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1
Pasichnyk, Inna, et Інна Олександрівна Пасічник. « Integration of the domestic transport system into European and international transport systems ». Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/50590.
Texte intégralRésumé :
1. Natsionalna Transportna Stratehiia Ukrainy Do 2030 roku [in ukr.]. – Access mode: http://publications.chamber.ua/Infrastructure/UDD/ National_Transport_Strategy_2030.pdf
2. Spivrobitnytstvo U Sferi Transportu - 2020: Predstavnytstvo Ukrainy Pry YeS [in ukr.]. – Access mode: https://ukraine-eu.mfa.gov.ua/posolstvo/galuzeve-spivrobitnictvo/transport
3. Danilieva Yu. Intehratsiia Ukrainy Do Rynku Transportnykh Posluh Krain YeS [in ukr]/ Yu. Danilieva. // Visnyk Skhidnoukrainskoho NU Im. V. Dalia. – 2017. – №3. – С. 59–63.
Supervisor – PhD in Economics, Associate Professor Klymenko V.V.Today, the problem of integration of Ukraine's transport system into the European Union has been widely discussed. It is a subject of the National Transport Strategy of Ukraine up to 2030. The transport sector of Ukraine is a significant and important segment for the country's economy, because the efficient and coordinated operation of the entire transport system is a driving force for the overall development of the country. The development of integration processes and the growth of competition in the market of transport services requires new approaches to the development of transport relations, the creation of new technologies and improving the quality of services.
Сьогодні проблема інтеграції транспортної системи України до Європейського Союзу широко обговорюється. Це предмет Національної транспортної стратегії України до 2030 року. Транспортний сектор України є важливим та важливим сегментом для економіки країни, оскільки ефективна та скоординована робота всієї транспортної системи є рушійною силою загального розвитку країни. Розвиток інтеграційних процесів та зростання конкуренції на ринку транспортних послуг вимагає нових підходів до розвитку транспортних відносин, створення нових технологій та підвищення якості послуг.
2
Rinn, Bernd. « Transport and aging in glassy systems Transport und Altern in glasartigen Systemen / ». [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9683811.
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3
Wendell, Dawn M. (Dawn Marie) 1983. « Transport in granular systems ». Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69499.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 93-98).
There are many situations in which a continuum view of granular systems does not fully capture the relevant mechanics. In order for engineers to be able to design systems for transporting granular materials, there needs to be an understanding of the mechanics of granular systems and how their non-continuous behavior affects their dynamics. This thesis takes an example of a granular system from nature and uses this system to analyze the way granular materials interact with flexible boundaries. This thesis focuses on digging in granular materials. Pinto bean plant roots were used as a model biological system, and experiments using photoelastic grains were performed to quantify the effect of the inhomogeneous forces in the substrate on the root growth. It was determined that the pinto bean roots grew between grains when the force between those grains was less than 0.5 N. This value was time-dependent and showed a previously-unquantified strengthening of the roots over time. Also, while the roots were growing in the granular substrate, they altered the forces between grains by an average of 110 mN. An analytical model of digging energy was developed to investigate the differences between diggers that are much larger than the grain size and diggers that are much smaller than the grain size. Based on this model, a design tool was created so that designers could quickly identify promising technologies for digging based on the size scale of the grains and the desired size of the digger. Finally, two elements of the plant roots, mechanical flexibility and an actuated tip, were used to create robotic diggers to quantify the associated savings in digging energy. Increasing the mechanical flexibility of the digger was shown to result in energy savings of more than 50% when decreasing the bending modulus by one order of magnitude. However, large variations in the data were observed as a result of the inhomogeneity of the granular system. These variations were quantified and were consistent with previous literature regarding forces in granular systems. Also, a numerical model was created that demonstrates that the increase in digging efficiency can be attributed to the flexibility of the digger. Experiments with diggers whose tip orientation cycled from side to side show that it is more energy-efficient to dig with this active tip only if the energy used to create the changing tip orientation is less than 2.5 x 10-⁵ J per mm dug.
by Dawn Marie Wendell.
Ph.D.
4
Novikov, Dmitry S. 1976. « Transport in nanoscale systems ». Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/39403.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2003.Includes bibliographical references.
In part I of the Thesis charge ordering and transport in arrays of coated semiconductor nanocrystals (quantum dot arrays) are studied. Charge ordering in dot arrays is considered by mapping the electrons on the dots onto the frustrated spin model on the triangular lattice. A number of phases is identified for this system. Phase diagram is studied by means of the height field order parameter. Novel correlated fluid phase is identified, in which transport of classical charges exhibits correlated behavior. Freezing transitions into commensurate ground state configurations are found to be of the first order. A novel model of transport in disordered systems is proposed to account for experimentally observed current transients in dot arrays at high bias. This transport model yields a non-stationary response in a stationary system. The model proposes a particular power law noise spectrum that is found to be consistent with experiments. In Part II of the Thesis novel effects in Carbon nanotubes are predicted. These effects can be manifest in transport measurements. First, it is shown that a strong electric field applied perpendicularly to the tube axis can fracture the Fermi surface of metallic nanotubes and significantly reduce excitation gap in semiconducting nanotubes. The depolarization problem is linked to the chiral anomaly of 1+1 dimensional Dirac fermions. Second, coupling between a surface acoustic wave and nanotube electrons is proposed as a means to realize an adiabatic charge pump. Incompressible states are identified in the single particle picture, and the corresponding minigaps are found. Conditions for pumping experiment are identified.
(cont.) Third, electron properties of a nanotube in a periodic potential are considered. It is shown that when the electron density is commensurate with the potential period, incompressible electron states exist. Electron interactions are treated in the Luttinger liquid framework, and excitation gaps corresponding to incompressible states are found using the phase soliton approach.
by Dmitry S. Novikov.
Ph.D.
5
Tang, Xian Zhu. « Transport in chaotic systems ». W&M ScholarWorks, 1996. https://scholarworks.wm.edu/etd/1539623882.
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This dissertation addresses the general problem of transport in chaotic systems. Typical fluid problem of the kind is the advection and diffusion of a passive scalar. The magnetic field evolution in a chaotic conducting media is an example of the chaotic transport of a vector field. In kinetic theory, the collisional relaxation of a distribution function in phase space is also an advection-diffusion problem, but in a higher dimensional space.;In a chaotic flow neighboring points tend to separate exponentially in time, exp({dollar}\omega t{dollar}) with {dollar}\omega{dollar} the Liapunov exponent. The characteristic parameter for the transport of a scalar in a chaotic flow is {dollar}\Omega\ \equiv\ \omega L\sp2/D{dollar} where L is the spatial scale and D is the diffusivity. For {dollar}\Omega\ \gg\ 1{dollar}, the scalar is advected with the flow for a time {dollar}t\sb{lcub}a{rcub}\ \equiv{dollar} ln(2{dollar}\Omega{dollar})/2{dollar}\omega{dollar} and then diffuses during the relatively short period 1/{dollar}\omega{dollar} centered on the time {dollar}t\sb{lcub}a{rcub}{dollar}. This rapid diffusion occurs only along the field line of the {dollar}\rm \ s\sb\infty{dollar} vector, which defines the stable direction for neighboring streamlines to converge. Diffusion is impeded at the sharp bends of an {dollar}\rm \ s{dollar} line because of a peculiarly small finite time Lyapunov exponent, hence a class of diffusion barriers is created inside a chaotic sea. This result comes from a fundamental relationship between the finite time Lyapunov exponent and the geometry of the {dollar}\rm \ s{dollar} lines, which we rigorously show in 2D and numerically validated for 3D flows.;The evolution of a general 3D magnetic field in a highly conducting chaotic media is also related to the spatial-temporal dependence of the finite time Lyapunov exponent. The Ohmic dissipation in a chaotic plasma will become a dominate process despite a small plasma resistivity. We show that the Ohmic heating in a chaotic plasma occurs in current filaments or current sheets. The particular form is determined by the time dependence of spatial gradient of the finite time Lyapunov exponent along a direction in which neighboring point neither diverge nor converge.
6
Rajbhandari, Bidur. « Modelling intelligent transport systems applications for public transport ». Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246885.
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ZERO, ENRICO. « Systems engineering approaches to safety in transport systems ». Doctoral thesis, Università degli studi di Genova, 2022. http://hdl.handle.net/11567/1064736.
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During driving, driver behavior monitoring may provide useful information to prevent road traffic accidents caused by driver distraction. It has been shown that 90% of road traffic accidents are due to human error and in 75% of these cases human error is the only cause. Car manufacturers have been interested in driver monitoring research for several years, aiming to enhance the general knowledge of driver behavior and to evaluate the functional state as it may drastically influence driving safety by distraction, fatigue, mental workload and attention. Fatigue and sleepiness at the wheel are well known risk factors for traffic accidents.
The Human Factor (HF) plays a fundamental role in modern transport systems. Drivers and transport operators control a vehicle towards its destination in according to their own sense, physical condition, experience and ability, and safety strongly relies on the HF which has to take the right decisions. On the other hand, we are experiencing a gradual shift towards increasingly autonomous vehicles where HF still constitutes an important component, but may in fact become the "weakest link of the chain", requiring strong and effective training feedback.
The studies that investigate the possibility to use biometrical or biophysical signals as data sources to evaluate the interaction between human brain activity and an electronic machine relate to the Human Machine Interface (HMI) framework. The HMI can acquire human signals to analyse the specific embedded structures and recognize the behavior of the subject during his/her interaction with the machine or with virtual interfaces as PCs or other communication systems. Based on my previous experience related to planning and monitoring of hazardous material transport, this work aims to create control models focused on driver behavior and changes of his/her physiological parameters. Three case studies have been considered using the interaction between an EEG system and external device, such as driving simulators or electronical components. A case study relates to the detection of the driver's behavior during a test driver. Another case study relates to the detection of driver's arm movements according to the data from the EEG during a driver test. The third case is the setting up of a Brain Computer Interface (BCI) model able to detect head movements in human participants by EEG signal and to control an electronic component according to the electrical brain activity due to head turning movements. Some videos showing the experimental results are available at https://www.youtube.com/channel/UCj55jjBwMTptBd2wcQMT2tg.
8
Metalidis, Georgo. « Electronic transport in mesoscopic systems ». [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985476753.
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Bonham, Jennifer D. « Women and urban transport systems / ». Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09AR/09arb714.pdf.
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Wu, Jinshan. « Quantum transport through open systems ». Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/33955.
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To study transport properties, one needs to investigate the system of interest when coupled to biased external baths. This requires solving a master equation for this open quantum system. Obtaining this solution is very challenging, especially for large systems. This limits applications of the theories of open quantum systems, especially insofar as studies of transport in large quantum systems, of interest in condensed matter, is concerned.
In this thesis, I propose three efficient methods to solve the Redfield equation --- an example of such a master equation. The first is an open-system Kubo formula, valid in the limit of weak bias. The second is a solution in terms of Green's functions, based on a BBGKY (Bogoliubov--Born--Green--Kirkwood--Yvon)-like hierarchy. In the third, the Redfield equation is mapped to a generalized Fokker-Planck equation using the coherent-state representation. All three methods, but especially the latter two, have much better efficiency than direct methods such as numerical integration of the Redfield equation via the Runge-Kutta method. For a central system with a d-dimensional Hilbert space, the direct methods have complexity of d³, while that of the latter two methods is on the order of order of polynomials of log d. The first method, besides converting the task of solving the Redfield equation to solving the much easier Schrödinger's equation, also provides an even more important conceptual lesson: the standard Kubo formula is not applicable to open systems.
Besides these general methodologies, I also investigate transport properties of spin systems using the framework of the Redfield equation and with direct methods. Normal energy and spin transport is found for integrable but interacting systems. This conflicts with the well-known conjecture linking anomalous conductivity to integrability, and it also contradicts the relationship, suggested by some, between gapped systems (Jz > Jxy) and normal spin conductivity. I propose a new conjecture, linking anomalous transport to the existence of a mapping of the problem to one for non-interacting particles.
11
Souza, Aldilene Saraiva. « Electronic Transport in Molecular Systems ». reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/12671.
Texte intégralRésumé :
SOUZA, Aldilene Saraiva. Electronic Transport in Molecular Systems. 2012. 107 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2012.Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-06-08T19:17:13Z No. of bitstreams: 1 2012_tese_assouza.pdf: 11520100 bytes, checksum: 04bcbbf301130ab097bf5c01340034df (MD5)
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Nesta tese apresentamos o estudo teórico de transporte eletrônico de dispositivos moleculares em dois problemas distintos. No primeiro, comparamos medidas via microscopia de tunelamento (STM) com cálculos de primeiros princípios onde a tensão aplicada em uma mono camada de moléculas auto-montadas, denominadas: 5-(4-piridina)-1,3,4-oxadiazol-2-tiol (HPYT) e 5-(4-fenil)-1,3,4-oxadiazol-2-tiol (HPOT) mostram a distribuição local de carga. Essas moléculas são depositadas sobre um substrato de ouro tipo (1 1 1). A formação destas camadas moleculares foi confirmada por medidas de STM. Cálculos baseados na teoria do funcional da densidade (DFT) foram realizados para obter a conformação mais estável da interação molécula/substrato. Verificamos uma grande semelhança entre os resultados teóricos e as medidas de imagem de STM. A partir desta comparação, sugerimos que o átomo de enxofre na molécula HPYT e HPOT está ligado à superfície de ouro por uma ligação direta à um único átomo de ouro. Para descrever a corrente de tunelamento ao longo da mono camada molecular sobre a superfície de Au (1 1 1) foi proposto um modelo quântico baseado na técnica de equação mestra. Nós investigamos também, propriedades de transporte de spin em uma cadeia de poliacetileno (como ponte) acoplada à uma nano fita de carbono tipo zigue-zague (ZGNRs) funcionando como eletrodos. Os cálculos de transporte foram efetuados usando técnica de funções de Green fora do equilíbrio (NEGF), combinada com a teoria do funcional da densidade (DFT). Trabalhos anteriores demonstraram que as ZGNRs exibem um ordenamento antiferromagnético (AF) e meia-metalicidade nos estados provenientes da borda, que podem ser destruídos com aplicação de um forte campo elétrico externo. Neste trabalho, nós demonstramos que a ligação entre a ponte molecular e átomos não-equivalentes de carbono (A/B) na sub rede de grafeno ZGNRs pode ocorrer de duas formas produzindo um sistema metálico ou semicondutor fortemente dependente do acoplamento local. Ao considerar o anel de carbono onde a cadeia está ligada, uma ligação se assemelha a uma ligação para no benzeno, enquanto a outra ligação é semelhante a uma ligação meta. Estas geometrias geram transmissão eletrônica distinta, que pode ser controlada sob um campo elétrico transversal.
12
Sood, R. « Transport phenomena in polymeric systems ». Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1985. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3259.
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李嘉皓 et Ka-ho Carol Lee. « Public transport transfer systems : the policies and management of urban transport systems in Hong Kong ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B4293008X.
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Lee, Ka-ho Carol. « Public transport transfer systems the policies and management of urban transport systems in Hong Kong / ». Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B4293008X.
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Luk, Yiu-wah Everett, et 陸耀華. « Potential applications of intelligent transport systems in urban freight transport ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B29851397.
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Mbiydzenyuy, Gideon. « Quantitative Assessment of Intelligent Transport Systems for Road Freight Transport ». Doctoral thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00553.
Texte intégralRésumé :
In this thesis, methods for using computer-based models as support tools for assessing Transport Telematic Services (TTSs) are studied. Such assessments provide one way to understand how TTSs can address problems caused by transportation, such as accidents, emissions, and energy consumption. TTSs are services based on telematic systems which are Intelligent Transport Systems (ITS) involving the integrated use of information and communication technologies in transport. The focus is on TTSs that are relevant for road freight transport, even though the suggested methods can easily be adapted for TTSs in other areas. We characterize TTSs, e.g., in terms of their functionalities, and apply computer-based modeling for pre-deployment assessment of various TTSs (from an ex-ante perspective). By analyzing information provided by the suggested computer-based models, it is possible to make an informed decision whether to (or not to) deploy a given TTS. A review of previous studies reveals information about relevant TTSs for freight transport in areas such as driver support, administration, safety, traffic management, parking, and goods handling. A hierarchical clustering algorithm and a k-minimum spanning tree algorithm were employed to analyze synergies of TTSs. Synergies can enable identification of sets of TTSs that can lead to cost savings if deployed on a common platform (cf. Multi-Service Architectures). An analytical model inspired by the net present value concept is used to estimate quantified societal benefits of TTSs. An optimization model is formulated and solved using a branch and bound method to determine an optimal combination of TTSs taking into consideration societal benefits, costs, dependencies, and synergies. The optimization model also addresses possible system architectures for achieving multiple TTSs. Dominance rough set approach is used to assess and compare benefit areas for TTSs specific to truck parking. The benefit areas are suggested with the help of conceptual modeling, which describes functional models of a system in terms of states, transitions among states, and actions performed in states. The main scientific contributions of the thesis are in suggesting new quantitative models, extending and applying existing models in the assessments of TTSs, and obtaining results that can help decision-makers select TTSs for medium-to long-term investments. Researchers can employ and build on the proposed methods when addressing different scenarios (geographic or organizational) involving similar TTSs. By studying a range of TTSs and possible Multi-Service Architecture concepts for such TTSs, the thesis contributes to achieving convergence of TTSs in a Multi-Service Architecture environment that will improve cost efficiency, minimize redundancies, and encourage the establishment of standards in the deployment of TTSs in road freight transport. TTSs implemented in such an environment can contribute to optimizing available capacity, accuracy, speed, and efficiency of road freight transport systems.
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Davaasambuu, Jav, Friedrich Güthoff, Klaudia Hradil et Götz Eckold. « Phonons in demixing systems ». Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-188279.
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Chaudhuri, Pinaki, Ludovic Berthier, Srikanth Sastry et Walter Kob. « Diffusion in glassy systems ». Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-190297.
Texte intégralRésumé :
The transport properties of glass-forming systems have many features that are not found in normal liquids. Among them is a very strong sensitivity of the relaxation times upon a change in temperature and the presence of so-called dynamical heterogeneities.
In this review we discuss these unusual properties and present the results of a simple lattice gas model that helps to understand the origin of these heterogeneities from the microscopic level. Furthermore we discuss a simple analytical model, the continuous time random walk, and show that it allows to describe some aspects of the relaxation dynamics of glass-forming systems on a semi-quantitative level.
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Occhino, Deborah Ann. « Vibrio cholerae iron transport : characterization of two tonB systems and components of a heme transport system / ». Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Russell, Matthew. « Transport processes in spatially disordered systems ». Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/transport-processes-in-spatially-disordered-systems(c4d3e5f6-681e-4403-bb47-65de4a9b2c5a).html.
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Transport phenomena in nature occur in spatially complex and heterogeneous systems, such as the lung and the placenta. Motivated by such examples, we seek to characterise the effects of and interaction between multiscale spatial structure and disorder in models of transport and flow. We first investigate an individual-based transport model which incorporates two sources of noise and transport processes occurring over disparate lengthscales. Particles can hop stochastically between sites on a lattice in one spatial dimension and are taken up via first-order kinetics at discrete sinks with random strengths, sparsely but periodically located along the domain. Simulations indicate that disordered sink strengths induce long-range correlations in the particle concentration which are absent when sinks are of fixed strength. Furthermore, mean concentrations are elevated by disorder. Exploiting the separation of lengthscales and properties of the stochastic hopping, we use a continuum limit to derive approximate, homogenized expressions describing the correlations and elevated mean. These involve non-local combinations of the leading-order concentration profile and the Green's function associated with the corrections. We show that the correction to the mean concentration is always non-negative and so the leading-order classical homogenization approximation underestimates the mean. We finally classify the regions of parameter space according to the dominant physical processes in each region and put bounds on the validity of the homogenization approach by analysing the sizes of fluctuations due to disorder. We next study a related model of solute transport in one dimension where sinks of equal strength are distributed randomly along a line. Extending the Green's function approach, we investigate the interactions between the discrete nature of the sinks and their disordered locations. We find that classical two-scale expansion-based homogenization fails to accurately predict higher-order corrections and develop refined predictions. These methods extend to handling spatially disordered sinks, and we demonstrate that our predictions of the spatial correlations and corrections to leading-order means agree well with simulations in large areas of parameter space and for both weak and strong disorder. The strength of the spatial disorder can affect whether the discrete-to-continuous or disorder effects are the most important. Finally, we study the flow through a two-dimensional disordered porous medium. We perform direct numerical simulations of a low Reynolds number flow past a series of obstacles. Applying spatial perturbations to individual obstacles in an otherwise periodic arrangement, and comparing with a completely periodic array, we investigate the long-range effects in the velocity and pressure fields. This is effective a numerical approximation of a series of Green's functions, inspired by the theoretical framework used in our previous models. We then generate large ensembles of weakly and strongly disordered porous media and compare the statistics of the flow rate with predictions made by Darcy's law, typically applicable to large, periodic arrays. Depending on the type of spatial disorder, mean flow rates can be either elevated or diminished compared with a periodic array and Darcy's law. Furthermore, we analyse the decay in the fluctuations around the mean flow rate as the size of the array is increased.
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Cheung, Suk-ling. « The potential of intelligent transport system (ITS) development in road transport of Hong Kong ». Click to view the E-thesis via HKUTO, 2001. http://sunzi.lib.hku.hk/hkuto/record/B42575680.
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Lui, Chi-keung Arthur. « Transport properties of hybrid mesoscopic systems ». Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B30727339.
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McGlade, Desmond P. « Information systems strategy in air transport ». Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA273125.
Texte intégralRésumé :
Thesis (M.S. in Information Technology) Naval Postgraduate School, September 1993.Thesis advisor(s): Haga, William James ; Sessions, Sterling. "September 1993." Bibliography: p. 121-126. Also available online.
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Burmeister, Björn. « Transport processes in quantum spin systems ». [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=958235295.
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Yang, Ping 1961. « Thermal transport in mesoscopic dielectric systems ». Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85107.
Texte intégralRésumé :
Although the study of thermal transport in condensed matter has a very long history, it continues to be an active field of work due to its importance in many applications. The research subject reported in this thesis is on theoretical investigations of thermal energy transport in systems whose linear dimension is less than the wavelength of thermal phonons. Such situations occur in mesoscopic and nanoscopic scale dielectric structures which can now be fabricated in a number of laboratories. Due to the small system dimensions, phonons must be treated as waves. Thermal energy transport, therefore, must be treated as phonon wave propagation through the system.After reviewing the general physics of thermal energy transport in the classical regime, we derive, for dielectric materials, a formula for thermal energy flux in devices involving multi-terminals each connected to a thermal reservoir at local equilibrium. The energy flux is driven by a temperature bias and traverses the system by virtue of phonon wave scattering. A multi-terminal thermal conductance formula is derived in terms of phonon transmission coefficient. Using our theoretical formulation, we investigate thermal transport properties of both two-terminal and four-terminal dielectric devices by solving the quantum scattering problem using a mode matching numerical technique.
For thermal transport in a T-shaped dielectric nanostructure with two-terminals at low temperature, due to quantum interference the transmission coefficient of phonons becomes quite complicated. We found that the value of phonon transmission coefficients at zero energy may be unity or zero depending on a geometrical ratio of the nanostructure. The transmission has an oscillation behavior with quasi-periodicity and irregularity. The thermal conductance is found to increase monotonically with temperature---a result that we conclude to be generally true for any two-terminal device. We confirm the existence of the universal quantum of thermal conductance which exists at the low temperature limit, and such a quantum is robust against all the system parameters.
The physical behavior of four-terminal thermal conductance for mesoscopic dielectric systems with arbitrary shapes of scattering region is also investigated in detail. If we make a two-terminal measurement in the four-terminal device, the two-terminal conductance is a monotonically increasing function of temperature, and is equal to the universal quantum of thermal conductance masked by a geometric factor. If we make a four-terminal measurement, the four-terminal conductance has a non-monotonic dependence. In the low temperature limit, we predict that the four-terminal conductance diverges inversely proportional to temperature.
Finally, we discuss an interesting theoretical problem on the general behavior of thermal conductance for multi-terminal systems when thermal carriers satisfy fractional exclusion statistics. Our analysis allows us to conclude that results for fractional exclusion statistics are quite different from those of the Bose-Einstein statistics.
26
Tyreman, David R. « Peptide transport systems and antibiotic design ». Thesis, Bangor University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277600.
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Lui, Chi-keung Arthur, et 呂智強. « Transport properties of hybrid mesoscopic systems ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30727339.
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Cao, Jingnan, et 曹靖楠. « Thermoelectric transport properties in nanoscale systems ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49799708.
Texte intégralRésumé :
As the fast development of nanotechnology and further industrial applications, theoretical investigations upon nanoscale devices are in urgent need. Until now several formalisms have been well established in quantum transport of mesoscopic areas, including of tight-binding and first principle calculations. In this dissertation those methods were partly explored to explore transport and thermoelectric features in various models and actual devices.
The density functional theory plus non-equilibrium Green’s function serves well in the probing process of transport properties like conductance in mesoscopic systems. Atoms’ positions were treated as the only input parameters and one computation package based on NEGF-DFT loop was utilized to get the numerical results, then the corresponding thermal quantities were analysed.
The coherent transport exhibits an obvious character in transmission spectrum called transmission node, whose existence relies on the asymmetric structure of molecular junctions. In the main body of the thesis, firstly two types of model simulation were tested, and the following thermoelectric quantities showed that there’s one interesting signature in the thermopower performance, which was its temperature independence around transmission node. Through comparisons between different system parameters a rough regular pattern was obtained, that the degree of zero transmission and the energy difference around it influenced this temperature invariance feature at the same time. While these two properties were mainly determined by the natural structure of devices.
Besides model simulations the ab initio investigations were also carried out. Although the actual device was not easily altered as ideal models, some similar behaviours in the transmission and thermal curves were still found out. The temperature insensitivity was considered to appear more often in a π electron dominated molecular structure rather than ones with σ electron interactions.published_or_final_version
Physics
Master
Master of Philosophy
29
Coghlan, Brian P. « Solids transport in combined sewerage systems ». Thesis, University of Abertay Dundee, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308961.
Texte intégral
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Moore, Christopher Paul. « Tunneling Transport Phenomena in Topological Systems ». Thesis, Clemson University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13420479.
Texte intégralRésumé :
Originally proposed in high energy physics as particles, which are their own anti-particles, Majorana fermions have never been observed in experiments. However, possible signatures of their condensed matter analog, zero energy, charge neutral, quasiparticle excitations, known as Majorana zero modes (MZMs), are beginning to emerge in experimental data. The primary method of engineering topological superconductors capable of supporting MZMs is through proximity-coupled semiconductor nanowires with strong Rashba spin-orbit coupling and an applied magnetic field. Recent tunneling transport experiments involving these materials, known as semiconductor-superconductor heterostructures, were capable for the first time of measuring quantized zero bias conductance plateaus, which are robust over a range of control parameters, long believed to be the smoking gun signature of the existence of MZMs. The possibility of observing Majorana zero modes has garnered great excitement within the field due to the fact that MZMs are predicted to obey non-Abelian quantum statistics and therefore are the leading candidates for the creation of qubits, the building blocks of a topological quantum computer. In this work, we first give a brief introduction to Majorana zero modes and topological quantum computing (TQC). We emphasize the importance that having a true topologically protected state, which is not dependent on local degrees of freedom, has with regard to non-Abelian braiding calculations. We then introduce the concept of partially separated Andreev bound states (ps-ABSs) as zero energy states whose constituent Majorana bound states (MBSs) are spatially separated on the order of the Majorana decay length. Next, through numerical calculation, we show that the robust 2 e2/h zero bias conductance plateaus recently measured and claimed by many in the community to be evidence of having observed MZMs for the first time, can be identically created due to the existence of ps-ABSs. We use these results to claim that all localized tunneling experiments, which have been until now the main way researchers have tried to measure MZMs, have ceased to be useful. Finally, we outline a two-terminal tunneling experiment, which we believe to be relatively straight forward to implement and fully capable of distinguishing between ps-ABSs and true topologically protected MZMs.
31
Yan, C. « Electron transport in integrated quantum systems ». Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1531982/.
Texte intégralRésumé :
In this thesis, integrated quantum devices defined using a split gate technique are studied experimentally. These integrated devices provide a novel platform to investigate the property of quantum systems, such as spin polarization, via non-local measurement. Information extracted from these integrated devices leads to a comprehensive understanding of the puzzling phenomenon such as the 0.7 anomaly. Meanwhile, these devices are possibly suitable for studying quantum entanglement because perturbation due to measurement is minimized in the non-local setup. Devices demonstrated here are also promising to be used as a building block such as quantum injector/detector or quantum bus (which is a information channel where quantum information can be transported coherently) for more complicated quantum systems. In the first experiment, a transverse electron focusing in n-type GaAs heterojunction is present where pronounced splitting of odd focusing peaks are observed. From the asymmetry of sub-peaks of the first focusing spin polarization is extracted directly, this provides direct evidence for intrinsic spin polarization in a quasi-one-dimensional system. Parameters which may affect transverse electron focusing are studied systemically. Changing the shape of the injector, thus tuning the adiabaticity of the injection process, can influence the presence of peak splitting or not, with the sharp (non-adiabatic) injector the peak splitting is absent while peak splitting is observed with the flat (adiabatic) injector. Adjusting the length of injector affects the spin polarization, the longer the channel the higher the spin polarization can be achieved. This highlights the role of exchange interaction which results in the spin polarization in the quasi-1D channel. Applying a dc source-drain bias leads to such a result, peak splitting is preserved with negative bias while it smears out with positive bias when the bias is above a particular value (0.5 mV in the experiment), this proves the existence of spin-gap. In the second experiment, the coupling between different quantum devices are investigated by using an integrated quantum device consisting of an QPC and electronic cavity, where the cavity is defined with the arc-shaped gate and an inclined reflector. Unique features such as the double-peak structure occurs in the 1D-2D transition regime of the arc-QPC and 5 fine oscillations associated with conductance plateaus and 0.7 anomaly are observed when the reflector voltage is sufficiently negative and these features smear out when the reflector voltage is less negative. The double-peak structure and fine oscillations are proved to arise from the coupling between the discrete states in the QPC and continuum cavity state by the manifestation of Fano resonance via tuning reflector voltage or small transverse magnetic field. In the third experiment, quantum interference in a double-cavity system is studied by magneoresistance measurement. An unique evolution of the line shape of the magnetoresistance are observed, the magnetoresistance has a Lorentzian shape, corresponding to ergodic and chaotic motion, when the injector conductance is sufficiently small and then alters into linear line shape arising from non-ergodic and regular motion when injector is opens a bit more and finally a Lorentzian shape when the injector opens even further. Apart from the line shape, the strength of the magnetoresistance is found to fluctuate with injector conductance, it is enhanced at conductance plateaus and weakens elsewhere. Such behaviours are likely to arise from both deformation of the arc-shaped potential barrier at the vicinity of injector and detector QPC as well as the non-uniform spatial distribution of the cavity state.
32
Greenbaum, Daniel. « Quantum spin transport in paramagnetic systems ». Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32417.
Texte intégralRésumé :
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2005.Includes bibliographical references (p. 87-90).
We have studied the transport of magnetization and energy in systems of spins 1/2 on a lattice at high temperature. This work was motivated by recent experiments which observed "spin diffusion" among the dipolar coupled nuclear spins of the insulator calcium fluoride, under conditions where it was appropriate to neglect the coupling to any heat reservoir. The dynamics under these conditions is coherent and reversible, yet signatures of irreversibility (i.e. diffusion) are typically observed. This state of affairs poses a formidable conceptual puzzle. In this thesis we present both phenomenological and microscopic models of spin diffusion, retaining the important aspects of statistical approaches to transport while incorporating relevant quantum effects. These methods allow an efficient calculation of energy diffusion for a long- range interaction, which has largely been an intractable problem. We study transport in two different limits, that where the XY term of the spin Hamiltonian is dominant, and that where it can be treated as a perturbation compared to the Ising term. In the case of dipolar couping, both limits are found to show slightly more rapid diffusion of inter spin energy than magnetization, in qualitative agreement with experiments.
by Daniel Greenbaum.
Ph.D.
33
Shen, Chen. « Spin transport in ferromagnet-semiconductor systems ». Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610302.
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Pollock, Felix Alexander. « Energy transport in open quantum systems ». Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:41f104b5-718d-4f1c-a224-fe47c324dbbe.
Texte intégralRésumé :
This thesis is concerned with modelling the dynamics of open quantum systems in several different contexts. Of principal interest is the manner in which the environment can modify, or even dominate, a system’s quantum behaviour in order to facilitate the transport of energetic excitations. In the first research chapter, a time-local, non-Markovian quantum master equation is derived in a variationally defined reference frame, for networks of two-level systems coupled to bosonic environments. The predictions of this master equation are then compared with those derived using both weak-coupling and polaron approximations. The variational master equation is found to agree with these standard approaches in their regimes of validity, whilst interpolating between them in intermediate parameter regimes. The second research chapter focusses on the dynamics of a superconducting double quantum dot embedded in a resonant circuit. The device is considered in a regime where the ground state consists of a coherent spatial superposition of a single Cooper pair, which can be excited by a variety of interactions with the environment. The relevant transition rates are calculated and the processes responsible are identified. A numerical simulation of the system is then used to explain experimental data, and show that for certain parameters a significant fraction of excitations occur via absorption of photons from the environment. The final chapter considers a model for an olfactory receptor, in which odorant molecules are recognised by their vibrational modes. Electron transfer occurs in the receptor, dependent on the presence of a vibrational mode of the right frequency. A quantum master equation for the system is derived, and the resulting dynamics is compared to earlier semi-classical treatments. The behaviour of the receptor is found to be sensitive not only to the frequency of the vibrational mode, but also to the character of the surrounding environment. Increased dissipation on the odorant mode, as well as the presence of higher frequencies in the environment is found to improve the frequency resolution of the receptor.
35
Макеєв, Андрій Олександрович, et Andrii Oleksandrovich Makeiev. « Implementation of UAV systems on transport ». Thesis, National Aviation University, 2021. https://er.nau.edu.ua/handle/NAU/51080.
Texte intégralRésumé :
1. Повітряний кодекс України від 19.05.2011 № 3393-VI Режим доступу: https://zakon.rada.gov.ua/laws/show/3393-17/conv#n9
2. Pan-European drone safety rules have been approved by the European Parliament. News 12-06-2018. Official site of the European Parliament.URL: http://www.europarl.europa.eu/news/en/press-room/20180607IPR05239/eu-wide-rules-forsafety-of-drones-approved-by-european-parliament.
3. Юхименко К.І. Писаренко Н.Л. Врахування соціального аспекту в процесі оцінки конкуркнтноспроможності товару на ринку товарів та послуг для надзвичайних ситуаційна прикладі компанії-виробника дронів. Актуальні проблеми економіки і управління: Зб. наук. праць. К.: КПІ ім. Ігоря Сікорського. 2020. Вип. 14. Режим доступу: http://ape.fmm.kpi.ua/article/view/205371The modern world is rapidly evolving and improving, while modern transport technologies are developing. Every year we can see new methods and approaches to improve passenger and luggage transportation, including by air. One of the newest methods is the introduction of unmanned aerial vehicles - aircraft designed to fly without the physical presence of the pilot on board. According to the Air Code, an unmanned aircraft is an aircraft designed to fly without a pilot on board, the flight control of which is controlled by a special control station located outside the aircraft. It is known that drones were originally designed for the military goals, but in a relatively short time began to be used in various spheres of public life and sectors of the economy. At the same time, with the rapid development of the drone market, it has become clear that they pose a number of security risks. Even drones weighing less than 150 kg can damage an airplane, injure and pollute the air and sound.
Сучасний світ швидко розвивається та вдосконалюється, тоді як сучасні транспортні технології розвиваються. Щороку ми можемо побачити нові методи та підходи для вдосконалення перевезень пасажирів та багажу, в тому числі повітряним транспортом. Одним із найновіших методів є впровадження безпілотних літальних апаратів - літаків, призначених для польоту без фізичної присутності пілота на борту. Згідно з Повітряним Кодексом, безпілотний літак - це літак, призначений для польоту без пілота на борту, управління польотом якого контролюється спеціальною станцією управління, розташованою за межами літака. Відомо, що спочатку безпілотники були розроблені для військових цілей, але за відносно короткий час стали застосовуватися в різних сферах суспільного життя та галузях економіки. У той же час, з бурхливим розвитком ринку безпілотників, стало ясно, що вони створюють низку ризиків для безпеки. Навіть безпілотники вагою менше 150 кг можуть пошкодити літак, травмувати та забруднювати повітря та звук.
36
Berthe, Maxime. « Electronic transport in quantum confined systems ». Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-Berthe.pdf.
Texte intégralRésumé :
Depuis l'avènement des nanotechnologies, une grande quantité de matériaux sont façonnés à l'échelle du nanomètre par des techniques diverses et l'intégration de ces nanostructures demande une caractérisation de leur structure électronique. La microscopie à effet tunnel est adaptée à ces études car elle permet l'adressage de nanostructures uniques pour mesurer leur structure électronique. Nous rapportons ici l'étude du transport électronique dans deux types de nanostructures: des nanotubes de carbone simple paroi déposés sur une surface d'or et des atomes uniques de silicium sur un substrat de silicium. Dans la première étude, le couplage faible entre un nanotube et le substrat permet d'accéder à la densité d'états unidimensionnelle des nanotubes et autorise la formation de défauts ponctuels, ayant des états localisés dans la bande interdite des nanotubes. Cette modification, réversible, de la structure atomique des nanotubes de carbone amène des opportunités concernant la modification controlée et à volonté de leurs propriétés électroniques. La deuxième étude vise à caractériser la dynamique des porteurs dans une liaison pendante de silicium énergétiquement isolée de tout autre état électronique sur une surface Si(111). L'analyse du transport révèle un courant inélastique mettant en oeuvre la recombinaison non radiative des électrons de la pointe avec des trous capturés par l'état de la liaison pendante, grâce à l'émission de vibrations. La spectroscopie à effet tunnel montre de plus que l'on peut caractériser l'efficacité de capture d'un état quantique unique, en connaissant son niveau d'énergie, sa fonction d'onde, sa section de capture et le couplage électron-phonon.
37
Ferone, Raffaello. « Thermoelectric transport in disordered mesoscopic systems ». Université Joseph Fourier (Grenoble), 2006. http://www.theses.fr/2006GRE10036.
Texte intégralRésumé :
Landau theory of Fermi liquids foresees that the charge and heat are tranported by the same objects: the fermionic Landau quasi-particles. In a very general way, it is true if the screening among particles is quite strong to can consider the system as composed yet by independent particles. This is the case for the electron sea in an ordinary bulk metal. The existance of just one responsible for charge and heat transport is expressed by the Wiedemann-Franz (WF) law. It states that the ratio between the thermal and electrical conductivity depends on temperature by a constant which is more or less the same for several metals. The constant of proportionality is called the Lorenz number. What happens if the above-mentioned condition on screening is no longer satisfied, as for example in low-dimensional systems or electronic low-density systems ? The thesis is diveded into two parts. In the first one, we studied the thermal and electrical transport in a disordered quantum wire; in the second one, the influence of superconducting fluctuations on thermal conductivity in granular metalsLa théorie de Landau des liquides de Fermi prévoit que la charge et la chaleur sont transportées par les mêmes objets: les quasi-particules fermionics de Landau. De façon très général, ceci est vrai, si l'écrantage parmi les particules dans le système est assez fort pour pouvoir continuer à considérer le système comme composé de particules indépendantes. C'est le cas, par exemple, pour la mer d'électrons dans un métal ordinaire. L'existence d'un même responsable pour le transport de la charge et de la chaleur est exprimé par la lois de Wiedemann-Franz (WF) qui affirme que le rapport entre la conductivité thermique et électrique dépend de la température par une constante qui est plus au moins la même pour plusieurs métaux. La constante de proportionnalité est appelé nombre de Lorenz. Que se passe-t-il si les conditions concernant l'écrantage que nous avons mentionnées ne sont plus satisfaites, comme par exemple dans les systèmes à dimensionalité réduite, ou des système à basse densité électronique ? Le travail de thèse est divisé en deux parties. Dans la première partie, nous avons étudié le transport thermique et électrique dans un fil quantique désordonné; dans la deuxième, l'influence des fluctuations supraconductives sur la conductivité thermique dans un métal granulaire
38
Rinn, Bernd. « Transport and aging in glassy systems ». [S.l. : s.n.], 2001. http://nbn-resolving.de/urn:nbn:de:bsz:352-opus-7479.
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Romero, Gomez Pedro. « Transport Phenomena in Drinking Water Systems ». Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194495.
Texte intégralRésumé :
The current computer models used for simulating water quality in potable water distribution systems assume perfect mixing at pipe junctions and non-dispersive solute transport in pipe flows. To improve the prediction accuracy, the present study examines and expands these modeling assumptions using transport phenomena analyses. Whereas the level of solute mixing at a cross-type junction is evaluated numerically via Computational Fluid Dynamics (CFD), the axial transport in laminar flows is investigated with both CFD simulations and corresponding experimental runs in a single pipe. The findings show that solute mixing at junctions is rather incomplete owing to the limited spatio-temporal interaction that occurs between incoming flows with different qualities. Incomplete mixing shifts the expected propagation patterns of a chemical or microbial constituent from widely-spread to narrowly-concentrated over the service area. On the other hand, solute dispersion is found to prevail over advective transport in laminar pipe flows. Thus, this work develops axial dispersion rates through parameter optimization techniques. By accounting for axial dispersive effects, the patterns of solute delivery shifted from high concentrations over short time periods to lower doses at prolonged exposure times. In addition, the present study integrates the incomplete mixing model into the optimal placement of water quality monitoring stations aimed at detecting contaminant intrusions.
40
Wilkinson, Aidan. « Transport phenomena in two-phase systems ». Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25574.
Texte intégralRésumé :
The physics of two-phase systems is explored here, particularly magneto-transport and low temperature d.c. conductivity in thin films. The extraordinary magnetoresistance (EMR) effect was analysed in the context of previous experimental and theoretical considerations. The magnetoresistance (MR) may be enhanced by up to two orders of magnitude by changing the geometry. This was investigated using finite element analysis. Thin film samples consisting of a layered structure of Germanium-Tin-Germanium (Ge-Sn-Ge) were created in collaboration with Shandong University in China. Ge layers were kept at a constant thickness across all samples, with variable Sn thickness. Regions of Sn form island-like shapes ten times larger than the average film thickness, as is seen in scanning electron microscope (SEM) images. Raman spectroscopy was conducted on these samples, from which it is concluded that the Ge layers are amorphous in nature. It was seen that there is a relationship between the electrical resistance and the film thickness which is indicative of a metal-insulator transition (MIT). The temperature dependence of resistivity was subsequently investigated. The temperature coefficient of resistivity (TCR) of the samples is seen to become negative as the thickness of the Sn layer is reduced below a certain critical thickness. Depending on their thickness, samples were designated as metallic or insulator, and various models associated with metals and insulators fitted to the data. While it is impossible to be absolutely certain of the validity of each of the models, some are a better fit than others. The same temperature dependence of resistivity was measured with an applied magnetic field. This is compared with the previous EMR investigation, however the MR of the samples is only of the order of a few percent which corresponds to ordinary MR, seen in most metals. The magnetic field measurements suppress a resistivity down-turn at very low temperatures (T < 10K) which suggests the presence of superconductivity. Analysis of dr=dT shows that the onset of superconductivity is lower for samples with a lower Sn thickness. Additionally, the deposition rate of the Sn layer affects the resistivity significantly; a higher deposition rate causes a decrease in resistivity. It is supposed that this is due to a change in the microstructure of the film. Finally, piezo-resistivity was considered by applying mechanical compression to the samples. The added pressure causes a drop in resistivity.
41
Hadjidimitriou, Natalia <1979>. « Classification algorithms for Intelligent Transport Systems ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7107/5/Natalia_Selini_Hadjidimitriou_Tesi.pdf.
Texte intégralRésumé :
Intelligent Transport Systems (ITS) consists in the application of ICT to transport to offer new and improved services to the mobility of people and freights. While
using ITS, travellers produce large quantities of data that can be collected and analysed to study their behaviour and to provide information to decision makers and
planners. The thesis proposes innovative deployments of classification algorithms for Intelligent Transport System with the aim to support the decisions on traffic
rerouting, bus transport demand and behaviour of two wheelers vehicles. The first part of this work provides an overview and a classification of a selection
of clustering algorithms that can be implemented for the analysis of ITS data.
The first contribution of this thesis is an innovative use of the agglomerative hierarchical clustering algorithm to classify similar travels in terms of their origin and destination, together with the proposal for a methodology to analyse drivers’ route choice behaviour using GPS coordinates and optimal alternatives. The clusters
of repetitive travels made by a sample of drivers are then analysed to compare observed route choices to the modelled alternatives. The results of the analysis show that drivers select routes that are more reliable but that are more expensive in terms of travel time. Successively, different types of users of a service that provides information on the real time arrivals of bus at stop are classified using Support Vector Machines. The results shows that the results of the classification of different types of bus transport users can be used to update or complement the census on
bus transport flows. Finally, the problem of the classification of accidents made by two wheelers vehicles is presented together with possible future application of
clustering methodologies aimed at identifying and classifying the different types of accidents.
42
Hadjidimitriou, Natalia <1979>. « Classification algorithms for Intelligent Transport Systems ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7107/.
Texte intégralRésumé :
Intelligent Transport Systems (ITS) consists in the application of ICT to transport to offer new and improved services to the mobility of people and freights. While
using ITS, travellers produce large quantities of data that can be collected and analysed to study their behaviour and to provide information to decision makers and
planners. The thesis proposes innovative deployments of classification algorithms for Intelligent Transport System with the aim to support the decisions on traffic
rerouting, bus transport demand and behaviour of two wheelers vehicles. The first part of this work provides an overview and a classification of a selection
of clustering algorithms that can be implemented for the analysis of ITS data.
The first contribution of this thesis is an innovative use of the agglomerative hierarchical clustering algorithm to classify similar travels in terms of their origin and destination, together with the proposal for a methodology to analyse drivers’ route choice behaviour using GPS coordinates and optimal alternatives. The clusters
of repetitive travels made by a sample of drivers are then analysed to compare observed route choices to the modelled alternatives. The results of the analysis show that drivers select routes that are more reliable but that are more expensive in terms of travel time. Successively, different types of users of a service that provides information on the real time arrivals of bus at stop are classified using Support Vector Machines. The results shows that the results of the classification of different types of bus transport users can be used to update or complement the census on
bus transport flows. Finally, the problem of the classification of accidents made by two wheelers vehicles is presented together with possible future application of
clustering methodologies aimed at identifying and classifying the different types of accidents.
43
Naumov, Sergej, Rustem Valiullin, Jörg Kärger et Bernd Smarsly. « Diffusion in hierarchical pore systems ». Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-191078.
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Watson, Edward Bruce. « Diffusion in Solid-Earth Systems ». Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-184708.
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Schneider, Judith. « Dynamical structures and manifold detection in 2D and 3D chaotic flows ». Phd thesis, [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973637420.
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Andolfato, Daniele Marques. « Racionalização do transporte público por ônibus da cidade de Jaú ». Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-29052007-161607/.
Texte intégralRésumé :
Este trabalho enfoca o transporte público coletivo da cidade de Jaú. Os objetivos precípuos da dissertação são: fazer um diagnóstico do sistema de transporte por ônibus, no tocante à qualidade e à eficiência; e apresentar um projeto de racionalização do sistema (melhoria da qualidade e da eficiência). Os problemas mais graves verificados no diagnóstico foram os seguintes: existência de áreas ocupadas com acessibilidade insatisfatória (situadas além da distância aceitável da rede de linhas), superposições de áreas de influência das linhas, grande intervalo entre atendimentos devido ao excesso de linhas, ausência de integração tarifária, integração física precária, lotações baixas nos períodos fora dos picos, acúmulo de ônibus nos pontos de parada devido à coincidência de horários de diversas linhas, atrasos excessivos na área central, falta de abrigos na maioria dos pontos de parada, etc. No plano de racionalização desenvolvido foram previstas as seguintes principais ações: reestruturação da rede de linhas com a diminuição da quantidade de rotas e eliminação das superposições e faltas de cobertura espacial adequada, redução do intervalo entre atendimentos nas linhas, implantação de estação central fechada para promover integração física e tarifária, pavimentação/recapeamento de alguns trechos de vias, melhoria da sinalização viária nas ruas utilizadas pelos ônibus, melhoria do sistema de informação ao usuário, implementação de programação operacional racional, etc. Em termos de eficiência, os principais benefícios do sistema proposto são: redução da frota de 21%, redução da quilometragem percorrida de 18% e redução do custo de operação de 20%. No tocante à qualidade, os principais ganhos são: melhoria da acessibilidade (cobertura espacial), redução do intervalo entre atendimentos, redução dos tempos de viagem, promoção de integração tarifária, promoção de integração física adequada, aumento do número de abrigos nas paradas, melhoria da superfície de rolamento das vias utilizadas pelos coletivos, etc.This work focuses the urban collective public transportation system by bus of the city of Jaú. The main objectives of this work is to make a diagnostic of the system in terms of quality and efficiency and to present a plan in order to improve the quality and efficiency of the transit system. The main problems faced on the diagnostic were: inadequate space covering, overlapping of bus attendance, long headway between vehicles due to an exaggerate number of bus lines, absence of fare integration, deficient physical integration, low occupation of bus in non peak periods, bus traffic jam at bus stops due to inadequate schedule, huge delays in the central area due to traffic jam, lack of shelters at bus stops, etc. In the developed plan were proposed the following main actions: reorganization of the bus transit netword with reduction of the routes number and the elimination of overlapping of bus routes and the lacks of spatil covering service, reduction of the headway in the routes, implementation of a closed central station to promote physical and fare integration, pavement/rehabilitation of road pavement, improvement of system signs in bus streets, implementation of a rational operational programming, better distribution of the vehicles to the whole city; etc. In terms of efficiency, the main benefits of the proposed system are: fleet reduction 21%, total mileage reduction of 18% and operation cost reduction of 20%. Concerning to the quality, the main gains are: better space covering, small headway in the bus routes, travel time reduction, implementation of physical and fare integration, increase of the number of bus stops shelters, improvement of the rolling surface on bus streets, etc.
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Rinn, Bernd [Verfasser]. « Transport and aging in glassy systems = Transport und Altern in glasartigen Systemen / vorgelegt von Bernd Rinn ». Berlin : dissertation.de, 2002. http://d-nb.info/981087507/34.
Texte intégral
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Sanchez, Lotero Adriana Mercedes. « Thermal transport in strongly correlated electron systems ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1121946609637-03206.
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Stait-Gardner, Tim, Scott A. Willis, Nirbhay N. Yadav, Gang Zheng et William S. Price. « NMR diffusion measurements of complex systems ». Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-189360.
Texte intégralRésumé :
The pulsed gradient spin-echo nuclear magnetic resonance experiment is a powerful tool for studying the constitution and structure of complex systems (e.g., polydisperse systems and porous media). In applications to polydisperse systems, it is important to consider the effects of obstruction, exchange, entanglement, and diffusional averaging processes whereas in applications to porous samples, reliable structural information can only be extracted from the time-dependence of the apparent diffusion coefficient when the
deleterious effects of spatially and/or temporally inhomogeneous background (magnetic field) gradients can be suppressed. These issues are considered in this review.
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Momot, Konstantin I., David G. Regan et Philip W. Kuchel. « NMR diffusion experiments for complex systems ». Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196319.
Texte intégral