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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.
1141

Design and development of a power seat structure for a sports car

Fernández Cranz, Matías, Olsson, Hampus January 2021 (has links)
The purpose of this thesis is to develop a power seat structure that can serve as an alternativeto the one developed by Koenigsegg for their upcoming model Gemera and potentially others.The power seat structure will be designed around an existing chassis and will use it as areference to create an accommodating power seat structure. It will be designed to be used witha fixed-back seat that is used in the development process of the Gemera.Koenigsegg requires that the power seat structure allows for horizontal and lifting motion, aswell as tilting. These functions will be adapted to the power seat structure designed by theproject group.Due to confidentiality concerns, some parts of this thesis will not be made available to thepublic.
1142

Design Automation of Steam Turbine Diaphragms in NX : Research and implementation of design automation in a development process

Tellsén, Emil January 2021 (has links)
Siemens Energy develops, manufactures, and provides service of products utilized for production of green energy. This thesis has been conducted at Siemens Energy in Finspång and the department of steam turbine design. A major part of the work at the department includes service and updates of operating steam turbines located all around the world. The tasks of updating and service are short and require quick answers as the plant is waiting to be started. In order to adapt to the rapid development time required, the department of steam turbine design has developed a CAD automation process for drawing production of steam turbine diaphragms. The automation process is developed in an older CAD system that the department long have relied on. This CAD software and thus the automation process will soon be retired and taken out of service since the company is switching to the modern CAD software NX. This thesis is aimed at investigating the current development process at the department and propose and develop a new CAD automation process in NX for steam turbine diaphragms. The work was initiated by performing an analysis of the current situation where the collection of data constituted a solid ground for the rest of the thesis. The data lay the basis for the creation of a design specification which later served as a starting point for both the search and development of solution proposals regarding CAD automation. During the concept generation, it became clear that the development process embodied the scope of concepts, a form of application programming interface to achieve design automation was considered evident. This implied a more area-focused concept generation leading up to multiple solution concepts. After the generated solutions had been sorted and ranked, the solution to proceed with was based on NX integrated tool Knowledge Fusion to achieve CAD automation in NX. The development of the automation process and associated models utilized theories such as the MOKA methodology, high level cad templates and on explicit reference modeling. Resulting in a CAD automation process with possibilities to deliver both CAD models and technical drawings within a timeframe that reduces development time. It was concluded that the developed CAD automation process and associated models assured quality and reliability of the CAD material produced. Furthermore, the developed solution fit in the existing diaphragm development process and showed potential to significantly reduce the development time of steam turbine diaphragms.
1143

The advancement in 3D printing technology and its applications with bone grafting and dental implants

Chalabi, Amr 09 March 2022 (has links)
Since the late 20th century, breakthroughs in technology have been occurring expeditiously. Indeed, technological innovations have provided the betterment of many aspects of life and ensured humans’ appropriate forms of evolution and civilization. It is safe to claim that medicine has advanced within the past few decades, especially with the upbringing of technological innovations. The world of medicine would not have experienced its recent breakthroughs and profound discoveries without utilizing the available technology. The improvements observed in medicine and technology resulted in better providing of healthcare. Customizing treatments for each patient is now possible. One method of applying customization is through 3D printing of materials such as artificial prosthetics, tissues, and organs. This literature review analyzes 3D printing by stating definitions, assessing its history, discussing its different applications and closing with evaluating future directions. 3D printing first appeared in the late 20th century, and its primary purpose was to design and manufacture products efficiently and accurately. Traditional production of structures involves subtractive manufacturing (carving, cutting, and other methods of reshaping materials) to achieve desired products, whereas 3D printers implement additive manufacturing (a layer-by-layer approach). This provides less time, greater accuracy, and labor-free fabrication of products. Computerized software is one of the essential parts of 3D printing, and functions include designing, scaling, visualizing, controlling production frequency, and many more. In medical applications, the software may require CT scans, cone beam computed tomography, and intraoral scanners (for dental applications). The 3D printing techniques identified in this review are generally applied in oral and maxillofacial procedures—stereolithography, which constructs a product layer-by-layer through curing liquid resin using a UV laser. Digital light projection is a method similar to stereolithography, with a few differences, such as using a UV light instead of a laser and using a liquid crystal display panel. Fused deposition modeling is a technique that melts plastic filaments and extrudes them through a nozzle to form a structure in a layer-by-layer fashion. Selective laser sintering is also similar to stereolithography, where it uses a laser to form an object layer by layer, but the material is a thin layer of plastic powder instead of liquid resin. The power binder printing technique applies droplets onto powdered materials, adhering and forming layers as designed via computerized software. Lastly, computed axial lithography is similar to digital light projection, except the light is projected from many angles at once instead of one layer at a time. The main objectives of this literature review are to investigate each technique, discuss the advantages and disadvantages, and list the commonly applied areas in medicine for each. Also, this review evaluates the current limitations experienced when using 3D printers and suggestions for overcoming them. Some limitations include, but are not limited to, excessive time allocated for producing specific structures, accurate capturing of surgical sites, use of appropriate materials that form printed structures, cost, and deficiencies of reported data. Lastly, this literature review assesses the future projections. The future holds promising breakthroughs in 3D printing technology, including the fabrication of dental stem cells, operating artificial organs, complex vascular tissues, customized artificial alveolar structures for oral and intracranial procedures, and regeneration of periodontal tissues. These projections may occur by overcoming the most reported limitations. Medicine is digitizing rapidly and will continue adapting to the latest technological inventions. The current efforts to advance 3D printing technology will likely positively impact the advancement of many fields, including healthcare, increase chances of positive postoperative outcomes, and potentially combat many health issues society faces today. Professionals across disciplines must come together to further research and educate curriculums to revolve around the innovative technologies to continuing education courses related to 3-D printing technologies.
1144

Bildlärare i en virtuell bildmiljö

Lindh, Simon January 2018 (has links)
I föreliggande examensarbete undersöks hur gymnasieverksamma bildlärare förhåller sig till bild som form och digitala verktyg i undervisningen. Genom fyra stycken semistrukturerade intervjuer har jag fört samtal med gymnasielärare, där jag låtit lärarna få utveckla och definiera begrepp som form och bild. Jag har varit intresserad av att ta reda på vilket material och tekniskt hantverk bildlärare uppger att de använder sig av sin undervisning. En undervisning där digitala verktyg ska ha en allt mer framträdande roll (Regeringskansliet, 2017). Därför har jag velat undersöka hur gymnasieverksamma bildlärare uppger att de använder sig av digitala verktyg i bildundervisningen. För att ytterligare specificera min undersökning har min andra frågeställning handlat om tredimensionellt skapande i allmänhet och 3D-modellering i synnerhet. Jag har velat ta reda på hur användningen av 3D-modellering sker i bildundervisningen enligt gymnasieverksamma bildlärare. Till min hjälp har jag använt mig av fyra medieekologiska perspektiv som Anders Marner och Hans Örtegren formulerat utifrån den medieekologiska teoribildningen (Marner & Örtegren, 2013: Örtegren, 2013, s. 38). I Resultatet från föreliggande studie uppger alla fyra lärare att de implementerar digitala verktyg i sin undervisning, men att det skiljer sig åt på vilket sätt. Alla lärare påstår även att de arbetar med 3D-modellering, här varierar dock svaren på vilka grunder, samt i vilken omfattning.
1145

Automated Model Generation and Pre-Processing to Aid Simulation-Driven Design : An implementation of Design Automation in the Product Development process

Machchhar, Raj Jiten January 2020 (has links)
The regulations on emissions from a combustion engine vehicle are getting tougher with increasing awareness on sustainability, requiring the exhaust after-treatment systems to constantly evolve to the changes in the legislation. To establish a leading position in the competitive market, companies must adapt to these changes within a reasonable timeframe. With Scania’s extensive focus on Simulation-driven design, the product development process at Scania is highly iterative. A considerable amount of time is spent on generating a specific model for a simulation from the existing Computer-aided Design (CAD) model and pre-processing it. Thus, the purpose of this thesis is to investigate how design and simulation teams can collectively work to automatically generate a discretized model from the existing CAD model, thereby reducing repetitive work. As an outcome of this project, a method is developed comprising of two automation modules. The first module, proposed to be used by a design engineer, automatically generates a simulation-specific model from the existing CAD model. The second module, proposed to be used by a simulation engineer, automatically discretizes the model. Based on two case study assemblies, it is shown that the proposed method is significantly robust and has the potential to reduce product development time remarkably.
1146

Výroba a konstrukce čepového spoje pomocí CNC technologie

Baráková, Jana January 2017 (has links)
The main object of this theses is make research of issues relating to joints and CNC technology, find out information and apply this in design and manufacture of CNC tenon joint. The thesis contains definition of basic concepts, resource searching, background research, historical contexts introduction a basic information to exist theme. Teoretic part contains subjects relevant to joints in general, conventional joints, CNC joints, NC and CNC machine tools, CAD and CAM systems and NC programmes making. A part of the thesis is design of CNC tenon joint and its application on particular product. To design relates selection and application of proper materials, design documentation, 3D models and visualization exist product. The principal result of this theses should be manufactured prototype of designed product. In conclusion there are results review, incurred difficulties and its solutions.
1147

Calcul de gradient sur des paramètres CAO pour l’optimisation de forme / Gradient-based methods for shape optimization on CAD parameters

Leblond, Timothée 22 March 2017 (has links)
Dans ce manuscrit, nous présentons une méthode d’optimisation de forme qui se base sur des paramètres géométriques comme des longueurs, des angles, etc. Nous nous appuyons sur des techniques d’optimisation basées sur un gradient. La sensibilité de la fonction objectif par rapport à la position des noeuds du maillage nous est fournie par un solveur adjoint que l’on considère comme une boîte noire. Afin d’optimiser par rapport aux paramètres CAO, nous nous concentrons sur l’évaluation de la sensibilité de la position des noeuds par rapport à ces paramètres. Ainsi, nous proposons deux approches par différences finies. La première méthode s’appuie sur une projection harmonique afin de comparer dans un même espace le maillage initial et celui obtenu suite à la variation d’un paramètre CAO. Les développements présentés dans ce manuscrit permettent d’étendre l’application aux formes ayant plusieurs frontières comme les collecteurs d’échappement. Nous avons développé une méthode d’interpolation adaptée à cette comparaison. L’ensemble du processus a été automatisé et nous en montrons l’entière efficacité sur des applications industrielles en aérodynamique interne. La deuxième méthode se base directement sur les géométries CAO pour évaluer cette sensibilité. Nous utilisons la définition intrinsèque des patches dans l’espace paramétrique (u;v) pour effectuer cette comparaison. Grâce à l’utilisation des coordonnées exactes en tout point de la surface fournies par la CAO, nous évitons d’avoir recours à une interpolation afin d’avoir la meilleure précision de calcul possible. Cependant, contrairement à la première méthode, elle requiert d’identifier les correspondances entre les patches d’une forme à l’autre. Une application sur un cas académique a été faite en aérodynamique externe. La pertinence de la première méthode a été démontrée sur des cas représentatifs et multiobjectifs, ce qui permettrait de faciliter son déploiement et son utilisation dans un cadre industriel. Quant à la deuxième méthode, nous avons montré son fort potentiel. Cependant, des développements supplémentaires seraient nécessaires pour une application plus poussée. Du fait qu’elles sont indépendantes des solveurs mécaniques et du nombre de paramètres, ces méthodes réduisent considérablement les temps de développement des produits, notamment en permettant l’optimisation multiphysique en grande dimension. / In this manuscript, we present a shape optimization method based on CAD parameters such as lengths, angles, etc. We rely on gradient-based optimization techniques. The sensitivity of the objective function, with respect to the mesh nodes position, is provided by an adjoint solver considered here as a black box. To optimize with respect to CAD parameters, we focus on computing the sensitivity of the nodes positions with respect to these parameters. Thus, we propose two approaches based on finite differences. The first method uses a harmonic projection to compare in the same space the initial mesh and the one obtained after a change of the set of CAD parameters. The developments presented in this manuscript open up new doors like the application to shapes with multiple borders such as exhaust manifolds. We also developed an interpolation method suitable for this comparison. The entire process is automated, and we demonstrate the entire effectiveness on internal aerodynamics industrial applications. The second method is directly based on the CAD geometries to assess this sensitivity. To perform this comparison, we use the intrinsic definition of the patches in the parametric space (u;v). Through the use of the exact coordinates at any point on the surface provided by the CAD, we avoid using an interpolation to get the best calculation accuracy possible. However, unlike the first method, it requires to identify the correspondence between patches from one shape to another. An application on an external aerodynamics academic case was made. The relevance of the first method is demonstrated on a representative multi-objective case, which facilitate its deployment use in an industrial environment. Regarding the second method, we showed its great potential. However, further developments are needed to handle more advanced cases. Because they are independent of the mechanical solver and the number of parameters, these methods significantly reduce product development time, particularly by allowing large and multiphysics optimization.
1148

Stepwise stress testing of different CAD/CAM lithium disilicate veneer application methods to lithium disilicate substructure

May, Jaren Thomas January 2019 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Objective: CAD/CAM technology allows fabrication of thin lithium disilicate (LD) veneers to a LD crown substructure in place of using traditional feldspathic porcelain (FP) which has inferior mechanical properties. This project investigated the effect of different LD veneer applications to LD substructure on the biaxial flexural fatigue of LD veneer/substructure restorations. Materials/Methods: Forty-five LD discs (Ø = 120.7 mm) were fabricated that, when combined with the veneering discs, achieve final dimensions of (Ø = 121.2mm). Experimental groups were (n = 15) as follows: (1) Resin Bonded LD Veneer (RBLDV), LD veneer (Ø = 120.5 mm) adhesively cemented to LD (0.7 mm); (2) Sintered LD Veneer (SLDV), LD veneer (Ø=120.5 mm) sintered to LD (0.7 mm); (3) Sintered Feldspathic Veneer (SFV), feldspathic porcelain (FP) applied to LD discs to achieve a final dimension of (Ø = 121.2 mm). A fourth group of (1.2 mm) monolithic LD served as the control. Weibull-distribution survival analysis was used to compare the differences of the resistance to fracture after fatigue between groups. Total number of cycles were analyzed using one-way Anova (p < 0.05). Hypothesis: Adhering or sintering a thin laminate layer of LD on another LD surface would result in increased fracture resistance in comparison to sintered FP on LD. Results: The SFV group had significantly lower fatigue resistance than SLDV and RBLDV groups (p < 0.05). The RBLDV group fractures resulted in significantly more fractured fragments in comparison to the other groups. No statistical difference was observed in the number of cycles. The results also showed that the LD veneered groups presented similar resistance to fatigue as monolithic discs of the same overall dimensions. Conclusion: The hypothesis was accepted suggesting that veneering a LD substructure with a LD veneer, bonded or sintered, has increased resistance to fatigue as FP veneering material on a LD substructure. In addition, it was observed to have similar resistance to fatigue in comparison to the monolithic LD group.
1149

CODESIGN AND CONTROL OF SMART POWERED LOWER LIMB PROSTHESES

Abdelhadi, Mohamed January 2021 (has links)
No description available.
1150

Humor Styles and Acceptance as Predictors of Quality of Life in Men and Women with Coronary Artery Disease

Forrette, John Michael January 2019 (has links)
No description available.

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