Depuis 1973, l’un des objectifs principaux de la France est la diminution de la consommation des énergies de chauffage des bâtiments du résidentiel et du tertiaire qui représentent plus de 40% de la consommation énergétique totale du pays. Le développement des isolants thermiques a été par conséquent un sujet de recherche qui a abouti à de nouveaux matériaux : les super-isolants thermiques de conductivité thermique inférieure à 25 mW.m-1.K-1. Les aérogels organiques de faible densité de Z-Phe-NH-Napht étudiés au LCPM présentent une structure fibrillaire qui leur confère des propriétés thermiques intéressantes malgré une résistance mécanique faible. Une étude fondamentale de l’organisation supramoléculaire nous a permis d’une part de démontrer l’existence de deux modes d’empilement des molécules organogélatrices : tête-à-tête (monocristaux) et tête-à-queue (gels), caractérisées par une signature infrarouge propre à des pseudo-cycles respectivement en C12 et C10/C14. D’autre part, nous avons étudié le mécanisme de formation séquentiel de ces gels et abouti à un modèle complet d’organisation de la molécule isolée à la fibre basé sur une symétrie hexagonale. En vue d’une commercialisation d’un isolant à base d’aérogel organique, nous avons tout d’abord optimisé le protocole d’obtention des aérogels pour ensuite travailler à l’amélioration des propriétés thermiques et mécaniques. Nous sommes parvenus à un nouvel isolant hydrophobe présentant une conductivité thermique de l’ordre de celles des super-isolants et de bonnes propriétés mécaniques compatibles avec les pré-requis industriels pour une application dans le bâtiment / Since 1973, France's main objective in this domain has been to reduce the consumption of energy in heating residential and industrial buildings, which represents more than 40% of the national consumption. Consequently, the development of heat insulators has been the subject of research which has resulted in new materials: super thermal insulators with a thermal conductivity of less than 25 mW.m-1.K-1. Organic aerogels with a low density of Z-Phe-NH-Napht have been studied at LCPM for the past 10 years. Despite their very weak mechanical resistance they present a fibrillar structure which gives them very interesting thermal properties. A fundamental study of the supermolecular self-assembly allowed us to demonstrate the existence of two stacking methods of gelling molecules: head-to-head (monocrystals) and head-to-tail (gels) which are characterized by a specific infrared signature to the pseudo-cycles respectively on C12 and C10/C14. In addition, we also studied the sequential formation mechanism of these gels which resulted in a full model of their molecular organization from the single molecule to the fiber and based on a hexagonal packing symmetry. In aim of commercializing an insulator made from organic aerogels, we firstly optimized the protocol for obtaining aerogels to then work on improving their thermal and mechanical properties. We created a new hydrophobic insulator which has both a thermal conductivity in the range of the super heat insulators' and good mechanical properties that are compatible with industrial prerequisites for the construction of buildings

In this thesis, quantum cluster methods are used to calculate electronic properties of correlated-electron systems. A special focus lies in the determination of the ground state properties of a 3/4 filled triangular lattice within the one-band Hubbard model. At this filling, the electronic density of states exhibits a so-called van Hove singularity and the Fermi surface becomes perfectly nested, causing an instability towards a variety of spin-density-wave (SDW) and superconducting states. While chiral d+id-wave superconductivity has been proposed as the ground state in the weak coupling limit, the situation towards strong interactions is unclear. Additionally, quantum cluster methods are used here to investigate the interplay of Coulomb interactions and symmetry-breaking mechanisms within the nematic phase of iron-pnictide superconductors. The transition from a tetragonal to an orthorhombic phase is accompanied by a significant change in electronic properties, while long-range magnetic order is not established yet. The driving force of this transition may not only be phonons but also magnetic or orbital fluctuations. The signatures of these scenarios are studied with quantum cluster methods to identify the most important effects. Here, cluster perturbation theory (CPT) and its variational extention, the variational cluster approach (VCA) are used to treat the respective systems on a level beyond mean-field theory. Short-range correlations are incorporated numerically exactly by exact diagonalization (ED). In the VCA, long-range interactions are included by variational optimization of a fictitious symmetry-breaking field based on a self-energy functional approach. Due to limitations of ED, cluster sizes are limited to a small number of degrees of freedom. For the 3/4 filled triangular lattice, the VCA is performed for different cluster symmetries. A strong symmetry dependence and finite-size effects make a comparison of the results from different clusters difficult. The ground state in the weak-coupling limit is superconducting with chiral d+id-wave symmetry, in accordance to previous renormalization group approaches. In the regime of strong interactions SDW states are preferred over superconductivity and a collinaer SDW state with nonuniform spin moments on a quadrupled unit cell has the lowest grand potential. At strong coupling, inclusion of short-range quantum fluctuations turns out to favor this collinear state over the chiral phase predicted by mean-field theory. At intermediate interactions, no robust conclusion can be drawn from the results. Symmetry-breaking mechanisms within the nematic phase of the iron-pnictides are studied using a three-band model for the iron planes on a 4-site cluster. CPT allows a local breaking of the symmetry within the cluster without imposing long-range magnetic order. This is a crucial step beyond mean-field approaches to the magnetically ordered state, where such a nematic phase cannot easily be investigated. Three mechanisms are included to break the fourfold lattice symmetry down to a twofold symmetry. The effects of anisotropic magnetic couplings are compared to an orbital ordering field and anisotropic hoppings. All three mechanisms lead to similar features in the spectral density. Since the anisotropy of the hopping parameters has to be very large to obtain similar results as observed in ARPES, a phonon-driven transition is unlikely.

Diploma project seeks for new visions in urban solutions of area south of Brno main railway station. This place could become an interesting space for new spacial creativity in connection with the project of new railway station. The work looks for alternatives to officially presented projects with orderly and straight street layouts to create pleasing and livable public space, which would become not only the tour from station to the city, but the city itself. Six meters of height difference is used to separate road and pedestrian traffic and offers an undisturbed walking movement through the elevated pedestrian streets, which are not so deep as they would be when on the ground level, so their width could be downsized to a pleasant minumum, whereas all necesary functions (like parking and supplies areas) také place below it. Geometrical concept of two shifted hexagonal grids delivers a practical large blocks on the ground level for parking and divides the area into separate projects. The walking streets` grid fractionates big portions into more subtle building block layout so comfortable for pedestrian movement. Project also deals with development phases of area to protect it from nonreversible tenous development at the beginning. The structure works as a lively city in the very beginning of the development.

This thesis aims to investigate the coefficient of friction between steel on steel contacts with the addition of solid lubricants such as h-BN, WS2, MoS2 in powder form, in dry conditions and wet conditions. More specifically, the purpose is to enhance the sliding between the piston rings and cylinder block in a modern high temperature steam engine developed by RANOTOR. The friction test was carried out as a linear sliding test with determined loads and sliding speed. Hertzian contact theory was deployed to calculate contact pressure and shear stresses to make sure the contact was elastic, alternatively plastic. It was found that WS2 and  MoS2 lowered the coefficient of friction quite heavily in dry conditions, acting as a thin protective-lubricating film. h-BN performed rather poorly, increasing the coefficient of friction. In a water slurry, none of the powders managed to decrease the COF due to the particles not interacting with the surfaces.The solid lubricants tested should be further tested as coatings since they acted like it in dry conditions. / Denna rapport syftar till att undersöka friktionskoefficienten i stålkontakter med tillsats av fasta smörjmedel som  h-BN, WS2, MoS2 i pulverform, under torra och våta förhållanden. Mer specifikt är syftet att förbättra glidningen mellan kolvringarna och insidan av cylindern i en modern högtemperatur-ångmotor utvecklad av RANOTOR. Friktionstestet genomfördes som ett linjärt glidtest med bestämda belastningar och glidhastighet. Hertzian-kontaktteorin användes för att beräkna kontakttryck och skjuvspänningar för att säkerställa att kontakten var elastisk alternativt plastisk. Det visade sig att WS2och MoS2 kraftigt sänkte friktionskoefficienten under torra förhållanden genom att agera som en tunn skyddande-smörjfilm. h-BN presterade dåligt och ökade friktionskoefficienten. I vattenblandning lyckades inget av pulverna minska friktionskoefficienten eftersom partiklarna inte interagerade med ytorna. De testade fasta smörjmedlen bör vidare testas som beläggningar eftersom de fungerade som dessa under torra förhållanden.

Объекты разработки и исследования: канал лазерной стимуляции для измерения электрофизических параметров структуры Ti/TiO2-НТ/Au и канал оптической стимуляции для исследования люминесцентных свойств нанопорошка гексагонального нитрида бора. Цель работы – разработать измерительные каналы лазерной стимуляции исследуемых образцов на основе контроля и управления параметрами излучения в различных режимах в ходе экспериментальных исследований оптически стимулированных и родственных процессов в широкозонных наноструктурированных материалах. В результате работы разработан канал лазерной стимуляции для существующего комплекса по измерению вольт-амперных характеристик на базе микрозондовой станции Cascade Microtech MPS 150, а также модернизирован канал оптической стимуляции на базе люминесцентного спектрометра Perkin Elmer LS 55 со встроенной высокотемпературной приставкой. Реализованные программно-аппаратные измерительные комплексы позволили успешно применить на практике методики исследования широкозонных наноструктур посредством оптически стимулированных процессов. Полученные в ходе работы данные, как для образцов Ti/TiO2-НТ/Au, так и для наноструктурированного порошка h-BN, отлично согласуются с результатами различных исследовательских работ из независимых научных источников. / Objects of development and research: a laser stimulation channel for measuring the electrophysical parameters of the Ti/TiO2-HT/Au structure and an optical stimulation channel for studying the luminescent properties of a hexagonal boron nitride nanopowder. The aim of the work is to develop measuring channels of laser stimulation of the studied samples based on the control and operating of radiation parameters in various modes during experimental studies of optically stimulated and related processes in wide-gap nanostructured materials. As a result of the work, a laser stimulation channel was developed for the existing complex for measuring current-voltage characteristics based on the Cascade Microtech MPS 150 microprobe station, and the optical stimulation channel was modernized on the basis of a Perkin Elmer LS 55 luminescence spectrometer with a built-in high-temperature attachment. The implemented software and hardware measuring systems made it possible to successfully apply in practice the methods of studying wide-gap nanostructures by means of optically stimulated processes. The data obtained during the work, both for the Ti / TiO2-NT / Au samples and for the nanostructured h-BN powder, are in excellent agreement with the results of various research works from independent scientific sources.

Various applications of Wireless Sensor Networks (WSNs) require accurate localization of sensor nodes. The quantity and locations of anchor nodes, which serve as reference points for distance estimates, as well as the localization process itself, affect the localization accuracy. Furthermore, because numerous communications are sent between nodes for localization, energy consumption must be considered. This work presents an energy-aware and accurate localization method. It is based on a combined anchor deployment and energy-aware localization. The proper number and distribution of anchors have been investigated to achieve full network coverage and connectivity based on an efficient and heterogeneous hexagonal deployment. Later, energy-aware localization is performed in three stages: Initialization, signal acquisition, and anchor selection. The initialization step allows the network to be adaptable to sudden changes by establishing anchor connectivity and creating the neighbors' list. Meanwhile, the Received Signal Strength Indicator (RSSI) is used for distance measurements between nodes, with the implementation of a Kalman filter to reduce signal attenuation and noise. Later, the anchor selection is done using fuzzy logic with inference parameters: RSSI, node density, and residual energy. This step ensures that only operable anchors engage in localization, while anchors with inadequate energy sources remain intact to ensure their future availability.:1 Introduction 2 Theoretical background 3 Energy-aware outdoor deployment and localization 4 Proposed anchor deployment method 5 Proposed energy-aware localization method 6 Experimental validation of the proposed localization method / Verschiedene Anwendungen von drahtlosen Sensornetzwerken (WSNs) erfordern eine genaue Lokalisierung von Sensorknoten. Die Anzahl und Standorte der Ankerknoten, die als Referenzpunkte für Entfernungsschätzungen dienen, sowie der Lokalisierungsprozess selbst beeinflussen die Lokalisierungsgenauigkeit. Da für die Lokalisierung zahlreiche Nachrichten zwischen den Knoten gesendet werden, muss außerdem der Energieverbrauch berücksichtigt werden. In dieser Arbeit wird eine energiebewusste und genaue Lokalisierungsmethode vorgestellt. Sie basiert auf einer Kombination aus effizienter Ankerknotennutzung und energiebewusster Lokalisierung. Die richtige Anzahl und Verteilung von Ankern wurde untersucht, um eine vollständige Netzabdeckung und Konnektivität auf der Grundlage einer effizienten und heterogenen hexagonalen Verteilung zu erreichen. Später wird die energiebewusste Lokalisierung in drei Stufen durchgeführt: Initialisierung, Signalerfassung und Ankerauswahl. Der Initialisierungsschritt ermöglicht es dem Netzwerk, sich an plötzliche Veränderungen anzupassen, indem es die Verbindung zu den Ankern und die Liste der Nachbarn erstellt. Zunächst wird der Received Signal Strength Indicator (RSSI) für die Entfernungsmessung zwischen den Knoten verwendet, wobei ein Kalman-Filter implementiert wird, um Signalabschwächung und Rauschen zu reduzieren. Später erfolgt die Ankerauswahl mit Hilfe von Fuzzy-Logik und Inferenzparametern: RSSI, Knotendichte und Restenergie. Dieser Schritt stellt sicher, dass nur funktionsfähige Anker an der Lokalisierung teilnehmen, während Anker mit unzureichenden Energiequellen intakt bleiben, um ihre zukünftige Verfügbarkeit zu gewährleisten.:1 Introduction 2 Theoretical background 3 Energy-aware outdoor deployment and localization 4 Proposed anchor deployment method 5 Proposed energy-aware localization method 6 Experimental validation of the proposed localization method

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<p></p><p>This doctoral dissertation takes the reader through a journey where applied shear rheology and flow-velocimetry are used to understand the mesoscopic factors that control the flow behavior of three microstructured fluids. Three individual protocols that measure relative physical and mechanical properties of the flow are developed. Each protocol aims to advance the particular transformation of novel soft materials into a commercial product converging in the demonstration of the real the chemical, physical and thermodynamical factors that could potentially drive their successful transformation. </p> <p> </p> <p>First, this dissertation introduces the use of rotational and oscillatory shear rheometry to quantify the solvent evaporation effect on the flow behavior of polymer solutions used to fabricate isoporous asymmetric membranes. Three different A-B-C triblock copolymer were evaluated: polyisoprene-<i>b</i>-polystyrene-<i>b</i>-poly(4-vinylpyridine) (ISV); polyisoprene-<i>b</i>-polystyrene-<i>b</i>-poly(<i>N</i>,<i>N</i>-dimethylacrylamide) (ISD); and polyisoprene-<i>b</i>-polystyrene-<i>b</i>-poly(<i>tert</i>-butyl methacrylate) (ISB). The resulting evaporation-induced microstructure showed a solution viscosity and film viscoelasticity strongly dependent on the chemical structure of the triblock copolymer molecules. </p> <p> </p> <p>Furthermore, basic shear rheometry, flow birefringence, and advanced flow-velocimetry are used to deconvolute the flow-microstructure relationships of concentrated surfactant solutions. Sodium laureth sulfate in water (SLE₁S) was used to replicate spherical, worm-like, and hexagonally packed micelles and lamellar structures. Interesting findings demonstrated that regular features of flow curves, such as power-law shear thinning behavior, resulted from a wide variety of experimental artifacts that appeared when measuring microstructured fluids with shear rheometry.</p> <p> </p> <p>Finally, the successful integration of shear rheometry to calculate essential parameters to be used in a cost-effective visualization technique (still in development) used to calculate the dissolution time of polymers is addressed. The use of oscillatory rheometry successfully quantify the viscoelastic response of polyvinyl alcohol (PVA) solutions and identify formulations changes such as additive addition. The flow behavior of PVA solutions was correlated to dissolution behavior proving that the developed protocol has a high potential as a first screening tool.</p><br><p></p>

In der vorliegenden Arbeit wurden Strömungen räumlich begrenzter Strahlen untersucht. Zum einen wurde die Ausströmung eines runden Strahls in ein Rohr betrachtet, der sog. begrenzte Strahl. Zum anderen wurde die Ausströmung von 7 hexagonal angeordneten runden Strahlen in ein Rohr betrachtet, das sog. hexagonale Strahlbündel. Die Motivation zur vorliegenden Arbeit ergab sich aus der Entwicklung von Durchflussmessgeräten, die als Bypassapparaturen ausgeführt sind und stromabwärts des Staudruckkörpers ein Strömungsgebiet mit begrenzten Strahlen aufweisen. Dafür wurden mit Hilfe der Ähnlichkeitstheorie die zugrundeliegenden Kennzahlen bestimmt. Besonderes Augenmerk lag auf der Charakterisierung der instationären bzw. turbulenten Strömungseigenschaften für Reynolds-Zahlen zwischen 1.000 und 20.000. Es wurden die selbstähnlichen Eigenschaften der Strömungen untersucht, wobei sich insbesondere für den begrenzten Strahl wichtige Erkenntnisse ergaben. Für das hexagonale Strahlbündel wurden mit Hilfe der numerischen Strömungssimulation die grundlegenden Eigenschaften des Strömungsfeldes untersucht. Dabei weisen die Geometriekennzahlen einen dominierenden Einfluss auf. So konnten in Abhängigkeit zum Durchmesserverhältnis und Strahlabstand drei Strömungsformen identifiziert und experimentell mittels Laser-Doppler Anemometrie nachgewiesen werden. Eine wesentliche Fragestellung bestand in der Anwendung der numerischen Strömungssimulation, des RANS-Ansatzes und des SST-Turbulenzmodells. Dazu wurde die Anpassung der Modellkoeffizienten untersucht, wobei für den begrenzten Strahl ein allgemein gültiger Satz gefunden wurde. / In the present work flows of spatially limited radiation were investigated. On the one hand, the outflow of a round jet into a pipe was considered, the so-called confined jet. On the other hand, the outflow of 7 hexagonal arranged round jets into a pipe was con-sidered, the so-called hexagonal jet array. The motivation for the present work arose from the development of flowmeters which are designed as bypass apparatures that have a jet array flow downstream of the dynamic pressure body. For this purpose the underlying similarity parameters were determined. Special attention was paid to the cha-racterization of transient and turbulent flow properties for Reynolds numbers between 1,000 and 20,000. The self-similar properties of the flows were investigated with im-portant findings in particular for the confined jet. For the hexagonal jet array the basic properties of the flow field were investigated by using computational fluid dynamics. The geometric similarity parameters have a dominant influence. Thus, depending on the di-ameter ratio and jet distance ratio, three flow patterns could be identified and experimen-tally detected by the use of laser Doppler anemometry. An important question was the application of the computational fluid dynamic method, the RANS approach and the SST turbulence model. For this purpose a generally valid set of model coefficients was found for the confined jet flow.