한국목재공학회

DOI: JKWST Vol.48(No.4) 1-1, 2020

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한국목재공학회

DOI: JKWST Vol.48(No.4) 2-2, 2020

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Sohyun Park , Yeonjung Han , Dong Won Son

DOI: JKWST Vol.48(No.4) 417-430, 2020

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The flame retardancy, such as carbonized length and area, of four plank type wood products by the spreading concentration and impregnation time of flame retardant were measured according to standard of the Nation Fire Agency in Republic of Korea. To measure the flame retardancy, Korean pine plywood, Japanese larch plywood, Japanese cypress planks, and perforated birch plywood boards were treated with self-development flame retardant by 300 and 500 g/m2 spreading concentration and those were compared with control specimen. In general, the flame retardant performance of wood products improved as the spreading concentration of flame retardant increased. Except for Japanese larch plywood, there was no significant difference in the flame retardant performance by the spreading concentration. The flame retardant performance of perforated birch plywood board was positively correlated up to 60 minutes of impregnation time, but then gradually decreased. These results about the flame retardancy of wood products by spreading concentration and impregnation time were expected to be basic data for improving flame-retardant treated wood.

Hyejung Cho , Won-jae Yoo , Jinsoo Ahn , Sang-jin Chun , Sun-young Lee , Jaegyoung Gwon

DOI: JKWST Vol.48(No.4) 431-449, 2020

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Structural property of most hydrogels is soft, resulting in low mechanical performance that limits their usage in the biomedical applications. For overcoming the drawback, cellulose nanocrystals (CNCs) were adopted in this study. Effects of CNCs on characteristics and drug delivery performance of poly (vinyl alcohol) based hydrogels were explored. FT-IR results showed that the fabricated hydrogels had semi-IPN (semi-interpenetrating polymer network) by formation of acetal and aldehyde bridge. Water absorption and swelling ratio decreased with increasing CNCs content, and the hydrogels with CNCs showed better viscoelastic performance than the without CNCs. Also, CNCs mostly improved the ability of the hydrogel to absorb the drug and the sustainability of the drug release. These results demonstrated that incorporating CNCs into the hydrogel systems can be a good alternative to improve drug delivery performance and mechanical property of the hydrogels.

Hyoung-woo Lee , Soon-bae Kim

DOI: JKWST Vol.48(No.4) 450-457, 2020

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Single pellet press technology allows for fast, low-cost, and small-scale tests to investigate pelletizing characteristics. We estimated proper compression ratios for five Korean domestic wood species through predicted relationships between pelletizing pressure P_x and compression ratio based on experimental data obtained from a single pellet press unit. The pressures required to obtain a 6-mm-diam pellet of density 1200 kg/m³ were estimated as 111 MPa for Populus davidiana, 133 MPa for Robinia pseudoacacia, 136 MPa for Quercus mongolica, 97 MPa for Pinus densiflora, and 127 MPa for Pinus rigida. On the basis of these pressures, we estimated proper compression ratios to be within the range 7.676-8.410 for these species, and we found the compression ratios needed for hardwood species to be somewhat higher than those needed for softwood species to obtain the pellet density of 1200 kg/m³.

Sarah Augustina , Imam Wahyudi , I Wayan Darmawan , Jamaludin Malik , Efrida Basri , Yoichi Kojima

DOI: JKWST Vol.48(No.4) 458-471, 2020

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Effect of pre-treatment and compression ratio on specific gravity (SG) and dimensional stability improvement of three lesser-used wood species from natural forest area of North Kalimantan Province, Indonesia had been investigated. Hot soaking at 80 ℃ for 3 hours within 2 and 5% of boron solution was applied as pre-treatment, while compression ratio applied was 20 and 40% from the initial thickness. Densification was conducted using hot pressing machine at 30 kg/cm² of pressure and 160 ℃ of temperature for 15 minutes. Specific gravity was measured gravimetrically, while dimensional stability was evaluated through thickness swelling and water absorption as the indicator. Results show that SG of densified wood was influenced by wood species and compression ratio, but not by pre-treatment applied; while dimensional stability was influenced by wood species, compression ratio, and pre-treatment. Specific gravity and water absorption of densified wood was improved significantly. Specific gravity increased 28.86-63.03%, while water absorption decreased 12.80-15.89%. Thickness swelling of 20% densified wood was lower than that of 40% densified wood.

Hae Keum Park , Seog Goo Kang

DOI: JKWST Vol.48(No.4) 472-487, 2020

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With the emergence of abnormal climate due to the rapid industrialization, the importance of water quality management and management costs are increasing every year. In Korea, for the management of total phosphorus and total nitrogen, the major materials causing the water quality pollution, coagulants are injected in sewage treatment plants to process organic compounds. However, if the coagulant is injected in an excessive amount to PAC (Poly Aluminium Chloride), a secondary pollution problem might occur. As such, a study on the applicability of natural material-based coagulant is being conducted in Korea. Thus, this study aimed to evaluate the applicability of a mixed coagulant developed by analyzing water quality pollutants T-P, T-N as well as their turbidity, in order to derive the optimum mixing ratio between PAC and torrefied wood flour for the primary settling pond effluent. Under the condition where the content of PAC (10%) and torrefied wood flour is 1%, T-P showed the maximum removal efficiency of 92%, and T-N showed approximately 22%. This indicates that removal of T-N which includes numerous positively charged organic compounds that are equivalent to mixed coagulant is not well accomplished. Turbidity showed the removal efficiency of approximately 91%. As such, 1% of torrefied wood flour was determined to be the optimum addition. As a result of analyzing the removal efficiency for organic compounds by reducing PAC concentration to 7%, T-P showed a high maximum removal efficiency of 91%, T-N showed 32%, and turbidity showed the maximum of 90%. In addition, a coagulation process is performed by using the mixed coagulant based on 1% content of torrefied wood flour produced in this study by performing a coagulation performance comparative experiment with PAC (10%). As a result, PAC concentration was reduced to 30-50%, a similar performance with other coagulants in market was secured, PAC injection amount was reduced that an economic effect can be achieved, and it is considered to perform a stable water treatment that reduces the secondary pollution problem.

Hee-jun Park , Seok-un Jo

DOI: JKWST Vol.48(No.4) 488-502, 2020

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In this study, the moisture absorption and desorption properties presented by the Health-Friendly Housing Construction Standards of South Korea were compared using the wood of three tree species (Douglas-fir, Hinoki, Larch) and two types of wood-based materials(Plywood, WML Board^Ⓡ). The national standards for functional building materials present that the amounts of moisture absorption and desorption should be at least 65g/㎡ on average, respectively according to the test method under KS F 2611:2009. Therefore, in this study, the moisture absorption/desorption properties of materials with no treatment (Control), with punching, and with surface stain finishing and the moisture absorption/desorption property improvement effects of the treatments were compared and analyzed. According to the results of this study, it was evaluated that all five types of wood and wood-based materials tested did not satisfy the amount of moisture absorption/desorption of at least 65g/㎡, which is the performance standard for moisture absorption/desorption functional building materials, indicating that untreated wood and wood-based materials cannot be applied as functional finishing materials according to the Health-Friendly Housing Construction Standards. The surface stain finishing greatly reduced the moisture absorption and desorption rates of the materials, and the amounts of moisture absorbed and desorbed were also shown to decrease by at least two times on average. When the surfaces of the materials were punched with ∅4mm holes at intervals of 20 mm, the moisture absorption/desorption areas increased from 18% to 51%, and this increase was shown to be capable of increasing the amounts of moisture absorbed/desorbed by 29% on average at the minimum, and 81% on average at the maximum. The effects of punching were shown to be identical even in cases where the materials were stain finished. For the application of wood or wood-based materials as eco-friendly, health-friendly, and moisture absorption/desorption functional building materials hereafter, it is judged that new physical and chemical improvement studies should be conducted, and treatment methods should be developed.

Seri Maulina , Gewa Handika , Irvan , Apri Heri Iswanto

DOI: JKWST Vol.48(No.4) 503-512, 2020

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Using Na₂CO₃ versus NaCl as chemical activator, we compared the quality of activated carbon produced from oil palm fronds as raw material. These activators were selected for comparison because both are readily available and are environmentally friendly. In the manufacturing, we used Indonesian National Standard (SNI 06-3730-1995) parameters. For the quality comparison, we determined activated-carbon yield, moisture, ash, volatiles, and fixed-carbon contents; and adsorption capacity of iodine. The best characteristics, assessed by morphological surface analysis and Fourier transform infrared (FTIR) spectral analysis, were observed in the carbon activated by Na₂CO₃ at an activator concentration of 10% and carbonization temperature of 400 °C. The results were as follows: activated-carbon yield, 84%; water content, 8.80%; ash content, 2.20%; volatiles content, 14.80%; fixed-carbon content, 68.60%; and adsorption capacity of iodine, 888.51 mg/g. Identification using the FTIR spectrophotometer showed the presence of the functional groups O-H, C=O, C=C, C-C, and C-H in the Na₂CO₃-activated carbon.

Ratih Damayanti , Evi Sribudiani , Sonia Somadona , Djarwanto , Didi Tarmadi , Yusup Amin , Sulaeman Yusuf , Esti Rini Satiti , Wa Ode Muliastuty Arsyad , Rudianda Sulaeman , Syafrinal , Dwi Ajias Pramasari

DOI: JKWST Vol.48(No.4) 513-526, 2020

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The existing preservation methods are difficult to be applied to a large dimension log which is needed for making traditional wooden ship ‘Jalur’ in Riau Province. Novel techniques to provide the use of readily available species to replace traditional species alternative were investigated. These included infusion and a combination of injection and bandage-wrapping methods for preserving living trees of Balam (Macaranga conifera (Rchb.f. & Zoll.) Müll.Arg.) and Bintangor (Calophyllum soulattri Burm.f.). Water-based boron compounds were applied as wood preservatives. In total, 18 discs from the bottom, middle, and top of four trees and two controls were used. Trees undergoing treatment were also used to see how wood anatomical structure might affect the boron penetration. The overall aim was to identify the best method for use in Jalur manufacturing. The results showed that in infused Balam tree where the hose position for the preservative intake was deep (10-15 cm from the bark), no boron compound was observed in the outer sapwood. Combination of injection and bandage-wrapping method gave higher percentage of boron penetration at bottom and middle of Balam tree. However, infused Bintangor showed 100% boron penetration. The larger vessel diameter, the absence of tyloses, and the simple perforation plates in Bintangor wood were likely to have contributed to the higher penetration of boron. The combination of bandage-wrapping and infusion, or alternatively by infusing the living trees close to the bark, and at as low as position in the stem gives better protection when treatments are applied to living trees.

Youngseok Ham , Jiyoon Yang , Won-sil Choi , Byoung-jun Ahn , Mi-jin Park

DOI: JKWST Vol.48(No.4) 527-547, 2020

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Fish pathogens cause not only economic damages to fish farming but also infectious pathogens known as a zoonotic agent. Since the continued use of antibiotics to control fish pathogens entails side effects, materials of natural origin need to be developed. The purpose of this study is to discover coniferous essential oils with excellent antibacterial effects in order to develop antibiotic alternatives. We have extracted essential oils using hydro-distillation from the leaves of Abies holophylla, Pinus thunbergii, Pinus parviflora, Tsuga sieboldii, and Pinus rigitaeda, which are all Pinaceae family. And, we have evaluated antibacterial activity with the extracted essential oils against Edwardsiella tarda, Photobacterium damselae, Streptococcus parauberis, and Lactococcus garvieae, which are fish pathogens. As a result, the essential oils from A. holophylla and P. thunbergii showed the selectively strong antibacterial activity against E. tarda and P. damselae, which are gram-negative bacteria. From GC-MS analysis, it was identified that main component of A. holophylla essential oils are (-)-bornyl acetate (29.45%), D-limonene (20.47%), and camphene (11.73%), and that of P. thunbergii essential oils is α-pinene (59.81%). In addition, we found three compounds: neryl acetate, (-)-borneol, and (-)-carveol, which are oxygenated monoterpenes. These exist in a very small amount but exhibit the same efficacy as essential oil. Therefore, we expect that A. holophylla and P. thunbergii essential oils having excellent growth inhibitory effect against gram-negative fish pathogens can be used as biological products such as feed additives and fishery products.

Si Young Ha , Ji Young Jung , Jae-kyung Yang

DOI: JKWST Vol.48(No.4) 548-561, 2020

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Paecilomyces japonica is widely cultured to produce mycelium for medicinal and health food use. Illumination is an important factor in the growth and production of mycelium in submerged culture. The effects of different light-emitting diode (LED) combinations on the growth and cordycepin content as bioactive substances of mycelium were investigated. The results showed that the mycelium dry weights were lower under dark condition and red LED treatments. Dark condition, fluorescent light, and ultraviolet-A failed to increase the cordycepin content. Blue light was necessary to increase the cordycepin content, and a red-to-blue ratio of 3:7 induced the highest cordycepin content. The cordycepin contents of mycelium in submerged culture were significantly higher in a 12 h/day illumination time under red and blue (red-to-blue ratio of 3:7) LED treatments, showing an increase of up to 38% compared with those under the fluorescent-light control condition. The results demonstrated the roles of light with different wavelengths on the biosynthesis of cordycepin as bioactive substances. The low-heat release and replacement of traditional fluorescent lights with low-energy-consuming LEDs could increase the contents of bioactive substances. After optimization of the cordycepin production using response surface methodology (Box-Behnken design) to its canonical form, the optimum combination was found to be as follows: illumination time = 17.7 h/day, sugar content in the medium = 9.7 g/50 mL, and incubation time = 61.2 h. The model predicted a maximum response of 3779.2 μg/mL cordycepin yield.

Sei Chang Oh

DOI: JKWST Vol.48(No.4) 562-568, 2020

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This study investigates the relationship between ultrasonic velocity and density in the direct method, the effect of distance between transducers in the indirect method, and the difference between the direct and indirect methods with transducers placed at a distance of 200 mm in nondestructive ultrasonic testing of spruce lumber. The direct method using 54 kHz ultrasonic transducers was applied to two planes, namely, radial section (LR) and tangential section (LT) of samples. The indirect method measurements were taken using the same transducers. Two velocities were measured at the top and bottom of the LT plane and at the two sides of the LR plane; the two values for each plane were averaged. The relationship between density and ultrasound velocity in the direct method demonstrated a positive correlation between the two variables. The difference between the two planes, LT and LR, was not statistically significant. Moreover, the distance between the transducers in the indirect method affected ultrasound velocity, with the ultrasonic velocity increasing as the distance between the transducers became larger. A transducer distance of 200 mm yielded a close approximation of the direct method results with a ratio of 0.87. Finally, no statistical evidence of a difference between the two planes in the indirect method was found. If the direct method, which requires access to two surfaces, is impractical, the indirect method can be applied.

Ji-yeol Kim , Soo-chul Kim , Byung-ro Kim

DOI: JKWST Vol.48(No.4) 569-576, 2020

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This study investigated the characteristics of microfibril angle(MFA) in order to see if there was any difference in pine tree lumber quality among the three mountain areas surrounding the Taebaek Mountains in Korea - Yeongdong (Goseong-gun), Yeongseo (Hongcheon-gun) and Yeongnam (Bonghwa-gun). Pine trees of each mountain area were divided into earlywood and latewood in relation to heartwood part (1959 ∼ 1961, 3 annual rings) and sapwood part (2002 ∼ 2004, 3annual rings), and measured at tangential section. The microfibril angle showed significant differences between mountain areas. In general, Goseong Mountain was found to have 37.35°, followed by Hongcheon Mountain 32.42° and Bonghwa Mountain 25.75°, in order. The sapwood part had larger angle than heartwood part; and earlywood, than latewood. Variation within a single annual ring tended to be smaller from earlywood toward latewood.

한국목재공학회

DOI: JKWST Vol.48(No.4) 577-578, 2020

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한국목재공학회

DOI: JKWST Vol.48(No.4) 579-579, 2020

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한국목재공학회

DOI: JKWST Vol.48(No.4) 580-580, 2020

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