This thesis investigates inkjet printing of fully-integrated modules fabricated on organic substrates as a system-level solution for ultra-low-cost and eco-friendly mass production of wireless sensor modules. Prototypes are designed and implemented in both traditional FR-4 substrate and organic substrate. The prototype on organic substrate is referred to as a Smart Wireless Integrated Module (SWIM). Parallels are drawn between FR-4 manufacturing and inkjet printing technology, and recommendations are discussed to enable the potential of inkjet printing technology. Finally, this thesis presents novel applications of SWIM technology in the area of wearable and implantable electronics. Chapter 1 serves as an introduction to inkjet printing technology on organic substrates, wireless sensor networks (WSNs), and the requirements for low-power consumption, low-cost, and eco-friendly technology. Chapter 2 discusses the design of SWIM and its implementation using traditional manufacturing techniques on FR-4 substrate. Chapter 3 presents a benchmark prototype of SWIM on paper substrate. Challenges in the manufacturing process are addressed, and solutions are proposed which suggest future areas of research in inkjet printing technology. Chapter 4 presents novel applications of SWIM technology in the areas of implantable and wearable electronics. Chapter 5 concludes the thesis by discussing the importance of this work in creating a bridge between current inkjet printing technology and its future.

Three dimensional printing (3DP) is one of the most important solid freeform fabrication (SFF) methods that can produce any material with desired 3D shape by using suitable powder-binder formulations. It differs from the standard molding operations in that it can produce a complicated shapes by a software driven instrument in a laminated fashion and the cost is lower. This method can be applied in a very wide area including drug release operations, biomaterial production especially for bone fixation, prototype production for all purposes, wound dressing etc. It can also be used in obtaining edible objects by using natural polysaccharides with water based binders. In this study, it is aimed to understand the gelling behaviour of some of the gelling materials, which are alginates, pectins and carageenans, and effect of various factors on the production of confectionary objects by means of 3DP process. Effect of multivalent cations, especially Ca2+ ion, on the gelling behaviour of these materials are investigated. The egg-box structure obtained between the polymer segments increases the water holding capacity of the materials and much more chewy structures can be obtained. The molecular changes are followed by Fourier Transform infrared spectroscopy (FTIR). In 3DP applications, the composition of powder and binder, pH, temperature, relative humidity (RH) and machine parameters are important factors affecting the texture of the final object. The texture of the produced specimens is examined by using a texture analyzer and maximum force values are given as g/cm at failure. Alginate and carrageenans are found to be more effective in obtaining chewy textures with Ca2+ ion content in sugar based matrices and optimization of machine parameters are performed to obtain a higher resolution on the specimens.

A subluxação do ombro é a complicação musculoesquelética mais comum das afecções do Sistema Nervoso Central e Periférico, que leva a diminuição do movimento, da função e aumento de dor. Um dos recursos auxiliares utilizados é a órtese que visa corrigir a deformidade, diminuir a dor e proporcionar a função. Este trabalho objetiva projetar e desenvolver o conceito de uma órtese personalizada estabilizadora de ombro. A metodologia de desenvolvimento de projeto de produto esta dividida em três fases: informacional, conceitual e projeto preliminar. Na fase informacional foi realizada pesquisa bibliográfica, de patentes e de mercado e foram entrevistados 30 prováveis usuários; coletados os dados antropométricos, força muscular manual e goniometria. Na fase conceitual, baseado na fase informacional e a partir da Metodologia TRIZ (Teoria da Resolução de Problemas Inventivos) foi proposto um desenho original de órtese híbrida, personalizada e manufaturada em tridimensional, usando estruturas rígidas e faixas de tração, que estabilizem o ombro, diminua a dor e permita a função. A fase do projeto preliminar foi composta por escaneamento tridimensional e uso de softwares que transformam uma imagem digitalizada em formato STL®. Foram realizadas sucessivas evoluções do projeto com geração de desenhos e peças prototipadas que foi avaliada por um usuário. Na fase informacional, a pesquisa de patentes e de mercado mostrou que há uma predominância dos modelos de órtese estabilizadora de ombro com material flexível onde o principal meio de tração é dado por faixas na diagonal e transversal ao tronco, tendendo a posicionar o ombro em rotação interna. Enquanto os usuários relataram expectativa de uma órtese que corrija o posicionamento, tenha melhor conforto térmico e tátil, menos cheiro e de fácil limpeza. O conceito desenvolvido foi: órtese personalizada, fácil de higienizar e de por/tirar, resistente, articulada, leve, em plástico ABS (acrilonitrila, butadieno e estireno) impressão tridimensional, com veste nos dois braços, com faixas de tração rígidas fixadas à cintura, visando à correção da subluxação do ombro com conforto, menor dor além de permitir função. O teste com usuário corroborou com o conceito, pois o protótipo preliminar apresentou bom acoplamento ao tronco, tração satisfatória e possibilidade de realizar um maior número de atividades diárias com menos dor e sensação de cansaço. / The shoulder subluxation is the most common musculoskeletal complication of Central and Peripheral Nervous System disorders, which leads to a decrease in movement, function and increase in pain. One of the resources used to help with this issue is the orthosis that aims to correct the deformity, decrease the pain and provide function. This work aims to design and develop the concept of a personalized shoulder stabilizing orthosis. The methodology used on the product design is divided into three phases: informational, conceptual and preliminary design. In the informational phase, bibliographic, patent and market research were carried out and 30 potential users were interviewed; anthropometric data, manual muscle strength and goniometry were collected. In the conceptual phase, based on the informational data and using TRIZ Methodology (Theory of Inventive Problem Solving), an original concept design of a hybrid orthosis, personalized and manufactured three-dimensional, using rigid structures and traction bands, was proposed to stabilize the shoulder, reduce pain and allow function. The preliminary design phase consisted of tridimensional scanning and the use of software that transformed a scanned image into STL®. Successive evaluations of the project were carried out with generation of designs and prototyped parts - which the user has evaluated. During the informational phase, the patent and market research demonstrated a predominance of the stabilizing orthosis models using flexible material where the main form of traction was given by diagonal and transverse bands to the trunk, tending to position the shoulder in internal rotation. Users have reported the expectation that this orthosis could correct the shoulder positioning and that it has a better thermal and tactile comfort, less smell and easier to clean. The concept developed was: a personalized orthosis, easy to sanitize and to put on/take off, resistant, articulated, lightweight, in ABS (Acrylonitrile butadiene styrene), three-dimensional printing, with a vest in both arms, rigid traction bands fixed to the waist, aiming to correct the shoulder subluxation with comfort, less pain while allowing function. The user test corroborated with the concept, as the preliminary prototype presented good trunk coupling, satisfactory traction and the possibility to perform a greater number of daily activities with less pain and less fatigue caused by limb weight.

L'objectif de cette thèse est d'étudier et d'optimiser le processus de fabrication des mousses métalliques et le comportement thermique du matériau de la mousse d'aluminium/matériau de changement de phase (MCP) par des méthodes expérimentales et numériques. Le processus d’élaboration de la mousse d’aluminium à pore ouvert est développé et optimisé pour contrôler précisément les paramètres de fabrication. Deux modèles de mousse d'aluminium à haute porosité (MAHP)/MCP composite et à faible porosité (MALP)/MCP composite sont établis pour la simulation numérique. En simulant le processus de fusion d'un système de stockage d'énergie, les composites MAHP/MCP et MALP/MCP sont comparés numériquement afin d'évaluer la performance de stockage d'énergie thermique. Les résultats montrent que la mousse d'aluminium améliore nettement le processus de transfert de chaleur dans MCP en raison de sa haute conductivité thermique. La porosité des mousses d'aluminium influence non seulement le processus de fusion du composite mais aussi la performance de stockage d'énergie thermique. Grâce à la collaboration avec EPF, une nouvelle méthode d’élaboration des mousses périodiques d'aluminium à pore ouvert est développée dans cette thèse sur la base d’impression 3D. Le comportement thermique des mousses d'aluminium périodiques à pore ouvert/MCP est analysé expérimentalement et numériquement / The objective of this thesis is to study and optimize the manufacturing process of metal foams and the thermal behavior of the aluminum foam/phase change material (PCM) composite by experimental and numerical methods. The manufacturing process of open-cell aluminum foam is developed and optimized to precisely control the parameters of mufacturing. Two pore-scale models of high porosity aluminum foams (HPAF)/PCM composite and low porosity aluminum foams (LPAF)/PCM composite are established for numerical simulation. By simulating the melting process of a layer energy storage system, the HPAF/PCM and LPAFS/PCM composite are compared numerically in order to evaluate the energy storage performance. The results show that aluminum foam improves greatly the heat transfer process in PCM due to its high thermal conductivity. The porosity of aluminum foams could not only influence the melting process of composite but also the energy storage performance. Thanks to the collaboration with EPF, a new manufacturing method of periodic open-cell aluminum foams is developed based on 3D rapid tooling. The thermal behavior of the periodic open-cell aluminum foams/PCM composite is experimentally and numerically analyzed

M.Tech (Department of Electronic Engineering, Faculty of Engineering and Technology), Vaal University of Technology / In the world of research and development, the ability to rapidly manufacture a prototype or part has become a significant part of the manufacturing process. This requirement has given rise to some unique manufacturing technologies. One of these technologies is Additive Manufacturing (AM), or also more commonly known as 3D printing. There are several AM technologies available and can be divided into three major AM categories namely: liquid, powder and solid sheet based. For this research study, the primary focus will be on powder-based technologies. Powder-based technologies make use of materials in powder form and use different fusion techniques to fuse the powder particles together. All the powder bed fusion technologies consist of the same basic components, namely a powder chamber, build chamber, re-coater and a powder fusion system. For each layer of the build, the re-coater applies a new layer of powder from the powder chamber to the build chamber, and then the specific type of powder fusion system will fuse the powder particles together. This process will then be repeated until the entire build has completed. Currently, powder bed fusion AM platforms do not have re-coating quality feedback into the printing system. Thus, when errors or defects occur on the powder bed surface during the re-coating process, they can affect the structural integrity of the parts. Parts must then be reprinted, which becomes costly due to wasted raw materials, electricity and time. Raw material and sundry wastage was some of the key factors that reduces the overall efficiency of the identified AM technology. Due to the increased problem with wasted materials, the need arose to develop a re-coater monitoring system, which could be used to increase the overall efficiency of a powder-based system. For the development of a re-coater monitoring system, a review of three different types of monitoring technologies such as computer vision, laser scanning and a time-offlight camera was conducted. Based upon the relatively low cost, low computer resource requirements and high accuracy, computer vision was considered as the best suited technology for development of the monitoring system. To select the correct camera to capture images of the powder bed, the required specifications for the camera, lens and mounting position were determined mathematically. A software program was then developed to autonomously detect re-coating errors on the captured image after each re-coating cycle using image processing techniques. Each of the captured powder bed images were divided into 16 equal sized quadrants, where each quadrant was processed individually. Each of the quadrants was examined using an edge detection algorithm to detect any changes in contrast that would indicate a defect or re-coating error. The probability of a possible re-coating error or defect was calculated for each quadrant and displayed as a percentage value. The active re-coater monitoring system was also integrated into the Voxeljet VX500 to validate the system’s operation. The system was used to monitor a total of seven build jobs on the Voxeljet VX500. However, the first three build jobs could not be successfully monitored as some parameters of the system had to be re-adjusted to ensure proper operation. The last four build jobs were monitored successfully and recorded results that proved that the active re-coater monitoring system could indeed detect defects and re-coating errors when they occurred.

No description available.

Yes / Three-dimensional printing (3DP) has demonstrated great potential for multi-material fabrication because of its capability for printing bespoke and spatially separated material conformations. Such a concept could revolutionise the pharmaceutical industry, enabling the production of personalised, multi-layered drug products on demand. Here, we developed a novel stereolithographic (SLA) 3D printing method that, for the first time, can be used to fabricate multi-layer constructs (polypills) with variable drug content and/or shape. Using this technique, six drugs, including paracetamol, cffeine, naproxen, chloramphenicol, prednisolone and aspirin, were printed with dfferent geometries and material compositions. Drug distribution was visualised using Raman microscopy, which showed that whilst separate layers were successfully printed, several of the drugs diffused across the layers depending on their amorphous or crystalline phase. The printed constructs demonstrated excellent physical properties and the different material inclusions enabled distinct drug release profiles of the six actives within dissolution tests. For the first time, this paper demonstrates the feasibility of SLA printing as an innovative platform for multi-drug therapy production, facilitating a new era of personalised polypills.

This study focuses on the use of American Invention Kits from the Smithsonian Institute in conjunction with a 3D printer. In conjunction with a large dataset from a study funded by the National Science Foundation (NSF), this innovative research focuses on the effect the digital fabrication curriculum unit has on gifted and talented students' knowledge and affinity toward the fields of science, technology, engineering, and mathematics (STEM). Students from two rural middle schools in north-central Texas (N = 190) took part in this quantitative study; the students were divided among four subgroups: gifted-contrast (n = 12), gifted-treatment (n = 8), nongifted-contrast (n = 76), and nongifted-treatment (n = 94). The surveys utilized include the STEM Semantics Survey, TIMSS-Limited, and a knowledge assessment for the specific curriculum unit focused on the solenoid. The STEM Semantics Survey is divided into five subsets. Thirty-two separate one-way repeated measures ANOVAs were performed across the surveys and subgroups. Statistically significant results were found on four comparisons. This research holds implications in the areas of advocating for gifted education, collecting field data, utilizing large datasets, and understanding rural schools.

The world is becoming a global place in which science, technology, engineering and mathematics hold a key to a successful future. To help secure this future it is important to engage students early with relevant curriculum that sparks interest and success in STEM fields. However, education reform occurs slowly, so this paper looked at a potential paradigm that can help to bring about change in a middle school environment that harnesses the long standing strengths of learning and education with the integration of technology to create changes in the pedagogy of learners and teachers. The study implemented a transmedia STEM book and evaluated the impact it had on student perceptions of STEM, school attitude, academic achievement, and preferred activity types, providing an example vehicle for change that can be adopted over time. The main findings showed that students who used a 3-Dimensional printer had higher math achievement and a more positive perception of math.

Improved surgical procedures and implant developments for ligament or tendon repair require an in-depth understanding of tissue load-deformation and fatigue properties. Cyclic testing will provide crucial information on the behavior of these materials under reoccurring loads and on fatigue strength. Sparse data are available describing soft tissue behavior under cyclic loading. To examine fatigue strength, a new technology was trialed deploying 3D-printing to facilitate and standardize cyclic tests aiming to determine tendon fatigue behavior. Cadaveric flexor digitorum tendons were harvested and mounted for tensile testing with no tapering being made, using 3Dprinted clamps and holder arms, while ensuring a consistent testing length. Loads ranging between 200 to 510 N were applied at a frequency of 4 Hz, and cycles to failure ranged between 8 and >260,000. S–N curves (Woehler curves) were generated based on the peak stresses and cycles to failure. Power regression yielded a combined coefficient of determination of stress and cycles to failure of R 2 = 0.65, while the individual coefficients for tissues of single donors ranged between R 2 = 0.54 and R 2 = 0.88. The here-presented results demonstrate that S–N curves of human tendons can be obtained using a standardized setting deploying 3D-printing technology