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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

Printing conductive traces to enable high frequency wearable electronics applications

Lim, Ying Ying January 2015 (has links)
With the emergence of the Internet of Things (IoT), wireless body area networks (WBANs) are becoming increasingly pervasive in everyday life. Most WBANs are currently working at the IEEE 802.15.4 Zigbee standard. However there are growing interests to investigate the performance of BANs operating at higher frequencies (e.g. millimetre-wave band), due to the advantages offered compared to those operating at lower microwave frequencies. This thesis aims to realise printed conductive traces on flexible substrates, targeted for high frequency wearable electronics applications. Specifically, investigations were performed in the areas pertaining to the surface modification of substrates and the electrical performance of printed interconnects. Firstly, a novel methodology was proposed to characterise the dielectric properties of a non-woven fabric (Tyvek) up to 20 GHz. This approach utilised electromagnetic (EM) simulation to improve the analytical equations based on transmission line structures, in order to improve the accuracy of the conductor loss values in the gigahertz range. To reduce the substrate roughness, an UV-curable insulator was used to form a planarisation layer on a non-porous substrate via inkjet printing. The results obtained demonstrated the importance of matching the surface energy of the substrate to the ink to minimise the ink de-wetting phenomenon, which was possible within the parameters of heating the platen. Furthermore, the substrate surface roughness was observed to affect the printed line width significantly, and a surface roughness factor was introduced in the equation of Smith et al. to predict the printed line width on a substrate with non-negligible surface roughness (Ra ≤ 1 μm). Silver ink de-wetting was observed when overprinting silver onto the UV-cured insulator, and studies were performed to investigate the conditions for achieving electrically conductive traces using commercial ink formulations, where the curing equipment may be non-optimal. In particular, different techniques were used to characterise the samples at different stages in order to evaluate the surface properties and printability, and to ascertain if measurable resistances could be predicted. Following the results obtained, it was demonstrated that measurable resistance could be obtained for samples cured under an ambient atmosphere, which was verified on Tyvek samples. Lastly, a methodology was proposed to model for the non-ideal characteristics of printed transmission lines to predict the high frequency electrical performance of those structures. The methodology was validated on transmission line structures of different lengths up to 30 GHz, where a good correlation was obtained between simulation and measurement results. Furthermore, the results obtained demonstrate the significance of the paste levelling effect on the extracted DC conductivity values, and the need for accurate DC conductivity values in the modelling of printed interconnects.
2

Techniques of Music Printing in the United States, 1825-1850

Mayo, Maxey H. (Maxey Huffman) 12 1900 (has links)
Music printing in the United States between 1825 and 1900 was in a constant state of change as older techniques improved and new processes were invented. Beginning with techniques and traditions that had originated in Europe, music printers in America were challenged by the continuous problem of efficiently and economically creating ways of transferring a music image to the printed page. This study examines the music printing techniques, equipment, and presses of the period, as well as the progression from music type to engraved plate and lithograph stone. A study of the techniques of altering music printing plates helps explain the differences occurring in prints from the same edition and will help further our understanding of this important aspect of music historiography.
3

Printable Biosensors based on Organic Electrochemical Transistors with a Platinized Gate Electrode / Tryckbara biosensorer baserade på organiska elektrokemiska transistorer med en platinerad gate-elektrod

Broman, Eva January 2012 (has links)
There is a great demand for low-cost disposable sensors in a variety of markets, such as the food chainand health care. No assay is performed more than that of glucose and approximately 85 % of the entirebiosensor market accounts for glucose biosensors. Each year, 6 billion glucose assays are performed andthe majority of them are based on electrochemical detection. Organic electrochemical transistors(OECTs) have favorable properties in terms of low operating voltages and have previously been used asbase for electrochemical detection of glucose. A low-cost disposable biosensor can be achieved by theuse of high throughput printing techniques. Up until now, no printable biosensors based on organic electrochemicaltransistors have been developed. In this thesis a printable miniaturized prototype for a glucose biosensor based on an OECT with a platinizedgate electrode has been designed, developed and evaluated. The biosensor has been functionalizedwith the enzyme glucose oxidase. Different platinum deposition techniques have been used to depositplatinum onto the printed carbon gate electrode: electrodeposition, platinum nanoparticle solutiondeposited either by inkjet printing or pipetting and thermal evaporation. The gate electrodes were characterized with cyclic voltammetry in hydrogen peroxide, ferricyanide andglucose. The characterizations revealed no significant differences between the different deposition techniques.However, with gate electrodes produced by printed carbon followed by electrodeposition ofplatinum it was possible to sense glucose in a concentration in the range of the values for diabetic persons.Thus, the electrodes are a promising option as gate electrodes in a glucose biosensor based on anOECT. The characteristics of the OECT revealed that the responses resembled a transistor.
4

Avaliação da adaptação marginal de copings cerâmicos obtidos por diferentes métodos de moldagem / Evaluation of the marginal adaptation of ceramic copings obtained by different molding methods

Pinto, Tatiana Saretta Ferreira [UNESP] 13 August 2018 (has links)
Submitted by Tatiana Saretta Ferreira Pinto (tatiorto13@hotmail.com) on 2018-10-11T15:04:44Z No. of bitstreams: 2 tese final para impressão.pdf: 1518062 bytes, checksum: f5bc8c4dd9de4a0b0698c8932e0aef20 (MD5) tese final para impressão.pdf: 1518062 bytes, checksum: f5bc8c4dd9de4a0b0698c8932e0aef20 (MD5) / Approved for entry into archive by Silvana Alvarez null (silvana@ict.unesp.br) on 2018-10-16T21:13:07Z (GMT) No. of bitstreams: 1 pinto_tsf_me_sjc.pdf: 1518062 bytes, checksum: f5bc8c4dd9de4a0b0698c8932e0aef20 (MD5) / Made available in DSpace on 2018-10-16T21:13:07Z (GMT). No. of bitstreams: 1 pinto_tsf_me_sjc.pdf: 1518062 bytes, checksum: f5bc8c4dd9de4a0b0698c8932e0aef20 (MD5) Previous issue date: 2018-08-13 / O objetivo desse estudo foi avaliar a adaptação marginal de copings cerâmicos obtidos pelos métodos de moldagem convencional e escaneamento. Os modelos foram separados em 3 grupos para avaliação e todas as coroas foram confeccionadas sobre um modelo mestre previamente fabricado em CoCr. Grupo 1: Com o auxílio de uma moldeira individual cilíndrica de acrílico foram reproduzidas 10 moldagens com silicona de adição (Panasil) no modelo mestre pela técnica de moldagem dupla e replicados dez modelos físicos em gesso pedra Fuji Rock.Sobre esses modelos foi realizado o enceramento dos copings, confecção dos sprues de cera e sobre eles foi realizada a injeção da cerâmica Grupo 2: foram realizadas 10 moldagens diretas com scanner extraoral (Swing Dental Scanner) no modelo mestre. As imagens foram obtidas através do software Exocad e copings em IPS-Emax CAD foram confeccionados em fresadora (Ceramill Motion 2) para posterior sinterização da cerâmica. Grupo 3: foram realizadas 10 moldagens diretas com scanner intraoral (CEREC Bluecam) no modelo mestre. As imagens foram obtidas através do software Exocad. Copings em IPS-Emax CAD foram confeccionados em fresadora (Ceramill Motion 2) para posterior sinterização da cerâmica. Os copings de cerâmica não foram cimentados no modelo mestre, apenas posicionados e mantidos com pressão constante de 1,4 a 1,5 kg durante a medição, com a ajuda de um delineador adaptado para esse trabalho, onde oito pontos eletivos foram usados como referência para medir a distância vertical entre a linha de término do modelo mestre e a linha de término dos copings. A margem em cada ponto foi medida 3 vezes com estéreomicroscópio Discovery V20 (ZEISS). A média de desadaptação marginal foi calculada e submetida ao teste de variância de um fator ANOVA com nível de significância de 5% e foram obtidos os seguintes resultados: 66,15µm para o grupo 1; 67,48µm para o grupo 2 e 72,91µm para o grupo 3,verificando assim que esses valores não diferem estatisticamente e todos estão dentro do limite de aceitabilidade clínica / The objective of the study was to evaluate the marginal adaptation of ceramic crowns obtained by conventional molding and scanning methods. The models were separated into 3 groups for evaluation and all the crowns were made on a master model previously manufactured in CoCr. For group 1: With the aid of a single cylindrical acrylic tray the master model was molded 10 times with Panasil in the master model by the technique of double molding and replicated ten physical models in stone gypsum Fuji Rock. On these models was done the waxing of the copings, making the sprues of wax and on them was carried out the injection of the ceramics In group 2, 10 direct impressions were performed with the Swing Dental Scanner (Korea) extra oral scanner in the master model. The images were obtained through the software Exocad (GmbH) and copings in IPS-Emax CAD were made in the Ceramill Motion 2 (Amanngirrbach) mill for subsequent sintering of the ceramics. In group 3, 10 direct impressions were performed with the CEREC Bluecam intraoral scanner (Sirona Dental Systems) in the master model. The images were obtained through the Exocad (GmbH) software. IPS-Emax CAD copings were made in the Ceramill Motion 2 (Amanngirrbach) mill for subsequent sintering of the ceramic. Ceramic copings were not cemented in the master model, only positioned and maintained with a constant pressure of 1.4 to 1.5 kg during the measurement, with the aid of an eyeliner adapted for this work, where eight elective points were used as reference to measure the vertical distance between the end line of the master model and the end line of the copings. The margin at each point was measured 3 times with stereo microscope Discovery V20 (ZEISS). The mean was calculated and submitted to the ANOVA variance test "with a significance level of 5% and the following results were obtained: 66.15μm for group 1; 67.48μm for group 2 and 72.91μm for group 3, thus verifying that these values do not differ statistically and all are within the limit of clinical acceptability.
5

CAMOLUTION : Contemporary surface pattern expressions in textile design.

Porcher, Mathieu January 2017 (has links)
Camolution is a project that explores the camouflage pattern in a textile designcontext. The motive is to reinterpret an obsolete concealment function andinstead, to hide and reveal visual textile aspects within the pattern. Theprimary aim of this work is to develop a contemporary camouflage patterncollection of printed and knitted textiles, and to explore the concealmentfunction through visual deceptions. The patterns were developed witha method that uses a selection of rules in colour contrasts,style influences and textile proprieties to design a series of patternexperiments. The final pattern designs were screen printed, digitalprinted and knitted, and applied as garment prototypes. This part wasdone in collaboration with the fashion brand Björn Borg. The result setsout a collection of textiles and clothes connected by three differentconcepts of misled vision. It was found that the camouflage function in thiswork was an efficient tool to advertise the brand symbols within the textiles.This work proposes an alternative design method of using the camouflageconcept in textile design, contributing with new expressions, techniquesand qualities.
6

Kalibrace citlivosti dozimetru viditelného světla / Sensitivity calibration of visible light dosimeter

Škarvadová, Adéla January 2018 (has links)
The diploma thesis deals with light dosimeters and modern printing and coating techniques for thin-film formation. The subject of experimental study is the optimization of photosensitive compositions for the preparation of disposable, printed and thin-film dosimeters for visible light. Sensitivity, reproducibility and irreversibility of their color change were optimized. Compositions were calibrated for desired light dose. Functional samples for gallery were fabricated and stability of functional samples were tested at high temperatures of storing.
7

Optimalizace organických solárních článků / Optimization of organic solar cells

Kratochvíl, Matouš January 2017 (has links)
This diploma thesis focuses on the preparation of large-scale organic solar cells using techniques compatible with large volume production. The theoretical part consists of research summarizing the basic theoretical background of the function of organic solar cells and the current state of investigation of the shift from laboratory to large-scale production. The experimental part deals with the optimization of methods of preparation of layers of structure of solar cells, which can be converted into industrial scale.
8

Films réinscriptibles sur supports souples / Rewritable films on flexible substrates

Tricot, Fanny 03 February 2016 (has links)
Les travaux précédents du laboratoire Hubert Curien ont permis d’élaborer des films photosensibles Ag : TiO2 sur verre, support de marquage de motifs actualisables ou permanents. Une adaptation de ces travaux aux supports plastiques et papiers est ici proposée afin d’élargir les domaines d’application potentiels au marquage sécurité des produits par exemple. Des techniques d’élaboration de films Ag : TiO2 compatibles avec les substrats considérés ont donc été développées. Deux voies ont été envisagées. La première utilise la chimie du Sol-Gel combinée à la méthode EISA et des procédés de dépôt tel le spin-coating, le jet d’encre ou la flexographie pour former un film mésoporeux de TiO2 sur les supports. Des traitements basés sur une extraction par solvant ou un recuit infrarouge ont été imaginés afin de libérer la porosité du film sans dégradation du support. Pour réaliser les films sur papier, un sel d’argent est ajouté au Sol avant son dépôt. Dans les cas des films élaborés sur plastique, l’argent est incorporé par imprégnation du matériau dans une solution de sel d’argent. La deuxième voie d’élaboration propose de formuler une encre aqueuse jet d’encre de nanoparticules de TiO2 et d’ions argent, en adaptant la composition d’une suspension commerciale de TiO2 aux exigences du jet d’encre. Après dépôt, l’encre est séchée par recuit infrarouge. Le comportement photochromique sous expositions lumineuses UV et visible des différents films permet leur coloration et décoloration de façon réversible. Les films Sol-Gel déposés sur plastique peuvent également être support de photo-inscriptions permanentes générées par irradiation par une lumière visible d’une certaine intensité / Previous research conducted at laboratory Hubert Curien led to the development of photosensitive Ag: TiO2 films on glass as support for updatable or permanent patterns. An adaptation of this work to plastic and paper substrates is proposed here to broaden the possible application areas such as goods secure labeling, for example. Fabrication techniques of Ag: TiO2 films compatible with flexible substrates have been developed, using two different paths. The first uses the combination of Sol-Gel chemistry with the EISA method. Deposition processes such as spin coating, inkjet or flexographic printing are used to form a mesoporous film of TiO2 on substrates. Treatments based on solvent extraction or infrared annealing have been devised to release the porosity of the film without damaging the supports. Silver salt is either introduced into the titania pores by soaking the films into a silver salt solution or added to the sol before its coating. The second developed option proposes formulating an aqueous ink jet ink made of TiO2 nanoparticles and silver ions by adapting the composition of a commercial suspension of TiO2 with the requirements of the ink jet process. After printing, the ink is dried by infrared annealing. The photochromic behavior under UV and visible light exposures of fabricated films allows to get coloring and bleaching reversibly. Sol-Gel films coated on plastic can also be a support for permanent colored patterns realized by irradiation with a visible light of certain intensity

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