Tesis sobre el tema "Electric properties tomography"
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DeGeorge, Vincent G. "Chemical Partitioning and Resultant Effects on Structure and Electrical Properties in Co-Containing Magnetic Amorphous Nanocomposites for Electric Motors". Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/885.
Texto completoHenry-Poulter, Siobhan. "An investigation of transport properties in natural soils using electrical resistance tomography". Thesis, Lancaster University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389933.
Texto completoWeigand, Maximilian [Verfasser]. "Monitoring structural and physiological properties of crop roots using spectral electrical impedance tomography / Maximilian Weigand". Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/1139048988/34.
Texto completoSlater, Lee David. "An investigation of the ability of cross-borehole electrical imaging to assist in the characterisation of hydrogeological properties at the field scale". Thesis, Lancaster University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360648.
Texto completoCadiou, François. "Étude de l'impact de la microstructure sur les propriétés effectives électriques des batteries lithium-ion". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI108.
Texto completoLi-ion batteries are interesting for applications such as electric vehicles. They have indeed a high energy and power density, which makes them good substitutes for internal combustion engines. However, even if they are now quite widely used in many fields, there is still a need to optimize their performance. This requires a better understanding of the impact of the electrodes microstructure on their effective properties to narrow the gap between ideal and practical performance. Three-dimensional characteristics such as the carbon additive percolation or the tortuosity of the porosity have a strong impact on the electrode charge transport properties and power performance. The use of 3D imaging techniques such as X-ray tomography and serial focused ion beam and SEM tomography (FIB/SEM) is very powerful to quantify the electrode microstructures and interpret their charge transport properties. Furthermore, by processing the reconstructed volumes, one can use them as a basis for numerical simulations. We have chosen the FFT (Fast Fourrier Transform) method with "discrete" Green operator for numerical computations. These simulations can either be used to back calculate the phase (active material or conducting additive/binder) conduction properties from macroscopic electrical measurements by inverse method, or to predict the electrode effective conductivity from the phase conductivities. The 3D numerical microstructures obtained can also be modified in order to predict the influence of compositional changes in the electrode formulation on its properties. This study sets new tools to understand better the relationships between microstructure, effective electrical properties and the performance of Li-ion battery composite electrodes
Hwang, Junyeon Kaufman M. J. "Characterization and mechanical properties of nanoscale precipitates in modified Al-Si-Cu alloys using transmission electron microscopy and 3D atom probe tomography". [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3661.
Texto completoHwang, Junyeon. "Characterization and Mechanical Properties of Nanoscale Precipitates in Modified Al-Si-Cu Alloys Using Transmission Electron Microscopy and 3D Atom Probe Tomography". Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3661/.
Texto completoTammas-Williams, Samuel. "XCT analysis of the defect distribution and its effect on the static and dynamic mechanical properties in Ti-6Al-4V components manufactured by electron beam additive manufacture". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/xct-analysis-of-the-defect-distribution-and-its-effect-on-the-static-and-dynamic-mechanical-properties-in-ti6al4v-components-manufactured-by-electron-beam-additive-manufacture(cb034391-b61f-4e16-91cd-7ad3c9ec6312).html.
Texto completoChelaghma, Saber Ayoub. "Fonctionnalisation de composites C/PEKK pour application aérospatiale : caractérisation, modélisation et influence sur les propriétés du composite". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30362.
Texto completoReducing aircraft weight is one of the major challenges facing the aerospace industry. In order to achieve the ambitious goals of fuel consumption and emission reduction, carbon-fiber reinforced composites have been introduced to the market. These materials are attracting increasing interest, however, they have low electrical conductivity to ensure protection against lightning strike. For this reason, composites filled with conductive particles are the subject of ongoing research activities. The objective is the development of multifunctional composites with enhanced electrical properties. Actually, the most used thermoplastic matrix is PEEK, but this polymer remains expensive, and its processing temperature is high. For this purpose, thermoplastic matrices, such as PEKK, are again studied. Between the raw material and the final part, the thermoplastic matrix undergoes several thermal steps with high temperature exposure (impregnation, consolidation, forming and assembly processes) during which its ability to crystallize evolves continuously. In order to evaluate the impact of the process and the composite constituents on its properties, crystallization has been the subject of particular attention. Two complementary experimental devices were used to characterize the crystallization. The heating stage, allows to apply a thermal cycle and observe the crystallization in optical microscopy and differential scanning calorimetry. The influence of carbon fibers and conductive fillers on the crystallization kinetics was evaluated. A decrease in crystallization times was observed through the increase of the nucleation rate. The collected data were used to develop a kinetic model identified through an original approach based on microscopic data. This model makes it possible to predict the crystallization kinetics of PEKK composites. Nevertheless, it does not make it possible to predict the final microstructure. However, the microstructure has a significant impact on mechanical properties as it has been proven through nano-indentation tests. To predict the final microstructure, a model based on the pixel coloring approach has been developed. The influence of carbon fibers has been introduced through the formation of a transcrystalline phase. A good correlation is found between the analytical approach, the simulation and the experimental data in terms of crystallization kinetics. Mechanical and electrical characterizations were performed to evaluate the performance of these new materials. On the studied materials, the mechanical response is not homogeneous as observed on tensile tests followed in stereo-correlation. The study of matter health shows the existence of defects, in particular, at the microstructure level. In order to take this particularity into account, it is thus necessary to describe the microstructure more finely. For this, X-ray tomography was used to characterize the composite. Recent developments in this technique allow, in combination with segmentation tools, to reconstruct a representative geometry of the material. This geometry is used to simulate the mechanical behaviour as well as the crystallization. The numerical simulations of an RVE are able to calculate the properties of a ply, then those of a laminate. This multi-scale modelling could reduce the number and cost of experimental campaigns. Thus, determining the properties of the final structure based on characterizations and simulation at the microstructure scale is a strategic scientific and industrial issue. This work is a contribution towards this approach
Perret, Anouk. "Méthodologie de caractérisation microstructurale 3D de matériaux poreux structurés pour la thermique". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0042/document.
Texto completoThe national objectives on the reduction of the rejections of greenhouse gases bring to the necessity of a thermal renovation for 75 % of the French buildings. As the requirements for old and new buildings increase their standards, design thinner and more efficient insulation materials is of great and increasing interest. New insulating materials with thermal conductivities lower than the still dry air (25 mW / (m. K)), such as based silica xerogel products (15 mW / ( m.K )), recently developed, are an interesting choice to answer those new fonctionnalities. In our study, silica xerogels (porosity > 80 %, specific surface > 600 m ²/g) are available as granular materials and binded stiff composite boards (xerogels / latex). The optimization of these materials requires to understand the link between their microstructure, their thermal conductivity and their mechanical behaviour
Tsivoulas, Dimitrios. "Effects of combined Zr and Mn additions on the microstructure and properties of AA2198 sheet". Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/effects-of-combined-zr-and-mn-additions-on-the-microstructure-and-properties-of-aa2198-sheet(6bb2c9db-7584-464b-8064-bab0cc2d397c).html.
Texto completoARATA, ANELYSE. "Degradação a baixa temperatura da Y-TZP odontológica: análise microestrutural e avaliação das propriedades mecânicas". reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27129.
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O objetivo deste estudo foi a Y-TZP odontológica submetida ao envelhecimento hidrotérmico acelerado (EH). Especificamente: a) determinar a curva cinética de transformação de fase tetragonal para monoclínica; b) calcular a velocidade de crescimento da frente da camada transformada durante o EH; c) avaliar a relação entre a porcentagem de fase monoclínica e profundidade da transformação de fase com a resistência à flexão biaxial (FB); d) avaliar o efeito da associação do EH e fadiga na resistência à FB. Discos sinterizados (YZ- Vita YZ, LP-Lava Plus) foram submetidos ao EH a 120°C, 130°C e 150°C e analisados por difração de raios X (DRX). Uma amostra por grupo foi analisada por microscopia eletrônica de varredura (MEV) e tomografia de coerência óptica (OCT) para calcular a profundidade de transformação de fase e a velocidade da frente de transformação. Grupos de (YZ, LP e LA-Lava) foram submetidos ao EH (150°C) por (n=10): 0, 5, 25, 70 e 140 horas. Após o EH os grupos de YZ foram novamente divididos (n=10): com e sem ciclagem mecânica, todas as cerâmicas foram submetidas ao teste de flexão biaxial (ISO 6872) e análise de variância 1 fator (ANOVA) (α=0,05) para comparar os resultados. Os resultados de DRX indicam que a Y-TZP apresenta um comportamento sigmoidal de transformação de fase devido à limitação da profundidade de penetração dos raios X (~6,3 μm). As análises de MEV e OCT confirmaram o crescimento linear da frente de envelhecimento em função do tempo para todas as temperaturas. O ANOVA 1-fator demonstrou redução de 10-19% da resistência à FB após 140 horas de envelhecimento (150°C) para todas as cerâmicas, havendo correlação negativa entre profundidade da camada transformada e resistência à FB. Extrapolando os resultados de profundidade para 37°C foi calculado que a frente de transformação de fase levaria 1053 e 2104 anos para atingir a profundidade de 62,67μm e 85,55μm responsáveis pela diminuição da resistência mecânica da YZ e LP, respectivamente. A associação do EH com a ciclagem mecânica não apresentou efeitos deletérios para a YZ. O OCT foi validado como método preciso, fácil e rápido para avaliação da camada transformada e estudos de cinética.
Tese (Doutorado em Tecnologia Nuclear )
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
Baimpas, Nikolaos. "'Hybrid' non-destructive imaging techniques for engineering materials applications". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:1aa00fed-34e6-4a5e-951b-c710e21ac23c.
Texto completoFinco, Cécile. "Étude de l’impact simultané des propriétés électriques, diélectriques et magnétiques du sous-sol sur la mesure géophysique par méthode électromagnétique inductive dans le domaine temporel (TDEM)". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS103.
Texto completoThe geophysical electromagnetic inductive method in the time domain (TDEM) is used in fields such as hydrology or in mining exploration. It allows the establishment of electrical resistivity models of the subsurface. Using this methods with reduced acquisition loops with a width of only a few meters, makes the measurement more sensitive to additional parameters : the dielectric permittivity and the magnetic permeability. The present research work aims to acquire a small-loop TDEM sounding and to extract not only an electical resistivity model but also an estimation of the dielctric permittivity and of the magnetic viscosity. The acquisition of a small-loop TDEM sounding implies a increased sensitivity to the response from the acquisition system itself, in part because of the reduced distance between the transmission and reception loops. Simulations aiming to reproduce this system response have been carried out to be able to take it into account during the data processing step. A specific acquisition geometry is then proposed to ease the multi-parameter interpretation of the TDEM data. The effects from the electric, dielectric and magnetic properties of the ground are overlapping on the measurements in the central configuration. Using different geometry with lower sensivities to dielectric permittivity and magnetic viscosity should make the contribution of each parameter easier to isolate. These methological developments were then tested with field measurement on the test site of Garchy (Nièvre, France)
Simancas, Coloma Jorge. "Synthesis and Characterization of Zeolitic Materials Using Phosphorous Organic Structure Directing Agents". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/171267.
Texto completo[CA] Les zeolites són materials cristal·lins microporosos amb canals i mides de porus de dimensions moleculars. L'estructura i composició de les zeolites els confereix interessants propietats que permeten la seua aplicació en una àmplia gamma d'aplicacions industrials com adsorció, separació o catàlisi. La síntesi de zeolites és l'etapa més important per al control de l'estructura i composició de les zeolites i, per tant, crítica per a l'optimització de les seues propietats. Aquesta tesi s'ha centrat en la síntesi de zeolites utilitzant compostos que contenen fòsfor (cations fosfoni i aminofosfoni) com a agents directors d'estructura (P-ADE). L'ús de compostos fosforats influeix en la cristal·lització i propietats de les zeolites obtingudes en comparació amb les zeolites obtingudes amb cations d'amoni clàssics. Els compostos fosforats es van triar a causa de la seua diferent química i estabilitat pel que fa als cations d'amoni clàssics utilitzats en la síntesi de zeolites. Aquests aspectes s¿estudiaren amb un estudi comparatiu de diferents cations d'amoni i fosforats. Els compostos de fòsfor utilitzats en aquest treball han donat lloc a noves estructures cristal·lines (ITQ-58 i ITQ-66) i han obert noves vies de síntesi de zeolites ja conegudes (RTH, IWV i DO), ampliant la seua gamma de composicions químiques. La descomposició tèrmica dels P-ADE atrapats dins de les zeolites dona lloc a la for-mació d'espècies de fòsfor extra-xarxa que romanen dins dels canals i cavitats de les zeolites. Aquestes espècies modulen les propietats àcides i d'adsorció dels materials finals depenent dels tractaments post-síntesi. En aquest treball s'ha estudiat una ruta per la incorporació de quantitats controlades de fòsfor durant l'etapa de síntesi. Això ha permés controlar l'adsorció i les propietats àcides en les zeolites de porus petit, el que no es pot aconseguir mitjançant metodologies de post-síntesi.
[EN] Zeolites are microporous crystalline materials with channels and pore openings of molecular dimensions. The structure and composition of zeolites confers them interesting properties that allow their application in a wide range of industrial applications as adsorption, separation or catalysis. The synthesis of zeolites is the most important stage to control the structure and composition of zeolites, and thus, critical to optimize their properties. This thesis has been focused on the synthesis of zeolites using phosphorous containing compounds (phosphonium and aminophosphonium cations) as Organic Structure Directing Agents (P-OSDA). The use of these phosphorous compounds influence the crystallization and properties of the obtained zeolites compared to zeolites obtained with classical ammo-nium cations. Phosphorous compounds were chosen because of their different chemistry and stabil-ity properties respect to classical ammonium cations commonly used in the synthesis of zeo-lites. These aspects were studied in a comparative study with different ammonium and phosphorous cations. The phosphorous compounds used in this work have yielded new crystalline structures (ITQ-58 and ITQ-66) and opened new routes for the synthesis of already known zeolites (RTH, IWV and DON), widening their chemical composition range. The thermal decomposition of the P-OSDAs entrapped inside the zeolites yields to the formation of extra-framework phosphorus species that remain inside the channels and voids of the zeolites. These species modulate the adsorption and acid properties of the final materials depending on the post-synthesis treatments. In this work, a route for the incorporation of controlled amounts of phosphorus during the synthesis stage has been studied. This has allowed to control the adsorption and acid properties in small pores zeolites, which cannot be achieved by post-synthesis methodologies.
I wish to firstly acknowledge the Spanish Government for the necessary funding for the FPI pre-doctoral fellowship (BES-2013-062999). Also, this thesis would not have been possible without the infrastructures provided by the UPV and the CSIC staff, fused into the ITQ. Furthermore, I want to acknowledge the Microscopy Service of the UPV for their support in sample microscopy characterization
Simancas Coloma, J. (2021). Synthesis and Characterization of Zeolitic Materials Using Phosphorous Organic Structure Directing Agents [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171267
TESIS
Huq, Ragibul. "Development of a novel sensor for soot deposition measurement in a diesel particulate filter using electrical capacitance tomography". Thesis, 2014. http://hdl.handle.net/1805/5929.
Texto completoThis paper presents a novel approach of particulate material (soot) measurement in a Diesel particulate filter using Electrical Capacitance Tomography. Modern Diesel Engines are equipped with Diesel Particulate Filters (DPF), as well as on-board technologies to evaluate the status of DPF because complete knowledge of DPF soot loading is very critical for robust efficient operation of the engine exhaust after treatment system. Emission regulations imposed upon all internal combustion engines including Diesel engines on gaseous as well as particulates (soot) emissions by Environment Regulatory Agencies. In course of time, soot will be deposited inside the DPFs which tend to clog the filter and hence generate a back pressure in the exhaust system, negatively impacting the fuel efficiency. To remove the soot build-up, regeneration of the DPF must be done as an engine exhaust after treatment process at pre-determined time intervals. Passive regeneration use exhaust heat and catalyst to burn the deposited soot but active regeneration use external energy in such as injection of diesel into an upstream DOC to burn the soot. Since the regeneration process consume fuel, a robust and efficient operation based on accurate knowledge of the particulate matter deposit (or soot load)becomes essential in order to keep the fuel consumption at a minimum. In this paper, we propose a sensing method for a DPF that can accurately measure in-situ soot load using Electrical Capacitance Tomography (ECT). Simulation results show that the proposed method offers an effective way to accurately estimate the soot load in DPF. The proposed method is expected to have a profound impact in improving overall PM filtering efficiency (and thereby fuel efficiency), and durability of a Diesel Particulate Filter (DPF) through appropriate closed loop regeneration operation.
Selvakumaran, Lakshmi. "On micro to mesoscale homogenization of electrical properties for damaged laminated composites (and their potential applications in electrical tomography)". Diss., 2015. http://hdl.handle.net/10754/592653.
Texto completoShariq, Ahmed. "Short range ordering and microstructure property relationship in amorphous alloys". Doctoral thesis, 2007. http://hdl.handle.net/11858/00-1735-0000-0006-B44C-D.
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