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Zeilstra, Christiaan. "Granular dynamics in vibrated beds". Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/57836.
Pełny tekst źródłaHiggins, Anthony. "The dynamics of granular materials". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259539.
Pełny tekst źródłaIsert, Nathan. "Dynamics of levitated granular materials". [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-27683.
Pełny tekst źródłaLaufer, Michael Robert. "Granular Dynamics in Pebble Bed Reactor Cores". Thesis, University of California, Berkeley, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3593891.
Pełny tekst źródłaThis study focused on developing a better understanding of granular dynamics in pebble bed reactor cores through experimental work and computer simulations. The work completed includes analysis of pebble motion data from three scaled experiments based on the annular core of the Pebble Bed Fluoride Salt-Cooled High- Temperature Reactor (PB-FHR). The experiments are accompanied by the development of a new discrete element simulation code, GRECO, which is designed to offer a simple user interface and simplified two-dimensional system that can be used for iterative purposes in the preliminary phases of core design. The results of this study are focused on the PB-FHR, but can easily be extended for gas-cooled reactor designs.
Experimental results are presented for three Pebble Recirculation Experiments (PREX). PREX 2 and 3.0 are conventional gravity-dominated granular systems based on the annular PB-FHR core design for a 900 MWth commercial prototype plant and a 16 MWth test reactor, respectively. Detailed results are presented for the pebble velocity field, mixing at the radial zone interfaces, and pebble residence times. A new Monte Carlo algorithm was developed to study the residence time distributions of pebbles in different radial zones. These dry experiments demonstrated the basic viability of radial pebble zoning in cores with diverging geometry before pebbles reach the active core.
Results are also presented from PREX 3.1, a scaled facility that uses simulant materials to evaluate the impact of coupled fluid drag forces on the granular dynamics in the PB-FHR core. PREX 3.1 was used to collect first of a kind pebble motion data in a multidimensional porous media flow field. Pebble motion data were collected for a range of axial and cross fluid flow configurations where the drag forces range from half the buoyancy force up to ten times greater than the buoyancy force. Detailed analysis is presented for the pebble velocity field, mixing behavior, and residence time distributions for each fluid flow configuration.
The axial flow configurations in PREX 3.1 showed small changes in pebble motion compared to a reference case with no fluid flow and showed similar overall behavior to PREX 3.0. This suggests that dry experiments can be used for core designs with uniform one-dimensional coolant flow early in the design process at greatly reduced cost. Significant differences in pebble residence times were observed in the cross fluid flow configurations, but these were not accompanied by an overall horizontal diffusion bias. Radial zones showed only a small shift in position due to mixing in the diverging region and remained stable in the active core. The results from this study support the overall viability of the annular PB-FHR core by demonstrating consistent granular flow behavior in the presence of complex reflector geometries and multidimensional fluid flow fields.
GRECO simulations were performed for each of the experiments in this study in order to develop a preliminary validation basis and to understand for which applications the code can provide useful analysis. Overall, the GRECO simulation results showed excellent agreement with the gravity-dominated PREX experiments. Local velocity errors were found to be generally within 10-15% of the experimental data. Average radial zone interface positions were predicted within two pebble diameters. GRECO simulations over predicted the amount of mixing around the average radial zone interface position and therefore can be treated as a conservative upper bound when used in neutronics analysis. Residence time distributions from the GRECO velocity data based on the Monte Carlo algorithm closely matched those derived from the experiment velocity statistics. GRECO simulation results for PREX 3.1 with coupled drag forces showed larger errors compared to the experimental data, particularly in the cases with cross fluid flow. The large discrepancies suggest that GRECO results in systems with coupled fluid drag forces cannot be used with high confidence at this point and future development work on coupled pebble and fluid dynamics with multidimensional fluid flow fields is required.
Sanders, Duncan Alexander. "Intruder particle dynamics in vibrated granular beds". Thesis, University of Nottingham, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432036.
Pełny tekst źródłaZheng, Li-Yang. "Granular monolayers : wave dynamics and topological properties". Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1035/document.
Pełny tekst źródłaGranular crystals are spatially periodic structures of elastic particles arranged in crystal lattices. The interactions between particles take place via their elastic interconnections, which are of much smaller dimensions and weights than the beads. This induces propagation of elastic waves in granular structures at significantly slower velocities than in the individual grains. In addition, due to the existence of non-central shear forces, rotations of particles can be initiated, leading to extra phononic modes in the crystals. In the manuscript, wave dynamics in two-dimensional monolayer granular crystals with either out-of-plane or in-plane particle motion is studied. The phononic properties are investigated, including Dirac points, zero-frequency modes, zero-group-velocity modes and their transformation into slow propagating phononic modes. Furthermore, in the presence of edges/boundaries, zero-frequency and extremely slow elastic edge waves can be also predicted in mechanical granular honeycomb crystals (granular graphene). In addition, topological properties of rotational edge waves in a granular graphene are theoretically demonstrated. By inducing topological transition, which turns the topological order of granular graphene from trivial to nontrivial, topological edge transport in the granular graphene can be observed. The developed theories could promote the potential applications of designed granular structures with novel elastic wave propagation properties
Hoomans, Bob Petrus Bernardus. "Granular dynamics of gas-solid two-phase flows". Enschede : University of Twente [Host], 2000. http://doc.utwente.nl/9461.
Pełny tekst źródłaSIGAUD, LUCAS MAURICIO. "STUDIES ON THE DYNAMICS OF DENSE GRANULAR SYSTEMS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=15153@1.
Pełny tekst źródłaMateriais granulares, por sua enorme gama de aplicaçõesindustriais (da indústria alimentícia à astrofísica), vêm sendo cada vez mais estudados durante as últimas duas décadas. No entanto, muito da descrição física inerente ao comportamento deste tipo de material ainda elude os cientistas, tornando este um campo particularmente rico de investigação. Dentre as questões insolutas, estão algumas de crescente interesse, como os mecanismos de fluxo e transporte de grãos, que descrevem fenômenos como a difusão correlacionada e a formação de bandas de cisalhamento, por exemplo. Através de modelos fenomenológicos e matemáticos, este trabalho visa melhorar a compreensão destes fenômenos e dos mecanismos por trás deles, em especial a participação fundamental dos arcos de forças formados pelos grãos. Através de um modelo fenomenológico razoavelmente simples e de simulações computacionais, o papel dos arcos fica evidente ao se observar, nas simulações, o comportamento característico da formação de bandas de cisalhamento, reproduzindo resultados experimentais e previsões de modelos teóricos encontrados na literatura. Concomitantemente, foi desenvolvido um modelo matemático teórico para se descrever a difusão correlacionada de grãos, fenômeno que acreditamos estar baseado no mesmo princípio de transporte através dos arcos, reproduzindo o comportamento qualitativo de simulações computacionais.
Granular materials, due to their huge amount of industrial applications (from food industry to astrophysics), have been the object of an increasing number of studies throughout the last couple of decades. Much of the physical description concerning the behaviour of this kind of material, however, still eludes scientists, turning this field of research into a particularly rich one. Among the unsolved questions in this area there are some of growing interest, such as the mechanisms of grains transport and flux, which describe phenomena like correlated diffusion and the formation of shear bands, for example. By means of phenomenological and mathematical models, this work tries to improve the understanding of these phenomena and the mechanisms behind them, particularly the fundamental role of arches of forces created by the grains. Using a relatively simple phenomenological model and computer simulations, the role of arches becomes evident when it is observed, in the simulations, the characteristic behaviour of shear bands formation, reproducing experimental results and the predictions of theoretical models found in the literature. Simultaneously, a theoretical mathematical model was developed to describe granular correlated diffusion, a phenomenon we believe is based on the same principle of transportation by means of arches, reproducing the qualitative behaviour of computer simulations.
Wang, Da. "Accelerated granular matter simulation". Doctoral thesis, Umeå universitet, Institutionen för fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-110164.
Pełny tekst źródłaThis work has been generously supported by Algoryx Simulation, LKAB (dnr 223-
2442-09), Umeå University and VINNOVA (2014-01901).
Holladay, Seth R. "Optimized Simulation of Granular Materials". BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3856.
Pełny tekst źródłaRenaut, Nathalie. "Granular dynamics simulations of wind-driven, broken ice fields". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23445.
Pełny tekst źródłaSun, Yi. "On efficiency of multibody approach in granular dynamics simulations". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq20898.pdf.
Pełny tekst źródłaRambach, Paul. "Granular chains, an alternative to study confined polymer dynamics". Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLS015.
Pełny tekst źródłaChains dynamics, specially when repulsive interactions come at play, remains an unsolved problem of polymer physics, although understanding this dynamics could improve our knowledge about crucial phenomena at the cellular level. For instance, the transport of RNA across the nuclear pore or the injection of viral DNA plasmid by bacteriophages into a bacteria. Alas, studying repulsive polymers in confined geometries is as experimentally difficult as it is biologically relevant. In spite of recent advances in « nanorheology », from the Brownian motion of local probes, or in computer simulation, designing experiments matching the biological parameters is near impossible. All this leads to unchallenged theoretical tools. Even the straightforward problem of polymer translocation remains lively debated. As a way out of this impasse, we propose to use granular chain as a macroscopic equivalent of a polymer. First we were interested in the internal structure of a stack of granular chains at rest and we rationalized it with polymer analogy. Then we added energy in our experimental system via mechanical excitations which appears to be analogous to the equilibration with a thermal bath. Finally we studied the dynamics of chains in specific confined geometries and compared it to both molecular dynamics simulation and theoretical tools
Gravish, Nicholas Grey. "Collective dynamics of matter with granularity". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47631.
Pełny tekst źródłaCoetzee, C. J. (Cornelis Jacobus). "Forced granular flow". Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51764.
Pełny tekst źródłaENGLISH ABSTRACT: The main goal of the thesis is to validate the ability of discrete element methods (DEM) to predict forced granular flow. Granular flow occurs in a broad spectrum of industrial applications. The thesis focuses on earthmoving processes typical of the mining and agricultural industries. Existing soil mechanics soil-tool models are also investigated and general flow behaviour in and around blades and buckets are established. Soil mechanics theories are used to predict the draft forces on a flat blade moving through granular material. Com and wheat grains are used as material. The rupture (slip) lines in front of the blade are predicted by soil mechanics and compared to experimental results. A two-dimensional test bench is used to visualise the flow of the granular material. Forces and moments that act on the tools are measured. DEM can be used to model industrial granular flow with large displacements. Two types of earthmoving equipment are simulated. The first is a flat blade and the second is a bucket. The forces on these tools are determined using DEM and compared to experimental results. The ability of DEM to predict material compressibility, the flow of material in and around the tools, the rupture lines and the bucket fill rate are investigated. A particle relative displacement method is used to determine the rupture lines.
AFRIKAANSE OPSOMMING: Die hoofdoel van die tesis is om die vermoë van diskrete-element-metodes (DEM) om geforseerde partikelvloei te voorspel, te ondersoek. Partikelvloei word aangetref in 'n breë spektrum van industriële toepassings. Die tesis fokus op grondverskuiwing soos aangetref in myn- en landbouprosesse. Bestaande grondmeganika-modelle word ook ondersoek, asook die algemene gedrag van partikelvloei in en rondom lemme en bakke. Die grondmeganika-modelle word hoofsaaklik gebruik om die kragte op lemme te voorspel. Glip (skuif)-vlakke word ondersoek en vergelyk met eksperimentele resultate. 'n Twee-dimensionele toetsbank word gebruik om die vloei waar te neem. Die kragte en momente op die toerusting word ook gemeet. Mielie- en koringpitte word as materiaal gebruik. DEM kan gebruik word om industriële partikelvloei met groot verplasings te modelleer. Twee tipes toerusting word gesimuleer. Die eerste is 'n plat lem en die tweede 'n bak. Die kragte en momente op dié toerusting word bepaal m.b.V. DEM en dan vergelyk met die eksperimentele resultate. Die vermoë van DEM om materiaalsamedrukking, vloeipatrone, glipvlakke en bakvul-tempo's te voorspel word ondersoek. 'n Partikelrelatiewe- verplasings-metode word gebruik om die glipvlakke te voorspel.
Lun, Cliff Ki Keung. "Kinetic theories of granular flow". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=73989.
Pełny tekst źródłaEstep, Joseph Jeremiah. "Substrate effects from force chain dynamics in dense granular flows". Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39583.
Pełny tekst źródłaCoetzee, Corne J. "The modelling of granular flow using the particle-in-cell method". Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/1334.
Pełny tekst źródłaGranular flow occurs in a broad spectrum of industrial applications that range from separation and mixing in the pharmaceutical industry, to grinding and crushing, blasting, stockpile construction, flow in and from hoppers, silos, bins, and conveyer belts, agriculture, mining and earthmoving. Two totally different approaches of modelling granular flow are the Discrete Element Method (DEM) and continuum methods such as Finite Element Methods (FEM). Continuum methods can be divided into nonpolar or classic continuum methods and polar continuum methods. Large displacements are usually present during granular flow which, without remeshing, cannot be solved with standard finite element methods due to severe mesh distortion. The Particle-in-Cell (PIC) method, which is a so-called meshless method, eliminates this problem since all the state variables are traced by material points moving through a fixed mesh. The main goal of this research was to model the flow of noncohesive granular material in front of flat bulldozer blades and into excavator buckets using a continuum method. A PIC code was developed to model these processes under plane strain conditions. A contact model was used to model Coulomb friction between the material and the bucket/blade. Analytical solutions, published numerical and experimental results were used to validate the contact model and to demonstrate the code’s ability to model large displacements and deformations. The ability of both DEM and PIC to predict the forces acting on the blade and bucket and the material flow patterns were demonstrated. Shear bands that develop during the flow of material were investigated. As part of the PIC analyses, a comparison between classic continuum and polar continuum (Cosserat) results were made. This includes mesh size and orientation dependency, flow patterns and the forces acting on the blade and the bucket. It is concluded that the interaction of buckets and blades with granular materials can successfully be modelled with PIC. In the cases conducted here, the nonpolar continuum was more accurate than the polar continuum, but the polar continuum results were less dependent on the mesh size. The next step would be to apply this technology to solve industrial problems.
Newlon, Scott. "INTRUDER DYNAMICS RESPONSE OF GRANULAR MEDIA WITH NON-LINEAR INTERACTION POTENTIALS". OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2252.
Pełny tekst źródłaHughes, Graeme David. "The dynamical properties of percolating structures". Thesis, Lancaster University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302931.
Pełny tekst źródłaKaddouri, Abdelhamid. "Infinitesimal and finite deformation analysis of saturated granular materials in statics and dynamics". Thesis, Heriot-Watt University, 2001. http://hdl.handle.net/10399/496.
Pełny tekst źródłaVaras, Siriany Germàn. "Air rise through an immersed granular bed : - bulk and surfaces dynamics". Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2011. http://tel.archives-ouvertes.fr/tel-00690436.
Pełny tekst źródłaMeruane, Naranjo Carolina. "Continuum Equations for Studying the Dynamics of Dense Heterogeneous Granular Flows". Tesis, Universidad de Chile, 2010. http://www.repositorio.uchile.cl/handle/2250/102493.
Pełny tekst źródłaPettersson, Thomas. "Analysis and implementation of the Smooth Discrete Element Method in AgX". Thesis, Linköpings universitet, Beräkningsmatematik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-121563.
Pełny tekst źródłaTakagi, Daisuke. "Spreading of viscous fluids and granular materials on slopes". Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/228707.
Pełny tekst źródłaHofmann, Marc [Verfasser], i Jürgen [Akademischer Betreuer] Blum. "Dynamics of Granular Material on Small Bodies / Marc Hofmann ; Betreuer: Jürgen Blum". Braunschweig : Technische Universität Braunschweig, 2014. http://d-nb.info/1175820334/34.
Pełny tekst źródłaMartin, Hugo André Roger. "Convex contact dynamics methods with friction : granular flow and generated elastic waves". Thesis, Université de Paris (2019-....), 2019. https://theses.md.univ-paris-diderot.fr/MARTIN_Hugo_Andre_Roger_va1.pdf.
Pełny tekst źródłaThis work concerns the modeling of dense granular media and their interactions with acoustic phenomena at the laboratory scale.The models that are developed in order to describe the movement of grains can be range into the category of non-smooth discrete methods, often referred to as "contact dynamics". When we consider the friction forces between particles in these models, we obtain constrained optimization problems which are not convex in general. Two convex approaches to the modeling of friction forces in contact dynamics are proposed here.The links between granular flows and the elastic wave propagation are an important topic nowadays. In particular, the acoustic signal emitted by these flows as well as the wave propagation within the medium itself are current research topics. Two studies are proposed here that concerns the relations between granular assembly and generated elastic waves propagation. In particular, a wave propagation model is proposed, whith its variables defined as the infinitesimal perturbations of the grain positions around equilibrium configurations
Montserrat, Michelini Santiago Rafael. "Internal dynamics of gravitational dense granular flows: Experimental study and numerical modeling". Tesis, Universidad de Chile, 2012. http://www.repositorio.uchile.cl/handle/2250/112059.
Pełny tekst źródłaEl estudio de flujos granulares resulta importante en distintas aplicaciones industriales, como también para lograr una mejor comprensión de fenómenos naturales. Los flujos granulares que ocurren en la naturaleza muchas veces presentan un gran poder destructivo. Por ello, la predicción de la ocurrencia y comportamiento de éstos a escalas geofísicas resulta de gran interés para el ordenamiento territorial y evaluación del riesgo en asentamientos humanos y numerosas faenas industriales. Ejemplos de flujos granulares a escalas geofísicas son: flujos detríticos (aluviones), flujos piroclásticos, avalanchas de nieve y avalanchas de roca. Esta tesis está estructurada en base a una serie de artículos de investigación originales autocontenidos en la que se aborda el estudio de la dinámica interna de flujos granulares densos. En el presente trabajo se presenta una serie de resultados experimentales sobre flujos granulares compuestos por mezclas aire-partículas, con diferentes grados de fluidización inicial, inducidos sobre un canal rectangular (experimentos tipo rompimiento de presa ). También se presentan resultados experimentales y numéricos respecto del proceso de defluidización de mezclas aire-partículas en columnas estáticas. Los resultados obtenidos aportan nuevos conocimientos respecto de la física de los flujos granulares densos. Diversos estudios coinciden en que el fluido intersticial, incluso cuando es aire, resulta de gran importancia en la dinámica de los flujos granulares. Las partículas utilizadas en el estudio experimental pertenecen al grupo A según la clasificación del Geldart. Ensayos experimentales han mostrado que mezclas de partículas obtenidas en depósitos de flujos piroclásticos ricos en cenizas presentan un comportamiento del tipo A cuando son sometidas a fluidización por gas. Por ello, los resultados obtenidos en este trabajo tienen especial relevancia para entender la mecánica de flujos piroclásticos densos ricos en cenizas. Además, comportamientos similares a los esperados en mezclas aire-partículas del tipo A han sido observados en mezclas detríticas (agua-partículas) durante procesos de defluidización producto de la autoconsolidación de las mezclas debido a su propio peso. Para llevar acabo esta tesis, en primer lugar se realizaron experimentos tipo rompimiento de presa de mezclas granulares fluidizadas en distintas proporciones. Los resultados obtenidos fueron comparados con flujos derivados de mezclas no fluidizadas y flujos de agua pura, todos ensayados en la misma instalación experimental. La evolución espaciotemporal de la presión de poros en el fondo de los flujos granulares generados y a lo largo del canal experimental fue estudiada mediante un segundo conjunto de experimentos. Técnicas de análisis de imágenes de video permitieron correlacionar la estructura observada del flujo con las señales de presión obtenidas. En particular, con imágenes de video obtenidas a lo largo del canal se estudió los patrones de depositación del flujo. Nuevos experimentos, consistentes en medir la evolución de la presión de poros en mezclas estáticas (columnas) previamente fluidizadas, permitieron estudiar los mecanismos que controlan la difusión de la presión de poros en éstas. Este estudio fue complementado con un modelo numérico capaz de representar de buena forma los resultados experimentales obtenidos. A pesar de que en flujos granulares la difusión de la presión de poros puede ser controlada por otros procesos más complejos que aquellos presentes en el caso estático, este simple experimento aporta nuevas ideas respecto al proceso de difusión de la presión de poros en mezclas inicialmente fluidizadas. Finalmente, se estudió experimentalmente el alcance de los flujos granulares, para todo el rango de fluidización (desde nula a completamente fluidizado) en canales con distintas pendientes. En resumen, nuestros resultados enfatizan la capacidad de la presión de poros en aumentar la movilidad de mezclas fluido-partículas. El incremento en las escalas de tiempo de difusión de la presión de poros debido a la consolidación de mezclas fluidizadas y expandidas causan un notable incremento en el alcance de los flujos, cuando se comparan con mezclas no fluidizadas y no expandidas.
Hedman, Stefan. "Smooth and non-smooth approaches to simulation of granular matter". Thesis, Umeå universitet, Institutionen för fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-50584.
Pełny tekst źródłaKröner, Christian [Verfasser]. "Experimental and numerical description of rapid granular flows and some baseline constraints for simulating 3-dimensional granular flow dynamics / Christian Kröner". Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/105791522X/34.
Pełny tekst źródłaCoetzee, Corné J. "The modelling of granular flow using the particle-in-cell method /". Link to the online version, 2004. http://hdl.handle.net/10019.1/1334.
Pełny tekst źródłaNguyen, Hong Trung. "Coarse-grained Modeling Studies of Polymeric and Granular Systems". Scholar Commons, 2018. http://scholarcommons.usf.edu/etd/7202.
Pełny tekst źródłaCawthorn, Christopher John. "Several applications of a model for dense granular flows". Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/245044.
Pełny tekst źródłaSirmas, Nick. "Dynamics and Stability of Shock Waves in Granular Gases Undergoing Activated Inelastic Collisions". Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36568.
Pełny tekst źródłaTorres, Menéndez Harol [Verfasser], Thorsten [Akademischer Betreuer] Pöschel, Thorsten [Gutachter] Pöschel i Ernesto [Gutachter] Altshuler. "Granular Leidenfrost effect in microgravity and collective dynamics of active granular particles / Harol Torres Menéndez ; Gutachter: Thorsten Pöschel, Ernesto Altshuler ; Betreuer: Thorsten Pöschel". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2021. http://d-nb.info/1228627541/34.
Pełny tekst źródłaStärk, Elmar [Verfasser], Jürgen [Akademischer Betreuer] Horbach i Stefan [Akademischer Betreuer] Egelhaaf. "Dynamics of Granular Matter in Two Dimensions / Elmar Stärk. Gutachter: Jürgen Horbach ; Stefan Egelhaaf". Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2014. http://d-nb.info/1052654274/34.
Pełny tekst źródłaSelvatici, Elena. "Variational formulation for Granular Contact Dynamics simulation via the Alternating Direction Method of Multipliers". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Znajdź pełny tekst źródłaAhnert, Karsten. "Compactons in strongly nonlinear lattices". Phd thesis, Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2010/4853/.
Pełny tekst źródłaIn der hier vorliegenden Arbeit werden Wellenphänomene in stark nichtlinearen Gittern untersucht. Diese Gitter zeichnen sich vor allem durch die Abwesenheit von klassischen linearen Wellen aus. Es wird gezeigt, dass Kompaktonen – stark lokalisierte solitäre Wellen, mit Ausläufern welche schneller als exponentiell abfallen – existieren, und dass sie eine entscheidende Rolle in der Dynamik dieser Gitter spielen. Kompaktonen treten in verschiedenen diskreten physikalischen Systemen auf. Ein Teil der Arbeit behandelt dabei Gitter von dispersiv gekoppelten Oszillatoren, welche beispielsweise Anwendung in gekoppelten Josephsonkontakten oder gekoppelten Ginzburg-Landau-Gleichungen finden. Ein weiterer Teil beschäftigt sich mit Hamiltongittern, wobei die granulare Kette das bekannteste Beispiel ist, in dem Kompaktonen beobachtet werden können. Im dritten Teil werden Systeme, welche im Zusammenhang mit der Diskreten Nichtlinearen Schrödingergleichung stehen, studiert. Diese Gleichung beschreibt beispielsweise Arrays von optischen Wellenleitern oder die Dynamik von Bose-Einstein-Kondensaten in optischen Gittern. Das Studium der Kompaktonen basiert hier hauptsächlich auf dem numerischen Lösen der dazugehörigen Wellengleichung. Dies mündet in einer quasi-exakten Lösung, dem Kompakton, welches bis auf numerische Fehler genau bestimmt werden kann. Ein anderer Ansatz, der in dieser Arbeit mehrfach verwendet wird, ist die Approximation des Gitters durch ein kontinuierliches Medium. Die daraus resultierenden Kompaktonen besitzen einen im mathematischen Sinne kompakten Definitionsbereich. Beide Methoden liefern qualitativ und quantitativ gut übereinstimmende Ergebnisse. Zusätzlich werden die dynamischen Eigenschaften von Kompaktonen mit Hilfe von direkten numerischen Simulationen der Gittergleichungen untersucht. Dabei wird ein Hauptaugenmerk auf die Entstehung von Kompaktonen unter physikalisch realisierbaren Anfangsbedingungen und ihre Kollisionen gelegt. Es wird gezeigt, dass die Wechselwirkung nicht exakt elastisch ist, sondern dass ein Teil ihrer Energie an der Position der Kollision verharrt. In endlichen Gittern führt dies zu einem multiplen Streuprozess, welcher in einem chaotischen Zustand endet.
Wersäll, Carl. "Frequency Optimization of Vibratory Rollers and Plates for Compaction of Granular Soil". Doctoral thesis, KTH, Jord- och bergmekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187352.
Pełny tekst źródłaQC 20160613
Woudberg, Sonia. "Laminar flow through isotropic granular porous media". Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1320.
Pełny tekst źródłaSwartzel, Jeffrey M. "Rolling of an Elliptic-Shaped Particle in Two Dimensions: A Mathematical Model". Akron, OH : University of Akron, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1240522472.
Pełny tekst źródła"May, 2009." Title from electronic thesis title page (viewed 7/28/2009) Advisor, Dmitry Golovaty; Faculty Readers, Gerald Young, Patrick Wilber; Department Chair, Joseph Wilder; Dean of the College, Chand Midha; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
Jongchansitto, Pawarut. "Mechanical analysis of 2D composite granular materials : thermomechanical experiments and numerical simulations". Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22592/document.
Pełny tekst źródłaThe main objective of our dissertation is to analyze the mechanical behavior of two-dimensional composite granular materials through the granular textures. Thermoelatic stress analysis experiments and molecular dynamics simulations are used for this purpose. The composite granular systems are prepared from polyoxymethylene (POM) and high-density polyethylene (HDPE) cylinders with a stiffness ratio of about 4 between them. Different configurations in terms of ratios of diameter size and ratio of particle numbers are systematically investigated. Experimental and numerical results are good correlated at the macroscopic scale. In particular the strong network, which is here characterized by hydrostatic stresses higher than the mean value, consists of less than 50% of all particles, and exhibits an exponential decay whatever the type of particles considered for the analysis (soft, stiff, or both types). In addition, the contact distributions between stiff particles (POM-POM contacts) is anisotropic with an effort to arrange parallel to the direction of the external applied load, whereas the other types of contacts just act to sustain the granular system in equilibrium
Wang, Ruopeng 1972. "Study of gas flow dynamics in porous and granular media with laser-polarized ¹²⁹Xe NMR". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34652.
Pełny tekst źródłaIncludes bibliographical references (p. 173-182).
This thesis presents Nuclear Magnetic Resonance (NMR) studies of gas flow dynamics in porous and granular media by using laser-polarized ¹²⁹Xe . Two different physical processes, the gas transport in porous rock cores and the mass exchanges between different phases in fluidized granular systems, were investigated and new experimental methods were designed to measure several important parameters characterizing the two systems. Methods for measuring the parameters had been either unavailable or significantly limited previously. The research involved modeling the gas flow in porous and granular media by relating the dynamics of spin magnetization to the interesting parameters, as well as correspondingly designing new measurement methods and verifying them on the laboratory test beds. We proposed a simple method to measure two important parameters of reservoir rocks, permeability and effective porosity, by probing the flow front of laser-polarized xenon gas inside the rock cores. The method was thoroughly tested on different categories of rocks with permeability values spanning two orders of magnitude, and the results were in agreement with those from the established techniques.
(cont.) The uniqueness in the work is that the fast method developed is capable of measuring the two parameters simultaneously on the same setup. Bubble-emulsion exchange and emulsion-adsorption exchange in a fluidized bed are two processes crucial to the efficiency of many chemical reactors working in bubbling regime. We used differences in T2 and chemical shift to contrast the three phases in the xenon spectra, and designed methods to measure the inter-phase exchange rates. The measured results of the bubble-emulsion and emulsion-adsorption exchange rates agreed well with predictions based on available theory. Our approach is the first to non-invasively probe natural bubbles in a three-dimensional bed, and to measure the exchange rate between the emulsion phase and multiple bubbles.
by Ruopeng Wang.
Ph.D.
Luomaranta, Henri. "Essays in Firm Dynamics, Ownership and Aggregate Effects". Thesis, Toulouse 1, 2019. http://www.theses.fr/2019TOU10021/document.
Pełny tekst źródłaAdministrative registers maintained by statistical offices on vastly heterogeneous firms have much untapped potential to reveal details on sources of productivity of firms and economies alike. It has been proposed that firm-level shocks can go a long way in explaining aggregate fluctuations. Based on novel monthly frequency data, idiosyncratic shocks are able to explain a sizable share of the Finnish economic fluctuations, providing support to the granular hypothesis. The global financial crisis of 2007-2008 has challenged the field of economic forecasting, and nowcasting has become an active field. This thesis shows that the information content of firm-level sales and truck traffic can be used for nowcasting GDP figures, by using a specific mixture of machine learning algorithms. The agency problem lies at the heart of much of economic theory. Based on a unique dataset linking owners, CEOs and firms, and exploiting plausibly exogenous variations in the separation of ownership and control, agency costs seem to be an important determinant of firm productivity. Furthermore, the effect appear strongest in medium-sized firms. Enterprise group structures might have important implications on the voluminous literature on firm size, as large share of SME employment can be attributed to affiliates of large business groups. Within firm variation suggests that enterprise group affiliation has heterogeneous impacts depending on size, having strong positive impact on productivity of small firms, and negative impact on their growth. In terms of aggregate job creation, it is found that the independent small firms have contributed the most. The results in this thesis underline the benefits of paying attention to samples encompassing the total population of firms. Researchers should continue to explore the potential of rich administrative data sources at statistical offices and strive to strengthen the ties with data producers
Maladen, Ryan Dominic. "Biological, simulation, and robotic studies to discover principles of swimming within granular media". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/42852.
Pełny tekst źródłaPreclik, Tobias [Verfasser], i Ulrich [Akademischer Betreuer] Rüde. "Models and Algorithms for Ultrascale Simulations of Non-smooth Granular Dynamics / Tobias Preclik. Gutachter: Ulrich Rüde". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2014. http://d-nb.info/1075478987/34.
Pełny tekst źródłaÖnder, Koray [Verfasser], Ralf [Gutachter] Bulla i Matthias [Gutachter] Sperl. "Dynamics close to Bifurcations: From Spins to Granular Media / Koray Önder ; Gutachter: Ralf Bulla, Matthias Sperl". Köln : Universitäts- und Stadtbibliothek Köln, 2019. http://d-nb.info/1199537314/34.
Pełny tekst źródłaSunthar, P. "Characterisation and Analysis of a Vibro-fluidised Granular Material". Thesis, Indian Institute of Science, 2001. http://hdl.handle.net/2005/249.
Pełny tekst źródłaSandlin, Matthew. "An experimental and numerical study of granular hopper flows". Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50318.
Pełny tekst źródłaZhang, Fengshou. "Pattern formation in fluid injection into dense granular media". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43716.
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