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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.
101

Solder paste inspection based on phase shift profilometry

Hui, Tak-wai., 許德唯. January 2007 (has links)
published_or_final_version / abstract / Electrical and Electronic Engineering / Master / Master of Philosophy
102

Automated radiographic inspection of through-hole electronic circuit board solder defects

Leal, James Andrew, 1963- January 1988 (has links)
A study has been carried out to investigate the use of "real-time" radiography as a method of automated inspection of through-hole electronic circuit board solder joints. By evaluating five major solder defects it has been found that film radiography employing high contrast film results in a definite distinction between a good solder joint and a defective solder joint. The same five defects were also found to be distinguishable from a good solder joint when evaluated by a real-time radiographic inspection unit using digital image processing. Although the type of defect being investigated was not discernible, the ability to distinguish a good solder joint from a defective solder joint is a major step in the implementation of automated solder joint inspection for military electronics.
103

Measurement of Surface Defects in 3D Printed Models

Shanmugham Chetiyar, Krishna Kumar, Galla Venkata Sri, Sai Sumanth January 2016 (has links)
The ease of manufacturing using additive manufacturing (3D-Printing) reduces the overall production cost compared with the traditional manufacturing techniques. Because of the benefits of 3D printing technologies, it is proposed to be used in manufacturing of different products. But there are some flaws that are causing significant effect on 3D printed models which degrades the quality of the product. Hence in order to handle these defects, different measurement techniques are needed to quantify the defects that are seen on the surface of 3D-printed models. In our study there are two experimental setups. Experimental setup one was made to find out the proper coating timing to enable measurement using two good samples without defects in different colors blue and red with same material. Different 2D and 3D parameters were used for the surface measurements are collected and noted for further research. The Defective samples are measured using the state of the art equipment at Halmstad University. Experimental setup two was made to prepare the defective samples and measure the samples. The results obtained assisted to quantify the surface defects seen in the samples. This thesis studies some of the different methods that can be implemented to measure the surface defects on the 3D printed models. A little study on the various defects formed on the 3D printed models and what are the causes for the defects on the products were performed. The results suggest different method for the defects to be measured in both industrial and home or small scale office applications.
104

Printed Matter, Inc., The First Decade: 1976-1986

Dixon, Claire 29 November 2010 (has links)
This thesis provides an account of the events of the first ten years of Printed Matter, Inc., a distribution center for artists’ books established in New York City in 1976. Included are descriptions of the individuals who formed Printed Matter’s first board, their objectives, books published by Printed Matter, and the windows installation program. This thesis also describes challenges the board members faced, including lack of organization, difficulty cultivating a broad public audience, and inadequate income. In addition, it recounts the gradual streamlining of business practices, and the realignment of goals and expectations for the genre as board members accepted the fact of a limited audience for artists’ books. The conclusion offers a brief summary and a look at Printed Matter, Inc.’s current operations.
105

System integration of electronic functionality in packaging application

Unander, Tomas January 2011 (has links)
Sensor applications are becoming increasingly important as products are now being requested to be more and more intelligent and safe. As the costs involved in sensor technology decrease its usage will spread to new market segments including new areas with products that have never previously used such functionalities, including, wood fibre based products for packaging, hygiene or graphical use. Currently there is a significant interest in developing technology that will allow packages to become interactive and be integrated with digital services accessible on the Internet. In this thesis, the system integration of a hybrid RFID based sensor platform is presented. This proposed platform provides a trade-off between the communication performance and its compatibility with international standards and also includes flexibility in on‐package customization, including the type and number of sensors. In addition it combines the use of traditional silicon based electronics with printed electronics directly onto wood fibre based materials so as to enable the possibility of creating smart packages. Together with the system integration of the sensor platform, five printed moisture sensor concepts that are designed to work with the sensor platform are presented and characterized. Firstly, there is a moisture sensor that shows a good correlation to the moisture content of wood fibre based substrates. The second one involves a sensor that detects high relative humidity levels in the air and the third is an action activated energy cell that provides power when activated by moisture. The fourth one deals with two types of moisture sensors that utilize silver nano-particles in order to measure the relative humidity in the air. The final one is a printable touch sensitive sensor that is sensitive to the moisture contained in the hand. A concept of remote moisture sensing that utilizes ordinary low cost RFID tags has also been presented and characterized. The main focus is thus on system integration to, by combining silicon based electronics with printed electronics, find the most low cost solution with regards to flexibility, sensor functions and still meet the communication standards. / När efterfrågan på mer intelligenta och säkra produkter ökar så ökar även intresset för olika typer av sensorer. När kostnaden för dessa sensorer sjunker så kommer användandet av dessa att utökas till nya marknadssegment som tidigare inte använt denna typ av funktionalitet, som tillexempel pappersbaserade förpackningar, hygienartiklar och papper för grafiskttryck. Det är för närvarande ett stort intresse att utveckla tekniker som tillåter förpackningar att bli interaktiva och integrerade med olika digitala tjänster kopplade till Internet. I denna avhandling så presenteras systemintegrationen av en RFID baserad sensor plattform som tillhandahåller en avvägning mellan kommunikationsprestanda, kompabilitet med internationella standarder och kundanpassningsflexibilitet. Där man direkt på förpackningen kombinerar fördelarna med traditionell kiselbaserad elektronik med trycktelektronik för att kunna skapa intelligenta förpackningar. I avhandlingen presenteras och utvärderas även fem trycka fuktsensorer som är designade att kunna användas tillsammans med sensor plattformen. Den första sensorn mäter fukthalten i cellulosabaserade substrat. Den andra kan detektera höga fukthalter i luften. Den tredje, som aktiveras vid en händelse, producerar en elektrisk ström när den blir fuktig. Den fjärde sensorn använder sig av silverbaserade partiklar i nanostorlek för att mäta fukthalten i luften. Den femte sensorn är en beröringskänslig sensor som ger utslag av fukten i handen. Utöver dessa sensorer så utvärderas även ett koncept med en fuktsensor som kan läsas av på avstånd. Fokus är således att på system integrationsnivå, med hjälp av att kombinera kisel elektronik med tryckt elektronik, hitta den mest kostnadseffektiva lösningen med avseende på flexibilitet, sensor funktionalitet och att även kunna möta kommunikationsstandarderna.
106

Recuperação de níquel a partir do licor de lixiviação de placas de circuito impresso de telefones celulares. / Recovery of nickel from leach liquor of printed circuit boards of mobile. Phones

Murcia Santanilla, Adriana Johanny 05 December 2011 (has links)
Os resíduos de equipamentos elétricos e eletrônicos é um dos fluxos de resíduos que mais cresce no mundo. O aumento na produção destes equipamentos como resultado dos avanços tecnológicos e a sua rápida obsolescência promovem o aumento de geração deste tipo de resíduos. Portanto, este trabalho tem como objetivo estudar a recuperação de níquel presente no licor de lixiviação de placas de circuito impresso de telefones celulares obsoletos, através da aplicação de processos hidrometalúrgicos e eletrometalúrgico. Inicialmente, foram preparadas soluções sintéticas a partir da composição química do licor de lixiviação das frações magnética (MA) e não magnética (NMA) das placas de circuito impresso cominuídas. Os elementos presentes nas soluções são: ferro, zinco, níquel e alumínio. Posteriormente, foi realizada uma etapa de remoção do ferro, através de precipitação seletiva. A morfologia e a composição química do precipitado foram analisadas através de Microscopia Eletrônica de Varredura (MEV) e EDS, respectivamente. A composição química das soluções resultantes da precipitação foi determinada através da técnica de espectrofotometria de absorção atômica. Através do processo de precipitação conseguiu-se uma porcentagem de remoção de ferro na solução NMA de 99,6% e na solução MA de 99,9%, porém, observou-se também a coprecipitação de zinco, alumínio e níquel. Com as soluções resultantes desta etapa, foi realizada a purificação das soluções através de extração por solvente, utilizando Cyanex 272 como agente extratante. As variáveis estudadas nos ensaios de extração por solvente foram: pH, concentração do extratante, relação fase aquosa/orgânica (A/O) e temperatura. . Além disso, também foi determinado o número de contatos necessários para a extração de ferro, zinco e alumínio, obtendo assim, uma solução aquosa contendo unicamente níquel. Finalmente, foram realizados os ensaios de eletrodeposição para a obtenção de níquel metálico. Foi avaliado o efeito da temperatura sobre o filme depositado. A morfologia dos depósitos e a espessura da camada foram analisadas através do MEV, verificando que o aumento da temperatura influencia nas características do depósito obtido. / Electric and electronic waste (e-waste) is one of the fastest growing waste streams in the world. Continuous increasing production owing to the technological advances and the products consumption rise, all together with the rapid obsolescence of this scrap promotes the necessity of exchange and the increasing of generate waste. Therefore, the aim of this work is to study a recovering of nickel from leach liquor of cell phones printed circuit boards, through of hydrometallurgical and electrometallurgical process application. Firstly, was prepared synthetic solutions of both magnetic (MA) and nonmagnetic (NMA) fractions of printed circuit boards. The metal ions present in the synthetic solutions are: iron, zinc, nickel and aluminium. Afterwards was realized the iron removal stage, through both selective precipitation and solvent extraction process, in order to make a comparison of these techniques. The precipitates were analyzed across of scanning electron microscope (SEM), and the chemical composition of these solutions through atomic absorption spectrometry (AAS). With selective precipitation it was obtained 99,6% and 99,9% of iron removal with selective precipitation in NMA and MA solutions, respectively. Therefore, it was also observed co-precipitation of zinc, aluminium and nickel. With solutions after precipitation stage was carried out the solutions purification through solvent extraction using cyanex 272 as extractant. Solvent extraction test were studied different parameters, such as: equilibrium pH, extractant concentration, aqueous-organic (A/O) ratio and temperature. It was also determinates the stages number required for iron, zinc and aluminium extraction, to obtain nickel in aqueous solution uniquely. Finally, was carried out the electrodeposition test for obtain metallic nickel. Was analyzed the effect of temperature on the deposited layer. Surface Morphology and thickness of the deposits were evaluated by MEV, verifying that temperature increasing influences on deposited layer.
107

Recuperação de metais a partir do processamento mecânico e hidrometalúrgico de placas de circuito impresso de celulares obsoletos. / Metals recovery from mechanical and hydrometalurgy processing of printed circuit boards from obsolete mobile.

Moraes, Viviane Tavares de 22 December 2010 (has links)
O avanço da tecnologia de aparelhos eletro-eletrônicos favorece a troca constante dos equipamentos. O freqüente descarte de aparelhos obsoletos se torna um problema de sustentabilidade e também um problema ambiental devido ao seu acúmulo em aterros. A solução para minimizar estes impactos é a reciclagem de seus componentes. Por esta razão, o principal objetivo deste trabalho é estudar o processamento das placas de circuito impresso de telefones celulares através de operações unitárias de Tratamento de Minérios e hidrometalurgia a fim de se recuperar o cobre contido nas placas. Para isso, inicialmente, placas de circuito impresso foram processadas em moinho de martelos, a fim de liberar os materiais, em seguida foi feita a separação magnética do material cominuído. Com a fração não magnética foi feita a separação eletrostática e o material foi separado em: fração condutora, mista e não condutora, com cada fração foi feita a classificação granulométrica e, posteriormente, realizaram-se ensaios de caracterização como pirólise, digestão em água régia e análise química de espectroscopia de emissão óptica por indução de plasma. Os processos hidrometalúrgico aplicados para a recuperação de cobre nas placas de circuito impresso de aparelhos celulares obsoletos envolvem etapas lixiviação com ácido sulfúrico na ausência e na presença de peróxido de hidrogênio. Os resultados da caracterização mostraram que as placas de circuito impresso de celulares após a moagem possuem 24% de cerâmicas; 12,7% de polímeros e 63,3% de metais. Além disso, após a classificação granulométrica e a separação eletrostática os materiais não se concentraram em nenhuma fração especifica, portanto o processamento mecânico visando a recuperação de metais deve contemplar a moagem e a separação magnética. / The technology advancement of electro-electronics devices favors the constant equipment exchange. The frequent disposal of obsolete equipment becomes a sustainability problem and also an environmental problem due to their accumulation in landfills. One possible solution to minimize these impacts is the recycling of their components. For this reason the aim goal of this study is processing of printed circuit boards of mobile phones utilizing unit operation of ore treatment and hydrometallurgy to recover the copper contained in the printed. Therefore, initially printed circuit boards were processed on a hammer mill to release the materials, then it was made magnetic separation of comminuted material. With the non-magnetic fraction was made electrostatic separation in which the material was separated into: conductive, mixed and non-conductive fraction, with each fraction was made grain sized classification and then assays were performed analysis of characterize as pyrolysis, digestion in aqua regia and chemical analysis of inductively coupled plasma atomic emission spectroscopy. Hydrometallurgical processes applied to the cooper recovery in printed circuit boards of obsolete mobile phones, involve steps leaching with sulfuric acid in the absence and presence of hydrogen peroxide. The characterization results showed that the printed circuit boards of mobile phones after grinding have ceramics 24%, polymers 12.7% and metals 63.3%. Moreover, after grain sized classification and electrostatic separation the materials didn\'t concentrate in no specific fraction, therefore the mechanical processing in order to recover metals should include grinding and magnetic separation.
108

Development of a PCB-integrated micro power generator.

January 2001 (has links)
Ching Ngai-hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 81-83). / Abstracts in English and Chinese. / Chapter CHAPTER 1 ´ؤ --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background on Micro Power Supply --- p.1 / Chapter 1.2 --- Literature Survey --- p.3 / Chapter 1.2.1 --- Comparison Among Different Power Sources & Transduction Mechanisms --- p.3 / Chapter 1.2.2 --- Previous Works in Vibration Based Generator --- p.6 / Chapter CHAPTER 2 一 --- DESIGN OF THE MICRO-POWER GENERATOR --- p.8 / Chapter 2.1 --- Concept of Power Generation --- p.8 / Chapter 2.2 --- Design Objectives of the Micro Power Generation --- p.9 / Chapter 2.3 --- System Modelling and Configuration of the Generator --- p.10 / Chapter 2.4 --- RESONATING STRUCTURE --- p.13 / Chapter 2.4.1 --- Material Selection --- p.13 / Chapter 2.4.2 --- Fabrication Method --- p.14 / Chapter CHAPTER 3 一 --- INDUCTING STRUCTURE --- p.17 / Chapter 3.1 --- Selection of Winding Method --- p.17 / Chapter 3.2 --- Solenoid Windings --- p.19 / Chapter 3.2.1 --- Fabrication Process --- p.19 / Chapter 3.3 --- PCB Windings --- p.20 / Chapter 3.3.1 --- Fabrication Process of the Prototype of Six-layer PCB --- p.21 / Chapter CHAPTER 4 一 --- EXPERIMENTAL RESULTS --- p.27 / Chapter 4.1 --- Experimental Setup --- p.27 / Chapter 4.1.1 --- Generator Systems --- p.27 / Chapter 4.1.2 --- Measurement of Vibration and Output from the Generator --- p.28 / Chapter 4.1.3 --- Observations of Vibration Motions --- p.31 / Chapter 4.2 --- SPRING FOR THE MICRO GENERATOR --- p.32 / Chapter 4.2.1 --- Spring Micromachining Optimization --- p.32 / Chapter 4.2.2 --- Mode Shapes and Spiral-spring Structures --- p.35 / Chapter 4.3 --- MAGNET FOR THE MICRO GENEARTOR --- p.37 / Chapter 4.3.1 --- Generator Output and Magnetic Dipole Orientation --- p.37 / Chapter 4.4 --- HAND-WIRED COIL GENEARTOR --- p.45 / Chapter 4.4.1 --- Performance of Different Design of Housings --- p.45 / Chapter 4.5 --- PCB COIL GENERATOR --- p.48 / Chapter 4.5.1 --- Size of PCB Coils vs. Generator Output --- p.48 / Chapter 4.5.2 --- Effect of Number of PCB Layers --- p.54 / Chapter 4.5.3 --- Array of Generators --- p.61 / Chapter CHAPTER 5 一 --- MODELLING AND COMPUTER SIMULATION --- p.63 / Chapter 5.1 --- Modelling the Second-Order System --- p.63 / Chapter CHAPTER 6 一 --- APPLICATION DEMONSTRATIONS --- p.69 / Chapter 6.1 --- INFRARED SIGNAL TRANSMISSION --- p.69 / Chapter 6.2 --- RF WIRELESS TEMPERATURE SENSING SYSTEM --- p.70 / Chapter CHAPTER 7 ´ؤ --- CONCLUSION --- p.75 / Chapter CHAPTER 8 一 --- FUTURE WORK --- p.77 / BIBLIOGRAPHY --- p.81 / APPENDIX --- p.84
109

A critical edition of Luis Velez Guevara's 'Los hijos de la Barbuda'

Monahan, Caroline January 1974 (has links)
The earliest-known printed version of 'Los hijos de la Barbuda', which is that found in the Tercera parte de las comedias de Lope de Vega y otros autores (Barcelona 1612) t provides the copy-text for this critical edition. Obvious errors have been corrected, but the original spelling has been preserved, the punctuation altered as little as possible, and the copy-text's method of capitalisation and accentuation has been retained. The play is preceded by an introduction which includes a description of all known versions of the text of Los hijos de la Barbuda, a chapter on the transmission of the text., one on the date of composition and performances, and chapters on staging, theme and presentation, language, and versification. Four sets of notes follow the text of the play: textual notes showing substantive departures in the present edition from the copy-text, a list of emendations of accidentals, a collation of the early texts, and a set of notes elucidating the text. Extra lines and scenes appearing in the seventeenth and eighteenth-century manuscripts are included in an appendix.
110

The preservation and conservation of ink jet and electrophotographic printed materials

Glynn, Deborah January 2001 (has links)
This research project has investigated the light fastness of ink jet and electrophotographic printed materials by the means of an extensive accelerated and natural ageing test programme. The effect of visible radiation of different wavebands on the deterioration of a selection of ink jet printed materials has also been assessed. The findings of the research indicate that all of the ink jet printed materials tested are sensitive to light and should not therefore, be put on permanent display. Most of the ink jet printed samples exhibited greater light sensitivity to the shorter wavelengths of the visible spectrum, than the longer wavelengths, with damage decreasing as wavelength increases. This relationship was not evident with the cyan and blue printed samples, which showed that their light sensitivity was determined by the spectral absorption characteristics of the printed patch. Some of the ink jet printed materials produced erratic fading rates on exposure to light. This phenomenon was attributed to either the occurrence of photochromism or the disintegration of the dye particles in the ink, but further testing needs to be conducted to gain a better understanding of this reaction. Other factors also influenced the light fastness of the ink jet materials, such as the type of paper employed for printing, ink concentration and ink combination. The electrophotographic printed materials were found to be more stable to light, although the yellow toner from some of the systems would show noticeable fading after approximately 65 to 325 years on permanent display (at 50 lux for eight hours per day). A range of basic conservation treatments was also been investigated and the results indicated that ink jet print materials are very sensitive to all forms of aqueous treatments. Finally, thermal/dark ageing has been performed on the digital printed papers employed in this investigation. The conclusion is that all of the papers are prone to yellowing in storage.

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