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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.
371

Vysoce entropické slitiny Cantorova typu zpevněné disperzí nitridů / Nitride dispersion strengthened Cantor´s high entropy alloys

Havlíček, Štěpán-Adam January 2020 (has links)
High Entropy Alloy (HEA) is a class of construction steels based on the mixing of five or more elements in approximately equimolar ratios. Despite the ambiguity of their future use, HEAs represent a significantly new group of construction materials that are currently receiving a great deal of attention. Single-phase HEAs fail when used at elevated tempera-tures. The improvement of their high-temperature resistance was achieved by introducing a dispersion of oxides Al2O3 and Y2O3. To generalize the positive effect of dispersions on the mechanical properties at elevated temperatures, particles of a similar nature were cho-sen. These were dispersed particles of nitrides: hardness-incompatible AlN and hardness-compatible BN. The particles were evenly distributed inside the alloys by mechanical al-loying and compacted by SPS (Spark Plasma Sintering). The new structural alloy reached a density higher than 96.5 % and brought an increase in yield strength at room tempera-ture of up to 67 % and 40 % at elevated temperatures, while maintaining a homogeneous distribution of input powders.
372

Experimentální zkoušky vyztužených a zesílených betonových deskových prvků / Experimental tests of reinforced and strengthened concrete slab elements

Lisztwan, Dominik January 2021 (has links)
This diploma thesis analyses behaviour of reinforced concrete slabs and their strengthened variants. Their comparison is determined by the results from the experimental load test. Outcomes are accompanied by the results gained from the analytical calculation according to valid codes and requirements and also nonlinear finite element method analysis.
373

Experimentální a numerická analýza zesílení železobetonových prvků / Experimental and numerical analysis of reinforced concrete elements

Niedoba, Jakub January 2021 (has links)
This master‘s thesis deals with the behaviour of strengthened reinforced concrete beams. The aim was to evaluate different types of strengthening in comparison not only with each other, but also with the reference beam. Three reinforced concrete beams were fabricated for the purpose of the thesis. The first served as a reference beam, the second was strengthened with carbon lamella glued to the lower edge of the reinforced concrete beam, and the last one was strengthened with unbonded post-tensioning system. Subsequently, they were all loaded by a four-point bending. An evaluation was then carried out which shows that the two strengthened reinforced concreate beams resist the load much better than the reference beam. In the conclusion, different utilization possibilities of both methods are listed, as well as the disadvantages that must be taken into account when designing.
374

Zesilování ocelových nosníků výztuží na bázi FRP / Strengthening steel beams using reinforcement based on FRP

Bláha, Tomáš January 2013 (has links)
A study of an influence of strengthening steel beams using reinforcement based on FRP on a moment bearing resistance and bending stiffness. Evaluation of the theoretical calculation methods based on the performed experimental verification. Description of the production of carbon fibres and composite materials on the basis of carbon fibres.
375

Rekonstrukce zděné budovy / Restoration of masonry building

Hubený, Radim January 2017 (has links)
The final thesis is focused on restoration masonry building. Concretely assessment of resistance joist's floors, design alternative's strengthening and impact of surcharge on pronounces constructions. The choice one of alternatives strengthening, design and check of floor structure over the second floor.
376

An investigation into home and community based health care programmes in Zimbabwe : an analysis of the congruency of service users' needs and the programme goals

Mataure, Priscilla Nkosazana 30 January 2014 (has links)
The past two decades have witnessed transition from in-patient hospital settings to Community and Home Based Care in Zimbabwe. This is because of an increase in the number of people developing chronic health conditions such as diabetes, hypertension and cancers, and thus needing longer treatment durations. The increase in chronic conditions has mainly been attributed to the increase in incidence and prevalence of Human Immunodeficiency Virus and Acquired Immune-deficiency Syndrome in Sub-Saharan Africa. Many Governments, including that of Zimbabwe, endorsed and promoted community and home based care to provide a continuum of care to the chronically ill. Despite the implementation of Community and Home Based Care programmes, no studies known to the researcher have been done to investigate the congruency of service users’ needs and the programme goals. Purpose: The purpose of the study is twofold; firstly to explore whether Community and Home Based Care interventions provide services that effectively meet users’ goals in a dynamic social environment and secondly, to develop guidelines for enhancing care provision as well as congruency of service users’ needs and programme goals. Methods: A mixed-method approach combining qualitative and quantitative data collection and analysis was used. Concurrent collection of data with equal status was placed on both qualitative and quantitative data. For qualitative data interviews and focus groups were used with home based care service users, family care givers, and health providers. Structured questionnaires were used for the quantitative data. Framework: Imogene King’s Interacting Systems Framework and Theory of Goal Attainment were adopted to guide the study. These were utilised because of the assumption that mutual agreement on goals for effective care can be achieved through nurse-client interactions and communication Research findings: Community and Home Based Care programme in Zimbabwe does not comprehensively meet the needs of its service users. Service users have diverse needs and goals depending on the specific condition and symptoms they experience. They perceive access to medication for symptom management and pain control, food and financial stability, as priority needs. The study found that nursing services provided in Community and Home Based Care generally align with the physical needs of service users and was deficient in addressing the socio-economic and psycho-social needs of service users. Conclusion: No single sector can achieve the users’ and the programme`s goals of quality health on its own. The goals may only be realised when other stakeholders and relevant sectors contribute to the Community and Home Based Care programme, which requires diverse resources. Guidelines to enhance integration of Community and Home Based Care with social services were developed. / Health Studies / D.Litt. et Phil. (Health Studies)
377

Microstructure evolution and strengthening mechanism in Ni-based composite coatings: Microstructure evolution and strengthening mechanism in Ni-based composite coatings

Sadeghi, Amir 28 September 2016 (has links)
Ni electrodeposition is a suitable process for producing thick deposits and thick metallic microstructures, especially for producing relatively deep micromoulds in Microsystems industry. Ni-P deposits, due to their better properties compared to Ni deposits – particularly high mechanical properties (hardness, wear resistivity), corrosion resistance, magnetic properties, a higher fatigue limit and lower macroscopic deformation – can be a very good alternative for producing Microsystems, especially for MEMS or Microengines. According to few limited literature and our primary investigations, dispersion coating and adding particle into the electrolyte can be considered as an approach in order to decrease the stress and ease the deposition of Ni-P galvanically. Although in the last decades the influence of particles embedment in the matrix by electroplating techniques have attracted the scientific interest, there are still contradictions among the research community concerning the influence of codeposited particles on the microstructure and strengthening properties of Ni-based composites coatings. In many cases, it is believed that the enhanced mechanical performance of the coatings is mainly caused by a change in the microstructure of the metal matrix and not so much by the presence of the particles themselves. In other words, the role of particle characteristics - like their nature, size and concentration - on the layer features and strengthening mechanism of electrodeposited Ni-based composite coating with different matrix is not cleared well. Furthermore, the incorporation of particles into the deposit is mainly considered as a key factor for determining the composite coatings properties. Despite of existing models of ECD, the mechanism of particle incorporation into the film under influence of different particle characteristics has not been well understood yet. Therefore, the main aim of this study is to shed light on the effect of particle characteristics (size, concentration, type) on the codeposition process, microstructure and strengthening mechanisms in Ni and Ni-P electrodeposited composite coatings.
378

Tragwerke aus Textilbeton - numerische Strukturanalyse

Steinigen, Frank, Sickert, Jan-Uwe, Hoffmann, Andreas, Graf, Wolfgang, Kaliske, Michael January 2011 (has links)
Der Beitrag gibt einen kompakten Überblick zur Leistungsfähigkeit und Anwendbarkeit der in den Teilprojekten D2-Numerische Simulation, E3-Sicherheitsbeurteilung und E4-Numerische Langzeitprognose des Sonderforschungsbereichs 528 entwickelten Algorithmen und Programmlösungen. Die gezeigten Methoden sind praxistauglich aufbereitet und stehen zur Anwendung für die Analyse des Kurz- und Langzeit-Tragverhaltens von Textilbetonstrukturen zur Verfügung. / The paper provides a compact summary of the ability and applicability of the algorithms and software packages developed in the project parts D2-Numerical Simulation, E3-Reliability Assessment und E4-Numerical Long-term Prognosis of the Collaborative Research Centre 528. The presented methods are prepared for practical use and are available for the analysis of the short- and longterm load-bearing behaviour of textile reinforced concrete structures.
379

Berechnungsalgorithmus zur Bestimmung der Verankerungslänge der textilen Bewehrung in der Feinbetonmatrix

Lorenz, Enrico, Ortlepp, Regine 03 June 2009 (has links)
Dieser Beitrag befasst sich mit der experimentellen und analytischen Bestimmung der Verankerungslängen textiler Bewehrungsstrukturen einer Textilbetonverstärkungsschicht. Die experimentelle Untersuchung des Verbundverhaltens erfolgte anhand von Pull-Out-Versuchen. Die analytische Betrachtung des Verbundproblems geschieht aufbauend auf multilinearen Lösungen der Verbunddifferentialgleichung anhand der experimentell ermittelten Kraft- Rissöffnungs-Beziehungen. Mit Hilfe eines separaten Modells wird aus der so ermittelten Verbundspannungs-Schlupf-Beziehung (VSB) die zur Verankerung einer entsprechenden Kraft F erforderliche Verankerungslänge lE bestimmt. Die Überprüfung der Berechnung erfolgt anhand von unabhängig in experimentellen Versuchen zur Bestimmung der Verankerungslänge ermittelten Werten. Es konnte eine gute Übereinstimmung der berechneten mit den versuchstechnisch bestimmten Verankerungslängen festgestellt werden.
380

Textilbewehrter Beton als Torsionsverstärkung

Schladitz, Frank, Curbach, Manfred 03 June 2009 (has links)
Anhand von Versuchsergebnissen wird gezeigt, dass Stahlbetonbauteile mit textilbewehrtem Beton verstärkt werden können. Sowohl die Torsionstragfähigkeit als auch die Gebrauchstauglichkeit werden durch die textilbewehrte Verstärkungsschicht deutlich verbessert. Vergleichsrechnungen zeigen, dass die Torsionstragfähigkeit mit bereits bekannten Stabwerksmodellen ermittelt werden kann.

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