A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy. / A theoretical and experimental treatment of fire processes in fuel-Lined, ventilated passages is presented. Initially a radially well mixed axial flow condition is considered. Experiments are first performed in non-stratified flow conditions where fire propagation and gas temperature histories are acquired from liquid and solid fuelled fires. Theory and experiment;display transient fire propagation for typical duct fire scenarios where initial fuel mass Loading is constant with respect to duct length. ( Abbreviation abstract ) / AC2017

As pesquisas com resinagem de árvores de espécies de pinus têm mostrado o efeito de fatores que afetam a produção e a qualidade da resina, relacionado com as espécies, variabilidade genética, taxa de crescimento, idade, manejo florestal, etc. As práticas de extração da goma-resina, a concentração, freqüência da aplicação de estimulantes químicos, época de abertura dos painéis, etc., têm sido, da mesma forma, analisadas. No entanto, há necessidade do desenvolvimento de pesquisas direcionadas ao estudo da formação e da estrutura do lenho e dos canais de resina das árvores de pinus. Pelo exposto, o presente trabalho teve como objetivos a caracterização da estrutura anatômica do lenho, dos anéis de crescimento e dos canais de resina, através de metodologias de histologia e de densitometria de raios X, de amostras de árvores de Pinus caribaea var. hondurensis resinadas e não resinadas, de três classes de diâmetro. Árvores de pinus, de plantação florestal instalada em 1969, na Estação Ecológica Experimental de Itirapina, do Instituto Florestal do Estado de São Paulo, foram mensuradas e estratificadas em três classes de diâmetro do tronco. As árvores de pinus têm sido resinadas desde 2004, com a abertura de dois painéis simultâneos e opostos. Sessenta amostras do lenho das árvores de pinus foram extraídas do tronco das árvores através de método não destrutivo e, em laboratório, (i) analisada e descrita a estrutura anatômica macro e microscópica do lenho; (ii) caracterizados os anéis de crescimento e determinada a densidade aparente do lenho por densitometria de raios X; (iii) caracterizados e descritos os canais de resina axiais e radiais e sua interconexão. Os resultados das análises evidenciaram que (i) a estrutura anatômica macro e microscópica do lenho e dos anéis de crescimento é característica da espécie; (ii) os anéis de crescimento falsos ocorrem nos lenhos inicial e tardio dos anéis de crescimento anuais devido as variações climáticas; (iii) a análise dos anéis de crescimento demonstrou que as árvores têm 38 anos, comprovada pela data de plantio; (iv) o comprimento e a espessura da parede das traqueídes não diferiram nas três classes de diâmetro do tronco; (v) a largura e o diâmetro do lume das traqueídes mostraram diferenças significativas, com maiores valores na classe de maior diâmetro do tronco; (vi) a densitometria de raios X possibilitou a demarcação dos limites dos anéis de crescimento e a determinação da freqüência dos canais de resina axiais; (vii) a densidade aparente média do lenho mostrou diferença significativa entre as árvores da classe de diâmetro alta em relação as das classes média-baixa; (viii) os canais de resina axiais localizam-se em maior freqüência no lenho tardio e apresentaram maior diâmetro de menor classe de diâmetro; (ix) as características do lenho e dos canais de resina nas faces testemunha e resinada não mostraram diferenças significativas. / The research on resin tapping trees with pine species have shown the effect of factors that affect the production and quality of resin, related with the species, genetic variability, growth rate, age, forest management, etc.. The gum-resin extraction practices, the concentration, frequency of application of chemical stimulants, the time of year that panels are opening, etc., have been in the same manner, discussed. However, there is need for further research directed to study the formation and structure of the wood and resin canals from the pine trees. Therefore, this work aimed to characterize the anatomical structure of wood, the tree rings and resin canals, through methodology of histology and X-ray densitometry, of resin tapped and not resin tapped Pinus caribaea var. hondurensis trees samples, of three diameter classes. Pine trees, in forest plantation established in 1969, in the Ecological Experimental Station of Itirapina, from the Forestry Institute of São Paulo State, were measured and stratified into three classes of diameter of the trunk. The pine trees have been resin tapped since 2004, with the opening of two simultaneous and opposing panels. Sixty samples of pine wood trees were extracted from the tree trunk through a non-destructive method, and in the laboratory, (i) examined and described the macro- and microscopic anatomical structure of wood, (ii) characterized the tree rings and determined the wood apparent density by X-ray densitometry, (iii) characterized and described the ducts for axial and radial resin and its inter-connection. The test results showed that (i) the macro- and microscopic anatomical structure of wood and the tree rings are characteristic of the species, (ii) the false tree rings occur in the early wood and latewood of the tree rings due to climate change (iii) the analysis of tree rings showed that 38 years have proven the date of planting of the trees, (iv) the length and thickness of tracheids wall did not differ in the three diameter classes of the trunk, (v) the tracheids lumen width and diameter showed significant differences, with higher values in the larger diameter class trunk, (vi) the Xray densitometry allowed the demarcation of the tree rings limits and determination of the axial resin canals frequency (vii) the wood apparent density average was significantly different between the trees in high class diameter from the medium-low, (viii) the axial resin canals can be found more frequently in the latewood and had larger diameter in the lowest diameter class, (ix) the wood and resin canals characteristics from the resin tapped and no resin tapped faces did not show significant differences.

Este trabalho apresenta um estudo sobre o escoamento de ar em dutos com múltiplas saídas que são identificados como caixas sopradoras, quando instalados em máquinas desaguadoras de celulose. Estas caixas auxiliam o processo de secagem conduzindo ar aquecido até um conjunto de orifícios que produzem jatos que são impingidos sobre as folhas de celulose fabricadas. É realizada revisão bibliográfica abordando processos e equipamentos de secagem, com foco no escoamento de ar, métodos para solução numérica de escoamentos, seus modelos e parâmetros, e abordagem semi-empírica para fluxos de ar na saída de dutos. O escoamento do ar no interior da caixa sopradora e nos jatos de saída são estudados através de simulação numérica, e de modelo semi-empírico. São propostas duas alternativas de geometria para estes dutos de modo que se garanta a maior uniformidade possível na vazão e na velocidade média do ar que saí através dos orifícios Na primeira alternativa considera-se que a seção transversal da caixa sopradora se mantém constante. Na segunda se considera que a seção transversal seja reduzida de modo uniforme ao longo da caixa sopradora. Um estudo experimental sobre o comportamento do escoamento de ar para caixas sopradoras em escala reduzida apresenta resultados que possibilitam validar um conjunto de valores numéricos obtidos na simulação e também estabelecer características para o escoamento de modo a atender o processo de secagem. Para cada alternativa são adotadas duas condições de vazão de ar. Os resultados obtidos pela da simulação numérica e modelagem semi-empírica validam um perfil geométrico adequado para que a caixa sopradora produza um conjunto de jatos nas suas saídas com valores de velocidade média. Um dos principais resultados foi obtido para a caixa com 275 orificios, na qual as velocidades médias estiveram dentro do intervalo de 32,5 m/s e 33,1 m/s, que representou um ótimo resultado em termos de balanceamento e uniformidade das vazões de ar. / This study presents an analysis about airflow in ducts with multiple outlets that are identified as blow boxes, when installed in pulp dewatering machines. These boxes work in the drying process leading heated air to a set of nozzles that produce air jets that are impinged against the pulp sheet. It is performed literature review about drying processes and equipment, with a focus on air flow, methods for numerical solution of airflows, their models and parameters, and semi-empirical approach about airflow at the outlets of the duct. The airflow inside the blow box and the output jets are studied by numerical simulation, and semi-empirical model. It is proposed two alternative geometries for these ducts in order to guarantee the greatest possible uniformity in flow rate, and in the average velocity of air jets. In the first alternative is considered that the cross section of the blow box remains constant. In the second one it is considered that the cross section is reduced uniformly along the blow box. An experimental study about the behavior of the airflow in blow boxes, using scaled models, presents results that can validate a set of numerical values obtained in the simulation and also establish characteristics for the drying process. For each alternative two conditions of airflow are adopted. The results obtained through numerical simulation and semi-empirical modeling validates an appropriate geometrical profile for the blow box in order to set the values of average speed within the range required by the drying process. One of the principal results, obtained for the case of boxes with 275 holes, was the average speed within the range of 32,5 m/s and 33,1 m/s, this range represents a great result in tterms of balance and uniformity of air flow.

Made available in DSpace on 2017-07-10T14:17:20Z (GMT). No. of bitstreams: 1 Lana_Branai.pdf: 2297634 bytes, checksum: 8dbbaa1b059e5e38dcdd38ba4a303557 (MD5) Previous issue date: 2016-03-04 / Nowadays, the search for beauty, has caused health problems associated with the use of anabolic androgenic steroid (AAS) and even strenuous exercise, and the male reproductive system is the subject of studies to be sensitive to changes in the concentration of this type of hormone; these changes may also occur with increasing age, causing changes in androgen-dependent organs, like the epididymis. This study aimed to verify if treatment with AAS associated or not to exercise, in Sprague-Dawley rats alters the morphology of the epididymis in adult rats and its chronic effects in the elderly. The training was conducted by jumping into the water, weighing overloading, being considered as resistance exercise in water. The AAS administration occurred by intramuscular injection of nandrolone decanoate (10 mg / kg / week). Epididymal samples were subjected by histological routine of hematoxylin and eosin for morphological and morphometric analysis. It was analyze all parts of the epididymis (initial segment, caput, corpus and cauda) of 56 Sprague-Dawley rats, virgins, with 13 weeks old, divided into eight groups with seven animals each: GC - adults and sedentary; GCi - elderly and sedentary; GN - adults, sedentary treated with AAS; GNi - elderly, sedentary treated with AAS; GE - adults treated with exercise; GEi - elderly treated with exercise; GNE - adults, exercise and treatment with AAS; GNEi - elderly, exercise and treatment with AAS. The results show significant changes in duct diameters; the GE was lower when compared to other groups, and the groups that were used anabolic steroids, had a larger diameter than the other, and these changes occurred mainly in the initial segments. The epithelial height in the initial segment was also considered higher in the groups that administered AAS. The elderly groups tend to return to normal, increasing the parameters of epithelial height and diameter when these were decreased, and lowering them when they were enlarged when compared with the related adult group (with common variable), except at the tail of GNEi. As the results of this study, we can conclude that both treatment in adulthood, with exercise and the use of AAS, changes morphometric and morphological parameters of the epididymis, and its chronic effects can be diminished with age. / Atualmente, a procura pela beleza estética, tem causado problemas de saúde associados ao uso de esteroides androgênicos anabolizantes (EAAs) e até mesmo a exercícios físicos intensos. O sistema genital masculino é alvo de estudos por ser sensível a mudanças na concentração desse tipo de hormônio; essas alterações também podem ocorrer com o aumento da idade, influenciando órgãos androgênio-dependentes, como o epidídimo. Nesse sentido, objetivou-se com esse estudo, verificar se o tratamento com EAAs associado ou não ao exercício físico resistido, em ratos Sprague-Dawley, altera a morfologia do Epidídimo em ratos adultos e seus efeitos a longo prazo em idosos. Foram analisadas todas as porções dos epidídimos (segmento inicial, cabeça, corpo e cauda) de 56 ratos, virgens, da linhagem Sprague-Dawley (com 13 semanas de vida ao iniciarem o experimento), separados em oito grupos com sete animais cada: GC - adultos e sedentários; GCi - idosos e sedentários; GN - adultos, sedentários, tratados com EAA; GNi - idosos, sedentários, tratados com EAA; GE - adultos tratados com exercício; GEi - idosos tratados com exercício; GNE - adultos, exercício e tratamento com EAA; GNEi - idosos, exercício e tratamento com EAA. O treinamento realizado foi exercício resistido em meio aquático (através de saltos na água, com sobrecarga) com duração de oito semanas (três vezes na semana). A administração de EAAs ocorreu pela aplicação intramuscular de Decanoato de Nandrolona (10 mg/kg/semana) também durante oito semanas (duas vezes na semana). Amostras epididimárias passaram pela rotina histológica de hematoxilina e eosina para análise morfológica e morfométrica. Os resultados mostraram alterações significativas nos diâmetros de ductos, sendo que o GE foi menor quando comparado ao controle, e, nos grupos em que foram utilizados anabolizantes, tiveram diâmetro aumentado significativamente, e essas alterações ocorreram principalmente nos segmentos mais iniciais. A altura epitelial, no segmento inicial, também foi maior nos grupos em que foi utilizado anabolizante. Os grupos idosos tenderam a retornar a normalidade, aumentando os parâmetros de altura e diâmetro quando esses estavam diminuídos, e diminuindo-os quando estavam aumentados em comparação ao grupo adulto relacionado (com variável em comum), a não ser na cauda, do GNEi, em que houve aumento significativo. Achados morfológicos indicaram presença de debris celulares em lúmen (GN e GNEi) e infiltrados intersticiais (GN, GNE, GE e GCi). Conforme os resultados desse estudo, pôde-se concluir que tanto o tratamento na fase adulta com exercício, quanto à utilização de EAAs altera parâmetros morfométricos e morfológicos do epidídimo, e que seu efeito crônico pode ser diminuído com a idade.

Bibliography : leaves 237-251. / x, 251 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1994

To be able to handle tomorrows need for limited energy consumption we need to reduce our use of energy. The building sector stands for around 40 % of all energy consumption in the society. The government has put up a goal to reduce the energy consumption in our buildings with 20 % by year 2020 and 50 % by year 2050 compared with year 1995. To be able to do reach that goal we need a more energy efficient building stock. The main part of the energy used in our buildings is used for space heating. By installing ventilation systems with heat recovery on the exhaust air it is possible to use the heat-energy in the exhaust air to warm up the incoming air. This can contribute to a reduction in energy use. A ventilation system with heat recovery on the exhaust air is space demanding and there can be problems with finding enough space to do the installation indoors. Therefore it can be an advantage to place the aggregate and the ducts on the outside of the buildings climate shell. A placement exterior of the buildings climate shell or in an unheated space leads to thermal heat losses. The aim with this essay is to investigate how significant the heat losses are on exterior placed ventilation systems. The investigation has been done with help of theoretical calculations and measurements of the temperature difference in the ventilation ducts. Analysis has been made on life cycle costs on how to reduce the heat losses in an economic manner. To buildings, Höstvägen 14 and 22 in Växjö, which have been equipped with exterior placed ventilation systems have been studied. The two buildings have two different types of installation of the ducts. Our result shows that the heat losses through the ventilation systems on Höstvägen 14 and 22 are significant. The majority of the losses occur in the ducts. In the aggregate the thermal bridges in the framework accounts for the larger part.

Unsteady shock wave propagation through ducts has many applications, ranging from blast wave shelter design to advanced high-speed propulsion systems. The research objective of this study was improved fundamental understanding of the transient flow structures during unsteady shock wave propagation through rectangular ducts with varying cross-sectional area. This research focused on the fluid dynamics of the unsteady shock-induced flow fields, with an emphasis placed on understanding and characterizing the mechanisms behind flow compression (wave structures), flow induction (via shock waves), and enhanced mixing (via shock-induced viscous shear layers). A theoretical and numerical (CFD) parametric study was performed, in which the effects of these parameters on the unsteady flow fields were examined: incident shock strength, area ratio, and viscous mode (inviscid, laminar, and turbulent). Two geometries were considered: the backward-facing step (BFS) geometry, which provided a benchmark and conceptual framework, and the splitter plate (SP) geometry, which was a canonical representation of the engine flow path. The theoretical analysis was inviscid, quasi-1D and quasi-steady; and the computational analysis was fully 2D, time-accurate, and viscous. The theory provided the wave patterns and primary wave strengths for the BFS geometry, and the simulations verified the wave patterns and quantified the effects of geometry and viscosity. It was shown that the theoretical wave patterns on the BFS geometry can be used to systematically analyze the transient, 2D, viscous flows on the SP geometry. This work also highlighted the importance and the role of oscillating shock and expansion waves in the development of these unsteady flows. The potential for both upstream and downstream flow induction was addressed. Positive upstream flow induction was not found in this study due to the persistent formation of an upstream-moving shock wave. Enhanced mixing was addressed by examining the evolution of the unsteady shear layer, its instability, and their effects on the flow field. The instability always appeared after the reflected shock interaction, and was exacerbated in the laminar cases and damped out in the turbulent cases. This research provided new understanding of the long-term evolution of these confined flows. Lastly, the turbulent work is one of the few turbulent studies on these flows.

Heat transfer analysis of two-dimensional, incompressible, constant property, hydrodynamically developed, thermally developing, single phase laminar flow in microtubes and microchannels between parallel plates with negligible axial conduction is performed for constant wall temperature and constant wall heat flux thermal boundary conditions for slip flow regime. Fully developed velocity profile is determined analytically, and energy equation is solved by using finite difference method for both of the geometries. The rarefaction effect which is important for flow in low pressures or flow in microchannels is imposed to the boundary conditions of the momentum and energy equations. The viscous dissipation term which is important for high speed flows or flows in long pipelines is included in the energy equation. The effects of rarefaction and viscous heating on temperature profile and local Nusselt number are discussed. The results of the numerical method are verified with the well-known analytical results of the flow in macrochannels (i.e. Kn =0, Br =0) and with the available analytical results of flow in microchannels for simplified cases. The results show significant deviations from the flow in macrochannels.

[pt] O presente trabalho analisa a transferência de calor e a perda de carga em escoamento turbulento através das regiões anulares lisas e aletadas. Os coeficientes de transferência de calor foram obtidos experimentalmente, utilizando-se a teoria de trocadores de calor. Também foram determinados os coeficientes de perda de carga associados a cada uma das geometrias analisadas. Os experimentos foram realizados em um trocador de calor bi-tubular concêntrico. Água (fluído quente) escoava através do tubo interno, enquanto ar (fluido frio) fluía através da região anular. Medindo-se as vazões e temperaturas na entrada e saída da seção de teste do trocador de calor, obtém-se a efetividade da mesma e, consequentemente, o coeficiente global de transferência de calor (médio). As condições de contorno adotadas foram de temperatura uniforme na superfície externa do tubo interno e de isolamento térmico na superfície externa do tubo interno e de isolamento térmico na superfície externa da região anular. Com o objetivo de obter-se condições de escoamento completamente desenvolvido, o trocador de calor possui um comprimento, a montante da seção de testes, de aproximadamente trinta diâmetros hidráulicos. Os coeficientes de transferência de calor e de perda de carga são apresentados de forma adimensional, como função do número de Reynolds do escoamento, os resultados obtidos para as regiões anulares lisas e aletadas são comparados entre si. O propósito de tal comparação foi o de estudar a influencia das aletas na perda de carga e na taxa de transferência de calor. No caso das regiões aletadas, verifica-se que a eficiência das aletas influencia a transferência de calor. Deste modo, realizou-se uma análise bi-dimensional de transferência de calor nas aletas para obter-se a eficiência das mesmas e, consequentemente, a eficiência das regiões aletadas. Também é mostrado que o desempenho térmico da região depende principalmente do número de Nusselt e da eficiência da mesma. Tais parâmetros são apresentados, em última análise, como funções do número de Reynolds e da geometria do problema. / [en] The present work is concerned with the turbulent heat transfer and pressure drop in smooth and finned annular ducts. Average heat transfer coeeficients have been obtained by means of the heat exchanger theory. In addition, friction factors have also been determined. The experiments were performed by utiling four double-pipe heat exchangers. The average heat transfer coefficients, for air flowing in the annular section, were fertmined by measuring the overall heat transfer coefficients of the heat exchangers. In order to aatain fully developed conditions, the heat exchangers had a starting length of 30 hydrualic diameters. The thermal boundary conditions consisted of uniform temperature on the inner surface, the outer surface being insulate. The heat transfer coefficients and friction factors are presented in dimensinless forms, as functions of the Reynolds number of the fow. The results for smooth and finned annular ducts were compared. The purpose of such comparison was to study the influence of the fins on the pressure drop and heat transfer rate. In the case of the finned annular ducts, it is shown that fin efficiency has some influence on the heat transfer rates. Then a two-dimensional heat transfer analysis was performed in order to obtain the fin efficiency and the annular region efficiency. It is also shown that the overall thermal performance of finned surfaces depends mainly of the Nusselt number and on the region efficiency. These parameters are presented as functiond of the Reynolds number of the flow and the geometry of the problem.

Orientador: Silvana Moreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-11T08:53:13Z (GMT). No. of bitstreams: 1 Fonseca_RoneyJoseda_M.pdf: 1481408 bytes, checksum: 7f9822fbb599c31623b7b04f50171593 (MD5) Previous issue date: 2007 / Resumo: O objetivo deste trabalho foi monitorar e avaliar a emissão de fluoreto e de metais de dutos e fontes estacionárias de indústrias cerâmicas da região do Pólo Cerâmico de Santa Gertrudes (SP). Nos últimos anos houve um crescimento das empresas neste setor, causando reflexos ambientais nesta região responsável por 60% da produção de pisos esmaltados. O principal causador destes danos é o flúor na forma de fluoreto gasoso e ácido fluorídrico, comumente encontrado no solo e na argila utilizada na fabricação de pisos e artefatos cerâmicos. No período de 2004 a 2007 foram coletadas amostras dos gases emitidos por diversas indústrias cerâmicas desta região. Os compostos a base de flúor foram analisados por potenciometria e alguns metais pela técnica de fluorescência de raios X por reflexão total com radiação síncrotron. Altas concentrações de elementos como Cromo, Níquel e Chumbo foram observadas nas amostras analisadas e, em valores superiores aos permitidos pela legislação. No que se refere à emissão de fluoreto total foi verificado que 61,5% das empresas monitoradas apresentaram valores de emissão acima do permitido (5,0 mg/Nm3). Foi verificado ainda que o fluoreto foi emitido principalmente na forma de fluoreto gasoso. Desta forma a problemática ambiental na região de Santa Gertrudes não está associada apenas à emissão de flúor, mas também está relacionada à presença de metais pesados presentes em altas concentrações nas emissões atmosféricas provenientes do setor cerâmico / Abstract: The purpose of this work was monitoring and evaluation the emissions of fluoride and metals of ducts and stationary sources from ceramics industries of Santa Gertrudes region (SP). In recent years there had been a growth of companies in this sector, causing environmental repercussions in this region responsible for 60% of the production of porcelain tiles. The main cause of these damages is fluorine as fluoride gaseous and fluoridric acid, commonly found in soil and clay used in the manufacture of ceramic artifacts. During 2004 until 2007 gaseous samples were collected in different industries. The fluorine compounds were analyzed by potentiometry method and some metals by X-ray fluorescence analysis. High concentrations of Chromium, Nickel and Lead were observed in the samples and the values were higher than the permitted by the Brazilian legislation. In relation to fluoride emission 61,5% of the industries monitored showed values above the established by the legislation (5.0 mg/Nm3). In this way the environmental pollution in Santa Gertrudes region was not associated just to fluorine emission but also with the heavy metals present in high concentrations in the atmospheric emissions from stationary sources of ceramic industries / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil