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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.
11

Asfaltové směsi s vyšší životností za použití R-materiálu / Bituminous mixtures with a higher lifetime using recycled asphalt

Stromecký, Roman January 2019 (has links)
This diploma thesis deals with a project of asphalt mixtures with high stiffness modulus using R-material. The theoretical part describes the characteristics of these mixtures in the Czech Republic and in Switzerland. Further this part deals with the use of R-material in the Czech Republic and chosen other countries of the world, it also deals with the ways of recycling roads. The theoretical part also deals with the testing methods used. In the practical part two new asphalt mixtures of the high stiffness modulus type with the addition of 25 % R-material are suggested. As a base for these two mixtures a mixture of the high stiffness modulus type, which was taken from an asphalt mixing plant, was used. Tests were run on the binders and several functional tests (stiffness modulus, fatigue resistance, low temperature qualities) wer done on the suggested asphalt mixtures and also the mixture taken from the mixing plant. Consequently, the results were compared. The conclusion of the thesis is devoted to modelling a construction of a road using the program LayEps, which verified if the suggested mixtures could reduce the thickness of roads.
12

Inovativní asfaltové směsi pro netuhé vozovky s použitím R-materiálu / Inovative asphalt mixtures to flexible pavement structure with using reclaimed asphalt

Horáček, Daniel January 2020 (has links)
The diploma thesis is focused on the design and production of two innovative asphalt mixtures of the VMT 22 type into the base asphalt course. The newly produced blends contain modified binders, such as polymer modified bitumen (PMB) and Crumb rubber modified bitumen (CRMB). The theoretical part of the thesis describes the current state of the use of Reclaimed asphalt pavement in the base asphalt course. Furthermore, there are described types of asphalt mixtures for the base asphalt course are used in the Czech Republic and other countries. The conclusion of the theoretical part is devoted to the description of Reclaimed asphalt pavement (RAP), its storage and processing in a hot mix center. In the practical part of this thesis, there is described design and test of two High modulus asphalt mixture VMT 22, into which 25% RAP is dosed cold without rejuvenators. These asphalt mixtures are then subjected to functional tests (Stiffness of asphalt mixture test, Resistance to fatigue test, Low temperature properties of asphalt mixture test). The results of the functional tests are compared with the functional requirements in the Czech regulation TP 151. In the end of this thesis it is verified by means of the LayEps software that a suitable design of the asphalt mixture can significantly extend the road life.
13

Entwicklung eines Befestigungssystems für Photovoltaikmodule

Tautenhahn, Lutz 30 January 2015 (has links)
Der derzeitige technische Fortschritt stützt sich maßgeblich auf die Nutzung von elektrischem Strom. Der Anteil der Stromerzeugung aus Sonnenlicht hat mittlerweile in Deutschland den der Wasserkraft überschritten, der 1990 noch der größte regenerative Energielieferant war. Die Technologie der Photovoltaik (PV) wandelt die hochenergetische Strahlung der Sonne in elektrischen Strom um und nutzt dabei häufig Glasplatten als tragende Struktur. Der Hauptanspruch dieser Arbeit liegt in der Entwicklung und Untersuchung eines Befestigungssystems mit einer höher- oder hochmoduligen Klebverbindung zum gläsernen PV-Modul sowie einer möglichst universell einsetzbaren Fügeverbindung zur Unterkonstrukion. Die systematische Enwicklung der Fügeverbindung zum PV-Modul basiert auf dem Ansatz eines flexiblen, stützenden \\hbox{Ringes} für das Fügeelement (Halter), um die durch eine mechanische Belastung der Module induzierten Zugspannungen im Glas über der Fügeelementkante zu reduzieren. Eine neuartige, kombinierte Klammer-Keil-Verbindung sichert die Befestigung auf einer von ihr unabhängigen Unterkonstruktion sowohl quer als auch längs zur Schienenrichtung. Experimentelle Arbeiten charakterisieren die eingesetzte Klebverbindung unter verschiedenen Beanspruchungsszenarien, um sowohl konstruktions- als auch klebstoffbedingte Möglichkeiten und Grenzen der Fügeverbindung für die vorliegende Anwendung zu identifizieren. Die Untersuchungen weisen zudem geeignete Vorbehandlungsmaßnahmen der Aluminiumoberflächen aus. Sowohl numerische Simulationen als auch die neuartig eingesetzte Nahbereichsphotogrammetrie bestätigen in Bauteiluntersuchungen die vorteilige Wirkung des flexiblen, höhermodulig geklebten Ringes. Die vorliegende Arbeit setzt sich hierbei auch kritisch mit unterschiedlichen Einflüssen auf die Ergebnisse auseinander, die einerseits durch verschiedene Prüfstände hervorgerufen werden können und andererseits auch den verwendeten Methoden zugrunde liegen. / Today much of technical advances are due to the usage of electricity. The contribution of solar power to the production of electricity in Germany currently surpasses water powered electricity which was in 1990 the almost exclusive renewable energy source. The technology of photovoltaic systems based on high-powered sun radiation, often utilizes glass plates as a supporting structure. This dissertation primarily focuses on the research and development of a mounting system with a higher or high modulus adhesively bonded joint to the PV-module as well as an all-purpose connection to the substructure. The systematical development process of the connection to the PV-module is based on the approach of a flexible supporting ring-shaped mounting element. This reduces the tension within the glass surface at the edge of the mounting element when mechanically loading the PV-module. A novel connection using a clamp-wedge combination ensures the ability to mount the PV-module horizontally or vertically to the rail substructure. Through the development process, the bonded joint is exposed to various scenarios where the construction as well as the adhesive possibilities and limitations under each scenario are analyzed. Research outcomes yield recommendations for appropriate pre-treatment of the aluminum surfaces. Numerical simulations as well as the novel use of the near-field photogrammetry method confirmed beneficial action of the flexible ring-shaped mounting element within assembly testing of large glass specimens. This dissertation discusses how different variables can have a considerable effect on results when introduced through the testing device and through monitoring methods.

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