This thesis is a study of a home beautification project developed by the Art Club of the Travis Elementary School in Mineral Wells, Texas.

Plankhouses were functionally and symbolically integral to Northwest Coast societies, as much of economic and social life was predicated on these dwellings. This thesis investigates both plankhouse architecture and the production of these dwellings. Studying plankhouse construction and maintenance provides information regarding everyday labor, landscape use outside of villages, organization of complex tasks, and resource management. This thesis investigates three plankhouse structures at two sites, Meier and Cathlapotle, in the Lower Columbia River Region of the southern Northwest Coast of North America. Methods consisted of digitizing over 1,100 architectural features, creating detailed maps of architectural features, and conducting statistical and spatial analysis of these features. I use ethnographies, historical documents, experimental archaeology, and ecological studies to characterize the processes of plankhouse production. This information is combined with excavation data from Cathlapotle and Meier to calculate estimates of material and labor required for plankhouse-related activities. Results of this study support previous inferences regarding house architecture, construction and maintenance at the two sites. Structural elements were frequently replaced, yet overall house appearance changed little over time. Some differences in structural element use and size are noted between the two sites, suggesting that slightly different building techniques may have been employed at the two villages. Although approximate, calculations of raw materials and person days required for various building tasks provide a glimpse of the massive undertaking entailed in constructing and maintaining plankhouses. These data suggest that an enormous amount of trees were required for construction and maintenance over house occupation, approximately 700-1,200 trees at Meier, 900-2,000 trees at Cathlapotle House 1, and 150-400 trees at Cathlapotle House 4. Estimates of minimum person days entailed for tasks related to initial construction range from 1,400-2,800 at Meier, to 2,100-4,500 at Cathlapotle House 1, to 350-700 at Cathlapotle House 4. In highlighting the articulation of plankhouse labor with household reproduction, this thesis demonstrates the important interplay between material outputs, everyday action, and sociopolitical aspects of Northwest Coast society.

For three years the writer has worked with children from a section in Mineral Wells, Texas, in which home environments were unnecessarily bad. They offered none of the wholesome stimuli for growth and development that homes should give. The houses were drab and cheerless, and the grounds were neglected, often grown up in weeds or cluttered with trash. Through its members, made up of sixth and seventh grade children of Travis Elementary School and including children from the affected homes, plans and procedures were formulated for improving homes, and the interest and cooperation of the parents were secured in extending the improvements over the area. By this plan the writer hoped that life might be made more satisfying for these people as a result of improved surroundings.

Industrial effluents with high concentrations of heavy metals are widespread pollutants of great concerns as they are known to be persistent and non-degradable. Continuous monitoring and treatment of the effluents become pertinent because of their impacts on wastewater treatment plants. The aim of this study is to determine the correlation between heavy metal pollution in water and the location of industries in order to ascertain the effectiveness of the municipal waste water treatment plant. Heavy metal identification and physico-chemical analysis were done using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and multi-parameter probe respectively. Correlation coefficients of the measured values were done to investigate the effect of the industrial effluents on the treatment plants. Heavy metal resistant bacteria were identified and characterised by polymerase chain reaction and sequencing. Leeuwkuil wastewater treatment plants were effective in maintaining temperature, pH, and chemical oxygen demand within South Africa green drop and SAGG Standards whereas the purification plant was effective in maintaining the values of Cu, Zn, Al, temperature, BOD, COD, and TDS within the SANS and WHO standard for potable water. This findings indicated the need for the treatment plants to be reviewed.The industrial wastewater were identified as a point source of heavy metal pollution that influenced Leeuwkuil wastewater treatment plants and the purification plants in Vaal, Vereenining South Africa. Pseudomonas aeruginosa, Serratia marcescens, Bacillus sp. strain and Bacillus toyonensis that showed 100% similarity were found to be resistant to Al, Cu, Pb and Zn. These identified bacteria can be considered for further study in bioremediation. / Environmental Sciences / M. Sc. (Environmental Science)

Water distribution systems, electrical power transmission systems, and other civil infrastructure systems are essential to the smooth and stable operation of regional economies. Since the functions of such infrastructure systems often are inter-dependent, the systems sometimes suffer unforeseen functional disruptions. For example, the widespread power outage due to the malfunction of an electric power substation, which occurred in the northeastern United States and parts of Canada in August 2003, interrupted the supply of water to several communities, leading to inconvenience and economic losses. The sequence of such failures leading to widespread outages is referred to as a cascading failure. Assessing the vulnerability of communities to natural and man-made hazards should take the possibility of such failures into account. In seismic risk assessment, the risk to a facility or a building is generally specified by one of two basic approaches: through a probabilistic seismic hazard analysis (PSHA) and a stipulated scenario earthquake (SE). A PSHA has been widely accepted as a basis for design and evaluation of individual buildings, bridges and other facilities. However, the vulnerability assessment of distributed infrastructure facilities requires a model of spatial intensity of earthquake ground motion. Since the ground motions from a PSHA represent an aggregation of earthquakes, they cannot model the spatial variation in intensity. On the other hand, when a SE-based analysis is used, the spatial correlation of seismic intensities must be properly evaluated. This study presents a new methodology for evaluating the functionality of an infrastructure system situated in a region of moderate seismicity considering functional interactions among the systems in the network, cascading failure, and spatial correlation of ground motion. The functional interactions among facilities in the systems are modeled by fault trees, and the impact of cascading failures on serviceability of a networked system is computed by a procedure from the field of operations research known as a shortest path algorithm. The upper and lower bound solutions to spatial correlation of seismic intensities over a region are obtained.

O envelhecimento de uma instalação industrial provoca o aumento do número de falhas. A probabilidade de falhar é um indicador do momento em que deve ser feita uma parada para manutenção. É desenvolvido um método estatístico, baseado na teoria não-markoviana, para a determinação da variação da probabilidade de falhar em função do tempo de operação, que resulta num sistema de equações diferenciais parciais de natureza hiperbólica. São apresentadas as soluções por passo-fracionário e Lax-Wendroff com termo fonte. Devido à natureza suave da solução, os dois métodos chegam ao mesmo resultado com erro menor que 10−3. No caso estudado, conclui-se que o colapso do sistema depende principalmente do estado inicial da cadeia de Markov, sendo que os demais estados apresentam pouca influência na probabilidade de falha geral do sistema. / During the useful life of an industrial plant, the failure occurrence follows an exponential distribution. However, the aging process in an industrial plant generates an increase of the failure number. The failure probability is a rating for the maintenance stopping process. In this paper, an statistical method for the assessment of the failure probability as a function of the operational time, based on the non-Markovian theory, is presented. Two maintenance conditions are addressed: In the first one, the old parts are utilized, after the repair this condition being called as good as old; in the second one the old parts are substituted by brand new ones this condition being called as good as new. A non-Markovian system with variable source term is modeled by using hyperbolic partial differential equations. The system of equations is solved using the Lax-Wendroff and fractional-step numerical schemes. The two methods achieve to approximately the same results, due to the smooth behavior of the solution. The main conclusion is that the system collapse depends essentially on the initial state of the Markov chain.

O envelhecimento de uma instalação industrial provoca o aumento do número de falhas. A probabilidade de falhar é um indicador do momento em que deve ser feita uma parada para manutenção. É desenvolvido um método estatístico, baseado na teoria não-markoviana, para a determinação da variação da probabilidade de falhar em função do tempo de operação, que resulta num sistema de equações diferenciais parciais de natureza hiperbólica. São apresentadas as soluções por passo-fracionário e Lax-Wendroff com termo fonte. Devido à natureza suave da solução, os dois métodos chegam ao mesmo resultado com erro menor que 10−3. No caso estudado, conclui-se que o colapso do sistema depende principalmente do estado inicial da cadeia de Markov, sendo que os demais estados apresentam pouca influência na probabilidade de falha geral do sistema. / During the useful life of an industrial plant, the failure occurrence follows an exponential distribution. However, the aging process in an industrial plant generates an increase of the failure number. The failure probability is a rating for the maintenance stopping process. In this paper, an statistical method for the assessment of the failure probability as a function of the operational time, based on the non-Markovian theory, is presented. Two maintenance conditions are addressed: In the first one, the old parts are utilized, after the repair this condition being called as good as old; in the second one the old parts are substituted by brand new ones this condition being called as good as new. A non-Markovian system with variable source term is modeled by using hyperbolic partial differential equations. The system of equations is solved using the Lax-Wendroff and fractional-step numerical schemes. The two methods achieve to approximately the same results, due to the smooth behavior of the solution. The main conclusion is that the system collapse depends essentially on the initial state of the Markov chain.

Les travaux présentés dans ce manuscrit visent à développer des modèles de coût/performances pour améliorer les décisions de maintenance sur les infrastructures ferroviaires exploitées dans un environnement de plus en plus contraint: trafic accru, détérioration accélérée, temps de maintenance réduits. Les modèles de maintenance proposés sont construits à base de réseaux de Petri colorés ; ils sont animés par simulation de Monte Carlo pour estimer les performances (en termes de coût et de disponibilité) des politiques de maintenance considérées. Ils sont développés aux niveaux "composant" et "réseau", et plusieurs problèmes de maintenance différents sont étudiés. Au niveau "composant" (rail), des politiques de maintenance mettant en jeu différents niveaux d'information de surveillance sont comparées pour montrer l'intérêt de surveiller la détérioration graduelle du composant. L'effet de l'existence d'un délai de maintenance est également étudié pour les politiques conditionnelle et périodique. Au niveau système (ligne), une maintenance mettant en jeu différents types d'inspections complémentaires (automatique ou visuelle) est d'abord étudiée. On s'intéresse ensuite au cas de figure où l'évolution de la détérioration dépend du mode d'utilisation et de la charge de la voie : le problème de maintenance étudié vise alors à définir un réglage optimal des paramètres d'exploitation de la voie (vitesse limite) et de maintenance (délai d'intervention) / The aim of this thesis research work is to propose maintenance models for railways infrastructures that can help to make better maintenance decisions in the more constrained environment that the railway industry has to face, e.g. increased traffic loads, faster deterioration, longer maintenance planning procedures, shorter maintenance times. The proposed maintenance models are built using Coloured Petri nets; they are animated through Monte Carlo simulations to estimate the performance of the considered maintenance policies in terms of cost and availability. The maintenance models are developed both at the component and network levels, and several different maintenance problems are considered. At the rail component level, maintenance policies with different level of monitoring information (level of gradual deterioration vs binary working state) are compared to show the benefits of gathering monitoring information on the deterioration level. The effect of preventive maintenance delays is also investigated for both condition-based inspection policies and periodic inspection policies on a gradually deteriorating component. At the line level, a maintenance policy based on a two-level inspection procedure is first investigated. Then, considering the case when the deterioration process depends on the operation modes (normal vs limited speed), a maintenance optimization problem is solved to determine an optimal tuning of the repair delay and speed restriction