| 1. |
- Jué, Sarah, et al.
(författare)
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Enhancing wood UV stability: novel treatment strategies with citric acid and urea
- 2024
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Ingår i: Wood Material Science & Engineering. - : Taylor & Francis. - 1748-0272 .- 1748-0280. ; 19:4, s. 993-996
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Tidskriftsartikel (refereegranskat)abstract
- Wood, a fundamental material in construction, confronts durability and weathering challenges, notably UV-induced degradation leading to colour changes. This study investigated a novel treatment using citric acid and urea to enhance the UV stability of wood. The reaction between these compounds generates water-soluble fluorescent species and insoluble particles upon thermal treatment which may provide wood with UV protection. Specimens were treated with two different treatment methods and then exposed to 2016 h of accelerated weathering, during which colour was measured regularly. Citric acid and urea were either pressure impregnated into the wood and thermally reacted in situ during heat treatment or pre-reacted in the absence of wood with subsequent implementation into melamine formaldehyde (MF) and water-based surface coatings. The results showed that water-soluble fluorophore compounds were formed with both treatment methods. Accelerated weathering tests revealed significant colour changes over time, where specimens coated with a mixture of MF and fluorescent particles from the reaction between citric acid and urea, exhibiting the least alteration. The lowest colour change ΔE of 5.9 was observed for specimens coated with a MF-based coating containing 1 wt% of citric acid and urea thermally pre-reacted at a temperature of 180 °C, showcasing potential wood protection applications.
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| 2. |
- Kitek Kuzman, Manja, et al.
(författare)
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Produits d’Ingénierie en Bois pour l’Architecture Contemporaine : Cas d´étude
- 2018. - 1000
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Bok (refereegranskat)abstract
- Ce livre explore et illustre les utilisations de différents produits de bois d'ingénierie (PBI) contemporains et introduit de nouveaux matériaux à base de bois. Chaque page décrit un PBI spécifique illustré par des images éloquentes montrant différentes applications des PBI dans l'architecture et la construction intérieure et extérieure des bâtiments.Aucun matériau n'a été jadis aussi présent dans notre quotidien que le bois sous ses différentes formes. Les PBI présentent le lien entre la science du bois, l'ingénierie structurelle, l'architecture et la conception Le travail présenté est issu de la collaboration interdisciplinaire et des expériences diverses de trois chercheurs en bois de Slovénie, Suède et France, avec des compétences (i) en ingénierie du bois avec une expérience et une connaissance des besoins technologiques, (ii) en architecture avec une connaissance approfondie des besoins liés à la culture, (iii) en Génie civil et sciences du bois orientées vers l'environnement et la foresterie.Le but du livre est de promouvoir l'utilisation des PBI basées sur une technologie de haut niveau et un savoir-faire technique qui nécessite une réflexion créative, une vision globale et des points de vue philosophiques. En définitive, nous allons accroitre les connaissances inhérentes à l'utilisation du bois, atteindre l'excellence dans la formation et la conception des produits à base de bois. L'ouvrage sera utile aux concepteurs, aux architectes et aux experts dans leurs efforts continus pour une meilleure utilisation du bois dans la conception et la planification architecturale contemporaine. A titre d’exemple, une étude comparative de perception qu'ont les architectes français et gabonais sur les produits de bois d'ingénierie est proposée afin de donner plus d'informations à l'architecte et à l'ingénieur civil sur ces produits.
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| 3. |
- Nziengui, Claude Feldman Pambou, et al.
(författare)
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Experimental assessment of the annual growth ring’s impact on the mechanical behavior of temperate and tropical species
- 2020
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Ingår i: BioResources. - : NC State University. - 1930-2126. ; 15:2, s. 4282-4293
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Tidskriftsartikel (refereegranskat)abstract
- An innovative experimental protocol is presented, linking a nondestructive (on computed tomography scanner) and destructive approach (bending test on electrostatic press). This study aimed to evaluate the annual growth ring’s impact on the mechanical behavior of wood. The tests were carried out on temperate specimens (Pseudotsuga menziesii and Abies alba Mill) from the Massif Central Region of France and tropical specimens (Aucoumea klaineana Pierre, Milicia excelsa, and Pterocarpus soyauxii) from Gabon. The connection between the mechanical parameters, taken from these tests and their structural characteristics, are also highlighted. Based on these results, a database was formed of the annual growth ring’s impact on the mechanical characteristics of these species. A link was found between the annual growth ring and the mechanical and physical characteristics of the species. The number and width of the earlywood ring and its mechanical properties were also investigated for each type of species. This comparison and the link highlighted was possible due to the study of the impact of dry density’s specimens, considered in this work as an adjustment parameter on the study of the mechanical behavior of these species.
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| 4. |
- Rodrigues, Quentin, et al.
(författare)
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Using X-Ray Computed Tomography To Measure Fire Degradation Of A Timber Connection
- 2023
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Ingår i: World Conference on Timber Engineering (WCTE 2023). - Oslo : World Conference on Timber Engineering 2023 (WCTE 2023). ; , s. 1519-1525
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Konferensbidrag (refereegranskat)abstract
- The charring behaviour of timber elements under fire is well understood, however, the effects of fire and heat on connections are not equally well known. Timber connections often use steel fasteners, like screws or angle brackets, which conduct heat much better than wood. Moreover, these fasteners lose their mechanical resistance and capacity under elevated temperatures. X-ray computed tomography (CT) can be used to reconstruct the internal structure of wood non-destructively. It should therefore be possible to use this technology to also study the progressive degradation due to fire of a timber connection. The goal of the present study is to investigate how CT can be used to analyse the degradation of a timber connection due to fire. Samples of Norway spruce with self-tapping screws were scanned before and after a fire exposure, and mechanical tests were performed. The results indicate that the degradation due to fire in a timber connection can be observed in CT scans, but that certain measures need to be taken to minimise the effects of image artefacts due to X-ray scattering and photon starvation.
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