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No / Convenient exact closed-form expressions are derived for calculating the bending stiffness of and stresses within loaded cylindrical bonded rubber blocks of circular cross-section. The particular solutions for simple bending, cantilever loading and apparent shear situations are deduced and studied in detail. The shapes of the deformed profiles are discussed and confirmation is provided that the previously adopted assumption of parabolic profiles of the deformed lateral curved surface is only valid for blocks of very small aspect ratio. In simple bending a relationship which is more realistic than those hitherto suggested is derived for the couple required to maintain a specified rotation of the loaded end of the block. In apparent shear an exact expression for the ratio of the true to the apparent shear modulus is derived, and compared with the experimental data. An improved approximate relation is deduced.

Subcontractors in the automotive industry, have a lot of pressure to bring down costs and to deliver products that are effective, optimized and qualitative. The main purpose of this study is to guide and conduct the first step in the project Standard Building Blocks with modular design, within the business area, manual shifter. The project is directly presented by Kongsberg Automotive, a well-known subcontractor of the automotive industry. The aim of the project is to develop a standard manual shifter with modular design containing standard building blocks. Five different components have been selected in the manual shifter for this study. In each component, there are several concepts on how to design that specific component. The target of the study is to evaluate and analyze the concepts and based on the results decide which of the concepts to be standard building blocks. The study identifies, evaluates and analyses the consequences of the project Standard Building Blocks for the chosen concepts. The results from the study show that some concepts have a greater tendency to form standard building blocks when compared to others. In the study it was proven that non-measurable values have the same significance as the measured values. The results also show that the most suitable concepts depends on the customers’ specifications. The consequence analysis presented many consequences of what an implementation of standard building blocks may imply, from the advantages to possible risk elements. Through the consequence analysis the studied company can become more prepared for the future. / Underleverantörerna inom fordonsindustrin har en stor press när det kommer till hålla nere kostnader och att leverera effektiva, optimerade och kvalitativa produkter. Huvudsyftet med studien är att guida och genomföra det första steget i projektet Standard Building Blocks med modulär design, inom affärsområdet, manuella växelreglage. Projektet är direkt framtaget av Kongsberg Automotive, en välkänd underleverantör inom fordonsindustrin. Målet med projektet är att utveckla en standard manuell växelreglage med modulär design innehållande standard building blocks. Fem olika komponenter har valts ut i den manuell växelreglaget för studien. För varje komponent finns det flera koncept hur den specifika komponenten kan designas. Målet med studien är att utvärdera och analysera koncepten och utifrån resultatet avgöra vilka av koncepten som kan bilda standard building blocks. Studien identifierar, utvärderar och analyserar konsekvenser av projektet Standard Building Blocks för de valda koncepten. Resultatet från studien visade att vissa koncept har en större tendens att bilda standard building blocks än andra. I studien blev det bevisat att icke-mätbara värden har lika stor betydelse som uppmätta värdena. Resultatet visade också att de mest lämpade koncepten beror på kundens specifikationer. Konsekvensen analysen presenter många konsekvenser av vad en implementation av standard building blocks kan innebära, från fördelar till eventuella riskfaktorer. Genom konsekvensanalysen kan det studerade företaget bli mer förberedda för framtiden.

Research Doctorate - Doctor of Philosophy (PhD) / Machine learning methods usually represent knowledge and hypotheses using attribute-value languages, principally because of their simplicity and demonstrated utility over a broad variety of problems. However, attribute-value languages have limited expressive power and for some problems the target function can only be expressed as an exhaustive conjunction of specific cases. Such problems are handled better with inductive logic programming (ILP) or relational reinforcement learning (RRL), which employ more expressive languages, typically languages over first-order logic. Methods developed within these fields generally extend upon attribute-value algorithms; however, many attribute-value algorithms that are potentially viable for RRL, the younger of the two fields, remain to be extended. This thesis investigates an approach to RRL derived from the learning classifier system XCS. In brief, the new system, FOXCS, generates, evaluates, and evolves a population of ``condition-action'' rules that are definite clauses over first-order logic. The rules are typically comprehensible enough to be understood by humans and can be inspected to determine the acquired principles. Key properties of FOXCS, which are inherited from XCS, are that it is general (applies to arbitrary Markov decision processes), model-free (rewards and state transitions are ``black box'' functions), and ``tabula rasa'' (the initial policy can be unspecified). Furthermore, in contrast to decision tree learning, its rule-based approach is ideal for incrementally learning expressions over first-order logic, a valuable characteristic for an RRL system. Perhaps the most novel aspect of FOXCS is its inductive component, which synthesizes evolutionary computation and first-order logic refinement for incremental learning. New evolutionary operators were developed because previous combinations of evolutionary computation and first-order logic were non-incremental. The effectiveness of the inductive component was empirically demonstrated by benchmarking on ILP tasks, which found that FOXCS produced hypotheses of comparable accuracy to several well-known ILP algorithms. Further benchmarking on RRL tasks found that the optimality of the policies learnt were at least comparable to those of existing RRL systems. Finally, a significant advantage of its use of variables in rules was demonstrated: unlike RRL systems that did not use variables, FOXCS, with appropriate extensions, learnt scalable policies that were genuinely independent of the dimensionality of the task environment.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 2a).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains viii, 87 p. Includes bibliographical references (p. 85-87). Available online via OhioLINK's ETD Center

L'analyse et la compréhension des mécanismes d'érosion en présence d'un environnement critique au niveau de pression et de température des produits de combustion d'un propergol solide au sein d'une tuyère de moteur fusée, constituent l'objectif principal de ce présent mémoire. Les principaux paramètres, le pourcentage d'aluminium dans l'écoulement, la température adiabatique de flamme.le flux de chaleur en face de la géométrie de l' insert et ses propriétés thermochimiques, sont plus particulièrement étudiés à travers une approche numérique et expérimentale. Le phénomène d'ablation qui se produit au niveau de l' insert d'une tuyère pendant le fonctionnement du moteur propergol solide est ainsi étudié et des résultats d'essais des moteurs à échelle réduite et pleine sont présentés puis simulés numériquement. En effet, les essais mis en place, riches en résultats sur les conditions du matériau de l'insert avant et après le tir, ne permettent pas une analyse complète du développement des mécanismes en jeu au cours du temps de fonctionnement des moteurs. Pour introduire ces phénomènes physiques plutôt complexes, une stratégie de développement progressive est mise en place. Au départ, un modèle 1D a traité les équations de transfert de chaleur utilisant une technique de discrétisation numérique multi-blocs. A partir de la méthode 1D, des expressions simples pour représenter l'évolution des fronts d'ablation et de pyrolyse sont définies.Ces expressions sont alors utilisées de façon directe sur le traitement des problèmes axisymétriques et confrontées avec les simulations du moteur test. Finalement, la méthode aux frontières immergées est appliquée pour traiter du couplage entre l'écoulement et l'insert, mettant en évidence le phénomène d'ablation. Les simulations numériques reproduisent les résultats expérimentaux et montrent une méthodologie numérique robuste, correspondant à des attentes en ce qui concerne l'évaluation du phénomène d'ablation au sein d'une tuyère de moteur fusée. / The main objective of this study is understand the ablation mechanisms in the presence of a critical environment in pressure and temperature within a solid propellant rocket motor. The well-known parameters, aluminum percentage in the flow, adiabatic flame temperature and the consequent heat flux in front of the geometry of the insert and its thermochemical properties are studied from anumerical and experimental strategy. The ablation phenomenon, which occurs at the nozzle insert during the operation of the solid propellant rocket motor, is th us studied and results of tests of the small and full-scale motors are presented as well as numerically simulated. Indeed, tests carried-out provide results on the conditions of the material of the insert before and after firing tests, do not allow is to provide a complete analysis of the development of the mechanisms involved during the running time of the engines. To introduce these rather complex physical phenomena a strategy of progressive development is followed. Initially, a 1D model treated the heat transfer equations using a multi-block numerical discretization technique. From the 1D method, simple expressions to represent the evolution of the ablation and pyrolysis fronts are defined. These expressions are then used directly on the treatment of axisymmetric problems and confronted with simulations of the scale motor. Finally, the immersed boundary method is applied to tackle coupling between flow and heat transfer on the insert, highlighting the phenomenon of ablation. The numerical simulations reproduce the experimental results and show a robust numerical methodology, corresponding to expectations in what concerns the evaluation of the ablation phenomenon within a solid propellant rocket motor nozzle.

Advancements in the medical field with regard to the development of new techniques, reassessment and analyses of the old and unsatisfactory techniques and the expansion and improvement of acceptable techniques have led to an increase in the use of regional anaesthetic nerve blocks in paediatric patients. However, several regional anaesthetic procedures are currently not being performed by anaesthetists due to the high number of complications and difficulties experienced. Some medical practitioners are under the impression that they lack the knowledge and confidence to perform these regional nerve blocks, especially on neonatal and infant patients. In order to assist these doctors in refining their anatomical knowledge and increasing their confidence in performing these nerve blocks, the procedures which are experienced as problematic need to be identified and evaluated. The aim of this study was therefore: (1) to establish the most efficient method of blocking the maxillary nerve within the pterygopalatine fossa; (2) to investigate which head and neck regional nerve blocks are performed most frequently on paediatric patients and identify problem procedures that are performed by practicing anaesthesiologist in South Africa; (3) to develop a clinical anatomy information base for the selected procedures. Three methods / techniques for maxillary nerve blocks were simulated and compared on 24 dry paediatric skulls and 30 dissected paediatric cadavers. The depth and angles at which the needle travels to block the maxillary nerve in the pterygopalatine fossa, after existing the skull through the foramen rotundum, was measured and compared. The method using the supra-zygomatic approach (method B), from the frontozygomatic angle towards the pterygopalatine fossa, exhibited no statistical significance (p > 0.05) when comparing the measurements in the skulls and cadavers. Method A, a supra-zygomatic approach from the midpoint on the lateral border of the orbit, as well as method C, an infra-zygomatic approach with an entry at the site of a vertical line extending along the lateral orbit wall, showed statistical significance when comparing measurements in the skulls and cadavers. It can therefore be concluded that method B produces the most consistent data and should be tested in a clinical setting. Seventeen commonly performed paediatric regional nerve blocks were identified. A detailed questionnaire was completed by 111 respondents, either electronically or from others attending either the Pain Interventions and Regional Anaesthesia Conference or the South African Society of Anaesthesiologists Conference. Difficulties in performing the regional anaesthetic nerve blocks, and complications encountered, were the main areas of focus, when selecting the four problem procedures. The problem procedures selected are the following: supra-orbital and supra-trochlear nerve blocks, infra-orbital nerve block (Extra-oral approach), superior laryngeal and recurrent laryngeal nerve blocks. A detailed anatomical information base was developed through an extensive literature review. This will aid in educating and facilitating doctors in performing paediatric regional nerve blocks, thereby enabling them to successfully practice medicine. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Anatomy / unrestricted

This thesis examines the use of diagonal tension (shear) testing to determine factors affecting shear strength of Interlocking Compressed Earth Block (ICEB) panels. This work expands on the current information available about strength properties of ICEB assemblies, which are dry-stacked, as opposed to having mortared beds. Variables such as block strength, grout strength and grouting pattern can influence the results of these types of tests and are examined in this investigation. To study variables affecting diagonal shear strength, 9 panels were tested, consisting of blocks produced by a manual block press. Strength testing was adopted from common ASTM standards to determine constituent material properties. A modified version of ASTM E519 test procedure is used to perform diagonal tension testing. Imaging analysis, using a high resolution camera, was run simultaneously during testing to capture displacement histories of select panels. It was determined that both block and grout strength significantly affect the shear strength of ICEB panels. Additionally, vertical grouting and block type also have a strong influence. Imaging analysis results confirm that the dominant failure mode in ICEB panels is bed joint sliding both pre and post peak load, with noticeable displacements at head joint locations on a few panels. Lastly, diagonal cracking along the block face was noticeable on several panels following peak load. Further testing remains to determine other factors affecting shear strength, namely, the application of normal pre-compression loads to the panel.