• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 110
  • 40
  • 26
  • 22
  • 12
  • 10
  • 9
  • 7
  • 5
  • 4
  • 3
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 299
  • 29
  • 26
  • 23
  • 21
  • 20
  • 18
  • 16
  • 14
  • 14
  • 14
  • 13
  • 13
  • 12
  • 12
  • 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.
281

Tailor-made heterofunctional poly(ethylene oxide)s via living anionic polymarization as building blocks in macromolecular engineering / Poly(oxyde d'éthylène)s hétérofonctionnels linéaires préparés par polymérisation anionique par ouverture de cycle et l'élaboration d'architectures macromoléculaires complexes

Pozza, Gladys 30 April 2014 (has links)
L'objectif principal de la thèse porte sur la synthèse contrôlée et la caractérisation d’architectures macromoléculaires complexes originales à base de POE. Les POEs α-undécènyle-ω-hydroxy sont obtenus par polymérisation anionique par ouverture de cycle de l’oxyde d’éthylène. Le groupement hydroxyle est modifié pour accéder à des POEs α-undécènyle-ω-méthacrylate et des POEs α-undécènyle-ω-acétylène. Ces premiers POEs sont ensuite utilisés pour préparer soit des POEs à structure en peigne par ATRP dans l'eau soit par l'intermédiaire de réaction « click », des POEs à structure en étoile tétrafonctionnelles, tandis qu’avec les seconds permettent d’obtenir des PI-b-POE par réaction « click » avec le polyisoprène ω-azoture. Les extrémités de chaîne de POE commerciaux α-méthoxy-ω-hydroxy sont modifiées en POEs α-méthoxy-ω-allyle ou en POEs α-méthoxy-ω-undécènyle pour synthétiser par réaction d’hydrosilylation des étoiles de POE à structures en étoile octafonctionnelles. / The main objective of the thesis focuses on the controlled synthesis and the characterization of original and complex macromolecular architectures based on PEO. α-Undecenyl-ω-hydroxy PEOs are obtained by anionic ring opening polymerization of ethylene oxide. The hydroxyl group is modified to access to α-undecenyl-ω-methacrylate PEOs and α-undecenyl-ω-acetylene PEOs. These first PEOs are used to prepare either comb-shaped PEOs by ATRP in water or through by click reaction of tetrafunctional star-shaped PEOs. Whereas the second PEOs allow obtaining block copolymers PI-b-PEO via click reaction with ω-azide polyisoprene. The chain-ends of commercial α-methoxy-ω-hydroxy PEO are modified in α-methoxy-ω-allyl PEOs or in α-methoxy-ω-undecenyl PEOs to synthesize by hydrosilylation reaction octafunctional star-shaped PEOs.
282

Akademické náměstí - Fakulta výtvarných umění / Academic Square - Faculty of Fine Arts

Novotná, Markéta January 2015 (has links)
The final thesis is focused on a design of architectural study of a Faculty of fine arts on the area, which is located on a border of two Brno districts Veveří and Žabovřesky. The chosen area is determined by Šumavská Street, Bulínova Street, and Veveří Street. The design follows an already processed part of the project from the first semester in the subject TG02. It is focused on the layout of the buildings in the area and the design of architectonical study for three out of four units – the Faculty of Forensic Engineering, common premises of both faculties and underground garages. The fourth unit, which is the Faculty of Fine Arts, is designed in the second phase as the final thesis. Other units are developed together with the design of the second faculty. The architectonical concept follows the city structure in the nearest surroundings. The main idea was to create a cluster of buildings which respects a human scale, not to create a long endless facades and gigantic masses of buildings. The solution is two L-shaped buildings, which grip the building of common premises. It creates a lot of semipublic and public spaces with a great variety of various functions.
283

Polyfunkční dům v Brně Medlánkách / Multifunctional building in Brno Medlánky

Písařík, Jan January 2013 (has links)
Master´s thesis “Multifunctional building in Brno Medlánky“ is processed in the form of project documentation. Multifunctional building is designed as a detached house with a flat roof. The object has four above-ground floors with no basement. In the object there are twelve flats and three shops altogether. The object is made of building system Porotherm.
284

Rekonstrukce mostu u obce Holýšov / Reconstruction of the road bridge near the village Holýšov

Svoboda, Adam January 2016 (has links)
The thesis deals with design of strengthening of existing bridge structure near the village Holýšov using modern method of additional presstresing. The bridge over the river of Radbuza is h-shaped beam bridge, which was built in 1924. In the present state its load capacity is under the limits for bridges situated on first-class roads. Original documentation of the bridge does not exist, the main source of information about construction details is the diagnostics research. The method of reinforcement by post-tensioning by cables in substituted cable ducts is highly efective in terms of the incerease the load capacity of existing bridge structure. The design of strengthening and the final load capacity was verified by static calculation.
285

Horský penzion s wellness / Mountain Hotel with Wellness

Kopečková, Kristýna January 2017 (has links)
The subject of my thesis is the design mountain guesthouse with a wellness centre, which is located in the village of Mala Morávka, at the level of documentation for construction. The new building is located in the cadastre unit Karlov pod Pradědem. This is a two floors, slab-building L-shaped with separate parking for visitors of boarding house and wellness centre. The structural system is composed of ceramic blocks Porotherm and reinforced concrete joist floor. Roof structure is made up of wooden trusses girders saddle shape. Design of mountain guesthouse with wellness centre respects the territorial plan of the village of Malá Morávka.
286

Nový pavilon SOU Písek / New pavilion SOU Písek

Troup, Tomáš January 2017 (has links)
Diploma thesis deals a project documentation of a new school pavilion SOU in the location Pisek because of the unsatisfactory existing school bulding, which is located at a small distance from the new pavilion. Investor wants to build a new object of universal classrooms for ca. 180 students and sports hall with hygienic and technical facilities, which will be able for football club FC Pisek (football fields and central object of FC Pisek are close to neighboring plots). Investor wants to let the school canteen be on the current place, which is north of the new object. The object is designed as a two-floor with roof ascent (3.NP terrace), part of the building is embedded in the ground. The structural system of the school object is a ceramic bricks system, structural system of the sports hall is a reinforced concrete system. The roof of school object is warm flat roof and roof of sport hall is warm flat roof as well but mono-pitched type. The object has a U -shaped.
287

Contribution to digital microrobotics : modeling, design and fabrication of curved beams, U-shaped actuators and multistable microrobots / Contribution à la microrobotique numérique : modélisation, conception et fabrication de poutres bistables, d'actionneurs en U et de microrobots multistables

Hussein, Hussein 11 December 2015 (has links)
Un nombre de sujets concernant la microrobotique numérique ont été abordés dans le cadre de cette the` se. Une nouvelle génération du microrobot numérique ”DiMiBot” a e´ te´ proposé ce qui rend le DiMiBot plus précis, plus contrôlable et plus petit. La nouvelle structure est formée de deux modules multistables seulement, ce qui ajoute des fonctionnalités´ s importantes comme l’augmentation du nombre de positions avec une taille plus réduite et la capacité´ de réaliser des trajectoires complexes dans l’espace de travail. Le principe du nouveau module multistable combine les avantages des microactionneurs pas à pas en termes du principe et du concept numérique en termes de la répétabilité et la robustesse en boucle ouverte. Un mécanisme de positionnement précis, capable de compenser les incertitudes de fabrication a e´ te´ développé et utilise´ pour assurer un positionnement précis. En parallèle, des modèles analytiques ont e´ te´ développés pour les principaux composants dans le DiMiBot: poutres flambées préformées et actionneurs e´ électrothermiques en U. Des méthodes de conception ont été développées par la suite qui permettent de choisir les dimensions optimales garantissant les performances requises en respectant les spécifications et limites de design. Des prototypes de modules multistables, fabrique´ s dans la salle Blanche MIMENTO, ont montré´ un bon Fonctionnement dans les expériences. / A number of topics concerning digital microrobotics were addressed in this thesis. A new generation of the digital microrobot ”DiMiBot” was proposed with several advantages making the DiMiBot more accurate, more controllable and smaller. The new structure consists of only two multistable modules which adds some important features such as increasing the number of positions with smaller size and the ability to realize complex trajectories in the workspace. The principle of the new multistable module combines the advantages of the stepping microactuators in terms of the principle and of the digital concept in terms of the repeatability and robustness without feedback. The accuracy is ensured with an accurate positioning mechanism that compensate the fabrication tolerances. In parallel, analytical models was developed for the main components in the DiMiBot: preshaped curved beams and U-shaped electrothermal actuators. Subsequently, design methods were developed that allow choosing the optimal dimensions that ensure the desired outputs and respecting the design specifications and limitations. Multistable module prototypes, fabricated in the clean room MIMENTO, showed a proper functioning in the experiments.
288

Analýza napjatosti a porušení ve zkušebních tělesech používaných pro určování lomově-mechanických parametrů kvazikřehkých materiálů / Analysis of stress state and failure in test specimens used for determination of fracture-mechanical parameters of quasi-brittle materials

Holušová, Táňa January 2012 (has links)
The thesis is focused on a test on determination of the fracture-mechanical parameters of quasi-brittle materials, especially concrete. What is referred to as the wedge-splitting test is considered, for which a variety of shapes of notched specimen can be used. This work is exclusively focused on the cylinder-shaped specimen of diameter 150 mm and breadth of 100 mm. The test is performed virtually using Atena 2D FEM software. Progress of failure is observed during loading of the specimen for various notch lengths. The amount of energy released for the development the failure outside of the tested cross-sectional area (weakened by the notch) is quantified and the size of the fracture process zone is investigated. The described analysis is performed for several material sets witch differ in cohesive properties of the quasi-brittle material expressed via the so-called characteristic length. Suitable proportions of the test specimen are sought, in order to avoid the failure and thus also the energy dissipation outside of the specimen ligament area during the experimental tests, which shall lead to more accurate estimates of fracture-mechanical parameters of the tested material.
289

Effect of Configuration and Dimensions on the Thermo-Mechanical Performance of Spark Plasma Sintered Bismuth Telluride Annular Thermoelectric Generator (TEG) Modules

Abdelnabi, Ahmed January 2020 (has links)
Thermoelectric generators (TEG) are re-emerging technology that can be used to recover heat waste from commercial and industrial processes to generate electricity, enhancing fuel utilization and lowering greenhouse gas emissions. TEG modules are solid-state heat engines that produce no noise or vibration during operation. Notably, TEG modules are also able to operate at low-temperature differences, which makes them ideal for a wide range of heat waste recovery applications. Annular thermoelectric generator (ATEG) modules are optimal in applications where either the heat source or sink are round in shape. Bi2Te3 solution-based compounds are of significant interest in the application of thermoelectric materials (TE) used in low-temperature cooling and power generation applications. The main objective of the current work is to design a mechanically reliable ring-shaped ATEG module with a predictable performance using spark plasma sintered Bi2Te3 TE material for low temperature waste heat recovery applications. In terms of structure, this work is divided into two parts. The first part investigates how the use of a powder pre-treatment technique affects the mechanical and thermoelectric properties of P- and N-type Bi2Te3. In addition, part one also presents the measurements of these materials’ mechanical and thermoelectric properties, which serve as inputs for the finite element models used to design thermoelectric modules with parallel and perpendicular configurations vis-a-vis the sintering pressing direction. The second part evaluates the thermoelectric performance and thermal stresses of a ring-shaped ATEG couple that has been integrated between hot-side and cold-side heat exchangers. To this end, two configurations are compared with respect to their heat/electrical current flow paths: one that allows for radial flow (radial configuration), and one that allows for axial flow (axial configuration). The P- and N-type Bi2Te3 powder was treated using a mechanically agitated fluidized powder reduction facility that was built in-house. The characteristic uniaxial tensile strength of the P-type Bi0.4Sb1.6Te3 increased from 13.9 MPa to 26.3 MPa parallel to the sintering pressure, and from 16.3 MPa to 30.6 MPa perpendicular to the sintering pressure following oxide reduction using 5% H2 ˗ 95% Ar at 380 ℃ for 24 h. The figure of merit, ZT, increased from 0.35 to 0.80 and from 0.42 to 1.13 at room temperature (25 ℃) in the parallel and the perpendicular directions, respectively, after the surface oxide reduction treatment. On the other hand, the annealing effects of the oxide reduction pr-treatment of the N-type (Bi0.95 Sb0.05)2(Se0.05 Te0.95)3 using 5% H2 ˗ 95% Ar at 380 ℃ for 24 h were found to be responsible for the majority of the mechanical properties and ZT enhancement. Additionally, the characteristic uniaxial tensile strengths for this material increased from 30.4 to 34.1 MPa and from 30.8 to 38 MPa in the parallel and the perpendicular directions, respectively. The ZTmax (150 ℃) increased from 0.54 to 0.63 in both the parallel and perpendicular directions due to oxide reduction, while annealing led to an increase to 0.58 and 0.62 in the parallel and the perpendicular directions, respectively. An analytical model was constructed to compare the thermoelectric performance of the two configurations under three different hot-side thermal resistances, and a 3D coupled finite element ANSYS model was constructed to study and compare the thermal stresses of the two configurations at different dimensions. The two models were then used to create 2D maps in order to investigate the effects of ATEG couple configuration and dimensions, as well as the hot-side thermal resistance, with the goal of identifying the optimum design. The optimization of module geometry requires a trade-off between performance and mechanical reliability. The results of these investigations showed that increases in the temperature difference across the ATEG couple (ΔT) led to increases in both power and thermal stresses in both configurations. When both configurations were generating the same power at ΔT = 105 ℃, the thermal stresses in the radial configuration were as much as 67 MPa higher than those in the axial configuration due to the formation of additional tensile hoop stresses. The lowest thermal stress obtained for the axial couple configuration was 67.8 MPa, which was achieved when the couple had an outer diameter of 16 mm, an axial thickness of 1 mm, a ΔT of 14.8 ℃, and power generation of 10.4 mW per couple. The maximum thermal stress values were located at the corners of the interface between the solder and the TE rings due to the mismatched coefficient of thermal expansion. This thesis makes a novel contribution to the state-of-the-art literature in ring-shaped ATEG modules, as it details a well-characterised spark plasma sintered Bi2Te3 TE material and a methodology for designing a ring-shaped ATEG module with reliable, robust, and predictable thermoelectric and mechanical performance. The details of the contribution made by this work have been disseminated in the form of three journal publications, which have been integrated into this sandwich Ph.D. thesis. / Thesis / Doctor of Science (PhD)
290

Bronx - změna adresy (přestavba káznice) / Bronx - address substitution (reconstruction house of correction)

Kozel, Ondřej January 2009 (has links)
The subject of this graduation thesis is a conceptual architectural study of the former house of correction extension, annex and reconstruction and also a new ideological solution of adjacent areas and total building plan . The house is located in the Brno’s Bronx district. The reconstruction is focused on the use of alternative housing concepts with the general target at the whole city quarter reneration – address change.

Page generated in 0.0431 seconds