• Composites Research
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• v.19 no.6
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• pp.38-42
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• 2006

Wood Plastic Composite(WPC) has been introduced as a new constructional material in Europe and North America. The maintenance-free durability against weather was accepted by customers and the environment-friendly merits ignited the abrupt increase of market size. Domestic major companies have kicked off the WPC business at the market of outdoor constructional materials. Due to the high contents of natural wood fiber, the production equipments should be modified to remove the moisture, to prevent thermal degradation and to promote output rates. Materials including functional fillers play a critical role in rheological properties, which affects the physical and mechanical properties of the last products. More research might be performed for synergy effects combined by various academic fields from mechanical and chemical engineering to polymer process and material science.

• Journal of Korean Society of Forest Science
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• v.107 no.3
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• pp.305-315
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• 2018

This study conducted to estimate the influences of policy which prohibits illegal logging trade. Before analyzing of the economic effects for this policy, scenario methods were selected to inflect economic circumstance by implementing it. In order to do, the policy experiments were carried out using equilibrium displacement equation model. Results show that change ratio of log price was increased 0.066%~0.071%. Since the primary import country of log is New zealand which is high CPI score rather than Republic of Korea so that imported quantity of log was decreased thinly. Because imported log price is worked as a cost in the lumber market, if the imported log price was increased, supply of lumber has to be decreased. So that, not the change ratio of domestic lumber price was increased 0.885%~4.179% but supply of domestic lumber was increased 5.367% respectively along the goods features as a heterogeneity or homogeneity on the market.

• Journal of Forest and Environmental Science
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• v.30 no.4
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• pp.362-369
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• 2014

This study investigated physical properties and combustion gas characteristics for 8 types of wood pellets (4 domestic and 4 imported products) distributed in the domestic market. Results showed that most pellet types were first-grade pellets in the wood pellet quality standards in Korea with the exception of 3 pellet types from K company (second-grade in mechanical durability), G company (off-grade in nitrogen content) and P company (second-grade in ash percentage). Mixed pellets which contained more lignin and sap content were higher in mechanical durability (%) than that of white pellets. From the combustion gas analysis results, NOx emitted from all pellets combustion was at acceptable levels for national emission standard of the Clean Air Conservation Act except for pellets from G company. In addition, CO levels from all types of wood pellets were acceptable except for pellets from D company and domestic pellets were higher CO levels than imported pellets. These results indicate the higher CO levels in domestic pellets due to the usage of forest thinning materials including logging debris which usually had the high content of bark.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.254-260
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• 2015

This paper assesses the tariff reduction on imported wood products that will have impact on the demand for domestic wood products in South Korea, by estimating the Armington substitution elasticities based on the assumption that they are imperfect substitutes. Results indicate that domestic and foreign wood products are far from perfect substitutes to each other. The substitution elasticities in plywood and fiberboard appeared to be high, implying that tariff reduction may have negative effects on those industries. On the contrary, imported and domestic particleboard showed a low substitution elasticity. The decline of fiberboard industry may lead to the decline in forestry since fiberboard is produced mainly by thinned woods supplied from domestic forests. Therefore, effective countermeasures to enhance the competitiveness of wood products industry are needed to cope with the market opening.

• Composites Research
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• v.20 no.2
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• pp.32-38
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• 2007

Natural fibers can refer to all types of fibres only produced by nature. Their lengths vary from particles to long strands. Natural fibers are categorized roughly by six types, depending on the types of sources; base, leaf, seed, grasses, fruit and wood. Of these fibers, jute, flax, sisal and ramie are the most commonly used as reinforced materials in preparing polymer composites. In development and improvement of these composites, many studies have been implemented to overcome the drawbacks such as incompatibility, moisture problems and so on. The range of industry sectors of natural fiber-reinforced polymer composites becomes more extensive gradually and many of the companies all over the world are engaged in fabrications or applications. This paper mainly discussed the recent status of the domestic/overseas market and research issues of natural fiber-reinforced polymer composites. We made an exception of wood-polymer composites market which have played a great role because they had been often dealt with.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.521-530
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• 2011

Nowadays, market demand of structural Glulam is growing and diversifying. The durability of Glulam should be significantly considered when they are intended to apply for out-door use such as timber bridge and pergola. This study was aimed to develop the manufacturing process of preservative treated structural Glulam using domestic softwood species. 10 m long structural Glulam were manufactured from domestic pitch pine logs with CuAz-3 preservative treatment. At each manufacturing process, the production yield was evaluated. Finally, bending tests were performed to verify the structural performance of manufactured Glulam. From the results, it was shown that the preservative treatment process hardly influenced on the production yield. But domestic pitch pine was proved to not be suitable for making the preservative treated Glulam due to the large difference of preservative permeability between sapwood and heartwood.

• Journal of the Korean Wood Science and Technology
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• v.39 no.5
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• pp.429-436
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• 2011

The selected physical and mechanical properties of non-certificated LVL circulated in domestic lumber market were investigated and compared to relevant standards. The tested LVL passed the moisture content and the soaking delamination rate limit as per domestic (KS) and Japanese standard (JAS). The evaluated mechanical properties were flatwise/edgewise bending strength, modulus of elasticity (MOE), horizontal shear and compressive strength. The 30 mm-thick LVL showed significantly higher bending strength than that of the 25 mm-thick LVL. The modulus of elasticity (MOE) showed same tendency in the results of bending strength. The edgewise bending strength and MOE were higher than that of flatwise bending strength and MOE. The horizontal shear strength values were also showed similar results to bending strength values. The tested results were compared each other and each products were graded according to JAS 701 grade specification. The failure mode of LVL in bending test showed the similar failure mode of solidwood that failed in a simple tension manner (splintery tension). The glue line failure was severe in 25 mm-thick specimens due to concentration of shear stress in layer discontinuity containing small voids and starved glue lines. In horizontal shear strength test, failure mode of LVL showed the typical horizontal shear failure. Compressive specimens failed with fiber crushing in company with apparent delamination that splitted along the length of the specimens. From the results, the complete bonding between lamination and consistency in thin veneer layer were considered as a critical factor in the mechanical properties of LVL. Moreover, the standard test procedure and specification for non-certificated LVL should be required to check the performance of uncertificated materials.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.258-268
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• 2013

Wood-based products market is new growth engine industry of "Green growth policy". Korean government established a law, sustainable use of wood, for expanding wood and wood-based products market in 2012. This study was conducted to seek sustainable measures for conservation and management of valuable natural resources, offer expanding quality assurance services for wood-based products, and explore measures for expanding wood-based products labeling system. Through discussed domestic and overseas trends and literatures that concern wood-based products labeling system and investigated case studies that were presently operational. For expanding quality assurance services of wood-based products, Korea Forest Service operates a wood-based products labeling system in integrated management through variety awareness and specialist assessment for each product. This process will make enhanced wood-based products labeling system expanded gradually. To evolve into $3^{rd}$ party quality assurance services on maturity age of labeling system, public communication will help improve awareness of producer and consumer. appropriate incentive program will attract voluntary participation from woodbased product industry. Producers consider environmental ethics in their business and consumer should exercise their right to know.

• Journal of the Korean Wood Science and Technology
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• v.35 no.2
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• pp.61-68
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• 2007

The applicable scope of adhesives in the current society is broad and currently, several types of PVAc resin are sold in the market for adhesives. PVAc resin is primarily used for wood works and paper adhesion. However, the PVAc resin itself has the disadvantages that its viscosity is highly temperature- dependent and the work condition and viscosity get worse at the low temperature in the winter seasons. Although phthalate-based plasticizer is used to complement these disadvantages, adhesion strength and heat-resistance are weakened by adding the phthalate-based plasticizer and in the winter period, the amount of quantity should be increased. Also in a high-density product, it worsens the work condition by causing a rise of viscosity and delays curing and in a low-density product, it worsens the storage stability by causing separate precipitation. In addition to these, the phthalate-based plasticizer as a material of causing environmental hormones is currently restricted in the advanced countries for its amount of use and also in the domestic market, it is necessary to prepare for the situation. This study has not only eliminated the disadvantages of PVAc resin emulsion without adding a phthalate-based plasticizer of causing these problems, but also synthesized the PVAc resin for timber adhesion that is excellent in woodwork, thermal-resistance, water-resistance, storage stability, and adhesion performance. As the result, it has proven an excellent performance in thermal resistance, water resistance, storage stability, and minimum film forming temperature.

• Journal of the Korean Wood Science and Technology
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• v.46 no.4
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• pp.323-337
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• 2018

Merkusii pine wood (Pinus merkusii) was extensively planted throughout Indonesia, where it is only indigenous in northern Sumatera, by the Dutch during colonial times. The demand for this wood species, especially in the domestic market, has increased notably, despite its limited durability regarding decay resistance. The purpose of this study was to investigate the occurrence of juvenile and mature wood on merkusii pine and to analyze its radial features from pith to bark based on density, shrinkage, static bending in modulus of rupture and modulus of elasticity, fiber length, microfibril angle, and durability. A segmented modeling approach was used to find the juvenile-mature transition. The graveyard test was performed to characterize the termite resistance from pith to bark of merkusii pine. The maturations were estimated to start at radial increments of 15 cm from the pith by fiber length and of 12 cm from the pith by microfibril angle. The projected figures for the proportion of juvenile wood at breast height were around 65%. The results also indicate that the pine wood was $0.52g/cm^3$ in density, 1.45 in coefficient of anisotropy, which indicates its good stability, 7597 MPa in modulus of elasticity, and 63 MPa in modulus of rupture. Natural durability against subterranean termite of the merkusii pine wood was rated to be grade 4 to 0 from pith to bark. However, after being treated by Entiblu and Enborer preservatives, its rating increased to grade 10 to 9.