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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.
471

Textilverstärkte Zugmittel für die Antriebs- und Fördertechnik mit formschlüssiger Krafteinleitung

Hübler, Jörg 19 June 2013 (has links)
Die Arbeit befasst sich mit einem neuen textilverstärkten Zugmittel mit formschlüssiger Krafteinleitung. Im Grundlagenteil werden Aufbau, Eigenschaften und Dimensionierungsgrundlagen von Rollenketten und Zahnriemenantrieben erörtert, sowie textile und elastomere Werkstoffe betrachtet. Aus den Betrachtungen zum Stand der Technik, der Maschenware mit hochfesten Filamentgarnen und deren polymeren Beschichtungen wird der Entwicklungsansatz abgeleitet. Mit Hilfe eines Spezialkettenwirkverfahrens werden die textilen Zugträger als Recht/Links-Maschenware hergestellt. Das besondere daran ist die teilungsgenaue Einbindung der Bolzen in die Maschenstruktur bei der Fertigung. Eine anschließende elastomere Beschichtung verbessert die mechanischen Eigenschaften erheblich und fixiert die Bolzen axial. Dabei werden reaktive Polyurethane im Gießverfahren und thermoplastische Elastomere im Spritzgießverfahren eingesetzt. Drei ausgewählte textile Bindungen mit verschiedenen Beschichtungen wurden statisch und dynamisch, anhand von Proben und endlos verbundenen Zugmitteln, ausführlich untersucht. Die daraus abgeleiteten Bauteil-Wöhlerlinien und Leistungsdiagramme bilden die Grundlage zur Auslegung der textilverstärkten Zugmittel für Anwendungen im Maschinenbau. / The dissertation deals with a new textile reinforced with form-closed force application. The basis of structure, properties and sizing basics of roller chain drives and belt drives are discussed and considered textile and elastomeric materials. From consideration of the prior art, the knitted fabric with high tenacity filament of polymeric coatings and their development approach is derived. Using a special knitting process, the textile chain tension members are produced as a right / left-knit fabric. The special thing about it is the exact distribution of involvement of the pins in the mesh structure during manufacturing. Subsequent elastomeric coating significantly improves the mechanical properties and fixes the bolt axially. These reactive polyurethanes by casting and thermoplastic elastomers are used in injection molding. Three selected textile bonds with different coatings were statically and dynamically examine in detail the basis of samples and associated endless traction means. The derived component S/N curves and performance charts are the basis for the design of textile-reinforced tension means for applications in mechanical engineering.
472

Den optimala kombinationen : En produktutvecklingsstudie som undersöker fiberkombinationen merinoull och lyocell, konstruerad till en lager-2 produkt / The optimal combination : A product development study investigating the fiber combination of merino wool and lyocell, designated for a layer-2 product

Ekorre, Elina, Järlebratt, Almida January 2023 (has links)
Syftet med studien är att undersöka hur TencelTM och merinoull bäst kombineras i en stickad frottéstruktur ämnad för en lager-2 produkt. Den stickade strukturen har funktionella krav gällande god fukttransport, nötningsbeständighet och antipilling. Funktionskraven kommer att prövas med standardiserade tester. Ytterligare kommer studien undersöka om hållbarheten för lager-2-tyg skulle kunna förbättras. En design research method används för att skapa tre frottéstickade trikåstrukturer, alla med olika kombinationer av lyocell och merinoull. Resultaten visade att alla strukturer hade relativt goda förmåga att transportera fukt, dock stod S-M-T ut som bäst, tätt följt av T-M. Bra nötningsbeständighet utmärktes i M-T och T-M, medan S-M-T presterade sämst. Slutligen visade ett pillingstest ett jämnt resultat mellan alla stickade strukturer, T-M fick dock ett något högre snitt än de andra två. Resultaten i relation till hållbarhet visade att ingen av de stickade strukturerna var ensamt signifikant bättre än de andra. Däremot ger studien ett förslag för framtida forskning när det gäller att samspunna garnet placeras på ena sidan, medan merinoull på den andra. / This study aims to investigate how TencelTM and merino wool are best combined in a knitted terry structure modified for layer-2. The knitted structure has functional requirements, which are in regards to good moisture transport (wicking) capacity, abrasion resistances and anti-pilling. The functional requirements will be tested and with the help of the result the study will further investigate if the sustainability of layer-2 fabric could improve. A design research method is applied to create three terry knitted fabric structures, all with different combinations of lyocell and merino wool. The three fabric structures are then assets for the functional requirements through ISO Standards and AATCC tests. The results showed that all structures had relatively good wicking properties, however S-M-T stood out as the best, closely followed by T-M. Good abrasion resistance was noticeable mostly in M-T and T-M, whereas S-M-T performed worst. Lastly, a pilling test showed an even result between all knitted structures, T-M received however a slightly higher average than the other two. The results in relation to sustainability showed that none of the knitted structures were significantly better than the others alone. However, a suggestion for future research is made in regards to the co-spun yarn being placed on one side, while merino wool on the other.
473

Study on the effects of matrix properties on the mechanical properties of carbon fiber reinforced plastic composites / 炭素繊維強化複合材料の機械特性に及ぼす母材特性の影響に関する研究 / タンソ センイ キョウカ フクゴウ ザイリョウ ノ キカイ トクセイ ニ オヨボス ボザイ トクセイ ノ エイキョウ ニカンスル ケンキュウ

邵 永正, Yongzheng Shao 22 March 2015 (has links)
It was found that a significant improvement of mechanical properties of CFRPs can be achieved by the adjustment of the matrix properties such as toughness and CF/matrix adhesion via the chemical modification, as well as the physical modification by a small amount of cheap and environment-friendly nano fibers. Based on investigation of fracture mechanisms at macro/micro scale, the effects of matrix properties and nano fiber on the mechanical properties of CFRP have been discussed. Subsequently, the relationship has been characterized by a numerical model to show how to modulate the parameters of the matrix properties to achieve excellent fatigue properties of CFRP. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University
474

Smart Contract Maturity Model

van Raalte, Jordy Jordanus Cornelius January 2023 (has links)
A smart contract is a recently emerging technology which enables agreement to be automatable by computers and enforceable by legal enforcement or tamper-proof execution of code. A majority of smart contracts are run on the blockchain which enables smart contract transactions without a central authority. Smart contract implementation contains several challenges which makes implementation more difficult. The problem is that organisations struggle to implement smart contracts due to the absence of documentation, standardisation, and guidelines making it difficult to know how a smart contract should be implemented. Additionally, it is unclear what capabilities and tools are required for smart contract implementation. Therefore, it is challenging for organisations to assess their own competence of smart contract implementation. This thesis aims to develop a Smart Contract Maturity Model (SCMM). The purpose of the model is to clarify the functionalities and capabilities required to implement a smart contract while also offering organisations the ability to assess the smart contract implementation competency. This improves the adoption of smart contracts. Through the help of the design science framework, the SCMM emerged from the thesis. Applying design science included explicating the problem, defining requirements, designing and developing the artefact, demonstrating and evaluating the artefact. A literature survey was used to explicate the problem and to define requirements for the maturity model. Furthermore, a case study including interviews were used to refine the requirements and to demonstrate and evaluate the SCMM. The SCMM includes maturity levels, generic goals and practices, specific goals, key processing areas and practices, tools, glossaries and smart contract examples. Inspired by the Capability Maturity model Model Integration for Development (CMMI-DEV), the maturity levels of the SCMM consisted of initial, foundation, managed, defined, quantitatively managed and optimising. The identified key processing areas were stakeholder capabilities, resources and tools, platform, contract implementation, standards, laws and terminology and security. Although there were several limitations, the SCMM contributed to the field of smart contracts by closing the gap of previous research and improving the adoption of smart contracts.
475

dis.PLAY - Center for the Art of Moving Images. A Film Center for Washington, D.C.

Torres-Barreto, Jose Antonio 10 March 2006 (has links)
This thesis explores how a displayed image and architecture interact together. This manifesto is analogically explored using parts of the human body such as the eyeballs as a structural analysis for the buildings with a projection of the cornea, the pupil, the retina, the optic nerves and the brain. This analysis follows a sequential order of capturing light, transcribing light into image, and displaying such image onto a screen. Both, the image and architecture are created parallel to each other respectively when conceiving an architectural idea in order to develop the idea into a building and then perceiving the architecture from such building. These steps are a cinematic approach using a video camera to record an experience of movement through the journey of a metro ride. This video is one of the tools used to edit an urban tissue of downtown Washington, D.C. The project becomes a Center for the Art of Moving Images exposing vectors of movements through its architecture. The building is manifested in a three-dimensional design where the site provides a sunken plaza 60 ft below street level perceived as a new floor in the city. The underground metro station transitions to the street surface through the use of this plaza in a very harmonious way. The result is a visual depth parallel to the perspectives perceived in movies where you see beyond the surface of the screen and in this case, beyond the surface of the city. / Master of Architecture
476

La Brittle Ware en Syrie: étude d'une production, de l'époque romaine à l'époque omeyyade

Vokaer, Agnès 25 February 2005 (has links)
Cette thèse de doctorat constitue une première étude de synthèse de la céramique de cuisine (Brittle Ware), de l’époque romaine à l’époque omeyyade en Syrie. Cette recherche repose sur une approche méthodologique combinant un classement typologique des formes et un classement par groupes de pâtes. Le corpus étudié provient de plusieurs sites archéologiques de Syrie du nord, dont la céramique de cuisine est encore inédite et pour laquelle on ignore les centres de production (Apamée, Andarin, Alep et Dibsi Faraj). Ce travail a entrepris d’identifier le nombre d’ateliers et leur localisation, leur profil de production et leur aire de diffusion. Les objectifs sont de caractériser la production de Brittle Ware depuis la manufacture jusqu’aux contextes de consommation, <p>L’étude chrono-typologique a permis de définir le répertoire de la Brittle Ware et de situer sa production entre l’époque hellénistique (3e av. J.-C.) et l’époque mamelouke (13e s. apr. J.-C.). Aux époques romaine, byzantine et omeyyade, un même assemblage formel, constituant un service de cuisine se diffuse dans toute la province antique de Syrie. Ce service de cuisine est constitué d’un pot à cuire haut et fermé qui devait servir aux liquides et aux bouillies, d’une casserole ouverte pour les plats mijotés et d’une cruche. <p>L’analyse minéralogique et chimique des pâtes a identifié cinq groupes de pâte, correspondant à cinq zones de production. L’origine des matières premières exploitées a pu être localisée dans le nord-ouest de la Syrie, à proximité de l’Euphrate et dans le sud-ouest de la Syrie. L’étude des pâtes et des formes de Brittle Ware dans leur contexte géographique et chronologique a de surcroît montré que ces cinq sources d’argile correspondent à cinq centres de production. Les profils de ces centres de production ont pu être définis :leur durée d’activité et l’aire géographique de leur diffusion varie pour chacun d’entre eux. Quatre sont des ateliers syriens alors que le dernier semble être localisé plus au sud. Deux centres de production ont une diffusion supra-régionale (couvrant plusieurs zones géographiques). L’un diffuse ses produits de Syrie occidentale jusqu’à l’Euphrate et l’autre, moins attesté à l’est, constitue l’unique fournisseur de la ville d’Apamée. Les trois autres centres ont une distribution régionale. La plupart de ces ateliers partagent le même service de cuisine, témoignant de la transmission d’un savoir-faire technique et formel sur plusieurs générations.<p>Alors qu’à l’époque hellénistique, on note sur quelques sites la présence d’une vaisselle culinaire différente, qui s’apparente aux traditions de l’Âge du Fer et de l’Âge du Bronze syrien, l’étude de la distribution de la Brittle Ware en Syrie révèle que celle-ci représente l’unique céramique de cuisine utilisée aux époques romaines et byzantines. En outre, les formes typiques de la Brittle Ware ne sont pas attestées en dehors des limites de la province antique de Syrie :en Cilicie, en Palestine ou à Chypre. Les céramiques culinaires des régions limitrophes de la Syrie constituent d’autres faciès régionaux qui partagent néanmoins des traditions formelles et techniques avec les productions de Brittle Ware. Ces autres faciès sont caractérisés par leurs répertoires typologiques spécifiques, par ailleurs inconnus en Syrie.<p>Les cartes de distribution de la Brittle Ware et la comparaison avec les productions des régions limitrophes montrent par conséquent que la production de Brittle Ware représente un commerce à échelle supra-régionale, tourné essentiellement vers l’intérieur de la Syrie. Le fait que ce commerce ne dépasse pas les limites de la province, loin d’être un facteur négatif, indique que la production de Brittle Ware est suffisamment prospère pour défier la concurrence. <p>L’étude des contextes de production de la Brittle Ware montre que cette catégorie de vaisselle, bien qu’utilitaire était l’objet d’une production de masse, diffusée à l’échelle d’une province et provenant sans doute de grands centres de production spécialisés. Cette recherche couvrant trois périodes historiques contribue à notre connaissance de l’économie syrienne, car elle illustre la pérennité des centres de production et de certains réseaux d’échange, depuis l’époque romaine jusqu’à la fin de l’époque omeyyade.<p> / Doctorat en philosophie et lettres, Orientation histoire de l'art et archéologie / info:eu-repo/semantics/nonPublished
477

Quand l'aéroport devient ville : géographie d'une infrastructure paradoxale / When an airport becomes a city : geography of a paradoxical infrastructure

Drevet-Démettre, Lucie-Emmanuelle 11 September 2015 (has links)
L’aéroport est un objet géographique protéiforme, caractérisé par son « obsolescence accélérée » (BANHAM, 1962). Depuis les années 1990, son ultime mutation s’articule autour d’un processus de diversification fonctionnelle engendré par l’injection d’activités nouvelles, parfois éloignées du transport aérien, dans l’objectif d’accroître les profits et la rentabilité de l’infrastructure dans un contexte de privatisation généralisée. Cette évolution concerne les plus grands hubs mondiaux, notamment Paris-CDG, quatrième aéroport du monde selon le trafic passagers international. Cette tendance, qui a donné naissance au concept opérationnel d’airport city, tel qu’il est désigné par les observateurs et opérateurs anglo-saxons, attise doublement la curiosité géographique. En premier lieu, parce qu’elle interroge la fonction première de l’infrastructure de transport qu’est l’aéroport, qui devient alors un objet spatial non identifié qu’il convient de redéfinir. En second lieu, parce que cette désignation d’airport city, traduite par les opérateurs francophones par ville aéroportuaire, interroge la ville et surtout ce qui fait la ville dans ses dimensions matérielle et idéelle, c’est-à-dire l’urbanité et la citadinité. Suffit-il d’injecter des fonctions urbaines dans un espace pour en faire de la ville ? La ville aéroportuaire n’est-elle qu’une ville fonctionnelle ? En s’efforçant d’évaluer la pertinence géographique de la notion d’airport city, cette thèse impose de faire de l’urbanité et de la citadinité des concepts opératoires afin de les confronter au terrain aéroportuaire. Elle s’efforce également de replacer l’aéroport au centre de l’étude géographique en proposant un ajustement de l’échelle d’observation à l’ensemble de la zone aéroportuaire, évitant ainsi la synecdoque particularisante réduisant l’aéroport au terminal. Dans l’évaluation de la citadinité, elle a également pour objectif de saisir les spatialités de l’ensemble de la société aéroportuaire (passagers, employés, accompagnants, SDF, etc.). / Airports are protean geographical objects characterized by their « accelerated obsolescence » (BANHAM, 1962). Since the 1990s, their final transformation has been structured around a process of functional diversification engendered by new activities, which are sometimes very different from air transport, in order to increase the infrastructures’ profits and profitability in a context of widespread privatization. The world’s largest hub airports are concerned by this evolution, especially the Paris-Charles-de-Gaulle airport, the world’s fourth busiest airport by international passenger traffic. This trend, which has given birth to the operational concept of airport city, as the Anglo-Saxon operators and observers call it, stirs up the geographical curiosity in two ways. Firstly, it questions the primary function of airports, which become unidentified spatial objects that need to be redefined. Secondly, the concept of airport city questions the city itself. Indeed, what makes a city a city on a material (urbanity) and conceptual (“citadinity”) level? Can a space with urban functions be considered as a city? Is the airport city only a functional city? By assessing the geographical relevance of the concept of airport city, this thesis aims at making the concepts of urbanity and “citadinity” operational concepts, so as to compare them with the airport ground. By adjusting the observation scale to the whole airport area, it also replaces the airport at the centre of the geographical study. Thus, the airport is not simply viewed as a terminal. Finally, this thesis aims at understanding the whole airport society’s spatiality (passengers, employees, accompanying people, homeless people…) by assessing the concept of “citadinity".
478

Empleo de textiles en aplicaciones de absorción sonora

Segura Alcaraz, María del Pilar 21 January 2021 (has links)
[ES] Esta memoria de tesis presenta una contribución al estudio de los materiales textiles en el campo de la absorción sonora. En concreto, se ha trabajado con la asociación de una capa absorbente fibrosa constituida por una estructura laminar no tejida cuya composición es poliéster y una capa resistiva a base de tejido de calada también compuesta de poliéster. El objetivo de este trabajo consiste en evaluar las variaciones que provocan los cambios en distintos parámetros de construcción de la capa resistiva, sobre el comportamiento del conjunto ante el sonido. Para abordar el problema se emplean distintos tejidos de calada, tales como telas simples, múltiples, acolchadas y rizo, con diferentes parámetros de construcción. Se mide el coeficiente de absorción de sonido al aplicarlas a diferentes espesores de estructura no tejida de poliéster, empleando el tubo de ondas estacionarias. Tras analizar los resultados obtenidos, se observan diferencias en los coeficientes de absorción de sonido alcanzados, las cuales se explican atendiendo al espesor del no tejido, pero también se observa la influencia de las características constructivas de los tejidos empleados. Finalmente, se emplea el diseño de experimentos para obtener la combinación óptima de parámetros que proporciona el mayor coeficiente de absorción de sonido para un tipo de tejido dado en todas las frecuencias estudiadas. Se concluye que, la modificación en la absorción de sonido de una estructura no tejida al aplicar una capa resistiva de tejido de calada, es lo suficientemente significativa como para ser tenida en cuenta a la hora de diseñar productos textiles para acondicionamiento acústico y que el diseño de experimentos constituye una herramienta de gran utilidad a este fin. / [CAT] Aquesta memòria de tesi presenta una contribució a l'estudi dels materials tèxtils en el camp de l'absorció sonora. En concret, s'hi ha treballat amb l'associació d'una capa absorbent fibrosa constituïda per un no teixit de polièster i una capa resistiva a base de teixit de calada de composició polièster. L'objectiu d'aquest treball consisteix a avaluar les variacions que provoquen els canvis en diferents paràmetres de construcció de la capa resistiva, sobre el comportament del conjunt davant el so. Per a abordar el problema s'empren diferents teixits de calada, com ara teles simples, múltiples, encoixinats i ris, amb diferents paràmetres de construcció. Es mesura el coeficient d'absorció en aplicarles a diferents grossàries de no teixit de polièster, emprant el tub d'ones estacionàries. S'observen diferències en els coeficients d'absorció de so obtinguts, les quals s'expliquen atenent la grossària del no teixit, però també a les característiques constructives dels teixits emprats. Finalment, s'empra el disseny d'experiments per a obtenir la combinació òptima de paràmetres que proporciona el major coeficient d'absorció de so per a un tipus de teixit donat en totes les freqüències estudiades. Es conclou que la modificació en l'absorció de so d'un no teixit en aplicar una capa resistiva de teixit de calada és prou significativa per a ser tinguda en compte a l'hora de dissenyar productes tèxtils per a condicionament acústic i que el disseny d'experiments constitueix una eina de gran utilitat a aquest efecte. / [EN] This thesis report presents a contribution to the study of textile materials in the field of sound absorption. Specifically, we have worked with the association of a fibrous absorbent layer consisting of a polyester nonwoven and a resistive layer based on openwork fabric. The objective of this work is to evaluate the variations that cause the changes in different construction parameters of the resistive layer, on the behaviour of the whole before the sound. To address the problem, different openwork fabrics are used, such as single, multiple, quilted and curl fabrics, with different construction parameters. The absorption coefficient is measured when applied to different thicknesses of polyester nonwoven, using the standing wave tube. Differences are observed in the sound absorption coefficients obtained, which are explained according to the thickness of the nonwoven, but also to the constructive characteristics of the fabrics used. Finally, the design of experiments is used to obtain the optimal combination of parameters that provides the highest sound absorption coefficient for a given type of tissue at all frequencies studied. It is concluded that the modification in the sound absorption of a nonwoven when applying a resistive layer of openwork fabric is significant enough to be taken into account when designing textual products for acoustic conditioning and that the design of experiments constitutes a very useful tool for this purpose. / Al departamento de Ingeniería Textil y Papelera y a la unidad docente de Alcoy del departamento de Mecánica de los Medios Continuos y Teoría de Estructuras, por facilitarme los medios necesarios para realizar todas las actividades que han sido necesarias. A Jaime Ramis Soriano, por recibirme en el laboratorio de Grupo de Acústica Aplicada del IUFACyT de la Universidad de Alicante. / Segura Alcaraz, MDP. (2020). Empleo de textiles en aplicaciones de absorción sonora [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159786 / TESIS
479

Validation and application of advanced soil constitutive models in numerical modelling of soil and soil-structure interaction under seismic loading

Kowalczyk, Piotr Jozef 23 September 2020 (has links)
This thesis presents validation and application of advanced soil constitutive models in cases of seismic loading conditions. Firstly, results of three advanced soil constitutive models are compared with examples of shear stack experimental data for free field response in dry sand for shear and compression wave propagation. Higher harmonic generation in acceleration records, observed in experimental works, is shown to be possibly the result of soil nonlinearity and fast elastic unloading waves. This finding is shown to have high importance on structural response, real earthquake records and reliability of conventionally employed numerical tools. Finally, short study of free field response in saturated soil reveals similar findings on higher harmonic generation. Secondly, two advanced soil constitutive models are used, and their performance is assessed based on examples of experimental data on piles in dry sand in order to validate the ability of the constitutive models to simulate seismic soil-structure interaction. The validation includes various experimental configurations and input motions. The discussion on the results focuses on constitutive and numerical modelling aspects. Some improvements in the formulations of the models are suggested based on the detailed investigation. Finally, the application of one of the advanced soil constitutive models is shown in regard to temporary natural frequency wandering observed in structures subjected to earthquakes. Results show that pore pressure generated during seismic events causes changes in soil stiffness, thus affecting the natural frequency of the structure during and just after the seismic event. Parametric studies present how soil permeability, soil density, input motion or a type of structure may affect the structural natural frequency and time for its return to the initial value. In addition, a time history with an aftershock is analysed to investigate the difference in structural response during the earthquake and the aftershock.
480

Transparency and learning spaces

Finau, Emily 08 April 2011 (has links)
This thesis explores the various meanings and implications of transparency in architecture and in learning environments in particular. Architectural transparency, achieved through choice of materials and principles of formal composition, creates a diversity of relationships and can facilitate visual, conceptual, and functional clarity as well as offering simultaneous perception of different spaces. It offers a range of phenomenological qualities and so provides an opportunity to explore and complicate such dichotomies as translucency and opacity, openness and closure, and public space and private space. While celebrated throughout modern and contemporary architecture, transparency raises issues of privacy and safety even as it breaks down hierarchies and social boundaries. The research-based design of transparency in a school building necessitates careful planning to achieve a balance between the access to views, natural light, fresh air, and social interaction that transparency may bring and the continuing obligation to provide a safe, secure environment for schoolchildren.

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