Thesis (doctoral)--Swedish University of Agricultural Sciences, 2000. / Includes bibliographical references.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-05-23T17:22:03Z No. of bitstreams: 1 texto completo.pdf: 4532924 bytes, checksum: 61bc2de7afcba6cd895b12131462556b (MD5) / Made available in DSpace on 2016-05-23T17:22:03Z (GMT). No. of bitstreams: 1 texto completo.pdf: 4532924 bytes, checksum: 61bc2de7afcba6cd895b12131462556b (MD5) Previous issue date: 2000-08-31 / Fundação de Amparo à Pesquisa do Estado de Minas Gerais / O sistema de confinamento tipo baias livres possibilita produzir leite em escala industrial, objetivando queda no custo do produto primário, aliado à alta qualidade e à eficiência do processamento. A execução de projetos para confinamento de gado de leite depende do conhecimento prévio das atividades desenvolvidas e das inter-relações entre os fatores que compõem o processo produtivo. A análise dos fatores envolvidos no processo de produção permite a modernização e a otimização do sistema produtivo, por meio do arranjo de áreas de trabalho, analisando os espaços, o que leva à racionalização e à simplificação das instalações. O estudo do posicionamento dos recursos produtivos, antes de sua implantação, agrega valor ao empreendimento, permitindo que todas as modificações se integrem segundo um programa global e coerente. Para isso, nesta pesquisa foi usado, como referencial de procedimento sistematizado para o arranjo físico de áreas de produção, o método SLP - Systematic Layout Planning, o qual consiste em uma estruturação de fases onde as diversas unidades, áreas ou atividades funcionais são combinadas a um grande número de considerações, objetivos, fatores e elementos a serem alcançados. A pesquisa objetivou adaptar uma metodologia que permita orientar o estudo e o planejamento de sistemas intensivos de produção de leite em confinamento tipo baias livres para diferentes realidades espaciais das propriedades. Foi realizado um diagnóstico da situação deste sistema de produção em unidades produtoras de algumas regiões leiteiras do Estado de Minas Gerais, investigando-se os principais fluxos e suas relações espaciais com os diversos setores. A coleta de dados foi realizada nos meses de janeiro e fevereiro de 2000, sob condições climáticas de verão, em quatro unidades de produção de leite que utilizam o sistema intensivo com estabulação livre, em regime comercial de exploração. As análises foram consolidadas em um modelo geográfico que mostra as instalações necessárias, a seqüência de atividades e os respectivos graus de proximidades; das análises resultou um esboço de localização no qual instalações, atividades e proximidades são rearranjadas de acordo com os requisitos de espaço, estabelecidos por meio da comparação das áreas existentes nas instalações das fazendas e da bibliografia levantadas, considerando-se a relação metro quadrado e metro cúbico por animal estabulado. Com base na área apropriada para cada atividade, considerando-se a melhor relação geográfica e o grau de proximidade entre elas, a pesquisa se completou com a apresentação de uma proposta piloto de arranjo físico, que pode servir de referência para a implantação de sistemas de confinamento tipo baias livres. / The confinement system of the free stall type enable production of milk in industrial scale, with the purpose of lowering the cost of the primary product, allied with high quality and processing efficiency. The execution of projects for the confinement of milk cows depends on prior knowledge of the developed activities and of the inter-relations factors that makes up the productive process. The analysis of the factors involved in the production process makes possible the modernization and optimization of the productive system, through the outlining of work areas, analyzing the available space, which leads to the rationalization and simplification of the installations. The study of the positioning of the productive resources, before implementation, adds value to the enterprise, allowing that all modifications integrate according to a global and coherent program. The SLP - Systematic Layout Planning-method consists of phase structuring, where the several units, areas or functional activities are combined with a large number of considerations, objectives, factors, and elements to be met, being used in this investigation as a reference of a systematized procedure for the physical arrangement of production areas. The study had as a purpose to adapt a methodology that guides the study and the planning of intensive systems of milk production in confinement of the free stall type for different space realities of the farms. A diagnostic study was carried out regarding the situation of the productive system in some milk production regions in the state of Minas Gerais, investigating the main flows and their spatial relations with several sectors. The gathering of data was carried out during the months of January and February of 2000, under summer climatic conditions, in four milk production units that use the intensive, free stall, system, in a commercial regimen of exploitation. The analysis were united in a geographic model that exhibits the necessary installations, the sequence of activities and the degree of proximity of the farms in an location outline where rearrangement are made according to space requirements, established through a comparison of the existing areas of installations on the farms and the data obtained through the search of the literature, considering the relation m2 and m3 per stabled animal. Based on the appropriate area for each activity, considering the best geographic relation and the degree of proximity, this investigation results in a proposal of a pilot pre- project, that might serve as a reference for the implementation of confinement systems of the free stall type.

Le présent travail s'inscrit dans le cadre d'une convention CIFRE entre Liebherr-Aerospace Toulouse SAS et le Département d'Aérodynamique Energétique et Propulsion (DAEP) de l'ISAE. L’étude porte sur l'analyse des mécanismes responsables de la perte de la stabilité d'un étage de compression centrifuge. L'objectif industriel sous-jacent est l'élargissement de la plage de fonctionnement stable des compresseurs. Les travaux sont abordés par voie numérique à l'aide du code de calcul elsA, développé par l'ONERA et le CERFACS. Les simulations instationnaires sont effectuées sur la circonférence complète des roues.La topologie de l'écoulement est analysée dans un premier temps selon trois points de fonctionnement stables répartis sur la courbe caractéristique de l'iso-vitesse de design. Cette analyse permet de décrire l'évolution des phénomènes lorsque le débit est réduit. Au voisinage de la ligne de stabilité, l'excès d'incidence sur les aubes du rouet déclenche le décollement de la couche limite sur la face en d’expression. Le guide issu de la zone décollée migre en direction du carter et alimente l'écoulement de jeu. En conséquence, le déficit de vitesse au voisinage du carter s'intensifie et un lâcher périodique de structures tourbillonnaires apparaît à l'interface entre les écoulements secondaires et l'écoulement principal.La perte de la stabilité de l'étage s’établit suite à la naissance d'une perturbation de type « modal » au sein de l'espace lisse. Cette dernière induit de fortes distorsions circonférentielles dans l'étage de compression mais affecte plus particulièrement l'écoulement à l'entrée du rouet. Sur la moitié de la circonférence, l'interface entre les écoulements secondaires et l'écoulement principal ainsi que les structures tourbillonnaires sont déplacées en amont du front de grille. Le taux total-total du rouet chute de manière brutale et entraîne la perte de la stabilité de l'étage.Enfin, la dernière partie de ce travail est dédiée à la mise en place de critères adaptés au modèle stationnaire mono-canal utilisé chez LTS. Ces critères seront utilisés pour améliorer la prédiction de la ligne de pompage en phase de design. Dans un premier temps, la pertinence de l'utilisation du modèle stationnaire au voisinage de la ligne de stabilité est évaluée. Dans un second temps, les influences de la vitesse de rotation et de la géométrie de l’étage sur la topologie sont étudiées.Deux situations sont jugées critiques vis-à-vis de la stabilité. La première concerne l'alignement de l'interface entre l'écoulement de jeu et l'écoulement principal avec le front de grille. La deuxième concerne l'opération du compresseur avec un angle d'écoulement en sur-incidence sur les aubes du diffuseur qui s'établit sur toute la hauteur de veine. / This work results from a CIFRE partnership between Liebherr-Aerospace Toulouse SAS and the Aerodynamics, Energetics and Propulsion Department (DAEP) of ISAE. The main objective is to investigate the mechanisms responsible of the stall onset in a centrifugal compressor operating at the nominal rotational speed. It is part of a larger work which aims at extending the stable operating range of compressors integrated in air conditioning system. The analyses are based on the results of unsteady simulations, in a calculation domain comprising all the blade passages. They are performed with the elsA software developed by ONERA and CERFACS.The investigations show the modifications of the unsteady flow pattern when the mass flow is reduced along the speed line. Near the stability limit, the high incidence angle on the impeller blade leads to a boundary layer separation on the suction side. The fluid in the separation zone moves toward the shroud and enlarges the low momentum flow zone generated by the leakage flow. The interface between the leakage flow and the main flow becomes unstable to the extent of a periodic vortex formation.The path to instability is driven by the growth of a small amplitude disturbance (modal wave) rotating in the vaneless space. The length scale of the wave is equal to the compressor circumference. This perturbation induces distortions and alters the flow characteristics in every location of this subsonic stage, and more specifically the impeller inlet flow structure: the unstable interface between the main flow and the leakage flow is periodically moved upstream of the leading edge plane causing a significant drop of the impeller total-to-total pressure ratio. The last part of this work concerns the definition of criteria which can improve the surge line prediction during the design process in an industrial environment. Therefore, they are adapted to the numerical steady model using the mixing plane approach. To do so, the capacity of the steady model to predict the flow structure when the compressor operates near stall is investigated. Then, the effects of the rotational speed and of the compressor geometry are evaluated. Theses two steps have permitted to define two critical situations regarding the stage stability. The first one is related to the alignment of the interface between the main flow and the leakage flow with the leading edge plane. The second one concerns the compressor operation with positive incidence on the diffuser vane, along the full span.

abstract: The effect of reduced frequency on dynamic stall behavior of a pitching NACA0012 airfoil in a turbulent wake using Direct Numerical Simulations is presented in the current study. Upstream turbulence with dynamically oscillating blades and airfoils is associated with ambient flow unsteadiness and is encountered in many operating conditions. Wake turbulence, a more realistic scenario for airfoils in operation, is generated using a small solid cylinder placed upstream, the vortices shed from which interact with the pitching airfoil affecting dynamic stall behavior. A recently developed moving overlapping grid approach is used using a high-order Spectral Element Method (SEM) for spatial discretization combined with a dynamic time-stepping procedure allowing for up to third order temporal discretization. Two cases of reduced frequency (k = 0:16 and 0:25) for airfoil oscillation are investigated and the change in dynamic stall behavior with change in reduced frequency is studied and documented using flow-fields and aerodynamic coefficients (Drag, Lift and Pitching Moment) with a focus on understanding vortex system dynamics (including formation of secondary vortices) for different reduced frequencies and it’s affect on airfoil aerodynamic characteristics and fatigue life. Transition of the flow over the surface of an airfoil for both undisturbed and disturbed flow cases will also be discussed using Pressure coefficient and Skin Friction coefficient data for a given cycle combined with a wavelet analysis using Morse wavelets in MATLAB. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2017

Made available in DSpace on 2015-03-26T13:54:43Z (GMT). No. of bitstreams: 1 texto completo.pdf: 217799 bytes, checksum: dc5b6c16d985e080faefdc7202d7fbd8 (MD5) Previous issue date: 2009-02-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / It was evaluated the effect of diets with levels crude protein - CP (10, 12, 14 and 16% in dry matter - DM) on the performance and efficiency of utilization of nutrients in dairy cows. Twelve Holstein cows with average body weight (BW) of 570 kg, milk production (MP) of 13 kg/day were distributed in three 4x4 Latin squares. The feed consisted of 75% of corn silage and 25% of concentrate. Increased (P <0.05) linear in the intake of all components of the diet, except for total carbohydrates and non- fibrous carbohydrates (NFC), which decreased (P <0.05) linearly with the increase CP in the diet. The intake of total digestible nutrients (TDN) presented quadratic effect (P <0.05) with increase of CP, and estimated the maximum value of 10.13 kg / day at level of 15.62% of CP in the diet. The digestibility of CP, ether extract, neutral detergent fiber without and corrected for ash and protein increased (P <0.05) linearly with increases of CP. But the values for digestibility of dry matter, organic matter, NFC and TDN showed quadratic effect (P <0.05) with increases of CP, with an estimated point of maximum of 65.09, 67.23, 78.35 and 67.92 at leves of 15.39, 15.22, 12.62 and 15.68% CP, respectively. The MP, without and with correction to 3.5% fat (MPC), body weight variation and composition of the milk increased linearly (P <0.05) as function of the leves of CP, except for lactose which had no effect. The efficiency of nitrogen compounds in milk (kg milk N/kg N intake) presented quadratic effect (P <0.05) estimated the minimum value of 0.21 at the level of 15.57% CP. The excretions of purine derivatives in urine and protein production, urine volume and concentration of urea in milk and blood plasma increased (P <0.05) linearly with increase the CP. However, the excretion of urea nitrogen in urine showed a quadratic effect (P <0.05), estimated minimum value of 16.27 at the level of 9.08% CP. The balance of nitrogen increased (P <0.05) linearly with the level of CP, BN is estimated to be zero in the level of 11.59% CP. The level of 14% CP in the diet is more suitable for feeding to cows with average production of 13kg/dia milk. / Avaliou-se o efeito de dietas com níveis de proteína bruta - PB (10, 12, 14 e 16% na matéria seca - MS) sobre o desempenho produtivo e eficiência de utilização dos nutrientes em vacas em lactação. Doze vacas da raça Holandesas com peso corporal (PC) médio de 570 kg, produção de leite (PL) de 13 kg/dia foram distribuídas em três quadrados latinos (4x4). O volumoso utilizado foi a silagem de milho e a relação volumoso:concentrado foi de 75:25. Houve aumento (P<0,05) linear para o consumo de todos os componentes da dieta, exceto para o consumo de carboidratos totais e carboidratos não fibrosos, que reduziram (P<0,05) linearmente com os acréscimos de PB na dieta. O consumo dos nutrientes digestíveis totais (NDT) apresentou comportamento quadrático (P<0,05) ao aumento da PB, sendo estimado o valor máximo de 10,13 kg/dia na dose de 15,62% de PB na dieta. As digestibilidades da PB, extrato etéreo, fibra em detergente neutro sem e corrigido para cinzas e proteína aumentaram (P<0,05) linearmente com os acréscimos de PB. Já os valores de digestibilidade da matéria seca, matéria orgânica, CNF e NDT apresentaram efeito quadrático (P<0,05) com os acréscimos de PB, estimando-se ponto de máximo de 65,09, 67,23, 78,35 e 67,92 nas doses de 15,39, 15,22, 12,62 e 15,68% de PB, respectivamente. A PL, sem e com correção para 3,5% de gordura (PLG), a variação de peso corporal e a composição do leite aumentaram linearmente (P<0,05) em função dos aumentos de PB, exceto para lactose que não apresentou efeito. A eficiência de utilização de compostos nitrogenados no leite (kg de N no leite/kg de N ingerido), apresentou efeito quadrático (P<0,05) estimando o valor mínimo de 0,21 no nível de 15,57% de PB. As excreções de derivados de purina na urina e produção de proteína microbiana, volume urinário e concentração de uréia no leite e no plasma sanguíneo aumentaram (P<0,05) linearmente com os aumentos de PB. No entanto, a excreção de nitrogênio uréico na urina apresentou efeito quadrático (P<0,05), estimando valor mínimo de 16,27 g/dia no nível 9,08% de PB. O balanço de nitrogênio aumentou (P<0,05) linearmente com o nível de PB, estimando-se BN nulo no nível de 11,59% de PB. O nível de 14% de PB na dieta é o mais indicado para alimentação de vacas com produção média de 13kg/dia de leite.

Submitted by Helena Bejio (helena.bejio@unioeste.br) on 2018-03-29T00:14:40Z No. of bitstreams: 2 Dieisson Gregory Grunevald.pdf: 1350221 bytes, checksum: 3dfd65d062ab1e1ef33afed0676f7980 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-03-29T00:14:40Z (GMT). No. of bitstreams: 2 Dieisson Gregory Grunevald.pdf: 1350221 bytes, checksum: 3dfd65d062ab1e1ef33afed0676f7980 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present study was subdivided into two trials. The first test had as objective to evaluate by means of indices of thermal comfort two distinct environments (free stall and picket) from 07:00 to 16:00 hours considering the sunny, partly cloudy and cloudy sky. The second objective was to evaluate the physiological parameters of Dutch heifers allocated to pickets with full sun exposure and free stall for two hours from 11:00, 12:00, 13:00 and 14:00 hours on non-consecutive days also considering the three types of sky coverage. The tests were carried out in the municipality of Marechal Cândido Rondon - PR, in the months of July and August of 2016. For the evaluation of the physiological parameters, nine heifers of the black and white Dutch breed were used, with mean age of 20 ± 3.5 months and mean body mass of 490 ± 64.12 kg and on average in the 5th month of pregnancy. The experimental design was completely randomized with time-repeated measures. The physiological variables evaluated were: Respiratory rate (RR), heart rate (HR), rectal temperature (RT) and surface temperature (ST). The data on air temperature, black globe temperature, relative humidity and wind speed were collected and used to determine the temperature and humidity index (THI), black globe humidity index (BGTI) and radiant heat load (RHL). In this study, it was verified that the free stall presented a more adequate thermal environment, especially when associated with cloud cover, presenting THI = 62, BGTI = 64 and RHL = 412 W m -2 when compared to full sun conditions with THI = 76, BGTI = 83 and RHL = 754 W m-2. The physiological parameters presented variation according to the moment of entry and the time of exposure to shade. However, they remained within normal limits for cattle, in all types of sky cover. The body surface temperature was the only physiological parameter that presented a strong positive correlation (r > 0.5) with THI, BGTI and RHL. The body surface temperature in dark fur areas of the animal was significantly higher (< 0.05) than that observed in light coat areas. There was no significant interaction for the time of entry and the dwell time in the shade between the types of sky cover, for none of the physiological parameters (HR, RR, ST and RT) evaluated. In this way, it can be concluded that although the thermal environment was characterized as critical, as shown in the thermal comfort indices, there were no significant alterations in the physiological parameters of the animals in the picket under a sunny condition in the afternoon. / O presente estudo foi subdividido em dois ensaios. O primeiro ensaio teve como objetivo avaliar por meio de índices de conforto térmico dois ambientes distintos (free stall e piquete) das 07:00 às 16:00 horas considerando a cobertura de céu ensolarado, parcialmente nublado e nublado. O segundo ensaio teve como objetivo avaliar parâmetros fisiológicos de novilhas da raça holandês alocados em piquetes com exposição a pleno sol e com disponibilidade de sombra (Free stall) por duas horas a partir das 11:00, 12:00, 13:00 e 14:00 horas em dias não consecutivos também considerando os três tipos de cobertura de céu. Os ensaios foram realizados no município de Marechal Cândido Rondon – PR, nos meses de julho e agosto de 2016. Para a avaliação dos parâmetros fisiológicos foram utilizadas nove novilhas da raça holandês preta e branca, com idade média de 20 ± 3,5 meses e massa corporal média de 490 ± 64,12 kg e em média no 5° mês de prenhes. O delineamento experimental utilizado foi inteiramente casualizado com medidas repetidas no tempo. As variáveis fisiológicas avaliadas foram: Frequência respiratória (FR), frequência cardíaca (FC), temperatura retal (TR) e temperatura de superfície (TS). Os dados de temperatura do ar, temperatura de globo negro, umidade relativa e velocidade do vento foram coletados e utilizados para a determinação do Índice de Temperatura e Umidade (ITU), Índice de Temperatura de Globo e Umidade (ITGU) e Carga Térmica de Radiação (CTR). Neste estudo, verificou-se que o free stall apresentou ambiente térmico mais adequado, especialmente quando associado a cobertura de céu do tipo nublado, apresentando ITU = 62, ITGU = 64 e CTR = 412 W m-2 quando comparado a condição a pleno sol com ITU = 76, ITGU = 83 e CTR = 754 W m-2. Os parâmetros fisiológicos apresentaram variação de acordo com o momento de entrada e o tempo de exposição à sombra. No entanto, permaneceram dentro dos limites normais para bovinos, em todos os tipos de cobertura do céu. A temperatura de superfície corporal foi o único parâmetro fisiológico que apresentou forte correlação positiva (r > 0,5) com ITU, ITGU e CTR. A temperatura de superfície corporal em áreas de pelagem escura do animal foi significativamente maior (< 0,05) que a observada nas áreas de pelagem clara. Não houve interação significativa para o momento de entrada e o tempo de permanência à sombra entre os tipos de cobertura do céu, para nenhum dos parâmetros fisiológicos (FC, FR, TS e TR) avaliados. Desta forma, se pode concluir que embora no piquete sob condição ensolarada, no período da tarde, o ambiente térmico foi caracterizado como crítico, como mostram os índices de conforto térmico, não houve alteração significativa nos parâmetros fisiológicos dos animais.

While conventional turbines have been extensively researched and tested, Tesla and boundary layer type turbines have not. In order to construct a dynamometer, thermodynamic flow apparatus and future turbines, we modeled the Tesla turbine using theoretical calculations and preliminary experiments. Thus a series of experiments were run to determine stall torque and maximum run speed for a known pressure range. This data was then applied to modeling formulas to estimate stall torque over an extended range of variables. The data were then used to design an appropriate dynamometer and airflow experiment. The model data also served to estimate various specifications and power output of the future turbine. An Obi Laser SSTG&#8208;001 Tesla turbine was used in the experiments described. Experimental stall torque measurements were conducted in two stages. Shaft speed measurements were taken with an optical laser tachometer and Tesla turbine stall torque was measured using a spring force gauge. Two methods were chosen to model Tesla turbine stall torque: 1) flow over flat plate and 2) free vortex with a sink. A functional dynamometer and thermodynamic apparatus were constructed once the model was confirmed to be within the experimental uncertainty. Results of the experiments show that the experimental turbine at 65 PSI has a speed of approximately 27,000 RPM and a measured stall torque of 0.1279 N&#8208;m. 65 PSI is an important data point because that data set is the cut&#8208;off from laminar to turbulent flow. Thus at 65 PSI, a rejection of the null hypothesis for research question one with respect to the flow over flat plate method can be seen from the data, while the vortex model results in a failure to reject the null hypothesis. In conclusion, the experimental turbine was seen to have a laminar and a turbulent flow regime at different air pressures, rather than the assumed laminar flow regime. As a result of this model work, a new Tesla turbine of different dimensions was designed to adjust for flaws in the experimental turbine. The theoretical stall torque models were then applied to the new Tesla turbine design. Results of the models show that the vortex model sets the upper bound for theoretical stall torque for the new and the flat plate flow model sets the lower bound.

This document describes the design of the roof structure for the dimensions of the rink. It was designed and evaluated three roofing solutions – steel truss structure, concrete arch with external prestress and prestress truss roof girder with concrete roof panel. One option was selected – prestress truss girder. This variant has been further developed. In the beginning was drafted several proposals geometry respecting the demands on the type of construction. Within the static calculation was created a mathematical model of the structure of the program Scia Engineer. Using this model were obtained values needed for the assessment of individual elements of construction and design assessment as a whole for the ultimate limit state and usability. According to the proposed geometry and opinions parts of the structure was drawing documentation structure as a whole and individual parts of the structure solved in this thesis. The last proposal was visualized structures together with the phases of the construction by program ArchiCAD and rendered by program Artlantis.

No description available.

Se realiza un modelo CFD-3D de un compresor centrífugo. Se determina la configuración numérica adecuada para simular puntos de funcionamiento cercanos a bombeo. Se validan los resultados frente a ensayos experimentales realizados en cámara anecoica. Se analizan los resultados, justificando las características del ruido emitido por el compresor a partir de los patrones de flujo encontrados. En particular, se analiza el flujo en la holgura entre los álabes y la carcasa del compresor y en la parte posterior del rodete. Por último, se analiza la influencia de las geometrías aguas arriba del compresor en el ruido producido por éste. / Navarro García, R. (2014). A numerical approach for predicting flow-induced acoustics at near-stall conditions in an automotive turbocharger compressor [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/44114 / TESIS / Premios Extraordinarios de tesis doctorales