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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

Sukamų daugiasluoksnių konstrukcinių elementų projektavimo proceso modeliavimas / The Modeling of Design of Multi-layer Construction Elements Subjected by Turning

Zacharovienė, Elvyra 10 September 2004 (has links)
Program „The modeling of design of multi-layer construction elements subjected by turning“ is created for students of mechanical engineering course and designers. Using this program it is possible to calculate inertia momentum of pole area, stiffness for shear, shear stresses, and maximum meanings of shear stress and twisting angle. The input parameters are shear modulus of materials, inner diameter of pivot, thickness and material of each layer, torsion moment and length of pivot. The output is initial data and results of calculation. In addition the diagram of distribution of stresses is drawn.
2

3D Printable Multilayer RF Integrated System

Yu, Xiaoju, Liang, Min, Shemelya, Corey 10 1900 (has links)
ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / In this work, a 3D-printable multilayer phased array system is designed to demonstrate the applicability of additive manufacturing technique combining dielectric and conductor processes at room temperature for RF systems. Phased array systems normally include feeding networks, antennas, and active components such as switches, phase shifters and amplifiers. To make the integrated system compact, the array system here uses multilayer structure that can fully utilize the 3D space. The vertical interconnections between layers are carefully designed to reduce the loss between layers. Simulated results show good impedance matching and high-directive scanning beam. This multilayer phased array will finally be 3D printed by integrating thermal / ultrasound wire mesh embedding method (for metal) and fused-deposition-modeling technique (for dielectric).
3

Inverse Heat Conduction Approach for Infrared Non-destructive Testing of Single and Multi-layer Materials

Borazjani, Ehsan 22 June 2012 (has links)
The focus of this thesis is to derive analytical tools for the design of infrared nondestructive tests in single and multi layer material bodies. This requires the predetermination of the parameters of the experiment such that the infrared image has the required resolution for defect detection. Inverse heat conduction in single and multi-layer materials is investigated to determine the required frequency of excitation in order to obtain a desired temperature at the observation point. We use analytical quadrupole representation to derive a polynomial relation to estimate the frequency of the periodic excitation as a function of the temperature amplitude at a given observation point within the body. The formula includes characteristic geometric and material parameters of the system. The polynomial formula can be an e ective design tool for quick frequency predetermination in the design of non-destructive testing experiments with infrared thermography. The convergence and accuracy of the formula is assessed by comparison with the analytical thermal quadrupole solution and experimental results. We also investigate the e ect of the nite length of the material domain in order to establish the range of applicability of a simpli ed formula based on semi-in nite domain assumption. The e ect of nite length is investigated analytically by using (i) Fourier series which accounts for transients and (ii) Time varying solution associated to the steady state solution when a purely periodic excitation is applied. These results are also compared with numerical solution obtained with commercial nite element software ANSYSTM.
4

Inverse Heat Conduction Approach for Infrared Non-destructive Testing of Single and Multi-layer Materials

Borazjani, Ehsan 22 June 2012 (has links)
The focus of this thesis is to derive analytical tools for the design of infrared nondestructive tests in single and multi layer material bodies. This requires the predetermination of the parameters of the experiment such that the infrared image has the required resolution for defect detection. Inverse heat conduction in single and multi-layer materials is investigated to determine the required frequency of excitation in order to obtain a desired temperature at the observation point. We use analytical quadrupole representation to derive a polynomial relation to estimate the frequency of the periodic excitation as a function of the temperature amplitude at a given observation point within the body. The formula includes characteristic geometric and material parameters of the system. The polynomial formula can be an e ective design tool for quick frequency predetermination in the design of non-destructive testing experiments with infrared thermography. The convergence and accuracy of the formula is assessed by comparison with the analytical thermal quadrupole solution and experimental results. We also investigate the e ect of the nite length of the material domain in order to establish the range of applicability of a simpli ed formula based on semi-in nite domain assumption. The e ect of nite length is investigated analytically by using (i) Fourier series which accounts for transients and (ii) Time varying solution associated to the steady state solution when a purely periodic excitation is applied. These results are also compared with numerical solution obtained with commercial nite element software ANSYSTM.
5

Recent Developments in and Challenges of Photonic Networking Technologies

SATO, Ken-ichi 01 March 2007 (has links)
No description available.
6

Lenkiamų daugiasluoksnių konstrukcinių elementų projektavimoproceso modeliavimas / The Model for Design of Multi-layer Construction Elements Subjected by Bending

Padaigienė, Regina 13 September 2004 (has links)
Multi-layer construction elements improve technical characteristics of the product. There is exhaustive analysis of software in this work. Besides that the model for design of multi-layer construction elements subjected by bending is created in this work. The purpose of this program is calculation of stiffness and stresses for multi-layer constructions subjected by cross forces and bending moments. Modeling the design process of multi-layer construction elements is simple task that can be automatized by creation of modeling system. This program allows to calculate stiffness and strength of multi-layer construction elements subjected by cross forces and bending moments. It is possible to design various constructions of beams changing different parameters. The programme itself is simple for every student, engineer.This model can be used for scientific research, engineering calculations, laboratorial calculations. The program allows to evaluate strength of multi-layer construction element subjected by bending. The construction will not hold out external load if intensity of stresses in one layer exceeds permissible stresses of strength limit of this layer material. The report is given in such case. The distribution of calculated stresses in cross-section of multi-layer construction elements can be shown graphically. It significantly facilitate designer’s work.
7

The feasibility and application of multi–layer vacuum insulation for cryogenic hydrogen storage / Hodgman J.H.

Hodgman, Jacobus Henry January 2011 (has links)
A need was identified to test multi–layer vacuum super insulation (MLVSI) used in cryogenic applications for hydrogen storage. The study focuses on the application of commercially available MLVSI to a locally patented liquid hydrogen cryogenic storage system. This led to an investigation of different types of multi–layer vacuum insulation configurations, as well as further research on tank inlet coupling configurations. It includes the manufacturing of a liquid nitrogen testing cryostat to be able to test and evaluate the system performance. The first set of tests was based on the development of an inlet coupling configuration to limit heat transfer through the inner tank inlet, of a double cryogenic tank system in order to reduce gas boil–off. The couplings were manufactured in the form of a bellow to handle cryogenic vacuum levels, while ensuring low heat transfer rates between inner and outer tanks. It was found that various coupling designs can be considered to limit gas boil–off. The second set of tests was conducted on a specific MLVSI configuration to determine its effectiveness to insulate the spherical header surface of a typical hydrogen storage vessel. The installation procedure, to limit heat transfer and boil–off due to edge effects in this configuration was investigated. It was found that insulation–overlap–edge effects will always have an impact on insulation performance when a spherical header of a storage vessel is insulated, due to its specific geometry. A time efficient way to install MLVSI on such a spherical header is presented and evaluated. Further investigations were carried out by combining findings into one single system to determine the performance of an optimised insulated cryogenic system. It was found that copper plate discs installed between the vanes of a bellowed inlet/outlet nozzle is the most promising to limit heat transfer to the cryogenic fluid. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.
8

The feasibility and application of multi–layer vacuum insulation for cryogenic hydrogen storage / Hodgman J.H.

Hodgman, Jacobus Henry January 2011 (has links)
A need was identified to test multi–layer vacuum super insulation (MLVSI) used in cryogenic applications for hydrogen storage. The study focuses on the application of commercially available MLVSI to a locally patented liquid hydrogen cryogenic storage system. This led to an investigation of different types of multi–layer vacuum insulation configurations, as well as further research on tank inlet coupling configurations. It includes the manufacturing of a liquid nitrogen testing cryostat to be able to test and evaluate the system performance. The first set of tests was based on the development of an inlet coupling configuration to limit heat transfer through the inner tank inlet, of a double cryogenic tank system in order to reduce gas boil–off. The couplings were manufactured in the form of a bellow to handle cryogenic vacuum levels, while ensuring low heat transfer rates between inner and outer tanks. It was found that various coupling designs can be considered to limit gas boil–off. The second set of tests was conducted on a specific MLVSI configuration to determine its effectiveness to insulate the spherical header surface of a typical hydrogen storage vessel. The installation procedure, to limit heat transfer and boil–off due to edge effects in this configuration was investigated. It was found that insulation–overlap–edge effects will always have an impact on insulation performance when a spherical header of a storage vessel is insulated, due to its specific geometry. A time efficient way to install MLVSI on such a spherical header is presented and evaluated. Further investigations were carried out by combining findings into one single system to determine the performance of an optimised insulated cryogenic system. It was found that copper plate discs installed between the vanes of a bellowed inlet/outlet nozzle is the most promising to limit heat transfer to the cryogenic fluid. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.
9

Rule extraction and knowledge transfer from radial basis function neural networks

McGarry, Kenneth J. January 2002 (has links)
No description available.
10

Inverse Heat Conduction Approach for Infrared Non-destructive Testing of Single and Multi-layer Materials

Borazjani, Ehsan January 2012 (has links)
The focus of this thesis is to derive analytical tools for the design of infrared nondestructive tests in single and multi layer material bodies. This requires the predetermination of the parameters of the experiment such that the infrared image has the required resolution for defect detection. Inverse heat conduction in single and multi-layer materials is investigated to determine the required frequency of excitation in order to obtain a desired temperature at the observation point. We use analytical quadrupole representation to derive a polynomial relation to estimate the frequency of the periodic excitation as a function of the temperature amplitude at a given observation point within the body. The formula includes characteristic geometric and material parameters of the system. The polynomial formula can be an e ective design tool for quick frequency predetermination in the design of non-destructive testing experiments with infrared thermography. The convergence and accuracy of the formula is assessed by comparison with the analytical thermal quadrupole solution and experimental results. We also investigate the e ect of the nite length of the material domain in order to establish the range of applicability of a simpli ed formula based on semi-in nite domain assumption. The e ect of nite length is investigated analytically by using (i) Fourier series which accounts for transients and (ii) Time varying solution associated to the steady state solution when a purely periodic excitation is applied. These results are also compared with numerical solution obtained with commercial nite element software ANSYSTM.

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