Thesis (M.Eng.)(Mechanical)--University of Pretoria, 2004. / Includes summary. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 282-288).

Doktorarbeit--Fakultät für Maschinenbau--Ruhr-Universität Bochum, 1989.

Akademisk avhandling--Uppsala, 1995. / Résumé en allemand. Bibliogr. p. 180-189. Index.

Introduction: Each year in the United States, Salmonella enterica infections cause an estimated 1.2 million illnesses that result in 19,000 hospitalizations and 390 deaths. Illnesses occur sporadically throughout the year, but might also occur as part of an outbreak. Outbreaks are most commonly linked to a food source, but contact with live animals can also result in human outbreaks of illness. Methods: Outbreaks of Salmonella reported to the Centers for Disease Control and Prevention through National Outbreak Reporting System (NORS) from 2009–2014 with a primary mode of transmission listed as animal contact or food were analyzed to characterize the demographics of zoonotic outbreaks and examine how they differ from foodborne outbreaks. Missing data for age or sex categories were recoded as age or sex unknown. Chi-square tests were conducted to compare proportions of categorical variables. Logistic regression was used to calculate odds ratios for age, sex, health outcomes and multistate exposure. Wilcoxon rank-sum tests were used to compare medians for outbreak size and duration. Analyses were conducted using SAS 9.3. Results: During 2009–2014, a total of 484 outbreaks were reported through NORS; of these, 99 (20.5%) resulted from Salmonella transmission through animal contact and 385 (79.5%) resulted from foodborne transmission. These outbreaks resulted in 3,604 (19.8%) and 13,568 (80.2%) illnesses, respectively. A higher proportion of outbreak-associated illnesses among children aged(15.2% vs. 1.4%, p Conclusions: Outbreaks of Salmonella resulting from animal contact frequently have characteristics that are distinct from food outbreaks. Findings are consistent with reports in the literature where young children are disproportionately affected by animal contact outbreaks. Animal contact outbreaks might have a higher proportion of hospitalizations, emergency room visits, and healthcare provider visits. Animal contact outbreaks might also be longer in duration and are more likely to be multistate. Future investigations of multistate Salmonella outbreaks that are consistent with these differences should collect epidemiologic information regarding animal exposures to determine if contact with animals resulted in the transmission of the outbreak.

Greater demands are being placed on the separable connector to perform with higher reliability in harsher automotive environments. Corrosion in its various forms is a major mechanism which affects contact reliability and this current work focuses on surface oxidation and the related phenomenon of fretting corrosion, from which hot dipped tin (HDT), a common automotive connector coating, is known to suffer. For an in-depth study of high contact resistance, in both static conditions and when subjected to relative micromovement, an interdisciplinary approach was necessary, drawing on the results of published work carried out in the fields of contact and surface science, corrosion and tribology.

77 p. / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-01-10T20:39:17Z No. of bitstreams: 1 bbbbb123.pdf: 718592 bytes, checksum: 0d80aff4cafb030b788144dfd227a999 (MD5) / Made available in DSpace on 2013-01-10T20:39:17Z (GMT). No. of bitstreams: 1 bbbbb123.pdf: 718592 bytes, checksum: 0d80aff4cafb030b788144dfd227a999 (MD5) Previous issue date: 2008 / Este estudo teve como objetivo geral investigar se os operadores de uma empresa de contact center em Salvador estão acometidos pelo sofrimento em Burnout. Tal propósito se justifica em razão da representatividade econômica e social do setor. Esta empresa disponibiliza cerca de 50.000 postos de trabalho diretos, ocupados principalmente por jovens do sexo feminino em seu primeiro emprego. Como alicerces da fundamentação teórica desta pesquisa, foram adotadas a psicodinâmica do trabalho dejouriana e o pensamento maslachiano, devido à possibilidade de articulação entre as teorias e os dados empíricos. A pesquisa classificou-se como um estudo de caso, de caráter exploratório. A análise dos dados foi feita por meio de pesquisa de campo realizada com a aplicação do questionário de avaliação em Burnout, contendo 22 perguntas. Participaram da pesquisa 129 colaboradores da empresa de nome fictício Contact e, destes, 21,7% encontram-se acometidos pela síndrome. Os resultados encontrados nas entrevistas realizadas com 10,7% dos operadores acometidos por este sofrimento psíquico permitem observar a presença equilibrada de comprometimento nos três fatores que constituem a síndrome: a exaustão emocional, a despersonalização e a realização profissional. Com este estudo, conclui-se que o Burnout está mais relacionado com o tipo de atividade desenvolvida pelos operadores do que com fatores organizacionais, pois os depoimentos demonstrados revelam principalmente a baixa tolerância no contato direto com os consumidores e a falta de identificação com o trabalho. / Salvador

Dans cette thèse, nous développons une méthode locale de type "mortar" pour traiter le problème de contact avec maillages incompatibles de manière optimale dans un code de calcul par éléments finis de niveau industriel. Dans la première partie de la thèse, nous introduisons le cadre mathématique de la méthode intitulée "Local Average Contact" (LAC). Cette approche consiste à imposer la condition de non-interpénétration en moyenne sur chaque élément d'un macro-maillage défini de manière idoine. Nous commençons par développer une nouvelle technique de preuve pour démontrer l'optimalité des approches de type inéquation variationnelle discrétisée par éléments finis standards pour le problème de Signorini, sans hypothèse autre que la régularité Sobolev de la solution du problème continu. Puis nous définissons la méthode LAC et démontrons, à l'aide des nouveaux outils techniques, l'optimalité de cette approche locale modélisant le contact unilatéral dans le cas général des maillages incompatibles. Pour finir, nous introduisons la formulation mixte équivalente et démontrons son optimalité et sa stabilité. Dans la seconde partie de la thèse, nous nous intéressons à l'étude numérique de la méthode LAC. Nous confirmons sa capacité à gérer numériquement le contact unilatéral avec maillages incompatibles de manière optimale à l'instar des méthodes "mortar" classiques, tout en restant facilement implémentable dans un code de calcul industriel. On montre ainsi, entre autres, que la méthode passe avec succès le patch test de Taylor. Finalement, nous montrons son apport en terme de robustesse et au niveau de la qualité des pressions de contact sur une étude de type industrielle. / In this thesis, we develop a local "mortar" kind method to deal with the problem of contact with non-matching meshes in an optimal way into a finite element code of industrial level. In the first part of the thesis, we introduce the mathematical framework of the Local Average Contact method (LAC). This approach consists in satisfying the non-interpenetration condition in average on each element of a macro-mesh defined in a suitable way. We start by developing a new technique for proving the optimality of variational inequality approaches discretized by finite elements modeling Signorini problem without other hypothesis than the Sobolev regularity of the solution of the continuous problem. Then we define the LAC method and prove, using the new technical tools, the optimality of this local approach modeling the unilateral contact in the general case of non-matching meshes. Finally, we introduce the equivalent mixed formulation and prove its optimality and stability. In the second part of the thesis, we are interested in the numerical study of the LAC method. We confirm its ability to optimally treat the contact problem when considering non-matching meshes like standard "mortar" methods, while remaining easily implementable in an industrial finite element code. We show, for example, that the method successfully passes the Taylor patch test. Finally, we show its contribution in terms of robustness and at the quality of the contact pressures on an industrial study.

No description available.

The compression of typical glass fibre woven fabrics, namely plain, twill, satin, and noncrimped stitch-bonded fabric, was studied experimentally by performing a series of mechanical tests on dry and resin impregnated assemblies of fabrics. This was followed by microstructural studies of corresponding laminates cured under different degrees of compression. The experiments included investigations on the effects of applied pressure, speed of compression, fabric orientation, number of plies and different resin systems on fibre volume fraction,Vf, of the compressed assembly. It was found that the compression of dry fabrics followed a power-law relationship between pressure and Vf where the power law index, b, was determined to be approximately equal to 10.3, 9.8 and 9.1 for assemblies consisting of plain, twill and 5 harness satin weaves, respectively. A mathematical analysis was performed for the viscoelastic compression of resin impregnated assemblies of fabrics and a model was developed incorporating the deformation of the fibre network and resin flow through the reinforcement. A methodology was devised for the geometrical representation of plain weaves in the microstructural analysis of cured laminates. The microstructural studies then provided data for the area and geometrical parameters of the yam cross-section; the mean amplitude, wavelength and phase angle of the yarn waveform and the distance between plies at different compression pressures. Cross-sections of laminates with each of the considered fabrics were compared in terms of fibre area fractions, porosity and void content, for the different compression pressures. The aim for the microstructural analysis was to elucidate the mechanism of compression and to follow the development of fibre and pore structure under different degrees of compression. It was concluded that the compression of resin impregnated woven fabrics could be considered as a combination of four modes of deformation; (a) the elimination of a resin rich interlayer between adjacent layers of fabric; (b) the nesting of layers of fabric by slipping while under compression; (c) the deformation of the yam waveform which results in the reduction of thickness of individual plies and (d) the compression and deformation of the cross-sections of individual yarns.