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In this dissertation, the problem of using accelerated degradation testing data for reliability estimation is studied and demonstrated. Simulation and analytical approaches have been investigated. By simulation which generates a large number of degradation paths, the reliability estimate of the product can be estimated using an empirical formation. This approach is general and has a great flexibility in estimating the reliability of a product regardless of the functional form of the degradation paths. However, it is time-consuming and sometimes can not provide efficient and accurate reliability estimates. Alternatively, the analytical approach may provide the closed-form expressions for reliability estimates for specific degradation process models. If the model fits, this approach is more accurate and efficient than the simulation approach. More importantly, when the closed-form solution exists, the optimal design of testing plans can be formulated and solved with the objective of either improving the accuracy of the reliability estimate or the accuracy of the economic loss. In addition to the statistical study of the reliability estimation, the optimal design of Accelerated Degradation Testing (ADT) plans has been investigated extensively. The objectives considered include minimizing the variance of single reliability estimate for the maintenance requirement, minimizing the weighted variances of multiple reliability estimates and minimizing the weighted economic loss associated with the reliability estimates considering multiple maintenance requirements. In the literature, this work is the first study regarding the optimal design of testing plans that considers maintenance requirements. By determining the optimal setting of decision variables such as the stress levels in the ADT experiments, the improvements in these objectives have been demonstrated using numerical examples. It can be seen that the novel methodology developed in this dissertation can significantly reduce the uncertainty of certain indices associated with the reliability estimates. This work is important in the area of reliability engineering as it indicates an efficient way of conducting accelerate degradation testing to verify the product's reliability and make management decisions under limited testing resources. / Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering. / "December 2006." / Includes bibliographic references (leaves 126-132)

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The study investigated the antecedents to disposition to trust with regard to the Accelerated Reader program. The areas considered were teachers’ experience, teachers’ peer experience, teachers’ peer support, gender, and age. The population for this study consisted of teachers who used Accelerated Reader from four school districts in Louisiana. The total number of teachers who were given the survey was 417, and the number of teachers who completed the survey was 301, resulting in a response rate of 72.2%. In this study, 6 research questions were addressed. The first question asked whether a statistically significant relationship exists between teachers’ experience in using electronic education tools and their disposition to trust Accelerated Reader technology to facilitate reading instruction. The second question asked if a statistically significant relationship exists between teachers’ peer experience and their disposition to trust Accelerated Reader software technology to improve reading instruction. The third question asked if a statistically significant relationship exists between teachers’ peer support and their disposition to trust that Accelerated Reader software technology improves reading instruction. The fourth question asked if a relationship exists between teachers’ gender and their disposition to trust that the Accelerated Reader technology will improve reading instruction. The fifth research question asked if a statistically significant relationship exists between teachers’ age and their disposition to trust that the Accelerated Reader technology will improve reading instruction. Finally, the sixth research question asked if teachers trust that Accelerated Reader technology is perceived as effective in helping to improve reading instruction. The results found that teachers’ experience, teachers’ peer experience, teachers’ peer support, and gender were all antecedents that had meaningful statistical relationships with disposition to trust. Gender was found to affect only 1% of the overall variance of disposition to trust when all five variables were examined together; however, findings indicated that females had less disposition to trust than males. Multiple age brackets were found to be insignificant.

This study was needed to determine if the Accelerated Reader (AR) program made a positive impact in schools, which were attempting to increase student achievement in reading. The purpose of this study was to determine if students who received reading instruction supplemented with the AR Program achieved higher reading scores as measured by the Mississippi Curriculum Test (MCT) than students who were instructed using only traditional basal reader textbooks. 6 school districts were selected to participate in this study. There were 1,111 3rd — 5th grade students in the 6 districts between the years 2004 and 2007. Of those 1,111 students, 248 students met the criteria to be included in this study. Therefore, 248 students’ reading scores were analyzed for this study. The findings of the study revealed that AR had a positive impact on students’ MCT reading scores. There were no significant differences, however, between the reading scores in the three years 2004, 2005, and 2006 of AR students (male or female) and the reading scores of the Non-AR (NAR) students (male or female). There were no significant differences between the reading scores in the three years 2005, 2006, and 2007 of the AR students and the reading scores of the NAR students (male or female). This study was needed to determine if the AR program was beneficial to schools, which were attempting to increase student achievement in reading. The findings of this study may be used to help administrators and schools evaluate the usefulness and money spent on AR. While no significant differences were shown, the results did show that the AR students’ scores were higher than the NAR students on the MCT reading.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Magister Pharmaceuticae - MPharm / The objective of the study was to perform a comparative review of pathways, timelines and improvements of countries with markets that the South African Health Products Authority (SAHPRA) benchmark themselves against. Furthermore, this study intends to identify the factors that improved and accelerated submissions and approval process in investigated countries and potential introduction of these strategies into the South African market.

Accelerated aging of 15 kV Cross-linked Polyethylene (XLPE) and Ethylene Propylene Rubber (EPR) power cables was carried out in the experiments set for the study of this thesis. The degradation of cable insulation under different aging conditions was studied and compared. The study helped to understand the effects of different factors on the aging of XLPE and EPR cable insulation. In the study, degradation of XLPE cable insulation caused by switching impulses was investigated. The deterioration of EPR cable insulation initiated by elevated ac voltage and switching impulses were also studied. Measurements of partial discharge parameters, capacitance, and dissipation factor were analyzed to evaluate the condition of cable insulation during accelerated aging process. Measurement of ac breakdown voltage provided evidence of the cables’ remaining dielectric strength after accelerated aging.

Master of Science / Food Science Institute / Elizabeth A. E. Boyle / The market for bison meat products is increasing as a result of consumer interest in meat from animals that are primarily grass fed. Quality attributes of a bison meat snack containing cranberry and apple pieces and formed into a bar or bite were evaluated during 18 weeks of storage in a 40°C accelerated shelf life cabinet to simulate an ambient shelf life of 18 months. The products were formulated at a commercial facility; bars were packaged into a vacuum package, while bites were packaged in a sealed bag with an oxygen absorber. External color, pH, sensory attributes, Warner-Bratzler shear force (WBSF), water activity (a[subscript]w), and yeast and mold populations were determined. External color, pH, and a[subscript]w were evaluated on weeks 0, 3, 5, 12, 14, and 18 of accelerated storage. Sensory attributes, WBSF shear force, and yeast and mold populations were evaluated on weeks 0, 3, 5, 12, and 18. At week 0 and week 18, external L* for the bars and bites were similar (P>0.05); however, trained panelists observed both products becoming visually darker (P<0.05) by weeks 3 and 12 for bars and bites, respectively. For bars and bites, a* values remained constant (P>0.05) through week 5 and 12, respectively, and then became less red (P<0.05) by week 14 for bars and bites. Bars continued to become less red (P<0.05) by week 18. Bar a[subscript]w remained constant (P>0.05) from week 0 through week 18, while bites a[subscript]w remained constant through week 5, and then declined (P<0.05) to a mean a[subscript]w of 0.83 by week 18. Bar pH remained constant (P>0.05) through week 5, and then declined (P<0.05) to 4.32 at week 18. Bites pH declined (P<0.05) from 4.63 at week 0 to 4.22 at week 18. Yeast and mold populations were non-detectable throughout storage for both products. Panelists found that bar bite and tenderness remained similar (P>0.05) from 4.63 at week 0 through week 18. Bites became softer and more tender (P<0.05) from week 0 to week 3, and then remained similar (P>0.05) through week 18. Bars and bites WBSF remained similar (P>0.05) from week 0 through week 18. Bar sweetness and fruit flavor intensity declined (P<0.05) and bar and bite off-flavors increased (P<0.05) by the end of storage. Changing product size from bars to bites and using a vacuum bag versus a sealed bag with an oxygen absorber influenced product characteristics during accelerated storage. The recommended shelf life for bars and bites would be equivalent to 5 months at ambient temperature based on 5 weeks at accelerated storage at 40°C.