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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.
491

Vliv mnohonásobného zatěžování na vybrané parametry lehkého betonu / Influence of multiple cyclic loading on the selected parameters of lightweight concrete

Alexa, Martin January 2018 (has links)
The diploma thesis deals with the observation of the values of selected parameters (especially the static modulus of elasticity) of light-weight concrete in compression before and after multiple cyclic loading. The deformation of test specimens during multiple cyclic loading were measured with resistive strain gauges. Test specimens (cylinders with a diameter of 150 mm and height of a 300 mm) were cyclically loaded and up to 4 500 loading cycles were performed. The aim of this thesis is assessment changes in the values of static modulus of elasticity depending on the number of loading cycles.
492

Daňové dopady přeměn obchodních společností / Tax Implications of Company Transformations

Bělehrádek, Michael January 2021 (has links)
The diploma thesis is focused on accounting, tax and legal aspects of company transformations. The paper contains the definition of the theoretical bases and a detailed analysis of the four already implemented transformations of mergers by acquisition and division by splitting. Furthermore, the methods of transferring the assets of a real company in the form of a division by splitting through merger and also the transfer of a commercial establishment are compared. In the end, variant specific procedures for the transfer of the property in question are proposed.
493

Computational and Experimental Studies of the Photoluminescence, Reactivity and Structural Properties of d10 and d8 Metal Complexes

Otten, Brooke Michelle 05 1900 (has links)
Computational chemistry has gained interest as a characterization tool to predict photoluminescence, reactivity and structural properties of organic and transition metal complexes. With the rise of methods including relativity, these studies have been expanded to the accurate modeling of luminescence spectra of complexes with considerable spin-orbit splitting due to heavy metal centers as well as the reaction pathways for these complexes to produce natural products such as hydrogen gas. These advances have led to the synthesis and utility of more effective catalysis as well as the development of more effective organic light emitting diodes (OLEDs) through the incorporation of organometallic complexes as emitters instead of typical organic emitters. In terms of significant scientific advancement presented in this work is in relation to the discovery of significant spin-orbit splitting in a gold(I) alkylphosphine complex, where the splitting results in the states that emit in different colors of the visible region of the electromagnetic spectrum. This work also reveals the discovery both computationally and experimentally, of a genuine polar-covalent bond between two-closed shell metals. This work highlights a complex with an incredibly short gold(I) – copper(I) intermetallic distance leading to a vibrational frequency and dissociation energy that is on par with those of other systems with single-bonded metal centers. Lastly, this work outlines a strategy for the production of hydrogen gas through the use of trinuclear cyclic coinage metal complexes as catalysis to split hydrohalic acids.
494

Fotokatalytický rozklad vody oxidovými polovodiči modifikovanými grafenem/grafenoxidem / Photocatalytic water splitting by oxide semiconductors modified with graphen/graphenoxide

Marek, Jiří January 2015 (has links)
This master thesis deals with the topic of alternative production of hydrogen as the energy carrier of the future. The primary focus is on the production of hydrogen based on photocatalytical water splitting in the presence of semiconductor materials (especially modified and unmodified TiO2). The aim of the thesis is a synthesis of nanostructured oxide, graphene/graphene oxide particles and its composites, and a study of its structures and photocatalytical properties regarding photolysis of water. Products of the syntheses are described from the point of view of phase composition, surface area and photocatalytical activity. The main output of the thesis is a discussion of the influence of alkaline complex forming reagents on the hydrothermal low-temperature synthesis of biphasic TiO2, and a study of the influence of graphene/graphene oxide modification on photocatalytical activity of biphasic TiO2.
495

Analýza porušování kvazikřehkých materiálů za použití numerického modelování a akustické/elektromagnetické emise / Analysis of fracture of quasibrittle materials using numerical modelling and acoustic/electromagnetic emission

Vodák, Ondřej January 2013 (has links)
This master thesis gives overview of non-destructive tests of concrete and provides detailed information concerning the acoustic and electromagnetic emission during monitoring of concrete failure. Conducted loading tests of plain concrete specimens are described in the thesis together with the performed numerical simulations of these tests in the software ATENA. The simulation results of concrete failure are analysed in detail and compared with the experimental results recording failure processes with the help of acoustic and electromagnetic emission. The majority of simulation results in software ATENA 3D show good agreement with the recorded data.
496

Konstrukce mobilního horizontálního štípacího stroje na dřevo / Design of mobile horizontal wood-splitting machine

Dressler, Jan January 2010 (has links)
This thesis shows making of documentation for production powerfull wood-splitting machine for hardest forestal work. There are researched and soluted all phases of pre-production machine's lifecycle, also means analysis of conception, potentional risks and failures analysis and also definition of required properties. Based on those properties and results of analyses is possible to setting up condition which should be satisfied. At following part are descripted and shown features of machine-design . Main feature (component) of machine is its frame, also there are strenght analysis of frame. Machine movement features are mainly hydraulics pistons which are powered by asynchronous engine, whith alternative possibility movement by wheel tractor power-take off shaft or hydraulics output. There are performed all important properties. Working safety questions and high endurability of machine shold be also performed. At the end of work is realised conception and design study of forestal production system for wood processing with one universal source of energy – wheeled tractor.
497

Le cadre juridique des investissements internationaux en République démocratique du Congo / The legal framework for international investment in the Democratic Republic of the Congo

Iririra Nganga, Dan 29 June 2019 (has links)
L’investissement étranger est considéré aujourd’hui comme un facteur clé voire une valeur ajoutée à même de faciliter le développement de l’État d’accueil. Ainsi, l'État congolais mise sur l’amélioration de son arsenal juridique interne dont l’objectif consiste à attirer de nombreux investisseurs et investissements étrangers sur son territoire. Pour ce faire, des réformes tendant à l’amélioration de principaux textes juridiques applicables directement ou indirectement en matière d’admission et de sécurisation des investissements étrangers afin de se conformer aux standards internationaux deviennent une obsession pour cet État, dont la finalité demeure : la valorisation de ses ressources naturelles notamment le cobalt, le germanium et la colombo-tantalite etc. très souvent inexploitées et utile à même de servir à la production des batteries pour les voitures électriques. Il serait donc nécessaire désormais que le contrôle de l’État souverain sur ses ressources naturelles considérées comme des minerais stratégiques soit davantage renforcé et que le contentieux en matière d’investissement soit confié à des entités qui prennent en compte l’intérêt général au détriment des arbitrages sous l’égide des arbitres privés, défendant les intérêts privés. Ainsi, la création d’un Centre international africain de règlement des différends pourrait être profitable notamment en permettant aux experts africains - tant arbitres qu’avocats - d’être plus présents dans le cadre des procédures impliquant leurs États d’origine / Foreign investment is now considered a key factor or even an added value that can facilitate the development of the host country. Thus, the Congolese State is focusing on improving its domestic legal arsenal, the objective of which is to attract many foreign investors and investments to its territory. To this end, reforms aimed at improving the main legal texts directly or indirectly applicable to the admission and security of foreign investments in order to comply with international standards are becoming an obsession for this State, the purpose of which remains: the development of its natural resources, in particular cobalt, germanium and colombo-tantalite etc., which are very often unexploited and useful for the production of batteries for electric cars. It would therefore now be necessary for the sovereign State to strengthen its control over its natural resources considered as strategic minerals and for investment litigation to be entrusted to entities that take into account the general interest to the detriment of arbitrations under the aegis of private arbitrators, defending private interests. Thus, the creation of an African International Dispute Resolution Centre could be beneficial, in particular by allowing African experts - both arbitrators and lawyers - to be more present in proceedings involving their States of origin
498

Strain-tuning of single semiconductor quantum dots

Plumhof, Johannes David 03 February 2012 (has links)
Polarization entangled photon pairs on demand are considered to be an important building block of quantum communication technology. It has been demonstrated that semiconductor quantum dots (QDs), which exhibit a certain spatial symmetry, can be used as a triggered, on-chip source of polarization entangled photon pairs. Due to limitations of the growth, the as-grown QDs usually do not exhibit the required symmetry, making the availability of post-growth tuning techniques essential. In this work first the QD-morphology of hundreds of QDs is correlated with the optical emission of neutral excitons confined in GaAs/AlGaAs QDs. It is presented how elastic anisotropic stress can be used to partially restore the symmetry of self-assembled GaAs/AlGaAs and InGaAs/GaAs QDs, making them as candidate sources of entangled photon pairs. As a consequence of the tuning of the QD-anisotropy we observe a rotation of the polarization of the emitted light. The joint modification of polarization orientation and QD anisotropy can be described by an anticrossing of the so-called bright excitonic states. Furthermore, it is demonstrated that anisotropic stress can be used to tune the purity of the hole states of the QDs by modifying the degree of heavy and light hole mixing. This ability might be interesting for applications using the hole spin as a so-called quantum bit.
499

Charged particle distributions and robustness of the neural network pixel clustering in ATLAS

Sidebo, Edvin January 2016 (has links)
This thesis contains a study of the robustness of the artificial neural network used in the ATLAS track reconstruction algorithm as a tool to recover tracks in dense environments. Different variations, motivated by potential discrepancies between data and simulation, are performed to the neural network’s input while monitoring the corresponding change in the output. Within reasonable variation magnitudes, the neural networks prove to be robust to most variations. In addition, a measurement of charged particle distributions is summarised. This is one of the first such measurements carried out for proton-proton colli- sions at √s = 13 TeV, limited to a phase space defined by transverse momentum pT &gt; 100 MeV and absolute pseudorapidity |η| &lt; 2.5. Tracks are corrected for de- tector inefficiencies and unfolded to particle-level. The result is compared to the prediction of different models. Overall, the EPOS and Pythia 8 A2 models show the best agreement with the data. / Spår från elektriskt laddade partiklar rekonstrueras i ATLAS genom att kombinera mätningar från de innersta subdetektorerna. I de extrema miljöer som skapas i proton-proton-kollisionerna i Large Hadron Collider vid CERN är det av yttersta vikt att algoritmen för att rekonstruera spår är högpresterande. Uppgiften är särskilt svår i partikelrika miljöer där flera partiklar färdas nära varandra, åtskilda av avstånd jämförbara med storleken på detektorns utläsningselement. Ett artificiellt neuralt nätverk används i algoritmen för att klassificera mätdata från pixeldetektorn, belägen närmast interaktionspunkten, för att lyckas identifiera spår i partikelrika miljöer som annars hade gått förlorade. I denna avhandling utreds det neurala nätverkets stabilitet. Dess känslighet studeras genom att manuellt manipulera dess indata och därefter utvärdera dess resultat. Nätverket tränas med simulerad data. Variationerna i indata är utformade för att undersöka skillnader mellan data och simulering, orsakade av osäkerheter i simuleringsmodellen eller osäkerheter i pixeldetektorns kalibrering. Av de undersökta variationerna har en osäkerhet i skalan eller utläsningströskeln för pixeldetektorns kalibrering den största effekten på nätverkets resultat. Andra variationer har en betydligt mindre påverkan. Avhandlingen presenterar också en studie av distributioner av elektriskt laddade partiklar producerade i proton-proton-kollisioner. Det är en av de första studierna av partikeldistributioner för Large Hadron Colliders andra körning med mass-centrum-energi √s = 13 TeV. Mätningen är begränsad till fasrymden definierad av en transversell rörelsemängd pT &gt; 100 MeV, och absolut rapiditet |η| &lt; 2.5. Spår av partiklar rekonstrueras och korrigeras för detektorns ineffektiviteter för att presenteras på partikelnivå. Dessa jämförs sedan med förutsägelser från olika modeller. Modellerna EPOS och Pythia 8 A2 är generellt de som bäst överensstämmer med data. Författaren har undersökt partiklar som migrerar in och ut ur fasrymden. Andelen spår associerade till partiklar som migrerat utifrån uppskattas med simulerad data, till som mest 10% nära fasrymdens gränser. Osäkerheten på denna andel uppskattas till att vara som mest 4.5%, huvudsakligen orsakad av osäkerheten på mängden material i de innersta subdetektorerna. / <p>QC 20160817</p>
500

Network-Calculus-based Performance Analysis for Wireless Sensor Networks

She, Huimin January 2009 (has links)
Recently, wireless sensor network (WSN) has become a promising technologywith a wide range of applications such as supply chain monitoringand environment surveillance. It is typically composed of multiple tiny devicesequipped with limited sensing, computing and wireless communicationcapabilities. Design of such networks presents several technique challengeswhile dealing with various requirements and diverse constraints. Performanceanalysis techniques are required to provide insight on design parametersand system behaviors. Based on network calculus, we present a deterministic analysis methodfor evaluating the worst-case delay and buffer cost of sensor networks. Tothis end, three general traffic flow operators are proposed and their delayand buffer bounds are derived. These operators can be used in combinationto model any complex traffic flowing scenarios. Furthermore, the methodintegrates a variable duty cycle to allow the sensor nodes to operate at lowrates thus saving power. In an attempt to balance traffic load and improveresource utilization and performance, traffic splitting mechanisms areintroduced for mesh sensor networks. Based on network calculus, the delayand buffer bounds are derived in non-splitting and splitting scenarios.In addition, analysis of traffic splitting mechanisms are extended to sensornetworks with general topologies. To provide reliable data delivery in sensornetworks, retransmission has been adopted as one of the most popularschemes. We propose an analytical method to evaluate the maximum datatransmission delay and energy consumption of two types of retransmissionschemes: hop-by-hop retransmission and end-to-end retransmission. We perform a case study of using sensor networks for a fresh food trackingsystem. Several experiments are carried out in the Omnet++ simulationenvironment. In order to validate the tightness of the two bounds obtainedby the analysis method, the simulation results and analytical results arecompared in the chain and mesh scenarios with various input traffic loads.From the results, we show that the analytic bounds are correct and tight.Therefore, network calculus is useful and accurate for performance analysisof wireless sensor network. / Ipack VINN Excellence Center

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