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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

Tribologinių procesų pjezoelektriniame kontakte tyrimas / Investigation of tribological properties of piezoelectric gear

Medikis, Mantas 28 May 2012 (has links)
Pjezoelektrinių savybių turinčios medžiagos mechaninį poveikį paverčia elektriniu impulsu (ir atvirkščiai). Įrengimai su šiomis medžiagomis yra kompaktiškesni, jautresni valdymui, jų didesnis naudingumo koeficientas, be to jos nereikalauja ypatingos priežiūros eksploataciniu laikotarpiu. Bet kaip ir visuose mechanizmuose taip ir pjezoelektrinėse porose vyksta dilimas, kuris ardo medžiagos paviršių ir sutrumpina įrenginio darbingumo laiką. Tyrimams atlikti suprojektavome ir pagaminome badymų stendą. Dilimo bandymus atlikome su keleto skirtingo kietumo plieninių medžiagų: HRB 85, HRB 14. Tyrimų metu nustatėme, kad iš negrūdinto plieno (HRB 45), pagamintas bandinys sukuria 30 % didesnę sukimo momento jėgą, nei iš anglinio plieno (HRB 85). Bet jo paviršius 3,5 karto greičiau nudyla, stipriai sumažėja bandinio greitis ir sukimo momentas. / The material with piezoelectric effect transforms mechanical motion into electric impulse (and vice versa). The devices are more compact, sensible to control, having higher coefficient of efficiency and it does not require any special attention for a period of exploitation than other devices. Usually in these kind of devices the process of wane causes the disruption to the surface of the material and piezoelectric mechanism in not an exception. In order to do the research, the stand for samples has been projected and made. Several different substances were used: no temper steel (HRB 85), carbonaceous steel (HRB 45). It was found out that the sample made of steel (HRB 45) creates 30 % bigger power of turning point than created with HRB 85. However, its surface frays 3,5 times faster, the speed of the sample and its turning point slow down.
12

Can you Handle this?

Silcock, Sabira January 2018 (has links)
Over the course of a day we meet countless materials and objects but rarely consider these surfaces of negotiation within the everyday environment. If we consider gestures as a language, then the actions we perform and the surfaces we encounter result in conversations with our surroundings. Where body meets details inside architecture, the commonplace ritual occurs. I will discuss the importance of touch in response to my finished work in Can you Handle this? but also during the making process.
13

Qualificando solos para revestimentos primários de rodovias : uma abordagem baseada nas mecânicas dos solos e dos pavimentos / Qualifying soils for road wearing courses : an approach based on mechanics of pavements and soil mechanics

Peraça, Vinícius January 2007 (has links)
Esta dissertação apresenta os resultados do estudo de dois solos saprolíticos de rochas vulcânicas, localizados em jazidas próximas às cidades de São Martinho da Serra e Silveira Martins (região central do RS), para aplicação como revestimento primário em estradas não pavimentadas da região ou como camada de pavimentos delgados. A análise dos materiais procura valer-se dos conhecimentos da Mecânica dos Pavimentos à luz dos conceitos da Mecânica dos Solos. Esta abordagem se justifica porque solos aplicados em revestimento primário estão sujeitos à ação do tráfego, porém seu comportamento será comandado pelos princípios da Mecânica dos Solos. O programa experimental incluiu ensaios de caracterização e classificação dos materiais, além de ensaios para a determinação do ISC e curva de compactação, difratometria de raios X, ensaios de cisalhamento direto na condição inundada, ensaios triaxiais de carga repetida para a obtenção dos módulos resilientes e das deformações permanentes e determinação das curvas de retenção de água dos materiais. Avalia-se a influência do teor de umidade e grau de compactação nos parâmetros de deformabilidade e resistência destes solos. Maior grau de compactação implica para estes materiais, crescimento dos parâmetros de resistência (c’ e f’), aumentando a resistência às tensões cisalhantes. O aumento do teor de umidade provoca a redução da sucção que, como conseqüência, provoca a diminuição das tensões efetivas e aumento das deformações resilientes e plásticas. Verifica-se que o solo de Silveira Martins é mais sensível à umidade se comparado ao solo de São Martinho da Serra, pois com apenas o acréscimo 2% de umidade em relação à ótima, o material sofre enormes deformações permanentes entrando em colapso. O material de São Martinho apresenta-se mais deformável e seu módulo resiliente decresce quando ocorre aumento no seu teor de umidade. Ao final, a análise mecanística apresentada permitiu avaliar algumas alternativas de uso destes materiais, seja como revestimento primário ou como camada estrutural de pavimentos, principalmente, com revestimentos delgados. Como era de se esperar, o grau de compactação exerceu grande influência no desempenho destes materiais em camadas de revestimento primário, explicitando a importância de compactá-los adequadamente. / This MSc thesis presents the results of a study of two saprolitic soils from volcanic rocks taken from sites near São Martinho da Serra and Silveira Martins towns (central area of RS State), for use as wearing course on unpaved roads of the region or as under layer of thinly surfaced road. The study uses knowledge from Pavement Mechanics with insights of Soil Mechanics concepts. The soils applied on wearing course are subjected to direct traffic action and their behavior will be influenced by Soil Mechanics principles. The experimental program included characterization tests, materials classification, ISC and compaction tests, X Rays difratogrammetry, direct shear tests on saturated and unsaturated conditions, repeated loading triaxial testing for resilient moduli determination, tests of permanent deformations and characteristic curves of the materials. The influence of the humidity and degree of compaction on the shear strength and deformability of the soils has been evaluated. In these materials a larger degree of compaction results in a growth of the shear strength parameters (c’and f’), increasing the resistance to shearing stress. The increase of the water content causes a reduction of the suction and, as consequence, a reduction of the effective stress and an increase of resilient and plastic deformations. It was verified that the Silveira Martins soil is more affected by water content variation than the São Martinho da Serra soil as an increase of only 2% of humidity above the optimum causes large deformations leading to collapse. The São Martinho da Serra soil is more deformable and its resilient modulus decreases when the water content is increased. The mechanistic analysis presented allowed the evaluation of some alternatives of use of these materials besides as structural layers of pavement with thin structural surfaces. As expected, the degree of compaction exerted great influence in the performance of these soils in wearing course, emphasizing the importance of adequate compaction.
14

Slitlager på broar : En kunskapssammanställning om slitlager på broar med fokus på slitbetong / Wearing Course on bridges : A knowledge of wearing course on bridges with focus on concrete

Embretsen, Erik, Häggström, Joel January 2018 (has links)
Denna rapport har kommit till efter en studie som genomförts för att försöka identifiera de viktigaste faktorerna som påverkar valet av slitlager på broar. Studien syftade även till att försöka bringa klarhet över vilka grunder som slitlager tidigare har valts på och bör väljas på i framtiden. Resultatet av studien är att slitlager riskeras att baseras på oklara grunder utan en tydlig motivering och otydliga riktlinjer. Det är ofta som personliga åsikter har ett stort inflytande i valet av slitlager. Ekonomi, typ av entreprenad eller estetik är andra avgörande faktorer vid val av slitlager. Studien har genomförts utifrån djupgående intervjuer med sakkunniga personer. / This report is the result of a study conducted to try to identify the most important factors affecting the choice of surface course on bridges. The study also aimed to clarify the reasons for which surface course were previously chosen and should be chosen in the future. The result of the study is that the surface course are likely to be chosen on unclear grounds without a clear motivation and unclear guidelines. It is often that private opinions have a big influence on the choice of the surface course. Economics, type of contract or aesthetics are other crucial factors in choosing of the surface course. The study has been conducted using in-depth interviews with people having knowledge in the field.
15

Qualificando solos para revestimentos primários de rodovias : uma abordagem baseada nas mecânicas dos solos e dos pavimentos / Qualifying soils for road wearing courses : an approach based on mechanics of pavements and soil mechanics

Peraça, Vinícius January 2007 (has links)
Esta dissertação apresenta os resultados do estudo de dois solos saprolíticos de rochas vulcânicas, localizados em jazidas próximas às cidades de São Martinho da Serra e Silveira Martins (região central do RS), para aplicação como revestimento primário em estradas não pavimentadas da região ou como camada de pavimentos delgados. A análise dos materiais procura valer-se dos conhecimentos da Mecânica dos Pavimentos à luz dos conceitos da Mecânica dos Solos. Esta abordagem se justifica porque solos aplicados em revestimento primário estão sujeitos à ação do tráfego, porém seu comportamento será comandado pelos princípios da Mecânica dos Solos. O programa experimental incluiu ensaios de caracterização e classificação dos materiais, além de ensaios para a determinação do ISC e curva de compactação, difratometria de raios X, ensaios de cisalhamento direto na condição inundada, ensaios triaxiais de carga repetida para a obtenção dos módulos resilientes e das deformações permanentes e determinação das curvas de retenção de água dos materiais. Avalia-se a influência do teor de umidade e grau de compactação nos parâmetros de deformabilidade e resistência destes solos. Maior grau de compactação implica para estes materiais, crescimento dos parâmetros de resistência (c’ e f’), aumentando a resistência às tensões cisalhantes. O aumento do teor de umidade provoca a redução da sucção que, como conseqüência, provoca a diminuição das tensões efetivas e aumento das deformações resilientes e plásticas. Verifica-se que o solo de Silveira Martins é mais sensível à umidade se comparado ao solo de São Martinho da Serra, pois com apenas o acréscimo 2% de umidade em relação à ótima, o material sofre enormes deformações permanentes entrando em colapso. O material de São Martinho apresenta-se mais deformável e seu módulo resiliente decresce quando ocorre aumento no seu teor de umidade. Ao final, a análise mecanística apresentada permitiu avaliar algumas alternativas de uso destes materiais, seja como revestimento primário ou como camada estrutural de pavimentos, principalmente, com revestimentos delgados. Como era de se esperar, o grau de compactação exerceu grande influência no desempenho destes materiais em camadas de revestimento primário, explicitando a importância de compactá-los adequadamente. / This MSc thesis presents the results of a study of two saprolitic soils from volcanic rocks taken from sites near São Martinho da Serra and Silveira Martins towns (central area of RS State), for use as wearing course on unpaved roads of the region or as under layer of thinly surfaced road. The study uses knowledge from Pavement Mechanics with insights of Soil Mechanics concepts. The soils applied on wearing course are subjected to direct traffic action and their behavior will be influenced by Soil Mechanics principles. The experimental program included characterization tests, materials classification, ISC and compaction tests, X Rays difratogrammetry, direct shear tests on saturated and unsaturated conditions, repeated loading triaxial testing for resilient moduli determination, tests of permanent deformations and characteristic curves of the materials. The influence of the humidity and degree of compaction on the shear strength and deformability of the soils has been evaluated. In these materials a larger degree of compaction results in a growth of the shear strength parameters (c’and f’), increasing the resistance to shearing stress. The increase of the water content causes a reduction of the suction and, as consequence, a reduction of the effective stress and an increase of resilient and plastic deformations. It was verified that the Silveira Martins soil is more affected by water content variation than the São Martinho da Serra soil as an increase of only 2% of humidity above the optimum causes large deformations leading to collapse. The São Martinho da Serra soil is more deformable and its resilient modulus decreases when the water content is increased. The mechanistic analysis presented allowed the evaluation of some alternatives of use of these materials besides as structural layers of pavement with thin structural surfaces. As expected, the degree of compaction exerted great influence in the performance of these soils in wearing course, emphasizing the importance of adequate compaction.
16

Qualificando solos para revestimentos primários de rodovias : uma abordagem baseada nas mecânicas dos solos e dos pavimentos / Qualifying soils for road wearing courses : an approach based on mechanics of pavements and soil mechanics

Peraça, Vinícius January 2007 (has links)
Esta dissertação apresenta os resultados do estudo de dois solos saprolíticos de rochas vulcânicas, localizados em jazidas próximas às cidades de São Martinho da Serra e Silveira Martins (região central do RS), para aplicação como revestimento primário em estradas não pavimentadas da região ou como camada de pavimentos delgados. A análise dos materiais procura valer-se dos conhecimentos da Mecânica dos Pavimentos à luz dos conceitos da Mecânica dos Solos. Esta abordagem se justifica porque solos aplicados em revestimento primário estão sujeitos à ação do tráfego, porém seu comportamento será comandado pelos princípios da Mecânica dos Solos. O programa experimental incluiu ensaios de caracterização e classificação dos materiais, além de ensaios para a determinação do ISC e curva de compactação, difratometria de raios X, ensaios de cisalhamento direto na condição inundada, ensaios triaxiais de carga repetida para a obtenção dos módulos resilientes e das deformações permanentes e determinação das curvas de retenção de água dos materiais. Avalia-se a influência do teor de umidade e grau de compactação nos parâmetros de deformabilidade e resistência destes solos. Maior grau de compactação implica para estes materiais, crescimento dos parâmetros de resistência (c’ e f’), aumentando a resistência às tensões cisalhantes. O aumento do teor de umidade provoca a redução da sucção que, como conseqüência, provoca a diminuição das tensões efetivas e aumento das deformações resilientes e plásticas. Verifica-se que o solo de Silveira Martins é mais sensível à umidade se comparado ao solo de São Martinho da Serra, pois com apenas o acréscimo 2% de umidade em relação à ótima, o material sofre enormes deformações permanentes entrando em colapso. O material de São Martinho apresenta-se mais deformável e seu módulo resiliente decresce quando ocorre aumento no seu teor de umidade. Ao final, a análise mecanística apresentada permitiu avaliar algumas alternativas de uso destes materiais, seja como revestimento primário ou como camada estrutural de pavimentos, principalmente, com revestimentos delgados. Como era de se esperar, o grau de compactação exerceu grande influência no desempenho destes materiais em camadas de revestimento primário, explicitando a importância de compactá-los adequadamente. / This MSc thesis presents the results of a study of two saprolitic soils from volcanic rocks taken from sites near São Martinho da Serra and Silveira Martins towns (central area of RS State), for use as wearing course on unpaved roads of the region or as under layer of thinly surfaced road. The study uses knowledge from Pavement Mechanics with insights of Soil Mechanics concepts. The soils applied on wearing course are subjected to direct traffic action and their behavior will be influenced by Soil Mechanics principles. The experimental program included characterization tests, materials classification, ISC and compaction tests, X Rays difratogrammetry, direct shear tests on saturated and unsaturated conditions, repeated loading triaxial testing for resilient moduli determination, tests of permanent deformations and characteristic curves of the materials. The influence of the humidity and degree of compaction on the shear strength and deformability of the soils has been evaluated. In these materials a larger degree of compaction results in a growth of the shear strength parameters (c’and f’), increasing the resistance to shearing stress. The increase of the water content causes a reduction of the suction and, as consequence, a reduction of the effective stress and an increase of resilient and plastic deformations. It was verified that the Silveira Martins soil is more affected by water content variation than the São Martinho da Serra soil as an increase of only 2% of humidity above the optimum causes large deformations leading to collapse. The São Martinho da Serra soil is more deformable and its resilient modulus decreases when the water content is increased. The mechanistic analysis presented allowed the evaluation of some alternatives of use of these materials besides as structural layers of pavement with thin structural surfaces. As expected, the degree of compaction exerted great influence in the performance of these soils in wearing course, emphasizing the importance of adequate compaction.
17

Importancia de la determinación de un micropavimento en frío como capa de rodadura de alta performance para el proyecto Conococha – Recuay

Rujel Atoche, Carlos Enrique, Solórzano Durand, Karol Jackeline January 2015 (has links)
El presente proyecto de tesis es una investigación cualitativa de diseño experimental-exploratoria donde el objeto es mostrar la Importancia de la Determinación de un Micropavimento en frío como capa de rodadura asfáltica de Alta Performance desestimando otras soluciones técnicas para Conservación Vial de Carreteras desarrolladas en el Perú, para un proyecto que presenta factores complejos tanto en clima, geografía y tráfico en el Departamento de Ancash, Proyecto Conococha – Recuay. El Micropavimento en frío es una mezcla asfáltica de alto performance, se caracteriza por su durabilidad en el tiempo “vida útil” y en su comportamiento ante climas severos característicos de nuestro país, geografía abrupta y tráfico intenso, está compuesta por agregados 100% triturados, emulsión asfáltica modificada con polímeros, filler mineral, agua y aditivos. Se empleó el uso de laboratorios especializados para determinar la compatibilidad de materiales, diseño de la mezcla y aplicación en el proyecto, así mismo se verificó el control de calidad durante la aplicación del micropavimento para dar factibilidad a la solución planteada. Se concluye que al aplicar un micropavimento en frio de 10mm. de espesor bajo las condiciones climáticas, geográficas y tráfico es mas rentable a lo largo de la vida útil del pavimento, presenta un excelente confort, su impacto es positivo al medio ambiente, de alto rendimiento de colocación y rápida apertura al tráfico; por estos motivos se determina que es la solución técnica mas efectiva para el Proyecto Conococha – Recuay. This thesis project is a qualitative exploratory-experimental research design where the object is to show the importance of determining a cold microsurfacing as asphalt wearing course of High Performance dismissing other technical solutions developed Road Maintenance in Peru for a project that presents complex factors both in climate, geography and traffic in the Department of Ancash, Conococha – Recuay Project. The cold microsurfacing is an asphalt mixture of high performance, it is characterized by its durability over time "life" and its behavior in typical severe weather of our country, rugged geography and intense traffic, it is composed of 100% crushed aggregates, polymer-modified emulsified asphalt, mineral filler, water and additives. The use of specialized laboratories was used to determine the compatibility of materials, mix design and implementation in the project, also the quality control was verified during the application of microsurfacing to give feasibility to the proposed solution. It concludes that by applying a cold microsurfacing, 10mm. thick under the climatic, geographic and traffic is more cost effective over the pavement’s life, features an excellent comfort, its impact is positive for the environment, high-performance positioning and quick opening to traffic; for these reasons it is determined to be the most effective technical solution to the Conococha - Recuay Project.
18

The Clothes I Live In

Schultz, Maike January 2017 (has links)
This work explores the relation between the body and garments by illustrating the cycle of dressing, wearing and undressing in woven images. Based on experimental methods, such as scanning and photographing, images of garments are generated capturing garment details, surface qualities, movement, folds and volume. These demonstrate the constantly changing relation between the body and garments within the cycle of dressing, wearing and undressing. In translating the photographs and scans of the garments into weaves, a shading technique for jacquardweaving is applied that enables a translation of an image of a 3D-garment into a flat weave keeping the 3D qualities present in the picture. Through a gradation of satin weaves, different hues are created in order to define shadows and other surface qualities.  The changing relation between the body and garments is interpreted in different ways including the body’s presence as well as its absence which results in immediate material responses of the garments and demonstrates the various appearances of the body within this relation. This work results in a variety of woven images pointing out the different stages within the cycle of dressing, wearing and undressing. By using the image as a tool, its pictorial value of capturing moments of change and succession is emphasized. With this work, a new perception of bodily shapes in textiles is provided. Instead of imitating the body’s presence in garments through 3D – forms, alternative ways are shown in how to achieve a corporal illusion in flat weaving-constructions.
19

Repetition Recurrence Return

Lundstedt, Lotta January 2021 (has links)
Repetition is part of our everyday lives: it is all around us, in patterns, art, and habits like having a cup of tea or getting dressed each morning. Repetition, recurrence, and return are also fundamental in nature – there are shifts in the seasons and regular, rhythmic elements, such as the weather, that occur over and over again. In order to repeat you have to remember what you did last time, and memories are intimate and can be associated with personal relationships with objects or clothes; they are not written down but preserved in memories of lived events, which over time become mythologised. In fashion, repetition is linked to imitation: we see how our friends, partners, and people on social media are dressed, and we want to look the same. This has created endless loops of trends, wherein we constantly strive for the new. When we consciously repeat or return there is the possibility to pay attention to our behaviour in relation to consumption and how we spend our time, wear our clothes, and relate to the natural world. This thesis has taken me on a journey which started with the world of repetition, where memories, habits, and nature are visited and revisited. The journey progressed through five destinations/projects at a slow pace: at each, textile art, craft and fashion were explored. Repetition, recurrence, and return were used as methods to explore time and timing in textile making with a focus on the tension and duality between the making and the made.
20

Tenkovrstvé emulzní úpravy / Slurry surfacing

Koudelka, Tomáš January 2014 (has links)
This thesis is focused on microsurfacing technology. The theoretical part describes modern trends especially in the field of coloured surfaces and special system Flexiplast®. The practical part presents the results of conducted tests, particularly tests of breaking time, cohesion, determination of wearing and determination of friction after polishing. The key advantage is that it specifies which aggregates, which were taken from quarries through the Czech Republic, are convenient for this specialized technology. It was verified that RAP material suits use in microsurfacing. Furthermore, colour mixtures are viable for practical application which was confirmed by tests in the laboratory and trial lying as well. Special use of technology in the system Etanpalst and pictures which show field work are presented.

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