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Tesi sul tema "Model solutions"
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1
Ozkan, Ibrahim Ali. "Thermodynamic model for associating polymer solutions". Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-05042004-142825/unrestricted/ozkan%5Fibrahim%5Fa%5F200408%5Fphd.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2005. Directed by Amyn S. Teja.Dr. Thomas H. Sanders, Committee Member ; Dr. Peter J. Ludovice, Committee Member ; Dr. J. Carson Meredith, Committee Member ; Dr. William J. Koros, Committee Member ; Dr. Amyn S. Teja, Committee Chair. Includes bibliographical references.
2
Thomas, Lori Ann. "Nonperturbative solutions to the Hubbard Model". DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 1987. http://digitalcommons.auctr.edu/dissertations/1179.
Testo completoAbstract (sommario):
Nonperturbative solutions to the Hubbard model are found by using the functional derivative method. A system of closed equations is obtained for the Green's functions of the Hubbard model. Exact expressions for the self-energy are derived which involve only first order functional derivatives. A scheme is proposed for systematically calculating self-energy corrections. We apply the solution to finite rings of two and four lattice sites and compare to the results of numerical calculations on these systems.
3
Ridderstolpe, Ludwig. "Exact Solutions of the Ising Model". Thesis, Uppsala universitet, Teoretisk astrofysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-329081.
Testo completoAbstract (sommario):
This report presents the general Ising model and its basic assumptions. This study aims to, from diagonalization of the Transfer Matrix, obtain the Helmholtz free energy and the exclusion of a phase transition for the one-dimensional Ising model under an external magnetic field. Furthermore from establishing the commutation relations of the Transfer matrices and using the Kramers-Wannier duality one finds the free energy and the presence of a phase transition for the square-lattice Ising model.
4
Davis, Brian M. "Traveling wave solutions for a combustion model". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2578.
Testo completoAbstract (sommario):
Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Applied Mathematics and Scientific Computation Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
5
Wahler, Matthias, e Thomas Sendelbach. "Model based engineering for electro-hydraulic solutions". Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71232.
Testo completoAbstract (sommario):
This paper will give an overview about the technological change in Industrial Hydraulics and the impact of the Digital Twin on the related new engineering processes and methods in order to overcome the challenges coming out of that technology change. Simulation models will more and more become a decisive factor for the engineering process. The Digital Twin will be a window of opportunity for innovations and a technology push for the engineering process and the products in the Industrial Hydraulics.
6
Alzahrani, Abdulah. "Local travelling wave solutions and self-similar solutions for a green roof model". Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2776.
Testo completoAbstract (sommario):
In this thesis we study travelling wave solutions and self-similar solutions for a green roof model and for some simpler models which are derived from that model. We focus on two limiting cases near a dry region and near a saturated region. We start by considering a convection model in the absence of diffusion and sink terms. We show that rarefaction waves and shock solutions exist for several cases. Next, we consider a convection-diffusion model where both the convective and diffusive terms are present and we show that travelling wave solutions and self-similar solutions exist for some cases. Moreover, numerical simulations are used for the travelling wave and self-similar solutions and confirm the analytic predictions. Finally, we consider the green roof model where all terms are present and we show that travelling wave solutions exist, whereas self-similar solutions are not found. We also show the travelling wave solutions exist for the two limiting cases.
7
Liceaga, Daniel Olmos. "Pseudospectral solutions of reaction-diffusion equations that model excitable media : convergence of solutions and applications". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31453.
Testo completoAbstract (sommario):
In this thesis, I develop accurate and efficient pseudospectral methods to solve Fisher's, the Fitzhugh-Nagumo and the Beeler-Reuter equations. Based on these methods, I present a study of spiral waves and their interaction with a boundary. The solutions of Fisher's equation are characterized by propagating fronts with a, shock-like wave behavior when large values of the reaction rate coefficient is taken. The pseudospectral method employed for its solution is based on Chebyshev-Gauss-Lobatto quadrature points. I compare results for a single domain as well as for a subdivision of the main domain into subintervals. Instabilities that occur in the numerical solution for a single domain, analogous to those found by others, are attributed to round-off errors arising from numerical features of the discrete second derivative matrix operator. However, accurate stable solutions of Fisher's equation are obtained with a multidomain pseudospectral method. A detailed comparison of the present approach with the use of the sinc interpolation is also carried out. Also, I present a study of the convergence of different numerical schemes in the solution of the Fitzhugh-Nagumo equations. These equations, have spatial and temporal dynamics in two different scales and the solutions exhibit shock-like waves. The numerical schemes employed are Chebyshev multidomain, Fourier pseudospectral, finite difference methods and in particular a method developed by Barkley. I consider two different models of the local dynamics. I present results for plane wave propagation in one dimension and spiral waves for two dimensions. I use an operator splitting method with the Chebyshev multidomain approach in order to reduce the computational time. I conclude this thesis by presenting a study of the interaction of a meandering spiral wave with a boundary, where the Beeler-Reuter model is considered. The phenomenon of annihilation or reflection of a spiral at the boundaries of the domain is studied, when the trajectory of the tip of a spiral wave is essentially linear. This phenomenon is analyzed in terms of the variable j, which controls the reactivation of the sodium channel in the Beeler-Reuter model.Science, Faculty of
Mathematics, Department of
Graduate
8
Galstyan, Anahit. "Existence and Number of Global Solutions to Model Nonlinear Partial Differential Equations". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1115841126.
Testo completo
9
hammadi-Khashouie, Ghorbanali. "Sequencing mixed-model assembly lines in just-in-time production systems". Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/5770.
Testo completoAbstract (sommario):
This thesis proposes a new simulated annealing approach to solve multiple objective sequencing problems in mixed-model assembly lines. Mixed-model assembly lines are a type of production line where a variety of product models similar in product characteristics are assembled. Such an assembly line is increasingly accepted in industry to cope with the recently observed trend of diversification of customer demands. Sequencing problems are important for an efficient use of mixed-model assembly lines. There is a rich of criteria on which to judge sequences of product models in terms of line utilization. We consider three practically important objectives: the goal of minimizing the variation of the actual production from the desired production, which is minimizing usage variation, workload smoothing in order to reduce the chance of production delays and line stoppages and minimizing total set-ups cost. A considerate line manager would like to take into account all these factors. These are important for an efficient operation of mixed-model assembly lines. They work efficiently and find good solution in a very short time, even when the size of the problem is too large. The multiple objective sequencing problems is described and its mathematical formulation is provided. Simulated annealing algorithms are designed for near or optimal solutions and find an efficiency frontier of all efficient design configurations for the problem. This approach combines the SA methodology with a specific neighborhood search, which in the case of this study is a "swapping two sequence". Two annealing methods are proposed based on this approach, which differ only in cooling and freezing schedules. This research used correlation to describe the degree of relationship between results obtained by method B and other heuristics method and also for quality of our algorithm ANOVA's of output is constructed to analyse and evaluate the accuracy of the CPU time taken to determine near or optimal solution.
10
Floratos, Ioannis. "Multi-Skyrmion solutions of a sixth order Skyrme model". Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3988/.
Testo completoAbstract (sommario):
In this Thesis, we study some of the classical properties of an extension of the Skyrme model defined by adding a sixth order derivative term to the Lagrangian. In chapter 1, we review the physical as well as the mathematical motivation behind the study of the Skyrme model and in chapter 2, we give a brief summary of various extended Skyrme models that have been proposed over the last few years. We then define a new sixth order Skyrme model by introducing a dimensionless parameter λ that denotes the mixing between the two higher order terms, the Skyrme term and the sixth order term. In chapter 3 we compute numerically the multi-skyrmion solutions of this extended model and show that they have the same symmetries with the usual skyrmion solutions. In addition, we analyse the dependence of the energy and radius of these classical solutions with respect to the coupling constant λ. We compare our results with experimental data and determine whether this modified model can provide us with better theoretical predictions than the original one. In chapter 4, we use the rational map ansatz, introduced by Houghton, Manton and Sutcliffe, to approximate minimum energy multi-skyrmion solutions with B ≤ 9 of the SU(2) model and with B ≤ 6 of the SU(3) model. We compare our results with the ones obtained numerically and show that the rational map ansatz works just as well for the generalised model as for the pure Skyrme model, at least for B ≤ 5. In chapter 5, we use a generalisation of the rational map ansatz, introduced by loannidou, Piette and Zakrzewski, to construct analytically some topologically non-trivial solutions of the extended model in SU(3). These solutions are spherically symmetric and some of them can be interpreted as bound states of skyrmions. Finally, we use the same ansatz to construct low energy configurations of the SU(N) sixth order Skyrme model.
11
Liu, Bing. "Properties Model for Aqueous Sodium Chloride Solutions near the Critical Point of Water". Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd1034.pdf.
Testo completo
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Koskiola, Annina. "Mobile solutions and the museum experience". Thesis, Stockholms universitet, Konstvetenskapliga institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-105626.
Testo completoAbstract (sommario):
This thesis presents four case studies from the Finnish museum sector that are using mobile technologies in diverse ways to enhance the museum experience. At the National Museum of Finland, the mobile solution functions as an aid for providing translations in different languages and thus improving the aesthetic appearance of the exhibition. At Tampere Art Museum, the outdoors mobile tour extends the museum visit outside the physical walls of the building. At Helsinki City Museum the mobile phone is perceived as a communication tool. At Luostarinmäki Handicrafts Museum the Augmented Reality game combines digital narrative with real-world events, creating a solution that is both entertaining and informative. These solutions are analysed in terms of the Contextual Model, developed by Falk and Dierking. The model divides the museum visit into three overlapping and interacting spheres – personal, social and physical. This thesis looks at how mobile solutions may enhance or hinder the museum experience in regards to each of these three spheres. Additionally, the model is compared with the results of a visitor research conducted at the National Museum of Finland in October 2013. The aim of the thesis is to identify the most successful features of these solutions and to explore how the field could be developed in the future.
13
Alves, Victor César Costa [UNESP]. "Painlevé Integrability and mixed P_III-P_V system solutions". Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/149963.
Testo completoAbstract (sommario):
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O presente trabalho trata de um abordagem de aplicações em física dos métodos matemáticos de integrabilidade de Painlevé, por outro lado também aborda o formalismo de hierarquias integráveis e o modelo de 2M-bosons onde são usados métodos de equações diferenciais bem como um método para soluções usando aproximantes de Padé.
The current work aims at applications of mathematical methods of Painlevé integrability in physics, on the other side it also approaches the integrable hierarchies formalism and the 2M-bose model where differential equations methods are used as well as a method for solutions using Padé approximants.
14
Lämmel, Marc, Evelin Jaschinski, Rudolf Merkel e Klaus Kroy. "Microstructure of sheared entangled solutions of semiflexible polymers". Forschungszentrum Jülich, 2016. https://ul.qucosa.de/id/qucosa%3A15029.
Testo completoAbstract (sommario):
We study the influence of finite shear deformations on the microstructure and rheology of solutions of entangled semiflexible polymers theoretically and by numerical simulations and experiments with filamentous actin. Based on the tube model of semiflexible polymers, we predict that large finite shear deformations strongly affect the average tube width and curvature, thereby exciting considerable restoring stresses. In contrast, the associated shear alignment is moderate, with little impact on the average tube parameters, and thus expected to be long-lived and detectable after cessation of shear. Similarly, topologically preserved hairpin configurations are predicted
to leave a long-lived fingerprint in the shape of the distributions of tube widths and curvatures. Our numerical and experimental data support the theory.
15
Alves, Victor César Costa. "Painlevé Integrability and mixed P_III-P_V system solutions /". São Paulo, 2017. http://hdl.handle.net/11449/149963.
Testo completoAbstract (sommario):
Orientador: Abraham Hirsz ZimermanAbstract: The current work aims at applications of mathematical methods of Painlevé integrability in physics, on the other side it also approaches the integrable hierarchies formalism and the 2M-bose model where differential equations methods are used as well as a method for solutions using Padé approximants.
Resumo: O presente trabalho trata de um abordagem de aplicações em física dos métodos matemáticos de integrabilidade de Painlevé, por outro lado também aborda o formalismo de hierarquias integráveis e o modelo de 2M-bosons onde são usados métodos de equações diferenciais bem como um método para soluções usando aproximantes de Padé.
Mestre
16
Ou, Zhaoyang. "An association model for specific-interaction effects in random copolymer solutions". Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/9140.
Testo completo
17
Halsey, Scott Anthony. "Model-based solutions for structural coupling in flight control systems". Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/33748.
Testo completoAbstract (sommario):
Structural Coupling is the interaction between an aircraft's Flight Control System (FCS) and its structural and aero-dynamics. These interactions have the potential to cause significant problems to the aircraft, possibly through structural fatigue failure, or by corruption of sensor readings leading to degradation of the FCS loop. Presently notch filters are used to attenuate the sensor signals at the structural mode frequencies which cause significant problems. However, each of these notch filters adds a small amount of phase lag to the control loop which limits the performance of the FCS. This research has looked at using Kalman filters to provide an alternative approach to overcoming the structural coupling problem.
18
Silva, Ana Soraia Pires. "Origin of honey oligosaccharides: from model solutions to hive conditions". Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22394.
Testo completoAbstract (sommario):
Mestrado em Biotecnologia - AlimentarHoney is essentially composed by carbohydrates, fructose (38 %) and glucose (31 %), mainly resultant of invertase activity. Furthermore, several oligosaccharides can be identified in honey, comprising 5 to 10 % of total carbohydrates. The origin of these oligosaccharides is still uncertain, as most of them are not present neither in nectar or in pollen. The research on this subject, mainly conducted in the past century, demonstrated the capability of invertase, namely the α-glucosidase activity, to transfer α-glucosyl residues to other carbohydrate moieties. As this transglucosylation activity was reported both to bees’ and honey’s invertases, it was proposed that the action of invertase was the source for α-glucose linked sugars. Nonetheless, there is still no explanation for the origin of the remaining oligosaccharides. The present work hypothesizes that nonenzymatic reactions could also occur in honey promoting the formation of oligosaccharides. This can be supported by the fact that honey maturation conditions, such as high sugar concentrations in acidic media, induce condensation of carbohydrates, reactions also known as reversion reactions. In order to validate this hypothesis, six aqueous model solutions (moisture content of 20 %) containing sucrose plus glucose, and sucrose plus fructose were prepared using diluted citric acid at pH 4.0, pH 2.0, and with no acid addition. The model solutions were kept in an oven at 35 ⁰C, which is the normal temperature inside beehives with brood production. Besides the influence of honey maturation conditions on its oligosaccharides profile was assessed by analysis of honeys with different properties, particularly the duration and season of maturation. Electrospray ionization mass spectrometry (ESI-MS) analysis allowed monitoring the changes occurring in each model solution along 5 months. This method revealed the occurrence of non-enzymatic oligosaccharide synthesis with a degree of polymerization (DP) up to 6 after 5 months. Ligand-exchange/size-exclusion chromatography (LEX-SEC) separation of the oligosaccharides formed in model solutions and present in honey and methylation analysis allowed to observe that the produced oligosaccharides had a glycosidic linkage composition similar to that obtained for honey oligosaccharides. In higher amounts, for most fractions, were terminally-linked glucose (Glc) residues together with lower amounts of (1->2)-, (1->4)- and (1->6)-Glc. Concerning fructose, terminally-linked fructose (Fru) residues were the most abundant and (2->1)- and (2->6)-Fru were in minor amounts. In addition, several branched residues were identified, being (1->2,3,4,6)-Glc the most abundant, and found predominantly in solutions prepared with citric acid. The structure and identity of the oligosaccharides were further elucidated by gas-chromatography coupled to mass-spectrometry (GC-MS) after derivatization to the alditol acetates derivatives.
O mel é composto essencialmente por hidratos de carbono, sendo a frutose (38 %) e a glucose (31 %) maioritariamente resultantes da atividade da invertase. Além disso, vários oligossacarídeos foram identificados no mel, constituindo 5 a 10 % do total dos açúcares. A origem destes oligossacarídeos ainda é incerta, uma vez que a maioria não é reportada nem no néctar nem no pólen. A investigação desta temática, maioritariamente conduzida no século passado, demonstraram a capacidade da invertase, designadamente a atividade de α-glucosidase, em transferir resíduos α-glucosyl para grupos funcionais de outros hidratos de carbono. Uma vez que esta atividade de transglucosilação foi reportada tanto para a invertase das abelhas como do mel, especulou-se que a ação desta enzima estivesse na origem dos açúcares com ligações de α-glucose. No entanto, ainda não existe uma explicação para a origem dos restantes oligossacarídeos. O presente trabalho coloca a hipótese de que reações não enzimáticas possam ocorrer no mel, promovendo a formação de oligossacarídeos. Esta hipótese pode ser suportada pelo facto das condições de maturação do mel, como as concentrações elevadas de açúcar em meio ácido, induzirem à condensação dos hidratos de carbono, reações também designadas por reações de reversão. De forma a validar esta hipótese, seis soluções modelo aquosas (teor de humidade de 20 %) de sacarose com glucose e de sacarose com frutose foram preparadas com ácido cítrico diluído a pH 4.0, a pH 2.0 e sem adição de ácido. As soluções foram mantidas numa estufa a 35⁰C, correspondente à temperatura média no interior da colmeia aquando da criação do ninho. Também se acedeu à influência das condições de maturação do mel no seu perfil de oligossacarídeos, através da análise de méis com diferentes propriedades, destacando-se a duração e o tempo de maturação. As análises de ionização em electrospray acopladas a espectrometria de massa (ESI-MS) permitiram monitorizar as alterações que ocorreram nas soluções durante 5 meses. Este método revelou a ocorrência da síntese de oligossacarídeos não enzimática, com um DP máximo observado de 6, após 5 meses. A separação dos açúcares formados nas soluções modelo e presentes nos méis através de cromatografia de afinidade e de exclusão-molecular (LEX-SEC) e a análise de metilação permitiram observar que os oligossacarídeos produzidos tinham uma composição em ligações glicosídicas semelhante à dos oligossacarídeos do mel. A maioria das frações era composta principalmente por resíduos de glucose ligados pelo terminal e por resíduos de fructose ligada terminalmente e, em menor quantidade, por resíduos de glucose com ligações (1->2), (1->4) e (1->6) e por resíduos de frutose com ligações (2->1), (2->3) e (2->6). Também foram identificados resíduos correspondentes a ramificações, sendo o (1->2,3,4,6) -Glc o mais abundante e encontrado predominantemente em soluções elaboradas com ácido cítrico. A estrutura e a identidade dos oligossacarídeos anteriormente mencionados foram clarificados através da cromatografia gasosa acoplada à espectrometria de massa, após derivatização nos seus acetatos de alditol.
19
Ikeda, Tsutomu. "Standing pulse-like solutions of a spatially aggregating population model". 京都大学 (Kyoto University), 1985. http://hdl.handle.net/2433/86351.
Testo completo
20
Henriksson, Johan. "Generating Solutions in General Relativity using a Non-Linear Sigma Model". Thesis, Uppsala universitet, Teoretisk fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226272.
Testo completoAbstract (sommario):
This report studies the generation of new solutions to Einstein's field equations in general relativity by the method of sigma models. If, when projected from four to three dimensions, the relativistic action decouples into a gravity term and a non-linear sigma model term, target space isometries of the sigma model can be found that correspond to generating new solutions. We give a self-contained description of the method and relate it to the early articles through which the method was introduced. We discuss the virtues of the method and how it is used today. We find that it is a powerful technique of finding new solutions and can also give insight to the general features of the theory. We also identify some possible further developments of the method.
21
Uwaha, Makio, e Katsunobu Koyama. "Transition from nucleation to ripening in the classical nucleation model". Elsevier, 2010. http://hdl.handle.net/2237/13867.
Testo completo
22
Yagdjian, Karen, e Anahit Galstian. "Fundamental solutions for wave equation in de Sitter model of universe". Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2009/3027/.
Testo completoAbstract (sommario):
In this article we construct the fundamental solutions for the wave equation arising in the de Sitter model of the universe. We use the fundamental solutions to represent solutions of the Cauchy problem and to prove the Lp − Lq-decay estimates for the solutions of the equation with and without a source term.
23
Wünsch, Rudi. "Self-Consistent Solutions of the Semibosonized Nambu & Jona-Lasinio Model". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-32670.
Testo completo
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Fang, Daoyuan, e Jiang Xu. "Asymptotic behavior of solutions to multidimensional nonisentropic hydrodynamic model for semiconductors". Universität Potsdam, 2005. http://opus.kobv.de/ubp/volltexte/2009/2976/.
Testo completoAbstract (sommario):
In this paper, a global existence result of smooth solutions to the multidimen-
sional nonisentropic hydrodynamic model for semiconductors is proved, under the
assumption that the initial data is a perturbation of the stationary solutions for the thermal equilibrium state. The resulting evolutionary solutions converge to the stationary solutions in time asymptotically exponentially fast.
25
Bilodeau, Bernard. "Accuracy of a truncated barotropic spectral model : numerical versus analytical solutions". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66037.
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Martin, Hazel Pauline. "Microfluidic processing and in-situ analysis of model concentrated surfactant solutions". Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538704.
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Konko, Iuliia. "Aqueous solutions of complexes formed by model polyelectrolytes of opposite charges". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE049/document.
Testo completoAbstract (sommario):
Cette thèse présente une étude des solutions aqueuses de trois complexes de polyélectrolytes (PECs) modèles. Les PECs résultent de la complexation de deux polyélectrolytes linéaires de charge opposée: un polycation (le PDADMA) et trois polyanions de longueur de persistance non électrostatique distinctes: le polystyrene sulfoné (PSS), le poly(α-méthyl styrène sulfoné) (PαMSS) et l’acide hyaluronique (HA). En plus de l’influence de la rigidité intrinsèque des polyanions sur la formation et la structure des PECs, les effets de la force ionique et de la méthode de préparation des solutions aqueuses de PECs ainsi que l’influence de la concentration des solutions binaires de polyélectrolytes initiales ont également été abordés. Nous suggérons que le processus de complexation entre polycations et polyanions en régimes semidilué et concentré est analogue à une gélification. Il y a toutefois une différence entre les deux complexes qui est reliée à la différence de rigidité intrinsèqueThis PhD thesis presents a study of the aqueous solutions of three model polyelectrolyte complexes (PECs). PECs were formed between hydrophilic and highly charged linear macrocations of poly(diallyldimethyl ammonium) (PDADMA) and linear macroanions of distinct intrinsic persistence lengths: sulfonated polystyrene (PSS), sulfonated poly(α-methyl styrene) (PαMSS) and hyaluronate (HA). In addition to the effect of the macroion stiffness on the PEC formation and structure, those of the ionic strength and the way of preparing the PEC aqueous solutions as well as that of the concentration regimes of the initial PE aqueous solutions were also tackled. We suggest the complexation between macrocations and macroanions in the semidilute and concentrated regimes can be described as a universal gelation process. A difference between PDADMA-PSS and PDADMA-HA complexes is related to the primary self-assembling process and is associated with the distinct structural models for PECs
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Wünsch, Rudi. "Self-Consistent Solutions of the Semibosonized Nambu & Jona-Lasinio Model". Forschungszentrum Rossendorf, 1993. https://hzdr.qucosa.de/id/qucosa%3A22094.
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Lee, Euiwoo. "Uniqueness results for bursting solutions in a model of excitable membranes /". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487848078450791.
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Khames, Imene. "Nonlinear network wave equations : periodic solutions and graph characterizations". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMIR04/document.
Testo completoAbstract (sommario):
Dans cette thèse, nous étudions les équations d’ondes non-linéaires discrètes dans des réseaux finis arbitraires. C’est un modèle général, où le Laplacien continu est remplacé par le Laplacien de graphe. Nous considérons une telle équation d’onde avec une non-linéarité cubique sur les nœuds du graphe, qui est le modèle φ4 discret, décrivant un réseau mécanique d’oscillateurs non-linéaires couplés ou un réseau électrique où les composantes sont des diodes ou des jonctions Josephson. L’équation d’onde linéaire est bien comprise en termes de modes normaux, ce sont des solutions périodiques associées aux vecteurs propres du Laplacien de graphe. Notre premier objectif est d’étudier la continuation des modes normaux dans le régime non-linéaire et le couplage des modes en présence de la non-linéarité. En inspectant les modes normaux du Laplacien de graphe, nous identifions ceux qui peuvent être étendus à des orbites périodiques non-linéaires. Il s’agit des modes normaux dont les vecteurs propres du Laplacien sont composés uniquement de {1}, {-1,+1} ou {-1,0,+1}. Nous effectuons systématiquement une analyse de stabilité linéaire (Floquet) de ces orbites et montrons le couplage des modes lorsque l’orbite est instable. Ensuite, nous caractérisons tous les graphes pour lesquels il existe des vecteurs propres du Laplacien ayant tous leurs composantes dans {-1,+1} ou {-1,0,+1}, en utilisant la théorie spectrale des graphes. Dans la deuxième partie, nous étudions des solutions périodiques localisées spatialement. En supposant une condition initiale de grande amplitude localisée sur un nœud du graphe, nous approchons l’évolution du système par l’équation de Duffing pour le nœud excité et un système linéaire forcé pour le reste du réseau. Cette approximation est validée en réduisant l’équation φ4 discrète à l’équation de Schrödinger non-linéaire de graphes et par l’analyse de Fourier de la solution numérique. Les résultats de cette thèse relient la dynamique non-linéaire à la théorie spectrale des graphesIn this thesis, we study the discrete nonlinear wave equations in arbitrary finite networks. This is a general model, where the usual continuum Laplacian is replaced by the graph Laplacian. We consider such a wave equation with a cubic on-site nonlinearity which is the discrete φ4 model, describing a mechanical network of coupled nonlinear oscillators or an electrical network where the components are diodes or Josephson junctions. The linear graph wave equation is well understood in terms of normal modes, these are periodic solutions associated to the eigenvectors of the graph Laplacian. Our first goal is to investigate the continuation of normal modes in the nonlinear regime and the modes coupling in the presence of nonlinearity. By inspecting the normal modes of the graph Laplacian, we identify which ones can be extended into nonlinear periodic orbits. They are normal modes whose Laplacian eigenvectors are composed uniquely of {1}, {-1,+1} or {-1,0,+1}. We perform a systematic linear stability (Floquet) analysis of these orbits and show the modes coupling when the orbit is unstable. Then, we characterize all graphs for which there are eigenvectors of the graph Laplacian having all their components in {-1,+1} or {-1,0,+1}, using graph spectral theory. In the second part, we investigate periodic solutions that are spatially localized. Assuming a large amplitude localized initial condition on one node of the graph, we approximate its evolution by the Duffing equation. The rest of the network satisfies a linear system forced by the excited node. This approximation is validated by reducing the discrete φ4 equation to the graph nonlinear Schrödinger equation and by Fourier analysis. The results of this thesis relate nonlinear dynamics to graph spectral theory
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Wu, Ning. "Artificial intelligence solutions for models of dynamic land use change". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610781.
Testo completo
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Carrião, Renato Lewenthal. "Method to represent IoT solutions during the Business Model Design of a Product-Service System (PSS)". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18156/tde-12112018-141032/.
Testo completoAbstract (sommario):
Considering the competitiveness of global markets within an ever-changing environment, a company\'s Business Model should be able to innovate constantly to capture value within the company, while addressing better the customer needs. The PSS Business Model represents an innovation while providing value to the customer supported by a combination of products and services. However, the PSS Business Model also needs to innovate constantly. The Internet of Things (IoT) comprises networked objects able to interact with each other and to people, to reach common goals with a high level of efficiency, thus presenting potential to create a new value proposition to PSS Business Model Design. However, the existing literature represents an IoT solution into PSS Design, using either technical constructs or a high level free textual description. The goal of this study is to propose a \"Method to support the representation of IoT solutions during the PSS Business Model Design\". The method was developed based on the Design Research Methodology (DRM), comprising three research stages. During the first and second stages, a literature review was conducted to generate theoretical requirements for guiding the proposition of the method. During the third stage, the requirements were developed, and multiple case studies using secondary sources were used to propose the method in theory. During the final activity of the third stage, an exploratory application of the method for a Driverless PSS Car Sharing were applied and its results, as well as all the method\'s artifacts, were object of an initial evaluation by a focus group. The results indicated that method has potential to provide a common language for the PSS Business Model designers, while providing detailed information, to be added to the dimensions of a PSS Business Model that comprises IoT solutions.Considerando a competitividade dos mercados globais dentro de um ambiente de constante mudança, o modelo de negócio de uma empresa deve ser capaz de inovar constantemente, capturando valor dentro da empresa ao mesmo tempo em que atende melhor as necessidades dos clientes. O modelo de negócio de PSS representa uma inovação ao entregar valor ao cliente através de uma combinação de produtos e serviços. No entanto, o modelo de negócio de PSS também precisa inovar constantemente. A Internet das coisas (IoT) compreende objetos em rede capazes de interagir uns com os outros e com as pessoas, para alcançar metas comuns com elevado nível de eficiência. Dessa forma, apresenta potencial para criar a nova proposta de valor para o desenho de modelo de negócio de PSS. No entanto, a literatura existente representa a solução de IoT usando ou constructos técnicos, ou um nível alto de descrição textual. O objetivo deste estudo é propor um \"Método de representação de soluções de internet das coisas (IoT) durante o design de um modelo de negócios de um Sistema produto-serviço (PSS)\". O método foi desenvolvido com apoio da Design Research Methodology (DRM), sendo composto de três fases de investigação. Durante a primeira e a segunda fase, realizou-se uma revisão da literatura para gerar requisitos teóricos para orientar a proposição de método. Durante a terceira fase, foram desenvolvidos requerimentos e analisados múltiplos estudos de caso, usando fontes secundárias, para propor o método na teoria. Durante a atividade final da terceira fase foi realizada uma aplicação exploratória do método, em um caso de um PSS de \"uso compartilhado de carros\" usando um carro autônomo. Em seguida todos os artefatos do método, e os resultados dessa aplicação exploratória, foram objeto de uma avaliação inicial por um grupo focal. Os resultados indicaram que o método tem potencial para fornecer uma linguagem comum para os desenvolvedores de modelo de negócio de PSS, proporcionando informações detalhadas, a serem adicionadas às dimensões de um modelo de negócio de PSS.
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麥民光 e Man-kwong Mak. "The relativistic static charged fluid sphere and viscous fluid cosmological model". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31237526.
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Mak, Man-kwong. "The relativistic static charged fluid sphere and viscous fluid cosmological model /". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19324352.
Testo completo
35
McPeak, David W. (David William). "The behavior of volatile fatty acids in model solutions during freeze-drying /". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65359.
Testo completo
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Kaiksow, Wedad A. "Labour supply problems and solutions : econometric model for the State of Bahrain". Thesis, City University London, 1999. http://openaccess.city.ac.uk/7715/.
Testo completoAbstract (sommario):
Despite the intentions of the State of Bahrain to implement significant economic and social changes, and their full, or partial, sponsorship of intensive training programmes, neither have the human resources available been exploited to their full potential, nor have the vocational training programmes managed to equip unemployed workers with the skills needed to compete effectively in the labour market. Indeed, the picture is hardly encouraging for future generations, and cries out for fundamental changes. Bahrain has poured investments into projects aimed at reaping the benefits of its relative advantages, into exploring and transforming its oil and gas resources, into developing value added products, and human resources. But changes since have created a whole new world, with no market to speak of but a global one. Any decisions on investment should now be guided by the notion that geographical location is no longer a real issue, and that competition is won more by conceptual than by material advantage. A worker's personal opinion of his job has as much impact on competition as the extent and quality of his training. An entirely new system is therefore needed, one that provides social incentives and traditional rewards for the creation of new concepts, ideas and perspectives. The aim of this thesis, is firstly, to investigate labour supply in Bahrain in a dynamic setting in the light of the neoclassical theory which is based mainly on that labour supply is largely a function of real wage. Secondly, to diagnose the problems and finally to suggest solutions. An econometric model of labour supply for different groups: Bahrainis and non-Bahrainis, primary and secondary workers is introduced. Use is made of cross-section time series data. The econometric contribution of this thesis is the testing of relative wage theory besides the estimation and the identification of labour supply elasticities that can serve as the basis for policy decisions. Unemployment as the most serious economic problem facing Governments is considered in this thesis. Unemployment model is presented and analysed as a function of specific factors that may cause structural unemployment in the economy of Bahrain. Use is made of secondary data. Then unemployment policies are discussed and finally the conclusion of this thesis with prospects is presented.
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Ivanova, Kseniya. "Mathematical model of multi-dimensional shear shallow water flows : problems and solutions". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0642/document.
Testo completoAbstract (sommario):
Cette thèse porte sur la résolution numérique du modèle multi-dimensionnel d'écoulement cisaillé en eau peu profonde. Dans le cas d'un mouvement unidimensionnel, ces équations coïncident avec les équations de la dynamique de gaz pour un choix particulier de l'équation d'état. Dans le cas multi-dimensionnel, le système est complètement différent du modèle de la dynamique de gaz. Il s'agit d'un système EDP hyperbolique 2D non-conservatif qui rappelle un modèle de turbulence barotrope. Le modèle comporte trois types d'ondes correspondant à la propagation des ondes de surface, des ondes de cisaillement et à celle de la discontinuité de contact. Nous présentons dans le cas 2D un schéma numérique basé sur une nouvelle approche de ``splitting" pour les systèmes d'équations non-conservatives. Chaque sous-système ne contient qu'une seule famille d'ondes: ondes de surface ou ondes de cisaillement, et discontinuité de contact. La précision d'une telle approche est testée sur des solutions exactes 2D décrivant l'écoulement lorsque la vitesse est linéaire par rapport aux variables spatiales, ainsi que sur des solutions décrivant des trains de rouleaux 1D. Finalement, nous modélisons un ressaut hydraulique circulaire formé dans un écoulement convergent radial d'eau. Les résultats numériques obtenus sont clairement similaires à ceux obtenus expérimentalement: oscillations du ressaut et son rotation avec formation du point singulier. L'ensemble des validations proposées dans ce manuscrit démontre les aptitudes du modèle et de la méthode numérique pour la résolution des problèmes complexes d'écoulements cisaillés en eau peu profonde multidimensionnelsThis thesis is devoted to the numerical modelling of multi-dimensional shear shallow water flows. In 1D case, the corresponding equations coincide with the equations describing non--isentropic gas flows with a special equation of state. However, in the multi-D case, the system differs significantly from the gas dynamics model. This is a 2D hyperbolic non-conservative system of equations which is reminiscent of a generic Reynolds averaged model of barotropic turbulent flows. The model has three families of characteristics corresponding to the propagation of surface waves, shear waves and average flow (contact characteristics). First, we show the ability of the one-dimensional conservative shear shallow water model to predict the formation of roll-waves from unstable initial data. The stability of roll waves is also studied.Second, we present in 2D case a new numerical scheme based on a splitting approach for non-conservative systems of equations. Each split subsystem contains only one family of waves (either surface or shear waves) and contact characteristics. The accuracy of such an approach is tested on exact 2D solutions describing the flow where the velocity is linear with respect to the space variables, and on the solutions describing 1D roll waves. Finally, we model a circular hydraulic jump formed in a convergent radial flow of water. Obtained numerical results are qualitatively similar to those observed experimentally: oscillation of the hydraulic jump and its rotation with formation of a singular point. These validations demonstrate the capability of the model and numerical method to solve challenging multi--dimensional problems of shear shallow water flows
38
Chen, Hua, e Shaohua Wu. "On existence of solutions for some hyperbolic-parabolic type chemotaxis systems". Universität Potsdam, 2006. http://opus.kobv.de/ubp/volltexte/2009/3008/.
Testo completo
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Kirby, Carl Scott. "Prediction of electrolyte solution properties using a combined Debye-Huckel, association and solvation model". Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/46043.
Testo completoAbstract (sommario):
This paper presents a semi-theoretical computer model that estimates individual and mean ionic activity coefficients in the NaCl-NaOH-HCl-H₂O system at 25°C. This extra thermodynamic model incorporates long-range electrostatic ion-ion interaction (Debye- Hückel effects), short-range ion-ion interactions (ion association), and short-range ion-solvent interactions (hydration). The activity of water in NaCl, NaOH, and HCl solutions is fit with maximum deviations from experimental values of 0.78%, 0.79%, and 2.09%, respectively. Ion size parameters, å, were modified slightly from literature values. Hydration numbers for individual species were chosen on the basis of best fit. Ion pair dissociation constants of 15.0 were chosen for reactions involving NaCl(aq), NaOH(aq), and HCl(aq) ion pairs. The model predicts individual ionic activity coefficients for ions and ion pairs, and predicts mean molal ionic activity coefficients for NaCl, NaOH, and HCl for solutions up to 6.0 m with maximum deviations from experimental values of 0.73%, 1.77%, and 3.86%,respectively. The estimated degree of dissociation varies widely if the ion pair dissociation constants are varied between 5 and 1000. Calculated values for trace activity coefficients, saturation solubility, and vapor pressure compare favorably to experimental data.Master of Science
40
Al-Hussyni, Saad Kohel Ali. "Numerical study of turbulent plane jets in still and flowing environments employing two-equation k-ε model". Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/11065.
Testo completo
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Hutter, Jonas, e Mehnaz Mashayeke. "A dynamic decision model and a system logic evaluation for Sandvik Machining Solutions distribution flows". Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-110571.
Testo completoAbstract (sommario):
The aim of this thesis is partly to create a dynamic decision model for Sandvik Machining Solutions distribution flows and partly to evaluate how the stock transfer system logic handle four specific exceptional situations. The purpose is to reduce the total costs while keeping or improving the service level. The thesis presents a total cost model and guidelines for the planning function when deciding the main supplier in the distribution. The thesis also presents a system logic evaluation of the stock transfer logic used by Sandvik Machining Solutions.
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Bondesson, Anna. "Comparative LCA model on renewable power solutions for off-grid radio base stations". Thesis, KTH, Industriell ekologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-53247.
Testo completoAbstract (sommario):
Globally, there are approximately 900 000 telecommunication radio base station sites (RBS-sites)located in areas without access to the electrical grid. Traditionally, these sites are powered by dieselgenerators, consuming large amounts of fossil diesel fuel. Diesel combustion is connected both toenvironmental impacts and high economical expenses for the mobile operators. As the mobilenetwork expansion is increasingly located in off-grid areas of developing countries, the search forrenewable power alternatives has been intensified. This Master thesis presents results from a life cycle assessment (LCA) of photovoltaic and windturbine hybrid power configurations for off-grid RBS-sites. The LCA covers environmental impactsfrom all life cycle activities of the hybrid system: from raw material extraction, manufacturing, andtransportation, to on-site usage, and disposal. To enable assessment of variable hybrid configurations, four scalable sub-models were constructed:one diesel sub-model including the generator and yearly diesel consumption, one back-up batterysub-model, one PV module sub-model and one wind turbine sub-model. Included in the sub-modelswere required site equipment; e.g. foundations for generators, PV modules and battery banks, powerconverters, fuel tanks and possible housings. The number of generators, liters of fuel consumed peryear, number of battery cells, square meters of PV module and number of wind turbines were set asvariables. Hereby RBS-sites with different capacities and availability of renewable source could bemodeled. A hybrid configuration including 21 square meters photovoltaic modules, one wind turbine, a storageof 36 (12 V) batteries and one generator back-up consuming 1500 liters of diesel fuel per year wasevaluated. The hybrid site represents between 11 and 16 percent of the different environmentalimpact potentials, global warming potential specifically representing 13 percent, caused by acorresponding traditional diesel site consuming 20000 liters of fuel per year. The most importantparameters influencing the environmental performance of the renewable hybrid site following thediesel fuel production and combustion are the production energy mix and energy intensive processesincluding the up-stream silicon and lead processing. The thesis confirmed great environmental benefits of using wind and solar power at RBS-sites. Theadditional gain of applying wind power when feasible to decrease the PV module area or batterycapacity required was also demonstrated. The great importance of manufacturing location andelectricity mix should encourage Ericsson to map supplier manufacturing locations, searchingpossibilities to decrease the environmental impacts from the manufacturing phase of the differentsub-systems.Idag finns det omkring 5 miljoner radiobasstationer i det i det globala telekomnätet, varav 900000 ärbelägna i områden utan tillgång till elektricitet. Traditionellt drivs dessa stationer av dieselgeneratorersom konsumerar stora mängder diesel. Dieselförbränningen bidrar både till lokala och globalamiljöeffekter samt höga driftkostnader för mobiloperatörerna. Expansionen av mobilnätet sker i alltstörre utsträckning i områden i utvecklingsländer utan elförsörjning, vilket har ökat intresset föralternativa kraftkällor. Inom examensarbetet har ett redskap för jämförande livscykelanalys (LCA) av förnyelsebara krafthybridlösningarför radiobasstationer utvecklats. Hybriderna kombinerar solceller och vindturbinermed dieselförbränning och batterier. Genom att använda LCA inkluderas miljöeffekter från alla steg i hybridsystemets livscykel; frånutvinning av råmaterial och tillverkning av sub-system, transport, användning på RBS-siten till denslutliga avvecklingen. För att kunna utvärdera olika hybridkonfigurationer skapades 4 olika delmodeller: en delmodell fördieselförbränning innefattande generator och dieselkonsumption, en batteri-delmodell, en PVdelmodellsamt en vindturbin-delmodell. Delmodellerna inkluderar även nödvändiga komponentersom betonggrund till generatorer, PV-modulerna och batteribanken. Antal dieselgeneratorer,battericeller, vindturbiner samt PV-moduler och liter dieselkonsumption kan varieras för att simuleraen specifik anläggning. En hybridlösning med 21 m2 solceller, en vindturbin, 36 stycken (12V) battericeller och endieselgenerator som konsumerar 1500 liter diesel per år analyserades. Hybridlösningen ger upphovtill miljöeffekter motsvarande mellan 11 och 16 procent, global uppvärmning motsvarande 13procent, av miljöeffekterna orsakade av en traditionell dieselkonfiguration som konsumerar omkring20000 liter diesel per år. Betydelsefulla parametrar som påverkar miljöeffekterna frånhybridlösningen förutom produktion och förbränning av diesel är vilken elektricitetsmix somanvänds vid tillverkning av de olika komponenterna och energiintensiva processer som kisel- ochblyframställning. Resultaten tydliggör de stora minskningar av miljöeffekterna som en övergång från dieselförbränningtill sol- och vindkraft på RBS-anläggningar kan ge. Den relativa förbättringen av att installeravindturbiner för att minimera mängden sol- och battericeller har även visats. Betydelsen avproduktionsplats och elektricitetsmix för den totala miljöpåverkan bör motivera Ericsson attkartlägga och välja tillverkare som innebär ett litet bidrag till de totala miljöeffekterna.
43
Gravel, Sylvie. "Periodic and stationary solutions to a forced-dissipated barotropic model of the atmosphere". Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75937.
Testo completoAbstract (sommario):
Using a barotropic model, some aspects of the theory of multiple equilibria were investigated, namely, the genesis of multiple equilibria via bent resonance, and the properties of some of the linearly unstable low index solutions.These studies were conducted using numerical models with a truncated spectral representation of the dependent variables, truncation that was determined in terms of its capacity to allow for nonlinear interactions. By means of a continuation algorithm, the stationary solutions of the potential vorticity equation were calculated for a number of regions of parameter space, allowing us to study the dependence of the steady solutions on an ensemble of parameters, including the geometry of the domain.
We can conclude that it is possible to observe the presence of more than one stable stationary solution for certain restricted regions of parameter space, but that in a majority of situations, only one solution is linearly stable. The latter, however, is not the only stable regime present since the unstable solution with the lowest zonal index is then surrounded by a stable periodic solution also of a low index type.
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Rose, Ian C. "Model investigation of initial fouling rates of protein solutions in heat transfer equipment". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0026/NQ38965.pdf.
Testo completo
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Iron, David. "The stability and dynamics of spike-type solutions to the Gierer-Meinhardt model". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ61117.pdf.
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Abu, Zaid Faried [Verfasser], Erich [Akademischer Betreuer] Grädel e Dietrich [Akademischer Betreuer] Kuske. "Algorithmic Solutions via Model Theoretic Interpretations / Faried Abu Zaid ; Erich Grädel, Dietrich Kuske". Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1162499648/34.
Testo completo
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Mayer, Timothy David. "Interactions of phosphorus and colloidal iron oxides in model solutions and natural waters /". Full text open access at:, 1995. http://content.ohsu.edu/u?/etd,214.
Testo completo
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Pleune, Thomas Todd 1974. "Integrated environmental degradation model for Fe-Ni-Cr alloys in irradiated aqueous solutions". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/84224.
Testo completoAbstract (sommario):
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1999.Includes bibliographical references.
An integrated model has been developed to evaluate the effect of reactor flux, fluence, and other operating conditions on crack growth rates in austenitic stainless steels in boiling water reactor (BWR) environments. The model evaluates the following in order to account for all factors affecting irradiation assisted stress corrosion cracking. *water chemistry including radiolysis and hydrogen injection *radiation induced segregation of the metal *radiation hardening of the metal *crack tip strain rate of a growing crack *dissolution rate at the crack tip following passive film rupture. The results of each of these models are combined to determine the crack advance rate for the given conditions. Environmentally assisted cracking (EAC) is a phenomenon where a combination of aggressive environment, susceptible material, and significant tensile stress result in accelerated degradation, including stress corrosion cracking (SCC), and hydrogen embrittlement. The EAC model is based on first principles electrochemistry and physical metallurgy. The effect of neutron and gamma radiation dose is included so that irradiation assisted stress corrosion cracking can be studied. By integrating the bulk chemistry with crack tip processes, the crack growth behavior of an aqueous system can be completely characterized. The model integrates chemistry and mechanical behavior to allow the study of EAC in general.
(cont.) EAC phenomena of interest include anodically driven stress corrosion cracking as well as cathodically driven hydrogen embrittlement. The model is able to predict measured data in the literature with good accuracy and precision. It predicts the effects of dose-rate and accumulated dose on stress corrosion cracking in BWRs. This model contributes to the field of crack growth modeling by creating a complete picture including all the major factors effecting crack growth in irradiated systems.
by Thomas Todd Pleune.
Ph.D.
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Marzo, i. Grimalt Núria. "Natural Language Processing Model for Log Analysis to Retrieve Solutions For Troubleshooting Processes". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-300042.
Testo completoAbstract (sommario):
In the telecommunications industry, one of the most time-consuming tasks is troubleshooting and the resolution of Trouble Report (TR) tickets. This task involves the understanding of textual data which can be challenging due to its domain- and company-specific features. The text contains many abbreviations, typos, tables as well as numerical information. This work tries to solve the issue of retrieving solutions for new troubleshooting reports in an automated way by using a Natural Language Processing (NLP) model, in particular Bidirectional Encoder Representations from Transformers (BERT)- based approaches. It proposes a text ranking model that, given a description of a fault, can rank the best possible solutions to that problem using answers from past TRs. The model tackles the trade-off between accuracy and latency by implementing a multi-stage BERT-based architecture with an initial retrieval stage and a re-ranker stage. Having a model that achieves a desired accuracy under a latency constraint allows it to be suited for industry applications. The experiments to evaluate the latency and the accuracy of the model have been performed on Ericsson’s troubleshooting dataset. The evaluation of the proposed model suggest that it is able to retrieve and re-rank solution for TRs with a significant improvement compared to a non-BERT model.En av de mest tidskrävande uppgifterna inom telekommunikationsindustrin är att felsöka och hitta lösningar till felrapporter (TR). Denna uppgift kräver förståelse av textdata, som försvåras as att texten innehåller företags- och domänspecifika attribut. Texten innehåller typiskt sett många förkortningar, felskrivningar och tabeller blandat med numerisk information. Detta examensarbete ämnar att förenkla inhämtningen av lösningar av nya felsökningar på ett automatiserat sätt med hjälp av av naturlig språkbehandling (NLP), specifikt modeller baserade på dubbelriktad kodrepresentation (BERT). Examensarbetet föreslår en textrankningsmodell som, givet en felbeskrivning, kan rangordna de bästa möjliga lösningarna till felet baserat på tidigare felsökningar. Modellen hanterar avvägningen mellan noggrannhet och fördröjning genom att implementera den dubbelriktade kodrepresentationen i två faser: en initial inhämtningsfas och en omordningsfas. För industrianvändning krävs att modellen uppnår en given noggrannhet med en viss tidsbegränsning. Experimenten för att utvärdera noggrannheten och fördröjningen har utförts på Ericssons felsökningsdata. Utvärderingen visar att den föreslagna modellen kan hämta och omordna data för felsökningar med signifikanta förbättringar gentemot modeller utan dubbelriktad kodrepresentation.
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Deen, Gary T., e Glenn G. Buni. "Development of a steady state model for forecasting U.S. Navy Nurse Corps personnel". Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1699.
Testo completoAbstract (sommario):
Approved for public release; distribution is unlimitedThis thesis developed a deterministic Markov state model to provide the U.S. Navy Nurse Corps a tool to more accurately forecast recruiting goals and future years force structure. Nurse Corps data was provided by the Nurse Corps Community Manager's office covering fiscal years 1990 to 2003. The probabilities used in the Markov model were derived from the fiscal year data. Transitions used in this model were stay at present grade, move up one grade or exit the system. Backward movement was not allowed and individuals could only move up one grade per year. The model was limited to eleven years and focused primarily on the ranks of O-1 to O-3. O-4's and O-5's that appeared in the data were allowed to flow through the system. Logistic regression was then used to investigate the probability of "staying" in the Nurse Corps to certain career decision points. Nurse Corps cohort data files for fiscal years 90 through 94 were merged for analysis, as was cohort data for fiscal year 96 through 98. Results of the markov model show that the O-1's and O-2's reach a steady state at the eight-year mark while the O-3's reach a steady state at the seventeen-year mark (based on provided data). The steady state values are compared to actual Nurse Corps goals. Results of the logistic regression show that Recalls, Medical Enlisted Commissioning Program and Nurse Candidate Program were all significant at increasing the probability of staying in the Nurse Corps. Males were more likely than females to stay in the Nurse Corps and changes in education levels decreased the probability of staying in the Nurse Corps.
Lieutenant, United States Navy