http://hdl.handle.net/20.500.11960/3795 Fri, 28 Aug 2026 00:45:39 GMT 2026-08-28T00:45:39Z http://hdl.handle.net/20.500.11960/5001 Title: Effects of different orientations and treatments in an outdoor natural aging of japanese cryptomeria and scots pine wood Authors: Almeida, Joana O.; Labrincha, António; Parauta, Helena; Fernandes, Fábio; Delgado, Pedro Abstract: Wood is an excellent material in terms of sustainability; however, for durability reasons, it is critical to understand its aging over time, especially in outdoor spaces. Maximizing the lifespan of outdoor timber requires identifying the primary drivers of early-stage deterioration. This understanding ensures the selection of the most effective treatment and maintenance strategies. For this purpose, a natural aging exposure test was conducted on 32 samples of Cryptomeria wood and Scots pine, with 4 different solar orientations and 4 treatments, in a coastal area. To assess material behavior during the early stages of exposure without maintenance intervention, degradation was recorded over the initial 2 years of exposure. Those records were made based on visual analyses and classification tables for abiotic and biotic degradation, complemented by colorimetry to determine the specific effects of UV-induced photodegradation. The results obtained underline the importance of anti-tannin impregnation in the treatment process and demonstrate that treated pine wood shows greater color variations than treated Cryptomeria wood. This study reaffirms the indispensability of wood protection systems and suggests that reapplication must occur early in the service life to mitigate initial deterioration. Tue, 30 Jun 2026 00:00:00 GMT http://hdl.handle.net/20.500.11960/5001 2026-06-30T00:00:00Z http://hdl.handle.net/20.500.11960/4876 Title: Synergistic effect of high-energy milling and organic intercalation on the kaolin properties and structural evolution Authors: Zaccaron, Alexandre; Raupp-Pereira, Fabiano; Nandi, Vitor de Souza; Abrantes, João C.C.; Ribeiro, Manuel J.; Bernardin, Adriano Michael Abstract: Clays are raw materials with a wide range of applications in modern times. They can be used in various industrial applications, from the simplest to the most technological, such as in the ceramic industry to functionalizing components for the intercalation of organic molecules into polymeric matrices. Kaolinitic clays with a 1:1-layer structure is among the most abundant in the Earth's crust and are relatively easy to extract. Therefore, studies aimed at expanding the range of applications through the modification of the microstructure of these clay minerals have increasingly attracted scientific attention. The microstructural alteration of kaolinite through high-energy mechanical action can be an interesting method for mineral functionalization, as it leads to an increase in specific surface area and, consequently, the reactivity of the inorganic solid component. For this reason, this study investigated the effectiveness of the mechanical transformation process using high-purity kaolin, characterized before and after the high-energy milling process using XRF, XRD, DTA/TG, PSD, FTIR, and SEM techniques. The results showed that the milling process significantly altered the kaolinitic microstructure, demonstrating a reduction in particle size under the established experimental conditions, reaching D90 ≤ 1 μm. By obtaining a reactive solid with a significantly increased specific surface area (18× increase through milling), a 2k factorial experimental design was applied to study some variables of the intercalation process, such as the type of molecule (diaminomethanal - urea and dimethyl sulfoxide - DMSO), stirring time (from 12 to 24 h), and kaolinite mass (varying from 10 to 50 g) in a 100 mL solution. The microstructural characterization results via XRD revealed that the use of DMSO resulted in better efficacy in increasing basal spacing (from 7.2 Å to 11.3 Å with DMSO) and consequently in a possible application with functional groups. Wed, 01 Jan 2025 00:00:00 GMT http://hdl.handle.net/20.500.11960/4876 2025-01-01T00:00:00Z http://hdl.handle.net/20.500.11960/4875 Title: Technology overview and investigation of the quality of a 3D-printed maraging steel demonstration part Authors: Vasques, César; Cavadas, Adélio; Abrantes, João C. C. Abstract: Additive manufacturing (AM) has gained significant traction in the production of high-performance metallic components, yet concerns persist regarding the consistency of powder materials and the mechanical properties of 3D-printed parts. This study addresses these challenges through a detailed analysis of a maraging steel part manufactured using laser powder bed fusion. The demonstration part was evaluated for geometric accuracy, surface roughness, chemical composition, microstructure, and mechanical properties, including hardness and density. The findings revealed that 3D-printed maraging steel components can achieve high levels of dimensional precision and mechanical integrity, making them suitable for demanding applications. Despite these promising results, the study highlighted the need for improved powder quality control and accurate composition measurement to ensure the consistent production of reliable parts. The non-destructive hardness testing method applied in this study proved effective for predicting tensile strength, offering a streamlined approach to quality assurance. These results contribute to a growing body of research and knowledge supporting the adoption of AM for producing critical mechanical components, while underscoring the need for further investigation into quality assurance and standardized non-destructive testing procedures for high-performance metal AM parts. Wed, 01 Jan 2025 00:00:00 GMT http://hdl.handle.net/20.500.11960/4875 2025-01-01T00:00:00Z http://hdl.handle.net/20.500.11960/4869 Title: Additive manufacturing integrated technologies applied to human machine interfaces: An industry 5.0 overview Authors: Rahmani, Ramin; Karimi, Javad; Davoodi, Farideh; Abrantes, João C.C.; Resende, Pedro R.; Lopes, Sérgio I. Abstract: The industry 5.0 revolution prioritizes digital transformation and automation, while also focusing on improving human-machine interface (HMI), improving production and reducing work-related injuries. On the other hand, to tackle the challenge of designing lightweight and complicated structures, new high-tech materials have been developed using combined additive manufacturing (AM) and powder metallurgy (PM) techniques. The futuristic subsections of additive manufacturing (AM) produce composite materials that incorporate both metallic and ceramic components, suitable for a range of applications from art to industrial use. This brief overview examines the key features of the fifth industrial revolution, with particular attention to the selective laser melting (SLM) process. Two specific areas of study include the exploration of an antiviral metal-ceramic composite and also reflective metal fabrication using integrated AM-PM technologies. Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.11960/4869 2023-01-01T00:00:00Z