33 research outputs found

    High performance computing for modelling of stereolithography process

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    In this dissertation, a state-of-the-art 3D computational model has been developed for Stereolithography process to investigate the evolution of properties in a multi-physics framework using Stabilized Optimal Transportation Meshfree (OTM) method based on a continuum approach. In order to accelerate the computational performance, HPC framework of the OTM method has been developed. Stereolithography process is a complex process in the sense that several physical processes are involved therein. In this work, some of the key phenomena incorporated in the modeling framework are highly coupled thermo-chemo-mechanical evolution of resin properties and propagation of the UV laser through the resin. The photopolymerization is driven by the interaction of fluid resin with the UV light and consequently generates heat due to its exothermic nature and resulting in building up of mechanical stresses. The numerical and geometrical complexities arising from these phenomena pose serious challenges and complications in grid-based techniques such as Finite element (FE). Generally, such issues are referred to as mesh distortion. OTM based computational modeling is one solution to these issues. The method is quite new in the field of Stereolithography simulation and it is efficient in capturing the deformations generated during printing process. Moreover, parallelization using MPI with an objective for scalability on large scale CPU clusters reduces the computational efforts. And, the obtained results leads to highly scalable results. The developed tool can be employed to optimize the material and process parameters during the printing process to achieve improved accuracy in the printed parts

    The Origin and Early Evolution of Life

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    What is life? How, where, and when did life arise? These questions have remained most fascinating over the last hundred years. Systems chemistry is the way to go to better understand this problem and to try and answer the unsolved question regarding the origin of Life. Self-organization, thanks to the role of lipid boundaries, made possible the rise of protocells. The role of these boundaries is to separate and co-locate micro-environments, and make them spatially distinct; to protect and keep them at defined concentrations; and to enable a multitude of often competing and interfering biochemical reactions to occur simultaneously. The aim of this Special Issue is to summarize the latest discoveries in the field of the prebiotic chemistry of biomolecules, self-organization, protocells and the origin of life. In recent years, thousands of excellent reviews and articles have appeared in the literature and some breakthroughs have already been achieved. However, a great deal of work remains to be carried out. Beyond the borders of the traditional domains of scientific activity, the multidisciplinary character of the present Special Issue leaves space for anyone to creatively contribute to any aspect of these and related relevant topics. We hope that the presented works will be stimulating for a new generation of scientists that are taking their first steps in this fascinating field

    Application of mixed and virtual reality in geoscience and engineering geology

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    Visual learning and efficient communication in mining and geotechnical practices is crucial, yet often challenging. With the advancement of Virtual Reality (VR) and Mixed Reality (MR) a new era of geovisualization has emerged. This thesis demonstrates the capabilities of a virtual continuum approach using varying scales of geoscience applications. An application that aids analyses of small-scale geological investigation was constructed using a 3D holographic drill core model. A virtual core logger was also developed to assist logging in the field and subsequent communication by visualizing the core in a complementary holographic environment. Enriched logging practices enhance interpretation with potential economic and safety benefits to mining and geotechnical infrastructure projects. A mine-scale model of the LKAB mine in Sweden was developed to improve communication on mining induced subsidence between geologists, engineers and the public. GPS, InSAR and micro-seismicity data were hosted in a single database, which was geovisualized through Virtual and Mixed Reality. The wide array of applications presented in this thesis illustrate the potential of Mixed and Virtual Reality and improvements gained on current conventional geological and geotechnical data collection, interpretation and communication at all scales from the micro- (e.g. thin section) to the macro- scale (e.g. mine)

    Online learning of physics during a pandemic: A report from an academic experience in Italy

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    The arrival of the Sars-Cov II has opened a new window on teaching physics in academia. Frontal lectures have left space for online teaching, teachers have been faced with a new way of spreading knowledge, adapting contents and modalities of their courses. Students have faced up with a new way of learning physics, which relies on free access to materials and their informatics knowledge. We decided to investigate how online didactics has influenced students’ assessments, motivation, and satisfaction in learning physics during the pandemic in 2020. The research has involved bachelor (n = 53) and master (n = 27) students of the Physics Department at the University of Cagliari (N = 80, 47 male; 33 female). The MANOVA supported significant mean differences about gender and university level with higher values for girls and master students in almost all variables investigated. The path analysis showed that student-student, student-teacher interaction, and the organization of the courses significantly influenced satisfaction and motivation in learning physics. The results of this study can be used to improve the standards of teaching in physics at the University of Cagliar

    Simulating urban soil carbon decomposition using local weather input from a surface model

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    Non peer reviewe

    Commonalities in the emplacement of cooling-limited lavas:insights from the 2011-2012 Cordón Caulle rhyolitic eruption

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    Lava flows pose a risk to infrastructure and communities near many volcanoes. Although the emplacement processes of low-viscosity basaltic lava flows are relatively well studied, the infrequency of silicic eruptions has limited our understanding of the emplacement of high-viscosity rhyolitic lavas. The 2011-2012 eruption of Puyehue-Cordón Caulle in southern Chile provided a unique opportunity to make scientific observations of an active rhyolitic lava flow. The thesis utilises a multiscale approach to draw comparisons between the emplacement of mafic and silicic lavas by building on the established understanding of basaltic flows. The thesis demonstrates the similarities and differences in the emplacement of cooling-limited lavas at contrasting ends of the compositional spectrum. Observations and quantitative models of lava flow lengthening demonstrate that advance of the Cordón Caulle lava flow was controlled in its latter phases by a cooled surface crust, which suggests similarities to the rheological control of cooling-limited basaltic lava flows. Cessation in flow advance was followed by breakout formation, the first such observations in a rhyolitic lava flow. Breakout formation was triggered by a pressure build-up at the flow margins, due to continued supply of lava along preferential thermal pathways, as well as late stage vesiculation of the flow core. The breakouts developed a morphological range classified into domed, petaloid, rubbly and cleft-split, which reflect the results of advance and inflation processes. Many silicic lavas show pumice diapirs and crease structures at their surface, but such features were rarely observed at Cordón Caulle. The inferred strong surface crust of the Cordón Caulle lava flow, as well as higher viscosity than other rhyolite lava flows, may have locally impeded upwelling to the lava surface, so favouring breakout formation. Insights gained from Cordón Caulle will aid the interpretation of ancient silicic lava flows, and help anticipate the hazards posed by future eruptions of rhyolitic lava

    In conclusion

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