Für die Optimierung akustischer Eigenschaften von Räumen ist die Verbesserung deren numerischer Simulationen von entscheidender Bedeutung. Im unteren Frequenzbereich hängt in vielen Fällen die Qualität der Lösungen stark von der Kenntnis akustischer Wandadmittanzen ab. Die vorliegende Arbeit umfasst die Entwicklung und Untersuchung verschiedener auf deterministischen Diskretisierungen des akustischen Randwertproblems basierender Formulierungen zur globalen Bestimmung frequenzabhängiger Admittanzparameter. Mit Admittanzen kann das Reflexions- und Absorptionsverhalten von Wänden quantifiziert werden. Der vorgestellte Ansatz der globalen Admittanzbestimmung in Innenräumen ermöglicht die Berücksichtigung schrägen Schalleinfalls. Die Methode sieht ein Experiment vor, bei dem das Schallfeld mit Mikrofonen abgetastet, alle vorhandenen Schallquellen bestimmt sowie die Geometrie des akustischen Raumes erfasst werden. Mit den in der Arbeit entwickelten Algorithmen wird eine globale Admittanzverteilung für den gesamten Rand aus diesen Daten berechnet. Mit Hilfe erfolgreich identifizierter Admittanzverläufe sollen Simulationen niederfrequenter Wellenausbreitungen in Räumen auch komplizierter Geometrien und Oberflächenbeschaffenheiten durch Hinzunahme von Admittanzrandbedingungen ermöglicht und verbessert werden. Die Bestimmung von Wandadmittanzen aus partiell bekannten Schalldruckwerten wird mathematisch als inverses Problem eingeordnet. Für die inversen Algorithmen werden die Methoden der Randelemente (BE) und der finiten Elemente (FE) zur Diskretisierung des akustischen Randwertproblems verwendet. Aus den Gleichungen der BE-Diskretisierung lässt sich ein schlecht konditioniertes, aber dafür lineares Gleichungssystem für das inverse Problem finden, während die FE-basierte Formulierung ein nichtlineares, aufgrund der Komplexität des Problems meist ebenfalls schlecht konditioniertes Optimierungsproblem darstellt. Ein wesentliches Ergebnis dieser Arbeit ist die Gegenüberstellung der linearen und nichtlinearen Algorithmen des inversen Problems in Hinblick auf deren Herleitungen, die umgesetzten Berechnungsverfahren und der sich stark unterscheidenden Lösungsqualitäten. Untersuchungen der Admittanzrekonstruktion an zwei- und dreidimensionalen theoretischen Modellen verdeutlichen die Einflüsse der Modellgenauigkeit, des Messumfanges und des Messrauschens auf die Ergebnisse der inversen Algorithmen. Anhand der Anwendung auf Messdaten eines bei Brüel & Kjaer durchgeführten Experimentes wird das inverse Verfahren der globalen Admittanzbestimmung einem Praxistest unterzogen. / Reflection and absorption of sound waves on boundaries play a determining role for the optimization of acoustical properties in closed rooms. Above all the geometry and dynamic behavior of the wall structure are responsible for it. These boundary terms are quantifiable within the scope of numerical acoustics by the so-called admittance boundary conditions of the acoustical boundary value problem. Especially at low frequencies the quality of acoustical simulation depends strongly on the recognition of boundary admittances. The present work includes the development of two different inverse algorithms based on deterministic discretization methods for the global determination of frequency-dependent boundary admittance parameters. The approach of global determination of admittances allows to take account for non-perpendicular wave incident. For the method to work an experiment shall be initially conducted. In that process all present sound sources and microphone arrays scanning the sound field must be located and measured and a model of the geometry of the room needs to be created. The developed algorithms calculate then a global admittance distribution based on this data. Using successfully identified admittance characteristics as admittance boundary condition, low frequency simulation in rooms of complex geometry and arbitrary consistency of the surface shall be improved. Identifying boundary admittances out of partially measured sound pressure data is classifiable as inverse acoustic problem. In order to develop inverse formulations the acoustical boundary value problem is discretized by means of the Boundary Element and the Finite Element Method. The inverse formulation of the Boundary Element equations composes an ill-posed but linear system of equations. In contrast, based on Finite Elements only a nonlinear optimization problem can be set up that often features a bad condition due to the complexity of the inverse problem. The comparison of these linear and nonlinear algorithms of the inverse acoustic problem of global determination of boundary admittances in respect of derivation, implemented solution techniques and differing solution qualities states an essential result of this work. The investigation of admittance reconstruction at two and three-dimensional theoretical models reveal the influences of model accuracy, measurement expense and noise on measured data onto the results of both inverse algorithms. Finally, the problem of global admittance determination is subjected to experimentally obtained data (at Brüel & Kjaer) in order to check for practical applicability.

Die Anforderungen an schnelle Dioden sind sehr hoch für große Spannungen und große Ströme. Die Beeinflussung des Bauelementverhaltens durch das Design des Dotierprofils mit einem tiefen mehrstufigen Feldstopp aus Selen bildet einen zentralen Punkt der Dissertation. Mit physikalischen Messverfahren werden die in der Literatur nur unzureichend untersuchten Eigenschaften von Selen in Silizium erfasst und als Basis für Bauelementsimulationen verwendet. Für die Untersuchung der Störstelleneigenschaften kommt die klassische aufwändige DLTS zum Einsatz. Des Weiteren werden für diese Untersuchungen die Vorteile der einfacheren frequenzabhängigen Admittanzspektroskopie ausführlich dargelegt. Anhand der Bauelementsimulationen erfolgt ein Vergleich mit Messungen und führt zur Vorstellung und Erläuterung einer verbesserten soften und robusten Diodenstruktur mit tiefen Donatoren aus Selen. / The focus of the following work is the correlation between the field-stop design and the behaviour of high-voltage power diodes. The objective is to present a further improvement of the diode performance using a special field-stop, which optimizes the diode in relation to a soft switching behaviour and an increased robustness. The function of such a field-stop is investigated. Benefits are shown of materials for field-stops with deep impurities in the semiconductor material and of multiple stepped deep field-stop structures. Therefore a central role have silicon diodes with selenium in the field-stop layer. Measurements and simulations with the power device simulator Sentaurus TCAD are done and explain the named correlations. The deep level transient spectroscopy is used as method to analyse the required impurity parameters. Beside this method the evaluation is done by the introduced frequency resolved admittance spectroscopy.

Byggnader i Sverige står för en stor del av landets totala energianvändning och det är därför viktigt att man försöker hitta energieffektiviseringar kring detta område. Ibland kan det vara enklare än man tror att komma på billiga energibesparande lösningar. En självklar sak är att termodynamikens andra lag även gäller avlopp. Eftersom avlopp i hus är öppna system, exponerade mot bistra uteklimatet genom hål eller små skorstenar i taket och det kommunala avloppsystemet, så borde det rimligtvis försvinna värmeenergi från huset även där. Man kan tänka sig att det sker kallras på vintern eller ett luftflöde som drar igenom husets avloppssystem. Detta drag borde kyla ner avloppsystemet. Vi kunde konstatera med hjälp av luftflödesmätare att detta drag på grund av skorstenseffekter ofta är riktat så att det kommer in kall luft från det kommunala avloppssystemet och ut igenom avluftningen på taket. Durgo är ett företag som tillverkar avluftningsventiler. Avluftningsventilen fungerar som så att den bara tar in luft när det blir undertryck i avloppet. Därmed kommer det inte ut någon illaluktande luft från avloppet vilket gör att man kan ha avluftningen installerad inomhus exempelvis på en vind. Om man sätter en avluftningsventil istället för att ha en öppen genomföring via taket sätter man stopp för det drag som kommer från kommunens avloppsnät. Därmed blir det minskad avkylning vid kall väderlek i husets avloppsledningar. Avloppsledningar i hus kan ofta vara oisolerade, även om de kan befinna sig i mer eller mindre isolerade utrymmen så kyler de ner konstruktionen och närliggande rum. Syftet med detta examensarbete är att ta reda på om det går att spara energi med en avluftningsventil. Vi bygger en experimentanläggning för att simulera energiåtgången. Experimentanläggningen består av två isolerade tankar, en luftad med avluftningsventil, den andra med öppen skorsten. Sen gör vi två olika typer av experiment där vi mäter temperaturen i tankarna. Första sättet tittar vi på hur snabbt vatten avkyls i två isolerade tankar där ena tanken är ventilerad som om det vore ett traditionellt avluftat avloppssystem och den andra tanken är ventilerad med en avluftningsventil. Andra sättet jämför vi hur mycket energi det går att upprätthålla en viss temperatur i dessa isolerade tankar. På så sätt kan vi enkelt se om det finns skillnader mellan de olika systemen. Vårt förväntade resultat var att man skulle spara energi om man använde sig av en avluftningsventil. Efter att vi gjort våra experiment kunde man se att vår hypotes mycket väl stämde överens med verkligheten. Vårt experiment visar att ju kallare det är utomhus desto större energibesparing gör man med en avluftningsventil. Energibesparingen kan bli runt 13 kWh per meter avloppsrör och år vilket skulle kunna motsvara 1-2 % per år av den totala uppvärmningskostnaden i ett hus beroende på hur många meter man har. I ett flerbostadshus med 84 lägenheter med 45 % effektgrad av värmeåtervinningen från spillvatten blir energisbesparingen ca 10 000 kWh/år då spillvattentemperaturen höjs med en grad. En avluftningsventil är en mycket billig investering och har dessutom flera andra fördelar än att man sparar energi. Dock måste man tillse att den monteras på rätt sätt så den inte läcker ut avloppsgas. / Buildings in Sweden account for a large proportion of the country’s total energy consumption and it is therefore important to try and find energy efficiencies around this area. Sometimes it can be easier than you think to get cheap energy saving solutions. One obvious thing is that the second law of thermodynamics also applies for sewerage. Because the sewage in houses are open systems, exposed to the harsh outdoor climate through holes or small chimneys on the roof and the municipal sewer system, then it should be reasonable that heat energy disappears from the house too. One could imagine that there are cold drafts in the winter or an airflow that pulls through the building's drainage system. This flow should cool down the drains. We could conclude with the aid of an airflow meter that these flows because of the chimney effects often are directed so that cool air flows from the municipal sewage system and out through the vent on the roof. Durgo is a company that manufactures air admittance valves. This valve works so that it only takes in air when under pressure in the sewer system. Thus, it will not print any foul air from the sewer which means that you can have the vent installed indoors, for example in an attic. If you put an air admittance valve instead of having an opening through the roof you put a stop to this airflow. Thus it becomes reduced cooling during cold weather in sewer systems. Drainage pipes in houses are often uninsulated, although they can be in more or less isolated areas and could cool down the construction and nearby rooms. The purpose of this thesis is to find out if it is possible to save energy with an air admittance valve. We built an experimental facility to simulate the energy consumption. The experimental facility consists of two insulated tanks, aerated with an air admittance valve, the other with an open chimney. Then we make two different types of experiments in which we measure the temperature in the tanks. First way, we look at how quickly the water is cooled down in two insulated tanks where one tank is vented as if it were a traditional vented sewer system and the second tank is ventilated with an air admittance valve. Second way, we compare how much energy it is possible to maintain at a certain temperature in the insulated tanks. In this way, we can easily see if there are differences between the various systems. Our expected results were that youwould save energy if you used an air admittance valve. After we made our experiments we could see that our hypothesis very well matched reality. Our experiment shows that the colder it is outside, the greater energy savings you do with an air admittance valve. Energy savings can be around 13 kWh per meter sewer pipe and year, which could equate to 1-2% per year of the total heating cost of a house depending on how many meters you have. In an apartment building with 84 apartments with 45% power level of heat recovery from waste water, the energy saving will be about 10 000 kWh / year because the waste water temperature becomes one degree higher. An air admittance valve is a very cheap investment and it offers several benefits beyond saving energy. However, one must ensure that it is installed properly so it does not leak emission.

The thesis deals with wattmetric and conductance principle of faulted feeder detection in medium voltage compensated distribution networks. These principles are analysed and tested with particular emphasis on high impedance earth faults. The first part of testing utilizes data about state of the system with earth fault, which was determined by designed static model of earth fault. The testing in the second part utilizes real records of high impedance earth faults. In both parts the wattmetric and conductance protections was presented on protective relays ABB REF 615, ABB REM 543 and Protection&Consulting RYo by means of unit OMICRON CMC 256plus. As a major result of performed tests are records of detection of particular earth faults. Based on these records it could be concluded, that functionality of protections is substantially dependent on magnitude of zero sequence voltage. Furthermore the wattmetric protections are dependent on fault resistance as well.

Made available in DSpace on 2016-04-29T14:18:01Z (GMT). No. of bitstreams: 1 Solange Pacheco.pdf: 2515006 bytes, checksum: 926ec682994ae551b913dc7cbad98062 (MD5) Previous issue date: 2010-05-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study focuses on analyzing the Beneficio de Prestação Continuada da Assistencia Social (BPC), a cash transfer programme as set forth in the 1988 Brazilian Federal Constitution, the main provision of the Brazilian Social Assistance policy, aimed at elder and disable people. A highly relevant topic, as the Benefício de Prestação Continuada (BPC) grants a monthly income for elder and disable people, incapable of earning income for their own survival, or having it provided by their family. This study demonstrates the admission difficultness in the Benefício de Prestação Continuada (BPC), intending mostly on the regulating legislation s flaws put to practice on the benefit s administration. It also demonstrates the course of events of people that, after having the benefit denied, make a legal claim for it in the justice. Finally, It shows the increased right of admittance of the benefit, produced by judgmental sentences from the Federal Justice / Este estudo analisa o Benefício de Prestação Continuada da Assistência Social (BPC) que se configura como a principal provisão da Política de Assistência Social no Brasil, direcionado para idosos e pessoas com deficiência. Trata-se de um tema importante, uma vez que o Benefício de Prestação Continuada (BPC) garante uma renda mensal para pessoas idosas e com deficiência, impossibilitados de auferirem renda para a própria sobrevivência, ou de tê-la provida pela família. Demonstra-se as dificuldades de acesso ao Benefício de Prestação Continuada (BPC), tendo em vista principalmente, as imperfeições contidas na legislação regulamentadora e colocadas em prática na gestão do benefício. Mostra-se, também, o caminho percorrido pelas pessoas que, ao terem o acesso ao benefício negado, reclamam por ele na justiça. Finalmente, se evidencia a ampliação do direito de acesso ao benefício, produzida pelas sentenças de julgamento da Justiça Federal

Dans notre thèse nous nous sommes intéressés à l'étude des fluctuations de courant, de l'admittance quantique ainsi que la densité d'états pour un nano système en interaction. Notre travail se divise en deux parties. Dans la première partie, nous avons étudié les fluctuations de courant et l'admittance pour un conducteur unidimensionnel, en décrivant le système par un liquide de Tomonaga-Luttinger. Nous avons utilisé les techniques de bosonisation et de refermionisation afin d'aboutir à des résultats exacts pour tous les régimes de température, toutes les valeurs de la tension appliquée et toute la gamme des fréquences. Les résultats obtenus sont appliqués à un conducteur cohérent couplé à un quantum de résistance, et aux états de bord dans le régime de l'effet Hall quantique fractionnaire. Dans le cas d'un conducteur cohérent, le bruit non symétrisé à fréquence finie exhibe un profil différent de celui de la théorie de la diffusion, et la conductance à fréquence finie est directement liée au courant. Dans le cas du régime de l'effet Hall quantique fractionnaire, nous avons pu établir que dans certaines limites, il existe une relation entre les corrélations de courant à l'admittance quantique. En particulier, les singularités qui apparaissent dans les corrélations de courant sont celles de l'admittance. Dans la deuxième partie, nous avons étudié un fil quantique connecté à deux réservoirs qui sont représentés par deux impuretés. Le système est décrit par un liquide de Tomonaga-Luttinger. Nous avons établi et résolu l'équation de Dyson pour la fonction de Green retardée. Ce qui permet de calculer la densité d'états pour un fil quantique homogène puis inhomogène. Dans le cas d'un paramètre d'interaction homogène, l'effet des impuretés modifie le profil de la densité d'états. Dans le cas d'un paramètre d'interaction inhomogène, le calcul de la densité d'états est plus difficile et une approche numérique est indispensable.

L’oxyde de zinc ZnO, est un semiconducteur II-VI très prometteur pour les applications en opto-électronique dans le domaine UV, notamment pour la réalisation de dispositifs électroluminescents (LED). Les potentialités majeures du ZnO pour ces applications résident notamment dans sa forte liaison excitonique (60 meV), sa large bande interdite directe (3.4 eV), la disponibilité de substrats massifs de grand diamètre ainsi que la possibilité de réaliser des croissances épitaxiales de très bonne qualité en couches minces ou nano structurées (nanofils). Néanmoins, le développement de ces applications est entravé par la difficulté de doper le matériau de type p. L'impureté permettant d'obtenir une conductivité électrique associée à des porteurs de charges positifs (trous), et donc la réalisation de jonctions pn à base de ZnO, n'a pas encore été réellement identifiée. C'est pourquoi une des étapes préliminaires et nécessaires à l'obtention d'un dopage de type p fiable et efficace, réside dans la compréhension du dopage résiduel de type n, ainsi que des phénomènes de compensation et de passivation qui sont mis en jeu au sein du matériau. La maîtrise de la nature des contacts (ohmique ou Schottky) sur différentes surfaces d'échantillons de ZnO nous a permis dans ce but de mettre en œuvre à la fois des mesures de transport (résistivité et effet Hall) et des mesures capacitives (capacité-tension C(V), Deep Level Transient Spectroscopy (DLTS) et Spectroscopie d'admittance).Dans un premier temps, nous avons donc cherché à comprendre de manière approfondie les propriétés électriques du ZnO massif. Nous avons ainsi étudié le rôle des défauts profonds et peu profonds sur la conductivité des échantillons, aux travers de différents échantillons massifs obtenus par synthèse hydrothermale ou par croissance chimique en phase vapeur. Nous avons également étudié l'impact de la température de recuits post-croissance, sur les propriétés de transport des échantillons. A la lumière des résultats obtenus sur le dopage résiduel de type n des échantillons de ZnO massifs, nous avons ensuite procédé à différents essais de dopage de type p du ZnO par implantation ionique d'azote et par diffusion en ampoule scellée d’arsenic. L'impureté azote a été choisie dans le cadre d'une substitution simple de l'oxygène qui devrait permettre de créer des niveaux accepteurs dans la bande interdite du ZnO. Nous avons également étudié l'impureté arsenic, qui selon un modèle théorique peut former un complexe qui permet d'obtenir un niveau accepteur plus proche de la bande de valence que le niveau. Outres les études réalisées sur les échantillons de ZnO massif et les essais de dopage de type p, nous avons également étudié les propriétés électriques d'échantillons de ZnO monocristallins sous forme de couches minces obtenues par croissance en phase vapeur d’organométalliques, dopées intentionnellement ou non. Les corrélations entres les mesures SIMS et C(V) nous ont permis notamment de mettre en évidence une diffusion et un rôle très importante de l'aluminium sur les propriétés électriques des couches minces de ZnO épitaxiées sur substrat saphir.Dans le cadre de cette thèse nous avons réussi à clarifier les mécanismes du dopage de type n, intentionnel ou non intentionnel, dans le ZnO monocristallin. Nous avons également identifié les impuretés et les paramètres de croissance importants permettant d'obtenir un dopage résiduel de type n le plus faible possible dans les couches épitaxiées. Cette maitrise du dopage résiduel de type n est une étape préliminaire indispensable aux études de dopage de type p car elle permet de minimiser la compensation des accepteurs introduits intentionnellement. Cette approche du dopage sur des couches minces de ZnO dont le dopage résiduel de type n est très faible apparait comme une voie très prometteuse pour surmonter les problèmes d'obtention du dopage de type p. / Zinc oxide (ZnO) is a II-VI semiconductor which appears as a very promising material for UV opto-electronic applications, in particular for the production of light emitting devices (LED). For these applications, ZnO presents strong advantages as a high exciton binding energy (60 meV ), a wide direct band gap (3.4 eV), the availability of large diameter bulk substrates for homoepitaxial growth of high quality thin films or nanostructures. However, the development of these applications is hampered by the difficulty to dope ZnO p-type. The impurity leading to an electrical conductivity associated with positive charge carriers (holes), and therefore the production of ZnO pn junctions have not yet been really identified.In this thesis we have studied the physical mechanisms that govern the electrical properties of ZnO single crystal and epilayers. The control of contacts (ohmic or Schottky) on different ZnO surfaces allowed us to carry out both transport measurements (resistivity and Hall effect) and capacitance measurements (C(V), Deep Level Transient Spectroscopy (DLTS) and admittance spectroscopy).At first, we have studied the role of deep and shallow defects on the n-type conductivity of bulk ZnO samples obtained by Hydrothermal synthesis (HT) or by Chemical Vapor Transport (CVT). We also investigated the impact of post-growth annealing at high temperature under oxygen atmospheres on the transport properties of samples. Thanks to the previous results on the residual n-type doping, we have reported on several attempts to obtain p-type ZnO. We have discussed the potential of different candidates for the achievement of p-type doping and present our tentative experiments to try and demonstrate the reality, the ability and the stability of p-type doping by nitrogen implantation and arsenic diffusion. The nitrogen impurity has been chosen for oxygen substitution, which should allow the creation of acceptor levels in the ZnO band gap. We also studied arsenic as a potential p-type dopant, according to a model whereby arsenic substitutes for oxygen and, if associated with two zinc vacancies, forms a complex with a shallower ionization energy than in the case of direct oxygen substitution.In addition to the studies on bulk ZnO samples and attempts on p-type doping, we have also studied the electrical properties of thin film ZnO samples obtained by Metal Organic Vapor Phase Epitaxy, either intentionally or unintentionally doped. Correlations between SIMS and C(V) measurements allowed us to highlight especially the importance of aluminum as a residual impurity in epitaxial layers grown on sapphire substrates.In this thesis we have clarified intentional or unintentional n-type doping mechanisms in ZnO single crystal samples. We have also identified impurities and growth parameters responsible for the residual n-type doping. This understanding is a crucial and preliminary step for understanding the doping mechanisms at stake in this material and is also necessary to achieve stable p-type conductivity, which is still the main challenge for the realization of optoelectronic devices based on ZnO.

The work deals with the life and work of Přemysl Pitter, major Czech Christian humanist, representativ of the social learning, education and journalism in the 20th - 70s of the twentieth century. Introductory chapters are devoted to his childhood and youth, especially his personal reflection of the suffering experienced at the frontline on the 1st World War, which influenced his future life guidance and practical activities. Other parts of the document is characterized Pitter{\crq}s destiny and social work for others - the poor, downtrodden, necessary - in the context of the radical social and political changes in the last century. Here is a somewhat more comprehensive text on the history of the fight to save children from a concentration camps and detention camps, after World War II, ie between 1945 - 1947. The last section describes the life and operation of Přemysl Pitter after retirement emigration in 1951, when the World Council of Churches delegated the duty of pastoral and social services for refugees in the camp Valka in Nuremberg in Germany until its repeal in 1962. The final chapter describes the staying and creative activity Pitter{\crq}s exile in Switzerland in the 60s and 70s. The work includes a brief summary of the contents of archival material and archives of Přemysl Pitter and Olga Fierzová in PMJAK in Prague.