Thesis (doctoral)--Université de Paris, 1921. / Includes bibliographical references (p. [131]-136) and index.

This creative nonfiction dissertation is a series of braided narratives that chronicle the author's career as a trombonist in the John Smith Ensemble. As an amateur trombonist, the author is shocked to be hired as a professional musician for an orchestra that plays on PBS and at Carnegie Hall. She quickly realizes, however, that the job requires her to play the trombone quietly in front of an unplugged microphone while a CD recording of another, more talented trombonist is blasted out toward an unknowing audience. The job also requires the author to tour around America. The scenes of from this tour are braided with scenes wherein she reflects on her life as a professional fake musician and her past failed attempts at getting a job.

Bearings are critical in today’s mechanisms, and their reliability is continuously improving. Yet, working under high loads for long periods, bearings will degrade and eventually fail. An unpredicted bearing failure can lead to total and catastrophic failures of machines and may even lead to human injuries that result in substantial economic losses and reductions in production. Determining a bearing’s remaining useful life (RUL) has become an important topic in many industrial fields. Vibration signals are the most used representation for understanding a bearing’s health status. Using different algorithms, time-domain vibration signals can be transformed into time-frequency domain signals that help indicate a bearing’s status. For instance, this thesis investigates spectrograms and scalograms to visually represent a bearing’s health condition using a short-time Fourier transform (STFT) and a continuous wavelet transform (CWT). Both representations are plotted as a function of time and frequency and can detect the bearing’s working condition. However, spectrograms are advantageous in revealing frequency changes along the time axis, while scalograms facilitate the detection of abrupt changes. Combined with a convolutional neural network (CNN), these plots can be used to interpret bearing RUL. The strength of CNNs lie in their ability to identify and detect features in images, including such tasks as image classification, using share-weight architectures, convolutional layers, and kernels. This thesis explores CNNs combined with spectrograms and scalograms using the PRONOSTIA dataset to perform bearing RUL predictions and explore relationships between prognosis and diagnosis for bearing faults analysis.

No description available.

Since prehistoric times medicinal plants have been an invaluable source of medicinal preparations to mankind due to their respective chemical constituents. The family of the Mesembryanthemaceae is almost entirely endemic to southern Africa, and the subfamily Mesembryanthemoideae is a key source of previous reports of plants with traditional uses, both medicinal and culinary. In this thesis, phytochemical investigations were performed on a representative sample of the Mesembryanthemaceae genera and species, with emphasis on the subfamily Mesembryanthemoideae. The aims of this study were to record all ethnobotanical information on the medicinal and culinary uses of the Mesembryanthemaceae, and to isolate and identify alkaloids from selected taxa (especially those of medicinal interest) with specific emphasis on mesembrane alkaloids A review on the structural classification, biosynthesis and biological properties of the mesembrane alkaloids is presented in this dissertation. Experimentally, extracts of the 67 plants encompassing 15 genera and approximately 26 species which were investigated were prepared using one of two alkaloid extraction procedures, following which the extracts were screened for the presence of alkaloids by thin-layer chromatography. The extracts in which alkaloids were detected were analysed further using gas chromatography/mass spectrometry. Where possible, pure alkaloids were isolated from the crude alkaloid extracts and the pure compounds characterised using 1H and 13C nuclear magnetic resonance spectroscopy. Six of the mesembrane alkaloids as well as the tyrosine-derived non-mesembrane alkaloid hordenine were found to be distributed amongst the various genera and species of the Mesembryanthemoideae. The mesembrane alkaloids detected include mesembrine, mesembrenone, mesembrenol, mesembranol, 4’-Omethylsceletenone and 4,5-dihydro-4’-O-methylsceletenone. Within the genus Sceletium mesembrine, mesembrenone, mesembrenol, mesembranol and hordenine were identified. Mesembrine, mesembrenone, mesembranol and hordenine were also detected in Aridaria. The sceletenone derivatives 4’-Omethylsceletenone and 4,5-dihydro-4’-O-methylsceletenone as well as hordenine were identified as the major alkaloid constituents of the genus Aptenia. No alkaloids were detected in the species of Brownanthus and Prenia investigated in this study. Amongst the genera Mesembryanthemum, Phyllobolus and Psilocaulon, a random distribution of the alkaloid hordenine was observed. During the course of this study, the isolation and characterisation of 4’-O-methylsceletenone and 4,5-dihydro-4’-O-methylsceletenone from both Aptenia cordifolia and Aptenia lancifolia, as well as the non-mesembrane alkaloid hordenine from a number of species, was achieved. The two mesembrane alkaloids have been prepared synthetically, but this is the first report of the presence of the compounds in a natural source. / Prof. F.R. van Heerden

In the oil and gas industry, statistical methods have been used for corrosion analysis for various asset systems such as pipelines, storage tanks, and so on. However, few industrial standards and guidelines provide comprehensive stepwise procedures for the usage of statistical approaches for corrosion analysis. For example, the UK HSE (2002) report "Guidelines for the use of statistics for analysis of sample inspection of corrosion" demonstrates how statistical methods can be used to evaluate corrosion samples, but the methods explained in the document are very basic and do not consider risk factors such as pressure, temperature, design, external factors and other factors for the analyses. Furthermore, often the industrial practice that uses linear approximation on localised corrosion such as pitting is considered inappropriate as pitting growth is not uniform. The aim of this research is to develop an approach that models the stochastic behaviour of localised corrosion and demonstrate how the influencing factors can be linked to the corrosion analyses, for predicting the remaining useful life of components in oil and gas plants. This research addresses a challenge in industry practice. Non-destructive testing (NDT) and inspection techniques have improved in recent years making more and more data available to asset operators. However, this means that these data need to be processed to extract meaningful information. Increasing computer power has enabled the use of statistics for such data processing. Statistical software such as R and OpenBUGS is available to users to explore new and pragmatic statistical methods (e.g. regression models and stochastic models) and fully use the available data in the field. In this thesis, we carry out extreme value analysis to determine maximum defect depth of an offshore conductor pipe and simulate the defect depth using geometric Brownian motion in Chapter 2. In Chapter 3, we introduce a Weibull density regression that is based on a gamma transformation proportional hazards model to analyse the corrosion data of piping deadlegs. The density regression model takes multiple influencing factors into account; this model can be used to extrapolate the corrosion density of inaccessible deadlegs with data available from other piping systems. In Chapter 4, we demonstrate how the corrosion prediction models in Chapters 2 and 3 could be used to predict the remaining useful life of these components. Chapter 1 sets the background to the techniques used, and Chapter 5 presents concluding remarks based on the application of the techniques.

Thesis (PhD. (Anthropology)) --University of Limpopo, 2008 / In this study, the multidisciplinary epistemology of ethnobotany is reviewed within the wider context of ethnoecology and indigenous knowledge systems. The major problems derived from this theoretical framework cover aspects of the relationship between cultural groups and their natural environment - particularly the botanical component of the latter. Problems and critical questions about this relationship were investigated in selected areas of the Bushbuckridge district, which are inhabited by a number ofTsonga-Shangana communities. Salient aspects of the natural habitat in the study area are discussed with special reference to the vegetation, climate and soil types. A proper understanding of the culturally-based exploitation of plant resources necessitates a sound knowledge of the culture concerned, including relevan t aspects of its value-system and cosmology. In this review, emphasis is placed on those aspects of culture that are directly concerned with the utilisation of plant resources. The latter include a wide range of economic, technological and medicinal uses. Specimens of 200 plants were collected and identified by the University of Limpopo Herbarium. The uses of every species are described. Systematised tables of plant uses are presented, as well as comparative lists in which selected uses are compared to those of other cultures in which the same species are used. The effects of plant utilisation, as well as indigenous forms of resource management, are also discussed. Recommendations are made on how to counter the process of environmental degradation which is caused by over-exploitation .

Orientador: Ariene Gimenes Fernandes Van Dender / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T22:25:48Z (GMT). No. of bitstreams: 1 Alves_RosaMariaVercelino_D.pdf: 5293051 bytes, checksum: 173b3b436555b3d5de8b3a01b60feee3 (MD5) Previous issue date: 2004 / Resumo: Requeijão cremoso é um produto genuinamente brasileiro, sendo classificado como um tipo de queijo processado obtido pelo cozimento de uma massa de queijo fresco de sais fundentes, água e creme de leite. Atualmente esse produto é acondicionado principalmente em copos de vidro com sistema de fechamento metálico de fácil abertura, ficando durante sua comercialização, exposto a luz em gôndolas dos refrigeração. Pelo fato de não serem encontrados dados em literatura sovre principais fatores que interferem em sua vida util, a introdução de novas alternativas para este segmento acaba sendo limitada. Assim, o objetivo desse trabalho foi estudar o efeito da disponibilidade de oxigênio e de incidência de luz sobre a estabilidade do requeijão cremoso através da ánálise comparativa da sua estabilidade quando acondicionado em diferentes tipos de embalagem, na ausência e presença de luz, determinando os efeitos das caracteristicas de barreira ao oxigênio, à umidade e à luz da embalagem e da quantidade de oxigênio disponivel no espaço-livre nas caracteristicas microbiológicas, fisico-quimicas e sensoriais do produto, ao longo da estocagem refrigerada. O produto foi produzido na planta piloto do TECNOLAT/ITAL a partir de uma massa obtida por acidificação direta de leite aquecido a 80°C. O produto foi acondicionado em cinco diferentes tipos de embalagens (copo de vidro com tampa metálica abre-fácil, copo de vidro termosselado, pode plástico de polipropileno termosselado, bisnagas plásticas coextrudadas e de polietileno). De maneira geral, não foram observadas alterações microbiologicas no requeijão cremoso acondicionado nos cinco tipos de embalagens indicando condições adequadas de processo e fechamento das embalagens em estudo. Também não se observaram alterações fisico-quimicas do produto, pois as variações observadas encontravam-se dentro dos padrões normais para requeijão cremoso. Quanto ao indice de proteólise, este indicou estabilidade do sistema protéico do produto em todas as em balagens até 150 doas de estocagem e até 180 dias no copo de vidro com tampa metálica abre fácil. Os resultados de TBA, quando indicavam diferenças entre as amostras provinientes das diferentes embalagens expostas ou não à luz, oxidação do produto era muito acentuada e o mesmo já havia sidp rejeitado na análise sensorial. Em ausência de luz, a disponibilidade de oxigênio, seja presente no espaço-livre, seja por permeação pela embalagem, não afeta a perda de qualidade do requeijão cremoso para periodos de estocagem de até 150 dias a 10°C e 180 dias a 4°C. Também verificou-se que em ausência de luz, o efeito das temperaturas de estocagem estudadas, 10°C e 4°C foi pouco significativo. Entretanto, a perda de qualidade de requeijão cremoso é significamente maior se a estocagem do produto acondicionado nas embalagens for sob exposiçãoà luz, quando observou-se alteração na fase lipidica levando à alteração sensorial do produto com requeijão e definição de final de vida útil. Sob exposição à luz, o efeito de uma alta taxa de transmissão ao oxigênio foi observado, uma vez que a estabilidade do produto foi menor quando acondicionado na bisnaga PE em compração com a obtida na estrutura da bisnaga Coex. Também verificou-se que o volume de oxigênio disponivel afeta a estabilidade do produto de forma que, a partir de uma determinada concentração de oxigênio, seja por volume de gases no espaço-livre, ou seja por permeação, as reações de fotoxidação são muito aceleradas, uma vez que não foi observada diferença significativa no produto do vidro selado (VS), no pote de polipropilrno (pote PP) e na bisnaga Coes (EVOH como camada barreira ao oxigênio). E, sob exposição à luz, em condições de menor volume de oxigênio disponivel no espaço-livre da embalagem, a redução da pressão parcial de oxigênio no espaço-livre permite um éríodo de vida útil maior para o produto, porque menor é a disponibilidade de oxigênio no produto para ser consumido nas reações fotoxidativas (situação do VAF). Entre as embalagens estudadas, o vidro com sistema de fechamento por vácuo (VAF) foi o que preservou por mais tempo a qualidade inicial do produto, uma vez que apresenta a situação de minima disponibilidade de oxigênio. recomenda-se que caso se opte pela utilização de embalagens plásticas, que seja dada preferência para as com pigmentação do material, que garanta proteção contra a incidência de luz, aumentado assim a estabilidade do produto / Abstract: Creamy Requeijão is a genuinamente Brazilian product, being classified as a type of processed cheese gotten by the baking of a mass of cool cheese of you leave fundentes, water and cream of milk. Currently this product is conditioned mainly in glass cups with system of metallic closing of easy opening, being during its commercialization, displayed the light in gondolas of the refrigeration. For the fact not to be joined data in literature sovre main factors that intervene with its util life, the introduction of new alternatives for this segment finishes being limited. Thus, the objective of this work was to study the effect of the availability of oxygen and incidence of light on the stability of the creamy requeijão through ánálise comparative of its stability when conditioned in different types of packing, in the absence and presence of light, determining the effect of the caracteristicas of barrier to the oxygen, the humidity and the light of the packing and the amount of oxygen disponivel in the space-free one in the microbiological, fisico-quimicas and sensorial caracteristicas of the product, the long one of the cooled stockage. The product was produced in the plant pilot of the TECNOLAT/ITAL from a mass gotten for direct acidificação of warm milk 80°C. The product was conditioned in five different types of packings (glass cup with open-easy metallic cover, termosselado glass cup, can plastic of termosselado polypropylene, coextrudadas plastic longs loaf of french bread and of polyethylene). In general way, microbiologicas alterations in the creamy requeijão conditioned in the five types of packings had not been observed indicating adequate conditions of process and closing of the packings in study. Also fisico-quimicas alterations of the product had not been observed, therefore the observed variations met inside of the normal standards for creamy requeijão. How much to the indice of proteólise, this indicated stability of the protéico system of the product in all in balagens up to 150 donates of stockage and up to 180 days in the glass cup with metallic cover it opens easy. The TBA results, when they indicated differences between the provinientes samples of the different packings displayed or not to the light, oxidation of the product was very accented and the same already it had sidp rejected in the sensorial analysis. In light absence, the availability of oxygen, either present in the space-free one, either for permeação for the packing, does not affect the loss of quality of the creamy requeijão for periodos of stockage of up to 150 days 10°C and 180 days 4°C. Also it was verified that in light absence, the effect of the studied temperatures of stockage, 10°C and 4°C were little significant. However, the loss of quality of creamy requeijão is significamente bigger if the stockage of the product conditioned in the packings will be under exposiçãoà light, when alteration in the lipidica phase was observed taking to the sensorial alteration of the product with requeijão and definition of end of useful life. Under exposition to the light, the effect of one high tax of transmission to the oxygen was observed, a time that the stability of the product lesser when was conditioned in long loaf of french bread PE in compração with the gotten one in the structure of the Coex long loaf of french bread. Also it was verified that the volume of oxygen disponivel affects the stability of the form product that, from one determined oxygen concentration, either for volume of gases in the space-free one, or either for permeação, the fotoxidação reactions very are sped up, a time that were not observed significant difference in the product of the stamped glass (VERSUS), in the pot of polipropilrno (pot PP) and in the Coes long loaf of french bread (EVOH as layer barrier to the oxygen). E, under exposition to the light, in conditions of lesser volume of oxygen disponivel in the space-free one of the packing, the reduction of the partial pressure of oxygen in the space-free one allows one éríodo of bigger useful life for the product, because lesser it is the availability of oxygen in the product to be consumed in the fotoxidativas reactions (situation of the VAF). Between the studied packings, the glass with system of closing for vacuum (VAF) was what it preserved for more time the initial quality of the product, a time that presents the situation of minima oxygen availability sends regards that in case that if opts to the use of plastic packings, that is given preference for the ones with pigmentação of the material, that guarantees protection against the light incidence, increased thus the stability of the product / Doutorado / Doutora em Tecnologia de Alimentos

Yes / Diagnostics and prognostics have significant roles in the reliability enhancement of systems and are focused topics of active research. Engineered systems are becoming more complex and are subjected to miscellaneous failure modes that impact adversely their performability. This everincreasing complexity makes fault diagnostics and prognostics challenging for the system-level functions. A significant number of successes have been achieved and acknowledged in some review papers; however, these reviews rarely focused on the application of complex engineered systems nor provided a systematic review of diverse techniques and approaches to address the related challenges. To bridge the gap, this paper firstly presents a review to systematically cover the general concepts and recent development of various diagnostics and prognostics approaches, along with their strengths and shortcomings for the application of diverse engineered systems. Afterward, given the characteristics of complex systems, the applicability of different techniques and methods that are capable to address the features of complex systems are reviewed and discussed, and some of the recent achievements in the literature are introduced. Finally, the unaddressed challenges are discussed by taking into account the characteristics of automotive systems as an example of complex systems. In addition, future development and potential research trends are offered to address those challenges. Consequently, this review provides a systematic view of the state of the art and case studies with a reference value for scholars and practitioners.

Much about visual spatial attention has been learned from studying how observers respond to two-dimensional stimuli. Less is known about how attention varies along the depth axis. Most of the work on the effect of depth on spatial attention manipulated binocular disparity defined depth, and it is less clear how monocular depth cues affect spatial attention. This thesis investigates the effect of target distance on peripheral detection in a virtual three-dimensional environment that simulated distance using pictorial and motion cues. Participants followed a lead car at a constant distance actively or passively, while travelling along a straight trajectory. The horizontal distribution of attention was measured using a peripheral target detection task. Both car-following and peripheral detection were tested alone under focussed attention, and simultaneously under divided attention. Chapter 2 evaluated the effect of target distance and eccentricity on peripheral detection. Experiment 1 found an overall near advantage that increased at larger eccentricities. Experiment 2 examined the effect of anticipation on target detection and found that equating anticipation across distances drastically reduced the effect of distance in reaction time, but did not affect accuracy. Experiments 3 and 4 examined the relative contributions of pictorial cues on the effect of target distance and found that the background texture that surrounded the targets could explain the main effect of distance but could not fully account for the interaction between distance and eccentricity. Chapter 3 extended the findings of Chapter 2 and found that the effect of distance on peripheral detection in our conditions was non-monotonic and did not depend on fixation distance. Across chapters, dividing attention between the central car-following and peripheral target detection tasks consistently resulted in costs for car-following, but not for peripheral detection. This work has implications for understanding spatial attention and design of advanced driver assistance systems. / Dissertation / Doctor of Science (PhD) / Our visual world is complex and dynamic, and spatial attention enables us to focus on certain relevant locations of our world. However, much of what we know about spatial attention has been studied in the context of a two-dimensional plane, and less is known about how it varies in the third dimension: depth. This thesis aims to better understand how spatial attention is affected by depth in a virtual three-dimensional environment, particularly in a driving context. Generally, driving was simulated using a car-following task, spatial attention was measured in a task that required detecting targets appearing at different depths indicated by cues perceivable with one eye. The results of this work add to the literature that suggests that spatial attention is affected by depth and contributes to our understanding of how attention may be allocated in space. Additionally, this thesis may have implications for the design of in-car warning systems.