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Thermal management of heat sensitive components in Pb-free assemblyRaut, Rahul. January 2005 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Department of Systems Science & Industrial Engineering, 2005. / Includes bibliographical references.
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A systematic approach for selection of best PB-free printed circuit board (PCB) surface finishSubbarayan, Guhan. January 2007 (has links)
Thesis (Ph. D.)--State University of New York at Binghamton, Department of Systems Science and Industrial Engineering, 2007. / Includes bibliographical references (leaves 203-208).
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Potential of nanocellulose for conductive ink preparation / Utilisation des nanocelluloses pour la préparation d'encres conductricesHoeng, Fanny 14 October 2016 (has links)
Ce projet vise à développer de nouvelles encres à base de nanofils d’argent et de nanocellulose pour des applications conductrices et transparentes. Les nanocelluloses, nanoparticules issues de la cellulose, sont de deux types : les nanocristaux de cellulose (NCC) et les nanofibrilles de cellulose (NFC) et possèdent des propriétés bien spécifiques. Ce travail a consisté d’une part (i) à utiliser la forme tubulaire et rigide des NCC pour produire des nanotubes d’argents par synthèse chimique, avant leur formulation en encre et d’autre part (ii) à utiliser les propriétés d’enchevêtrement des NFC flexibles pour stabiliser des nanofils d’argent commerciaux, habituellement instables en suspension. Les divers résultats de ce projet ont permis d’aboutir à la formulation brevetée et à la commercialisation d’une encre conductrice à base d’une faible quantité d’argent et de NCC et de deux encres conductrices et transparentes à base de NFC et de nanofils d’argent. Les interactions physico-chimiques et la stabilité colloïdale de ces suspensions hybrides ont été étudiée de manière fondamentale, tout en développant des formulations adaptées à divers procédés d’impression, que ce soit à échelle laboratoire mais aussi industrielle. / This project aims at developing new conductive inks based on nanocellulose and silver nanowires for transparent and conductive applications. Nanocellulose are nanoparticles extracted from the cellulose and two kinds currently exist: the cellulose nanocrystals (CNC) and the cellulose nanofibrils (CNF). This project have evaluated on one hand the ability of using tubular rigid CNC as template for producing silver nanorods, prior their formulation into conductive inks. On the other hand, the ability of using flexible and entangled CNF to stabilize commercial silver nanowires, usually unstable in suspension, was investigated. The results of this project lead to the patented formulation and commercialization of one low silver content conductive ink based on silver and CNC and two conductive transparent ink based on CNF and silver nanowires. Physico-chemical interactions and colloidal stability of such hybrid suspension have been scientifically studied meanwhile printing process adapted formulation have been successfully designed and tested at laboratory scale but also industrial scale.
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Desenvolvimento de biossensor baseado em tirosinase para determinação de adenosinaMedeiros, Natália Goedtel January 2017 (has links)
Neste trabalho relata-se pela primeira vez a determinação de adenosina por um biossensor baseado em tirosinase. O biossensor foi desenvolvido mediante a modificação de um eletrodo de carbono impresso (SPE) com nanopartículas de ouro (AuNPs), tirosinase (Tyr) e Nafion, denominado biossensor Nafion/Tyr/AuNPs/SPE. As AuNPs sintetizadas possuem diâmetro médio de 15,0 ± 1,1 nm e sua função é melhorar a via de condução de elétrons entre a enzima e o eletrodo. Utilizou-se o aprisionamento com filme Nafion® para evitar a lixiviação enzimática da superfície do eletrodo. A tirosinase imobilizada apresentou boa atividade frente ao substrato catecol. Verificou-se que a adenosina atua como um inibidor do tipo não-competitivo. O biossensor é estável durante pelo menos 45 dias. Além disso, foi realizada a eletro-oxidação da adenosina para sua determinação. O biossensor apresenta sensibilidade superior em comparação com SPE, AuNPs/SPE e Nafion/AuNPs/SPE. As curvas de calibração revelaram duas faixas lineares para as concentrações de adenosina, de 1,0 × 10-5 mol L-1 até 5,0 × 10-5 mol L-1 e entre 6,0 × 10-5 mol L-1 e 1,2 × 10-4 mol L -1. O limite de detecção (3 × (desvio padrão + média dos brancos)/coeficiente angular da curva) foi de 7,0 × 10-7 mol L-1. / In this work we report for the first time the determination of adenosine by a biosensor based on tyrosinase. The biosensor was developed by modifying a screen-printed carbon electrode (SPE) with gold nanoparticles (AuNPs), tyrosinase (Tyr) and Nafion, denoted as Nafion/Tyr/AuNPs/SPE biosensor. The synthesized AuNPs have a mean diameter of 15.0 ± 1.1 nm and their function is to improve the electron conduction pathway between the enzyme and the electrode. The entrapment with Nafion® film was selected to prevent the enzyme lixiviation from the electrode surface. Immobilized tyrosinase showed good activity with the catechol substrate. It was found that adenosine acts as a non-competitive type inhibitor. The biosensor is stable for at least 45 days. In addition, the electro-oxidation of adenosine was performed for its determination. The biosensor has superior sensitivity compared to SPE, AuNPs/SPE and Nafion/AuNPs/SPE. Calibration curves revealed two linear ranges for adenosine concentrations of 1,010-5 mol L-1 up to 5,010-5 mol L-1 and from 6,010-5 mol L-1 to 1,210-4 mol L-1. The detection limit (3 × (standard deviation + mean of blanks)/slope of the curve) was 7,010-7 mol L-1.
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Produção de pó de cobre eletrolítico a partir de resíduos de placas de circuito impressoOcampo, Edwin José Figueroa January 2017 (has links)
As placas de circuito impresso (PCI) estão presentes em quase todos os equipamentos eletroeletrônicos (EEE) e são componentes fundamentais dos computadores. Estes dispositivos são compostos de polímeros, cerâmicos e metais, sendo que nestes últimos encontra-se uma fração significativa de metais valiosos tais como ouro, prata e cobre. A mistura heterogênea dos referidos materiais torna sua reciclagem complexa, de forma que, tecnologias têm sido desenvolvidas e aprimoradas para a reciclagem das PCI. Esta pesquisa apresenta uma rota alternativa para recuperação do cobre contido nas PCI estudadas. Inicialmente, realizou-se um processamento mecânico constituído de fragmentação e moagem, classificação granulométrica e separação magnética, visando à liberação dos metais contidos nas placas e, principalmente, à concentração metálica do cobre. Esta rota não inclui a clássica separação eletrostática para a recuperação metálica. Foram realizadas duas lixiviações ácidas com ácido sulfúrico; a primeira para a remoção de elementos indesejados (Fe, Ni ,Zn, Al) e, a seguir, uma segunda lixiviação ácida, em meio oxidante, para obtenção de um eletrólito concentrado de íons cobre. A solução eletrolítica produzida na segunda lixiviação foi submetida à eletrodeposição, obtendo-se cobre na forma de pó para a sua utilização em processos da metalurgia do pó, como matéria prima para a indústria de componentes mecânicos e científicos sinterizados. Os resultados indicaram que é possível a recuperação do cobre presente nas PCI provenientes de REEE. O pó de cobre obtido atende adequadamente a requisitos técnicos necessários para sua aplicabilidade nos processos de metalurgia do pó, como por exemplo: estrutura dendrítica, composição química apropriada e distribuição granulométrica das partículas, atingindo o objetivo geral desta pesquisa. / The printed circuit boards are found in almost all electrical electronic equipments (EEE) and are essential components of computers. The PCBs consist of polymers, ceramics and metals, and among the metals, there is a significant fraction of valuable metals such as gold, silver and copper. The heterogeneous mixture of these materials makes their recycling difficult. Therefore, many kinds of technologies have been developed and improved for the recycling of these electronic components. This scientific research proposes an alternative route for recovery of copper contained in the analyzed PCB. Initially, a mechanical process consisting of fragmentation and grinding, size classification and magnetic separation was performed, aiming the liberation of metals from the boards, especially the concentration of copper. This route does not include the classical electrostatic separation for metal recovery. Two acid leaching procedures were performed with sulfuric acid: the first one for removing the unwanted elements (Fe, Ni, Zn, AL), followed by a second acid leaching, in an oxidizing medium, to obtain a concentrated copper ion electrolyte. The electrolytic solution produced in the second leaching was submitted to electrodeposition obtaining copper powder, which is used in powder metallurgy processes as raw material for the industry of sintered mechanical and scientific components. The results indicate that the recovery of metals contained in PCB originated from WEEE is possible. The obtained copper powder adequately meets the technical requirements for its applicability in powder metallurgy processes, such as: dendritic structure, appropriate chemical composition and particle size distribution, reaching the general objective of this research.
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Thermoelectric energy harvesting in displaysTsangarides, Constantinos January 2017 (has links)
The development of a complete thermoelectric generator and its application on a display polarizer film was successfully accomplished in this thesis. A systematic study of the prospective thermoelectric materials, PEDOT:PSS-based and ${ZnON}$, used for the present application is presented. To the best of our knowledge, this is the first exploration of the thermoelectric parameters of ${ZnON}$ reported here. Thin-film deposition of these materials was performed via both solution- and vacuum-based techniques. In addition, certain doping mechanisms were tested in an attempt to further understand the correlation between electrical conductivity and Seebeck coefficient. A maximum power factor of $42{\mu}Wm^{-1}K^{-2}$ was achieved for the PEDOT:PSS-based thin film at room temperature. It was initially doped via 5vol% of DMSO and sequentially treated with ethylene glycol. Specifically, its electrical conductivity displayed a 2-fold increase after EG treatment, reaching a value of about 1632 Scm$^{-1}$. Systematic studies performed on the association between thin-film thickness and its Seebeck coefficient shows a decrease in the latter as the number of multilayers printed increases. Among the different $O_{2}/N_{2}$ ratios that were tested for ${ZnON}$ thin films, a maximum power factor value of 163${\mu}Wm^{-1}K{-2}$ was achieved with the lowest $O_{2}$ flow rate configuration. In contrast to PEDOT:PSS-based thin films, the ${ZnON}$ displayed the opposite effect on the relation of the Seebeck coefficient with respect to thin-film thickness. Furthermore, a heterostructure was also developed by implementing ${ZnO}$ nanowires into the ${ZnON}$ thin film. ${ZnO}$ nanowires have been fabricated through the hydrothermal method on inkjet-printed patterns of zinc acetate dihydrate. It has been demonstrated that with the right inkjet-printing parameters and substrate temperature, ${ZnO}$ nanowires can be effortlessly fabricated in accordance with the desired pattern variations under low temperature and mild conditions. Finally, a complete device of the thermoelectric generator was fabricated using the above materials and a special set-up developed in order to test the device on the polarizer. The power output achieved from a 1-thermoelectric couple under normal backlight illumination and ambient conditions was 23pW. Overall, it is thought that the particular design and proof of concept presented here can be the basis of a prospective energy harvesting scheme via thermoelectrics in future display-based handheld devices.
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Automated characterization of printed electronicsMagnusson, Elias, Svensson, Samuel January 2018 (has links)
This thesis was conducted to provide an automated method for characterization of printed electronics. The work was built on a multi-axis milling machine. Further, the machine was modified by replacing the milling-tool with an installment utilizing electrical probing. Different measurement techniques, machine vision applications, and software solutions were evaluated and utilized. All the revolving functionalities of this project was then merged into a complete system, controlled by a graphical user interface. The resulting system was capable of autonomously characterize a given number of components on a printed sheet. The final version of the system is capable of finding the origin of the sheet by using machine vision and fiducial markers.
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Investigation of the curing process of an epoxy/silica composite for microelectronics / Etude du procédé de réticulation d'un composite époxy/silice pour les applications en microélectroniqueGranado, Lérys 17 November 2017 (has links)
En raison de la demande de miniaturisation croissante dans l’industrie microélectronique, il est nécessaire de développer des circuits imprimés multicouches (PCB, Printed Circuit Board) présentant une densité d’interconnections de plus en plus élevée. Avec leurs bonnes propriétés physico-chimiques et mécaniques et un relatif faible coût, les matériaux composites à base de résine époxy sont des matériaux de premier choix pour ce type d’application. Cependant, la réduction de la taille des connexions électriques de cuivre (largeur < 1 µm), implique que l’adhésion cuivre/époxy soit améliorée. Dans la littérature, des études ont montré que le taux de réticulation des résines epoxy est un paramètre clé, contrôlant la résistance chimique de la résine epoxy (vis-à-vis des procédés industriels d’impression de cuivre par voie chimique) et les propriétés d’adhésion du cuivre sur le substrat composite.L’objectif de cette thèse est d’étudier de façon approfondie la cinétique de réticulation d’un composite époxy/silice (ABF) utilisé en production de masse dans l’industrie microélectronique afin de proposer un protocole de fabrication des circuits imprimés en fonction du taux de réticulation.Le comportement rhéologique du matériau composite en fonction du taux de réticulation a été étudié par analyse mécanique dynamique (DMA). L’influence du taux de réticulation sur les processus de gélification et de vitrification est présentée et une analyse du comportement viscoélastique de la résine epoxy près de la transition vitreuse est discutée. Le modèle WLF est utilisé pour décrire la dynamique de réseau du polymère. La cinétique de réticulation du composite a été étudiée in situ en spectroscopie proche-infrarouge (NIR) et en calorimétrie différentielle à balayage (DSC) en modes isotherme et non-isotherme. L’analyse iso-conversionnelle a permis de déterminer l’énergie d’activation de la réaction de réticulation. Cependant, une modélisation plus approfondie de la cinétique de réticulation a été nécessaire en raison d’une contribution de diffusion s’ajoutant à la contribution chimique de la réaction. Cette étude a montré que les cinétiques de réticulation peuvent être décrites par le modèle auto-catalytique d’ordre n combiné aux modèles de Rabinowitch et WLF-modifié, modèles tenant compte de la contribution de diffusion. Ce modèle a permis de prédire le comportement du matériau dans une large gamme temps/température et d’établir le diagramme Température-Temps-Transformation du matériau .Compte tenu de l’importance du taux de réticulation sur les propriétés d’adhésion des connexions électriques de cuivre, une méthode de mesure du taux de réticulation sur des PCB industriels a été développée. La spectroscopie infrarouge en réflexion diffuse (DRIFTS) s’est avérée être une technique d’analyse parfaitement adaptée. L’influence du taux de réticulation sur l’étape de “desmear” du procédé de fabrication a également été étudiée. Cette étape, constituée d’une phase de gonflement de la résine epoxy (swelling) suivie d’une attaque oxydante au permanganate et d’une étape de réduction, est déterminante quant à la rugosité de surface obtenue et donc l’adhésion du cuivre sur le substrat composite. Une méthode originale a été développée pour déterminer le profil de diffusion de l’agent de gonflement (sweller) au sein du matériau, méthode alliant microtomie et analyse chromatographique. L’effet des conditions de “swelling” sur la rugosité finale du matériau a été déterminé par microscopie à force atomique (AFM). Des tests d’adhésion du cuivre ont également été réalisés afin d’étudier l’influence du taux de réticulation de la résine epoxy et de la rugosité de surface du composite sur la force d’adhésion. Finalement, une bonne adhésion du cuivre (environ 4 N/cm) pour des surfaces de faible rugosité (< 10 nm). / Due to the increasing miniaturization in microelectronics the manufacturing of densely interconnected multilayer printed-circuit boards (PCB) is needed. With their well-balanced physico-chemical and mechanical properties and low cost, epoxy-based composites are insulating materials of prime choice. However, to achieve interconnections at a lower scale (copper line width down to ca. 1 µm), the adhesion between the composite substrate and the copper interconnections must be enhanced. Previous studies showed that the degree of curing of the epoxy matrix (i.e. conversion of crosslinking reaction) is one key-parameter, driving the matrix chemical and mechanical resistance (during the PCP manufacturing process) and the composite/copper line adhesion properties.In this work we present and discuss an in-depth study of the curing kinetics of an epoxy/silica composite (ABF) relevant to the microelectronics industry. The final objective is to propose a process protocol of the PCB manufacturing as function of the degree of curing.The rheological behaviour of the composite material is investigated by dynamic mechanical analysis (DMA). The gelation and vitrification mechanisms are presented as a function of the degree of curing. The viscoelastic behavior of the epoxy matrix near the glass-transition is studied and is shown to be well-described by the WLF model.The curing kinetics of the epoxy composite are studied by in situ near-infrared (NIR) spectroscopy and both isothermal and non-isothermal differential scanning calorimetry (DSC). Iso-conversional analyses are performed to determine the apparent activation energy of the curing reaction. Due to a non-negligible contribution of the diffusion part in the curing reaction, further modelling was needed to achieve a complete description of the curing kinetics. This study showed that the curing kinetic is well-described by the nth-order autocatalytic fitting model in combination with the Rabinowitch/modified-WLF models, taking into account the diffusion contribution. This model is used to predict the material behaviour in a wide time/temperature range and to propose a Temperature-Time-Transformation diagram of the material.Due to the influence of the degree of curing on the adhesion of copper electrical lines, an experimental method for the measurement of the degree of curing of industrial PCB was developed. Diffuse-reflectance infrared spectroscopy (DRIFTS) is found to be a versatile and accurate technique. The influence of the degree of curing on the “desmear” step of the PCB manufacturing process is studied as well. The “desmear” step proceeds in the swelling of the epoxy matrix and the subsequent permanganate etching and reduction reactions. The “desmear” step is quite important regarding the composite surface roughness and, as a consequence, the adhesion of the copper lines. An original method for the determination of the diffusion profile of the sweller through the depth of the material was developed using microtomy and chromatography. The effect of swelling experimental parameters on the final roughness of the composite is determined by atomic force microscopy (AFM). Adhesion tests of copper lines on the composite substrate are performed to study the influence of the initial degree of curing and the roughness on the peel strength. Good adhesion of copper (about 4 N/cm) is achieved for a low substrate roughness (< 10 nm).
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Prezidentská volba F. D. Roosevelta v USA v roce 1932 a její reflexe v dobovém českém tisku / Czech Printed Press Reflection of the Presidential Election of F. D. Roosevelt in the USA in 1932ČERNÝ, Aleš January 2018 (has links)
The aim of this thesis is to analyse political situation of the USA in the early 30´s of the 20th century, culminating with the election of Franklin Delano Roosevelt as the president of the USA. Afterwards the author is going to evaluate how the czech written press in the independent Czechoslovakian republic has reacted on the mentioned affairs and connections between them, while it was divided in almost every single part of the political spectre.
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Printable and printed perovskites photovoltaic solar cells for autonomous sensors network / Cellules solaires photovoltaïques pérovskites imprimables et imprimées pour réseau de capteurs autonomesGheno, Alexandre 15 December 2017 (has links)
Ce travail de thèse a pour sujet la conception des cellules solaires photovoltaïques à base de pérovskite hybride par le biais de la technologie d’impression jet d’encre. Les deux premiers chapitres font la présentation du contexte de la thèse, à savoir l’alimentation d’un réseau autonome de capteurs, et passent en revue les aspects scientifiques des technologies jet d’encre et photovoltaïque de nouvelle génération. Le troisième chapitre présente la mise au point d’une cellule photovoltaïque à l’état de l’art et son évolution vers une architecture imprimable à basse température de recuit. La problématique de la stabilité des cellules photovoltaïques à pérovskite est aussi abordée. La dernière partie présente les différents aspects et problématiques de l’impression par jet d’encre des trois couches internes d’une cellule solaire pérovskite. Au terme de ce travail la possibilité d’imprimer des cellules solaires pérovskites avec des rendements supérieurs à 10 % a été démontrée, le tout en condition ambiante et à basse température. / This thesis is about the design of photovoltaic solar cells based on hybrid perovskite using inkjet printing technology. The first two chapters present the context of the thesis, namely the powering of an autonomous sensor network, and review the scientific aspects of inkjet and photovoltaic technologies. The third chapter presents the development of a state-of-the-art photovoltaic cell and its evolution towards a printable architecture at low annealing temperatures. The problem of the stability of photovoltaic cells with perovskite is also discussed. The last part presents the different aspects and problems of the inkjet printing of the three inner layers of a perovskite solar cell. At the end of this work the possibility of printing perovskite solar cells with efficiencies higher than 10% has been demonstrated, all in ambient conditions and at low temperature.
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