Дисертації з теми "Solution transport"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Solution transport.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Solution transport".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Hammadi, A. H. "Transport properties of electrolyte solutions in glycerol." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382843.
Повний текст джерела
2
Zuniga, Carlos A. "Solution-processable charge transport layers for phosphorescent OLEDs." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43671.
Повний текст джерелаАнотація:
The development of new charge transport materials for use in phosphorescent organic light-emitting diodes (OLEDs) remains an important area of research. In this thesis, several examples of carbazole-containing norbornene-based side-chain polymers were synthesized and studied. In addition, several examples of ambipolar transport moieties were produced by combining hole- (carbazole) and electron- (oxadiazole or triazole) transport groups and examined as both small molecules and as norbornene-based side-chain polymers. UV-visible absorption, fluorescence spectroscopy, cyclic voltammetry, and other methods were used to evaluate the properties of the charge transport materials for use as hole- and/or host layers. It was found that side-functionalization produced polymers with photophysical and electrochemical properties corresponding to the charge transport side groups attached. In addition, several crosslinkable hole-transporting materials (copolymer or small molecule-based) incorporating either benzocyclobutenes, trifluorovinyl ethers, oxetanes, or bis(styrene)s were developed. Thin-films of the crosslinkable materials were shown to be readily insolubilized by thermal treatment permitting the deposition of a subsequent layer from solution onto the crosslinked layer. OLEDs fabricated using several of these materials produced efficient devices. Overall, it was shown that side-chain functionalization can be used to afford solution-processable charge transport polymers where the properties are determined mainly by the side group attached. As such, this approach could be extended to additional examples of charge transport moieties.
3
Koh, Yang-Moon. "Numerical solution of three-dimensional vorticity transport equations." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46971.
Повний текст джерела
4
Peng, Juan. "Transport of multicomponents in a fluid and numerical solution." Ann Arbor, Mich. : ProQuest, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3274550.
Повний текст джерелаАнотація:
Thesis (Ph.D. in Computational and Applied Mathematics)--S.M.U., 2007.Title from PDF title page (viewed Mar. 18, 2008). Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4530. Adviser: Zhangxin Chen. Includes bibliographical references.
5
Jarrett, C. P. "Charge transport in solution-processable organic field-effect transistors." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605062.
Повний текст джерелаАнотація:
The ease of processing conjugated polymers in conjunction with their novel optical and electrical properties has attracted great interest from both theoretical and applied perspectives. There has been particular interest in the development of organic transistors for mass produced low speed electronics. In this dissertation, metal-insulator-semiconductor field-effect transistors (MISFETs) are used to study the physical mechanisms of charge transport in solution-processable conjugated polymers and oligomers. The effect of dopants upon the electrical characteristics of MISFET devices is investigated using a soluble polythiophene derivative. By carefully controlling the doping level, the relationship between the conductivity and field-effect mobility is explored as a function of the dopant level. Temperature dependent measurements of the conductivity for various doping levels are presented, which suggest variable range hopping as a viable mechanism for charge transport. Combining these observations with magnetic susceptibility measurements allows the relationship between the conductivity and field-effect mobility to be modelled within the framework of variable range hopping. The applicability of this model to other systems is discussed in terms of impurities and molecular order. Recently solution-processable polyacetylene has been produced with mesogenic end-groups attached to the end of the chains. These materials are designed in an attempt to improve the molecular order in the films. Charge transport is investigated using MISFET devices by comparing results from materials with and without mesogenic end-groups. The molecular order is explored using electron microscopy and absorption spectroscopy of field-induced charges. Charge transport in precursor-route conjugated materials is studied and shown to result in improvements in device characteristics. In particular, the recent development of a precursor-route to pentacene is utilised and the device characteristics are studied as a function of the conversion conditions. The temperature dependence of the charge mobility is studied for this system and for other conjugated materials. The measurements are compared with those of inorganic systems and discussed in terms of the physical differences between inorganic materials and conjugated polymers.
6
Ekani, Nkodo Axel. "Transport électrophorétique de l'ADN en solution de polymères neutres." Université Louis Pasteur (Strasbourg) (1971-2008), 2001. http://www.theses.fr/2001STR13123.
Повний текст джерела
7
Shakhov, Alexander, Jörg Kärger, and Rustem Valiullin. "Tracing molecular propagation in dextran solution by pulsed field gradient NMR." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-183620.
Повний текст джерела
8
Larisch, Wolfgang. "4 Coupled compartments – an analytical solution for diffusion and reaction kinetics." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-198373.
Повний текст джерела
9
Huang, Huan Van Horn J. David. "Solution studies of uranium(VI) and chromium(III) biological transport." Diss., UMK access, 2006.
Знайти повний текст джерелаАнотація:
Thesis (Ph. D.)--Dept. of Chemistry and School of Pharmacy. University of Missouri--Kansas City, 2006."A dissertation in chemistry and pharmaceutical sciences." Advisor: J. David Van Horn. Typescript. Vita. Leaves 174-177 inserted between leaves 168 and 169. Description based on contents viewed Jan. 29, 2007; title from "catalog record" of the print edition. Includes bibliographical references (leaves 156-176). Online version of the print edition.
10
Yi, Hak-Chae J. "Solution of time-independent inverse problems for linear transport theory /." Thesis, Connect to this title online; UW restricted, 1990. http://hdl.handle.net/1773/10677.
Повний текст джерела
11
Meneau, Aurélie Yvette Béatrice. "Charge transport physics of high-mobility, solution-crystallised molecular semiconductors." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708741.
Повний текст джерела
12
Price, William S. "Applications of pulsed gradient spin-echo NMR diffusion measurements to solution dynamics and organization." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196800.
Повний текст джерелаАнотація:
The study of solution dynamics is a very fundamental area of research with wide ranging importance from physical chemistry through
to the life sciences. A common theme is that the interactions which control the dynamics and organization of solutions are generally very
weak. Translational diffusion provides a non-invasive, direct and natural probe of the dynamics and pulsed gradient spin-echo (PGSE) NMR is a convenient means of measuring diffusion. This paper gives a brief introduction to translational diffusion as a probe of solution dynamics and of the PGSE NMR method before presenting some representative examples illustrating the power of diffusion measurements for elucidating the molecular behaviour. The use of PGSE NMR to study solution dynamics and organization is a very active area of research and a very large
literature already exists, consequently, the coverage of possible applications and the literature cited here is not comprehensive.
13
Zhuo, Yue. "Solution studies of protein complexes of the endocytic machinery : a dissertation /." San Antonio : UTHSC, 2007. http://proquest.umi.com/pqdweb?did=1310415421&sid=2&Fmt=2&clientId=70986&RQT=309&VName=PQD.
Повний текст джерела
14
Guillot, Geneviève. "Transport de macromolécules en solution à travers des membranes poreuses modèles." Paris 11, 1986. http://www.theses.fr/1986PA112297.
Повний текст джерелаАнотація:
Ce travail présente une étude expérimentale du transport de solutions de polymère flexible à travers des membranes à pores fins, dans le cas où polymère et pore sont de taille comparable. Les membranes ont été préparées par irradiation de films de polycarbonate aux ions lourds, une attaque chimique ultérieure révèle les traces latentes d'irradiation en pores cylindriques percés à travers toute l'épaisseur du film (5 à 100 microns), Le rayon de pore (50 à 200 manomètres) a été contrôlé par une observation directe au microscope électronique à balayage, et par des mesures de conductivité et de perméabilité. On a suivi la diffusion de grandes chaînes de polystyrène (masse supérieure au million) en solution dans l'acétate d'éthyle à travers ces membranes, en mesurant la concentration des solutions par spectroscopie d'absorption. Pour des solutions diluées, le coefficient de diffusion obtenu peut être décrit par un modèle sphère dure. Cependant les chaînes de grande taille devant la taille de pore ont une diffusion plus rapide qu'une sphère dure, de plus leur coefficient de diffusion augmente considérablement avec la concentration. Nous attribuons cette accélération à l'augmentation du coefficient de partage des chaînes entre intérieur et extérieur du pore, due à la flexibilité des chaînes qui leur permet de se déformer pour entrer dans le pore, et à la répulsion entre chaînes plus importante à forte concentration, Cet effet a aussi été observé avec des solutions de mélanges de grandes et de petites chaînes de même nature chimique. Des résultats préliminaires d'expériences de filtration sont enfin présentés, concernant la quantité de polymère transportée et l'évolution de la perméabilité de la membrane après filtration. Ils confirment un modèle proposé par S. DAOUDI et F. BROCHARD (1978) d'entraînement des chaînes par déformation à l'entrée des poresAn experimental study of the transport of solutions of flexible polymer chains through membranes with fine pores is presented in this work, for pores and polymers of comparable sizes. Membranes have been prepared by heavy ion irradiation of polycarbonate films, followed by chemical etching which reveals the irradiation latent tracks into cylindrical pores spanning the film (5 to 100 microns). The pore radius has been controlled by direct observation under a scanning electron microscope, and by conductivity and permeability measurements. The diffusion of large polystyrene chains (weights larger than one million) dissolved in ethyl acetate has been followed across these membranes, by measuring the solution concentrations by absorption spectroscopy. For dilute solutions, the measured diffusion coefficient can be described by a hard sphere model. However chains of size larger than the pore size diffuse more rapidly than hard spheres, moreover their diffusion coefficient increases drastically with concentration. We attribute this acceleration to the increase of the partition coefficient between the inside and outside of the pore, due to the chain flexibility which allows the chains to elongate to enter the pore, and to the larger repulsion between chains at higher concentrations. This effect has also been observed with solutions of mixtures of large and small chains of the same chemical composition. Some preliminary results of filtration experiments are also reported, about the amount of transported polymer and about the evolution of the membrane permeability after filtration. They confirm model suggested by S. Daoudi and F. Brochard (1978) for chain transport by elongation under flow at the pore entrance
15
Larisch, Wolfgang. "4 Coupled compartments – an analytical solution for diffusion and reaction kinetics." Diffusion fundamentals 24 (2015) 32, S. 1, 2015. https://ul.qucosa.de/id/qucosa%3A13497.
Повний текст джерела
16
Shakhov, Alexander, Jörg Kärger, and Rustem Valiullin. "Tracing molecular propagation in dextran solution by pulsed field gradient NMR." Diffusion fundamentals 20 (2013) 74, S. 1-2, 2013. https://ul.qucosa.de/id/qucosa%3A13663.
Повний текст джерела
17
Lazaris, Konstantinos A. "High speed transport protocols : an attempt to find the best solution /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA280989.
Повний текст джерела
18
Rehman, Tauseef ur. "Efficient numerical method for solution of L² optimal mass transport problem." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33891.
Повний текст джерелаАнотація:
In this thesis, a novel and efficient numerical method is presented for the computation of the L² optimal mass transport mapping in two and three dimensions. The method uses a direct variational approach. A new projection to the constraint technique has been formulated that can yield a good starting point for the method as well as a second order accurate discretization to the problem. The numerical experiments demonstrate that the algorithm yields accurate results in a relatively small number of iterations that are mesh independent. In the first part of the thesis, the theory and implementation details of the proposed method are presented. These include the reformulation of the Monge-Kantorovich problem using a variational approach and then using a consistent discretization in conjunction with the "discretize-then-optimize" approach to solve the resulting discrete system of differential equations. Advanced numerical methods such as multigrid and adaptive mesh refinement have been employed to solve the linear systems in practical time for even 3D applications. In the second part, the methods efficacy is shown via application to various image processing tasks. These include image registration and morphing. Application of (OMT) to registration is presented in the context of medical imaging and in particular image guided therapy where registration is used to align multiple data sets with each other and with the patient. It is shown that an elastic warping methodology based on the notion of mass transport is quite natural for several medical imaging applications where density can be a key measure of similarity between different data sets e.g. proton density based imagery provided by MR. An application is also presented of the two dimensional optimal mass transport algorithm to compute diffeomorphic correspondence maps between curves for geometric interpolation in an active contour based visual tracking application.
19
Watson, Aaron Michael. "The WN adaptive method for numerical solution of particle transport problems." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3133.
Повний текст джерелаАнотація:
The source and nature, as well as the history of ray-effects, is described. A
benchmark code, using piecewise constant functions in angle and diamond differencing
in space, is derived in order to analyze four sample problems. The results of this
analysis are presented showing the ray effects and how increasing the resolution
(number of angles) eliminates them. The theory of wavelets is introduced and the use of
wavelets in multiresolution analysis is discussed. This multiresolution analysis is
applied to the transport equation, and equations that can be solved to calculate the
coefficients in the wavelet expansion for the angular flux are derived. The use of
thresholding to eliminate wavelet coefficients that are not required to adequately solve a
problem is then discussed. An iterative sweeping algorithm, called the SN-WN method,
is derived to solve the wavelet-based equations. The convergence of the SN-WN method
is discussed. An algorithm for solving the equations is derived, by solving a matrix
within each cell directly for the expansion coefficients. This algorithm is called the CWWN
method. The results of applying the CW-WN method to the benchmark problems are presented. These results show that more research is needed to improve the convergence
of the SN-WN method, and that the CW-WN method is computationally too costly to be
seriously considered.
20
OLIVEIRA, LEONARDO PACHECO DE. "MULTIMODAL TRANSPORT CHAIN MANAGEMENT: INTEGRATED SOLUTION FOR THE FLOW OF ETHANOL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24998@1.
Повний текст джерелаАнотація:
Esta dissertação propõe um modelo de gestão da cadeia de transporte multimodal. O modelo de gestão oferece uma solução para a coordenação e integração da cadeia de transporte, sendo aplicado no estudo de caso referente à empresa Transportes ABC. A empresa em questão estuda a possibilidade de atuar como Operador de Transporte Multimodal - OTM em uma operação visando o escoamento de etanol. O modelo proposto foi construído a partir dos fatores críticos de sucesso. Os fatores foram identificados a partir das características extraídas dos trabalhos sobre transporte multimodal, logística integrada e gestão da cadeia de suprimentos e dos eventos de risco que foram baseados nos mesmos trabalhos e no estudo de caso. É possível observar na estratégia de gestão de risco o foco no desempenho de forma a minimizar os riscos recorrentes da operação contribuindo para reduzir também os riscos de ruptura da operação. Alguns fatores críticos de sucesso devem ser atendidos diretamente pelo OTM, enquanto que outros devem ser atendidos pelos elos operacionais, com a devida coordenação do OTM. Na aplicação do modelo ao estudo de caso, foi confirmada a necessidade de coordenação e integração de toda cadeia pelo OTM no tocante ao caso estudado. Algumas lacunas foram identificadas no sentido sobre o que a empresa visualiza como operações integradas de transporte e como efetivamente deve atuar como OTM na cadeia de transporte multimodal.This thesis proposes a management model of multimodal transport chain. The management model offers a solution to the coordination and integration of the transport chain, being applied in the case study regarding the fictitious company Transportes ABC. The company in question studies the possibility of acting as Multimodal Transport Operator - OTM in an operation aiming the flow of ethanol. The proposed model was constructed based on the critical success factors. The factors were identified from the extracted features of the work on multimodal transport, integrated logistics and supply chain management and risk events that were based on the same work, and in the case study. It is possible to observe in the risk management strategy the focus on performance in order to minimize risks of recurring operation also contribute to reduce the risk of rupture of the operation. Some critical success factors must be met directly by OTM, while others must be met by operational links with the due coordination of the OTM. In applying the model to the case study, it was confirmed the need for coordination and integration of the entire chain by OTM regarding the case studied. Some gaps were identified in the sense of what the company sees as integrated transport operations and how to effectively must act as OTM in the multimodal transport chain.
21
Guillot, Geneviève. "Transport de macromolécules en solution à travers des membranes poreuses modèles." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37599389n.
Повний текст джерела
22
Belashova, Ekaterina. "Électroséparation de solutions complexes pour la production d'acides organiques : phénomènes de transport et réactions aux interfaces membrane / solution." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20146/document.
Повний текст джерелаАнотація:
L'utilisation croissante d'acides organiques dans l'industrie alimentaire, chimique et pharmaceutique entraîne le développement de nouvelles technologies pour leur isolement, séparation et concentration à partir de solutions complexes. Les procédés électro-membranaires constituent une voie prometteuse. Afin d'intensifier ces procédés, il est nécessaire de mieux comprendre les mécanismes de transport de la solution d'ampholytes dans le système électromembranaire souvent couplé à des réactions chimiques. La composition des formes ioniques peut en effet varier en fonction du pH de la solution. Les principaux objectifs de ce travail sont l'étude du comportement des systèmes membranaires contenant des solutions d'ampholytes dans un état d'équilibre (sans force de transfert ou sous très faible courant alternatif), et hors d'équilibre en régime d'électrodialyse (application d'un courant). Dans les deux cas, l'approche comprend une partie expérimentale et une partie théorique de caractérisation de transport de solution complexe. Dans la cadre de la modélisation associée, on a développé un modèle de système membranaire qui permet d'accéder à la distribution des formes d'ampholyte à l'intérieur et à l'extérieur de la membrane en fonction des paramètres externes.Les résultats de la comparaison des données expérimentales et de simulation de systèmes membranaires montre et explique les spécificités des mécanismes de transfert des ions d'ampholyte associés aux changements du pH de la solution au cours de l'électrodialyseThe wide application of organic acids in the food, chemical and pharmaceutical industry is responsible for the increased interest in the development of new technologies for their isolation, separation and concentration from the complex solutions. The electro-membrane processes are promising. The difficulty to understand the transport mechanisms of the amphoteric solution in the electromembrane system is the coupling of chemical reactions: the ionic forms composition can vary depending on the pH of the solution.The main objectives are the study of the behavior of membrane systems containing ampholyte solutions in a steady state (without transfer force or under very low AC) and in a non-equilibrium state such as in electrodialysis regime (applying a current). In both cases, a study includes the experimental and theoretical parts of characterization of the complex solution transport. In the context of modeling a model of the membrane system which can calculate the ampholyte form distribution inside and outside the membrane depending on the external parameters was developed.The comparison of experimental data and results obtained from the simulation of membrane systems containing ampholytes solutions, shows and explains the specific features in the transfer mechanism of ampholyte ions which associated with changes of the solution pH during electrodialysis and, as a consequence, with modification of ampholyte forms
23
Miloš, Regina. "Optimizavimo uždaviniai transporte ir jų sprendimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080924_180548-44400.
Повний текст джерелаАнотація:
Praktinėje žmonių veikloje (transporto sistemoje, valdyme, projektuojant konstrukcijas ir kt.) dažnai reikia rinktis vieną sprendinį iš kelių galimų. Iškyla uždavinys – rasti geriausią sprendinį. Pavyzdžiui, įmonėje reikia taip organizuoti gamybą, kad pelnas, gautas už pagamintą produkciją, būtų didžiausias; reikia taip suplanuoti produktų išvežimą iš siuntimo punktų (sandėlių, bazių) į paskirties punktus (parduotuves, statybos aikšteles ir t. t.), kad bendrosios transportavimo išlaidos būtų mažiausios.
Darbo tikslas išanalizuoti optimizavimo uždavinius transporte, sprendžiant transporto uždavinius įvairiais būdais, naudojant skirtingas programas ir atitinkamus jų modelius. Palyginti programų interfeisus, susipažinti su jų aplinka ir padaryti išvadas, su kuria programa yra patogu ir optimalu spręsti specializuotus uždavinius.
Šio darbo teorinėje dalyje pirmiausiai buvo susipažinta su pagrindinėmis sąvokomis, kurios yra naudojamos nagrinėjant šią problemą. Buvo susipažinta su Solver, WinQSB ir Simplex programomis. Išnagrinėjome, kaip reikia dirbti su Solver, WinQSB ir Simplex programomis, kad būtų galima surasti optimalų sprendinį konkrečių uždavinių transporto sferoje. Darbe taip pat buvo susipažinta su pagrindinėmis Network Modeling programos Transportation Problem (transporto uždavinių sprendimo modulio) – darbo principais, kuris priklauso WinQSB programai.
Šią problemą domėtis bei galvoti kaip ją spręsti ir tobulinti turimas žinias nusprendžiau dirbdama transporto... [toliau žr. visą tekstą]Fairly often it is necessary choose one solution out of several possible ones in the practical human activities (in transport system, management, design of structures, etc.). Naturally, then it is necessary to find the best solution. For example, a company has to arrange its production so as to maximise the profit from the production; product transportation from dispatch points (storehouses, centres) to destination (shops, construction sites, etc.) is to be planned so as to minimise the overall transportation costs. The objective of the work is to analyse the methods of linear programming when solving transportation problems by applying various tools, using different software and their respective models, to compare the software interfaces, get acquainted with their environment and to conclude which of the programmes is the most convenient and optimum for the solution of specific problems. The theoretical part of the work, first of all, introduces the main definitions used in the analysis of the problem. Solver, WinQSB and Simplex software was introduced. It was analysed, how one is to work with Solver, WinQSB and Simplex software to find an optimum solution when dealing with a particular problem of the transport sector. The work also introduces the main principles when working with Transportation Problem module of Network Modelling, which is a part of WinQSB software. I had decided to analyse the problem and improve my knowledge while working in the transport sector – then... [to full text]
24
Loskutov, Valentin, and Vyacheslav Sevriugin. "Analytical solution for the time dependent self-diffusion coefficient of a liquid in a porous medium." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-194287.
Повний текст джерелаАнотація:
The purpose of our work is to attempt to find the analytical expression approximating the experimentally obtained D(t) dependence of molecules of liquids or gases, in porous systems. The statement of the problem is based on the most general representations of self-diffusion processes in porous systems.
25
Lang, Jan, Kateřina Šetková, Veronika Deckerová, Pavel Lhoták, and Jiří Czernek. "Molecular motions of Calix[4]Arene and Thiacalix[4]Arene in solution studied by NMR relaxation." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-194975.
Повний текст джерела
26
Hoffmann, Joachim. "Reactive transport and mineral dissolution, precipitation in porous media : efficient solution algorithms, benchmark computations and existence of global solutions." kostenfrei, 2010. http://d-nb.info/1002480981/34.
Повний текст джерела
27
Olynyk, Thierry. "Coefficients de transport de particules browniennes en solution : approche expérimentale et modélisation." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2001. http://tel.archives-ouvertes.fr/tel-00146787.
Повний текст джерелаАнотація:
Les coefficients d'autodiffusion, le coefficient de diffusion mutuelle ainsi que la conductivité sont des propriétés de transport des ions en solution pouvant être déterminées expérimentalement, par des calculs analytiques ou par simulation de dynamique brownienne.Nous avons comparé ces méthodes pour trois électrolytes en solution aqueuse : le tungtosilicate de sodium avec ou sans sulfate de sodium ajouté, les chlorures de cryptate de potassium et de baryum ; le chlorure de potassium.
La voltammétrie à signaux carrés de potentiel a permis de mesurer le coefficient d'autodiffusion de l'ion tungstosilicate. La RMN impulsionnelle avec gradient de champ a été le moyen de mesurer le coefficient d'autodiffusion des cryptates. La conductivité a été mesurée classiquement par une cellule conductimétrique,
Les systèmes ont été modélisés et leurs propriétés simulées par dynamique brownienne dont les principes sont exposés. Nous montrons comment il est possible d'obtenir les différents coefficients de transport, en particulier le coefficient de diffusion mutuelle qui n'avait pas été calculé jusque là par cette méthode.
Nous avons montré que l'ion tungstosilicate était un bon modèle de particule brownienne et avons déterminé son coefficient d'autodiffusion à dilution infinie en solution aqueuse. Les ions cryptate sont plus difficiles à modéliser. Le calcul du coefficient de diffusion mutuelle par dynamique brownienne a fourni un résultat correct pour le système simple chlorure de potassium et pourrait être étendu à des systèmes plus complexes.
28
Sherwin, Henrietta. "Bike-rail integration as one sustainable transport solution to reduce car dependence." Thesis, University of the West of England, Bristol, 2010. http://eprints.uwe.ac.uk/16859/.
Повний текст джерелаАнотація:
The level of bike-rail integration (combining cycling with rail) in the UK presents an unrealised sustainable mobility potential: two per cent of rail passengers access the rail network by bicycle, contrasting with 40 per cent in the Netherlands. Cycling on its own has distance limitations but in combination with rail it can substitute for longer car journeys and is one means of reducing car dependence. The overall objective of this PhD research project was to understand existing bike-rail integration behaviour in the UK, using as the research location two stations in the South West of England (Bristol Temple Meads and Bristol Parkway), to inform the design, development and implementation of initiatives to increase its incidence. It therefore had two distinct research phases: an exploratory phase and an action research phase. The exploratory phase demonstrated that bike-rail integrators were mainly motivated by saving time or money and taking exercise. The majority were male, in their thirties, in full-time employment and cycled on average 3.7 km to the station. These data in conjunction with a conceptual „ecological‟ model developed from a critical review of behaviour change theory were used to inform the design and implementation of a pay-as-you-go self-hire cycle network (Hourbike) and an intervention to attract car drivers to switch to rail with either walking or cycling access. In the first year of Hourbike, seven per cent of users had never really cycled before and one per cent of car drivers responded to the opportunity to try rail with walking or cycling access rendering rich qualitative data from non-users about the attractors and barriers to bike-rail integration. The process of incorporating theory into practice is described providing useful insights for future interventions which are discussed in the light of theory. Opportunities are identified in the context of the national policy to implement station travel plans which emerged in the latter phases of the research.
29
Stokes, Paul. "Controlled assembly and electronic transport studies of solution processed carbon nanotube devices." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4549.
Повний текст джерелаАнотація:
Developing techniques for the parallel fabrication of Complementary Metal Oxide Semiconductor (CMOS) compatible single walled carbon nanotube (SWNT) electronic devices is of great importance for nanoelectronic applications. In this thesis, solution processed SWNTs in combination with AC dielectrophoresis (DEP) were utilized to fabricate CMOS compatible SWNT field effect transistors (FETs) and single electron transistors (SETs) with high yield and their detailed electronic transport properties were studied. Solution processing of SWNTs is attractive not only for the high throughput and parallel manufacturing of SWNT devices but also due to the ease of processing at room temperature, and compatibility with various substrates. However, it is generally believed that solution processing introduces defects and can degrade electronic transport properties. The results presented in this dissertation show that devices assembled from stable solutions of SWNT can give rise to high quality FET devices at room temperature and relatively clean SET behavior at low temperature. This is a strong indication that there are no or few intrinsic defects in the SWNTs. The dissertation will also discuss the controlled fabrication of size tunable SWNT SET devices using a novel mechanical template approach which offers a route towards the parallel fabrication of room temperature SET devices. The approach is based on the formation of two tunnel barriers created in a SWNT a distance L apart by bending the SWNT at the edge of a local Al/Al2O3 bottom gate. The local gate tunes individual electrons one by one in the device and defines the size of the quantum dot though its width. By tuning both the back gate and local gate, it is possible to tune the transparency of tunnel barriers and the size of the quantum dot further. Detailed transport spectroscopy of these devices will be presented.ID: 028197673; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2010.; Includes bibliographical references.
Ph.D.
Doctorate
Department of Physics
Sciences
30
Wijeyasinghe, Nilushi. "Copper pseudohalides as solution-processable hole-transport materials for opto/electronic applications." Thesis, Imperial College London, 2018. http://hdl.handle.net/10044/1/64916.
Повний текст джерелаАнотація:
This thesis presents the development of novel copper pseudohalide hole-transport layers (HTLs) for thin-film transistors (TFTs), organic photovoltaic (OPV) cells, perovskite solar cells (PSCs), and organic light-emitting diodes (OLEDs). Their impact on device performance is assessed relative to two reference HTLs: a conventional polymer HTL, and copper(I) thiocyanate (CuSCN) deposited via an n-alkyl sulphide solvent (diethyl sulphide, DES). The first experimental chapter demonstrates aqueous ammonia (NH3 (aq)) as a novel processing solvent for CuSCN, which produces HTLs with greatly enhanced electronic and structural properties. CuSCN/NH3 HTLs exhibit exceptional anode planarisation properties and mean field-effect hole mobility (μ) of 0.05 cm2 V-1 s-1. OPV cells and PSCs employing a CuSCN/NH3 HTL consistently outperform devices utilising a reference HTL by achieving maximum power conversion efficiency of 10.7% (OPV) and 17.5% (PSC). Next, a fluorinated fullerene (C60F48) is utilised as a p-dopant for CuSCN/DES. Analysis of material and device characterisation data reveal strong evidence of a successful p-doping process. Mean μ of 0.12 cm2 V-1 s-1 is measured in TFTs based on CuSCN:C60F48 (0.5 mol%), which is a twelvefold increase relative to pristine CuSCN. Additional advantages include an order of magnitude reduction in contact resistance, a dramatic increase in bias stability, and a change in the dominant hole-transport mechanism from trap limited conduction to percolation conduction. Optimised CuSCN:C60F48 HTLs also outperform reference HTLs in OPV applications; substantial increases in fill factor and device yield are observed. Finally, the third experimental chapter reports on a novel wide-bandgap (≥3.1 eV) p-type semiconductor, copper(I) selenocyanate (CuSeCN). Its electronic, structural and optical properties are predicted using density functional theory calculations and verified using numerous experimental techniques. CuSeCN/DES layers annealed at 140 ̊C exhibit excellent performance in TFTs, OPV cells, and OLEDs. Hence, this thesis demonstrates the tremendous potential of copper pseudohalides as universal HTLs for opto/electronics.
31
Olynyk, Thierry. "Coefficients de transport de particules browniennes en solution : approche experimentale et modelisation." Paris 6, 2001. https://tel.archives-ouvertes.fr/tel-00146787.
Повний текст джерелаАнотація:
Les coefficients d'autodiffusion, le coefficient de diffusion mutuelle ainsi que la conductivite sont des proprietes de transport des ions en solution pouvant etre determinees experimentalement, par des calculs analytiques ou par simulation de dynamique brownienne. Nous avons compare ces methodes pour trois electrolytes en solution aqueuse : le tungstosilicate de sodium avec ou sans sulfate de sodium ajoute ; les chlorures de cryptate de potassium et de baryum ; le chlorure de potassium. La voltammetrie a signaux carres de potentiel a permis de mesurer le coefficient d'autodiffusion de l'ion tungstosilicate. La rmn impulsionnelle avec gradient de champ a ete le moyen de mesurer le coefficient d'autodiffusion des cryptates. La conductivite a ete mesuree classiquement par une cellule conductimetrique. Les systemes ont ete modelises et leurs proprietes simulees par dynamique brownienne dont les principes sont exposes. Nous montrons comment il est possible d'obtenir les differents coefficients de transport, en particulier le coefficient de diffusion mutuelle qui n'avait pas ete calcule jusque la par cette methode. Nous avons montre que l'ion tungstosilicate etait un bon modele de particule brownienne et avons determine son coefficient d'autodiffusion a dilution infinie en solution aqueuse. Les ions cryptate sont plus difficiles a modeliser. Le calcul du coefficient de diffusion mutuelle par dynamique brownienne a fourni un resultat correct pour le systeme simple chlorure de potassium et pourrait etre etendu a des systemes plus complexes.
32
Martin, Sébastien. "Mécanismes de sorption et d'oxydoréduction à l'interface oxyde/solution : couplage chimie / transport." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S157.
Повний текст джерелаАнотація:
Au vu de l'omniprésence des oxydes de fer dans le milieu naturel, et en particulier la goethite et l'hématite qui sont les formes les plus stables, mais aussi de la prolifération des contaminants émergents dans l'environnement, comme les fluoroquinolones, notre objectif a été d'étudier leur réactivité et de définir les mécanismes de sorption et d'oxydoréduction à l'interface oxyde/solution dans des conditions statiques (batch) et hydrodynamiques contrôlées (colonne) en couplant une étude macroscopique (techniques chromatographiques, LC/MS, LC/UV) avec une approche microscopique (spectroscopie vibrationnelle et XPS) et de modélisation mécanistique (TPM et CD-MUSIC). Ces travaux mettent en évidence les principaux mécanismes responsables de la transformation des molécules organiques à la surface d'un oxyde de fer, et donc fournissent des informations nécessaires à la compréhension du devenir des contaminants émergents dans l'environnementGiven the ubiquity of iron oxides in environmental settings, particularly goethite and hematite, the most stable forms, but also the proliferation of emerging contaminants, such as fluoroquinolones, in the environment, our goal was to study their reactivity and describe mechanisms of sorption and redox at oxide /solution interfaces in static batch) and hydrodynamic conditions (column) by coupling a macroscopic study (LC/MS, LC/UV) with a microscopic/molecular approach (vibrational spectroscopy and XPS) and mechanistic modeling (TPM and CD-MUSIC).. These works highlight the main mechanisms responsible of the transformation of organic molecules on iron oxide surfaces and thus provide valuable information necessary for the understanding of the fate of emerging contaminants in the environment
33
Granier, Jean-Marie. "Transport du carbone inorganique en solution expérimentation et modélisation à différentes échelles... /." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37614037w.
Повний текст джерела
34
Price, William S. "Applications of pulsed gradient spin-echo NMR diffusion measurements to solution dynamics and organization." Diffusion fundamentals 2 (2005) 112, S. 1-19, 2005. https://ul.qucosa.de/id/qucosa%3A14451.
Повний текст джерелаАнотація:
The study of solution dynamics is a very fundamental area of research with wide ranging importance from physical chemistry through
to the life sciences. A common theme is that the interactions which control the dynamics and organization of solutions are generally very
weak. Translational diffusion provides a non-invasive, direct and natural probe of the dynamics and pulsed gradient spin-echo (PGSE) NMR is a convenient means of measuring diffusion. This paper gives a brief introduction to translational diffusion as a probe of solution dynamics and of the PGSE NMR method before presenting some representative examples illustrating the power of diffusion measurements for elucidating the molecular behaviour. The use of PGSE NMR to study solution dynamics and organization is a very active area of research and a very large
literature already exists, consequently, the coverage of possible applications and the literature cited here is not comprehensive.
35
James, Ronald Arthur. "Onsager Heat of Transport at the Liquid-Vapour Interface of Glycerol-Water Solutions." Thesis, University of Canterbury. Chemistry, 2007. http://hdl.handle.net/10092/1361.
Повний текст джерелаАнотація:
The Onsager heat of transport, Q*, has been measured for water vapour above glycerol-water solutions (75 % to 94.5 % glycerol) over a temperature range of -46 to -32 ℃. For solutions of concentrations 80 % and above, Q* varied from 5.41 kJ mol-1 ± 0.97 to 17.37 kJ mol-1 ± 2.61, consistent with previous results for aniline and n-heptanol. The dissociation of glycerol-water complexes was not rate determining, as was the case for sulfuric acid-water solutions, and therefore the glycerol-water system is a better two component system analog for comparison with the CO2-water system than the sulfuric acid-water system.
36
Sahabana, Maïdadi. "Les autobus en site propre intégral, une solution à la crise des transports dans les grandes agglomérations subsahariennes." Phd thesis, Université Lumière - Lyon II, 2006. http://tel.archives-ouvertes.fr/tel-00104403.
Повний текст джерелаАнотація:
Malgré un ralentissement du rythme, la population des grandes agglomérations subsahariennes continue de croître. Outre la génération de nouveaux besoins en déplacements, cette croissance se traduit par un rallongement des distances intra-urbaines. Elle conduit à une concentration des déplacements longue distance sur un nombre réduit d'axes de liaison centre/périphérie. Le transport artisanal, qui assure l'essentiel des déplacements mécanisés dans les villes africaines s'avère insuffisant pour satisfaire les niveaux de demande sur les axes les plus sollicités et est incapable d'assurer une bonne couverture spatiale des aires urbaines étendues. L'aménagement de systèmes d'autobus en site propre intégral – option technique et organisationnelle développée par certaines villes latino-américaines – constitue une solution à la crise des transports urbains subsahariens. Contrairement aux systèmes ferroviaires, sa mise en place et son exploitation sont financièrement accessibles aux agglomérations subsahariennes. Le niveau d'investissement qu'exige la construction de tels équipements est accessible à condition d'être pris en charge par la puissance publique et la durabilité du service fourni est envisageable à travers une exploitation entrepreneuriale et privée. Les autobus en site propre intégral, en tant que système de transport urbain de masse, sont d'abord une réponse efficace aux liaisons centre/périphérie à forte demande dans les agglomérations subsahariennes. Grâce à un usage optimisé des infrastructures, des véhicules de transport collectif et un recours à des mesures d'aide à l'exploitation, ce système permet de transporter un grand nombre de passagers tout en minimisant les temps de déplacement et les externalités négatives générées par les transports urbains. Mais surtout, un système d'autobus en site propre intégral introduit une logique de hiérarchisation et de complémentarité de l'offre de transport urbain. Il impose ainsi une vision d'ensemble dans l'organisation des transports urbains. Parce qu'il représente une amélioration qualitative de la mobilité urbaine et un marquage physique fort de l'espace urbain sur une durée relativement longue, il constitue un levier, d'une part, pour une remise en cause du cadre organisationnel et réglementaire défaillant des transports urbains subsahariens, d'autre part, pour une restructuration de l'offre actuelle. Les autobus en site propre intégral représentent donc un moyen de mettre en place une offre adaptée aux flux de déplacements propres aux grandes agglomérations, entre des liaisons centre/périphérie très sollicitées et d'autres qui le sont moins, et d'organiser une meilleure complémentarité entre ces différentes échelles.
37
FELDER, Christophe. "Transport d'une solution saline en cellule de Hele-Shaw - Expériences et simulations numériques." Phd thesis, Institut National Polytechnique de Lorraine - INPL, 2003. http://tel.archives-ouvertes.fr/tel-00006120.
Повний текст джерелаАнотація:
Afin d'étudier l'évolution spatio-temporelle d'un polluant miscible à l'eau et non réactif dans un milieu poreux saturé, un modèle de laboratoire (une cellule de Hele-Shaw transparente) a été développé. La conception de ce dispositif, les plaques sont réalisées en verre optique, a permis de mettre au point une méthode globale et non intrusive de mesure de la concentration dans la zone de mélange. Cette méthode est basée sur les propriétés d'absorption de la lumière par un colorant marquant la solution injectée. L'analogie entre une cellule de Hele-Shaw et un milieu poreux est basée sur la possibilité d'exprimer la vitesse moyenne de l'écoulement entre les deux plaques par la loi de Darcy. En outre, le transport moyen d'un traceur peut être décrit avec un tenseur de dispersion (dispersion de Taylor). Dans le cas d'un fluide hétérogène (e.g. : contrastes de masse volumique ou de viscosité), les conditions d'analogie sont obtenues par une approche analytique de type développement asymptotique et homogénéisation pour prendre en compte la variation de la masse volumique et de la viscosité dynamique en fonction de la concentration. Une nouvelle forme du tenseur de dispersion est établie. Suivant le débit volumique et la fraction massique en sel de la solution injectée dans le milieu homogène, des expériences qualitativement reproductibles montrent que le panache se propage sous la forme d'un ou de deux doigts. Un critère empirique, basé sur le rapport entre la vitesse gravitationnelle et celle à l'injection, est formulé pour prédire le type de propagation. Les simulations, réalisées avec un code numérique développé au laboratoire et incluant la nouvelle forme du tenseur de dispersion, permettent : (i) de reproduire de manière satisfaisante les résultats expérimentaux obtenus en milieu homogène et hétérogène et (ii) d'analyser les influences de la diffusion, de la géométrie de l'injection et du type de régime de dispersion sur les distributions numériques du soluté.
38
au, adt@murdoch edu, and Chamlong Poboon. "Anatomy of a traffic disaster : towards a sustainable solution to Bangkok's transport problems." Murdoch University, 1997. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20061122.142856.
Повний текст джерелаАнотація:
Bangkok's extreme traffic problems have been traditionally explained in terms of a lack
of road infrastructure and policy responses for many years have almost exclusively
stressed road investment to the exclusion of all other forms of transport infrastructure
development. This thesis questions this interpretation of the traffic problem and its
chief policy response: building still more roads. It suggests that in order to effectively
analyse Bangkok's traffic predicament and to formulate more sustainable responses to
the crisis, an understanding is required of Bangkok's land use and transport
development, as well as a systematic and detailed perspective on the similarities and
differences between Bangkok and many other cities around the world, particularly
those in Asia.
This thesis suggests that Bangkok has passed through three key periods: a water-based
transport and walking period, a transport modernisation period and a motorisation
period. In each period up to motorisation Bangkok appeared to maintain a harmonious
relationship between its high density, mixed use urban form, ideally suited to nonmotorised
modes and to public transport. Even in the motorisation period, high
density, mixed use development has mostly followed major road corridors and
remains well-suited to much higher public transport and non-motorised mode use than
currently exist. However, in this period, rapidly rising motor vehicle ownership and use
began to come into conflict with the city's pre-automobile form. Road infrastructure
could not be built fast enough to keep pace with traffic growth, despite almost
exclusive commitment of resources to roads. High capacity public transport systems,
including rail, renewed water transport and busways failed to materialise to help curb
the motorisation process and to provide much needed relief on the roads. A basic
conflict or mismatch between urban form and transport began to emerge, leaving the
city ill-equipped to cope with the automobile and subject to large environmental, social
and economic impacts from congestion.
The thesis argues that while Bangkok's per capita road supply is low in an
international sense, it is not atypical for an Asian city and road availability per hectare
is similar to many other cities around the world. Likewise, common arguments about
an inadequate road hierarchy are systematically analysed and are shown to be
insufficient in explaining Bangkok's present crisis. The thesis thus suggests that
attempting to tackle the traffic problem through an intensification of road building
efforts will not provide the relief sought, but will only exacerbate the traffic impacts
which are shown to be already at the limits of international experience.
The international comparison of Bangkok with other cities, highlighting basic
similarities and differences in land use and transport features, continues to build upon
this argument. It shows that Bangkok lies at one extreme in many transport
characteristics such as the amount of travel per hectare, and within the Asian cities, it
is very high in vehicle ownership and use and energy use, comparatively low in public
transport use and very low in non-motorised modes. The thesis suggests that in
physical planning terms, Bangkok's traffic crisis appears to stem from a set of
mismatches between its transport patterns, urban form and transport infrastructure.
These mismatches are between: (1) vehicle use and urban form: higher levels of private
vehicle use than can be properly accommodated in its dense, tightly woven urban
fabric; (2) vehicle use and road supply: levels of private vehicle use which are
incompatible with its road availability and which are uncharacteristically high
compared to other Asian cities; (3) transit use, urban form and road supply: lower
levels of overall transit use than would be expected in a city of its urban form and road
availability; (4) transit infrastructure, urban form and road supply: a public transport
infrastructure which is inadequate to meet the demands for transit movement inherent
in such a dense city, particularly a lack of rail infrastructure; (5) non-motorised modes
and urban form: levels of non-motorised mode use which are uncharacteristically low
for such a dense, mixed use urban fabric. These mismatches are mainly the consequence
of a long series of inappropriate and ineffective transport policies and investments
which are biased towards private transport and which have at least in part arisen
from narrow and outdated transport planning processes.
In order for transport planning in Bangkok to address the suggested roots of the crisis,
the thesis contends that at least two key constraints would have to be dealt with: the
traditional urban transport planning process and the institutional fragmentation in
transport policy and implementation. Notwithstanding, there are forces pushing in the
direction of change and these are examined in terms of the growing global and local
trends towards sustainability, community outrage over traffic and the role of NGOs.
Based on these findings, this thesis provides a case for a series of policies to help deal
with Bangkok's traffic disaster. In line with global trends towards sustainability as an
organising principle for urban policy development, these policies are offered within a
framework of developing a more sustainable transport system in Bangkok. The policies
suggested cover priority to public transport infrastructure development, transitoriented,
mixed land use development, transport demand management, improvement
of waterway transportation, facilitation of walking and cycling and institutional
reform of Bangkok's transport decision making structure. Opportunities for further
complementary research are suggested.
39
O'Malley, Benedict John. "Parallel, hierarchical solution algorithms for diffusion synthetic acceleration of the neutron transport equation." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/58934.
Повний текст джерелаАнотація:
The ability to obtain fast and accurate solutions of the neutron transport equation is of great importance for various reactor physics and radiation shielding applications. This thesis first presents an overview of the techniques used to solve the neutron transport equation using discontinuous Galerkin finite element methods. It then presents two sets of techniques which aim to improve the effectiveness of a neutron transport code and provides various computational results to support their effectiveness. The first methods studied are two preconditioners designed to accelerate the solution of the neutron diffusion equation which in turn is used to accelerate the neutron transport equation using diffusion synthetic acceleration. They are first presented in a form appropriate for solving finite element problems using first-order basis functions, and then expanded so that they may be used on problems containing second and higher-order basis functions. The second study is for sets of basis functions for pyramid finite elements used in the solution of neutron transport and neutron diffusion problems, demonstrating the effectiveness of these elements in comparison to other element types. This thesis provides substantial evidence for the effectiveness of the methods described alongside an analysis of where their use is appropriate. Numerous computational examples are used, including several reactor physics and radiation shielding benchmark problems obtained from benchmark specifications. These serve to demonstrate the strengths and in some cases the weaknesses of the techniques presented. The methods presented have significant practical applications in the fields of reactor physics and radiation shielding.
40
Le, Coz Yannick L. "Semiconductor device simulation : a spectral method for solution of the Boltzmann transport equation." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14482.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.Title as it appeared in M.I.T. Graduate List, February 1988: Simulation of semiconductor devices : a spectral method for solution of the Boltzmann transport equation.
Includes bibliographical references (leaves 193-195).
by Yannick L. Le Coz.
Ph.D.
41
Vuilleumier, Rodolphe. "Transport et spectroscopie du proton en solution aqueuse : une etude de dynamique moleculaire." Paris 6, 1998. http://www.theses.fr/1998PA066644.
Повний текст джерелаАнотація:
La mobilite anormale d'un proton dans l'eau est attribuee traditionnellement a une succession de reactions de transfert de proton entre molecules d'eau voisines (mecanisme dit de grotthus). Pour etudier la nature microscopique du proton hydrate et son mecanisme de transport, nous introduisons un modele semi-empirique de liaison de valence (ajuste sur des calculs ab-initio). Le modele permet de tenir compte d'un nombre n arbitraire d'etats de valence pour le systeme proton + eau et l'etat electronique fondamental est obtenu par diagonalisation d'une matrice d'interaction n n. Le champ de force resultant autorise la delocalisation de la charge du proton sur plusieurs molecules environnantes et la brisure et formation successives des liaisons o-h +. Nous avons applique ce champ de force pour etudier, avec un cout numerique faible, la structure et la dynamique des petits agregats d'eau protones ainsi que la dynamique de transfert d'un proton dans l'eau liquide. Le caractere quantique du proton est inclus dans les parametres du modele a partir d'un calcul d'integrales de chemin prealable. A la lumiere des simulations, le mecanisme de transfert du proton peut etre interprete comme la translocation d'une structure h 5o 2 + transitoire le long du reseau hydrogene de l'eau plutot que comme une simple suite de reaction h 3o + + h 2o h 2o + h 3o +. Le spectre d'absorption infrarouge tres large qui caracterise la presence de proton en exces dans l'eau est aussi calcule et analyse. Les bandes autour de 1200 et 1800 cm - 1 sont attribuees a un melange de modes de pliage et d'elongation asymetrique du complexes h 5o 2 + et le continuum d'absorption entre 2000 et 3000 cm - 1 provient de l'interconversion entre la forme delocalisee, h 5o 2 +, et localisee (h 3o +) du proton hydrate qui est induite par les fluctuations du milieu aqueux environnant.
42
Stenhouwer, Richard Charles. "Transport and adsorption interactions of band applied anhydrous ammonia and potassium cholride solution /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487681788252882.
Повний текст джерела
43
Rocheleau, Joshua. "An Analytical Nodal Discrete Ordinates Solution to the Transport Equation in Cartesian Geometry." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587112226198162.
Повний текст джерела
44
Felder, Christophe. "Transport d'une solution saline en cellule de Hele-Shaw : expériences et simulations numériques." Vandoeuvre-les-Nancy, INPL, 2003. http://www.theses.fr/2003INPL067N.
Повний текст джерелаАнотація:
Afin d'étudier l'évolution spatio-temporelle d'un polluant miscible à l'eau et non réactif dans un milieu poreux saturé, un modèle de laboratoire (une cellule de Hele-Shaw transparente) a été développé. Une méthode globale et non intrusive a été mis au point pour mesurer la concentration dans la zone de mélange. L'analogie entre cellule de Hele-Shaw et milieu poreux est obtenue par développement asymptotique et homogénéisation pour prendre en compte la variation de la masse volumique et de la viscosité dynamique en fonction de la concentration. Une nouvelle forme du tenseur de dispersion est établie. Les expériences reproductibles montrent que le panache se propage sous la forme d'un ou de deux doigts. Un critère, basé sur le rapport entre la vitesse gravitationnelle et celle à l'injection, est formulé pour prédire le type de propagation. Les simulations, réalisées avec un code numérique incluant la nouvelle forme du tenseur de dispersion, reproduisent les résultats expérimentauxTo study the spatio-temporal evolution of a miscible and non-reactive contaminant into a saturated porous media, a laboratory mode! (a transparent Hele-Shaw cell) was developed. The carrying out of the experimental set-up, the plates are made of optical glass, allowed to elaborate a global and non-intrusive method to measure concentration in the mixing zone. This method is based on light absorption properties by dye marking injected solution
45
Oliveira, Anabela Pacheco de Pacheco de Oliveira Anabela De Oliveira Anabela Pacheco. "A comparison of Eulerian-Lagrangian methods for the solution of the transport equation /." Full text open access at:, 1994. http://content.ohsu.edu/u?/etd,208.
Повний текст джерела
46
Baker, Randal Scott. "A fully coupled Monte Carlo/discrete ordinates solution to the neutron transport equation." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185233.
Повний текст джерелаАнотація:
The neutron transport equation is solved by a hybrid method that iteratively couples regions where deterministic (S(N)) and stochastic (Monte Carlo) methods are applied. Unlike previous hybrid methods, the Monte Carlo and S(N) regions are fully coupled in the sense that no assumption is made about geometrical separation or decoupling. The hybrid method provides a new means of solving problems involving both optically thick and optically thin regions that neither Monte Carlo nor S(N) is well suited for by themselves. The fully coupled Monte Carlo/S(N) technique consists of defining spatial and/or energy regions of a problem in which either a Monte Carlo calculation or an S(N) calculation is to be performed. The Monte Carlo region may comprise the entire spatial region (with vacuum boundary conditions) for selected energy groups, or may consist of a rectangular areas that is either completely or partially embedded in an arbitrary S(N) region. The Monte Carlo and S(N) regions are then connected through the common angular boundary fluxes, which are determined iteratively using the response matrix technique, and volumetric sources. The hybrid method has been implemented in the S(N) code TWODANT by adding special-purpose Monte Carlo subroutines to calculate the response matrices and volumetric sources, and linkage subroutines to carry out the interface flux iterations. The common angular boundary fluxes are included in the S(N) code as interior boundary sources, leaving the logic for the solution of the transport flux unchanged, while, with minor modifications, the diffusion synthetic accelerator remains effective in accelerating the S(N) calculations. The special-purpose Monte Carlo routines used are essentially analog, with few variance reduction techniques employed. However, the routines have been successfully vectorized, with approximately a factor of five increase in speed over the non-vectorized version. The hybrid method is capable of solving forward, inhomogeneous source problems in X - Y and R - Z geometries. This capability includes multigroup problems involving upscatter and fission in non-highly multiplying (k(eff) ≤ .8) systems. The hybrid method has been applied to several simple test problems with good results.
47
Bennett, Paul. "Evaluation of the solute transport characteristics of surcharged manholes using a RANS solution." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/3098/.
Повний текст джерелаАнотація:
Urban drainage networks contain a large number of structures; the most common of which is a manhole. Previous studies investigating solute transport through manholes identified a threshold level of surcharge at which the hydraulic conditions in the manholes sharply altered. At high levels of surcharge, a dead zone formed above the main jet, potentially retaining solute for later discharge. This phenomenon could have significant impacts on the results obtained from 1D urban drainage network models which only consider pure advection. Previous research (including other CFD based studies) concentrated on steady flow conditions through these structures which are not thought to be representative of the dynamic flow conditions experienced in practice. During large storm events, the capacity of combined sewer networks may be exceeded. This leads to the discharge of untreated sewage to receiving watercourses. Discharges such as these are governed by legislation and, therefore, an understanding of pollutant transfer through urban drainage networks is required. Using existing laboratory and Computational Fluid Dynamics (CFD) data, this study produced a primary and secondary validated methodology for meshing and modelling manholes using CFD. This was then extended to free-surface multiphase modelling allowing for more realistic unsteady conditions to be considered. This included an in-depth comparison of suitable turbulence models and solute-modelling options. It was found that, whilst it was possible to model multiphase free-surface flow within such a structure, it was unnecessarily computationally expensive as temporal changes in the flow field are rapid when compared with a practical time-step for use with 1D models. The validated modelling methodology was then used to recreate the original study that identified the hydraulic threshold. This included a selection of manholes with a range of inlet to manhole diameter ratios. However, this was extended further to include manholes with a ratio less than five (commonly found in UK sewer systems). It was shown that the hydraulic threshold broke down below this limit, removing the need for this to be modelled in 1D systems.
48
Poboon, Chamlong. "Anatomy of a traffic disaster: towards a sustainable solution to Bangkok's transport problems." Thesis, Poboon, Chamlong (1997) Anatomy of a traffic disaster: towards a sustainable solution to Bangkok's transport problems. PhD thesis, Murdoch University, 1997. https://researchrepository.murdoch.edu.au/id/eprint/263/.
Повний текст джерелаАнотація:
Bangkok's extreme traffic problems have been traditionally explained in terms of a lack of road infrastructure and policy responses for many years have almost exclusively stressed road investment to the exclusion of all other forms of transport infrastructure development. This thesis questions this interpretation of the traffic problem and its chief policy response: building still more roads. It suggests that in order to effectively analyse Bangkok's traffic predicament and to formulate more sustainable responses to the crisis, an understanding is required of Bangkok's land use and transport development, as well as a systematic and detailed perspective on the similarities and differences between Bangkok and many other cities around the world, particularly those in Asia.
This thesis suggests that Bangkok has passed through three key periods: a water-based transport and walking period, a transport modernisation period and a motorisation period. In each period up to motorisation Bangkok appeared to maintain a harmonious relationship between its high density, mixed use urban form, ideally suited to nonmotorised modes and to public transport. Even in the motorisation period, high density, mixed use development has mostly followed major road corridors and remains well-suited to much higher public transport and non-motorised mode use than currently exist. However, in this period, rapidly rising motor vehicle ownership and use began to come into conflict with the city's pre-automobile form. Road infrastructure could not be built fast enough to keep pace with traffic growth, despite almost exclusive commitment of resources to roads. High capacity public transport systems, including rail, renewed water transport and busways failed to materialise to help curb the motorisation process and to provide much needed relief on the roads. A basic conflict or mismatch between urban form and transport began to emerge, leaving the city ill-equipped to cope with the automobile and subject to large environmental, social and economic impacts from congestion.
The thesis argues that while Bangkok's per capita road supply is low in an international sense, it is not atypical for an Asian city and road availability per hectare is similar to many other cities around the world. Likewise, com mon arguments about an inadequate road hierarchy are systematically analysed and are shown to be insufficient in explaining Bangkok's present crisis. The thesis thus suggests that attempting to tackle the traffic problem through an intensification of road building efforts will not provide the relief sought, but will only exacerbate the traffic impacts which are shown to be already at the limits of international experience.
The international comparison of Bangkok with other cities, highlighting basic similarities and differences in land use and transport features, continues to build upon this argument. It shows that Bangkok lies at one extreme in many transport characteristics such as the amount of travel per hectare, and within the Asian cities, it is very high in vehicle ownership and use and energy use, comparatively low in public transport use and very low in non-motorised modes. The thesis suggests that in physical planning terms, Bangkok's traffic crisis appears to stem from a set of mismatches between its transport patterns, urban form and transport infrastructure. These mismatches are between: (1) vehicle use and urban form: higher levels of private vehicle use than can be properly accommodated in its dense, tightly woven urban fabric; (2) vehicle use and road supply: levels of private vehicle use which are incompatible with its road availability and which are uncharacteristically high compared to other Asian cities; (3) transit use, urban form and road supply: lower levels of overall transit use than would be expected in a city of its urban form and road availability; (4) transit infrastructure, urban form and road supply: a public transport infrastructure which is inadequate to meet the demands for transit movement inherent in such a dense city, particularly a lack of rail infrastructure; (5) non-motorised modes and urban form: levels of non-motorised mode use which are uncharacteristically low for such a dense, mixed use urban fabric. These mismatches are mainly the consequence of a long series of inappropriate and ineffective transport policies and investments which are biased towards private transport and which have at least in part arisen from narrow and outdated transport planning processes.
In order for transport planning in Bangkok to address the suggested roots of the crisis, the thesis contends that at least two key constraints would have to be dealt with: the traditional urban transport planning process and the institutional fragmentation in transport policy and implementation. Notwithstanding, there are forces pushing in the direction of change and these are examined in terms of the growing global and local trends towards sustainability, community outrage over traffic and the role of NGOs.
Based on these findings, this thesis provides a case for a series of policies to help deal with Bangkok's traffic disaster. In line with global trends towards sustainability as an organising principle for urban policy development, these policies are offered within a framework of developing a more sustainable transport system in Bangkok. The policies suggested cover priority to public transport infrastructure development, transitoriented,mixed land use development, transport demand management, improvement of waterway transportation, facilitation of walking and cycling and institutional reform of Bangkok's transport decision making structure. Opportunities for further complementary research are suggested.
49
Poboon, Chamlong. "Anatomy of a traffic disaster : towards a sustainable solution to Bangkok's transport problems /." Poboon, Chamlong (1997) Anatomy of a traffic disaster: towards a sustainable solution to Bangkok's transport problems. PhD thesis, Murdoch University, 1997. http://researchrepository.murdoch.edu.au/263/.
Повний текст джерелаАнотація:
Bangkok's extreme traffic problems have been traditionally explained in terms of a lack of road infrastructure and policy responses for many years have almost exclusively stressed road investment to the exclusion of all other forms of transport infrastructure development. This thesis questions this interpretation of the traffic problem and its chief policy response: building still more roads. It suggests that in order to effectively analyse Bangkok's traffic predicament and to formulate more sustainable responses to the crisis, an understanding is required of Bangkok's land use and transport development, as well as a systematic and detailed perspective on the similarities and differences between Bangkok and many other cities around the world, particularly those in Asia.
This thesis suggests that Bangkok has passed through three key periods: a water-based transport and walking period, a transport modernisation period and a motorisation period. In each period up to motorisation Bangkok appeared to maintain a harmonious relationship between its high density, mixed use urban form, ideally suited to nonmotorised modes and to public transport. Even in the motorisation period, high density, mixed use development has mostly followed major road corridors and remains well-suited to much higher public transport and non-motorised mode use than currently exist. However, in this period, rapidly rising motor vehicle ownership and use began to come into conflict with the city's pre-automobile form. Road infrastructure could not be built fast enough to keep pace with traffic growth, despite almost exclusive commitment of resources to roads. High capacity public transport systems, including rail, renewed water transport and busways failed to materialise to help curb the motorisation process and to provide much needed relief on the roads. A basic conflict or mismatch between urban form and transport began to emerge, leaving the city ill-equipped to cope with the automobile and subject to large environmental, social and economic impacts from congestion.
The thesis argues that while Bangkok's per capita road supply is low in an international sense, it is not atypical for an Asian city and road availability per hectare is similar to many other cities around the world. Likewise, com mon arguments about an inadequate road hierarchy are systematically analysed and are shown to be insufficient in explaining Bangkok's present crisis. The thesis thus suggests that attempting to tackle the traffic problem through an intensification of road building efforts will not provide the relief sought, but will only exacerbate the traffic impacts which are shown to be already at the limits of international experience.
The international comparison of Bangkok with other cities, highlighting basic similarities and differences in land use and transport features, continues to build upon this argument. It shows that Bangkok lies at one extreme in many transport characteristics such as the amount of travel per hectare, and within the Asian cities, it is very high in vehicle ownership and use and energy use, comparatively low in public transport use and very low in non-motorised modes. The thesis suggests that in physical planning terms, Bangkok's traffic crisis appears to stem from a set of mismatches between its transport patterns, urban form and transport infrastructure. These mismatches are between: (1) vehicle use and urban form: higher levels of private vehicle use than can be properly accommodated in its dense, tightly woven urban fabric; (2) vehicle use and road supply: levels of private vehicle use which are incompatible with its road availability and which are uncharacteristically high compared to other Asian cities; (3) transit use, urban form and road supply: lower levels of overall transit use than would be expected in a city of its urban form and road availability; (4) transit infrastructure, urban form and road supply: a public transport infrastructure which is inadequate to meet the demands for transit movement inherent in such a dense city, particularly a lack of rail infrastructure; (5) non-motorised modes and urban form: levels of non-motorised mode use which are uncharacteristically low for such a dense, mixed use urban fabric. These mismatches are mainly the consequence of a long series of inappropriate and ineffective transport policies and investments which are biased towards private transport and which have at least in part arisen from narrow and outdated transport planning processes.
In order for transport planning in Bangkok to address the suggested roots of the crisis, the thesis contends that at least two key constraints would have to be dealt with: the traditional urban transport planning process and the institutional fragmentation in transport policy and implementation. Notwithstanding, there are forces pushing in the direction of change and these are examined in terms of the growing global and local trends towards sustainability, community outrage over traffic and the role of NGOs.
Based on these findings, this thesis provides a case for a series of policies to help deal with Bangkok's traffic disaster. In line with global trends towards sustainability as an organising principle for urban policy development, these policies are offered within a framework of developing a more sustainable transport system in Bangkok. The policies suggested cover priority to public transport infrastructure development, transitoriented,mixed land use development, transport demand management, improvement of waterway transportation, facilitation of walking and cycling and institutional reform of Bangkok's transport decision making structure. Opportunities for further complementary research are suggested.
50
Pasciak, Alexander Samuel. "The theoretical development of a new high speed solution for Monte Carlo radiation transport computations." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4875.
Повний текст джерелаАнотація:
Advancements in parallel and cluster computing have made many complex
Monte Carlo simulations possible in the past several years. Unfortunately, cluster
computers are large, expensive, and still not fast enough to make the Monte Carlo
technique useful for calculations requiring a near real-time evaluation period. For Monte
Carlo simulations, a small computational unit called a Field Programmable Gate Array
(FPGA) is capable of bringing the power of a large cluster computer into any personal
computer (PC). Because an FPGA is capable of executing Monte Carlo simulations with
a high degree of parallelism, a simulation run on a large FPGA can be executed at a
much higher rate than an equivalent simulation on a modern single-processor desktop
PC. In this thesis, a simple radiation transport problem involving moderate energy
photons incident on a three-dimensional target is discussed. By comparing the
theoretical evaluation speed of this transport problem on a large FPGA to the evaluation
speed of the same transport problem using standard computing techniques, it is shown
that it is possible to accelerate Monte Carlo computations significantly using FPGAs. In
fact, we have found that our simple photon transport test case can be evaluated in excess
of 650 times faster on a large FPGA than on a 3.2 GHz Pentium-4 desktop PC running MCNP5âÂÂan acceleration factor that we predict will be largely preserved for most
Monte Carlo simulations.