Solid Oxide Fuel Cells are fuel cells that operate at high temperatures usually in the range of 600oC to 1000oC and employ solid ceramics as the electrolyte. In Solid Oxide Fuel Cells oxygen ions (O2- ) are the ionic charge carriers. Solid Oxide Fuel Cells are known for their higher electrical efficiency of about 50-60% [1] compared to other types of fuel cells and are considered very suitable in stationary power generation applications. It is very important to study the effects of different parameters on the performance of Solid Oxide Fuel Cells and for this purpose the experimental or numerical simulation method can be adopted as the research method of choice. Numerical simulation involves constructing a mathematical model of the Solid Oxide Fuel Cell and use of specifically designed software programs that allows the user to manipulate the model to evaluate the system performance under various configurations and in real time. A model is only usable when it is validated with experimental results. Once it is validated, numerical simulation can give accurate, consistent and efficient results. Modeling allows testing and development of new materials, fuels, geometries, operating conditions without disrupting the existing system configuration. In addition, it is possible to measure internal variables which are experimentally difficult or impossible to measure and study the effects of different operating parameters on power generated, efficiency, current density, maximum temperatures reached, stresses caused by temperature gradients and effects of thermal expansion for electrolytes, electrodes and interconnects. iv Since Solid Oxide Fuel Cell simulation involves a large number of parameters and complicated equations, mostly Partial Differential Equations, the situation calls for a sophisticated simulation technique and hence a Finite Element Method (FEM) multiphysics approach will be employed. This can provide three-dimensional localized information inside the fuel cell. For this thesis, COMSOL Multiphysics® version 4.2a will be used for simulation purposes because it has a Batteries & Fuel Cells module, the ability to incorporate custom Partial Differential Equations and the ability to integrate with and utilize the capabilities of other tools like MATLAB ® , Pro/Engineer® , SolidWorks® . Fuel Cells can be modeled at the system or stack or cell or the electrode level. This thesis will study Solid Oxide Fuel Cell modeling at the cell level. Once the model can be validated against experimental data for the cell level, then modeling at higher levels can be accomplished in the future. Here the research focus is on Solid Oxide Fuel Cells that use hydrogen as the fuel. The study focuses on solid oxide fuel cells that use 3-layered, 4-layered and 6-layered electrolytes using pure YSZ or pure SCSZ or a combination of layers of YSZ and SCSZ. A major part of this research will be to compare SOFC performance of the different configurations of these electrolytes. The cathode and anode material used are (La0.6Sr0.4)0.95-0.99Co0.2Fe0.8O3 and Ni-YSZ respectively

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The purpose of the current exploration is creation of the mathematical model of different modifications of the underlying surface of the «forest» type. During the exploration the mathematical model of the beating signal of the altimeter was created. That’s allows to explore facet models of different types of underlying surfaces. The model was designed in the MATLAB system. As the result of the exploration the mathematical models of the underlying surfaces for different types of forests were created. During the modeling process it was designed two different variants of the model. The first variant corresponded only to the MATLAB system and based on the layers during the modeling process. The second variant is based on the 3D-Max model of the underlying surface with the following processing into the MATLAB system. The explored variants of the model allows to stress facet parameters during the furtherer exploration of the different types of the underlying surfaces. The diploma project contains four parts and includes 144 pages, 72 figures, 31 sources, 6 appendixes, 58 formulas. / Целью данной работы является создание математической модели различных модификаций подстилающей поверхности типа лес. В процессе работы была создана математическая модель сигнала биений радиовысотомера, позволяющая исследовать фацетные модели различных типов подстилающей поверхности. Модель разработана в математическом пакете MATLAB. В результате исследований созданы математические модели подстилающей поверхности для различных видов лесов. При моделировании поверхности было разработано два подхода. Первый подход использует только программный пакет MATLAB и основан на моделировании наборов фацетов в виде слоев. Второй подход основан на построении требуемой поверхности в программе трехмерной визуализации (3Ds MAX) с дальнейшей обработкой экспортированных данных с помощью разработанной модели в среде MATLAB. Исследованные подходы моделирования поверхности позволяют изучать различные типы подстилающих поверхностей, акцентируя внимание на разных параметрах фацетов. Дипломный проект содержит 144 страницы, 72 рисунка, 31 источник, 6 приложений, 58 формул, состоит из четырех глав.

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Stahlbetondeckenplatten sind material- und energieintensive Biegetragwerke, wenn sie, wie derzeit üblich, ebenflächig mit konstanter Querschnittshöhe und aus einer Betonsorte hergestellt werden. Diese Ausführung ist aus statischer und bauökologischer Sicht sehr ineffizient, da der bewehrte Beton nur an wenigen Stellen sowohl in der Haupttragrichtung als auch über die Deckenhöhe voll ausgenutzt wird. Mit einer gleichmäßigen Ausnutzung können Material und Gewicht und damit natürliche Ressourcen gespart werden. / Reinforced concrete floor slabs are materialand energy-intensive flexural load-bearing structures if, as it is currently the case, they are produced flat with a constant cross-sectional height and from one type of concrete. This design is very inefficient from a structural and building ecology point of view, as the reinforced concrete is only fully utilised at a few areas both in the main load-bearing direction and across the slab height. With an uniform utilisation, material and weight and thus natural resources can be saved.

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Sb₂S₃ and CuCl were reacted in the ionic liquid [BMIm]Cl · 4.4AlCl₃ (BMIm=1-n-butyl-3-methylimidazolium) at 200°C. Upon cooling to room temperature, orange-red colored, air-sensitive crystals of Cu(Sb₂S₃)[AlCl₄] precipitated. X-ray diffraction on a single-crystal revealed an orthorhombic crystal structure, in which cationic [Cu(Sb₂S₃)]⁺ layers are separated by tetrahedral [AlCl₄]⁻ anions. The uncharged Sb₂S₃ partial structure consists of one-dimensional strands with covalent Sb-S single bonds. The copper(I) cation is coordinated by three sulfur atoms and by one of chlorine atoms of the [AlCl₄]⁻ anion. An optical band gap of 2.14 eV was deduced from UV/Vis spectra. In very good agreement, a band gap of 2.07 eV results from DFT-based calculations involving a new implementation of the bifunctional formalism for the exchange energy. By treatment with 0.1 molar hydrochloric acid, AlCl₃ was leached from Cu(Sb₂S₃)[AlCl₄] yielding a compound with the presumed composition Cu(Sb₂S₃)Cl. Hydrolysis at higher pH resulted in Cu₂₋ₓS and Sb₄O₅Cl₂.

Software radio is a radio that is substantially defined in software and whose physical layer behavior can be significantly altered through changes to its software. As a primary goal of software radio is the ability to support existing and future wireless protocols, software radio necessitates the use of a rapidly reprogrammable baseband processing solution. However third generation wireless protocols represent a significant increase in complexity over second generation protocols. Due to the natural performance sacrifices that must be made when moving an application from an Application Specific Integrated Circuit (ASIC) to a general purpose processor or a digital signal processor, it is feared that reprogrammable processing solutions may not suffice for the emerging wireless protocols, which would significantly hinder the realization of software radio, particularly in the handheld domain where power consumption and chip area are critical. Recently, the Configurable Computing Lab at Virginia Tech developed a new breed of reprogrammable processor which they called "custom computing machine" (CCM). Representing a dramatic departure from traditional architectures used for baseband processing solutions, CCMs utilize a large number of optimized and programmable processing cores connected through a programmable mesh. Due to this architectural approach, CCMs have been promoted as supplying a level of processing power and power efficiency similar to ASICs while providing a level of reconfigurability similar to that of a DSP. Subsequently, Dr. Srikathyayani Srikanteswara proposed a new software radio architecture, known as the Layered Radio Architecture, which is intended to facilitate the inclusion of CCMs into a software radio. The primary goal of the research presented in this thesis is to demonstrate how a particular CCM, Stallion, can be used within the Layered Radio Architecture to provide sufficient processing performance, power efficiency, and reconfigurability to meet the constraints of the handheld domain through implementations of a single user adaptive receiver with adaptive complex filtering and a W-CDMA downlink rake receiver. These metrics are measured from a detailed simulation of Stallion and the Configuration Layer of the Layered Radio Architecture using advanced object oriented programming techniques that facilitate the inclusion of statistics gathering routines into normal operation. To provide perspective, these statistics are compared to the performance that could be expected from an implementation on a top-of-the-line DSP. / Master of Science