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Galvin, Geordie. "Comparison of on-pond measurement and back calculation of odour emission rates from anaerobic piggery lagoons." University of Southern Queensland, Faculty of Engineering and Surveying, 2005. http://eprints.usq.edu.au/archive/00001426/.
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Odours are emitted from numerous sources and can form a natural part of the environment. The sources of odour range from natural to industrial sources and can be perceived by the community dependant upon a number of factors. These factors include frequency, intensity, duration, offensiveness and location (FIDOL). Or in other words how strong an odour is, at what level it becomes detectable, how long it can be smelt for, whether or not the odour is an acceptable or unacceptable smell as judged by the receptor (residents) and where the odour is smelt. Intensive livestock operations cover a wide range of animal production enterprises, with all of these emitting odours. Essentially, intensive livestock in Queensland, and a certain extent Australia, refers to piggeries, feedlots and intensive dairy and poultry operations. Odour emissions from these operations can be a significant concern when the distance to nearby residents is small enough that odour from the operations is detected. The distance to receptors is a concern for intensive livestock operations as it may hamper their ability to develop new sites or expand existing sites. The piggery industry in Australia relies upon anaerobic treatment to treat its liquid wastes. These earthen lagoons treat liquid wastes through degradation via biological activity (Barth 1985; Casey and McGahan 2000). As these lagoons emit up to 80 per cent of the odour from a piggery (Smith et al., 1999), it is imperative for the piggery industry that odour be better quantified. Numerous methods have been adopted throughout the world for the measurement of odour including, trained field sniffers, electronic noses, olfactometry and electronic methods such as gas chromatography. Although these methods all have can be used, olfactometry is currently deemed to be the most appropriate method for accurate and repeatable determination of odour. This is due to the standardisation of olfactometry through the Australian / New Zealand Standard for Dynamic Olfactometry and that olfactometry uses a standardised panel of "sniffers" which tend to give a repeatable indication of odour concentration. This is important as often, electronic measures cannot relate odour back to the human nose, which is the ultimate assessor of odour. The way in which odour emission rates (OERs) from lagoons are determined is subject to debate. Currently the most commonly used methods are direct and indirect methods. Direct methods refer to placing enclosures on the ponds to measure the emissions whereas indirect methods refer to taking downwind samples on or near a pond and calculating an emission rate. Worldwide the odour community is currently divided into two camps that disagree on how to directly measure odour, those who use the UNSW wind tunnel or similar (Jiang et al., 1995; Byler et al., 2004; Hudson and Casey 2002; Heber et al., 2000; Schmidt and Bicudo 2002; Bliss et al., 1995) or the USEPA flux chamber (Gholson et al., 1989; Heber et al., 2000; Feddes et al., 2001; Witherspoon et al., 2002; Schmidt and Bicudo 2002; Gholson et al., 1991; Kienbusch 1986). The majority of peer reviewed literature shows that static chambers such as the USEPA flux chamber under predict emissions (Gao et al., 1998b; Jiang and Kaye 1996) and based on this, the literature recommends wind tunnel type devices as the most appropriate method of determining emissions (Smith and Watts 1994a; Jiang and Kaye 1996; Gao et al., 1998a). Based on these reviews it was decided to compare the indirect STINK model (Smith 1995) with the UNSW wind tunnel to assess the appropriateness of the methods for determining odour emission rates for area sources. The objective of this project was to assess the suitability of the STINK model and UNSW wind tunnel for determining odour emission rates from anaerobic piggery lagoons. In particular determining if the model compared well with UNSW wind tunnel measurements from the same source; the overall efficacy of the model; and the relationship between source footprint and predicted odour emission rate.
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Johannessen, Morten Krøtøy, and Torgeir Myrvold. "Stick-Slip Prevention of Drill Strings Using Nonlinear Model Reduction and Nonlinear Model Predictive Control." Thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9112.
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The main focus of this thesis is aspects in the development of a system for prevention of stick-slip oscillations in drill strings that are used for drilling oil wells. Stick-slip is mainly caused by elasticity of the drill string and changing frictional forces at the bit; static frictional forces are higher than the kinetic frictional forces which make the bit act in a manner where it sticks and then slips, called stick-slip. Stick-slip leads to excessive bit wear, premature tool failures and a poor rate of penetration. A model predictive controller (MPC) should be a suitable remedy for this problem; MPC has gained great success in constrained control problems where tight control is needed. Friction is a highly nonlinear phenomenon and for that reason is it obvious that a nonlinear model is preferred to be used in the MPC to get prime control. Obviously it is of great importance that the internal model used in the MPC is of a certain quality, and as National Oilwell Varco (NOV) has developed a nonlinear drill string model in Simulink, it will be useful to check over this model. This model was therefore verified with a code-to-code comparison and validated using logging data provided from NOV. As the model describing the dynamics of the drill string is somewhat large, a nonlinear model reduction is needed due to the computational complexity of solving a nonlinear model predictive control problem. This nonlinear model reduction is based on the technique of balancing the empirical Gramians, a method that has proven to be successful for a variety of systems. A nonlinear drill string model has been reduced and implemented to a nonlinear model predictive controller (NMPC) and simulated for different scenarios; all proven that NMPC is able to cope with the stick-slip problem. Comparisons have been made with a linear MPC and an existing stick-slip prevention system, SoftSpeed, developed by National Oilwell Varco.
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Rosano-Matchain, Hugo Leonardo. "Decentralised compliant control for hexapod robots : a stick insect based walking model." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/2574.
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This thesis aims to transfer knowledge from insect biology into a hexapod walking robot. The similarity of the robot model to the biological target allows the testing of hypotheses regarding control and behavioural strategies in the insect. Therefore, this thesis supports biorobotic research by demonstrating that robotic implementations are improved by using biological strategies and these models can be used to understand biological systems. Specifically, this thesis addresses two central problems in hexapod walking control: the single leg control mechanism and its control variables; and the different roles of the front, middle and hind legs that allow a decentralised architecture to co-ordinate complex behavioural tasks. To investigate these problems, behavioural studies on insect curve walking were combined with quantitative simulations. Behavioural experiments were designed to explore the control of turns of freely walking stick insects, Carausius morosus, toward a visual target. A program for insect tracking and kinematic analysis of observed motion was developed. The results demonstrate that the front legs are responsible for most of the body trajectory. Nonetheless, to replicate insect walking behaviour it is necessary for all legs to contribute with specific roles. Additionally, statistics on leg stepping show that middle and hind legs continuously influence each other. This cannot be explained by previous models that heavily depend on positive feedback controllers. After careful analysis, it was found that the hind legs could actively rotate the body while the middle legs move to the inside of the curve, tangentially to the body axis. The single leg controller is known to be independent from other legs but still capable of mechanical synchronisation. To explain this behaviour positive feedback controllers have been proposed. This mechanism works for the closed kinematic chain problem, but has complications when implemented in a dynamic model. Furthermore, neurophysiological data indicate that legs always respond to disturbances as a negative feedback controller. Additional experimental data presented herein indicates that legs continuously oppose forces created by other legs. This thesis proposes a model that has a velocity positive feedback control modulated via a subordination variable in cascade with a position negative feedback mechanism as the core controller. This allows legs to oppose external and internal forces without compromising inter-leg collaboration for walking. The single leg controller is implemented using a distributed artificial neural network. This network was trained with a wider range of movement to that so far found in the simulation model. The controller implemented with a plausible biological.
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Hamilton, Tony. "An analogue model for the simulation of earthquake rupture and stick-slip." Thesis, University of Ulster, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326325.
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Bahtui, Ali. "Development of a constitutive model to simulate unbonded flexible riser pipe elements." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/3010.
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The principal objective of this investigation is to develop a constitutive model to simulate the hysteresis behaviour of unbonded flexible risers. A new constitutive model for flexible risers is proposed and a procedure for the identification of the related input parameters is developed using a multi-scale approach. The constitutive model is formulated in the framework of an Euler-Bernoulli beam model, with the addition of suitable pressure terms to the generalised stresses to account for the internal and external pressures, and therefore can be efficiently used for large-scale analyses. The developed non-linear relationship between generalised stresses and strains in the beam is based on the analogy between frictional slipping between different layers of a flexible riser and frictional slipping between micro-planes of a continuum medium in nonassociative elasto-plasticity. Hence, a linear elastic relationship is used for the initial response in which no-slip occurs; an onset-slip function is introduced to define the ‘noslip’ domain, i.e. the set of generalised stresses for which no slip occurs; a nonassociative rule with linear kinematic hardening is used to model the full-slip phase. The results of several numerical simulations for a riser of small-length, obtained with a very detailed (small-scale) non-linear finite-element model, are used to identify the parameters of the constitutive law, bridging in this way the small scale of the detailed finite-element simulations with the large scale of the beam model. The effectiveness of the proposed method is validated by the satisfactory agreement between the results of various detailed finite-element simulations for a short riser, subject to internal and external uniform pressures and cyclic bending and tensile loadings, with those given by the proposed constitutive law. The merit of the present constitutive law lies in the capturing of many important aspects of risers structural response, including the energy dissipation due to frictional slip between layers and the hysteretic response. This privilege allows one to accurately study the cyclic behavior of unbonded flexible risers subject to axial tension, bending moment, internal and external pressures.
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Nguyen, Thi Thu Tra. "Dynamic instabilities of model granular materials." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSET007/document.
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Cette thèse étudie les instabilités dynamiques des milieux granulaires modèles saturés à l’aide d’un appareil triaxial classique. Les instabilités englobent la liquéfaction et les effondrements en compression isotrope drainée, les frottements saccadés en compression triaxiale drainée. Ces instabilités apparaissent spontanément à des contraintes effectives de confinement imprévisibles. Elles sont accompagnées de très rapides et très fortes surpressions interstitielles, malgré un drainage approprié; ce que ne présentent pas les milieux granulaires naturels. En compression isotrope drainée (consolidation), des effondrements locaux naissent instantanément. En compression triaxiale drainée, on observe de larges frottements saccadés quasi-périodiques caractérisés par des déformations volumiques et axiales contractantes. De temps en temps, ces effondrements et frottements saccadés locaux peuvent se développer en liquéfaction menant à une destruction complète de la structure granulaire. Les données à haute résolution temporelle issues de ce travail ont permis la découverte d’une nouvelle famille de liquéfaction dynamique et statique. L’étude des émissions acoustiques passives a permis l’identification de signature spectrale caractéristique. Pour les frottements saccadés, la phase de glissement peut être interprétée comme une consolidation dynamique, limitée par l’unique surface en dessous de la ligne critique de rupture dans le plan des contraintes effectives. La séquence temporelle précise des événements exclut que la pression interstitielle soit la cause principale des instabilités. Cependant, le rôle important de la surpression interstitielle est démontré dans des relations quantitatives entre les incréments de contraintes, et de déformations et l’éphémère surpression interstitielle stabilisée développée pendant la phase de glissement. Cela montre finalement la nature quasi-déterministique de ces instabilités dynamiques. Ces relations empiriques sont basées uniquement sur l’amplitude maximale de l’accélération verticale de très courte durée et sont gouvernées indépendamment par la pression de confinement et par l’indice des vides. La similarité de la surpression interstitielle entre différentes instabilités suggère fortement quelques mécanismes similaires de déclenchement, probablement à partir de ré-arrangements de la micro-structure granulaireThis thesis reports a laboratory study on the dynamic instabilities of model saturated granular material using a triaxial apparatus. The term instability consists of isotropic collapse and liquefaction under isotropic compression and of stick-slip under triaxial compression in drained condition. The instabilities spontaneously occur at unpredictable effective stress with unexpected buildup of excess pore pressure irrespective of fully drained condition, contrasting with the instability-free behaviour of natural granular materials. In isotropic compression, instantaneous local collapse happens and in triaxial compression, very large and quasi-periodic stick-slip occurs with sudden volumetric compaction and axial contraction. Sometimes, these local failures (collapse and stick-slip) can develop into total liquefaction failure, destroying completely the granular structure. High time-resolved data permit the discovery of a new family of dynamic and static liquefaction. Passive acoustic measurements allow the identification of typical spectral signature. For stick-slip phenomenon, the slip phase with constant duration of stress drop can be interpreted as dynamic consolidation at constant deviatoric stress, limited by a unique boundary inside the critical state line in the effective stress plane. The precise temporal sequence of mechanical measurements excludes the generated pore pressure as the main cause of the instabilities. However, the role of pore pressure is emphasised by consistent quantitative relations between the amplitude of incremental stresses, incremental strains and the ephemeral stabilised excess pore pressure developed during the dynamic event, leading to the quasi-deterministic nature of granular instabilities. These empirical relations are based only on the short-lived maximum vertical acceleration and governed separately by the confining pressure and the initial void ratio. The similarity of pore pressure evolution for different kinds of instability strongly suggests some common speculative triggering mechanisms, probably originated from different rearrangements of the granular micro-structure
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Mencl, Stine [Verfasser], and Eberhart [Akademischer Betreuer] Zrenner. "Mechanisms of cone photoreceptor cell death in models for inherited retinal degeneration / Stine Mencl ; Betreuer: Eberhart Zrenner." Tübingen : Universitätsbibliothek Tübingen, 2013. http://d-nb.info/1162843748/34.
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Simon, Joshua Cameron. "Response and Failure of Adhesively Bonded Automotive Composite Structures under Impact Loads." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/34881.
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An experimental technique for conducting low speed impact of adhesively bonded automotive composite joints is presented. Based on the use of a modified drop tower, mode I, II, and mixed mode values for critical energy release rate were determined for a composite/epoxy system and used to create a fracture failure envelope. Because load measurements become erratic and unreliable at higher test rates, displacement-based relationships were used to quantify these energy release rates. Displacement data was collected with an imaging system that utilized edge detection to determine displacement profiles, end displacements, and opening displacements where applicable. Because of the resolution of the image-based approach used, determining crack length experimentally was extremely difficult. As a result, numerical methods were developed to objectively determine the crack length based on the available experimental data in mode I, II, and mixed mode I/II configurations.
This numerical method uses a nonlinear fit to determine mode I crack lengths and a theoretical model based on cubic equations for mode II and mixed-mode I/II, where the coefficients of the equations are determined by using both boundary and transition conditions that are a result of the test setup. A double cantilever beam (DCB) geometry was chosen to collect mode I data, an end-loaded split (ELS) geometry was used for mode II, and a single leg bend (SLB) geometry was used for mixed-mode I/II. These geometries were used to determine the fracture characteristics of adhesively bonded automotive composites to create fracture failure envelopes as well as provide mode I, II, and mixed-mode I/II data to be used in finite element models.
The chosen adhesive exhibited unstable, stick-slip crack growth, which resulted in very few data points being collected from each static DCB specimen as well as drastic drops in energy release rate between initiation and arrest points. Unstable growth also created issues in dynamic testing, as data points surrounding these "stick-slip" events were lost due to the insufficient sampling rate of the available imaging system.
Issues also arose with differences between thick and thin composite adherend specimens. These differences could result from additional curing in thick adherend composite specimens due to the adherends retaining heat. DSC testing was conducted on uncured adhesive using a 2, 5, and 10 minute hold at the cure temperature, and significant additional curing was observed between the two and five minute cures. Due to the difference in relative stiffness between the 12 and 36 ply composite, the local loading rate at the crack tip was lower in the 12 ply adherends, possibly allowing for a larger plastic zone and thus a higher energy release rate. As a result, tests were conducted on 36 ply composite specimens at rates of 1 mm/min and 0.1 mm/min to determine if there were loading rate effects. This testing showed that higher initiation energy relase rates were found at the lower test rate, thus reinforcing the local loading rate theory.
Due to issues with plastic deformation in aluminum adherends, mode II and mixed-mode I/II data were collected using only composite adherends. Only one data point was collected per specimen as the crack propagated directly into the composite after initiating from the precrack, thus multiple tests were conducted to collect sufficient data for constructing a failure envelope.
Once mode I, II and mixed-mode I/II fracture data was collected, a fracture failure envelope was created. This failure envelope, combined with a predetermined factor of safety, could provide some of the necessary tools for design with this adhesive/composite system.Master of Science
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Arcieri, Michael Angel Santos. "Controle de vibrações mecânicas tipo "stick slip" em colunas de perfuração." Pós-Graduação em Engenharia Elétrica, 2013. https://ri.ufs.br/handle/riufs/5011.
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Mechanical vibrations are inevitable in drilling operations. Torsional stick-slip vibrations are vibrations that occur in drilling columns, which are produced by periodic variations of torque and characterized by large fluctuations in the speed of the drill bit. These vibrations are dangerous, primarily by the cyclical characteristic of the phenomenon that by the amplitude of the same, which can cause fatigue of the pipe, failures in the components of the drill string, deformations in the walls of the well, excessive wear of the drill, low rate of penetration, and collapse of the drilling process. The frequency of these unwanted oscillations can be reduced by the application of automatic control techniques. The objective of this study is to evaluate through numerical simulations, the application of conventional control techniques, such as proportional-integral control (PI), and nonlinear, as the sliding mode control (SMC) and the input-output linearization control (IOLC), to eliminate the presence of stick-slip oscillation in drilling columns. The controllers are designed primarily to maintain a constant speed of rotation system, by manipulating engine torque, thereby inferentially control the speed of the drill, thus providing optimum operation conditions, beyond preserving system stability. Results of simulations using drill string torsional models of two degrees of freedom (2-DOF) and four degrees of freedom (4-DOF) show the performance of the proposed control systems, which are analyzed and qualitatively compared.Vibrações mecânicas são inevitáveis nas operações de perfuração. Vibrações torcionais stick-slip são vibrações que ocorrem em colunas de perfuração, as quais são produzidas pelas variações periódicas de torque e caracterizadas por grandes oscilações da velocidade da broca. Estas vibrações são prejudiciais, mais pela característica cíclica do fenômeno que pela amplitude da mesma, podendo originar fadiga da tubulação, falhas nos componentes da coluna de perfuração, deformações nas paredes do poço, desgaste excessivo da broca, baixa taxa de penetração e, inclusive, colapso do processo de perfuração. A frequência destas oscilações indesejadas pode ser reduzida pela aplicação de técnicas de controle automático. O objetivo deste trabalho é avaliar, mediante simulações numéricas, a aplicação de técnicas de controle convencional, como o controle proporcional-integral (PI), e não linear, como o controle por modos deslizantes (SMC) e o controle por linearização entrada-saída (IOLC) para eliminar a presença de oscilações stick-slip em colunas de perfuração. Os controladores são desenvolvidos principalmente para manter constante a velocidade do sistema de rotação, mediante a manipulação do torque do motor, para assim controlar inferencialmente a velocidade da broca, fornecendo desta maneira condições ótimas de operação, além de preservar a estabilidade do sistema. Resultados das simulações, usando modelos torcionais de uma coluna de perfuração de dois graus de liberdade (2-DOF) e de quatro graus de liberdade (4-DOF), mostram o desempenho dos sistemas de controle propostos, os quais são analisados e comparados qualitativamente.
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Lima, Flávio Manuel Póvoa de. "O contexto da pergunta \"O que é direito?\" na teoria analitica contemporânea." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/2/2139/tde-09012014-142339/.
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Nesta dissertação pretendo reler o debate entre Ronald Dworkin e o positivismo jurídico. Farei isto sob o prisma da filosofia analítica, especificamente, contextualizando o debate no âmbito de uma discussão travada entre três teorias semânticas específicas: a descricional, o externalismo semântico e o bi-dimensionalismo ambicioso. Há algum tempo Dworkin lançou uma crítica ao positivismo, qual seja, o positivismo jurídico pretende reduzir a forma direito de como as coisas são à conformação puramente descritiva de como o mundo é. Disse, ainda, que somente quando concebido como uma teoria semântica é que o positivismo jurídico tornar-se-ia inteligível. Os posivistas, a seu turno, argumentam que a Jurisprudência analítica é um projeto teórico pelo direito e não pelo significado do termo direito e que, portanto, deveríamos manter separados dois tipos de questionamentos: O que é direito? e O que é direito?. Se tudo correr bem, ao reler o debate entre os positivistas e Ronald Dworkin a partir do instrumental obtido no âmbito da teoria semântica, poderemos perceber que pode ser verdade que o positivismo jurídico, enquanto projeto teórico, é sobre o direito, o referente, e não sobre o direito, o termo; entretanto, a forma pela qual o positivismo concebe o questionamento O que é direito?, ele mesmo, parece acabar por qualificá-lo, num sentido não trivial, como semântico.I intend to reread the debate between Ronald Dworkin and legal positivism. I will do that through the prism of analytic philosophy, specifically in the context of the debate between three specific semantic theories: descriptional, externalism and the ambitious bidimensionalism. Dworkin criticized legal positivism: the legal positivism aims to reduce the law-way of things to the purely descriptive form of the world. He also said that only when conceived as a semantic theory is that legal positivism would become intelligible. The posivists argue that analytical Jurisprudence is a theoretical project about law and not about the meaning of \"law\", therefore we should keep separated two types of questions: \"What is law?\" and \"What is \'law\'?\". If all goes well, when rereading the debate through the prism of the discussion in the context of semantic theories, we will realize that it may be true that legal positivism is about law, the referent, and not about \"law\". However, the way in which positivism conceives the question \"What is law?\" seems to qualify it as semantic in a nontrivial sense.
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Abdulgalil, Farag. "Commande non linéaire dans les systèmes de forage pétrolier : contribution à la suppression du phénomène de "stick-slip"." Phd thesis, Université Paris Sud - Paris XI, 2006. http://tel.archives-ouvertes.fr/tel-00272937.
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Le travail présenté dans cette thèse porte sur la modélisation et la commande non linéaire le système du forage pétrolier. La problématique principale consiste à proposer un modèle de forage non linéaire et à élaborer un ensemble de stratégies de commande avancées pour améliorer les performances du trépan.A l'heure actuelle, les commandes des systèmes de forage pétroliers sont réalisées à l'aide de régulateurs classiques PI ou PID. Leurs performances se dégradent notablement lors de vibration de torsion causée par le « stick- slip », phénomène qui peut provoquer des couples non linéaires et donc endommager le trépan et le train de tiges. Par conséquent, il est nécessaire de disposer de systèmes de commande plus performants afin de mieux répondre aux exigences et aux performances demandées.
En dépit des diverses lois de commandes linéaires tentatives pour commander ce système mais qui ne garantissent pas la stabilité vis-à-vis des incertitudes. Ceci nous a conduits à proposer une modèle non linéaire en prenant en compte la totalité de l'information du phénomène du stick-slip, ce qui a conduit à une modélisation globale du forage rotary approchant donc au mieux le comportement réel de la plate-forme pétrolière. Pour cela, nous avons suggéré deux approches pour améliorer les performances du système de forage rotary:
• Commande par la technique de linéarisation par bouclage.
• Développement d'une commande par la technique des modes glissant associé à la commande linéarisation par Bouclage.
Comme le système de forage est généralement, est un système soumis aux incertitudes paramétriques, nous avons proposé, de plus, une nouvelle loi de commande non linéaire par Backstepping permettant de mieux améliorer la réponse de la vitesse de rotation du trépan.
Ces trois stratégies de commandes apparaissent la première fois dans ce domaine et la approche de Backsteping s'avère la meilleure. Les résultats de simulations obtenus dans les trois cas sont concluants et la synthèse par Backstepping montré la supériorité de, où la question de robustesse a pu être considérée.
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Hernandez, Erika Lyn. "Parameter Estimation in Linear-Linear Segmented Regression." Diss., CLICK HERE for online access, 2010. http://contentdm.lib.byu.edu/ETD/image/etd3551.pdf.
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Harmouch, Khaled. "Conception et réalisation d’un moteur piézoélectrique pour application automobile haute température." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC007.
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L’objectif de cette thèse est deconcevoir et de réaliser un moteurpiézoélectrique destiné à une application derécupération de chaleur du gaz d’échappement.Cette application nécessite un couplerelativement élevé, une compacité importante,une endurance thermique et un coût acceptable.Afin d’atteindre ce but, la conception du moteurpasse par le choix de son mode defonctionnement. Ce choix est fait en se basantsur des critères comme bas coût, fort couple etcompacité importante.Après la détermination de l’architecture dumoteur piézoélectrique, la modélisation estabordée. Le but du modèle est de calculer lescaractéristiques couple/vitesse connaissantses dimensions et ses matériaux, l’état desurface du contact, la précontrainte et la tensiond’alimentation.La modélisation développée était validée pardes mesures expérimentales.Dans la dernière partie, le moteur dimensionnéest réalisé et testé. Son comportementdynamique et ces caractéristiquescouple/vitesse étaient mesurés. A l’exceptiondu couple à l’arrêt et celui de blocage, toutes lesperformances requises par l’application étaientremplies.Finalement, les résultats de modèle sontcomparés aux mesures faites sur le prototype.Le comportement dynamique était bienreproduit par la modélisation. Néanmoins, uneimprécision du calcul des déplacements dustator était constatée. Cela implique uneimprécision du calcul des caractéristiquesmoteur. Il s’avère que cette imprécision est liéeà l’absence du coefficient d’amortissement decontactThe goal of this thesis is to designand build a piezoelectric motor for an exhaustgas heat recovery application. This applicationrequires relatively high torque, highcompactness, thermal endurance and acceptablecost.In order to achieve this goal, the design of theengine passes by the choice of its mode ofoperation. This choice is made based on criteriasuch as low cost, high torque and compactness.After the determination of the architecture ofthe piezoelectric motor, the modelling isaddressed. The purpose of the model is tocompute the torque/speed characteristicsknowing the motor dimensions and materials,the surface state of the contact, the precompressionforce and the supply voltage.The modeling developed was validated byexperimental measurements.In the last part, the motor is build and tested. Itsdynamic behavior and torque/speedcharacteristics were measured. With theexception of the peak and blocking torque, allthe performances required by the applicationwere fulfilled.Finally, the model results are compared to themeasurements done on the prototype. Thedynamic behavior is well predicted by themodel. However, the model is not able tocompute accurately the stator displacements.This implies inaccuracy in the motorcharacteristics computation. It turns out thatthey are related to the absence of the coefficientof contact damping
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Gandhi, Satish. "Study of Friction Effects on System Dynamics using Low-Order Lumped-Parameter Models." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1029423191.
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Knops, Sascha Alexander [Verfasser], and Silvia [Akademischer Betreuer] Gruhn. "A neuro-mechanical model for the switching of stepping direction and transitions between walking gaits in the stick insect / Sascha Alexander Knops. Gutachter: Silvia Gruhn." Köln : Universitäts- und Stadtbibliothek Köln, 2013. http://d-nb.info/1038485576/34.
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Labes, Stine [Verfasser], Rüdiger [Akademischer Betreuer] Zarnekow, Rüdiger [Gutachter] Zarnekow, and Stefan [Gutachter] Tai. "Towards successful business models of cloud service providers through cooperation-based solutions / Stine Labes ; Gutachter: Rüdiger Zarnekow, Stefan Tai ; Betreuer: Rüdiger Zarnekow." Berlin : Technische Universität Berlin, 2017. http://d-nb.info/1156270219/34.
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Elmaian, Alex. "Méthodologies de simulation des bruits automobiles induits par le frottement." Phd thesis, Université du Maine, 2013. http://tel.archives-ouvertes.fr/tel-00839253.
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Les bruits automobiles induits par le frottement sont à l'origine de nombreuses plaintes clients et occasionnent des coûts de garantie considérables pour les constructeurs automobiles. Les objectifs de la thèse consistent à comprendre la physique à l'origine de ces bruits et proposer des méthodologies de simulation afin de les éradiquer. Un système générique est tout d'abord étudié. Ce système discret met en jeu un contact entre deux masses et une loi de frottement de Coulomb présentant une discontinuité à vitesse relative nulle. Des calculs de valeurs propres complexes de ce système linéarisé autour de sa position d'équilibre glissant sont menés et montrent la présence d'instabilités par flottement voire par divergence. Les simulations temporelles montrent quant à elles que les non-linéarités de contact permettent de stabiliser les niveaux vibratoires en cas d'instabilité selon quatre régimes distincts. De plus, malgré ses trois degrés de liberté, ce système est capable de reproduire les mécanismes de stick-slip, sprag-slip et couplage modal ainsi que les bruits de crissement, grincement et craquement rencontrés sur les systèmes automobiles. Des études paramétriques sont également présentées et mettent en avant des bifurcations de Hopf ainsi que l'effet déstabilisant potentiellement induit par l'amortissement. Des méthodologies permettant de catégoriser les réponses en termes de bruit et de mécanisme sont par la suite proposées. Les occurrences et risques de ces derniers sont alors analysés et des tendances sont dégagées. Enfin, la relation entre les bruits et les mécanismes est établie. L'attention est ensuite portée sur un système automobile particulier. Afin d'étudier son comportement crissant, les analyses de stabilité et les simulations temporelles sont désormais menées sur des modèles éléments-finis. Les simulations temporelles permettent d'observer l'établissement de vibrations auto-entretenues et d'identifier, parmi tous les modes instables prédits lors des analyses de stabilité, celui qui est réellement à l'origine de l'instabilité. L'effet du coefficient de frottement sur les motifs de coalescence et les cycles limites est également investigué. Le risque de crissement est ensuite évalué pour des conditions d'utilisation variées du système. La méthodologie, basée sur des analyses de stabilité, permet de retrouver les principaux constats expérimentaux obtenus sur banc d'essai. Le rôle des géométries et des matériaux constituant le système est également discuté. Enfin, une solution permettant de réduire de façon significative le risque de crissement est proposée.
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Rutter, Brandon Lewis. "Robotic Models of Neuromechanical Step Generation in Insects." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1264794368.
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Thesis (Doctor of Philosophy)--Case Western Reserve University, 2010Department of EMC - Mechanical Engineering Title from PDF (viewed on 2010-05-25) Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
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Twickel, Arndt von [Verfasser], Ansgar [Akademischer Betreuer] Büschges, Silvia [Akademischer Betreuer] Gruhn, and Frank [Akademischer Betreuer] Pasemann. "Embodied Modular Neural Control of Walking in Stick Insects : From Biological Models to Evolutionary Robotics / Arndt von Twickel. Gutachter: Ansgar Büschges ; Silvia Gruhn ; Frank Pasemann." Köln : Universitäts- und Stadtbibliothek Köln, 2012. http://d-nb.info/103817032X/34.
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KONDEPUDI, RAMABALARAJENDRASESH. "NUMERICAL ANALYSIS OF LUMPED PARAMETER DYNAMIC SYSTEMS WITH FRICTION." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1083622496.
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Oberhardt, Tobias. "A micromechanical model for the nonlinearity of microcracks in random distributions and their effect on higher harmonic Rayleigh wave generation." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54365.
Full textAbstract:
This research investigates the modeling of randomly distributed surface-breaking microcracks and their effects on higher harmonic generation in Rayleigh surface waves. The modeling is based on micromechanical considerations of rough surface contact. The nonlinear behavior of a single microcrack is described by a hyperelastic effective stress-strain relationship. Finite element simulations of nonlinear wave propagation in a solid with distributed microcracks are performed. The evolution of fundamental and second harmonic amplitudes along the propagation distance is studied and the acoustic nonlinearity parameter is calculated. The results show that the nonlinearity parameter increases with crack density and root mean square roughness of the crack faces. While, for a dilute concentration of microcracks, the increase in acoustic nonlinearity is proportional to the crack density, this is not valid for higher crack densities, as the microcracks start to interact. Finally, it is shown that odd higher harmonic generation in Rayleigh surface waves due to sliding crack faces introduces a friction nonlinearity.
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Pohlit, David Joseph. "Dynamic Mixed-Mode Fracture of Bonded Composite Joints for Automotive Crashworthiness." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33837.
Full textAbstract:
An experimental evaluation of the mixed-mode fracture behavior of bonded composite joints is presented. Commonly used experimental techniques for characterizing the mode I, mixed-mode I/II, mode II, and mode III fracture behavior have been employed for the purpose of developing a fracture envelope to be utilized in the automotive design process. These techniques make use of such test geometries as the double cantilever beam (DCB), asymmetric double cantilever beam (ADCB), single-leg bend (SLB), end-loaded split (ELS), and split cantilever beam (SCB) specimens. Symmetric versions of the DCB, SLB, and ELS specimens produced mode mixities of 0°, 41°, and 90° respectively, while the testing of ADCB specimens allowed for mode mixities of 18°, 31°.
Pronounced stick-slip behavior was observed for all specimen test geometries under both quasi-static and dynamic loading conditions. Due to the nature of the adhesive studied, a limited number of data points were obtained under mode I loading conditions. A significant increase in the number of measurable crack initiation events was observed for mixed-mode I/II loading conditions, where stick slip behavior was less pronounced. Additionally, a comparison of the measured fracture energies obtained under mixed-mode I/II loading conditions reveals that the addition of a small mode II component results in a decrease in the mode I fracture energy by roughly 50%, as the crack was driven to the interface between the adhesive layer and composite adherends. Furthermore, the propensity of debonds to propagate into the woven composite laminate adherends under mode II loading conditions limited the number of crack initiation points that could be obtained to one or two usable data points per specimen. A limited number of experimental tests using the SCB specimen for mode III fracture characterization, combined with a numerical analysis via finite element analysis, revealed a significant mode II contribution toward the specimen edges. Similarly, FE analyses on full bond width and half bond width SCB specimens was conducted, and results indicate that by inducing a bond width reduction of 50%, the mode II contribution is greatly decreased across the entire width of the specified crack front.
To provide a means for comparison to results obtained using the standard DCB specimen, an alternative driven wedge test specimen geometry was analyzed, as this geometry provided a significant increase in the number of measurable data points under mode I loading conditions. A three-dimensional finite element analysis was conducted to establish ratios of simple beam theory results to those obtained via FEA, GSBT/GFEA, were of particular interest, as these ratios were used to establish correction factors corresponding to specific crack lengths to be used in correcting results obtained from an experimental study utilizing a driven wedge technique. Corrected results show good agreement with results obtained from traditional mode I double cantilever beam tests.
Finally, bulk adhesive experiments were conducted on compact tension specimens to establish a correlation between adhesively bonded composite joint and bulk adhesive fracture behavior under mode I loading conditions. Measured fracture energy values were shown to gradually drop across a range of applied loading rates, similar to the rate-dependent behavior observed with both the DCB and driven wedge specimens. Application of the time-temperature superposition principle was explored to determine whether or not such techniques were suitable for predicting the fracture behavior of the adhesive studied herein. Good correlation was established between the fracture energy values measured and the value of tan d obtained from dynamic mechanical analysis tests conducted at corresponding reduced test rates.Master of Science
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Merli, Gisbert Rafael. "Formulación de un modelo de Mecánica Molecular aplicado al comportamiento estructural de nanotubos de carbono." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/30245.
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Desde su descubrimiento en 1991, los nanotubos de carbono han despertado un gran interés por
parte de la comunidad cientí¿ca e investigadora en todo el mundo. Esto es debido en gran medida
a las excepcionales propiedades mecánicas, térmicas y eléctricas que presentan. Sus extraordinarias
características les con¿eren prometedoras aplicaciones en el campo de la biomecánica, la industria
aeronáutica y la ingeniería. En cualquier caso, la utilización extensiva de estos nuevos materiales en
un futuro próximo pasa necesariamente por la mejora de los actuales procesos de fabricación, hasta
la obtención de nanotubos de una forma económicamente rentable.
Una parte importante de la investigación relacionada con estas singulares moléculas se ha destinado a la predicción de su respuesta tenso-deformacional frente a acciones o estímulos externos. En
algunos casos se han aplicado modelos ya existentes al comportamiento resistente de los nanotubos,
mientras que en otros se han de¿nido nuevos modelos con características propias. Como punto medio
entre los costosos modelos de dinámica molecular y los modelos clásicos derivados de la mecánica
del continuo, aparecen los modelos de mecánica estructural molecular (entre ellos, el stick-spiral),
que permiten describir la estructura atómica del nanotubo a un coste computacional razonable.
Esta tesis doctoral tiene por objeto la formulación general del modelo stick-spiral y su aplicación
a los nanotubos de carbono monocapa. Se ha explorado dicha formulación y sus resultados tanto en
el marco del análisis geométricamente lineal como en el no lineal, además de contrastar las posibles
diferencias en la respuesta estructural de los nanotubos debido a la consideración de dos potenciales
interatómicos (AMBER y Morse).
En la primera parte del trabajo se ha estudiado la indeterminación estática y cinemática del modelo mediante una adaptación de la descomposición en valores singulares de Pellegrino y Calladine
para estructuras articuladas, con el objetivo de averiguar la existencia de soluciones estáticamente
admisibles. Este estudio permite establecer las ecuaciones cinemáticas y estáticas de cada elemento
constituyente del modelo en el rango de la linealidad, así como plantear las características del ensamblaje de las matrices cinemáticas y de equilibrio en el modelo estructural completo. Este primer
análisis ha puesto de mani¿esto la veri¿cación de la relación de contragradiencia para nuestro modelo y permite establecer la determinación cinemática del sistema en función de las condiciones de
contorno presentes, así como la alta indeterminación estática interna que asegura la existencia de
soluciones dada una determinada con¿guración de las cargas externas.
En una segunda etapa se aborda el análisis geométricamente lineal del modelo mediante una
formulación en rigidez completamente general e independiente de la situación de carga mediante la
aplicación sistemática de la ecuación de trabajos virtuales a los elementos estructurales, así como al
sistema completo. Se proporcionan expresiones cerradas para las matrices de rigidez de cada elemento y se demuestra la veri¿cación del ensamblaje booleano en el modelo. Adicionalmente, se presta
especial atención a la curvatura inicial del nanotubo, incluyendo un sistema de esfuerzos iniciales
(preeenergía o pretensado) que tiende a estabilizar la sección transversal y acortar el nanotubo. Como parámetros de contraste, se estiman las características mecánicas del nanotubo como conjunto
bajo los esquemas de carga habituales en piezas alargadas (tracción, compresión, ¿exión y torsión),
lo cual ha permitido validar la formulación comparando resultados con otros autores, como Natsuki y
iEndo; todo ello considerando dos potenciales interatómicos distintos, para averiguar la in¿uencia de
la no linealidad mecánica en la respuesta ¿nal. No obstante, se critica la validez de tales características mecánicas debido a su dependencia de ciertos parámetros geométricos como el espesor de pared
equivalente, de determinación controvertida. Adicionalmente, se describen las ventajas del modelo
de la tesis en relación a la dudosa aplicabilidad de los modelos continuos clásicos y respecto a los
computacionalmente costosos métodos de dinámica molecular.
Posteriormente, se lleva a cabo el análisis del comportamiento de nanotubos frente a la inestabilidad desde un punto de vista geométricamente no lineal. El desarrollo de expresiones simbólicas
para la matriz de rigidez tangente y la demostración del ensamblaje booleano en el caso no lineal
ponen de mani¿esto la potencia de la formulación en la obtención de deformaciones críticas con un
esfuerzo computacional razonable. Desde el punto de vista numérico, se han implementado algoritmos incrementales-iterativos para cada uno de los potenciales interatómicos considerados, de forma
que permitieron veri¿car que la no linealidad geométrica se desencadena previamente a la constitutiva, de acuerdo con Falvo et al. e Iijima et al. Como resultados se proporcionan las trayectorias
de equilibrio no lineales, las deformaciones críticas bajo los esquemas de carga habituales en piezas
alargadas y las geometrías deformadas al ¿nal del proceso de carga.
Finalmente, se estudia la adecuación de la geometría inicial a la proporcionada por el mapeo conforme sobre una super¿cie cilíndrica ideal. En concreto, se determinó el diámetro inicial del cilindro
mediante la minimización de la energía total del sistema para las tres quiralidades, supuestos nulos
los alargamientos de enlace respecto a la longitud de referencia sobre la lámina plana de grafeno. Los
diámetros y esfuerzos obtenidos se contrastaron con los resultados del análisis lineal para el modelo
de la tesis, hallando una íntima coincidencia entre los valores de salida de ambos procedimientos. La
consideración de esta nueva geometría inicial representa una vía alternativa en la introducción de la
curvatura del nanotubo en su comportamiento mecánico.Merli Gisbert, R. (2013). Formulación de un modelo de Mecánica Molecular aplicado al comportamiento estructural de nanotubos de carbono [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/30245
TESIS
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Zimolka, Jakub. "Multi-tensorové zobrazování detailu míchy z dMRI dat s vysokým úhlovým rozlišením." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316839.
Full textAbstract:
The aim of this work was to establish a comprehensive processing pipeline of cervical spinal cord HARDI dMRI data and T2-weighted anatomical MRI images in high-resolution. In the research part we provide description of anatomical data processing, theoretical background of dMRI, description of current approaches to 3D anisotropic diffusion estimation as well as current imaging methods of spinal cord axonal bundles. As one of the first in the world, we are investigating multiple-direction diffusion models for human in-vivo spinal cord white matter minority bundles imaging. We designed our own processing pipeline utilizing Spinal Cord Toolbox (SCT), FSL, in-house developer scripts and TORQUE-based batch system for grid computation, tested on real data from cervical spinal cord area between segments C4-C6 from 26 healthy volunteers. Designed processing pipeline with one non-automatic step, works from pre-processing to parcelation of selected spinal cord structures based on co-registration with anatomical spinal cord template for 25 subjects. One person data includes motion artifacts for which the proces failed. There are visible waves in sagittal images of some subjects caused probably by blood-vessel pulsing. Local quantification metrics of spinal cord anatomy (fractional anisotropy – FA, fractional volumes of first – f1 and second – f2 direction of anisotropic diffusion) from different parts (white matter, gray matter, cortico-spinal tract) and from different population groups (men vs. women), were extracted from dMRI data. As we expected, FA maps show visible decreases in areas of gray matter. We also detected second diffusion dirrection in slices, where the spinal roots come out. In some areas, fractional volume of second diffusion direction reaches up to 40% of the total component of the dMRI signal. All mentioned parameters probability density functions for all mentioned groups are non-normal distributions. Between male and female groups there were no significant distribution differences for f1 and f2 volumes. The distribution of FA values between men and women is statistically different. Unfortunatelly, there is a significant inter-subject variability in results, which has much higher dispersion than differences between different group distributions. Despite the inter-subject variability, this work significantly extends the knowledge about data acquisiton capabilities and MRI and dMRI data from cervical spinal cord image processing. This work also lays down foundations for utilization of the imaging method in future and planned clinical research, where it will be possible to test the alteration of the spinal cord anatomy on the minor secondary bundles separately.
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Motyka, Jakub. "Výpočtové modelování hluku vyzařovaného tramvajovým kolem při průjezdu zatáčkou." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318787.
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This thesis deals with computational modeling of curve squeal noise phenomena which occurs during cornering tight curves by trams. Lateral creep between rail and wheel and slip-stick phenomena leads to self-excited vibrations of the wheel which, therefore, emits unpleasant high-pitched noise. Two FEM models in frequency domain are carried out. First model is based on prestressed modal analysis. Due to unsymmetric stiffness matrix, unstable eigenvalues can occur. It is assumed that self-excited vibrations occurs on frequencies corresponding to that eigenvalues. Second model uses harmonic response analysis. It examines vibrations of the wheel excited by lateral creep force acting in contact region. This force is obtained externally by simple time-domain model. Results from harmonic response are used consequently for noise radiation computation.
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Luxford, Cynthia Joan. "Use of Multiple Representations to Explore Students’ Understandings of Covalent and Ionic Bonding as Measured by the Bonding Representations Inventory." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1366031143.
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Baloche, Valentin. "Contributions négatives et positives de la galectine-9 au développement tumoral : étude dans des modèles tumoraux murins syngéniques In the MB49 Murine Model, Genetic Ablation of Galectin-9 Enhances Anti-Tumor Immune Response: Possible Role of a Greater CXCL9/Il-6 Production Tumor Exosomal Micrornas Thwarting Anti-Tumor Immune Responses in Nasopharyngeal Carcinomas Interferon β and Anti-PD1/PD-L1 Checkpoint Blockade Cooperate in NK Cell-Mediated Killing of Nasopharyngeal Carcinoma Cells Interferon Beta Increases NK Cell Cytotoxicity against Tumor Cells in Patients with Nasopharyngeal Carcinoma via Tumor Necrosis Factor Apoptosis-Inducing Ligand Emerging Therapeutic Targets for Nasopharyngeal Carcinoma: Opportunities and Challenges Galectin-9 Promotes a Suppressive Microenvironment in Human Cancer by Enhancing STING Degradation." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS117.
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Comme les autres galectines, la galectine-9(gal-9) est une lectine animale qui interagit avec un sous-groupe défini de polysaccharides portés par des glycoprotéines ou des glycolipides. La gal-9 associée aux cellules exerce de multiples fonctions dans le cytoplasme, dans le noyau et à la surface de la membrane plasmique. Quelques publications suggèrent que la gal-9 intra-cellulaire inhibe la mobilité des cellules malignes et exerce un effet antimétastatique. En outre la gal-9 peut être sécrétée dans le milieu extra-cellulaire où elle se comporte comme une cytokine avec des effets principalement immunosuppresseurs. Ces effets ont été mis en évidence dans un contexte tumoral chez l’homme et dans des modèles murins. Cependant, on ne disposait pas jusqu’à présent d’un modèle tumoral murin permettant d’évaluer les effets pro-tumoraux ou antitumoraux de la gal-9 indépendamment de la gal-9 des cellules infiltrantes. Pour résoudre ce problème, nous avons dérivé, en employant la technologie CRISPR/Cas9, des clones isogéniques invalidés ou non pour la gal-9 à partir de 2 lignées tumorales murines : CT26 (fond génétique BALB/c) et MB49 (fond génétique C57BL/6). Dans le cas de la lignée MB49, nous avons pu mettre en évidence un phénotype remarquable in vivo. Lors de transplantations itératives, on assiste pour les tumeurs dérivées des clones invalidées à une réduction drastique de la croissance tumorale au bout de 3 ou 4 passages sur les souris syngéniques mais pas sur les souris immunodéficientes. L’émergence de la réponse immunitaire responsable de cet arrêt de la croissance tumorale a été étudiée par immunohistochimie, dosage de cytokines en multiplex dans les extraits tumoraux et analyse du transtriptome par RNAseq. L’augmentation de la production intra-tumorale d’interféron-γ, de CXCL9 et d’Il-6 semble jouer un rôle important dans le renforcement de la réponse immunitaire contre les tumeurs KO-gal-9Like other galectins, galectin-9 (gal-9) is an animal lectin which interacts with a defined subgroup of glycans carried by glycoproteins or glycolipids. Gal-9 associated with cells performs multiple functions in the cytoplasm, in the nucleus and at the surface of the plasma membrane. Some publications suggest that intracellular gal-9 inhibits the mobility of malignant cells and exerts an anti-metastatic effect. In addition, gal-9 can be secreted into the extracellular medium where it behaves like a cytokine with mainly immunosuppressive effects. These effects have been demonstrated in the context of human tumors and in mouse tumor models. However, so far there was no murine tumor model available to assess the pro-tumor or anti-tumor effet of gal-9 independently of gal-9 produced by infiltrating cells. To address this issue, we derived isogenic clones invalidated or not for gal-9 from 2 murine tumoral lines : CT26 (BABL/c genetic background) and MB49 (C57BL/6 genetic background), using CRISPR/Cas9 technology. In the case of the MB49 line, we were able to demonstrate a remarkable phenotype in vivo. During serial transplantations, we saw, for tumors derived from invalidated clones, a dramatic reduction in tumor growth after 3 or 4 passages in syngenic mice but not in immunodeficient mice. The emergence of the immune response responsible for this arrest of tumor growth was investigated by immunohistochemistry, multiplex cytokine assay in tumor extracts and transcriptome analysis by RNAseq. Increased intra-tumor production of interferon-γ, CXCL9 and Il-6 appears to play an important role in enhancing the immune response against KO-gal-9 tumors
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Silva, Paulo Henrique Gonçalves Leonel da. "Controle chaveado de sistemas com incertezas utilizando otimizadores não derivativos /." Ilha Solteira, 2020. http://hdl.handle.net/11449/192112.
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Orientador: Marcelo Carvalho Minhoto TeixeiraResumo: Nesta tese, utiliza-se um otimizador analógico não derivativo proposto por Teixeira & Żak em 1999 como principal ferramenta para os sistemas de controle dos projetos desenvolvidos. Tal otimizador é composto por blocos não lineares e pode ser classificado como um sistema neural artificial. Sistemas chaveados têm grande aplicação prática na otimização de sistemas e são caracterizados por possuírem subsistemas e uma lei de chaveamento que seleciona cada subsistema a cada momento. Deve-se definir condições para que seja possível projetar uma lei de chaveamento que atenda requisitos de projeto. O estudo de técnicas de controle extremal na solução de problemas de busca pelo rastreamento do máximo ponto de potência (do inglês: Maximum Power Point Tracking - MPPT), vem apresentando resultados interessantes na literatura e um tipo de sistema à qual essa técnica pode ser aplicada, é na geração fotovoltaica. Aplica-se o otimizador analógico citado na busca do MPPT de uma célula fotovoltaica, com o objetivo de observar o controle extremal atuando em um processo de otimização, estendendo o controle para quando existem variações de irradiação solar (cenário de uma possível passagem de nuvens). Também observa-se o comportamento do sistema quanto a manter seu correto funcionamento e estabilidade ultimate bounded. A contribuição principal desta tese foi uma nova proposta de utilização conjunta do otimizador de Teixeira & Żak no projeto de controladores ˙ chaveados baseados na minimização da d... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: On this thesis, a non-derivative analog optimizer, proposed by Teixeira & Żak in 1999, was used as the main tool for the proposed control system. Such optimizer is structured by nonlinear blocks and can be classified as an artificial neural system. Switched systems have great theoretical and practical application in systems optimization and are characterized by having subsystems, and a switching law that selects each subsystem at each moment. It is necessary to define conditions so that it is possible to design a switching law for the desired performance of the controlled system. The study of Extremum Seeking Control techniques in the solution of problems of Maximum Power Point Tracking has presented interesting results, and one type of system which this technique can be applied is in the photovoltaic generation. The analog optimizer is applied in the Maximum Power Point Tracking of a photovoltaic cell, with the objective of observing the actuation of the extremal seeking control in an optimization process, extending the control when there are solar irradiation variations (a possible clouds passage scenario). And also observe the behavior of the system and how to maintain its correct functioning and ultimate bounded stability. The main contribution of this thesis was a new procedure for using the mentioned analog optimizer in the design of switched controllers based on the minimization of the derivative of a Lyapunov function. This method allows the relaxed design of controll... (Complete abstract click electronic access below)
Doutor
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Chou, Chi-Feng, and 鄒季峯. "Stick Model Nonlinear History Analysis and Damper Dissipation Evaluation." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/88893712935074527833.
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碩士國立交通大學
土木工程系所
104
Today, elastic structural analysis is conducted for the design of structures without and with dampers in the industry. When earthquakes are small, analysis results may be acceptable. However, when earthquakes are severe enough, structures may exceed elastic limits. Analysis results may not be the same as expected and the design may not be conservative enough. Therefore, nonlinear behavior of structures without and with velocity- and displacement dampers is investigated through time-history analysis in this thesis. Capacity curve is obtained from nonlinear pushover analysis by using ETABS and nonlinear spring for each story is established from the relationship of story shear and inter-story displacement. In the nonlinear pushover analysis, default plastic hinges built in ETABS are adopted. The feasibility of the default plastic hinges is verified by the experimental results provided by the National Center for Research on Earthquake Engineering. Since it is very time-consuming to perform 3D nonlinear structural time-history analysis, the nonlinear structure is simplified to stick model. From the case analysis of a high-rise building, if the structure is assumed to be elastic, displacements are underestimated but absolute accelerations and base shear are overestimated compared with those obtained from nonlinear structural analysis. When velocity- or displacement-dependent dampers are added to the structure, elastic analysis overestimates the effect of dampers because energy dissipated by the structure is ignored. Moreover, the lateral displacement and lateral force demands of the dampers are underestimated. The effectiveness of the dampers cannot be as developed as expected. Therefore, nonlinear analysis is necessary for structures under earthquake loads.
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Li-Nien, Hsu, and 許利年. "Modal Verification and Vibration Characteristics Analysis of Hockey Stick." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/54837593988566948132.
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碩士國立屏東科技大學
機械工程系所
98
This text mainly focuses on the vibration characteristic of hockey stick through the method of the EMA (Experimental Model Analysis) and theoretical FEA (finite element analysis ). First, the theoretical model parameters,including natural frequency, model shape, will be observed by means of the FEA. Second, the theoretical model verification will be compared with the experimental model parameters. Finally, the certificated finite element model could be treated as an analytical model; The Hockey in three types of boundary conditions, i.e.,free-free,free-fixed and free-spring,is also analyzed to compare their modal frequencies and mode shapes. Find spring and freedom,fixing the relationship between the boundary.The modal properties of hockey in grips condition can then be predicted. The proposed analysis and experimental methodology can be beneficial to the design of hockey. The virtual testing can be enhanced in the future.
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吳鴻鈞. "Modal Verification and Vibration Characteristics Analysis of Field Hockey Stick." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/66307833292539369995.
Full textAbstract:
碩士國立屏東科技大學
機械工程系所
98
The purpose of this study is investigate the reverse engineering technique for the reconstruction of the CAD model for field hockey stick. This study first adopts Finite Element Analysis (FEA) and Experimental Modal Analysis (EMA) to perform model verification for field hockey stick. Both FEA and EMA results were compared in order to validate finite element modal. The natural frequencies and mode shapes can be obtained by FEA. Experimental natural frequencies, damping ratios and mode shapes of the field hockey stick can also be obtained by EMA. From the verification between theoretical and practical structural modal testing results. The finite element modal can be treated as an analytical model. Finally, the field hockey stick in two types of boundary conditions, and perform theoretical analysis in order to compare their vibration characteristics and differences, find the relationship between the boundary conditions.
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LIN, YUN, and 林昀. "Auto-pilot Model Car Based on Raspberry Pi Embedded System with Neural Compute Stick using Deep Learning Model." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/deje4w.
Full textAbstract:
碩士國立臺北科技大學
車輛工程系
107
In this study explores Donkey Car as an open source experimental platform for automated radio-controlled cars, based on the Python language, using machine learning and computer vision to drive radio-controlled cars in the Raspberry Pi 3 Model B + for automated cars platform. Through this experimental platform, deep learning is applied to automated radio-controlled cars. Donkey Car is a comprehensive experimental platform that combines a deep learning framework with a Raspberry Pi control board, which is the user first uses the joystick to control the radio-controlled cars in the lane, besides recording the image information and the joystick information. And then inputting the data information into the deep learning framework, which applies the data to train an automated model, includes identifying useful features in the image and making appropriate steering in response to the features, and continuing to collect information, train the model, and test the motion of the radio-controlled cars until the desired result is met. Because of the limited CPU computing power of the Raspberry Pi, this experiment is equipped with Intel neural compute stick to improve the performance of its computing, and use the YOLOv2 target detection to identify obstacles in front of the vehicle to improve autonomous driving application and performance.
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Hong, Hsia Jeng, and 夏正宏. "The Influence of the Friction Models on the Stick-Slip Motion." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/25088777141646266977.
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Yi-ChenHuang and 黃以丞. "Design the Sting Mounting Suboff Model and the Confirmation for the Skill of Resistance Experiment." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/qa844p.
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Liu, Shou-Chi, and 劉少淇. "Development of Micromechanical Stick-slip Model to Characterize the Damping Behaviors of Carbon Nanotube Composites." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/62197687947279012847.
Full textAbstract:
碩士國立交通大學
機械工程學系
100
This research aims to develop a micromechanical stick-slip model to investigate the damping property of carbon nanotube composites. By considering the slip-friction behavior between the CNTs and surround matrix, the energy dissipation mechanism in the composites was characterized in the analytical model. In addition, the effect of aspect ratio of CNTs, interfacial bonding strength, and interfacial friction on the damping behavior of composites were also accounted for in the study. It is noted that the amount of applied cyclic loading on the composites is also an essential factor on the damping behavior, which was also included in the investigation. In addition to the development of micromechanical model, the corresponding finite element analysis was employed to validate the accuracy of the model predictions. A cylindrical FEM model with embedded contract element on the interface between the CNTs and surrounding matrix was created to simulate the contact friction behavior of the CNTs composites. Furthermore, the slip length of the CNTs in the composites in terms of the applied loading was evaluated by comparing the interfacial stress to the interfacial strength through the iteration process. The analytical results and finite element results were then compared with each other. Moreover, the experimental data was also included in the model prediction.
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Lin, Pei-Yu, and 林珮宇. "An Application of Health Belief Model for Nurses’Pevention Behaviors about Needle-Stick Injury, Blood and Body Fluid Exposure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/93076678220339126917.
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碩士國立臺灣大學
護理學研究所
96
The aim of the study was to explore the registered nurses’ health belief about the prevention behaviors of needle-stick injury, blood and body fluid exposure. We used the questionnaires and surveyed nurses working in the five branches of Taipei City Hospital. There were 774 effective questionnaires return, and the response rate was about 57%. The results showed: they were most female nurses, single, got the college or baccalaureate degrees, working about 1-5 years in the hospital, had experienced the needle-stick injuries, blood and body fluid injuries, and had the hepatitis B antibodies. They agreed they would tend to get the blood-borne diseases if they got the needle-stick injuries or blood and body fluid exposures, as well as hurt their beloved families badly. They thought it was good to wear protection equipments and to take protective actions. Besides, they disagreed that time-consuming or less efficient were barriers in wearing the protection equipments. If there were more cues to action, it would push them to take the protective actions. The demographic factors such as gender, age, blood and body fluid exposure experience, and health beliefs,”perceived benefits, perceived barriers and cues to action”, were statistically significant in protective behaviors. The predict factors were “perceived benefits”, and “perceived barriers”, however, they only explained 10% of the variance of the preventive behavior. ”Perceived barriers” is the most influential predictor. It is suggested that further studies examine self-efficacy factor, other than health belief. It is also suggested that intervention strategy to strengthen the preventive behavior. The study was not generalizable to nurses working in other hospitals in Taiwan, but it was useful to provide information in designing the nurses’ training programs about the prevention behaviors of the needle-stick injury, blood and body fluid exposure.
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(7033289), Viraj Dipakbhai Gandhi. "PARAMETRIC DESIGNS AND WEIGHT OPTIMIZATION USING DIRECT AND INDIRECT AERO-STRUCTURE LOAD TRANSFER METHODS." Thesis, 2019.
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Within the aerospace design, analysis and optimization community, there is an increasing demand to finalize the preliminary design phase of the wing as quickly as possible without losing much on accuracy. This includes rapid generation of designs, an early adaption of higher fidelity models and automation in structural analysis of the internal structure of the wing. To perform the structural analysis, the aerodynamic load can be transferred to the wing using many different methods. Generally, for preliminary analysis, indirect load transfer method is used and for detailed analysis, direct load transfer method is used. For the indirect load transfer method, load is discretized using shear-moment-torque (SMT) curve and applied to ribs of the wing. For the direct load transfer method, the load is distributed using one-way Fluid-Structure Interaction (FSI) and applied to the skin of the wing. In this research, structural analysis is performed using both methods and the nodal displacement is compared. Further, to optimize the internal structure, iterative changes are made in the number of structural members. To accommodate these changes in geometry as quickly as possible, the parametric design method is used through Engineering SketchPad (ESP). ESP can also provide attributions the geometric feature and generate multi-fidelity models consistently. ESP can generate the Nastran mesh file (.bdf) with the nodes and the elements grouped according to their geometric attributes. In this research, utilizing the attributions and consistency in multi-fidelity models an API is created between ESP and Nastran to automatize the multi-fidelity structural optimization. This API generates the design with appropriate parameters and mesh file using ESP. Through the attribution in the mesh file, the API works as a pre-processor to apply material properties, boundary condition, and optimization parameters. The API sends the mesh file to Nastran and reads the results file to iterate the number of the structural member in design. The result file is also used to transfer the nodal deformation from lower-order fidelity structural models onto the higher-order ones to have multi-fidelity optimization. Here, static structural optimization on the whole wing serves as lower fidelity model and buckling optimization on each stiffened panel serves as higher fidelity model. To further extend this idea, a parametric model of the whole aircraft is also created.