Print ISSN: 1017-0715
Online ISSN: 2233-7180
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Vol.46 No.4 July 2018
46(4) 1-1, 2018
DOI: JANT Vol.46(No.4) 1-1, 2018
Aims and Scope
46(4) 1-2, 2018
DOI: JANT Vol.46(No.4) 1-2, 2018
Determination of Moisture Index in Korea
Jong Bum Ra
46(4) 301-308, 2018
DOI:10.5658/WOOD.2018.46.4.301 JANT Vol.46(No.4) 301-308, 2018
This study aimed to obtain basic climate information for effective moisture control in wood in Korea. Two independent climate indexes, namely drying index (DI) and wetting index (WI), were determined using hourly weather data for 82 locations recorded from 2009 to 2017. These data were collected from the Korea Meteorological Administration (KMA). Hourly data had not been measured prior to 2009. DI and WI revealed that all regions were cold and wet except Baengnyeongdo, which was classified as a cold and dry region. DI and WI were normalized assuming that wetting and drying were equally important phenomena. Then, the normalized indexes were combined into moisture index (MI) to rank the moisture loading of the regions. The MIs showed that Seogwipo had the greatest moisture loading in Korea, followed by Seongsan, Namhae, and Geoje. The MIs suggested that Korea exhibited severe moisture loading. Further studies are required to investigate the relation between MI and moisture content on wood surfaces from a wood maintenance point of view.
Study on the Size Reduction Characteristics of Miscanthus sacchariflorus via Image Processing
Hyoung-woo Lee , Jae-won Lee , Sung-ho Gong , Yeon-sang Song
46(4) 309-314, 2018
DOI:10.5658/WOOD.2018.46.4.309 JANT Vol.46(No.4) 309-314, 2018
Size reduction is an important pre-processing operation for utilizing biomass as a sustainable resource in industrial-scale energy production and as a raw material for other industries. This work investigates the size reduction characteristics of air-dried Miscanthus sacchariflorus Goedae-Uksae 1 (Amur silver grass) via image processing and identifies the morphological characteristics of comminuted and screened M. sacchariflorus. At chopping lengths of 18, 40, 80, and 160 mm, 81%, 77%, 78%, and 76% of the particles, respectively, passed through a 4-mm sieve. Even a knife mill with a very small screen aperture (>1 mm) admitted over 10% of the particles. The average circularity and aspect ratio of the particles were < 0.30 and >10, respectively. These results confirm that in all preparation modes, most M. sacchariflorus particles were needle-like in shape, irrespective of the type of preparation.
Morphological Characteristics of Bambusa vulgaris and the Distribution and Shape of Vascular Bundles therein
Atmawi Darwis , Apri Heri Iswanto
46(4) 315-322, 2018
DOI:10.5658/WOOD.2018.46.4.315 JANT Vol.46(No.4) 315-322, 2018
Bamboo culm comprises internodes and nodes and is tapered from the bottom to the top. Anatomically, bamboo culm comprises vascular bundles and parenchymal base tissue. The gross anatomical structure of a transverse section of any culm internode is determined by the shape, size, arrangement, and number of vascular bundles. The purpose of this research was to examine the morphology of culm and the distribution and shape of vascular bundles in Ampel bamboo (Bambusa vulgaris). Bamboo culms were harvested from the base. Test samples were obtained from a central 2-cm long segment of each internode across the entire length of the culm. Results showed an uneven spread of vascular bundles in the internode cross-section. Transitioning from the outer to the inner layer of the internode, the number of vascular bundles per unit area decreased and their shape was variable. The size of vascular bundles in the middle layer of the internode was greater than that of those in the outer and inner layers. The shape of vascular bundles was circular in the outer layer, which gradually transformed into vertical oval toward the middle layer and horizontal oval toward the inner layer. Vascular bundles were of type III and IV in the bottom of the culm and type III in the middle to the top of the culm.
Radial Variation in Selected Wood Properties of Indonesian Merkusii Pine
Wayan Darmawan , Dodi Nandika , Britty Datin Hasna Afaf , Istie Rahayu , Dumasari Lumongga
46(4) 323-337, 2018
DOI:10.5658/WOOD.2018.46.4.323 JANT Vol.46(No.4) 323-337, 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 0.52 g/㎤ 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.
Measurement of Sound Transmission Loss in a Sound Barrier Filled with the Rice-Straw Particles by the Transfer Function and Laboratory Measurement Methods
Chun-won Kang , Eun-suk Jang , Sang-sik Jang , Ho-yang Kang
46(4) 338-345, 2018
DOI:10.5658/WOOD.2018.46.4.338 JANT Vol.46(No.4) 338-345, 2018
The sound insulation capacity of a barrier is indicated by its transmission loss. In this study, the sound transmission loss of a sound barrier filled with rice-straw particles was measured by the transfer function method and a laboratory measurement method. The results of the two measurements were compared. The transmission losses measured by the two methods were similar above a frequency of 500 Hz. The loss increased greatly upon the introduction of a plywood to the sound barrier. The results of this study are expected to be used to design sound barriers for roads.
Radical Scavenging Activity of Kemenyan Resin Produced by an Indonesian Native Plant, Styrax sumatrana
Asep Hidayat , Apri Heri Iswanto , Arida Susilowati , Henti Hendalastuti Rachmat
46(4) 346-354, 2018
DOI:10.5658/WOOD.2018.46.4.346 JANT Vol.46(No.4) 346-354, 2018
Kemenyan resin from Styrax sumatrana is a unique non-timber forest product (NTFP) native from Sumatera Island, Indonesia. It possesses a wide range of applications in the pharmaceutical, perfume, and cosmetics industries. In this paper, six kemenyan resin samples were investigated to evaluate their free radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) reagent. The kemenyan resin samples, which originated from North Tapanuli, Pakpak Bharat, and Humbang Hasundutan, showed high antioxidant activity with IC50 < 16 mg/L. The antioxidant activity of common kemenyan resin constituents, i.e., cinnamic acid, ethyl cinnamate, gallic acid, and vanillin was also investigated as positive control, although they exhibited lower antioxidant activity (IC50 < 1000 mg/L), except for gallic acid (IC50 = 5,23 mg/L). The total phenolic and flavonoid contents (TPC and TFC) for all samples were 44-66 mg gallic acid equivalents (GAE)/g sample and 143-160 mg quarcetin equivalents (QE)/g sample. The results revealed that kemenyan resin has high potency as an antioxidant and could be used as a natural antioxidant resource.
Effect of Different Pressing Processes and Density on Dimensional Stability and Mechanical Properties of Bamboo Fiber-based Composites
Ya-hui Zhang , Yu-xiang Huang , Hong-xia Ma , Wen-ji Yu , Yue Qi
46(4) 355-361, 2018
DOI:10.5658/WOOD.2018.46.4.355 JANT Vol.46(No.4) 355-361, 2018
In this study, the dimensional stability and mechanical properties of bamboo fiber-based composites (BFBCs) were studied at two pressing manufacturing processes, i.e., hot- and cold- pressing, and were compared with three density parameters (1.0, 1.1, and 1.2 kg/㎥). Width swelling ratio (WSR), thickness swelling ratio (TSR), and water absorption ratio (WAR) were calculated for water immersions of 4 and 28 h. WSR, TSR, and WAR for specimens immersed for 28 h were higher than those for 4 h treatment, which shows that the immersion time has a significant influence on the dimensional stabilities of BFBCs. Moreover, the positive linear relations between density and dimensional were observed at both the pressing ways, indicating that the WSR, TSR, and WAR decreased with an increase in the density of BFBCs. The compressive strength, shear strength, modulus of rupture (MOR), and modulus of elasticity (MOE) were determined. The compressive strength, MOR, and MOE of hot-pressed specimens were significantly higher than those for the cold-pressed specimens, which are also directly proportional to density. Moreover, the samples with the highest density of 1.2 kg/㎥ performed high values on mechanical properties in both the manufacturing methods.
Comparison of Transfer Function Method and Reverberation Room Method in Measuring the Sound Absorption Coefficient of Rice Straw Particle Mat
46(4) 362-367, 2018
DOI:10.5658/WOOD.2018.46.4.362 JANT Vol.46(No.4) 362-367, 2018
This study estimates the sound absorption capability of rice straw particle mats by two methods: the transfer function method and the reverberation room method. In the reverberation method, the central frequency was set to the one-third octave band in the 100-5000 Hz range; in the transfer function method, the frequency range was 500-6400 Hz. Both methods yielded similar noise reduction coefficients of the rice straw mats. The noise reduction coefficient was approximately 0.8, indicating a high sound-absorption property of the mats. Therefore, rice straw matting is a suitable candidate material for sound-barrier walls against highway noise.
Journal of the Korean Wood Science and Technology
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