Thesis (M.P.H.) - University of Queensland, 2004. / Includes bibliography.

Proefschrift--Delft. / "Stellingen": 5 p. laid in. Includes bibliographical references.

No description available.

The primary goal of this two-phased, sequential mixed-methods study was to discover whether union affiliation is associated with a lower occurrence of burnout in factory workers by comparing union and nonunion workers. The objective was to determine levels of burnout in union and nonunion employees as well their perception of social support in the workplace. The theoretical synthesis consisted of conservation of resources theory and the theory of reasoned action. The Oldenburg Burnout Inventory (OLBI) and the Quality of Worklife Questionnaire were used to identify the characteristics of the workplace (job demands and job resources) and the level of burnout. Quantitative results confirmed the presence of burnout in both sample populations. Regression results for union participants identified both poor management and increased in job demands as significant predictors of burnout. Conversely, regression results for nonunion participants pointed to poor management only as a significant predictor of burnout. Qualitative descriptive and explanatory thematic results provided additional contextual support for the quantitative findings - specifically, that both union and nonunion participants identified management as a primary concern. In addition, union participants also identified manpower and support as primary concerns in the work environment. The findings point to the negative consequences of burnout for the employer and employee and to areas of concern that need to be addressed in the employment setting. Implications for positive social change include the development of programs to minimize the development of burnout and increase an employee's organizational commitment.

Many adults in the United States experience posttraumatic stress disorder (PTSD) within their lifetimes. Researchers have identified compassion fatigue (CF), which debilitates mental health providers as a result of being exposed to their clients' traumatic experiences, as an occupational hazard. The purpose of this study was to examine whether a correlation exists between the presence of CF and the level of resilience. A confidential survey using the Connors-Davidson Resilience Scale, the Professional Quality of Life Scale Version 5, and a demographic questionnaire were given to graduate-level mental health clinicians who self-identified as routinely working with and/or treating trauma victims in the past 6 months. Participants were recruited from the New England Society for the Treatment of Trauma and Dissociation, the Metropolitan Atlanta Therapists Network, Dallas Chapter NASW listserv, and the Georgia Therapist Network. A multivariate analysis on the collected data was conducted to determine whether a relationship exists between the resilience scale and the subscales of CF within these population samples. According to study findings, there is a correlation between resilience and the 3 compassion fatigue subscales---CF, burnout, and compassion satisfaction. This study may lead to positive social change by helping guide clinicians to find ways to enhance resilience, and therefore, decrease risks of CF.

In previous studies truncated models were found to underestimate the air's upward velocity when compared to wind tunnel velocity studies, which may affect particle aspiration estimates. This work compared aspiration efficiencies using three torso geometries: 1) a simplified truncated cylinder; 2) a non-truncated cylinder; and 3) an anthropometrically realistic humanoid body. The primary aim of this work was to (1) quantify the errors introduced by using a simplified geometry and (2) determine the required level of detail to adequately represent a human form in CFD studies of aspiration efficiency. Fluid simulations used the standard k-epsilon turbulence models, with freestream velocities at 0.2 and 0.4 m s-1 and breathing velocities at 1.81 and 12.11 m s-1 to represent at-rest and heavy breathing rates, respectively. Laminar particle trajectory simulations were used to determine the upstream area where particles would be inhaled. These areas were used to compute aspiration efficiencies for facing the wind. Significant differences were found in vertical velocity and location of the critical area between the three models. However, differences in aspiration efficiencies between the three forms was less than 6% over all particle sizes, indicating that there is little difference in aspiration efficiency between torso models.

Thesis (Ph. D.)--University of Oregon, 2002. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 383-408). Also available for download via the World Wide Web; free to University of Oregon users.

Recent occupational health studies have focused on dermal exposure at the hands, but have been unable to accurately express dose without knowing the HSA. There is no standard method to calculate HSA, though some researchers have derived HSA formulas based on dimensions from a Taiwanese population. This research paper describes a shortcut method to estimate the hand surface area (HSA) of a human hand from a two-dimensional hand tracing, and repeated a Taiwanese HSA study in order to explore the viability of its HSA formula in an American university population. A sample of nine adult men and nine adult women, each representing one third of the population percentile in hand length and hand breadth, were selected from a population within the University of South Florida in Tampa, FL. Hand length, breadth, a 2D hand tracing and a 3D light hand scan were collected from each participant. A linear regression was used to analyze the data sets and found a correlation (R=0.94) between 2D HSA and 3D HSA and slope of 2.6 (SD=0.2), with a regression equation of Y=2.6(X). A paired t-test was used to compare the Taiwanese HSA formula data against the 3D HSA. Results found that the Taiwanese data sets were significantly different from the 3D HSA (p<0.001), averaging 57 cm2 less than the 3D HSA. A jackknife analysis was implemented on the 2D HSA hand tracing data, and a paired t-test was performed between the jackknife estimate predictions and 3D HSA. Mean differences were not significantly different (p=0.97), with 0.87 cm2 difference between means. Results indicate that the USF Hand Tracing Method will provide a better estimate of HSA than the Taiwanese method, and can be used as a tool in HSA estimation.

The overall goals of this doctoral dissertation are to provide knowledge of workers' exposure to nanomaterials and to assist in the development of standard methods to measure personal exposure to nanomaterials in workplace environments. To achieve the first goal, a field study investigated airborne particles generated from the weighing of bulk carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. This study also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood and biosafety cabinet) for control of exposure to particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured with direct-read instruments, and particle morphology was determined by electron microscopy. Sanding of CNT-epoxy nanocomposites released respirable size airborne particles with protruding CNTs very different in morphology from bulk CNTs that tended to remain in clusters (>1µm). Respirable mass concentrations in the operator's breathing zone were significantly greater when sanding took place in the custom hood (p <0.0001) compared to the other LEV conditions. This study found that workers' exposure was to particles containing protruding CNTs rather than to bulk CNT particles. Particular attention should be placed in the design and selection of hoods to minimize exposure. Two laboratory studies were conducted to realize the second goal. Collection efficiency of submicrometer particles was evaluated for nylon mesh screens with three pore sizes (60, 100 and 180 µm) at three flow rates (2.5, 4, and 6 Lpm). Single-fiber efficiency of nylon mesh screens was then calculated and compared to a theoretical estimation expression. The effects of particle morphology on collection efficiency were also experimentally measured. The collection efficiency of the screens was found to vary by less than 4% regardless of particle morphology. Single-fiber efficiency of the screens calculated from experimental data was in good agreement with that estimated from theory for particles between 40 and 150 nm but deviated from theory for particles outside of this range. New coefficients for the single-fiber efficiency model were identified that minimized the sum of square error (SSE) between the experimental values and those estimated with the model. Compared to the original theory, the SSE calculated using the modified theory was at least threefold lower for all screens and flow rates. Since nylon fibers produce no significant spectral interference when ashed for spectrometric examination, the ability to accurately estimate collection efficiency of submicrometer particles makes nylon mesh screens an attractive collection substrate for nanoparticles. In the third study, laboratory experiments were conducted to develop a novel nanoparticle respiratory deposition (NRD) sampler that selectively collects nanoparticles in a worker's breathing zone apart from larger particles. The NRD sampler consists of a respirable cyclone fitted with an impactor and a diffusion stage containing eight nylon- mesh screens. A sampling criterion for nano-particulate matter (NPM) was developed and set as the target for the collection efficiency of the NRD sampler. The sampler operates at 2.5 Lpm and fits on a worker's lapel. The cut-off diameter of the impactor was experimentally measured to be 300 nm with a sharpness of 1.53. Loading at typical workplace levels was found to have no significant effect (2-way ANOVA, p=0.257) on the performance of the impactor. The effective deposition of particles onto the diffusion stage was found to match the NPM criterion, showing that a sample collected with the NRD sampler represents the concentration of nanoparticles deposited in the human respiratory system.

Porous polyurethane foam was evaluated as a potential replacement substrate for the eight nylon meshes currently being used in the diffusion stage of the Nanoparticle Respiratory Deposition (NRD) Sampler. A semi-empirical particle deposition model and preliminary tests were used to select the dimensions of foam substrate needed to match the collection of the NRD sampler at recommended sampling conditions. The foam substrate consisted of a cylinder nominally 25-mm diameter by 40 mm in depth, housed in a conductive plastic cassette cowl (internal diameter of 23 mm) compatible with the existing NRD sampler. Pristine foam was evaluated for metals content via acid-assisted microwave digestion and inductively coupled plasma-optical emissions spectroscopy (ICP-OES) chemical analysis. Foam collection efficiency was evaluated using salt (NaCl) and metal fume test aerosols in independent tests. Foam collection efficiency was compared to the nanoparticulate matter (NPM) criterion (established to reflect the total deposition in the human respiratory system for particles smaller than 300 nm) and theoretical modeling. The collection efficiency of NaCl particles was similar to the NPM criterion (R2 = 0.98) and the model underestimated the experimental efficiency (R2 = 0.38). Increased collection efficiency of metal fume was observed for particles larger than 70 nm presumably due to increased interception effects of fractal shaped particles. The pressure drop across the pristine foam was 1/12th that of the nylon meshes. Foam and nylon meshes were loaded with metal fume particles to evaluate performance under simulated field conditions. Changes in collection efficiency and pressure drop were used as measures of performance. Foam had substantially lower changes in collection efficiency and pressure drop with ~ 19 mg metal fume loaded compared to the nylon meshes with ~ 3 mg metal fume loaded.