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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Ustálený chod a zkratové poměry v síti 110 kV E.ON při paralelním provozu uzlových oblastí R Čebín a R Sokolnice / Steady state and short-circuit conditions within E.ON 110 kV power network at parallel operation of nodal areas of Čebín substation and Sokolnice substation

Múdry, Peter January 2013 (has links)
In the distribution network 110 kV of E.ON Company there are the nodal areas of Čebin substation and Sokolnice substation which are operated separately at the present time. There is one 400/110 kV transformer for each nodal area. In case of fault on one of these transformers or on busbar in which the set transformer is working, it comes to an outage of electric supply in the set nodal area. This problem has to be solved with help of the parallel operation of nodal areas of Čebín substation and Sokolnice substation. The main and also the practical task of this work is to design the bridge connection appropriate for parallel operation of nodal areas (supply transformers 400/110 kV). With help of a computing program there were made calculations of steady state and short-circuit conditions in distribution network 110 kV for separated and parallel operation of nodal areas. Voltage conditions, load of transformers (400/110 kV and 110/vn kV) and conditions on 110 kV lines are evaluated and controlled as the result of steady state calculations. Based on short-circuit conditions there is controlled the short-circuit resistance of the substations. Finally there are compared advantages and disadvantages of separated and parallel operations of nodal areas. If necessary, technical arrangements required for introduction of parallel operation of nodal areas of Čebín substation and Sokolnice substation will be designed. The theoretical part of the work deals with calculation of steady state with help of iterative methods, namely Newton´s and Gauss-Seidel methods. There are further described the method of calculating short-circuit currents, characteristic values and time behaviours of short-circuit current.
72

Návrh úprav a konfigurace sítě 22 kV po instalaci transformace 110/22 kV ve spínací stanici Brno-sever / Proposal of design and configuration of 22 kV network after installation of 110/22 kV transformation in Brno-Sever switching substation

Mišinger, Ondřej January 2013 (has links)
The theoretical part of this thesis deals with distribution networks in terms of distribution according to different criteria, describes the main elements of electric distribution networks and their qualities. The following describes the methods of calculating the steady state of electrical networks. These methods are nowadays used as basics for computer programs. In the penultimate chapter of the theoretical part are summarized the principles for the development of present networks and construction of new electrical networks. The aim of practical part of the thesis is to assess the current condition of the network 22 kV in the city of Brno and assess the condition after installation of 110/22 kV transformation in Brno-Sever switching substation. After evaluating the results of steady state electrical network and identifying certain problems is the following aim a proposal of solving problems that emerged in the network. The result should be operational, functional and reliable electric distribution network. This thesis used to calculate the steady state electrical networks by software PAS DAISY Off-Line Bizon V4.
73

Ustálený chod a zkratové poměry v síti 110 kV E.ON při můstkovém provozu transformátorů T401 a T402 v transformovně 400/110 kV Čebín / Steady state and short-circuit conditions within E.ON 110kV power network at bridge operation of transformers T401 and T402 in 400/100kV transformer station Čebín

Klobučník, Jozef January 2014 (has links)
Master’s thesis deals with computation of steady state and short-circuit conditions in the 110 kV distribution network in the nodal area of Čebín. Computations are done during independent operation and bridge operation of transformers T401, T402 in transformation station Čebín with proposed configuration of network. Additional computations of steady state during specific operating conditions such as (T401 outage, disconnection of line 5553) were done during network operation in bridge operation of T401, T402. Voltage conditions in substations, load of 110kV lines and 400/110 kV, 110/HV kV transformers are evaluated based on the computations of steady state. Short-circuit resistance of substations is being evaluated with the aid of calculations of short-circuit conditions. There is a comparison and processed results of computations during independent operation, bridge operation, special operational states and proposed technical measures of operation in bridge operation in the end of the thesis. Theoretical part of the master’s thesis deals with the description of 110 kV distribution networks, theory of calculation of the steady state of electric system with the aid of Newton iterative method a calculation of single-phase and three-phase short-circuit current with the aid of method of symmetrical components.
74

Ustálený chod a zkratové poměry v síti 110 kV E.ON napájené z transformovny Sokolnice / Steady state and short-circuit conditions in 110kV E.ON network fed from Sokolnice transformer station

Vyčítal, Václav January 2015 (has links)
This thesis can be divided into five main parts. The first part deals with theoretical analysis of power flow calculation in power network during steady state condition. Load flow calculation is presented here as a linear and nonlinear problem. Newton iteration method is proposed for solving power flow as nonlinear problem. The second part of this thesis deals with the analysis of short-circuit calculation in accordance with valid International Standard IEC 60909. The equivalent voltage source method is adopted in case of the short-circuit calculation. For the calculation of unbalanced short-circuit currents, the symmetrical components method is also presented. The last three parts of this paper are focused on calculations of power flow and short-circuit conditions in power grid Sokolnice. So in the third part is the description of nodal area Sokolnice with its substations and the calculation of load flow and short-circuit conditions for two different power supply options. For each supply option is also considered an abnormal (fault) grid condition. (overall there are solved four different options) The fourth part of this thesis deals with the result analysis and also the results of different power supply options are compared. In the last part there are presented necessary technical improvements for fault-free operation of power grid Sokolnice based on the result of power flow and short-circuit conditions in that grid.
75

Étude structurale et fonctionnelle du canal potassium dépendant du voltage KvAP

Faure, Elise 09 1900 (has links)
Les canaux ioniques dépendants du voltage sont responsables de l'initiation et de la propagation des potentiels d'action dans les cellules excitables. De nombreuses maladies héréditaires (channelopathies) sont associées à un contrôle défectueux du voltage par ces canaux (arythmies, épilepsie, etc.). L’établissement de la relation structure-fonction exacte de ces canaux est donc crucial pour le développement de nouveaux agents thérapeutiques spécifiques. Dans ce contexte, le canal procaryote dépendant du voltage et sélectif au potassium KvAP a servi de modèle d’étude afin d’approfondir i) le processus du couplage électromécanique, ii) l’influence des lipides sur l’activité voltage-dépendante et iii) l’inactivation de type closed-state. Afin de pallier à l’absence de données structurales dynamiques du côté cytosolique ainsi que de structure cristalline dans l’état fermé, nous avons mesuré le mouvement du linker S4-S5 durant le gating par spectroscopie de fluorescence (LRET). Pour ce faire, nous avons utilisé une technique novatrice du contrôle de l’état conformationnel du canal en utilisant les lipides (phospholipides et non phospholipides) au lieu du voltage. Un modèle dans l’état fermé a ainsi été produit et a démontré qu’un mouvement latéral modeste de 4 Å du linker S4-S5 est suffisant pour mener à la fermeture du pore de conduction. Les interactions lipides - canaux jouent un rôle déterminant dans la régulation de la fonction des canaux ioniques mais ne sont pas encore bien caractérisées. Nous avons donc également étudié l’influence de différents lipides sur l’activation voltage - dépendante de KvAP et mis en évidence deux sites distincts d’interactions menant à des effets différents : au niveau du senseur de voltage, menant au déplacement de la courbe conductance-voltage, et du côté intracellulaire, influençant le degré de la pente de cette même courbe. Nous avons également démontré que l’échange de lipides autour de KvAP est extrêmement limité et affiche une dépendance à l’état conformationnel du canal, ne se produisant que dans l’état ouvert. KvAP possède une inactivation lente particulière, accessible depuis l'état ouvert. Nous avons étudié les effets de la composition lipidique et de la température sur l'entrée dans l'état inactivé et le temps de récupération. Nous avons également utilisé la spectroscopie de fluorescence (quenching) en voltage imposé afin d'élucider les bases moléculaires de l’inactivation de type closed-state. Nous avons identifié une position à la base de l’hélice S4 qui semble impliquée à la fois dans le mécanisme responsable de ce type d'inactivation et dans la récupération particulièrement lente qui est typique du canal KvAP. / Voltage-gated ion channels are responsible for the initiation and propagation of action potentials in excitable cells. Several hereditary diseases (channelopathies) are associated with a defective voltage control by these channels, leading to arrhythmias, epilepsy, etc. Hence, establishing the exact structure/function relation for ion channels is crucial for the development of new specific therapeutic agents. Here, the bacterial voltage-gated potassium channel KvAP served as a model to study i) electromechanical coupling, ii) influence of lipids on the voltage dependent activity and iii) closed-state inactivation. To overcome the lack of structural information on the cytosolic side and of crystal structure in the closed state, we determined the S4-S5 linker movement during gating using fluorescence spectroscopy (LRET). We were able to control the conformational state of the channels by using lipids (phospholipids and non phospholipids) instead of voltage clamp. Based on these experimental constraints, a model in the closed state was produced, showing that a small 4Å radial displacement of the S4-S5 linker is sufficient to close the conduction pore. Interactions between lipids and membrane proteins play an important role in the regulation of ion channels activity but are not well characterized. We studied the influence of different lipids on KvAP voltage-dependent activation and showed two distinct effects related to different interactions sites: one bound to the voltage sensor, leading to a shift of the conductance-voltage curve, and another at the intracellular side near the pore region, affecting the steepness of this curve. We also showed that the exchange of lipids is very limited around KvAP and seems to be state dependent, occuring only when the channels are kept in the open state. KvAP has a slow inactivation atypical, accessible from the open state. We studied the effects of lipid composition and temperature on entry into inactivation and recovery. We also used voltage-clamp fluorometry in bilayers to investigate closed-state inactivation molecular basis. We identified a position at the bottom of the S4 helix that seems involved in the mechanism for slow inactivation and the extremely slow recovery from inactivation typically displayed by KvAP.
76

Macromolecular Interactions in West Nile Virus RNA-TIAR Protein Complexes and of Membrane Associated Kv Channel Peptides

Zhang, Jin 01 July 2013 (has links)
Macromolecular interactions play very important roles in regulation of all levels of biological processes. Aberrant macromolecular interactions often result in diseases. By applying a combination of spectroscopy, calorimetry, computation and other techniques, the protein-protein interactions in the system of the Shaw2 Kv channel and the protein-RNA interactions in West Nile virus RNA-cellular protein TIAR complex were explored. In the former system, the results shed light on the local structures of the key channel components and their potential interaction mediated by butanol, a general anesthetic. In the later studies, the binding modes of TIAR RRM2 to oligoU RNAs and West Nile virus RNAs were investigated. These findings provided insights into the basis of the specific cellular protein–viral RNA interaction and preliminary data for the development of strategies on how to interfere with virus replication
77

Uplatňování propagandy a metod řízení a regulace regionálního tisku v Československu 1948-1956 (na příkladu direktiv KV a OV KSČ a libereckého regionu) / x

Groman, Martin January 2011 (has links)
English abstract The use of propaganda and methods of governing and regulation of the regional press in Czechoslovakia during 1948-1956 (using the example of the guidelines of KV and OV KSČ and the region around Liberec) The presented study follows the development of censorship and the methods of media and press control in Czechoslovakia from 1948 to1953, and in particular during 1956. This study focuses mainly on the methods and processes used by the Czechoslovak Communist Party to dominate the media and how it concentrated namely on the relationship between local and regional media and the centralized governance under the powerful influence of the Czechoslovak Communist Party. After February of 1948, the mass media in Czechoslovakia took on a different role than the one it had up until that time. Even so, up until 1953, there was no official censorship office and the media fell under the jurisdiction of the Party apparatus, or alternately under the Ministries of Education, Science and Arts or Information, which accordingly managed and influenced media content. However, it was still under the curatorship of the UV Czechoslovak Communist Party, as the following work will show. As will also be shown, after February of 1948 the Communist Party was unable to gain influence over society at various levels and...
78

The Mozart Flute: Old and New Transcriptions of KV. 10-15

Potts, Elizabeth (Elizabeth Ann) 05 1900 (has links)
My lecture serves as a critical examination of the Six Sonatas Op. 3, KV. 10-15 by W.A. Mozart. I will engage the variances between the first edition of Op. 3 and those by Joseph Bopp and Louis Moyse edited specifically for the flute in hopes of providing another perspective for students, performers, and pedagogues alike. This study will (1) provide background information regarding the creation of KV. 10-15, (2) include a brief analysis of each sonata, (3) compare adaptions between the first edition, according to NMA, and two modern flute transcriptions, and (4) produce two new transcriptions. My new transcriptions of Sonatas KV. 10 and 13 represent a closer interpretation to the first edition and alerts students and teachers to the differences between the editions by Joseph Bopp and Louis Moyse to that of the first and NMA editions. The goal is to stimulate performers to reappraise their approach to this particular repertoire and to encourage more authentic performances of these engaging sonatas.
79

Skola i Mariehäll / A school in Mariehäll

Urumovic, David January 2013 (has links)
Jag har ritat en skola i Mariehäll. Konceptet för skolan baserar sig på att skolans program delas upp och får rymmas i fyra volymer. Då volymerna förskjuts i relation till varandra skapas mellanrum där skolans kommunikationer sker. Det har varit viktigt att skapa välfungerande och tydliga flöden. Programmet som fördelas i de fyra huskropparna kan grovt delas upp i kategorier. En kategori innehåller utrymmen för personal, administration och lokalvård, en annan ett kulturcentrum och skolrestaurang och en tredje skolbarnens hemvist. Hemvist är en enhet som består av tre klassrum samt andra rum som krävs för att bedriva skolverksamhet. I skolan finns åtta hemvist. Kulturcentrumet är menat att användas av allmänheten utöver skoltid, på så vis integreras skolan i sin omgivning. Kulturcentrumet är placerat längs huvudstråket vid skolan, Tappvägen, för att offentliggöra verksamheten. Det har varit en utmaning att gestalta skolan så att den passar i sin kontext men att samtidigt ha en egen identitet. Exteriört präglas skolan av betong, glas och ett iögonfallande mönster av facetterad betong. Interiört har jag fullföljt en idé om en annorlunda ljusbild genom två slags fönster i fasad. Den ena typen av fönster är högt uppsatta för insläpp av ljus medan den andra typen är lägre satta gluggar som ger utblickar. Skolans kommunikationer och fördelningen av programmet har varit ett försök att skapa en icke-hierarkisk byggnad där mycket är nära till alla och där skolbarnens vistelse är trygg. / I have designed a school in Mariehäll. The concept of the school is based on that its program is divided and fitted into four volumes. These volumes are separated relative to each other and create a space in between which is used for the communications in the school. It has been important to create a well-functioning movement flow in the school. The program fitted into the four volumes can roughly be categorized. The first category contains spaces for staff, administration and cleaning, the second a culture center and the school restaurant and a third category the schoolchildren’s domicile. A domicile is a unit of three classrooms and additional rooms necessary for the domicile to function. There are eight domiciles in the school. The culture center is meant to be used by the public during off-school hours, in that way the school is integrated in its surroundings. The culture center is placed along the main road closest to the school, Tappvägen, to display the activity. It has been a challenge to design the school so that it fits in its surroundings but still has an identity of its own. The exterior of the school is mainly concrete, glass and pre-fabricated façade modules with a faceted pattern. I have followed through with a concept for the school in terms of the placement of windows. In the domiciles there are large windows placed just around eye level for an adult, these windows are supposed to let in sunlight and daylight. Another type of windows are small and placed lower, in eye level for a child standing up or a person sitting down. The smaller windows are meant to allow outlooks. The manner in which the communications and the program in the school have been distributed is the result of an attempt to design a non-hierarchical building where much is near to many and where the pupils are safe.
80

The Design, Fabrication, and Characterization of Waffle-substrate-based n-channel IGBTs in 4H-SiC

Md monzurul Alam (11184600) 27 July 2021 (has links)
<div>Power semiconductor devices play an important role in many areas, including household</div><div>appliances, electric vehicles, high speed trains, electric power stations, and renewable energy</div><div>conversion. In the modern era, silicon based devices have dominated the semiconductor</div><div>market, including power electronics, because of their low cost and high performance. The</div><div>applications of devices rated 600 V - 6.5 kV are still dominated by silicon devices, but they</div><div>are nearly reaching fundamental material limits. New wide band gap materials such as silicon</div><div>carbide (SiC) offer significant performance improvements due to superior material properties</div><div>for such applications in and beyond this voltage range. 4H-SiC is a strong candidate</div><div>among other wide band gap materials because of its high critical electric field, high thermal</div><div>conductivity, compatibility with silicon processing techniques, and the availability of high</div><div>quality conductive substrates.</div><div>Vertical DMOSFETs and insulated gate bipolar transistors (IGBT) are key devices for</div><div>high voltage applications. High blocking voltages require thick drift regions with very light</div><div>doping, leading to specific on-resistance (R<sub>ON,SP</sub> ) that increases with the square of blocking</div><div>voltage (V<sub>BR</sub>). In theory, superjunction drift regions could provide a solution because of a</div><div>linear dependence of R<sub>ON,SP</sub> on V<sub>BR</sub> when charge balance between the pillars is achieved</div><div>through extremely tight process control. In this thesis, we have concluded that superjunction</div><div>devices inevitably have at least some level of charge imbalance which leads to a quadratic</div><div>relationship between V<sub>BR</sub> and R<sub>ON,SP</sub> . We then proposed an optimization methodology to</div><div>achieve improved performance in the presence of this inevitable imbalance.</div><div>On the other hand, an IGBT combines the benefits of a conductivity modulated drift</div><div>region for significantly reduced specific on-resistance with the voltage controlled input of a</div><div>MOSFET. Silicon carbide n-channel IGBTs would have lower conduction losses than equivalent</div><div>DMOSFETs beyond 6.5 kV, but traditionally have not been feasible below 15 kV. This</div><div>is due to the fact that the n+ substrate must be removed to access the p+ collector of the</div><div>IGBT, and devices below 15 kV have drift layers too thin to be mechanically self-supporting.</div><div>In this thesis, we have demonstrated the world’s first functional 10 kV class n-IGBT with</div><div>a waffle substrate through simulation, process development, fabrication and characterization.</div><div><div>The waffle substrate would provide the required mechanical support for this class of devices.</div><div>The fabricated IGBT has exhibited a differential R<sub>ON,SP</sub> of 160 mohm</div><div>.cm<sup>2</sup>, less than half of</div><div>what would be expected without conductivity modulation. An extensive fabrication process</div><div>development for integrating a waffle substrate into an active IGBT structure is described</div><div>in this thesis. This process enables an entirely new class of moderate voltage SiC IGBTs,</div><div>opening up new applications for SiC power devices.</div></div>

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