The Leading-Edge Structure Based on Geometric Bionics Affects the Transient Cavitating Flow and Vortex Evolution of Hydrofoils

A hydrofoil is a fundamental structure in fluid machinery, and it is widely applied to the fields of propellers, blades of axial flow pumps and underwater machinery. To reveal that the geometric structure of the leading-edge of a hydrofoil is the mechanism that affects the transient cavitating flow, we regard the three fish-type leading-edge structures of mackerel, sturgeon and small yellow croaker as the research objects and use high-precision non-contact 3D scanners to establish three bionic hydrofoils (Mac./Stu./Cro.). We use large eddy simulation to simulate the transient cavitating flow of hydrofoils numerically and compare and analyze their lift–drag characteristics, the transient behavior of unsteady cavitation and the vortex evolution. The numerical simulation results are in good agreement with the experimental results. The warping of leading-edge structure will cause a change in lift–drag characteristics, and the Cro. hydrofoil has a good lift-to-drag ratio. When the leading-edge structure is tilted upward (Cro. hydrofoil), the position of the attached cavity will move forward, which will accelerate the cavitation evolution and improve the velocity fluctuation of the trailing edge. When the leading-edge structure is tilted downward (Stu. hydrofoil), the change in the vortex stretching and dilatation terms will be complex, and the influence area of the vortex will widen.

A Comparative Study between Scanning Devices for 3D Printing of Personalized Ostomy Patches

This papers presents a comparative study of three different 3D scanning modalities to acquire 3D meshes of stoma barrier rings from ostomized patients. Computerized Tomography and Structured light scanning methods were the digitization technologies studied in this research. Among the Structured Light systems, the Go!Scan 20 and the Structure Sensor were chosen as the handheld 3D scanners. Nineteen ostomized patients took part in this study, starting from the 3D scans acquisition until the printed ostomy patches validation. 3D mesh processing, mesh generation and 3D mesh comparison was carried out using commercial softwares. The results of the presented study show that the Structure Sensor, which is the low cost structured light 3D sensor, has a great potential for such applications. This study also discusses the benefits and reliability of low-cost structured light systems.

3D-volldigitalisierte Behandlungsplanung bei Lippen-Kiefer-Gaumenspalten (LKGS-3D)

Die Idealvorstellung eines vollständig digitalisierten Behandlungsalltags rückt mit fortschreitender technologischer und informationeller Entwicklung stetig näher an die Realität. Zu Beginn bestand lediglich die Möglichkeit einer elektronischen Patientenakte, hinzu kamen vielfältige Möglichkeiten der digitalen Bildgebung und wurden schließlich um das Ziel eines vollständigen digitalen Workflows ergänzt. Die Planung der interdisziplinären kieferorthopädischen / kieferchirurgischen Versorgung von Patienten mit Lippen-Kiefer-Gaumen-Spalten (LKGS) wurde bis vor kurzem am Universitätsklinikum Dresden noch hauptsächlich analog durchgeführt. Eine volldigitalisierte Behandlungsplanung unter Einbeziehung aller beteiligten Behandler fand nicht statt. Ziel des Projektes war es deshalb, eine digitale Plattform zur interdisziplinären zahnmedizinischen Versorgung von LKGS-Patienten zu schaffen. Dazu wurde zuerst die bisher erforderliche Abdrucknahme mittels Alginat und die anschließende Herstellung eines Gipsmodells durch einen intraoralen 3D-Scan der Zahnbögen des Patienten abgelöst. Anhand des intraoralen 3D-Scans können nun die erforderlichen Trinkplatten mittels 3D-Druck erstellt werden. Zweiter Schritt war die Anfertigung von 3D-Aufnahmen der Weichteile des Gesichtes mittels eines extraoralen 3D-Scanners. Als dritter Schritt erfolgte die Anfertigung von Digitalen Volumentomografie (DVT)-Aufnahmen zur 3D-Darstellung des Schädelknochens und Kieferskeletts. Nach der Anfertigung wurden diese bildbasierten Datensätze zu einem „digitalen Zwilling“ (virtuelles 3D-Modell aus DVT, intra- und extraoralen 3D-Scan) zusammengefasst, wodurch erstmalig ein umfassendes 3D-Modell des Mund-Kiefer-Raumes einschließlich wichtiger Informationen zum Kiefergelenk und der anliegenden Weichteile entstand. Dieses virtuelle Modell bildet jetzt die Grundlage für die Behandlungsplanung und die Planung der weiteren zahnmedizinischen und medizinischen Versorgung. Es konnte also im Projekt die komplette Digitalisierung der Diagnostik, die Etablierung einer Fusionsplattform und der Datenaustausch zwischen Uniklinik und privater Praxis umgesetzt werden.

Metadata schema and ontology for capturing and processing of 3D cultural heritage objects

Motivated by the increased use of 3D acquisition of objects by cultural heritage institutions, we were investigating ontologies and metadata schemes for the acquisition process to provide details about the 3D capturing, which can be combined with preexisting ontologies describing an object. Therefore we divided the 3D capturing workflow into common steps starting with the object being placed in front of a 3D scanner to preparation and publication of the 3D datasets and/or derived images. While the proposed ontology is well defined on a coarse level of detail for very different techniques, e.g. Stucture from Motion and LiDAR we elaborated the metadata scheme in very fine detail for 3D scanners available at our institutions. This includes practical experiments with measurement data from past and current projects including datasets published at Zenodo as guiding examples and the source code for their computation. Additionally, the free and Open Source GigaMesh Software Framework’s analysis and processing methods have been extended to provide metadata about the 3D processing steps like mesh cleaning as well as 2D image generation. Finally, we discuss the current limitations and give an outlook about future extensions.

3D Dead

Humans have interacted with the remains of our dead for aesthetic and ritual purposes for millennia, and we have utilized them for medical, educational, and scholarly pursuits for several centuries. Recently, it has become possible to use digital technologies such as 3D scanners and printers for reconstructing, representing, and disseminating bodies. At the same time, there is growing interest among academics and curators in taking a more reflexive approach to the ethical and social dimensions of conservation. This paper considers theoretical and practical aspects of ethics as they apply to the 3D scanning and printing of human skeletal remains for curation or dissemination, provides case studies from our work in the United States, and suggests guidelines for best practices. Los seres humanos hemos interactuado con los restos humanos de nuestros muertos por razones estéticas y rituales por milenios. Asimismo, estos restos han sido utilizados para conducir investigaciones médicas, educativas, y académicas por varios siglos. Recientemente, con la ayuda de la tecnología digital de los escáneres e impresoras 3D ha sido posible reconstruir, representar, y difundir estos cuerpos. Al mismo tiempo, los académicos y los conservadores proponen ser más reflexivos al lidiar con las dimension eséticas y sociales del campo de la conservación. Este artículo considera los aspectos teóricos y prácticos de la ética de los escaneos e impresiones 3D de restos óseos humanos para su conservación y diseminación, aporta casos prácticos de nuestros trabajos investigativos en los Estados Unidos como ejemplos, y sugiere normas para una práctica adecuada.

Scanning of Historical Clothes Using 3D Scanners: Comparison of Goals, Tools, and Methods

Due to the UN and EU’s strong interest in digitizing cultural heritage, the application of 3D scanning technology is gaining importance, even in the case of under-explored areas, such as the 3D scanning of historical clothes. This article discovers and compares methodologies of 3D scanning of historical clothes presented in the literature in order to determine if a new methodology is needed. PRISMA protocol was used to browse scientific sources in an organized way. We posed the following research question: How have 3D scanners been used to digitize historical clothes? The very limited number of works identified, despite our thorough search, allows us to conclude that this topic is very new, and a lot of research can be conducted in the future. We analyzed the methodologies proposed by other authors, taking into account factors such as what was scanned, what was the purpose of scanning, what hardware and software was used, how detailed the description was, etc. It was revealed that other authors explored the topic insufficiently and no complex and coherent methodology of 3D digitization of historical clothes is present. Generally, the field of 3D scanning of historical clothing remains, at this point, very small and fragmented. This work is one of steps to change it.

Structured-light 3D scanning of exhibited historical clothing—a first-ever methodical trial and its results

Historical costumes are part of cultural heritage. Unlike architectural monuments, they are very fragile, which exacerbates the problems of their protection and popularisation. A big help in this can be the digitisation of their appearance, preferably using modern techniques of three-dimensional representation (3D). The article presents the results of the search for examples and methodologies of implementing 3D scanning of exhibited historical clothes as well as the attendant problems. From a review of scientific literature it turns out that so far practically no one in the world has made any methodical attempts at scanning historical clothes using structured-light 3D scanners (SLS) and developing an appropriate methodology. The vast majority of methods for creating 3D models of clothes used photogrammetry and 3D modelling software. Therefore, an innovative approach was proposed to the problem of creating 3D models of exhibited historical clothes through their digitalisation by means of a 3D scanner using structural light technology. A proposal for the methodology of this process and concrete examples of its implementation and results are presented. The problems related to the scanning of 3D historical clothes are also described, as well as a proposal how to solve them or minimise their impact. The implementation of the methodology is presented on the example of scanning elements of the Emir of Bukhara's costume (Uzbekistan) from the end of the nineteenth century, consisting of the gown, turban and shoes. Moreover, the way of using 3D models and information technologies to popularise cultural heritage in the space of digital resources is also discussed.

Comparison of Body Scanner and Manual Anthropometric Measurements of Body Shape: A Systematic Review

Anthropometrics are a set of direct quantitative measurements of the human body’s external dimensions, which can be used as indirect measures of body composition. Due to a number of limitations of conventional manual techniques for the collection of body measurements, advanced systems using three-dimensional (3D) scanners are currently being employed, despite being a relatively new technique. A systematic review was carried out using Pubmed, Medline and the Cochrane Library to assess whether 3D scanners offer reproducible, reliable and accurate data with respect to anthropometrics. Although significant differences were found, 3D measurements correlated strongly with measurements made by conventional anthropometry, dual-energy X-ray absorptiometry (DXA) and air displacement plethysmography (ADP), among others. In most studies (61.1%), 3D scanners were more accurate than these other techniques; in fact, these scanners presented excellent accuracy or reliability. 3D scanners allow automated, quick and easy measurements of different body tissues. Moreover, they seem to provide reproducible, reliable and accurate data that correlate well with the other techniques used.