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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.

Nowadays, H13 hot work steel is a commonly used hot work die material in the industry; however, its creep behavior for additively manufactured H13 steel parts has not been widely investigated. This research paper examines the impact of volumetric energy density (VED), a critical parameter in additive manufacturing (AM), and the effect of post heat-treatment nitrification on the creep behavior of H13 hot work tool steel, which is constructed through selective laser melting (SLM), which is a powder bed fusion process according to ISO/ASTM 52900:2021. The study utilizes nanoindentation tests to investigate the creep response and the associated parameters such as the steady-state creep strain rate. Measurements and observations taken during the holding phase offer a valuable understanding of the behavior of the studied material. The findings of this study highlight a substantial influence of both VED and nitrification on several factors including hardness, modulus of elasticity, indentation depth, and creep displacement. Interestingly, the creep strain rate appears to be largely unaltered by these parameters. The study concludes with the observation that the creep stress exponent (n) shows a decreasing trend with an increase in VED and the application of nitrification treatment.

The present paper investigates the mechanical behavior of a biomimetic Voronoi structure, inspired by the microstructure of the shell of the sea urchin Paracentrotus lividus, with its characteristic topological attributes constituting the technical evaluation stage of a novel biomimetic design strategy. A parametric design algorithm was used as a basis to generate design permutations with gradually increasing rod thickness, node count, and model smoothness, geometric parameters that define a Voronoi structure and increase its relative density as they are enhanced. Physical PLA specimens were manufactured with a fused filament fabrication (FFF) printer and subjected to quasi-static loading. Finite element analysis (FEA) was conducted in order to verify the experimental results. A minor discrepancy between the relative density of the designed and printed models was calculated. The tests revealed that the compressive behavior of the structure consists of an elastic region followed by a smooth plateau region and, finally, by the densification zone. The yield strength, compressive modulus, and plateau stress of the structure are improved as the specific geometric parameters are enhanced. The same trend is observed in the energy absorption capabilities of the structure while a reverse one characterizes the densification strain of the specimens. A second-degree polynomial relation is also identified between the modulus, plateau stress, and energy capacity when plotted against the relative density of the specimens. Distinct Voronoi morphologies can be acquired with similar mechanical characteristics, depending on the design requirements and application. Potential applications include lightweight structural materials and protective gear and accessories.

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.

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.

Child-appropriate dosage forms are critical in promoting adherence and effective pharmacotherapy in pediatric patients, especially those undergoing long-term treatment in low-resource settings. The present study aimed to develop orodispersible films (ODFs) for isoniazid administration to children exposed to tuberculosis. The ODFs were produced from the aqueous solutions of natural and semi-synthetic polymer blends using electrospinning. The spinning solutions and the resulting fibers were physicochemically characterized, and the disintegration time and isoniazid release from the ODFs were assessed in simulated salivary fluid. The ODFs comprised of nanofibers with adequate thermal stability and possible drug amorphization. Film disintegration occurred instantly upon contact with simulated salivary fluid within less than 15 s, and isoniazid release from the ODFs in the same medium followed after the disintegration profiles, achieving rapid and total drug release within less than 60 s. The ease of administration and favorable drug loading and release properties of the ODFs may provide a dosage form able to facilitate proper adherence to treatment within the pediatric patient population.