• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 172
  • 103
  • 57
  • 33
  • 18
  • 12
  • 10
  • 8
  • 6
  • 5
  • 5
  • 4
  • 4
  • 2
  • 1
  • Tagged with
  • 513
  • 170
  • 85
  • 58
  • 55
  • 45
  • 45
  • 44
  • 42
  • 42
  • 41
  • 38
  • 36
  • 35
  • 34
  • 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

Vliv chemického složení, licí teploty a použité dezoxidace na technologické vlastnosti austenitických chromniklových ocelí / Influence of chemical composition, casting temperature and the used deoxidation on technological properties of austenitic chrome-nickel steels

Myška, Martin January 2017 (has links)
The thesis deals with austenitic stainless steel ČSN 42 2930, ASTM A351 CF8 and evaluates its mechanical and technological properties. The first part of this work is focused on properties of austenitic steels, it describes the process of melting and casting of steel on the basis of the realized experiments. It also deals with the mechanical properties of the used steel. The second section of the thesis is dedicated to the historical development of the maximum fluidity tests and main factors affecting the maximum fluidity of alloys. Maximum fluidity values have been processed on the basis of different casting temperatures of the maximum fluidity tests of the used steel. The third part of the work examines the effect of the casting temperature on the feeding distance of the used steel as well as the influence on its shrinkage rate.
402

Studium vlivů ovlivňujících životnost cementobetonových krytů v ČR / Study of impacts affecting the lifetime of cement concrete coverings in the Czech Republic

Láznička, Josef January 2019 (has links)
This thesis deals with the study of cement – concrete coverings. The aim of the thesis is a summary of current knowledge of these constructions. The experimental part of this paper deals with the design of concrete for the lower layer of cement – concrete cover. Emphasis is placed on the elimination of microcracks and to increase the lifetime of these construction.
403

Three essays on unveiling complex urban phenomena: toward improved understanding

Lym, Youngbin 13 November 2020 (has links)
No description available.
404

Výzkum příčin vzniku poruch betonových prvků typu Face Block / The research of cause of failure of concrete elements Face Block

Eger, Lukáš January 2014 (has links)
This master thesis focus on the analysis of effects that cause defects in concrete blocks. Experiences show that the defect of the blocks are often manifested in the form of cracks. Great rate of occurrence of defects is attributed to volume changes of poor quality concrete filler. The aim of this master thesis is to analyze the finding from the practical use and exploration of the requirements for the actual blocks and especially the concrete filler which is used to make monolithic structures built from these blocks. The attention will be paid to the interaction between the block and the concrete filler. Here we focus mainly on the volume changes caused by a change of moisture level and especially the cyclic moisture.
405

Návrh silničního ocelobetonového mostu v Trenčíně / Design of steel-concrete composite structure of road bridge in Trenčín

Doležal, Tomáš January 2015 (has links)
The aim of diploma thesis was to design alternative of composite road bridge in Trenčín. The bridge beam is designed as continuous with theoretical span of 65 m + 106 m + 65 m. Permanent load, climatic load (uniform and nonuniform temperature variation, windload), shrinkage, differential settlement and traffic load were taken into consideration according to Eurocodes. Technical report, static report, drawings, bill of quantities are included. Computational model for evaluation of internal forces was carried out in SCIA Engineer software.
406

Nosná železobetonová konstrukce / Load-bearing reinforced concrete construction

Klajba, Daniel January 2015 (has links)
The aim of diploma thesis is to design monolithic reinforced concrete underground structure, which is partly under existing building and partly will form the basis of a new outbuilding. Structure is designed as white tub, whitout any additional isolations against water a ground humidity. All structure elements (slabs, walls, beams) was designed according to standard ČSN EN 1992-1-1 for ultimate and serviceability limit state. Structural analysis was performed using Scia Engineer 2013 – Student version. The results were validated by simplyfied manual method.
407

Možnosti uplatnění moderních metod při výrobě prototypových odlitků / Possibilities of using modern methods in manufacturing of prototype castings

Šmíd, Jiří January 2011 (has links)
The introduction part of the thesis focuses on the overview of rapid prototyping in foundry industry. Principles of the most important RP methods are described and the FDM method is analyzed in more detail. This method was used in the practical part for the production of wax patterns with silicone moulds. The wax patterns were used for the production of castings using the lost wax method. The result of this work is determination of dimensional changes during the whole process of casting manufacture from the drawing to the final casting.
408

Vliv přísad na vlastnosti metakaolinového geopolymeru / Effect of admixtures on the properties of metakaolin geopolymer

Halasová, Kristýna January 2017 (has links)
Geopolymers are amorphous to semi-crystalline aluminosilicate polymers which are formed from inorganic polycondensation reaction of a solid aluminosilicate precursor with an alkaline sodium hydroxide or silicate. The resulting materials exhibit high durability, resistance to aggressive environments, high temperature resistance and many other properties that make them have received much attention in recent years, not only in construction. This thesis describes the influence of additives commonly used in concrete and mortar (water reducing, superplasticizer, air-entraining, foamer and defoamer, anti-shrinkage, stabilization) on the behavior of metakaolin in geopolymer fresh and hardened state. It describes metakaolin geopolymer effect on rheological properties of fresh mixtures, compressive strength and flexural strength after 28 days and a density in the fresh and hardened state.
409

Characterization and valorization of secondary quality hardwood as structural material / Caractérisation et valorisation des feuillus de qualité secondaire comme matériau structurel

Purba, Citra Yanto Ciki 12 April 2019 (has links)
Afin de valoriser au mieux le bois de feuillu de qualité secondaire, il est important de comprendre ses propriétés et d'optimiser ses propriétés mécaniques. La variabilité de certaines propriétés structurelles, physiques et mécaniques du bois de hêtres et de chênes issus d’éclaircis a été étudiée. Des billons tirés de ces arbres ont été déroulés en trois épaisseurs (2.1, 3, and 4.2 mm). La qualité du placage a été évaluée en mesurant la proportion du nœud et les fissurations. Les propriétés mécaniques du LVL (lamibois) réalisé à partir de ces placages ont été mesurées par méthode destructive et non destructive. Chez les deux espèces, le bois juvénile est concentré dans une petite zone près de la moelle, de sorte qu'il y aura peu ou pas de bois juvénile déroulé. Les propriétés mécaniques et physiques du bois des deux espèces sont fortement influencées par sa densité. Le placage de 3 mm d'épaisseur a fourni les propriétés mécaniques optimales pour le LVL pour les deux espèces. Ces propriétés mécaniques sont comparables à celles de LVL réalisés à partir d'autres essences de feuillus. Le placage interne a fourni du LVL avec une densité plus élevée, mais des propriétés mécaniques plus faibles en raison de sa proportion de nœuds plus élevée. / To improve the value of secondary quality hardwood, it is important to understand its wood properties and optimize its mechanical properties. The variability of some structural, physical and mechanical properties of wood from beech and oak trees issued from thinning was studied. Logs from these trees were rotary peeled in three different veneer thicknesses (2.1, 3, and 4.2 mm). Veneer quality was assessed by measuring the veneer knot proportion and checking properties. The mechanical properties of LVL (laminated veneer lumber) made from these veneers were measured using the static and dynamic method. Juvenile wood in both species is concentrated in a very small area near the pith thus there will be no or low part juvenile wood peeled. The wood mechanical and physical properties of both species were strongly influenced by the wood density. The 3 mm thick veneer provided the optimal mechanical properties for LVL for both species. Such mechanical properties are comparable to LVL made with other hardwood species. The internal veneer provided LVL with higher density, but lower mechanical properties as a result of its higher proportion of knots.
410

Freiräume in schrumpfenden Städten: Chancen und Grenzen der Freiraumplanung im Stadtumbau

Rößler, Stefanie 11 May 2009 (has links)
Schrumpfungsprozesse bestimmen seit Ende der 1990er Jahre zunehmend die Stadtentwicklung in den Neuen Bundesländern. Demografischer und ökonomischer Wandel gelten als wesentliche Ursachen für einen massiven Nachfragerückgang und erhebliche Leerstände im Wohnungsbestand. Im Zuge des Programms "Stadtumbau Ost“ werden die ungenutzten Wohngebäude abgerissen. Sowohl in Stadtzentren als auch in Randlagen erstrecken sich nicht mehr bebaute Areale, da sich nur für wenige Freiflächen eine bauliche Nachnutzung findet. Freiraumplanerische Konzepte und Maßnahmen werden möglich, aber auch notwendig für den Umgang mit den frei gewordenen Flächen und bieten gleichzeitig Potenziale zur Verbesserung der städtischen Umwelt- und Lebensqualität. Die vorliegende Forschungsarbeit beschäftigt sich mit der Frage, welche Bedeutung Freiräume im Umgang mit räumlichen Schrumpfungsprozessen haben und wo die Chancen und Grenzen der Freiraumplanung beim Stadtumbau liegen. Die Autorin legt die gegenwärtigen Rahmenbedingungen der Freiraumplanung dar und setzt sich mit Stadtmodellen, städtebaulichen Leitbildern und dem Verständnis von Natur und Landschaft in der schrumpfenden Stadt auseinander. Am Beispiel der Großstädte Chemnitz, Halle und Leipzig werden die Strategien, Entscheidungen und Handlungsansätze der Freiraumplanungspraxis schrumpfender Städte analysiert. Die Ansätze werden beschrieben und mit Blick auf ihre Eignung und Zukunftsfähigkeit für die Gestaltung des Stadtumbauprozesses diskutiert. / Since the second half of the 1990’s, the new federal states of Germany have undergone dramatic demographic and economic change, which, among other things, has led to the ongoing phenomenon of shrinking cities. The work at hand deals with the issue of what the relevance of urban green spaces is in light of the spatial shrinking processes and where the opportunities and limitations are concerning green space planning within urban restructuring.

Page generated in 0.0187 seconds