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.

[EN] Predicting thermal comfort perceived during wearing protective clothing is important especially for the head as it is one of the most sensitive body parts to heat. Since helmets typically induce an additional thermal insulation that impairs the heat dissipation from the head, a special attention should be drawn to a heat strain leading to a decrease of the cognitive performance and to adverse health effects. Thermal manikins allow systematic analysis of the heat and mass transfer properties of protective clothing. However, this methodology does not provide sufficient information about the local and the whole body human physiological response in different cases of use. The prediction of the physiological state of the body is provided by a thermophysiological model. However, they are not capable of accounting for complex heat and mass exchange processes at the skin surface when the clothing is worn. Thermal devices could measure the overall effect of these processes when wearing the given actual gear and being exposed to the surrounding environment. Several attempts to couple thermal manikins with physiological models have been undertaken, however, the partial coupling of a body part manikin with a physiological model has not been addressed so far. Hence, the aim of this work was to develop a novel thermophysiological human head simulator for headgear evaluation based on the coupling of a thermal head manikin with a thermophysiological model. This method would be able to realistically reproduce the effect of clothing on the heat and mass transfer from the head's skin to the environment. A thermal head manikin with a dedicated segmentation for headgear testing was evaluated for the thermophysiological human head simulator. This head manikin showed consistent when compared to previously published data of a less segmented head manikin and the more detailed investigation of the local heat transfer at head brought additional information regarding the contribution of the local design characteristics of the headgear to the overall heat exchange. The thermal head manikin was evaluated in the most demanding scenarios according to the human physiology. It was possible to consistently define four head parts, namely, forehead, cranial, face and neck parts. When heterogeneous surface temperature distribution was applied on the head manikin, the gradients between head parts could compromise the precision of skin temperature prediction at forehead and face. The passive heating and cooling responsiveness of the head manikin did not present any limitation for simulating sudden temperature step changes. However, when the manikin heating and cooling processes were modulated by the PI control with default settings, the time needed to reach the temperature set point was larger than the time required by the human physiology. The thermophysiological model was validated for prediction of global and local skin temperatures by comparing simulations against human experimental data in a wide range of conditions. The physiological model showed a good precision in general when predicting core and mean skin temperature. A reduced precision was observed for some local skin temperatures. Finally, the thermal head manikin and the physiological model were coupled to build up the thermophysiological head simulator. The comparison of the prediction of the coupled system with human experimental data in several scenarios showed a good agreement for rectal and mean skin temperatures. However, some greater discrepancy was observed for forehead temperature in exposures in which participants were exercising in warm environments. The representation of the human sweat evaporation could be affected by a reduced evaporation efficiency and manikin sweat dynamics. The industry will benefit from this thermophysiological human head simulator, which will lead to the development of helmet designs with enhanced thermal comfort, and therefore, with higher acceptance by users / [ES] Poder predecir el confort térmico durante el uso de indumentaria de protección es muy relevante especialmente en el caso de la cabeza, ya que es una de las partes más sensibles del cuerpo al calor. Los cascos y otros elementos de protección frente a impactos incorporan un aislamiento adicional que di-ficulta la disipación de calor en la cabeza. Los maniquís térmicos permiten analizar de manera sistemática las propiedades de transferencia de calor y humedad de la indumentaria de protección. Sin embargo, esta metodología no permite inferir la respuesta fisiológica del usuario cuando utiliza la prenda. Existen modelos termofisiológicos que permiten predecir la respuesta térmica humana pero presentan algunas limitaciones cuando se representan los procesos de transferencia de calor y humedad a través de la ropa. En este caso, un maniquí térmico podría cuantificar el intercambio real de calor que se pro-duce con el ambiente térmico cuando se viste una determinada prenda. Existen experiencias en las que un maniquí de cuerpo completo ha sido acoplado con un modelo termofisiológico. Sin embargo, el acoplamiento de un maniquí que representa únicamente una parte del cuerpo con un modelo de la fisiología humana no ha sido llevado a cabo hasta ahora. Por lo tanto, el objetivo de este trabajo ha sido desarrollar una nueva metodología para evaluar cascos y equipos de protección para la cabeza basándose en el acoplamiento de un maniquí térmico de cabeza con un modelo fisiológico. Un maniquí térmico de cabeza ha sido evaluado para ser acoplado con un modelo termofisiológico. Sus medidas fueron consistentes con resultados anteriormente publicados realizados con un maniquí en menos seccionado. Este nuevo maniquí introdujo información adicional sobre la contribución en particular de las distintas características de diseño del casco al intercambio de calor global. El maniquí térmico de cabeza fue evaluado en los escenarios más extremos identificados para la fisiología humana. Se pudo identificar cuatro partes en el sistema acoplado, frente, cráneo, cara y cuello. En el caso de simular una distribución heterogénea de temperatura, los gradientes generados entre las diferentes partes podrían comprometer la precisión en la predicción de la temperatura de la piel en la frente y la cara. La capacidad pasiva de calentamiento y enfriamiento del maniquí de cabeza no supuso ninguna limitación para simular los cambios súbitos de temperatura de la piel pero cuando el control PI del maniquí moduló los procesos de calentamiento y enfriamiento, el tiempo necesario para alcanzar la temperatura de consigna fue mayor que el tiempo de reacción observado en la fisiología humana. Las predicciones de temperatura obtenidas con el modelo de la fisiología humana fueron validadas mediante la comparación con datos humanos experimentales. En general, el modelo mostró buena precisión para la predicción de la temperatura interna y la temperatura media de la piel. Sin embargo, la precisión observada fue menor para la predicción de algunas temperaturas locales. El maniquí térmico de cabeza y el modelo termofisiológico fueron acoplados. La comparación de las predicciones del sistema acoplado con datos humanos experimentales en diferentes escenarios mostró concordancia para la temperatura rectal y media de la piel. No obstante, se observó una mayor discrepancia en la predicción de la temperatura de la frente si se comparaba las simulaciones obtenidas con el modelo por sí solo y con el sistema acoplado en escenarios en los que los participantes realizaban actividad física ambientes cálidos. La representación de la evaporación del sudor humano en el sistema acoplado podría estar condicionada por una menor eficiencia en la evaporación y la respuesta dinámica de la sudoración del maniquí. La industria se podrá beneficiar de este sistema para avanzar en el desarrollo de nuevos productos que proporcionen / [CAT] Poder predir el confort tèrmic durant l'ús d'indumentària de protecció es especialment rellevant en el cas del cap, ja que és una de les parts més sensibles del cos a la calor. Els cascs incorporen un aïllament adicional que dificulta la dissipació de la calor al cap. Aquest fet és particularment dramàtic quan l'estrès tèrmic afecta negativament a la funció cognitiva i té efectes negatius sobre la salut. Els maniquins tèrmics permeten analitzar de manera sistemàtica les propietats tèrmiques de la indumentària de protecció. No obstant, aquesta metodologia no permet inferir la resposta fisiològica de l'usuari quan utilitza la indumentària. En l'actualitat existixen models matemàtics que permeten predir l'estat fisiològic del cos humà però presenten algunes limitacions quan es tracta de simular els complexos processos de transferència de calor i humitat que ocorren amb roba. En aquest cas, un maniquí tèrmic podria quantificar l'intercanvi real de calor que es produïx en l'ambient tèrmic quan es porta una determinada roba. Existixen experiències prèvies en les que un maniquí de cos complet ha sigut acoblat en un model de la fisiologia humana. No obstant, l'acoblament d'un maniquí que representa únicament una part del cos en un model de la fisiologia humana no ha sigut dut a terme fins ara. Per tant, l'objectiu d'aquest treball es desenvolupar una nova metodologia per a evaluar cascs i indumentària de protecció per al cap basada en l'acoblament d'un maniquí tèrmic de cap amb un model fisiològic. Un maniquí tèrmic de cap ha sigut valorat per a ser acoplat en un model de la fisiologia humana. Les mesures del maniquí van ser consistents amb els resultats publicats en maniquís menys seccionats. Aquest maniquí tèrmic de cap introduix informació adicional sobre la contribució particular de les dife-rents característiques del disseny dels cascs a l'intercanvi de calor global. El maniquí tèrmic de cap ha sigut valorat en els escenaris més extrems identificats per la fisiologia hu-mana. Es van poder identificar quatre parts al sistema acoblat, front, crani, cara i coll. En el cas de simular una distribució heterogènia de temperatura en la superfície del maniquí de cap, els gradients generats entre les diferents parts podria comprometre la precisió en la predicció de la temperatura de la pell en el front i la cara. La capacitat passiva de calfament i refredament del maniquí de cap no va suposar ninguna limitació per simular els canvis sobtats de temperatura de la pell observats en la fisiologia humana. No obstant, quant el control PI del maniquí modulà els processos de calfament i refredament, el temps necessari per alcançar la temperatura de consigna va ser major que el temps de reacció observat en la fisiologia humana. Les prediccions de temperatura obtingudes en el model de la fisiologia humana previst per formar part del sistema acoblat van ser validades amb dades humanes experimentals. En general, el model va mostrar una bona precisió en la predicció de la temperatura interna i la temperatura mitjana de la pell. No obstant, la precisió va ser menor en la predicció de las temperaturas locals. El maniquí tèrmic de cap i el model de la fisiologia humana van ser acoblats. La comparació de les prediccions del sistema acoblat amb dades humanes experimentals mostraren concordança en el cas de la temperatura rectal i mitjana de la pell. No obstant, s'observà una major discrepància en la predicció de la temperatura del front quant es comparaven les simulacions obtingudes en el model per sí mateix i el sistema acoblat en escenaris en els quals els participants realitzaven activitat física en am-bients càlids. La representació de l'evaporament del suor humà en el sistema acoblat podria estar con-dicionada per una menor eficiència en l'evaporament. La indústria es podra beneficiar d'aquest sistema per a avançar en el desenvolupament de nous productes que proporcione / Martínez Guillamón, N. (2016). Multi-sector thermophysiological head simulator for headgear research [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61487 / TESIS

This diploma thesis is focused on the assessment of the influence of moisture on the thermal properties of the gloves. The first part of the thesis deals with the research of topics related to the given issue as well as with the derivation of the computational relations needed for evaluation of experimental measurements. The main focus of the work lies on defining the hypotheses and experiments that are used to verify the influence of moisture on the thermal resistance of gloves. As for the experimental part, it describes the individual methods of moistening the gloves from which the moistening through the air humidity and the moistening by the immersion were analysed. To verify the suitability of selected moistening methods, the tested glove samples were measured on the thermal manikin both in a dry and a moistened state under the conditions defined by ČSN EN 511 and ČSN EN ISO 15831 standards. Individual states were repeatedly measured and afterwards the progresses of thermal resistance depending on time were graphically displayed. The thesis also includes analysis of measurement uncertainties as well as evaluation of measurement repeatability. From the obtained results, both the defined hypotheses and theoretical assumptions about the decrease of the thermal resistance of a textile material due to the influence of moisture were confirmed in the conclusion of the diploma thesis.

This diploma thesis is focused on determination of thermal properties of gloves by means of thermal manikin. The background research with relation to this topic together with derivation of the computational equations used for the following measurement are presented in the first part. The most significant part of this work is suggestion of procedure for measuring the heat resistance of gloves with thermal manikin based on procedure from ČSN EN 511. This methodics was verificated with 5 pairs of gloves together with analysing the uncertainties and testing the repeatability of this measurement. This work also contains the outline for all of the measured pairs with posibilities of their usage in specific situations and surrounding air temperatures. At the end of this work is mentioned brief summary of achieved results.

Cardiopulmonary resuscitation (CPR) manikins are an educational technology tool employed to train nurses to perform high-quality CPR during real-life cardiac arrest events. However, a gap exists between CPR skills learned in training and those used in real life. The purpose of this quantitative study was to examine how CPR feedback and anxiety in registered nurses affect CPR performance on a manikin. Distributed practice and attentional control theory served as the foundations for this study. The research questions addressed the influence of demographic factors, real-time CPR feedback, and simulated hospital noises on CPR performance using CPR manikins. The study included a randomized longitudinal experimental design. Data were collected from 120 nurses via a demographic questionnaire, the Cognitive and Somatic Anxiety Questionnaire, and CPR compression performance feedback via a Zoll R Series defibrillator. Data analysis involved a repeated measures ANOVA or a regression analysis. Findings indicated that participants’ age predicted CPR performance. Receiving real-time CPR feedback led to a statistically significant improvement in performance, and the introduction of hospital noises did not predict CPR performance. Findings may be used to enhance individual performance of CPR, which may benefit society through improved patient care during cardiac arrest.

Surgical masks are intended to be used to prevent transmission of disease from a health care worker to a patient. Often times, they are relied upon by health care workers for their own protection. In light of recent developments regarding preparation for health care worker response to global infectious diseases such as H1N1 Influenza, health care workers may experience a false sense of security when wearing surgical masks. The goal of this study was to evaluate the filtration efficiency of a double strap tie-on surgical mask. The manufacturer asserts a >95% efficiency with a 0.1 um challenge aerosol under FDA testing procedures. The NIOSH Title 42 CFR Part 84 certification criteria call for testing at a rate of 85 lpm representing a human moderate to heavy work load breathing rate. Three sizes of monodispersed aerosols (polystyrene latex beads: 0.5 um, 1.0 um, 2.0 um) were used. The specific aims were to measure the collection efficiencies of this mask for the various particle sizes. Two tests were performed. In the first, masks were affixed to a dummy head and the edges of the mask were not sealed. In the second, the edges of the masks were sealed to the head using silicone sealant, so all penetration was through the filtering material of the mask. Differences in upstream and downstream particle concentrations were measured. Thus, penetration by leakage around the mask and through the filtering material was measured. The experimental set up involved passing the aerosol from the nebulizer through a diffusion dryer and Kr-85 charge equilibrator ensuring a dry charge neutralized aerosol cloud for detection by a LASAIR particle counter. The analysis revealed that the filtration efficiency for 0.5 um particles ranged from 3% to 43% for the unsealed masks and 42% to 51% for the sealed. For 1.0 um particles, the efficiency was 58% to 75% for unsealed and 71% to 84% for sealed masks. For 2.0 um, the efficiency was 58% to 79% for unsealed masks and 69% to 85% for the sealed masks. The data were statistically significant and indicated that surgical masks were associated with very low filtration efficiency. This suggests that they may be inadequate against airborne viruses and bacteria.

No description available.

No description available.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Steven J. Eckels / The research presents the investigation of personal cooling systems (PCS) and their effects on humans from a thermodynamic perspective. The original focus of this study was to determine the most appropriate PCS for dismounted U.S. Army soldiers in a desert environment. Soldiers were experiencing heat stress due to a combination of interrelated factors including: environmental variables, activity levels, and clothing/personal protective equipment (PPE), which contributed to the buildup of thermal energy in the body, resulting in heat stress. This is also a common problem in industry, recreation, and sports. A PCS can serve as a technological solution to mitigate the effects of heat stress when other solutions are not possible. Viable PCS were selected from the KSU PCS database, expanded to over 300 PCS in the course of this study. A cooling effectiveness score was developed incorporating the logistical burdens of a PCS. Fourteen different PCS configurations were tested according to ASTM F2370 on a sweating thermal manikin. Four top systems were chosen for ASTM F2300 human subject testing on 22 male and 2 female soldiers in simulated desert conditions: dry air temperature = 42.2 ºC, mean radiant temperature = 54.4 ºC, air velocity = 2.0 m/s, relative humidity = 20%. Subjects wore military body armor, helmets and battle dress uniforms walking on treadmills at a metabolic rate of approximately 375-400W. All the PCS conditions showed significant reductions in core temperature rise, heart rate, and total sweat produced compared to the baseline (p<0.05). The expected mean body temperature was higher in the human subjects than expected based on the cooling obtained from the sweating manikin test. Lowered sweat production was determined to be the likely cause, reducing the body’s natural heat dissipation. The ASHRAE two-node model and TAITherm commercial human thermal models were used to investigate this theory. A method to account for fabric saturation from dripping sweat was developed and is presented as part of a new model. This study highlights that the response of the human body is highly complex in high-activity, high-temperature environments. The modeling efforts show the PCS moved the body from uncompensable to compensable heat stress and the body also reduced sweating rates when the PCS was used. Most models assume constant sweating (or natural heat loss) thus the PCS sweat reduction is the likely cause of the higher than expected core temperatures, and is an important aspect when determining the purpose of a PCS.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Steven J. Eckels / The research presents the investigation of personal cooling systems (PCS) and their effects on humans from a thermodynamic perspective. The original focus of this study was to determine the most appropriate PCS for dismounted U.S. Army soldiers in a desert environment. Soldiers were experiencing heat stress due to a combination of interrelated factors including: environmental variables, activity levels, and clothing/personal protective equipment (PPE), which contributed to the buildup of thermal energy in the body, resulting in heat stress. This is also a common problem in industry, recreation, and sports. A PCS can serve as a technological solution to mitigate the effects of heat stress when other solutions are not possible. Viable PCS were selected from the KSU PCS database, expanded to over 300 PCS in the course of this study. A cooling effectiveness score was developed incorporating the logistical burdens of a PCS. Fourteen different PCS configurations were tested according to ASTM F2370 on a sweating thermal manikin. Four top systems were chosen for ASTM F2300 human subject testing on 22 male and 2 female soldiers in simulated desert conditions: dry air temperature = 42.2 ºC, mean radiant temperature = 54.4 ºC, air velocity = 2.0 m/s, relative humidity = 20%. Subjects wore military body armor, helmets and battle dress uniforms walking on treadmills at a metabolic rate of approximately 375-400W. All the PCS conditions showed significant reductions in core temperature rise, heart rate, and total sweat produced compared to the baseline (p<0.05). The expected mean body temperature was higher in the human subjects than expected based on the cooling obtained from the sweating manikin test. Lowered sweat production was determined to be the likely cause, reducing the body’s natural heat dissipation. The ASHRAE two-node model and TAITherm commercial human thermal models were used to investigate this theory. A method to account for fabric saturation from dripping sweat was developed and is presented as part of a new model. This study highlights that the response of the human body is highly complex in high-activity, high-temperature environments. The modeling efforts show the PCS moved the body from uncompensable to compensable heat stress and the body also reduced sweating rates when the PCS was used. Most models assume constant sweating (or natural heat loss) thus the PCS sweat reduction is the likely cause of the higher than expected core temperatures, and is an important aspect when determining the purpose of a PCS.