This thesis has been motivated by the growing needs for multi-degree of freedom (M-DOF) electromagnetic actuators capable of smooth and accurate multi-dimensional driving motions. Because high coercive rare-earth permanent-magnets (PMs) are widely available at low cost, their uses for developing compact, energy-efficient M-DOF actuators have been widely researched. To facilitate design analysis and optimization, this thesis research seeks to develop a general method based on distributed source models to characterize M-DOF PM-based actuators and optimize their designs to achieve high torque-to-weight performance with compact structures To achieve the above stated objective, a new method that is referred to here as distributed multi-level current (DMC) utilizes geometrically defined point sources has been developed to model electromagnetic components and phenomena, which include PMs, electromagnets (EMs), iron paths and induced eddy current. Unlike existing numerical methods (such as FEM, FDM, or MLM) which solve for the magnetic fields from Maxwell’s equations and boundary conditions, the DMC-based method develops closed-form solutions to the magnetic field and force problems on the basis of electromagnetic point currents in a multi-level structure while allowing trade-off between computational speed and accuracy. Since the multi-level currents can be directly defined at the geometrically decomposed volumes and surfaces of the components (such as electric conductors and magnetic materials) that make up of the electromagnetic system, the DMC model has been effectively incorporated in topology optimization to maximize the torque-to-weight ratio of an electromechanical actuator. To demonstrate the above advantages, the DMC optimization has been employed to optimize the several designs ranging from conventional single-axis actuators, 2-DOF linear-rotary motors to 3-DOF spherical motors. The DMC modeling method has been experimentally validated and compared against published data. While the DMC model offers an efficient means for the design analysis and optimization of electromechanical systems with improved computational accuracy and speed, it can be extended to a broad spectrum of emerging and creative applications involving electromagnetic systems.

Pastaruoju metu biodujų gamyba, gamybos technologijos yra gana aktualios. Biodujų gamyboje tikslinga taikyti naujausias technologijas norint padidinti biodujų išeigą. Darbo tikslas: Ištirti elektromagnetinių laukų stiprių (H) ir poveikio trukmių (τ) įtaką biodujų išeigai. Atlikus literatūros šaltinių analizę, kai kurie autoriai užsimena apie elektromagnetinių laukų poveikių įtaką biodujų išeigai. Eksperimentiniai tyrimai atlikti Aleksandro Stulginskio universiteto biodujų laboratorijoje. Baigiamajame darbe atliktų eksperimentinių tyrimų rezultatai rodo, kad elektromagnetinių laukų stipriai, šių laukų poveikio trukmė įtakoja biodujų išeigą. / Lately production of biogas and production technology is relevant. In biogas production it is appropriate to apply the newest technologies in order to increase biogas yield. The aim – to research electromagnetic fields strength (heart) and the durations of exposures (τ) influence on biogas yield. After literature analyzing, it was revealed that some authors talk about electromagnetic fields influence on biogas yield. Experimental research was done in university of Aleksandras Stulginskis, biogas laboratory. Thesis results of experimental research shows that electromagnetic fields strengths and that field’s duration of exposure have influence on biogas yield.

Resumo: Neste trabalho é apresentada a modelagem analítica baseada nas equações de Maxwell e a modelagem numérica baseada no Método da Simulação de Cargas (MSC) e no Método dos Elementos Finitos (MEF) empregados no cálculo do campo eletromagnético quase-estático em linhas de transmissão. O método dos elementos finitos consiste numa adaptação do método residual de Galerkin. Ele é atualmente considerado um método matemático para a solução de equações diferenciais parciais, entre as quais se inclui a Equação de Poisson, Equação de Laplace, Equação de Helmholtz, Navier-Stokes, etc. Esse é um método de aproximação de problemas contínuos em domínios fechados onde o contínuo se divide em um número finito de partes, ou elementos, cujo comportamento se especifica mediante um número finito de parâmetros associados a certos pontos característicos denominados nós. Os nós são os pontos de união de cada elemento com seus adjacentes. A solução do sistema completo segue as regras dos problemas discretos. O sistema completo se forma pela associação dos N elementos. As incógnitas do problema deixam de ser funções matemáticas e passam a ser o valor dessas funções nos n nós. O comportamento no interior de cada um dos N elementos passa a ser definido a partir do comportamento dos n nós, mediante adequadas funções de interpolação ou funções de forma. A precisão do método depende da forma do elemento da malha bidimensional, ou seja, se ele é triangular ou quadrilateral, por exemplo. Além disso, a quantidade de pontos de integração e conseqüentemente a base polinomial do elemento finito, podem ser explorados para aumentar a precisão dos resultados. A base do método dos elementos finitos são as funções de mapeamento, e suas derivadas. No método de Galerkin as funções de mapeamento são igualadas às funções de forma originando os elementos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this research is presented a mathematical modeling based on Maxwell's equations and numerical modeling based on Charge Simulation Method (CSM) and the Finite Element Method (FEM) for calculating the quasi-static electromagnetic field in transmission lines. The finite element method is an adaptation of Galerkin residual method. It's currently considered a mathematical method for solving partial differential equations, among which includes the Poisson equation, Laplace equation, Helmholtz equation, Navier-Stokes, etc. This is an approximation method of continuing problems in closed domains where the continuous is divided into a finite number of parts or elements whose behavior is specified by a finite number of parameters associated with certain characteristic points called nodes. The nodes are union points of each element with its adjacent. The solution of the entire system follows the rules of the discrete problems. The complete system is formed by the association of N elements. The unknowns of the problem, mathematical functions, become the value of these functions on n nodes. The behavior within each of elements N is now defined from the behavior of n nodes, using appropriate interpolation functions or shape functions. The method precision depends on the shape of two-dimensional mesh element, i.e., if it is triangular or quadrilateral. Moreover, the number of integration points and therefore the polynomial finite element basis, can be exploited to increase the accuracy of the results. The basis of the finite element method are the mapping functions and their derivatives. In the Galerkin method the mapping functions are matched to the shape functions form the isoparametric. Finally, from above definitions, simply refer to the tables of numerical integration, showing how the elements are integrated, and use them in the rest of the numerical modeling / Orientador: Luiz Fernando Bovolato / Coorientador: Carlos Alberto Tenório de Carvalho Júnior / Banca: Afonso José do Prado / Banca: Sérgio Kurokawa / Banca: Olivio Carlos Nascimento Souto / Banca: Wander Gonçalves da Silva / Doutor

Microcystis são cianobactérias que apresentam formações de florações e produção de microcistina, uma hepatotoxina que causa envenenamentos e promove tumores hepáticos. Os objetivos deste trabalho foram estudar o efeito combinado da radiação gama com outros agentes físicos em células de Microcystis panniformis e investigar a atenuação da microcistina através da ação de feixes de nêutrons e elétrons e radiação gama. Observou-se que os tratamentos combinados aumentaram a inviabilidade celular e que houve atenuação da microcistina após a sua exposição aos três tipos de radiações ionizantes. Com a combinação de agentes físicos é possível reduzir as doses necessárias para o controle populacional de Microcystis panniformis e a exposição à feixes de elétrons é a radiação indicada para maior atenuação da microcistina. / Microcystis are cyanobacteria exhibiting blooms formation and production of microcystin, a hepathotoxin responsible for poisoning and consequent development of hepathic tumors. The goals of this work are the study of the combined effect between gamma radiation with other exogenous physical agents in cells of Microcystis panniformis, as well to investigate the attenuation of microcystin by neutron and electron beams and gamma radiation. It was found out that combined treatments, as radiation with another physical agent, caused lowering of the cellular viability and that had attenuation of microcystin after your exposition at three kind of ionizing radiation. The results showed that with the association of physical agents it is possible to reduce the doses needed for the population control of Microcystis panniformis and that exposition of electron beams have proved to be the most indicated radiation type for attenuation of microcystin.

O desenvolvimento da tecnologia de telecomunicação móvel ensejou a implantação massiva de ERBs (Estações rádio base) para o atendimento da crescente demanda ocorrida na última década. As ERBs, por sua vez, constituem fontes emissoras de radiação não ionizante. Os estudos científicos concluídos nos últimos anos indicam que a exposição à radiação não ionizante, principalmente em longo prazo, pode produzir consequências negativas para a saúde humana, por essa razão, mister se faz a aplicação do Princípio da Precaução que vem evocar cautela diante do risco. Das principais normas existentes no planeta, nem todas adotaram o princípio da precaução ao fixar seus limites; em decorrência, a maioria das normas que determinam limites máximos de exposição teve como base apenas os efeitos biológicos danosos da exposição à radiação não ionizante já conhecidos pela comunidade científica e relacionados à exposição aguda. Dessa maneira, diante do risco resultante da exposição, surge outra questão de grande importância o gerenciamento dessas ERBs. Haveria, na cidade de São Paulo, um sistema de gerenciamento das ERBs que garanta o cumprimento dos limites e padrões definidos na legislação local? Nesse cenário, este estudo pretende: (i) elaborar um levantamento junto aos três órgãos públicos responsáveis pelo gerenciamento das ERBs na cidade de São Paulo, sobre o atual estágio dos sistemas de gerenciamento praticado por cada entidade pública legalmente competente para o respectivo exercício; (ii) desenvolver uma análise das características básicas dos sistemas de gerenciamento das ERBs no município de São Paulo, estudando a evolução ocorrida entre os anos de 2006 e 2011; e, (iii) avaliar as possibilidades de melhoria na proposta atual de gerenciamento das ERBs, no município de São Paulo. Esta pesquisa parte dos dados levantados no ano de 2006, na cidade de São Paulo, que na ocasião indicaram a existência de um sistema de gerenciamento das ERBs incipiente e frágil por parte dos órgãos públicos competentes (Secretaria Estadual da Saúde, Secretaria Municipal do Verde e Meio Ambiente e ANATEL). A partir deste cenário, elabora-se uma análise das características básicas dos sistemas de gerenciamento das ERBs no município de São Paulo, estudando a evolução ocorrida entre os anos de 2006 e 2011. Dessa avaliação, são identificadas falhas e possibilidades de melhoria nos sistemas de gerenciamento das ERBs praticados no município de São Paulo na atualidade. A metodologia adotada constitui-se de pesquisa de campo, por meio de entrevista estruturada, aplicada aos representantes dos órgãos públicos responsáveis pelo gerenciamento das ERBs no município de São Paulo. Finalmente, é desenvolvida a interpretação dos dados, global e individualmente, de forma que os resultados obtidos possibilitaram as considerações e propostas formuladas no capítulo conclusivo desta pesquisa. / The development of mobile telecommunication technology gave rise to the massive deployment of RBSs (Radio base stations) to attend the growing demand occurred in the last decade. The RBSs in turn, are emitting sources of non-ionizing radiation. Scientific studies concluded in the recent years indicate that exposure to non-ionizing radiation, especially in the long term, can produce negative consequences for human health, therefore, it becomes important to apply the Precautionary Principle that evokes caution in risk situation. Of the main rules in the world, not all adopted the precautionary principle in setting its limits; as a result, most of the rules that determine maximum exposure limits were based only on the harmful biological effects of exposure to ionizing radiation already known by the scientific community and related to acute exposure exclusively. Thus, with the risk resulting from exposure, there is another major issue - the management of these RBSs. Would it exist, in São Paulo city, a management system of RBSs to ensure compliance with the limits and standards defined by local law? In this scenario, this study aims to: (i) develop a survey along the three entities responsible for managing the RBSs in São Paulo, on the current stage of respective management systems practiced by each public entity legally responsible for the exercise thereof; (ii) develop an analysis of the basic features of the RBSs management systems in São Paulo, studying the evolution that occurred between the years 2006 and 2011; and, (iii) assess the possibilities for improvement in the current proposal for the RBSs management in São Paulo. This survey starts from the data collected in 2006, in São Paulo, which at the time indicated the existence of an incipient and fragile RBSs management system, by the public agencies (Secretaria Estadual da Saúde, Secretaria Municipal do Verde e Meio Ambiente e Anatel). From this scenario, it is drawn up an analysis of the basic features of the RBSs management systems in São Paulo, studying the evolution that occurred between the years 2006 and 2011. From this evaluation, are identified gaps and opportunities for improving the RBSs management systems practiced in São Paulo at present. The methodology consisted of field survey through structured questionnaires, applied to representatives of public agencies responsible for RBSs management in São Paulo. Finally, it is developed the interpretation of the data, overall and individually, so that the results enabled the considerations and proposals made in the concluding chapter of this research.

This thesis deals with the idea of energy harvesting from mechanical vibration. It describes the magnetostrictive principle as a possibility to obtain an electrical energy. It is about a generator made of a beam with Terfenol-D material and a coil. The model of this device is created in Matlab/Simulink and FEMM application. For various values of measured vibration, these methods are then compared. In FEMM, you can improve energy gain by modeling of various environmental conditions and with using of another materials (e.g. by adding of permanent magnets). The outcome of the this thesis expresses the ability to harvest the energy with designed magnetostrictive generator compared to the already created models of the piezoelectric and electromagnetic generator. Based on these results, it is possible to determine which generator is more suitable for particular application.

Aircraft have been used for the detection of submarines since World War II. The basic concept is to attach a sensor to the back of an aircraft. Since the aircraft is a moving metallic object, it is bound to generate a great deal of interference. Because of this, mathematical models and software have been developed to help filter out this interference and thus make the detection of the submarine easier. Normally, the engines of the aircraft are placed on the wings, quite far away from the sensor. However, for a maritime patrol system in development, the jet engines are placed at the rear of the airframe, generating the necessity to study whether or not they affect the performance of the sensor, which is the purpose of this thesis.   Several models were created, tested and simulated for the airframe and jet engines. One of each of these were then combined to create a simulation model for the complete aircraft. A jet engine model that included rotating machinery -- a possible source of magnetic interference -- was also created, but could not be added to the model for the complete aircraft. The magnetic interference was mathematically compensated for, removing the static interference, but not the interference during manoeuvres. The jet engine part of the complete aircraft model did not seem to generate a significant amount of magnetic interference compared to the airframe. An electric dipole, representing a submarine, was then added to the simulation. The data from that simulation was put through the mathematical model and distortions of a few~nT were noticeable during straight courses. The jet engine model that included rotating machinery yielded different results compared to the jet engine model in the complete aircraft model. They seemed to contain signals of higher frequency, which were however not detected by a frequency domain study or present during straight courses. It was thus concluded that using this particular engine model the submarine could probably still be detected if the course of the aircraft was kept straight, though further research is needed with more advanced models for the engine, in particular with regards to the rotating machinery.

Atlikus literatūros apžvalgą, remiantis teoriniais ir eksperimentiniais tyrimais, įsitikinta, kad elektromagnetiniai laukai turi įtakos žmogui ir aplinkai. Elektromagnetinio lauko poveikiui daugiausiai jautri centrinė nervinė ir neuroendokrininė sistemos. Didžiausi elektromagnetinių laukų šaltiniai, gyvenamojoje ir darbo aplinkoje, yra buitiniai prietaisai, elektros perdavimo, transformavimo ir skirstomieji įrenginiai. Elektros įrengimų kuriami elektromagnetiniai laukai, erdvėje sklinda pagal 1/r3; 1/r2 ir 1/r dėsnius. Tai charakteringa tiek elektrinių, tiek magnetinių laukų verčių kitimui. Elektromagnetinių laukų parametrų vertę apsprendžia elektros įrenginių įtampa, srovė ir tiriamo taško padėtis įrenginių atžvilgiu. Įvertinant labai platų mūsų šalies energetikos tinklą, naudojamų elektros įrenginių, kuriančių elektromagnetinius laukus gyvenamoje ir darbo aplinkoje, duomenys apie tai įgauna ženklią socialinę prasmę, sudaroma galimybė prognozuoti galimas silpnų elektromagnetinių laukų poveikio reikšmes, numatyti priemones joms pašalinti. / Literary review, according to theoretical and experimental researches, it was noticed that electromagnetic fields of industrial frequency influence the human and environment. The most sensitive parts to the effect of electromagnetic fields are the nervous system and the neuroendocrine system. The biggest sources of electromagnetic fields are the domestic appliances, the installations of electricity transmission, transference and the distributing installations in residential and working places. Electromagnetic fields are generated with electric installations and spread in space by 1/r3; 1/r2 and 1/r law. It is typical of the value change of electric and magnetic fields. Parameter value of electromagnetic fields is solved with electricity installations tension, stream and the location of analyzed point in point of installations. Summing up the wide energetic net of our country, the fact of usable electric installations (which create electromagnetic fields in residential and working places) assume the marked social signification, there is posed the opportunity to forecast the available values of low electromagnetic fields effect, and to forecast means to remove it.

This study employed multiple assessments, including sleep/resting waking EEG (visual scoring and power spectral analysis) and psychomotor vigilance task, to access effects of varying pulse-modulated microwaves (such as: 'talk', 'listen' and 'standby' mode signals) emitted from a standard mobile phone. The idea was prompted by a finding that the pulse modulation frequencies of mobile phone signals correspond to the frequencies of brain delta and alpha waves. Thereby it is possible the brain is able to recognize and respond to the low-frequency components of the mobile phone signals. Supporting evidence comes from repetitively reported EEG alpha and spindle effects of the 2, 8 and 217-Hz pulsed microwave exposure. Furthermore, brain imaging (EEG and PET) studies reveal 'low-frequency pulse-modulated waves' rather than the 'microwave frequency carrier waves' is the sine qua non for inducing these brain physiological effects [Huber et al., 2002, 2005; Regel et al., 2007a]. On the other hand, recent converging evidence, from molecular, behavioural and electrophysiological level, have shown that brain plasticity is a continuous process from waking to sleep and, sleep, a well-defined physiological condition, is 'shaped' by the waking experiences. The latter findings suggest certain sleep EEG features may characterize levels of cortical plasticity during wakefulness. The work presented in this thesis was inspired by these studies and aimed to understand how the real mobile phone signals with different low-frequency pulsing components [such as 'talk' (8, 217 Hz pulsed), 'listen' (2, 8, 217 Hz pulsed) and 'stand by' mode < 2 Hz pulsed)] change human brain electrical activities from waking to sleep. We approached this question based on EEG analysis in two domains: (1) EEG visual scoring; (2) EEG spectral analysis from relaxed waking to the deeper stages of non-NREM sleep. We also looked at the effects on the psychomotor vigilance performance. Results suggest 'talk' and 'Iisten/standby' modes have inverse effects on the distinctive thalamo-cortical oscillation modes and may thus impart inverse effects on their sleep structures. The implications of this study are of practical importance as it suggests the thalamo-cortical oscillations can be modulated by synchronizing rTMS/tDCS/DBS and sleeplwaking EEG. This concept may be applied to modulate the brain oscillation modes for enhancing sleep-dependent brain plastiCity or information processing.

La nanotechnologie est un domaine en voie d'expansion qui a attiré l'attention de la recherche en raison de ses applications potentielles illimitées. La technologie des ondes millimétriques est un autre domaine intéressant qui joue un rôle de premier plan dans le développement des systèmes de communications sans fil. La combinaison de ces deux champs de recherche avancée, donne naissance à l'innovation du Dispositif Ratchet qui est une nouvelle application qui représente un vrai défi. Ce dispositif est de taille nanométrique et son concept d'opération consiste à générer une tension DC lorsque le dispositif, basé sur le gaz d'électron bidimensionnel, est rayonné par l'énergie des micro-ondes. L'objectif de cette thèse est d'essayer d'améliorer la réponse du dispositif, ce qui ouvre de nouvelles perspectives dans la fabrication des détecteurs de champ à haute fréquence et à l'échelle nanométrique. Malheureusement, les Dispositifs Ratchet actuels, basés sur des hétérostructures de semiconducteurs, réalisés jusqu'à présent fonctionnent à basse température pour assurer une grande mobilité électronique. Cette condition nécessite l'utilisation d'un setup expérimental complexe qui a un grand impact sur la tension induite et sur la reproductibilité du phénomène Ratchet observé. Dans ce contexte, le travail effectué dans le cadre de cette thèse a abordé ce problème en deux parties. La première partie concerne l'analyse électromagnétique du setup expérimental. Ceci a été réalisé par la mise en oeuvre des simulations électromagnétiques intenses. D'autre part, différentes solutions ont été proposées afin d'optimiser le setup et ainsi améliorer la tension Ratchet produite. Outre l'étude électromagnétique, certaines mesures de modulation ont été réalisées pour tester la faisabilité du Dispositif Ratchet comme un démodulateur d'amplitude. La deuxième partie de cette thèse traite l'étude de la matière qui compose le Dispositif Ratchet. Récemment, le graphène commence à envahir le monde scientifique et technologique avec ses fascinantes propriétés électroniques, tels que sa mobilité d'électrons élevée à température ambiante, où les matériaux conventionnels sont en train de confronter des obstacles. En conséquence, l'idée de fabriquer un Dispositif Ratchet à base de graphène au lieu des hétérojonctions de semiconducteurs, a été introduite. Plusieurs modèles de conception, caractérisation et mesures RF ont été accomplis en vue d'obtenir un Dispositif Ratchet fiable approprié pour de nombreuses applications pratiques à la température ambiante, dans la gamme de fréquences micro-ondes et pourraient s'étendre à la bande térahertz. / Nanotechnology is a growing field that has attracted significant research attention due to its unlimited potential applications. Millimeter wave technology is another interesting field that plays a leading role in the development of wireless communications systems. Combining these two advanced research fields together, has given rise to the innovation of the Ratchet Device which is now a new challenging application. This device has a nanoscale size and its concept of operation consists of generating a DC voltage when radiating a two-dimensional electron gas based device with microwave energy. The aim of this thesis is in trying to improve the device response and hence opening new perspectives in the fabrication of high frequency field detectors on the nanoscale level. Unfortunately, the current Ratchet Devices, based on semiconductor heterostructures, realized till now, operate at low temperatures to ensure high electron mobility. This condition necessitates the use of a complex experimental setup that has a great impact on the induced voltage and on the reproducibility of the observed Ratchet phenomenon. In this context, the work performed within the framework of this thesis has addressed this problem in two parts. The first part concerns the electromagnetic analysis of the experimental setup behavior. This has been achieved by implementing intensive full wave electromagnetic simulations. Different solutions have been proposed to optimize the setup and thus enhance the Ratchet voltage produced. In addition to the electromagnetic study, some modulation measurements have been performed to test the feasibility of the Ratchet Device as an amplitude demodulator. The second part of this thesis deals with the study of the material composing the Ratchet Device. Recently, graphene has started to invade the scientific and the technological world with its fascinating electronic properties, such as its high electron mobility at room temperature, which distinguishes it from conventional materials that typically collide with obstacles. As a result, the idea of fabricating a Ratchet Device based on graphene instead of semiconductor heterojunctions has been introduced. Several design models, characterizations and RF measurements have been performed in order to obtain a reliable Ratchet Device suitable for many practical applications at room temperature. This has been done in the microwave frequency range and can also extend to the terahertz band.