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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Wood Science and Technology
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Journal DOI :
The Korean Society of Wood Science Technology
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Volume & Issues
Volume 43, Issue 6 - Nov 2015
Volume 43, Issue 5 - Sep 2015
Volume 43, Issue 4 - Jul 2015
Volume 43, Issue 3 - May 2015
Volume 43, Issue 2 - Mar 2015
Volume 43, Issue 1 - Jan 2015
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Chemometrics Approach For Species Identification of Pinus densiflora Sieb. et Zucc. and Pinus densiflora for. erecta Uyeki - Species Classification Using Near-Infrared Spectroscopy in combination with Multivariate Analysis -
Hwang, Sung-Wook ; Lee, Won-Hee ; Horikawa, Yoshiki ; Sugiyama, Junji ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 701~713
DOI : 10.5658/WOOD.2015.43.6.701
A model was designed to identify wood species between Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc. using the near-infrared (NIR) spectroscopy in combination with principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). In the PCA using all of the spectra, Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc. could not be classified. In the PCA using the spectrum that has been measured in sapwood, however, Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc. could be identified. In particular, it was clearly classified by sapwood in radial section. And more, these two species could be perfectly identified using PLS-DA prediction model. The best performance in species identification was obtained when the second derivative spectra was used; the prediction accuracy was 100%. For prediction model, the
value was 0.86 and the RMSEP was 0.38 in second derivative spectra. It was verified that the model designed by NIR spectroscopy with PLS-DA is suitable for species identification between Pinus densiflora for. erecta Uyeki and Pinus densiflora Sieb. et Zucc.
Physical and Mechanical Properties of Castanopsis cuspidata var. sieboldii according to Stand Characteristics in the Southern Region of Korea
Won, Kyung-Rok ; Hong, Nam-Euy ; Jung, Su-Young ; Yoo, Byung-Oh ; Byeon, Hee-Seop ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 714~720
DOI : 10.5658/WOOD.2015.43.6.714
Since physical and mechanical properties of wood are affected by environmental factors such as soil and climate change, this study investigated relationships between wood quality factors and stand characteristics of Castanopsis cuspidata var. sieboldii forest in the southern region of Korea, including Jeollanam-do Province and Je-ju island. The obtained results found very close relationships between physical and mechanical properties of wood and stand characteristics. The air-dried density and strength performance of woods showed a negative correlation with the diameter at breast height (DBH) while they were positively related to altitude and drainage of the forest site. And wood properties showed variations depending on the region. These results brought a conclusion that wood of Castanopsis cuspidata var. sieboldii in the southern region could be useful forest resources for timber production.
Wood Properties of Quercus acuta due to Thinning Intensity
Hong, Nam-Euy ; Won, Kyung-Rok ; Jung, Su-Young ; Lee, Kwang-Soo ; Byeon, Hee-Seop ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 721~729
DOI : 10.5658/WOOD.2015.43.6.721
Wood properties depend on not only environmental factors such as soil, climate change, or forest stand characteristics, but also silviculture practices such as thinning, regeneration, or selection. This study report influences of the extent of thinning intensity from no thinning, moderate and heavy thinning to the wood property of Quercus acuta forest stands in Wan-do arboretum, Jeollanam-do Province. The results showed that there were close relationships between thinning intensity and anatomical, physical or mechanical properties of Quercus acuta wood. Especially, there are close relationships between thinning intensity and ring width or mechanical properties of wood. As a result, this study showed high correlations between Quercus acuta wood properties and thinning intensity of Quercus acuta forest stand. These findings are expected to be very useful as fundamental data for the implementation of silviculture practices of this specie to produce timber.
Effect of The Addition of Various Cellulose Nanofibers on The Properties of Sheet of Paper Mulberry Bast Fiber
Han, Song-Yi ; Park, Chan-Woo ; Kim, Bo-Yeon ; Lee, Seung-Hwan ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 730~739
DOI : 10.5658/WOOD.2015.43.6.730
Various cellulose nanofibers (CNF) with different morphology and chemical properties were prepared for the reinforcement of sheet of paper mulberry bast fiber. Lignocellulose nanofiber (LCNF), Holocellulose nanofiber (HCNF), alkali-treated HCNF (AT-HCNF), TEMPO-oxidated nanofiber (TEMPO-NF) and cellulose nanocrystal (CNF) were prepared and their addition effect on the properties of sheet of paper mulberry bast fiber were investigated. Air permeability, surface smoothness, and tensile properties were improved by increasing CNF addition. Its improvement may be due to the CNF deposited between and on paper mulberry bast fibers, which was confirmed by SEM observation.
Mechanical and Thermal Properties of Hydroxypropyl Cellulose/TEMPO-oxidized Cellulose Nanofibril Composite Films
Jo, Yu-Jeong ; Cho, Hye-Jung ; Chun, Sang-Jin ; Lee, Sun-Young ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 740~745
DOI : 10.5658/WOOD.2015.43.6.740
Hydroxypropyl cellulose (HPC) composite films filled with TEMPO-oxidized cellulose nanofibrils (TOCN) were prepared in this study. In order to investigate mechanical and thermal properties of HPC/TOCN composite films, tensile strength and thermogravimetric analysis (TGA) wer performed. As the loading level of TOCN increased, the tensile strength and modulus increased significantly. However, thermal stability of HPC/TOCN composite films was not related to the loading levels of the TOCN.
Review on The Measurement of Wood Shrinkage
Lee, So Sun ; So, Won-Tek ; Jeong, Gi Young ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 746~756
DOI : 10.5658/WOOD.2015.43.6.746
The goal of this study was to review the wood shrinkage published in Journal of The Korean Wood Science and Technology from 1976 to 2015. Previous studies reported that shrinkage from Larix kaempferi in the tangential, radial, longitudinal directions ranged from 4.21%-9.79%, 2.09%-4.67%, 0.17%-0.33%, respectively. When different drying methods including closed cylinder drying, oven drying, and room temperature drying were used, volumetric shrinkage of Dipterocarpus grandiflorus was different, ranging from 31.6% to 21.0%. With an increment of the drying temperature of
, the shrinkage of Larix kaempferi did not show a consistent trend. When sample size of Pinus densiflora was increased from
, the tangential, radial and volumetric shrinkage decreased 2.61%, 1.32%, 0.80%, respectively. When a caliper having a sensitivity of 0.01 mm was used to measure
specimen from Cryptomeria japonica, the measurement error occurred 1.97% in the radial direction and 35.7% in the longitudinal direction. From the previous studies, wood shrinkage could be influenced by sample size, drying method and measurement technique.
Effect of Sawdust Moisture Content and Particle Size on The Fuel Characteristics of Wood Pellet Fabricated with Quercus mongolica, Pinus densiflora and Larix kaempferi Sawdust
Kim, Seong-ho ; Yang, In ; Han, Gyu-Seong ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 757~767
DOI : 10.5658/WOOD.2015.43.6.757
This study was conducted to investigate the effects of moisture content and particle size of sawdust on the fuel characteristics of wood pellets produced with Mongolian oak (Quercus mongolica, QUM), red pine (Pinus densiflora, PID) and larch (Larix kaempferi, LAK) sawdust using a flat-die pelletizer. Prior to produce wood pellets, the sawdust was controlled to the moisture content of 8, 11, 12% and was screened to the particle size of 2 and 4 mesh. In the analysis of its chemical composition, QUM had a high ash content, and PID and LAK contained large amount of lignin. In case of the fuel characteristics, PID pellets had the lowest moisture content of pellets (P-MC), and LAR pellets was found to have the highest bilk density (BD) and durability (DU). With the increase of moisture content of sawdust (S-MC), P-MC and DU of QUM, PID and LAK pellets increased, but BD of QUM and LAK pellets decreased. When size of sawdust used for the production of wood pellets decreased, P-MC and BD of LAK pellets and BD of QUM pellets increased. Decrease of particle size contributed to the increase of DU of QUM, PID and LAK pellets. In addition, BD and DU of QUM pellets produced with 12% S-MC sawdust increased as its particle size reduced. For LAK pellets, DU was not influence by particle size in the S-MCs of 10% and 12%, but increased with the decrease of particle size in the S-MC of 8%. Based on the results and economical aspects, 10% MC and 2 mesh paricle size for QUM sawdust and 12% MC and 2 mesh particle size for PID sawdust might be optimal conditions for pellets production, and fuel characteristics of wood pellets produced by the conditions greatly exceeded the minimum requirements for the
-grade wood pellets of the standard designated by Korea Forest Research Institute.
Combustion Properties of Major Wood Species Planted in Indonesia
Park, Se-Hwi ; Jang, Jae-Hyuk ; Hidayat, Wahyu ; Qi, Yue ; Febrianto, Fauzi ; Kim, Nam-Hun ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 768~776
DOI : 10.5658/WOOD.2015.43.6.768
This study was performed to understand combustion properties four major Indonesian wood species such as Albizia, Gmelina, Mangium and Mindi were investigated by cone-calorimeter for better utilization of theses wood species. Heat release rate (HRR), total heat release (TSR), specific mass loss rate (SMLR), effective heat of combustion (EHC), time to ignition (TTI), flame time (FT), specific extinction area (SEA), smoke production rate (SPR) and CO compound production rate were measured. HRR, THR and FT were proportional to the density of woods. Albizia showed the highest HRR, while Mindi had the lowest HRR. For SPR, Albizia showed the highest value due to its higher SEA. On the other hand, Mindi had the lowest SPR due to a lower SEA value. The highest smoke emission was for Albizia at the beginning of combustion. After 300 seconds, smoke emission of Gmleina and Mangium was increased greatly. Mangium and Mindi showed the highest total carbon dioxide emission. Expecially, Gmelina released the highest carbon monoxide during the combustion period and presented three times higher
ratio than those of other species due to incomplete combustion.
Resonance Frequency Analysis of A Baseball Bat by Impact Angle
Park, Sun-Hyang ; Chung, Woo-Yang ; Jung, Hwan-Hee ; Lee, Sang-Joon ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 777~783
DOI : 10.5658/WOOD.2015.43.6.777
Wood is an anisotropic material that shows the changes in hardness, quality and dimensions depending on the types of cells on three cross sections, size, array and so on. It can also be used in different ways according to its use, which requires a meticulous research, in order to maximize the utilization by understanding the nature and use; and by clarifying the theory and technologies. The research on relationship among wood's physical properties, density, and elasticity of modulus have been studied in Korea and abroad, but those studies were based on correlation gained through standardized specimen. Rather, the study on complete product is rare. Moreover, the previous reports are mostly concentrating on vibration mode and batting, though the wood's physical properties as a material have not been in the main focus. Therefore, this study will carried out for analyzing MOE through figuring material property out and comparing frequency adapting to the Canadian HardMaple bat. For comparison of material properties, we studied the annual ring and density of the bat; calculated the MOE with resonance frequency and formula (ASTM C1259); and verified the repulsive force of this material. As a result, the relevance of the resonance frequency and annual ring is weak, and in comparison in the grain direction in wood, the MOE value is higher when the grain direction in wood is excited horizontally than when is excited vertically, because the material is repulsive when grain direction is horizontal.
Effects of Drying Temperature and Acetylation on The Retention of Polyethylene Glycol in Red Pine Wood Disks
Lee, Won-Hee ; Hong, Seung-Hyun ; Kang, Ho-Yang ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 784~791
DOI : 10.5658/WOOD.2015.43.6.784
Polyethylene glycol (PEG) impregnation prevents a red pine disk from cross-sectional checking during drying. Percentage of PEG Retention (PPR) was measured by the experimental methods of aceton extraction and moisture conditioning in a saturated salt solution and the effect of acetylation on PEG impregnated wood was investigated. PPRs of the kiln-dried specimens were much higher than those of the air-dried by at least four times and within the kiln-dried specimens those of the sapwood were higher that those of the heartwood by two times. These results were confirmed by the moisture conditioning experiment. Acetylation increased the weights of the kiln-dried specimens much less than those of the air-dried. It was revealed that acetic anhydride solution eluted PEG-1000 in the specimens. It is concluded that kiln-drying is more effective than air-drying for the increase of PPR and that acetylation eliminates the difference between the kiln- and air-dried specimens.
Vacuum Pressure Treatment of Water-Soluble Melamine Resin Impregnation for Improvement of Mechanical Property, Abrasion Resistance and Incombustibility on Softwood
Oh, Seung-Won ; Park, Hee Jun ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 792~797
DOI : 10.5658/WOOD.2015.43.6.792
In this study, three softwood species were treated with water-soluble melamine resin by different concentration and treatment time under vacuum pressure for improving mechanical property, abrasion resistance, and incombustibility. After the treatment, a compreg was manufactured and then evaluated on physical properties. Additionally, incombustibility of compreg was determined by comparing with a wood that was treated by spraying a water-soluble fire retardant on surface. As concentration of resin increased, bending strength and Brinell hardness increased as well as abrasion resistance, but there was no correlation on treatment and mechanical properties by treatment time. The wood impregnated by water-soluble melamine resin under vacuum pressure showed better incombustibility than that of a water-soluble fire retardant sprayed wood. Therefore, this treatment could be used for improving incombustibility of wood.
Predicting Influence of Changes in Indoor Air Temperature and Humidity of Wooden Cultural Heritages by Door Opening on Their Conservation Environment
Kim, Min-Ji ; Shin, Hyun-Kyeong ; Choi, Yong-Seok ; Kim, Gwang-Chul ; Kim, Gyu-Hyeok ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 798~803
DOI : 10.5658/WOOD.2015.43.6.798
This study was conducted to predict the effect of door opening in wooden cultural heritages (WCHs) on their conservation environment. For this prediction, measured relative humidity (RH) and surface wood moisture content (MC) of inner part of wood columns in open wooden building and neighboring closed wooden building were compared with minimum RH, including the duration of minimum RH, and MC required for spore germination and resultant growth of wood-degrading fungi reported in some literatures. Moisture conditions, namely RH of inside wooden building and MC of wood was unsuitable for decay and sap-stain fungi all the year round; however, moisture conditions during summer season was suitable for spore germination and resultant growth of surface mold fungi, regardless of door opening. When compared, the duration of minimum (75%) or higher RH and the number of wood columns with MC level greater than the minimum MC (15%) during summer season, the surface mold related to the conservation environment of inside wooden building was somewhat better in open building than in closed building. Rather, doors should be opened in closed building for reducing indoor RH as a necessary measure during summer season when outdoor RH is high.
Effectiveness of Three Commercial Wood Preservatives against Termite in Korea
Lee, Hansol ; Hwang, Won-Joung ; Lee, Hyun-Mi ; Son, Dong-Won ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 804~809
DOI : 10.5658/WOOD.2015.43.6.804
Since Korea is home to Reticulitermes speratus, a kind of subterranean termites that prefer dark and humid conditions, there have been increasing damages to wooden structures by termites. One noticeable attribute of Korean subterranean termites is that they prefer than Pinus densiflora, the major construction material for Korean traditional houses. And because wide varieties of termites are distributed all over the world, it is not so easy to choose appropriate control methods depending on specific areas. This necessitates careful applications of the following control methods depending on the kinds of termites: fumigation treatment, soil termiticide, preservatives and insect treatment, termite colony elimination system, chemical treatment, and other physical and biological treatment methods. The purpose of this study is to investigate the control effects of environmentally-friendly Alkaline copper quaternary (ACQ), Copper Azole (CuAZ) and Micronized copper quarter (MCQ) on the termites contributing to the damage of wooden structures. It was found in this study that wood with preservative treatment produced a significantly higher termicidal efficacy than untreated wood.
Evaluation of Pretreatment Moisture Content and Fixation Characteristics of Treated Wood for Pressure Treatment of Yellow Poplar Skin Timber with ACQ, CUAZ and CuHDO
Kim, Min-Ji ; Choi, Yong-Seok ; Kim, Gyu-Hyeok ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 810~817
DOI : 10.5658/WOOD.2015.43.6.810
This study was conducted to evaluate the pressure treatment characteristics of yellow poplar skin timber with ACQ-2, CUAZ-3, and CuHDO-1. The effect of moisture content (MC) on treatability was investigated, and fixation characteristics of copper-based preservatives were also evaluated. Sapwood of yellow poplar, which was dried below 50 percent MC, was fully penetrated with preservatives, and minimum requirement of preservative retention for the hazard class H3 was achieved. Through measuring retention gradient in yellow poplar sapwood, it was confirmed that minimum requirement of preservative retention for the hazard class H3 was achieved in the assay zone from the surface to 15 mm-depth when the specimens were dried below 30 percent MC. Yellow poplar heartwood did not meet the minimum requirement of penetration and retention for the hazard class H3 over the range of pretreatment MCs tested. The fixation rate of copper was much faster under drying condition compared with nondrying condition; more than 90% of copper were fixed in 3 weeks at
under drying conditions.
Applicability Study on Reticulitermes speratus kyushuensis (Isoptera: Rhinotermitidae) Colony Eliminator to Preserve Wooden Cultural Heritage
Chung, Yong Jae ; Kim, Si Hyun ; Kim, Youn Ju ; Yu, Jae Seung ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 818~825
DOI : 10.5658/WOOD.2015.43.6.818
This study is conducted to develop new termite colony elimination system that can control termite colony much faster, and to eco-environmentally prevent termite damage occurred in wooden cultural heritage. As a result of laboratory test, we developed a component system, of which fipronil 0.001% (w/w) treated bait was used as a suitable termite colony eliminator. This system can be monitored without taking off underground, and it makes regular monitoring much more efficient. The result of field test showed that 36 termite baiting devices among 367 installed devices were damaged by foraging termites. After baiting, all of termite colonies attracted to devices were eliminated or their activity clearly decreased.
Antioxidant Activity of The Residue Generated During Pervaporation of Bioethanol Produced from Lignocellulosic Biomass
Shin, Gyeong-Jin ; Jeong, So-Yeon ; Lee, Hong-Joo ; Lee, Jae-Won ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 826~837
DOI : 10.5658/WOOD.2015.43.6.826
In this study, we produced bioethanol from the original hydrolysate obtained during oxalic acid pretreatment of lignocellulosic biomass. The bioethanol was separated and concentrated by pervaporation and the residue after pervaporation was evaluated for its antioxidant activity. Xylose (
) was the major product in the original hydrolysate. The original hydrolysate contained acetic acid, furfural and total phenolic compounds (TPC) as fermentation inhibitors. Acetic acid was removed by electrodialysis (ED), and
of bioethanol was produced from ED-treated hydrolysate. The TPC of ethyl acetate extracts from the residue obtained (OA-E) during pervaporation was 86.81 mg/100 g (extract). The
values of DPPH and ABTS radical scavenging activities, and reducing power of OA-E were
, respectively. Sugar degradation products and the phenolic compounds in OA-E were determined by GC-MS.
Changes of Furfural and Levulinic Acid Yield from Small-diameter Quercus mongolica Depending on Dilute Acid Pretreatment Conditions
Jang, Soo-Kyeong ; Jeong, Han-Seob ; Hong, Chang-Young ; Kim, Ho-Yong ; Ryu, Ga-Hee ; Yeo, Hwanmyeong ; Choi, Joon Won ; Choi, In-Gyu ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 838~850
DOI : 10.5658/WOOD.2015.43.6.838
In this study, dilute acid pretreatment was operated using small-diameter Quercus mongolica for evaluating the yield change of furfural and levulinic acid depending on pretreatment factors. The dilute acid pretreatment was conducted depending on reaction temperature (
), reaction time (10-30 min), and sulfuric acid concentration (0-2%, w/w). Then, glucose, XMG (xylose + mannose + galactose), furfural, and levulinic acid contents in the liquid hydrolyzate were measured and analyzed after pretreatment. Glucose content increased to 16.02% as reaction temperature, reaction time, and sulfuric acid concentration increased, but it decreased at the sulfuric acid concentration of 2% (reaction temperature: >
, reaction time: > 20 min). On the other hand, reaction temperature had a strong influenced on XMG content, and XMG content decreased to 1.63% through increasing of reaction temperature and sulfuric acid concentration, but XMG content was less affected by changes of reaction time. Furfural content increased with the increase of reaction temperature, reaction time, and sulfuric acid concentration, and maximum furfural content was 7.61% (reaction temperature:
, reaction time: 20 min, sulfuric acid concentration: 1%) based on a weight of raw material, while furfural content was dropped in more severe condition than in maximum furfural content condition. Levulinic acid content also increased with higher reaction temperature, reaction time, and sulfuric acid concentration. Especially, the sharp increase of levulinic acid content was observed above
, and maximum levulinic acid content was 10.98% (reaction temperature:
, reaction time: 30 min, sulfuric acid concentration: 2%). However, less than 1% of furfural and levulinic acid content was obtained in non-acidic catalyst condition that in whole conditions of reaction temperature and reaction time.
Manufacturing and Feed Value Evaluation of Wood-Based Roughage Using Lumber from Thinning of Oak and Pitch Pine
Kim, Seok Ju ; Lee, Sung-Suk ; Baek, Youl Chang ; Kim, Yong Sik ; Park, Mi-Jin ; Ahn, Byeong Jun ; Cho, Sung-Taig ; Choi, Don-Ha ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 851~860
DOI : 10.5658/WOOD.2015.43.6.851
The objective of this study was to manufacture the wood based roughage using lumber from thinning of oak and pitch pine (Pinus rigida). And the study also aimed to investigate a feed value evaluation of wood based roughages. To investigate the optimization condition of steam-digestion treatment for roughage, the wood chips of oak and pitch pine were steam-digestion treated at
under pressure 6 atm depending on treatment times (60 min, 90 min and 120 min) followed by the content of essential oils analyzed. The essential oil content of steam-digestion treated roughages for 90 min and 120 min were under 0.1 mL/kg. The evaluation of feed value was carried out from steam-digestion treated roughages for 90 min through feed chemical composition analysis, NRC (National research Council) modeling, ruminal degradability analysis and relative economic value analysis. The feed chemical compositions including DM (dry mater), CP (crude protein), EE (ether extract), NDF (neutral detergent fiber), ADF (acid detergent fiber), ADL (acid detergent lignin), NFC (nonfiber carbohydrate) in oak roughage were 95.4, 1.36, 3.11, 90.05, 83.85, 17.33, 6.50%, respectively, and in pitch pine roughage were 94.37, 1.33, 5.48, 87.89, 86.88, 30.56, 6.32%, respectively. Both roughages showed low level of protein and very high level of NDF. The TDN (total digestible nutrient) levels using NRC (2001) model in oak and pitch pine roughages were 40.55, 31.22%, respectively. The ruminal in situ dry matter degradability was higher in oak roughage (23.84%) than in pitch pine roughage (10.02%). The economic values of oak and pitch pine rough-ages were 235, and 210 \, respectively.
Fracture Toughness of Glass Fiber Reinforced Laminated Timbers
Kim, Keon-ho ; Hong, Soon-Il ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 861~867
DOI : 10.5658/WOOD.2015.43.6.861
The Compact Tension (CT) type test was performed in order to evaluate the fracture toughness performance of glass fiber-reinforced laminated timber. Glass fiber textile and sheet Glass fiber reinforced plastic were used as reinforcement. The reinforced laminated timber was formed by inserting and laminating the reinforcement between laminated woods. Compact tension samples are produced under ASTM D5045. The sample length was determined by taking account of the end distance of 7D, and bolt holes (12 mm, 16 mm, 20 mm) had been made at the end of artificial notches in advance. The fracture toughness load of sheet fiberglass reinforced plastic reinforced laminated timber was increased 33 % in comparison to unreinforced laminated timber while the glass fiber textile reinforced laminated timber was increased 152 %. According to Double Cantilever Beam theory, the stress intensity factor was 1.08~1.38 for sheet glass fiber reinforced plastic reinforced laminated timber and 1.38~1.86 for glass fiber textile reinforced laminated timber, respectively. That was because, for the glass fiber textile reinforced laminated timber, the fiber array direction of glass fiber and laminated wood orthogonal to each other suppressed the split propagation in the wood.
Adhesive Performance and Fracture Toughness Evaluation of FRP-Reinforced Laminated Plate
Jung, Hong-Ju ; Hong, Soon-Il ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 868~875
DOI : 10.5658/WOOD.2015.43.6.868
In order to replace existing slit type steel plate on the wooden structure joint, the FRP-reinforced laminated plates were produced. Four types of FRP-reinforced laminated plates were produced according to the type of reinforcement and adhesive, and before applying to the joint, the adhesion performance test according to KSF 3021 and KSF 2160 and the Compact Tension (CT) type fracture toughness test specified in ASTM D5045-99 were carried out. As a result of adhesion performance test, all GFRP textile, GFRP sheet, and GFRP Textile-Sheet type FRP-reinforced laminated plates satisfied the requirement of soaking delamination percentage with smaller than 5% based on KS standard. However, aramid type specimen satisfied the standard as the soaking delamination percentage of 4.8% but it did not satisfied the standard as the water proof soaking delamination percentage of 70%. As a result of fracture toughness test, the volume ratio of reinforcement to timber became 23% so that the strength of FRP-reinforced laminated plates increased by two to four times in comparison to the control specimen. It was confirmed that the GFRP Textile-Sheet type specimen was most resistant to the fracture most since the ratio of stress intensity factor compared with that of the control increased to 61% owing to the parallel arrangement of glass fiber to the load. As a result of tensile shear strength test using FRP-reinforced laminated plates and nonmetal dowels, it is about 12% lower than metal connectors.
Insulation Details and Energy Performance of Post-Beam Timber House for Insulation Standards
Kim, Sejong ; Park, Joo-Saeng ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 876~883
DOI : 10.5658/WOOD.2015.43.6.876
Han-green project, which pursues Korean style post and beam timber house with traditional construction technique of Han-ok, has been carried out in KFRI (Korea Forest Research Institute) since 2006. Recently, the improvement of its building energy performance was studied with energy-saving elements. This study was conducted to provide the insulation details of building envelopes in a post-beam timber house for recent enhanced insulation standards and following effect on building energy performance. The level of thermal transmittance (U-value) values of building envelopes was composed of two stages: present Korean insulation standards and passive house. To evaluate building energy performance, the building airtightness values of two stages was ACH50 =
for common domestic timber house constructed recently, and ACH50 =
for passive house. Consequently, four cases of the building energy performance according to the combination of U-value with airtightness were evaluated. The test house for evaluation was located in Seoul and its energy performance was evaluated with CE3 commercial building energy simulation program. The result showed that enhanced insulation from level I to II reduced
of annual heating energy demand regardless of airtightness.
Assessment on Thermal Transmission Property of Wall Through a Scaled Model Test
Chang, Yoon-Seong ; Kim, Sejong ; Shim, Kug-Bo ; Lee, Sang-Joon ; Han, Yeonjung ; Park, Yonggun ; Yeo, Hwanmyeong ;
Journal of the Korean Wood Science and Technology, volume 43, issue 6, 2015, Pages 884~889
DOI : 10.5658/WOOD.2015.43.6.884
Appropriate evaluation of thermal insulation property of structural member and valid control of cooling/heating energy are important for improving building's energy efficiency. The typical heating system of house in Korea is the floor heating one. The radiation heating system is not only appropriate to climate and geographic conditions of Korea, but also advantageous to provide emotional comfort by the warm feeling of floor. Based on living conditions in Korea, scaled models of the wooden house and concrete house were designed. The ceiling was made of styrofoam insulation and the four sided walls and bottom were made of plywood and concrete, respectively. The floor was heated by heating film. Indoor vertical temperature distributions by floor heating system were measured by thermocouple, and surface temperatures on walls were measured by infrared thermography. Also, thermal insulation property of wooden wall was evaluated to build database for improving energy efficiency of wooden building. It is expected that collected data during tests of various types of floor and wall composition could be referenced for evaluating thermal environment of actual conditions of houses.