Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-15T13:18:20Z No. of bitstreams: 1 Fábio Ricardo de Oliveira de Souza.pdf: 10103280 bytes, checksum: 4e2fd0c8307348f7e9098749cafe8b73 (MD5) / Made available in DSpace on 2015-07-15T13:18:20Z (GMT). No. of bitstreams: 1 Fábio Ricardo de Oliveira de Souza.pdf: 10103280 bytes, checksum: 4e2fd0c8307348f7e9098749cafe8b73 (MD5) Previous issue date: 2013-01-31 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / Este trabalho apresenta um estudo numérico sobre características de escoamento e transferência de calor em tubo evacuado. A abordagem numérica foi realizada com o software comercial ANSYS-CFX. O modelo numérico adotado é tridimensional e é composto pelas equações da conservação da massa, quantidade de movimento e energia. A malha computacional é do tipo hexaédrica, com refinamento nas regiões de maiores gradientes térmicos e fluidodinâmicos. O modelo implementado foi validado com resultados numéricos da literatura e um estudo de caso foi realizado, considerando variações do ângulo de inclinação do tubo, da variação da taxa de transferência de calor para o tubo e da variação da temperatura da água proveniente do reservatório térmico. Também foram avaliadas duas hipóteses: uma considerando propriedades físicas da água constantes e a outra com propriedades variáveis com a temperatura. Comparações são apresentadas para campos de velocidade e temperatura, vazão mássica e números de Nusselt e de Reynolds. O comparativo entre os resultados obtidos com a hipótese de propriedades constantes, com aqueles obtidos com propriedades variáveis mostra diferenças significativas entre eles, apontando a importância do uso de propriedades variáveis neste tipo de simulação numérica. Os resultados dos estudos paramétricos indicam que o incremento da vazão mássica e da temperatura média de saída do fluido é diretamente proporcional ao incremento do ângulo de inclinação, da taxa de transferência de calor e da temperatura do reservatório térmico. / This work presents a numerical study on characteristics of flow and heat transfer in an evacuated tube. The numerical approach was performed with the commercial software ANSYS-CFX. The numerical model adopted is three-dimensional and consists of the mass, momentum and energy equations. The computational mesh is hexaedrical, with refinement in regions of higher thermal and fluid gradients. The implemented model was validated with numerical results of literature and a case study was conducted considering inclination angle, rate of heat transfer and water temperature from the thermal reservoir. Also were evaluated two hypotheses: one considering constant physical properties of water and the other with properties varying with temperature. Comparisons are presented for velocity and temperature fields, mass flow and Nusselt and Reynolds numbers. The comparison between the results obtained with the hypothesis of constant properties, with those obtained with variable properties, shows significant differences between them, pointing out the importance of using variable properties in this type of numerical simulation. The results of the parametric studies indicate that the increment of the mass flow and average temperature of the fluid is directly proportional to the inclination angle, the rate of heat transfer and the temperature of the thermal reservoir.

O coletor solar de tubos evacuados une uma alta absortividade de radiação solar a um ótimo grau de isolamento térmico. Estas características, aliadas a um custo relativamente baixo, fazem deste tipo de coletor o mais utilizado no mundo. Por isso, diversos tipos de abordagens estão sendo adotadas para descrever seu comportamento térmico. Nesta linha, este trabalho foi desenvolvido através de abordagem experimental e teórica, sendo a última subdividida em numérica por CFD e analítica. A abordagem experimental contou com a construção de uma bancada para medida de temperatura e radiação, em um coletor de 24 tubos evacuados acoplados em um reservatório de 178 L. A abordagem por CFD utilizou um modelo tridimensional transiente. Com o modelo numérico validado, utilizando resultados experimentais, simularam-se diferentes condições de operação, em termos de ângulo de inclinação, fluxo de calor sobre o coletor, tamanho do reservatório e temperatura de entrada da água. Em relação à abordagem analítica, esta é dividida em: modelo de irradiância, modelo do tubo e modelo do reservatório. O modelo de irradiância determina a distribuição da radiação solar ao longo da circunferência do tubo. Parte desta radiação é absorvida pelo coletor e transferida para água. Esta quantidade é determinada com o modelo do tubo, que é baseado no método de resistências térmicas. O modelo do reservatório descreve o comportamento térmico da água em seu interior, tanto em aquecimento quanto em resfriamento, analisando a interação energética com o coletor e com o meio externo. O desenvolvimento do modelo do tubo passa pela avaliação da vazão mássica entre o tubo e o reservatório, além disso, o coeficiente de transferência de calor por convecção no interior do tubo deve ser determinado. Tais variáveis são determinadas a partir de uma correlação para o número de Reynolds, a qual foi obtida com resultados da avaliação por CFD e é função dos números de Nusselt, Grashof e Prandtl. A correlação proposta apresentou bom ajuste com os resultados numéricos. Com a bancada de ensaio experimental foram feitas medidas de temperatura da água no reservatório ao longo de alguns dias. Para as mesmas condições do experimento, a temperatura média da água no reservatório foi estimada com resultados da integração dos modelos de irradiância, do tubo e do reservatório. A diferença entre os resultados experimental e teórico foi de 4,8% para a energia acumulada. / The evacuated tube solar collector combines high solar radiation absorptivity to a great thermal insulation degree. These characteristics, combined with a relatively low cost, make this type of collector the most used in the world. Therefore, various types of approaches are being adopted to describe its thermal behavior. In this way, this work was developed through experimental and theoretical approaches, the latter being subdivided into numeric, by CFD, and analytical analysis. For the experimental approach a test bench was built. The tests was carried on a solar collector with 24 evacuated tubes coupled to a 178 L tank, measuring temperature and solar radiation. The CFD approach used a transient three-dimensional model. After the numerical model validation using experimental data, simulations was carried over different operating conditions in terms of angle, heat flux on the collector, tank size and water inlet temperature. The analytical approach is divided into: irradiance model, tube model and tank model. The irradiance model determines the irradiance distribution of solar radiation along the circumference of the tube. Part of this radiation is absorbed by the collector and transferred to water, this amount is determined with the tube model, using the thermal resistance method. The tank model describes the thermal behavior of inside water, both in heating and in cooling, analyzing energy interaction with the collector and the external environment. The development of the tube model involves the assessment of the mass flow rate between the tube and the tank, furthermore the convection heat transfer coefficient inside the tube must be determined. These variables are determined from a correlation for the Reynolds number, which was obtained with evaluation results by CFD. Proposed Reynolds number is a function of the Nusselt, Prandtl and Grashof numbers. The correlation presented a good agreement with the numerical results. Using the experimental test bench the water temperature was measured into the tank over a few days. For the same experiment conditions, the average temperature of the water into the tank was estimated by results of integration of irradiance, tube and tank models. The difference between the experimental and theoretical results was 4.8% for the accumulated energy.

A new way of adhering woven textile to a nonwoven backing was explored, the end product in mind being a sound absorbent panel. Today a hot melt adhesive is sprayed on the nonwoven with woven decorating textile put on top before compression molding. This method results in an uneven layer of adhesive with the consequence of decorating textile detaching from the nonwoven and thereby a high number of discarded products. The report investigates the possibility of using a bicomponent fiber as the adhesive. This would guarantee an even layer of adhesive and make the manufacturing process one step shorter. A bicomponent fiber of core/sheath construction with a low melting polymer in the sheath was incorporated in the nonwoven upon fabrication. In the main bulk of the nonwoven a smaller ratio of bicomponent to normal polyester fiber was used, enough to stabilize the nonwoven. For the top layer of the nonwoven a higher ratio was chosen. As the nonwoven is then compression molded under heat together with the decorating textile, the low melting sheath of the bicomponent fiber will melt and create bonds within the nonwoven as well as to the textile. The ratio in the top layer was varied as well as the pressure in compression molding. The adhesion strength between nonwoven and decorating textile was tested, and the sound absorbing properties of the different manufactured samples were compared. The sound absorbing parameter of air flow resistance was tested and sound absorption was tested using impedance tube with transfer function method. Further, a way of testing transmission loss was developed by the manufacturing of a custom built impedance tube, which was then compared to the transfer function method. The results showed that a higher bicomponent percentage gave higher sound absorption in lower frequencies, but a lower sound absorption in higher frequencies. The thickness of the samples gave a positive effect on the sound absorption in all frequencies. The conclusion is to recommend a thicker material, and choose bicomponent according to which frequencies that should be absorbed and what adhesion strength is needed for end product. / Program: Textilteknik

L’objectif de cette thèse est d’étudier la possibilité de caractériser le coefficient de frottement par un modèle analytique. Tout d’abord, le modèle analytique (Orban-Hu,2007) a été programmé à l’aide du logiciel « Matlab » puis validé par simulation numérique à l’aide du logiciel « Ls-Dyna ». Ensuite, on a réalisé des essais expérimentaux afin de caractériser les propriétés mécaniques du cuivre d’une part et étudier la mise en forme de tubes par hydroformage de tubes. Par suite, le coefficient de frottement a été caractérisé aussi bien par le modèle analytique que par le test classique ‘pion sur disque’. Les simulations numériques avec les coefficients de frottement obtenus ont permis de valider les résultats issus des essais expérimentaux pour une matrice carrée. Les mêmes résultats ont été également obtenus pour d’autres configurations géométriques (section rectangulaire, trapézoïdale et trapèze.) / The objective of this thesis is to study the possibility of characterizing the friction coefficient by an analytical model. First, the analytical model (Orban-Hu, 2007) has been programmed using "Matlab» software and has been validated by numerical simulation using "LS-Dyna" software. Then, experimental tests were carried out in order i) to characterize the mechanical properties of copper and ii) to study the tube hydroforming in a square section. As a result, the friction coefficient was characterized by the analytical model and the pin-on-disk test. Then, the numerical simulation with the friction coefficients obtained allowed to validate the experimental results for a square section. The same findings were obtained using other die geometries (rectangular, trapezoidal and trapezoid-sectional die).

Essa tese teve como objetivo avaliar todos os casos de candidose sistêmica por Candida albicans identificadas através de kit comercial ID 32C® (bioMérieux), diagnosticados no Laboratório de Micologia da Santa Casa de Misericórdia de Porto Alegre/RS, durante o período de 1999 a 2009, buscando identificar a prevalência de C. dubliniensis, bem como avaliar os fatores de virulência e diferença de perfil de suscetibilidade antifúngica entre os isolados clínicos. Foi realizado um levantamento clínico-epidemiológico dos casos incluídos no estudo, avaliando sexo, idade, manifestações clínicas, evolução, região proveniente do paciente, doença de base, condições predisponentes, utilização de corticóides e antibióticos e resposta ao tratamento recebido. Para a diferenciação das duas espécies utilizou-se testes fenotípicos (arranjo dos clamidosporos, teste de termotolerância, formação do tubo germinativo, crescimento em meio hipertônico e niger), molecular (espectrometria de massa) e genotípico (reação em cadeia da polimerase - PCR). Em adição, foi avaliada a eficácia do método de conservação das leveduras estocadas a -20ºC e comparamos quatro substratos (soro fresco, soro congelado, ágar e caldo Mueller-Hinton) para a prova do tubo germinativo. Determinou-se a produção da fosfolipase e proteinase em isolados incluídos no estudo. A atividade in vitro dos antifúngicos fluconazol, anfotericina B e anidulafungina frente aos isolados estudados foi determinada através da concentração inibitória mínima (CIM), a concentração fungicida mínima (CFM) e ponto de corte epidemiológico (ECV). Os casos de candidemia por C. albicans diagnosticados durante 10 anos ocorreram com maior frequência em pacientes adultos com presença de cateteres. Observamos que houve maior chance de ocorrência desta em pacientes oncológicos. O percentual de alta nos pacientes foi baixo. O método utilizado para a conservação de leveduras nesse estudo apresentou taxa de 70% de viabilidade. O ágar e o caldo Mueller-Hinton demonstraram sensibilidade de 90% e especificidade de 100%. Os isolados de C. albicans provenientes de hemocultivos apresentaram produção de fosfolipase em 78% e proteinase em 97% dos isolados. A espécie C. dubliniensis não foi identificada em isolados de hemocultivos, sendo todos os casos de candidemia por C. albicans. Os testes microcultivo em ágar fubá, espectrometria de massa, caldo niger e caldo hipertônico concordaram com o teste genotípico. Os isolados de C. albicans apresentaram maior suscetibilidade a anidulafungina, entretanto, os menores valores obtidos em 90% dos isolados (CIM90) foi pela anfotericina B. E através do ECV, os isolados poderiam ser resistentes ao fluconazol, demonstrando a importância da associação desses dois parâmetros. / The aim this tesis was to evaluate systemic candidiasis cases by Candida albicans through ID 32C® (bioMérieux), at Mycology Laboratory of the Santa Casa de Porto Alegre/RS, during 1999 to 2009, seeking to identify the C. dubliniensis prevalence, as well as evaluating the virulence factors and antifungal susceptibility profile difference of among isolates. The clinical and epidemiological survey was made through gender, age, clinical manifestations, evolution, patient's region, underlying disease, predisposing conditions, steroids and antibiotics use, and response to treatment. The phenotypic tests (tthermotolerance, germ tube, hypertonic and Niger medium), molecular (mass spectrometry) and genotypic (polymerase chain reaction – PCR) was used for two species identification. We also assessed if the mantainance of C. albicans stored at - 20ºC in a freezer with sterile distilled water was usefull.The four substrate (fresh and frozen serum, agar and broth Mueller-Hinton®) were used for germ tube formation and the phospholipase and proteinase activity were evaluated. The in vitro activity of fluconazole, amphotericin B and anidulafungin were compared through the minimum inhibitory concentration (MIC), the minimum fungicidal concentration (MFC) and epidemiological cutoff value (ECV). The candidemia cases by C. albicans for ten years occurred more frequently in adult and catheters use. We observed the more chance this occurrence in cancer patients. The survival percentage was low. The used method in the study for yeast stored had 70% of viability. The agar and broth Mueller-Hinton were 90% sensitivity and 100% specificity. The boodstream isolates of C. albicans produce virulence factors, such the germ tube production and hydrolytic enzymes (78% of phospholipase and 97% of protease) production. The C. dubliniensis was not identified in bloodstream isolates, thus all candidemia cases were by C. albicans. The mass spectrometry, cornmeal agar, Niger and hypertonic broth agreed with genotypic test. The isolates exhibited more susceptibility to anidulafungin, and 90% of them (MIC90) exhibited the lowest values against amphotericin B. Based on ECV and Pfaller classification, isolates could be resistant to fluconazole, demonstrating the importance of the combination of these parameters.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-08-16T14:12:02Z No. of bitstreams: 1 2017 - Gerhard Valkinir Cabreira.pdf: 1076645 bytes, checksum: 61bdbca123cd46ef5ee16794ef55fd17 (MD5) / Made available in DSpace on 2018-08-16T14:12:02Z (GMT). No. of bitstreams: 1 2017 - Gerhard Valkinir Cabreira.pdf: 1076645 bytes, checksum: 61bdbca123cd46ef5ee16794ef55fd17 (MD5) Previous issue date: 2017-02-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / One of the ways to promote forest restoration is through the planting of shrub and tree species for the formation of forest stands. For this, it is necessary to obtain quality seedlings, as it will provide greater capacity to withstand the adverse conditions found in the field; and this quality is closely related to the choice of container type and substrate. Among the products with potential of use as substrate for the production of the forest seedlings is the stabilized sewage sludge (biosolid). A solid waste from Sewage Treatment Plants, rich in organic matter and nutrients, which allows an increase in nursery production, cost reduction and an adequate form of solid waste recycling. In this context, the first part of this study had the objective of evaluating the growth of seedlings of three forest species produced in tubes of 110 and 280 cm3, with increasing doses of controlled release fertilizer applied to biosolids as substrate base. Also, the survival and initial growth of these seedlings after planting were evaluated. In this analysis, the results showed that the seedlings of the three species responded positively to the addition of controlled release fertilizer to the biosolids. Field planting showed good survival and seedling growth, indicating that it was better to produce seedlings of the three species in 280 cm3 tubes with 3 kg of controlled release fertilizer N-P-K (15-09-12) per m3 of biosolids, applied at the time of filling of the tubes. From the results of the biosolids in the nursery, the objective was to evaluate the use of biosolids as fertilizer in field conditions, comparing them to the use of mineral fertilization, using two forest species with controlled growth and response. In the first months after planting, there was basically no significant difference between the use of biosolids and mineral fertilization / Uma das maneiras de impulsionar a restaura??o florestal ? com o plantio de esp?cies arbustivas e arb?reas para a forma??o dos povoamentos florestais. Para isso, faz-se necess?rio a obten??o de mudas de qualidade, pois ir? proporcionar maior capacidade de resistirem ?s condi??es adversas encontradas no campo; e essa qualidade est? intimamente relacionada ? escolha do tipo de recipiente e do substrato. Dentre os produtos com potencial de uso como substrato para produ??o das mudas florestais tem-se o lodo de esgoto estabilizado (bioss?lido). Um res?duo s?lido oriundo das Esta??es de Tratamento de Esgoto (ETEs), rico em mat?ria org?nica e nutrientes e que possibilita aumento na produ??o dos viveiros, diminui??o de custos, al?m de constituir uma forma adequada de reciclagem de res?duos s?lidos. Nesse contexto, a primeira parte desse estudo teve por objetivo avaliar o crescimento de mudas de tr?s esp?cies florestais produzidas em tubetes de 110 e de 280 cm3, com doses crescentes de fertilizante de libera??o controlada N-P-K (15-09-12) aplicados ao bioss?lido como substrato base. Tamb?m, foi avaliado a sobreviv?ncia e crescimento inicial destas mudas ap?s plantio. Nessa an?lise, os resultados mostraram que as mudas das tr?s esp?cies responderam positivamente ao acr?scimo de fertilizante de libera??o controlada junto ao bioss?lido. O plantio em campo apresentou boa sobreviv?ncia e crescimento das mudas, indicando ser melhor produzir mudas das tr?s esp?cies, em tubetes de 280 cm3 com 3 kg de fetilizante de libera??o controla N-P-K (15-09-12) por m3 de bioss?lido, aplicados na ?poca de enchimento dos tubetes. A partir dos resultados que o bioss?lido apresentava no viveiro, buscou-se avaliar o uso do bioss?lido como aduba??o de plantio em condi??es de campo, comparando ao uso de fertiliza??o mineral, utilizando duas esp?cies florestais de crescimento e resposta controlada. Nos primeiros meses ap?s o plantio, basicamente n?o houve diferen?a significativa entre o uso de bioss?lido e fertiliza??o mineral

Nesta tese de doutorado é utilizada a técnica híbrida analítico-numérica, conhecida internacionalmente por GITT (Generalized Integral Transform Technique), para modelagem e simulação da equação de conservação das espécies químicas, na investigação do escoamento laminar incompressível, newtoniano e permanente em tubos permeáveis. O escoamento é aplicado ao processo de filtração tangencial com membranas e foram realizados dois estudos relacionados à equação convectiva-difusiva elíptica e parabólica, para as quais são utilizadas as mesmas condições de fronteira. Na modelagem a velocidade na parede permeável é considerada uniforme e os perfis de velocidade para a região de entrada do escoamento são obtidos na literatura. O modelo matemático utiliza originalmente uma expressão para a espessura da camada limite de concentração, com uma metodologia que determina a taxa assintótica, com a qual se estabelece a espessura da camada de concentração. Os resultados são apresentados com análise de convergência através de tabelas e com gráficos para o fluxo transmembrana local e médio, a correlação de Sherwood e a espessura da camada limite de concentração e ainda são comparados com outros resultados e metodologias reportadas na literatura. / In this doctoral thesis, the analytical-numerical hybrid technique, internationally known as GITT (Generalized Integral Transform Technique), is used for the modeling and simulation of the equation of chemical species conservation, in the investigation of the incompressible, Newtonian and permanent laminar flow in permeable tubes. The flow is applied to the cross-flow process with membranes and two studies related to the elliptic and parabolic convective-diffusive equation were accomplished, for which the same boundary conditions are used. In the modeling, the velocity on the permeable wall is considered uniform and the velocity profiles for the entrance region flow are obtained from the literature. The mathematical model originally uses an expression for the concentration boundary layer thickness, with a methodology that determines the asymptotic ratio, establishing the concentration boundary layer thickness. The results are presented with convergence analysis through tables and with graphs for the mean local transmembrane flux, Sherwood correlation and the concentration boundary layer thickness, and they are also compared with other results and methodologies reported in the literature.

No presente trabalho foi analisado o comportamento de ligações viga-pilar em estruturas mistas de aço e concreto com o auxílio de simulação numérica e experimentação. A simulação numérica foi realizada no programa DIANA, baseado no método dos Elementos Finitos. Os modelos de ligações analisados são compostos por ligações com parafusos passantes entre pilares metálicos preenchidos com concreto e vigas metálicas. A laje utilizada foi do tipo com fôrma de aço incorporada, com a utilização de conectores de cisalhamento para resistir aos esforços em conjunto com a viga. Para simular a situação de pilar intermediário, foram utilizados modelos com formato cruciforme, os quais foram submetidos à força cíclica reversível com a finalidade de submeter à estrutura a esforços semelhantes aos provocados por vento e sismo. Além do efeito da força cíclica, este trabalho avaliou também a influência na rigidez da ligação causada pela taxa de armadura da laje e pelo detalhe de ancoragem da armadura de continuidade ao pilar misto. Para isso foram ensaiados quatro modelos. Dentro da metodologia proposta, obteve-se numérica e experimentalmente, dados que permitiram a construção de curvas momento versus rotação e força versus deslocamento para a quantificação da rigidez e determinação da ductilidade da ligação. Como resultado das análises concluiu-se que a laje contribui mais na rigidez da ligação quando ela está submetida a momento fletor positivo e com relação ao método de ancoragem não houve diferença significativa nas rigidezes. / This research studied the behavior of beam-column connection in composite steel-concrete structures and was developed with the use of numerical simulation and experimentation. The numerical simulation was performed using the program DIANA which is based on the finite element method. The models are composed of connections with bolts passing through the concrete filled tube (CFT) column and steel beams with a steel deck. It was used shear connectors for the slab works together with the beam to resist the bend. To simulate the situation of the middle column, they are used models with cruciform form, which were subjected to reversible cyclic loading in order to bring structure the efforts similar to those caused by wind and earthquake. Besides the effect of cyclic loading, this research also evaluated the influence on the connection stiffness caused by the slab reinforcement ratio and anchors detail to the column of some bars. To obtain this information four models were tested. Within the proposed methodology numerical and experimental data were obtained which made possible the construction of moment versus rotation curves and loading versus displacement for the quantification of stiffness and ductility of the connections. The result of this research shows that the slab contributes more on the increase of stiffness when the connection is subjected to sagging moment and about the method of anchoring, there is no significant difference on stiffness between the two methods.

Orientador: André Luiz Seixlack / Resumo: Evaporadores são trocadores de calor usados em sistemas de refrigeração com a função de transferir calor do ambiente a ser refrigerado. As baixas temperaturas de operação desses trocadores de calor favorecem a formação de geada sobre suas superfícies. O acúmulo de geada, dependendo de sua espessura, pode reduzir a capacidade de refrigeração do evaporador e, consequentemente, reduzir também o desempenho do sistema de refrigeração. Neste trabalho apresenta-se um modelo distribuído para analisar a influência da formação e do adensamento de geada sobre o desempenho de evaporadores do tipo tubo-aletado, comumente usados em refrigeradores frost-free. O escoamento do fluido refrigerante no interior dos tubos é considerado unidimensional e dividido em duas regiões: uma de escoamento bifásico e outra de vapor superaquecido. A queda de pressão do escoamento no interior dos tubos é considerada. As equações fundamentais de conservação da massa, da quantidade de movimento e de conservação de energia são usadas para modelar o escoamento do fluido refrigerante. Na região bifásica o escoamento é analisado segundo o modelo homogêneo. A equação da conservação da energia na parede do tubo também é resolvida, para o cálculo da distribuição de temperatura ao longo dessa parede. Do lado do ar, os princípios de conservação da massa, quantidade de movimento e de conservação da energia são empregados para simular a formação e crescimento da geada sobre a superfície do evaporador. O sistema de equaçõe... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Evaporators are heat exchangers of the refrigeration systems used to transfer heat from the refrigerated environment. Their low operating temperatures favour the frost formation on their surfaces. Frost accumulation, depending on its thickness, can reduce the evaporator cooling capacity and, consequently, also reduce the refrigeration system performance. This work presents a distributed model to analyze the influence of formation and frost densification on the performance of tube-finned evaporators, commonly used in “no-frost” household refrigerators. The refrigerant flow inside the tubes is taken as one-dimensional and divided in a two-phase flow region and a superheated vapor flow region. The pressure drop inside the tubes is considered. The fundamental equations of mass conservation, momentum, and energy conservation are used in order to model the refrigerant flow. The homogeneous flow model is employed for the two-phase flow region. The energy conservation equation for the evaporator tube wall is also solved to obtain of wall temperature distribution. On the air side, the principles of mass conservation, momentum and conservation of energy are employed to simulate the formation and frost growth on the evaporator surface. The system of equations is integrated numerically and solved iteratively by successive substitutions. Comparisons between numerical results obtained in this work and experiments available in open literature show good agreement. Considering the entire rang... (Complete abstract click electronic access below) / Mestre

Molybdenum experiments: In Australia young Merlot vines sometimes suffer from vegetative disorders such as slow, zigzagged growth and leaf distortion. Merlot is also particularly known as a low- and inconsistent-yielding grape variety. Previous research showed that when foliar applications of molybdenum (Mo) were applied to Merlot vines the vegetative symptoms improved. More recently, when sodium molybdate was applied to Mo-deficient Merlot, yield improved; a function of increased bunch weight brought about by bigger berries. It has also been reported that at high concentrations, molybdenum might be detrimental to yield. Experiments were conducted on own-rooted Merlot (clone D3V14) vines in commercial vineyards in the Adelaide Hills (Hills) and at McLaren Vale, South Australia. Effects of molybdenum deficiency on the vegetative growth and yield of Vitis vinifera cv. Merlot: The aims of the current study were to: a) elucidate the mechanism by which molybdenum affects yield of Merlot; b) to monitor the effects of Mo-treatment on the balance between vine reproductive and vegetative growth; c) to monitor the residual effects of Mo-treatment on growth and yield of Merlot and; d) to determine whether high concentrations of molybdenum are detrimental to yield. Three rates of sodium molybdate were applied to vines in springtime (control = 0g, rate 1 = 0.101g and rate 2 = 0.202g sodium molybdate per vine). Vine molybdenum status was measured prior to treatment and again at flowering time using petiole, shoot tip and inflorescence analysis. The effects on vegetative growth were monitored at veraison, during dormancy and at budburst in the seasons following Mo-treatment. At flowering time, pollen vitality, pollen tube growth and flower structure were examined. Bunch number per vine, fruitset, berry weight and berry composition were measured at harvest. In the Hills, the controls had adequate molybdenum however, at McLaren Vale petiolar molybdenum concentration fell within the suggested deficiency range of 0.05-0.09 mg/kg in the petioles at flowering time. No visual symptoms of Mo-deficiency were observed on the experimental vines. At McLaren Vale, Mo-treatment reduced pruning weight and improved vine balance. Mo-treated vines in the Hills and at McLaren Vale were affected by delayed budburst in the season following Mo-treatment irrespective of their Mo-status. However, no seasonal carryover of molybdenum could be detected in tissue analysis at flowering time. Juice total soluble solids, pH and titratable acidity were not affected by Mo-treatment at McLaren Vale or in the Hills. However, juice from Mo-treated vines in the Hills had a significantly higher concentration of molybdenum than the controls. At McLaren Vale there was no significant difference in juice molybdenum concentration between treatments. In the Hills, yield was not affected by Mo-treatment. However, Mo-treated vines at McLaren Vale had significantly higher yields (approximately double) than the Mo-deficient controls. Bunch number per vine was not affected by Mo-treatment, either in the year that treatments were applied or in the following season. However, bunches from Mo-treated vines had significantly better fruitset resulting in more berries per bunch. Berry weight was affected by Mo-treatment in one season only. Yield was not detrimentally affected on vines that received the higher rate of sodium molybdate. In the Hills, Mo-treatment did not affect pollen numbers, pollen vitality or pollen tube growth. At McLaren Vale, where the controls were Mo-deficient, pollen vitality was not affected by Mo-treatment. However, pollen tube growth was significantly enhanced by Mo-treatment. Significantly more pollen tubes penetrated the ovules from Mo-treated vines and a higher proportion of ovaries had at least one penetrated ovule. Structural observations revealed that a significantly higher proportion of ovules from Mo-deficient vines were defective. The absence of an embryo sac in those ovules is probably the cause of pollen tube growth inhibition and subsequent poor fruitset. Effects of mode of pollination on yield of Merlot and the interacting effects of sodium molybdate sprays: Pollination experiments were conducted on field-grown own-rooted Merlot (clone D3V14) vines in commercial vineyards in the Adelaide Hills and at McLaren Vale in 2003-04 and in 2004-05. Inflorescences were supplied with supplementary Merlot pollen (self-pollination), with pollen from another variety (cross-pollination) or they were left to pollinate naturally (open pollination). In the Hills, mode of pollination did not affect fruitset or berry weight. In 2003-04 fruitset increased significantly at McLaren Vale when inflorescences were cross-pollinated with Semillon. Applying supplementary Merlot pollen also tended to improve fruitset, however none of the treatments affected berry weight. In 2004-05 there was no significant difference between treatments. These results indicate that Merlot may be a poor producer of pollen and may suffer from self-incompatibility. Given the significant improvements in yield gained by spring foliar applications of sodium molybdate to Mo-deficient Merlot vines, in 2005-06 a reciprocal experiment was conducted to separate the effects of Mo-treatment and mode of pollination on the male and female flower parts. The aims of this experiment were to: a) determine whether the male or female reproductive organs are more important in determining the success of fruitset of Merlot and; b) determine which remedial measure, Mo-treatment or pollination, is more effective at overcoming poor fruitset. Supplementary pollination treatments—cross-pollination (Semillon); self-pollination (Mo-deficient pollen); self-pollination (Mo-treated pollen) and; open-pollination—were applied to Mo-treated and Mo-deficient vines. Cross-pollinating Mo-deficient vines with Semillon significantly improved fruitset of Merlot compared to other pollination treatments on those vines, however applying molybdenum to the vines in springtime was more effective at improving fruitset. Within the Mo-treated vines the effects of supplementary pollination on fruitset were not thought to be of any practical significance. The results of this experiment provide further evidence that Mo-deficiency affects the female flower parts more than the male reproductive organs of Merlot. The occurrence of ‘star’ flowers in Australia: In 2003 faulty flowers were discovered on Canada Muscat grown in the Coombe Vineyard at the University of Adelaide’s Waite Campus. The Canada Muscat flowers opened from the top in ‘star’ formation in contrast to normal grape flowers, which shed the calyptra from its base. Star flowers were reported in French literature in the late 1800s. They were reported to as a symptom of a ‘disease’ that caused ‘coulure’, the cure for which was vine removal. The current report is the first known report of star flowers occurring in Australia. Through dissemination of the news of this discovery, several star flower variants were found in other varieties in South Australia. The association of star flowers with poor berry development and the frequency of the occurrence of star flowers suggest that this flower aberration may be affecting yield to a greater extent than previously recognised. This study provides a detailed description of two types of star flowers: those that occur in response to environmental conditions and those that occur every season. Other star flower variants are also documented. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1280856 / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2007