[pt] Os sistemas de potência são projetados para operarem com tensão e freqüência constantes, admitindo-se pequenas variações em torno de sues valores nominais. Estas grandezas são controladas principalmente pelos sistemas de excitação e reguladores de velocidade, respectivamente. Esta dissertação examina o projeto de sistemas de excitação modernos e estabelece as características de projeto dos componentes das excitatrizes estáticas. Os principais componentes (conversor, circuito de disparo, circuito de partida e regulador de tensão) são implementados em um protótipo de excitatriz. As respostas do protótipo à pequenas e grandes perturbações também são discutidas. / [en] Power systems are designed to operate with constant voltagem and frequency, allowing small sinal variations around its rated valves. These quantities are mainly controlled by excitation systems and governors, respectively. This dissertation examines the design of modern excitation systems and estabilishes the desired characteristics of static exciter componentes. The main components (conversor, firing circuit, starting circuit and voltage regulator) are implemented in a exciter prototype. The prototype response to small and larger disturbances are also discussed.

No description available.

Structural Health Monitoring (SHM) is a process of implementing a damage identification procedure for mechanical, aerospace and civil engineering infrastructure. Any change in the geometric properties, boundary conditions and behavior of material is defined as damage of these systems. In the past 10 years, there has been an accelerated increase in the amount of research related to SHM [1]. Hence, the increased interest in SHM to a wide range of industries and its correlated capability for significant life-safety and economic benefits has motivated the need for this thesis topic. The objective of this thesis study was to explore SHM approach to monitor and detect a change and/or damage in plates using Lamb wave propagation and surface response to excitation. First, the endurance of sensors and the adhesive used was evaluated. Next, the experimental data from the prepared samples was collected, compared, and evaluated. The obtained results indicated the severity and location of the defects.

No description available.

Background-In cardiomyocytes from patients with hypertrophic cardiomyopathy, mechanical dysfunction and arrhythmogenicity are caused by mutation-driven changes in myofilament function combined with excitation-contraction (E-C) coupling abnormalities related to adverse remodeling. Whether myofilament or E-C coupling alterations are more relevant in disease development is unknown. Here, we aim to investigate whether the relative roles of myofilament dysfunction and E-C coupling remodeling in determining the hypertrophic cardiomyopathy phenotype are mutation specific. Methods and Results-Two hypertrophic cardiomyopathy mouse models carrying the R92Q and the E163R TNNT2 mutations were investigated. Echocardiography showed left ventricular hypertrophy, enhanced contractility, and diastolic dysfunction in both models; however, these phenotypes were more pronounced in the R92Q mice. Both E163R and R92Q trabeculae showed prolonged twitch relaxation and increased occurrence of premature beats. In E163R ventricular myofibrils or skinned trabeculae, relaxation following Ca2+ removal was prolonged; resting tension and resting ATPase were higher; and isometric ATPase at maximal Ca2+ activation, the energy cost of tension generation, and myofilament Ca2+ sensitivity were increased compared with that in wildtype mice. No sarcomeric changes were observed in R92Q versus wild-type mice, except for a large increase in myofilament Ca2+ sensitivity. In R92Q myocardium, we found a blunted response to inotropic interventions, slower decay of Ca2+ transients, reduced SERCA function, and increased Ca2+/calmodulin kinase II activity. Contrarily, secondary alterations of E-C coupling and signaling were minimal in E163R myocardium. Conclusions-In E163R models, mutation-driven myofilament abnormalities directly cause myocardial dysfunction. In R92Q, diastolic dysfunction and arrhythmogenicity are mediated by profound cardiomyocytesignaling and E-C coupling changes. Similar hypertrophic cardiomyopathy phenotypes can be generated through different pathways, implying different strategies for a precision medicine approach to treatment.

Light-matter interactions lead to a variety of interesting phenomena, for example photosynthesis which is a process fundamental to life on earth. There exists many different spectroscopic methods to measure light-matter interactions, for example UV/Vis spectroscopy, that can provide information about electronically excited states. However, numerical methods and theory are important to model and gain understanding of these experiments. Quantum chemistry provides that understanding, giving the possibility to numerically calculate molecular properties like excitation energies. The aim of this thesis was to implement a reduced-space algorithm in Dalton, to solve an eigenvalue equation obtained by response theory, for the calculation of excitation energies of molecular systems. There already was a similar algorithm in Dalton, that was able to perform these calculations. However, in a different module of Dalton used mainly for complex response theory, an algorithm to obtain eigenvalues was missing. The new implementation was similar to the existing one, except for the division of the reduced space into even and odd parts used in the complex response module. The thesis starts with a quick introduction of light-matter interactions and proceeds with a description of many-body theory, including numerical methods used in that field. In the end of the theoretical part, the eigenvalue equation, used to calculate excitation energies, is derived. In the following section, the reduced-space algorithm is described. In the end of the thesis, numerical results obtained with the algorithm are presented, including a small basis set and method study. The comparison with the existing implementation of the similar algorithm verified the successful implementation of the algorithm presented in this thesis.

>Magister Scientiae - MSc / This thesis aims at developing a sorting code for Coulomb excitation studies at iThemba LABS. In Coulomb excitation reactions, the inelastic scattering of the projectile transfers energy to the partner nucleus (and vice-versa) through a time-dependent electromagnetic field. At energies well below the Coulomb barrier, the particles interact solely through the well known electromagnetic interaction, thereby excluding nuclear excitations from the process . The data can therefore be analyzed using a semiclassical approximation. The sorting code was used to process and analyze data acquired from the Coulomb excitation of 20Ne beams at 73 and 96 MeV, onto a 194Pt target. The detection of gamma rays was done using the AFRODITE HPGe clover detector array, which consists of nine clover detectors, in coincidence with the 20Ne particles detected with an S3 double-sided silicon detector. The new sorting code includes Doppler-correction effects, charge-sharing, energy and time conditions, kinematics and stopping powers, among others, and can be used for any particle-γ coincidence measurements at iThemba LABS. Results from other Coulomb excitation measurements at iThemba LABS will also be presented.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21593号 / 理博第4500号 / 新制||理||1646(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 林 重彦, 教授 谷村 吉隆, 教授 寺嶋 正秀 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22301号 / 医博第4542号 / 新制||医||1040(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 渡邊 直樹, 教授 椛島 健治, 教授 林 康紀 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

This master’s thesis is focused on the analysis of the excitation current in synchronnous machines. Contains a description of excitation systems for synchronous machines, meaning and design of the sliding contact ant its representation in electrical machines. The main part of the work is focused on the evaluation of the field current of the three plants. The work includes graphic record of the excitation current of the hydroelectric power station Slapy, provided record from the power plant Opatovice was for evaluating load of turbo-generators. Provided record from the nuclear power plant Temelín was for evaluating.current division into individual brushes. The conclusion is a summary of the achieved knowledge.