8 research outputs found

    Beyond the walls: the design and development of the Petralona Cave virtual museum utilising 3D technologies

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    The Petralona Cave, which local inhabitants discovered by chance in 1959, is a remarkable natural and cultural landmark close to the village of Petralona, in the Chalkidiki peninsula of Greece. The site has gained global recognition for the discovery of a remarkably well-preserved Palaeolithic human skull, unearthed in 1960; it also holds archaeological and palaeontological significance. In this paper, the researchers introduce the Petralona Cave Virtual Museum: an innovative project whose mission is to increase public awareness and comprehension of the site. Our approach goes beyond mere replication of the physical museum located close to the cave; instead, the objective is to create an independent and comprehensive experience that is accessible to all visitors, irrespective of their ability to visit the site in person. Our methodology involved the documentation of the site and its history, analysis of user requirements, development of use cases to steer the design process, as well as architectural designs creation, itineraries and findings digitisation, and architectural structure finalisation. The Virtual Museum provides a well-organised frame structure that serves as an efficient gateway to the content, making navigation easy for visitors. Thanks to various presentation methods, including videos, high-quality images, interactive maps, animated content, interactive 3D models, plus searchable item libraries, among others, users are empowered to create a highly personalised navigation plan; thus the Virtual Museum experience is comparable to visiting the physical museum or cultural site. Cutting-edge digitisation techniques were employed to create highly detailed 3D models of the site. The Petralona Cave Virtual Museum is expected to offer an immersive experience, engaging diverse audiences; the interactive and educational exploration provides highly innovative access to archaeological knowledge. The visibility of the Petralona site is amplified and there is a significant contribution to knowledge dissemination about this important cultural heritage site

    Parametric Design and Mechanical Characterization of 3D-Printed PLA Composite Biomimetic Voronoi Lattices Inspired by the Stereom of Sea Urchins

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    The present work is focused on the analysis of the microstructure of the exoskeleton of the sea urchin Paracentrotus lividus and the extraction of design concepts by implementing geometrically described 3D Voronoi diagrams. Scanning electron microscopy (SEM) analysis of dried sea urchin shells revealed a foam-like microstructure, also known as the stereom. Subsequently, parametric, digital models were created with the aid of the computer-aided design (CAD) software Rhinoceros 3D (v. Rhino 7, 7.1.20343.09491) combined with the visual programming environment Grasshopper. Variables such as node count, rod thickness and mesh smoothness of the biologically-inspired Voronoi lattice were adapted for 3D printing cubic specimens using the fused filament fabrication (FFF) method. The filaments used in the process were a commercial polylactic acid (PLA), a compound of polylactic acid/polyhydroxyalkanoate (PLA/PHA) and a wood fiber polylactic acid/polyhydroxyalkanoate (PLA/PHA) composite. Nanoindentation tests coupled with finite element analysis (FEA) produced the stress–strain response of the materials under study and were used to simulate the Voronoi geometries under a compression loading regime in order to study their deformation and stress distribution in relation to experimental compression testing. The PLA blend with polyhydroxyalkanoate seems to have a minor effect on the mechanical behavior of such structures, whereas when wood fibers are added to the compound, a major decrease in strength occurs. The computational model results significantly coincide with the experimental results

    Mechanical and FEA-Assisted Characterization of 3D Printed Continuous Glass Fiber Reinforced Nylon Cellular Structures

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    The main objective of this study was to investigate the mechanical behavior of 3D printed fiberglass-reinforced nylon honeycomb structures. A Continuous Fiber Fabrication (CFF) 3D printer was used since it makes it possible to lay continuous strands of fibers inside the 3D printed geometries at selected locations across the width in order to optimize the bending behavior. Nylon and nylon/fiberglass honeycomb structures were tested under a three-point bending regime. The microstructure of the filaments and the 3D printed fractured surfaces following bending tests were examined with Scanning Electron Microscopy (SEM). The modulus of the materials was also evaluated using the nanoindentation technique. The behavior of the 3D printed structures was simulated with a Finite Element Model (FEM). The experimental and simulation results demonstrated that 3D printed continuous fiberglass reinforcement is possible to selectively adjust the bending strength of the honeycombs. When glass fibers are located near the top and bottom faces of honeycombs, the bending strength is maximized

    3D printed hollow microneedles for transdermal insulin delivery

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    Microneedles (MN) are miniature devices of a maximum length of 1000 μm, capable of perforating painlessly stratum corneum and releasing their active content in the skin layers beneath. The significance of MNs lies on the fact that they have the potential to substitute the fear inducing injections, while avoiding first pass effect or other possibly unwished metabolic changes of the oral administration1. In the current study 3D printed microneedles were fabricated by means of liquid crystal display (LCD) vat polymerization 3D printing technology for the transdermal delivery of human insulin in vitro.In the current study the structural features of two different 3D printed 6x6 HMN geometries were assessed. Non-destructive 3D (volumetric) imaging by means of μCT demonstrated that the 3D printing method used in this study allows for high consistency and reproducibility with respect to needles’ geometric characteristics. Diffusion studies demonstrated that syringe-like HMNs were more effective upon insulin administration compared with curved pyramid ones. Although syringe-like geometry penetrates skin at higher insertion force, it is probably more suitable for macromolecular drug delivery which might be attributed to the geometrical characteristics of the microneedles

    Transdermal delivery of insulin across human skin in vitro with 3D printed hollow microneedles

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    In the current study hollow microneedles (HMNs) were fabricated by means of vat polymerization method for the transdermal delivery of insulin. Two geometries of HMNs were designed in a Computer Aided Design (CAD) software namely, curved pyramid and syringe-like and fabricated with Liquid Crystal Display (LCD) method. Dimensions were determined and quality features were imaged with scanning electron microscopy (SEM). Volumetric characterization of HMNs and microchannels was performed by microfocus computed tomography (ÎĽCT) whereas mechanical characterization and skin penetration tests of the two geometries were carried out both experimentally and by Finite Element Analysis (FEA) simulation. Diffusion studies of insulin across full thickness human skin were performed in vitro using Franz diffusion cells. Insulin samples were analyzed with liquid chromatography-mass spectrometry (LC-MS). The results show that the transport might be affected by the shape of the microneedles

    Fabrication of 3D printed hollow microneedles by digital light processing for the buccal delivery of actives

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    In the present study, two different microneedle devices were produced using digital light processing (DLP). These devices hold promise as drug delivery systems to the buccal tissue as they increase the permeability of actives with molecular weights between 600 and 4000 Da. The attached reservoirs were designed and printed along with the arrays as a whole device. Light microscopy was used to quality control the printability of the designs, confirming that the actual dimensions are in agreement with the digital design. Non-destructive volume imaging by means of microfocus computed tomography was employed for dimensional and defect characterization of the DLP-printed devices, demonstrating the actual volumes of the reservoirs and the malformations that occurred during printing. The penetration test and finite element analysis showed that the maximum stress experienced by the needles during the insertion process (10 N) was below their ultimate compressive strength (240-310 N). Permeation studies showed the increased permeability of three model drugs when delivered with the MN devices. Size-exclusion chromatography validated the stability of all the actives throughout the permeability tests. The safety of these printed devices for buccal administration was confirmed by histological evaluation and cell viability studies using the TR146 cell line, which indicated no toxic effects.</p