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A Dissertation Submitted to the Faculty of Science University of the Witwatersrand, Johannesburg for the Degree of M aster of Science November 1987

"Heat treating is the controlled heating and cooling of a material to achieve certain mechanical properties, such as hardness, strength and the reduction of residual stresses. Many heat treating processes require the precise control of temperature over the heating cycle. Typically, the energy used for process heating accounts for 2% to 15% of the total production cost. The objective of this work is to develop a comprehensive furnace model by improving the current Computerized Heat Treatment Planning System (CHT) based furnace model to accurately simulate the thermal profile of load inside the furnace. The research methodology was based on both experimental work and theoretical developments including modeling different types of heat treat furnaces. More than 50 experimental validations through case studies using the current CHT model were conducted in 11 manufacturing locations to identify the specific problems in the current model. An enhanced furnace model based on Knowledge Data Discovery (KDD) technique and neural network is developed and validated. The new model takes into account the real time furnace parameters determined from the experimental data and accounts for furnace deterioration and some of the complex gradients and heating patterns that exist inside the furnace that is difficult to model. "

A especialidade de Prótese Buco-Maxilo-Facial é responsável por reconstruções complexas da face e do crânio. Entretanto, com a utilização de impressões convencionais, é difícil se alcançar uma adequada adaptação clínica para a reabilitação do paciente. Assim, algumas vêzes, faz-se necessária a obtenção de modelos tridimensionais (3D) que reproduzam a realidade clínica. O objetivo deste estudo é comparar os protótipos obtidos com diferentes protocolos de aquisição de imagem provenientes de distintos aparelhos de tomografia computadorizada com relação à rugosidade superficial, área reconstruída e dose de exposição gerada, procurando estabelecer o mais adequado para a confecção de protótipos de crânio. Para isso, nove protótipos de um fragmento craniofacial seco foram confeccionados. A comparação entre os protótipos quanto à lisura superficial e à área reconstruída foi realizada por meio da Análise de Variância (ANOVA). Nos casos em que a avaliação indicou diferença significativa, foi aplicado como complemento o Teste de Comparações Múltiplas de Tukey. O nível de significância adotado foi de 5%. Em relação à análise de rugosidade as diferenças encontradas não demonstraram correlação com a área reconstruída. Já em relação aos diferentes protocolos, diferenças significativas foram observadas nos protótipos com respeito à área reconstruída e dose de radiação gerada. Pode-se concluir, frente aos resultados encontrados, que as imagens geradas pelos tomógrafos de feixe cônico e feixe em leque, utilizando os protocolos com as resoluções máximas estudadas, estão indicadas para a confecção de protótipos. Contudo, o que deve nortear a seleção do melhor protocolo tomográfico deve ser o propósito da indicação clínica correlacionado com o princípio ALARA (As Low As Reasonably Achievable). / Oral-maxillo-facial prosthodontics is the study of complex face and skull reconstructions. In view of the insufficient degree of adjustment of conventional impression to enable proper clinical rehabilitation, among other reasons, practitioners increasingly resort to 3D models that accurately reproduce the clinical reality. The aim of this study is to determine the optimal selection of imaging device and protocol for use in skull prototyping. The surface roughness and reconstructed area of nine prototypes obtained from a dried craniofacial specimen using different image acquisition protocols and CT devices were measured, in addition to measurements of the radiation dose potentially received by the patient. ANOVA of the surface roughness, reconstructed area and radiation dose data enabled statistical comparisons among the prototypes. Where significant differences were found, Tukey’s multiple-comparison test was conducted, using a significance level of 5%. No correlation was found between surface roughness and reconstructed area. However, significant differences in reconstructed area and radiation dose were found among the different protocols. These results support the use of images generated by CBCT or fan beam CT for the construction of prototypes, using the protocols with the highest resolution. Nevertheless, the selection of the most appropriate TC protocol should be based on the particular clinical indication along with the ALARA (as low as reasonably achievable) principle.

The primary objective of this study was to assess cognitive functioning in participants with relapsing remitting multiple sclerosis (RRMS) using the MicroCog and to compare their performance to that of a demographically matched, healthy control group. It was hypothesized that as a group, participants with RRMS would have worse cognitive function than healthy controls on all Level 1, 2, and 3 Index scores of the MicroCog. Twenty-six participants with RRMS and twenty-nine sex and education matched healthy controls were administered the MicroCog (Standard Form) along with measures of depression and clinical status, and paper-pencil tests of processing speed (Symbol Digit Modalities Test; SDMT and Paced Auditory Serial Addition Test; PASAT). A series of ANCOVAs with depression as a covariate was performed to determine between group differences for each MicroCog Level 3 Index score (General Cognitive Proficiency (GCP) and General Cognitive Functioning (GCF)), Level 2 Index score (Information Processing Accuracy (IPA) and Information Processing Speed (IPS)), and Level 1 Index score (Attention/Mental Control, Memory, Reasoning/Calculation, Spatial Processing, and Reaction Time). Pearson's and point biserial r correlations were calculated in order to assess the degree to which Level 2 and 3 Index scores correlated with clinical and demographic factors (sex, disease duration, depression, and clinical status) and to correlate the MicroCog IPS index score with traditional measures of processing speed. Eight RRMS and two control participants met criteria for cognitive impairment on the MicroCog. ANCOVA results indicated there were significant differences between RRMS and control performance for two MicroCog scores (GCF and IPS). There were not significant differences for GCP, IPS, and all Level 1 scores. A post-hoc analysis performed for the same hypothesis with a group of age equivalent participants suggested a significant RRMS by depression interaction for Level 3 scores. RRMS was not predictive of Level 2 scores after controlling for depression in the age equivalent sample. Correlations for clinical and demographic factors with cognitive outcomes indicated significant relationships for clinical status and depression. There was not a significant relationship detected for disease duration or sex. MicroCog and processing speed measures were significantly related. Post-hoc analyses supported that the criterion validity of the MicroCog is comparable to other cognitive screening tools in RRMS. The results and limitations of our study are discussed, in addition to recommendations for future research.

The advantages of administering an adaptive test battery, a collection of multiple adaptive subtests that are specifically tailored to examinees’ abilities, include shortening the subtest length and maintaining the accuracy of individual subtest scores. The test battery can incorporate a range of subjects, though this study focused primarily on Math and Reading. This study compared different ways of incorporating collateral information (CI), supplementary information beyond examinees’ current test performance, under two frameworks (Unidimensional and Multidimensional computerized adaptive testing). It also investigated the impact of subtest intercorrelations (the relationship between an examinee’s test scores), as well as the sequences of subtest administration on ability estimation in a variable-length adaptive battery. Practical issues including content constraints and item exposure control were also considered. Findings showed that the CI methods improved measurement efficiency with an acceptable level of measurement precision. The CI was more beneficial when associated with higher intercorrelations among the subtests. Also, the CI was found to be advantageous during the early stages of the subtests which were not taken first. Therefore, the CI may improve the examinee experience by administering items more aligned with their abilities. In addition, the CI should reduce costs for testing organizations by requiring fewer items and possibly saving seat time, while still providing reliable scores. The results should help practitioners decide whether the use of the CI is worthwhile under their particular testing situation.

Training paraprofessionals who work with children with Autism Spectrum Disorder and other related developmental disabilities can be a challenge due to limited resources, time, and money. Alternative ways to train paraprofessionals on a larger scale is needed. Interactive computerized training—a self-paced program that incorporates audio narration, video models, interactive activities, and competency checks—is one potential training method. Interactive computerized training has been successful at training college students and special education teachers to implement discrete trial instruction but their effectiveness in training paraprofessionals is unknown. The purpose of this study was to extend the literature on interactive computerized trainings to evaluate its utility to teach six paraprofessionals to implement discrete trial instruction. Errorless learning procedures are recommended during discrete trial instruction to minimize student errors and promote quicker skill acquisition. A secondary purpose was to evaluate the effectiveness of the interactive computerized training to teach paraprofessionals to implement an errorless learning procedure. Following the training, all participants increased their fidelity of implementation of discrete trial instruction, at varying levels, with a student in their classroom. One participant reached the performance criterion of 90% or higher fidelity following ICT alone and two participants required performance feedback. Three participants required live coaching to increase their fidelity of DTI components to 80%. All feedback was delivered from a distance. Fidelity remained high to untrained instructional programs and at 2-week follow up. Potential limitations and future research related to training paraprofessionals are discussed.

<p>The aim of this study was to evaluate if a population suffering from generalized anxiety disorder could benefit from an Internet based self-help treatment guided via email contact with a therapist. The treatment was based on established cognitive behavioral principles. It was hypothesized that significant improvements would be found as measured by eight self report questionnaires, absence of a clinical diagnoses and global clinical improvement. A total of 89 participants were included and 44 were randomized to a treatment condition and 45 were assigned to a waitlist control. The controls received similar treatment after the first post treatment assessment, conducted eight weeks after the beginning or treatment of the first group. The results showed statistically significant improvements for the treatment group. No changes were observed in the waiting-list control group, with the exception of a minor decrease in depression scores. Large effect sizes were found both within the treatment group and between the two groups in favor of the treatment. In conclusion, Internet treatment can be an efficacious format for treating generalized anxiety disorder.</p>

Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 26, 2007) Includes bibliographical references.