Basic Engineering Properties of Laminated Veneer Lumber Produced from Tropical Hardwood Species

One of the reasons for a limited structural usage of L VL in tropical countries is the lack of research and development to establish design criteria for this material. Such information is essential for the development of design values as well as new structural uses of LVL.. This study aimed to establish basic engineering properties of L VL produced from selected tropical hardwood species i.e. Yellow Meranti (Shorea spp.), Kedondong (Conarium spp), Bintangor (Calophylhlm spp ), White Meranti horea spp.), and Kerning (Dipterocarpus spp). Tests for static bending, bending shear, tensile and compression parallel to longitudinal axis were carried out using in-grade size specimens. The tests were conducted in accordance withASINZS 4357 (Structural Laminated Veneer Lumber). The effects of two important factors (I) wood species and (2) veneer thickness, on the strength properties of LVL were studied. The results show that Kerning LVL has the highest density (700 - 820 kglm3), followed by White Meranti (600-680 kg/m Bintangor (570-590 kg/m, Kedondong (545-574 kg/m3) and Yellow Meranti (510-541 kg/m3). Using thinner veneers increased the LVL panel density between 2.8% (in Kedondong) to 8.9% (in Kerning). Despite having lower board density. both White Meranti and Bintangor LVLs had significantly superior engineering properties than those made from Keruing, Kedondong and Yellow Meranti. Keruing LVL performed below the expectation in all the strength properties which was attributed to the poor bond quality observed through the gluebond shear test and scanning electron microscope analysis

Bending properties of Laminated Veneer Lumber produced from Keruing (Dipterocarpus sp.) reinforced with low density wood species

Low density wood such as Pulai (Alstonia sp.), Sesendok (Endospermum sp.) and Kekabu Hutan (Bombax sp.) have never been regarded as structural material due to their inferior strengths. Converting these timbers into Laminated Veneer Lumber (LVL) and reinforcing them with stronger timber could turn them into much sought after materials. This study discusses the effects of incorporating Keruing veneers into LVL panels made from low density wood. Laminated Veneer Lumber comprised 11-ply and 15-ply veneers fabricated by arranging Keruing veneers located at the surface and the low density woods were arranged as core. Phenol Formaldehyde (PF) resin was used as the binder. The LVLs were subjected to cyclic boil-dry test according to voluntary product Standard PS1-95: Construction and Industrial Plywood. The bending properties and percent delamination were determined according to the Japanese Agricultural Standard (JAS) for Structural LVL: 1993 before and after the cyclic boil dry treatment. Result showed through incorporating low density wood with Keruing veneers, both 11-ply and 15-ply LVL panels achieved the minimum requirements for various grades stipulated in the JAS for Structural LVL Standard: 1993. At the same panel thickness, 15-ply LVL shows a better performance compares to those of 11-ply LVL. Presence of Keruing veneers as surface layers significantly increased the strength of the LVL panels. All panels passed the delamination test stipulated on the JAS for Structural LVL: 1993. Conclusively, combining Keruing and the low density wood veneers in LVL fabrication gave greater strength and more stable material

Solid hardwood flooring resistance to termites (Coptotermes curvignathus) under laboratory condition

Hardwood flooring is generally manufactured using solid timbers because they can withstand harsh weather conditions and are more resistant to pest attack. In Malaysia, a major pest to timber structures is the subterranean termites. To prevent wood degradation by termites, chemical preservatives have been applied to wood. However, this practice is not environmentally friendly and may be hazardous to humans, thus creating the demand for naturally durable wood. In this study, the durability of six local and three foreign tropical hardwoods against Coptotermes curvignathus were tested in the laboratory. Untreated solid hardwoods were each cut into replicate test wafers of 25 mm square by 6 mm in the radial direction and were exposed to 400 termites (360 workers and 40 soldiers) in culture bottles following AWPA El-97 protocols. After four weeks, visual rating, mass loss of each sample and termite mortality were determined. All the test samples subjected to C. curvignathus had 100% mortality rate, sample weight losses of 3.30-8.52%, and a minimum visual rating of 9.0 at the end of a 4-week test. There was a weak correlation between specific gravity and mean mass loss of the samples. Our results suggest that local hardwood species 'bids' (Madhuca utilis) and 'kekatong' (Cynometra malaccensis), and a foreign species 'pyinkado' (Xylia dolabriformis) are highly resistant to C. curvignathus attack and could be used as flooring materials without chemical treatment

Trends in Seaweed Research

This is a letter on the evolution of trends in seaweed research with respect to the development of technology and generation of knowledge, as well as difficulties and future perspectives in seaweed research

SCS+C Topographic Correction to Enhance SVM Classification Accuracy

The topographic impact may change the radiance values captured by the spacecraft sensors, resulting in distinct reflectance value for similar land cover classes and mischaracterization. The problem can be more clearly seen in rugged terrain landscapes than in flat terrains, such as the mountainous areas. In order to minimize topographic impacts, we suggested the implementation of Modified Sun-Canopy-Sensor Correction (SCS+C) technique to generate land cover maps in Gua Musang district which is located in a rugged mountainous terrain area in Kelantan state, Malaysia using an atmospherically corrected Landsat 8 imagery captured on 22 April 2014 by Support Vector Machine (SVM) algorithm. The results showed that the SCS+C method reduces the topographic effect particularly in such a steep and forested terrain with classification accuracy improvement about 4 % which was statistically significantly with the McNemar test value Z and P measured 6.42 and 0.0001 on the corrected image classification 90.1 % accuracy compared to the uncorrected image 86.2 % for the test area. Thus, the topographic correction is suggested to be the main step of the data pre-processing stage in mountainous terrain before SVM image classification

Anatomical structures and fiber morphology of new kenaf varieties

Kenaf plant is claimed as one of the fast-growing herbaceous plants with the high potential as a fiber material or lignocellulosic material. Nine kenaf varieties i.e., Q-Ping, KK60, V12, V19, V36, V132 and NS V133 and TK were introduced recently by Taman Pertanian Universiti, Universiti Putra Malaysia as one of the potential plant to replace tobacco plantation. Since, these nine kenaf varieties are new to Malaysia, therefore, there is a need to study their anatomical structures and fiber morphology as well as microscopic appearances to understand their different and similarity. Cell morphology and anatomical appearances were observed and evaluated under the image analysis system (Leitz DMRB). From the results, V19 and V12 had the wider ray among the nine varieties, whereas other varieties in their microscopic appearance were almost similar to those observed in many diffuse-porous hardwoods. The longest fiber length was observed in variety TK (2.96 mm) followed by V36. Q-ping showed the widest fiber diameter and lumen diameter amongst the nine varieties, with value of 28.64 μm in bast fiber and 28.06 μm in core diameter. However, Q-ping had the thinnest core cell wall with the thickness of 3.34 μm. In term of fiber length, all the kenaf varieties bast fiber has longer fiber than core fiber. The kenaf core of nine varieties has wider fiber diameter and fiber lumen diameter than the bast fiber. Conclusively, although kenaf exhibit similarity in some fiber morphology and anatomical structures, however, there still some distinction that can be used to differentiate these kenaf variety

Production of low formaldehyde emission particleboard by using new formulated formaldehyde based resin

In order to preserve the global market competitiveness, the particleboard industry was affronted with challenges to reduce formaldehyde emission while maintaining the quality strength properties of particleboard. To counter the issue, particleboards with five different surface-to-core ratio were fabricated by applying newly formulated UF and MUF resins which were 30% surface: 70% core (3:7); 40% surface: 60% core (4:6); 50% surface: 50% core (5:5); 60% surface: 40% core (6:4) and 70% surface: 30% core (7:3) based on dry particle weight respectively. Formaldehyde emission and strength properties of the fabricated particleboard were investigated based on Japanese Industrial Standard, which are JIS A 1460 and JIS A 5908, respectively. All the MUF-bonded particleboard complied with the type 18 standard, whereas all the UF-bonded particleboard produced complied with type 13 except thickness swelling of the UF-bonded particleboard. The surface-to-core ratio applied in three layered particleboard for both resins exerted considerable influence on the strength properties and formaldehyde emission of particleboards produced from both resins. MUF-bonded particleboard with 40% surface and 60% core recorded the lowest formaldehyde emission (0.09 mg L-1) and highest strength properties. For UF-bonded particleboard, the ratio of 60% surface and 40% core showed the lowest formaldehyde emission (0.28 mg L-1) with better strength properties. This study highlighted the potential of MUF resin to replace UF resin due to its ability to produce F**** particleboard with better strength properties and lower formaldehyde emission according to JIS A 5908

Enhanced properties of single-layer particleboard made from oil palm empty fruit bunch fibre with additional water-soluble additives

The efficacy of additional water-soluble additives was studied relative to the physical and mechanical properties of particleboards produced from oil palm empty fruit bunch (OPEFB). Polyethylene glycol, acrylamide, and acrylic resin were selected as water-soluble additives for use in the OPEFB particleboard production process. The effects of the three additives at two different concentrations (2% and 4% of dry OPEFB mass) on the particleboard properties were evaluated. Addition of water-soluble additives increased the performance of the OPEFB particleboard. The additive concentration has a significant effect on the properties of the particleboard. With the increase of additive concentration, the internal bonding and modulus of rupture value increased while the thickness swelling and water absorption decreased. Particleboards with an additional 4% of acrylamide or polyethylene glycol achieved the highest modulus of rupture (22 MPa), highest internal bonding strength (1 N/mm2), and lowest thickness swelling (9%). All the particleboards produced with 4% of water-soluble additive achieved the standard requirements of JIS A 5908:2003 for physical and mechanical properties

Valorization of waste oil palm (Elaeis guineensis Jacq.) biomass through furfurylation

Malaysia is the biggest producer of palm oil in the world. The production generates large amounts of waste trunks which should be considered a valuable bio-feedstock rather than waste. An approach for valorization of waste oil palm biomass – especially that of low density hardly applicable in industry – through furfurylation was investigated. Furfuryl alcohol treatment resulted in great improvement in the properties of the material: 200% density gain, water absorption and thickness swelling reduced by 50% and 74%, respectively, hardness increased by 400%, as well as 3.5-fold and 7.4-fold increase, respectively, in bending strength and modulus of elasticity was observed. Alternations in physical and mechanical properties of oil palm trunk combined with aesthetic changes due to material darkening may be considered an effective approach for conversion of waste biomass to novel materials of enhanced technical value

Physical-mechanical characteristics of cement-bonded kenaf bast fibres composite boards with different densities

This study was carried out to explore the potential of kenaf bast fibres (KBFs) for production of cement-bonded kenaf composite boards (CBKCBs). More than 70% of the KBFs were of size >3.35 mm and length of 31±0.4 mm, therefore, they were used for CBKCBs production. The CBKCBs with the dimensions of 450 × 450 × 12 mm were produced using cement (C): KBF with proportion of (2:1) and different board densities (BD) namely 1100, 1300 and 1500 kg/m3The CBKCBs were first cured in a tank saturated with moisture for 7days, and then kept at room temperature for 21 days. Mechanical and physical properties of the CBKCBs were characterized with regards to their modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), water absorption (WA), and thickness swelling (TS). Results of the tested CBKCBs revealed that the MOR increased while the MOE decreased due to uniform distribution of KBFs. It was found that loading of KBFs has a negative influence on the internal bond (IB) of the CBKCBs; the IB was reduced as KBFs tend to balling and making unmixed aggregates with the cement. These results showed that the CBKCB is a promising construction material that could potentially be used in different structural applications due to their good mechanical characteristics