Silicon Germanium (Si1-xGex) is an alloy semiconductor that has caught considerable attention of the semiconductor industry in the past decade. Effects of strain in thin films are the reason for this. Strain leads to considerable deformation of bands providing enhanced mobility for both electrons and holes. Another important aspect of SiGe is the reduction of band gap. This makes band gap engineering feasible in all silicon technology. Yet another attractive point is the adaptability and compatibility of SiGe to silicon process technology.In CMOS circuits the p-channel MOSFET needs more than double the area of the n-channel MOSFET due to the lower mobility of holes in silicon. Hence a p-channel hetero MOSFET (HMOSFET) is chosen as the object of this dissertation.A simple general device structure that can provide considerable enhancement in performance, compared to a conventional MOSFET, is selected. A one dimensional Poisson equation is solved for this hetero junction device. Using these results an Excel spreadsheet is used as a tool to design a complete analytical program that can provide internal as well as terminal parameters of this device. The analytical program is tested by comparing the results with ISE-TCAD numerical device simulator results. The results were found to match very well. This analytical program yields results in a fraction of the time compared to numerical programs. For the device of choice variable parameters are identified. It is found that these parameters are interconnected in many ways and trade offs between them need to be applied.From the front end of the spreadsheet input parameters can be varied and parameters like potentials, hole density and terminal characteristics can be plotted very easily while simultaneously computing other parameters like threshold voltage and saturation current.The main contribution of this dissertation research is(1) Development of a very efficient and accurate analytical program to interactively design and optimize a p-channel HMOSFET(2) A detailed understanding and explanation of various design parameters, their implications, interdependency and trade offs(3) Study and explanation of certain special characteristics ofp-HMOSFET like dual threshold voltage, low off-currents, structural limitations etc.

The current development in the field of electric machinery is focusing on high-speed electric machines. This opens also other fields related to high-speed machines. One of them are magnetic bearing systems. Tradition approach of using ball bearing brings a few problems in design dealing with friction at high speeds. Together with magnetic bearings, development is their control. Faster chips opened a new way of thinking of control and helped to evolve robust control loops. The biggest advantage of magnetic bearing is non-friction run and almost no maintenance. Compare to traditional ball bearing, a magnetic bearing system needs more space and in some applications could happen that the shaft will be twice as long. This problem can be solved designing complex system with motor and integrated magnetic bearing what leads to downsizing. In this master thesis, the design of magnetic bearing for 12kw, 45000rpm is discussed. It focuses on practical design and correlations between parameter selection. The analytical approach is used to sketch the design and optimization is done afterwards. Problem with an analytical design is that it doesn't cover all parasitic phenomenae and thus numerical modelling snd optimization are demanded. Also, the critical speed analyze is included in this thesis. The results of the work will be used for manufacturing prototype as an extension to the existing high-speed machine.

Doctor of Philosophy / Department of Electrical and Computer Engineering / James E. DeVault / Prakash Krishnaswami / Most state-of-the-art systems are multidisciplinary in nature and encompass a wide range of components from domains such as electronics, mechanics, hydraulics, etc. Design considerations and design parameters of the system can come from any or a combination of these domains. The traditional optimization approach for multidisciplinary systems utilizes sequential optimization, wherein each subsystem is optimized in isolation in a predetermined order, assuming that the designs of the other subsystems remain fixed. This often leads to system designs that are suboptimal. In recent years emphasis has been placed on development of an integrated scheme for analysis and design of multidisciplinary systems. An important aspect is the software architecture required to support such a scheme. This dissertation presents MIXEDMODELS (Multidisciplinary Integrated eXtensible Engine for Driving Metamodeling, Optimization and DEsign of Large-scale Systems) - a unified analysis and design tool for multidisciplinary systems that is based on a procedural, symbolic-numeric architecture. This architecture offers great modeling flexibility at the component level, allowing any engineer to add components in his/her domain of expertise to the platform in a modular fashion. The symbolic engine in the MIXEDMODELS platform synthesizes the system governing equations as a unified set of nonlinear differential-algebraic equations (DAEs). These equations are differentiated with respect to design variables to obtain an additional set of DAEs that describe the sensitivity coefficients of the system state variables. This combined set of DAEs is solved numerically to obtain the solution for the state variables and the state sensitivity coefficients of the system. Finally, knowing the system performance functions, their design sensitivity coefficients can be calculated by using the values of the state variables and state sensitivity coefficients obtained from the DAEs. For ease in error control and software implementation, sensitivity analysis formulation described in this work uses direct differentiation approach as opposed to the adjoint variable approach. The MIXEDMODELS capabilities are demonstrated through several numerical examples and the results indicate that the MIXEDMODELS formulation and architecture is effective in terms of accuracy, modeling convenience, computational efficiency, and the ability to simulate the behavior of a general class of multidisciplinary systems.

This thesis examines the possibility of saving material by using analytical design of fire protection of glued laminated timber structures instead of the standard simplified design approach. The thesis is based on an existing store building (building class Br2 and occupancy class 2B) where Tyréns AB has determined a fire exposure specific for the store building, which is used to simulate 30 minutes of fire. The result from the simulation is then used in this thesis to evaluate the effects of said fire on a glued laminated timber structure. The analysis results in the assumption of a laterignition, since the temperature development varies from the standard fire curve used in thesimplified design approach. The thesis consists of several steps. First a glued laminated timber structure consisting of a column and beam system is designed for load bearing capacity in the ultimate and service limit state according to Eurocode. The structure is then verified for accidental actions with fire as the main action according to Eurocode using simplified design. Subsequently the same verification is carried out using the analytical design approach with the specific fire exposure. The columns are not verified since they are assumed to be exposed to direct flame impact and immediate ignition. The columns are also required to be covered with ignition retardant protection according to BBR. The result shows that no saving in material can be obtained for lower fire classes. The main reason for this is the fact that the structure design for load bearing capacity in the ultimate and service limit state is large enough to resist fire for up to 90 minutes without structural failure. For higher fire classes than R90, a potential saving in material can be achieved by using the analytical design approach. This is however deemed irrelevant, since fire classes above R30 are uncommon for these types of buildings. / I detta examensarbete undersöks möjligheten att minska materialåtgången för limträkonstruktioner genom att utföra en analytisk i stället för en förenklad brandteknisk dimensionering. Arbetet baseras på en existerande butikslokal (byggnadsklass Br2 och verksamhetsklass 2B) där Tyréns AB har tagit fram ett troligt brandförlopp i byggnaden som sedan simuleras i 30 minuter. Resultatet används i detta arbete för att utvärdera hur en limträstomme skulle påverkas vid brand i byggnaden. Analysen medför att en senare antändning för limträet kan antas, då temperaturutvecklingen ser annorlunda ut jämfört med standardbrandkurvan som används vid förenklad brandteknisk dimensionering. Arbetet består av flera steg. Först dimensioneras en limträstomme bestående av ett pelar-balksystem för butikslokalen för bärighet i brott- och bruksgränstillståndet enligt Eurokod. Sedan kontrolleras konstruktionen för ett brandlastfall med ett standardiserat brandförlopp, varpå samma kontroll utförs för balkarna enligt analytisk dimensionering med det specifika brandförloppet. Pelarna kontrolleras inte enligt det specifika brandförloppet eftersom dessa antas utsättas för direkt flampåverkan med momentan antändning. Dessutom innefattas de av ytskiktskrav enligt BBR, som kräver att de skyddas med tändskyddande beklädnad. Resultatet visar att materialåtgången inte kan minskas för lägre brandklasser. Detta beror på att dimensionerna som krävs i brott- och bruksgränstillståndet är tillräckligt stora för att konstruktionen ska klara över 90 minuters brandpåverkan utan brott. För högre brandklasser än R90 finns potential för minskning av materialåtgången genom analytisk dimensionering med ett specifikt brandförlopp. Detta anses dock inte relevant då högre brandklasser än R30 sällan förekommer i denna typ av byggnad.

S postupom času sa elektrotechnicky průmysl posouval dopředu. Přišel rozvoj v automobilovém průmyslu, leteckém průmyslu, navigácí a dalších odvětvích. S rozvojem automobilového a leteckého průmyslu se zvětšila potřeba pro motory s vyskou spolehlivostí. Tenhle fakt zapříčinil rozvoj motorů s vćero fázami. Tyto stroje mají za úkol zvýšiť spolehlivost ale zároveň zachovat/zvýšit výkon stroje.

Ziel der vorliegenden Dissertation war die Erweiterung der Kenntnisse über das nichtlinear-elastische Spannungs-Verformungsverhalten von Tragschichten ohne Bindemittel (ToB). Ein analytisches Bemessungsverfahren ist aufgrund der schwierigen Modellierbarkeit des Verformungsverhalten der einzelnen Straßenbaustoffe bisher nicht existent. Die Dissertation soll einen Beitrag zur Entwicklung eines solchen Bemessungsverfahrens leisten. Eine Literaturrecherche zum Verformungsverhalten von ToB bildet die Grundlage für die Festlegung der Vorgehensweise. Basis der weiteren Untersuchungen sind Triaxialversuche, die an der Universität Nottingham an verschiedenen Gesteinskörnungen durchgeführt wurden. Mit Hilfe der Shakedown-Theorie konnte belegt werden, dass sich ToB in unterschiedlichen Beanspruchungsbereichen nach verschiedenen Gesetzmäßigkeiten verhalten und dass Modelle zur Beschreibung des Verformungsverhaltens von ToB bereichsweise verschieden formuliert werden müssen. Somit ist es möglich, Gültigkeitsgrenzen für elastische Stoffmodelle zu ermitteln sowie Beanspruchungsgrenzen für ToB festzulegen. Mit ausgewählten Stoffmodellen erfolgten Beanspruchungsberechnungen nach der Finite-Elemente Methode (FEM). Die beste Annäherung zwischen Messwerten und Rechenergebnissen ergibt sich bei Anwendung des DRESDNER Modells. Berechnungen für Befestigungen nach den RStO 01 haben gezeigt, dass die Beanspruchungen auf den ToB bei Anwendung des DRESDNER Modells stark von denen bei Anwendung linearer Elastizität abweichen können. Durch unterschiedliche Überbauungsdicken der ToB besitzen diese einen verschieden hohen Anteil am Tragverhalten der Befestigung. Abschließend wird eine Methode zur Ermittlung von Sicherheitsniveaus vorgestellt. Bei Kenntnis der entsprechenden Schichtparameter lassen sich die Beanspruchungen jeder beliebigen Bauweise mit denen von Bauweisen nach RStO vergleichen. Als Ergebnis kann festgehalten werden, dass das Sicherheitsniveau einer bestimmten Bauweise nach RStO genauso groß ist, wie eine Befestigung mit einer dünneren Asphalttragschicht, dafür jedoch einer steiferen ToB. / The aim of this thesis was the extension of the knowledge about the resilient stress-deformation behaviour of unbound granular materials (UGM). Due to difficulties in modelling the behaviour of the single materials an analytical design method does not exist at present. Therefore this thesis makes a contribution for developing such a design method. A study of international publications about the current knowledge of the stress-deformation behaviour of UGM and repeated load triaxial tests, which have been performed at Nottingham University, were the base for all further investigations. With the shakedown concept it could be shown that materials behave in a different manner depending on the applied stress level and that material laws for describing the resilient deformation behaviour of UGM have to be formulated separately for different stress ranges. Within this thesis a method is introduced which helps to find boarders for the applicability of different material laws and limiting stress lines where below the lines stable behaviour and admissible deformations for the material are expected. Applying selected material laws finite element calculations have been performed. Comparing calculation results with measurement results it can be shown that the Dresden model offers the best approach. Calculations for pavement constructions applying the Dresden model have resulted that the vertical stresses differ very much in comparison with elastic behaviour for the UGM. It can be concluded that the thickness of the covering bounded layers have an effect to the contribution of the unbound granular layers at the complete deformation behaviour of the pavement construction. Finishing a method is introduced to determine the safety levels of pavement constructions. It seems to be possible to compare the stress-strain levels of any pavement construction with those from the german standard RStO 01. Existing functions could be modified to determine safety coefficients, i. e. ratios between admissible and existing numbers of load cycles. It can be concluded that there are the same safety levels for different pavement constructions ? a thinner asphalt layer can be compensated with a stiffer UGM.

This diploma thesis deals with the possibility of using a concentrated winding in an induction motor and the use of copper bars in a rotor cage. The first part of the thesis explains the basic theoretical knowledge of the operation and principle of the induction machine. In this theoretical part we will learn what is actually a concentrated winding and how it is placed on the stator. The second part is focused on the analytical design of the machine with classical distributed winding and with concentrated winding. The third theoretical part is an introduction to the issue of influencing the motor harmonics. The last final part of the thesis shows differences in operational properties of designed machines.

This thesis provides complete design of generator into a spinning bike. The issue of current development is solved and the analytical design of the generator is made. The software Maxwell is being used for the analysis and optimization. On the basis of the obtained results is designed a model and a design drawing of the generator. The end of the thesis deals with the issue of connecting the generator to the mains supply and price calculation of the investment return.

Characteristics of synchronous machines with permanent magnets depend among others on geometric layout of the machine section. Unlike EC motors, where rectangular arrangement of quantities is suitable, these machines require sinusoidal behaviour. Specific forming of individual machine parts is partially derived from this requirement. This thesis deals with design of such machines, including various geometrical modifications of their sections and examination of influence of those modifications. The thesis includes also analytical calculation procedure of machine parameters as well as verification of final characteristics using the finite element method. It results in a combination of various design methods. FEMM, Maxwell RMxprt and Maxwell 2D Transient Analysis programs were used for verification. Individual modifications of machine geometries are applied to machines with concentrated windings with different ratio of number of slots and poles, and differences between machines and results of individual methods are compared.

This thesis is related to axial flux permanent magnet machines. The first part is describes the basic information about this type of machines. Main part is focused on design of the machine. For the purpose of the preliminary design there is mathematical model of the basic machine. This model is followed by finite elements analysis for the further evaluations and validation of the mathematical design. The last part is evaluating the loses of the machine ant its virtual efficiency.