• Journal of Hydrogen and New Energy
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• v.30 no.2
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• pp.178-187
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• 2019

Due to the increasing demand of high rank coal, the use of low rank coal, which has economically advantage, is rising in various industries using carbonaceous solid fuels. In addition, the severe disaster of global warming caused by greenhouse gas emissions is becoming more serious. The Republic of Korea set a goal to reduce greenhouse gas emissions by supporting the use of biomass from the Paris International Climate Change Conference and the 8th Basic Plan for Electricity Supply and Demand. In line with these worldwide trends, this paper focuses on investigating the combustibility of high rank coal Carboone, low rank coal Adaro from Indonesia, Baganuur from Mongolia and, In biomass, wood pellet and herbaceous type Kenaf were simulated as kinetic reactivity model. The accuracy of the pore development model were compared with experimental result and analyzed using carbon conversion and tau with grain model, random pore model, and flexibility-enhanced random pore model. In row lank coal and biomass, FERPM is well-matched kinetic model than GM and RPM to using numerical simulations.

• Fire Science and Engineering
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• v.25 no.3
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• pp.78-84
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• 2011

In this study, we have measured the charring rate of solid sawn timber as a preceding step for develop performance based fire safety design method of wood framed building structures. The follows are the summary of fire test results carried out with $400{\times}400$ mm cross-section Douglas-fir in varied of thickness and grain directions. I) When the timber thickness increase under same dimension, the charring rate decreases gradually. It is seemed the charring layer up on a thickness roles as a insulation, gives combustion delaying time to specimen. 2) The charring rates measured at different depths (10, 20, 30, 40 mm) in timber which varying thickness (20, 40, 80, 120 mm) when exposed maximum 1 hour standard fire increase by 30 mm depth, but decrease at 40 mm. It is seemed the minimum charr layer should be 30 mm for having role of insulation. 3) The charring rate of cross section surface (direction of perpendicular to grain) was more high than that of grain direction. It can be explained by the cracks and gaps from greater charr contraction made more heat flux incident into timber.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.1
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• pp.1-10
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• 1984

This dissertation presents an exact solution for the shearing and normal stresses of an orthotropic plane body loaded by a pairtial-uniform shear load. The solution satisfies the equilibrium and compatibility equations concurrently. An Airy stress function is introduced to solve the problem related to an orthotropic half-infinite plane under a partial-uniform shear load. All the equations for orthotropy must be degenerated into the expressions for isotropy when orthotropic constants are replaced by isotropic ones. The author has evaluated all the equations of orthotropy and succeeded in obtaining exactly identical expressions to the equations of isotropy which were derived independently by means of L'hospital's rule. The analytical results of, isotropy ate compared with the simple results of other investigator. Since a concentrated shear load is a particular case of partial-uniform shear load, all the equations of partial-uniform shear load case are degenerated into the expressions for concentrated load case of isotropy and orthotropy. The formal solution is expressed in terms of closed form. The numerical results for orthotropy are evaluated for two kinds and two different orientations of the grain of wood. The type of wood considered are three-layered plywood and laminated delta wood. The distribution of normal and shearing stresses are shown in figures. It is noted that the distribution of stresses of orthctropic materials dependson the type of materials and orientations of the grain.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.559-571
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• 2017

This study was conducted to determine the adhesive performances of plywoods affected by layering direction and the amounts of thermoplastic films. The face and back layers of veneer were hardwood species (Mixed light hardwood) and core layer veneer was radiata pine (Pinus radiata D. Don). Thermoplastic film used as adhesive were polypropylene (PP) film and polyethylene (PE) film. Thermal analysis and tensile strength were investigated on each films. As a result, the melting temperature of PP and PE films were $163.4^{\circ}C$ and $109.7^{\circ}C$, respectively, and the crystallization temperature were $98.9^{\circ}C$ and $93.6^{\circ}C$, respectively. Tensile strength and elongation of each films appeared higher on the width direction than length direction. Considering the characteristics of the thermoplastic films, the test for the amount of film used was carried out by layering film to the target thickness on veneer. The effecting of layering direction of film on plywood manufacturing was conducted by laminating in the length and width directions of the film according to the grain direction of veneer. Tensile-shear strength of plywood in wet condition was satisfied with the quality standard (0.7 MPa) of KS F 3101 when the film was used over 0.05 mm of PP film and over 0.10 mm of PE film. Tensile-shear strength of plywood after cyclic boiling exceeded the KS standard when PP film was used 0.20 mm thickness. Furthermore, higher bonding strength was observed on a plywood made with width direction of film according to grain direction of veneer than that of length direction of film. Based on microscopic analysis of the surface and bonding line of plywood, interlocking between veneers by penetration of a thermoplastic film into inner and cracks were observed.

• Journal of the Korean Wood Science and Technology
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• v.8 no.1
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• pp.13-21
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• 1980

This experiment was carried out to investigate the effect of heating periods on the physical and mechanical properties of maple (Acer mono Max.) by oven heating and heating in water at 100$^{\circ}C$ for 0, 2, 4, and 6 days respectively. The results obtained are summarized as follows: 1. The green volume specific gravity due to oven heating decreased from 6 days of exposure, and that, due to heating in water decreased from 4 days of exposure. 2. The radial shrinkage due to oven heating decreased from 2 days of exposure, but that due to heating in water increased from 6 days of exposure. The tangential shrinkage due to oven heating decreased from 2 days of exposure, but that due to heating in water increased from 2 days of exposure. 3. The amount of water absorption due to oven heating decreased from 2 days of exposure, but that due to heating in water increased from 4 days of exposure. 4. The compressive strength pararelled to grain due to oven heating increased till 4 days of exposure but decreased from 6 days, and that due to heating in water decreased from 2 days of exposure. 5. The shearing strength pararelled to grain due to oven heating increased till 2 days of exposure, but decreased from 4 days of exposure, and that due to heating in water decreased from 4 days of exposure. 6. The bending strength due to oven heating increased till 4 days of exposure but decreased from 6 days, and that due to heating in water decreased from 6 days of exposure. The impact bending absorbed energy due to oven heating decreased from 4 days of exposure, and that due to hearing in water decreased from 2 days of exposure.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.69-78
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• 2008

Shearing strength test in tension type was investigated to determine the shear resistance of bolt and drift-pin connection of domestic larix glulam. The specimen was connected with bolt and drift-pin in the inserted plate type, and only bolt in the side plate type. The diameter of bolt and drift-pin used in the experiment are 12, 16 and 20 mm. The hole of bolt was drilled at the end-distance 5 d and 7 d. Tension load was loaded in the direction parallel to grain. The shear resistance was evaluated according to end-distance through this, the yield load was compared with the experimental yield load, using Larsen's formula. The prototype design strength is based on the yield load of end-distance 7 d and the reduction factor of end-distance 5 d was calculated. The results were as follows. 1. The average of maximum load of drift-pin connection was higher by 3~30% at the inserted type than at bolt connection with increasing diameter. In bolt connection, the average of maximum load of the side type was 1.54~2.07 times higher than that of the inserted type. In the same diameter, the average of maximum load of end-distance 7 d was higher by 8~44% than that of 5 d. 2. The bearing stress was 1.16~1.41 times higher at the inserted connection than at drift-pin connection, and 1.37~1.86 times higher at 7 d than at 5 d. Also, when the slenderness ratio was below 7.5 at drift-pin connection and below 6.0 at inserted connection, the lateral capacity was good. 3. The ratio of the experimental yield load and the predicted yield load calculated by Larsen's formula proposed by Larsen was 0.80~1.10 at inserted connection, and 0.75~1.46 at side connection. 4. When the inserted bolt connection was based on the yield load of end-distance 7 d, the reduction factor was 0.89 at 12 mm connection, 0.93 at 16 mm and 0.85 at 20 mm. The reduction factor was 0.89 at 12 mm the inserted drift-pin connection, 0.93 at 16 mm, 0.93 at 20 mm. The reduction factor was 0.79 at the side connection of the 12 mm bolt connection and 0.80 at 16 mm.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.290-300
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• 2014

In this study, cross-laminated woods were made with spruce wood and the effects of annual ring angles of perpendicular direction laminae on static bending strength performance were investigated. Static bending strength performances of parallel laminated woods with all layers composed of laminae perpendicular to the grain ($P_{\bot}$ type) were in the order of $90^{\circ}$ > $0^{\circ}$ > $45^{\circ}$. The MOE and MOR for the $45^{\circ}$ annual ring angle were 0.0989 GPa and 3.25 MPa, and it showed the lowest values. By placing longitudinal-direction laminae in the core of $P_{\bot}$ type, the strength performances were markedly improved. In the case of cross-laminated woods with perpendicular-direction laminae in the faces ($C_{\bot}$ type), the bending strength performances were in the order of $90^{\circ}$ > $0^{\circ}$ > $45^{\circ}$, but the differences among annual ring angles were less than those of the parallel-laminated woods. In the case of cross-laminated woods with perpendicular-direction laminae in the core ($C_{\parallel}$ type), the bending strength performances were in the order of $45^{\circ}$ > $90^{\circ}$ > $0^{\circ}$ unlike $P_{\bot}$ type and $C_{\bot}$ type. The MOE and MOR for the $45^{\circ}$ annual ring angle were 12.0 GPa and 55.8 MPa, and it showed the highest values.

• Journal of Conservation Science
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• v.18 s.18
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• pp.97-104
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• 2006

Absolute ages for three pieces of organic materials such as wood and shell were determined with radio-carbon concentrations and two potsherds with thermoluminescence measurements. Radiocarbon contents of each sample were compared with those of modern standard oxalate(NBS SRM4990C) and calculated radiocarbon ages of them. Quartz grains with diameter of $90\sim150{\mu}m$ were extracted from potsherds and used for measuring the archaeodose. Annual dose were calculated with measuring the alpha count rates and water contents and analysing $K_2O$ concentration of both potsherds and soils. Radiocarbon ages of organic materials were in the ranges of $4\sim2C$ BC and Quartz grain techniques for thermoluminescence dating showed 170 BC ud 210 BC respectively. It was found that the results of radiocarbon dating and TL dating were accorded with each other. But the deviations of TL dating have shown 13% and 20% respectively. It need to reduce the deviations.

• Journal of the Korean Wood Science and Technology
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• v.6 no.2
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• pp.3-19
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• 1978

Five species, Abies koreana Wilson (A. koreana), Castanopsis cuspidata var. Sieboldii Nakai (C. Cuspidata). Machilus thunbergii Sieb. et Zucc. (M. thunbergii), Styrax japonica (S. japonica), and Quercus acuta Thunberg(Q. acuta) growing in the southern part of Korea were selected for the investigation of wood properties. In order to evaluate the wood properties of these five species, anatomical, physical, mechanical, chemical and pulping characteristics were investigated. And this study also covered wood technological problems related to the drying, gluing, debarking, flooring, and wood workability so that these species might serve to the best advantage. The results obtained were summarized as follows: 1. The trunk of A. koreana with many knots was straight. However, the trunks of S. japonica and C. cuspidata were crooked. 2. A. koreana showed the longest and the widest ill the fiber morphology; 2.97mm in length, 39.3${\mu}$ in width. In general, fiber width of all the species investigated were greater than those of other Korean hardwoods. 3. The specific gravity of Q. acuta was 0.74${\pm}$0.03, and that of A.koreana was 0.34${\pm}$0.02. The range of specific gravity of the other species was 0.47-0.52. 4. The adsorption of water was propotioned inversely with the specific gravity, but the adsorption of humidity was proportioned with the specific gravity. In spite of their medium density, S. japonica showed the greatest adsorption, and M. thunbergii the least. The water adsorption of cross section was twice greater than that of lateral direction, and there was a slight difference in between the radial and the tangential direction. 5. Shrinkage for tested five species was ranged from 5.36 to 10.24% in tangential direction, and 2.83~6.13% in radial direction. Q. acuta recorded the greatest shrinkage rate, and A. koreana the least. The greater was the specific gravity, the larger was the shrinkage rate. 6. The mechanical properties of Q. acuta were similar to those of Quercus mongolica which grow in Kangwon-Do. Strength properties of C. cuspidata, M. thunbergii, A. koreana were equivalent to those of other Korean commercial woods with similar specific gravity, except S. japonica which showed slightly higher strength than that of other species with similar density. 7. Higher glue joint strength for urea and phenol adhesieves was recorded in the species of M. thunbergii and C. cuspidata, however, high-density species(Q. acuta) and even low-density species(A. koreana) did not show good joint strength. 8. The attractive figure of M. thunbergii in texture seemed to he appreciated for decoration. And the grain and texture of other species were proper for furniture and building materials. 9. All of the species except Q. acuta were considered good for wood workability. 10. The denser the specific gravity was, the longer the drying time took. However, severe drying defects were formed in M. thunbergii whose density was medium. 11. All the species were considered suitable for the flooring wood expect A. koreana whose density was light. 12. Pentosan component in all the species was great, and the amount of extractives in Q. acuta was worth noticing. 13. Yield in kraft pulp was above the level of economic pulp yield, i.e. 45% in all species. 14. Debarking was easy in the species of A. koreana and M. thunbergii, and debarking after being boiled in water was the most efficient in all species.

• Journal of the Korean Home Economics Association
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• v.29 no.2
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• pp.87-120
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• 1991

The purpose of this study was to identify the design characteristics of the multi-leveled chest(jang) which was the main furniture of the master bedrom(anbang) in the Chosun Dynasty. The major findings and conclusions were: 1. The front view of the multi-leveled chest were composed of a protruded top panel(kaepan), drawers, folded doors, sectional panels(chwibyok kan and morum kan) and base stand(madae) in general. Variety in the front view found more frequently in single level chests than bi- or tir-level chests. 2. The overall dimensions of each type of chest increased with increase in number of levels, but the height of the sectional parts decreased. That is, the overall proportion of the single level chests were 10 : 9, bi-level chests were 5 : 6, and tri-level chests were 2 : 3. The proportion of 1 : 1, 4 : 5, 1 : 3, 1 : 4, 1 : 5 were found often in the sectional parts such as drawers, doors, chwibyok kans and morum kans. 3. In general, the surface treatments were subtle. Carved or inlayed ornamentation were seldom seen, and most chess were finished with clear lacquer to show the natural wood grain. There were no distinctive characteristics of surface ornamentation characteristic of any one type of chest. 4. The general patterns of the metal ornaments were spade(yowidu), round, bow, rectangular(yakgua), bat and flower shapes. The multi-level chests were decorated with more metal ornament types compared with the single-level chests. 5. In conclusion, there was more variety in all the design elements in the single level chests compared with the other types of chests. The bi-and tri-level chests were quite stylized in composition, size, proportion, surface treatment, and metal ornamentation.