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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Wood Science and Technology
Journal Basic Information
Journal DOI :
The Korean Society of Wood Science Technology
Editor in Chief :
Volume & Issues
Volume 26, Issue 4 - Dec 1998
Volume 26, Issue 3 - Sep 1998
Volume 26, Issue 2 - Jun 1998
Volume 26, Issue 1 - Mar 1998
Selecting the target year
Effects of Transducer Position in Ultrasonics Nondestructive Tests of Finger-Jointed Lumber
Jang, Sang-Sik ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 1~6
Studies on the Technical Development of Traditional Korean Golden Varnish (Hwangchil)(II) - Chemical Composition and Coatings-oil Characteristics of the Exudates and Bark-extractives of Hwangchil-namu(Dendrogapax morbifera Lev.) -
Lim, Kie-Pye ; Jung, Woo-Yang ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 7~13
In order to reconstruct the traditional technology of Korean golden varnish(Hwangchil) made from the exudates of D. morbifera, this study in the second step was carried out to analyze the chemical composition and oil properties of the exudates for coatings and bark extractives made from the trees of D. morbifera more than 20 years old grown in Wando and Jejudo islands in the southwestern part of Korean peninsula according to the physiological seasons. The results obtained are as follows: 1. The exudates appeared to be a phytoalexin because it exudated after several days in tapping only in summer season. 2. Both the exudates and bark-extracts with acetone contained 50~60% unsaponifiables and 30~50% saponifiables 3. A major component of essential oil in bark-extractives was
-cubebene and reached to 60~80%, while that of exudates included only 34%
-cubebene and some other compounds such as
-cadinene of 12%, aromadendrene of 9%,
-selinene of 9%, CAS030021-74-0 of 10%, etc. in GC-MS spectrometer. 4. A mjor component of fatty oil fraction in bark-extractives was linoleic acid and reached to more than 60%, while the exudates had mostly other components such as terpenes and phenolics instead of fatty acids accordint to GC-MS spectrometer. 5. Iodine value of samples after oil refining had 214mg/g in the exudates and more than than 150mg/g in bark-extractives, so the latter belonged to a drying oil.. 6. Therefore, the exudates from D. morbifera for traditional Korean golden varnish seems to have beeen used to a good varnish because it has some specific compounds different from its bark-extractives or general varnishes.
Use of Polyethylene as an Additive in Plywood Adhesive
Oh, Yong-Sung ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 14~18
A low density polyethylene(LDPE) was examined as an additive in phenol-formaldehyde(PF) resin adhesive for bonding radiata pine plywood. The LDPE was supplied by the commercial manufacturer. The LDPE was compared to a commercial filler commonly used in structural plywood adhesives in the United States. The adhesive mixes were made by following the recommended procedure of Georgia-Pacific Resins Inc.. using plywood-type PF resin. A total of 48 three-ply plywoods. 6.3 mm nominal thickness and 30 by 30 em in size, were made at two press times (4 and 5 min). two press temperatures (150 and
) and 30 minute assembly times for four adhesive mixing types. Evaluations of the LDPE addition were carried out by performance tension shear tests after two cycle boil aging tests on plywood per the U.S. Product Standard PS I-83. After accelerated-aging tests. plywoods were exhibited no delamination. The test results included tension shear strength and estimated wood failure values. The plywood test results support the use of polyethylene as an additive in plywood adhesives.
Effect of Sawdust Culture on Oak Mushroom, Lentinula edodes (Berk.) Pegler by Inoculation of the Liquid Spawn
Lee, Tai-Soo ; Cho, Nam-Seok ; Min, Du-Sik ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 19~28
For cultivation on sawdust-bed of oak-mushroom until present time, inoculation of spawn on sawdust bed has been performed by sawdust spawn. But, liquid spawn may have advantages for rapid mass production of spawn, and now, sawdust-cultivation by liquid spawn inoculation should be applied instead of sawdust spawn. Therefore, investigations were performed to evaluate the effect of sawdust-cultivation by liquid spawn inoculation. The results were as follows: 1. When 11 kinds of liquid media were applied, the oak-mushroom culture medium was the most excellent in growth. Most suitable temperature at PDA was
in range were optimal for liquid culture. In liquid culture, amount of mycelial growth increases rapidly up to 40 days of cultivation. Incubation at fermentor brought yield of 106mg dry mycelia per 40ml media after 17 days. 2. In 1l-spawn bottle, growth of mycelium by inoculation of 20ml-liquid spawns were faster than 6g-sawdust spawn in spread of mycelia. On 2kg-bag culture, inoculations of 10ml-, 20ml- and 30ml-liquid spawns were all slower than 20g-sawdust spawn in mycelial spread. So, amount increasement in ampunt of liquid spawn should be discussed. Yields of mushrooms until third sproutings of 2kg-bag culture were 580g in 30ml-liquid spawn inoculation, but 510g, 486g and 470g from 20g-sawdust spawn, 20ml-liquid spawn and 10ml-liquid spawn, respectively. Thus, 30ml-liquid spawn inoculation was highest in yield.
Ultrafiltration and Adhesive Characteristics of Alkali-soluble Extracts from Radiata Pine Barks
Cho, Nam-Seok ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 29~37
Alkali-soluble extracts were prepared from medium-sized barks of Radiata pine(Pinus radiata). There are difficulties in the production of extracts with uniform quality and in the preparation of adhesives with suitable viscosity. Ultrafiltration using an Amicon cell was subjected to fractionate extracts according to molecular sizes in order to overcome the above problem. The filtration efficiency was studied by using thin channel filtration systems. Adhesive manufacturing was also examined. Removal of particles greater than 0.45m from the extracts increased both filtration speed (flux) and yields of solids in the filtrates. Ultrafiltration with PM 10 membrane was very effective to fractionate and concentrate the extracts. Stiasny precipitates from the filtrates obtained by PM 10 membrane were very lower than that(83%) of the retentates. This ultrafiltration method was efficient for obtaining high yield purified phenolic compounds(mainly polyflavanoids) and thus important for preparing wood adhesives from barks. The extracts were shown excessive high viscosities at the concentrations required for adhesive formulation, but this high viscosity and short gelation time was reduced by lowering pH of the extracts and addition of urea. The highest bonding strength of plywoods(340g/
of adhesive spreads) was achieved with adhesive formulated by 100parts of mixed alkali extracts and urea(70/30,w/w), 10parts of p-formaldehyde and 3.5parts of wheat flour at pH 6, and by hot pressing at the conditions of 12kg/
for 10 minutes.
Effects of Laser Parameters and Workpiece Conditions on Cutting Characteristics of Solid Wood and Wood-based Panel(II) - Specific Cutting Energy and Surface Qualities -
Sim, Jae-Hyeon ; Jung, Hee-Suk ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 38~50
Laser cutting tests were conducted to investigate the laser cutting characteristics of solid woods such as 25mm-thick white oak(Quercus acutissima) and maple(Acer mono), and wood-based panels such as 15mm-thick medium density fiberboard and particleboard. Test variables were laser power, cutting speed, grain direction, and moisture content. Specific cutting energy was measured and the qualities of cut surface were estimated in constant laser power. Specific cutting energy of white oak was larger than that of maple, and specific cutting energy of medium density fiberboard was smaller than that of particleboard. For both white oak and maple, specific cutting energy of green wood was smaller than that of air-dried wood because weight loss of moisture evaporation in green wood was larger than that in air-dried wood. In laser-cut surface, wood cells were not deformed and damaged, but in circular saw-cut surface fibers were pushed out and cut, and wood cells were deformed severely. However, mechanical surface roughness of saw-cut surface was smoother than that of laser-cut surface because of the existence of undeformed cell cavity in laser-cut surface.
A Study on the Deveopment of Wha Seon Ji (Painting Paper) - Blot of China Ink and Organic Test -
Cheon, Cheol ; Kim, Seong-Ju ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 51~56
The bast fiber of paper bush misumada have been cultivated in south coast bay of the Korean peninsula were not used to handmade painting paper. Therefore, in using the bast fiber of paper bush misumada manufactured handmade painting paper, tested absorption speed, blot characteristics and organic functions. The results are summarized as follows; The handmade painting paper manufacured only the bast fiber of paper bush misumada proper to the absorption speed of China ink, didn't have difference of the length and width for blot. And it was most fitted to east writing-and-painting using. Also the flexibility excell, and light and shade in overpainting directly appeared, and fitted to black-and-white drawing. And the using increase plan of the paper bush misumada demanded.
Copper Uptake by Tyromyces palustris
Son, Dong-Weon ; Lee, Dong-Heub ; Kang, Chang-Ho ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 57~62
In this research, the removal or uptake of heavy metals such as coppers by using oxalic acid metabolism of wood rot fungi, Tyromyces palustris were endeavored. As results, the addition of oxalic acid to copper containing culture did not cause the mycelium growth, but Tyromyces palustris was able to grow in this culture without inhibition. Tyromyces palustris grew with the cicular halo type in copper containing culture, and this type was formed as collectives after examining by microscope, and considered as copper oxalates by analyzing FT-IR comparison experiment with standards. According to this result, Tyromyces palustris has secreted oxalic acid during incubation, this secreted oxalic acid was combined with coppers, and formed copper oxalates by chelating reactions. In other words, the oxalic acid was might be as non-toxifying agent of coppers in medium. By using this copper removal mechanisms, Tyromyces palustris immobilized sawdust was used in bench scale air lift system for removing coppers. The added coppers were almost removed from the system within 72hrs. Therefore, this nonenzymatic wood degradation mechanism may give a possibility for removing coppers from copper containing waste water.
The Relationship between Anatomical Characteristics and Compression Strength Parallel to Grain in Major Species of Lepidobalanus
Oh, Seung-Won ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 63~69
This study was carried out to get some basic information on mechanical properties of Korea Lepidobalanus for rational utilization of wood. Five species of Quercus variabilis, Q. aliena, Q. serrata, Q. mongolica, Q. acutissima belong to Lepidobalanus were investigated in this research. Relationship of anatomical characteristics to compression strength parallel to grain was analyzed using stepwise regression technique. All possible combination of 21 independent variables were regressed on compression strength parallel to grain. The summarized results in this study were as follows: I. In the proportion of wood structural elements, the factors that had the greatest influence on compression strength parallel to grain appeared to be proportion of ray in earlywood in Q. variabilis and Q. acutissima, proportion of wood fiber in latewood in Q. aliena and Q. serrata and proportion of vessel in earlywood in Q. mongolica respectively. 2. In the size of wood element and its structure, the factors that had the greatest influence on compression strength parallel to grain were microfibril angle in Q. variabilis, Q. serrata and Q. mongolica and length of wood fiber in Q. aliena and Q. acutissima.
Studies on Physical Properties of Wood-based Composite Panel with Recycled Tire Chip - Change of Properties on Composite Panel by Mixing Ratio of Combined Materials -
Lee, Weon-Hee ; Byeon, Hee-Seop ; Bae, Hyun-Mi ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 70~75
In this paper, the relationships between volumetric mixing ratio of rubber chip and physical and mechanical properties of wood/rubber composite panel was examined in order to investigate the mixture characteristics of wood and rubber chip. Because of the specific gravity of rubber differed from wood chip, physical properties of wood/rubber composite panel was shown very different values by mixing rate of chip element. Specific gravity in air-dry of composite panel was increased rapidly as volumetric percent of rubber chip was increased. Moisture content of composite panel was decreased as volumetric percent of rubber chip element was increased. This results was considered that wood weight is light and porosity material for moisture absorption. Compressive strength and modulus of rupture in bending test were decreased as volumetric percent of rubber chip increased. By mixing ratio control of chip elements, various wood/rubber composite panel can be applicable to every interior materials such as subfloor, playground, and exterior materials such as road blocks for recreational facilities in garden and forest and city parks.
Effects of Process Variables and MAPP Coupling Agent on Properties of Wood Fiber-Polypropylene Fiber Composite by Turbulent Air Mixing
Yoon, Hyoung-Un ; Park, Jong-Young ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 76~86
Effects of processing variables and MAPP (maleic anhydride polypropylene) coupling agent on the properties of composite were discussed for turbulent-air-mixed woodfiber-polypropylenefiber composites. In this research, density, composition ratio, and mat moisture content were established as processing variables, and emulsified MAPP prepared by direct pressure method was incorporated as the coupling agent. And the turbulent air mixer, which was improved in function through alteration of our previous fiber mixer, was used to mix wood fibers and polypropylene fibers. At the addition level of 1% MAPP, based on oven-dried wood fiber weight, woodfiber-polypropylenefiber composites generally showed enhanced the physical and mechanical properties. And composites with low to medium densities of 0.6 to 0.8g/
greatly increased in these property values than with high densities of 1.0g/
or more by adding 1 % MAPP. Thus, MAPP addition was thought to be an effective way of enhancing properties for nonwoven web composites. At the mat moisture contents of 5 to 20%, however, the physical and mechanical properties were not enhanced by adding 1% MAPP. In the composites containing 15% polypropylene fibers, the lowest thickness swelling and water absorption values were observed at the 1% MAPP level. The addition of more than 1% MAPP had the adverse effect on the physical and mechanical properties of composites.
Bending Performances of Radiata Pine Veneers and Phenol Resin-Impregnated Sheet Overlaid Plywoods by Nondestructive Evaluation
Suh, Jin-Suk ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 87~96
The bending performances were evaluated at the radiata pine plywood through veneer compositions encompassing veneer quality, ply-numbers and overlays of the high density- or medium density-phenol resin impregnated sheets (hereafter abbreviated as resin sheets) on the raw plywood. In addition, a prediction on the bending MOE of veneers and plywoods was carried out by the nondestructive testing with stresswave timer. The summarized results were as follows: I. Bending strength and bending MOE of resin sheets-overlaid plywoods in parallel surface grain direction through 5 and 7ply were increased by 13 to 45% and 17 to 34%, respectively. Resin sheets-overlay occurred an increasing effect of the strength efficiency i.e. strength perpendicular-to-grain direction versus that parallel-to-grain direction, showing the phenomenon that the plywood strength becomes greater at the perpendicular-to-grain direction of 7ply than at that of 5ply. Displacement at bending failure had a greater trend at 7ply than at 5ply, and was decreased by resin sheets-overlay. 2. After the nondestructive bending MOEs were measured for individual veneers, these veneers were rearranged in plywood-manufacture. In these plywoods, including resin sheets-overlay, the actual MOE was predictable with feasibility of
=0.53, and also the nondestructively-evaluated MOE was lower by 20% in raw plywood, and higher 20% in LVL than actual bending MOEs.
Manufacturing of High Water-Resistant Particleboard by Combining Use of Urea Resin and EMDI Resin
Park, Jong-Young ;
Journal of the Korean Wood Science and Technology, volume 26, issue 1, 1998, Pages 97~105
This study examined the combined using effects of urea-formaldehyde (UF) resin and emulsifiable methylene diphyenyl diisocyanate (EMDI) resin to overcome performance limit of three-layer particleboards commonly made by UF resin. Two adhesive adding methods were applied with three types of resin combination system to each layer of particleboards. The one was simultaneously spreading method with emulsified compound resin (UF and EMDI) while the other was separately spreading method with unemulsified EMDI resin after UF resin spreading. The performance of particleboards bonded with 2% EMDI resin to the inner layers(IL) were similar to that of controls bonded with 8% UF resin. In the case of the emulsified compound resin application to the all layers of particleboards, there were marked reinforcing effects of EMDI resin, although a small amount of EMDI resin was mixed with UF resin. Especially bending MOR after 24 hours cold water-immersion and thickness swelling after 2 hours hot water-immersion of compound resin-bonded particleboards were remarkably different from those of pure UF resin-bonded particleboards. It was found that separately spreading method with unemulsified EMDI resin was more effective than simultaneously spreading method with emulsified compound resin to sustain the internal bond strength of particleboards after 24 hours cold water-immersion. In the resin combination systems to outer layers/inner layers of particleboards, water resistance and strength properties were superior in order of UF+EMDI/UF+EMDI > UF/UF+EMDI > UF/UF. And water resistance of particleboards was greatly dependent upon EMDI resin level in any adhesive adding method.