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1
Nanduru, Venkata Giri. "Ramp control strategies and geometric design implications of high-speed automated transportation systems." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09052009-040424/.
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Asgarifard, Aniran. "Static Machines, Fragile Loads." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71804.
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Ramps are usually perceived as utilitarian objects emerging from standardized guidelines for architecture and landscape architecture. But closer examination reveals they can be quite beautiful and poetic. What we commonly call ramps, Galileo referred to as inclined planes, counting them as one of six classical simple machines in Le Meccaniche (On Mechanics) . Because inclined planes are actually static machines that do not require any energy to run.
They do not discriminate among users. This thesis explores the work of the ramp in moving fragile loads, such as human beings.Master of Landscape Architecture
3
Pajjuri, Srinivas Reddy. "Computer model to simulate truck accidents on exit ramps." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-08182009-040509/.
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Madjidi, Saeid. "Low velocity impact of obliquely inclined composite plates." Thesis, University of the West of Scotland, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535957.
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A study into the performance of CSM (Chopped Strand Mat) reinforced polyester laminates subject to low velocity impact at oblique angles is presented. The investigation encompasses both an experimental and theoretical assessment of the impact event, viz damage tolerance and residual material properties of flat, clamped composite plates. A short introduction is followed by a comprehensive review of the most relevant published literature on all aspects of impact induced damage. A theoretical analysis based on the use of damage toughness parameters is formulated to predict the residual tensile strength and stiffness properties of impact damaged plates. The analysis is further extended to determine the total internal stress distribution in the system. A combination of Hertzian contact, plate bending and finite element solution are used to establish the influence of plate inclination on the resulting stress state. Several common failure criteria were used to predict the extent of the damage. These predictions are compared with experimental data. Results from an extensive experimental programme are presented A fully instrumented test rig was used to assess the influence of imparted energy, impact force, and plate indentation with respect to surface indentation profiles, damage areas and micrographic evidence. The theoretical and experimental results are graphically presented, discussed in detail and exhibit good agreement. The study is finally concluded with comments summarising the most pertinent points derived from the present investigation together with recommendations for further work.
5
Goujon, Celine. "Ecoulements granulaires bidisperses sur plans inclines rugueux." Phd thesis, Université de Provence - Aix-Marseille I, 2004. http://tel.archives-ouvertes.fr/tel-00008984.
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Pour comprendre la grande mobilité des écoulements naturels, nous nous sommes intéressés à l'étude des écoulements granulaires monodisperses et bidisperses. L'étude des écoulements granulaires monodisperses a montré l'existence d'un diamètre de billes pour lequel la friction est maximum. Ce diamètre dépend des caractéristiques du plan rugueux (diamètre des rugosités et espacement entre les rugosités), et peut être déterminé à l'aide d'un modèle de stabilité sans paramètre ajustable. L'étude des écoulements bidisperses a mis en évidence, du fait de la répartition inhomogène des billes lors de l'écoulement de nombreuses interactions, réparties suivant deux effets : les “effets de lignes” qui ont une influence sur la morphologie du dépôt (formation ou non de doigt) et les “effets d'interface” (interactions des petites billes avec le plan rugueux et interaction des petites billes avec les grosses billes) qui ont une influence sur l'épaisseur du dépôt et sur la rhéologie de ces écoulements.
6
Savoie, Andrée J. "Eliminating scour and excessive volumes in settling tanks using inclined plates." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ36740.pdf.
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So, Ling-yue Daphne, and 蘇令如. "Inclined [expression], [impression]: an urbanconnector/collector on the inclined surface at foothill." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31986031.
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Leite, Bruno Medeiros. "Modelagem do absorvedor e do gerador de ciclos de refrigeração por absorção de calor com o par amônia/água baseados na tecnologia de filme descendente sobre placas inclinadas." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3150/tde-16062016-080831/.
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Esse trabalho constitui o desenvolvimento da modelagem térmica e simulação por métodos numéricos de dois componentes fundamentais do ciclo de refrigeração por absorção de calor com o par amônia/água: o absorvedor e o gerador. A função do absorvedor é produzir mistura líquida com alta fração mássica de amônia a partir de mistura líquida com baixa fração mássica de amônia e mistura vapor mediante retirada de calor. A função do gerador é produzir mistura líquido/vapor a partir de mistura líquida mediante o fornecimento de calor. É proposto o uso da tecnologia de filmes descendentes sobre placas inclinadas e o método de diferenças finitas para dividir o comprimento da placa em volumes de controle discretos e realizar os balanços de massa, espécie de amônia e energia juntamente com as equações de transferência de calor e massa para o filme descendente. O objetivo desse trabalho é obter um modelo matemático simplificado para ser utilizado em controle e otimização. Esse modelo foi utilizado para calcular as trocas de calor e massa no absorvedor e gerador para diversas condições a partir de dados operacionais, tais como: dimensões desses componentes, ângulo de inclinação da placa, temperatura de superfície e condições de entrada da fase líquida e vapor. Esses resultados foram utilizados para estabelecer relações de causa e efeito entre as variáveis e parâmetros do problema. Os resultados mostraram que o ângulo de inclinação da placa ótimo tanto para o absorvedor como para o gerador é a posição vertical, ou 90°. A posição vertical proporciona o menor comprimento de equilíbrio (0,85 m para o absorvedor e 1,27 m para o gerador com as condições testadas) e se mostrou estável, pois até 75° não foram verificadas variações no funcionamento do absorvedor e gerador. Dentre as condições testadas para uma placa de 0,5 m verificou-se que as maiores efetividades térmicas no absorvedor e gerador foram respectivamente 0,9 e 0,7 e as maiores efetividades mássicas no absorvedor e gerador foram respectivamente 0,6 e 0,5. É esperado que os dados obtidos sejam utilizados em trabalhos futuros para a construção de um protótipo laboratorial e na validação do modelo.This work presents the development of thermal modeling and simulation by numerical methods of two fundamental components of an ammonia/water heat absorption refrigeration cycle: absorber and generator. The function of the absorber is produce high ammonia mass fraction liquid mixture from low ammonia mass fraction liquid mixture and vapor mixture by heat removal. The function of the generator is produce vapor mixture from liquid mixture by heat addition. It is used the falling film technology over Inclined plates and the finite difference method to slice the plate length in discreet control volumes and do the mass, ammonia specie and energy balances along with the heat and mass transfer equations to the falling film. The aim of this work was obtain a simplified mathematical model to be used in control and optimization. This model was used to calculate the exchanges of heat and mass of both absorber and generator in many conditions from operational data such as: components dimensions, plate angle, surface temperature and inlet condition of liquid and vapor phase. These results were used to establish relations of cause and effect between the problem variables and parameters. The results showed that the optimum plate angle for both absorber and generator is the vertical position, or 90°. The vertical position provides the smallest equilibrium length (0,85 m to the absorber and 1,27 to the generator in tested conditions) and it proves itself to be stable, because until 75° no variations in the function of absorber and generator were detected. Among the tested condition for a 0,5 m plate length the highest thermal effectiveness for absorber and generator were respectively 0,9 and 0,7 and the highest mass effectiveness for absorber and generator were respectively 0,6 and 0,5. The obtained data is expected to be used in future works for the construction of a laboratorial prototype and in the model validation.
9
Goujon, Céline. "Ecoulements granulaires bidisperses sur plans inclinés rugueux." Aix-Marseille 1, 2004. http://www.theses.fr/2004AIX11053.
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Pour comprendre la grande mobilité des écoulements naturels, nous nous sommes intéressés à l'étude des écoulements granulaires monodisperses et bidisperses. L'étude des écoulements granulaires monodisperses a montré l'existence d'un diamètre de billes pour lequel la friction est maximum. Ce diamètre dépend des caractéristiques du plan rugueux (diamètre des rugosités et espacement entre les rugosités), et peut être déterminé à l'aide d'un modèle de stabilité sans paramètre ajustable. L'étude des écoulements bidisperses a mis en évidence, du fait de la répartition inhomogène des billes lors de l'écoulement, de nombreuses interactions, répartis suivant deux effets : les « effets de lignes » qui ont une influence sur la morphologie du dépôt (formation ou non de doigt) et les « effets d’interface » (interactions des petites billes avec le plan rugueux et interaction des petites billes avec les grosses billes) qui ont une influence sur l’épaisseur du dépôt et sur la rhéologie de ces écoulements.
10
Baker, Steven Jeffrey. "Numerical experiments with models for a particle on a rough inclined plane." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/28821.
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Krivtsova, A. V., A. G. Meleshko, G. A. Gorelikov, Yu A. Fridman, and Ph N. Klevets. "Influence of the Mechanical Boundary Conditions on Dynamic and Static Properties of the Ferromagnetic with Competing Anisotropies." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35347.
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The phase transitions on the material constants are investigated for the semi-infinite ferromagnetic
with the mechanical boundary conditions and competing inclined single-axis and easy-plane anisotropies.
The phase state soft he system and the dispersion laws of coupled magnetoelastic waves are determined.
Analysis of the spectra of elementary excitations has allowed to plot the phase diagram of the system.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35347
12
Hytopoulos, Evangelos. "Laminar, steady and unsteady flow over inclined plates in two and three dimensions." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-06082009-170928/.
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Rosa, Daniel Jordão de Magalhães. "Caracterização da radiação solar: o caso da Cidade Universitária/USP e da Ilha do Cardoso/Cananéia." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/86/86131/tde-18022014-113416/.
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A ética e a luta pela equidade social e melhoria da qualidade de vida das populações impulsiona a busca pela universalização do atendimento do serviço energético e pela utilização racional dos recursos renováveis existentes em cada local. Nesse sentido, o aproveitamento da energia solar apresenta-se como uma excelente alternativa, seja para disponibilizar pequenas quantidades de energia elétrica, utilizando-se de geradores fotovoltaicos, seja para o aquecimento de água ou ainda para o condicionamento ambiental de edificações. Em qualquer desses casos, são necessárias informações confiáveis sobre o recurso solar disponível. O presente trabalho se insere nesse contexto buscando, além de propor um padrão para instalação de estações solarimétricas, para o sistema de unidades utilizado e para a rotina de calibração e manutenção dos equipamentos, caracterizar a radiação solar no Estado de São Paulo, tendo como um de seus objetivos oferecer dados de irradiação solar diária média mensal, centrando a atenção na cidade de São Paulo e no Vale do Ribeira, no litoral sul do Estado de São Paulo. Esta última área, localizada no município de Cananéia, possui baixos índices de eletrificação rural e grande potencial de utilização de sistemas fotovoltaicos para suprir a demanda de residências isoladas. Como, em geral, os painéis para aproveitamento do recurso solar são instalados em uma determinada inclinação, para se dimensionar corretamente um sistema é necessário transformar os dados de irradiação solar de plano horizontal para plano inclinado. Assim, foram testados os diversos modelos presentes na literatura para o cálculo da irradiação global diária mensal em plano inclinado a partir de dados em plano horizontal. Todos esses modelos necessitam de dados de irradiação difusa, ou seja, a irradiação proveniente de toda a esfera celeste, menos diretamente do Sol, para poderem ser utilizados. Dessa maneira, o presente trabalho buscou testar os diversos modelos que calculam a irradiação difusa a partir da irradiação global e, com a verificação da inadequação desses, propõe uma nova correlação, mais apropriada para nossa realidade.Ethics, and the struggle both for social equity and the improvement of the standard of living of populations, drive the efforts for both the universalization of energy provision and the rational utilization of existing renewable resources. Accordingly, utilizing solar energy presents itself as an excellent alternative, whether it is to make available small quantities of electric energy, utilizing photovoltaic generators, for heating water, or for environmental conditioning. Whatever the case, it is necessary to have reliable information on available solar resource. This work seeks to develop standards for implementation of solarimetric stations, for the unit system to be utilized and for the routine of calibration and maintenance of equipment. It also seeks to characterize solar radiation in the state of São Paulo, with one of its objectives being the supply of data of monthly average daily irradiation in the city of São Paulo and the Ribeira Valley (south coast of São Paulo state). The latter has low levels of rural electrification and great potential for utilizing photovoltaic systems in the supply of energy for isolated residences. As solar panels are generally installed on a sloped surface, the correct dimensioning of systems requires converting solar irradiation data from horizontal plane to tilted plane. Thus, several models presented in the literature that calculate monthly average daily irradiation on inclined plane from available data measured on horizontal plane were tested. All such models need diffuse irradiation data, that is, irradiation originating from the entire sky, except that originating directly from the sun, to be utilized. For this reason, this work sought to test several models that establish correlations for the calculation of diffuse solar irradiation from global solar irradiation. As the inadequacy of such models was verified, this proposes a new correlation that is more appropriate for the conditions of the state of São Paulo.
14
Abbatt, Joanna. "Spine and pelvis coupled movements in the frontal plane during inclined walking and running." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33267.
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Spinal adaptive response in the frontal plane was investigated in relationship to pelvic unleveling during gait. Kinematic data were collected from 10 healthy adult subjects (5 male, 5 female) for walking and running on the treadmill at self-selected speeds. Spine and pelvic kinematic patterns and ranges of motion (ROM) were investigated with gender, speed and slope as factors. Speed and slope had the greatest impact on changes in the amplitude of the spine's kinematic patterns. Interaction effects were seen for speed and slope for the ROM, particularly of the greater trochanter (p < .047), PSIS (p < .011) and for the shoulders (p < 0.077). Gender presented more changes in the pelvic kinematics than the spine's kinematics. A significant trend in the females of greater ROM for T8 with increases in speed and slope was shown (p < 0.001). From this study it was concluded that speed, slope and gender were significant factors that affect the spine's ability to adapt to pelvic unleveling. In all conditions there was a coupled relationship found between the thoracic spine, lumbar spine and pelvis. In particular there was an oppositional movement found within the spine such that as the lumbar spine had convexity towards the swing leg then the thoracic spine had the opposite convexity. Hence, these factors are important when assessing posture and biomechanics of running and walking.
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Kasapoglu, Serkan. "A Pseudospectral Analysis Of Laminar Natural Convection Flow And Heat Transfer Between Two Inclined Parallel Plates." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606492/index.pdf.
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Three dimensional laminar natural convection flow of and heat transfer in incompressible air between two inclined parallel plates are analyzed with the Boussinesq approximation by using spectral methods. The plates are assumed to be infinitely long in streamwise and spanwise directions. For these directions, periodic boundary conditions are used and for the normal direction constant wall temperature and no slip boundary conditions are used. Unsteady Navier-Stokes and energy equations are solved using a pseudospectral C code in order to obtain velocity and temperature profiles inside the channel. Fourier series are used to expand the variables in x and z directions, while Chebyshev polynomials are used to expand the variables in y direction. By using the temperature distribution between the plates, local and average Nusselt numbers (Nu) are calculated. Nu values are correlated with φ
,which is the inclination angle, and with Racos&
#966
to compare the results with the literature. Additionally, non-dimensional velocity values and streamlines of the fluid are presented with proper plots.
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Baxter, Steven J. "Numerical simulation of three-dimensional free surface film flow over or around obstacles on an inclined plane." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11343/.
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Within the bearing chamber of a gas turbine aero-engine, lubrication of the shaft and other bearings is achieved by an oil film which may become significantly disturbed by interacting with a range of chamber geometries which protrude from the chamber wall. Minimizing these disturbances and preventing possible dry areas is crucial in optimizing a bearing chambers design. In addition, multiple obstructions may be located close to one another, resulting in a more complex disturbed film profile than by individual obstacles. Prediction of the disturbance of the film is an important aspect of bearing chamber design. For analysis of the film profile over or around a local obstacle, typical bearing chamber flows can be approximated as an incompressible thin film flow down an inclined wall driven by gravity. The Reynolds number of thin film flows is often small, and for the bulk of this thesis a Stokes flow assumption is implemented. In addition, thin films are often dominated by surface tension effects, which for accurate modelling require an accurate representation of the free surface profile. Numerical techniques such as the volume of fluid method fail to track the surface profile specifically, and inaccuracies will occur in applying surface tension in this approach. A numerical scheme based on the boundary element method tracks the free surface explicitly, alleviating this potential error source and is applied throughout this thesis. The evaluation of free surface quantities, such as unit normal and curvature is achieved by using a Hermitian radial basis function interpolation. This hermite interpolation can also be used to incorporate the far field boundary conditions and to enable contact line conditions to be satisfied for cases where the obstacle penetrates the free surface. Initial results consider a film flowing over an arbitrary hemispherical obstacle, fully submerged by the fluid for a range of flow configurations. Comparison is made with previously published papers that assume the obstacle is small and / or the free surface deflection and disturbance velocity is small. Free surface profiles for thin film flows over hemispherical obstacles that approach the film surface are also produced, and the effects of near point singularities considered. All free surface profiles indicate an upstream peak, followed by a trough downstream of the obstacle with the peak decaying in a “horseshoe” shaped surface deformation. Flow profiles are governed by the plane inclination, the Bond number and the obstacle geometry; effects of these key physical parameters on flow solutions are provided. The disturbed film profiles over multiple obstacles will differ from the use of a single obstacle analysis as their proximity decreases. An understanding of the local interaction of individual obstacles is an important aspect of bearing chamber design. In this thesis the single obstacle analysis is extended to the case of flow over multiple hemispheres. For obstacles that are separated by a sufficiently large distance the flow profiles are identical to those for a single obstacle. However, for flow over multiple obstacles with small separation, variations from single obstacle solutions maybe significant. For flow over two obstacles placed in-line with the incident flow, variations with flow parameters are provided. To identify the flexibility of this approach, flows over three obstacles are modelled. The calculation of flows around obstacles provides a greater challenge. Notably, a static contact line must be included such that the angle between the free surface and the obstacle is introduced as an extra flow parameter that will depend both on the fluid and the obstacle surface characteristics. The numerical models used for flow over hemispheres can be developed to consider film flow around circular cylinders. Numerical simulations are used to investigate flow parameters and boundary conditions. Solutions are obtained where steady flow profiles can be found both over and around a cylindrical obstacle raising the awareness of possible multiple solutions. Flow around multiple obstacles is also analyzed, with profiles produced for flow around two cylinders placed in various locations relative to one another. As for flow over two hemispheres, for sufficiently large separations the flow profiles are identical to a single obstacle analysis. For flow around two obstacles spaced in the direction of the flow, effects of altering the four governing parameters; plane inclination angle, Bond number, obstacle size, and static contact angle are examined. The analysis of flow around three cylinders in two configurations is finally considered. In addition, for two obstacles spaced in-line with the incident flow, the numerical approaches for flow over and flow around are combined to predict situations where flow passes over an upstream cylinder, and then around an identical downstream cylinder. The final section of this thesis removes the basic assumption of Stokes flow, through solving the full Navier-Stokes equations at low Reynolds number and so incorporating the need to solve nonlinear equations through the solution domain. An efficient numerical algorithm for including the inertia effects is developed and compared to more conventional methods, such as the dual reciprocity method and particular integral techniques for the case of a three-dimensional lid driven cavity. This approach is extended to enable calculation of low Reynolds number film profiles for both flow over and around a cylinder. Results are compared to the analysis from previous Stokes flow solutions for modest increases in the Reynolds number.
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Silveira, Silvana Rocha da. "Análise do comportamento do centro de pressão (CoP) na posição ereta quieta em situação de aclive, declive e horizontal diante da movimentação cefálica." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152176.
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O controle postural é um requisito imprescindível para a execução das habilidades motoras durante as tarefas das atividades de vida diária, logo, há a necessidade constante de ajuste dos segmentos corporais para garantir a autonomia e independência da mobilidade humana, dentro da conjuntura da acessibilidade. Os ajustes posturais são resultantes da interação do sistema sensório–motor e da sua correlação com o meio ambiente, produzindo orientação e estabilidade postural esperada durante a execução das atividades diárias, sendo ela estática ou dinâmica. Deste modo, o objetivo do estudo foi analisar e comparar o comportamento do centro de pressão na posição ereta quieta em situação de aclive, declive e horizontal diante da movimentação cefálica, entre três grupos com faixas etárias diferentes. O estudo transversal foi composto de 28 indivíduos, de ambos os gêneros, divididos em três grupos por faixas etárias (20 a 29 anos, 30 a 59 anos e acima de 60 anos), de acordo com os critérios de inclusão. O instrumento de avaliação constituiu-se por uma plataforma de força acoplada numa rampa com 15° e em um platô horizontal. A coleta dos dados seguiu um protocolo pré-determinado, envolvendo a posição ereta quieta com olhos abertos (OA), em quatro condições cefálicas, em três situações: aclive, declive e horizontal. Os dados obtidos foram trabalhados por meio do programa Matlab® e para a análise estatística foi aplicado o programa Action Start, utilizando a análise descritiva dos dados e o Teste Anova: fator único, Teste-t: duas amostras em par para média e Teste-t: duas amostras presumindo variâncias diferentes. Os resultados do presente estudo apontaram que a oscilação do CoP na posição ereta quieta com olhos abertos, se alteram diante das condições em que o segmento cefálico encontra – se em movimento, independente das situações de aclive, declive e horizontal, principalmente nos grupos com faixa etária igual ou superior a 60 anos
Postural control is an essential requirement for the performance of motor skills during daily activities, so there is a constant need to adjust the body segments to ensure the autonomy and independence of human mobility, within the context of accessibility. Postural adjustments result from the interaction of the sensor - motor system and its correlation with the environment, producing orientation and postural stability expected during the execution of daily activities, being static or dynamic. Thus, the objective of the study was to analyze and compare the behavior of the pressure center in the standing upright position in slope, slope and horizontal situation in front of the head movement, between three groups with different age groups. The cross-sectional study consisted of 28 individuals of both genders, divided into three groups by age group (20 to 29 years, 30 to 59 years and above 60 years), according to the inclusion criteria. The evaluation instrument consisted of a force platform coupled on a ramp with 15 ° and a horizontal plateau. Data collection followed a predetermined protocol, involving the standing upright position with open eyes (OA), in four cephalic conditions, in three situations - slope, slope and horizontal. The data obtained were worked through the Matlab® program and for the statistical analysis the Action program was applied using descriptive data analysis and the Anova test: single factor, t-test: two samples in pairs for mean and t-test: Two samples assuming different variances. The results of the present study pointed out that the oscillation of the CoP in the quiet standing position with open eyes, are altered by the conditions in which the cephalic segment is in motion, independent of slope, slope and horizontal situations, Aged 60 years or over
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Benedetti, Arnaud. "Ecoulement des milieux granulaires cohésifs soumis à des vibrations." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4717/document.
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Nous nous intéressons à l'écoulement de milieux granulaires cohésifs soumis à des vibrations horizontales en vue d'une application au remplissage des moules de presse. L'effet des vibrations est analysé pour un grain ou un milieu granulaire déposé sur un plan incliné et un milieu granulaire contenu dans une conduite verticale de section constante. Pour un grain polyédrique, trois régimes sont identifiés : stick, stick-slip et slip. Un modèle basé sur le bilan des forces appliquées à un grain a permis de préciser les limites de ces trois domaines. La vitesse des grains tend vers une asymptote lorsque l'inclinaison est inférieure à 0,7 fois l'angle de frottement entre les grains et le plan. Par ailleurs, l'inertie du grain conduit à une réduction de l'amplitude de son oscillation lorsque l'accélération augmente. La comparaison modèle-expérience permet d'estimer le coefficient de frottement. Pour un milieu granulaire de faible épaisseur, nous retrouvons les mêmes tendances. Les milieux granulaires épais sont le lieu de forts cisaillements provoquant leur étalement très rapide. En conduite verticale, une compétition s'établit entre les déplacements horizontal et vertical des particules. Selon l'inertie, les vibrations appliquées pourront conduire soit à une dilatance soit à une compaction. Cette dernière provient du déplacement de la conduite et du milieu granulaire en sens opposé pendant une partie d'une période de vibration. Si le phénomène de compaction atteint le centre de la conduite, il se forme des arches qui bloquent l'écoulement. Les observations faites à l'échelle mésoscopique permettent d'interpréter les vitesses d'écoulement mesurées à l'échelle macroscopiqueWith the target to improve the feeding step during the moulding process, we study the flow of cohesive granular matter submitted to vibration. Vibration effects are first analyzed on the sliding motion of a single particle on inclined plane and also on granular matter sample deposited on an inclined plane or in a vertical funnel. For a single particle, three regimes are identified: stick, stick-slip and slip regimes. A simple model based on the movement equation of one grain allows to determinate the limits between the three regimes. The grain velocity reaches asymptote when the plane inclination is below 0.7 times the friction angle between the grain and the substrate. Otherwise, when the acceleration increases, the grain inertia leads to reduce the transverse amplitude of the grain oscillation motion. The comparison between experimental and numerical results allows to estimate a value for the friction coefficient parameter. For a granular sample, we find the same tendencies. Thick granular layers are submitted to high shear, causing a fast spreading. In vertical funnel, there is a competition between vertical and horizontal motions. Depending on granular inertia, submitted vibrations could lead to dilatancy due to the shear or lead to compaction. This compaction is due to an opposite motion direction between the sample and the funnel during one part of the period vibration. If the compaction reaches the center of the funnel, arches are formed and jammed the flow. Observations realized at mesoscopic scale allow to interpret flow velocities measured at macroscopic scale
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Briançon, Laurent. "Stabilité sur pentes des dispositifs géosynthétiques : caractérisation du frottement aux interfaces et applications." Bordeaux 1, 2001. http://www.theses.fr/2001BOR12444.
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Les dispositifs comportant des géosynthétiques constituent un plan de glissement privilégié lorsqu'ils sont disposés sur les pentes d'ouvrages de génie civil et leur stabilité doit être vérifiée avec soin. Dans ce but, pour améliorer la caractérisation du frottement aux interfaces géosynthétiques et donc le dimensionnement des dispositifs sur pentes, un appareillage de type "plan incliné" a été conçu. De nouvelles procédures d'essais et leurs méthodes d'interprétations associées ont été développées. Elles apportent une nouvelle approche de la caractérisation du frottement aux interfaces et permettent une configuration du plan incliné adaptée à l'application de conditions hydrauliques. Les résultats des essais au plan incliné, et notamment l'influence des conditions hydrauliques sur la stabilité, ont été validés par deux expérimentations en vraie grandeur. Parallèlement à ces expérimentations, nous avons développé un logiciel de calcul de la stabilité des dispositifs géosynthétiques sur pentes. L'utilisation de ces différents outils permet de déterminer l'effort éventuel à reprendre par ancrage en tête de talus. Pour compléter l'étude menée, nous avons étudié le dimensionnement des tranchées d'ancrage en développant un appareillage un banc d'ancrage spécifique et en ayant recours à une modélisation numérique par éléments distincts. A partir d'un travail expérimental important conforté par des applications à des cas réels et une modélisation numérique, la présente recherche apporte de nombreux éléments nouveaux dans l'approche de l'étude de la stabilité des dispositifs géosynthétiques sur pentes.
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Timberlake, Brian D. (Brian Davis). "Free-surface film flow of a suspension and a related concentration instability." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5145.
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Film flow of a suspension has been investigated both experimentally and theoretically. Gravity-driven free-surface inclined plane flow of a suspension of neutrally buoyant particles has been investigated using a stereoscopic particle imaging velocimetry technique. Particles have been shown to migrate away from the solid surface, and the film thickness has been shown to
decrease as the fluid moves down the inclined plane. The free surface has been characterized using a light reflection technique, which shows that surface topography is affected by the inclination angle, and the particle concentration.
This flow has been modeled based on a suspension normal stress approach. A boundary condition at the free surface has been examined, and model predictions have been compared with experimental results. The model predicts that the film thickness, relative to its initial value, will decrease with the bulk particle concentration.
The thin film flow over the inner cylinder in partially filled Couette flow of a suspension has been experimentally investigated as well as modeled. Concentration bands have been shown to form under a variety of different fill fractions, bulk particle concentrations, inclination angles, ratio of inner to outer cylinder, and rotation rates of the inner cylinder. The banding phenomena ranges from a regime where bands are small, mobile and relatively similar in concentration to the bulk, to a regime where
the concentration bands are larger, stationary, and where the space between them is completely devoid of particles.
The role of the film thickness in the band formation process has been investigated, and has led to a model for the band formation process based on a difference in the rate that fluid can drain from height fluctuations relative to the particles.
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Mansour, Rabii. "Contribution a l'étude de l'évaporation en convection naturelle d'un film d'eau ruisselant sur une plaque plane inclinée." Perpignan, 2006. http://www.theses.fr/2006PERP0704.
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L'évaporation par convection naturelle laminaire d'un film d'eau ruisselant sur une paroi plane inclinée soumise à un flux de chaleur uniforme de densité constante est analysée numériquement et expérimentalement. Le couplage des équations qui régissent les transferts dans les deux phases est assuré par la continuité des densités de flux de chaleur et de masse ainsi que par celles des contraintes de cisaillement. Les équations de transferts adimensionnelles sont discrétisées par la méthode des volumes finis et résolues par les algorithmes de Gauss et de Thomas. L'adéquation entre le champ de vitesse et de pression est assurée par l'algorithme SIMPLE. Les épaisseurs des phases liquide et vapeur sont calculées respectivement à partir de l'équation du bilan thermique et massique à l'interface liquide-vapeur par la méthode de la sécante et d'une procédure itérative basée sur la vérification des conditions aux limites avec le milieu ambiant. Les résultats sont présentés sous forme de profils de vitesses, de températures et de concentrations de vapeur d'eau dans les deux phases ainsi que par les nombres de Nusselt et de Sherwood locaux et moyens. Nous analysons l'influence du débit d'eau, de la densité de flux de chaleur et de l'angle d'inclinaison de la plaque sur les épaisseurs des deux phases, les distributions de températures, les vitesses, les concentrations de vapeur d'eau et les valeurs locales et moyennes des nombres de Nusselt et de Sherwood. Les résultats montrent notamment que les transferts de chaleur et de masse ainsi que les épaisseurs des phases liquide et vapeur sont fortement influencés par le débit d'eau, la densité de flux de chaleur et l'angle d'inclinaison de la plaqueThe evaporation by laminar natural convection of a water film streaming along an inclined plane plate and subjected to an uniform and constant heat flux density is performed numerically and experimentally. The linkage between heat and mass transfer in the two phases is ensured by the continuity at the liquid-vapor interface of the heat and mass flux densities and shear stresses. Dimensionless transfers equations are solved by the finite volume method, Gauss and Thomas algorithms. The SIMPLE algorithm assumes the linkage between velocity and pressure fields. The liquid film and the vapor phase thickness are respectively determined by solving the heat and mass balance at the liquid-vapor interface by the secant method and by an iterative procedure to check the ambient conditions. Results are presented as velocity, temperatures, and vapor concentration profiles in the two phases and the local and average Nusselt and Sherwood numbers. The effect of the water flow rate, the heat flux density and the plate inclination on the thickness of the two phases, the temperatures, the velocity, the water vapor concentrations distributions and the local and average Nusselt and Sherwood numbers have been investigated. Results show that the heat and mass transfers and the liquid and vapor phase thicknesses are strongly influenced by the water flow rate, the heat flux density and the plate inclination
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Maier, Marcus R. "Onsets of liquid and gas entrainment during discharge from a stratified air-water region through two horizontal side branches with centerlines falling in an inclined plane." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0003/MQ32176.pdf.
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Beviss-Challinor, Lauren Margaret. "Design, build and test a passive thermal system for a loft : a roof solar chimney application for South African weather conditions." Thesis, Stellenbosch : Stellenbosch University, 2007. http://hdl.handle.net/10019.1/348.
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Thesis (MEng (Mechanical and Mechatronic Engineering))--Stellenbosch University, 2007.ENGLISH: The design, construction and testing of a passive thermal system, a roof solar chimney, for a loft is considered. Unlike conventional solar chimneys the solar collector is constructed from corrugated iron roof sheets with the aim that it can be integrated into existing buildings at a lower cost or used in low cost housing developments. The main objective of the study was to determine the feasibility of such low-cost design to regulate thermal conditions in a loft, that is heating the loft during winter and enhancing natural ventilation during summer, by carrying out an experimental and analytical study. The results obtained from the experimental study showed that for winter the solar chimney, having a channel width, depth and length of 0.7 m, 0.1 m and 1.8 m respectively and with a peal solar radiation of 850 W/m², heated the room air 5°C higher than the ambient temperature during the hottest periods of the day, which is only marginally better than a loft with conventional roof insulation. At night, it was found that reverse airflow occurred through the chimney, cooling the loft down to ambient temperature, due to radiation heat loss from the roof collector to the night sky. For summer operation, the experimental data showed that the chimney was able to maintain the loft at ambient temperature and the analytical study found that the chimney was able to enhance natural ventilation effectively, reaching air exchange rate of 6.6 per hour for the 4.6 m³ volume space. It was also found that the chimney’s performance dropped rapidly and significantly during periods of low solar radiation and at night. A sensitivity analysis illustrated that for both summer and winter operation, the size, tilt angle and absorptivity of the roof collector greatly effected the efficiency and mass flow rates of the system, agreeing well with other literature. These results prove that this low cost solar chimney cooling design was feasible to enhance natural ventilation mainly during hot summer conditions with high solar radiation. Compared to a loft with only conventional roof insulation, the chimney did not perform effectively during the winter to heat the loft up, meaning that winter operation for this specific design is not feasible. Possible improvements to the design include using construction materials with higher thermal capacities to retain heat energy and ensure continued operation during periods of low solar radiation, as well as using selective absorber coatings on the collector surface. It is recommended that further work on the project include the integration of these improvements into the present design and to use the findings obtained from the sensitivity analysis to improve system efficiencies. CFD analysis of the test-rig will be insightful as an additional means to validate and compare with the analytical and experimental data obtained in this report. With the continuation of these studies, this low-cost solar chimney design can be optimised, validated on a commercial scale and built into existing and new housing developments. Incorporating such a passive thermal device will aid homeowners in air regulation and thermal comfort of their living space as well as saving on energy requirements.
Sponsored by the Centre for Renewable and Sustainable Energy Studies, Stellenbosch University
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Zeghmati, Belkacem. "Etude du couplage entre les équations de Luikov et celles de la couche limite laminaire en convection naturelle au-dessus d'une plaque plane inclinée." Perpignan, 1988. http://www.theses.fr/1988PERP0053.
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Etude de l'influence de la teneur en eau initiale du materiau de sa structure, des conditions ambiantes et de l'inclinaison de la plaque sur les transfert de chaleur et de masse dans la couche limite et le materiau poreux non sature
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Ara?jo, Gilmara Linhares Ramos de. "Efeito da inclina??o do plano de terra para antenas de microfita multicamadas com elementos parasitas fractais." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15363.
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Previous issue date: 2011-07-29Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
This work presents the analysis of an antenna of fractal microstrip of Koch with dielectric multilayers and inclinations in the ground plane, whose values of the angles are zero degree (without inclinations), three, seven and twelve degrees. This antenna consists of three dielectric layers arranged vertically on each other, using feeding microstrip line in patch 1, of the first layer, which will feed the remaining patches of the upper layers by electromagnetic coupling. The objective of this work is to analyze the effects caused by increase of the angle of inclination of the ground plane in some antenna parameters such as return loss, resonant frequency, bandwidth and radiation pattern. The presented results demonstrate that with the increase of the inclination angle it is possible to get antennas with characteristics multiband, with bigger bandwidth, and improving the impedance matching for each case analyzed, especially the larger angle
Este trabalho apresenta a an?lise de uma antena de microfita fractal de Koch com multicamadas diel?tricas e inclina??es no plano de terra, cujos valores dos ?ngulos s?o zero grau (sem inclina??es), tr?s, sete e doze graus. Esta antena ? constitu?da por tr?s camadas diel?tricas dispostas verticalmente umas sobre as outras, utilizando alimenta??o por linha de microfita no patch 1, da primeira camada, que ir? alimentar os demais patches das camadas superiores por acoplamento eletromagn?tico. O objetivo deste trabalho ? analisar os efeitos causados pelo aumento do ?ngulo de inclina??o do plano de terra em alguns par?metros da antena, tais como perda de retorno, frequ?ncia de resson?ncia, largura de banda e diagrama de radia??o. Os resultados apresentados demonstram que com o aumento do ?ngulo de inclina??o ? poss?vel obter antenas com caracter?sticas multibanda, com maiores larguras de banda, al?m de melhoramento do casamento de imped?ncias para cada caso analisado, sobretudo os de maior ?ngulo de inclina??o
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Zhu, Kan. "Stabilité non linéaire d’ondes de surface d’un film liquide dévalant un plan incliné et simulation numérique d’ondes interfaciales de deux fluides non miscibles stratifiés." Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10197/document.
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Ce sujet de thèse s'inscrit dans un domaine en plein développement depuis quelques décennies. Il comporte deux parties:La première partie fait suite à une série de travaux théoriques et numériques en écoulement vertical, effectués par Boudlal et Liapidevskii (Boudlal, LML). On considère un film liquide mince non-Newtonien dévalant une paroi plane inclinée. On cherche à construire des solutions d'ondes périodiques avec discontinuités (ODP) d'amplitude finie, et on met en évidence les conditions nécessaires d'existence de ces ODP. On fait une étude à la fois analytique et numérique de la stabilité non linéaire de ce type d'ondes. Les équations modulées pour un trains d'ondes quasi-périodiques avec discontinuités permettent d'aboutir à un critère de stabilité dépendant de deux paramètres (expression intégro-différentielle), difficile à mettre en œuvre pour le tracé des diagrammes de stabilité des ODP, à cause de la présence des singularités aux frontières d'hyperbolicité (amplitudes faibles et maximales). Pour lever ces singularités des formules asymptotiques sont établies. Pour illustrer ces résultats un calcul numérique permet, à l'aide des formules asymptotiques au voisinage des singularités, de présenter des diagrammes de stabilité pour quelques valeurs des paramètres de l’écoulement.La seconde partie de ce travail est dédiée à la simulation numérique de l'écoulement diphasique (gaz/liquide) stratifiés entre deux plans parallèles et inclinés par rapport à l'horizontale. Le comportement de l'interface entre les deux phases fluides est à l'heure actuelle l'un des sous-domaines les plus actifs de la mécanique des fluides numérique. Dans ce contexte, nous avons choisi d'utiliser un code de calcul permettant de résoudre à la fois les équations de Navier-Stokes et les équations constitutives d'un fluide viscoélastique par volumes finis (Gilflow) correspondant à un écoulement monophasique du liquide viscoélastique confiné entre deux parois planes horizontales. J’ai implémenté, avec succès, le modèle diphasique mettant en œuvre la méthode "Volume Of Fluid"(VOF). Le transport de l'interface est résolu à l’aide l'équation de transport de la fonction VOF. Les deux méthodes : Hirt-VOF et PLIC-VOF sont testées pour un écoulement diphasique en régime stratifié instationnaire (gaz/ liquide). Pour illustrer les résultats de la simulation numérique, la configuration (gaz/ liquide) stratifiés est présentéeThis thesis is a part of a growing field in recent decades. It has two parts:The first section follows a series of theoretical and numerical works in vertical flow, made by Boudlal and Liapidevskii (Boudlal., LML). We consider a non-newtonian thin liquid film flowing in down inclined wall. We seek to construct solutions of periodic waves of finite amplitude with discontinuities, the so-called Roll waves (RW), the conditions of existence of these kind of waves are shown. We investigate both analytical and numerical nonlinear stability of these waves.The modulation equations for a quasi-periodic wave trains with discontinuities allow to lead a stability criterion, depending on two parameters (integro-differential expression). The main difficulty to establishthe stability domain is due of the presence of singularities near infinitesimal and maximal amplitudes. To remove these singularities the asymptotic formulas are obtained. To illustrate these results, a numerical calculation, using the asymptotic formulas, allows to pesent the stability diagrams for some values of the flow parameters.The second section of this work is dedicated to the numerical simulation of two-phase flow (gas / liquid) stratified between two parallel planes and inclined relative to the horizontal. The behaviour of the interface between the two phases is, at present, one of the most active sub-areas of computational fluid dynamics. In this context, we have chosen to use a code for solving both the Navier-Stokes equations and the constitutive equations of viscoelastic fluid with finite volumes (Gilflow) corresponding to a single phase flow of viscoelastic fluid confined between two horizontal plane walls. The two-phase flow model was here implemented successfully, by application of the "Volume Of Fluid" method (VOF). The transport of the interface is solved by using the transport equation of the VOF function. Both methods : Hirt-VOF and PLIC-VOF are tested for a two-phase flow in an unsteady stratified flow regime (gas / liquid). To illustrate this numerical simulation, the configuration (gas / liquid) stratified is here presented
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Stella, Francesco. "Caractérisation d’un décollement turbulent sur une rampe : entraînement et lois d’échelle." Thesis, Orléans, 2017. http://www.theses.fr/2017ORLE2043/document.
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Les décollements turbulents massifs sont des phénomènes communs qui peuvent causer des pertes et de nuisances aérodynamiques importantes dans les écoulements industriels, par exemple à l’arrière d’une aile d’avion. Ce travail contribue à leur compréhension par l’analyse phénoménologique d’un décollement turbulent, représentatif d’un grand nombre d’écoulements réels. Le premier objectif est d’identifier les lois d’échelle des décollements turbulents, notamment en rapport avec les caractéristiques de l’écoulement à l’amont de la rampe. Un deuxième objectif est l’analyse, à grande et à petite échelle, des mécanismes de transport de fluide qui pilotent le fonctionnement des décollements. A cet effet, une approche originale est proposée, basée sur une description expérimentale et analytique de la couche cisaillée décollée et des interfaces turbulentes qui la délimitent. Nos résultats suggèrent que les lois d’échelle du décollement varient de façon complexe selon l’interaction de la couche limite à l’amont, de la couche cisaillée et de l’écoulement potentiel extérieur. La taille du décollement est liée à l’intensité de l’entraînement turbulent de masse dans la couche cisaillée, qui à son tour dépend de la turbulence dans la couche limite, bien à l’amont du point de décollement. Cette dépendance pourrait s’appliquer à toute la gamme d’échelles turbulentes responsables du transport de masse. Ces observations montrent clairement le rôle de la couche cisaillée dans le fonctionnement des décollements massifs et suggèrent la faisabilité de stratégies de contrôle nouvelles, de type retro-action ou prédictif, basée sur l’entrainement turbulentMassive turbulent separations are common phenomena that can cause sizeable aerodynamical losses and detrimental effects in industrial flows, for example on airplane wings. This work contributes to their understanding with a phenomenological analysis of a canonical turbulent separation, representative of a large number of real flows. The first objective is to identify the scaling laws of turbulent separations, in particular with respect to their dependencies on the characteristics of the flow upstream of the ramp. A second objective is the analysis, both at large and small scale, of the transfert mechanisms that drive the functioning of separated flows. To this end, a new approach is proposed, centered on the experimental and analytical description of the separated shear layer and of the turbulent interfaces that bound it. Our results suggest that the scaling laws of the separated flow vary in a complex way, in function of the interaction of the incoming boundary layer, the separated shear layer and the free-stream. The size of the separation is related to the intensity of turbulent mass entrainment within the shear layer, which in turn depends on the turbulence in the incoming boundary layer, well upstream of the separation point. This dependency might apply over the entire range of turbulent length scales that are responsible for mass transfer. These observations clearly show the role of the shear layer in the functioning of massive separation. They also suggest the feasibility of new control strategies, both of feedback and feed-forward type, based on turbulent entrainment
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Wang, Yunli. "Etude expérimentale et numérique des oscillations hydrodynamiques en milieux poreux partiellement saturés." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0127/document.
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Cette thèse vise à étudier expérimentalement, analytiquement et numériquement, les conséquences de variations et d'oscillations hydrodynamiques à forte variabilité temporelle en milieux poreux partiellement saturés. Les problèmes que nous étudions comportent des surfaces libres tant à l'extérieur qu'à l'intérieur des milieux poreux, celles-ci étant définies comme des isosurfaces de pression d'eau égale à la pression atmosphérique (Pwater = Patm). Les différentes études expérimentales réalisées en laboratoire sont, respectivement : une expérience d'imbibition dans une boite à sable avec effets capillaires importants; la transmission d'oscillations de la surface libre à travers un massif sableux intercalaire dans un petit canal à houle (IMFT, Toulouse); l'étude de la dynamique et de la propagation des oscillations des niveaux d'eau dans un grand canal à houle (HYDRALAB, Barcelone), partiellement recouvert d'un fond sableux incliné, avec mesures de niveaux d'eau en pleine eau et sous le sable, et mesures du fond sableux (érosion/dépôts). Pour les études théoriques, nous avons développés des solutions analytiques linéarisées. Un exemple de problème traité analytiquement est: l'équation linéarisée de Dupuit-Boussinesq (D-B) transitoire à surface libre, en hypothèse d'écoulements plans et vidange/remplissage instantané : oscillations forcées, transmission et dissipation d'ondes à travers une boite à sable rectangulaire. Nous avons aussi développé une solution de l'équation faiblement non linéaire de Dupuit- Boussinesq (D-B) pour étudier le problème d'imbibition avec variation abrupte du niveau d'eau amont (suivi temporel du front de saturation). Nous avons pu étudier les différents types de problèmes transitoires liés aux expériences citées plus haut par simulation numérique. En particulier, nous avons simulé des écoulements partiellement saturés et insaturés, en coupe verticale, à l'aide d'un code de calcul (BIGFLOW 3D) qui résoud l'équation de Richards généralisée en régime transitoire. Nous avons ainsi étudié numériquement en régime non saturé, l'expérience d'imbibition dans un sable initialement sec à frontières verticales (IMFT sandbox), puis l'expérience de propagation d'ondes dans le grand canal à houle de Barcelone (laboratoire HYDRALAB) comportant une plage de sable inclinée, avec un couplage complètement intégré entre les zones micro-poreuse (sable) et “macro-poreuse” (pleine eau). Pour analyser les résultats de cette dernière expérience et les comparer aux simulations, nous avons utilisé plusieurs méthodes de traitement et d'analyse des signaux : analyse de Fourier (spectres de fréquences) ; ondelettes discrètes multi-résolution (Daubechies) ; analyses corrélatoires simple et croisée. Ces méthodes sont combinées avec des méthodes de préfiltrage pour estimer dérives et résidus (moyennes mobiles ; ondelettes multi-résolution). Cette analyse des signaux a permis de comprendre et quantifier la propagation à travers une plage de sable. Au total, les différentes approches de modélisation mis en oeuvre, associé à des procédures de calage en situation de couplage transitoire non linéaire ont permis de reproduire globalement les phénomènes de propagation de teneur en eau et de niveau d'eau dans les différentes configurations étudiéesThis thesis aims at investigating experimentally, analytically and numerically, the consequences of hydrodynamic variations and oscillations with high temporal variability in partially saturated porous media. The problems investigated in this work involve “free surfaces” both outside and inside the porous media, the free surface being defined as the “atmospheric” water pressure isosurface (Pwater = Patm). The laboratory experiments studied in this work are, respectively: Lateral imbibition in a dry sand box with significant capillary effects; Transmission of oscillations of the free surface through a vertical sand box placed in a small wave canal (IMFT, Toulouse); Dynamics of free surface oscillations and wave propagation in a large wave canal (HYDRALAB, Barcelona), partially covered with sand, with measurements of both open water and groundwater levels, and of sand topography (erosion / deposition). For theoretical studies, we have developed linearized analytical solutions. Here is a sample problem that was treated analytically in this work: The linearized equation of Dupuit-Boussinesq (DB) for transient free surface flow, assuming horizontal flow and instantaneous wetting/drainage of the unsaturated zone: forced oscillations, wave transmission and dissipation through a rectangular sandbox. We also developed a weakly nonlinear solution of the Dupuit-Boussinesq equation to study the sudden imbibition (temporal monitoring of the wetting front). We have studied the different types of transient flow problems related to the experiments cited above by numerical simulation. In particular, we have simulated unsaturated or partially saturated transient flows in vertical cross-section, using a computer code (BIGFLOW 3D) which solves a generalized version of Richards’ equation. Thus, using the Richards / BIGFLOW 3D model, we have studied numerically the experiment of unsaturated imbibition in a dry sand (IMFT sandbox), and then, with the same model, we have also studied the partially saturated wave propagation experiment in the large Barcelona wave canal (HYDRALAB laboratory), focusing on the sloping sandy beach, with coupling between the micro-porous zone (sand) and the “macro-porous” zone (open water). To interpret the results of the latter experiment and compare them to simulations, we use several methods of signal analyzis and signal processing, such as: Fourier analysis, discrete multi-resolution wavelets (Daubechies), auto and cross-correlation functions. These methods are combined with pre-filtering methods to estimate trends and residuals (moving averages; discrete wavelet analyses). This signal analyzis has allowed us to interpret and quantify water propagation phenomena through a sandy beach. To sum up, different modeling approaches, combined with model calibration procedures, were applied to transient nonlinear coupled flow problems. These approaches have allowed us to reproduce globally the water content distributions and water level propagation in the different configurations studied in this work
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Scarfe, Bradley Edward. "Oceanographic Considerations for the Management and Protection of Surfing Breaks." The University of Waikato, 2008. http://hdl.handle.net/10289/2668.
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Although the physical characteristics of surfing breaks are well described in the literature, there is little specific research on surfing and coastal management. Such research is required because coastal engineering has had significant impacts to surfing breaks, both positive and negative. Strategic planning and environmental impact assessment methods, a central tenet of integrated coastal zone management (ICZM), are recommended by this thesis to maximise surfing amenities. The research reported here identifies key oceanographic considerations required for ICZM around surfing breaks including: surfing wave parameters; surfing break components; relationship between surfer skill, surfing manoeuvre type and wave parameters; wind effects on waves; currents; geomorphic surfing break categorisation; beach-state and morphology; and offshore wave transformations. Key coastal activities that can have impacts to surfing breaks are identified. Environmental data types to consider during coastal studies around surfing breaks are presented and geographic information systems (GIS) are used to manage and interpret such information. To monitor surfing breaks, a shallow water multibeam echo sounding system was utilised and a RTK GPS water level correction and hydrographic GIS methodology developed. Including surfing in coastal management requires coastal engineering solutions that incorporate surfing. As an example, the efficacy of the artificial surfing reef (ASR) at Mount Maunganui, New Zealand, was evaluated. GIS, multibeam echo soundings, oceanographic measurements, photography, and wave modelling were all applied to monitor sea floor morphology around the reef. Results showed that the beach-state has more cellular circulation since the reef was installed, and a groin effect on the offshore bar was caused by the structure within the monitoring period, trapping sediment updrift and eroding sediment downdrift. No identifiable shoreline salient was observed. Landward of the reef, a scour hole ~3 times the surface area of the reef has formed. The current literature on ASRs has primarily focused on reef shape and its role in creating surfing waves. However, this study suggests that impacts to the offshore bar, beach-state, scour hole and surf zone hydrodynamics should all be included in future surfing reef designs. More real world reef studies, including ongoing monitoring of existing surfing reefs are required to validate theoretical concepts in the published literature.
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Tseng, Yung-Ling, and 曾詠鈴. "Auto-Calibration of Projections on Inclined Planes and Curved Surfaces Based on the Reversibility Principle of Projected Image." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/93350315402410310339.
Full textAbstract:
碩士國立臺灣科技大學
電機工程系
103
Projection extends much more display possibilities beyond what traditional monitors can offer. However, strict condition requiring the projector directly facing a plane screen needs be satisfied; otherwise, distortion will occur. Distortion occurs in incline plane projection where the projector is not facing in normal direction and more complicated in the cases when the screen is a curved surface. To compensate, a rectified pattern is needed as a pre-processing before an intended image is projected to ensure no distortion. Esisting solutions for the inclined planes involve warp perscpective operation; solutions for curved surfaces are by approximating the curve surface as a collection of small inclined planes or grids, rendering the rectification for curved surface a repetitive rectification process on each of these constituent inclined plane. Alternatively, this study proposes an auto-calibration approach based on the reversibility principle of projection image. To wit, the principle states that, if an image Im from point A is projected to a screen and observed as Im’by point B, then, by reversibility, when Im’is projected from B to the same projection screen, the original image Im will be observed at A. With the original image being a checkboard and A the point of observation and B the position for projection, we are able to calibrate rectification patterns for projections on both inclined planes and curved surfaces. In addition to mathematical support for this approach, this study also presents an auomatic calibration solution that together with projector and camera sertup calibrates rectification patterns for both inclined planes and curved surfaces. The auto-calibration process requires no repetitive matrix manipulations which are prone to numerical errors and ensures no overllaps or gaps among approximated grids. To demonstrate, rectified projections to inclined wall, corner of ceilings, and cylinderal surfaced buck are shown. The technique prsented in this paper can also be extended to applications in interactive virtual reality, as is shown by the demonstration of Wallscape, an interactive viewer dependent wall projection technique.
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Ogden, Kelly Anne. "Flow Down a Wavy Inclined Plane." Thesis, 2011. http://hdl.handle.net/10012/5822.
Full textAbstract:
Under certain conditions, flow down an inclined plane destabilizes and a persistent series of interfacial waves develop. An interest in determining under what conditions a flow becomes unstable and how the interface develops has motivated researchers to derive several models for analyzing this problem.
The first part of this thesis compares three models for flow down a wavy, inclined plane with the goal of determining which best predicts features of the flow. These models are the shallow-water model (SWM), the integral-boundary-layer (IBL) model, and the weighted residual model (WRM). The model predictions for the critical Reynolds number for flow over an even bottom are compared to the theoretical value, and the WRM is found to match the theoretical value exactly. The neutral stability curves predicted by the three models are compared to two sets of experimental data, and again the WRM most closely matches the experimental data. Numerical solutions of the IBL model and the WRM are compared to numerical solutions of the full Navier-Stokes equations; both models compare well, although the WRM matches slightly better. Finally, the critical Reynolds numbers for the IBL model and the WRM for flow over a wavy incline are compared to experimental data. Both models give results close to the data and perform equally well. These comparisons indicate that the WRM most accurately models the flow.
In the second part of the thesis, the WRM is extended to include the effects of bottom heating and permeability. The model is used to predict the effect of heating and permeability on the stability of the flow, and the results are compared to theoretical predictions from the Benney equation and to a perturbation solution of the Orr-Sommerfeld equation from the literature. The results indicate that the model does faithfully predict the theoretical critical Reynolds number with heating and permeability, and both effects destabilize the flow. Finally, numerical simulations of the model equations are compared to full numerical solutions of the Navier-Stokes equations for the case with bottom permeability. The results are found to agree, which indicates that the WRM remains appropriate when permeability is included.
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Mishra, Praveen. "Hydrodynamics of Drop in an Inclined Plane." Thesis, 2016. http://ethesis.nitrkl.ac.in/9214/1/2016_MT_SGhosh.pdf.
Full textAbstract:
A numerical simulation is made on the hydrodynamics of drop over an inclined plane. To track the interface properly, 3D numerical simulation of the drop is made using multiphase Volume of Fluid (VOF) method. The effect of the main influencing parameters like inclination angle, liquid viscosity, surface tension and contact angle on the motion are studied. The numerical results are represented in terms of the phase distribution and velocity vector plots at a different time instant. Variations of the average velocity of the drop with respect to time are also plotted for different cases.
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Foriero, Adolfo. "Pullout capacity of inclined strip anchor plates in sand." Thesis, 1985. http://spectrum.library.concordia.ca/4042/1/ML23160.pdf.
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Lowry-Corry, Angela Emily Rosemary. "Unsteady slender rivulet-flow down an inclined porous plane." Thesis, 2015. http://hdl.handle.net/10539/18518.
Full textAbstract:
A dissertation submitted to the Faculty of Science, University of the Witwatersrand,
Johannesburg, South Africa, in ful lment of the requirements for the degree of Masters of
Science. May 27, 2015.Abstract The unsteady three-dimensional ow of a thin slender rivulet of incompressible Newtonian uid down an inclined porous plane is investigated. The leak-o velocity is not speci ed in the model but is determined in the process of deriving the invariant solution. A second order nonlinear partial di erential equation in two spatial variables and time and containing the leak-o velocity is derived for the height of the thin slender rivulet. Using Lie group analysis it is found that the partial di erential equation can be reduced in two steps to an ordinary di erential equation provided the leak-o velocity satis es a rst order linear partial di erential equation in three variables. An exact analytical solution with a dry patch in the central region is derived for a special leak-o velocity. Two models are considered, one with the leak-o velocity proportional to the height of the rivulet and the other with leak-o velocity proportional to the cube of the height. Numerical solutions are obtained for the height of the rivulet using a shooting method which also determines the two-dimensional boundary of the rivulet on the inclined plane. The e ect of uid leak-o on the height and width of the rivulet is investigated numerically and compared in the two models. The conservation laws for the partial di erential equation with no uid leak-o are investigated. Two conserved vectors are derived, the elementary conserved vector and a new conserved vector. The Lie point symmetry of the partial di erential equation associated with each conserved vector is obtained. Each associated Lie point symmetry is used to perform a double reduction of the partial di erential equation, but the solutions obtained are not physically signi cant.
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Chen, Mei-Lin, and 陳美伶. "Stability of Bingham Fluid Flowing Down Alone an Inclined Plane." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/15545630819771107111.
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Liu, Yu-Yu, and 劉育祐. "Droplets and Bubbles on an Inclined Plane: Contact Angle Hysteresis." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/62999986327855199186.
Full textAbstract:
碩士國立中央大學
化學工程與材料工程研究所
100
Our experiment is to study the phenomenon of contact angle hysteresis by the inclined plate method. Two substrates (PMMA slice and cooper disc) are used. The front (downhill) and rear (uphill) contact angle of the droplet on the inclined substrate is recorded before the critical inclined angle is achieved where the droplet starts to slide down. At part 1, the droplets with different initial states (advancing angle and receding angle) are inclined until it slides away. We also immerse the substrated into water and two initial states of bubbles (advancing angle and receding angle) are operated similarly to the droplets. We can find out that the behavior of droplets and bubbles are alike and the advancing pinning and receding pinning phenomena can be generated based on “induced defect.” At part 2, we use PMMA to make a localized hydrophilic defect on a low hysteresis superhydrophobic surface in order to observe the behavior of adhesion pinning force against gravity force. The variation of droplet volume or defect size with the sliding angle is studied. When droplet slides, the uphill angle of the drop reduces to the receding angle of the defect. The magnitude of sliding angle grows approximately linearly with the pinning length, which is the contact line length on the defect and perpendicular to the sliding direction.
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Chao-Yang, Cheng, and 鄭朝陽. "Ignition of Inclined Porous Plates with Fuel Injection under Natural Convection." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/17803497445428394018.
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Lu, Zheng Xian, and 呂正賢. "Fracture analysis of mixed mode inclined through crack in metallic plates." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/75855283758457518079.
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Chen, Cheng-Yi, and 陳政億. "Analysis Model of Ball End Milling Forces for Inclined Plane Milling." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/fsr3w9.
Full textAbstract:
碩士國立臺北科技大學
製造科技研究所
94
This paper proposes a mechanistic ball end mill cutting force model to estimate the ball end milling forces for inclined plane milling. The developed model that calculates the cutting forces based on a set of cutting force coefficients which depend on the material, the tool, the cutting conditions, the machining directions and the inclined angle of the milling surface. The developed ball end milling force models for inclined plane milling include rise milling ,downhill milling, and horizontal milling. This study uses the present cutting force model and the measured ball end milling forces data to obtain equivalent specific cutting force coefficients (C , C , and C ) for some cutting conditions. By substituting the cutting force coefficients into the present ball end milling force model, the milling force variation both on horizontal plane and inclined plane can be predicted. Finally, the present study also construct some parametric Bezier surfaces of cutting force coefficients in the CAD system by using finite experiment data of ball end milling, which is used to easily find out the cutting force coefficients for any inclined angle of ball end milling operation. In the present study, the cutting force model has been tested on aluminum alloy Al7075-T6 with micro grain carbide ball end mill ( 10 - 2 flutes). Validation tests have been carried out on planar surfaces milling and on inclined plane milling in some typical ball end milling conditions. The results show that the predicted cutting forces agreed well with the measured cutting forces.
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王廷軒. "The Strength of Braided Composite Plates Each with an Inclined Elliptical Hole." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/49941383892006376911.
Full textAbstract:
碩士逢甲大學
機械與電腦輔助工程學系
104
In the work, the Finite Element software —ANSYS— and Point Stress Criterion are used for studying the fracture strength of braided composite plates each with an elliptical hole of inclined angle 45o. First, carbon fiber braid was impregnated with epoxy resin to make braided composite plates by hot-press method. Then, by means of metallographic microscope, we observed the cross-section of a specimen along the direction of fiber yarn weaving, and got the high length ratio and the fiber volume fraction. Furthermore, the Stiffness Averaging Method was adopted to calculate the equivalent engineering moduli of the braided composite plates, and the calculated axial Young’s modulus was then verified by experimental data. Carrying out the tension experiment with the specimens with various major axes (miner radius is fixed) which incline an angle of 45° to the horizontal is to get fracture strength of specimens. Next, the engineering moduli and the resulting fracture strengths of the experimental group are input into ANSYS for analysis to obtain the stress distribution beside the hole in this plate. Meanwhile, the characteristic length from the Point Stress Criterion is derived. Furthermore, the Least-squares method is adopted to set up a functional relationship between characteristic length and major radius. Finally, in order to verify the accuracy of this study, specimens with different radius were made, and the functional relationship mentioned above was used to calculate the characteristic length and the predicted fracture strength. By comparison to experimental data, it is shown that our method can accurately predicted the notched strength of braided composite plates each containing an inclined elliptical hole with a maximum error of only 2.23%.
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Li, Xin–jun, and 李俊鑫. "Slow motion of a dry granular matter down an inclined moving plane." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/32570067250861199023.
Full textAbstract:
碩士國立成功大學
土木工程學系碩博士班
96
In the present study the effect of the variation in porosity in dry granular matters is modeled by using the Wilmanski’s model. To obtain the complete constitutive equations, A thermodynamic analysis,based on the Müller-Liu entropy production principle, is performed to derive the equilibrium expressions of the constitutive variables. Non-equilibrium responses are proposed by means of a quasi-linear theory. The model is subsequently employed to study an isothermal dry granular slow flow down an inclined moving plane, of which the results are compared with the experimental results. It is seen that far dry granular flows with slow to moderate velocities, the Wilmanski’s model is sufficient to describe the effects induced by the variation in porosity, whilst for very rapid flows like avalanche the wilmanski’s model deliver inaccurate predictions of velocity and volume fraction profiles.
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Hsu, Ming-huang, and 許銘晃. "Rapid motion of a dry granular matter down an inclined moving plane." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/37483298859514637475.
Full textAbstract:
碩士國立成功大學
土木工程學系碩博士班
96
Based on the Goodman-Cowin theory we construct a constitutive model for dry granular materials. A thermodynamic analysis, based on the Müller-Liu entropy principle, is performed to derive the equilibrium expressions of the constitutive variables, and non-equilibrium responses are proposed by use of a quasi-linear theory. The model is applied to investigate a steady, isothermal, gravity-driven dry granular flow down an inclined moving plane. Numerical simulations are carried out to study the behavior of the flowing granular materials. Numerical results indicate that the predicted behavior is similar to those observed in the laboratory and field observations. The present model shows a good potential to simulate the behavior of rapid dry granular flows.
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Wen, Chen Jui, and 陳瑞玟. "An Investigation on Children’s Scientific Activity – Inclined Plane Movement as An Example." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/02646426665757850655.
Full textAbstract:
碩士國立臺東大學
幼兒教育學系碩士班
99
This study aims to probe into children’s ability to explore science and their notion and thought when they are engaged in inclined plane movement. I went deeper into how strategies are applied in teaching science in order to improve my pedagogy when I guide children to science. The research subject includes six five-year-old children and the process in inclined plane movement. The data were collected by observation and interview and the result are as follows. First, in the process of inclined plane movement, the frequencies of children’s using ability to explore science from high to low are “experiment”, “communicating”, “observing”, “inferring”, and “predicting”. By posteriori comparisons of the percentage, there is significant difference between “experiment”, “inferring” and “predicting”. Second, as children are engaged in inclined plane movement, they are able to effectively utilize “observing”, “inferring”, “predicting”, “experiment”, and “communicating” to explore science. Third, children have some misconception regarding inclined plane movement. When children are probing into the weight of object which influences the rolling speed on an inclined plane, they think the bigger the object is, the heavier it is and vice versa. Before the experiment, children believe that the lighter the object is, the faster it slides on an inclined plane. Young children understand that the rolling speed on an inclined plane is related to smoothness. They would connect the weight of a cylinder with smoothness and they believe a light cylinder would be smoother. Furthermore, in the children’s opinion, a solid cylinder’s rolls faster than a hollow one because of the wind. They also think that a hollow cylinder rolls slower than a solid one because the wind is inside the hollow cylinder. Fourth, after the inclined plane movement, the young children have understood some scientific facts which are stated as follows. They acquire that the angle of inclination influences object’s rolling speed. On an inclined plane, a curve of sphere and cylinder “roll” while a cuboid, cube, or pyramid “slide” down the plane. The length of diameter of a cylinder does no affect its rolling speed. The smoothness of the plane and cylinder is related to the cylinder’s rolling speed while the weight of the cylinder is not. Fifth, from the inclined plane movement, the researcher has learned self-examination from introspection. Moreover, I comprehend the significance of young children’s science education and acquire confidence in teaching young children science. According to the result above, there are some suggestion proposed for young children’s science teacher and future researcher.
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LIN, CHIEH-SHENG, and 林睫勝. "Research on the Application of Universal Milling Head to Inclined Plane Machining." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/yj3996.
Full textAbstract:
碩士國立虎尾科技大學
機械與電腦輔助工程系碩士班在職專班
107
When using the large gantry type milling machine for processing, the weight and the size of workpiece in need of processing are generally beyond moving and turning. If it is necessary to process beyond the XY plane, such as YZ or ZX, the workpiece will first be moved to a boring machine tool or be directly processed by a five-axis machine tool. However, in reality, although the boring machine tool may solve the problem and saves some expense, it is still difficult in moving the workpiece and there is still an issue of accuracy. On the other hand, despite the five-axis machine tool can solve the accuracy and handling problems, it is relatively more expensive and this can be quite a burden to the manufacturer who only needs fixed axis machining. In the actual case of using a gantry type milling machine for processing, there are three common approaches to inclined plane machining with a three-axis machine tool: 1) the use of a universal head; 2) the use of a indexing plate (rotary table); and 3) horizontal processing of the workpiece, in which they all have strengths and weaknesses. The use of universal head will allow processing of other planes, instead of limiting to the XY plane, for the purpose of better processing. It also has no trouble of clamping long object due to the use of rotary table, and horizontally placed workpiece will not exhibit or collapse due to instability in the center of gravity. Therefore, the use of universal head along with the NX Unigraphics software was suggested for tool path planning in this study. And, based on the principle of coordinate transformation of a non-orthogonal five-axis machine tool, the final coordinate transformation result is derived by use of universal head with X-axis offset. The developed post-processing program using Visual C# and the physical cutting simulation software, VERICUT, would verify the NC program and the cutting model to achieve the goal of simpler processing.
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KALENDAR, ABDULRAHIM. "NUMERICAL AND EXPERIMENTAL STUDIES OF NATURAL CONVECTIVE HEAT TRANSFER FROM VERTICAL AND INCLINED NARROW FLAT PLATES AND SHORT CYLINDERS." Thesis, 2011. http://hdl.handle.net/1974/6863.
Full textAbstract:
Natural convective heat transfer from flat plates and short cylinders inclined at an angle to the vertical in laminar and transition flow regions with isothermal or constant heat flux conditions have been numerically and experimentally studied. When the width of the plate is relatively small compared to its height, i.e., the plate is narrow, the heat transfer rate can be considerably greater than that predicted by these two-dimensional flow results. When the narrow plate is inclined to the vertical, pressure changes normal to the plate surface arise and these pressure changes can alter the nature and the magnitude of the edge effects. When two narrow inclined rectangular flat plates of the same size separated vertically or horizontally, the flow interaction between these heated plates can have a significant effect on the heat transfer.
When relatively small square and circular cylinders with exposed top surfaces inclined to the vertical are used, the interaction of the flow over the surfaces that make up the cylinder and inclination angle have, in general, a considerable effect on the magnitude of the mean heat transfer rate and on the nature of the flow over the cylinder surfaces.
In the present numerical studies it has been assumed that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces, this having been treated using the Boussinesq approach. The numerical solution was obtained by numerically solving the full three-dimensional form of the governing equations, these equations being written in dimensionless form. The solution was obtained using a commercial CFD code, FLUENT. Results were only obtained for a Prandtl number of 0.7; this being approximately the value of air.
In the experimental studies, the average heat transfer rates from cylinders were determined by the transient method, which involves heating the model and then measuring its temperature-time variation while it cools. The average heat transfer rates from the flat plates were determined using a steady state method, which basically involved electrically heating the plate. The tests were carried out inside a large enclosure.Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2011-06-27 19:27:45.724
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Chao, Yung-Cheng, and 趙永正. "Influence of Inclined rupture-plane、groundwater level and fines on the georadar signals." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/52548491304308677704.
Full textAbstract:
碩士國立雲林科技大學
營建工程系碩士班
92
Georadar detection is well known as a technique of non-destructive testing, and also widely adopted by civil engineers in Europe, America and Japan. In Taiwan, this technique has been developed, greatly helping engineers detect subsurface pipelines, pavement, reinforced concrete, pollution and some kinds of waste. Fine soils easily catch or lose electrons, which results in the change of the conductivity of the soil. Therefore, a greater decay of the electromagnetic wave takes place. In this research, a polystyrene-foam board was buried in mixed soil of fixed ratio of weight of both substances to simulate the inclined rupture-plane, so as to find out the change in resolution and dielectric constants. All tests had been done in the laboratory with the same setup. Sand taken from Cho-Shui Creek was used as the medium. Reading was recorded at different depth and distance as the angle of inclined rupture-plane changes in order to study the influence on the reflected radar signals from the soil. The results showed that when a single polystyrene-foam board was buried at the depth of 10 cm with a angle of 30˚, the best signal was read and showed a clear view of the board, depth and direction of dip while the angle cannot be precisely shown. When there were two polystyrene–foam boards buried at the same depth, with same angle and the horizontal spacing was greater than 10 cm, a clear view of two different planes was shown with the directions of dip. However, the angle was not precisely detected yet. For the case that a single polystyrene-form board was buried at the depth of 10 cm with a angle of 30˚, water was added to study the effects of capillary depth and water surface on the radar signals. As soon as the board under the capillary zone, the signal can hardly be detected so that the polystyrene-form board can not be located. The weight of fines which was 12% of the weight of sand were then added to study the effects of fines on the reflected signals. The additive, however, did not cause any obvious change on the signal as a result.
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黃新武. "Waste Water Purification on the Freezing Phenomenon of Falling Film on Inclined Plane." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/11396392904469847308.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
87
As conventional process for treating waste water can not meet the stringent requirement of the environment protection gradually, a more efficient way of treatment is needed. Since the freezing operation of falling film has many advantages, including very high heat and mass transfer, it could possibly offer a more effective and economical method for the issue. The objective of the present study is to perform an experimental investigation on the controlling parameters associated with the freezing phenomenon of falling film, including the flow rate, the inlet temperature, and the inlet concentration of the waste water, the flow rate and the inlet temperature of the refrigerant, the time of ice formation, the inclined angle of the heat transfer plane, and the effect of pre-existing nucleus of crystallization. Optimal running conditions for treating the waste water is to be found. The results of the experimental studies show that the lower the heat transfer rate, the higher the degree of purification. However, degree of purification will decrease when the heat transfer rate is much too low. If the surface of the plate is wetted completely, then reducing the flow rate and inlet temperature of the waste water as far as possible, and increasing the time of ice formation suitably will not only get more quantity of ice formation but also improve the quality of ice formation. With pre-existing nucleus of ice crystal on the surface will result the same trend. Although reduction of the inclined angle of the heat transfer plane has negative effect on the quantity of ice formation, it can improve the degree of purification effectively.
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Chen, Wei-han, and 陳韋翰. "Numerical Study of Water Waves through Submerged Permeability Inclined Thin Plates and Associated Energy Dissipation." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/q8735q.
Full textAbstract:
碩士國立臺灣海洋大學
河海工程學系
105
The interaction between monochromatic incident waves and multiple submerged permeability inclined thin plates has been investigated in the context of two-dimensional linear potential theory. Many types of multiple submerged inclined thin plates have been proposed, including single inclined thin plate, dual vertical arrayed inclined thin plates, double horizontal arrayed inclined thin plates, triple vertical arrayed inclined thin plates, triple horizontal arrayed inclined thin plates and two inclined identical permeable plates that are symmetric with the z-axis. In dual vertical arrayed inclined thin plates, the rear part of the upper plate is fixed at the submergence depth d/h and the lower plate is parallel to the upper plate with the same inclined angle. The porous effect parameter G of the two parallel porous plates with a constant space is the same. The accuracy and validity of the Composite BEM (CBEM) and Multi-domain BEM (MBEM) was determined by comparing the solutions obtained by other researchers employing different method, and excellent agreement has been observed. The performance of the proposed submerged permeability inclined thin plates breakwaters can be significantly observed by selecting optimal design parameters, such as porous effect parameter G, submergence depth d/h, plate width B/h and inclined angle θ. Finally, a series of 2D plots for various parameters are presented to better see the optimal cases.
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Silva, Maria Inês Ferraz. "Utilização de rampas de compósito em tratamentos de ortodontia intercetiva: revisão sistemática." Master's thesis, 2021. http://hdl.handle.net/10284/10727.
Full textAbstract:
A presente revisão sistemática teve como objetivo verificar a eficácia de rampas de compósito no tratamento da mordida cruzada em crianças.
Foi efetuada uma revisão sistemática de artigos científicos em 4 bases de dados, “Pubmed”, “B-on”, “Web Of Science”, “Cochrane Library”, nos idiomas Português, Inglês, Francês e Espanhol, procurando especificar em crianças até aos 13 anos e tendo sido alargados os critérios de inclusão por quantidade insuficiente, o que permitiu encontrar 569 artigos, que após seleção resultou numa inclusão de 34 artigos.
Verifica-se que há uma alta prevalência de má-oclusões em idades pré-escolares e, como tal, é necessário um diagnóstico e tratamento precoce. As rampas de compósito são eficazes no tratamento de mordidas cruzadas anteriores e posteriores funcionais durante a fase de dentição decídua. Sendo um método bastante atrativo pela sua simplicidade técnica, estética, baixo custo, e pode ser feito diretamente em boca no consultório, não requerendo uma fase laboratorial. Por estas razões é também um método atrativo a ser implementado nas unidades de Saúde Pública.The purpose of this work was to check the efficacy of composite ramps in crossbites in childrens. A systematic review of scientific articles was performed in 4 databases, "Pubmed", "B-on", "Web Of Science", "Cochrane Library", in Portuguese, English, French and Spanish, seeking to specify in children up to 13 years and having been extended the inclusion criteria for insufficient quantity, which allowed finding 569 articles, which after selection resulted in an inclusion of 34 articles. It is verified that there is a high prevalence of malocclusions in preschool ages and as such an early diagnosis and treatment is necessary. Composite ramps are effective in the treatment of functional anterior and posterior crossbites during the deciduous dentition. Being a very attractive method due to its simplicity technique, aesthetics, low costs, and can be done in any office. For these reasons it is also an attractive method to be implemented in Public Health units.
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Kaaiye, Sharif Faarah. "A comparative study of DC and AC inclined plane tests on SiR micro-composite insulators." Thesis, 2016. http://hdl.handle.net/10539/20630.
Full textAbstract:
Presently, there is no test on evaluating the tracking and erosion resistance of DC polymeric insulators under contaminated conditions. Often researchers use a modified version of the widely used AC inclined plane test to evaluate the tracking and erosion resistance of DC polymeric insulators. The results obtained from these modified tests thus far have not been conclusive and show various inconsistencies. This research report presents results obtained from an experimental procedure of inclined plane tests of silicone rubber (SiR) insulation at 3.5 kV and 4.5 kV positive DC and AC using intravenous (IV) system as pollutant supply mechanism. The leakage currents were recorded for the duration of each test. In addition, physiochemical tests such as Fourier transform infrared (FTIR) analysis, Thermo-gravimetric analysis (TGA), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were performed on aged and un-aged samples. The findings are that the DC leakage current on the surface tracking activity is bigger (about 2 times) than that under AC for the same equivalent voltages. Furthermore, DC leakage current variations are less random and the average current increases with duration of voltage application compared to AC which doesn’t increase with time. The inclined plane test results of 3.5 kV AC and DC are comparable as deduced from the physiochemical analysis of the test samples. Finally, the failure criteria under DC inclined plane test should only be the leakage current being less than 60 mA and should exclude the tracking length criterion as this would not apply for DC.