Advances in shape measurement in the digital world

The importance of particle shape in terms of its effects on the behaviour of powders and other particulate systems has long been recognised, but particle shape information has been rather difficult to obtain and use until fairly recently, unlike its better-known counterpart, particle size. However, advances in computing power and 3D image acquisition and analysis techniques have resulted in major progress being made in the measurement, description and application of particle shape information in recent years. Because we are now in a digital era, it is fitting that many of these advanced techniques are based on digital technology. This review article aims to trace the development of these new techniques, highlight their contributions to both academic and practical applications, and present a perspective for future developments

Advanced Knowledge Application in Practice

The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research

Métodos de representação virtual e visualização para informação arquitetónica e contextual em sítios arqueológicos

This work seeks to outline some guidelines in order to improve the use of 3D visualization applied to archaeological data of diverse nature and at different scales. One difficulty found in this process is related to the still frequent two-dimensional representation of the three-dimensional archaeological reality. Aware that the existence of data of two-dimensional nature is fundamental in the archaeological process and that they result, on the one hand, from the manual archaeological recording processes and, on the other hand, from the intense analysis and interpretation activity of the archaeological investigation team, we seek to ensure an adequate 3D representation based on 3D acquisition methods mostly available to the archaeology teams. Archaeological visualization in three-dimensional support is an increasingly frequent and necessary practice, but it continues to show some difficulties. These are substantiated in the reduced number of visualization techniques used, the use of visualization tools that are not very customized for the archaeological needs and the privileged use of visual features of the models during the archaeological process phases. Thus, the main objective of this work is to design and evaluate appropriate methods for visualizing archaeological data. To determine which visualization methods are most used during the phases of the archaeological process, an online user-survey was carried out, which allowed consolidating the 3D representation methodologies used, as well as to propose a visualization model that also categorizes the appropriate visualization techniques which increase the visual perception and understanding of the archaeological elements. Three prototypes are defined according to the different 3D data acquisition methodologies presented and visualization methodologies are designed in order to, on the one hand, take into account the scale and diversity of the archaeological elements and, on the other hand, to account for the need to ensure visualization methods which are easily assimilated by archaeologists. Each prototype was evaluated by two archaeologists with different professional background. They were proposed, through a set of previously determined tasks, to assess the interaction with 3D models and with the visualization methods and the satisfaction of the visualization results regarding the archaeological needs. The evaluation of the prototypes allowed to conclude that the presented visualization methods increase the perception of 3D models which represent archaeological elements. In addition, it was also possible to produce new objects that reveal elements of archaeological interest. It is suggested to make these methodologies available on a web-based application and on mobile platforms.Este trabalho procura esboçar algumas diretrizes no sentido de melhorar a utilização da visualização 3D aplicada aos dados arqueológicos de natureza diversa e a escalas distintas. Uma dificuldade encontrada neste processo prende-se com a, ainda frequente, representação bidimensional da realidade arqueológica tridimensional. Ciente de que a existência de dados de natureza bidimensional são fundamentais no processo arqueológico e que resultam, por um lado, dos processos manuais de registo arqueológicos e, por outro, da intensa atividade de análise e interpretação da equipa de investigação arqueológica, procuramos assegurar uma representação 3D adequada, com base em metodologias de aquisição de dados 3D geralmente disponíveis às equipas de arqueologia. A visualização arqueológica em suporte tridimensional é uma prática cada vez mais frequente e necessária, mas que continua a evidenciar algumas dificuldades. Estas substanciam-se no reduzido número de técnicas de visualização usadas, na utilização de ferramentas de visualização pouco adaptadas às necessidades arqueológicas e na utilização preferencial de características visuais dos modelos durante as fases do processo arqueológico. Assim, o objetivo primordial deste trabalho é desenhar e avaliar métodos adequados à visualização de dados arqueológicos. Para determinar que métodos de visualização são mais utilizados durante as fases do processo arqueológico realizou-se um questionário online que permitiu consolidar as metodologias de representação 3D usadas, bem como propor um modelo de visualização que também categoriza as técnicas de visualização adequadas para aumentar a perceção e a compreensão visual dos elementos arqueológicos. Definem-se três protótipos de acordo com as distintas metodologias de aquisição de dados 3D apresentados e são desenhadas metodologias de visualização que, por um lado, têm em conta a escala e a diversidade dos elementos arqueológicos e, por outro, a necessidade de assegurar métodos de visualização facilmente assimilados pelos arqueólogos. Cada protótipo foi avaliado por dois arqueólogos com experiências profissionais distintas. O que lhes foi proposto, através de um conjunto de tarefas previamente estabelecidas, foi aferir da facilidade de interação com os modelos 3D e com os métodos de visualização e adequação dos resultados de visualização às necessidades dos arqueólogos. A avaliação dos protótipos permitiu concluir que os métodos de visualização apresentados aumentam a perceção dos modelos 3D que representam elementos arqueológicos. Para além disso foi possível produzir também novos objetos que revelam elementos com interesse arqueológico. É sugerida a disponibilização destas metodologias em ambiente web e plataformas móveis.Programa Doutoral em Informátic

Research Reports: 1997 NASA/ASEE Summer Faculty Fellowship Program

For the 33rd consecutive year, a NASA/ASEE Summer Faculty Fellowship Program was conducted at the Marshall Space Flight Center (MSFC). The program was conducted by the University of Alabama in Huntsville and MSFC during the period June 2, 1997 through August 8, 1997. Operated under the auspices of the American Society for Engineering Education, the MSFC program was sponsored by the Higher Education Branch, Education Division, NASA Headquarters, Washington, D.C. The basic objectives of the program, which are in the 34th year of operation nationally, are: (1) to further the professional knowledge of qualified engineering and science faculty members; (2) to stimulate an exchange of ideas between participants and NASA; (3) to enrich and refresh the research and teaching activities of the participants' institutions; and (4) to contribute to the research objectives of the NASA centers. The Faculty Fellows spent 10 weeks at MSFC engaged in a research project compatible with their interests and background and worked in collaboration with a NASA/MSFC colleague. This document is a compilation of Fellows' reports on their research during the summer of 1997. The University of Alabama in Huntsville presents the Co-Directors' report on the administrative operations of the program. Further information can be obtained by contacting any of the editors

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

Modeling EMI Resulting from a Signal Via Transition Through Power/Ground Layers

Signal transitioning through layers on vias are very common in multi-layer printed circuit board (PCB) design. For a signal via transitioning through the internal power and ground planes, the return current must switch from one reference plane to another reference plane. The discontinuity of the return current at the via excites the power and ground planes, and results in noise on the power bus that can lead to signal integrity, as well as EMI problems. Numerical methods, such as the finite-difference time-domain (FDTD), Moment of Methods (MoM), and partial element equivalent circuit (PEEC) method, were employed herein to study this problem. The modeled results are supported by measurements. In addition, a common EMI mitigation approach of adding a decoupling capacitor was investigated with the FDTD method

Massiv parallele Simulation von Mehrphasen- und Mehrkomponentenströmungen unter Anwendung des Lattice Boltzmann Verfahrens

This thesis reflects the work mainly performed within the research project FIMOTUM focusing on the determination of transport properties and mechanisms in unsaturated media. The efficient simulation of single- and multiphase flows at the pore scale in highly resolved natural porous media is one of the major topics in this work. For this purpose a simulation kernel which is based on the lattice Boltzmann method (LBM) has been developed and extensively validated. The LBM presented utilizes the Multiple Relaxation Time (MRT) model and fluid/wall boundary conditions of second order accuracy. The model has also been extended to solve multiphase, advection/diffusion and thermal flow problems. Due to the application of an optimized collision model and corresponding boundary conditions, the covered parameter space and the stability of the method could be greatly enhanced. Hence, it was possible to perform simulations in complex geometries at a large scale (2E11+ DoF) which have been obtained with an unprecedented accuracy. A second target of this thesis was the design and implementation of a simulation kernel to perform massively parallel computations with high efficiency. In order to obtain accurate simulation results at reasonable computational effort, a novel grid generation procedure has been developed. The robust and flexible method is based on the decoupling of input geometry and the actual computational grid. It is therefore excellently suited for the grid generation based on natural porous media data sets obtained by CT- or X-ray methods. Aspects concerning the increasing difficulties in pre- and post-processing of large data sets are discussed. Furthermore, special issues in high performance computing environments are highlighted and a tool chain to visualize scientific data in photo-realistic representation is described.Die vorliegende Dissertation gibt im Wesentlichen die Arbeiten wieder, die im Rahmen des FIMOTUM Projektes durchgeführt worden sind, welches sich vornehmlich auf die Untersuchung von Transporteigenschaften in ungesättigten porösen Medien fokussierte. Hierfür wurde ein Software-Prototyp auf Basis der Gitter Boltzmann Methode (LBM) entwickelt und ausführlich validiert. Die vorgestellte LB-Methode basiert auf dem Multiple-Relaxation-Time (MRT) Modell und verwendet Fluid/Wand Randbedingungen mit einer Genauigkeit 2. Ordnung. Das beschriebene Modell wurde zudem für die Simulation von Mehrphasen-, Advektion/Diffusions- und Thermalen Problemen erweitert. Durch die Optimierung des Kollisionsmodells und der entsprechenden Randbedingungen konnte der nutzbare Parameterraum deutlich vergrößert werden, so dass Simulationen in komplexen Geometrien mit mehr als 2.0E+11 Freiheitsgraden möglich wurden. Ein zweites Ziel dieser Arbeit war die Implementierung eines effizienten und hochparallelen Software-Prototypen zur Simulation von fluiddynamischen Problemen. Um möglichst genaue Ergebnisse bei mäßigem Ressourceneinsatz zu erzielen, wurde ein neuartiger Gittergenerierungsprozess entwickelt. Dieses robuste und flexible Verfahren basiert auf der Entkopplung von Eingangsgeometrie und dem eigentlichen Rechengitter. Daher eignet sich dieser Gittergenerator hervorragend für die Erzeugung eines numerischen Gitters aus digitalen Datensätzen natürlicher poröser Medien, wie bspw. Tomographie-Scans. Desweiteren werden, neben allgemeinen Problemen des Hochleistungsrechnens, die zunehmenden Schwierigkeiten bei der Verarbeitung der ständig steigenden Datenmengen im Pre- und Postprocessing diskutiert. Weiterhin wird, unterstützend zur Ergebnisanalyse, eine Prozesskette für die Erzeugung von fotorealistischen Visualisierungen aus Simulationsdaten beschrieben