Inkjet printing is a versatile manufacturing method with applications beyond its traditional application in graphics and text printing, particularly in structural and functional materials. This thesis aims to enhance the understanding of DOD inkjet printing processes by investigating the behaviour of solvent mixtures and nanoparticle suspensions to identify the key parameters affecting drop ejection, drying and stacking processes. Drop ejection and flight were investigated with two modes of inkjet printheads, using a range of fluids formulated from solvent mixtures and characterised by the dimensionless Z number. The printable range was found to be 1.17 smaller or equal to Z smaller or equal to 36.76 for a 10 pl (21.5 micro metre diameter) shear-mode Dimatix printhead. However, with an 80 micro metre diameter squeeze-mode MicroFab printhead, the range was found to be narrower with 4.02 smaller or equal to Z smaller or equal to 16.2. However, both printheads were found to show a printable range of Weber number with 0.4 <We <20. Weber number is determined by the drop velocity and hence the actuating pulse. When designing inks for future printing work, not only the fluid properties, but also the pulse voltages need to be considered. The drop stacking and solidification processes of drops containing nano ZrO2 particles were investigated to enhance the understanding of drop drying and drop/drop interactions. In-situ synchrotron X-ray radiography provides a promising method to track the time-evolved solid segregation within printed drops during drying. Both the initial contact angle and substrate temperature during printing strongly influence the drying process and the final dried deposit shape. The drops were first pinned and then there was a slight sliding of the three-phase contact line. Drops were deformed by the stacking of overprinted drops when printed on Kapton tapes and silicon wafer surfaces, but not on glass slides due to the small contact angle of water on glass slides. Crack-like defects were found at the edge of the final dried stacking structures. The coffee stain effects within a single inkjet printed droplet and the 3D structures before and after sintering were investigated to find out the influence of ink properties, printing parameters and substrate temperature on inkjet printed structures. It was found coffee staining was more obvious at high substrate temperatures. When adding 25 vol% ethylene glycol (EG) or 5 wt% polyethylene glycol (PEG), the coffee stain effect is reduced or eliminated under room temperature drying. X-ray tomography has been demonstrated as a valuable tool for the characterization of 3D printed objects and defects that form during their manufacture. Defects were characterised as microvoids or large-scale crack-like defects. The majority of the microvoids revealed are associated with mechanisms and processes within a single drop, e.g. segregation during dryings such as the formation of coffee stains or coffee rings. The size or distribution of microvoids can be controlled by changing the ink formulation, with higher PEG content inks showing lower concentrations of microvoids.

Cet écrit traverse l'encre de la peinture par la sienne propre. Elle a ce corps en partage, à la fois fraternel et inconciliable. L'encre de l'écrit a voulu ici se frayer un chemin de liquidité dans la peinture, donnant à son mouvement l'ébranlement de la couleur, qui est un geste de la matière elle-même. Mon geste, lui, bu par le papier et retiré dans des plis de vagues, opère un glissement jusqu'au blanc d'une page sur la table qui se déploie jusqu'à cet objet singulier qu'est la thèse en arts. De fait, comme la peinture accompagne dans son sillage d'ombres le questionnement d'un regard, son itinéraire sans tracé, l'écrit depuis la peinture, se retourne sur son propre objet — d'une encre à l'autre. La construction d'une parole en prise avec une errance d'atelier est délicate. Elle mêle son corps résonant d'images à celui des mots des poètes, travaillant un langage inconnu au creux de l'impasse même que constituent les mots, la prise de parole. La voix du peintre est la seule que je connaisse. Elle est issue de l'abandon et du dessaisissement à l’œuvre. Elle engage la pensée dans le faire, au milieu d'une déposition qui est celle, multiple, d'un corps d'encre, d'une peinture en éclat, d'un geste et sa dépose, d'une voix et de ses fragments. La déposition appelle le sol. C'est bien de ce sol dont il est question tout au long de cet écrit. Un fondement, comme fondation mais aussi comme ce qui fond sous les pas. Liquide, fluide, mouvante. Une déprise qui est aussi un ancrage, une attache qui est aussi un débord. / This writing goes through the ink of painting through its own. It has this body to share, both fraternal and irreconcilable. Here the ink of writing sought to pave a liquid way in painting, giving to its movement the trembling of color, which is a gesture of matter itself. As for my gesture, drunk by the paper and withdrawn in folds of waves, operates a drift to the white of a page on the table, that unfolds to this singular object that is the thesis in fine arts. In fact, as painting accompanies in its shadowy wake the questioning of a gaze, its course without outline, writing from painting, turns on its own object - from one ink to another. The construction of a discourse in touch with the wandering of the studio is delicate. It merges its body resonant with images with that of words from poets, working an unknown language in the very core of the impasse that constitutes words, access to speech. The painter's voice is the only one I know. It is the result of the abandonment and divestment at work. It engages thought in making, in the midst of a deposition which is, multiple, that of a body of ink, of a radiant painting, of a gesture and its removal, of a voice and its fragments. Deposition calls for the ground. It is that very ground that is being discussed throughout this writing. A grounding, as foundation but also as what melts under the steps. Liquid, fluid, moving. A release that is also an anchor, a tie that is also an overflow.

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-03-03T19:14:52Z No. of bitstreams: 2 Dissertação - Cleon Xavier Pereira Júnior - 2015.pdf: 1262859 bytes, checksum: 35b1053bbf6dfda4e73013526fab8f6b (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-03-04T11:15:57Z (GMT) No. of bitstreams: 2 Dissertação - Cleon Xavier Pereira Júnior - 2015.pdf: 1262859 bytes, checksum: 35b1053bbf6dfda4e73013526fab8f6b (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-03-04T11:15:57Z (GMT). No. of bitstreams: 2 Dissertação - Cleon Xavier Pereira Júnior - 2015.pdf: 1262859 bytes, checksum: 35b1053bbf6dfda4e73013526fab8f6b (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-10-13 / Digital ink technology is available in several electronic devices and can bring contributions to the evaluation process as it allows access to information that was not available in assessments carried out using traditional methods. It is particularly interesting in evaluations involving drawings, since it offers an environment quite similar to pencil and paper, with the advantage of allowing process automation. Thus, the first step is to provide resources to capture, store and reproduce the design done. Then, it is necessary to analyze the collected data. However, analysis of drawings is a complex task and focus of several research projects. Thus, as an initial contribution, this work focuses on the analysis of simple traces. In order to explore digital ink as a means of evaluation, a tool was developed to automate the capture, storage and reproduction of drawings, and test the features and limitations of the analysis of digital ink in order to extract relevant knowledge for the evaluator to make decisions. To test the tool, psychological tests were selected, since in this knowledge domain the use of drawings for assessment is widespread. The tool was developed in two stages. The first, more general, offers resources for test application, storage and later playback for an analysis by the evaluator, not providing resources for automatic analysis of results. Though simple, these resources offer a great contribution, because in addition to storing the final result, which can be visualized as an image, it also stores the design process (allowing the evaluator to follow step by step how the test was performed) in addition to storing other information such as time spent to perform certain steps, the use of rubber etc. The second stage of the tool is the analysis of the stored data. This analysis is test dependent, and should be implemented according to it’s evaluation requirements. As a case study, a test, that uses simple traces, was implemented. The result showed that the digital ink has advantages for carrying out evaluations using drawings as a medium, and should be subject to further research aimed at automating tests with more complex drawings. / A tinta digital está presente em vários dispositivos eletrônicos e pode trazer contribuições para o processo de avaliação por permitir acesso a informações que não estavam disponíveis quando realizadas usando métodos tradicionais. Ela é particularmente interessante em avaliações que envolvem desenhos, já que oferece um meio bastante similar ao lápis e papel com a vantagem de permitir a automatização do processo. Sendo assim, o primeiro passo é oferecer recursos para capturar, armazenar e reproduzir o desenho realizado. Em seguida, é necessário analisar os dados coletados. No entanto, a análise de desenhos é uma tarefa complexa e alvo de diversas pesquisas. Assim, como uma contribuição inicial, este trabalho foca a análise de traços simples (retas). Com o objetivo de explorar a tinta digital como meio de avaliação foi desenvolvida uma ferramenta para automatizar a captura, armazenamento e reprodução de desenhos, e testar as funcionalidades e limitações da análise da tinta digital visando extrair conhecimento relevante para o avaliador poder tomar decisões. Para testar a ferramenta foram selecionados testes psicológicos, já que neste domínio de conhecimento o uso do desenho é bastante difundido. A ferramenta foi desenvolvida em duas etapas. A primeira, mais geral, oferece recursos para a aplicação do teste, seu armazenamento e posterior reprodução para uma análise feita pelo avaliador, não oferecendo recursos para a análise automática dos resultados. Apesar de simples, estes recursos já oferecem uma grande contribuição, pois além de armazenar como imagem o resultado final, armazena também o processo do desenho (permitindo que o avaliador acompanhe passo a passo como o teste foi realizado) e informações adicionais como tempo gasto para atividades, uso da borracha, etc. A segunda etapa da ferramenta é a análise dos dados armazenados. Esta análise é dependente do teste, e deve ser implementada de acordo com os requisitos da avaliação. Como estudo de caso foi implementado um teste que usa traços simples. O resultado mostrou que a tinta digital apresenta vantagens para a realização de avaliações que usam desenhos como meio, e deve ser alvo de futuras pesquisas visando a automatização de testes com desenhos mais complexos.

Identificação de Dispositivos por Radiofrequência, do inglês, Radio Frequency Identification Device (RFID), é uma tecnologia para identificação, rastreamento e gerenciamento de produtos, animais e até mesmo pessoas sem a necessidade de um campo visual. Com o objetivo de alcançar custos menores e a utilização de processos de fabricação menos agressivo ao meio ambiente, tornou-se importante o desenvolvimento de novos tipos de etiquetas (tags). Em vista disso, a fabricação de antenas impressas compactas usando tinta condutiva, representa uma boa opção. O objetivo dessa pesquisa é o projeto e fabricação de antenas impressas sobre substratos flexíveis utilizando tinta condutiva composta de nanopartículas de prata. O desenvolvimento deste tipo de etiquetas é justificado principalmente pelos seguintes motivos. Primeiro, o processo reduz o uso de agentes químicos comumente empregados na fabricação convencional, levando a uma significativa redução no impacto ambiental. Segundo, a fabricação utilizando substratos como, por exemplo, papel ou polímero, reduz substancialmente o custo final da etiqueta. Estudos teóricos e práticos, juntamente com simulações eletromagnéticas foram realizados. Dois processos de prototipagem da etiqueta foram executados: um utilizando uma impressora jato de tinta que funciona propelindo gotas de tinta sobre o substrato e o outro utilizando serigrafia ou silkscreen printing que é muito prático para imprimir formas geométricas através de uma tela de fios trançados. Esses métodos de impressão permitiram a produção rápida da antena sem a necessidade de máscaras de fotolitografia, como é amplamente utilizado na indústria eletrônica. Quatro protótipos foram produzidos e medidas foram realizadas para verificar a viabilidade da utilização dessas etiquetas impressas em relação à sua operação, a confiabilidade das informações armazenadas e a troca de dados com o leitor RFID via interface aérea. Os resultados práticos foram comparados com os obtidos de etiquetas comerciais, onde foi possível verificar que a antena fabricada com tinta condutiva é capaz de capturar e radiar ondas eletromagnéticas de forma eficiente, resultando em uma troca de dados confiáveis através da interface aérea. / Radio Frequency Identification Device (RFID), it is a technology using electromagnetic waves for identifying, tracking and management of products, animals and even people without requiring a visual field. Aiming at achieving low costs and using less aggressive manufacturing processes to the environment, it has become important to develop new types of RFID tags. In view of that, manufacturing compact printed antennas using conductive ink represents a good option. The goal of this research is the design of printed antennas on flexible substrates using silver nanoparticles ink. The developing of this type of tags is justified mainly by the following reasons. First, the process reduces the use of chemical agents commonly employed in conventional manufacturing leading to a significant reduction of the environmental impact. Second, the fabrication using substrates such as paper and polymer foils, substantially reduces the final cost of the tags. Theoretical and practical studies along with electromagnetic simulations were conducted. Two process of RFID prototyping were performed: one using an inkjet printer that operates by propelling particles of conductive ink onto the substrate and another using silkscreen printing that is a very practical method to print geometric forms through a twisted wires screen. These technologies allowed fast production of the antenna without requiring photolithographic masks, as it is widely used in the electronics industry. Four prototypes were produced and measurements were taken to verify the feasibility of using RFID tags printed with conductive ink regarding to its operation, reliability of the stored information and the exchange of data with the RFID reader via air interface. Practical results were compared with those obtained of the commercial tags. It was possible to verify that the antenna manufactured with conductive ink was able to capture and radiate efficiently electromagnetic waves, resulting in reliable exchange of data with the reader through the air interface

Cette recherche tente d’envisager l’art du cinéma comme un art cinégraphique, c’est-à-dire, selon la définition qu’on propose dans ce travail, comme un espace d’images en mouvement se déployant au regard à travers des influx énergétiques qui en animent les composants. Pour en dégager cette substance scripturale et en relever les implications sur le langage du cinéma, cette recherche entreprend un détour par deux pensées de l’image qui ont traditionnellement fait de l’art du tracé un art majeur, manifestant par-là des préoccupations esthétiques et des pensées du langage qui nous semblent en divergence avec celles qui ont conduit l’histoire culturelle occidentale à inventer le cinéma. Que devient alors le cinéma lorsqu’il est investi par ces pensées ? Réciproquement, que peut leur apporter le cinéma en tant que technique, dispositif et matière ? Le premier détour, en posant des questions de mouvement, de geste et de temps, passe par la calligraphie et l’art pictural chinois pour interroger le cinéma en tant que machine à enregistrer, liée à une pensée de la conservation, de la mémoire et de l’événement. Le second détour, en posant des questions de lumière, de regard et d’espace, passe par la calligraphie et l’art pictural musulman pour interroger le cinéma en tant que machine optique, liée à une pensée de la mimésis, de la profondeur et de la monstration. Ces détours servent enfin de base théorique pour penser notre rapport quotidien aux images (numériques principalement), rapport qui se transforme de manière exponentielle et qui reconfigure notre manière de voir, de lire et de toucher les images ; selon un mode précisément cinégraphique. / This research attempts to envisage the art of cinema as a cinegraphic art, that is to say, according to the definition herein, as a space of moving images unfolding themselves to the gaze through energetic impulses that animate its component parts. In order to draw forth this scriptural substance and to ascertain its implications for the language of cinema, this research detours into two realms of thought on the image, which have traditionally elevated the art of drawing into a prominent art form, thus manifesting aesthetic preoccupations and notions of language which we perceive as diverging from those that led Western cultural history to invent cinema. What then becomes of cinema when endowed by these thoughts? Conversely, what can cinema offer them as a technique, a device and a subject? The first detour, by posing questions of movement, gesture and time, journeys through Chinese calligraphy and pictorial art to question cinema as a recording machine, bound to a conception of conservation, memory and of the event. The second detour, by posing questions on light, gaze and space, journeys through Muslim calligraphy and pictorial art to question cinema as an optical machine, bound to a conception of mimesis, depth and of showing. These detours serve as a theoretical grounding for thinking about our everyday relationship to images (mainly digital), a relationship that changes exponentially and reconfigures our way of seeing, reading and touching images; according to a strictly cinegraphic mode.

This is a practice-led research project that seeks to explore the cross-cultural aesthetics and conceptual ideas of an art project. I position myself as an art practitioner who intends to apply the Western modes of technological advancement of digital imaging and ink jet technologies to the substrates used by traditional Chinese artists for ink painting and calligraphy, usually called Xuan Zhi [宣紙]. Through this process, the aesthetics and conceptual ideas of both cultures will be explored, examined, analysed and interrogated for the potential development of a new aesthetics in the context of digital art. There are three major components in this research project; a creative document in the form of a collection of artwork, an exegesis and a collection of documentation. The creative document will be a body of visual image-based artwork that includes a series of collateral works from the ongoing research and practice of the project. It is the negotiated output of a potentially new aesthetics in digital art, specifically in the context of digital still imaging and digital printmaking. The exegesis is an analytical and critical commentary that places the creative document in relevant theoretical, philosophical, cultural and historical contexts. The documentation is a collection of the ongoing empirical practice of ink jet technology on Xuan Zhi. The visual physical form of both the exegesis and the documentation are also included as part of the creative document. These three components together form a unity and are presented as artefacts to represent the main focus of the research - the Poetics of Making.

<p>Flexographic printing is a common printing method in the packaging field. The printing method is characterized primarily by the flexible printing plate and the low viscosity inks which make it suitable for use on almost any substrate. The object of this study was to obtain further knowledge of the some important mechanisms of flexographic printing and how they influence the print quality. The thesis deals with printing primarily on board and liner but also on newsprint with water-borne ink using a full-scale flexographic central impression (CI) printing press. Several printing trials have been performed with a focus on the chemical interaction between the ink and substrate and the physical contact between the ink-covered printing plate and the substrate.</p><p>Multicolour printing exposes the substrate to water from the water-containing ink. The emphasis was to investigate the relation between print quality and water-uptake of the paper surface with heat and water. Printing trials was carried out on substrates possessing a hydrophobic, and also a rather hydrophilic surface using a regular commercial water-borne ink. The favorable effect which water or surfactant solution had on the hydrophobic substrate with regard to print mottle could depend on its surface compressibility in combination with the hydrophobic nature of its surface that could affect the wetting properties.</p><p>Conventional printing involves physical contact between plate and ink and between ink and substrate. A method for measuring the dynamic nip pressure using thin load cells is presented. Print quality was influenced by the plate material. A correction procedure taking into account the size of the sensor was developed in order to estimate the maximum dynamic pressure in the printing nip. An attempt was made to identify essential mechanical and chemical parameters, and also geometrical properties of the plate that affected print quality. Laboratory printing trials were carried out and a multivariate analysis was applied for evaluation of print quality data. The impact of the plate properties on print quality was evident. The essential properties of the plate that influence print quality were the small-scale roughness and long-scale roughness.</p>

The focus of this Ph.D. thesis research is a new piezoelectrically driven micromachined ultrasonic atomizer concept that utilizes fluid cavity resonances in the 15 MHz range along with acoustic wave focusing to generate the pressure gradient required for droplet or jet ejection. This ejection technique exhibits low-power operation while addressing the key challenges associated with other atomization technologies including production of sub-5 um diameter droplets, low-temperature operation, the capacity to scale throughput up or down, and simple, low-cost fabrication. This thesis research includes device development and fabrication as well as experimental characterization and theoretical modeling of the acoustics and fluid mechanics underlying device operation. The main goal is to gain an understanding of the fundamental physics of these processes in order to achieve optimal design and controlled operation of the atomizer. Simulations of the acoustic response of the system for various device geometries and different ejection fluid properties predict the resonant frequencies of the device and confirm that pressure field focusing occurs. High-spatial-resolution stroboscopic visualization of fluid ejection under various operating conditions is used to investigate whether the proposed atomizer is capable of operating in either the discrete-droplet or continuous-jet mode. The results of the visualization experiments combined with a scaling analysis provide a basic understanding of the physics governing the ejection process and allow for the establishment of simple scaling laws that prescribe the mode (e.g., discrete-droplet vs. continuous-jet) of ejection. In parallel, a detailed computational fluid dynamics (CFD) analysis of the fluid interface evolution and droplet formation and transport during the ejection process provides in-depth insight into the physics of the ejection process and determines the limits of validity of the scaling laws. These characterization efforts performed in concert with device development lead to the optimal device design. The unique advantages enabled by the developed micromachined ultrasonic atomizer are illustrated for challenging fluid atomization examples from a variety of applications ranging from fuel processing on small scales to ultra-soft electrospray ionization of biomolecules for bioanalytical mass spectrometry.

This thesis investigates inkjet-printed flexible antennas fabricated on paper substrates as a system-level solution for ultra-low-cost and mass production of RF structures. These modules are designed for the UHF Radio Frequency Identification (RFID) Tags and Wireless Sensor Nodes (WSN); however the approach could be easily extended to other microwave and wireless applications. Chapter 1 serves as an introduction to RFID technology and its capabilities while listing the major challenges that could potentially hinder RFID practical implementation. Chapter 2 discusses the benefits of using paper as a substrate for high-frequency applications, reporting its very good electrical/dielectric performance up to at least 1 GHz. The dielectric properties are studied by using the microstrip ring resonator. Brief discussion on Liquid Crystal Polymer (LCP) is also given in this chapter. Chapter 3 gives details about the inkjet printing technology, including the characterization of the conductive ink, which consists of nano-silver-particles, while highlighting the importance of this technology as a fast and simple fabrication technique especially on flexible organic (e.g.LCP) or paper-based substrates. Chapter 4 focuses on antenna designs. Four examples are given to provide: i) matching techniques to complex IC impedance, ii) proof of concept of inkjet printing on paper substrate through measurement results, iii) demonstration of a fully-integrated wireless sensor modules on paper and show a 2D sensor integration with an RFID tag module on paper. Chapter 5 concludes the thesis by explaining the importance of this work in creating a first step towards an environmentally friendly generation of "green" RF electronics and modules.

Flexographic printing is a common printing method in the packaging field. The printing method is characterized primarily by the flexible printing plate and the low viscosity inks which make it suitable for use on almost any substrate. The object of this study was to obtain further knowledge of the some important mechanisms of flexographic printing and how they influence the print quality. The thesis deals with printing primarily on board and liner but also on newsprint with water-borne ink using a full-scale flexographic central impression (CI) printing press. Several printing trials have been performed with a focus on the chemical interaction between the ink and substrate and the physical contact between the ink-covered printing plate and the substrate. Multicolour printing exposes the substrate to water from the water-containing ink. The emphasis was to investigate the relation between print quality and water-uptake of the paper surface with heat and water. Printing trials was carried out on substrates possessing a hydrophobic, and also a rather hydrophilic surface using a regular commercial water-borne ink. The favorable effect which water or surfactant solution had on the hydrophobic substrate with regard to print mottle could depend on its surface compressibility in combination with the hydrophobic nature of its surface that could affect the wetting properties. Conventional printing involves physical contact between plate and ink and between ink and substrate. A method for measuring the dynamic nip pressure using thin load cells is presented. Print quality was influenced by the plate material. A correction procedure taking into account the size of the sensor was developed in order to estimate the maximum dynamic pressure in the printing nip. An attempt was made to identify essential mechanical and chemical parameters, and also geometrical properties of the plate that affected print quality. Laboratory printing trials were carried out and a multivariate analysis was applied for evaluation of print quality data. The impact of the plate properties on print quality was evident. The essential properties of the plate that influence print quality were the small-scale roughness and long-scale roughness.