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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

Application of welding to a large civil aircraft wing

Meo, Michele January 1999 (has links)
No description available.
2

Computer aided model structuring in system design

Huang, GongWen, 1948- January 1988 (has links)
As a CAD tool, the Computer Aided Model Structuring System (call MOSTS in the following text) for model structuring in system design and system simulation has been designed and implemented. First, this MOSTS allows system design experts to create and save System Data Bases (SDBs) for model structuring in system design and simulation. Then, these SDBs can be retrieved, modified, and finally used to structure system models by design engineers. The MOSTS pursues the model structuring process in such a way that the model structure having the best performance (according to the expert's knowledge and the design engineer's design criteria) will be generated first, and then the second best model, the third best model, and so on.
3

High-level, product type-specific programmatic operations for streamlining associative computer-aided design /

Scott, Nathan W., January 2008 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2008. / Includes bibliographical references (p. 97-98).
4

BIODIESEL PRODUCTION USING SUPPORTED 12-TUNGSTOPHOSPHORIC ACID AS SOLID ACID CATALYSTS

2014 December 1900 (has links)
Biodiesel has achieved worldwide recognition for many years due to its renewability, lubricating property, and environmental benefits. The abstract represents a summary of all the chapters of the thesis. The research chapters are defined as research phases in the abstract. The thesis starts with an introduction followed by literature review. In the literature review, all the necessary data were collected reviewing the literature. Then an artificial neural network model (ANN) was built based on the published research data to capture the general trends or to make predictions. Both catalyst properties and reaction conditions were trended and predicted using the network model. The review study revealed that esterification and transesterification required catalysts with slightly different properties. In the first phase of the study, biodiesel production using 12-Tungstophosphric acid (TPA) supported on SBA-15 as a solid acid catalyst was studied. In this phase of the study, a large number of 0-35% TPA on SBA-15 catalysts were synthesized by impregnation method and the effects of various operating conditions such as–catalyst wt.% and methanol to oil molar ratio on the transesterification of model feedstock Triolein were studied. A 25% TPA loading was found to be the optimum. A 4.15 wt.% catalysts (based on Triolein) and 39:1 methanol to Triolein molar ratio was found to be the optimum reaction parameter combination, when the reaction temperature was kept fixed at 200C, stirring speed of 600 rpm and 10 h reaction time. The biodiesel yield obtained using this condition was 97.2%. In the second phase of the study, a 12-Tungstophosphoric acid (TPA) was supported by using organic functional group (i.e. 3-aminopropyltriethoxysilane (APTES)) and was incorporated into the SBA-15 structure. A 45 wt.% TPA incorporated SBA-15 produced an ester with biodiesel yield of 97.3 wt.%, when 3 wt.% catalyst (based on the green seed canola (GSC) oil) and 25.8:1 methanol GSC oil molar ratio were used at 2000C for reaction time of 6.2 h. In the third phase, process sustainability (i.e. process economics, process safety, energy efficiency, environmental impact assessment) studies were conducted based on the results obtained in phase three. Based on the study, it was concluded that heterogeneous acid catalyzed process had higher profitability as compared to the homogeneous acid catalyzed process. Additionally, it was obtained that heterogeneous acid catalyzed process was safe, more energy efficient and more environment friendly than homogenous process. In the fourth phase, the catalytic activity of Tungsten oxide (WO3) and TPA supported (by impregnation) on H-Y, H-β and H-ZSM-5 zeolite catalysts were tested for biodiesel production from Green Seed Canola (GSC) oil. In this phase iii of the study, TPA/H-Y and TPA/H- zeolite were proved to be effective catalysts for esterification and transesterification, respectively. A 55% TPA/H- showed balanced catalytic activity for both esterification and transesterification. It yielded 99.3 wt.% ester, when 3.3 wt.% catalyst (based on GSC oil) and 21.3:1 methanol to GSC oil molar ratio were used at 200C, reaction pressure of 4.14 MPa and reaction time of 6.5 h. Additionally, this catalyst (55% TPA/H-) was experimented for etherification of pure glycerol, and maximum conversion of glycerol (100%) was achieved in 5 h at 120C, 1 MPa, 1:5 molar ratio (glycerol: (tert-butanol) TBA), 2.5% (w/v) catalyst loading. Later, these conditions were used to produce glycerol ether successfully from the glycerol derived after transesterification of green seed canola oil. A mixture of GSC derived biodiesel, and glycerol ether was defined as biofuels. In the fifth phase, catalytic activity of H-Y supported TPA (using different impregnation methods) was studied in details further for esterification of free fatty acid (FFA) of GSC oil. From the optimization study, 97.2% FFA (present in the GSC oil) conversion was achieved using 13.3 wt.% catalyst, 26:1 methanol to FFA molar ratio at 120C reaction temperature and 7.5 h of reaction time. In the sixth- and final phase, techno-economic and ecological impacts were compared between biodiesel and combined biofuel production processes based on the results obtained in phase four. Based on the study, it was concluded that, biodiesel production process had higher profitability as compared to that for combined biofuel production process. Additionally, biodiesel production process was more energy efficient than combined biofuel production process. However, combined biofuel production process was more environment-friendly as compared to that for biodiesel production process.
5

Design, Modeling and Simulation of Planar Waveguide Optical Splitter

Huang, Min 07 1900 (has links)
<p> 1-by-N optical power splitters are primary components in the field of integrated optics and optical transmission systems. Planar waveguide optical power splitters are key devices to realize low-cost optical transmission systems through photonic integration. The goal of this thesis is to design, model and simulate a novel planar waveguide optical power splitter for optical transmission systems and Fiber to the Home (FTTH) networks.</p> <p> The first chapter is an introduction. This chapter gives the background of power splitter, reviews the existing devices and explains why our novel design is needed.</p> <p> The idea of this novel power splitter is presented in Chapter 2, including analytical formulations, theoretical calculations and designs. This serves as a theoretical foundation for the development and verification of different parts presented in Chapter 3. The novel power splitter design is composed of a series of waveguide lenses and waveguide phase shifts. The analytical formulations are derived and intensive numerical simulations are performed to verify and investigate this new power splitter. Also the conventional Beam Propagation Method (BPM) is studied in this chapter, which provides a numerical preparation for the device simulation and design in the subsequent chapter.</p> <p> The design results are shown in Chapter 4. The novel power splitter design predicts good performance with more compact device size, better output and smaller wavelength dependence. This chapter demonstrated the possibility of new power splitter working as a better approach to the existing MMI or other structures.</p> <p> Finally, Chapter 5 gives a conclusion to this thesis. The limitations of this work are presented and the future works are proposed.</p> / Thesis / Master of Applied Science (MASc)
6

A versatile multi-material virtual prototyping system

Cheung, Hoi-hoi., 張凱凱. January 2007 (has links)
published_or_final_version / abstract / Industrial and Manufacturing Systems Engineering / Doctoral / Doctor of Philosophy
7

Building an expert system shell for design model synthesis in logic programming

Huang, Yueh-Min, 1960- January 1987 (has links)
This thesis implemented a prototype of an expert system shell for support of engineering design activities in the way of logic programming. The development of the system is based on the theoretical framework for knowledge-based system design and the formal modeling concepts. Under the above methodologies, two knowledge representations, production rule system and system entity structure, are incorporated into the knowledge base for figuring design structures. Here the production system scheme is employed for synthesis of design models represented in the system entity structure. The whole system is coded in Turbo Prolog and a specific domain knowledge, namely a local area network, is currently used as a testbed environment.
8

A computational framework for structure-based drug discovery with GPU acceleration.

January 2011 (has links)
Li, Hongjian. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 132-156). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract in Chinese --- p.iii / Acknowledgement --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.2 / Chapter 1.2 --- Objective --- p.2 / Chapter 1.3 --- Method --- p.3 / Chapter 1.4 --- Outline --- p.4 / Chapter 2 --- Background --- p.7 / Chapter 2.1 --- Overview of the Pharmaceutical Industry --- p.7 / Chapter 2.2 --- The Process of Modern Drug Discovery --- p.10 / Chapter 2.2.1 --- Development of an Innovative Idea --- p.10 / Chapter 2.2.2 --- Establishment of a Project Team --- p.11 / Chapter 2.2.3 --- Target Identification --- p.11 / Chapter 2.2.4 --- Hit Identification --- p.12 / Chapter 2.2.5 --- Lead Identification --- p.13 / Chapter 2.2.6 --- Lead Optimization --- p.14 / Chapter 2.2.7 --- Clinical Trials --- p.14 / Chapter 2.3 --- Drug Discovery via Computational Means --- p.15 / Chapter 2.3.1 --- Structure-Based Virtual Screening --- p.16 / Chapter 2.3.2 --- Computational Synthesis of Potent Ligands --- p.20 / Chapter 2.3.3 --- General-Purpose Computing on GPU --- p.23 / Chapter 3 --- Approximate Matching of DNA Patterns --- p.26 / Chapter 3.1 --- Problem Definition --- p.27 / Chapter 3.2 --- Motivation --- p.28 / Chapter 3.3 --- Background --- p.30 / Chapter 3.4 --- Method --- p.32 / Chapter 3.4.1 --- Binary Representation --- p.32 / Chapter 3.4.2 --- Agrep Algorithm --- p.32 / Chapter 3.4.3 --- CUDA Implementation --- p.34 / Chapter 3.5 --- Experiments and Results --- p.39 / Chapter 3.6 --- Discussion --- p.44 / Chapter 3.7 --- Availability --- p.45 / Chapter 3.8 --- Conclusion --- p.47 / Chapter 4 --- Structure-Based Virtual Screening --- p.50 / Chapter 4.1 --- Problem Definition --- p.51 / Chapter 4.2 --- Motivation --- p.52 / Chapter 4.3 --- Medicinal Background --- p.52 / Chapter 4.4 --- Computational Background --- p.59 / Chapter 4.4.1 --- Scoring Function --- p.59 / Chapter 4.4.2 --- Optimization Algorithm --- p.65 / Chapter 4.5 --- Method --- p.68 / Chapter 4.5.1 --- Scoring Function --- p.69 / Chapter 4.5.2 --- Inactive Torsions --- p.72 / Chapter 4.5.3 --- Optimization Algorithm --- p.73 / Chapter 4.5.4 --- C++ Implementation Tricks --- p.74 / Chapter 4.6 --- Data --- p.75 / Chapter 4.6.1 --- Proteins --- p.75 / Chapter 4.6.2 --- Ligands --- p.76 / Chapter 4.7 --- Experiments and Results --- p.77 / Chapter 4.7.1 --- Program Validation --- p.77 / Chapter 4.7.2 --- Virtual Screening --- p.81 / Chapter 4.8 --- Discussion --- p.89 / Chapter 4.9 --- Availability --- p.90 / Chapter 4.10 --- Conclusion --- p.91 / Chapter 5 --- Computational Synthesis of Ligands --- p.92 / Chapter 5.1 --- Problem Definition --- p.93 / Chapter 5.2 --- Motivation --- p.93 / Chapter 5.3 --- Background --- p.94 / Chapter 5.4 --- Method --- p.97 / Chapter 5.4.1 --- Selection --- p.99 / Chapter 5.4.2 --- Mutation --- p.102 / Chapter 5.4.3 --- Crossover --- p.102 / Chapter 5.4.4 --- Split --- p.103 / Chapter 5.4.5 --- Merging --- p.104 / Chapter 5.4.6 --- Drug Likeness Testing --- p.104 / Chapter 5.5 --- Data --- p.105 / Chapter 5.5.1 --- Proteins --- p.105 / Chapter 5.5.2 --- Initial Ligands --- p.107 / Chapter 5.5.3 --- Fragments --- p.107 / Chapter 5.6 --- Experiments and Results --- p.109 / Chapter 5.6.1 --- Binding Conformation --- p.112 / Chapter 5.6.2 --- Free Energy and Molecule Weight --- p.115 / Chapter 5.6.3 --- Execution Time --- p.116 / Chapter 5.6.4 --- Support for Phosphorus --- p.116 / Chapter 5.7 --- Discussion --- p.120 / Chapter 5.8 --- Availability --- p.123 / Chapter 5.9 --- Conclusion --- p.123 / Chapter 5.10 --- Personal Contribution --- p.124 / Chapter 6 --- Conclusion --- p.125 / Chapter 6.1 --- Conclusion --- p.125 / Chapter 6.2 --- Future Work --- p.128 / Chapter A --- Publications --- p.130 / Chapter A.1 --- Conference Papers --- p.130 / Chapter A.2 --- Journal Papers --- p.131 / Bibliography --- p.132
9

The digital craftsperson : an investigation into digital tools/processes/craft

Vermillion, Joshua D. January 2005 (has links)
One potential role for the architect of the future will be that of the digital craftsperson. Digital technology is allowing the designer to take control of and retool the entire design I fabrication I assembly process. With this new power, architects are crafting the digital tools and processes required to make architecture for the digital age.First, this thesis examines the notion of craft in the traditional way—how it has applied to architecture and building for most of history. This story recounts the architect's role in the designing and making of architecture, from the medieval master mason to the present-day architect. Craft, it is argued, is based on an understanding and skillful application of tools and processes as they relate to designing and making.The second part of this thesis applies this definition of craft to a new set of digital skills, tools, and processes. Digital craft is a combination of the skills of the architect, augmented by computers and computer-driven machines. Designing and making with digital tools is very dependent on a feedback loop driven process centered around a digital master model, into which, design information and data is input, and direct fabrication information and representation is output.The third part of this thesis describes the digital craftsperson through three case studies. The first case study recounts the process of digital tool-making. The second, describes the development of innovative fabrication and assembly techniques using digital tools and unconventional materials. The last case study recounts the design and fabrication process of a full-scale prototype by the author and a team of students. / Department of Architecture
10

Knowledge composition methodology for effective analysis problem formulation in simulation-based design

Bajaj, Manas. January 2008 (has links)
Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Co-Chair: Dr. Christiaan J. J. Paredis; Committee Co-Chair: Dr. Russell S. Peak; Committee Member: Dr. Charles Eastman; Committee Member: Dr. David McDowell; Committee Member: Dr. David Rosen; Committee Member: Dr. Steven J. Fenves. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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