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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.
401

Náhrobní mříž v českých zemích v období raného novověku. Mříž a hrobový prostor 1550-1740 / Sepulchral Ironwork in Early Modern Bohemia. Ironwork and Sepulchral Environment between 1550-1740

Gandalovičová, Šárka January 2015 (has links)
The text deals with various types of ironwork from ca 1550-1740, which we can encounter in sepulchral spaces in Bohemia. The text includes notable examples of individual types of ironwork related to sepulchral monuments in Bohemia and even Central Europe, especially when the works were inspired by Bohemian examples. The main research subject matter of the dissertation is a typological group of ironwork that defined the space around a tombstone or mausoleum freely situated in a sacred environment, e.g. the most important cited work - the ironwork surrounding the Royal Mausoleum in Prague, or the ironwork surrounding the Cenotaph of Maxmilian I located in the Court Church of Innsbruck. Other types of ironwork related to sepulchral monuments are mentioned complementarily, such as ironwork closing off interior chapels, freely standing ironwork, and ironwork protecting sepulchral niches. Powered by TCPDF (www.tcpdf.org)
402

CHAIN-LENGTH PROPERTIES OF CONJUGATED SYSTEMS: STRUCTURE, CONFORMATION, AND REDOX CHEMISTRY

Saadia T Chaudhry (8407140) 22 April 2021 (has links)
The development of solution-processable semiconducting polymers has brought mankind’s long-sought dream of plastic electronics to fruition. Their potential in the manufacturing of lightweight, flexible yet robust, and biocompatible electronics has spurred their use in organic transistors, photovoltaics, electrochromic devices, batteries, and sensors for wearable electronics. Yet, despite the successful engineering of semiconducting polymers, we do not fully understand their molecular behavior and how it influences their doping (oxidation/reduction) properties. This is especially true for donor-acceptor (D-A) p-systems which have proven to be very efficient at tuning the electronic properties of organic semiconductors. Historically, chain-length dependent studies have been essential in uncovering the relationship between the molecular structure and polymer properties. Discussed here is the systematic investigation of a complete D-A molecular series composed of monodispersed and well-defined conjugated molecules ranging from oligomer (n=3-21) to polymer scale lengths. Structure-property relationships are established between the molecular structure, chain conformation, and redox-active opto-electronic properties for the molecular series in solution. This research reveals a rod-to-coil transition at the 15 unit chain length, or 4500 Da, in solution. The redox-active optical and electronic properties are investigated as a function of increasing chain-length, giving insight into the nature of charge carriers in a D-A conjugated system. This research aids in understanding the solution behavior of conjugated organic materials. <br>
403

MECHANICS AND DESIGN OF POLYMERIC METAMATERIAL STRUCTURES FOR SHOCK ABSORPTION APPLICATIONS

Amin Joodaky (9226604) 12 August 2020 (has links)
<div>This body of work examines analytical and numerical models to simulate the response of structures in shock absorption applications. Specifically, the work examines the prediction of cushion curves of polymer foams, and a topological examination of a $\chi$ shape unit cell found in architected mechanical elastomeric metamaterials. The $\chi$ unit cell exhibits the same effective stress-strain relationship as a closed cell polymer foam. Polymer foams are commonly used in the protective packaging of fragile products. Cushion curves are used within the packaging industry to characterize a foam's impact performance. These curves are two-dimensional representations of the deceleration of an impacting mass versus static stress. The main drawback with cushion curves is that they are currently generated from an exhaustive set of experimental test data. This work examines modeling the shock response using a continuous rod approximation with a given impact velocity in order to generate cushion curves without the need of extensive testing. In examining the $\chi$ unit cell, this work focuses on the effects of topological changes on constitutive behavior and shock absorbing performance. Particular emphasis is placed on developing models to predict the onset of regions of quasi-zero-modulus (QZM), the length of the QZM region and the cushion curve produced by impacting the unit cell. The unit cell's topology is reduced to examining a characteristic angle, defining the internal geometry with the cell, and examining the effects of changing this angle.</div><div>However, the characteristic angle cannot be increased without tradeoffs; the cell's effective constitutive behavior evolves from long regions to shortened regions of quasi-zero modulus. Finally, this work shows that the basic $\chi$ unit cell can be tessellated to produce a nearly equivalent force deflection relationship in two directions. The analysis and results in this work can be viewed as new framework in analyzing programmable elastomeric metamaterials that exhibit this type of nonlinear behavior for shock absorption.</div>
404

A data-driven discrete elastic rod model for shells and solids

Patarroyo, Keith Y. 12 1900 (has links)
Les structures en forme de tige sont omniprésentes dans le monde aujourd'hui. Désormais, prédire avec précision leur comportement pour l'ingénierie et les environnements virtuels est indispensable pour de nombreuses industries, notamment l'infographie, l'animation par ordinateur et la conception informatique. Dans ce mémoire, nous explorons un nouveau modèle de calcul pour les tiges élastiques qui exploite les données de simulation pour reproduire les effets de coque et de solide présents dans les tiges qui brisent les hypothèses de la théorie classique de la tige de Kirchhoff, présentant ainsi une voie d'amélioration possible pour de nombreux états de l'art techniques. Notre approche consiste à prendre un ensemble de données de simulations à partir de solides volumétriques ou de coques pour former un nouveau modèle d'énergie définie positive polynomiale d'ordre élevé pour une tige élastique. Cette nouvelle énergie élargit la gamme des comportements des matériaux qui peuvent être modélisés pour la tige, permettant ainsi de capturer une plus large gamme de phénomènes. Afin de proposer et tester ce modèle, nous concevons un pipeline expérimental pour tester les limites de la théorie linéaire des tiges et étudier les géométries d'interface entre les cas coque à tige et volume à coque pour observer les effets d'un modèle de matériau non linéaire et une section transversale non elliptique dans la déformation de la tige. Nous étudions également la relation entre la courbure de la tige et la déformation de la section transversale et la courbure pour introduire une modification sur le terme de flexion de l'énergie. Cela nous permet de reproduire à la fois le comportement de flexion asymétrique présent dans les poutres volumétriques minces et les poutres à coque avec des sections transversales non convexes. Des suggestions pour de nouvelles améliorations des modèles et des techniques expérimentales sont également données. / Rod-like structures are ubiquitous in the world today. Henceforth accurately predicting their behavior for engineering and virtual environments are indispensable for many industries including computer graphics, computer animation, and computational design. In this thesis we explore a new computational model for elastic rods that leverages simulation data to reproduce shell and solid-like effects present in rods that break the assumptions of the classical Kirchhoff rod theory, thus presenting a possible improvement avenue to many states-of-the-art techniques. Our approach consists of taking a data set of simulations from both volumetric solids or shells to train a novel high-order polynomial positive-definite energy model for an elastic rod. This new energy increases the range of material behaviors that can be modeled for the rod, thus allowing for a larger range of phenomena to be captured. In order to propose and test this model, we design an experimental pipeline to test the limits of the linear theory of rods and investigate the interface geometries between the Shell-Rod and Volume-Shell cases to observe the effects of a nonlinear material model and a non-elliptical cross-section in the rod deformation. We also investigate the relation between rod curvature and deformation of the cross-section and curvature to introduce a modification on the bending term of the energy. This allows us to reproduce both the asymmetric bending behavior present in thin volumetric solid and shell beams with non-convex cross-sections. Suggestions for further improvements in models and experimental techniques are also given.
405

Vícepodlažní administrativní budova ve Zlíně / The multistorey office building

Bílek, Tomáš January 2012 (has links)
Design of a new steel structure administrative building in Zlín. Structure is consist of three parts. The part A is designed of three fields in the transverse direction and five fields in the longitudinal direction. This part is two-storey. The part B is designed of two fields in the transverse direction and three fields in the longitudinal direction. This part is six-storey (five-storey). The part C is designed of two fields in the transverse direction and five fields in the longitudinal direction. This part is four-storey (three, two-storey). In both directions in all parts of the building is the distance between the columns in all fields of 6,0 meters. Structural elevation of all floors is 3,5 meters. Shape and dimension design. Fixed, utility, climatic load. The purpose is confrontation of inner forces and dimensioning of main supporting elements in three variations of structure. Comparsion of variations. More detailed static calculation, drawings for the selected variant. Detailed drawings for part of building.
406

adix_Masters_thesis_FINAL.pdf

Adam John Dix (14210324) 05 December 2022 (has links)
<p> Wire-wrapped rod bundles are often used in nuclear reactors operating in a fast neutron spectrum, as designers seek to minimize neutron scattering by packing the fuel pins into a hexagonal lattice. Bundles with many rods have extensively been studied as representative of large fuel assemblies, however far fewer experiments have investigated bundles with 7 rods (7-pin bundles). The large difference in subchannel number between these bundles leads to 7-pin bundles having different pressure drop characteristics. The Versatile Test Reactor (VTR) sodium cartridge loop proposes to use a 7-pin bundle as its experimental core region, highlighting the need for additional data and models. The current work seeks to establish a better understanding of the pressure drop in 7-pin wire-wrapped rod bundles through scaled experiments and a novel pressure drop model. A scaling analysis is first performed to demonstrate the applicability of water experiments to the VTR sodium cartridge loop, before an experimental test facility is designed and constructed. Experiments are then performed at a range of Reynolds numbers to determine the pressure drop. Current models are able to predict the data well, but are complex and can be difficult to use. A comparatively simpler model is developed, based on exact laminar solutions of a simplified rod bundle, which also offers a theoretical lower bound for the pressure drop in wire-wrapped bundles. The proposed model compares well with the existing experimental database, able to predict bundle friction factor with an average absolute percent difference of 10.8%. This accuracy is also similar to existing correlations, while relying on fewer empirical coefficients. The theoretical lower bound is also used to identify several datasets in literature that may feature data that is systemically lower than the true pressure drop, which agrees with previous observations in literature. </p>
407

Formoptimierte filigrane Stäbe aus UHPC und korrosionsfreier CFK-Bewehrung für variable räumliche Stabtragwerke

Henke, Michael, Fischer, Oliver 21 July 2022 (has links)
Die Vision bei diesem Projekt bestand darin, zukünftig anstelle massiver Betontragsysteme mit meist ungleichmäßiger Materialausnutzung am Kraftfluss orientierte, filigrane, stabartige Tragwerke zu entwerfen, die sich neben der Gewichtsreduktion und einer höheren Transparenz auch durch eine bessere Ressourcennutzung auszeichnen. Dabei wurde eine modulare Bauweise angestrebt, bei der die Einzelkomponenten Druckstab und vorgespannter Zugstab sowie Teile des Verbindungsknotenelements vorgefertigt und am Einsatzort zusammengefügt werden. Sowohl im Hinblick auf die Tragfähigkeits- und Verbundeigenschaften als auch auf die Dauerhaftigkeit sollten die Stäbe aus faserverstärktem Ultrahochleistungsbeton (UHPFRC) hergestellt sowie ausschließlich mit nichtmetallischen Elementen aus faserverstärkten Kunststoffen (FVK) bewehrt bzw. vorgespannt werden. Im geförderten Zeitraum lag das Hauptaugenmerk auf der Entwicklung filigraner, formoptimierter Druck- und vorgespannter Zugstäbe. Zum Knotenelement wurden theoretische Überlegungen sowie erste Tastversuche angestellt. [Aus: Projektidee und Zielsetzung] / The vision of this project was to replace massive concrete structures with mostly inhomogeneous material utilization in the future by designing filigree concrete truss supporting structures in accordance with the principle form follows force instead. Thus, besides weight reduction and a higher transparency also a higher resource efficiency can be achieved. A modular construction method, in which the components compression strut, prestressed tie and connection joint elements are prefabricated and joined together at the construction site, was aspired. With regard to load-bearing capacity and bonding behaviour as well as durability, the struts and ties are made of Ultra-High Performance Fibre-Reinforced Concrete (UHPFRC) and are reinforced or prestressed exclusively with non-metallic elements made of f bre-reinforced polymers (FRP). Within the funding period, the focus was on the development of f ligree, shape-optimized struts and prestressed ties. Regarding the connection joint element, theoretical considerations were made and first basic tests were carried out. [Off: Vision and objective]
408

Kořeny moravské urbanistické struktury / Roots of Moravian Urban Structure

Mohelník, Ladislav Unknown Date (has links)
The thesis has been written on the basis of main architectural concepts and their application in real life within a historical context investigation. Main architectural concepts are represented in a harmony of architectural composition that deals with relations among form, structure and space in the unique art work. Genius loci play very important role in the architectural creation - it represents a special and extra-ordinary urban locality and its architectural value in the historical, geographical and cultural context. The origin of Ostravice village within the historical frame concept of Moravia domain is the topic of this thesis. Other historical documents gave information about Bruneswerde as the Brno Castle. That means Brno Castle had to be founded not in Brno (as it has been consid-ered for many years) but it was located in Beskydy at Ostravice. The sacred city – Civitas Dei had been located in Bruneswerde region in early ages as the centre of European culture, education and spiritual life. Civitas Dei – divine Jerusalem in the transcription of St. Augustine's book De civitate Dei – is not only glorification of God and religious fantasy. It is also one of significant clues for recognition of historical architecture. The depiction of unknown settlement from the book of unde-fined origin is a superb testimony about extinct architectural works. They are legible from cadastral maps. Brno Castle - residence of nobility and power served shelter to St. Vojtěch, St. Prokop, St. Václav and St. Ludmila as it is obvious for the mentioned picture. Three major temples, three com-position axes symbolized by three towers on coins are in analogical relation to Brno triangle of four saints - the Saint family of Brno temples. Powerful ambitions of Brno City principals and clergy are inscribed into the urban structure in the way of composition relations which are legible to them who devoted themselves to the mystery of harmony. The absence of historical continuity affects personal attitudes and also identity of the whole community. The architecture truly reflects the past state of polis and it is eloquent even after its death. The architectural composition relations influence the natural environment for long time, longer than the architectural work existence. The geometric order of Renaissance Brno existence has not been in attention of architects so far. The features were discovered in characteristic paintings by Albrecht Durer. They are evidently secret works of the genius. A meaningful collaborator and follower in the extensive project was also his friend Jan Čert from Brno and lately from Vienna. His noble genealogy played a significant role in history of Silesia and Moravia for centuries. It is tendency to consider him as Austrian or even German architect. It is because of the fact that the genealogy tree of his noble family had roots in Moravia. It is supposed that Durer with Jan Čert´s support created the extraordinarily monumental architectural and urban works in Brno. A remarkable consensus in the urban composition of two squares and transition of traditional urban structure of Ostravice Civitas Dei into the modern Brno is also confirmed due to the identification of noble creators and owners, who were at the foundation, transformation and extinction of elements of the Moravian urban structure.

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