Modern physics is based on Newton’s laws of motion, which describe interaction via forces. In this paper, we argue that interaction needs to be described in terms of processes. By introducing the momentum work and the associated momentum energy in mechanics, we present a coherent formulation of the process equations for mechanics and thermodynamics. This naturally leads to a simple derivation of the Lorentz-transformed mass, according to which any object changes its mass in real terms when its velocity is changed. Momentum work requires a revision of Newton’s laws of motion. For the first time in the history of physics, the elastic collision between objects, such as particles, can be described as a temporal process, not as interaction via force = counter-force. The mechanism of energy conversion during the elastic collision and other mechanical processes, such as free fall, becomes clear and demonstrates the validity of the principle of energy conservation on microscale at any point in time. The results suggest that physics can be rebuilt on a more coherent footing of dynamic processes up to quantum-process thermodynamics.

This research undertakes the problem of vibration control of vehicular and structural systems using intelligent materials and controllable devices. Advanced modeling tools validated with experimental test data are developed to help with understanding the fundamentals as well as advanced and novel applications of smart and conventional suspension systems. The project can be divided into two major parts. The first part is focused on development of novel smart suspensions using Magneto-Rheological (MR) fluids in unique configurations in order to improve efficiency, controllability, and safety of today's vehicles. In this part of the research, attention is paid to fundamentals as well as advanced applications of MR technology. Extensive rheological studies, both theoretical and experimental, are performed to understand the basic behaviors of MR fluids as complex non-Newtonian fluids in novel applications. Using the knowledge obtained from fundamental studies of MR fluids, unique application concepts are investigated that lead to design, development, and experimental testing of two new classes of smart devices: MR Hybrid Dampers and MR Squeeze Mounts. Multiple generations of these devices are built and tested as proof of concept prototypes. Advanced physics-based mathematical models are developed for these devices. Experimental test data are used to validate the models and great agreement is obtained. The models are used as design tools at preliminary as well as detailed design stages of device development. The significant finding in this part of the research is that MR fluids can deliver a much larger window of controllable force in squeeze mode compared to shear and valve modes which can be used in various applications. The second part of the research is devoted to the development of innovative design tools for suspension design and tuning. Various components of suspension systems are studied and modeled using a new physics-based modeling approach. The component of main interest is the shim stack assembly in hydraulic dampers which is modeled using energy and variational methods. A major finding is that the shims should be modeled individually in order to represent the sliding effects properly when the shim stack is deflected. Next, the individual component models are integrated into a full suspension model. This model is then used as a tool for suspension design, synthesis, and tuning. Using this design tool, suspension engineers in manufacturing companies and other industrial sections can easily perform parametric studies without the need to carry out time consuming and expensive field and laboratory tests. / Ph. D.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第25279号 / 工博第5238号 / 新制||工||1998(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 黒瀬 良一, 教授 長田 孝二, 教授 平山 朋子 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Clinical Psychology / M.A. (Clinical Psychology)

Text in Afrikaans / Die tradisionele Newtoniaanse wetenskapsbeskouing berus op drie basiese aannames, naamlik lineere oorsaaklikheid, reduksionisme en objektiwiteit. Ernstige kritiek word al hoe meer teen hierdie basiese aannames van die Newtoniaanse benadering geopper. Veral vanuit die sistemiese en ekosistemiese benaderings is alternatiewelike denkraamwerke tot hierdie benadering voorgestel. Die mees kontemporere denkraamwerk (epistemologie), naamlik die ekosistemiese benadering, is gebaseer op outonomie, struktuurgedetermineerdheid, attribusie van betekenis en konstruktivisme. Hierdie ekosistemiese beginsels is in hierdie studie gebruik om gevangenisproblematiek (wat tot op hede gekenmerk was deur Newtoniaanse denke) te herkonseptualiseer. Die nuwe konseptualisering is prakties in die psigoterapeutiese proses met gevangenes ge'lllustreer. In hierdie proses is outonomie op drie vlakke (die van gevangene, terapeut en gevangenisstelsel) bevorder. Hierdie konseptualisering skyn dus 'n wetenskaplikverantwoordbare basis te bied waarbinne gevangenisstelsels beskou kan word. / The traditional Newtonian approach to science is based on three fundamental assumtions, namely linear causality, reductionism and objectivity. Serious criticism is increasingly being brought against these fundamental assumptions of the Newtonian approach. Specifically the systemic and ecosystemic approaches have presented alternative ways of thought (epistemology). The mos t contemporary epistemology, namely the ecosystemic approach, is based on autonomy, structure-determinism, attribution of meaning and constructivism. These ecosystemic principles were used in this study to reconceptualize problems associated with prisoners, problems previously approached in a Newtonian way. This new conceptualization was practically illustrated in the psychotherapeutic process with prisoners. In this process autonomy of the prisoner, therapist and the prison system was promoted. This conceptualization present a scientifically justified basis for thinking about correctional systems. / Psychology / M.A. (Sielkunde)

Hollow fiber membranes offer the opportunity to dramatically reduce the energy required to perform gas separations in the chemical industry. The membranes are fabricated from highly non-Newtonian precursor materials, including concentrated polymer solutions that sometimes also contain dispersed particles. These materials are susceptible to shear-induced microstructural changes during processing, which can affect the characteristics of the resulting membrane. This thesis explores several shear-related effects using materials and flow conditions that are relevant for fiber spinning. The findings are discussed as they relate to membrane processing, and also from the standpoint of enhancing our fundamental understanding of the underlying phenomena. First, the effect of shear on polymeric dope solutions was investigated. Shear-induced demixing—a phenomenon not previously studied in membrane materials—was found to occur in membrane dopes. Phase separation experiments also showed that shear-induced demixing promotes macrovoid formation. The demixing process was found to depend not only on the instantaneous shear conditions, but also on the shear history of the solution. This suggests that low-shear flow processes that occur in the upstream tubing and channels used for fiber spinning can affect macrovoid formation. The effect of viscoelastic media on dispersed particles was also explored. Shear-small-angle light scattering results showed that particles suspended in membrane dope solutions formed aggregated, vorticity-oriented structures when shear rates in the shear-thinning regime of the polymer solution were applied. Shear rates well below the shear-thinning regime did not produce any structure. In fact, the application of a Newtonian shear rate to a sample already containing the vorticity structure caused the sample to return to isotropy. Measurements using a highly elastic, constant-viscosity Boger fluid showed that strong normal forces alone are not sufficient to form the vorticity structures, but that shear thinning is also required. Lastly, a study was conducted examining cross-stream migration of particles dispersed in viscoelastic media. Fluids exhibiting varying degrees of shear thinning and normal forces were found to have different effects on the particle distribution along the shear gradient axis in Poiseuille flow. Shear thinning was found to promote migration toward the channel center, while normal stresses tended to cause migration toward the channel walls. In addition to hollow fiber spinning, many other industrially relevant applications involve polymer solutions and suspensions of particles in viscoelastic media. Often, the properties and performance of the material depend strongly on the internal microstructure. The results from the research described in this thesis can be used to guide the design of materials and processing conditions, so that the desired microstructural characteristics can be achieved.

Three dimensional flow regimes are encountered in many types of industrial flow processes such as filtration, mixing, reaction engineering, polymerization and polymer forming as well as environmental systems. Thus, the analyses of phenomena involved fluid flow are of great importance and have been subject of numerous ongoing research projects. The analysis of these important phenomena can be conducted in laboratory through experiments or simply by using the emerging computational fluid dynamics (CFD) techniques. But when dealing with three dimensional fluid flow problems, the complexities encountered make the analysis via the traditional experimental techniques a daunting task. For this reason, researchers often prefer to use the CFD techniques which with some care taken, often produce accurate and stable results while maintaining cost as low as possible. Many CFD codes have been developed and tested in the past decades and the results have been successful and thus encouraging researchers to develop new codes and/or improve existing codes for the solutions of real world problems. In this present project, CFD techniques are used to simulate the fluid flow phenomena of interest by solving the flow governing equations numerically through the use of a personal computer. The aim of this present research is to develop a robust and reliable technique which includes a novel aspect for the solution of three dimensional generalized Newtonian fluids in domains including obstructions, and this must be done bearing in mind that both accuracy and cost efficiency have to be achieved. To this end, the finite element method (FEM) is chosen as the CFD computational method. There are many existing FEM techniques namely the streamline upwind Petrov-Galerkin methods, the streamline diffusion methods, the Taylor-Galerkin methods, among others. But after a thorough analysis of the physical conditions (geometries, governing equations, boundary conditions, assumptions …) of the fluid flow problems to be solve in this project, the appropriate scheme chosen is the UVWP family of the mixed finite element methods. It is scheme originally developed to solve two dimensional fluid flow problems but since the scheme produced accurate and stable results for two dimensional problems, then attempt is made in this present study to develop a new version of the UVWP scheme for the numerical analysis of three dimensional fluid flow problems. But, after some initial results obtained using the developed three dimensional scheme, investigations were made during the course of this study on how to speed up solutions' convergence without affecting the cost efficiency of the scheme. The outcomes of these investigations yield to the development of a novel scheme named the modified three dimensional UVWP scheme. Thus a computer model based on these two numerical schemes (UVWP and the Modified UVWP) is developed, tested, and validated through some benchmark problems, and then the model is used to solve some complicated tests problems in this study. Results obtained are accurate, and stable, moreover, the cost efficiency of the computer model must be mentioned because all the simulations carried out are done using a simple personal computer.

<p>Cilj doktorske disertacije je pobolj&scaron;anje hidrodinamičkih i<br />masenoprenosnih karakteristika airlift reaktora sa<br />spolja&scaron;njom recirkulacijom umetanjem samo-rotirajućih<br />impelera u uzlaznu cev. Uticaj ugradnje samo-rotirajućih<br />impelera na osnovne hidrodinamičke i masenoprenosne<br />osobine ispitivan je pri radu sa različitim tečnostima i<br />distributorima gasa. Rezultati su tumačeni poređenjem<br />vrednosti za sadržaj gasa u uzlaznoj cevi, za brzinu<br />tečnosti u silaznoj cevi, i za zapreminski koeficijent<br />prenosa mase, dobijenih za dve konfiguracije reaktora (sa<br />i bez impelera).<br />Rezultati disertacije ukazuju da ugradnja samo-rotirajućih<br />impelera dovodi do znatnog razbijanja mehurova i<br />smanjenja srednjeg prečnika mehurova gasa, naročito u<br />viskoznim rastvorima karboksimetilceluloze. Prividna<br />brzina gasa, vrsta tečne faze i tip distributora gasa u<br />velikoj meri utiču na efikasnost samo-rotirajućih impelera.<br />Dobijene vrednosti sadržaja gasa u uzlaznoj cevi su do<br />47% veće u konfiguraciji sa impelerima u odnosu na<br />konfiguraciju bez impelera. Iako samo-rotirajući impeleri<br />predstavljaju dodatni otpor proticanju tečnosti, njihovom<br />ugradnjom je u svim ispitivanim sistemima postignuto<br />relativno malo smanjenje brzine tečnosti (oko 10%).<br />Zahvaljujući impelerima, zapreminski koeficijent prenosa<br />mase uvećan je do 82% pri manjim protocima gasa. Pri<br />većim protocima, koji odgovaraju uslovima rada koji se<br />sreću u većini fermentacionih procesa, postignute su oko<br />20-30% veće vrednosti zapreminskog koeficijenta prenosa<br />mase.<br />Pored empirijskih modela, u ovom radu uspe&scaron;no su<br />razvijeni i modeli ve&scaron;tačkih neuronskih mreža kojim se<br />predviđaju sadržaj gasa u uzlaznoj cevi, brzina tečnosti i<br />zapreminski koeficijent prenosa mase za obe konfiguracije<br />airlift reaktora sa spolja&scaron;njom recirkulacijom.</p> / <p>The aim of this study was intensification of<br />hydrodynamic and mass transfer properties of<br />external-loop airlift reactor by means of self-agitated<br />impellers mounted in the riser section. The influence<br />of impellers&rsquo; insertion on the main hydrodynamic<br />and mass transfer characteristics was investigated for<br />various liquid phases and sparger types. The values<br />of riser gas holdup, downcomer liquid velocity and<br />volumetric mass transfer coefficient obtained in<br />configurations with and without impellers were<br />compared.<br />Results showed that the installment of self-agitated<br />impellers led to a significant bubble breakage and<br />decrease of bubble size, especially in viscous<br />carboxymethylcellulose solutions. The efficiency of<br />self-agitated impellers was immensely influenced by<br />superficial gas velocity, liquid phase, and distributor<br />type. Obtained riser gas holdup values were up to<br />47% higher in the configuration with impellers, in<br />comparison to the configuration wthout impellers.<br />Despite the fact that self-agitated impellers<br />represented an obstacle to liquid flow, relatively low<br />reduction of downcomer liquid velocity was attained<br />(about 10%). Furthermore, the insertion of impellers<br />induced up to 82% higher values of volumetric mass<br />transfer coefficient at lower superficial gas velocities.<br />At higher superficial gas velocities, i.e. conditions<br />mainly operated in various fermentation processes,<br />about 20-30% higher values of volumetric mass<br />transfer coefficient were achieved with impellers.<br />In addition to empirical correlations, artificial neural<br />network models were sucessfully developed to<br />predict riser gas holdup, downcomer liquid velocity<br />and volumetric mass transfer coefficient in both<br />external-loop airlift configurations.</p>

La grande diversité des applications, dans tous les domaines industriels, des plus simples aux plus complexes, que ce soit pour un usage quotidienne ou pour des applications high-tech, nécessite la conception continue de systèmes d'étanchéité de plus en plus performants. Les vérins pneumatiques sont des éléments fondamentaux de l'automatisation dans des domaines industriels très variés : les dispositifs de levage, la robotique, l'aérospatial, les systèmes respiratoire, etc. Cependant, un dysfonctionnement d'étanchéité conduit à des performances plus faibles et même à des disfonctionnements. Inversement, une meilleure connaissance des phénomènes aux interfaces, permettra l’amélioration du rendement, la prolongation de la durée de vie et de la fiabilité des différentes applications pneumatiques.Ce travail de thèse est focalisé sur l'étude expérimentale et numérique des systèmes d'étanchéité par joints pneumatiques. Un banc d'essais modulable a été conçu et réalisé pour permettre l'investigation expérimentale de différents types de joints pneumatiques, pour une large gamme de conditions de fonctionnement, en termes de vitesse linéaire, pression pneumatique et solutions constructives. Il permet principalement de caractériser le frottement des joints mais aussi la visualisation des phénomènes physiques au niveau de la zone d'étanchéité et de son environnement.En parallèle, un modèle théorique ElastoHydroDynamique, incluant la prise en compte des conditions de lubrification mixte et le comportement rhéologique non-newtonien de lubrifiant (graisse) a été développé. Il est basé sur le couplage d'un logiciel de calcul non-linéaire (permettant la prise en compte du comportement mécanique hyperélastique des joints) et un modèle d'écoulement en film mince. Les comparaisons de mesures expérimentales avec les prédictions numériques ont permis de valider le modèle théorique ainsi que d'améliorer la compréhension des conditions de fonctionnement et d'alimentation de la zone d'étanchéité. / The great diversity of applications in all industrial fields, from the simplest to the most complex, whether for everyday use or for high-tech applications, requires the continuous design of increasingly efficient sealing systems. Pneumatic cylinders are fundamental elements of automation in a wide variety of industrial fields: lifting devices, robotics, aerospace, respiratory systems, etc. However, a sealing failure leads to lower performance and even malfunctions. Conversely, a better knowledge of the phenomena at the interfaces will allow the improvement of efficiency, the extension of the service life and of the reliability of the various pneumatic applications.This thesis work focuses on the experimental and numerical study of pneumatic seal systems. A modular test bench has been designed and built to allow the experimental investigation of different types of pneumatic seals, for a wide range of operating conditions, in terms of linear velocity, pneumatic pressure and constructive solutions. It mainly allows to characterize the friction of the joints but also the visualization of physical phenomena at the level of the sealing zone and its environment.In parallel, an ElastoHydroDynamic theoretical model, including the consideration of mixed lubrication conditions and the non-Newtonian rheological behaviour of lubricant (grease) has been developed. It is based on the coupling of a non-linear comercial software (allowing the modelling of the hyperelastic mechanical behaviour of the joints) and a thin film flow model. Comparisons of experimental measurements with numerical predictions validated the theoretical model and improved the understanding of the operating and supply conditions of the sealing area.

Orientador : Geraldo de Freitas Maciel. / Banca: Podalyro Amaral de Souza / Banca: Adriano Souza / Resumo: Em função da concentração de material sólido, misturas resultantes de argila e água conferem, via de regra, propriedades não-Newtonianas. Essa concentração passa a variar com a granulometria e a composição do mineral do sedimento, bem como com a qualidade da água. Algumas tentativas foram feitas na busca de melhor explicar a reologia e a dinâmica global dessas misturas nessa última década, notadamente no contexto de lavas torrenciais e misturas hiperconcentradas. Essa dissertação de mestrado tem por objetivo desenvolver uma caracterização reológica de misturas sólido-líquido (água+argila caulinítica e água+areia fina+argila caulinítica) com diferentes concentrações em volume (Cv) para as quais são determinadas, a partir de ensaios de reometria de precisão, as propriedades tais como a viscosidade aparente, tensão crítica de cisalhamento e curva de tensão de cisalhamento x taxa de deformação. Verificou-se, em condições controladas, a influência da temperatura, pH e concentração em volume (Cv) sobre a curva reológica dessas misturas, além de eventuais fenômenos de tixotropia e modo de preparo. O modelo reológico melhor ajustado para as argilas foi o de Herschel-Bulkley ( ( )n τ =τ c + k γ& ), onde: τ é a tensão de cisalhamento; τc é a tensão crítica (ou rigidez inicial); k é um termo de consistência (viscosidade aparente); n é o índice de escoamento; e dy γ& = du é a taxa de deformação. Obtém-se também, a partir de uma análise quantitativa global, leis de evolução dos diversos parâmetros reológicos em função da concentração em volume. Após a etapa de caracterização física e reológica das misturas, realizaram-se, sob condições controladas, ensaios dinâmicos através de escoamentos de lamas em canal inclinado. Nesses ensaios foram medidos os parâmetros lâmina normal, vazões... (Resumo completo, clicar acesso eletrônico abaixo). / According to solid concentration material, clay-water mixture can exhibit non- Newtonian properties. Mixture concentrations vary with the grain size distribution and the composition of the mineral sediment, as well as, with the water quality. In the last decade some attempts were realized to explain the rheology and the global dynamics of those mixtures, mainly in the context of mudflows and high mud concentrated suspensions. The purpose of this work is develop a rheological characterization of solid-liquid mixture (water + clay kaolinitic and water + fine sand + clay kaolinitic) with different solid volume concentrations (Cv) for which are determined, using a R/S Rheometer (Brookfield), rheological properties such as the apparent viscosity, yield stress and shear stress x shear rate curve. It was verified, under controlled conditions, the influence of the temperature, pH and solid volume concentration (Cv) on the rheological curve those mixtures, besides eventual tixotropy phenomenon and way of prepare. The rheological model adjusted for the clays was Herschel-Bulkley ( ( )n τ =τ c + k γ& ), where: τ is shear stress; τc is yield stress; k is a consistency term (apparent viscosity); n is flow index; and dy γ& = du is shear rate. It is also obtained, from a global quantitative analysis, evolution laws of the several rheologics parameters in function of the solid volume concentration. After the stage of rheological and physical characterization of mixing samples, dynamics experiments were made, under controlled conditions, than the flow of mud was observed in the open channel. These analyses were made in order to examine the behavior of parameters such as: normal depth, discharge and velocities. In fact, the experience showed that is possible to deduce wall friction laws from the rheological proprieties based on high mud concentrated suspensions and the dynamic of these muds. / Mestre