Дисертації з теми "Magnetic geometry"
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Kemp, Graham. "Algebra and geometry of Dirac's magnetic monopole." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12508.
Повний текст джерелаGoode, Brent. "Plasma response to waves in arbitrary magnetic field geometry." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/cr/colorado/fullcit?p3190342.
Повний текст джерелаMussa, Ali Ibrahim Al. "Convection and magnetoconvection problems in rapidly rotating spherical geometry." Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324033.
Повний текст джерелаPapaharilaou, Yannis. "Studies of fluid flow in arterial bypass grafts by magnetic resonance imaging." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271254.
Повний текст джерелаBenedetti, Gabriele. "The contact property for magnetic flows on surfaces." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/247157.
Повний текст джерелаPedersen, H. "Geometry and magnetic monopoles : Constructions of Einstein metrics and Einstein-Weyl geometries." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.353118.
Повний текст джерелаHerbrich, Peter. "Spectral aspects of broken drums and periodic magnetic Schrödinger operators." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607685.
Повний текст джерелаMeng, Jinglei. "Effect of geometry and anisotropy on the magnetic moment of type II superconductors." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/9911.
Повний текст джерелаNsibi, Mohamed Ali. "Asymmetric magnetic domain walls motion in a two-dimensional geometry : causes and effects." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY047.
Повний текст джерелаThe study of the current-induced magnetic domain walls motion has attracted a lot of interest since the report of their large velocities of motion in thin layers with structural inversion asymmetry (SIA). This interest comes from their high potential for low power consumption functionalities in cache and main memories applications. The SIA induces two mechanisms whose combined action allows to drive efficiently the domain walls. The two mechanisms are the chiral energy term, called the Dzyaloshinskii-Moriya interaction (DMI), and the spin-orbit torques (SOT). This model is still incomplete since it does not explain several experimental results. In addition, a chiral dissipation term called the chiral damping, also induced by SIA, has recently been proposed. However, its effect on current-induced domain wall motion has not been studied.The objective of this work was to bring a more detailed understanding of the interactions involved in the domain wall motion. To that end, I have studied the domain wall motion in a non-collinear geometry with respect to the current, in materials with different SIA (Pt/Co/Pt and Pt/Co/AlOx). This motion has been found to be asymmetric. It illustrates the interplay between chiral energy and chiral dissipation in current-induced domain wall motion in weak SIA materials. In large SIA materials, the DMI and SOT model, even in the flow regime of motion, cannot explain this asymmetry. I have also evidenced that the asymmetric non-collinear domain wall motion induces a well-defined deflection of the skyrmion bubbles. This is the first observation of the extrinsic skyrmion Hall effect.The results of this thesis contribute to the understanding of the physical mechanisms behind domain wall and skyrmion motion in ultrathin layers by evidencing supplementary effects from SIA
Körs, Boris. "Open strings in magnetic background fields." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2001. http://dx.doi.org/10.18452/14635.
Повний текст джерелаWe discuss various aspects of internal magnetic background fields in open string theories. Phenomenologically and conceptually interesting properties of such string theory backgrounds, supersymmetry and gauge symmetry breaking, chiral fermion spectra and noncommutativity of the internal compactification manifolds, are treated in a rather generic framework. We then specialize to type I compactifications on tori and toroidal orbifolds with magnetic fields on the internal space. This allows to develop a strategy for constructing type I vacua with attractive low energy field theories which may either be supersymmetric or not and contain chiral spectra and gauge groups close to the Standard Model or some grand unified generalization thereof. The most sophisticated version uses magnetic fields and NSNS B-fields on orbifold spaces giving rise to a plethora of promising examples for semi-realistic string compactifications. We finally also present a related class of asymmetric orbifolds of type I which are of little phenomenological interest but still display certain interesting features. The asymmetric rotations which are gauged in these models identify D-branes with different values for the magnetic field on their world volume, such that the distinction of commutative and noncommutative internal geometries is lost.
Cui, Han. "Constant-Flux Inductor with Enclosed-Winding Geometry for Improved Energy Density." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/34722.
Повний текст джерелаMaster of Science
Golebiowski, Andrzej. "Investigation of the effect of flux cutting on magnetic behaviour in hollow cylindrical geometry." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5234.
Повний текст джерелаYuen, Rai. "Pulsar Magnetosphere Revisited: Emission Geometry and the Synthesis of the Vacuum-Dipole and the Rotating-Magnetosphere Models." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10011.
Повний текст джерелаSkoczelas, Brenda M. "A mathematical model for calculating the effect of toroidal geometry on the measured magnetic field." Muncie, Ind. : Ball State University, 2009. http://cardinalscholar.bsu.edu/714.
Повний текст джерелаKaji, Shuichiro. "Annular Geometry in Patients With Chronic Ischemic Mitral Regurgitation: Three-Dimensional Magnetic Resonance Imaging Study." Kyoto University, 2008. http://hdl.handle.net/2433/124334.
Повний текст джерелаGallo, Alberto. "Impact of the plasma geometry on the divertor power exhaust in a magnetic fusion reactor." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0001/document.
Повний текст джерелаA deep understanding of plasma transport at the edge of a magnetically confined fusion device is mandatory for a sustainable and controlled handling of the power exhaust. In the next-generation fusion device ITER, technological limits constrain the peak heat flux on the divertor. For a given exhaust power the peak heat flux is determined by the extent of the plasma footprint on the wall. Heat flux profiles at the divertor targets of X-point configurations can be parametrized by using two length scales for the transport of heat in SOL. In this work, we challenge the current interpretation of these two length scales by studying the impact of divertor geometry modifications on the heat exhaust. In particular, a significant broadening of the heat flux profiles at the outer divertor target is diagnosed while increasing the length of the outer divertor leg. Modelling efforts showed that diffusive simulations well reproduce the experimental heat flux profiles for short-legged plasmas. Conversely, the broadening of the heat flux for a long divertor leg is reproduced by a turbulent model, highlighting the importance of turbulent transport not only in the main SOL but also in the divertor. These results question the current interpretation of the heat flux width as a purely main SOL transport length scale. In fact, long divertor leg magnetic configurations highlighted the importance of asymmetric divertor transport. We therefore conclude that main SOL and divertor SOL transport cannot be arbitrarily disentangled and we underline the importance of the divertor magnetic geometry in enhancing asymmetric turbulent transport with the potential benefit of an unexpected power spreading
Gallo, Alberto. "Impact of the plasma geometry on the divertor power exhaust in a magnetic fusion reactor." Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0001.
Повний текст джерелаA deep understanding of plasma transport at the edge of a magnetically confined fusion device is mandatory for a sustainable and controlled handling of the power exhaust. In the next-generation fusion device ITER, technological limits constrain the peak heat flux on the divertor. For a given exhaust power the peak heat flux is determined by the extent of the plasma footprint on the wall. Heat flux profiles at the divertor targets of X-point configurations can be parametrized by using two length scales for the transport of heat in SOL. In this work, we challenge the current interpretation of these two length scales by studying the impact of divertor geometry modifications on the heat exhaust. In particular, a significant broadening of the heat flux profiles at the outer divertor target is diagnosed while increasing the length of the outer divertor leg. Modelling efforts showed that diffusive simulations well reproduce the experimental heat flux profiles for short-legged plasmas. Conversely, the broadening of the heat flux for a long divertor leg is reproduced by a turbulent model, highlighting the importance of turbulent transport not only in the main SOL but also in the divertor. These results question the current interpretation of the heat flux width as a purely main SOL transport length scale. In fact, long divertor leg magnetic configurations highlighted the importance of asymmetric divertor transport. We therefore conclude that main SOL and divertor SOL transport cannot be arbitrarily disentangled and we underline the importance of the divertor magnetic geometry in enhancing asymmetric turbulent transport with the potential benefit of an unexpected power spreading
Szita, Sarah. "Variability of 40-3000keV electrons at geosynchronous orbit." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286686.
Повний текст джерелаShi, Yuanjing. "Investigation of island geometry variations in bit patterned media storage systems." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/investigation-of-island-geometry-variations-in-bit-patterned-media-storage-systems(b16092b6-7260-4dc5-aa30-7dabb2c7a46f).html.
Повний текст джерелаPardo, Vivé Enric. "Geometry Effects on the Electromagnetic Properties of Linear Magnetic Materials and Superconductors in the Critical State." Doctoral thesis, Universitat Autònoma de Barcelona, 2004. http://hdl.handle.net/10803/3356.
Повний текст джерелаEl comportament electromagnètic d'un cert material no només depèn de les seves propietats intrínseques sinó també de la geometria de la mostra estudiada. De fet, algunes magnituds magnètiques en mostres del mateix material però geometria diferent poden diferir en varis ordres de magnitud.
La tesi està dividida en dues parts. La primera part està dedicada a l'estudi dels efectes de geometria, també denominats efectes desimantadors, en mostres de materials lineals, homogenis i isòtrops (LHI) sota l'aplicació d'un camp magnètic uniforme. Per quantificar els efectes desimantadors en les magnituds magnètiques més rellevants en materials LHI s'utilitzen els factors de desimantació fluxmètric i magnetomètric (Nf i Nm); el seu càlcul teòric és necessari per poder determinar algunes propietats intrínseques dels materials a partir d'experiments. Després de detectar grans mancances en els resultats teòrics previs dels factors de desimantació per prismes rectangulars, presentem nombrosos càlculs originals de Nf i Nm. Pels casos de prismes infinitament llargs i prismes quadrats finits Nf i Nm es calculen per un rang ampli de relació gruix-amplada i susceptibilitat magnètica. Pel cas d'un prisma finit perfectament diamagnètic es presenta un estudi sistemàtic dels factors de desimantació en funció de les dimensions relatives del prisma a partir de càlculs precisos. També es calculen resultats numèrics per cilindres amb camp aplicat en la direcció radial, situació per la que existien molt poques dades.
L'altra part de la tesi consisteix en un estudi de superconductors durs, que són materials molt interessants per aplicacions pràctiques. En aquest cas, l'estudi es centra en algunes geometries infinitament llargues immerses en un camp magnètic altern i uniforme aplicat en direcció transversal o bé que transporten un corrent elèctric altern. Concretament, s'estudien amb detall les geometries de prisma infinit de secció rectangular, el·líptica i varis casos de conjunts de múltiples prismes rectangulars. L'estudi d'aquestes geometries és de gran importància pràctica a l'hora de dissenyar cintes i cables superconductors per treballar en dispositius elèctrics en corrent altern, pels que és fonamental la reducció de les pèrdues energètiques per la viabilitat de la tecnologia basada en cables superconductors. Per fer l'estudi esmentat es desenvolupa un mètode numèric basat en el model d'estat crític per superconductors i la minimització de l'energia magnètica. Pels casos de camp magnètic aplicat, el mètode permet descriure dos tipus de connexió entre filaments, elèctricament aïllats un a un o interconnectats entre sí al extrems dels prismes. Malgrat que el primer tipus de connexió és la que presenta pèrdues energètiques més baixes, no havia estat possible simular-lo fins ara. Els resultats numèrics obtinguts a partir d'aquest mètode són originals i de gran precisió. A més, la descripció sistemàtica del problema permet realitzar un estudi en profunditat de les propietats electromagnètiques per aquestes geometries, gràcies al que s'obtenen unes tendències bàsiques per reduir les pèrdues energètiques.
The electromagnetic behaviour of a certain material do not only depends on its internal properties but also on the geometry of the studied sample. Actually, some magnetic quantities in samples of the same material but different geometry can vary in several orders of magnitude.
The thesis is divided into two parts. In the first part we study the geometry effects, also called demagnetizing effects, in samples made of linear homogenous isotropic materials (LHI) subjected to a uniform applied magnetic field. In order to quantify the demagnetizing effects on the most relevant magnetic quantities of the samples, we carry out accurate calculations for the fluxmetric and magnetometric demagnetizing factors (Nf and Nm); the calculation of these factors is needed to determine some internal magnetic properties of materials from experiments. After detecting some important lacks in the already existing theoretical results for rectangular prisms, we present a complete set of original calculated data of Nf and Nm. For the cases of infinitely long rectangular prisms and finite square bars we calculate Nf and Nm for a wide range of thickness-to-width aspect ratio and magnetic susceptibility. For the case of a perfectly shielding rectangular prism, we present a systematic study of the demagnetizing factors as a function of the relative dimensions of the prism by means of accurate numerical calculations. Numerical results are also presented for cylinders under radial applied field, situation for which there existed very few data.
The other part of the thesis consists in a study of hard superconductors, which are materials very interesting for applications. For this case, we have focused on some infinitely long geometries subjected to either a transverse AC applied field or a transport alternating current. Specifically, there have been studied in detail the geometries of an infinitely long prism with rectangular cross-section, elliptical one and some arrangements of several rectangular prisms. The study of these geometries is of great practical importance for the design of superconducting tapes and cables for devices operating in AC conditions, for which the reduction of the AC loss is of vital importance for the viability of the technology based on superconducting wires. In order to do such an study, we develop a numerical method based on the critical-state model for superconductors and magnetic energy minimization. For the cases considering an applied magnetic field, the method allows the description of two different kinds of filament connexion, mutually electrically isolated or interconnected at the ends of the prisms. Although the first kind of connection presents lower AC loss, this situation has not been simulated until now by any author. The numerical results obtained from this method are original and very accurate. Furthermore, the systematic study of the problem provides a deep understanding of the electromagnetic properties for these geometries, thanks to which we obtain some general trends to reduce the AC loss.
Hughes-Riley, Theodore, John Beau Webber, Michael Ian Newton, and Robert H. Morris. "Magnetic resonance relaxation measurements using open-geometry sensors to assess the clog state of constructed wetlands." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-178572.
Повний текст джерелаHughes-Riley, Theodore, John Beau Webber, Michael Ian Newton, and Robert H. Morris. "Magnetic resonance relaxation measurements using open-geometry sensors to assess the clog state of constructed wetlands." Diffusion fundamentals 22 (2014) 3, S. 1-8, 2014. https://ul.qucosa.de/id/qucosa%3A13476.
Повний текст джерелаLeonard, Amaury. "Aspects of higher spin Hamiltonian dynamics: Conformal geometry, duality and charges." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/253872.
Повний текст джерелаDoctorat en Sciences
info:eu-repo/semantics/nonPublished
Leonard, Amaury. "Aspects of higher spin Hamiltonian dynamics: Conformal geometry, duality and charges." Doctoral thesis, Universite Libre de Bruxelles, 2017. https://dipot.ulb.ac.be/dspace/bitstream/2013/253872/4/main.pdf.
Повний текст джерелаDoctorat en Sciences
info:eu-repo/semantics/nonPublished
Voss, Kimberly Jo. "Investigation of the internal geometry and mechanics of the human fingertip, in vivo, using magnetic resonance imaging." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43454.
Повний текст джерелаHahn, Artur [Verfasser], and Jürgen P. [Akademischer Betreuer] Debus. "Artificial magnetic resonance contrasts based on microvascular geometry: A numerical basis / Artur Hahn ; Betreuer: Jürgen P. Debus." Heidelberg : Universitätsbibliothek Heidelberg, 2021. http://d-nb.info/1237324033/34.
Повний текст джерелаJureit, Jan-Hendrik [Verfasser]. "A braided quasi quantum group from strings in a magnetic field & two applications of noncommutative geometry / Jan-Hendrik Jureit." Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019752777/34.
Повний текст джерелаSeland, John Georg. "Dynamic correlations between inhomogeneous magnetic fields, internal gradients, diffusion and transverse relaxation, as a probe for pore geometry and heterogeneity." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-178804.
Повний текст джерелаSeland, John Georg. "Dynamic correlations between inhomogeneous magnetic fields, internal gradients, diffusion and transverse relaxation, as a probe for pore geometry and heterogeneity." Diffusion fundamentals 22 (2014) 10, S. 1-5, 2014. https://ul.qucosa.de/id/qucosa%3A13490.
Повний текст джерелаDouros, Ioannis. "Towards a 3 dimensional dynamic generic speaker model to study geometry simplifications of the vocal tract using magnetic resonance imaging data." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0115.
Повний текст джерелаIn this thesis we used MRI (Magnetic Resonance Imaging) data of the vocal tract to study speech production. The first part consist of the study of the impact that the velum, the epiglottis and the head position has on the phonation of five french vowels. Acoustic simulations were used to compare the formants of the studied cases with the reference in order to measure their impact. For this part of the work, we used 3D static MR (Magnetic Resonance) images. As speech is usually a dynamic phenomenon, a question arose, whether it would be possible to process the 3D data in order to incorporate dynamic information of continuous speech. Therefore the second part presents some algorithms that one can use in order to enhance speech production data. Several image transformations were combined in order to generate estimations of vocal tract shapes which are more informative than the original ones. At this point, we envisaged apart from enhancing speech production data, to create a generic speaker model that could provide enhanced information not for a specific subject, but globally for speech. As a result, we devoted the third part in the investigation of an algorithm that one can use to create a spatiotemporal atlas of the vocal tract which can be used as a reference or standard speaker for speech studies as it is speaker independent. Finally, the last part of the thesis, refers to a selection of open questions of the field that are still left unanswered, some interesting directions that one can expand this thesis and some potential approaches that could help someone move forward towards these directions
Awe, Thomas J. "Experimental investigation of the properties and phase state of thick aluminum surfaces pulsed to megagauss level magnetic field in a Z-pinch geometry." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3387802.
Повний текст джерелаMurnyack, Roberta Michelle. "Development of a three-dimensional finite element model of lateral controlled cortical impact injury in the rat with geometry from magnetic resonance imaging." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17058.
Повний текст джерелаMichal, Mikuláš. "Rozvinutí elektroniky a softwaru na robotickém vozidle Car4." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444973.
Повний текст джерелаMahariq, Ibrahim M. I. "A Normalized Set Of Force And Permeance Data For Doubly-salient Magnetic Geometries." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610561/index.pdf.
Повний текст джерелаfirst, comparing the numerical results with analytically calculated permeance, second, by solving two switch reluctance motors and comparing the results with the measurements of static torque and flux linkage. The third step is by using the normalized data obtained by solving the model with the aid of an available software that is capable to predict the behavior of switched reluctance motors. Once the reliability of the data is assured, the desired data set is produced and presented in tables.
Hager, Robert [Verfasser], Klaus [Akademischer Betreuer] Hallatschek, and Harald [Akademischer Betreuer] Friedrich. "Radial propagation of geodesic acoustic modes : Analysis of magnetic geometry, nonlinear and non-Boussinesq properties of oscillating flows / Robert Hager. Gutachter: Harald Friedrich. Betreuer: Klaus Hallatschek." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1019588713/34.
Повний текст джерелаBolton, Timothy. "Optimal design of electrically-small loop antenna including surrounding medium effects." Thesis, Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54836.
Повний текст джерелаOrozco, Henao Juan Manuel 1989. "Efeitos de tamanho e geometria nas propriedades magnéticas e de hipertermia magnética em nanopartículas de Fe3O4." [s.n.], 2016. http://repositorio.unicamp.br/jspui/handle/REPOSIP/305751.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-30T18:13:51Z (GMT). No. of bitstreams: 1 OrozcoHenao_JuanManuel_M.pdf: 7687296 bytes, checksum: d9aecf2d118aed0c43ab747d0dcff34c (MD5) Previous issue date: 2016
Resumo: Nanopartículas de magnetita com diâmetros entre 5nm e 19nm sintetizadas mediante um método de decomposição térmica são apresentadas. A caracterização estrutural é feita usando diferentes técnicas experimentais como a microscopia eletrônica de transmissão (TEM), difração de raios-X e espalhamento de raios-X a baixos ângulos (SAXS) de onde são obtidos os tamanhos e a forma das nanopartículas. As propriedades magnéticas e de magneto-hipertermia das nanopartículas são estudadas para diferentes parâmetros de produção como concentração dos surfactantes, temperaturas de refluxo e atmostfera de crescimento. A dependência com a temperatura das propriedades magnéticas são analisadas dentro do marco do modelo usual do superparamagnetismo e o modelo de interação superparamagnética (ISP), de onde os parâmetros magnéticos dependentes do tamanho como anisotropia magnética (1.06x10^4 J/m^3 até 9.91x10^4 J/m^3), momento magnético por partícula (2618?B até 11500?B), temperatura de bloqueio (18K até mais de 300K) e energia de ineração dipolar magnética (0.55x10^-21 J até 5.5x10^-21 J) são inferidos. Os resultados de magneto-hipertermia foram obtidos mediante a medição da resposta térmica das nanopartículas de magnetita suspendidas em tolueno. Valores da taxa de absorção específica (SAR) são calculados experimental e teoricamente utilizando a teoria de resposta linear para um sistema superparamagnético não interagente. Valores de SAR entre 3.0W/g e 40.3W/g e a sua dependência com a frequência e o campo aplicado são apresentados. Como resultado interessante, a resposta de magneto-hipertermia para as nanopartículas de 19nm preparadas na presença de oxigênio e mais de 10 vezes maior do que nanopartículas similares mas obtidas na ausência da atmosfera de oxigênio. Também é destacada a possibilidade de prever a resposta de magneto-hipertermia num sistema de nanopartículas magnéticas mediante a obtenção dos parâmetros de caracterização magnetica e estrutural
Abstract: Magnetite nanoparticles with diameters between 5nm and 19nm synthesized by means of a thermal decomposition method are presented. Structural characterization is made by different experimental techniques such as transmission electron microscopy (TEM), X-ray diffraction and Small Angle X-ray Scattering (SAXS) from where nanoparticles size and shape are obtained. Magnetic and magneto-hyperthermia properties of the nanoparticles are studied for different production parameters, such as surfactant concentrations, refluxing temperature and growth atmosphere. Temperature dependence of the magnetic properties are analyzed in the framework of the standard superparamagnetism model and the interacting superparamagnetic model (ISP), from where size dependent magnetic parameters for each sample such as anisotropy (1.06×10^4 J/m^3 to 9.91x10^4 J/m^3) magnetic moment per particle (2618?B to 11500?B), blocking temperature (18K to above 300K) and magnetic dipolar interaction energy on dried nanoparticle samples (0.55 × 10^?21 J to 5.5 × 10^?21 J) are inferred. Magneto-hyperthermia results are obtained by measuring the thermal response of magnetite nanoparticles dissolved in toluene. Specific absorption rate (SAR) values are theoretically and experimentally calculated by means of a linear response theory approach of a non-interacting superparamagnetic system. SAR values between 5.8W/g and 40.3W/g are reported; interestingly, the magneto-hyperthermia response for 19nm nanoparticles prepared in presence of an oxygen atmosphere is more than 10 times larger than similar particles obtained in absence of oxygen atmosphere. Also it is important to highlight the possibility to obtain the magneto-hyperthermia behavior of a magnetic nanoparticles system by knowing a priori its structural and magnetic characterization parameters
Mestrado
Física
Mestre em Física
1247647/2013
CAPES
Buhl, Matthias. "Spin Transfer Torque-induziertes Schalten von Nanomagneten in lateraler Geometrie bei Raumtemperatur." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-139909.
Повний текст джерела“Changing and detecting the orientation of nanomagnetic structures, which can be used for durable information storage, needs to be developed towards true nanoscale dimensions for keeping up the miniaturization speed of modern nano electronic components. Therefore, new concepts for controlling the state of nano magnets are currently in the focus of research in the field of nanoelectronics. Here, we demonstrate reproducible switching of a purely metallic nanopillar placed on a lead that conducts a spin-polarized current at room temperature. Spin diffusion across the metal-metal (Cu to CoFe) interface between the pillar and the lead causes spin accumulation in the pillar, which may then be used to set the magnetic orientation of the pillar by means of Spin Transfer Torque (STT). In our experiments, the detection of the magnetic state of the nanopillar is performed by direct imaging via scanning transmission x-ray microscopy (STXM)” [1]. Therefore it could be demonstrated, to reversibly switch the nanopillar’s magnetic state even against the Oersted field which is induced by the switching current. Furthermore we could show, that magnetization switching is possible by a pure spin current that is diffusively transported beneath the nanopillar
Grosjean, Alex. "Impact of geometry and shaping of the plasma facing components on hot spot generation in tokamak devices." Electronic Thesis or Diss., Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0556.
Повний текст джерелаThis PhD falls within ITER project support, aiming to study the thermal behavior of ITER-like PFC prototypes in two superconducting tokamaks: EAST (Hefei) and WEST (Cadarache). These prototypes correspond to castellated tungsten monoblocks placed along a cooling tube with small gaps (0.5 mm) between them, called plasma-facing units, to extract the heat from the components. The introduction of gaps between monoblocks (toroidal) and plasma-facing units (poloidal), to relieve the thermomechanical stresses in the divertor, implies that poloidal leading edges may be exposed to near-normal incidence angle. A local overheating is expected in a thin lateral band at the top of each monoblocks, which can be enhanced when the neighboring components are misaligned. In this work, we propose to study the impact of two geometries (sharp and chamfered LEs) of these components, as well as their misalignments on local hot spot generation, by means of embedded diagnostics (TC/FBG), and a submillimeter infrared system (~0.1 mm/pixel), whose emissivity varies with wavelength, and the temperature, but above all, the surface state of the component, which evolves under plasma exposure, during the experimental campaigns. The divertor Langmuir probes measure the plasma temperature, and thus estimate the ion Larmor radius that may play a role in the local heat flux distribution around poloidal and toroidal edges. The results presented in this thesis, confirming the modelling predictions by experimental measurements, support the final decision by ITER to include 0.5 mm toroidal beveling of monoblocks on the vertical divertor targets to protect poloidal leading edges from excessive heat flux
Cekić, Mihajlo. "The Calderón problem for connections." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/267829.
Повний текст джерелаLIMA, VINICIUS DE CARVALHO. "GEOMETRIC MAGNETIC DISCRIMINATOR SENSOR FOR SMART PIGS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5859@1.
Повний текст джерелаFINANCIADORA DE ESTUDOS E PROJETOS
Este trabalho apresenta o desenvolvimento de um sensor inovador combinando três técnicas de inspeção utilizadas nos Pigs Instrumentados Geométrico e Magnético, para a detecção e caracterização de defeitos na geometria em tubulações de aço. O sensor GMD, Geométrico Magnético Discriminador, faz a leitura magnética do duto através da técnica de campo de fuga magnético, com a adição da leitura geométrica além da discriminação de defeitos internos de externos. A combinação dessas três tecnologias habilita a construção de uma ferramenta de inspeção de alta resolução compacta e capaz de identificar e quantificar, com apenas uma coroa de sensores, amassamentos, perdas de espessura e além da sua combinação. Este estudo se apresenta em um momento oportuno, já que a Integração de dados é o ponto fundamental da recente norma de gerenciamento de ricos em dutos, API 1160, na qual combinando os resultados das inspeções de geometria e corrosão, tem-se uma melhor avaliação de risco. Testes foram realizados utilizando um PIG Plano com corpos de prova contendo defeitos variados. Os resultados verificaram que o sensor GMD quantifica e discrimina amassamentos com perda de espessura. Aspectos técnicos do desenvolvimento como os detalhes construtivos do sensor, testes de avaliação a resultados de laboratório são apresentados.
This thesis presents the development of an innovative sensor head for detection and characterization of geometric defects in steel pipes that combines three inspection techniques usually employed separately in Caliper and Magnetic Flux Leakage (MFL) PIGs. The novel Geometric Magnetic Discriminator (GMD) sensor performs high- resolution magnetic pipeline readings using MFL with the addition of internal pipe geometry evaluations and discrimination between internal and external defects. The combination of these technologies in a single sensor facilitates characterization of dents and corrosions, while at the same time optimizing the PIG set-up. According to the repair criteria in the standard API1160, combined defects such as a dent with metal loss, which in the past could only be detected through combined data of two different runs (MFL+ Caliper), must be repaired immediately. The GMD sensor was tested in a linear test rig, known as Flat Pig, and data were taken from different defect sets. Evaluation tests demonstrated that the GMD sensor sizes and discriminates a dent with metal loss. Technical aspects of the development, e.g.: the construction details of the sensor, evaluation tests and laboratory results are presented.
Calder, S. "Investigation of geometric frustration in magnetic oxides." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/20165/.
Повний текст джерелаYang, Ning. "Synchrotron Diffraction Studies of Spontaneous Magnetostriction in Rare Earth Transition Metal Compounds." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/835381-gxv1Km/webviewable/.
Повний текст джерелаLaribi, Elias. "Modélisation numérique de l'impact de la géométrie magnétique sur le plasma de bord des tokamaks." Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0298.
Повний текст джерелаThis phD work has shown that, in a limiter configuration, the elongation of magnetic surfaces has a stabilizing effect with respect to the edge plasma turbulence. This leads to a reduction of the edge plasma width when the elongation increases. Regarding triangularity, this phD work revealed that its effects on the edge plasma were weaker than those of elongation. A better understanding of these trends has been possible thanks to a theoretical work on a simplified interchange model. This work has also revealed the importance of the magnetic field spatial variability on the poloidal size of turbulent structures and therefore on the radial turbulent fluxes. In a second step, the study of a divertor configuration with one X point has shown that the the magnetic field spatial variability was so important that it could be one of the reasons that explain the enhancement of the low field side ballooned nature of edge plasma turbulence in a divertor geometry. Still concerning the divertor geometry, this phD also revealed that the internal material receives more heat compared to the external material when the toroidal magnetic field is oriented in the direct direction (= magnetic drift of the ions pointing towards the X point). A possible explanation of this observation is the existence of a significant plasma circulation from the low field side to the high field side at the X point that we observed in this configuration. Finally, we were able to confirm that one way to improve this heat flux distribution on the walls was to merge two X points perfectly (= ideal snowflake proposed in 2007 by Ryutov and Sukhanovsky)
Laidlaw, David H. Barr Alan H. "Geometric model extraction from magnetic resonance volume data /." Diss., Pasadena, Calif. : California Institute of Technology, 1995. http://resolver.caltech.edu/CaltechETD:etd-10152007-132141.
Повний текст джерелаChen, Way Cherng. "Magnetic susceptibility-based white matter magnetic resonance imaging techniques." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:7272b7e6-1fb9-4a1b-a71f-2ce5dfe93fde.
Повний текст джерелаMatcha, Chaitanya Kumar, Mohsen Bahrami, Shounak Roy, Shayan Garani Srinivasa, and Bane Vasic. "Generalized belief propagation based TDMR detector and decoder." IEEE, 2016. http://hdl.handle.net/10150/622831.
Повний текст джерелаMazzoni, Michele. "A fibre bundle approach to U(1) symmetries in physics." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16776/.
Повний текст джерелаMoslemzadeh, Nasser. "Geometric and electronic structure of dysprosium thin films on tungsten surfaces." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250404.
Повний текст джерелаSinclair, E. C. "Geometric reaction forces in billiards." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294868.
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