts below are selected from a list of 215052 Experts worldwide ranked by ideXlab platform
William J Murphy - One of the best experts on this subject based on the ideXlab platform.
-
referee whistles part ii outdoor sound power assessment
Journal of the Acoustical Society of America, 2019Co-Authors: William J Murphy, Stephen M Tasko, Donald S Finan, Deanna K Meinke, Michael G Stewart, James E Lankford, Adam R Campbell, Gregory A FlammeAbstract:Referee whistles have been suggested as a significant contributor to noise-induced hearing loss. Thirteen models of sport whistles were tested for sound power with a 3-m hemispherical array of 19 microphones. The whistler produced nine tweets of low, medium, and high effort with two samples of each whistle model. Sound power levels ranged between 74 and 115 dB re 1 pW. The low, medium, and high effort tweets had average power levels of 85 ± 6 dB, 100 ± 6 dB, and 110 ± 4 dB, respectively. Preliminary Damage-Risk analysis of the whistle impulses yield varied estimates for the allowable number of tweets before auditory Damage might be expected. For the Auditory Hazard Assessment Algorithm, between 4 and 66 tweets may exceed the daily exposure threshold. Based upon the amount of eight-hour equivalent A-weighted energy, approximately 120 to 500 tweets would exceed the daily 85 dBA exposure limit. The directivity of the sound power measurements will also be examined, and Risk of hearing loss will be discussed.Referee whistles have been suggested as a significant contributor to noise-induced hearing loss. Thirteen models of sport whistles were tested for sound power with a 3-m hemispherical array of 19 microphones. The whistler produced nine tweets of low, medium, and high effort with two samples of each whistle model. Sound power levels ranged between 74 and 115 dB re 1 pW. The low, medium, and high effort tweets had average power levels of 85 ± 6 dB, 100 ± 6 dB, and 110 ± 4 dB, respectively. Preliminary Damage-Risk analysis of the whistle impulses yield varied estimates for the allowable number of tweets before auditory Damage might be expected. For the Auditory Hazard Assessment Algorithm, between 4 and 66 tweets may exceed the daily exposure threshold. Based upon the amount of eight-hour equivalent A-weighted energy, approximately 120 to 500 tweets would exceed the daily 85 dBA exposure limit. The directivity of the sound power measurements will also be examined, and Risk of hearing loss will be discussed.
-
referee whistles part i permissible exposures indoors
Journal of the Acoustical Society of America, 2019Co-Authors: Trevor W Jerome, Gregory A Flamme, William J MurphyAbstract:Sound from referee whistles at sporting events is usually relatively short in duration ( 110 dB SPL). Damage Risk criteria (DRC) that categorize potentially harmful sounds are usually meant for either continuous or impulsive noise. These types of whistle sounds are better categorized as impulsive. Measurements were taken of a trained referee using a sample of commercially available whistles in a controlled environment. One microphone was placed at the ear of the referee, and another was placed 1 m in front of the referee. Whistle signals were analyzed with a maximum duration of 450 ms, which would be typical of a sporting event. DRC for these impulsive sounds have been investigated using DRC of A-weighted 8-h energy (LeqA8), and the warned and unwarned conditions of the AHAAH model. Depending on the Risk model used, the numbers of permissible exposures was as low as zero and extended above.Sound from referee whistles at sporting events is usually relatively short in duration ( 110 dB SPL). Damage Risk criteria (DRC) that categorize potentially harmful sounds are usually meant for either continuous or impulsive noise. These types of whistle sounds are better categorized as impulsive. Measurements were taken of a trained referee using a sample of commercially available whistles in a controlled environment. One microphone was placed at the ear of the referee, and another was placed 1 m in front of the referee. Whistle signals were analyzed with a maximum duration of 450 ms, which would be typical of a sporting event. DRC for these impulsive sounds have been investigated using DRC of A-weighted 8-h energy (LeqA8), and the warned and unwarned conditions of the AHAAH model. Depending on the Risk model used, the numbers of permissible exposures was as low as zero and extended above.
-
anticipatory middle ear muscle contractions in Damage Risk criteria
Journal of the Acoustical Society of America, 2018Co-Authors: Gregory A Flamme, William J Murphy, Stephen M Tasko, Kristy K Deiters, Heath G Jones, William A Ahroon, Nate GreeneAbstract:Anticipatory middle ear muscle contractions (MEMC) have been implemented as protective components of Damage-Risk Criteria (DRC) for impulsive noises. However, no studies have shown that anticipatory MEMC are pervasive among humans. This presentation describes a series of studies of the viability of assumed anticipatory MEMC obtained either through classical conditioning or while operating a model gun. Participants were adults with normal hearing, and the conditioning tasks varied on sensory modality and attention. Both between- and within-subjects designs were used. A conditioned response was defined as an MEMC occurring prior to the unconditioned stimulus and when only the conditioning stimulus was presented. These studies do not suggest that anticipatory MEMC should be included in DRC for impulsive noises.
-
comparison of impulse peak insertion loss measured with gunshot and shock tube noise sources
Journal of the Acoustical Society of America, 2014Co-Authors: William J Murphy, Elliott H Berger, William A AhroonAbstract:The National Institute for Occupational Safety and Health in cooperation with scientists from 3M and the U.S. Army Aeromedical Research Laboratory conducted a series of Impulse peak insertion loss (IPIL) tests of the acoustic test fixtures from the Institute de Saint Louis (ISL) with a 0.223 caliber rifle and two different acoustic shock tubes. The Etymotic Research ETYPlugs™ earplug, 3M™ TacticalPro™ communication headset and the dual protector combination were tested with all three impulse noise sources. The spectra, IPIL, and the reduction of different Damage Risk criteria will be presented. The spectra from the noise sources vary considerably with the rifle having peak energy at about 1000 Hz. The shock tubes had peak levels around 125 and 250 Hz. The IPIL values for the rifle were greater than those measured with the two shock tubes. The shock tubes had comparable IPIL results except at 150 dB for the dual protector condition. The treatment of the double protection condition is complicated because th...
-
a case for using a weighted equivalent energy as a Damage Risk criterion for impulse noise exposure
Journal of the Acoustical Society of America, 2012Co-Authors: William J Murphy, Richard L. MckinleyAbstract:Damage Risk criteria (DRCs) for continuous noise rely upon epidemiologic analyses of populations of persons exposed over several years to noise in occupational environments. In 2006, the U.S. Army proposed to update the MIL-STD 1474D to use the Auditory Hazard Assessment Algorithm for Humans (AHAAH) and discontinue using the peak sound pressure level, envelope duration and number of impulses. The National Institute for Occupational Safety and Health has conducted two separate evaluations of the data used to justify the AHAAH methodology and found that the use of the A-weighted equivalent energy LAeq8 was more suitable for the purposes of predicting the effects of temporary threshold shifts (TTS) both in humans and in chinchillas. The LAeq8 method provided best fit for the TTS outcomes and demonstrated the greatest discrimination (ability to predict TTS) when compared to AHAAH, MIL-STD 1474D and two other proposed DRCs. Similarly, LAeq8 was found to give the best-fit and greatest discrimination for the chi...
Kana Kamimura - One of the best experts on this subject based on the ideXlab platform.
-
mechanistic and statistical approaches to predicting wind Damage to individual maritime pine pinus pinaster trees in forests
Canadian Journal of Forest Research, 2016Co-Authors: Kana Kamimura, Sylvain Dupont, Barry Gardiner, Dominique Guyon, Celine MeredieuAbstract:Maritime pine (Pinus pinaster Aiton) forests in the Aquitaine region, southwestern France, suffered catastrophic Damage from storms Martin (1999) and Klaus (2009), and more Damage is expected in the future due to forest structural change and climate change. Thus, developing Risk assessment methods is one of the keys to finding forest management strategies to reduce future Damage. In this paper, we evaluated two approaches to calculate wind Damage Risk to individual trees using data from different Damage data sets from two storm events. Airflow models were coupled either with a mechanistic model (GALES) or a bias-reduced logistic regression model to discriminate between Damaged and unDamaged trees. The mechanistic approach was found to successfully discriminate the trees for different storms but only in locations with soil conditions similar to where the model parameters were obtained from previous field experiments. The statistical approach successfully discriminated the trees only when applied to similar...
-
a review of mechanistic modelling of wind Damage Risk to forests
Forestry, 2008Co-Authors: Barry Gardiner, Stephen J. Mitchell, Kana Kamimura, Heli Peltola, Kenneth E Byrne, Sophie E Hale, Jean Claude RuelAbstract:Summary This paper reviews the current status of mechanistic models for wind Damage Risk assessment, describing model structure, applicability, validation and current limitations. We focus particularly on the hybrid mechanistic/empirical models GALES and HWIND, which have been designed for calculating wind Damage Risk at the stand level within uniform forests and which are the most widely adopted models within the research community. These models have been integrated with different methods for predicting the local wind climate in order to calculate the probability of wind Damage in a number of different countries. We also discuss ongoing modelling work and proposals for future development in order to deal with complex forest structures and to predict the wind Damage Risk of individual trees within stands through the integration of mechanistic Risk models with forest growth and yield models within a geographical information system framework. This kind of model integration will enable spatial representation of tree lists and Damage propagation and allow managers to evaluate the effect of different harvesting and thinning scenarios on the Risk of windthrow of both stands and individual trees within a stand.
-
developing a decision support approach to reduce wind Damage Risk a case study on sugi cryptomeria japonica l f d don forests in japan
Forestry, 2008Co-Authors: Kana Kamimura, Barry Gardiner, Akio Kato, Takuya Hiroshima, Norihiko ShiraishiAbstract:Summary A decision support-based approach has been developed in order to help recommend silvicultural treatments for reducing typhoon wind Damage in Japanese forests. A case study was conducted on three management scenarios (no thinning, light thinning and heavy thinning) for sugi ( Cryptomeria japonica (L.f.) D.Don) stands in Himi, Toyama Prefecture, Japan. The decision support approach integrated models and tools including a mechanistic/empirical wind Damage Risk assessment model ForestTYPHOON, which includes a modifi ed version of the wind Damage Risk model, geographical analysis of the losses and effects of storms, and an airfl ow model, wind atlas analysis and application program. A growth model Silve-no-Mori was linked with ForestTYPHOON to estimate wind Damage Risk over a 50-year period. After assessing the wind Damage Risk, Risk stands were displayed using a geographic information system. In addition, decision tree analysis provided information on stand characteristics related to wind Damage. Approximately 90 per cent agreement was found between the wind Damage assessment using ForestTYPHOON and the outputs of the decision trees. The decision trees showed that top height was the most important stand characteristic and provided a critical top height at which silvicultural treatments need to be modifi ed. If the top height exceeds the critical height, any treatments including thinning should be avoided to minimize wind Damage Risk.
Barry Gardiner - One of the best experts on this subject based on the ideXlab platform.
-
mechanistic and statistical approaches to predicting wind Damage to individual maritime pine pinus pinaster trees in forests
Canadian Journal of Forest Research, 2016Co-Authors: Kana Kamimura, Sylvain Dupont, Barry Gardiner, Dominique Guyon, Celine MeredieuAbstract:Maritime pine (Pinus pinaster Aiton) forests in the Aquitaine region, southwestern France, suffered catastrophic Damage from storms Martin (1999) and Klaus (2009), and more Damage is expected in the future due to forest structural change and climate change. Thus, developing Risk assessment methods is one of the keys to finding forest management strategies to reduce future Damage. In this paper, we evaluated two approaches to calculate wind Damage Risk to individual trees using data from different Damage data sets from two storm events. Airflow models were coupled either with a mechanistic model (GALES) or a bias-reduced logistic regression model to discriminate between Damaged and unDamaged trees. The mechanistic approach was found to successfully discriminate the trees for different storms but only in locations with soil conditions similar to where the model parameters were obtained from previous field experiments. The statistical approach successfully discriminated the trees only when applied to similar...
-
a review of mechanistic modelling of wind Damage Risk to forests
Forestry, 2008Co-Authors: Barry Gardiner, Stephen J. Mitchell, Kana Kamimura, Heli Peltola, Kenneth E Byrne, Sophie E Hale, Jean Claude RuelAbstract:Summary This paper reviews the current status of mechanistic models for wind Damage Risk assessment, describing model structure, applicability, validation and current limitations. We focus particularly on the hybrid mechanistic/empirical models GALES and HWIND, which have been designed for calculating wind Damage Risk at the stand level within uniform forests and which are the most widely adopted models within the research community. These models have been integrated with different methods for predicting the local wind climate in order to calculate the probability of wind Damage in a number of different countries. We also discuss ongoing modelling work and proposals for future development in order to deal with complex forest structures and to predict the wind Damage Risk of individual trees within stands through the integration of mechanistic Risk models with forest growth and yield models within a geographical information system framework. This kind of model integration will enable spatial representation of tree lists and Damage propagation and allow managers to evaluate the effect of different harvesting and thinning scenarios on the Risk of windthrow of both stands and individual trees within a stand.
-
developing a decision support approach to reduce wind Damage Risk a case study on sugi cryptomeria japonica l f d don forests in japan
Forestry, 2008Co-Authors: Kana Kamimura, Barry Gardiner, Akio Kato, Takuya Hiroshima, Norihiko ShiraishiAbstract:Summary A decision support-based approach has been developed in order to help recommend silvicultural treatments for reducing typhoon wind Damage in Japanese forests. A case study was conducted on three management scenarios (no thinning, light thinning and heavy thinning) for sugi ( Cryptomeria japonica (L.f.) D.Don) stands in Himi, Toyama Prefecture, Japan. The decision support approach integrated models and tools including a mechanistic/empirical wind Damage Risk assessment model ForestTYPHOON, which includes a modifi ed version of the wind Damage Risk model, geographical analysis of the losses and effects of storms, and an airfl ow model, wind atlas analysis and application program. A growth model Silve-no-Mori was linked with ForestTYPHOON to estimate wind Damage Risk over a 50-year period. After assessing the wind Damage Risk, Risk stands were displayed using a geographic information system. In addition, decision tree analysis provided information on stand characteristics related to wind Damage. Approximately 90 per cent agreement was found between the wind Damage assessment using ForestTYPHOON and the outputs of the decision trees. The decision trees showed that top height was the most important stand characteristic and provided a critical top height at which silvicultural treatments need to be modifi ed. If the top height exceeds the critical height, any treatments including thinning should be avoided to minimize wind Damage Risk.
Richard L. Mckinley - One of the best experts on this subject based on the ideXlab platform.
-
liaeq100ms an a duration adjusted impulsive noise Damage Risk criterion
Journal of the Acoustical Society of America, 2015Co-Authors: Richard L. MckinleyAbstract:Impulsive noise Damage Risk criteria (DRCs) have been the subject of much debate nationally and internationally for more than 30 years. Several approaches have been used in proposed DRCs including: curves defining exposure based on peak level and A or B duration; auditory hazard units based on the analytical auditory model known as AHAAH; and LAeq metrics based on the equal energy concept. Each of the approaches has positive and negative attributes. One of the issues with LAeq metrics has been the over estimation of hazard with long duration impulses such as those coming from blasts, artillery, large mortars, or shoulder launched missiles. The presentation will describe and discuss the LIAeq100ms impulsive DRC which includes an adjustment based on the A-duration of the impulsive noise and a method of computing protected impulsive noise exposures using impulsive insertion loss data from hearing protectors measured with methods defined in ANSI S12.42.
-
a case for using a weighted equivalent energy as a Damage Risk criterion for impulse noise exposure
Journal of the Acoustical Society of America, 2012Co-Authors: William J Murphy, Richard L. MckinleyAbstract:Damage Risk criteria (DRCs) for continuous noise rely upon epidemiologic analyses of populations of persons exposed over several years to noise in occupational environments. In 2006, the U.S. Army proposed to update the MIL-STD 1474D to use the Auditory Hazard Assessment Algorithm for Humans (AHAAH) and discontinue using the peak sound pressure level, envelope duration and number of impulses. The National Institute for Occupational Safety and Health has conducted two separate evaluations of the data used to justify the AHAAH methodology and found that the use of the A-weighted equivalent energy LAeq8 was more suitable for the purposes of predicting the effects of temporary threshold shifts (TTS) both in humans and in chinchillas. The LAeq8 method provided best fit for the TTS outcomes and demonstrated the greatest discrimination (ability to predict TTS) when compared to AHAAH, MIL-STD 1474D and two other proposed DRCs. Similarly, LAeq8 was found to give the best-fit and greatest discrimination for the chi...
-
a case for using a weighted equivalent energy as a Damage Risk criterion for impulse noise exposure
Journal of the Acoustical Society of America, 2012Co-Authors: William J Murphy, Richard L. MckinleyAbstract:Damage Risk criteria (DRCs) for continuous noise rely upon epidemiologic analyses of populations of persons exposed over several years to noise in occupational environments. In 2006, the U.S. Army proposed to update the MIL-STD 1474D to use the Auditory Hazard Assessment Algorithm for Humans (AHAAH) and discontinue using the peak sound pressure level, envelope duration and number of impulses. The National Institute for Occupational Safety and Health has conducted two separate evaluations of the data used to justify the AHAAH methodology and found that the use of the A-weighted equivalent energy LAeq8 was more suitable for the purposes of predicting the effects of temporary threshold shifts (TTS) both in humans and in chinchillas. The LAeq8 method provided best fit for the TTS outcomes and demonstrated the greatest discrimination (ability to predict TTS) when compared to AHAAH, MIL-STD 1474D and two other proposed DRCs. Similarly, LAeq8 was found to give the best-fit and greatest discrimination for the chinchilla impulse noise exposures. The LAeq8 affords the best sensitivity and specificity for discrimination of potential hazards and has the greatest level of integration with present occupational exposure standards and prospective hearing protection labeling regulations.
Norihiko Shiraishi - One of the best experts on this subject based on the ideXlab platform.
-
developing a decision support approach to reduce wind Damage Risk a case study on sugi cryptomeria japonica l f d don forests in japan
Forestry, 2008Co-Authors: Kana Kamimura, Barry Gardiner, Akio Kato, Takuya Hiroshima, Norihiko ShiraishiAbstract:Summary A decision support-based approach has been developed in order to help recommend silvicultural treatments for reducing typhoon wind Damage in Japanese forests. A case study was conducted on three management scenarios (no thinning, light thinning and heavy thinning) for sugi ( Cryptomeria japonica (L.f.) D.Don) stands in Himi, Toyama Prefecture, Japan. The decision support approach integrated models and tools including a mechanistic/empirical wind Damage Risk assessment model ForestTYPHOON, which includes a modifi ed version of the wind Damage Risk model, geographical analysis of the losses and effects of storms, and an airfl ow model, wind atlas analysis and application program. A growth model Silve-no-Mori was linked with ForestTYPHOON to estimate wind Damage Risk over a 50-year period. After assessing the wind Damage Risk, Risk stands were displayed using a geographic information system. In addition, decision tree analysis provided information on stand characteristics related to wind Damage. Approximately 90 per cent agreement was found between the wind Damage assessment using ForestTYPHOON and the outputs of the decision trees. The decision trees showed that top height was the most important stand characteristic and provided a critical top height at which silvicultural treatments need to be modifi ed. If the top height exceeds the critical height, any treatments including thinning should be avoided to minimize wind Damage Risk.
