Dissertations / Theses: 'Trains'

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Shapochka, J. S., and N. O. Rudakova. "Maglev trains." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/45488.

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Maglev trains are wonderful inventions that fly on air. They use magnets to levitate and propel the trains forward. There is no friction between the train and the track! The batteries can levitate the train for 30 minutes without any additional energy. Linear generators in the magnets on board the train use the motion of the train to recharge the batteries.

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Heirich, Oliver [Verfasser]. "Localization of Trains and Mapping of Railway Tracks / Oliver Heirich." München : Verlag Dr. Hut, 2020. http://d-nb.info/1220567655/34.

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Sakuma, Yutaka. "Dynamics of trains and train-like articulated systems travelling in confined fluid." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102162.

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The dynamical stability, wave propagation, response, and mode localization in a train of flexibly interconnected rigid cylinders travelling in a confined cylindrical "tunnel" subjected to fluid dynamic forces are studied theoretically. Each cylinder, which is coupled and supported by springs and dampers, has two degrees of freedom of translational and rotational motions. The kinetic, dissipation, and potential energies of the system and the generalized forces associated with the fluid dynamic forces acting on the system, such as inviscid fluid dynamic forces, viscous frictional forces, and form drag, are obtained first. Then the equations of motion are derived by application of the Lagrange equation. The principal aim of this study is to investigate the effect of aerodynamic forces on the dynamics of a high-speed train running in a tunnel, or more generally of a train-like system travelling in a coaxial cylindrical tube.
The results of this study show that (a) the system loses stability by flutter; (b) viscous frictional drag has a considerable effect on stability; (c) when the aerodynamic forces act on the train, the frequency bands of the dispersion relation of wave propagation shift, and thus no classical normal modes (standing wave solutions) exist in the system; (d) the wavelength of the travelling sinusoidal force controls phase differences among cylinders in the train: and (e) the imperfections in the supporting springs have a great influence on mode localization and considerably alter the stability of the system.

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Sheng, Xiaozhen. "Ground vibrations generated from trains." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395945.

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Ritteman, Thomas Arthur. "Grains, Trains and Aqua-Mobiles." Thesis, North Dakota State University, 2010. https://hdl.handle.net/10365/29633.

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Grain shippers are constantly faced with making merchandising and logistical decisions while trying to achieve a positive net margin. They have to decide how much grain to sell and when the most opportune time to do so occurs. In addition, decisions regarding how much freight should be acquired and where grain should be shipped need to be addressed. These decisions are met by several sources of risk such as futures spreads, basis levels, transit times, equipment placements, and farmer deliveries. The primary objective of this thesis was to develop a model to determine both the optimal amount of grain that should be sold in the pipeline and the optimal amount of freight that should be hedged by grain shippers through the use of forward shipping mechanisms. Certificates of Transportation (COTs) offered by the Burlington Northern Santa Fe (BNSF) Railway were used to represent forward shipping mechanisms in this thesis. A stochastic simulation model of a prototypical grain shipper containing three country elevators and two export facilities was developed. A sensitivity analysis was conducted on merchandising and logistical variables to evaluate different scenarios. The analysis revealed that committing to too many shuttle COTS limited the shipper's flexibility, forced sales to be made in suboptimal periods, and significantly increased the level of demurrage. The type of freight ordering strategy implemented by each elevator ultimately determined the overall sustainability of the firm; shippers need to diversify the type of freight they commit to because ordering too much long-term freight can result in bad sales decisions, whereas relying only on short-term freight is costly and inefficient. Not being able to quickly adapt to volatile market conditions can result in making bad selling decisions and untimely freight purchases which can hinder the longevity of a firm.

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Heinz, Wiktoria. "Passenger service times on trains." Licentiate thesis, KTH, Infrastruktur, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1657.

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Wong, Wing-sum Angela. "Possibility of the development of high speed train between Hong Kong and Mainland China." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31627699.

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Lopez, Cédric. "Méthodes d'optimisation des trains d'atterrissage d'hélicoptère." Phd thesis, Paris, ENSAM, 2007. http://pastel.archives-ouvertes.fr/pastel-00003600.

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De récentes études expérimentales sur des situations d'atterrissage d'hélicoptères à grande vitesse dit dur (vitesse supérieure à 2 m/s), ont révélé que de par l'effort structural transmis par les trains d'atterrissage couplés mécaniquement au fuselage, la poutre de queue d'un appareil dont le premier mode de flexion se situe dans les basses fréquences pouvait être excitée. Les oscillations de celle-ci génèrent des contraintes mécaniques au niveau de la liaison entre la cabine et la poutre de queue qui portent atteinte à la pérennité de la structure. Afin de lutter contre ce phénomène problématique, une solution passive consiste à rigidifier la liaison entre la cabine et la poutre de queue. Coûteuse en masse et interférente avec le bon fonctionnement des dispositifs anti-vibratoires dimensionnés en fonction des fréquences propres initiales de l'appareil, celle-ci peut être évitée par une optimisation de l'effort transmis par les trains d'atterrissage en agissant sur le comportement dynamique de ceux-ci. Fort de ce constat, les travaux de recherche présentés dans ce mémoire, concernent l'étude et le développement de méthodes d'optimisation passive et active des trains d'atterrissage en vue de minimiser les efforts supportés par la poutre de queue et induits par l'impact de l'appareil sur le sol. Basé sur une constante synergie entre les aspects théoriques et les aspects expérimentaux appuyés par le développement d'un démonstrateur, cette étude formalise tout d'abord la problématique lié aux atterrissages des aéronefs et se propose d'analyser la physique du phénomène des atterrissages via des outils de modélisation utilisant des approches analytique et multi-corps. Ensuite après une analyse et une identification des paramètres d'optimisation de la dynamique des trains d'atterrissage, des méthodes d'optimisation passive et semi-active sont développées et validées expérimentalement sur un démonstrateur mécaniquement équivalent à l'hélicoptère considéré pour cette étude.

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Pratt, Ian. "Active suspension applied to railway trains." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/27621.

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There has been an impetus in recent years to increase railway train speeds and reduce journey times. As train speeds have increased, other problems have manifested themselves, in particular the consequent deterioration in ride quality at these higher operating speeds. Improvement in suspension design is one option which can circumvent this problem. Suspension design for a modem high-speed train has hitherto been a heuristic procedure directed towards optimising the passive components of the suspension. Performance limits are now being reached with passive suspensions due to the inherent trade-offs which need to be made in the design process. Active suspension, which eases this inherent trade-off, has received a great deal of interest in both academia and industry over recent years. A number of theoretical and experimental studies have highlighted the potential benefits of active suspension technology. Theoretical studies have concentrated on using simple vehicle models and although providing the initial impetus to active suspension they have not given the industry full confidence in them. In contrast, experimental studies have highlighted a number of problems, most notably the significant effect actuators can have on the overall performance.

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Peter, Marco. "The future of night trains. : JIYUKŪKAN." Thesis, Umeå universitet, Institutionen Designhögskolan, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-79499.

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Zolotas, Argyrios C. "Advanced control strategies for tilting trains." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/4279.

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The use of tilting bodies on railway vehicles is becoming increasingly widespread: a number of well-established services using tilt technology already exist around the world, and will appear again in the UK over the next year or so. The motivation for tilting railway vehicles is that they give a cost-effective means of achieving a substantial reduction in journey time by increasing the vehicle speed during curves. Early tilt controller designs were based upon local vehicle measurements, however at that time this approach did not prove very successful. Nowadays most European manufacturers use the so called ‘precedence' control scheme, utilising measurements from precedent vehicles to achieve ‘precedence' information. However, achieving a satisfactory local tilt control strategy is still an important research target because of the system simplifications and more straightforward failure detection. The thesis describes a comprehensive study of tilt control, and its aim is to employ advanced control techniques - based upon practical sensors - with the particular objective of identifying effective strategies which can be applied to each vehicle independently, i.e. without using precedence control. The sensors employed for control design are in particular mounted on the vehicle passenger coach. Most of the work has been undertaken using Matlab, and this has included a proper assessment of the ride quality issues.

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Alasali, Mohammad. "LTE MIMO Performance Measurements on Trains." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-108079.

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Providing passengers internet on board trains with continuous connectivity at high speeds and over large rural distances is a challenging issue. A promising solution to the problem is to use an on board WI-FI network combined with a cellular radio system connected to the LTE (long term evolution) 900/800MHz networks deployed outside the train. However, in order to reach the data rates that today's business traveller is expecting, \Multiple Input Multiple Output" (MIMO) may be needed. In this project the plausibility of achieving LTE MIMO functionality to moving trains is studied both theoretically and through measurements on a Swedish high speed train in a live LTE 900 network. The measurements were conducted along the main track between Stockholm and Gothenburg. Eight antennas were deployed at 4m height on the roof of a X2000 train that was moving at speeds between 100 and 200km/h. The average distance between the base stations and the track was 2.35km and the average base-station antenna height 45m. The measurement data was recorded using an LTE scanner provided by Rohde&Schwarz (TSMW). The simulations were conducted in Matlab and the above parameters were simulated for typical rural Line of Sight (LOS) radio channels. The simulation results show that MIMO may perform well on trains and reach higher rank in the above described radio channel, given that the inter-element distances are correctly chosen dependent on the base station-to-train distance. In the measurement a 2X2 MIMO system was tested and confirmed the model by showing that the condition number (CN), was less than 15 for 65% of the track covered by LTE. Hence, we find that it is indeed plausible to achieve MIMO functionality in LOS on the roof of a fast moving train. Furthermore, the report concludes that LTE-Advance with 8x8 MIMO functionality and carrier aggregation feature, may be a suitable solution in order to provide the internet capacity needed for all the passengers on board high speed trains.

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Lin, Qinhua. "Vibrations generated by underground railway trains." Thesis, Nottingham Trent University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396376.

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Abuzeid, Mustafa R. "Advanced braking control strategies for trains." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/32027.

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The thesis describes modelling methods that are being developed to support the design and evaluation of intelligent railway braking control systems. A particular feature is that the models include higher order vehicle and train dynamics, the effects of which are expected to become important as the performance of braking systems improve. The thesis describes mathematical techniques for modelling braking systems starting with braking of a single wheelset on its own, then a single braked wheelset in a bogie, followed by a single braked wheelset in a complete vehicle and finally four wheelsets braked in a complete vehicle. The mathematical model for the braking system combines the non-linear creep laws governing the braking forces generated between wheel and rail with the suspension dynamics of a typical high speed railway vehicle.

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Hedberg, Erik, and Mikael Hammar. "Train Localization and Speed Estimation Using On-Board Inertial and Magnetic Sensors." Thesis, Linköpings universitet, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-121620.

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Positioning systems for trains are traditionally based on track-side infrastructure, implying costs for both installation and maintenance. A reliable on-board system would therefore be attractive. Sufficient reliability for on-board systems is likely going to require a multi-sensor solution. This thesis investigates how measurements from bogie-mounted inertial and magnetic sensors can contribute to such a system. The first part introduces and compares two different methods for estimating the speed. The first one estimates the fundamental frequency of the variations in the magnetic field, and the second one analyses the mechanical vibrations using the accelerometer and gyro, where one mode is due to the wheel irregularities. The second part introduces and evaluates a method for train localization using magnetic signatures. The method is evaluated both as a solution for localization along a given track and at switchways. Overall, the results in both parts show that bogie-mounted inertial and magnetic sensors provide accurate estimates of both speed (within 0.5 m/s typically) and location (3-5 m accuracy typically).

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DOULCIER, LAURENT JEAN. "Insertion des lignes nouvelles t. G. V. En sites peri-urbains : proposition d'une methode d'etude d'impacts fondee sur l'elaboration de 15 classes qualitatives et une notation normalisee des parametres permettant la mise en oeuvre operationnelle d'un nouvel outil pour l'urbanisme." Paris 12, 1999. http://www.theses.fr/1999PA120035.

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Ce travail de recherche est une contribution, avec un certain souci d'application pratique, sur la facon d'aborder les etudes d'impacts en general, au travers de l'etude specifique du probleme de l'insertion des lignes nouvelles t. G. V. En site peri-urbains. Il s'appuie sur l'introduction paradoxale de la notion de classes qualitatives dans le continuum des composantes de l'urbanisme pour mieux l'apprehender en lui associant des instruments qualitatifs et quantitatifs qui jouent le role de mesures en apportant des aides a la decision dans les etudes comparatives. Des operations simples sur les classes permettent ensuite de qualifier des situations ou plusieurs criteres interviennent simultanement sans recourir a une mathematique compliquee de part la definition d'un nouveau concept operationnel, "l'hectare d'impact qualitatif", qui permet de mesurer l'intensite de la perte qualitative du site ou au contraire son eventuel gain qualitatif du fait d'un amenagement opportun par rapport a l'etat existant. Cette approche par classes et elements qualitatifs et semi-quantitatifs, permet a une grande diversite de profil de sensibilite de debattre sur des bases figuratives mettant en exergueles convergences et les divergences et d'etablir de ce fait, de veritables bases d'aides a la decision lors des indispensables choix. ___________________________________

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Malmassari, Paul. "Une expérience militaire "sous estimée" : les trains blindés français de la révolution industrielle à la décolonisation : étude technique et tactique comparée." Montpellier 3, 2007. http://www.theses.fr/2007MON30017.

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La guerre ferroviaire est née dès que l'intérêt du chemin de fer a été perçu par les militaires. L'idée du train blindé est contemporaine de la mise en service des premiers trains car la perspective nouvelle de pouvoir déplacer des masses d'hommes en cas de mobilisation, suscitait immédiatement l'intention de priver un adversaire potentiel de cet avantage décisif. Face à cette perspective, les trains bllindés (trains et automoteurs) ont fait assez tôt partie de la littérature ferroviaire en France, en Grande-Bretagne puis en Allemagne. Ils sont apparus pendant la guerre civile américaine avant d'être universellement reconnus lors de la guerre des Boers. Certains militaires et observateurs ont rapidement perçu combien la propulsion mécanique, alliée à une voie qui effaçait les irrégularités du terrain, pourrait permettre de construire des forts mobiles et bien armés. De fait, les trains blindés furent les premières machines de guerre automobiles terrestres viables avant les automitrailleuses et les chars. Avec l'apparition en masse des chars d'assaut, les trains blindés ont perdu leur rôle pionnier en guerre classique mais ont gagné en efficacité dans les guerres et le maintien de l'ordre outremer. Dans la contre-guérilla puis lors des guerres de décolonisation, les trains blindés ont maintenu le fonctionnement des réseaux ferrés vitaux pour la logistique et l'affichage politique. Cette étude a pour but de montrer, au-delà d'un oubli paradoxal, la place essentielle tenue par les trains blindés dans la genèse des blindés et principalement du char de combat, puis de montrer que cette arme fut indispensable à la conduite des guerres de la décolonisation
The war of the railroad was born with the interest shown by the Military. The idea of armoured trains, which occured at the same time than the running of the trains, was due to a new initiative for moving masses of men in case of mobilisation of forces, and it was intended to deprive a potential adversary of this decisive advantage. Consequently, armoured trains (trains and railcars) have rapidly been subject to writings on railroad in France, Great Britain and Germany. They came out during the American Civil war befor they knew universal recognition during the Boer War. Some military personnel and observers quickly saw the importance of motorisation which, combined with a track that corrected an uneven piece of land, could open the way to build mobile forts with well equipped armament. In fact, the armoured trains were the first feasible self-propelled war machines before the armoured cars and tanks. With the emergence of numerous tanks, armoured trains lost their pioneer role in regular warfare, but they gained efficiently in wars and internal security overseas. In counter guerilla wars and in wars on decolonisation, the armoured trains have kept the running of the railroad network, essential to logistics and political postings. The aim of this study is to show the highly important place the armoured trains occupied in the genesis of the armoured vehicles, specially with regards to the main battle tank. It also demonstrates that this weapon was essential to lead wars on decolonisation. It is truly a paradox to see that armoured trains have been since forgotten

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Copley, J. M. "The three-dimensional flow around railway trains." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355514.

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19

Persson, Rickard. "Tilting trains : Technology, benefits and motion sickness." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4771.

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Carbody tilting is today a mature and inexpensive technology allowing higher speeds in curves and thus reduced travel time. The technology is accepted by most train operators, but a limited set of issues still holding back the full potential of tilting trains. The present study identifies and report on these issues in the first of two parts in this thesis. The second part is dedicated to analysis of some of the identified issues. The first part contains Chapters 2 to 5 and the second Chapters 6 to 12 where also the conclusions of the present study are given.

Chapters 2 and 3 are related to the tilting train and the interaction between track and vehicle. Cross-wind stability is identified as critical for high-speed tilting trains. Limitation of the permissible speed in curves at high speed may be needed, reducing the benefit of tilting trains at very high speed. Track shift forces can also be safety critical for tilting vehicles at high speed. An improved track standard must be considered for high speed curving.

Chapters 4 and 5 cover motion sickness knowledge, which may be important for the competitiveness of tilting trains. However, reduced risk of motion sickness may be contradictory to comfort in a traditional sense, one aspect can not be considered without also considering the other. One pure motion is not the likely cause to the motion sickness experienced in motion trains. A combination of motions is much more provocative and much more likely the cause. It is also likely that head rotations contribute as these may be performed at much higher motion amplitudes than performed by the train.

Chapter 6 deals with services suitable for tilting trains. An analysis shows relations between cant deficiency, top speed, tractive performance and running times for a tilting train. About 9% running time may be gained on the Swedish line Stockholm – Gothenburg (457 km) if cant deficiency, top speed and tractive performance are improved compared with existing tilting trains. One interesting conclusion is that a non-tilting very high-speed train (280 km/h) will have longer running times than a tilting train with today’s maximum speed and tractive power. This statement is independent of top speed and tractive power of the non-tilting vehicle.

Chapters 7 to 9 describe motion sickness tests made on-track within the EU-funded research project Fast And Comfortable Trains (FACT). An analysis is made showing correlation between vertical acceleration and motion sickness. However, vertical acceleration could not be pointed out as the cause to motion sickness as the correlation between vertical acceleration and several other motions are strong.

Chapter 10 reports on design of track geometry. Guidelines for design of track cant are given optimising the counteracting requirements on comfort in non-tilting trains and risk of motion sickness in tilting trains. The guidelines are finally compared with the applied track cant on the Swedish line Stockholm – Gothenburg. Also transition curves and vertical track geometry are shortly discussed.

Chapters 11 and 12 discusses the analysis, draws conclusions on the findings and gives proposals of further research within the present area.

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Connolly, David. "Ground borne vibrations from high speed trains." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8302.

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A consequence of high speed rail transportation is the generation of elevated ground borne vibrations. This thesis presents several original contributions towards the prediction of these vibrations. Firstly, a new three dimensional finite element model capable of vibration prediction was developed. Its main feature was its ability to model complex track geometries while doing so through a fully coupled vehicle-tracksoil system. Model output was compared to experimental results obtained during this thesis and also to independent data sets. It was shown to predict velocity time histories, vibration frequency spectrums and international vibration descriptors with high accuracy. An appraisal of the suitability of a finite difference time domain modelling approach for railway vibration prediction was also undertaken. This resulted in the development of a new ‘higher order’ perfectly matched layers absorbing boundary condition. This condition was found to offer higher performance in comparison to current alternative absorbing boundary conditions. Field work was then undertaken on high speed lines with varying embankment conditions in Belgium and England. Vibration data was recorded up to 100m from each track and geophysical investigations were performed to determine the underlying soil properties. The results were used for numerical model validation and also to provide new insights into the effect of various embankment conditions on vibration propagation. It was found that embankments generate higher frequency excitation in comparison to nonembankment cases and that cuttings generate higher vibration levels than noncuttings. Once validated the finite element model was used to provide new insights into the effect of train speed, embankment constituent materials and railway track type on vibration levels. It was found that the shape and magnitude of ground vibration increased rapidly as the train’s speed approached the Rayleigh wave speed of the underlying soil. It was also found that ballast, slab and metal tracks produced similar levels of vibration and that stiffer embankments reduced vibration levels at distances near and far from the track. Two vibration mitigation techniques were also explored through numerical simulation. Firstly, an analysis was undertaken to determine the ability of a new modified ballast material to actively isolate vibration within the track structure. Secondly, wave barrier geometries were investigated to optimise their performance whilst minimising cost. It was found that barrier depth was the most influential parameter, whereas width had little effect. Additionally, geometry optimisation was found to result in a 95% cost saving in comparison to a base case. Using a vast array of results generated using the previously developed finite element model, a new empirical prediction model was also developed, capable of quickly assessing vibration levels across large sections of track. Unlike currently available empirical models, it was able to account for soil properties in its calculation and could predict a variety of international vibration metrics. It was shown to offer increased prediction performance in comparison to an alternative empirical model.

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Robinson, C. G. "The effect of atmospheric turbulence of trains." Thesis, University of Nottingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235563.

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Brockie, N. J. W. "The aerodynamic drag of high speed trains." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234147.

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Emhemmed, Yousef Mohammed. "Maximum likelihood analysis of neuronal spike trains." Thesis, University of Glasgow, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326019.

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Mahmod, Shad. "Deinterleaving pulse trains with DBSCAN and FART." Thesis, Uppsala universitet, Avdelningen för systemteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-379718.

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Studying radar pulses and looking for certain patterns is critical in order to assess the threat level of the environment around an antenna. In order to study the electromagnetic pulses emitted from a certain radar, one must first register and identify these pulses. Usually there are several active transmitters in anenvironment and an antenna will register pulses from various sources. In order to study the different pulse trains, the registered pulses first have to be sorted sothat all pulses that are transmitted from one source are grouped together. This project aims to solve this problem, using Density-Based Spatial Clustering of Applications with Noise (DBSCAN) and compare the results with those obtained by Fuzzy Adaptive Resonance Theory (FART). We aim to further dig into these methods and map out how factors such as feature selection and training time affects the results. A solution based on the DBSCAN method is proposed which allows online clustering of new points introduced to the system. The methods are implemented and tested on simulated data. The data consists of pulse trains from simulated transmitters with unique behaviors. The deployed methods are then tested varying the parameters of the models as well as the number of pulse trains they are asked to deinterleave. The results when applying the models are then evaluated using the adjusted Rand index (ARI). The results indicate that in most cases using all possible data (in this case the angle of arrival, radio frequency, pulse width and amplitudes of the pulses) generate the best results. Rescaling the data further improves the result and tuning the parameters shows that the models work well when increasing the number of emitters. The results also indicate that the DBSCAN method can be used to get accurate estimates of the number of emitters transmitting. The online DBSCAN generates a higher ARI than FART on the simulated data set but has a higher worst case computational cost.

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Majala, Jonas. "Frequency analysis of accelerometer measurements on trains." Thesis, Luleå tekniska universitet, Geoteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63930.

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Montague, R. G. "Control of drive trains incorporating magnetic gears." Thesis, University of Sheffield, 2011. http://etheses.whiterose.ac.uk/2304/.

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This is a thesis about the control of magnetic gears. A decade ago (2001) the first modern prototype magnetic gear box was constructed using rare earth magnets (NdFeB). Magnetic gear boxes have some desirable properties not found in their mechanical gear box counterparts, these include: contact-less torque transmission, lubrication-free, reduced noise and vibration, and non-destructive torque overload capability. Hitherto, no detailed investigation or analysis has been conducted on the effects of using a magnetic gear box in place of a mechanical gear box. As will be demonstrated in this thesis, magnetic gears possess a number of undesirable properties which must be given due consideration when designing speed and position controllers. In particular, unlike mechanical gear boxes, magnetic gear boxes have extremely low torsional rigidity. Furthermore, the torque transfer characteristic is fundamentally nonlinear and magnetic gear boxes have the potential to 'slip'. On the one hand, 'slipping' is a great benefit as a non-destructive 'torque fuse'; but on the other, this represents a consequential loss of control. This thesis examines the control issues that arise through the use of a specially constructed magnetic coupling integrated into an experimental test rig. The development of a linearized mathematical model of the experimental magnetic coupling is used to derive optimized classical controllers for speed and position, demonstrating outstanding theoretical and experimental results. To compensate for the possibility of 'slip', a methodology is presented for the detection and recovery from what is defined as 'pole-slip' in a magnetic coupling. To avert 'pole-slip', a model predictive control (MPC) scheme is developed that prevents over-torque pole-slipping. Feedback linearization is considered for a nonlinear model of the magnetic coupling and nonlinear control laws and state transformations are derived to produce perfect linearization, for both speed and position control, over the entire operating range of the experimental magnetic coupling.

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Chelouati, Mohammed. "Contributions to safety assurance of autonomous trains." Electronic Thesis or Diss., Université Gustave Eiffel, 2024. http://www.theses.fr/2024UEFL2014.

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Le déploiement des trains autonomes soulève de nombreuses questions et défis, notamment ceux liés au niveau de sécurité visé, qui doit être globalement au moins équivalent à celui du système existant, ainsi que les moyens à mettre en œuvre pour l'atteindre. Conventionnellement, la mise en sécurité d'un système ferroviaire global ou d'un sous-système défini comprend une phase d'analyse des risques et une phase de maîtrise des situations dangereuses. Ainsi, pour tout système technique ferroviaire, qu'il soit classique, automatique ou autonome, un niveau de sécurité acceptable doit être assuré. Dans le contexte des trains autonomes, les défis liés à leur sécurité incluent les aspects émergents de l'intelligence artificielle, le transfert de tâches et de responsabilités du conducteur vers des systèmes décisionnels automatiques, ainsi que les aspects liés à l'autonomisation, tels que la transition entre les modes et la gestion des modes dégradés. La méthodologie de démonstration de sécurité des trains autonomes, doit ainsi prendre en compte les risques engendrés par l'ensemble de ces aspects. Autrement dit, elle doit définir l'ensemble les activités de sécurité (liées à l'introduction de l'autonomie et des Systèmes d'Intelligence Artificielle), complémentaires à la démonstration de sécurité conventionnelle. Dans ce cadre, l'objectif de cette thèse est de contribuer à l'élaboration d'une démarche d'assurance de sécurité pour les trains autonomes. Concrètement, cette thèse propose trois contributions principales. Premièrement, nous proposons une méthodologie globale de haut niveau pour la structuration et la présentation de l'argumentation de sécurité pour les trains autonomes. La méthodologie est basée sur une approche orientée objectifs de sécurité (goal-based safety) en utilisant le formalisme graphique GSN (Goal Structuring Notation). Ensuite, nous proposons une modélisation de la conscience de situation (situational awareness) d'un système de conduite autonome d'un train, intégrant le processus de l'analyse dynamique des risques ferroviaires. Ce modèle permettra au système de conduite autonome de percevoir, de comprendre, d'anticiper et de s'adapter à des situations inconnues dans son environnement tout en prenant des décisions sûres. Le modèle est illustré à travers un cas d'étude concernant la détection et l'évitement d'obstacles sur la voie ferroviaire. Dernièrement, nous élaborons une approche de prise de décision basée sur l'évaluation dynamique des risques. L'approche utilise le Processus Décisionnel de Markov Partiellement Observable (POMDP) et vise à assurer une surveillance continue de l'environnement pour garantir la sécurité opérationnelle, en particulier la prévention des collisions. L'approche repose sur le maintien d'un niveau de risque acceptable grâce à une estimation et une actualisation continues de l'état opérationnel du train et des données de perception de l'environnement
The deployment of autonomous trains raises many questions and challenges, particularly concerning the required safety level, which must be globally at least equivalent to that of the existing systems, along with how to achieve it. Conventionally, ensuring the safety of a global railway system or a defined subsystem includes analyzing risks and effectively handling dangerous situations. Therefore, for any technical railway system, whether it is conventional, automatic, or autonomous, an acceptable level of safety must be ensured. In the context of autonomous trains, safety challenges include aspects related to the use of artificial intelligence models, the transfer of tasks and responsibilities from the driver to automatic decision-making systems, and issues related to autonomy, such as mode transitions and management of degraded modes. Thus, the safety demonstration methodology for autonomous trains must take into account the risks generated by all these aspects. In other words, it must define all the safety activities (related to the introduction of autonomy and artificial intelligence systems), complementary to conventional safety demonstration. In this context, this dissertation proposes three main contributions towards the development of a safety assurance methodology for autonomous trains. Firstly, we establish a high-level framework for structuring and presenting safety arguments for autonomous trains. This framework is based on a goal-based approach represented by the graphical modeling Goal Structuring Notation (GSN). Then, we propose a model for the situational awareness of the automated driving system of an autonomous train, that integrating the process of dynamic risk assessment. This model enables the automated driving system to perceive, understand, anticipate and adapt its behavior to unknown situations while making safe decisions. This model is illustrated through a case study related to the obstacle detection and avoidance. Finally, we develop a decision-making approach based on dynamic risk assessment. The approach is based on Partially Observable Markov Decision Processes (POMDP) and aims to ensure continuous environmental monitoring to guarantee operational safety, particularly collision prevention. The approach is based on maintaining an acceptable level of risk through continuous estimation and updating of the train's operational state and environmental perception data

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Mellier, Carine. "Optimal Design of Bridges for High-Speed Trains : Single and double-span bridges." Thesis, KTH, Bro- och stålbyggnad, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-36354.

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To deal with an increasing demand in transportation, trains are made longer and faster. Higher speeds imply higher impacts on bridges. Therefore, structures have to be designed to resist these new constraints. The Eurocode (2002) introduced additional checks for the design of high-speed railway bridges. Among them, the maximum vertical deck acceleration criterion often determines alone the design of the structure. Tests on shake table brought to the conclusion that vertical bridge deck acceleration should never exceed 3.5 m/s2 for ballasted tracks. This master thesis investigates the optimization of cross section parameters of single-track simply supported and double-span bridges based on the limit of the maximum vertical deck acceleration criterion. The first natural frequency is considered as a proof of the feasibility of the structure. The optimization is carried out through MATLAB for both types of bridges. The deck acceleration of simply supported bridges is analytically calculated using the Train Signature (ERRI D214 1999) in MATLAB. The dynamic calculations of double-span bridges are implemented through the finite element software ABAQUS. The implemented programs have been verified by comparison to values of simple cases found in the literature. Structures are tested under the influence of the ten HSLM-A trains of the Eurocode running at speeds between 150 km/h and 350 km/h. Optimization algorithms are presented and compared in this study but their applicability in such context is questioned. Indeed, as the problem contains several suitable minima, the algorithms, which end in one solution, are not adapted. To overtake this difficulty, a scanning of the interesting zone is advised. However, the latter is very time consuming, even more if the finite element analysis is used. Suggestions to decrease analysis time are presented in this report. Single span composite bridges with a span longer than 20 m appeared to be impossible to optimize within the objectives defined in this work (i.e. considering limits of deck acceleration and first natural frequency), which draws doubts about their suitability for high-speed railways. Nevertheless, simply supported bridges made of concrete seem more adapted for high-speed railways and their optimized parameters are presented in this work. Optimized parameters for double-span concrete bridges are also presented.

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Lee, Kyung-Chul. "Le train à grande vitesse comme outil d'aménagement du territoire et d'aménagement urbain en France et en Corée." Paris 4, 2000. http://www.theses.fr/2000PA040072.

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Le train à grande vitesse est considéré comme un outil efficace de l'aménagement du territoire et de l'aménagement urbain en France et en Corée. L'analyse et la comparaison des effets attendus du TGV et du HSR, et l'évaluation des projets d'aménagement des quartiers des gares TGV déjà réalisées en France apportent des enseignements utiles pour le projet HSR Séoul Pusan actuellement en réalisation pour le projet HSR Seoul Mokp’o prévu en 2020. Pourtant l'idée de développer un train à grande vitesse sur tout le territoire pour favoriser l'aménagement du territoire n'apparait pas pertinente, compte tenu du faible effet du TGV sur la décentralisation des fonctions directionnelles, de la lourdeur des investissements et de la dégradation des dessertes régionales qu'il entraine. En effet, l'effet attendu du train à grande vitesse sur l'aménagement urbain s'oppose à la logique de la grande vitesse, qui se soucie principalement d'un gain de temps maximal sur les liaisons entre villes importantes, et qui se traduit par un emplacement périphérique des gares du train à grande vitesse. Le TGV, seul, ne suffit pas à transformer les rigidités inhérentes aux quartiers des gares. Les projets d'aménagement français et coréens, qui visent à remodeler ces quartiers en négligeant leur hétérogénéité essentielle, sont donc problématiques. En conclusion, l'articulation du train à grande vitesse avec le rail classique est la condition sine qua non pour que le train à grande vitesse ait des effets sur l'aménagement du territoire et sur l'aménagement urbain.

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王穎琛 and Wing-sum Angela Wong. "Possibility of the development of high speed train between Hong Kong and Mainland China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31627699.

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Mzali, Myriam. "Perception de l'ambiance sonore et évaluation du confort acoutsique dans les trains." Paris 6, 2002. http://www.theses.fr/2002PA066447.

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Arif, Nadia. "Etude du comportement des trains d'atterrissage d'avions légers." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0522.

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Les avions légers sont conçus pour être utilisés dans les zones reculées d'un pays, où les infrastructures de transport sont inadéquates ou inexistantes. Ils peuvent atterrir sur différents types de piste (glace, gravier, sable, gros cailloux...). Le problème principal de ces avions est le défaut d’absorption d’énergie cinétique à l’atterrissage, bien qu'une partie des énergies de choc soit absorbée par les pneumatiques sous-gonflés. Des chocs et des rebonds peuvent se produire mettant en péril la sécurité de l’avion et des passagers. Le but de ce travail est de développer un outil numérique qui permet de modéliser les trains d'atterrissage, de prévoir leur réponse dynamique dans des conditions extrêmes, et de comparer leur capacité à dissiper l’énergie à la rencontre des obstacles. Étant donné son rôle primordial dans l'absorption des chocs, une étude expérimentale est dédiée à la caractérisation du pneumatique de brousse. Cette étude permet de construire un modèle éléments finis détaillé du pneumatique en prenant en compte la géométrie et la structure matérielle complexe. Une deuxième partie est consacrée à la modélisation numérique de quatre systèmes de trains d'atterrissage (existants ou proposés). De nombreuses simulations de roulement sont réalisées afin d'étudier, d'une part l'influence des conditions de roulement et l'influence de la taille et de la forme de l'obstacle d'autre part. L'analyse des amplitudes des efforts et des rebonds transmis à l'avion au cours du roulement permet d'évaluer les réponses dynamiques des différents trains et de comparer leur efficacité de dissipation
Light aircraft, such as bush planes, are designed for use in undeveloped areas of a country where transport infrastructure is inadequate or non-existent. They can land on different types of runways (ice, gravel, sand, big stones ...). The main problem with these aircraft is the lack of kinetic energy absorption at landing, although some of the shock energy is absorbed by the underinflated tires. Hard landing conditions such as shocks and rebounds may occur and endanger the safety of the aircraft and passengers. The aim of this work is to develop an efficient numerical tool for studying landing gear systems, predict their dynamic response in extreme conditions, and compare their energy dissipation. Given its primary role in shock absorption, an experimental study is dedicated to the characterization of the bush tire. Then, a detailed finite element model of the tire is developed, taking into account real geometry and material specificities. A second part is devoted to the numerical modeling of the different systems of landing gears (existing and proposed). Combined finite elements with structural elements are used. Thus, stress, deformation and energy within landing gears components could be obtained. Multiple dynamic rolling simulations are carried out in order to study, not only the influence of the rolling conditions (such as rolling velocity, tires inflation pressure, etc.), but also the influence of the size and the shape of obstacles. Systems' transient responses while rolling over ramp are evaluated, as well as the efforts and rebound displacements transmitted to the aircraft. A dissipation efficiency comparative study between the landing gears is conducted

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Förstberg, Johan. "Ride comfort and motion sickness in tilting trains." Doctoral thesis, KTH, Vehicle Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2985.

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Venkatasalam, Nachiyappan. "Crosswind assessment of trains on different ground configurations." Thesis, KTH, Järnvägsteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129712.

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Cross wind analysis is one of the important safety measures for rail vehicle certification. The objective of this study is to identify which vehicle certification ground setup, true flat ground (TFG) or single track ballast and rail (STBR) represents a more realistic ground setup with atmospheric boundary layer (ABL) wind inlet and also to represent an embankment scenario. A streamlined high speed train ICE3 and a conventional Regional train are taken for the analysis to represent both categories. CFD is used as a tool for calculations. The best practice recommended by the AeroTRAIN project is used for the CFD approach. The analysis is done for various configurations including STBR, TFG, embankments, ground roughness, moving ground, non-moving ground, block profile inlet, ABL inlet, model scale and full scale setups. The Regional train shows higher roll moment coefficient about lee rail (Cmx,lee) compared to the ICE3 train, whereas the ICE3 train has a higher lift force coefficient than the Regional train. STBR setup shows a higher force and moment coefficient compared to TFG. The STBR setup represents the more realistic setup of moving rough ground with ABL wind inlet and also the realistic embankment scenario.

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Johnson, David M. "Simulation of clearances between trains and the infrastructure." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445170.

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Trains need to be bigger and faster, which places strains on the interface between them and the infrastructure. This thesis examines the nature of one of these interfaces, namely clearance or gauging. There is little published work on the management of clearances beyond regulatory documents. This thesis considered many aspects of the engineering of clearance to develop a mathematic simulation of the gap between moving trains and the infrastructure. It proposes the concept of replacing gauge clearance with a comparison between measured infrastructure and dynamic simulations of trains. The thesis follows four themes. A model is developed which allows the swept envelope of a moving train to be calculated, using simulation techniques. This is followed by an examination of infrastructure measuring methods and the development of a measuring system for determining the size and shape of the railway network. Finally, the modelling process is used to determine the maximum size of train that may run on specific routes by optimising the fit between train and infrastructure.

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Del, Valle Perez-Solero Nahia. "Measurement and analysis of slipstreams for passenger trains." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3790/.

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This thesis presents a new experimental technique to determine the structure of train slipstreams. The highly turbulent, non stationary nature of slipstreams make their measurement difficult and time consuming as in order to identify the trends of behaviour several passages of the train have to be made. The new technique has been developed in order to minimise considerably the measuring time. It consists of a rotating rail rig to which a 1/50th scale model of a train is attached. Flow velocities are measured using two multi-hole Cobra probes, positioned close to the sides and top of the model. Tests were carried out at different model speeds. Velocity time histories for each configuration were obtained from ensemble averages of the results of a large number of runs (of the order of 80). From these it was possible to define velocity and turbulence intensity contours along the train as well as the displacement thickness of the boundary layer, allowing a more detailed analysis of the flow. Wavelet analysis was carried out on the experimental data to reveal details of the unsteady flow structure around the vehicle. It is concluded that, although this methodology introduces some problems the results obtained with this technique are in good agreement with previous model and full scale measurements.

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Lundin, Emil, and Johan Bergelin. "HETEROGENEOUS BATTERY SYSTEMS IN BATTERY EQUIPPED PASSENGER TRAINS." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-54482.

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The rise of batteries in the industry, especially Li-ion, is increasing rapidly. Li-ion battery systems are traditionally composed of a particular type of cell chemistry fit to the system needs. Due to the significant differences between chemistries, different cells have different attributes. The thesis explores the potential of a heterogeneous solution to include different cells to find a suitable compromise between different attributes. An electrified passenger train using a homogenous solution was evaluated against a heterogeneous solution consisting of two cell types, NMC and LTO, which have significant differences in attributes. Simulation with models covering the train kinematics, track characteristics, and battery behaviour generates the thesis results. Validation of simulation results includes comparing previous simulations and the new effects of the heterogeneous solution, which indicate a good fit. Verification of the results encompasses a small-scale experiment with a custom-made physical circuit to observe the proposed solution's actual behaviour and verify model validity, which implies the correctness of models and implementation. The results indicate that a heterogeneous solution is possible within the scope of electrified trains. Furthermore, several trade-offs exist between NMC and LTO cells, especially regarding rate capability, safety and capacity, which confirms the potential of heterogeneous battery systems.

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Mehboob, Zareen. "Information quantification for spike trains and field potentials." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/information-quantification-for-spike-trains-and-field-potentials(41093f37-7838-41bc-aeb4-1d45f34e2bb8).html.

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Neural signals are recorded from various regions of the brain and are analysed to understand the working mechanism of neurons and how they interpret external environment. The aim is to understand how this nature's supercomputer works. This helps in exploring human systems and intelligence, treat mental conditions and develop smart machines. Neural data recordings are collected from individual neurons and from populations of neurons. The single neuronal activity recordings are spike train and the activity generated from multiple neurons are field potentials. The data obtained are in enormous amount and of millisecond precision, as a consequence their processing is not a trivial task and efficient techniques are required for decoding these datasets. This work proposes several methods for the analysis of spike train and field potentials. A self-organising map based clustering is applied to synchronous spike train and generates topographically ordered and information-preserving clusters that help interpret how stimuli features are encoded by the neurons. An information-coupled empirical mode decomposition framework is developed for field potentials. It extracts informative oscillatory functions and information coding frequency bands in the recordings. This has several applications. The informative modes reveal underlying neuronal activities w.r.t stimuli, which otherwise have to be extracted by bandpass filters, followed by Fourier or wavelets analysis. It can also be used to analyse neuronal population activity under a medical condition or to understand neuronal interactions by information-connectivity analysis among electrodes. The proposed framework is developed into the form of a toolbox which can be used for educational and research purposes.

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Bajer, Andrzej. "Parallel finite element simulator of planetary gear trains." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3032969.

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Ishrat, Tajrin. "Slip control for trains using induction motor drive." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/199908/1/Tajrin_Ishrat_Thesis.pdf.

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This research is a railway industry related project, which is concerned with finding improvements in railway traction and wheel slip control in electric drives. A new approach was developed to detect the unknown and immeasurable rail surface. And a novel identification scheme was used to identify the best operating friction level. A new switching controller was operated by the induction motor controller under all possible train operating conditions. Aspects of the study were validated in the laboratory experiment. By exploring the in-rail track condition detection, the best drive torque and desired slip in the railway field were identified.

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Selhi, Hocine. "Simulation of transients in AC traction systems." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282843.

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Yang, Geon-Seok. "Les enjeux de la construction des voies ferrées rapides : de l'expérience française et européenne, au développement du KTX coréen." Paris 7, 2009. http://www.theses.fr/2009PA070022.

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Notre étude analyse l'influence de la construction des voies ferrées rapides sur l'orientation stratégique des plans et des politiques d'aménagement du territoire en France, en Europe, et en Corée du Sud. Beaucoup de zones urbaines économiques sont modifiées par leur position dans la hiérarchie territoriale selon l'état de leur raccordement avec le réseau ferroviaire à grande vitesse. C'est tout d'abord la concentration qui est l'effet le plus important de la construction de ces réseaux (TGV, KTX). En second lieu, il est montré comment le développement d'un réseau de transport concentré dans la région de Paris et de Séoul a eu l'effet d'un facteur intensifiant en ce qui concerne les accessibilités aux zones métropolitaines. Mais ce système a créé un risque d'augmentation du déséquilibre territorial, en France comme en Corée du Sud. En troisième lieu, les zones d'activité économique autour des nouvelles gares apparaissent avoir contribué au passage d'une organisation mono-polarisée à une organisation multi-polarisée. Enfin, l'intégration du système à grande vitesse a augmenté la concentration de l'activité économique dans certaines zones métropolitaines européennes, chacune de ces zones essayant de développer un espace plus concurrentiel lui permettant de s'élever dans la hiérarchie urbaine globale. En conclusion, en dépit de contextes nationaux très différents, on a constaté un niveau important de correspondances entre les cas étudiés, au niveau des concepts stratégiques et des arguments
Our study analyzes the influence of the construction of the High Speed Railways on the strategic direction of the plans and policies of town and country planning in France, in Europe, and in South Korea. There are many economic urban areas which are modified by their position in the territorial hierarchy according to the condition of their connection with the High Speed Railway network. First of all, concentration is the most important effect produced by the construction of these networks (TGV, KTX). Second, it is shown how the development of a network System concentrated in the areas of Paris and Seoul had the effect of an intensifying factor regarding accessibilities to the metropolitan zones. This System has nevertheless created the risk of an increasing territorial imbalance, in France as well as in South Korea. Third, the zones of economic activity located around the new high speed railway stations appear to have contributed to the passage from a mono-polarized organization to a multi-polarized one. Lastly, the integration of the high speed railway System increased the concentration of the economic activity in European metropolitan zones, each one of these zones trying to develop a more competitive space for ascending in the global urban hierarchical System. In conclusion, in spite of the great differences in the national contexts, an important rate of correspondences between the studied cases could be noted regarding strategic concepts and arguments

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Förstberg, Johan. "Ride comfort and motion sickness in tilting trains : human responses to motion environments in train and simulator experiments /." Stockholm, 2000. http://www.lib.kth.se/Fulltext/forstberg000606.pdf.

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Malvestio, Irene. "Detection of directional interactions between neurons from spike trains." Doctoral thesis, Universitat Pompeu Fabra, 2019. http://hdl.handle.net/10803/666226.

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An important problem in neuroscience is the assessment of the connectivity between neurons from their spike trains. One recent approach developed for the detection of directional couplings between dynamics based on recorded point processes is the nonlinear interdependence measure L. In this thesis we first use the Hindmarsh-Rose model system to test L in the presence of noise and for different spiking regimes of the dynamics. We then compare the performance of L against the linear cross-correlogram and two spike train distances. Finally, we apply all measures to neuronal spiking data from an intracranial whole-night recording of a patient with epilepsy. When applied to simulated data, L proves to be versatile, robust and more sensitive than the linear measures. Instead, in the real data the linear measures find more connections than L, in particular for neurons in the same brain region and during slow wave sleep.
Un problema important en la neurociència és determinar la connexió entre neurones utilitzant dades dels seus trens d’impulsos. Un mètode recent que afronta la detecció de connexions direccionals entre dinàmiques utilitzant processos puntuals és la mesura d’interdependència no lineal L. En aquesta tesi, utilitzem el model de Hindmarsh-Rose per testejar L en presència de soroll i per diferents règims dinàmics. Després comparem el desempenyorament de L en comparació al correlograma lineal i a dues mesures de trens d’impulsos. Finalment, apliquem totes aquestes mesures a dades d’impulsos de neurones obtingudes de senyals intracranials electroencefalogràfiques gravades durant una nit a un pacient amb epilèpsia. Quan utilitzem dades simulades, L demostra que és versàtil, robusta i més sensible que les mesures lineals. En canvi, utilitzant dades reals, les mesures lineals troben més connexions que L, especialment entre neurones en la mateixa àrea del cervell i durant la fase de son d’ones lentes.

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Thomas, Dirk. "Lateral Stability of High-Speed Trains at Unsteady Crosswind." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11377.

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Crosswind stability of rail vehicles has been a research area for several decades,mainly motivated by vehicle overturning accidents and higher speeds, but in recenttimes also by issues of lower energy consumption and track maintenance costsdemanding lower vehicle weights. During everyday operation, rail vehicles are subjectedto large lateral influences from track irregularities, track curves and crosswind,leading to large suspension deflections and increased crosswind sensitivity.Also unsteady crosswind like gusts calls for attention. Simulations of possible vehicleoverturning are necessary, but need to take large deflections and high shear inthe suspension into account. If delivering reasonable results, simulations representan important tool for overturning prediction of the vehicle.

In the present work, multibody simulations of a high-speed vehicle at large lateralinfluences from track curves and track irregularities have been carried out, using ahalf-vehicle model in 2D and a model of a whole vehicle in 3D. The vehicle modelsalso include different suspension models. Corresponding field measurements ofthe relative lateral and vertical deflections in the secondary suspension have beenperformed on a fast train and used for validation of the multibody simulations,resulting in good agreement between measurements and simulations.

The 3D vehicle model was further used to study the vehicle response to unsteadycrosswind during curve negotiation where aerodynamic loads obtained by unsteadyComputational Fluid Dynamics, namely Detached Eddy Simulations, representingthree types of gusts were used. In addition, the method of Quasi Transient GustModelling was evaluated in terms of overturning risk. Strong lateral and roll responsesof the vehicle and influences of the gust duration and the relative differencebetween mean and maximum wind speed were observed. Further, variations of suspensionand mass properties of the vehicle were performed to study the influenceon crosswind sensitivity. The position of the centre of mass of the carbody and thelateral bumpstop clearance showed significant influence on the crosswind stability.

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程遠勝 and Yuansheng Cheng. "Vibration analysis of bridges under moving vehicles and trains." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3124001X.

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Kay, Alison Lindsey. "Travelling fronts and wave-trains in reaction-diffusion equations." Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342513.

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Amara-Korba, Enwer. "Optimal sequence and heat integration for multicomponent distillation trains." Thesis, University of Sheffield, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340894.

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Ng, S. L. D. "Transmission of ground-borne vibration from surface railway trains." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243156.

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Gilbert, Timothy. "Aerodynamic effects of high speed trains in confined spaces." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4748/.

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This research aims to describe the effect which changing the geometry of confining structures has on transient aerodynamic effects induced by passing high-speed trains. A moving-model high-speed train was fired past walls, partially-enclosed tunnels, and single-track tunnels. A control experiment was carried out in the open air. 3D air velocity components and static pressure were measured inside the structures. The main findings are as follows. The durations and magnitudes of the pressure loads and maximum air velocities were found to be dependent on: the lateral separation of the walls; whether walls on both sides of the tracks are placed symmetrically or asymmetrically; the longitudinal positioning of the sensor in relation to the length of the tunnel; the cross-sectional area of the tunnel; the tunnel’s length in relation to the train’s length; and, finally, the size of an opening in the cross-section of a tunnel in relation to the tunnel’s internal perimeter. Maximum velocities were affected by confinement as a result of changes to: helical vortices in the wake; durations and magnitudes of the pressure fluctuation around the tail; the piston effect in tunnels; the boundary layer shape; and secondary flows induced by pressure gradients in the tunnel cross-section caused by vents.

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Dissertations / Theses on the topic 'Trains'

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