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The increased moisture of the building materials causes the change of its mechanical and physical characteristic. In particular the high amount of loose water in construction shorten the lifetime of the building, is harmful to human beings due to biotic factors and increase the economic expenses of usage of the building. Apart from the costs of rehabilitation the loose water deteriorates the thermal insulative ability (thermal conductivity coefficient ) of perimeter masonry as well. The moisture gets into masonry not only through its deffects but also due to many different reasons. In order to improve the utility value of the buildings we have to deal with the rehabilitation of damp masonry with view to all possible causes. Only the properly working damp proofing ensures the protection against the water leaking from the subfoundation of the building. One of the direct techniques which have undergone rapid progress in last few years is the injection procedure. With use of experimental methods in my dissertation I deal with evaluation of two injection compounds used in Czech Republic and with its impact on the characteristics of the mortar. With the modern hollow bricks (system THERM) it is possible to create horizontal infusion into the lateral mortar grooves in future.

Tato diplomová práce otevírá otázku možnosti zlepšení vlastností kompresoru za pomoci numerické simulace proudění. Hlavním cílem je zvýšení operačního rozsahu na jednom stupni axiálního kompresoru s využitím zařízení pro pasivní kontrolu proudu umístěných ve skříni kompresoru. Prvně bylo prověřeno chování víru ve štěrbině mezi lopatkou a skříní následně celkové charakteristiky původního rotoru. Při snižování hmotnostního průtoku simulace odhalila zvýšený vliv koncového výru na hlavní proud. Navíc byl největší koncový vír v režimu blízkém odtrhávání proudění. Z tohoto důvodu byly pro kontrolu koncového víru navrženy čtyři verze drážkování implementováním sinusové úpravy geometrie. Tři ze čtyř testovaných verzí ukázaly možnost výrazného zvýšení rozsahu stabilního proudění. Nicméně prodlužení operačního rozsahu mělo za následek snížení celkové účinnosti. Na konec této práce jsou navrženy doporučení pro další výzkum.

As the need for highly efficient transmission systems increase, it is imperative to have lower fuel consumption levels. Hence, it becomes crucial to investigate and understand reasons behind various losses occurring within the system. Clutches and gears contribute to the major losses within a transmission system. In this thesis project, the drag losses in disengaged wet clutch is studied and efforts have been made to come up with solutions to reduce these losses. Computational Fluid Dynamics (CFD) is used as tool to understand the oil flow in the clutch system. The thesis tasks focused on: - Better understanding of flow physics and oil inlet to the clutch pack - Design and analysis of groove patterns to reduce drag loss - Understand the effect of rotation of clutch discs on groove functionality - Development of a multiphase CFD model with realistic boundary conditions for clutch analysis Initially, the entire clutch pack is modelled to study the oil flow and estimate the amount of oil that is being pumped into the individual gaps between the steel plates and friction discs. To analyze different groove patterns, the clutch model was simplified and only the gap having higher mass flow rate has been considered for simulation. A background study has been done to understand the effect of different clutch parameters on drag losses. Based on the understanding from the literature study, two groove patterns- inclined grooves and waffle grooves have been designed and analyzed in this thesis work. A simplified model with periodic boundary condition and a complete single disc model have been set up and simulated to compare the two groove patterns. To reduce the computational time, at first, a periodic model is set up for groove study. Due to numerical instability observed in the results obtained by using model with periodic boundary condition, the complete single disc model is used for further groove study and comparison. To understand the effect of rotation on grooves, two models have been set up, one with stationary grooves and the other with rotating grooves. While performing the simulations, the temperature and the oil properties have been considered constant. As there were no test results available, the CFD results could not be validated. Convective heat transfer coefficient is estimated to compare the cooling effect of different grooves. An optimal groove pattern would be the one that dissipates oil faster and efficiently out of the clutch pack, and at the same time has better cooling effect. From the results obtained, the inclined grooves were more efficient than waffle grooves in dissipating oil and reducing drag losses. On the other hand, waffle grooves have higher convective heat transfer coefficient when compared to inclined grooves and are better for cooling. / På grund av de ökande kraven på transmissionssystemen är det av stort intresse att även öka deras verkningsgrad för att uppnå lägre bränsleförbrukning. Det blir då viktigt att förstå orsakerna bakom de förluster som uppstår inom systemet. Kopplingar och växlar bidrar till de största förlusterna inom ett transmissionssystem. I denna avhandling studeras strömningsförlusterna i en frånkopplad våtkoppling och försök görs att hitta lösningar för att minska dessa förluster. Computational Fluid Dynamics (numeriska flödesberäkningar) används som ett verktyg för att förstå oljeflödet i kopplingssystemet. Avhandlingens fokus ligger på följande områden: - Förbättra förståelsen för flödesfysik och oljetillförsel till kopplingspaketet - Design och analys av spårmönster för att minska strömningsförluster - Förstå effekten av kopplingsskivornas rotation på spårens funktion - Utveckling av en flerfas CFD-modell med realistiska randvillkor för kopplingsanalys Först modelleras hela kopplingspaketet för att studera oljeflödet och beräkna mängden olja som pumpas in i mellanrummen mellan stålplattorna och friktionsskivorna. För att analysera olika spårmönster förenklades kopplingsmodellen och endast det mellanrum med högst massflödeshastighet har beaktats för simulering. En bakgrundsstudie har gjorts för att förstå effekten av olika parametrar på strömningsförlusterna. Baserat på förståelsen från litteraturstudien har två spårmönster – lutande spår och våffelspår, utformats och analyserats i detta arbete. En nedskalad periodisk modell och en komplett enkelskivsmodell har skapats och simulerats för att jämföra de två spårmönstren. För att minska beräkningstiderna för simuleringarna, användes en periodisk modell för spårgeometristudien. På grund av numerisk instabilitet som observerades i resultaten från den periodiska modellen används den kompletta enkla skivmodellen för ytterligare analys och jämförelse. För att förstå rotationseffekten på spåren har två modeller upprättats, en med stationära spår och en med roterande spår. Under simuleringen har temperaturen och oljeegenskaperna antagits vara konstanta. Eftersom det inte fanns några testresultat tillgängliga kunde CFD-resultaten inte verifieras. Den konvektiva värmeöverföringskoefficienten uppskattades för att kunna jämföra hur kylförmågan påverkas av olika spårgeometrier.  Ett optimalt spårmönster bör utformas sådant att det minskar förlusterna genom att skingra oljan snabbt och effektivt i hela kopplingspaketet, och samtidigt ger en bättre kylningseffekt. Enligt de erhållna resultaten var de lutande spåren effektivare än våffelspår i att skingra olja och reducera strömningsförluster. Å andra sidan ger spår med våffelmönster en högre konvektiv värmeöverföringskoefficient jämfört med lutande spår och därmed förbättrad kylförmåga.

Nous avons étudié in situ et en temps réel la structure de grains du silicium multi-cristallin issue de la solidification dirigée en utilisant l’imagerie X synchrotron. La radiographie X permet de suivre l’évolution de l’interface solide/liquide et de caractériser sa dynamique et sa morphologie. La topographie X nous donne des informations sur la structure de grains formée, les contraintes et les défauts issus de la solidification. Nous avons montré l’importance la préparation de l’état initial de la solidification en particulier pour les expériences de reprise sur germe. L’analyse de la morphologie de l’interface solide/liquide nous a permis de caractériser la surfusion cinétique du front de solidification, de comprendre l’évolution des sillons de joints de grains et d’analyser les mécanismes de compétition de grains ainsi que de révéler l’impact des impuretés sur la structure de grains formée à l’issue de la solidification. Le phénomène de maclage a aussi été observé dans nos expériences et nous avons démontré que les macles dans le silicium multi-cristallin peuvent être des macles de croissance. Deux types de macles ont été identifiés et le phénomène de compétition de grains en présence de macles étudié. / We studied in situ and real-time the grain structure of multi-crystalline silicon from directional solidification using synchrotron X-ray imaging techniques. X-ray Radiography gives information on the evolution, dynamics and morphology of the solid/liquid interface. X- ray Topography gives more information on the grain structure, strains and defects that occur during solidification step. We showed the importance of the preparation of the initial stage of solidification in particular in the experiments where solidification is initiated from seed. The analysis of the solid/liquid interface morphology allowed us to characterize the kinetic undercooling of the solidification front, to understand the evolution of the grains boundary grooves and to analyze the mechanisms of grain competition and also to reveal the impurities impact on the grain structure formed at the end of the solidification. We also observed twinning phenomenon in our experiments and we demonstrated that twins in multi-crystalline silicon can be growth twins. Two kinds of silicon twins have been identified and the grain competition phenomenon with twins studied.

Game theory and mechanism design have emerged as an important tool to model, analyze,and solve decentralized design problems involving multiple agents that interact strategically in a rational and intelligent way. Some examples of these design problems include: auctions and markets in electronic commerce; network economics; dynamic pricing; routing protocols in wireless networks; resource allocation in computational grids; algorithms for selfish agents;etc. The motivation for this doctoral work springs from the high level of current interest indesigning innovative mechanisms for solving emerging game theoretic problems in the area of electronic commerce. In this thesis, we focus on three such problems and advance the current art in mechanism design while developing new, innovative mechanisms to solve the problems. The first problem we explore is the highly strategic problem of forming a high value E-business supply chain by choosing the best mix of supply chain partners. In our research, we formulate the supply chain formation problem as a mechanism design problem in a generic wayand show that the well known VCG (Vickrey-Clarke-Groves) mechanisms provide an apt frame-work for solving this problem. We provide a compelling example of a three stage automotive distribution network to illustrate the power and e±cacy of the proposed methodology. The second problem we model and solve is that of designing a revenue maximizing sponsored search auction. This is a problem that is faced by every Internet search engine, such as Google,MSN, and Yahoo!, whenever it receives a search query. In our research, we take a comprehensivelook at existing auction mechanisms for this problem. Our work leads to an innovative new auction mechanism, which we call OPT (optimal mechanism), that exhibits a superior level ofperformance. The proposed mechanism extends, in a non-trivial way, the well known Myersonoptimal auction to the specific setting of sponsored search auctions. The proposed mechanism maximizes the revenue to the search engine and also satisfies two crucial properties, Bayesian incentive compatibility and interim individual rationality. The third contribution is in respect of Stackelberg problems, which are game theoretic problems that involve hierarchical and sequential decision making. By focusing attention on an important subclass of these problems, namely the Single-Leader-Rest-Followers (SLRF) problems, we extend all relevant aspects of classical mechanism design theory to the case of SLRF problems. We derive many important results in respect of procurement auctions with reserve prices using the developed theory. The research carried out as part of this doctoral work, we believe, advances the current art in mechanism design while developing innovative mechanisms to solve those problems.

This Master’s thesis investigates the flow in sealing gaps of impeller within pumps and turbines. Sealing gaps are installed to improve the volumetric efficiency in this type of fluid machinery. Despite present extensive research this subject has not been entirely documented and the thesis’ aim is to improve our knowledge in this matter. At the beginning, the practical experiment is used in order to establish appropriate numerical description of flow in seals and to calibrate software FLUENT. In chapter five, the thesis analyses the influence of seal design on volumetric efficiency of pumps and turbines and defines its optimal construction to improve the efficiency. The thesis then examines the effect of rotor eccentricity on flow properties, flow rate and pressure distribution within the sealing gap. In the last section, through chapters six to eight, the flow results provided by numerical solution in FLUENT and selected analytical equations, or their modified forms, are being discussed. The degree of correspondence between the results is also studied.

Denna uppsats undersöker Storsudret, Gotlands sydligaste udde, i ett övergripande perspektiv av landskapet och dess geografiska egenskaper, samt Sundre socken för en lokal analys av fornlämningar och människorna i området. Sydvästligast ligger Hoburgen, en klint eller klippa som har satt spår i den gotländska kulturen på flera olika sätt. Baserat på studerandet av kartor, analys av ett osteologiskt material samt etymologiska kopplingar till Hoburgen målar detta arbete en nyanserad bild av platsen och människorna däri. Genom att studera dessa aspekter kommer vi närmare att förstå människornas relation till platsen genom tiderna och varför man valt att återkomma och återbruka forna tiders gravplatser. / This thesis examines Storsudret, Gotland’s southernmost peninsula, through an overview perspective of the landscape and its geographical features, as well as Sundre parish for a local analysis of ancient monuments and the people in the area. The south-westernmost point is Hoburgen, a cliff that has left an imprint in the Gotlandic culture in various ways. Through the study of maps, analysis of osteological remains, and etymological connections to Hoburgen, this thesis demonstrates a nuanced picture of the place and the people within. By studying these aspects, we come closer to understand people’s relationship to the landscape throughout the ages and why they chose to return to it and reuse ancient burial sites. / Gotland under det 3:e årtusendet f.Kr.

The thesis theme is the design of 3 MW high-speed permanent magnet synchronous motor. The work is divided into several parts, and contains the information given on the topic. The first part lists trends and new technologies of high-speed electric machines, and the issues and construction of high-speed synchronous machines are also listed here. In the second part, the machine is analytically designed from the specified values, which is then modelled in the RMxprt program. In the penultimate part, the engine is simulated by programs that are included in the ANSYS Electronics Desktop package, they are RMxprt and Maxwell. The modified engine model in RMxprt is simulated using defined formulas and then converted to Maxwell 2D, where the engine is simulated using the finite element method. In the last part, the results from the analytical calculation are compared with other high-speed machines. In addition, the results of simulations from RMxprt and Maxwell were compared in the last part.