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O dimensionamento seguro e econômico de dissipadores de energia por ressalto hidráulico formado a jusante de vertedouros passa pela compreensão de como se processa a dinâmica do escoamento. Para que isso seja possível é necessário que sejam identificadas as características macroturbulentas do escoamento, tanto no que diz respeito aos valores médios quanto às parcelas flutuantes e extremas dos esforços de pressões atuantes junto ao fundo. Este trabalho, então, propõe a análise dos esforços hidrodinâmicos atuantes na estrutura hidráulica a partir de uma nova abordagem que preconiza que os esforços atuantes junto ao fundo devem ser avaliados como um somatório dos efeitos hidrodinâmicos ocasionados pelas distintas condições do escoamento. Dessa forma, foram avaliados individualmente os efeitos: (i) da curva de concordância vertical entre o perfil vertente e a bacia de dissipação e a sua influência sobre esta, (ii) do escoamento em regime rápido sobre um plano horizontal, (iii) da macroturbulência presente no ressalto hidráulico livre (tipo A) e (iv) do afogamento do ressalto hidráulico. Essa avaliação individualizada proporciona, em última instância, a identificação global dos esforços atuantes junto à estrutura hidráulica, conferindo sensibilidade a esta análise global a partir da identificação da influência de cada um dos efeitos atuantes e das respectivas consequências sobre a bacia de dissipação. O trabalho apresenta, assim, um método analítico de previsão de pressões médias, flutuantes e extremas atuantes ao longo de uma bacia de dissipação por ressalto hidráulico, quer este seja formado integralmente na bacia de dissipação, quer este seja formado parcialmente sobre o perfil vertente, condição predominante na operação de sistemas estruturais de dissipação de energia hidráulica. / To safely and economically design hydraulic jump energy dissipators downstream spillways the comprehension of the flow dynamics is needed. To achieve this it is needed to identify the macroturbulent characteristics of the flow, both the mean pressure values as well as the fluctuating and extreme pressures acting on the floor of the stilling basin. The present work proposes to analyze the hydrodynamic forces acting on the structures by means of a new approach which states that the pressures acting on the basin floor can be evaluates as the sum of hydrodynamic effects caused by the distinct flow conditions. The following effects were individually evaluated (i) transition from the spillway slope to the flat basin slope. (ii) supercrítical flow over a flat slope, (iii) macroturbulence present in a classic hydraulic jump (type A jump) and (iv) jump submergence. This individualized evaluation aims to identify the global forces acting on the spillway structure conferring sensitivity to the global analysis from the identification of each of the acting effects and its consequences. The present work relates an analytical method for predicting of mean, fluctuating and extreme pressures acting on a hydraulic jump stilling basin, be it formed integrally on the structure or partially over the spillway, usual condition in the basin operation.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The survival of organisms in heterogeneous and instable environment requires sometimes physiologic and morphologic adjustment, thus involving complex regulator mechanisms. On the other hand, the organisms themselves also have a kind of ability to resist either genetic disturbs or environmental troubles while in development, producing a phenotype pre determined. The main purpose of this study is to verify whether there have been differences in the size and levels of fluctuating asymmetry (FA) in two species of bees Euglossinae which were collected in two areas with distinct an tropic interferences and in two different seasons of the year in a reserve of Semidecidual Station Forest . The FA is frequently used to stimate stability in the development, besides being a good indicator of environmental impact levels. For each species studies 60 male species were chosen by chance, in whose wings four measurements were done so as to obtain a multi variable indices of size and indices of FA. There were no significant differences in the size of E. nigrita in the different places nor in the different seasons (F=0,568; P=0,454). The results for E. pleosticta indicated significant differences in the size of the bees in the two different seasons (F=20,947; P=0,001), but no differences were observed in the size in relation with the places (F = 0,109; P = 0,743). The male bees of E. pleosticta presented higher indices of size during the hot and wet season. The higher indices of rain and the consequent bigger availability of food during this season could have had an important role over the increase of biomass in E. pleosticta in this period. Regarding the FA, there were no significant differences in the analyzed characters between the places and seasons for both the E. nigrita and E. pleosticta. But for the E. pleosticta there were significant interaction between the season the M3 place. The collected bees in the hot and wet season which were found in the edge of the forest were more asymmetric than the bees collected in the cold and dry season which were found inside the forest. This indicates that the the weather and the a tropic interferences together influence the stability of development of the E. pleosticta. Nevertheless the same does not happen with the E. nigrita, which showed itself more resistant to the environmental interferences in its development program. Thus, its great plastic potential would lessen the stress conditions, allowing the maintenance of its development, as established in great or normal conditions, this way constituting a efficient mechanism of the development stability. / A sobrevivência dos organismos em ambientes heterogêneos e instáveis requer algumas vezes ajustes fisiológicos e morfológicos, envolvendo complexos mecanismos reguladores. Por outro lado, os organismos também possuem certa habilidade para resistir a distúrbios genéticos ou perturbações ambientais durante seu desenvolvimento, produzindo um fenótipo pré - determinado. O objetivo desse trabalho foi verificar se havia diferenças no tamanho e nos níveis de assimetria flutuante (AF) em duas espécies de abelhas Euglossinae coletadas em duas áreas com distintas interferências antrópica e em duas diferentes estações do ano em uma reserva de Floresta Estacional Semidecidual. A AF é freqüentemente utilizada pra estimar estabilidade do desenvolvimento, além de ser um bom indicativo dos níveis de impacto ambiental. Para cada espécie estudada foram escolhidos, aleatoriamente, 60 machos, em cujas asas foram efetuadas quatro medidas para obtenção de um índice multivariado de tamanho e um índice de AF. Não houve diferenças significativas no tamanho de E. nigrita entre os locais (F = 0,251; P= 0,618) e entre estações (F = 0,568; P= 0,454). Os resultados para E. pleosticta indicaram diferenças significativas no tamanho das abelhas entre as estações (F = 20,947; P= 0,001), mas não evidenciaram diferenças no tamanho em relação aos locais (F = 0,109; P = 0,743). Os machos de E. pleosticta apresentaram maior índice de tamanho durante a estação quente e úmida. O maior índice pluviométrico e a conseqüente maior disponibilidade de alimento durante esta estação podem ter tido um papel importante sobre o aumento de biomassa em E. pleosticta neste período. Em relação à AF, não houve diferenças significativas nos caracteres analisados entre os locais e entre as estações, tanto para E. nigrita quanto E. pleosticta. Mas, para E. pleosticta houve significativa interação entre estação*local em uma das medidas efetuadas. As abelhas coletadas na estação quente e úmida que se encontravam na borda da mata eram mais assimétricas que as abelhas da estação fria e seca que se localizavam no interior da mata. Isto indica que o clima e a interferência antrópica juntos influenciaram a estabilidade do desenvolvimento de E. pleosticta. Contrariamente, o mesmo não ocorreu com E. nigrita, que mostrou - se mais resistente às interferências ambientais no seu programa de desenvolvimento. Assim, seu grande potencial plástico tamponaria as condições de estresse, permitindo a manutenção do seu desenvolvimento, como o estabelecido em condições ótimas ou normais, constituindo assim um eficiente mecanismo de estabilidade do desenvolvimento. / Mestre em Genética e Bioquímica

O dimensionamento seguro e econômico de dissipadores de energia por ressalto hidráulico formado a jusante de vertedouros passa pela compreensão de como se processa a dinâmica do escoamento. Para que isso seja possível é necessário que sejam identificadas as características macroturbulentas do escoamento, tanto no que diz respeito aos valores médios quanto às parcelas flutuantes e extremas dos esforços de pressões atuantes junto ao fundo. Este trabalho, então, propõe a análise dos esforços hidrodinâmicos atuantes na estrutura hidráulica a partir de uma nova abordagem que preconiza que os esforços atuantes junto ao fundo devem ser avaliados como um somatório dos efeitos hidrodinâmicos ocasionados pelas distintas condições do escoamento. Dessa forma, foram avaliados individualmente os efeitos: (i) da curva de concordância vertical entre o perfil vertente e a bacia de dissipação e a sua influência sobre esta, (ii) do escoamento em regime rápido sobre um plano horizontal, (iii) da macroturbulência presente no ressalto hidráulico livre (tipo A) e (iv) do afogamento do ressalto hidráulico. Essa avaliação individualizada proporciona, em última instância, a identificação global dos esforços atuantes junto à estrutura hidráulica, conferindo sensibilidade a esta análise global a partir da identificação da influência de cada um dos efeitos atuantes e das respectivas consequências sobre a bacia de dissipação. O trabalho apresenta, assim, um método analítico de previsão de pressões médias, flutuantes e extremas atuantes ao longo de uma bacia de dissipação por ressalto hidráulico, quer este seja formado integralmente na bacia de dissipação, quer este seja formado parcialmente sobre o perfil vertente, condição predominante na operação de sistemas estruturais de dissipação de energia hidráulica. / To safely and economically design hydraulic jump energy dissipators downstream spillways the comprehension of the flow dynamics is needed. To achieve this it is needed to identify the macroturbulent characteristics of the flow, both the mean pressure values as well as the fluctuating and extreme pressures acting on the floor of the stilling basin. The present work proposes to analyze the hydrodynamic forces acting on the structures by means of a new approach which states that the pressures acting on the basin floor can be evaluates as the sum of hydrodynamic effects caused by the distinct flow conditions. The following effects were individually evaluated (i) transition from the spillway slope to the flat basin slope. (ii) supercrítical flow over a flat slope, (iii) macroturbulence present in a classic hydraulic jump (type A jump) and (iv) jump submergence. This individualized evaluation aims to identify the global forces acting on the spillway structure conferring sensitivity to the global analysis from the identification of each of the acting effects and its consequences. The present work relates an analytical method for predicting of mean, fluctuating and extreme pressures acting on a hydraulic jump stilling basin, be it formed integrally on the structure or partially over the spillway, usual condition in the basin operation.

The purpose of this research is to investigate and analyse some batch arrival queueing systems with Bernoulli scheduled vacation process and single server providing service. The study aims to explore and extend the work done on vacation and unreliable queues with a combination of assumptions like balking and re-service, reneging during vacations, time homogeneous random breakdowns and fluctuating modes of service. We study the steady state properties, and also transient behaviour of such queueing systems. Due to vacations the arriving units already in the system may abandon the system without receiving any service (reneging). Customers may decide not to join the queue when the server is in either working or vacation state (balking). We study this phenomenon in the framework of two models; a single server with two types of parallel services and two stages of service. The model is further extended with re-service offered instantaneously. Units which join the queue but leave without service upon the absence of the server; especially due to vacation is quite a natural phenomenon. We study this reneging behaviour in a queueing process with a single server in the context of Markovian and non-Markovian service time distribution. Arrivals are in batches while each customer can take the decision to renege independently. The non-Markovian model is further extended considering service time to follow a Gamma distribution and arrivals are due to Geometric distribution. The closed-form solutions are derived in all the cases. Among other causes of service interruptions, one prime cause is breakdowns. We consider breakdowns to occur both in idle and working state of the server. In this queueing system the transient and steady state analysis are both investigated. Applying the supplementary variable technique, we obtain the probability generating function of queue size at random epoch for the different states of the system and also derive some performance measures like probability of server‟s idle time, utilization factor, mean queue length and mean waiting time. The effect of the parameters on some of the main performance measures is illustrated by numerical examples to validate the analytical results obtained in the study. The Mathematica 10 software has been used to provide the numerical results and presentation of the effects of some performance measures through plots and graphs.

Apis mellifera é uma espécie de abelha bastante estudada sob diferentes perspectivas, tanto em pesquisas básicas como aplicadas. Possui uma natureza singular associada não só a interesses econômicos como produção de cera, mel, própolis, geléia real, pólen, mas também, por seu potencial agrícola como polinizador. Esta espécie tem sido alvo de muitos estudos morfométricos, principalmente pela sua importância ecológica, pela sua grande capacidade de adaptação, sua ampla distribuição e por serem capazes de se estabelecer eficientemente em diversos ambientes. A morfometria geométrica permite uma análise rigorosa da variação da forma de uma determinada estrutura em organismos de diversos tamanhos, principalmente utilizando métodos de estatística multivariada, além de ser capaz de avaliar a instabilidade no desenvolvimento de um organismo. O presente trabalho teve como objetivo estudar as variações da forma e tamanho em asas e corbículas de operárias de Apis mellifera, provenientes das 5 regiões geográficas do Brasil, utilizando análises morfogeométricas. A existência de padrões de variação de forma e tamanho das abelhas africanizadas no Brasil obtidos há 16 anos em estudo clássico realizado por Diniz-Filho e Malaspina, possibilitou uma análise espaço-temporal comparativa com os resultados obtidos utilizando recursos tecnológicos atuais para a avaliação de dados morfométricos, bem como, verificar por meio das análises de assimetria flutuante a plasticidade fenotípica no tamanho e forma da asa e corbícula dessa espécie, possibilitou ainda, avaliar se condições adversas relacionadas às ações antrópicas influenciam no aumento de desvios na simetria bilateral desses caracteres morfológicos. Foi realizada uma amostragem abrangendo as 5 regiões geográficas do Brasil, pela forma das asa e análises multivariadas verificou-se que existe um padrão geográfico entre as populações de Apis mellifera no Brasil (P < 0,001). Essas variações geográficas podem ser devidas à grande extensão territorial, além da possível associação das diferenças entre ecorregiões. Verificou-se, também, a presença de assimetria flutuante na forma das asas e das corbículas de Apis mellifera em todas as populações estudadas, porém, na análise multivariada e assimetria do tamanho não obteve significância em algumas populações, constatando-se que para estudo de assimetria e distribuição populacional a forma da asa e das corbículas é a análise mais indicada e que apresenta maior precisão. / Apis mellifera is bee specie very studied under different perspectives, as for basic studies to applied ones. They have a singular nature, not only associated to economic issues as wax, honey, propolis, royal jelly and pollen production, but also for their agricultural potential as pollinators. This specie has been long aimed for morphometric studies, because of its ecological importance, easy capacity of adaptation, large distribution and for being able of efficient establishment in diverse environments. The geometric morphometric allows rigorous analyses in shape variation of a given structure in organism of diverse sizes, especially when using multivariate statistics methods, enabling the evaluation of instability in the development of an organism. The present study aim the variations of shape and size in wings and pollen basket from workers of Apis mellifera, acquired at 5 geographic regions of Brazil, using morphogeometric analyses. The existence of variation patters in shape and size of Africanized bees in Brazil, obtained 16 years ago in classic study made by Diniz-Filho and Malaspina, made possible a comparative spatialtemporal analyses with the results obtained in this study, using updated technology resources for evaluation of morphometric data, as well as the phenotypic plasticity exam of size and shape in wings and pollen basket of this specie, using fluctuating asymmetric analysis, and evaluate if diverse conditions made by anthropomorphic actions has influence on the deviation increase among bilateral symmetry of this morphological characters. The sample was made including 5 geographic regions of Brazil. By the wings size shape and multivariate analyses, it was verified the existence of a geographic pattern among Brazilian Apis mellifera populations (P< 0,001). Those geographical variations may be caused due to the big territorial expansion, alongside with the possible association of different ecoregions. It was also verified floating asymmetric in the shape of wings and pollen basket from Apis mellifera in all studied populations, however, in the multivariate analyses the asymmetry in shape was not significant in some populations, showing that, for studies of asymmetry and populational distribution, the shape of wings and pollen basket is the most indicated and precise analyses.

O dimensionamento seguro e econômico de dissipadores de energia por ressalto hidráulico formado a jusante de vertedouros passa pela compreensão de como se processa a dinâmica do escoamento. Para que isso seja possível é necessário que sejam identificadas as características macroturbulentas do escoamento, tanto no que diz respeito aos valores médios quanto às parcelas flutuantes e extremas dos esforços de pressões atuantes junto ao fundo. Este trabalho, então, propõe a análise dos esforços hidrodinâmicos atuantes na estrutura hidráulica a partir de uma nova abordagem que preconiza que os esforços atuantes junto ao fundo devem ser avaliados como um somatório dos efeitos hidrodinâmicos ocasionados pelas distintas condições do escoamento. Dessa forma, foram avaliados individualmente os efeitos: (i) da curva de concordância vertical entre o perfil vertente e a bacia de dissipação e a sua influência sobre esta, (ii) do escoamento em regime rápido sobre um plano horizontal, (iii) da macroturbulência presente no ressalto hidráulico livre (tipo A) e (iv) do afogamento do ressalto hidráulico. Essa avaliação individualizada proporciona, em última instância, a identificação global dos esforços atuantes junto à estrutura hidráulica, conferindo sensibilidade a esta análise global a partir da identificação da influência de cada um dos efeitos atuantes e das respectivas consequências sobre a bacia de dissipação. O trabalho apresenta, assim, um método analítico de previsão de pressões médias, flutuantes e extremas atuantes ao longo de uma bacia de dissipação por ressalto hidráulico, quer este seja formado integralmente na bacia de dissipação, quer este seja formado parcialmente sobre o perfil vertente, condição predominante na operação de sistemas estruturais de dissipação de energia hidráulica. / To safely and economically design hydraulic jump energy dissipators downstream spillways the comprehension of the flow dynamics is needed. To achieve this it is needed to identify the macroturbulent characteristics of the flow, both the mean pressure values as well as the fluctuating and extreme pressures acting on the floor of the stilling basin. The present work proposes to analyze the hydrodynamic forces acting on the structures by means of a new approach which states that the pressures acting on the basin floor can be evaluates as the sum of hydrodynamic effects caused by the distinct flow conditions. The following effects were individually evaluated (i) transition from the spillway slope to the flat basin slope. (ii) supercrítical flow over a flat slope, (iii) macroturbulence present in a classic hydraulic jump (type A jump) and (iv) jump submergence. This individualized evaluation aims to identify the global forces acting on the spillway structure conferring sensitivity to the global analysis from the identification of each of the acting effects and its consequences. The present work relates an analytical method for predicting of mean, fluctuating and extreme pressures acting on a hydraulic jump stilling basin, be it formed integrally on the structure or partially over the spillway, usual condition in the basin operation.

Cette thèse étudie l’influence des fluctuations de l’environnement au cours de l’évolution sur l’architecture fonctionnelle des protéines.L’apparition de groupes restreints d’acides aminés – les secteurs, possédant des propriétés particulières tant du point de vue structurel et évolutif que fonctionnel ne trouve en effet pas d’explication simple dans le paradigme classique de la physique des protéines. Nous avons donc choisi d’étudier le rôle de l’histoire évolutive dans la construction de cette architecture particulière et des propriétés qui en découlent.Nous avons pour cela construit un modèle de protéine fonctionnelle inspiré des modèles de réseaux élastiques, que nous avons soumis à une évolution in silico en variant au cours du temps, avec différentes fréquences, la fonction recherchée. Nous avons montré que ces fluctuations induisent une concentration semblable à celle observée dans les protéines et avons pu déterminer les paramètres clés contrôlant ce phénomène. Nous avons finalement abordé le lien entre la statistique temporelle de l’environnement et l’apparition de différents secteurs indépendants. / This thesis studies the influence of an evolutionary fluctuating environment on the functional architecture of proteins.The appearance of restricted groups of amino acids – sectors, with particular functional, evolutional and structural properties has no simple explanation in the classical paradigm of proteins physics. So we choose to study the role of evolutionary history on the construction of this particular architecture and the resulting properties.We have thus constructed a model of functional protein inspired by the elastic network models, that we have evolved in silico while temporarily varying the targeted function with various frequencies. We have shown that these fluctuations induce a form of sparsity close to that observed in proteins and has identified the key parameters of this phenomenon. We finally investigate the link between the temporal statistics of the environment and the appearance of different independent sectors.

Condition monitoring is very important for critical assets such as gearboxes used in the power and mining industries. Fluctuating operating conditions are inevitable for wind turbines and mining machines such as bucket wheel excavators and draglines due to the continuous uctuating wind speeds and variations in ground properties, respectively. Many of the classical condition monitoring techniques have proven to be ine ective under uctuating operating conditions and therefore more sophisticated techniques have to be developed. However, many of the signal processing tools that are appropriate for uctuating operating conditions can be di cult to interpret, with the presence of incipient damage easily being overlooked. In this study, a cost-e ective diagnostic methodology is developed, using machine learning techniques, to diagnose the condition of the machine in the presence of uctuating operating conditions when only an acceleration signal, generated from a gearbox during normal operation, is available. The measured vibration signal is order tracked to preserve the angle-cyclostationary properties of the data. A robust tacholess order tracking methodology is proposed in this study using probabilistic approaches. The measured vibration signal is order tracked with the tacholess order tracking method (as opposed to computed order tracking), since this reduces the implementation and the running cost of the diagnostic methodology. Machine condition features, which are sensitive to changes in machine condition, are extracted from the order tracked vibration signal and processed. The machine condition features can be sensitive to operating condition changes as well. This makes it difficult to ascertain whether the changes in the machine condition features are due to changes in machine condition (i.e. a developing fault) or changes in operating conditions. This necessitates incorporating operating condition information into the diagnostic methodology to ensure that the inferred condition of the machine is not adversely a ected by the uctuating operating conditions. The operating conditions are not measured and therefore representative features are extracted and modelled with a hidden Markov model. The operating condition machine learning model aims to infer the operating condition state that was present during data acquisition from the operating condition features at each angle increment. The operating condition state information is used to optimise robust machine condition machine learning models, in the form of hidden Markov models. The information from the operating condition and machine condition models are combined using a probabilistic approach to generate a discrepancy signal. This discrepancy signal represents the deviation of the current features from the expected behaviour of the features of a gearbox in a healthy condition. A second synchronous averaging process, an automatic alarm threshold for fault detection, a gear-pinion discrepancy distribution and a healthy-damaged decomposition of the discrepancy signal are proposed to provide an intuitive and robust representation of the condition of the gearbox under uctuating operating conditions. This allows fault detection, localisation as well as trending to be performed on a gearbox during uctuating operation conditions. The proposed tacholess order tracking method is validated on seven datasets and the fault diagnostic methodology is validated on experimental as well as numerical data. Very promising results are obtained by the proposed tacholess order tracking method and by the diagnostic methodology. / Dissertation (MEng)--University of Pretoria, 2016. / Mechanical and Aeronautical Engineering / MEng / Unrestricted

Conventional gearbox vibration monitoring techniques are based on the assumption that changes in the measured structural response are caused by deterioration in the condition of the gears in the gearbox. However, this assumption is not valid under fluctuating load conditions, since the fluctuating load will amplitude modulate the measured vibration signal and cause the rotational speed of the system to change. In general monitoring of machines subject to fluctuating load conditions is dealt with by considering the constant load conditions on gearboxes or during free rotational tests. The need to monitor the condition of large gearboxes in mineral mining equipment has attracted greater interest in order to improve asset management. An inherent need for signal processing techniques, with the ability to indicate degradation in gear condition, under fluctuating load conditions exist. Such techniques should enable the online monitoring of gearboxes that operate under fluctuating load conditions. A continued flow of up to date information should consequently be available for asset and production management. With this research, a load demodulation normalisation procedure was developed to remove the modulation caused by fluctuating load conditions, which obscures the detection of an incipient gear fault conditions. A rotation domain averaging technique is implemented which combines the ability of computer order tracking and time domain averaging to suppress the spectral smearing effect caused by the fluctuation in speed, as well as to suppress the amplitude of the vibration which is not synchronous with the rotation of the gear shaft. It is demonstrated that the instantaneous angular speed of a gearbox shaft can be utilised to monitor the condition of the gear on the shaft. The instantaneous angular speed response measurement is less susceptible to phase distortion introduced by the transmission path when compared to conventional gearbox casing vibration measurements. A phase domain averaging approach was developed to overcome the phase distortion effect of the transmission path under fluctuating load conditions. The load demodulation normalisation and rotation domain averaging signal processing procedures were applied to both the conventional gearbox casing vibration and instantaneous angular speed measurements prior to the calculation of a smoothed pseudo Wigner-Ville distribution of the data. Statistical parameters such as the energy ratio were calculated from the distribution. These parameters could be monotonically trended under different load conditions to indicate the degradation of gear conditions. / Thesis (PhD (Mechanical Engineering))--University of Pretoria, 2005. / Mechanical and Aeronautical Engineering / unrestricted