Dissertations / Theses on the topic 'Electromagnetism – materials'
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O'Dell, Ryan Andrew. "Resonant Ferromagnetic Absorption and Magnetic Characterization of Spintronic Materials." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1533043360679487.
Full textMyers, Joshua Allen. "Nano-scale RF/Microwave Characterization of Materials' Electromagnetic Properties." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1340883872.
Full textCiracì, Cristian. "Study of second-harmonic generation in nonlinear nanostructured materials." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20053.
Full textThe past twenty years have been exceptionally rich on the study and fabrication of nanostructured materials to control light, but no much attention was given to nonlinear optical properties of these novel materials. In this context, the present thesis would partially address this gap. In particular, we focus on the second-harmonic generation process, by considering two fundamental aspects: the second-harmonic emission control by means of nanostructured nonlinear materials and the conversion enhancement in integrated photonic devices. A novel nonlinear localization phenomenon occurring in left-handed materials and involving isotropic phase-matching is presented. We analytically demonstrate the localization process in a homogenous left-handed material and by numerical simulation we show the effect for nonlinear photonic crystals. The backward second-harmonic localization effect is used to design a second-harmonic lens. This interesting theoretical result is numerically shown for a feasible structure working at optical frequencies. The second-harmonic generation enhancement is the complementary aspect. By taking advantage of the strong light localization achieved in finite size dielectric nonlinear nanorod chains, we show that sub-wavelength transversal confinement, together with the resonant phase-matching condition, adds an important property to the second-harmonic generation enhancement. A study of linear propagation properties of nanorod chain structures first evidences its sub-wavelength guiding capabilities. Finally, the phase-matching condition that assures the maximal nonlinear interaction in this kind of structure is presented
Meyendorf, Robert. "Nondestructive Determination of Case Depth in Surface Hardened Steels by Combination of Electromagnetic Test Methods." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1303834395.
Full textParsa, Nitin. "MILLIMETER-WAVE FARADAY ROTATION FROM FERROMAGNETIC NANOWIRES AND MAGNETOELASTIC MATERIALS." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1561468969375731.
Full textVishal, Kumar. "Nonreciprocal magnetostatic surface wave in thin ferromagnetic film." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1472018768.
Full textKung, Christopher W. "Development of a time domain hybrid finite difference/finite element method for solutions to Maxwell's equations in anisotropic media." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1238024768.
Full textRoberts, Anthony M. "Implementing a Piezoelectric Transformer for a Ferroelectric Phase Shifter Circuit." Cleveland State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=csu1337025849.
Full textChung, Jae-Young. "Broadband Characterization Techniques for RF Materials and Engineered Composites." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1269542888.
Full textHansen, Matthew Martin Kenneth. "Optimization of Conformal Joints in Axial Tension." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1355847865.
Full textSamuel, Paulo. "Investigating how Grade 10 Physical Science teachers help learners to make sense of concepts of electromagnetism using easily accessible materials in under-resourced schools." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/8143.
Full textMougin, Alexandra. "Anisotropie magnétique, structure en domaines et renversement d'aimantation : déformations, couplages, champ magnétique et courant électrique comme leviers d'action." Habilitation à diriger des recherches, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00638870.
Full textUckert, Kyle. "High Temperature Resistivity and Hall Effect Measurements of Conductive and Semiconductive Thin Films." Ohio University Honors Tutorial College / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1276713762.
Full textApaydin, Nil. "Novel Implementations of Coupled Microstrip Lines on Magnetic Substrates." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1373897365.
Full textVabbilisetty, Pratima. "Fabrication and Characterization of Substrate Materials for Trace Analytical Measurements by Surface Enhanced Raman Scattering (SERS) Spectroscopy Technique." Connect to resource online, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1231794465.
Full textAhmadi, Farzad. "Magnetic Micro- and Nanostructures for Electrical Machinery." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1544521347564228.
Full textBresson, Paul. "Étude des phénomènes thermiques ultrarapides dans les nanostructures plasmoniques." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST005.
Full textThermoplasmonics is a branch of plasmonics exploiting thermal phenomena in metallic structures. Long regarded as problematic, Joule losses due to the absorption of light by metallic nanoparticles are now considered as a starting point for many applications: thermal nanosources in medicine, magnetic recording, chemical catalysis, thermotronics or energy conversion.The use of femtosecond lasers on plasmonic structures, allows the creation of spatially confined nanosources of heat reaching very high electronic temperatures compared to the temperature of the atomic lattice. The absorption by a metal of a pulse of energy can be described in three main steps. Firstly, an absorption of photons by the electrons of the metal increases the electron energy on the scale of a hundred femtoseconds with electronic temperatures that can reach thousands of Kelvin, while the lattice temperature remains almost constant. Then, a second step, in which the electron-phonon interactions transmit the energy absorbed by the electrons to the grid, allowing the electrons and phonons to reach equilibrium. Finally, the energy is dissipated into the substrate surrounding the metal by thermal conduction.Many models exist in the literature to describe the non-equilibrium between electrons and phonons. However, a rigorous and quantitative comparison with experimental data is lacking to validate or invalidate these models. This was the main objective of this study.To study these phenomena, I used a pump-probe experiment where the pump allows an ultra-fast heating of the sample which causes a change in the permittivity of the metal. The probe beam then allows to measure the variations in the reflection and transmission spectrum, caused by the change in permittivity.I set up a numerical code allowing to model the temperature evolution in a 3D mesh of a structure composed of dielectric and metallic elements. This thermal model takes into account the various energy transport phenomena in a metal such as electron-phonon coupling, electron and phonon thermal conduction and ballistic displacement of non-thermalized electrons. Then, via a model of permittivity as a function of temperature taking into account the interband and intraband transitions, this model was coupled to an optical model to simulate the evolution of the optical spectra of a structure as a function of its temperature in order to be able to confront this numerical model with the experimental results by data fitting.This numerical model has been validated on numerous pump-probe experiments carried out on gold films of various thicknesses and gold nanostructure arrays on glass or gold film. We were able to show that, among the very large number of optical and thermal parameters involved in the model, all these experimental data could be adjusted using a very small number of free parameters, thus confirming the robustness of the model. Finally, this model was used to design and optimize samples allowing the experimental demonstration of heat propagation on scales of a few hundred nanometers within a gold nanostructure
Nick, Zachary H. "Foundations for Smart Metamaterials by Liquid Metal Digital Logic and Magnetoelastic Properties Control." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587669303938667.
Full textLoreto, Renan Pires. "Proposta para realização de correntes magnéticas em gelos de spin artificiais." Universidade Federal de Viçosa, 2014. http://locus.ufv.br/handle/123456789/4272.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Spin ice is a substance that does not have a single minimalenergy state. Even at very lower temperatures, these compounds shows a residual entropy as well as the water ice. The magnetic ordering of a spin ice resembles the position of hydrogen atoms in water ice, arranged in a tetrahedron and obeying the the ice rule. The most prominent ice spin compounds are holmium titanate and dysprosium titanate. This system is subject to geometrical frustration, when all interactions between pairs are not satisfied simultaneously. The artificial spin ice are structures that have magnetic monodomains subject to geometrical frustration generating mono pole antimonopole pairs (or magnetic charges ) connected by an observable string. As the flow of electrical charges produces electric current, magnetic monopoles that can walk freely generate something like a magnetic current in these frustrated systems. In this work we manufacture and characterize structures of artificial spin ice, produced by nanolithography techniques, arranged in a rectangular unidirectional lattice and characterized by Atomic Force Microscopy (AFM) and Magnetic Force Microscopy (MFM). We note that for this particular lattice, the experimental results of ground state are consistent with the theoretical results also presented in this dissertation. Thus, these systems of artificial spin ice are a proposal for a practical use of magnetic currents caused by application of an external magnetic field. This system can be used at room temperature and its parameters, as nanoislands size and lattice spacing can be turned at will.
Gelo de spin é uma substância que não possui um único estado de mínima energia. Mesmo a temperaturas muito baixas, esses compostos apresentam uma entropia residual, assim como no gelo da água. O ordenamento magnético de um gelo de spin se assemelha a posição dos átomos de hidrogênio no gelo da água, dispostas em um tetraedro e obedecendo a chamada regra do gelo. Os gelos de spin naturais mais comuns são compostos de titanato de hólmio e titanato de disprósio. Este sistema é sujeito à frustração geométrica, quando todas as interações entre pares não são satisfeitas simultaneamente. Os gelos de spin artificiais são estruturas que possuem monodomínios magnéticos sujeitos a frustração geométrica gerando pares monopoloantimonopolo (ou cargas magnéticas) ligados por uma string observável. Assim como o fluxo de cargas elétricas produz corrente elétrica, monopolos magnéticos podendo andar livremente, geram algo parecido com uma corrente magnética nesses sistemas frustrados. Neste trabalho fabricamos e caracterizamos estruturas de gelos de spin artificiais, produzidas por técnicas de nanolitografia, dispostas em uma rede retangular unidirecional e caracterizadas por Microscopia de Força Atômica (AFM) e Microscopia de Força Magnética (MFM). Observamos que para esta rede em particular, resultados experimentais do estado fundamental condizem com os resultados teóricos também apresentados neste trabalho. Assim, estes sistemas de gelos de spin artificiais são uma proposta para uma utilização prática de correntes magnéticas, causadas pela aplicação de um campo magnético externo. Este sistema pode ser utilizado a temperatura ambiente e seus parâmetros, como tamanho das nanoilhas e espaçamento de rede, podem ser ajustados a vontade.
Murdock, Richard Craig. "RADIO FREQUENCY CONTROLLED STIMULATION OF INTRACELLULAR GOLD OR SILVER NANOPARTICLE CONJUGATES FOR USE AS POTENTIAL SENSORS OR MODULATORS OF BIOLOGICAL FUNCTION." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1277753458.
Full textKamanalu, Sunil S. "Proximity and Thickness Estimation of Aluminum 3003 Alloy Metal Sheets Using Multi-Frequency Eddy Current Sensor." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1284513369.
Full textAmonson, Michael D. "Multiple Charge Carrier Species and Their Effects in Photorefractive Two-Beam Coupling in Potassium Niobate." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1512494096366019.
Full textYang, Yuan. "Influence of Chemical Doping on Microstructures and Superconducting Properties of MgB2 Wires and Bulk Samples." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469187563.
Full textLalley, Nicholas M. "Composite Electromagnetic Applications and Devices." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504878841254054.
Full textRaulet, Marie-Ange. "Contribution à la modélisation des matériaux magnétiques liés à leur environnement en génie électrique." Habilitation à diriger des recherches, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00703561.
Full textNing, Ding. "Analytical and Numerical Models of Multilayered Photonic Devices." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1207712683.
Full textSilva, Leonardo de Sousa. "Efeitos de diluição química no composto intermetálico GdIn3." Pós-Graduação em Física, 2013. https://ri.ufs.br/handle/riufs/5294.
Full textEste trabalho propôs a implementação da técnica de crescimento de monocristais via fluxo metálico, na Universidade Federal de Sergipe (UFS) campus de itabaiana. Além disso, o sistema YxGd1-xIn3 (0 < x < 0.5 a passo de 0.10 % ) foi obtido através dessa técnica e as propriedades estruturais e magnéticas foram estudadas. Medidas de difração de raios X foram realizadas com o intuito de verificar o crescimento da fase cristalina desejada. Os dados mostraram que ela foi obtida com sucesso. A caracterização magnética foi feita através de medidas de susceptibilidades magnética em função da temperatura (2 < x < 300 K) e do campo magnético (-7 < H < 7T). As medidas de magnetização em função da temperatura mostraram uma supressão da temperatura de ordenamento magnético com o aumento da concentração de ítrio. As análises desses dados mostraram que o sistema apresenta frustração magnética que está ligado ao efeito de diluição introduzido pelo íon de ítrio no sitio do gadolínio. As medidas de magnetização em função do campo magnético realizadas a 2 K mostraram um comportamento típico de um material com ordenamento antiferromagnético.
Venkatasubramanian, Rajiv. "Composite Nanoparticle Materials for Electromagnetics." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352993374.
Full textTörnqvist, Julia. "Electromagnetic Homogenization-simulations of Materials." Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-395866.
Full textChailloux, Thibaut. "Caractérisation et modélisation de matériaux magnétiques en hautes températures en vue d'une application au filtrage CEM." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00703562.
Full textSonde, Abayomi Emmanuel. "Etude et modélisation de procédés innovants de mise en compression de surfaces : Traitements de surface par cavitation et par impulsions électromagnétiques." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI015/document.
Full textSurface treatments methods like shot peening are used to introduce compressive residual stresses in metallic materials. The compressive stresses prevent the initiation and growth of cracks and hence improve the fatigue life of mechanical parts. The drawbacks and limitations of the existing processes generally used for this purpose are known and have been highlighted in many studies. These are, among others, an important surface modification (roughness), a limited compressive depth, difficulties in execution, debris and contamination problems, etc. Therefore, the interest in new surface treatment methods, which permit to obtain equivalent or even better compressive results while avoiding the previous problems, are growing. Cavitation peening and electromagnetic pulse peening are part of these innovative processes which modeling is the aim of this PhD thesis. Cavitation peening is a process of surface treatment which acts by the generation of cavitation bubbles near the workpiece surface. The modeling of this process is challenging because of the complexity of cavitation phenomenon and the main problematic point is the determination of the mechanical loading on the material due the bubbles collapse. In this thesis, an approach of modeling for cavitation peening based on the study of the dynamics of cavitation bubbles is proposed. Spherical and aspherical collapse of bubbles near a solid surface are studied by some numerical and analytical models. These two sources of loading pressures have been compared and a macroscopic model for cavitation peening have been derived by associating the numerical simulation of the cavitation jet and the localization of the cavitation zone. The comparison between the final residual stress profile calculated with the proposed model and the experimental results were satisfactory. Electromagnetic pulse peening (EMP) is a contactless process of surface treatment which could be used to introduce compressive residual stresses in conductive materials, by the generation of a high transient electromagnetic field. Laplace forces induced in the material by magnetic induction are the source of the material plastic deformation and compressive residual stresses introduction. To predict the EMP results, a numerical model have been built for the process simulation. The model, based on finite element method, coupled successfully electromagnetic and mechanical phenomena by using a sequential-coupled approach. It was proven theoretically, by the study of a reference case, that compressive residual stresses could be induced in metallic materials like nickel-based (Inconel) or aluminum alloys by the means of the present process. It was also shown by the calculations that much higher compressive depths than those of conventional peening processes could be achieved. The parametric study exhibited the influence of the maximum current intensity and frequency which affect both the compressive depth and the maximum residual stress
Magda, Geoffrey. "Study of metallic architected materials under mechanical and electromagnetic loads." Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAX138.
Full textRecent developments in the fields of meta-materials and magneto-mechanical couplings aim to both enhance existing properties and create new ones. The goal of this thesis is to study the interactions between magnetizable materials, electric currents, and mechanical response. First, we detail the multi-physics model required to address this issue. Whenever possible, an analytical solution is provided. To handle more complex geometries, a variational approach is employed for finite element analyses. Subsequently we examine two practical cases: a partially magnetizable mesh subjected to unidirectional currents and a partially magnetizable, conductive 2D composite. We investigate their behavior under combined magnetic and mechanical loading, as well as their stability
Chazottes-Leconte, Aurélien. "Conception et fabrication d'un dispositif de mise en compression par impulsions électro magnétiques (EMP)." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1082.
Full textPenning processes are widely used in industries to apply compressive residual stresses into the most solicited part of mechanical pieces. In that way, the compressive residual stresses limit the priming and the propagation of micro-cracks in the material. This increases significantly the lifespan of the treated mechanical piece under fatigue stresses. These existing peening processes have proved their efficiency and also their limitations and weaknesses. The main recurrent defaults are a shallow depth of treatment, a degradation of the surface condition, a random control of the treatment, a material contamination, etc. These problems have led towards the development of news innovative peening processes which allow better performance avoiding some previous defaults briefly evoked. Among these news processes, the electromagnetic peening process seems especially interesting. This process uses high energy electromagnetic fields to induce Lorentz forces into a metallic piece and thus residual stresses. Actually, there is not much information about this process in the literature and no prototype was ever built. The work of this thesis is dedicated to development and realization of an electromagnetic peening prototype. The first chapter of this thesis adresses the state of the art of major peening processes actually in industrial use. Next, the electromagnetic peening process, or EMP process, is described and the electrical needs are exposed. A second state of the art is made about the technological solutions to respond to the EMP needs. The second chapter is about the conception of the EMP prototype with the electrical structure adopted in the previous chapter. The first step is about the inductor sizing to generate an electromagnetic field sufficient enough for a peening application. Next, the storage system is designed depending on the inductor parameters and finally the closing switch is created considering the electrical parameters used for the EMP process. To validate the previous results, a 3D electromagnetic simulation is done. The prototype assembly is presented in the third chapter and also the first experimental test on the EMP prototype. To begin with, an aluminium alloy with low yield strength is selected to be treated. Two different samples forms are used, a thin one, to realize a similar test to the Almen test and thick one to check the EMP depth of treatment. A 3D multiphysics simulation of these experiments is made and these numeric results are next correlated to the experimental ones. In the fourth chapter, an exploratory study is realized on the effects of the residual stresses on magnetic properties of ferromagnetic material, the mumetal
CURRELI, NICOLA. "2D material-based electromagnetic devices." Doctoral thesis, Università degli Studi di Cagliari, 2020. http://hdl.handle.net/11584/284406.
Full textPenfold, Justin David John. "Controlled electromagnetic rewarming of cryopreserved biological materials." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319611.
Full textLu, Jie Ph D. Massachusetts Institute of Technology. "Novel electromagnetic radiation in Left-Handed materials." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/39566.
Full textIncludes bibliographical references (leaves 137-141).
In this thesis, Cerenkov radiation of a moving charged particle inside a Left-Handed material (LHM) is studied through both theory and numerical simulations. A LHM is a material whose permittivity and permeability have negative real parts. In the analysis of this thesis, the general theory of Cerenkov radiation was first studied for the unbounded regions filled with LHM. The physical meanings of different Green's functions are discussed, and finally the second kind of Hankel function is determined to represent the special properties of Cerenkov radiation: forward incoming phase and backward outgoing power, which satisfies both momentum and energy conservation. The effects of the dispersion and dissipation of both permittivity and permeability are also investigated. The results show that both forward and backward radiated waves can co-exist at different frequencies. When the dissipation is reduced, the directions of forward and backward radiation are close to 900 with respect to the particle's moving direction. When the LHM is bounded, a waveguide can be formed. Depending upon the configuration and the relative dielectric constants of the surrounding normal material (we call them RHM in comparison with LHM), a surface wave can be formed.
(cont.) When a LHM is used as the filling material of a metallic waveguide, the radiation at some frequencies can be enhanced when a surface wave is excited. This enhancement can make the total radiated power in the waveguide larger than the radiation when the LHM is unbounded. Furthermore, using the same surface wave property, the decay of the radiation by a free space channel can be compensated when the channel is surrounded by a LHM. The wave of Cerenkov radiation is a TM wave. In order to have a homogeneous response, the LHM structure should have at least two dimensional isotropic negative permittivity and one dimensional negative permeability. A new LHM design was proposed in this thesis. We have demonstrated that this design shows several advantages in comparison with present published designs through reflection and transmission simulations, and TM (TE) prism simulations. For the unit cell's dimension of 5mm, a LHM band is observed between 6GHz and 7GHz for TM wave incidence. We use an antenna array to model a traveling current source, which can represent a single frequency component of a particle motion. The simulations show that our design can bend the radiation inside the structure.
(cont.) In order to observe the signal in the far field, we propose to use prism shaped LHM structures around the antenna array, by which, the difference between the angles of the forward radiation and backward radiation can be further amplified. These results can be a basis for a future experimental verification of backward radiation of the antenna arrays in a LHM. Besides, two effects of the surface wave for the effective LHM slab are also investigated. The results show that the surface wave actually determines the focusing ability of a LHM slab. When the mismatch between the slab and the surrounding area becomes small, those evanescent waves, whose wave number is less than that of the surface wave, can be amplified by the slab, and contribute to the focusing at the image plane. This property can help us easily estimate the resolution of a LHM slab when it is used as a flat lens. A unique guided wave can also exist when a LHM slab is surrounded by two RHMs, where the two RHMs can be different or the same. This guided wave has a linear function for the transverse profile of the field inside the LHM slab, which can never exist in either a RHM or a plasma dielectric waveguide.
by Jie Lu.
Ph.D.
Ramesh, Prashanth. "Smart Materials for Electromagnetic and Optical Applications." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343821988.
Full textPressl, Daniel G. (Daniel Gerd). "Investigation of electromagnetic welding." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53253.
Full textCataloged from PDF version of thesis.
Includes bibliographical references.
We propose several methodologies to study and optimize the electromagnetic process for Electromagnetic Forming (EMF) and Welding (EMW), thereby lowering the necessary process energy up to a factor of three and lengthening the life-time of EMW compression coils. We present a new theoretical approach to calculate a so-called critical kinetic energy to achieve a proper EMW joint, which is related to the volume of the accelerated mass and the Vicker's Hardness of the material. Using this novel approach, welding windows for several materials are presented. Studying the circuit theory, the current discharge pulse can be optimized to the needs of the EMW process, when opting for a critically damped RLC circuit. We present MultiSIM and MATLAB models that prove the proposed optimization and reflect the experimental EMW setup and parameters. Using the models, unknown parameters, such as machine inductance and resistance can be extrapolated for EMF and EMW machinery. Furthermore, the MATLAB model can calculate the optimal gap between the outer and inner workpiece for the outer workpiece to reach the maximum velocity at impact. Good correlation was found with regards to the High-Speed Videography used to study the EMF process in further detail measuring velocities between 50 m/s and 100 m/s. Studying the mechanical properties of the outer workpiece we propose an EMF-EMW setup that would decrease the strength of the outer workpiece by introducing a controlled amount of wrinkles through an EMF step with a mandrel inside the outer workpiece, followed by a lower critical energy EMW step.
(cont.) Through a failure study, accompanied by a metallurgical analysis, of an Aluminum Bronze Bitter coil we present a materials selection of other possible coil materials, as well as a new method called Electromagnetic Fatigue (EMFA) Analysis to study the crack initiation and propagation in electromagnetic high-current applications. Finally, through two sets of EMW experiments tubular lap joints that were stronger than the base material could be produced and the EMW process parameters of increased cleanliness, gap, wall thickness and a lower taper angle, for the case of our setup, showed to increase the final joint strength.
by Daniel G. Pressl.
Ph.D.
Gollub, Jonah Nathan. "Characterizing artificial electromagnetic materials and their hybridization with fundamentally resonant magnetic materials." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3339169.
Full textTitle from first page of PDF file (viewed Feb. 6, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 109-115).
Figueiras, Fábio Gabriel Nazário. "Study of multiferroic materials." Doctoral thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/4271.
Full textThe present PhD work aims the research and development of materials that exhibit multiferroic properties, in particular having a significant interaction between ferromagnetism and ferroelectricity; either directly within an intrinsic single phase or by combining extrinsic materials, achieving the coupling of properties through mechanic phenomena of the respective magnetostriction and piezoelectricity. These hybrid properties will allow the cross modification of magnetic and electric polarization states by the application of cross external magnetic and/or electric fields, giving way to a vast area for scientific investigation and potential technological applications in a new generation of electronic devices, such as computer memories, signal processing, transducers, sensors, etc. Initial experimental work consisted in chemical synthesis of nano powders oxides by urea pyrolysis method: A series of ceramic bulk composites with potential multiferroic properties comprised: of LuMnO3 with La0.7Sr0.3MnO3 and BaTiO3 with La0.7Ba0.3MnO3; and a series based on the intrinsic multiferroic LuMn1-zO3 phase modified with of Manganese vacancies. The acquisition of a new magnetron RF sputtering deposition system, in the Physics Department of Aveiro University, contributed to the proposal of an analogous experimental study in multiferroic thin films and multilayer samples. Besides the operational debut of this equipment several technical upgrades were completed like: the design and construction of the heater electrical contacts; specific shutters and supports for the magnetrons and for the substrate holder and; the addition of mass flow controllers, which allowed the introduction of N2 or O2 active atmosphere in the chamber; and the addition of a second RF generator, enabling co-deposition of different targets. Base study of the deposition conditions and resulting thin films characteristics in different substrates was made from an extensive list of targets. Particular attention was given to thin film deposition of magnetic phases La1-xSrxMnO3, La1-xBaxMnO3 and Ni2+x-yMn1-xGa1+y alloy, from the respective targets: La0.7Sr0.3MnO3, La0.7Ba0.3MnO3; and NiGa with NiMn. Main structural characterization of samples was performed by conventional and high resolution X-Ray Diffraction (XRD); chemical composition was determined by Electron Dispersion Spectroscopy (EDS); magnetization measurements recur to a Vibrating Sample Magnetometer (VSM) prototype; and surface probing (SPM) using Magnetic-Force (MFM) and Piezo-Response (PFM) Microscopy. Results clearly show that the composite bulk samples (LuM+LSM and BTO+LBM) feat the intended quality objectives in terms of phase composition and purity, having spurious contents below 0.5 %. SEM images confirm compact grain packaging and size distribution around the 50 nm scale. Electric conductivity, magnetization intensity and magneto impedance spreading response are coherent with the relative amount of magnetic phase in the sample. The existence of coupling between the functional phases is confirmed by the Magnetoelectric effect measurements of the sample “78%LuM+22%LSM” reaching 300% of electric response for 1 T at 100 kHz; while in the “78%BTO+22%LBM” sample the structural transitions of the magnetic phase at ~350 K result in a inversion of ME coefficient the behavior. A functional Magneto-Resistance measurement system was assembled from the concept stage until the, development and operational status; it enabled to test samples from 77 to 350 K, under an applied magnetic field up to 1 Tesla with 360º horizontal rotation; this system was also designed to measure Hall effect and has the potential to be further upgraded. Under collaboration protocols established with national and international institutions, complementary courses and sample characterization studies were performed using Magneto-Resistance (MR), Magneto-Impedance (MZ) and Magneto-Electric (ME) measurements; Raman and X-ray Photoelectron Spectroscopy (XPS); SQUID and VSM magnetization; Scanning Electron Microscopy (SEM) and Rutherford Back Scattering (RBS); Scan Probe Microscopy (SPM) with Band Excitation Probe Spectroscopy (BEPS); Neutron Powder Diffraction (NPD) and Perturbed Angular Correlations (PAC). Additional collaboration in research projects outside the scope of multiferroic materials provided further experience in sample preparation and characterization techniques, namely VSM and XPS measurements were performed in cubane molecular complex compounds and enable to identify the oxidation state of the integrating cluster of Ru ions; also, XRD and EDS/SEM analysis of the acquired targets and substrates implied the devolution of some items not in conformity with the specifications. Direct cooperation with parallel research projects regarding multiferroic materials, enable the assess to supplementary samples, namely a preliminary series of nanopowder Y1-x-yCaxØyMn1O3 and of Eu0.8Y0.2MnO3, a series of micropowder composites of LuMnO3 with La0.625Sr0.375MnO3 and of BaTiO3 with hexagonal ferrites; mono and polycrystalline samples of Pr1-xCaxMnO3, La1-xSrxMnO3 and La1-xCaxMnO3.
O trabalho de doutoramento presente tem por objectivo a pesquisa e desenvolvimento de materiais que manifestem propriedades multiferróicas, em particular com uma significativa interacção entre os fenómenos de ferromagnetismo e ferroelectricidade; seja de forma intrínseca em determinados materiais singulares, ou extrínseca ao combinar materiais que apresentam respectivamente fenómenos magnetoestritivo e de piezoelectricidade e em que geralmente o acoplamento se processa mecanicamente entre as fases. Esta hibridação de propriedades permite a modificação dos estados de polarização magnética ou eléctrica por aplicação dos campos externos complementares (eléctricos e/ou magnéticos), dando origem a uma vasta área de investigação científica e potenciais aplicações tecnológicas numa nova geração de dispositivos electrónicos como memórias, processadores, transdutores, sensores, etc. O trabalho experimental inicial consistiu na síntese química de óxidos sob a forma de pós nanométricos, pelo método de pirólise da ureia; As séries de compósitos maciços com potenciais propriedades multiferróicas compreendem: LuMnO3 com La0.7Sr0.3MnO3 e BaTiO3 com La0.7Ba0.3MnO3; e uma série baseada na modificação com lacunas de Manganésio da fase multiferróica intrínseca LuMn1-zO3. A aquisição de um novo sistema de deposição por RF sputtering, no Departamento de Física da Universidade de Aveiro, contribuiu para a proposta de estudo análogo de amostras multiferróicas sob a forma de filmes finos e multicamadas. Além da estreia operacional do equipamento foram efectuadas algumas melhorias técnicas e funcionais de que se destacam: o desenho e construção das ligações eléctricas do aquecedor; de portadas, protecções e respectivos suportes para os magnetrões e para o “porta substratos”; a adição de dois controladores de fluxo de gás permitindo a introdução controlada de Árgon e de atmosfera activa de O2 ou N2 durante a deposição; e a adição de uma segunda fonte e controlador RF permitindo a co-deposição simultânea de filmes a partir de dois alvos diferentes. O estudo base sobre as condições de deposição e das características dos filmes finos resultantes em diferentes substratos foi efectuada a partir de uma extensa lista de alvos. Atenção particular foi dada à deposição de filmes finos das fases magnéticas de La1-xSrxMnO3, La1-xBaxMnO3 e da liga Ni2+x-yMn1-xGa1+y a partir dos correspondentes alvos La0.7Sr0.3MnO3; La0.7Ba0.3MnO3 e NiGa com NiMn. A caracterização estrutural das amostras foi efectuada com Difractometria por Raios-X (XRD) convencional e de elevada resolução; determinação da composição química foi essencialmente realizada por Espectroscopia de Dispersão de Electrões (EDS); medidas de magnetização foram executadas com recurso a um protótipo de Magnetometro por Vibração da Amostra (VSM) e as medidas de análise de superfície utilizaram Microscopia de Ponta (SPM) nas vertentes de piezo resposta (PFM) e de força magnética (MFM). Os resultados obtidos nos compósitos maciços (LuM+LSM e BTO+LBM) demonstram claramente que as amostras satisfazem os objectivos propostos em termos de composição pureza das fases, com eventual conteúdo em óxidos espúrios inferior a 0.5%. Imagens obtidas por SEM confirmam a compactação dos grãos e distribuição de tamanhos em torno dos 50 nm. Condutividade eléctrica, intensidade da magnetização e a dispersão da resposta em Magneto-Impedância são coerentes com a proporção relativa da fase magnética em cada amostra. A existência de um acoplamento entre as fases funcionais é evidenciada por medidas de efeito Magneto-Eléctrico na amostra “78%LuM+22%LSM” que apresenta uma resposta eléctrica de ~300% para 1 Tesla a 100 kHz; enquanto que na amostra “78%BTO+22%LBM” se assinala a transição estrutural da fase magnética a ~350 K resulta na inversão do comportamento do coeficiente ME. Um sistema de Medidas de Magneto-Resistência foi totalmente desenvolvido e montado desde a fase conceptual até ao estado operacional; permite testar amostras de 77 a 350 K em função do campo magnético até 1 Tesla, e rotação horizontal de 360º; o sistema foi também desenhado para poder efectuar medidas de efeito de Hall e permitir upgrades. Ao abrigo de protocolos de colaboração estabelecidos com diversas instituições nacionais e internacionais, foram realizados cursos de formação complementar e caracterização de amostras em técnicas como Magneto Resistência (MR), Magneto Impedância (MZ) e efeito Magneto Eléctrico (ME); Espectroscopia Raman e Fotoelectrónica de Raios-X (XPS); Magnetização via sistemas SQUID e VSM; Microscopia de Ponta em Piezo resposta (PFM) e Espectroscopia de excitação em largura de banda (BEPS); Espectroscopia de Rutherford por Retro dispersão (RBS); Difracção de Neutrões em pós (NPD) e Correlações de Perturbação Angular (PAC) Colaboração em projectos de investigação fora do âmbito dos materiais multiferróicos permitiu ampliar e versatilizar experiencia em técnicas de preparação e caracterização de amostras, nomeadamente medidas de VSM e XPS permitiram identificar os estados de oxidação dos clusters de iões de Ruténio que integram complexos moleculares utilizados em catalisadores; A certificação por XRD e SEM/EDS do conjunto dos alvos e amostragem dos substratos adquiridos implicou a devolução de alguns itens com por falta de conformidade com as especificações. Cooperação directa em projectos de investigação paralelos sobre materiais multiferróicos permitiu o acesso a amostras suplementares, nomeadamente a uma série nano pós de Y1-x-yCaxØyMn1O3 e de Eu0.8Y0.2MnO3; a series de compósitos microestruturados de LuMnO3 com La0.625Sr0.375MnO3 e de BaTiO3 com ferrites hexagonais; e a diversas amostras poli- e mono-cristalinas de Pr1-xCaxMnO3, La1-xSrxMnO3 e La1-xCaxMnO3.
FCT - SFRH/BD/25011/2005
Ruff, Bradley M. "Carbon Nanotube and Nanoparticle Materials for Electromagnetics Applications." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367925618.
Full textMurad, Mark Richard. "Radiation View Factors Between A Disk And The Interior Of A Class Of Axisymmetric Bodies Including Converging Diverging Rocket Nozzles." Cleveland State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1210962269.
Full textNaeem, Majid. "Theory, modelling, and applications of advanced electromagnetic materials." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/31858.
Full textHussaini, Sheena. "Integrated Magnetic Components for RF Applications." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1431951933.
Full textGupta, Bhaawan. "Advanced electromagnetic non-destructive testing on creep degraded high chromium ferritic steels : Characterization, Modelling and physical interpretation." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI074.
Full textUnder constant high temperatures and pressure, the material undergoes mechanical creep degradation which leads to microstructural changes. These microstructural changes if not monitored on time, can lead to some serious fatal accidents such as in power plants. To investigate these microstructural changes, the material has to be shaped in a certain specific shape and size to have the imaging analysis using Scanning electron microscopy, Electron backscatter diffract ion etc. which are destructive in nature and involve high equipment cost. In order to overcome this issue, this thesis work, incorporates three different non-destructive techniques, to study the evolution of magnetic signatures with respect to the level of rupture they are exposed to. It is legitimate to assume that all the microstructural changes that occur in the material can be reflected in the corresponding magnetic signatures measured. The material that has been studied here is high chromium creep degraded steel which is used in the thermal power plant. The magnetic signatures are evaluated in terms of microstructural information to draw the conclusions. Some magnetic parameters from the curves, such as coercivity, magnetic reversibility are derived which show strong correlations with the microstructure. Similarly, techniques based on Hysteresis curves, and magnetic Barkhausen Noise are also implemented. To further quantify the results obtained from the magnetic signatures of the materials, a model has been developed to derive model parameters in order to physically interpret the microstructural changes. The modelling technique will help in overcoming the issue of lack of standards in NDT, irrespective of the experimental set-up involved. The parameters are compared to reveal sensitivity based on the technique. Finally, conclusion has been drawn to check which parameters are correlated to microstructure for a particular NDT technique used
Rafiq, Muhammad Nadeem. "Carbon Microfiber Material for Electromagnetic (Shielding) Applications." Diss., North Dakota State University, 2015. http://hdl.handle.net/10365/25293.
Full textCOMSATS Institute of Information Technology, Pakistan
North Dakota State University (NDSU)
Sen, Saffet Gokcen. "Investigation Of Electromagnetic Wave Propagation In Double Negative Materials." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609748/index.pdf.
Full textAbram, Eric Ryan. "Electromagnetic materials characterization of ferromagnetic composites at microwave frequencies." [Ames, Iowa : Iowa State University], 2007.
Find full textMackay, Tom G. "Homogenisation of linear electromagnetic materials : theoretical and numerical studies." Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368749.
Full textYoungs, Ian John. "Electrical percolation and the design of functional electromagnetic materials." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271628.
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