Thesis (M.S.)--University of Akron, 2004. / Title from Web page (viewed on Dec. 17, 2007). "December, 2004." Includes bibliographical references (p. 118-124).

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Anette M. Karlsson, Dept. of Mechanical Engineering. Includes bibliographical references.

Graduation date: 2002

Background - Communicable respiratory illness is a serious occupational threat to healthcare workers. A key reason for occupational transmission is failure to implement appropriate barrier precautions. Facial protective equipment, including surgical masks, respirators and eye/face protection, is the least adhered to type of personal protective equipment used by healthcare workers, yet it is an important barrier precaution against communicable respiratory illness. Objectives - To describe nurses’ adherence to recommended use of facial protective equipment and to identify the factors that influence adherence. Methods - A two-phased study was conducted. Phase 1 was a cross-sectional survey of nurses in selected units of six acute care hospitals in Toronto, Canada. Phase 2 was a direct observational study of critical care nurses. Results – Of the 1074 nurses who completed surveys (82% response rate), 44% reported adherence to recommended use of facial protective equipment. Multivariable analysis revealed four organizational predictors of adherence: ready availability of equipment, regular training and fit testing, organizational support for health and safety, and good communication. Following the survey, 112 observations in 14 intensive care units were conducted that showed a 44% competence rate with proper use of N95 respirators. Common gaps included failure to verify the seal and touching the face piece. Multivariable analysis revealed knowledge of recommended use of facial protective equipment as a significant predictor of competence. Discussion – Despite the SARS experience and the resulting investment in our public health system, nurses’ adherence to recommended use of facial protective equipment and competence in effective use of N95 respirators remains suboptimal. To improve adherence, organizational leaders should focus on equipment availability, training and fit testing, organizational support for health and safety, and positive communication. To improve competence in effective use of N95 respirators, strategies to increase knowledge should be implemented. These efforts should assist to reduce occupational transmission of communicable respiratory illness and foster a healthier and safer working environment for nurses.

Protective clothing is widely used in many industries and applications to provide protection against fire exposure. Exposure to fire can result in skin burn injuries that range from first-degree to third-degree burn injury depending on the exposure intensity and duration. Within the firefighting community, and especially the petroleum and petrochemical industries flash fire is one of the possible fire hazards for workers. Exposure to flash fire is usually of short duration (a few seconds) until the worker runs away from the fire location. The typical protective clothing system consists of a fire resistant fabric, the human skin, and an air gap between the fabric and skin. The protective performance of the clothing is evaluated based on the total energy transfer from the fabric to the skin through the air gap causing burn injury to the skin. Therefore the air gap between the protective clothing and skin plays an important role in determining the protection level provided by the clothing since the energy transfer through the air gap determines the amount of energy received by the skin. The more realistic the analysis of the air gap, the more reliable the evaluation of the protective performance of the clothing. This study introduces a more realistic analysis for the air gap between protective clothing and the skin compared to that found in the literature. More specifically, the study accounts for the combined conduction-radiation heat transfer through the air gap, which was treated as a thermal radiation participating medium with temperature dependent thermophysical properties. A finite volume model was developed to simulate the transient heat transfer in a single layer protective clothing system with radiation heat transfer. The model was employed to investigate the influence of the conduction-radiation heat transfer through the air gap on the overall heat transfer through the protective clothing system and hence on its protective performance. The influence of different protective clothing parameters on the combined conduction-radiation heat transfer through the air gap such as the air gap absorption coefficient, air gap width, fabric thickness, and fabric backside emissivity was studied. A comprehensive study of the influence of a periodic variation in the air gap width and associated inflow of cool air due to the motion of the person wearing the clothing on its protective performance was carried out. A wide range of variation in the frequency and amplitude of the fabric periodic movement was considered to capture different scenarios for the wearers motion. Finally, a finite volume model was developed to simulate the transient heat transfer in multiple layers firefighters protective clothing. The model considered the combined conduction-radiation heat transfer in the air gaps entrapped between the clothing layers, which were treated as thermal radiation participating media. The influence of each air gap on the overall performance of the clothing was investigated as well. The improved air gap model is a significant improvement for modeling heat transfer in protective clothing. It was used to obtain a more detailed knowledge of the theoretical performance of such clothing, e.g. it was found that reducing the fabric backside emissivity was more effective in improving the clothing protective performance than increasing the fabric thickness. It was also observed that the motion of the person wearing the clothing has a significant effect on the performance of the clothing: an increase in the frequency of the fabric movement improves the protection provided by the clothing, primarily due to the more frequent inflow of cool air, while an increase in the amplitude of the fabric movement reduces the protection provided by the clothing by concentrating the exposure on the skin. Finally, the air gaps entrapped between the clothing layers in firefighters protective clothing were found to improve the clothing performance, and the influence of the air gap between the moisture barrier and the thermal liner is greater than that of the air gap between the outer shell and the moisture barrier.

Protective clothing is widely used in many industries and applications to provide protection against fire exposure. Exposure to fire can result in skin burn injuries that range from first-degree to third-degree burn injury depending on the exposure intensity and duration. Within the firefighting community, and especially the petroleum and petrochemical industries flash fire is one of the possible fire hazards for workers. Exposure to flash fire is usually of short duration (a few seconds) until the worker runs away from the fire location. The typical protective clothing system consists of a fire resistant fabric, the human skin, and an air gap between the fabric and skin. The protective performance of the clothing is evaluated based on the total energy transfer from the fabric to the skin through the air gap causing burn injury to the skin. Therefore the air gap between the protective clothing and skin plays an important role in determining the protection level provided by the clothing since the energy transfer through the air gap determines the amount of energy received by the skin. The more realistic the analysis of the air gap, the more reliable the evaluation of the protective performance of the clothing. This study introduces a more realistic analysis for the air gap between protective clothing and the skin compared to that found in the literature. More specifically, the study accounts for the combined conduction-radiation heat transfer through the air gap, which was treated as a thermal radiation participating medium with temperature dependent thermophysical properties. A finite volume model was developed to simulate the transient heat transfer in a single layer protective clothing system with radiation heat transfer. The model was employed to investigate the influence of the conduction-radiation heat transfer through the air gap on the overall heat transfer through the protective clothing system and hence on its protective performance. The influence of different protective clothing parameters on the combined conduction-radiation heat transfer through the air gap such as the air gap absorption coefficient, air gap width, fabric thickness, and fabric backside emissivity was studied. A comprehensive study of the influence of a periodic variation in the air gap width and associated inflow of cool air due to the motion of the person wearing the clothing on its protective performance was carried out. A wide range of variation in the frequency and amplitude of the fabric periodic movement was considered to capture different scenarios for the wearers motion. Finally, a finite volume model was developed to simulate the transient heat transfer in multiple layers firefighters protective clothing. The model considered the combined conduction-radiation heat transfer in the air gaps entrapped between the clothing layers, which were treated as thermal radiation participating media. The influence of each air gap on the overall performance of the clothing was investigated as well. The improved air gap model is a significant improvement for modeling heat transfer in protective clothing. It was used to obtain a more detailed knowledge of the theoretical performance of such clothing, e.g. it was found that reducing the fabric backside emissivity was more effective in improving the clothing protective performance than increasing the fabric thickness. It was also observed that the motion of the person wearing the clothing has a significant effect on the performance of the clothing: an increase in the frequency of the fabric movement improves the protection provided by the clothing, primarily due to the more frequent inflow of cool air, while an increase in the amplitude of the fabric movement reduces the protection provided by the clothing by concentrating the exposure on the skin. Finally, the air gaps entrapped between the clothing layers in firefighters protective clothing were found to improve the clothing performance, and the influence of the air gap between the moisture barrier and the thermal liner is greater than that of the air gap between the outer shell and the moisture barrier.

Background - Communicable respiratory illness is a serious occupational threat to healthcare workers. A key reason for occupational transmission is failure to implement appropriate barrier precautions. Facial protective equipment, including surgical masks, respirators and eye/face protection, is the least adhered to type of personal protective equipment used by healthcare workers, yet it is an important barrier precaution against communicable respiratory illness. Objectives - To describe nurses’ adherence to recommended use of facial protective equipment and to identify the factors that influence adherence. Methods - A two-phased study was conducted. Phase 1 was a cross-sectional survey of nurses in selected units of six acute care hospitals in Toronto, Canada. Phase 2 was a direct observational study of critical care nurses. Results – Of the 1074 nurses who completed surveys (82% response rate), 44% reported adherence to recommended use of facial protective equipment. Multivariable analysis revealed four organizational predictors of adherence: ready availability of equipment, regular training and fit testing, organizational support for health and safety, and good communication. Following the survey, 112 observations in 14 intensive care units were conducted that showed a 44% competence rate with proper use of N95 respirators. Common gaps included failure to verify the seal and touching the face piece. Multivariable analysis revealed knowledge of recommended use of facial protective equipment as a significant predictor of competence. Discussion – Despite the SARS experience and the resulting investment in our public health system, nurses’ adherence to recommended use of facial protective equipment and competence in effective use of N95 respirators remains suboptimal. To improve adherence, organizational leaders should focus on equipment availability, training and fit testing, organizational support for health and safety, and positive communication. To improve competence in effective use of N95 respirators, strategies to increase knowledge should be implemented. These efforts should assist to reduce occupational transmission of communicable respiratory illness and foster a healthier and safer working environment for nurses.

Among many useful properties of elastomers, one is their ability to absorb energy by deforming to large strains without fracturing. This property combined with their good adhesion to substrates makes them suited as adhesive films and coatings for protection against impact damage. An example of practical significance is the erosion of helicopter rotor blades where the protection of leading edge is often achieved by mounting a film or applying a coat of polyurethane. Although this is a workable solution, there is currently little knowledge as to the durability of this elastomeric film/coat under impact of hard and angular particles such as sand. A deformation and failure analysis that deals with the angularity of the erodents and captures the local mechanisms responsible for erosion damage in elastomers is the sine qua non. The present endeavor tries to address these issues by considering a polyurethane layer on a quasi-rigid substrate, impacted by hard particles at velocities and angles of attack given by pre-specified distributions. A novel method is devised to address the angularity issue. A series of finite-element calculations are performed on the coating layer-substrate systems subjected to different velocities, incidence and angularity of the impacting erodents. An elasto-plastic material constitution with isotropic hardening is employed in the simulations and material parameters representative of polyurethane are used for the coat. Initial parametric deformation analyses provided an adequate qualitative estimate of erosion parameters. Incorporation of a stress based fracture criterion enabled a quantitative measure of material removal due to erosion to be achieved. The simulation results show good match with experimental trends of target mass loss as obtained under normal and inclined loadings with angular erodents. The current simulation framework has sufficient capability and versatility to incorporate more enriched polymer-models and advanced fracture criteria in the future, thereby allowing parametric studies toward selection of materials and coat-layer thicknesses thus predicting the erosion mass loss as accurately as measured by experiments.

The objective of this thesis is to enhance the reliability analysis of Relaying systems and build-up model by Markov theory for taipower transmission lines. The set of combinatory multi-elements can be expressed a transition matrix for any pilot protection analysis. The protective reliability system need for transmission protection is introduced and the block modeling consists of protective relays, communication set and circuit breaker. The block modeling is applied for the analysis of the reliability and availability of protection systems by Markov theory, which can be need to derive the adapative maintance cycle by Markov reliability modeling. The system reliability is analysis related to the interruption of supply power. There many methods to be used for the analysis of system reliability such as state space, network. etc. The Markov modeling is more complicated and difficult, however better time-vary probability functions can be defined, for stochastic modeling, the system reliability at any time axis can be obtained by Markov transition matrix, with the time-vary Markov transition matrix. The customers served by each substation can be affected according to the states of transmission lines healthy. Althouth 80% of system faults occurs in the distribution system, transmission line faults will cause more serious service outage. According to the Kauo-Ping transmission line model in taipower, the optimal protection relay planning is solved by minimizing the overall outage cost of customer service interruption and investment protection relay equipments for transmission power systems with immune algorithm. The objective function and constraints are expressed as antigen, and all feasible solutions are expressed as antibody. The diversity of antibody is then enhanced by proximity of antigen so that the global optimization during the solution process can be obtained. It is found that the power service can be restored effectively with the optimal planning of protection relay by the proposed immune algorithm. Based on the computer simulation of protection relay planning, different protection relaying strategies optimal relay planning and customer loss, can be considered for different to enhance the reliability of protection relay system for loss interruption of customer power outage.

Abstract In order to determine whether antigens prepared from adult intestine of Angiostrongylus cantonensis have potential to induce a protective immunity in the rodent hosts, somatic antigens extracted from male and female adults as well as gut antigens isolated from female adults were used to immunize rats against A. cantonensis infection. A 14% reduction in L5 recorvery from brain as well as a 15% reduction in adult recovery from pulmonary artery were achieved in the immunized rats when compared with the control group after infection with 50 larvae. The length of worms recovered from immunized rats was shorter than that in other groups. The larvae recovered from fecal materials in immunized rats were also reduced. In cell proliferation test, the stimulation index of gut antigens increased with times of immunization and exhibited the highest values. However, serum IgG titers were not correlated with protective immune responses. A 84 kDa protein contained in all antigen preparations was recognized by immune serum against gut antigens. Strong positive reactions were detected by indirect immunofluorescent assay in the internal musculature of the body, gut and reproductive tract wall and gut lumen. The composition of gut antigens was similar to that of gut membrane proteins. Immune sera recognized several major gut proteins were also appeared on gut membrane proteins. Further studies are required to provide evidence that gut membrane proteins play in the protective immune response against A. cantonensis infections, including the 84 kDa protein.