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Influência dos compostos na manufatura por impressão 3Dprinter no comportamento mecânico biomodelos /Sales, Nicolas Coelho January 2017 (has links)
Orientador: Ruis Camargo Tokimatsu / Resumo: Na medicina atual, uma técnica destaca-se cada vez mais, a biomodelagem. Esta técnica consiste na construção de um biomodelo físico a partir de imagens bidimensionais (de tomografias, ressonâncias, ultrassom), que são tratadas e através de softwares transformadas em um biomodelo virtual que por fim torna-se um biomodelo físico, impresso por uma impressora tridimensional, possibilitando a equipe médica, a percepção de detalhes dificilmente observados apenas através de imagens bidimensionais. Porém o material importado utilizado na biomodelagem é de custo elevado. Neste trabalho o objetivo foi através de uma formulação tida como ideal, publicada no artigo de (Meira), variar as porcentagens de sua composição, o ligante utilizado, o método de mistura, as granulometrias dos pós e adicionar um novo constituinte (sulfato de magnésio), e assim, adquirir um material mais barato e observar qual a influência da composição e granulometria em propriedades fundamentais para a qualidade de um pó para manufatura aditiva, tais como fluidez para distribuição homogênea, alto empacotamento das partículas para maximizar a densidade das peças, espessura da camada maior que as dimensões dos aglomerados e bom acabamento superficial após a camada ser depositada. Posteriormente, foram produzidos corpos de prova com diferentes composições, granulometrias e submetidos a ensaios de compressão e flexão três pontos. Após estes ensaios, médias e desvios padrões foram calculados para cada composição e granul... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
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Fabrication and research of 3D complex scaffolds for bone tissue engineering based on extrusion-deposition techniqueChen, Zhichao January 2017 (has links)
Fabrication of scaffold is the key for bone tissue engineering, which is commonly regarded as the most potential route for repairing bone defects. Previously, porous ceramic scaffolds were fabricated through a variety of traditional methods, like moulding and casting, but most of them cannot produce customised tissue-engineered scaffolds. Therefore, 3D printing methods are gaining more attention and are currently being explored and developed to make scaffolds with acceptable biocompatibility. With the considerable development of bone tissue engineering, the bioactivity of scaffolds is becoming increasingly demanded, which leads to new methods and techniques to produce highly biomimetic bone scaffolds. In this study, a new fabrication process to optimise the structures of scaffolds was developed, and intensive researches were performed on the porous scaffolds to confirm their advantages in biological performance. Specifically, by combination of motor assisted extrusion deposition and gas-foaming (graphite as the porogen) technique, hierarchically porous scaffolds with improved microstructures, i.e. multi-scaled pores from nanometre to millimetre (nm-μm-mm), was successfully developed. In this thesis, the optimal content of porogen for scaffolds was studied in terms of compressive strength and in-rod porosities. The most concerned physicochemical properties of scaffolds were carefully examined and the results revealed that such scaffolds exhibit excellent physicochemical properties owing to hierarchically porous structures. Due to additional in-rod micropores and increased specific surface area, along with better hydrophilicity, hierarchically porous scaffolds exerted complete superiority in biological activity, including promoting cellular proliferation of osteoblasts, adhesion and spreading status, as well as the ability to induce cellular differentiation.
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WOODEN : in other formsTennberg, Hannes January 2018 (has links)
No description available.
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Design virtual na reconstrução auricular com material autógenoPinheiro, Rogélio Carpes January 2015 (has links)
As cirurgias de reconstrução parcial ou total de orelha são um desafio na medicina, exigindo técnicas complexas e qualificadas, sendo as mais utilizadas àquelas que fazem uso de material autógeno (cartilagem da costela do próprio paciente). Trata-se de um processo artesanal em que o cirurgião deve esculpir manualmente a cartilagem para formar o modelo tridimensional da orelha, denominado framework, dessa forma, o resultado final depende, principalmente, da habilidade do cirurgião plástico. Tendo isso em vista, busca-se, neste trabalho, empregar as tecnologias computacionais utilizadas no Design Virtual para auxiliar o planejamento cirúrgico, utilizando digitalização tridimensional e fabricação digital para aprimorar o resultado da técnica de reconstrução auricular. A metodologia proposta sugere a digitalização tridimensional do paciente e, a partir disso, são projetados templates cirúrgicos para auxiliar a modelagem e o posicionamento do framework. A aplicação cirúrgica valida alguns pontos e possibilita o estudo de melhorias em determinados templates, utilizados então em outras duas reconstruções, obtendo-se resultados positivos. Assim, o uso do Design Virtual mostra-se confiável e útil na cirurgia de reconstrução auricular, levando à melhoria no planejamento e, assim, diminuição do tempo cirúrgico, sem riscos ou complicações ao paciente e com melhores resultados anatômicos. / The partial or total reconstruction of ear is a challenge in plastic surgery, requiring complex and skilled techniques. The most successful reconstructions use autogenous material (cartilage from the patient's own rib). It is a handmade process in which the surgeon must manually sculpt the cartilages to form the three-dimensional model of the ear, usually called as framework. Considering this, the final result depends mainly on the plastic surgeon's skill. In this scenario, the aim of this research is employ computer technologies used in Virtual Design to aid surgical planning, using three-dimensional scanning and digital manufacturing to improve the result of ear reconstruction technique. The proposed methodology suggests surgical templates, based on 3D patient scan, designed to assist the modeling and positioning of the framework. The surgical application validates some points and allows the study of improvements in certain templates, then used in other two surgeries, with positive results. Thus, the use of Virtual Design proves to be reliable and useful in ear reconstruction surgery, leading to improved planning and decreasing surgical time, without any risks or complications for the patient and with better anatomical results.
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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 methodsPinto, Tatiana Saretta Ferreira [UNESP] 13 August 2018 (has links)
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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.
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Laser writable polymers : markability and durability characteristicsMeruva, Satya P. K. January 2008 (has links)
Characters on computer keyboards are typically printed using one of the two different processes, namely tampographic printing and laser marking. Tampographic printing is time consuming (app. 3-5 mins.), requires skilled workers and employs difficult-to-handle chemicals. On the other hand, the laser marking process is rapid «1 min.), relatively cheap, avoids the need for chemicals and can be carried out with fewer, less skilled operatives than required fortampographic printing. Data from a keyboard production company indicated that there has been a sudden decline in the percentage (from 60% in 2001 to less than 10% in 2003) of laser marked keyboard users over recent years due to a lack of initial contrast of white characters on a dark plastic and poor durability. Under usual office conditions, characters that are used more regularly e.g. 'e' or 's', can be erased in less than 3-6 months. Further, generating a durable high contrast laser mark on dark coloured polymers has also long been an issue. The thesis initially reports on an investigation into the reasons for lack of initial contrast and subsequent discolouration of laser marked and tampo printed characters. This is followed by the development of a range of plastics compounds based on ABS and containing a series of different additives. Criteria for selecting additives that would respond appropriately to a laser are also proposed. The compounds were laser marked under a 1064nm Nd:YAG laser at different power, frequency and speed settings. Plaques of the material were manufactured and laser marked in a grid-like pattern to study both the effect of frequency and speed of marking. The mechanisms associated with the laser-material interaction during the marking process were also investigated using light microscopy and scanning electron microscopy. Microscopy was also employed toobserve the morphology of the marks left by the laser. Finally a unique test regime was designed to characterise the durability of the laser markings under conditions that attempt to simulate those experienced in practice. Results show that aluminium trihydroxide generated superior contrast and exhibited enhanced durability characteristics when compared with nine other micro-additives. Nano-additives, such as nano titanium dioxide portrayed better contrast and durability performance when compared to their micro-size additive equivalents. Analysis of the test plaque results clearly demonstrated that for a specific material compound, it is possible to optimise the laser settings to achieve the best combination of character contrast and durability. Finally, this work is believed to have made a significant contribution to the rather sparse laser markable polymers research field. It will assist in the development of a more fundamental understanding of laser/material interactions and provide a basis for future work in optimising materials formulations for successful laser marking.
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Vers un dispositif de diagnostic point of care intégré : utilisation de la capillarité ainsi que des procédés de thermoformage et de sérigraphie. / Towards an integrated device for point-of-care diagnostics : use of capillarity with thermoforming and screen-printing processes.Gosselin, David 06 October 2017 (has links)
Grâce aux technologies de la microfluidique (i.e. la manipulation d'un fluide dans un système ayant une dimension caractéristique sub-millimétrique), il est possible d'imaginer l'intégration de l'ensemble des fonctions ordinairement réalisées en laboratoire dans un système miniaturisé, réalisant ainsi un laboratoire sur puce. Cela peut ainsi permettre d'allier efficacité et bas-coût requis pour la réalisation de dispositif de diagnositcs médicaux utilisable en dehors d'infrastructure médicalisée, souvent appelés systèmes Point-of-Care. Pour la réalisation d'un tel dispositif, il semble important de concevoir l'intégration des différents composants du système d'une façon cohérente, et en prenant en compte l'ensemble des contraintes imposées par l'application finale ciblée. Le travail effectué au cours de cette thèse a ainsi été réalisé dans l'optique de proposer une réponse à cette problématique d'intégration dans le cadre du développement d'un système microfluidique de diagnostic Point-of-Care basé sur une réaction d'amplification d'ADN isotherme LAMP. Afin de pouvoir proposer un système bon marché et dont l'industrialisation est aisée, nous avons fait appel à l'utilisation du papier comme support et au thermoformage comme moyen de production. En effet à la fois l'industrie papetière et le procédé de thermoformage sont d'ores et déjà existant et proposent des fabrications en série. De plus, le faible coût du matériau et du procédé en question permettent d'envisager un dispositif final à bas-coût. Afin de pouvoir effectuer et détecter la réaction de LAMP la présence de fonctions actives telles qu'un chauffage et un outil de détection est nécessaire. Pour ces dernières, l'intégration a été réalisée par procédé sérigraphique. Le chauffage est effectué par effet Joule grâce au dépôt d'une couche d'encre conductrice à base de carbone. La détection est quant à elle faite par méthode potentiométrique, à l'aide d'électrode couverte de polyaniline. Il sera également montré que l'utilisation de ces méthodes de fabrication est pertinente en termes d'intégration car elles permettent une superposition des différentes fonctions actives, mais également leur intégration directement dans le système microfluidique. / Developments of microfluidics - the study of flows at the sub-millimetric dimensions - have made possible the integration of most of the macroscopic functions of laboratory fluidic systems in a miniaturized system, thus realizing a lab on a chip. This allows the conception of low cost, sensitive and efficient medical diagnostic device usable outside of a medical infrastructure. Such devices are called Point-of-Care (PoC) systems. The design and fabrication of such devices requires an elaborated and coherent integration that takes into account all the constraints imposed by the targeted final application.The work reported here, and performed during the PhD internship, is focused on the study of the concept and development of the integration of a PoC device based on the isothermal LAMP (Loop mediated AMPlification) reaction for the molecular analysis of DNA. In order to offer a cheap and easily industrialized system, we investigate the use of paper as the chip material and thermoforming as the mean to build the channels. These two techniques are currently used in the industry and their adaptation to the fabrication of such devices is easy and low-cost. In order to perform a LAMP reaction, specific functions such as a heating and a detection system are required. The integration of these functions was carried out using screen printing technology. Heating is done by Joule effect using a layer of carbon-based conductive ink. Detection is performed by a potentiometric method, using polyaniline-covered electrodes. It is shown that this approach is compatible with integration when the screen-printing layers are superposed. Besides they can be printed before thermoforming, resulting in a highly integrated system.
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[en] EXPERIMENTAL STUDY OF LIQUID TRANSFER FROM A PLATE AND A ROTATING ROLL / [pt] ESTUDO EXPERIMENTAL DA TRANSFERÊNCIA DE UMA GOTA DE LÍQUIDO ENTRE UMA SUPERFÍCIE PLANA E UM CILINDRO EM ROTAÇÃOBRUNO PEREIRA DE MACEDO 24 January 2018 (has links)
[pt] O processo de impressão por rotogravura é largamente usado na manufatura de revistas pela sua alta velocidade de aplicação. As aplicações deste processo vêm sendo ampliadas para o processo de impressão de circuitos eletrônicos em substratos flexíveis, onde o grau de precisão e controle são bem maiores, já que falhas na impressão levam ao mal funcionamento dos dispositivos fabricados. O processo consiste na transferência de fluido de uma superfície a outra formando uma ponte de fluido. No entanto, essa operação aparentemente simples apresenta mecanismos ainda não bem compreendidos que têm efeito direto na precisão do padrão impresso. O entendimento dos mecanismos de transferência de fluidos entre duas superfícies formando pontes de fluido vai além dos processos de impressão, como tribologia, biologia, recuperação de óleo e microfluídica. Muitos estudos têm sido direcionados para o entendimento da transferência de fluidos entre superfícies e cavidades através do uso de simulação computacional; entretanto os ensaios experimentais são escassos dada a complexidade na execução dos mesmos, principalmente pela pequena dimensão e alta velocidade do escoamento. O objetivo principal
deste trabalho é analisar experimentalmente a dinâmica da transferência de uma gota para um cilindro de borracha em movimento rotacional. O ensaio experimental foi realizado utilizando uma mesa de cobrimento com cilindro motorizado e uma câmera de alta velocidade para visualizar o processo. Os resultados mostram como as propriedades dos fluidos, o número de capilaridade, a posição relativa do cilindro
com relação à superfície da gota e a interação fluido-estrutura (molhabilidade) influenciam
o processo de formação da ponte de fluido, o volume de fluido transferido entre as superfícies e o padrão impresso. / [en] Gravure printing process is widely used for the production of magazines
because of its high speed. Gravure printing application is being expanded to flexible
electronic circuits, at which the degree of precision is much higher, since small
printing defects can lead to circuit malfunctioning. Gravure printing process consists
in liquid transfer from one surface to another, forming a liquid bridge. However,
this seemingly simple operation has flow phenomena not well understood that
have a direct impact on the printing pattern. Liquid transfer forming liquid bridges
goes beyond printing processes and includes applications such as tribology, biology,
oil recovery and microfluidics. There are many studies driven towards the fundamental
understanding of liquid transfer between surfaces and cavities by computational
simulation. However, experimental analyses are rare because of the complexity
of the problem, mainly associated with the small scale and high speed of the
flow. The goal of this research is to analyze experimentally the liquid transfer dynamics
of a liquid drop to a rotating cylinder. The experiments were done using a
draw-down coating apparatus with a rotating roll and a high-speed camera for flow
visualization. The results show how different liquid properties, surface wettability
and operating conditions affect the formation of the liquid bridge, the volume of
liquid transfer and the printing pattern.
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Etude et optimisation de nouveaux types de capteurs pour la détection de polluants en milieu aquatique / Study and optimization of new types of sensors for the detection of pollutants in the aquatic environmentLapeine, David 13 December 2016 (has links)
Dans cette thèse, nous présentons l’étude et la réalisation de micro-capteurs pour les systèmes de gestion des risques naturels. Le cahier des charges était centré sur les possibilités de concevoir des capteurs de polluants pour la surveillance des zones lagunaires dans le sud montpelliérain. Ces capteurs devaient être conçus dans une démarche « faible coût », résistant aux contraintes du milieu et pouvant communiquer et temps réel. Le premier chapitre s’appuie sur une étude bibliographique des différentes méthodes de mesures qui peuvent être utilisées pour faire de la détection de polluants et des matériaux potentiels pour réaliser le capteur. La technique de mesure la plus appropriée pour répondre aux deux premiers points du cahier des charges s’appuie sur la réalisation de transducteurs acoustiques à base de PZT en envisageant un processus technologique basé sur la technique de sérigraphie. Après avoir justifié notre choix de la technique de dépôt par sérigraphie, nous avons détaillé dans le second chapitre le processus technologique, en commençant par la réalisation de l’encre PZT, puis par le dessin des masques et pour finir nous avons détaillé les étapes de dépôt et de fonctionnalisation des transducteurs sur substrat d’alumine et sans substrat. A partir de ces premières réalisations, nous avons présenté les moyens et outils de caractérisation nécessaires pour pouvoir évaluer les différentes étapes du processus technologique mis en place, avec une attention particulière portée sur la qualité du matériau PZT et sur ses propriétés piézoélectriques. Il s’agit d’une part d’études morphologiques (images MEB, profilomètre) et structurelles (diffraction X, EDX) et d’autre part de la mesure des grandeurs piézoélectriques et diélectriques (piézomètre, analyses spectrales et d’impédances). Dans le troisième chapitre nous avons abordé le volet système de cette étude, avec la réalisation de prototypes basés sur les transducteurs sérigraphiés développés au chapitre 2. Les capteurs réalisés ont été testés et étalonnés avec des solutions d’éthanol et de toluène. Pour cela les capteurs sérigraphiés ont été testés sur des bancs expérimentaux afin de valider la technique de la mesure du temps de vol des ondes acoustiques. Dans l’optique de la miniaturisation et de l’intégration du système nous avons mis en place une électronique de commande embarquée à l’aide d’un module dédié. Enfin, pour pouvoir affiner les mesures, nous avons vu que nous pouvions envisager de croiser/corréler plusieurs paramètres. C’est ainsi que nous avons développé un capteur sérigraphié pour la mesure de la conductivité électrique en milieu aquatique. A partir des premiers résultats expérimentaux obtenus nous avons pu valider le principe de la méthode. Dans le quatrième et dernier chapitre de ce manuscrit, nous avons présenté les toutes premières études et réalisations sur la technologie LTCC. En reprenant les paramètres du processus utilisés lors des dépôts sur substrat d’alumine, nous avons réalisé et caractérisé des transducteurs déposés sur une feuille de céramique LTCC. Les premières caractérisations morphologiques et piézoélectriques sont encourageantes et les premiers tests acoustiques ont montré que la génération d’ondes acoustiques était tout à fait possible et qu’une utilisation en vue de la réalisation de capteurs de polluants était envisageable avec cette technologie. Enfin, nous avons pu réaliser une première structure 3D intégrant une cavité d’analyse. Là encore les débuts sont très prometteurs même s’il reste encore beaucoup de travail de « réglage » pour améliorer cette technologie. De plus, cette première réalisation 3D, ouvre de nombreuses perspectives au niveau de l’équipe en vue du développement de nouveaux capteurs. / In this thesis, we introduce the study and implementation of micro-sensors for natural risk management systems. The specification focused on the possibilities to develop a pollutant sensor capable of detecting the presence of hydrocarbons in the lagoon environments of southern Montpellier.These sensors should be designed in a "low cost" gait, resistant to environmental constraints and able to communicate in real time. The first chapter is based on a bibliographical study of the different methods of measurement that can be used for the detection of pollutants and potential materials for making the sensor. The most suitable measurement technology to answer the first two points of the specification is based on the implementation of acoustic transducers made from PZT with a technological process using the screen-printing technique. After justifying our choice of screen-printing deposition technique, we have detailed in the second chapter the technological process: first with the achievement of PZT ink, then with the masks design, and finally with the steps deposition and functionalization of transducers on alumina substrate and without substrate. From these first achievements, we have submitted the means and characterization tools needed to evaluate the different steps of the technological process set up with a focus on the quality of the PZT material and its piezoelectric properties. It is first about morphological (SEM images, profilometer) and structural (XRD, EDX) studies, and then about the measurement of piezoelectric and dielectric values (piezometer, spectral and impedance analyses). In the third chapter we discussed the sensor, with the production of prototypes based on screen-printed transducers developed in Chapter 2. The sensors were tested and calibrated with solutions of ethanol and toluene. For this, the screen-printed sensors were tested in experimental benches to validate the measurement technique of the acoustic waves time of flight. In view of the miniaturization and the integration of the system, we have set an electronic control board with a dedicated module. Finally in order to improve the measurements, we have shown that we could consider crossing/correlating several parameters. Thus, we have developed a screen-printed sensor for the measurement of the electrical conductivity in aquatic environment. From the first experimental results we validated the principle of the method. In the fourth and final chapter of this manuscript, we presented the first studies and achievements on the LTCC technology. By repeating the process parameters used during deposition on alumina substrate, we realized and characterized transducers placed on on a LTCC ceramic sheet. The first morphological and piezoelectric characterizations are encouraging, and the first acoustic tests have shown that the generations of acoustic waves, and a use for the production of sensors of pollutants were possible with this technology. Finally we have been able to achieve a first 3D structure incorporating an analysis cavity. Here again, results are very encouraging, although "adjustments" are needed to improve the technology. Also this 3D realization opens up many opportunities for the team to develop new sensors.
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3D printing in the commons : knowledge and the nature of digital and physical resourcesGarmulewicz, Alysia January 2015 (has links)
3D printers are a type of digital fabrication tool being used by communities committed to shared software, hardware, and digital designs. This shared digital knowledge can be understood as an emerging common resource for the fabrication of physical goods and services. Yet the knowledge associated with physical resources used in 3D printing is less understood. This thesis explores what factors enable or prevent knowledge about physical materials entering the commons. 3D printing, with its particular configuration of digital and physical goods, offers a unique angle to advance the field of commons scholarship. This thesis elaborates the use of commons theory for traversing the boundary between knowledge associated with physical materials and digital content from the perspective of 3D printer users. Particular contributions are made to the branch of knowledge commons theory: notably, how design rules in technological systems can be used to theorise boundaries; how differentiating between the nature of underlying resources can help explain the inclusion of knowledge in the commons; and, how patterns of user engagement with types of knowledge in the commons can be studied over time. To develop these contributions I employ theory on the design rules of technological architecture, and use insights from the study of peer production in online communities. Empirical data comes from a qualitative study of users of Fab Labs, community workshops for digital fabrication, as well as from a quantitative study of the online user forum for the Ultimaker 3D printer.
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