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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.
161

Design and implementation of robotic end-effectors for a prototype precision assembly system

Schöndorfer, Sebastian January 2016 (has links)
Manufacturers are facing increasing pressure to reduce the development costs and deployment times for automated assembly systems. This is especially true for a variety of precision mechatronic products. To meet new and changing market needs, the difficulties of integrating their systems must be significantly reduced. Since 1994, the Microdynamic Systems Laboratory at Carnegie Mellon University has been developing an automation framework, called Agile Assembly Architecture (AAA). Additionally to the concept, a prototype instantiation, in the form of a modular tabletop precision assembly system termed Minifactory, has been developed. The platform, provided by the Minifactory and AAA, is able to support and integrate various precision manufacturing processes. These are needed to assemble a large variety of small mechatronic products. In this thesis various enhancements for a second generation agent-based micro assembly system are designed, implemented, tested and improved. The project includes devising methods for tray feeding of precision high-value parts, micro fastening techniques and additional work on visual- and force-servoing. To help achieving these functions, modular and reconfigurable robot end-effectors for handling millimeter sized parts have been designed and built for the existing robotic agents. New concepts for robot end effectors to grasp and release tiny parts, including image processing and intelligent control software, were required and needed to be implemented in the prototype setup. These concepts need to distinguish themselves largely from traditional handling paradigms, in order to solve problems introduced by electrostatic and surface tension forces, that are dominant in manipulating parts that are millimeter and less in size. In order to have a modular system, the factory the main part of this project was the initialization and auto calibration of the different agents. The main focus, of this research, is on improving the design, deployment and reconfiguration capabilities of automated assembly systems for precision mechatronic products. This helps to shorten the development process as well as the assembly of factory systems.  A strategic application for this approach is the automated assembly of small sensors, actuators, medical devices and chip-scale atomic systems such as atomic clocks, magnetometers and gyroscopes.
162

Deposition and characterisation of nickel oxide based coatings for advanced glazing applications

McMeeking, Graham Donald January 1997 (has links)
This thesis is a comparative study of nickel oxide based thin films for use as a counter electrode in a variable transmittance electrochromic device. Coatings have been prepared using anodic electrodeposition, colloidal precipitation and radio frequency (r.f.) sputtering. Systematic studies of the effect of deposition process parameters on optical and electrochromic properties of such films have been undertaken. Optimum conditions for the deposition of coatings deposited by colloidal and anodic deposition have been determined. A novel process for the colloidal deposition of electrochromic a-Ni(OH)2 coatings using a simple one dip process is reported. Also the electrochromic properties of coatings anodically deposited from aqueous solutions containing NiS04 and NH40H were improved by the addition of the non-ionic surfactant polyoxyethylene sorbitan monolaurate. Spectroscopic and electrochemical analytical techniques were used to identify the chemical composition of the coloured and bleached states. It was found using Fourier transform infra-red spectrophotometry (FTIR) that coatings deposited by anodic and colloidal deposition contained f3-Ni(OH)2 and a-Ni(OH)2 respectively in the as-deposited and transparent states. For coatings deposited by both techniques 13 or y-NiOOH was detected in the coloured state using FTIR. Using Raman spectroscopy, y-NiOOH was detected in the coloured state for coatings deposited by anodic deposition from solutions containing the additive polyoxyethylene sorbitan monolaurate. I3-Ni(OH)2 was also detected in the transparent state of r.f. sputtered coatings that were electrochemically cycled in 1M KOH(aq). Using cyclic voltammetry the oxidation of nickel hydroxide to the oxyhydroxide was detected during colouration for coatings produced using anodic electrodeposition, colloidal precipitation and r.f. sputtering (after cycling sputtered films for 1 hour in 1M KOH(aq)). This information has been compared for films prepared using the different deposition techniques to enable the respective colouration mechanisms to be elucidated. Prototype electrochromic devices have been constructed and their performances assessed. It can be concluded that nickel oxide based coatings can be used as suitable counter electrodes for hydrated electrochromic devices.
163

Intelligent street lighting application for electric power distribution systems the business case for smartgrid technology

Davis, Wesley O'Brian Sr. January 1900 (has links)
Master of Science / Department of Electrical and Computer Engineering / Anil Pahwa / This research project builds upon previous work related to intelligent and energy efficient lighting in modern street and outdoor lighting systems. The concept of implementing modern smart grid technologies such as the proposed Street & Outdoor Lighting Intelligent Monitoring System (SOLIMS) is developed. A random sample of photocells from two municipal electric power systems is used to collect data of the actual on/off times of random photocells versus Civil Twilight (sunrise/sunset) times. A business case was developed using the data collected from the observations to support an electric utility company’s implementation of SOLIMS as an alternative to current operations. The goal of the business case is to demonstrate energy and capacity savings, reduced maintenance and operating costs, and lower carbon emissions.
164

How does changing technology affect students note-taking

Alsulmi, Badria January 1900 (has links)
Master of Science / Department of Mathematics / Andrew Bennett / In recent years, technology has improved and become a significant aspect in the classroom. Using technology has become a popular method of note-taking. This study investigates the effects of technology on note-taking by looking at the changes that can be shown between the traditional note-taking and taking notes by using different devices, such as the iPad and a smart pen. Modern technology, such as the smart pen which provides an automatic audio recording might improve student focus on important details. In addition, providing a standard note set along with note-taking tools such as an iPad might help student organize and access their notes. The result of this study showed that for all but one of the students, using technology did not affect their note-taking style or the amount of information in their notes. However, students were not satisfied with their notes when taken on the iPad.
165

Metropolitan comfort : biomimetic interpretation of hygroscopic botanical mechanisms into a smart textile for the management of physiological discomfort during urban travel

Kapsali, Veronika January 2009 (has links)
This project investigates the experience of physiological discomfort during travel through an urban environment such as London or New York in winter. The over and underground networks that lace a current metropolis, form vital passages that lead the traveller though a multitude of spaces each defined by unique temperature, humidity and activity level. It is impossible to predict possible eventualities and consequently accommodate in a selection of clothing to ensure physiological comfort. Modular clothing assemblies are currently employed for the management of physiological comfort to adjust the insulation and ventilation properties of a clothing system and rely on combinations of behavioural methods and textile properties. This method is compromised by factors such as limited availability of space and wearer’s ability to detect and respond to the onset of discomfort sensations. Current smart systems rely on temperature as a stimulus for actuation. Experimental work suggests that humidity is a more suitable trigger. Botanical mechanisms that employ hygroscopic expansion/contraction for seed and spore deployment were identified as paradigms for the development of a smart textile system. Biomimetic analysis of these natural mechanisms inspired the design of a textile prototype able to adapt its water vapour resistance in response to humidity changes in the microclimate of the clothing system. The resulting structure decreases its permeability to air by 20% gradually as relative humidity increases from 60% to 90%.
166

Distributed Adaptation Techniques for Connected Vehicles

Aygun, Bengi 03 August 2016 (has links)
"In this PhD dissertation, we propose distributed adaptation mechanisms for connected vehicles to deal with the connectivity challenges. To understand the system behavior of the solutions for connected vehicles, we first need to characterize the operational environment. Therefore, we devised a large scale fading model for various link types, including point-to-point vehicular communications and multi-hop connected vehicles. We explored two small scale fading models to define the characteristics of multi-hop connected vehicles. Taking our research into multi-hop connected vehicles one step further, we propose selective information relaying to avoid message congestion due to redundant messages received by the relay vehicle. Results show that the proposed mechanism reduces messaging load by up to 75% without sacrificing environmental awareness. Once we define the channel characteristics, we propose a distributed congestion control algorithm to solve the messaging overhead on the channels as the next research interest of this dissertation. We propose a combined transmit power and message rate adaptation for connected vehicles. The proposed algorithm increases the environmental awareness and achieves the application requirements by considering highly dynamic network characteristics. Both power and rate adaptation mechanisms are performed jointly to avoid one result affecting the other negatively. Results prove that the proposed algorithm can increase awareness by 20% while keeping the channel load and interference at almost the same level as well as improve the average message rate by 18%. As the last step of this dissertation, distributed cooperative dynamic spectrum access technique is proposed to solve the channel overhead and the limited resources issues. The adaptive energy detection threshold, which is used to decide whether the channel is busy, is optimized in this work by using a computationally efficient numerical approach. Each vehicle evaluates the available channels by voting on the information received from one-hop neighbors. An interdisciplinary approach referred to as entropy-based weighting is used for defining the neighbor credibility. Once the vehicle accesses the channel, we propose a decision mechanism for channel switching that is inspired by the optimal flower selection process employed by bumblebees foraging. Experimental results show that by using the proposed distributed cooperative spectrum sensing mechanism, spectrum detection error converges to zero."
167

Beläggningar -ett examensarbete i sammarbete med F.O.V Fabrics / Coatings : Thesis in collaboration with F.O.V Fabrics

OHLSSON, ANNIFRID, ENGSTRÖM, ELLINOR, LILJA, THERESA January 2010 (has links)
Bakgrund: F.O.V Fabrics har fått förfrågningar från sina kunder angående en beläggning som idag enbart finns pigmenterad. Kunder har efterfrågat en transparent variant av denna, vilken företaget nu vill undersöka möjligheterna för att förverkliga. Beläggningen skall bibehålla uppsatta kvalitetskrav. Syfte: Att försöka ta fram en transparent beläggning som bibehåller sina egenskaper gällande vattentäthet samt ånggenomsläpp. Metod: Laborationer har utförts både i liten och stor skala på Textilhögskolans färg- och beredningslabb. F.O.V har utifrån de småskaliga testerna, valt ut några prover, vilka vi tillsammans gått vidare med att testa storskaligt på Textilhögskolans labb. Kvalitetstester har sedan utförts på F.O.V. Huvudresultat: Som svar på vår problemformulering, har vi efter utförd undersökning, kommit fram till att vi, utifrån de givna parametrar vi tillhandahållit, inte går att få fram en transparent beläggning, vilken uppfyller de önskvärda kvalitetskraven.Ett viktigt resultat som dock framkommit av undersökningen var att om materialet bestryks med tillräcklig mängd pasta, räcker det med två lager, vilket är en stor kostnadsfördel gentemot trelagersbestrykning. / <p>In collaboration with F.O.V Fabrics, we have tried to develop a transparent coating for work wear, which is presented in this thesis.The testing of three new coating recipes, should maintain their properties in being water resistant and breathable. The shell material consisted of polyester, but since the content of classification is secret, we do not fully know how the fabric has been pre-prepared.Our small-scale tests and later on also the large-scale tests took place at the Swedish School of Textiles in Borås, where we also consulted our tutor Catrin Tammjärv and Jesper Carlsson from F.O.V Fabrics.We laborated with different parameters, and with both foam- and paste coatings. The final tests were further quality tested at F.O.V Fabrics. The results sometimes surprised us, as well as Jesper from F.O.V Fabrics. Our final results are to be followed in this thesis.</p><p>Program: Textil produktutveckling med entreprenörs- och affärsinriktning</p>
168

Textilen

JA HAN, JEANNINE January 2011 (has links)
II. ABSTRACTTextilen is a project designed to draw the human senses to the world of microand macro patterns in sound and color and to explore methods for correlating thetwo mediums. This goal is accomplished via a two-fold process. First of all, patternsin sound are explored through the use of textile materials by way of creating newinstrument interfaces, synthesizer sources, and tones in music harmony. Secondly,the patterns of the textiles themselves are explored and incorporated into costumesand characters so an association between the emanating sounds and the visualstimulus presented by the characters, highlights the underlying patterns used inboth mediums. The final presentation will be organized in the context ofperformance art in a controlled sound environment.A subsidiary aim of the project has been to develop myself as an artist and bringmy interests and inspirations into an artistic context. In order to execute this,a design method that incorporates practical and theoretical research alongsidetechnical invention, graphic design, sound experimentation, and characterdesign was chosen. / Program: Master in Textile Design
169

Literature over view of smart textiles

Henock, Dadi January 2011 (has links)
Civilization has brought tremendous changes in the life of human beings. All things are changing day by day through the efforts of scientific researches. Among these textiles are good examples. During the industrial revolution they showed up one step in their evolution. The changes would not stop on the manufacturing of textiles on machineries; however the advancements continued on the developments of synthetic and regenerated fibers, invention of synthetic dye stuffs and new finishing process like plasma and sol gel treatments. Since the last 20 years, the developments of new kinds of textiles called smart and inter reactive textiles emerged to the globe. Recently published Literatures, books and journals on the fields of textiles, electronics, information technology, advanced materials and polymers indicate that Smart textile materials and their application will boom in the near future. They are not dreams any longer. Two decades have elapsed since they become one part of the modern technology of clothing, being on the shelves of the apparel and fashion markets. They are everywhere; from geo textiles in the soil to the outer space in the expedition of the universe; from the hospitals beddings and clothing‘s to the entertainments; and from the personal healthcare to sportswear applications. This thesis work aims to make a look on the literature overview of these incredible, dynamic and very important objects. / Program: Magisterutbildning i textilteknologi
170

Towards a better understanding of SME responses to environmental regulatory pressures

Lynch-Wood, Gary January 2018 (has links)
The University of Manchester, PhD by Published Work, 2018 For several reasons, small and medium enterprises (SMEs) are an important group of firms. In most market economies SMEs contribute significantly to wealth and job creation, economic growth, and product and service innovation. At the same time, SMEs are said to produce environmental impacts that are significant and that need managing and regulating. Their importance, from an economic and environmental perspective, is reflected in the fact that SMEs have become an established subject for research, with a distinct area of analysis focusing on how they manage their environmental impacts. Despite considerable interest in this area, aspects of their behaviour are in need of further examination, for there are still misunderstandings and gaps in knowledge. An area where gaps exist is how SMEs respond to different forms of environmental regulation (e.g., command-based or market-based approaches) and different forms of regulatory pressure (e.g., such as those pressures from civil society that might induce compliance-related activities or market forces that might flow through, and affect, the value chain). Why the gaps? On the one hand, and generally speaking, a common claim among those who have considered issues affecting smaller firms is that regulation is an important driver of environmental behaviour. There is a well-documented set of linked claims and empirical findings that smaller firms tend to be motivated by compliance with regulatory standards, yet owing to their scarce resources can find themselves hovering on the edge of compliance. Typically, SMEs will attempt to do no more than the law requires of them. They tend not, as it were, to go beyond compliance. Of course, this is an important observation - one that might say much, even if indirectly, about the motivations and intentions of smaller firms. It might indicate that SMEs, rather than addressing environmental issues, are more concerned with making cost savings and efficiency gains, or with satisfying the requirements of customers over such matters as product or service quality and delivery. While significant, there are at least three reasons why this view remains incomplete as an explanation for the interaction between SMEs, regulation and the environment. Firstly, this view tends to over-homogenise smaller firms. By treating them as a standardized group, the inference is that SMEs view and respond to regulation - i.e., they are all driven by regulation - in a broadly similar way. Secondly, it says little about how and why regulation drives behaviour. Claiming that regulation drives behaviour is helpful, but the claim is unduly narrow and leaves several important questions. In what ways does regulation drive behaviour? Does regulation drive all smaller firms in the same way? Thirdly, and finally, it suggests that different forms of regulation drive SME behaviour and that different forms of regulation drive this behaviour in broadly similar ways. That is, it is incomplete as it lacks appreciation of the widening scope of regulation and governance, and the nature of smart mixes of regulation. It fails to properly consider whether and how SMEs might respond differently to command-based regulation, market- or information-based measures, or self- or so-called civil regulatory pressures. On the other hand, and again in general terms, while those who have examined regulation have looked at how it can influence firms, they have tended to pay too little regard to how firms of different size may respond to different approaches or to how the factors and characteristics relating to size may shape the effectiveness of regulation. SMEs particularly are often discussed as an unusual sideshow that might raise different issues in relation, say, to the impacts of regulation on performance or innovation. That we often pay too little regard to how firms of different size may respond raises difficulties, particularly given our increasing understanding that there is no guarantee that a particular instrument will work in all situations. In other words, we are becoming more aware of the fact that the effectiveness or ineffectiveness of regulation is likely to be context-sensitive, and that the size of the enterprise is likely to be an important determinant of context. This thesis does take, and provides evidence for, the view that the organisational context is crucial to understanding how regulation functions. The thesis does not claim to provide all answers, but it does adopt the position that, in aggregate terms, a firm's size, or the factors that can be associated with size (e.g., resources, skills, knowledge, visibility, profile, stakeholder relations), and related factors concerning a firm's mind-set, can affect two things; first, the types of regulatory influences that may affect organizational behaviour and, second, how firms will respond to those influences. By focusing on SMEs, the thesis in some ways reinforces the dominant view that regulation is a driver of behaviour. Nevertheless, it goes much farther than this by showing, both theoretically and empirically, that there are important differences across SMEs and that these differences determine how and why they respond to regulation. It extends the common view by showing how SMEs differ not only in terms of the types of regulatory influences that shape their behaviour, but also in terms of how they react to these different influences. The emerging picture thus shows that the responses of firms are determined by their particular characteristics. The term used in this thesis is 'receptive capacity', which is shown to be a composite measure that includes the capabilities (e.g., resources, skills, knowledge) and orientations (e.g., views) of firms. It is suggested here that the range of receptive capacities across firms is enormous, since no two firms will be identical. Yet, it is argued - and demonstrated - that firms can be grouped according to certain identifiable characteristics, and that these groups of firms will respond to regulatory pressures in broadly similar ways; that is, there are groups of firms that have broadly similar resources and broadly similar worldviews. Thus, as well as suggesting that differences can be found at the micro level, it is demonstrated that there are sufficient commonalities across some firms that we can understand them as groups - groups of individual firms with some common characteristics. In conclusion, it is the differences across firms that provide us with a more sophisticated view of how SMEs are influenced by, and respond to, regulation. It is the nature of differences that is the main contribution of this research to both the fields of regulation and organisational and management studies. It is suggested finally that these differences have implications for how we design regulation, for how we may expect regulation to work or indeed not work, and for issues such as regulatory complexity and smart mixes.

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