Atherosclerotic plaques in the bifurcation of the carotid artery vessels can pose a significant stroke risk from stenosis, thrombosis and emboli, or plaque rupture. However, the possibility of the latter depends on the structure of the plaque and its stability. So far, the assessment of such depositions, and the evaluation of the risk they pose, is not satisfactory with 3 Tesla black blood imaging. It is expected that the SNR increase at 7 Tesla, together with an appropriate and patient-safe RF coil, will result in higher resolution images that would help in better assessing the composition of atherosclerotic plaques in vessel walls. A custom-built neck array was designed and constructed, with the aim of investigating the benefits of the higher field strength using DANTE-prepared black blood imaging. A 4-channel transmit array was designed to generate the required <b>B</b>^&plus;<sub style='position: relative; left: -.5em;'>1</sub> field for the DANTE module to be used. A separate close fitting 4-channel receive array was preferred for improved SNR and parallel (receive) imaging. Geometric, active, passive as well as preamp decoupling schemes were employed for adequate isolation between the arrays and their channels. Electromagnetic simulation software, Semcad X (SPEAG, Zurich), was used for safety assessment with human phantoms (Virtual population). The <b>E</b> fields for 1 W transmission per channel were calculated for each element for a worst case SAR estimation. The transmission power limits per channel were set according to the 10g SAR limit set in IEC 60601. For simulation validation, temperature measurements and surface heat mapping were performed on a meat phantom. Finally, a healthy male subject was scanned using a protocol consisting of <b>B</b>₁ mapping, RF shimming at an ROI, and 2D and 3D DANTE prepared Gradient Echo (GRE). The worst-case heating scenario, as defined in the methods section, generated a maximum local SAR of 7.65 W/kg for 1 Watt per channel input. Thus, for 1st level mode (20W/kg max), the power limit was set at 2.6 W per channel. The heating profile was similar to that simulated and the measured temperature increase was within a &plusmn;10&percnt; margin relative to the simulation. The global SAR power limit per channel was found to be higher (i.e. more allowed power) than the worst case local SAR power limit, and thus did not impose additional power penalty. The resolution achieved was 0.6 mm isotropic for the 3D protocol and 0.6 by 0.6 by 2.5 mm for the 2D protocol. The average SNR was measured within the vessel wall location of the two carotid arteries and found to be 27&plusmn;6 for the DANTE images and for the static tissue closer to the skin the SNR was 55&plusmn;2. In conclusion, a 4Tx/4Rx coil was designed to target the carotid arteries operating under pTx mode and a black blood imaging sequence was implemented for blood signal suppression and vessel wall imaging. The initial results from the subject and phantom imaging show satisfactory blood suppression and spatial resolution.

This thesis presents postpenitentiary care / after care and its basic definition. It also discusses the use of coaching approaches in the after-care. The main objective of this thesis is to design and test the suitability and efficiency of leadership coaching approaches in after-care interviews. In the introduction of coaching approaches, I present the results from tests done with a research group made of former prisoners from facilities based in Prague, who left in the period between 17th 2010 and 24 5th The 2011th. A key finding is that researchers proved the suitability of the use of variable roles. In the following thesis, I define the three main borders and two roles that can be used for client access. The basic forms of access to clients can be identified as the approach of coach, child behavioral / ethopedy and social worker. Boundary roles can be described as a role transition between the essential roles. Through roles based on current client's needs, it can help to develop various personalised ways towards the independence. This thesis can serve as input into the area of after-care treatment. It also introduces a possibility to access after-care providers by enriching other possible approaches to clients.

This thesis focuses on inductive base sensor design at MHz range frequency. The background theory, design, experiments and results for a new magnetic particles sensor is presented. A new magnetic sensor based on a planar coil was investigated for DNA pathogen detection. Change in inductance of the planar coil due to the presence of magnetic particles with varying mass was measured. The experimental set-up consisted of different sized planar coil with associated electronics for inductance measurements. The best sensor performance was accomplished using two different inductors while oscillating at frequencies 2.4MHz using 9.5μH inductor and 7.2MHz with 85μH inductor. The sensor has very large signal to noise ratio (580×103), while the average amount of frequency drift was 0.58. This sensor was tested with various types of magnetic particles. In addition, iron-oxide nanoparticles were synthesized through water in oil microemulsion method and with an average size of 25nm. The best sensitivity achieved for detection of 50μg iron-oxide particles was with the bead size of 10nm. 81Hz frequency shift was attained in regard to that amount of particles. This research shows that increasing the resonance frequency to 7.2MHz can cause the larger output signal difference (frequency shift) in the presence of magnetic particles; however, the sensor stability is the most important factor for determining the detection resolution and sensitivity. The sensitivity is better if the sensor can detect smaller amount of magnetic sample. The results of this research demonstrate that while the sample consists of smaller size particles, the sensor can detect the lower amount of sample. This is due to the heating effect of nanoparticles. On the other hand the sample distance from the sensor has a major impact on the sensitivity too; the shorter the distance, the higher the sensitivity. This technique can potentially be extended to detect several different types of bacterial pathogens and can be modified for multiplex quantitative detection. This sensing technique will be incorporated into a handheld, disposable microfluidic chip for point-of-care diagnostics for sexually transmitted diseases.

Dans le domaine du véhicule électrique, la chaîne de traction allant de la batterie de stockage aux roues en passant par le moteur constitue le cœur du système. Elle bénéficie régulièrement d’innovations technologiques rendant ce véhicule de plus en plus attractif. Actuellement, les motorisations proposées par les constructeurs sont classiques, de type synchrone à rotor bobiné, à aimant permanent ou asynchrone. De conception éprouvée et dotées de lois de commande complexes et parfaitement maîtrisées, elles offrent de bonnes performances.Cependant, les industriels explorent de nouvelles motorisations moins conventionnelles permettant de réduire leur coût de fabrication, tout en maintenant les performances. Une des solutions possibles est la machine à réluctance variable à double saillance (MRVDS). En effet, elle est de conception simple et constituée de matériaux peu couteux. Son rotor complètement passif lui confère une très bonne robustesse et une vitesse de rotation élevée, nécessaire à une certaine compacité.Néanmoins, son pilotage est beaucoup plus complexe que pour les autres machines, elle est relativement bruyante et son couple présente des ondulations non négligeables.Nos travaux ont pour but de contribuer à l’amélioration des performances de la MRVDS du point de vue contrôle, caractéristiques de couple et efficacité énergétique sur une plage de vitesse importante. Ils ont alors été conduits selon deux axes : un axe commande et un axe conception.Afin de satisfaire un contrôle du couple le plus parfait possible, de nouveaux régulateurs de courant à la fois performants et relativement simples à implémenter sur cible logicielle ont été présenté dans un premier temps. Ensuite, nous avons proposé une implémentation partitionnée de la commande de la MRVDS sur cibles logicielle et matérielle. L’objectif est ici de conserver les performances de la commande dans le cas de l’utilisation d’un processeur économique, dont la période d’échantillonnage serait relativement importante, et tout particulièrement à haute vitesse. Une carte FPGA (Fied Programmable Gate Array) a alors été mise en œuvre.Pour améliorer les caractéristiques de couple en fonction de la vitesse ainsi que le rendement de l’ensemble moteur-convertisseur, une nouvelle structure de MRVDS non conventionnelle a été proposée. Elle est munie d’un bobinage auxiliaire créant une excitation magnétique dans chaque phase.Une étude a d’abord été menée à l’aide de simulations basées sur un nouveau modèle. Elle a permis de mettre en évidence les avantages d’une excitation par rapport à une MRVDS classique. Afin de valider les résultats, un prototype a ensuite été conçu, réalisé et expérimenté.Une part importante de ces travaux a ainsi été consacrée à la mise en œuvre de plateformes expérimentales et à la réalisation de nombreux essais permettant de valider les développements théoriques, tant du point de vue commande sur une MRVDS 8/6 que conception sur une MRVDS 6/4. / For electric vehicles, traction from storage battery to the wheels through the engine is the heart of the system. It regularly enjoys technological innovations making this vehicle more attractive. Currently, machines offered by manufacturers are classic, synchronous and induction machines. With complex laws, they offer good performance.However, manufacturers are exploring new unconventional machines to reduce their manufacturing cost while maintaining performance. One possible solution is the switched reluctance machine (SRM). Indeed, its design is simple and made of inexpensive materials. Its rotor completely passive gives it a very good robustness and high rotational speed required for certain compactness. However, its operation is much more complex than for other machines, it is relatively noisy and has significant torque ripple.Our work contributes to the improvement of SRM’s performance in terms of control torque characteristics and global efficiency over a large range speed. They were driven on two axes: one control axis and one design axis.To satisfy a torque control as perfect as possible, new currents controller both efficient and relatively simple to implement on software target were first presented. Then we proposed a SRM's control implementation on hardware and software targets. The objective is to maintain the performances in the case of an important sampling period, especially at high speeds. So an FPGA circuit (Fied Programmable Gate Array) was used.To improve torque characteristics depending on the speed, and global efficiency, a new SRM structure has been proposed. It is provided with an auxiliary coil creating a magnetic excitation in each phase. A study was initially conducted using simulations based on a new model. It helped to highlight the benefits of excitement compared to a conventional SRM. To validate the results, a prototype was then designed, built and tested.An important part of this work has been devoted to the implementation of experimental platforms and implementation of numerous tests to validate the theoretical developments, both in terms of control on a 8/6 SRM and design on a 6/4 SRM.

På uppdrag av Sundsvall Energi AB har FVB Sverige AB påbörjat en förstudie kring etableringen av fjärrkyla i Sundsvall. Produktionsmedlen i det planerade nätet kommer att innefatta frikyla från akviferen och en kompressordriven kylmaskin. Det övergripande syftet med projektet har dels varit att ta fram en optimal framledningskurva, samt att ta reda på i vilken utsträckning frikylan kan nyttjas innan kylmaskinen måste användas som spetsproduktionsmedel. Projektet har inledningsvis fokuserat på att undersöka hur klimatet och kylbehovet ser uti Sundsvall. Kylbehovet granskades utifrån sex befintliga byggnader som nyttjar dricksvattenkyld fjärrkyla i Sundsvall. Därefter undersöktes olika typer av klimatsystem för att utröna vad de har för krav på framledningstemperaturen. Det konstaterades att kylbatterier var den komponent som kräver lägst framledningstemperatur, varför kyleffektberäkningar utfördes på dem. Resultatet ur kylbatteriberäkningarna fick motsvara den av fjärrkylenätet avgivna kyleffekten vid varierande utomhustemperatur. Genom att väga den avgivna kyleffekten vid varierande framledningstemperatur mot det erforderliga kyleffektbehovet vid varierande utomhustemperatur kunde framledningskurvan ta form. Akviferen antas hålla en temperatur på omkring 7°C till 9°C året runt, men utgångspunkten i detta projekt har varit att den konstant är 9°C. Under de förutsättningarna har framledningstemperaturen kunnat bestämmas till att vara 11°C under större delen av året, men att den sänks vid en utomhustemperatur på omkring 21°C i varierande grad ned till 6°C vid utomhustemperaturen 25°C. Med hjälp av framledningskurvan kunde därefter frikylans täckningsgrad bedömas. Resultatet visar att om framledningens temperatur höjs med 0,5–1,0°C i distributionsnätet kommer kylmaskinen att behöva vara i drift under 159 timmar per år. Om istället uppvärmningen blir 1,5° eller 2,0°C kommer kylmaskinen behöva vara i drift under 233 timmar respektive 325 timmar. Sammantaget har samtliga av projektets konkreta och verifierbara mål besvarats. / On behalf of Sundsvall Energi AB, FVB Sverige AB has initiated a preliminary study on the establishment of a district cooling system in Sundsvall. The main source for the cooling will be cool water drawn from the aquifer and a compressor chiller. The main purpose of this project has both been to provide the optimal supply temperature of the cooling network at different outdoor temperatures, and to find out to what extent the cool water from the aquifer can be used by itself as the cooling source. The project was initially focused on examining the climate and cooling demand in Sundsvall. The cooling demand was examined on the basis of six existing buildings that uses freshwater district cooling, and different types of climatesystems were then examined to ascertain what their requirements for the supply temperature are. Cooling coil batteries were found to be the component that requires the lowest supply temperature; therefore, the cooling power calculations were relied on them. The outcome of the cooling coil battery calculations was presumed to correspond to the cooling power of the network itself. By comparing the cooling power of the coil batteries at different supply temperatures and the cooling demand at different outdoor temperatures the main supply temperature for the district cooling network took shape. The aquifer is expected to maintain a temperature of approximately 7°C to 9°C, but in this project the temperature is set to exactly 9°C. On those premises the supply temperature of the cooling network could be set to 11°C for most of the year, but with a reduction of the supply temperature at outdoor temperatures around 21°C. Subsequently the supply temperature is reduced to 6°C at the outdoor temperature 25°C. Via the supply temperature curve, the aquifer cooling coverage ratio could be assessed. The result shows that if the supply temperature is raised between 0,5°C and 1,0°C in the distribution network the compressor chiller will have to be in operation for 159 hours per year. If instead the supply temperature is raised 1,5°C or 2,0°C, the compressor chiller must be in operation for 233 hours and 325 hours, respectively. In summary, all the goals and targets of the project have been completed.

A determinação direta de arsênio total em águas por espectrometria de absorção atômica com filamentos de tungstênio (150 W) modificados quimicamente com irídio ou ródio, representa uma alternativa para a atomização eletrotérmica de arsênio, que foi avaliada na presente dissertação. A utilização do revestimento com Ir como modificador químico proporcionou um aumento da massa característica de arsênio de 3,5 vezes. As medidas foram feitas com altura de observação selecionada para proporcionar a melhor razão sinal/ruído sem diminuir a sensibilidade do sinal analítico. Avaliaram-se dois programas de aquecimento: com temperatura de secagem constante (com diminuição gradativa da tensão aplicada) e com temperatura de secagem variável (com tensão aplicada de maneira constante). Não houve diferença na sensibilidade entre os dois programas estudados, indicando que a modificação química leva à formação de um precursor atômico com estabilidade térmica elevada. De fato, utilizando-se a modificação química permanente com 1000 müg Ir, e adotando-se programa de aquecimento com temperatura de secagem variável, a temperatura máxima de pirólise foi de aproximadamente 1700 °C ( temperatura de atomização de 2700 °C). Avaliou-se o comportamento eletrotérmico do As na presença dos concomitantes Na, K, Ca e Mg em 0,1% v/v HNO3. Interferências mais severas foram observadas na presença de cálcio acima de 10 \'mü\'g l-1, e acima de 100 \'mü\'g l-1 para os demais concomitantes. As interferências podem estar relacionadas com o elevado gradiente de temperatura entre a superfície do filamento e a fase gasosa do volume de observação, ou mesmo devido à formação de compostos refratários, particularmente para Ca e Mg, na fase condensada, ou seja, na superfície do atomizador. O emprego do método das médias móveis no tratamento dos sinais transientes gerados na atomização do arsênio também foi avaliada. Com o filamento posicionado na altura de observação 2 mm, foram utilizados os fatores 0, 3, 5, 7 e 9, observando-se melhora considerável nos limites de detecção instrumental e do método,utilizando-se média móvel com fator 7. Nestas condições, e depositando-se 20 \'mü\'l de amostra sobre o filamento, o limite de detecção foi de 3,2 \'mü\'g l-1 As e a massa característica de 37,0 pg As. A exatidão foi avaliada analisando-se diferentes amostras de águas provenientes da região do Quadrilátero Ferrífero do Estado de Minas Gerais, por espectrometria de fluorescência atômica com geração de hidretos e por espectrometria de absorção atômica com o filamento de tungstênio modificado com Ir. A comparação dos resultados mostrou que o método proposto pode ser utilizado para o controle de qualidade de águas desta região. Aproximadamente 150 queimas podem ser feitas com um único filamento de tungstênio / The direct determination of arsenic in waters by atomic absorption spectrometry with 150 W tungsten coils, treated with Ir or Rh, was evaluated as a possible alternative for the eletrothermal atomization of As. The use of iridium as a permanent chemical modifier did improve the characteristic mass of arsenic by 3.5 fold. Measurements were made by choosing an appropriate observation height in order to get the best signal to noise ratio. Two heating programs were tested, either by keeping the applied voltage constant or by using an inverted voltage ramp during the drying step. There were no significant differences in the sensitivities between both heating programs, indicating that the permanent modification lead to the formation of an atomic precursor of high thermal stability. Indeed, with the permanent chemical modification with 1000 \'mü\'g Ir, the maximum pyrolysis temperature was approximately 1700 °C (atomization temperature 2700 °C), allowing a heating program with temperature variation during the drying step. Method selectivity was carried out by evaluating the eletrothermal behavior of As in the presence of up to 1000 \'mü\'g l-1 Na, K, Ca and/or Mg in 0,1% v/v HNO3. The most serious interferences were observed with Ca in concentrations higher than 10 \'mü\'g l-1 and when the concentrations were higher than 100 \'mü\'g l-1 for Na, K or Mg, which can be attributed either to the gradient of temperature between the surface of the atomizer and the observation volume or to the formation of refractory compounds in the condensed phase, particularly with Ca and Mg. The absorbance transient signals treatment by the method of moving averages up to factor 9 was also evaluated, with a remarkable improvement in the instrumental and method detection limits. With the center of the observation volume 2 mm above the tungsten coil surface, and a moving average of factor 7, the limit of detection was 3,2 \'müg\' l-1 As and the characteristic mass 37,0 pg As. Accuracy was evaluate by analysing water samples collected in a contaminated area from the Quadrilátero Ferrífero, Minas Gerais State, by hydride generation atomic fluorescence spectrometry and by tungsten coil eletrothermal atomic absorption spectrometry. Results showed that the proposed method fits for the purpose of CONAMA 357 regulation for drinking water quality in the aforementioned contaminated area. Approximately 150 firings can be done with a single tungsten coil atomizer by using 20 \'mü\'l sample volume

A estimulação magnética transcraniana (EMT) aplicada com diferentes orientações da bobina causa variações na amplitude e na latência dos potenciais evocados motores (PEM) dos músculos da mão. No entanto, as propriedades dos PEM são afetadas também pelos sistemas de detecção, e.g. localização e tamanho dos eletrodos de aquisição, e pela anatomia do músculo analisado, e.g. arquitetura dos tecidos muscular e adiposo. Neste estudo, verificamos como variam a distribuição espacial, a amplitude pico a pico, a latência, a velocidade de condução da fibra muscular e a frequência mediana do espectro de potência dos PEM em função da orientação da bobina de EMT. Utilizamos uma matriz bidimensional de eletrodos de superfície (grade com 13 linhas e 5 colunas) para aquisição do sinal de eletromiografia de superfície (EMGs) do músculo abdutor curto do polegar (ACP) em oito orientações da bobina de EMT em relação à linha sagital, que conecta o ínio ao násio. Duas abordagens distintas foram adotadas para comparação da amplitude em função da orientação da bobina: na primeira abordagem, calculamos a amplitude pico a pico média dos PEM compreendidos em uma região ativa do músculo localizada espacialmente a partir da matriz de EMGs, na segunda abordagem extraímos a amplitude do PEM no sinal diferencial de dois grupos de eletrodos simulando um sistema de EMGs em configuração bipolar, comumente utilizado nos procedimentos em EMT. Em ambos os métodos, identificamos amplitudes máximas para orientações da bobina em ângulos de 45° e 90°, corroborando os achados da literatura. A latência, frequência mediana e velocidade de condução dos PEM não apresentaram variações significativas com a orientação da bobina. Os mapas de distribuição espacial dos PEM indicam uma atividade muscular localizada na porção distal do músculo ACP para todos os ângulos de aplicação da EMT, demonstrando que os eletrodos convencionais de EMGs podem não estar idealmente localizados sobre a região do músculo ativada pela EMT. Por fim, identificamos que um sistema de neuronavegação pode facilitar a localização da estrutura cerebral a ser estimulada e aumentar a precisão no posicionamento da bobina. Adicionamos uma ferramenta para cálculo da orientação da bobina em função da linha sagital média de cada sujeito ao neuronavegador InVesalius Navigator, a ser utilizado nos próximos experimentos. / Transcranial magnetic stimulation (TMS) pulses with different coil orientations causes changes in amplitudes and latencies of motor evoked potentials (MEP) in muscles of the hand. Nonetheless, the properties of MEP are also affected by the systems of detection, e.g. placement and size of acquisition electrodes; and by the target muscle anatomy, e.g. architecture of fat and muscles tissues. In this study, we assessed the effect of TMS coil orientation on MEP spatial distribution, peak-to-peak amplitude, latency, conduction velocity of muscle fiber and median frequency, from the abductor pollicis brevis (APB) muscle. A grid of electrodes (13 lines and 5 columns) was used to detect the surface electromyography (sEMG) signals from the APB at eight different TMS coil orientations in respect to the midsagital line, connecting the inium and nasium. Two distinct approaches were adopted to compare the amplitude according to the coil orientation: first, we calculated the mean amplitude of MEP in the electrodes of the matrix over an active region of the muscle. Second, we extracted the amplitude of MEP in a single differential signal from two groups of matrix electrodes simulating a conventional sEMG bipolar configuration, commonly used in TMS experiments. In both cases, the maximum MEP amplitudes were induced at coil orientations of 45° and 90°, confirming the past findings in literature. However, we could not identify significant differences in latency, median frequency and conduction velocity of MEP according to different stimulus orientation. Maps of spatial distribution showed a localized muscle activity at the distal portion of the APB muscle for all the coil orientations, indicating that conventional bipolar sEMG electrodes may not be rightly placed over the active portion of the muscle recruited by TMS. Finally, we considered that a neuronavigation system could facilitate the localization of brain internal structures to apply TMS stimulus and improve the accuracy of coil handling and positioning over the stimulation point. Thereafter, we developed a computational tool to the InVesalius Navigator, to track the TMS coil position and orientation in respect to the subjects midsagital line to be used in future experiments.

Le travail effectué dans cette thèse a pour thème central la conception d’un aimant quadripolaire supraconducteur en Nb-Ti destiné à remplacer à l’horizon 2014 les aimants d’insertions actuellement utilisés dans le grand collisionneur de Hadrons (LHC) du CERN de Genève. Ce nouveau quadripôle, caractérisé par un diamètre d’ouverture encore jamais atteint (120 mm), ouvre la voie vers les quadripôles à grandes ouvertures. Tout d’abord, pour rapidement estimer l’énergie magnétique stockée dans un quadripôle de type cos2?, une formule analytique basée sur la décomposition en série de Fourier du courant et permettant d’estimer l’énergie avec une précision de 10 % est développée. Le design magnétique de la section transverse de la bobine du quadripôle est ensuite réalisé en utilisant une nouvelle méthode d’optimisation basée sur les équations analytiques du champ magnétique. Puis, pour la première fois, une estimation de la reproductibilité dans le positionnement des blocs de conducteurs dans des aimants Nb3Sn est faite. Elle a été réalisée à l’aide d’une méthode existante et grâce à la production récente de deux séries d’aimants Nb3Sn. Une comparaison avec les valeurs obtenues pour des aimants en Nb-Ti est présentée. Ensuite, une méthode analytique basée sur les statistiques et permettant d’expliquer certains phénomènes observés sur la dispersion des mesures magnétiques dans une série de quadripôles est développée. Enfin, on montre que l’incertitude sur la moyenne des harmoniques de champ est due pour la majorité des harmoniques à un phénomène statistique lié au nombre limité d’aimants dans la série et non à des erreurs systématiques / The main objective of the work presented in this thesis is the design of a quadrupole magnet based on Nb-Ti. It aims at replacing the current insertion quadrupoles used in the Large Hadron Collider (LHC) at CERN by 2014. This new quadrupole features an unprecedented large aperture (120 mm) and opens the way toward large aperture quadrupoles. First, to rapidly estimate the magnetic energy stored in a cos2?-type quadrupole, an analytical formula based on the Fourier transform of the current is developed. It allows estimating the energy with a precision of 10 %. Secondly, the magnetic design of the quadrupole coil cross-section is realized using a novel optimization method based on analytical equations of the magnetic field. Subsequently, for the first time, an estimate of the reproducibility in the coil-blocks positioning in Nb3Sn magnets is given. The estimate has been obtained by using an existing method and from tow recently built Nb3Sn magnet series. A comparison with values obtained for Nb-Ti magnets is also presented. Following this, an analytical method based on statistics is developed. It makes possible to explain some phenomenon observed on the dispersion of the magnetic measurement in a quadrupole series. Finally, we show that the uncertainty in the mean of the magnetic field errors is for most of the harmonics related to statistical errors due to the limited number of magnets in the series, and not because of systematic defects in the coil

A literatura corrente possui informações limitadas sobre o projeto da área de troca térmica de tanques com jaqueta, serpentina helicoidal, serpentina espiral e chicana tubular vertical, em operação com fluidos não-Newtonianos. A presente tese teve por objetivo principal analisar a transferência de calor, potência consumida e ampliação de escala em tanques com impulsores mecânicos na agitação de fluidos não-Newtonianos com duas superfícies de transmissão de calor, chicana tubular vertical e serpentina em espiral. O trabalho também visou fornecer métodos de ampliação de escala de tanques com agitação para fluidos não-Newtonianos que sigam o modelo reológico da lei das potências. A unidade experimental contemplou dois tanques de acrílico, com volume de 10 litros e 50 litros, respectivamente, chicanas tubulares verticais e serpentina em espiral. Os impulsores mecânicos utilizados foram o axial com 4 pás inclinadas a 45° e o radial turbina com 6 pás planas. Como fluidos utilizaram-se soluções aquosas de carboximetilcelulose (0,5%, 1,0% e 1,5%), solução aquosa de carbopol 940 (1,5%), solução aquosa de sacarose (50%) e água. Todos os experimentos foram conduzidos em batelada. Com os dados obtidos, empregou-se o uso de regressões para a obtenção da Equação de Nusselt, as quais forneceram valores de coeficiente de determinação ajustados entre 0,83 e 0,89 com Reynolds no intervalo de 20 a 405000, Prandtl na faixa de 4 a 6400 e índice reológico do modelo da lei das potências entre 0,45 e 1,00. Observou-se que no aquecimento realizado com a chicana tubular vertical, o impulsor radial forneceu coeficientes de convecção 20% acima quando comparado com o impulsor axial, entretanto o consumo de potência foi cerca de 66% maior em relação ao impulsor axial. No caso da serpentina espiral, o impulsor axial promoveu coeficientes de convecção por volta de 15% superiores em relação ao impulsor radial com um consumo de potência 65% menor. Desse modo, em processos em que não é necessária uma elevada turbulência, recomenda-se o uso do impulsor axial com a serpentina espiral, porém, se o processo demandar uma turbulência significativa, deve-se usar o impulsor radial com a chicana tubular vertical. Em uma última análise, os modelos não-lineares obtidos para ampliação de escala forneceram erros entre 11% e 20% na predição da rotação no tanque industrial, os quais são válidos para Reynolds modificados de Metzner e Otto (1957) na faixa de 20 a 4000 e para fluidos não-Newtonianos pseudoplásticos com índices reológicos entre 0,45 e 1,00. / Current literature has limited information on the design of the thermal exchange area of tanks with jacket, helical coil, spiral coil and vertical tuber baffle, in operation with non-Newtonian fluids. The main purpose of this thesis was to analyze heat transfer, power consumption and scale-up in tanks with mechanical impellers in the agitation of non-Newtonian fluids with two heat transfer surfaces, vertical tube baffle and spiral coil. The work also aimed to provide methods of scale-up tank scale with agitation for non-Newtonian fluids that follow the rheology model of the law of powers. The experimental unit included two acrylic tanks, with a volume of 10 liters and 50 liters, respectively, vertical tube baffles and spiral coil. The mechanical impellers used were the 45° pitched blade turbine (PBT) and the Rushton turbine (RT). Aqueous solutions of carboxymethylcellulose (0.5%, 1.0% and 1.5%), aqueous solution of carbopol 940 (1.5%), aqueous solution of sucrose (50%) and water were used as fluids. All the experiments were conducted in batch. With the obtained data, we used the regressions to obtain the Nusselt Equation, which provided coefficient of determination values adjusted between 0.83 and 0.89 with Reynolds in the range of 20 to 405000, Prandtl in the range of 4 to 6400 and rheological index of the power law model between 0.45 and 1.00. It was observed that in the heating performed with the vertical tube baffle, the RT provided convection coefficients 20% higher when compared to the axial impeller, however the power consumption was about 66% higher in relation to the PBT. In the case of the spiral coil, the PBT promoted convection coefficients around 15% higher than the RT with 65% lower power consumption. Thus, in processes where high turbulence is not required, it is recommended to use the PBT with the spiral coil, but if the process requires significant turbulence, the RT must be used with the vertical tubular chassis. In a final analysis, the nonlinear models obtained for scaling provided errors between 11% and 20% in the prediction of rotation in the industrial tank, which are valid for Metzner and Otto (1957) modified Reynolds in the range of 20 to 4000 and for non-Newtonian pseudoplastic fluids with rheological indexes between 0.45 and 1.00.

A determinação direta de arsênio total em águas por espectrometria de absorção atômica com filamentos de tungstênio (150 W) modificados quimicamente com irídio ou ródio, representa uma alternativa para a atomização eletrotérmica de arsênio, que foi avaliada na presente dissertação. A utilização do revestimento com Ir como modificador químico proporcionou um aumento da massa característica de arsênio de 3,5 vezes. As medidas foram feitas com altura de observação selecionada para proporcionar a melhor razão sinal/ruído sem diminuir a sensibilidade do sinal analítico. Avaliaram-se dois programas de aquecimento: com temperatura de secagem constante (com diminuição gradativa da tensão aplicada) e com temperatura de secagem variável (com tensão aplicada de maneira constante). Não houve diferença na sensibilidade entre os dois programas estudados, indicando que a modificação química leva à formação de um precursor atômico com estabilidade térmica elevada. De fato, utilizando-se a modificação química permanente com 1000 müg Ir, e adotando-se programa de aquecimento com temperatura de secagem variável, a temperatura máxima de pirólise foi de aproximadamente 1700 °C ( temperatura de atomização de 2700 °C). Avaliou-se o comportamento eletrotérmico do As na presença dos concomitantes Na, K, Ca e Mg em 0,1% v/v HNO3. Interferências mais severas foram observadas na presença de cálcio acima de 10 \'mü\'g l-1, e acima de 100 \'mü\'g l-1 para os demais concomitantes. As interferências podem estar relacionadas com o elevado gradiente de temperatura entre a superfície do filamento e a fase gasosa do volume de observação, ou mesmo devido à formação de compostos refratários, particularmente para Ca e Mg, na fase condensada, ou seja, na superfície do atomizador. O emprego do método das médias móveis no tratamento dos sinais transientes gerados na atomização do arsênio também foi avaliada. Com o filamento posicionado na altura de observação 2 mm, foram utilizados os fatores 0, 3, 5, 7 e 9, observando-se melhora considerável nos limites de detecção instrumental e do método,utilizando-se média móvel com fator 7. Nestas condições, e depositando-se 20 \'mü\'l de amostra sobre o filamento, o limite de detecção foi de 3,2 \'mü\'g l-1 As e a massa característica de 37,0 pg As. A exatidão foi avaliada analisando-se diferentes amostras de águas provenientes da região do Quadrilátero Ferrífero do Estado de Minas Gerais, por espectrometria de fluorescência atômica com geração de hidretos e por espectrometria de absorção atômica com o filamento de tungstênio modificado com Ir. A comparação dos resultados mostrou que o método proposto pode ser utilizado para o controle de qualidade de águas desta região. Aproximadamente 150 queimas podem ser feitas com um único filamento de tungstênio / The direct determination of arsenic in waters by atomic absorption spectrometry with 150 W tungsten coils, treated with Ir or Rh, was evaluated as a possible alternative for the eletrothermal atomization of As. The use of iridium as a permanent chemical modifier did improve the characteristic mass of arsenic by 3.5 fold. Measurements were made by choosing an appropriate observation height in order to get the best signal to noise ratio. Two heating programs were tested, either by keeping the applied voltage constant or by using an inverted voltage ramp during the drying step. There were no significant differences in the sensitivities between both heating programs, indicating that the permanent modification lead to the formation of an atomic precursor of high thermal stability. Indeed, with the permanent chemical modification with 1000 \'mü\'g Ir, the maximum pyrolysis temperature was approximately 1700 °C (atomization temperature 2700 °C), allowing a heating program with temperature variation during the drying step. Method selectivity was carried out by evaluating the eletrothermal behavior of As in the presence of up to 1000 \'mü\'g l-1 Na, K, Ca and/or Mg in 0,1% v/v HNO3. The most serious interferences were observed with Ca in concentrations higher than 10 \'mü\'g l-1 and when the concentrations were higher than 100 \'mü\'g l-1 for Na, K or Mg, which can be attributed either to the gradient of temperature between the surface of the atomizer and the observation volume or to the formation of refractory compounds in the condensed phase, particularly with Ca and Mg. The absorbance transient signals treatment by the method of moving averages up to factor 9 was also evaluated, with a remarkable improvement in the instrumental and method detection limits. With the center of the observation volume 2 mm above the tungsten coil surface, and a moving average of factor 7, the limit of detection was 3,2 \'müg\' l-1 As and the characteristic mass 37,0 pg As. Accuracy was evaluate by analysing water samples collected in a contaminated area from the Quadrilátero Ferrífero, Minas Gerais State, by hydride generation atomic fluorescence spectrometry and by tungsten coil eletrothermal atomic absorption spectrometry. Results showed that the proposed method fits for the purpose of CONAMA 357 regulation for drinking water quality in the aforementioned contaminated area. Approximately 150 firings can be done with a single tungsten coil atomizer by using 20 \'mü\'l sample volume