Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016. / Tomography is the ability to internally visualise an opaque medium or a body, using different imaging techniques. Electrical Resistance Tomography (ERT) technique is a method commonly used in process tomography. It uses a non-intrusive resistance measurement between a set of electrodes attached on the circumference of a fixed cross-section with a given conductivity and permittivity distribution. ERT appears to be simple, low cost, safe and non-invasive. Despite the advantages of ERT, the reconstruction of the internal conductivity of the pipe still face a crucial challenges such as noise, a relatively low spatial resolution, as well as ill-posedness of the inverse problem when doing the image reconstruction using reconstruction algorithms. Although previous work showed the potential of various algorithms for the reconstruction of ERT tomograms, no full characterisation and comparison of different algorithms could be found for real flow situations. The ERT system was tested in the identification of different objects and fluid beds in a real time situation. The data collected from the measurements were then used for the image reconstruction using an algorithm developed by Time Long (One-step algorithm) and four EIDORS-based algorithms namely: Gauss-Newton algorithm with Laplace Prior (LP) and Gaussian prior (Automatic Hyper Parameter Selection (AHSP)), the Total Variation (TV) algorithm and the Conjugate Gradient (CG) algorithm. The performance of each algorithm was tested in different scenarios. The results obtained were then compared based on the quality and the accuracy of the images as well as the computational time of each algorithm. Firstly, reconstructed images were obtained using objects placed inside the ERT pipe test. Secondly, the algorithm performances were put to test in a level bed setup experiment and finally, the algorithm reconstructions were applied to the real flow situation, where different flow rates were applied. The results obtained were then analysed and compared.

Resumo: A doença hepática crônica influencia direta e indiretamente o estado nutricional do paciente, sendo a desnutrição bastante prevalente nesta população. As causas da desnutrição são multifatoriais, relacionadas à alteração na ingestão, na absorção e no metabolismo dos macro e micronutrientes. O diagnóstico nutricional torna-se difícil, pois, não existe um método considerado padrão-ouro e os métodos disponíveis podem não ser fidedignos pela influência da própria doença no resultado. O objetivo do trabalho foi avaliar os indicadores do estado nutricional e a composição corporal dos pacientes portadores de cirrose hepática e relacioná-los com o sexo, a etiologia e a gravidade da doença hepática. Os indicadores nutricionais avaliados foram os antropométricos (Índice de Massa Corpórea específico para pacientes cirróticos, dobras cutâneas e circunferências), os funcionais (dinamometria e espessura do músculo adutor do polegar), a avaliação nutricional subjetiva global e os laboratoriais (albumina, hemoglobina, hematócrito e contagem total de linfócitos). Para a avaliação da composição corporal foi utilizada a bioimpedância elétrica unifrequencial (BIA) que mensurou a resistência (R), a reactância (Xc), o ângulo de fase (AF) e a massa celular corpórea (MCC). A gravidade da doença hepática foi estimada pelos critérios de Child-Pugh e pelo Meld (The model end-stage liver disease). Os indicadores do estado nutricional foram dicotomisados em: desnutrição e sem desnutrição ou com depleção e sem depleção. Os pacientes cirróticos de etiologia alcoólica apresentaram maior depleção em todos os parâmetros antropométricos, funcionais e na avaliação nutricional subjetiva global (ANSG), sendo estatisticamente significante para Circunferência do Braço (CB), Circunferência Muscular do Braço (CMB) e ANSG... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The chronic hepatic disease directly and indirectly influences on patient's nutritional status and malnutrition is highly prevalent in this population. The causes of malnutrition are multifactorial, related to alterations on ingestion, absorption and metabolism of macro and micronutrients. The nutritional diagnosis is difficult, because there isn't a gold standard method, and available methods are not reliable, once the disease itself interferes in the result. The objective of the work was to appraise nutritional status indicators and body composition of cirrhotic patients treated in the nutrition first aid posts of Faculdade de Medicina de Botucatu - UNESP, and relate them to gender, etiology and severity of the liver disease. The nutritional indicators appraised have been the anthropometrical (specific body mass index for cirrhotic patients, skinfolds and circumferences), the functional (dynamometry and thickness of the adductor pollicis muscles), the Subjective Global Assessment of Nutritional Status (SGA) and the laboratorial (albumin, hemoglobin, hematocrit, lymphocytes total count). On the appraisement of body composition, unifrequency bioelectrical impedance analysis (BIA) has measured resistance (R), reactance (Xc), phase angle (PA) and body cell mass (BCM). The severity of the liver disease has been estimated by the Child-Pugh score and by Meld (The Model end-stage liver disease). The nutritional status indicators have been dichotomized as following: malnutrition and without malnutrition, or with depletion and without depletion. Cirrhotic patients with alcoholic etiology have exhibited more depletion in all the anthropometrical and functional parameters and in the Subjective Global Assessment of Nutritional Status (SGA) and they have been statistically relevant for Arm Circumference (AC), Arm Muscular Circumference (AMC) and SGA... (Complete abstract click electronic access below) / Orientador: Alexandre Bakonyi Neto / Coorientador: Maria Antonieta de Barros Leite Carvalhaes / Coorientador: Giovanni Faria Silva / Banca: Maria Rita Marques de Oliveira / Banca: Milena da Costa Meneses Comacini / Mestre

Orientador: Ervino Carlos Ziemath / Banca: Lygia Christina de Moura Walmsley / Banca: Ana Candida Martins Rodrigues / Resumo: Neste trabalho foi avaliada a condutividade elétrica de vidros com composição (mol%) 22Na2O·8CaO·65SiO2·5MO2, com M = Si, Ti, Ge, Zr, Sn e Ce, sem e com troca iônica Ag+↔Na+ em 350 ºC por 1 hora. Após a troca iônica, amostras também foram submetidas a tratamento térmico em 500 ºC durante 24 horas. As medidas elétricas foram realizadas com um analisador de impedâncias Solartron. Foram analisados gráficos de Z" vs. Z' e de σ' vs. f em função da temperatura com o objetivo de se determinar, de duas maneiras diferentes, as energias de ativação para a condutividade elétrica, Eσ. Os valores das resistências elétricas das amostras são obtidos a partir de gráficos Z" vs. Z' quando Z" se anula para baixas frequências. Conhecendo-se o parâmetro geométrico da amostra, calcula-se a condutividade para corrente contínua, σdc. Através das curvas σ' vs. f determina-se σdc quando f → 0. Gráficos de Ln σdc vs. T-1 possibilitaram determinar 0,724 < Eσ < 0,826 eV, valores que concordam com os encontrados na literatura. Após submetidas à troca iônica, as amostras apresentaram aumento da condutividade. Por outro lado, o tratamento térmico posterior diminui a condutividade da maioria das amostras, provavelmente, devido à formação de nanopartículas de prata metálica na matriz vítrea. Para verificar alterações da composição devido à troca iônica e ao tratamento térmico utilizamos a técnica de espectroscopia de energia dispersiva de raios-X, EDS, no volume e na superfície das amostras. Verificou-se que a Ag migra para o volume durante o tratamento térmico, tendendo a tornar constante a sua distribuição, dependendo do cátion tetravalente, M4+, presente na matriz vítrea. A espectroscopia de reflexão difusa no infravermelho, DRIFT, indicou alterações na estrutura da superfície das... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work, it has been evaluated the electrical conductivity of glasses with composition (mol%) 22Na2O·8CaO·65SiO2·5MO2, with M = Si, Ti, Ge, Zr, Sn and Ce, without and with ion exchange Ag+↔Na+ at 350 ºC for 1 hour. After the ion exchange, samples were also submitted to thermal treatment at 500 ºC for about 24 hours. Electrical measurements were carried out with a Solartron impedance analyzer. Z" vs. Z' and σ' vs. f plots were analyzed as a function of temperature in order to determine, by two distinct approaches, the activation energies for the electrical conductivity, Eσ. The values of the electrical resistances of the samples are obtained from Z" vs. Z' plots when Z" nulls itself at low frequencies, and knowing the geometric parameter of the sample, the continuous current conductivity, σdc, can then be calculated. Through σ' vs. f plots, one can determine σdc when f → 0. We were able to determine 0,724 < Eσ < 0,826 eV by Ln σdc vs. T-1 plots, and those values agree with the ones found in the literature. When submitted to ion exchange, the samples showed an increased conductivity. On the other hand, a subsequent thermal treatment diminishes the conductivity for most of the samples, probably due to the formation of metallic silver nanoparticles in the vitreous matrix. In order to check for compositional modifications due to the ion exchange and thermal treatment, we have employed the energy dispersive X-ray spectroscopy technique, EDS, in the bulk and surface of the samples. It has been observed that Ag migrates towards the bulk during the thermal treatment, tending to reach a constant distribution, depending on the tetravalent cation, M4+, in the vitreous matrix. The diffuse reflectance infrared Fourier transform, DRIFT, have pointed changes in the surface structure of the samples... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:30:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-20Bitstream added on 2014-06-13T21:00:48Z : No. of bitstreams: 1 nunesneto_o_me_bauru.pdf: 1131438 bytes, checksum: 09b76ed29dfc8f7b3da8ade09c2b1487 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Efeitos de campo magnético em materiais e dispositivos orgânicos não-magnéticos vêm sendo foco de grande destaque na comunidade científica. De maneira a melhor compreender tais fenômenos, este trabalho propôs-se à implementação das técnicas de Espectroscopia de impedância elétrica em correntes alternadad (EIE-AC) na Presença de Campo Magnético e de Ressonância Magnética Detectada Eletricamente (RMDE). Para a montagem dessas técnicas foram utilizados instrumentos convencionais disponiveis no laboratório e as suas arquiteturas foram planejadas para permitir a utilização desses instrumentos em outros sistemas de medida. Programas na plataforma Agilent Vee Pro 9.2 foram desenvolvidos para o controle e aquisição dos dados das medições. A validação do sistema de EIE-AC na Presença de Campo Magnético foi efetuada a partir de medidas em circuitos básicos e num diodo orgânico emissor de luz (OLED) à base da molécula de Alq3, o qual era sabido que este apresentava o efeito de magnetoresistência. A influência do campo magnético sobre o comportamento das impedâncias do OLED de medida só foi percebida significativamente a partir da aplicação de tensões contínuas acima de 4 V, as quais condicionavam o OLED em seu estado emissivo. O fenômeno de Magneto-Impedância foi verificado nessa amostra, sendo que os efeitos mais expressivos ocorreram nas impedâncias imaginárias e para a frequencia em torno de 20Hz. Um segundo efeito de campo magnético de longo prazo de ação sobre o comportamento da impedância da amostra também foi verificado e discutido. Dentre os mecanismos físicos que podem explicar os efeitos observados no OLED, destacam-se os processos de recombinação de carga, o aprisionamento de cargas em defeitos e a ocorrência de polarização magnética das moléculas constituintes do OLED / Magnetic Field Effects on non-magnetic organic materials and device have attracted the attention of the scientific community. In order to elucidate those phenomena, this work proposes the implantation of two advanced characterization techniques: Electrical Impedance Spectroscopy in Alternating Current (EIS-AC) in the presence of magnetic field; and electrically detected magnetic resonance (EDMR). Both techniques were implemented using conventional laboratory instruments. Computational routiness were developed with Agilent Vee Pro 9.2 in order to control and acquire data from the measuring instruments. the validation f eIS-AC system was performed by using basic electrical circuits and an Organic Light Emiting Diode (OLED) based in Alq3 molecule, which has the magnetoresistance effect. The magnetic field effects over impedances were only detected when the applied continuous voltage was above 4 V, from which the OLED is in its emiting state. The Magneto-Impedance phenomenon was evidenced in this sample mainly in the imaginary impedances and for frequencies around 20 Hz. A second magnetic field effect, with long time term action over the impedance behavior, was also verified and discussed. Among the possible physical mechanisms behind the magnetic effects, charge recombination process, charge trapping by deffects, and the magnetic polarization of the OLED active molecules are discussed

abstract: In this dissertation a new wideband circular HIS is proposed. The circular periodicity made it possible to illuminate the surface with a cylindrical TEMz wave and; a novel technique is utilized to make it wideband. Two models are developed to analyze the reflection characteristics of the proposed HIS. The circularly symmetric high impedance surface is used as a ground plane for the design of a low-profile loop and spiral radiating elements. It is shown that a HIS with circular periodicity provides a wider operational bandwidth for curvilinear radiating elements such, such as loops and spirals, compared to canonical rectangular HISs. It is also observed that, with the aid of a circular HIS ground plane the gain of a loop and a spiral increases compared to when a perfect magnetic conductor (PMC) or rectangular HIS is used as a ground plane. The circular HIS was fabricated and the loop and spiral elements were placed individually in close proximity to it. Also, due to the growing demand for low-radar signature (RCS) antennas for advanced airborne vehicles, curved and flexible HIS ground planes, which meet both the aerodynamic and low RCS requirements, have recently become popular candidates within the antenna and microwave technology. This encouraged us, to propose a spherical HIS where a 2-D curvature is introduced to the previously designed flat HIS. The major problem associated with spherical HIS is the impact of the curvature on its reflection properties. After characterization of the flat circular HIS, which is addressed in the first part of this dissertation, a spherical curvature is introduced to the flat circular HIS and its impact on the reflection properties was examined when it was illuminated with the same cylindrical TEMz wave. The same technique, as for the flat HIS ground plane, is utilized to make the spherical HIS wideband. A loop and spiral element were placed in the vicinity of the curved HIS and their performanceswere investigated. The HISs were also fabricated and measurements were conducted to verify the simulations. An excellent agreement was observed. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018

abstract: As robotic systems are used in increasingly diverse applications, the interaction of humans and robots has become an important area of research. In many of the applications of physical human robot interaction (pHRI), the robot and the human can be seen as cooperating to complete a task with some object of interest. Often these applications are in unstructured environments where many paths can accomplish the goal. This creates a need for the ability to communicate a preferred direction of motion between both participants in order to move in coordinated way. This communication method should be bidirectional to be able to fully utilize both the robot and human capabilities. Moreover, often in cooperative tasks between two humans, one human will operate as the leader of the task and the other as the follower. These roles may switch during the task as needed. The need for communication extends into this area of leader-follower switching. Furthermore, not only is there a need to communicate the desire to switch roles but also to control this switching process. Impedance control has been used as a way of dealing with some of the complexities of pHRI. For this investigation, it was examined if impedance control can be utilized as a way of communicating a preferred direction between humans and robots. The first set of experiments tested to see if a human could detect a preferred direction of a robot by grasping and moving an object coupled to the robot. The second set tested the reverse case if the robot could detect the preferred direction of the human. The ability to detect the preferred direction was shown to be up to 99% effective. Using these results, a control method to allow a human and robot to switch leader and follower roles during a cooperative task was implemented and tested. This method proved successful 84% of the time. This control method was refined using adaptive control resulting in lower interaction forces and a success rate of 95%. / Dissertation/Thesis / M.S. Mechanical Engineering 2014

When an electric field is locally applied to tissues in vivo the uptake of exogenous DNA can be greatly increased. This approach to gene transfer, called electroporation (EP) or gene electro transfer (GET), has potential applications in the treatment of skin disorders, vaccinations, some types of cancer and metabolic diseases. The eect of electric elds on cells and tissues has been studied and related to the uptake of DNA. Tissue impedance changes have been measured as a result of electroporation. The aim of this study is to explore the predictive accuracy of impedance spectroscopy for the success of GET. Mice were used in this study for their histological similarities to human skin. The mice were injected with plasmid DNA coding for luciferase and given one of a series of electroporation treatments varying the number and intensity of the electric pulses delivered. The number of pulses delivered was based upon impedance measurements taken during the EP procedure. Mice were then imaged to quantitatively measure the luminescence resulting from the gene delivery procedure at intervals of 2, 4, 7, 10 and 14 days after treatment to quantitatively determine the biological response to gene electrotransfer. Increased luminescence was noticed in treatment groups compared to injection only groups, and the most eective treatments resulted from a feedback mechanism based upon percentage changes in skin impedance. The relationship between impedance change and gene expression suggested that treatment can be improved based on impedance measurements taken during the EP treatment.

A caracterização elétrica de materiais vítreos foi efetuada por meio da análise da condutividade em função da freqüência da amplitude do sinal (ac) e da condutividade dc, utilizando para tanto a técnica de espectroscopia de impedância (IS) e medidas da corrente elétrica direta em função da voltagem dc aplicada. As medidas de IS foram realizadas no intervalo de freqüência de 1 Hz até 1 MHz e em função da temperatura. Avaliou-se as propriedades elétricas de vidros oxifluoroboratos de chumbo (BPP), 50BO1.5 – (50-x)PbO – xPbF2, com x = 0, 5, 10, 15 e 20 (% catiônica). As amostras vítreas foram sintetizadas por mistura convencional e fusão das quantidades apropriadas dos reagentes. Observou-se que a condutividade dc aumenta com a temperatura seguindo a lei de Arrhenius, com uma única energia de ativação aparente para o processo de condução na matriz vítrea. Há também um aumento da condutividade em cinco ordens de grandeza, por uma relação “quase” linear, com o aumento do fluoreto de chumbo na composição das amostras. As técnicas de Calorimetria Exploratória Diferencial (DSC), Difração de Raios X (DRX), Microscopia Eletrônica de Varredura (MEV) e Espectrometria de Emissão Óptica com Plasma Acoplado Indutivamente (ICP-AES) foram empregadas para auxiliar no entendimento do sistema BPP e dos processos de condução envolvidos. A temperatura de transição vítrea e a densidade foram determinadas para todas as composições. As quantidades de boro e chumbo, determinadas pela técnica de ICP-AES, indicam uma perda de chumbo durante a preparação dos vidros, perda mais evidenciada para a composição de x = 20%. Com a aplicação de tensão dc sobre a amostra houve cristalização da fase &#946;-PbF2 e redução para chumbo metálico. / Electrical properties of lead oxifluoroborate glasses were investigated. Measurements were carried out by impedance spectroscopy (IS) in the frequency range from 1 Hz to 1 MHz and direct current (dc) measurements. All measurements were performed in a temperature between 25 and 300 °C. Glassy samples of 50BO1.5 – (50-x)PbO – xPbF2 system, where x = 0, 5, 10, 15 and 20 (cationic %), were synthesized by conventional mixing and melting of appropriate amounts of starting reagents. The glass conductivity increases with temperature following the Arrhenius law, with single apparent activation energy for conduction process. The lead fluoride addition even causes a conductivity enhancement which goes from 10-10 up to 10-4 S/cm at 250 °C. Differential Scanning Calorimetry (DSC), X-Ray Diffraction (DRX), Scanning Electron Microscopy (SEM) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) techniques were applied to aid in the understanding of the material and its conductive processes. Glass transition temperatures and density were available for all compositions. Boron and lead amounts, determined by ICP-AES, are evidence of a process in which a lead is lost, a reason for density reduction of the x = 20% composition. The use of dc voltage caused a &#946;-PbF2 phase crystallization and a lead reduction.

Cerâmicas de zircônia estabilizada com ítria são utilizadas na forma densa como eletrólito e na forma porosa como ânodo em células a combustível de óxido sólido. Neste trabalho cerâmicas porosas de zircônia estabilizada com 8 mol% de ítria foram preparadas por meio da adição de diferentes teores de KI, NaCl e grafite como aditivo sacrificial. A remoção térmica do aditivo foi avaliada por meio de análises termogravimétrica, térmica diferencial e dilatométrica. As amostras foram preparadas por meio de mistura, compactação e sinterização a 1400 ºC/2 h. As amostras foram caracterizadas por difração de raios X(DRX) e análise topográfica em microscópio de varredura por sonda e microscópio eletrônico de varredura de superfícies polidas e atacadas para avaliação da distribuição do teor de poros e tamanho médio de grãos. O teor do aditivo residual foi avaliado por fluorescência de raios X (FRX). O comportamento elétrico foi analisado por espectroscopia de impedância (EI) na faixa de frequências 5 Hz-10 MHz entre 300 ºC e 450 ºC. Os resultados de FRX mostram que não há resíduo do aditivo após sinterização. A análise de DRX indica que todas as amostras têm fase única, cúbica tipo fluorita. Os diagramas de impedância mostram que há aumento i) das resistividades elétricas intergranular e intragranular, evidenciando a formação de poros em ambas as regiões, ii) do ângulo de descentralização do semicírculo a baixas frequências, devido ao aumento do grau de heterogeneidade pela presença de poros, e iii) do produto do fator de bloqueio R pelo fator de frequência f, consequência do aumento do teor de poros. Esses resultados estão em concordância com os resultados das análises de microscopia de varredura por sonda e de microscopia eletrônica de varredura. / Dense and porous yttria-stabilized zirconia ceramics are used as electrolytes and anodes, respectively, in solid oxide fuel cells. Porous ZrO2: 8 mol% Y2O3 (8YSZ) were prepared by using NaCl, KI and graphite as sacrificial additives. The thermal removal of the additives was evaluated by thermogravimetry, differential thermal analysis and dilatometry. The samples were prepared by thoroughly mixing 8YSZ to the additives, pressing and sintering at 1400 ºC/2 h. The samples were characterized by X-ray diffraction (XRD) and by observation of polished and etched surfaces in scanning probe microscope (SPM) and scanning electron microscope (FEG-SEM) to evaluate pore content. The evaluation of the NaCl and KI content was carried out by X-ray fluorescence (XRF) analysis. The electrical behavior was analyzed by impedance spectroscopy (IS) in the 5 Hz-10 MHz frequency range from 300 ºC to 450 ºC. The XRF results show no remaining KI or NaCl in the sintered samples. The XRD patterns show all samples are single cubic fluorite phase. The IS plots show that there is an increase i) of the intergranular and the intragranular electrical resistivity, an indication of bulk and grain boundary pore formation, ii) of the decentralization angle of the grain boundary semicircle in the impedance plots due to increasing heterogeneity of the samples, and iii) of the product of the blocking factor R to the frequency factor f, as a consequence of the increase in pore content. These results are in agreement with the SPM and SEM observations.

Made available in DSpace on 2014-10-09T12:34:05Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:48Z (GMT). No. of bitstreams: 0 / Eletrodos à base de carbono, como os eletrodos de troca iônica, entre outros, têm aplicação principalmente no tratamento de efluentes industriais e rejeitos radioativos. Carbono é também amplamente utilizado em células a combustível como substrato para os eletrocatalisadores, por possuir elevada área superficial, que supera a sua área geométrica. O conhecimento desta superfície ativa total é importante na determinação das condições de operação de uma célula eletroquímica no que diz respeito às correntes a serem aplicadas (densidade de corrente). No presente estudo foram utilizadas duas técnicas eletroquímicas na determinação da área superficial ativa de eletrodos de carbono vítreo e poroso e eletrodos de troca iônica: espectroscopia de impedância eletroquímica (EIE) e voltametria cíclica (VC). Os experimentos foram realizados com soluções de KNO3 0,1 mol.L-1 em célula eletroquímica de três eletrodos: eletrodo de trabalho à base de carbono, eletrodo auxiliar de platina e eletrodo de referência de Ag/AgCl. Os eletrodos de carbono vítreo e de carbono poroso utilizado possuíam uma área geométrica de 3,14 x 10-2 cm2 e 2,83 10-1 cm2, respectivamente. O eletrodo de troca iônica foi preparado misturando-se grafite, carbono, resina de troca iônica e um aglutinante, sendo esta mistura aplicada em três camadas sobre feltro de carbono, utilizando-se nos experimentos uma área geométrica de 1,0 cm2. Por EIE determinou-se diretamente a capacitância dos materiais dos eletrodos (Cd) utilizando-se os diagramas de Bode. O valor de 172 &mu;F.cm-2 encontrado para o carbono vítreo está de acordo com a literatura (~200 &mu;F.cm-2). Por VC, variando a velocidade de varredura de 0,2 a 2,0 mV.s-1, determinou-se a capacitância CdS (S=área superficial ativa) na região da dupla camada elétrica (DCE) para cada um dos materiais, Por EIE, foram determinados os valores de Cd de 3,0 x 10-5 &mu;F.cm-2 e de 11,0 x 103 &mu;F.cm-2 para os eletrodos de carbono poroso e de troca iônica, respectivamente, o que possibilitou a determinação das áreas superficiais ativas de 3,73 x 106 cm2 e 4,72 cm2. Portanto, o uso combinado das técnicas de EIE e VC mostra-se promissor para o cálculo das áreas superficiais ativas de eletrodos à base de carbono. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP