The primary objectives of this research were to determine the macroscopic properties of polycrystalline OFHC copper for various grain sizes over a wide range of strain rates and temperatures, and to relate the properties to the fundamental microscopic mechanisms which control the deformation characteristics of the material....

The purpose of this thesis is to assess and develop a non-destructive evaluation (NDE) procedure for evaluating the integrity of rectangular and square reinforced concrete (RC) slabs. This procedure employs both dynamic frequency and deformation response signatures to track changes in the slab following dynamic excitation. Such a procedure could provide a good basis for practising engineers to conduct nondestructive testing (NDT) and evaluation of general RC structures. The response of RC floor slabs to dynamic excitation have been experimentally studied at 1/3rd scale for two aspect ratios (square and rectangular), three concrete grades, and with and without cement replacement under clamped edge conditions. The model slabs were subjected to series of quasi-static loading and unloading sequences, to increasing load levels until failure was reached. At the unloaded part of each load cycle, the slabs were subjected to dynamic excitations, alternately using a hand-held, Bruel and Kjaer (B and K) impact hammer, and broad-band burst chirp shaker excitation. For the larger square slabs, at each unloaded part of the load cycle, a 265 gm steel ball bearing dropped from a fixed, standard height to provide more robust impulse excitation. All of the slabs were instrumented with optimally located accelerometers and strain gauges to capture the slab responses. The acceleration, deflection and strain readings resulting from the dynamic excitation were recorded at incremental load steps, from the initial unloaded state up to failure, and subsequently evaluated and analysed. The results show that the changes resulting from damage are readily observable, in the fundamental and higher modes of vibration and in the load-deflection and strain responses. These changes have been examined and analysed in both the time and frequency domains, and using other techniques, to establish the viability of this approach in evaluating the integrity of RC and other complex structures.

In society, individuals tend to be socialized into roles that take on characteristics of masculine and feminine. Studies exist on the role strain experienced by heterosexual couples dealing with a life-threatening illness due to this characterization. The scholarly literature lacks studies on the understanding of roles, as well as possible role strain, in lesbian, gay, bisexual, transgender, and queer (LGBTQ) couples when dealing a life-threatening illness. The purpose of this qualitative case study was to explore the role strain experiences of LGBTQ couples who are living with cancer diagnoses of a partner. Biddle's role strain theory provided the conceptual framework for this study. The study included interviewing five LGBTQ couples with a partner having a first-time diagnosis of Stage II or III cancer. Face-to-face, individual, semistructured interviews were used to collect the data, and an open coding method to analyze the data. The themes identified were the significance of fluid roles prior to cancer diagnoses, adjustment to role change, relationship since cancer diagnoses, chosen or determined roles, and society's views of roles. Finding were LGBQT couples roles were chosen or determined based on the task they enjoy or like to do instead of stereotypical view of masculine and feminine. LGBTQ couples did not report experiencing role strain related to assuming additional roles due to their partners' illness. Positive implications for social change resulted from the ability to inform healthcare providers how LGBTQ couples manage when supporting a partner diagnosed with Stage II or Stage III cancer.

The use of carbon nanotubes (CNTs) as a material for construction of sensors is a promising effort. This is due to some unique characteristics of CNTs. In recent years, strain sensors built from CNT composite films have been developed. This thesis study first proposed that the piezoresistive sensitivity of CNT composite films can be limited due to the presence of one of the constituent elements in the CNT composite films, that is, surfactant. CNT films free of surfactants were thus hypothesized to have a great promise to improve piezoresistive sensitivity. The motivation of this thesis study was to explore this promise.<p> This thesis presents an experimental study on Single-Wall CNT (SWNT) films free of surfactants. Such SWNT films are called pure SWNT films. The study has concluded: (1) the gauge factor of one layer SWNT film is much higher than that of CNT composite film; (2) the fabrication of multilayered pure CNT films is highly possible; (3) the gauge factor of multilayered pure SWNT films (10 layers and 0.8mg/ml concentration) can reach as high as 2.59 with non-linearity of 0.89% and repeatability of 0.1%, which outperforms the strain sensor built from CNT composite films; (4) the role of surfactants is indeed restrictive to piezoresistive response, and (5) the junction theory is likely applicable to pure SWNT film sensors.<p> The main contributions of this thesis study are: (1) the finding of a new type of strain sensors built from pure CNT films and (2) the development of a fabrication process for multilayered pure SWNT films.

The use of carbon nanotubes (CNTs) as a material for construction of sensors is a promising effort. This is due to some unique characteristics of CNTs. In recent years, strain sensors built from CNT composite films have been developed. This thesis study first proposed that the piezoresistive sensitivity of CNT composite films can be limited due to the presence of one of the constituent elements in the CNT composite films, that is, surfactant. CNT films free of surfactants were thus hypothesized to have a great promise to improve piezoresistive sensitivity. The motivation of this thesis study was to explore this promise.<p> This thesis presents an experimental study on Single-Wall CNT (SWNT) films free of surfactants. Such SWNT films are called pure SWNT films. The study has concluded: (1) the gauge factor of one layer SWNT film is much higher than that of CNT composite film; (2) the fabrication of multilayered pure CNT films is highly possible; (3) the gauge factor of multilayered pure SWNT films (10 layers and 0.8mg/ml concentration) can reach as high as 2.59 with non-linearity of 0.89% and repeatability of 0.1%, which outperforms the strain sensor built from CNT composite films; (4) the role of surfactants is indeed restrictive to piezoresistive response, and (5) the junction theory is likely applicable to pure SWNT film sensors.<p> The main contributions of this thesis study are: (1) the finding of a new type of strain sensors built from pure CNT films and (2) the development of a fabrication process for multilayered pure SWNT films.

The Strain Index was originally designed to analyze mono-task jobs. An experiment using a grip dynamometer was used to simulate six multiple task jobs to study the effect of complex tasks on localized muscle fatigue and to evaluate six different models used to calcula te a Complex Strain Index score. These models included average Strain Index score, unadjusted summation, duration adjusted summation, complex equation, minimum intensity, and peak intensity. Two methods of calculating a continuous Strain Index score were also analyzed. Ratings of perceived exertion, hand and forearm fatigue and discomfort, Difficulty Rating, maximum voluntary contraction (MVC), and percent strength loss were recorded for each of the six treatments. Electromyography (EMG) was also recorded for the 24 subjects (12 males and females) who completed the experiment. The EMG signal was analyzed using root mean square (RMS), initial mean power frequency (IMnPF), and slope of the mean power frequency (MnPF). Each treatment, lasting one hour each, contained a primary exertion (Task 1) of either 10% or 40% MVC for three seconds and a secondary exertion (Task 2) of either 10% or 40% MVC for one or three seconds. Subjective variables linearly increased (R2 > 0.88) over the duration of the treatments and significantly differed between treatments (p < 0.05). Percent strength loss was the only variable with a gender effect (p < 0.05). RMS values did not indicate fatigue and were constant over each treatment, but were highly correlated with percent MVC. A significant difference was not found in IMnPF between pre and post treatment values or between treatments (p > 0.05). A significant difference was found for MnPF slope pre and post treatment, but no treatment effect was found (p > 0.05). The complex equation method of calculating a Strain Index score was the only model of the six evaluated that met all criteria for being an acceptable method of calculating a Complex Strain Index score. The two continuous methods presented for calculating a Strain Index score should not be used for job analysis until further research evaluates their reliability, validity, and critical scores for Hazard Classification.

We have studies the II-VI ternary compound semiconductor ZnSe grown by molecular beam epitaxy ¡]MBE¡^Method. The modulation spectroscopy was used to study ZnSe. ZnSe epilayer was grown on GaAs substrate. The lattice mismatch¡]0.27 ¢H¡^between GaAs and ZnSe create a strain at the GaAs/ZnSe interface. The strain will remove the degeneracy of heavy and light holes to conduction band transition energies. We use the photoreflectance to measure the energy of different thickness ZnSe epilayers at low temperature. It was found that as the epilayer thickness becomes larger, the£GE will become smaller. We have also analyzed the energy of different temperatures in terms of Varshni relation, and the temperature dependence of the broadening parameters.

The work of this thesis includes molecular beam epitaxy (MBE) and optical study of strained InGaAs and InGaAlAs multiple quamtum well (MQW) structures. Two strained layer structures suitable for devices applications have been designed, grown, and investigated. The first one is a 0.98-

Innovation on human-machine interfacing technologies is critical for the development of smart, multifunctional and efficient electronic/optoelectronic systems. The effect of piezotronics is a newly started field of study, which utilizes piezoelectric polarization that is mechanically induced inside a piezoelectric semiconductor to regulate electron transport across electronic contact interfaces. With the concept coined in 2006, many efforts have been contributed to studying the underlying physical mechanism of this effect as well as demonstrating various applications based on single nanowire piezotronic devices. This thesis selects ZnO as the material foundation and was started by firstly studying flexible, controllable and scalable synthesis methods for ZnO nanowires array and thin film. By replacing the use of random, individual nanowires with these materials, novel piezotronic and piezophototronic devices were designed, fabricated and tested to achieve the function of strain sensing, tactile imaging, piezo-enhanced photodetection and solar energy harvesting. The adoption of nanowires array and thin film materials over single nanowires leads to significant advantages in terms of scalable fabrication, industrial compatibility and broader functionality. By consistently going down this route, we believe that the field of piezotronics will eventually make revolutionary impact on MEMS, optoelectronics, multifunctional sensor networks, human-machine interfacing and so on.

The goal of this research was to develop and test a self-completed questionnaire for use in the routine assessment of work-related stress in a high-technology industrial organization. The initial phase of the study involved reviewing the existing literature to identify items and scales developed to assess workplace stress and strain. The initial item pool contained 92 items divided into 11 domains. Through a process of content validation using focus group discussions, the item pool was reduced to a 38-item questionnaire covering eight domains: demands, control, support, role, relationships, rewards, change, and communications. These 38 items, along with other items included to enable psychometric testing, were converted to a web-based questionnaire. The entire workforce of the organization was invited to complete this questionnaire as part of the pilot study phase.Data from the pilot study were used to test scaling assumptions, evaluate the factor structure, estimate internal consistency reliability, and examine criterion and construct validity of the 38-item Workplace Climate Questionnaire. The distribution of responses to questionnaire items tended to be skewed, with more respondents scoring among the more positive categories. With the exception of the role and relationships scales, no substantial floor and ceiling effects were seen for all the other scales. Each of the 38-item Workplace Climate Questionnaire scales exhibited satisfactory internal-consistency reliability estimates. Items within the demands, control, support, and role scales loaded on the hypothesized scales, while items within the relationships, change, and rewards failed to load on the hypothesized scales.The pilot study provided support for criterion validity of the 38-item Workplace Climate Questionnaire. As hypothesized, individual scales in the questionnaire correlated positively with similar constructs in existing occupational stress instruments. The pilot study also provided support for construct validity of the questionnaire. The demands, control, support, relationships, rewards, and change scales predicted the risk of poor self-reported mental health.Revisions to the 38-item questionnaire resulted in the 22-item Workplace Climate Questionnaire covering the following six domains: demands, control, role, rewards, support, and relationships. The 22-item questionnaire reduces respondent burden and retains satisfactory psychometric properties in terms of factor structure, reliability, criterion validity, and construct validity.