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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.
1

Ceramic fabrication using a continuous inkjet printer

Blazdell, Philip Frank January 1998 (has links)
No description available.
2

Magnetic levitation and rotation for the feasibility of free-form machining

Shih, Alexander H. 27 August 2014 (has links)
This thesis presents a new transformative manufacturing methodology for free-form machining. An experimental prototype machine is constructed to levitate and rotate an object attached with sharp edges, which act as a cutter for the purpose of performing machining processes. This device aims to lead to a technological breakthrough, overcoming the limitation of the workpiece features, and achieve greater free-form machining capability. The construction of curved holes and interior surfaces are constrained by the geometry of the machine tool. The proposed concept creates a new device that uses a magnetic field generator as a base. It is loaded with a constant power imposing a vertical physical force to balance gravity and stabilize the cutting tool. With the uniqueness of a preferred orientation between the tool and the base, a rotating surface placed below the base permits the rotation of the cutting tool in order to achieve desired tool rotation speed. A smooth and controlled cut is achieved on a soft material. The result shows the feasibility of the device to achieve similar outcomes as a machine tool.
3

Monitoring system for free form modeling machines at Digital Mechanics

Hadley, Robin January 2010 (has links)
<p>Digital Mechanics is a company in Västerås manufacturing mainlyprototypes for it customers. To do this they use a number of free formingmachines. The building time of these machines differ very much from theestimated time required to build a job and this effects the efficiency of theproduction. The work presented in this paper is mainly about designing andconstructing a monitoring application for the machines at DigitalMechanics. The application will be used for alerting the operators when amachine is not building and preempt machines stopping because they runout of material to increase quality and efficiency in the production. Thesystem may also be used as the core of a future, more advanced, monitoringsystem.The thesis also included a study about how the estimation of the timerequired by the machines to build a job could be enhanced.Because of the nature of the business at Digital Mechanics theimprovement of quality and efficiency deriving from this monitoringapplication is difficult to measure, but the machine operators claim they areassisted by it.</p>
4

Jämförelse mellan progressiva glasögonglas : Är Free-form bättre än konventionella?

Citron, Christer January 2019 (has links)
Syfte: Syftet med denna studie var att jämföra upplevelsen av synfältsbredden och komforten i två olika progressiva glasögonglas med samma grunddesign, men som slipats enligt olika tekniker: Konventionell teknik och Free-form teknik. Metod: 16 personer med glasögonrefraktion inom ± 2,5 dioptrier, sfärisk ekvivalent deltog i studien. Könsfördelningen var 9 kvinnor och 7 män i åldrar från 43 till 74 år. Deltagarna fick först svara på ett antal allmänna frågor om glasögonvana mm. Därefter fick var och en testa ett par glasögon med den ena typen av progressivt glas i fem dagar, för att sen få prova den andra typen också i fem dagar. Testerna gjordes så att hälften fick börja med typ 1 och andra hälften med typ 2 utan att veta vilken man provade. Efter varje test utvärderades glasögonglasen med frågeformulär och mätning av synfältsbredden på 40 cm. Resultat: Det var ingen signifikant skillnad mellan synfältsbredd och komfort i progressiva glasögonglas av konventionell design ”Gamma” och Free-form design ”Gamma HD”. Slutsats: De flesta deltagare i den här studien upplever ingen större skillnad mellan progressiva glas med konventionell design ”Gamma” eller Free-form design ”Gamma HD” och är mycket nöjda generellt med komforten.
5

An optical measurement system to measure free form surfaces

Zou, Lifong January 2002 (has links)
Free form surface measurement and its subsequent analysis is becoming a subject of considerable interest, not only within the engineering field, but also in bioengineering, medical and dental research. In particular, within the field of dental research, the oral structures comprise a variety of complex free form surfaces, which are often recorded by elastomeric impression materials. In this study, an optical triangulation-based, noncontact probe fitted onto a Co-ordinate Measuring Machine was used to acquire three-dimensional co-ordinate data from such complex free form surfaces. When using an optical probe to digitise a complex free form surface represented by impressions, an optimal digitisation strategy is critical to limit the uncertainty of the data acquisition procedure, because the raw data are the basis for later surface measurement and analysis. This study attempted to optimise a method for three dimensional free form surface data acquisition, measurement and analysis. A theoretical and systematic analysis of error distribution was carried out using standard objects and optimal digitisation strategies were proposed in relation to specified models. Two simulation models of two typical human tooth surfaces were extensively analysed and evaluated. Three reference systems were developed for comparative measurements of those surfaces that have fewer geometrical features. An integrated automatic data acquisition procedure was also developed to scan a large number of impressions. Several successful research applications have been carried out using the methodology developed in this study.
6

Morphing-Based Shape Optimization in Computational Fluid Dynamics

ROUSSEAU, Yannick, MEN'SHOV, Igor, NAKAMURA, Yoshiaki 04 May 2007 (has links)
No description available.
7

Monitoring system for free form modeling machines at Digital Mechanics

Hadley, Robin January 2010 (has links)
Digital Mechanics is a company in Västerås manufacturing mainlyprototypes for it customers. To do this they use a number of free formingmachines. The building time of these machines differ very much from theestimated time required to build a job and this effects the efficiency of theproduction. The work presented in this paper is mainly about designing andconstructing a monitoring application for the machines at DigitalMechanics. The application will be used for alerting the operators when amachine is not building and preempt machines stopping because they runout of material to increase quality and efficiency in the production. Thesystem may also be used as the core of a future, more advanced, monitoringsystem.The thesis also included a study about how the estimation of the timerequired by the machines to build a job could be enhanced.Because of the nature of the business at Digital Mechanics theimprovement of quality and efficiency deriving from this monitoringapplication is difficult to measure, but the machine operators claim they areassisted by it.
8

Real-time Rendering of Burning Objects in Video Games

Amarasinghe, Dhanyu Eshaka 08 1900 (has links)
In recent years there has been growing interest in limitless realism in computer graphics applications. Among those, my foremost concentration falls into the complex physical simulations and modeling with diverse applications for the gaming industry. Different simulations have been virtually successful by replicating the details of physical process. As a result, some were strong enough to lure the user into believable virtual worlds that could destroy any sense of attendance. In this research, I focus on fire simulations and its deformation process towards various virtual objects. In most game engines model loading takes place at the beginning of the game or when the game is transitioning between levels. Game models are stored in large data structures. Since changing or adjusting a large data structure while the game is proceeding may adversely affect the performance of the game. Therefore, developers may choose to avoid procedural simulations to save resources and avoid interruptions on performance. I introduce a process to implement a real-time model deformation while maintaining performance. It is a challenging task to achieve high quality simulation while utilizing minimum resources to represent multiple events in timely manner. Especially in video games, this overwhelming criterion would be robust enough to sustain the engaging player's willing suspension of disbelief. I have implemented and tested my method on a relatively modest GPU using CUDA. My experiments conclude this method gives a believable visual effect while using small fraction of CPU and GPU resources.
9

‘‘Push/pull’ …cloth directed”. Exploring possible draping techniques based on Madame Gres’ method to create shape and fo

MKHABELA, IRMGARD January 2014 (has links)
This study is concerned with the development of a method for creating shapes and form in clothing with minimum exertion on the cloth, using simple construction techniques. It is an exploration of an approach to producing clothing in a less familiar manner to the usual way of working which involves, almost always, drafting or flat-pattern making. With the expression of the movement of the textile around the body as the main aim, the ‘push/pull’ principle is employed to direct its flow in both a symmetric and asymmetric fashion. It is a principle inspired by Madame Gres, the French designer of the 1930s to 1980s, famous for her neo-classic inspired gowns. The textile, usually a rectangle, is manipulated without cutting into it but by pushing and pulling first, through the upper limbs of the body, and then ‘worked’ around the rest of the body, using draping and pleating to create shapes which are spontaneous, elaborate and not pre-determined. Furthermore, the approach explores the aesthetic potential of draping and combining the Filter 80 PPI, an industrial textile used for filtering, with conventional clothing materials, linen and/or cotton in this case. The parallels and constasts of this mix are noted, together with the distinct expressions, which nonetheless both display a simple approach in construction, minimal manipulation of the textile, the use of the upper limbs as natural obstacles, and the ‘no-cut’ principle of the rectangular piece of cloth. With free form construction and reflection, one discovers expressions possible only through the use of an experimental approach in working. / Program: Master Programme in Fashion and Textile Design
10

Shape theory and mathematical design of a general geometric kernel through regular stratified objects

Gomes, Abel Joao Padrao January 2000 (has links)
This dissertation focuses on the mathematical design of a unified shape kernel for geometric computing, with possible applications to computer aided design (CAM) and manufacturing (CAM), solid geometric modelling, free-form modelling of curves and surfaces, feature-based modelling, finite element meshing, computer animation, etc. The generality of such a unified shape kernel grounds on a shape theory for objects in some Euclidean space. Shape does not mean herein only geometry as usual in geometric modelling, but has been extended to other contexts, e. g. topology, homotopy, convexity theory, etc. This shape theory has enabled to make a shape analysis of the current geometric kernels. Significant deficiencies have been then identified in how these geometric kernels represent shapes from different applications. This thesis concludes that it is possible to construct a general shape kernel capable of representing and manipulating general specifications of shape for objects even in higher-dimensional Euclidean spaces, regardless whether such objects are implicitly or parametrically defined, they have ‘incomplete boundaries’ or not, they are structured with more or less detail or subcomplexes, which design sequence has been followed in a modelling session, etc. For this end, the basic constituents of such a general geometric kernel, say a combinatorial data structure and respective Euler operators for n-dimensional regular stratified objects, have been introduced and discussed.

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