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Li, Quan. "Integrated motions of light driven molecular motors at macroscopic scale". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF001/document.
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Dans la nature, des moteurs moléculaires tells que l'ATP synthase ou la kinésine peuvent consommer de l'énergie pour générer du mouvement et ainsi assurer des fonctions essentielles comme le transport ou la synthèse de molécules. La préparation de moteurs artificiels capables de fournir un travail à différentes échelles est un défi important pour les chimistes. Dans ce travail, nous avons conçu et synthétisé de manière stéréosélective un moteur moléculaire unidirectionnel et hautement fonctionnalisé à l'échelle du gramme. La fonctionnalisation orthogonale du moteur permet de l'intégrer dans des matériaux polymères. Grâce à une réaction de "click" réalisée sous différentes conditions de dilution, nous avons pu obtenir soit une macromolécule bicyclique en forme de 8 soit un gel de polymers dont les moteurs constituent les points de réticulation. Sous irradiation UV, les moteurs tournent ce qui enroule les chaines de polymers. Pour le bicycle, la taille caractéristique de la macromolécule diminue tandis que la morphologie évolue vers une pelote étirée. Dans le cas du gel, suite à la rotation des moteurs, l'enroulement des chaines conduit à une contraction du gel de l'ordre de 80% en volume. C'est le premier exemple d'intégration de mouvements moléculaires hors équilibre résultant en une réponse observable à l'échelle macroscopique. Ce travail ouvre des perspectives intéressantes dans le domaine des nanotechnologies ainsi que dans celui de l'énergieNatural molecular motors such as ATP synthase, myosin, kinesin and dynein can convert conformationalchanges, due to chemical energy input, into directed motion for catalysis and transport. Preparing artificial molecular motors and making them work at different scales (from nano to macroscopic scale) have been long-term challenges. Herein we designed and synthesized a light driven rotary molecular motor in highly enantiopure form and in gram scale. This motor is featured by two orthogonal functionalities on its upper and lower part, allowing its further integration into polymeric materials. By performing click reaction under different concentration conditions, either an eight shaped motor-polymer conjugate or a gel containing motors as reticulation units could be obtained. Upon UV irradiation, the polymer chains could be entangled due to the rotation of this motor. For eight shaped polymer, the dimension was changed towards smaller dimension, and the morphology was changed from cycle to collapsed coils (spherical or more elongated). For the gel, due to the twisting of polymer chains induced by the rotation of the motor, it could be contracted significantly (80 %) compared with its original volume. The integration of machines which display motions out of equilibrium at nanoscale to movement in the macroscopic world which is extensively used in natural systems will open very interesting prospects in nanotechnology for further developments
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Mendoza, Sandra Marina. "Exploiting molecular machines on surfaces". [S.l. : Groningen : s.n. ; University Library Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/304755133.
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Sasai, Masaki, Tomoki P. Terada y Mitsunori Takano. "Unidirectional Brownian motion observed in an in silico single molecule experiment of an actomyosin motor". National Academy of Sciences, 2010. http://hdl.handle.net/2237/20619.
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Goujon, Antoine. "Macroscopic amplification of nanoscopic motions induced by molecular machines". Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF044/document.
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Ces vingt dernières années, le domaine du design et de la synthèse de machines moléculaires complexes a fait d’énormes progrès,souvent inspiré par la beauté de la machinerie présente dans les systèmes vivants. Cependant, l’amplification des mouvements d’un grand nombre de machines moléculaires à des échelles de tailles largement supérieures à leurs dimensions restent un défi théorique et expérimental ambitieux et ardu. Ce travail décrit comment l’organisation de machines et moteurs moléculaires dans des réseaux polymères supramoléculaires ou covalents permet de synthétiser des matériaux dans lesquels leurs mouvements individuels nanométriques sont amplifiés jusqu’à l’échelle macroscopique. Les trois premiers chapitres décrivent l’utilisation d’une architecture de type [c2]daisy chains, une molécule capable d’effectuer des contraction/extensions similaires aux mouvements des sarcomères présents dans les muscles, dans des réseaux polymères supramoléculaires et covalents. Leur introduction dans des polymères supramoléculaires à liaisons hydrogène basées sur le motif de reconnaissance uracil:2,6-diacetylaminopyridine associé à des interactions latérales tel que les interactions π résulta en la formation de fibre supramoléculaires contractiles dont la taille et la morphologie a pu être commuté entre deux états étendus et contractés. L’incorporation de motifs uréidopyrimidinone comme connecteur supramoléculaire en revanche donna accès à des gels supramoléculaires, évoluant vers un état liquide lors de la contraction des chaines polymères. Finalement, l’inclusion de daisy chains dans un réseau polymère 3D a donné accès à un gel chimique. Ce matériau a pu être contracté et étendu à l’échelle macroscopique grâce à l’action combinée des machines moléculaires le constituant.Le quatrième chapitre est dédié à l’amélioration d’un gel contractile basé sur l’utilisation de moteurs moléculaires rotatif comme noeud de réticulation d’un réseau polymère. Une unité modulatrice, capable d’être commuté entre un état “ouvert” et “fermé”, a été introduite dans le réseau aux côtés du moteur. Le modulateur dans son état “fermé” permet aux moteurs moléculaires de contracter efficacement le réseau, tandis que dans son état ouvert il permet aux chaines de se dérouler alors que le moteur ne tourne pas, ce qui provoque l’extension du réseau qui retourne à sa taille initiale. En résumé, le travail décrit dans ce manuscrit illustre que des machines moléculaires soigneusement conçue peuvent être introduites dans des réseaux polymères, fournissant des matériaux dont les propriétés macroscopiques sont affectées par les mouvements nanoscopiques de ses constituants. Ces résultats fournissent des pistes et une base fondamentale pour l’élaboration d’une nouvelle classe de matériaux contractiles basés sur des machines moléculairesThe last twenty years have seen tremendous progresses in the design and synthesis of complex molecular machines, often inspired by the beauty of the machinery found in biological systems. However, amplification of the molecular machines motion over several orders of magnitude above their typical length scale is still an ambitious challenge. This work describes how self-organization of molecular machines or motors allows for the synthesis of materials translating the motions of their components into a macroscopic response. The three first chapters describe the use of a [c2]daisy chains architecture, a molecule able to perform contraction/extension motions similarly to the sarcomere units of muscles, into systems such as supramolecular polymers and covalent networks. Their inclusion into hydrogen bonding supramolecular polymers based on the uracil:2,6-diacetylaminopyridine recognition motifs combined with lateral interactions such as π-stacking provided micrometric muscle-like fibers contracting and extending upon deprotonation and protonation.The incorporation of ureidopyrimidone moieties as supramolecular connectors yielded highly organized gels, which evolved to a liquidstate upon contraction of the polymer chains. Finally, covalent poly[c2]daisy chains were synthesized and investigated, notably the formation of a 3D network swelling into a gel. This material could contract and extend at the macroscopic scale upon contraction and extension of the molecular machines used as monomers. Finally, a fourth chapter is dedicated to the improvement of contractile chemical gels made by using a molecular motor as reticulating nodes. A modulating unit, able to be switched between a “closed” and an “opened” state, was introduced into the polymer network along with the motor. The locked structure in the “closed” state allowed contraction of the gel upon rotation of the molecular motors, while the “opened” state allowed unwinding of the entangled polymer chains and extension of the gel when the motor is off. Overall, the work presented in this manuscript demonstrates that carefully designed molecular machines can be incorporated into large supramolecular or covalent assemblies, providing materials which collective motions alter their macroscopic properties. These results provide valuable insights for the elaboration of a new class of muscle-like materials based on molecular machines
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Cherraben, Sawsen. "Machines moléculaires à base de cyclodextrines fonctionnalisées". Thesis, Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2019SORUS633.pdf.
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Le contrôle du mouvement et de sa directionnalité à l’échelle moléculaire est un défi actuel. Ce travail de thèse s’est intéressé à l’élaboration d’une famille de machines moléculaires à base de cyclodextrines (CDs). L’objectif a été d’exploiter l’asymétrie intrinsèque des CDs et de les fonctionnaliser sélectivement afin de pouvoir leur appliquer directement un stimulus. Nous pouvons dès lors contrôler leurs mouvements dans des architectures supramoléculaires. Dans une première approche, nous avons développé un commutateur pH-sensible de type pseudo-rotaxane à base de CDs sélectivement fonctionnalisées par des amines sur le col primaire. Un contrôle de l’enfilage et du désenfilage par un stimulus pH et une modulation de la cinétique de désenfilage par variation du nombre d’amines ont été obtenus. Dans une deuxième approche, nous avons conçu un système utilisant un carburant chimique pour obtenir un mouvement unidirectionnel par le transport actif d’une CD fonctionnalisée. Le point clé est l’étape de clivage de groupements protecteurs sur l’axe par la fonction catalytique portée par la CD, qui devrait avoir lieu préférentiellement par le col primaire et assurer son transport dirigé. Pour cela, un premier [2]rotaxane modèle de CDMe à trois stations a été synthétisé par une approche de post-fonctionnalisation d’un [2]rotaxane, avec des bouchons amides. Son étude a montré la formation de 3 mécano-isomères lors de la réaction de protection avec une distribution non-statistique indiquant un probable biais cinétique. Ces travaux prometteurs ouvrent des perspectives à plus long terme sur l’obtention de moteurs moléculaires à énergie chimique avec un transport actif de la CDControlling motion and directionality at the molecular level is a major challenge. This thesis project focused on the development of a family of cyclodextrin (CDs) based molecular machines. The objective was to exploit the inherent asymmetry of CDs and to functionalize them selectively in order to be able to apply a stimulus directly to them. Hence, controlling their movements in supramolecular architectures becomes possible. In the first approach, we developed a pH-sensitive switch of the pseudo-rotaxane type based on CDs selectively functionalized by amines on the primary rim. A remarkable control of threading and dethreading by a pH stimulus were obtained, along with a modulation of the dethreading kinetics by variation in the number of amines. In a second approach, we designed a system using a chemical fuel to obtain unidirectional motion of a functionalized CD through its active transport. The key step is the cleavage of protective groups located on the axis by the catalytic function carried by the CD, which should preferably take place through the primary rim, ensuring its directed transport. For this purpose, a first three-station [2]rotaxane CDMe model was synthesized by a post-functionalization approach of a one-station [2]rotaxane with amide stoppers. Its study showed the formation of 3 mechano-isomers during the protective reaction with a non-statistical distribution indicating a probable kinetic bias. This promising work opens up longer-term perspectives on the development of chemically fueled molecular motors with active CD transport
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Sirven, Agnès. "Nano-machines : vers la synthèse d'un treuil moléculaire". Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30200.
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Dans le domaine des nanomachines, des progrès considérables ont été réalisés. Il est désormais possible de synthétiser une machine moléculaire et de contrôler son mouvement grâce à une source d'énergie chimique, lumineuse ou électrique, de façon à ce qu'il soit unidirectionnel. Un nouveau défi a surgi : comment rendre ce mouvement utile ? Comment utiliser le travail d'une machine moléculaire au niveau nanoscopique, mésoscopique ou macroscopique ? Cette thèse s'inscrit à la suite de la démonstration du contrôle de la rotation d'un moteur moléculaire. Ce moteur est un complexe de ruthénium(II) dont la rotation de la partie mobile, le rotor, est contrôlée par la pointe d'un microscope à effet tunnel. Afin de déterminer le travail limite fournit par ce moteur, nous avons synthétisé un nanotreuil intégrant le moteur moléculaire déjà étudié dans l'équipe avec une chaîne latérale permettant d'accrocher par chimie clic différents types de fragments moléculaires. Ces fragments ayant des natures chimiques différentes (fullerènes, triptycènes, porphyrines), ils interagiront de manière plus ou moins importante avec la surface. De ce fait, la rotation du moteur pourra ou ne pourra pas entraîner leur déplacement sur la surface, ce qui nous permettra d'estimer le travail du moteur. Cette thèse décrit la synthèse des différentes sous-unités de ce nanotreuil : le moteur dissymétrique, la chaîne et les différentes charges. Après avoir développé différentes stratégies visant à intégrer la chaîne sur le rotor, la synthèse de chacun des fragments moléculaires fera l'objet des chapitres suivants. Enfin, un chapitre mettra en perspective l'intégration possible du moteur dans des systèmes d'engrenages en vue de la récupération du travail dans un réseau supramoléculaireIn the field of molecular machines, considerable developments have been achieved. Nowadays, it is possible to synthesize a molecular machine with a directional control on its motion thanks to chemical, light or electrical energy source. A new challenge has arised: how make that movement useful ? How use the work of a molecular machine at a nano-, meso- or macro-level ? This thesis is in line with the demonstration and control of the molecular motor rotation. This motor consists in a ruthenium(II) complexe whom rotation of the movable part, i.e. the rotor, is controlled by the scanning tunnelling microscope tip. In order to estimate its motive power, we have synthesized a nanowinch incorporating the molecular motor synthesized in the team. This motor has been desymmetrized to be able to incorporate a chain allowing to connect by click chemistry several kind of molecular fragments. These fragments (fullerenes, triptycenes, porphyrines) will interact more or less with the surface of deposition. Therefore, the motor rotation will or will not make them move on the surface, giving us the possibility to estimate the motor torque. In this thesis, the synthesis of the different parts of the nanowinch is described : the dissymmetric molecular motor, the linker and the loads. After developping the synthetic strategies allowing us to incorporate the linker on the rotor, the synthesis of each fragment will be detailled in the following chapters. A concluding chapter will deal with the possible integration of that type of complexes into molecular gears in order to exploit the torque in a supramolecular network
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Daou, Dania. "Intégration de moteurs moléculaires photoactivables dans des gels supramoléculaires". Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAF021.
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Cette thèse a exploré l'intégration de moteurs moléculaires synthétiques photoactivables dans des réseaux de gels supramoléculaires. L'objectif principal était d'obtenir un mouvement macroscopique réversible en exploitant à la fois la rotation unidirectionnelle des moteurs moléculaires et la nature réversible des interactions supramoléculaires. Des moteurs moléculaires hautement fonctionnalisés ont été synthétisés et intégrés comme unités de réticulation dans des réseaux de gel supramoléculaire de peptides de diphénylalanine et de poly(γ-benzyl-L-glutamate) et d'oligonucléotides d'ADN. L'activation de la rotation unidirectionnelle des moteurs moléculaires par la lumière a permis de produire un travail nanomécanique suffisant pour perturber les interactions supramoléculaires dans les réseaux de gel à base de peptides, ce qui entraîne la contraction ou la fonte du gel à l'échelle macroscopique. Grâce aux interactions supramoléculaires réversibles, le matériau gélifié initial a pu être récupéré dans l'obscurité, soit spontanément, soit par l'application d'un stimulus thermique. Les systèmes étudiés dans cette thèse représentent une nouvelle classe de matériaux fonctionnant dans des conditions dissipatives hors équilibre, promettant des applications dans divers domaines tels que la biologie, la médecine et la science des matériauxThis thesis explored the integration of light-driven synthetic molecular motors in supramolecular gel networks. The main goal was to achieve reversible macroscopic motion by exploiting both the unidirectional rotation of molecular motors and the reversible nature of supramolecular interactions. Highly functionalized molecular motors have been synthesized and integrated as crosslinking units in supramolecular gel networks of diphenylalanine and poly(γ- benzyl-L-glutamate) peptides, as well as DNA oligonucleotides. Activation of the unidirectional rotation of molecular motors by light, allowed the production of nanomechanical work which is sufficient to disrupt supramolecular interactions in peptide-based gel networks leading to contraction or melting of the gel material at the macroscopic scale. Thanks to the reversible supramolecular interactions, the initial gel material was recovered in the dark, either spontaneously or by applying a thermal stimulus. The systems studied in this thesis represent a novel class of materials operating in dissipative out-of-equilibrium conditions, holding promise of applications in various fields such as biology, medicine and material science
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Cox, Thomas. "Development of novel linear drive machines". Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500760.
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Linear induction machines currently play a relatively minor role in the industrial world. This is partly due to relatively high production costs, complexity of construction and the Inability to apply standard mass production techniques. The aim of this thesis is to investigate the design of linear machines that are cheaper and faster to produce, and that may easily be mass-produced This thesis principally concerns the use of concentrated winding linear stators. These are cheap and easy to manufacture and can be easily mass-produced. However, high levels of negative harmonics make them unsuitable for use with simple sheet rotors.
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Göl, Özdemir. "Dynamic modelling of induction machines /". Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phg595.pdf.
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Hanekom, Alwyn Nicolaas. "A torque ripple analysis on reluctance synchronous machines". Thesis, Cape Peninsula University of Technology, 2006. http://hdl.handle.net/20.500.11838/1145.
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Thesis MTech(Electrical Engineering))--Cape Peninsula University of Technology, 2006Reluctance Synchronous Machines (RSM) have, due to their rotor geometry, an inherently high torque ripple. This torque ripple is defined as the deviation of the minimum and maximum torque from the average value. It is unwanted as it indicates uneven pull on the rotor causing deformation of it and hence different air-gaps along the rotor circumference as well as acoustic noise. In applications such as power steering, robotics and radar positioning systems where high precision movement is vital, oscillating torque will lead to the malfunction of these devices and therefore suppressed the use and development of RSMs. Unlike the Induction machine (IM), the RSM has no copper losses in the rotor, which reduces the operating temperature significantly. With the development of electronic drives the quality of the output torque could be improved by means of accurate current- and flux space phasor control methods with much success and made the RSM a possible replacement for the IM. However, reducing torque ripple by means of purely geometrical changes is still a challenge to the machine designer. This thesis will focus on the reduction of torque ripple while leaving the average torque relatively unchanged by changing the rotor geometry. The rotor changes will take place by means of flux barriers and cut-outs while the stator has either semi-closed slots or magnetic wedges. In this work rotor structures with equal harmonic magnitudes but their angles 1800 apart. will be combined to form one machine and identify how torque harmonics respond. The change in average torque and power factor will be evaluated with all geometrical changes made to these machines throughout this work.
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Bradshaw, William Kenneth. "Control of hybrid machines". Thesis, Liverpool John Moores University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363174.
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Li, Zhou, of Western Sydney Nepean University y of Mechatronic Computer and Electrical Engineering School. "Numerical computation of core losses in permanent magnet machines". THESIS_XXXX_MCEE_Li_Z.xml, 2000. http://handle.uws.edu.au:8081/1959.7/284.
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This thesis presents a study on core loss calculations in rotating electrical machines. The basic concepts concerning magnetic moments, ferromagnetism, magnetic domains and magnetic hysteresis are introduced. The three-term models for alternating and rotational core losses in electrical steel sheets are presented. Several core loss measurement techniques are reviewed and an experiment is carried out to measure the total core losses in an electrical sheet steel sample under alternating and rotational magnetic fields of various frequencies and amplitudes. The coefficients in the loss models for alternating and rotational core losses are obtained through curve fitting process. The theory of electromagnetic fields is presented through the Maxwell equations and field scalar equations. A detailed review on core loss models for rotating electrical machines is presented. A rotational core loss model is adopted to calculate the core losses in a PM motor. The total core loss in the PM motor is obtained by summing the element losses using a MATLAB program. An experiment is conducted to measure the total core loss in the PM motor. The calculated total core loss in the PM motor is compared with the experimental results. The calculated total core losses are about 19% lower than the tested results. Various possible causes for this discrepancy are discussedMaster of Engineering (Hons)
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Liu, Chunhua. "Design, analysis, control and application of permanent-magnet hybrid brushless machines". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841665.
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Niu, Shuangxia. "Design, control and application of double-stator permanent magnet brushless machines". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841677.
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Vilfan, Andrej. "Collective dynamics of molecular motors". [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=959980024.
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Jaster, Nicole. "Ratchet models of molecular motors". Phd thesis, Universität Potsdam, 2003. http://opus.kobv.de/ubp/volltexte/2005/90/.
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Transportvorgänge in und von Zellen sind von herausragender Bedeutung für das Überleben des Organismus. Muskeln müssen sich kontrahieren können, Chromosomen während der Mitose an entgegengesetzte Enden der Zelle bewegt und Organellen, das sind von Membranen umschlossene Kompartimente, entlang molekularer Schienen transportiert werden. Molekulare Motoren sind Proteine, deren Hauptaufgabe es ist, andere Moleküle zu bewegen. Dazu wandeln sie die bei der ATP-Hydrolyse freiwerdende chemische Energie in mechanische Arbeit um. Die Motoren des Zellskeletts gehören zu den drei Superfamilien Myosin, Kinesin und Dynein. Ihre Schienen sind Filamente des Zellskeletts, Actin und die Microtubuli.
In dieser Arbeit werden stochastische Modelle untersucht, welche dazu dienen, die Fortbewegung dieser linearen molekularen Motoren zu beschreiben. Die Skala, auf der wir die Bewegung betrachten, reicht von einzelnen Schritten eines Motorproteins bis in den Bereich der gerichteten Bewegung entlang eines Filaments. Ein Einzelschritt überbrückt je nach Protein etwa 10 nm und wird in ungefähr 10 ms zurückgelegt. Unsere Modelle umfassen M Zustände oder Konformationen, die der Motor annehmen kann, während er sich entlang einer eindimensionalen Schiene bewegt. An K Orten dieser Schiene sind Übergänge zwischen den Zuständen möglich. Die Geschwindigkeit des Proteins lässt sich in Abhängigkeit von den vertikalen Übergangsraten zwischen den einzelnen Zuständen analytisch bestimmen. Wir berechnen diese Geschwindigkeit für Systeme mit bis zu vier Zuständen und Orten und können weiterhin eine Reihe von Regeln ableiten, die uns einschätzen helfen, wie sich ein beliebiges vorgegebenes System verhalten wird.
Darüber hinaus betrachten wir entkoppelte Subsysteme, also einen oder mehrere Zustände, die keine Verbindung zum übrigen System haben. Mit einer bestimmten Wahrscheinlichkeit kann ein Motor einen Zyklus von Konformationen durchlaufen, mit einer anderen Wahrscheinlichkeit einen davon unabhängigen anderen.
Aktive Elemente werden in realen Transportvorgängen durch Motorproteine nicht auf die Übergänge zwischen den Zuständen beschränkt sein. In verzerrten Netzwerken oder ausgehend von der diskreten Mastergleichung des Systems können auch horizontale Raten spezifiziert werden und müssen weiterhin nicht mehr die Bedingungen der detaillierten Balance erfüllen. Damit ergeben sich eindeutige, komplette Pfade durch das jeweilige Netzwerk und Regeln für die Abhängigkeit des Gesamtstroms von allen Raten des Systems. Außerdem betrachten wir die zeitliche Entwicklung für vorgegebene Anfangsverteilungen.
Bei Enzymreaktionen gibt es die Idee des Hauptpfades, dem diese bevorzugt folgen. Wir bestimmen optimale Pfade und den maximalen Fluss durch vorgegebene Netzwerke.
Um darüber hinaus die Geschwindigkeit des Motors in Abhängigkeit von seinem Treibstoff ATP angeben zu können, betrachten wir mögliche Reaktionskinetiken, die den Zusammenhang zwischen den unbalancierten Übergangsraten und der ATP-Konzentration bestimmen. Je nach Typ der Reaktionskinetik und Anzahl unbalancierter Raten ergeben sich qualitativ unterschiedliche Verläufe der Geschwindigkeitskurven in Abhängigkeit von der ATP-Konzentration.
Die molekularen Wechselwirkungspotentiale, die der Motor entlang seiner Schiene erfährt, sind unbekannt.Wir vergleichen unterschiedliche einfache Potentiale und die Auswirkungen auf die Transportkoeffizienten, die sich durch die Lokalisation der vertikalen Übergänge im Netzwerkmodell im Vergleich zu anderen Ansätzen ergeben.
Transport processes in and of cells are of major importance for the survival of the organism. Muscles have to be able to contract, chromosomes have to be moved to opposing ends of the cell during mitosis, and organelles, which are compartments enclosed by membranes, have to be transported along molecular tracks.
Molecular motors are proteins whose main task is moving other molecules.For that purpose they transform the chemical energy released in the hydrolysis of ATP into mechanical work. The motors of the cytoskeleton belong to the three super families myosin, kinesin and dynein. Their tracks are filaments of the cytoskeleton, namely actin and the microtubuli.
Here, we examine stochastic models which are used for describing the movements of these linear molecular motors. The scale of the movements comprises the regime of single steps of a motor protein up to the directed walk along a filament. A single step bridges around 10 nm, depending on the protein, and takes about 10 ms, if there is enough ATP available. Our models comprise M states or conformations the motor can attain during its movement along a one-dimensional track. At K locations along the track transitions between the states are possible. The velocity of the protein depending on the transition rates between the single states can be determined analytically. We calculate this velocity for systems of up to four states and locations and are able to derive a number of rules which are helpful in estimating the behaviour of an arbitrary given system.
Beyond that we have a look at decoupled subsystems, i.e., one or a couple of states which have no connection to the remaining system. With a certain probability a motor undergoes a cycle of conformational changes, with another probability an independent other cycle.
Active elements in real transport processes by molecular motors will not be limited to the transitions between the states. In distorted networks or starting from the discrete Master equation of the system, it is possible to specify horizontal rates, too, which furthermore no longer have to fulfill the conditions of detailed balance. Doing so, we obtain unique, complete paths through the respective network and rules for the dependence of the total current on all the rates of the system. Besides, we view the time evolutions for given initial distributions.
In enzymatic reactions there is the idea of a main pathway these reactions follow preferably. We determine optimal paths and the maximal flow for given networks.
In order to specify the dependence of the motor's velocity on its fuel ATP, we have a look at possible reaction kinetics determining the connection between unbalanced transitions rates and ATP-concentration. Depending on the type of reaction kinetics and the number of unbalanced rates, we obtain qualitatively different curves connecting the velocity to the ATP-concentration.
The molecular interaction potentials the motor experiences on its way along its track are unknown. We compare different simple potentials and the effects the localization of the vertical rates in the network model has on the transport coefficients in comparison to other models.
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Müller, Melanie J. I. "Bidirectional transport by molecular motors". Phd thesis, Universität Potsdam, 2008. http://opus.kobv.de/ubp/volltexte/2008/1871/.
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In biological cells, the long-range intracellular traffic is powered by molecular motors which transport various cargos along microtubule filaments. The microtubules possess an intrinsic direction, having a 'plus' and a 'minus' end. Some molecular motors such as cytoplasmic dynein walk to the minus end, while others such as conventional kinesin walk to the plus end. Cells typically have an isopolar microtubule network. This is most pronounced in neuronal axons or fungal hyphae. In these long and thin tubular protrusions, the microtubules are arranged parallel to the tube axis with the minus ends pointing to the cell body and the plus ends pointing to the tip.
In such a tubular compartment, transport by only one motor type leads to 'motor traffic jams'. Kinesin-driven cargos accumulate at the tip, while dynein-driven cargos accumulate near the cell body. We identify the relevant length scales and characterize the jamming behaviour in these tube geometries by using both Monte Carlo simulations and analytical calculations.
A possible solution to this jamming problem is to transport cargos with a team of plus and a team of minus motors simultaneously, so that they can travel bidirectionally, as observed in cells. The presumably simplest mechanism for such bidirectional transport is provided by a 'tug-of-war' between the two motor teams which is governed by mechanical motor interactions only. We develop a stochastic tug-of-war model and study it with numerical and analytical calculations. We find a surprisingly complex cooperative motility behaviour. We compare our results to the available experimental data, which we reproduce qualitatively and quantitatively.In biologischen Zellen transportieren molekulare Motoren verschiedenste Frachtteilchen entlang von Mikrotubuli-Filamenten. Die Mikrotubuli-Filamente besitzen eine intrinsische Richtung: sie haben ein "Plus-" und ein "Minus-"Ende. Einige molekulare Motoren wie Dynein laufen zum Minus-Ende, während andere wie Kinesin zum Plus-Ende laufen. Zellen haben typischerweise ein isopolares Mikrotubuli-Netzwerk. Dies ist besonders ausgeprägt in neuronalen Axonen oder Pilz-Hyphen. In diesen langen röhrenförmigen Ausstülpungen liegen die Mikrotubuli parallel zur Achse mit dem Minus-Ende zum Zellkörper und dem Plus-Ende zur Zellspitze gerichtet. In einer solchen Röhre führt Transport durch nur einen Motor-Typ zu "Motor-Staus". Kinesin-getriebene Frachten akkumulieren an der Spitze, während Dynein-getriebene Frachten am Zellkörper akkumulieren. Wir identifizieren die relevanten Längenskalen und charakterisieren das Stauverhalten in diesen Röhrengeometrien mit Hilfe von Monte-Carlo-Simulationen und analytischen Rechnungen. Eine mögliche Lösung für das Stauproblem ist der Transport mit einem Team von Plus- und einem Team von Minus-Motoren gleichzeitig, so dass die Fracht sich in beide Richtungen bewegen kann. Dies wird in Zellen tatsächlich beobachtet. Der einfachste Mechanismus für solchen bidirektionalen Transport ist ein "Tauziehen" zwischen den beiden Motor-Teams, das nur mit mechanischer Interaktion funktioniert. Wir entwickeln ein stochastisches Tauzieh-Modell, das wir mit numerischen und analytischen Rechnungen untersuchen. Es ergibt sich ein erstaunlich komplexes Motilitätsverhalten. Wir vergleichen unsere Resultate mit den vorhandenen experimentellen Daten, die wir qualitativ und quantitativ reproduzieren.
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Qi, Fei. "Light-driven molecular rotary motors". HKBU Institutional Repository, 2017. https://repository.hkbu.edu.hk/etd_oa/434.
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In the past two decades, a number of artificial molecular motors have been constructed using organic molecules as components which can perform unidirectional motion. Among the best-known examples are the light-activated molecular rotary motors synthesized and analyzed in B. L. Feringa's lab. Yet there is limited understanding of the photoisomerization and thermal isomerization processes that control the speed and energy conversion efficiency of these molecular devices. The present thesis work aims at: 1) developing a computational methodology to provide the atomic and electronic details that allow for quantitative descriptions of light-activated molecular motion, 2) improving the understanding of the physical principles governing photo- and thermal-isomerization processes in specific molecular systems, and 3) proposing a new strategy of molecule design to assist experimental investigations. A key component in our methodology is the calculation of the potential energy surface (PES) spanned by collective atomic coordinates using ab initio quantum mechanical methods. This is done both for the electronic ground state, which is relatively straightforward, and for the photo-excited state, which is more involved. Once the PES is known, classical statistical mechanical methods can be used to analyze the dynamics of the slow variables from which information about the rotational motion can be extracted. Calculation of the PES is computationally expensive if one were to sample the very high dimensional space of the atomic coordinates. A new method, based on the torque experienced by individual atoms, is developed to capture key aspects of the intramolecular relaxation in terms of angular variables associated with the rotational degrees of freedom. The effectiveness of the approach is tested on specific light-driven molecular rotary motors that were successfully synthesized and analyzed in previous experiments. Finally, based on the experience accumulated in this study, a new molecular rotary motor driven by visible light is proposed to reach MHz rotational frequency.
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Keller, Peter. "Mathematical modeling of molecular motors". Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2013/6304/.
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Amongst the many complex processes taking place in living cells, transport of cargoes across the cytosceleton is fundamental to cell viability and activity. To move cargoes between the different cell parts, cells employ Molecular Motors. The motors operate by transporting cargoes along the so-called cellular micro-tubules, namely rope-like structures that connect, for instance,
the cell-nucleus and outer membrane. We introduce a new Markov Chain, the killed Quasi-Random-Walk, for such transport molecules and derive properties like the maximal run length and time. Furthermore we introduce permuted balance, which is a more flexible extension of the ordinary reversibility and introduce the notion of Time Duality, which compares certain passage times pathwise. We give a number of sufficient conditions for Time Duality based on the geometry of the transition graph. Both notions are closely related to properties of the killed Quasi-Random-Walk.
20
Neetz, Manuel. "Collective behavior of molecular motors". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-85935.
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Microtubule associated molecular motors are involved in a multitude of fundamental cellular processes such as intracellular transport and spindle positioning. During these movements multiple motor proteins often work together and are, therefore, able to exert high forces. Thus force generation and sensing are common mechanisms for controlling motor driven movement. These mechanisms play a pivotal role when motor proteins antagonize each other, e.g. to facilitate oscillations of the spindle or the nucleus.
Single motor proteins have been characterized in depth over the last two decades, our understanding of the collective behavior of molecular motors remains, however, poor. Since motor proteins often cooperate while they walk along microtubules, it is necessary to describe their collective reaction to a load quantitatively in order to understand the mechanism of many motor-driven processes.
I studied the antagonistic action of many molecular motors (of one kind) in a gliding geometry. For this purpose I crosslinked two microtubules in an antiparallel fashion, so that they formed \"doublets\". Then I observed the gliding motility of these antiparallel doublets and analyzed the gliding velocity with respect to the relative number of motors pulling or pushing against each other. I observed that the antiparallel doublets gliding on conventional kinesin-1 (from Drosophila melanogaster) as well as cytoplasmic dynein (from Saccharomyces cerevisae) exhibited two distinct modes of movement, slow and fast, which were well separated. Furthermore I found a bistability, meaning, that both kinds of movement, slow and fast, occurred at the same ratio of antagonizing motors. Antiparallel doublets gliding on the non-processive motor protein Ncd (the kinesin-14 from D. melanogaster) showed, however, no bistability. The collective dynamics of all three motor proteins were described with a quantitative theory based on single-motor properties.
Furthermore the response of multiple dynein motors towards an external, well-defined load was measured in a gliding geometry by magnetic tweezing. Examples of multi-motor force-velocity relationships are presented and discussed. I established, furthermore, a method for counting single surface immobilized motors to guide the evaluation of the tweezing experiments.
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Parsa, Leila. "Performance improvement of permanent magnet ac motors". Texas A&M University, 2005. http://hdl.handle.net/1969.1/2419.
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Multi-phase motors have several advantages over the traditional three-phase motors.
In this study, the additional degrees of freedom available in five-phase permanent
magnet motors have been used for three purposes: 1) enhancing the torque producing
capability of the motor, 2) improving the reliability of the system, and 3) better adjusting
of the torque and flux linkages of the five-phase direct torque controlled system.
1) Due to the fact that space and time harmonics of the same orders will contribute
positively to output torque, a five-phase permanent magnet motor with quasi-rectangular
back-EMF waveform is supplied with combined fundamental and third harmonic of
currents. For modeling and analysis of the motor a 0 3 3 1 1 q d q d frame of reference is
defined where 1 1q d rotates at the synchronous speed and 3 3q d rotates at the three times
synchronous speed. Based on the mathematical model in the 0 3 3 1 1 q d q d frame of
reference, it is shown that this system while having a higher torque density with respect
to a conventional permanent magnet synchronous machine, is also compatible with
vector control algorithm.
2) A resilient current control of the five-phase permanent motor with both sinusoidal
and trapezoidal back-EMF waveforms under asymmetrical fault condition is proposed.
In this scheme, the stator MMF is kept unchanged during healthy and faulty condition.
Therefore, the five-phase permanent magnet motor operates continuously and steadily
without additional hardware and just by modifying the control algorithm in case of loss
of up to two phases. The feature is of major importance in some specific applications
where high reliability is required.
3) High torque and flux ripple are the major drawbacks of a three-phase direct
torque controlled system. The number of space voltage vectors directly influences the
performance of DTC system. A five-phase drive, while benefiting from other advantages
of high order phase drives, has inherently 32 space voltage vectors which permits better
flexibility in selecting the switching states and finer adjustment of flux and torque. A
sensorless direct torque control of five-phase permanent magnet motor is implemented.
Speed information is obtained based on the position of stator flux linkages and load
angle.
Experiments have been conducted on a 5kW five-phase surface mount permanent
magnet motor and a 3kW five-phase interior permanent magnet motor by using
TMS320C32 DSP. The results obtained are consistent with theoretical studies and
simulation analysis, which further demonstrate the feasibility and practical significance
of the five-phase permanent magnet motor drives.
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Li, Jiangui y 李建贵. "Design, analysis and control of permanent-magnet vernier machines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49617655.
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Electric machines are indispensable part in modern industry and they are widely used in many applications such as power generation, vehicles, elevator, robot, and so on. Owing to the diversity of the application occasions, different requirements have been proposed. In the applications, such as wind power generation, low-speed, high-torque and high-efficiency electric machines are required to match with the low-speed load. Currently, this problem is handled by either adopting a speed-boost mechanical gear, or using low-speed machine design. The former one causes mechanical wear and tear, audible noise and low efficiency, whereas the latter one increases the generator size and weight as well as raw material cost.
In recent years, another option, namely integrating a coaxial magnetic gear into a permanent-magnet (PM) machine has been proposed. This option allows for directly mounting the outer, low-speed shaft with the load while enables the electric machine coupled with the high-speed inner gear to operate at high speeds. However, this magnetic-geared electric machine desires a complex structure, involving two rotating bodies and three air-gaps, which increases manufacture difficulty and cost. The research work of this thesis attempts to solve the speed-matching problem by developing a new electric machine.
The incorporation of vernier concept with PM machine gives birth to the permanent-magnet verier (PMV) machine. Different from traditional synchronous machine, the rotor of the PMV machine rotates at a definite fraction of the synchronous speed, as if it were geared down from the high rotating field set up by the stator. The PMV machine, therefore, can be regarded as a combination of a gear with fixed gear ratio and an electric machine. This kind of machine is attractive in applications which require low speed and high torque, and mechanical gearing is undesirable.
The main objective of this thesis is to present the design, analysis and control of the proposed PMV machine. After the introduction on mechanical gears, magnetic gears, and low-speed machines, the design details of the proposed outer-rotor PMV machine are provided. Moreover, the working principle, stable torque generation mechanism and structural features are presented.
Due to the introduced vernier effect, it is important to perform the finite element analysis (FEA) for the proposed PMV machine. The electric circuit equation and the motion equation are coupled with the Maxwell’s equation to calculate the key parameters of the proposed machine. The analysis results of the magnetic field distributions, air-gap flux density distributions, flux linkages, winding inductances, back electromotive forces (EMFs), cogging torque and static torque are presented in detail. The performances of PMV machine are compared with other machines to show its advantages and disadvantages.
The control strategy of the PMV machine as a brushless DC machine is also presented. The conventional 120-degree conducting, dual-closed-loop control strategy is used for speed and torque control and the experimental setup are given. The results are obtained and compared with the simulation results, thus verify the validity of the design. Finally, the potential applications for the proposed PMV machine are suggested.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Stavrou, Andreas. "Analysis and simulation of faults in squirrel cage motors". Thesis, University of Aberdeen, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390266.
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Condition based maintenance of electrical machines offers significant advantages for industry. A large part of the research effort in this area is directed towards the evaluation of fault conditions. This thesis is concerned with analysing and modelling faults in induction motors. A method for evaluating the performance of induction machines with static and dynamic eccentricity is developed, using harmonic analysis of the air gap permeance. Models able to simulate eccentricity are presented. The slip ring model equations are obtained and then used to obtain the commutator models transformed to a single reference frame. A variety of effects accompanying these fault conditions are analysed, for example variation of the eccentricity level due to unbalanced magnetic pull and the possibilities of additional vibration harmonics examined. Damping of eccentricity fields due to current redistribution, saturation and slotting are discussed. Some general steady state calculations are also presented which show that the performance of the machine need not be changed over the operating range, due to such a fault. The characteristics of combined static and dynamic eccentricity are examined and it is shown that the combined asymmetry generates additional harmonic components which are not related to those which occur when the two asymmetries take place in isolation. The development of a simulation model of machines with broken rotor bars, based on the variation in rotor parameters is presented. Experimental investigations focus mainly on observable differences in the torque transient characteristics, due to such a condition. The possibilities for using current monitoring to identify inter-turn short circuits are investigated.
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Lim, Lian Hoon. "Transient analysis of cage induction machines using time-stepping finite elements". Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/8781.
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Boast, G. S. "Wide bandwidth control of AC machines". Thesis, University of Sussex, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325931.
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Howgego, David Christopher. "Metal-mediated molecular machines". Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7619.
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Nature abounds with ingenious nanoscopic machines employed to carry out all of the requisite tasks that collectively contribute to the molecular basis of life. This thesis focuses primarily on a sub-set known as "molecular walkers" which can perambulate along intracellular molecular motorways carrying out such essential tasks as vesicle transport and muscle contraction. A summary of these incredible natural motors is presented in Chapter I along with a review of the artificial small-molecule mimics reported to date. When elucidating a set of design principles for synthetic analogues, inspiration is taken from the mechanism of the biological bipedal motor protein kinesin with a focus on potential strategies to enable directional walking. Transition metal-ligand chemistry is utilised as one such strategy in Chapter II through the governance of walker-track interactions in the design, synthesis and operation of a bimetallic molecular biped. A palladium(II) moiety is selectively and intramolecularly stepped between pyridine-derivative binding sites in the track using a thermal stimulus in the presence of a coordinating solvent. Acid-base manipulations facilitate directional stepping by means of an energy ratchet mechanism allowing the track to do work on the biped unit and ultimately drive it away from equilibrium. The potential of malleable transition metal binding-event energetics is explored further in Chapter III with the design and synthesis of a platinum(II)-complexed [2]rotaxane. Thermodynamic and kinetic stimuli are investigated as means to mediate selective shuttling of a Pt-complexed macrocycle between two ligand binding sites in the thread. The substitution pattern of the ligands and the kinetic stability of the metal-ligand bonds afford exceptional metastability to the co-conformers of the molecule in the absence of an external stimulus providing the possibility for long-term information storage. In Chapter IV, a novel macrocycle is used to demonstrate the chemical orthogonality of acid-mediated hydrazone exchange with respect to the palladium(II) stepping mechanism described in Chapter II and show that two such motifs can be independently addressed within a single molecule. These linkages are then utilised as mutually exclusive chemo-selective switches to individually operate opposing feet in an unprecedented first-generation small-molecule walker-track system.
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Niu, Shuangxia y 牛双霞. "Design, control and application of double-stator permanent magnet brushless machines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841677.
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Liu, Chunhua y 劉春華. "Design, analysis, control and application of permanent-magnet hybrid brushless machines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841665.
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Klok, Martin. "Motors for use in molecular nanotechnology". [S.l. : s.n.], 2009.
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Lemouchi, Cyprien. "Moteurs Moléculaires Cristallins Photo-pilotés". Phd thesis, Université d'Angers, 2010. http://tel.archives-ouvertes.fr/tel-00801226.
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L'engouement aujourd'hui pour la manipulation des propriétés électriques des supraconducteurs moléculaires dans le domaine des matériaux, nous a conduit à installer des gyroscopes au sein du cristal, pour que la propriété dynamique puisse moduler l'environnement électrostatique pouvant déboucher vers un nouvel ordre de charge et des structures ferroélectriques. Une machine moléculaire qui possède un rotor, un axe de rotation et des stators tel que le 1,4-diéthynylbicyclo[2,2,2]octane, a été choisie pour sa particularité à interagir avec la lumière, que l'on organise au sein du solide, sous forme de monocristaux appelés moteurs cristallins. La RMN CP/MAS sur poudre cristalline et monocristal a permis de caractériser le mouvement du rotor. Le développement d'une approche cristalline ajouté à la fonctionnalisation des rotors ont permis leur auto-assemblage et leur installation dans des architectures ouvertes organisées autour de cation métalliques (MOF,PCP,), ce qui a permis l'élaboration de matériaux multifonctionnels, dotés de la fonction dynamique, aux propriétés de conductivité ou de transition spin (SCO-MOF). Finalement, l'étude de systèmes cristallins dynamiques de basse dimentionnalité en optique non linéaire a permis de mettre en évidence le phénomène de photo-pilotage des gyroscopes par la lumière au sein du solide. le développement de systèmes plus élaborés permettra de mieux comprendre ce phénomène afin de l'utiliser dans des applications industrielles.
31
Judge, Andy. "Air Gap Elimination in Permanent Magnet Machines". Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-dissertations/123.
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In traditional Permanent Magnet Machines, such as electric motors and generators, power is transmitted by magnetic flux passing through an air gap, which has a very low magnetic permeability, limiting performance. However, reducing the air gap through traditional means carries risks in manufacturing, with tight tolerances and associated costs, and reliability, with thermal and dynamic effects requiring adequate clearance. Using a magnetically permeable, high dielectric strength material has the potential to improve magnetic performance, while at the same time offering performance advantages in heat transfer. Ferrofluids were studied as a method for improved permeability in the rotor / stator gap with a combined experimental and computational approach. Results show promise for the ferrofluid technique. An off-the-shelf motor system showed improved performance with ferrofluids vs. fluids of equivalent viscosity, and improved performance vs. an air gap at low RPM. New generator designs showed design dependent performance gains, although some potential for negative performance effects. A proof of concept generator was built and tested, with increased voltage vs. RPM predicted through virtual prototyping, and validated through experimentation, showing ~10% improvement on voltage vs. RPM at the <600 RPM range. More repeatable engineering tests demonstrated a ~30% increase in the voltage / RPM relationship for designs with an isolated stator chamber and a large stator - rotor gap. However, the effects were negative for a similar system with a small stator-rotor gap due to leakage flux effects. New contributions to the body of knowledge in this area include: • Application of the ferrofluid technique to axial flux designs. • Development of a virtual prototype, including variations in the fluid viscosity due to ferrohydrodynamic effects. • Consideration of negative effects of ferrofluid immersion, such as shear losses and increases in leakage flux. • Optimization of the design to eliminate increased viscous losses. The improved design has been designed, built, and tested, featuring isolation of the ferrofluid from the rotating region. This offers all of the performance gain of improved magnetic permeability, while minimizing the offsetting losses from increased shear effects.
32
Li, Zhou. "Numerical computation of core losses in permanent magnet machines". Thesis, View thesis, 2000. http://handle.uws.edu.au:8081/1959.7/284.
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This thesis presents a study on core loss calculations in rotating electrical machines. The basic concepts concerning magnetic moments, ferromagnetism, magnetic domains and magnetic hysteresis are introduced. The three-term models for alternating and rotational core losses in electrical steel sheets are presented. Several core loss measurement techniques are reviewed and an experiment is carried out to measure the total core losses in an electrical sheet steel sample under alternating and rotational magnetic fields of various frequencies and amplitudes. The coefficients in the loss models for alternating and rotational core losses are obtained through curve fitting process. The theory of electromagnetic fields is presented through the Maxwell equations and field scalar equations. A detailed review on core loss models for rotating electrical machines is presented. A rotational core loss model is adopted to calculate the core losses in a PM motor. The total core loss in the PM motor is obtained by summing the element losses using a MATLAB program. An experiment is conducted to measure the total core loss in the PM motor. The calculated total core loss in the PM motor is compared with the experimental results. The calculated total core losses are about 19% lower than the tested results. Various possible causes for this discrepancy are discussed
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Li, Fuhua y 李富华. "Design, analysis, control and application of permanent magnet brushless dual-memory machines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208621.
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Conventional PM machines have fixed PM excitation and can only perform flux-weakening by controlling the d-axis current. This current incurs the power dissipation and reduces the efficiency during flux-weakening operations.
Memory machines change this situation by introducing the memory function, namely magnetizing or reversely magnetizing Al-Ni-Co PMs to change the air-gap flux density. This provides another new way to realizing flux-weakening. And the elimination of the flux-weakening d-axis current improves the overall efficiency. But the single-memory machines have lower power density due to the low-energy Al-Ni-Co PMs.
By incorporating the memory concept and with the intention of improving the power density, the DC-excited PMBL dual-memory machines have been proposed and implemented, based on two kinds of PMs which are high-coercivity Nd-Fe-B PMs and low-coercivity Al-Ni-Co PMs. The Nd-Fe-B PMs provide a strong magnetic field to excite high air-gap flux density; while the Al-Ni-Co PMs can be forward magnetized to strengthen the magnetic field produced by Nd-Fe-B PMs or can be reversely magnetized to cancel that field. Consequently the air-gap flux density can be controlled within a wide range.
A series of design principles on such kind of dual-memory machine are devised for guidance. The key design principles involve how to determine the number of salient poles on the stator and rotor, how to choose the surface areas and thicknesses of the two kind of PM pieces and how to size the rotor dimension.
Generally, increase on the proportion of Nd-Fe-B PMs will raise the base field and the load capacity. On the other hand, increment on the proportion of Al-Ni-Co PMs will extend the controllable flux range. Analysis is also carried out on the equivalent magnetic circuit to formulate the magnetizing force exerted on Al-Ni-Co PMs.
The machine model is analyzed by using time-stepping FEM (TS-FEM) and co-simulation of FEM software and Matlab Simulink. The dynamic reverse magnetizing processes are simulated and presented in details under different magnetizing current. In addition the effect of adding iron bridges between the two kinds PMs is also evaluated by simulations.
Furthermore, the control methods are evaluate by simulations and experiments. The direct torque control (DTC) scheme is adapted to this doubly-salient dual-memory machine and a torque estimator is proposed to facilitate the DTC method. Both of the simulation results and the experimental results confirm the validity of the proposed design principles and the effectiveness of the control methods.
Eventually, this dual-memory machine is proposed as a pole-changing wind power generator and a pole-changing EV machine. Simulation and experimental results have verified the validity of the pole-changing scheme and the pole-protection scheme.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
34
Schoen, Randy R. "On-line current-based condition monitoring of three-phase induction machines". Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/12952.
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Baco, Joseph C. "A flexible development system for stepper motor based electro-mechanical subassembly design /". Online version of thesis, 1994. http://hdl.handle.net/1850/11982.
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Zhang, Jun Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Direct torque controlled induction machines for integrated starter/alternator system". Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2007. http://handle.unsw.edu.au/1959.4/26224.
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An integrated starter/alternator (ISA) has been proposed for the future 42 V PowerNet, which combines both starter and alternator functions into a single electrical machine with bidirectional power flow ability. This thesis presents analysis, design, modeling and experimental results of the direct torque controlled ISA system based on a low voltage induction machine. The classical direct torque controlled ISA based on switching-table is systematically for an ISA evaluated in this thesis. The simulation and experimental results show that the direct torque control (DTC) concept can be successfully extended to the ISA application. An improved DTC of the ISA based on direct stator flux vector is presented to reduce the drawbacks of high torque and flux ripples of the classical DTC. Robust design of the controller ensures the system is not sensitive to the variation of rotor resistance. By controlling the electromagnetic torque of the induction machine quickly, the required dc bus voltage can be well regulated within the 42 V PowerNet specifications. Another improved DTC of the ISA with direct torque and flux control is also studied. Compared to the direct flux vector control scheme, the calculation of the commanded voltage vector in this scheme only requires the derivative of the stator flux magnitude, which is a dc quantity. In addition, both torque and flux are regulated directly with two independent closed-loops. This scheme is relatively insensitive to the noise. The thesis proposed compensation methods to reduce the effects of switch voltage drops and dead-time on the estimation of the stator flux. Experimental results confirm that the estimation error is reduced with compensation for both motoring and generating modes of the ISA. A closed-loop type of sliding mode flux observer is proposed to reduce the estimation error of the stator flux. Both Simulation and experimental results confirm that the proposed sliding mode observer is insensitive to the stator resistance variation and sensor offsets. A loss minimized scheme with power factor control for the ISA is proposed in this thesis. It provides a simple solution for the efficiency improvement of the induction machine without requiring any speed or load information. The effectiveness of the direct torque controlled induction machine for an integrated starter/alternator system has thus been confirmed and well supported by the studies presented in this thesis.
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Arnold, David Patrick. "Magnetic Machines for Microengine Power Generation". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4854.
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This dissertation presents an investigation of miniaturized magnetic induction and permanent magnet (PM) machines, intended for use in a microengine. Similar to a macroscale turbogenerator, a microengine comprises a small, gas-fueled turbine engine for converting chemical fuel energy into mechanical power and an integrated electrical generator for converting mechanical power to electrical power. The microengine system is proposed as a revolutionary, high power-density source for portable electronics.
In this research, miniaturized magnetic induction machines and PM machines were designed, fabricated, and characterized. Both types of machines used axially directed magnetic fields and were nominally 10 mm in diameter and 1.5-2.3 mm in thickness. Innovative microfabrication techniques were developed to demonstrate the feasibility of integrating magnetic machines within a bulk-micromachined, silicon-based microengine system.
Two-phase, eight-pole induction machines were constructed within silicon substrates using Cu coils in a laminated, slotted ferromagnetic NiFe or CoFeNi stator core. Silicon etching, wafer bonding, and electrodeposition were used to form all of the magnetic machine components. The induction machines were characterized in motoring mode using tethered rotors and demonstrated motoring torques of up to 2.5 uN-m.
Also, three-phase, eight-pole, surface wound PM machines were built using a hybrid microfabrication/assembly approach. The stators were fabricated by electroplating Cu coils on ferromagnetic NiFeMo (Moly Permalloy) substrates. The rotors were formed by assembling a magnetically patterned SmCo PM with a FeCoV (Hiperco 50) back iron. The PM machines were tested as generators with free-spinning rotors, powered by an air-driven spindle, and demonstrated 2.6 W of mechanical-to-electrical power conversion with continuous DC power generation of 1.1 W at 120 krpm rotor speed.
The primary contributions of this work are (1) the demonstration of microfabricated magnetic machines integrated within bulk-micromachined silicon and (2) the demonstration of multi-watt power conversion from a microfabricated PM generator. These achievements represent progress in the ongoing development of silicon-based microengines, but in addition, the fabrication technologies and device structures may find application in other microsystems.
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Kuschel, Sonja. "Artificial molecular machines for synthesis". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/artificial-molecular-machines-for-synthesis(2d7230dd-6194-43c0-94a8-b46fe1bc2120).html.
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In Nature sophisticated molecular machines are responsible for the synthesis of essential biomolecules and natural biopolymers. Inspired by these natural prototypes, scientist have begun to developed artificial systems that are able to perform complex synthetic tasks. Selected state-of-the-art examples, are presented and categorised according to their synthetic function: systems, which can distinguish between substrates and can also be regulated to produce different products, systems that selectively conduct multistep cascade reactions in mixtures of different reactants and systems that operate in a processive and sequence-specific fashion (Introduction).Following these examples, inspired by the ribosome, the synthesis and operation of the first artificial small-molecule machines based on a rotaxane structure capable of performing sequence-specific synthesis of a tri- and tetrapeptide from a molecular template is described. These machines operate through native chemical ligation (NCL), using a macrocyclic cysteine catalyst that iteratively removes proteinogenic amino acids from the strand and transfers them to a peptide elongation site. Successful operation on small scale generated milligram quantities of the peptides with a single sequence, determined by tandem mass spectrometry, corresponding to the original order of the amino acid building blocks on the strand (Chapter 1). Based on these first prototypes the system was extended to molecular machines operating on polymeric tracks. In this context the limits of the NCL mechanism were explored and the concept of the machine operation was investigated on a model system containing a polystyrene backbone with multiple leucine units. Here, machines with an average number of up to five L-leucyl groups were successfully operated. These initial studies represent the groundwork for the operation on longer polymeric systems containing sequences of amino acids (Chapter 2). Machines operating through a native chemical ligation (NCL) mechanism are restricted by a number of limitations: the rate of the reaction, the length and structure of the synthesised peptide, the cleavage of the product and finally the fact that peptide synthesis occurs in a reversed fashion to ribosomal synthesis (from C to N terminus). To overcome those limitations the development towards a 2nd generation molecular machine based on a transacylation catalyst was envisioned. Since this type of catalyst operates via a series of transacylation steps, the size of the transition state is kept the same throughout the operation, allowing access to longer peptides with fewer structural restrictions. Model systems using a thiophenol catalyst and a 1,2,4-triazol catalyst have been investigated (Chapter 3).
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Pérez, Emilio M. "Hydrogen-bonded synthetic molecular machines". Thesis, University of Edinburgh, 2004. http://hdl.handle.net/1842/15610.
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This thesis reports on: 1) the development of two new methods to provoke the translation of the macrocycle along the thread (“shuttling”) in hydrogen bonded, fumaramide-based [2]rotaxanes and 2) the utilization of that movement to provoke a potentially useful response. The fumaramide template is perfectly preorganised to form four intercomponent hydrogen bonds with a benzylic amide macrocycle, affording [2]rotaxanes in “world record” yields. This preorganisation can be disrupted by photo-isomerisation (254 nm) of the E double bond to its Z counterpart. The newly formed maleamide template shows little affinity for the macrocycle. This has previously been exploited to synthesise a light and heat switchable molecular shuttles. A unique tristable molecular shuttle in which the macrocycle can be located in three different “stations” by means of thermal and photochemical stimuli is described in Chapter Two. In Chapter Three an alternative mechanism of shuttling for fumaramide-based molecular shuttles is reported. The reversibility of Diels-Alder chemistry is exploited to synthesise a chemically driven molecular shuttle. A chiral two-station [2]rotaxane in which translational motion of the macrocycle along the thread results in a profound change in its optical properties (CD spectrum) is described in Chapter Four. Finally, a light-switchable optically-addressable molecular shuttle is discussed. A [2]rotaxane with a thread containing a fluorophore and a macrocycle functionalised to quench its fluorescence was synthesised. Shuttling of the macrocycle along the thread switched the fluorescence “on” and “off”.
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Pérez, Carrasco Rubén. "Mechano–chemical study of rotatory molecular motors". Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/108039.
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Cells are the minimum unit of life. They are born, they eat, the may grow, they may move, and, eventually, they die. By contrast, from a physicist point of view, cells are systems out of equilibrium continuously transducing between matter, energy and information. This transduction is what grants the cell their active properties. In order to perform such tasks, cells have a set of macromolecules, a machinery, which are called, Molecular Motors or Molecular Machines. The operation of molecular motors is multiple. For instance, kinesins are molecular motors able to transport cargoes along the cell, or the Bacterial Flagellar Motor works as a nanometric ionic turbine transmitting its rotation to bacterial flagella propelling the cell.
The energy input of such nanometric devices have two primary sources. On one hand the hydrolysis of nucleotide derivatives, such as ATP. On the other hand, molecular motors can also be found in biological membranes obtaining energy from the natural flux of ions crossing the membrane due to mechano-chemical energetic differences at each side.
The recycling of ATP molecules takes place in another molecular machine, the F0F1 ATP synthase. F0F1 is made up of two subunits that can be separated themselves in two different molecular machines. This way, the F1 motor can couple a rotatory motor with the synthesis/hydrolysis of ATP.
Understanding the working of molecular motors is not straightforward. The transduction processes result from a complex set of interactions of all the molecules conforming the motor plus all the interactions with the surrounding molecules. Thus, different approaches with different levels of abstraction are necessary. In the current thesis, molecular motors are studied through the identification of the energetic transduction cycles out of the trajectory of the motor. Trajectories allow to identify the different mechanical and chemical processes driving the motor and allow to propose a spatio-temporal potential for the motor that give information of the energetic performance of the motor such as power and efficiency.
This analysis is performed on the F1 motor (in its hydrolysis regime). Such analysis allowed to identify the origin of two well differentiated mechanical and chemical processes that were quantified by means of the reaction kinetics theory and the overdamped dynamics associated with the nanometric biological scale. From this analysis resulted a prediction for the average velocity of the motor with the experimental control parameters. The resulting velocity matches experimental measures of the average velocity without fitting any parameter since all the parameters needed can be extracted from alternative experimental assays.
The appealing results of the average velocity lead to a proposal of motor potential for the F1 motor consisting on two linear piece-wise potentials flashing between them. Each potential presenting the experimental characteristics observed when the catalytic site of the motor is empty or occupied. The potential also hold the substepping mechanism observed experimentally. Thus, the resulting potential can be tested, together with the overdamped dynamics of the potential and the thermal fluctuations characteristic of the biological cellular scale. This results in a Langevin equation leading the dynamics of the motor. Again, the stochastic dynamics proposed are able to reproduce the velocity of the motor returning a better approximation than the deterministic approach. As happened in the previous case, there is no fitting in the parameters to test the validity of the velocity expression. Actually, the model is able to predict the measured substep angle from optimisation arguments. The mismatch between the deterministic and the stochastic results was identified as a result of a loss of ATP hydrolysis events due to thermal fluctuations that has been also properly quantified through the Fokker-Planck formalism of the corresponding Langevin equation.
The motor potential proposed was also used to study experimental assays of the F1 motor working against conservative forces. The effect of a conservative torque in the working of the motor contains contributions both mechanical and chemical. Altogether, this contributions were successfully addressed presenting again an analytical and stochastic prediction for the velocity of the motor that matches the experimental observations without the need of any parameter fitting. This analysis also entailed a study of the energetic performance of the motor which is unavailable experimentally. The results show a complete divergence between the stochastic and deterministic predictions. The divergence is specially dramatical near the stall force of the motor where the determenistic analysis predicts an efficiency maximum and the stochastic analysis returns a null efficiency. This points out that the stochastic effects are very relevant to the energetic performance of the motor and can not be missed in a proper energetic study of a molecular machine.
Besides the study of the F1 motor, also a rotatory device working with an ionic flux was analised. The aim of the analysis was the devise of a minimal mechanistic turbine and the study of its main working features. Such a machine is composed by a mobile piston with periodic boundary conditions at both ends of a nanometric channel separating two particle reservoirs. Hence, the turbine is able to transduce energy between the flux of ions and an external force hindering the natural motion of the piston. Again, thermal fluctuations provide a stochastic dynamic that must be studied through a Langevin equation that can be tackled analytically. This study revealed that the velocity and the flux are not coupled. Specially, two different stall forces appear for the motor. One for the velocity and one for the flux. This results in an intermediate zone where there is a continuous leakage of ions that does not allow any energetic output. This effect is originated from thermal fluctuations. Thus, when the energetic performance is evaluated, a similar behaviour than the one obtained for the F1 motor is recuperated. This minimal model was extended with more complex turbines that take into account more thoroughly the biophysics of molecular machines. All of them result in the same energetic landscape where a minimum of efficiency is obtained near the stall of the motor.
Additionally, a new formalism has been developed to simplify the resulting Langevin equations (Fokker-planck white noise limit) and a new algorithm has been devised able to integrate Langevin equations with non-continuous multiplicative noiseLos Motores Moleculares son macromoléculas biológicas que se encargan de hacer las transducciones energéticas necesarias dentro de las células. Este trabajo estudia la transformación de energía de motores moleculares rotatorios reales principalmente la F1-ATPasa, el Motor Flagelar de las Bacterias y el F0. Para estudiar la dinámica del motor se han utilizado ecuaciones de Langevin sobreamortiguadas que recogen la importancia de las fluctuaciones térmicas, así como las fuerzas externas aplicadas al motor (conservativas y disipativas) y el potencial interno del motor que contiene la información físico-química de su comportamiento. Este estudio se ha aplicado a la F1-ATPasa, que se puede estudiar tanto analíticamente, obviando las fluctuaciones térmicas como desde su naturaleza estocástica mediante potenciales intermitentes. En ambos casos, el modelo es capaz de describir la dinámica del motor y su dependencia con los diferentes parámetros controlables experimentalmente: Concentración de ATP, fuerza disipativa y fuerza conservativa. En el mismo sentido se ha diseñado una turbina nanoscópica que recoge los principios básicos de la interacción mecánica entre un flujo de iones y la rotación del motor. En ambos casos, tanto en la turbina como en el F1 se observa que el ruido térmico no afecta mucho a la velocidad del motor y en cambio produce cambios enormes en parámetros energéticos como la potencia o la eficiencia. Concretamente, el escenario clásico en que un máximo de eficiencia se obtiene para la fuerza de calado desaparece obteniendo nuevos regímenes óptimos de trabajo. Adicionalmente, se ha desarrollado un formalismo para simplificar las ecuaciones de Langevin obtenidas (límite de ruido blanco) y se ha diseñado un nuevo algoritmo para integrar ecuaciones de Langevin en las cuales el ruido multiplicativo es discontinuo en el espacio.
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Hugel, Thorsten. "Towards Synthetic Molecular Motors Interfaced by AFM". Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-8157.
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Ramsdell, Talia Lynn. "Molecular Motors of ESX-Type Secretion Systems". Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10212.
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Tuberculosis is an enormous global health problem. Despite decades of research, the mechanism(s) by which Mycobacterium tuberculosis (Mtb) mediates virulence remains incompletely understood. The ESX-1 secretion system is critical for Mtb to survive and cause disease in vivo, but its primary function and mechanism of action are unclear. The many inherent challenges of working with this slow-growing pathogen often limit the experimental approaches that can be used to address these questions. Thus, we have developed a model system in the nonpathogenic bacterium Bacillus subtilis to study ESX-type secretion systems. Here, we demonstrate that the B. subtilis yuk operon encodes an ESX-type secretion system responsible for the secretion of YukE. Additionally, we demonstrate that the yuk system is active in B. subtilis during conditions of nutrient deprivation and is required for normal biofilm formation. Interestingly, this is similar to our findings that the Mtb ESX-1 system plays dual roles in protein secretion and modulating cell wall integrity. One defining feature of all ESX loci is the presence of an FtsK/SpoIIIE family ATPase. Interestingly, these ATPases have a domain structure unique to ESX-associated ATPases, where each protein contains multiple (2-3) enzymatic domains. We used our B. subtilis system to dissect the mechanism of action of this unique class of motor proteins. We find that the yuk-encoded ATPase YukBA dimerizes to form a hexamer of enzymatic subunits that are differentially required for secretion. Strikingly, we find a unique requirement for rotational symmetry in the nucleotide binding activity of the subunits. Finally, we compared the energy requirements of the Mtb ESX-1 system and the B. subtilis yuk system. We find that these systems have some overlapping ATPase requirements for protein secretion and cell wall integrity/biofilm formation, suggesting that there is a conservation of function among ESX-type systems. We also find that some ATPase domains are differentially required for function between these two systems, which we postulate is due to the split protein architecture of the ESX-1-encoded ATPases. Together, these findings highlight the power of using a B. subtilis model system to understand the function and mechanism of action of ESX-type secretion systems.
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Su, Xiaolei. "Regulation of Microtubule Dynamics by Molecular Motors". Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10145.
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Kinesin superfamily motors have a well-characterized ability to move along microtubules and transport cargo. However, some members of the kinesin superfamily can also remodel microtubule networks by controlling tubulin polymerization dynamics and by organizing microtubule structures. The kinesin-8 family of motors play a central role in cellular microtubule length control and in the regulation of spindle size. These motors move in a highly processive manner along the microtubule lattice towards plus ends. Once at the microtubule plus end, these motors have complex effects on polymerization dynamics: kinesin-8s can either destabilize or stabilize microtubules, depending upon the context. My thesis work identified a tethering mechanism that facilitates the processivity and plus end-binding activity of Kip3 (kinesin-8 in budding yeast), which is essential for the destabilizing activity of kinesin-8 in cells. A concentration-dependent model was proposed to explain the divergent effects of Kip3 on microtubule dynamics. Moreover, a novel activity of Kip3 in organizing microtubules was discovered: Kip3 can slide anti-parallel microtubules apart. The sliding activity of Kip3 counteracts the depolymerizing activity of Kip3 in controlling spindle length and stability. A lack of sliding activity causes fragile spindles during the process of chromosome segregation in anaphase. The tail domain of Kip3, which binds both microtubules and tubulin dimers, plays a critical role in all these activities. Together, my work defined multiple mechanisms by which Kip3 remodels the microtubule cytoskeleton. The physiological importance of these regulatory mechanisms will be discussed.
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Rakgati, Edward Tshitshiri. "Torque Performance of Optimally Designed Multi-Phase Reluctance DC Machines". Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1174.
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Yu, Chuang y 余创. "Design, analysis and control of flux-mnemonic permanent magnet brushless machines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44769027.
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Li, Wenlong y 李文龙. "Design, analysis and application of low-speed permanent magnet linear machines". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48329721.
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With the growing interests and high requirements in low-speed linear drives, the linear machines possessing high force density, high power density and high efficiency feature become in great demands for the linear direct-drive applications. There are many available linear machine topologies, but their performances for exhibiting the high-force density capability dissatisfy the industrial requirements. In order to solve this problem, the new machine topologies emphasizing on high force density are explored and studied. The objective of this thesis is to present the design, analysis, and application of permanent magnet (PM) linear machines which can offer a higher force density at the same magnetic loading and electric loading than the conventional machines.
Although in recent years there are many emerging advanced PM rotational machines for direct-drive rotational drives, the development of advanced PM linear machines for direct-drive linear drives is sparse. In spite of the motion type of electric machines, the inherent operating principle is the same. By studying and borrowing concepts of the high torque density rotational electric machines, the linear machine morphologies of the promising candidates are designed and analyzed. The problems and side effects resulting from the linearization are discussed and suppressed.
Two main approaches for machine design and analysis are developed and applied, namely the analytical calculation and the finite element method (FEM). By analytically solving the magnetic field problem, the relationships between the field quantities and the machine geometry are unveiled. With the use of analytical calculation, the machine design and dimension optimization are conveniently achieved. With the use of FEM, the machine design objective and its electromagnetic performance are verified and evaluated.
Finally, the proposed low-speed PM linear machine is applied for direct-drive wave power generation. By mathematically modeling the wave power, generation system and the generator, the conditions for maximum power harvesting are determined. By using the vector control, the generator output power is maximized which is verified by the simulation results.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Abbas, Al-Byati N. "The eddy-current damping of synchronous machines with solid cylindrical rotors". Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330125.
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Sitsha, Lizo M. M. "Design of tapered and straight stator pole switched reluctance machines". Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51678.
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Thesis (MEng)--University of Stellenbosch, 2000.ENGLISH ABSTRACT: This thesis deals with the design and optimisation of medium power traction switched reluctance machines with tapered and straight stator poles. Only the prototype of the tapered stator pole machine is constructed and evaluated in this study. A non-commercial finite element package is used in the design and optimisation of the machines. The finite element method is applied directly in the optimisation procedure to optimise the design of the machines in multi-dimensions. The lumped circuit analysis method is used only for the purpose of verifying some of the finite element calculated. It is not used in the optimisation procedure. The performance characteristics of the tapered and straight stator pole machines are compared and discussed and the tapered stator pole machine is found to have better torque performance. Also the calculated and measured static torque versus rotor position characteristics of the tapered stator pole machine are compared and discussed.
AFRIKAANSE OPSOMMING: Die tesis beskryf die ontwerp en optimering van medium drywing trekkrag geskakelde reluktansie masjiene met tapse en reguit stator pole. Slegs 'n prototipe van die tapse stator pool masjien is gebou en geëvalueer. Die masjiene is ontwerp en geoptimeer met behulp van 'n nie-kommersiële eindige element metode pakket. Die eindige element metode is direk in die optimerings algoritme gebruik vir die optimering van die masjiene in multi-dimensies. Die gekonsentreede parameter stroombaananalise is slegs gebruik om sommige van die eindige element berekenings te verifeer. Die vermoës van die tapse en reguit stator pool masjiene is vergelyk en bespreek. Die resultate toon dat die tapse stator pool masjien se draaimoment vermoë beter is as die van die reguit stator pool masjien. Die berekende en gemete statiese draaimoment teenoor rotorposisie van die tapse stator pool masjien is ook vergelyk en bespreek.
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Li, Zhou. "Numerical computation of core losses in permanent magnet machines /". View thesis, 2000. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030901.113715/index.html.
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Thesis (M.Sc (Hons)) -- University of Western Sydney, Nepean, 2000."Submitted for the degree of Master of Engineering (Hons), School of Mechatronic, Computer & Electrical Engineering, University of Western Sydney, Nepean" Includes bibliographical references (leaves 107-114).
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Obaid, Ramzy R. "Detection of rotating mechanical asymmetries in small induction machines". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/13527.
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