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This thesis presents a method for optimizing cable configuration inside a large magnetic cylindrical steel casing, from the total ampacity point of view. The method is comprised of two main parts, namely: 1) analytically calculating the electromagnetic losses in the steel casing and sheathed cables, for an arbitrary cables configuration, and 2) implementing an algorithm for determining the optimal cables configuration to obtain the best total ampacity. The first part involves approximating the eddy current and hysteresis losses in the casing and cables. The calculation is based on the theory of images, which this thesis expands to apply to casings having both high magnetic permeability and high electric conductivity at the same time. The method of images, in combination with approximating the cable conductors and sheaths as multiple physical filaments, is used to compute the final current distributions in the cables and pipe and thus the associated losses. The accuracy of this computation is assessed against numerical solutions obtained using the Maxwell finite element program by Ansoft. Next, the optimal cable configuration is determined by applying a proposed two-level optimization algorithm. At the outer level, a combinatorial optimization based on a genetic algorithm explores the different possible configurations. The performance of every configuration is evaluated according to its total ampacity, which is calculated using a convex optimization algorithm. The convex optimization algorithm, which forms the inner level of the overall optimization procedure, is based on the barrier method. This proposed optimization procedure is tested for a duct bank installation containing twelve cables and fifteen ducts, comprising two circuits and two cables per phase, and compared with a brute force method of considering all possible configurations. The optimization process is also applied to an installation consisting of a single circuit inside a large magnetic steel casing.

The MIRI-MRS is a future space based Medium Resolution Spectrometer and one of four instruments to be integrated onto The James Webb Space Telescope. The Medium Resolution Spectrometer is designed to be diffraction limited across its entire passband of 5 - 28.3 microns. It achieves this through the spectral filtering of the passband into four channels with each one containing an integral field unit optimised for minimal diffraction losses. The integral field unit enables the simultaneous measurement of the spectral data across the entire field of view. The design of the Medium Resolution Spectrometer is outlined with particular reference to the choice of slice widths used for each channel to minimise the diffraction losses from the slicing mechanism. The slice widths are also used to derive the extent of the field of view and combined with the along slice plate scale at the detector the technique required for complete spatial sampling of the spectrometer is outlined. The operation of the Channel 1 image slicer component was tested cryogenically at 5 microns for diffraction losses due to the slicing of the point spread function. This was so that the actual diffraction losses could be measured and compared with the optical model. From the resulting analysis I concluded that the operation of the image slicers were well understood for diffraction losses. Performance tests were required on the instrument because of its novel design. This was the first implementation of an integral field unit operating between 5 - 28.3 microns and it was necessary to ensure that the operation of the image slicer did not induce unacceptable diffraction losses into the instrument. Tests were required on the assembled instrument to verify the optical design. A Verification Model of MIRI was built to enable test verification of the optical design. This testing was carried out in advance of the MIRI Flight Model assembly so that changes could be made to the Flight Model design if necessary. This testing phase was also designed to define the calibration process necessary to prepare the MIRI Flight Model for scientific operations. For the testing phase it was necessary to create an astronomical source simulator. This MIRI Telescope Simulator was constructed in Madrid where I spent two months ensuring the point source movement across the field of view would be sufficient to investigate the Medium Resolution Spectrometer. My contribution was to help assemble both the Verification and Flight Models. I also participated in the Verification Model testing phase from the test design phase to the test implementation and data analysis. My role in the analysis was to investigate the field of view of the Medium Resolution Spectrometer Verification Model and whether the field of view requirements for the spectrometer were met. During this analysis I also verified that the diffraction effects of the end-to-end instrument were well understood by the optical model. The Medium Resolution Spectrometer Verification Model field of view compromised the field of view requirement for the spectrometer. A similar analysis for the Flight Model showed that there would be a low probability that the field of view requirement would be met. As a result of the analysis I defined a new slit mask design that would align the field of view sampled by Channel 1 to increase the aligned field of view. As a result there is a high probability that the field of view requirement for the Flight Model will be exceeded. The test analysis discovered a magnification effect within the spectrometer which must be properly characterised to enable accurate field of view reconstruction. I designed a test necessary for the calibration phase of the Flight Model to enable full spatial alignment of the Medium Resolution Spectrometer. I also measured an excess flux level in the Channel 1 observations at the detector and there was a ghost detected in the Channel 1 images. Whilst the origin of either the excess flux or the ghost could not be completely determined I investigated the possibility that they will not be present in the Flight Model due to the slight design differences. If present however they will not increase the background level of an observation above the requirement outlined for Channel 1.

The thermal regime of a gearbox is of considerable importance to its performance. Several significant gearbox parameters, such as the efficiency and fatigue life of its components, are temperature dependent. It is thus important to be able to determine the temperatures of the gearbox components during operation, but they are difficult to measure experimentally. A simulation model capable of predicting these temperatures would therefore be a valuable tool. The objective of this master’s thesis was to create a model capable of simulating the thermal regime of a truck gearbox during operation. To do this, mechanical losses in the gearbox, heat exchange with the surroundings, as well as heat transfer between components had to be accounted for. The model was created using the 1D simulation software LMS Imagine.Lab Amesim 14.0, and is based on a combination of mechanical and thermal networks. Details of the mechanical and thermal interactions between components are calculated using empirical and analytical formulas for mechanical losses and heat transfer. The result of the thesis is a model which can be used to simulate either real or idealised load cases, from which temperatures of gear wheels, shafts, bearings, housing and gearbox oil may be studied, as well as gearbox losses and heat transfer. Comparisons between simulated and measured gearbox efficiencies show good correlation. It is also shown that the model can predict oil temperatures which agree with in-vehicle measurements. Due to a lack of measurement data, most simulated component temperatures cannot be compared to measured values. However, temperature measurements performed for one of the gear wheels indicate that the model can be used to predict their temperature. In order to demonstrate the capabilities of the model, example results from both real and idealised load cases are presented.

The primary objective of this dissertation was to identify and estimate the relative importance of factors used by the Tax Court in deciding hobby loss cases. This was accomplished in two steps. The first step was to review the Treasury Regulations, cases and literature pertaining to hobby losses to determine the relevant factors used by the Court in deciding this issue. The second step involved using probit analysis to identify which of these factors actually influenced the Court in deciding hobby loss cases and to determine the relative importance of the factors. A secondary purpose was to to explore the probit model's ability to predict decisions likely to be appealed. The probit model was based on the analysis of 219 post-1954 Tax Court cases involving determination of whether activities were or were not engaged in for profit. By application of log-likelihood techniques, it was determined that the model developed was stable over time and across lines of "business," the implication being that cases decided both before and after the passage of Section 183 and involving all types of activity should have precedential value in conflicts between taxpayers and the Internal Revenue Service. Five factors were found to be significant predictors: manner of operation, level of expertise, time expended, history of income and loss, and presence of elements of personal pleasure. It is important to note that the two factors not susceptible to tax planning--success in other activities and financial status of the taxpayer--were insignificant discriminators between business and hobby outcomes. The implication is that with careful tax planning, one can organize and operate a given activity so that it is likely to receive favorable tax treatment. The probit model proved to be unable to predict decisions likely to be appealed. The probability that a particular case would be classified by the Court as a business did not appear to be a significant predictor of whether a taxpayer would appeal an adverse decision.

Hydraulic losses in sewer pipes are caused by wall roughness, blockages and in-pipe sedimentation. Hydraulic resistance is a key parameter that is used to account for the hydraulic energy losses and predict the sewer system propensity to flood. Unfortunately, there are no objective methods to measure the hydraulic resistance in live sewers. A common method to estimate the hydraulic resistance of a sewer is to analyse collected CCTV images and then to compare them against a number of suggested hydraulic roughness values published in the Sewer Rehabilitation Manual. This thesis reports on the development of a novel, non-invasive acoustic method and instrumentation to measure the hydraulic roughness in partially filled pipes under various structural and operational conditions objectively. This research presents systematic laboratory and field studies of the hydraulic and surface water wave characteristics, of shallow water flows in a sewer pipes with the presence of local and distributed roughness, in order to relate them to some fundamental properties of the acoustic field measured in the vicinity of the flow surface. The results of this thesis indicate that for the local roughness the energy content of the reflected acoustic signal is an indicator of the pipe head loss and hydraulic roughness. In the case of the distributed roughness, the variation in the temporal and frequency characteristics of the propagated sound wave can be related empirically to the mean flow depth, mean velocity, wave standard deviation and hydraulic roughness.

Master of Science / Department of Psychological Sciences / Kimberly Kirkpatrick / The present experiments examined the effect of different uncertain-reward magnitudes (i.e., gains and losses) on global and local probabilistic choice behavior in rats. In two experiments, rats were given a choice between a variable-amount certain outcome that delivered 2 or 4 pellets and a variable-amount uncertain outcome that probabilistically delivered a larger reward. In Experiment 1, the larger uncertain outcome was always 11 pellets and different groups received 1, 2, or 4 pellets for the uncertain small reward. In Experiment 2, the uncertain small reward was always 4 pellets and different groups received 6, 9, or 11 pellets for the uncertain large reward. In both experiments, the rats increased their uncertain choice behavior with the probability of uncertain food. In Experiment 1, the magnitude of the uncertain small outcome affected choice behavior; there was no such effect of the uncertain large reward magnitude in Experiment 2. The group differences in choice behavior suggest that the expected value of the certain choice served as a reference point distinguishing uncertain gains and losses, and that the rats exhibited differential sensitivities to such outcomes. As some extant theoretical frameworks of choice behavior seem unable to account for all of the present data, a possible mechanism for the present results is proposed. These results emphasize the importance of identifying the choice outcomes that constitute gains and losses in animals such that the effects of prior uncertain gains and losses on subsequent choice behavior can be adequately and comprehensively understood.

Call number: LD2668 .T4 1986 N48 / Master of Science / Animal Science and Industry

[pt] Atualmente, um dos maiores problemas das empresas brasileiras distribuidoras de energia elétrica é o de perdas comerciais, responsáveis pela maior parte das perdas do setor. A Light, por exemplo, é a terceira distribuidora com maiores perdas comerciais no Brasil, com 3,79 milhões de clientes de baixa tensão em 31 municí­pios do Estado do Rio de Janeiro. Estas perdas são causadas por fraudes nos medidores de energia, por equipamentos defeituosos e, principalmente, pelas ligações clandestinas, conhecidas por gatos, gambiarras ou macacos. Uma forma tradicional de combate às Perdas Comerciais é a realização de inspeções nos consumidores. Entretanto, a seleção de quais consumidores devem ser inspecionados é uma tarefa árdua para os especialistas no assunto. As distribuidoras geralmente empregam um conjunto de metodologias heurí­sticas para identificar os clientes de baixa tensão suspeitos de estarem cometendo algum tipo de irregularidade. Todavia, a média de acertos dessas metodologias ainda é bastante inferior ao desejado, acarretando prejuízos elevados para as distribuidoras brasileiras. No caso especí­fico da Light, a média de acerto na comprovação de clientes fraudadores é de apenas 25%. Verifica-se, portanto, que o processo adotado não é eficiente. Portanto, este trabalho tem como objetivo desenvolver uma metodologia que identifique, com maior precisão, o perfil do cliente irregular (comprovada fraude no medidor, furto por ligação clandestina ou irregularidade técnica). O sistema inteligente resultante, denominado SIIPERCOM, baseia-se em Redes Neurais, para a filtragem agrupando clientes com comportamentos semelhantes e classificação dos clientes de cada grupo em normais ou irregulares. / [en] Currently, one of the biggest problems of Brazilian companies distributing electrical power is the loss commercial, responsible for most of the losses in the sector. The Light, for example, is the third largest distributor with commercial losses in Brazil, with 3.79 million clients of low voltage in 31 municipalities in the State of Rio de Janeiro. These losses are caused by fraud in the energy meters, for defective equipment, and principally by illegal connections, known as cats, stage lights or monkeys. The traditional form to combat to the commercial losses is the realization of inspections on consumers. However, the selection of which consumers should be inspected is an arduous task to specialists in the subject. The distributors usually employ a range of methodologies heuristics to identify customers with low voltage suspected to be committing some type of irregularity. However, the average of correct these methodologies is still much lower than desired, causing heavy losses to Brazilian distributors. In the specific case of Light, the average hit the evidence of customers fraudsters is only 25%. It appears therefore that the process adopted is not efficient. Therefore, this study aims to develop a methodology to identify, with greater precision, the irregular profile of the customer (meter was proven fraud, theft by illegal connection or technical irregularity). The resulting intelligent system, called SIIPERCOM, based on Neural Networks, for the 'filtering' grouping customers with similar behaviors and classification of the customers of each group in normal or irregular.

Thesis (M.Com. (Taxation))--University of the Witwatersrand, Faculty of Commerce, Law and Management, School of Accountancy , 2015. / Could not copy abstract