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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Modellierung, Simulation und Bewertung parallel-hybrider Antriebskonfigurationen für dieselhydraulische Triebwagen im Nah- und Regionalverkehr

Kache, Martin 03 June 2014 (has links)
Ausgangspunkt der Untersuchung ist die Frage, ob Hybridkonzepte auf hydrostatischer Grundlage eine realistische Alternative zu elektrohybriden Antriebskonfigurationen für Dieseltriebwagen sein können. Die Untersuchung dieser Fragestellung erfolgt mit Hilfe von Simulationsmodellen, die auf der 1-d-Simulationsumgebung Imagine.Lab AMESim beruhen. Zunächst wird die fahrdynamische und antriebstechnische Modellierung eines dieselhydraulischen Regionaltriebwagens unter Berücksichtigung einer energiesparenden Fahrweise dargestellt. Ausgehend von Massenbilanzen werden untereinander vergleichbare Hybridkonfigurationen auf hydrostatischer (Gasdruckspeicher), elektrostatischer (Doppelschichtkondensatoren) und elektrochemischer (Li-Ionen-Speicher) Basis entwickelt. Die Modellierung der hydraulischen und elektrischen Antriebsstränge wird eingehend diskutiert. Die abgeleiteten Hybridkonfigurationen werden anschließend bezüglich spezieller Fahrspiele und Betriebskonzepte detailliert untersucht, um auf dieser Grundlage günstige Parametrierungen der Systeme ableiten und die günstigste Betriebsstrategie identifizieren zu können. Anschließend wird eine umfangreiche Analyse des Verhaltens der verschiedenen Hybridkonfigurationen auf ausgewählten realen Nahverkehrsstrecken vorgenommen. Im Rahmen der durchgeführten Simulationen wird schließlich das Kraftstoffeinsparpotential in Abhängigkeit von Streckenprofil, Hybridkonfiguration und Zugart ermittelt und verglichen.
52

Dynamics and thermal behaviour of films of oriented DNA fibres investigated using neutron scattering and calorimetry techniques / Dynamique et comportement thermique des films de fibres orientées d'ADN étudiés par les techniques de diffusion de neutrons et calorimétrie

Valle Orero, Jessica 26 June 2012 (has links)
La majorité des études structurales sur l’ADN avaient été réalisées par diffraction sur des fibres tandis que ses propriétés dynamiques thermiques avaient été étudiées en solution. Lorsque la double hélice d’ADN est chauffée elle présente des séparations locales des deux brins, dont la taille augmente avec la température jusqu’à la séparation complète des brins. Ce travail étudie différents aspects de ce phénomène. Les expériences présentées dans cette thèse ont été réalisées sur des films formés de fibres orientées d’ADN préparés par la méthode du ”filage humide“. La préparation et la caractérisation des échantillons en deux formes A et B de l’ADN ont constitué une partie importante de la recherche. Une méthode pour éliminer la contamination résiduelle de la forme B dans les échantillons de forme A a été mise au point. La bonne orientation des molécules d’ADN dans les échantillons nous a permis d’étudier les fluctuations dynamiques et la transition de dénaturation thermique de l’ADN par diffraction de neutrons, sensibles à la longueur de corrélation statique le long de la molécule en fonction de la température. La transition a été étudiée pour les formes A et B pour déterminer comment elle dépend de la conformation. De plus, après la première dénaturation thermique, les films d’ADN présentent un comportement typique d’un verre. Leur relaxation thermique a été étudiée par calorimétrie. La diffusion inélastique de neutrons et de rayons X (INS et IXS) avaient été utilisées antérieurement pour mesurer les phonons longitudinaux dans des fibres d’ADN, avec des désaccords entre les résultats. Des mesures INS récentes, complétées par des simulations, avaient été cruciales pour comprendre les différentes courbes de dispersion observées. Nous avons mené des expériences INS et IXS pour poursuivre cette analyse. Des tentatives pour observer les mouvements transversaux associés à la dénaturation thermique de l’ADN, jamais observés expérimentalement, ont également été faites. / The majority of structural studies on DNA have been carried out using fibre diffraction, while studies of its dynamics and thermal behaviour have been mainly performed in solution. When the DNA double helix is heated, it exhibits local separation of the two strands that grow in size with temperature and lead to their complete separation. This work has investigated various aspects of this phenomenon. The experiments reported in this thesis were carried out on films of oriented fibres of DNA prepared with the Wet Spinning Apparatus. Thus, sample preparation and characterisation are essential parts of the research. The structures of two forms of DNA, A and B, have been explored as a function of relative humidity at fixed ionic conditions. A method to eliminate traces of ever-present B-form contamination in A-form samples was established. The high orientation of the DNA molecules within the samples allowed us to investigate dynamical fluctuations and the melting transition of DNA using neutron scattering, which can provide the spatial information crucial to understand a phase transition, probing the static correlation length along the molecule as a function of temperature. The transition has been investigated for A and B-forms in order to understand its dependence on molecular configuration.Furthermore, after the first melting, denatured DNA films show typical glass behaviour. Their thermal relaxation has been explored using calorimetry.Neutron and X-ray inelastic scattering (INS and IXS) were used in the past to measure longitudinal phonons in fibre DNA, and the results shown disagreement. Recent INS measurements supported with phonon simulations have been crucial to understand the different dispersion curves reported to date. Experiments using INS and IXS have been carried out to continue with this investigation. Attempts to observe the transverse fluctuations associated to the thermal denaturing of DNA, never experimentally investigated before, have been made.
53

Small Angle Sensing/Measurement Using 'Pattern Imaging' Method - Few Investigations

Suguna Sree, N 04 1900 (has links)
The present thesis concerns with a few investigations on sensing/measurement of small angle rotation/tilt using Pattern Imaging Method. The methodology involves looking at the tailored-objects located adjacent to the observer (CCD camera) through a mirror and extracts the angular position of the mirror from their images by processing the latter through object specific algorithm. Its principal advantage stems from the fact that small-angle measurement can be done using ambient light which is neither collimated nor filtered for single wavelength. This makes the associated optical configuration not only simple but also robust for the said application, in comparison to currently competing technologies based on Autocollimation and Interferometry. The present thesis elaborates specifically four new Pattern-Designs proposed for tailoring the spatial-brightness of the objects. Introducing for the first time, processing algorithms based on ‘Modified Fringe-Processing Strategy’ and ‘Phase-Only-Correlation’, the investigations demonstrate enhanced performance for small angle measurement with all the proposed pattern designs. The first three designs for the pattern are evaluated for 1-D measurement through fringe processing approach while the fourth pattern design is evaluated for 2-D measurement through Phase-only-Correlation. The results of the investigations are utilized to propose, design and develop a novel optical inclinometer which can work with any of the proposed pattern designs as the object. The first three pattern-designs rely upon sinusoidal modulation of the object surface and utilize three custom developed algorithms -Algorithm-A, Algorithm-B and Algorithm-C -to extract two quantities namely wrapped phase Δαw and unwrapped phase Δαuw , from the captured images. Each of these quantities will have an associated measurement range and accuracy corresponding to any of the three pattern designs. All measurements are carried out keeping the object/camera to mirror distance constant at 250 mm. From wrapped phase measurement, all the three designs, each with pitch of 2mm for sinusoidal modulation and held at a distance of 250 mm from the mirror, have been found to facilitate reliable angle measurement over a range of 850 arc seconds with accuracy better than 1 arc second after curve fitting the experimentally obtained data. From unwrapped phase measurement, the color coded as well as BCD coded composite patterns, when tested using five bands of sinusoidal modulation (with a pitch of 2mm) and held at a distance of 250 mm from the mirror, facilitated reliable angle measurement over a larger range of nearly 10 . The 2-D angle measurement using fourth pattern-design and the Algorithm-D, facilitated measurement over a range of 10 with an accuracy of 9 arc seconds when the distance between the mirror and the pattern is held at 250 mm. A comparison of the results from the present investigation with the best performance from other investigators reveals the following. The proposed modifications in the processing algorithms as well as the pattern designs help to achieve a measurement range of 750 arc seconds with accuracy better than 1 arc second from this method, with an object pattern whose lateral size is smaller by a factor of nearly 15. Such a size reduction in the object as well as the associated mirror would help to construct angle measuring instruments that work on this method more compactly. The results of the investigation have been utilized to propose and demonstrate a novel prototype optical inclinometer which has been experimentally found to work in a range of 0.40 with accuracy nearly 6 arc seconds.
54

Dynamics and thermal behaviour of films of oriented DNA fibres investigated using neutron scattering and calorimetry techniques

Valle Orero, Jessica 26 June 2012 (has links) (PDF)
The majority of structural studies on DNA have been carried out using fibre diffraction, while studies of its dynamics and thermal behaviour have been mainly performed in solution. When the DNA double helix is heated, it exhibits local separation of the two strands that grow in size with temperature and lead to their complete separation. This work has investigated various aspects of this phenomenon. The experiments reported in this thesis were carried out on films of oriented fibres of DNA prepared with the Wet Spinning Apparatus. Thus, sample preparation and characterisation are essential parts of the research. The structures of two forms of DNA, A and B, have been explored as a function of relative humidity at fixed ionic conditions. A method to eliminate traces of ever-present B-form contamination in A-form samples was established. The high orientation of the DNA molecules within the samples allowed us to investigate dynamical fluctuations and the melting transition of DNA using neutron scattering, which can provide the spatial information crucial to understand a phase transition, probing the static correlation length along the molecule as a function of temperature. The transition has been investigated for A and B-forms in order to understand its dependence on molecular configuration.Furthermore, after the first melting, denatured DNA films show typical glass behaviour. Their thermal relaxation has been explored using calorimetry.Neutron and X-ray inelastic scattering (INS and IXS) were used in the past to measure longitudinal phonons in fibre DNA, and the results shown disagreement. Recent INS measurements supported with phonon simulations have been crucial to understand the different dispersion curves reported to date. Experiments using INS and IXS have been carried out to continue with this investigation. Attempts to observe the transverse fluctuations associated to the thermal denaturing of DNA, never experimentally investigated before, have been made.
55

Development of a Variable Roller Pump and Evaluation of its Power Saving Potential as a Charge Pump in Hydrostatic Drivetrains / Development of a Variable Roller Pump and Evaluation of its Power Saving Potential as a Charge Pump in Hydrostatic Drivetrains

Zavadinka, Peter January 2015 (has links)
Predložená doktorandská dizertačná práca (ďalej len práca) sa zaoberá rozsiahlou analýzou valčekového hydrogenerátora s premenlivým geometrickým objemom a predikciou výkonových úspor dosiahnutých aplikáciou navrhnutého valčekového hydrogenerátora s premenlivým geometrickým objemom v hydrostatickom pohone vybraných mobilných pracovných strojov. Teoretický rozbor princípov fungovania valčekového hydrogenerátora a teória jednorozmerného simulačného modelu sú popísané v prvej časti práce. Na základe odvodenej teórie je vytvorený simulačný model, ktorý je vhodný na predikciu priebehu tlaku v komorách valčekového hydrogenerátora, síl pôsobiacich na valček a na predikciu vnútorných únikov vzniknutých skratovaním rozvodovej dosky, ktoré majú priamy vplyv na objemovú účinnosť valčekového hydrogenerátora. Simulačný model bol úspešne použitý pre optimalizáciu rozvodových dosiek valčekového hydrogenerátora a vhodnosť simulačného modelu potvrdili následné merania Práca obsahuje aj analýzu síl pôsobiacich na vodiaci prstenec, ktorej výsledky boli taktiež potvrdené meraním. Analýza týchto síl môže vylepšiť v konečnom dôsledku parametre budúcich tlakových regulácii. Práca ďalej obsahuje základné porovnanie použitých tlakových regulácii. Všetky uskutočnené merania potvrdili, že valčekový hydrogenerátor s premenlivým geometrickým objemom s testovanými tlakovými reguláciami je schopný úspešne pracovať v hydrostatickej prevodovke. Druhá časť práce analyzuje potenciál výkonových úspor valčekového hydrogenerátora s premenlivým geometrickým objemom pre dve mobilné aplikácie - teleskopický nakladač s hmotnosťou 9 ton a kombajn s hmotnosťou 20 ton. Analýza vyžaduje jednorozmerný simulačný model hydrostatického pohonu s teplotnou predikciou hydrostatickej prevodovky. Dva rozdielne koncepty variabilného doplňovacieho systému hydrostatickej prevodovky sú porovnané so štandardným doplňovacím systémom pre pracovný a transportný režim oboch vybraných typov vozidiel. Simulácia pohonu vozidla s valčekovým hydrogenerátorom s premenlivým geometrickým objemom vo funkcii doplňovacieho hydrogenerátora a obtokovou clonou potvrdili vyššie úspory iba v prípadoch, kedy rýchlosť doplňovacieho hydrogenerátora bola výrazne vyššia a prietok cez obtokovú clonu do skrine hlavného hydrogenerátora zabezpečil dostatočné chladenie. Najvyššie výkonové úspory boli dosiahnuté s premenlivým preplachovacím systémom, ktorého prietok sa menil podľa požiadaviek hydrostatickej prevodovky. Záver druhej časti práce sa zaoberá metodikou dimenzovania veľkosti doplňovacieho hydrogenerátora.
56

異常渦電流損を考慮したモータの鉄損予測手法に関する研究 / イジョウ ウズデンリュウソン オ コウリョ シタ モータ ノ テッソン ヨソク シュホウ ニカンスル ケンキュウ

吉岡 卓哉, Takuya Yoshioka 22 March 2020 (has links)
近年、自動車の電動化が加速しており、車両駆動を担うモータのさらなる効率向上が求められている。高効率モータ設計に向けて、主な損失の1つである鉄損予測の精度向上が求められている。本論文では、鉄損を構成する各種損失の中から、実用的なモデル化手法が確立していない、異常渦電流損に関して、磁気測定から影響を与える諸因子を検討した。また、得られた知見に基づき、モータ鉄損予測にあたり、実用的なモデルを開発した。 / In recent years, electrification of automobiles has accelerated, and further improvement in efficiency of motors that drive the vehicles is required. For high-efficiency motor design, it is important to improve the accuracy of iron loss estimation, which is one of the main losses in the motor. In this paper, we investigated influencing factors of excess loss, which is one element that consists iron loss and has not been established as practical estimating modeling, from the magnetic measurement. In addition, based on the obtained knowledge, a practical model was developed for motor iron loss estimation. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University

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