1,720,983 research outputs found
U-Kite development
Get PDFThe Following thesis describes the work which was undertaken in the conception, development, and the construction of an open sea towed vehicle used to deploy a wide range of oceanographic monitoring equipment. This streamlined submersible vehicle, is towed alongside a ship or small vessel, and remains slightly buoyant at all times, but once it is moving it uses its wings which are configured upside-down with respect to those on an aircraft to pull it down to depth and move it away from the towing vessels wake and wave system, while assuring lateral stability. The Preliminary design requirement called for a light, robust, stable, simple, and low cost platform able to operate in a close to rough sea surface, and can be worked from a relatively small vessels such as those used for surveys of estuaries and coastal. During the design phase of this project, tools such as parametric feature based solid modelling, computational fluid dynamics, and finite element analysis were employed to provide a solution to the problem. A prototype was built using CADCAM technology, and strong composite materials
Development of a semi-automatic self learning pattern recognition system for the control of electronic boards
Get PDFThis project was funded under the Applied Research Grants Scheme administered by Enterprise Ireland. The project was a partnership between Galway - Mayo Institute of Technology and an industrial company, Tyco/Mallinckrodt Galway. The project aimed to develop a semi - automatic, self - learning pattern recognition system capable of detecting defects on the printed circuits boards such as component vacancy, component misalignment, component orientation, component error, and component weld. The research was conducted in three directions: image acquisition, image filtering/recognition and software development. Image acquisition studied the process of forming and digitizing images and some fundamental aspects regarding the human visual perception. The importance of choosing the right camera and illumination system for a certain type of problem has been highlighted. Probably the most important step towards image recognition is image filtering, The filters are used to correct and enhance images in order to prepare them for recognition. Convolution, histogram equalisation, filters based on Boolean mathematics, noise reduction, edge detection, geometrical filters, cross-correlation filters and image compression are some examples of the filters that have been studied and successfully implemented in the software application. The software application developed during the research is customized in order to meet the requirements of the industrial partner. The application is able to analyze pictures, perform the filtering, build libraries, process images and generate log files. It incorporates most of the filters studied and together with the illumination system and the camera it provides a fully integrated framework able to analyze defects on printed circuit boards
A low cost free drifting position transmitter for the measurement of the thermocline properties
Get PDFThis thesis describes the work undertaken in the conception o f a vehicle able to observe the thermocline, the temperature and the salinity from the sea surface to 200m deep. This work includes the mechanical design of the device, termed a “ballast system” or “subsurface profiler” and the control of its velocity. This profiler is able to accommodate sensors capable of collecting such data (temperature and salinity). These sensors are provided by Sea-Sense Ltd, Galway. The profiler is designed to be disposable, auto-controlled and located by satellites in order to eliminate the recovery cost. It is designed to achieve at least two hundred cycles from the sea surface to 200m deep. Furthermore, the profiler velocity must be controlled accurately and as close as possible to O.OSm-s"1. Once the mechanical design and the selection of the appropriate sensors mounting components are achieved, the mechanical strength of the profiler, using appropriate materials, is evaluated at 200m deep where the pressure is relatively high (about 20 bars). The profiler velocity is simulated via a motor, which pumps (discharges) water in order to become heavier (lighter). Tools such as mechanical design automation software, finite element analysis and dynamical simulation systems software were employed to provide a solution to each problem through this project
Factors influencing the mechanical behaviour of small devices such as stents
Get PDFA coronary stent is a mechanical device designed to open arteries that have been occluded. The manufacturing of stents involves the laser cutting of specific designs in stainless steel tubes. In order to determine factors influencing the mechanical behaviour of stents, tensile tests were performed on struts laser-cut in tubes used for the manufacturing of stents. The hardening curves obtained show that the yield stress and Young’s Modulus increase when the width of the struts decreases, until a limit is reached where they start decreasing again; the breaking point varies inversely. To confirm the results a three-point bending test was conducted. Because the struts are cut in a tube, the resulting geometry makes it difficult to predict the mechanical behaviour. A model using Finite Element Analysis (F.E.A.) was therefore created and the mechanical behaviour identified by comparing the experimental results and the F.E.A. prediction. The hardening curves obtained confirm the conclusions reached in tension. In order to understand the phenomenon, the accuracy of laser cutting was investigated. An F.E.A. was conducted, showing that the inaccuracy of laser cutting can only explain the strain at breaking decreasing with the width. The geometry of the specimen being discarded, the microstructure was examined in order to understand the mechanical behaviour. The Heat Affected Zone (H.A.Z.) resulting from laser cutting was first observed. It was found that the size of the H.A.Z. is negligible when considering wide struts but becomes significant when dealing with struts smaller than a millimetre. Consequently, the strut behaves like a sandwich material partly explaining the experimental results. However, according to the sandwich theory, the yield stress, Young’s Modulus and strain at breaking should be linear functions of the width which is not the case. Therefore, another factor has to be considered. The number of grains in the width was then investigated and shown to explain the other part of the experimental results. In conclusion, the number of grains in the width and the H.A.Z. both influence the mechanical behaviour of the struts
Development of a method for the characterisation of the compliance and stiffness matrices of uncoupled laminates
Get PDFThe mechanical behaviour of composite materials is defined by three matrices of\ud
stiffness/compliance : in-plane, flexure and coupling matrix between in-plane and\ud
flexure. The present work gives a method of test to characterise the in-plane\ud
compliance matrix of uncoupled laminates. The matrix depends on the direction,\ud
hence the polar coordinates method, introduced by Verchery and Vong [2], is used to\ud
simplify the analysis. The strain-stress relation in polar coordinates, and the\ud
relationship between the compliance and the stiffness polar components are\ud
introduced. Using these relations, a system of six equations, having the elasticity\ud
coefficients (in polar) as unknown, is obtained. A classic tensile test method is used.\ud
A constant stress is applied to three samples cut in three different directions and the\ud
strains are measured (stress and strain are the inputs of the system). Four numerical\ud
examples are given showing the accuracy of the calculation. The problem is mainly\ud
the accuracy of the measurement. The interest in using four strain gages instead of\ud
three is studied as well as the consequence of an experimentation error on the strain\ud
state calculated. Finally, a program solving the system is presented as a tool for the\ud
experimental analysis
U-Kite development
Get PDFThe Following thesis describes the work which was undertaken in the conception, development, and the construction of an open sea towed vehicle used to deploy a wide range of oceanographic monitoring equipment. This streamlined submersible vehicle, is towed alongside a ship or small vessel, and remains slightly buoyant at all times, but once it is moving it uses its wings which are configured upside-down with respect to those on an aircraft to pull it down to depth and move it away from the towing vessels wake and wave system, while assuring lateral stability. The Preliminary design requirement called for a light, robust, stable, simple, and low cost platform able to operate in a close to rough sea surface, and can be worked from a relatively small vessels such as those used for surveys of estuaries and coastal. During the design phase of this project, tools such as parametric feature based solid modelling, computational fluid dynamics, and finite element analysis were employed to provide a solution to the problem. A prototype was built using CADCAM technology, and strong composite materials
A low cost free drifting position transmitter for the measurement of the thermocline properties
Get PDFThis thesis describes the work undertaken in the conception o f a vehicle able to observe the thermocline, the temperature and the salinity from the sea surface to 200m deep. This work includes the mechanical design of the device, termed a “ballast system” or “subsurface profiler” and the control of its velocity. This profiler is able to accommodate sensors capable of collecting such data (temperature and salinity). These sensors are provided by Sea-Sense Ltd, Galway. The profiler is designed to be disposable, auto-controlled and located by satellites in order to eliminate the recovery cost. It is designed to achieve at least two hundred cycles from the sea surface to 200m deep. Furthermore, the profiler velocity must be controlled accurately and as close as possible to O.OSm-s"1. Once the mechanical design and the selection of the appropriate sensors mounting components are achieved, the mechanical strength of the profiler, using appropriate materials, is evaluated at 200m deep where the pressure is relatively high (about 20 bars). The profiler velocity is simulated via a motor, which pumps (discharges) water in order to become heavier (lighter). Tools such as mechanical design automation software, finite element analysis and dynamical simulation systems software were employed to provide a solution to each problem through this project
Development of a semi-automatic self learning pattern recognition system for the control of electronic boards
Get PDFThis project was funded under the Applied Research Grants Scheme administered by Enterprise Ireland. The project was a partnership between Galway - Mayo Institute of Technology and an industrial company, Tyco/Mallinckrodt Galway. The project aimed to develop a semi - automatic, self - learning pattern recognition system capable of detecting defects on the printed circuits boards such as component vacancy, component misalignment, component orientation, component error, and component weld. The research was conducted in three directions: image acquisition, image filtering/recognition and software development. Image acquisition studied the process of forming and digitizing images and some fundamental aspects regarding the human visual perception. The importance of choosing the right camera and illumination system for a certain type of problem has been highlighted. Probably the most important step towards image recognition is image filtering, The filters are used to correct and enhance images in order to prepare them for recognition. Convolution, histogram equalisation, filters based on Boolean mathematics, noise reduction, edge detection, geometrical filters, cross-correlation filters and image compression are some examples of the filters that have been studied and successfully implemented in the software application. The software application developed during the research is customized in order to meet the requirements of the industrial partner. The application is able to analyze pictures, perform the filtering, build libraries, process images and generate log files. It incorporates most of the filters studied and together with the illumination system and the camera it provides a fully integrated framework able to analyze defects on printed circuit boards
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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