nÃo hà / The greater extent of Cearà State (about 90% of its territory) is supplied by winds of the order of 3.5 to 5m / s. On the same extent of territory lie the settlements of farmers (responsible for producing most of the food consumed in our territory) are located in these same regions and possess not support the industries in developing specific equipment to meet the demand energy of these, since the application of wind turbines for power generation is not appropriate. We could use for this purpose, small generators that mostly have curves also not appropriate to these sites. This paper presents a model for designing blades for wind turbines with a view to use in areas characterized as low wind using camber profile. A mathematical model was developed for the design and modeling of the blades of a rotor starting data of wind speeds characteristic of regions of settlements of farmers, potency and specific characteristics required for the installation site generating dimensional parameters enabling the manufacture of rotor blades . The validation model used academic software for comparative data generated by the model. As a way to refine the model, we propose preparation of prototype scale using the methodology presented dimensional analysis coefficients Pi-terms for this purpose. / Grande extensÃo do Estado do Cearà (cerca de 90% de seu territÃrio) à suprida por ventos com velocidade de 3,5 a 5m/s. Nesta mesma extensÃo do territÃrio, encontram-se os assentamentos de agricultores familiares que sÃo responsÃveis pela produÃÃo da maior parte dos alimentos consumidos em nosso territÃrio. Poder-se-ia utilizar para este fim, aerogeradores comerciais de pequeno porte. PorÃm em sua maioria, possuem curvas caracterÃsticas nÃo adequadas (visto nÃo ser para regiÃes com baixas velocidades de vento). Por nÃo possuirem apoio das indÃstrias no desenvolvimento de equipamentos especÃficos para o atendimento da demanda em energia elÃtrica a estes locais, este trabalho apresenta uma modelagem para projeto de pÃs para aerogeradores com vistas a utilizaÃÃo em regiÃes caracterizadas como baixo vento utilizando perfil cambado. Um modelo matemÃtico foi elaborado para o dimensionamento e modelagem das pÃs de um rotor apartir de dados de velocidades de vento caracterÃsticos das regiÃes de assentamentos de agricultores, potÃncia requerida e caracterÃsticas especificas do local de instalaÃÃo gerando parÃmetros dimensionais que permitam a fabricaÃÃo das pÃs do rotor. A validaÃÃo do modelo utilizou o software FoilSim para comparativo dos dados gerados pelo modelo. Como forma de refinamento do modelo, propÃs-se elaboraÃÃo de protÃtipo em escala com uso da metodologia de anÃlise dimensional apresentando coeficientes Pi-termos para este propÃsito.

Made available in DSpace on 2014-07-29T15:18:18Z (GMT). No. of bitstreams: 1 dis pedro r r adriano geotec - pre text.pdf: 293347 bytes, checksum: 0d38b1697ea8493167fcf7f1b15fd61a (MD5) Previous issue date: 2009-09-29 / The main objective of this research is to investigate a three-dimensional (3D) slope stability analysis technique using the enhanced limit equilibrium method. The other objectives are to evaluate the practical applicability of the 3D analysis method, to interpret the physical significance of 3D stress states to the stability of a slope, and to determine the relationship between two-dimensional and three-dimensional factors of safety. For that, a computer program called SAFE3D was developed. The computer program is used to calculate the three-dimensional factor of safety (FS3D) for pre-established slip surfaces with spherical or ellipsoidal shape. The computer program is based on the two-dimensional analysis method proposed by Kulhawy, combined with an extension of this theory to 3D conditions that is proposed herein. The method developed consists in determining the in-situ stress fields by means of an elastic 3D stress-strain analysis using the finite element method. The 3D stress fields are then used to calculate the normal and shear stresses along any pre-determined slip surface and to determine the value of FS3D. Two slope stability problems widely studied by other researchers were analyzed in order to validate the program SAFE3D. The first problem corresponds to a symmetric cohesive slope and the second problem corresponds to a non-symmetric slope with cohesion and friction. Excellent results were obtained, suggesting that the program SAFE3D is efficient, stable, and robust for the problems studied. The values of FS3D obtained herein are similar to the values presented by other authors using distinct methods of analysis. A parametric study was carried out considering the shape of the slip surface and the shape of the face of the slope, including concave and convex slopes. The results indicate that the values of FS3D are always higher than the two-dimensional factor of safety (FS2D) of the intermediate surface. The value of FS3D decreased for slip surfaces extended across the sliding direction and approached the value of FS2D. It was determined that the Poisson's ratio has an important influence on the FS3D. The value of FS3D increases with the increase of Poisson's ratio. This influence varies with the geometry of the problem and the treatment given to the cinematically inadmissible shear stresses. Finally, a 3D analysis of the historic case of Lodalen is presented. The results indicate that the FS3D at the time of the slide is slightly higher and approaches 1 if the less favorable shear strength parameters determined by previous studies are used. In this case, the values obtained for FS2D are considerably smaller than 1, thereby indicating the potential superiority of the 3D approach. / Esta dissertação tem por objetivo principal investigar uma técnica de análise tridimensional (3D) de estabilidade de taludes pelo método do equilíbrio limite aperfeiçoado. É também objetivo deste trabalho avaliar a aplicabilidade prática do método de análise 3D, interpretar a significância física do estado de tensões 3D na estabilidade de taludes e determinar a relação entre os fatores de segurança bidimensional e tridimensional. Para tal, foi desenvolvido um programa computacional denominado SAFE3D. O programa permite o cálculo do fator de segurança tridimensional (FS3D), considerando superfícies de ruptura pré-estabelecidas, com formato esférico ou elipsoidal. O programa é baseado no método de análise bidimensional proposto por Kulhawy, sendo proposta aqui uma extensão deste método para condições 3D. O método desenvolvido consiste na determinação dos campos de tensões in-situ por meio de análises tensão-deformação 3D elásticas pelo método dos elementos finitos. Os campos de tensões 3D assim determinados são utilizados para o cálculo das tensões normais e cisalhantes ao longo de uma superfície de ruptura qualquer, pré-determinada, e para a determinação do FS3D. Para validar o programa SAFE3D foram feitas análises de dois problemas amplamente estudados por outros pesquisadores, o primeiro correspondendo a um talude simétrico coesivo e o segundo a um talude não-simétrico com coesão e atrito. Foram obtidos excelentes resultados, que sugerem que o programa SAFE3D é eficiente, estável e robusto para os problemas estudados. Os valores de FS3D obtidos são semelhantes àqueles obtidos por outros autores, utilizando métodos distintos. Foram realizadas também baterias de análises paramétricas, considerando o formato da superfície de ruptura e o formato da face do talude, incluindo taludes côncavos e convexos. Os resultados indicam que o FS3D é sempre superior ao fator de segurança bidimensional (FS2D) da superfície intermediária. O valor de FS3D diminuiu para superfícies de ruptura alongadas transversalmente à direção de ruptura, tendendo ao valor de FS2D. Foi determinado que o coeficiente de Poisson possui importante influência no FS3D, sendo que o FS3D cresce com o aumento do coeficiente de Poisson. Tal influência varia de acordo com a geometria do problema e com o tratamento dado às tensões cisalhantes cinematicamente inadmissíveis. Finalmente, é apresentada uma análise 3D do caso histórico de Lodalen. Os resultados obtidos indicam que o FS3D no momento da ruptura é ligeiramente superior e se aproxima de 1, caso sejam utilizados os parâmetros de resistência menos favoráveis, determinados pelos estudos originais. Neste caso, os valores de FS2D são consideravelmente inferiores a 1, indicando a potencial superioridade da abordagem 3D.

A uniformidade de emissão ao longo de uma linha lateral de irrigação localizada em nível, está relacionada com a variação de pressão, ocasionada pela perda de carga durante o escoamento da água no tubo emissor e pela saída de água pelos emissores ao longo da linha lateral. Para calcular o comprimento máximo das linhas laterais, é necessário determinar de forma precisa essa variação de pressão para atender um critério pré-estabelecido de variação de vazão. O objetivo desse trabalho foi desenvolver metodologia para o cálculo da perda de carga em linhas laterais de gotejamento com emissores do tipo bóbi, para tal foram desenvolvidos dois modelos, um usando regressão linear múltipla e outro usando análise dimensional. Ambos tiveram como base equações de perdas de carga contínua no tubo e localizadas nos emissores disponíveis na literatura. As variáveis dessas equações ficaram definidas como variáveis de entrada para os modelos e foram determinadas em laboratório, usando 12 modelos de tubos emissores, com diferentes diâmetros, espaçamentos entre emissores e seções transversais médias dos emissores. Os dois modelos apresentaram ótimo ajuste aos dados observados, com coeficiente de determinação ajustado de 0,977 e 0,99 para os modelos obtidos a partir de regressão linear múltipla e a partir de análise dimensional, respectivamente. O modelo obtido a partir de análise dimensional considera a variação de diâmetro que o tubo sofre com a pressão da água. Ambos os modelos são de fácil uso. / The uniformity of emission along a lateral line of drip irrigation, is related of the pressure variation caused by head losses during the flow in dripline and the water outlet by emitters along the lateral line. To calculate the maximum length of lateral lines, we need to accurately determine the variation of pressure to meet a pre-established criterion of flow variation. The objective of this work was to develop methodology for calculating the head loss in driplines with emitters type \"bóbi\". For this we developed two models, one using multiple linear regression and one using dimensional analysis. Both were based on equations of continuos head losses in the tube and located in the emitters available in the literature. The equations of these variables were defined as input variables for the models and were determined in the laboratory, using 12 models driplines with different diameters, spacing between emitters and emitters of medium cross sections. Both models showed good fit to the data observados with a determination coefficient of 0.977 for the model obtained from multiple linear regression and to 0.99 obtained from dimensional analysis. The model obtained from the dimensional analysis considers the change in diameter than the tube suffers the water pressure. Both models are easy to use.

Orientador: Jose Ricardo de Albergaria Barbosa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-03T23:42:34Z (GMT). No. of bitstreams: 1 FreireFilho_FranciscoWagnerVasconcelos_D.pdf: 1185958 bytes, checksum: d471fe34fa012fb2c3725a04c776609d (MD5) Previous issue date: 2004 / Resumo: O objetivo deste trabalho foi comparar dois sistemas de distratores osteogênicos alveolares justa-ósseos de 9mm de abertura máxima de fabricação nacional. Foram analisadas duas marcas comerciais (Grupo I e Grupo II), através das avaliações dimensionais dos distratores e parafusos, da resistência à tração dos distratores e da resistência à flexão e à torção dos parafusos. Na avaliação dimensional foram utilizados dez distratores de cada fabricante e quarenta parafusos, sendo dez de cada tamanho oferecido, 1,3 x 5mm e 1,3 x 7mm do grupo I e 1,5 x 5mm e 1,5 x 7mm do grupo II. Os dados foram submetidos ao teste dos postos assinalados de Wilcoxon para os distratores e o teste de Friedman para os parafusos. No teste de resistência à tração foram utilizados dez distratores de cada marca comercial e os resultados submetidos ao teste t Student. No teste de resistência à flexão foram utilizados quarenta parafusos e aplicados os testes F e de Tukey, ao nível de significância de 5%. No teste de resistência à torção, foram utilizados dez parafusos de cada fabricante, sendo do tipo 1,3 x 5mm do grupo I e 1,5 x 5mm do grupo II e os resultados submetidos ao teste t Student. Os distratores do grupo II apresentaram menor variação das mensurações realizadas, porém não houve diferença estatística entre os parafusos de ambas as marcas. Os distratores do grupo II foram estatisticamente mais resistentes à tração. Os parafusos de 1,5x5mm do grupo II foram os mais resistentes à flexão e à torção / Abstract: The aim of this study was to perform a comparative analysis between two different alveolar distractions devices, of 9mm length, built by manufactured in Brazil. These two different devices were provided by companies (group I and group II). The analysis consisted of a macroscopic assessment from the distraction devices and its screws, followed by a traction resistance of the devices and torsion and bending resistance of the screws. Were used, for macroscopic assessment, ten distraction devices and forty screws, which included ten screws of every length offered by each company. Data was submitted to the Wilcoxon test for devices and Friedman test for screws. Ten distraction devices from each company were used for the traction resistance, and its results were submitted to the Student t test. Forty screws were used for the bending resistance. Values were compared trough F and Tukey test, with 5% significance. For the torsion resistance, ten screws from each company were used. The 1.3 X 5mm screws from group I and the 1.5 X 5mm from group II were chose to realize this test, and its results were submitted to the Student t test. Devices from group II presented less variation of its measurements, but there were not any statistical difference between the screws. Group II devices were tatistically more resistant to traction. Screws 1.5x5mm, produced by group II, were more resistant to bending and to torsion / Doutorado / Cirurgia e Traumatologia Buco-Maxilo-Faciais / Doutor em Clínica Odontológica

Compliant suspensions are often used in micromechanical devices and precision mechanisms as substitutes for kinematic joints. While their small-displacement behavior is easily captured in simple formulae, large-displacement behavior requires nonlinear finite element analysis. In this work, we present a method that helps capture the geometrically nonlinear behavior of compliant suspensions using parameterized non-dimensional maps. The maps are created by performing one nonlinear finite element analysis for any one loading condition for one instance of a suspension of a given topology and fixed proportions. These maps help retrieve behavioral information for any other instance of the same suspension with changed size, cross-section dimensions, material, and loading. Such quantities as multi-axial stiffness, maximum stress, natural frequency, etc. ,can be quickly and accurately estimated from the maps. These quantities are non-dimensionalized using suitable factors that include loading, size, cross-section, and material properties. The maps are useful in not only understanding the limits of performance of the topology of a given suspension with fixed proportions but also in design. We have created the maps for 20 different suspensions. Case studies are included to illustrate the effectiveness of the method in microsystem design as well as in precision mechanisms. In particular, the method and 2D plots of non-dimensional kinetoelastic maps provide a comprehensive view of sensitivity, cross-axis sensitivity, linearity, maximum stress, and bandwidth for microsensors and microactuators.

This thesis gives a comprehensive characterization of lightweight non-oxide ceramic materials for ballistic applications, an overview of production technologies and processing of boron carbide B4C and its ceramic-based composites. A framework for evaluating the ballistic resistance of the material based on mechanical properties is shown there. It can be used in experiments without normalized equipment. The experiments including B4C + Si, B4C + Ti composites, and application of Spark plasma sintering (SPS) were designed according to outputs from the theoretical part. The volume fractions of Si, Ti dopants were optimized based on ongoing chemical reactions during sintering. The obtained samples were subjects of mechanical testing which results were compared to identify the ideal ratio of matrix and reinforcement. As the best suited material for ballistic protection, B4C + 1,0 obj. % reaches these values of parameters; hardness = 3502 ± 122 HV1; fracture toughness KIC = 2,97 ± 0,03 MPam^0,5.

Afin de se rapprocher des conditions du mélange homogène du moteur essence, plusieurs fluides sont injectés dans l'atmosphère à une pression amont et une température variées. Cinq prototypes d'injecteurs réels trois-trous de Continental ont été utilisés. En augmentant la pression d'injection, l'écoulement passe par quatre régimes où le niveau de développement de cavitation varie. Le coefficient de décharge Cd dépend essentiellement du nombre de cavitation. Au point critique de cavitation, deux corrélations ont été obtenues reliant respectivement Cd et le nombre de cavitation critique au nombre de Reynolds correspondant. Le jet en champ proche est gouverné par trois nombres sans dimensions : celui de Weber, de Reynolds et de cavitation. L'effet de chacun d'eux sur l'angle du jet à la sortie a été obtenu. La comparaison des résultats entre deux injecteurs a montré que le rapport entre la longueur et le diamètre de l'orifice est d'une influence d'ordre 1 sur l'angle du jet. / In order to get closer to the homogeneous mixture conditions of a gasoline engine, different fluids are injected into the atmosphere at varying upstream pressure and temperature. Five three-hole real injector prototypes from Continental were used. When injection pressure is increased, the internal flow goes through four regimes where the cavitation development level varies from one to another. The discharge coefficient Cd was found mainly dependent on the cavitation number. At the cavitation critical point, two correlations between Cd and the critical cavitation number on one side respectively, and the correspondent Reynolds number on the other side were found. The near field jet is ruled by three dimensionless numbers : Weber, Reynolds and cavitation. The effect of each one of them on the jet angle at the orifice outlet was obtained. By comparing the results of two injectors, it was found that the length over diameter ratio has a first order influence on the jet angle.

<p>Musculoskeletal degradation and musculoskeletal injuries place a substantial burden on the healthcare system. Advancing the understanding and prevention of the injury potential associated with these injuries in various demographics as well as advancing performance optimization requires knowledge of the loading distribution among the various musculoskeletal tissues at the joints. Accurate muscle force estimates are needed for characterizing these distributions due to their influence on the loading of the system. This dissertation discusses</p> <p>the development and validation of a physiologically-driven skeletal muscle force model that is suitable for application on an individualized level. The derivation of the skeletal muscle force model began with dimensional analysis and a selection of critical parameters that define muscle force generation. One of the key parameters included was measured muscle voltage using electromyography sensors. This provided the model with the ability to be easily used</p> <p>in application-based studies. It also incorporated the muscle force-length, force-velocity, and force-frequency curves, providing an even stronger physiological basis to the model. Validation was performed by multiple studies using experimental data from subjects conducting exercises chosen to target specific muscles of interest. Data was collected from a Vicon Vero motion capture system, an instrumented Bertec treadmill, and Delsys Trigno electromyography sensors. The first study analyzed the ankle joint of seventeen subjects using the two Newton-Euler equations of rigid body motion and the skeletal muscle force model. The average percent error across all subjects was 8.2% and ranged from 4.2% to 15.5%. The second study analyzed the sensitivity of two sets of parameters within the model. The first was conducted on a set of observed and fitted constants from the dimensionless pi terms and aimed to identify which, if any, could be excluded from an optimization routine. Results indicated that only two of the nine constant parameters needed to be optimized. The second sensitivity analysis focused on the anatomical kinematic parameters in order to identify the impact that the incorporation of MRI scans for subject-specific anatomical models would have on the accuracy of the model’s output. Results demonstrated sensitivity to the muscle insertion points, suggesting that the use of MRI scans could increase the accuracy of the model. The third study was a case study focused on evaluating the assumption of a constant within the skeletal muscle force model remaining constant over time. Results indicated that the collection of maximum EMG recordings for these studies may not have been controlled to a desirable level and that the inclusion of specialized equipment for maximum EMG recordings would likely validate this assumption. The final study analyzed the</p> <p>knee joint of ten subjects in a similar fashion to that of the ankle joint. The goal was to observe the model’s performance on a more anatomically complex joint. The average percent error across all subjects was 20.6%, approximately two times higher than the ankle joint.</p> <p>However, the majority of the error associated with this study came from the deviation in calculated moments about an axis of much smaller importance and magnitude than the primary flexion/extension axis. When errors were excluded from this axis, the average percent error for all subjects was 8.8%, almost identical to that of the ankle joint application. These findings as a whole indicate that the model has predictive ability and is capable of providing reasonable estimates of both muscle forces and surrounding musculoskeletal tissue loading. Therefore, the model could be used in various biomechanical advancements and applications in injury prevention, performance optimization, tissue engineering, prosthetic design, and more.</p>

Green adsorption media with the inclusion of renewable and recycled materials can be applied as a stormwater best management practice for copper removal. A green adsorption media mixture composed of recycled tire chunk, expanded clay aggregate, and coconut coir was physicochemically evaluated for its potential use in an upflow media filter. The results found that the use of the green adsorption media mixture in isolation or the coconut coir with an expanded clay filtration chamber could be an effective and reliable stormwater best management practice for copper removal. A suite of tests were conducted on the media mixture and the individual media components including studies of isotherm, reaction kinetics, column adsorption and reaction kinetics. Batch adsorption tests revealed that the media and media mixture follow both the Freundlich and Langmuir isotherm models and that the coconut coir had the highest affinity for copper. A screening of desorbing agents revealed that hydrochloric acid has good potential for copper desorption, while batch tests for desorption with hydrochloric acid as the desorbing agent showed the data fit the Freundlich isotherm model. Reaction kinetics revealed that the adsorption reaction took less than 1 hour to reach equilibrium and that it followed pseudo-second order kinetics for the mixture and coconut. Desorption kinetic data had high correlation with the pseudo-second order model and revealed a rapid desorption reaction. Batch equilibrium data over 3 adsorption/desorption cycles found that the coconut coir and media mixture were the most resilient and demonstrated that they could be used through 3 or more adsorption/desorption cycles. The coconut coir also performed the best under dynamic conditions, having an equilibrium uptake of 1.63 mg?g-1, compared to 0.021 mg?g-1 at an influent concentration of 1.0 mg?L-1 and a hydraulic retention time of 30 minutes. A physical evaluation of the media found the macro-scale properties, such as particle size distribution and mass-volume relationships, and observed the micro-scale properties such as surface and pore microstructures, crystalline structures, and elemental composition. FE-SEM imaging found a strong correlation between the porosity of the micro pore structure and the adsorptive capacity. The equilibrium and dynamic adsorption testing results were confirmed by elemental analysis, which showed measureable quantities of copper in the coconut coir and media mixture after adsorption followed by partial desorption. A new scaling-up theory was developed through a joint consideration of the Damköhler and Péclet numbers for a constant media particle size such that a balance between transport-controlled and reaction-controlled kinetics can be harmonized. A series of column breakthrough tests at varying hydraulic residence times revealed a clear peak adsorptive capacity for the media mixture at a Damköhler number of 2.7. The Péclet numbers for the column breakthrough tests indicated that mechanical dispersion is an important effect that requires further consideration in the scaling-up process. However, perfect similitude of the Damköhler number cannot be maintained for a constant media particle size, and relaxation of hydrodynamic similitude through variation of the Péclet number must occur.

Geosynthetic tubes filled with a slurry-mix are considered. The mix is usually dredged from a nearby area and pumped directly into the tubes. The tubes are used in a variety of applications including breakwaters, groins, and temporary levees. This thesis considers single and stacked geosynthetic tubes resting on rigid and deformable foundations. A two-dimensional analysis is performed on the cross-section of a very long tube. The program Mathematica is utilized for the analysis. A few assumptions are made regarding the general behavior of the tube. The tube is assumed to be an inextensible membrane with no bending stiffness. To allow for a closed-form integral solution, it is assumed that no friction exists between the tubes and at the foundation. A single tube, two stacked tubes, and a 2-1 formation are studied. Both rigid and deformable foundations are considered. The deformable foundation is modeled as a tensionless Winkler foundation with normal forces proportional to the downward deflection of the ground. An external water load on one side is also investigated for a single tube and a 2-1 formation, with rigid blocks to prevent the structure from sliding along the ground. Example cross-sectional profiles are given. Results from the analysis include structure height, circumferential tension, and ground deflections. / Master of Science