Alade Adefemi AdebisiWessels Coenraad BrandStolze HannesMilitz Holger...
9页
查看更多>>摘要：ABSTRACT The prospect of manufacturing durable structural laminated wood with copper and boron-based preservative-impregnated Eucalyptus grandis wood was previously investigated but revealed adhesive-bond performance below standard requirements. In this study, bonding process factors, viz. mechanical pretreatment (surface planing) and bonding pressure in conjunction with wood preservative and adhesive compatibility for improved bond performance in preservative-treated E. grandis laminates were investigated. The results obtained showed significant and satisfactory improvement in shear strength and delamination resistance of E. grandis laminates based on EN 14080:2013 [Timber structures — Glued laminated timber and glued solid timber — Requirements, BSI Stand. Publ. (2014) 1–110] requirements. The suitability of polyurethane, melamine-urea-formaldehyde, and phenol-resorcinol-formaldehyde adhesives for bonding copper azole (CA) and disodium octaborate tetrahydrate (DOT)-impregnated E. grandis wood was established. Satisfactory pathways, including greener process routes for manufacturing CA and DOT-impregnated E. grandis laminates for structural applications in tropical and subtropical climes were achieved. The established processes could be readily adopted industrially to enhance the global implementation of solid wood composites and promote hardwood bonding.
Jahan TarannumLekhak BrijeshVerma A. K.Dubey Ashutosh...
8页
查看更多>>摘要：ABSTRACT The pine needles bio-oil was partially replaced with phenol-formaldehyde (PF) resin at a rate of up to 40% by weight. The wood adhesive characteristics of a newly produced bio-oil phenol-formaldehyde (BOPF) resin with 10% bio-oil replacements was found to be comparable to those of pure PF resin with similar shear strength. DSC revealed that the curing temperature of 20 wt-% BOPF resin decreased from 95 to 60°C. Thermal degradation of BOPF resins was somewhat lower than that of pure PF resin, according to TGA and DTG data, and was similar in 10 and 20 wt-% BOPF resins. The presence of methylene bridges between phenols shown by FTIR analysis indicated that the wood adhesive had a good quality. According to SEM examination, the 10 and 20% BOPF resins showed a flat microstructure comparable to the pure PF resin.
查看更多>>摘要：ABSTRACT Assessing intrinsic wood qualities such as modulus of elasticity and internal decay in trees and logs can be challenging. However, acoustic technologies have been investigated for a possible solution. This paper reviews available literature on non-destructive acoustic methods for assessing wood quality, both in tree and log form. The paper further reviews the effects of silvicultural practices (such as thinning and pruning) on wood quality assessed by non-destructive acoustic methods. We documented some of the benefits of application of non-destructive acoustic methods on wood quality of trees and logs. The acoustic velocity of a tree (VT) or log (VL) of the propagated waves and wood density can be used to determine the Dynamic Modulus of Elasticity (MOEd). Thinning was reported to affect VT/VL and MOEd negatively. Acoustic tomography methods were equally found to have good accuracy in detecting the location and extent of wood decay in standing trees and logs.
Dadzie Peter KesselsAmoah MartinInkum Paul BenedictBoampong Ernest...
14页
查看更多>>摘要：ABSTRACT This study sought to appraise 7-year and 9-year-old Cedrela odorata for pulp and paper making. Sectioning and maceration processes were adopted. Data were subjected to statistical analysis using SPSS version 17.00. Cell characteristics for all ages and tree positions appeared similar but quantitatively, cells in 9-year-old generally exhibited some significant (p?<?.05) variations. Age and wood position generally had some significant influence on cell characteristics. Fibre lengths were generally short (<1.6?mm or 1600?μm) with variations in fibre morphology being significant axially than radially. In appraising the wood for paper production, derived fibre indices/values viz; Runkel ratio (ranging from 0.19 to 0.28), flexibility coefficient (ranging from 0.78 to 0.83), and slenderness ratio (ranging from 38.98 to 51.72) appeared to provide some positive indications. The species therefore, has potential for pulp and paper production, but further studies on its chemical consumption levels and other properties need to be ascertained towards a well-informed decision.
查看更多>>摘要：ABSTRACT The absence of an established design load constitutes a challenge to the engineering design of classroom furniture. This study developed a methodology for estimating design loads for single user (SU) and multiple user (MU) wooden classroom chair and desk combinations offered to secondary school students in Ibadan, Oyo State, Nigeria. Service load distribution patterns for the chair and desk members in normal, backward and front-reclining sitting postures were determined for 15 girls and 15 boys using bathroom scales. A T-test was used to compare the significance of the means of the proportions of users’ weights transferred to the chair and the floor. Design loads were 1 kN (SU) and 2.7 kN (MU) for chair and desk configurations, respectively. Each SU and MU leg should be designed to support 35% and 40% of the service loads, respectively. Gender, sitting postures, and chair and desk designs influenced load distribution patterns significantly.
Manga Bengono Dominique MartialJean Gaston TambaJoseph Zobo MfomoEvariste Fongnzossié Fedoung...
9页
查看更多>>摘要：ABSTRACT This study aims to determine the sorption isotherms of three tropical woods from Cameroon to understand the conditions for their use and drying. The equilibrium moisture contents were experimentally determined using saturated salt solutions. Some anatomical parameters were also measured to assess the influence of the structure of these woods on their sorption behaviour. Among the sorption models tested, the Guggenheim-Anderson-de Boer model is the one that best fits the experimental points. Our results also reveal a strong correlation between EMCs and the size and number of anatomical parameters. Indeed, up to 40°C, Sipo which has the lowest wood density and larger vessel sizes and rays, contains more water at equilibrium that the two other woods. When temperatures increase above 50°C, Sapelli becomes more hygroscopic due to the expansion of its lumen cells. These findings highlight the need for specific data on the sorption behaviour of Central African woods, to efficiently manage their drying and use.
查看更多>>摘要：ABSTRACT This research was conducted to detect changes in the mechanical properties of samama wood (Anthocephalus macrophyllus) after impregnation with boron, castor bean oil, and heat treatment. Samama wood has low durability so samples were impregnated with boric acid followed by impregnation with castor oil in order to achieve some fixation of the boric acid. After impregnation, heat treatments were applied for four hours at 80°C and 160°C. Results showed that the modulus of elasticity (MOE), modulus of rupture (MOR) and hardness of samama wood generally increased after the treatments. Compared with the control, the maximum differences in MOE and MOR were 19.9% and 26.7%, respectively. Castor oil treatment also increased the density and hydrophobicity of the samama wood.
NSTL
Taylor & Francis