Obesity is nowadays one of the very topics discussed as a highly serious health problem. This thesis is concerned with the percentage of body fat have student teachers for 1st Primary Schools Faculty of Education, University of South Bohemia in Czech Budejovice and the results are compared with the survey in 2005. Research underwent 114 students, of which 8 were men and 106 women. Measurements were carried out in the months of May to October of 2011. For measuring device was used OMRON BF 300, which uses the method of bioelectrical impedance of the upper limbs. The results show that, compared with research in 2005 there was a slight increase in percent body fat in women and men.

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As linhas de transmissão são usadas para transmitir energia elétrica por longas distâncias e estão naturalmente expostas a condições climáticas severas e à ocorrência de faltas, especialmente as linhas aéreas. Estatísticas mostram que entre 70% - 90% das faltas em linhas de transmissão aéreas são momentâneas (ou transitórias) e apresentam formação de arco elétrico. O arco elétrico é a principal característica de uma falta de alta impedância e resulta do pobre contato entre um condutor energizado e a superfície envolvida. Esta tese aborda o problema de localização de faltas de alta impedância em linhas de transmissão curtas. Propõese uma nova técnica de localização de faltas de alta impedância baseada na impedância aparente, desenvolvida no domínio da frequência e que utiliza componentes de fase. A estimativa da distância da falta é obtida a partir da solução de um sistema sobredeterminado de equações lineares, obtida pela aplicação do método de mínimos quadrados. A abordagem proposta permite estimar a distância de faltas de alta impedância momentâneas e permanentes, em linhas de transmissão curtas simples e paralelas, transpostas ou não. O desempenho da técnica de localização de faltas proposta é avaliado mediante estudos de casos simulados no Alternative Transients Program (ATP) considerando análises de sensibilidade e comparativa, bem como casos reais de faltas. Os resultados obtidos, considerando faltas de alta impedância simuladas e reais, indicam claramente que a abordagem proposta possui validade como técnica de localização de faltas em linhas de transmissão curtas em decorrência do desempenho demonstrado e, também, por características tais como: formulação simplificada no domínio da frequência, simplicidade e facilidade de implementação em dispositivos reais e aplicabilidade a casos reais. / Transmission lines are used to transmit electric power over long distances and are naturally exposed to severe weather conditions, especially overhead lines. Such conditions are highly favorable to the occurrence of faults. Statistics show that between 70% - 90% of faults on overhead lines are nonpermanent (or transient), and present arcing. Arcing is the main characteristic of a nonlinear high impedance fault and is the result of poor contact between an energized conductor and the ground or a grounded object. This thesis approaches the high impedance fault location on short transmission lines problem. It is proposed an impedancebased nonlinear high impedance fault location formulation developed in frequency domain and phase components. The formulation uses the least square method and synchronized phasors, measured by, for example, digital fault recorders installed at both line terminals. The proposed approach allows to estimate the distance of high impedance momentary and permanent faults on short transposed or untransposed transmission lines. The performance of the proposed fault location approach is evaluated through analysis of simulated cases in the Alternative Transients Program (ATP) considering sensitivity and comparative analyzes, and actual cases of high impedance faults. The results, considering simulations of high impedance faults and actual cases, indicate clearly that the proposed approach is valid as fault location technique in short transmission lines due to the demonstrated performance.

abstract: High Impedance Surfaces (HISs), which have been investigated extensively, have proven to be very efficient ground planes for low profile antenna applications due to their unique reflection phase characteristics. Another emerging research field among the microwave and antenna technologies is the design of flexible antennas and microwave circuits to be utilized in conformal applications. The combination of those two research topics gives birth to a third one, namely the design of Conformal or Flexible HISs (FHISs), which is the main subject of this dissertation. The problems associated with the FHISs are twofold: characterization and physical realization. The characterization involves the analysis of scattering properties of FHISs in the presence of plane wave and localized sources. For this purpose, an approximate analytical method is developed to characterize the reflection properties of a cylindrically curved FHIS. The effects of curvature on the reflection phase of the curved FHISs are examined. Furthermore, the effects of different types of currents, specifically the ones inherent to finite sized periodic structures, on the reflection phase characteristics are observed. After the reflection phase characterization of curved HISs, the performance of dipole antennas located in close proximity to a curved HIS are investigated, and the results are compared with the flat case. Different types of resonances that may occur for such a low-profile antenna application are discussed. The effects of curvature on the radiation performance of antennas are examined. Commercially available flexible materials are relatively thin which degrades the bandwidth of HISs. Another practical aspect, which is related to the substrate thickness, is the compactness of the surface. Because of the design limitations of conventional HISs, it is not possible to miniaturize the HIS and increase the bandwidth, simultaneously. To overcome this drawback, a novel HIS is proposed with a periodically perforated ground plane. Copper plated through holes are extremely vulnerable to bending and should be avoided at the bending parts of flexible circuits. Fortunately, if designed properly, the perforations on the ground plane may result in suppression of surface waves. Hence, metallic posts can be eliminated without hindering the surface wave suppression properties of HISs. / Dissertation/Thesis / Ph.D. Electrical Engineering 2013

As linhas de transmissão são usadas para transmitir energia elétrica por longas distâncias e estão naturalmente expostas a condições climáticas severas e à ocorrência de faltas, especialmente as linhas aéreas. Estatísticas mostram que entre 70% - 90% das faltas em linhas de transmissão aéreas são momentâneas (ou transitórias) e apresentam formação de arco elétrico. O arco elétrico é a principal característica de uma falta de alta impedância e resulta do pobre contato entre um condutor energizado e a superfície envolvida. Esta tese aborda o problema de localização de faltas de alta impedância em linhas de transmissão curtas. Propõese uma nova técnica de localização de faltas de alta impedância baseada na impedância aparente, desenvolvida no domínio da frequência e que utiliza componentes de fase. A estimativa da distância da falta é obtida a partir da solução de um sistema sobredeterminado de equações lineares, obtida pela aplicação do método de mínimos quadrados. A abordagem proposta permite estimar a distância de faltas de alta impedância momentâneas e permanentes, em linhas de transmissão curtas simples e paralelas, transpostas ou não. O desempenho da técnica de localização de faltas proposta é avaliado mediante estudos de casos simulados no Alternative Transients Program (ATP) considerando análises de sensibilidade e comparativa, bem como casos reais de faltas. Os resultados obtidos, considerando faltas de alta impedância simuladas e reais, indicam claramente que a abordagem proposta possui validade como técnica de localização de faltas em linhas de transmissão curtas em decorrência do desempenho demonstrado e, também, por características tais como: formulação simplificada no domínio da frequência, simplicidade e facilidade de implementação em dispositivos reais e aplicabilidade a casos reais. / Transmission lines are used to transmit electric power over long distances and are naturally exposed to severe weather conditions, especially overhead lines. Such conditions are highly favorable to the occurrence of faults. Statistics show that between 70% - 90% of faults on overhead lines are nonpermanent (or transient), and present arcing. Arcing is the main characteristic of a nonlinear high impedance fault and is the result of poor contact between an energized conductor and the ground or a grounded object. This thesis approaches the high impedance fault location on short transmission lines problem. It is proposed an impedancebased nonlinear high impedance fault location formulation developed in frequency domain and phase components. The formulation uses the least square method and synchronized phasors, measured by, for example, digital fault recorders installed at both line terminals. The proposed approach allows to estimate the distance of high impedance momentary and permanent faults on short transposed or untransposed transmission lines. The performance of the proposed fault location approach is evaluated through analysis of simulated cases in the Alternative Transients Program (ATP) considering sensitivity and comparative analyzes, and actual cases of high impedance faults. The results, considering simulations of high impedance faults and actual cases, indicate clearly that the proposed approach is valid as fault location technique in short transmission lines due to the demonstrated performance.

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In this thesis we introduce a two-way Doherty amplifier architecture with multiple feedbacks for digital predistortion based on impedance-inverting directional coupler (transcoupler). The tunable two-way Doherty amplifier with a tuned circulator-based impedance inverter is presented. Compact N-way Doherty architectures that subsume impedance inverter and offset line functionality into output matching networks are derived. Comprehensive N-way Doherty amplifier design and analysis techniques based on load-pull characterization of active devices and impedance modulation effects are developed. These techniques were then applied to the design of a two-way Doherty amplifier and a three-way Doherty amplifier which were manufactured and their performance measured and compared to the amplifier performance specifications and simulated results.

Quality control is essential in food industry and efficient quality assurance is becoming increasingly important. The assessment of food quality still centers on its sensory properties (appearance, aroma and texture). Bread is one of the most consumed food item all over the world. Bakery product manufacturers expect that the bread should retain all of its attributes during storage and consumers expect their bread to be ‘fresh’. Unfortunately, it remains truly ‘fresh’ for only a few hours after it leaves the oven because the ingredients of the bread undergo series of physical and chemical changes that eventually lead to deterioration, referred as “staling”, of bread quality. Bread staling is classified in two categories: crust (outer portion of bread) staling and crumb (center portion of bread) staling. Crust staling is associated to the moisture migration from crumb to crust during storage. This moisture migration leads to a phenomenon called glass transition at crust. This phenomenon changes the mechanical and dielectric properties of bread crust. Crumb staling is mainly associated to the physicochemical changes in starch. During storage, amorphous starch regains its crystallinity, which increases the firmnesss and dryness of bread crumb. Thus, the knowledge of moisture content, starch recrystallization and the glass transition helps in understanding the bread staling mechanism. There are some volatiles produced from the bread during storage, which forms the characteristic flavor or aroma of the bread. The loss of this characteristic flavor during storage also gives the information about the loss of freshness and staling. Thus, there is a need for detection and monitoring the loss of these volatiles to determine the characteristic flavor during storage. Hence, the present investigations are focused on these issues and developed a measurement facility to monitor the above physicochemical changes in bread during storage. As a part of experimental investigations, two separate test facilities have been developed. A multichannel ring electrodes with suitable instrumentation based on impedance spectroscopy technique is developed for simultaneous measurement of electrical properties of bread at crust and crumb during storage in the frequency range from 50 Hz to 100 kHz. The detailed investigations have been conducted on wheat bread. The variation in capacitance showed that the glass transition phenomenon, at room temperature, in bread crust occurs after 96 h of storage with 18% of moisture in it. The resistance changes at bread crumb showed the starch recrystallization during staling. The electrical property results are justified with the results obtained from the conventional differential scanning calorimmetery (DSC) studies. The impedance measurement at crust and crumb estimates the moisture content at the respective zones of bread. Thus the test facility is used for the simultaneous measurement of moisture content, starch recrystallization and glass transition at crumb and crust respectively without destructing the bread loaf. A few experiments are conducted on maida bread and the obtained results are compared with the wheat bread results. Another test facility has been developed for the detection of volatiles produced from the wheat bread during storage. The gas chromatography and mass spectroscopy (GC-MS) experimentations are conducted to identify the volatiles produced from the bread during storage. The major volatiles produced from wheat bread are found to be 1-Heptanol, 1-Pentanol, 1-Octanol, Furan and Hydroperoxyde. A conducting polymer based gas sensor is designed and developed to sense these volatiles and the changes in its electrical property is monitored with a suitable instrumentation based on impedance spectroscopy technique in the frequency range from 10 Hz to 2MHz. Experimental investigations are carried out in an in-house air tight closed test chamber. The bread sample and the designed sensor are kept inside the test chamber and closed tightly so that only bread volatile can interact with the sensor. The sensor response is monitored by measuring the changes in its capacitance upon exposure to organic volatiles produced from bread during storage. It is observed that the capacitance of the sensor changes with the quantitative changes of the above volatiles. Thus, the test facility is found quite suitable for the detection and monitoring the bread volatiles produced during storage, which finally affects the aroma property. Thus, the developed experimental test facilities with suitable sensors and instrumentation based on impedance spectroscopy technique are found quite suitable to monitor the changes in physicochemical properties and aroma of bread during storage. The correlation between the measured electrical properties and the changes in the textural and flavor properties of bread during storage has been established. The results obtained with the developed test facilities are in good agreement with the results obtained from the standard traditional techniques like DSC and GC-MS.

High-temperature piezoelectric wafer active sensors (HT-PWAS) have been developed for structure health monitoring at hazard environments for decades. Different candidates have previously been tested under 270 °C and a new piezoelectric material langasite (LGS) was chosen here for a pilot study up to 700 °C. A preliminary study was performed to develop a high temperature sensor that utilizes langasite material. The Electromechanical impedance (E/M) method was chosen to detect the piezoelectric property. Experiments that verify the basic piezoelectric property of LGS at high temperature environments were carried out. Further validations were conducted by testing structures with attached LGS sensors at elevated temperature. Additionally, a detection system simulating the working process of LGS monitoring system was developed with PZT material at room temperature. This thesis, for the first time, (to the best of author’s knowledge) presents that langasite is ideal for making piezoelectric wafer active sensors for high temperature structure health monitoring applications.

Title: Body composition in patients with idiopatic inflammatory myopathies Objectives: The aim of this study was to compare selected parameters of body composition in patients with idiopathic inflammatory myopathies (IIM) with age- and sex-matched healthy controls (HC). Another objective was to evaluate the effect of selected clinical parameters in patients with IIM on the detectedvariability of the parameters of body composition and on physical activity of patients. Methods: The research sample consisted of 84 individuals (54 IIM, 30 HC). In anthropometry, we measured: body height (cm), weight (kg) and BMI (kg/m2 ). Using bioelectrical impedance analysis BIA 2000-M we obtained values: total body water (TBW in%), muscle mass (LBM in kg), body fat (BF in%) cell mass of lean body mass (BCM of FFM in%), and the proportion of extracellular/intracellular matrix (ECM/BCM). Using Lunar series iDXA we obtained values: muscle mass (LBM in kg), body fat (BF in %), bone mineral density (BMD in g/cm3 ), and visceral fat (Visceral in kg). To these measured values we added a questionnaire on physical activity Human Acitvity Profile (HAP). Statistics: T-test, Mann Whitney U test, Cohen's d, and Partialeta-squared. Results: Selected values (mean ± SD): body height: IIM 164.7 ± 9.1 cm, HC 170.3 ± 7 cm; body weight:...