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In this work, the use of a lunar regolith simulant as feedstock for the direct ink writing additive manufacturing process is explored, the purpose of which is to enable future lunar in-situ resource utilisation. The feasibility of this approach is demonstrated in a laboratory setting by manufacturing objects with different geometries using methyl cellulose or sodium alginate as binding agents and water as liquid phase together with the lunar regolith simulant EAC-1A to create a viscous, printable ‘ink’ that is used in combination with a custom three-axis gantry system to produce green bodies for subsequent sintering. The sintered objects are characterised using compressive strength measurements and scanning electron microscopy (SEM). It is proposed that the bioorganic compounds used in this work as additives could be produced at the site for a future lunar base through photosynthesis, utilising carbon dioxide exhaled by astronauts together with the available sunlight, meaning that all the components used for the dispersion – additive, water (in the form of ice) and regolith – are available in-situ. The compressive strength for sintered samples produced with this method was measured to be 2.4 MPa with a standard deviation of 0.2 MPa (n = 4). It is believed, based on the high sample porosity observed during SEM analysis, that the comparatively low mechanical strength of the manufactured samples is due to a non-optimal sintering procedure carried out at a too-low temperature, and that the mechanical strength could be increased by optimising the sintering process further.

<p>U mnogim granama tehnike javljaju se problemi<br />merenja protoka fluida. Merne blende, zbog svojih<br />mnogih prednosti predstavljaju najzastupljeniji<br />instrument za merenje protoka fluida kroz cevovode. Sa<br />druge strane njihova upotreba povećava tro&scaron;kove rada<br />industrijskih postrojenja. Jedan od ciljeva ove<br />doktorske disertacije bio je ispitivanje novih oblika<br />mernih blendi u cilju u&scaron;tede energije pri njihovom radu.<br />U ovoj doktorskoj disertaciji predložen je algoritam<br />ispitivanja novih oblika mernih blendi. Takođe je<br />konstruisana i izrađena laboratorijska aparatura za<br />njihovo ispitivanje kao i diferncijalni &quot;U&quot; manometar<br />za merenje malih razlika pritisaka. U okviru ove<br />doktorske disertacije dizajnirana su i ispitana tri nova<br />oblika mernih blendi. U&scaron;teda energije je postignuta<br />dizajnom koji smanjuje otpor merne blende kao<br />elementa cevovoda. Novi oblici mernih blendi, kao i<br />jedna standardnog oblika koja je poslužila kao<br />referentna, ispitani su prema predloženom algoritmu. U<br />prvom koraku merne blende su dizajnirane u<br />programskom paketu Solid Works. Zatim su, prema<br />predloženom algoritmu, ispitane pomoću računarske simulacije u programskom paketu COMSOL Multiphysics. Po dobijanju zadovoljavajućih rezultata računarske simulacije, merne blende su izrađene na 3D &scaron;tampaču, FDM postupkom i ispitane na laboratorijskoj aparaturi. Rezultati laboratorijskih ispitivanja su upoređeni sa rezultatima računarske simulacije. Upoređeni rezultati računarske simulacije i laboratorijskih ispitivanja su pokazali da je računarska simulacija dobro opisivala situaciju. Rezultati laboratorijskog ispitivanja su pokazali znatan efekat u&scaron;tede energije. Takođe je utvrđeno da se pomoću računarske simulacije mogu dobiti podaci na osnovu kojih se može doneti odluka da li novi oblik merne blende treba korigovati ili ima smisla pristupiti laboratorijskom ispitivanju. Algoritam ispitivanja koji je predložen u ovoj doktorskoj disertaciji se pokazao efikasnim.</p><p>&nbsp;</p> / <p>In many domains of technology, there are problems<br />with the measurement of fluid flow. Orifice plates,<br />because of their many advantages, represent the most<br />common instrument for measuring fluid flow through<br />pipelines. On the other hand, their use increases the<br />operating cost of industrial plants. One of the goals of<br />this doctoral dissertation was to test new forms of<br />orifice plates for a reason to save energy during their<br />work. An algorithm for testing new forms of orifice<br />plates is proposed. Also, the laboratory equipment for<br />testing them was designed and made, as well as a<br />differential &quot;U&quot; manometer for measuring small<br />pressure differences. As part of this doctoral<br />dissertation are designed and tested three new forms of<br />orifice plates. Energy-saving was achieved by a design<br />that reduces the resistance of the orifice plate as an<br />element of the pipeline. New forms of orifice plates, as well as a standard shape, which served as a reference, were tested according to the present algorithm. In the first step, orifice plates are designed in the Solid Works software package. Then, according to the proposed algorithm, they were tested using computer simulation in COMSOL Multiphysics software package. After achieving satisfactory results of computer simulation, orifice plates are made on a 3D printer, using the FDM process and tested in the laboratory apparatus. The results of laboratory tests were compared with the results of computer simulations. Compared results of computer simulation and laboratory testing showed that computer simulation described the situation well. The results of the laboratory test showed a significant energy-saving effect. It was also found that computer simulation can obtain data that can decide whether a new form of orifice plate must be corrected or it makes sense to access laboratory testing. The algorithm proposed in this doctoral dissertation has proven effective.</p>

Le travail présenté dans ce manuscrit concerne la fabrication de fantômes d'aorte patient spécifiques utilisant une technique de fabrication additive par impression 3D. Ces répliques sont fabriquées en matériaux synthétiques dont les caractéristiques morphologiques et les propriétés mécaniques doivent être proches de celles déterminées sur un patient. Elles permettent d'optimiser ou de développer les techniques d'imagerie médicale, de comprendre les relations entre le comportement mécanique de la paroi aortique et les caractéristiques hémodynamiques du flux sanguin mais aussi de réaliser des entrainements préopératoires aux interventions chirurgicales, telles que le traitement endovasculaire. Dans cette étude, le comportement mécanique hyper-viscoélastique de la paroi aortique est modélisé par un modèle de Maxwell solide généralisé, dont les paramètres ont permis la sélection et le développement de matériaux élastomères de type silicone aux comportements mécaniques contrôlés. Ces matériaux ont été élaborés à partir de mélanges de formulations existantes et des lois de mélange ont été comparées pour guider la définition de la composition idéale permettant d'imiter le comportement mécanique désiré. Nous avons mis au point une méthode basée sur l'imagerie médicale par ultrason, capable d'identifier les paramètres hyper-viscoélastiques d'une paroi vasculaire. Cette méthode a été validée sur des tubes réalisés avec ces formulations de silicone, dont les propriétés mécaniques ont été mesurées avec des méthodes de référence. Puis, ces silicones ont été utilisés dans un processus de fabrication additive utilisant l'impression 3D par voie indirecte. Un travail de conception assistée par ordinateur a été réalisé pour produire un fantôme d'aorte patient-spécifique présentant un anévrisme fusiforme et non-thrombosé dans la région thoracique / The present work deals with the producing of patient-specific aortic phantoms using an additive manufacturing technique by 3D printing. Phantoms are manufactured from synthetic materials with morphological and mechanical characteristics which should be close to these identified on a patient. They can be used to develop techniques of medical imaging, to understand the relationship between aortic mechanical behavior and hemodynamic properties of blood flow, as well as to perform a preoperative training of interventions, such as endovascular treatment. In this study, the hyper-viscoelastic aortic mechanical behavior was described using a generalized solid Maxwell model. Silicone materials were developed based on the model’s mechanical parameters to mimic various aortic mechanical behaviors. These materials were formulated from commercials silicones, and then mixing rules were compared to define the ideal mixture which can mimic the specific mechanical behavior. A nondestructive method based on medical imaging by ultrasound was developed to identify the parameters of a blood vessel hyper-viscoelastic model. Silicone tubes made of our formulations with known reference mechanical parameters, were used to validate this method. Then, these silicone materials were used in an additive manufacturing process using indirect 3D printing. A work of computer aided design was done to produce a patient-specific aortic phantom with a thoracic fusiform aneurysm without thrombosis

Subject of dissertation was to itemize testing methods in fresh and hardened state of cement paste or concrete. During this process some new testing methods and specimen creation protocols were proposed. Further was created list of used materials and mix design processes which led to list of used 3D printing mixture designs and 3D printers. Next part of dissertation was devoted to creation of 3D printing mix design and observations based on them. At~the end is proposed a radical change in testing methods which utilizes latest advancements in computer science and could be part of digital design process for construction.

This thesis covers the topic of controlling RC servos and constructions of robotic vehicles. The goal is to propose a model of robotic vehicle with RC components and other off the shelf components, 3D printing and demonstrate its capabilities. In the thesis, a mobile robot platform was proposed. It uses a single-board computer together with readily available parts and does not require complicated assembly. An optimization algorithm was used for the design of rack and pinion steering. The result of the thesis is the implementation of a robotic vehicle.

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No description available.

Collecting memorabilia has been a longstanding practice as it evolved around cultures and societies. Despite existing research about preserving memorabilia, meaningful preservation methods remain unclear due to the individual and idiosyncratic nature of practices [18,22,40,43,47,59]. Migrants who collect memorabilia face challenges in preserving them due to unavoidable circumstances such as lack of transportation, physical measurements and weight of memorabilia. In 2020, 281 million people migrated globally, accounting for 3.6% of the world's population, and as this issue continues to grow, finding practical solu tions is crucial [36,38]. The aim of this study is to explore ways to digitally preserve memorabilia to maintain their material qualities and meaning across diverse geographical contexts (RQ1). The study also focused on understanding what objects migrants regard as worth preserving (RQ2) and how digital memorabilia can be designed to serve as memory tokens (RQ3). The research employed an exploratory case study approach, focusing on first-generation Sri Lankan migrants [11,30]. Qualitative data was collected through interviews and the use of 3D printing and augmented reality was evaluated through prototype testing using a research-through-design approach [29,58]. Results revealed that souvenirs encapsulates sentimental, economic and aesthetic values that provides a symbolic meaning to its’ owner and contributes to constructing their identity. Migrants were willing to try new technologies and augmented reality was recognised as a satisfying experience. To transfer memorabilia meaningfully among different geographical context, a holistic solution for memorabilia preservation was expected by migrants where physical protection of memorabilia is emphasized. Further research in this study involves utilizing photogrammetry scanning and 3D modeling to closely replicate real-life memorabilia and further evaluating mixed-reality user interactions such as augmented reality.

This study has looked at two separate locations, Malmö in Sweden, and Medellin in Colombia, and what the possibilities of rainwater harvesting are in those locations. The paper investigated data gathered by low-cost sensors in Malmö region, as well as sampling and measurements of rainwater collected in Malmö and Medellin, analysed by laboratories in both countries. Important data for the paper are quantity, quality, as well as environmental benefits and the economical perspective of rainwater harvesting. There are several steps that can be taken towards a more sustainable use of the Earth’s resources, and rainwater harvesting is included in the possibilities already at hand. But there is need for further development of monitoring and ways to qualify water for different purposes. It is possible to utilize rainwater for many things, and with that, ease the pressure on the local water supply infrastructure. This study has shown some important parts of that process, and that even low-cost sensors can help in gathering essential data for further evaluation of the usability of the rainwater. By collecting parts of the rainwater, flooding due to extensive downpour can be mitigated to some extent. Moreover, considering the low price of the sensors tested in this study, it is possible to use several low-cost sensors to determine the usability to some extent. Had the measurements rendered in values being too low compared to the laboratory results, the risk would have been greater. The consequence is that usable water could be regarded as not usable since the sensors returned an overall higher value compared to the laboratory results. Furthermore, the research found that the environmental benefit can be substantial. But there are more positive implications when gathering water for usage locally. For example, the water supply can become more distributed and with that, less prone to cause events such as water leaks, polluted water, and extreme events that have rendered an unserviceable infrastructure.