• Korean Journal of Construction Engineering and Management
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• v.9 no.1
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• pp.77-86
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• 2008

On account of increasing interest of substantiality in these day, it is needed to make an effort to establish an environmentally sustainable production system for the construction works. Although practical affairs and researches are in progress to reduce and recycle construction wastes, as a result of a research, there are still obstructive factors on waste reduction and recycling which they don't interact efficiently between waste disposal process of the construction area and waste disposal company. As a plan to revitalize reduction and recycling of construction wastes, this research focuses on finding obstructive factors and giving solutions to reduce and recycle construction wastes which comes from construction process and construction industries. To meet the needs of the research, firstly relatively significant construction wastes (concrete, soil, brick, block, asphalt, plastic, lumber) were identified. On site level interviews with management of disposal companies and construction sites were conducted as well, focusing on typical waste disposal process. Throughout this interviews, obstructive factors were conducted. A result of the research, the authors suggest an improved approach on disposal and recycling for construction waste by prioritizing the identified factors and ranking the importance level of each factor. And, by identifying factors obstructing reduction and recycle of construction wastes, this research suggests improved disposal process of construction waste.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.5
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• pp.111-120
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• 2015

In this study, the general structure of the landscape architecture industry was considered through analysis of advertisements in the landscape architecture magazine, 'Environment & Landscape Architecture', and the transition process and factors of landscape facilities were analyzed. Based on this result, the direction of future landscape facilities and basic data were suggested. When analyzing the advertisements that have been published in 'Environment & Landscape Architecture' for 30 years, outdoor facilities were depicted at a frequency of 1,853 times and among them, rest facilities and convenience facilities were depicted 1,457 times and 378 times, respectively. The reason why outdoor facilities have a far higher advertisement frequency than other landscape facilities is they were highly influenced by the house construction-related government policy, which resulted from the expansion of the rest facility industry along with regional expansion to public design. Moreover, it was found that wood and steel were mainly used to make pergolas and benches, which are rest facilities, and polycarbonate, with high economic efficiency and durability, was used the most as a roofing material for pergolas. This study attempts to explore the tendency of landscape facilities and the changes in the detail of their types by analyzing the stream of landscape facilities diachronically, based on the advertisements published in a representative magazine of landscape architecture.

• The Journal of Engineering Geology
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• v.19 no.1
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• pp.63-70
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• 2009

The optical fiber cable acting as a sensor was embedded in the underground research tunnel and portal area in order to monitor their stability and the spatial temperature variation. This system includes two types of sensing function to monitor the distributed strain and temperature along the line, where sensor cable is installed, not a point sensing. According to the results of one year monitoring around the KURT, there is no significant displacement or movement at the tunnel wall and portal slope. However, it would be able to aware of some phenomena as an advance notice at the tunnel wall which indicates the fracturing in rockmass and shotcrete fragmentation before rock falls accidently as well as movement of earth slope. The measurement resolution for rock mass displacement is 1 mm per 1 m and it covers 30 km length with every 1m interval in minimum. In temperature, the cable measures the range of $-160{\sim}600^{\circ}C$ with $0.01^{\circ}C$ resolution according to the cable types. This means that it would be applicable to monitoring system for the safe operation of various kinds of facilities having static and/or dynamic characteristics, such as chemical plant, pipeline, rail, huge building, long and slim structures, bridge, subway and marine vessel. etc.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.1-10
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• 1992

Fresh fungi were collected during field trips to Ullung Island from August, 1990, to September, 1991. Among them, some polyporoid fungi were recognized to the species. Thirty three species were identified, among which nine fungi were confirmed new in Korea and registered here with descriptions. These fungi are Auriporia aurulenta, Ceriporiopsis gilvescens, Ceriporiopsis subvermispora, Gloeophyllum trabeum, Junghuhnia separabilima, Oligoporus stipticus, Oxyporus similis, Phellinus lavigatus, and Polyporus melanopus.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.31-41
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• 2016

Damage to structures, such as bridge piers, are increasing rapidly due to the debris moving along rivers at the time of flooding. Therefore, the debris fin, debris deflector and debris sweeper, which are debris reduction systems, were produced in this study and an accumulation experiment was carried out on the experimental channel according to the existence of the reduction system. The debris fin is the reduction system that creates parallel flow on debris accumulated on the bridge to pass through the bridge, which was produced using wood. In addition, the debris deflector was produced using steel pipes and it has the type of detouring the direction of debris. The debris sweeper passes the debris using the magnetic force rotation of a screw-shaped cylindrical structure by water flow and it was produced using acrylic material. The experiment was carried out by analyzing the level of accumulation according to the hardness and dropping method of the debris and comparing the accumulation rate of reduction systems, and the experiment was carried out 5 times. According to the experimental results, there was a difference in the accumulation rate according to the type of reduction system and the shape of debris, and it often depended significantly on the initial shape of debris accumulation. The direct debris reduction effect on the bridge was higher in the order of the debris deflector, debris sweeper and debris fin, but in case of the debris deflector, damage, such as stream turbulence, changes in water level and river bed, and the loss of deflector can occur due to debris accumulated directly on the debris deflector. Therefore, it is necessary to design the debris deflector considering these issues.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.231-236
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• 2014

Sawdust, produced as an wood by-product, is usable biomass as liquid fuels if decomposed to monomer unit, because the chemical structure are similar to high octane materials found in gasoline. In this study, parameters of thermochemical degradation by acetone-solvolysis reaction of sawdust such as the effect of reaction temperature, reaction time and type of solvent on conversion yield and degradation products were investigated. The liquid products by acetone-solvolysis from sawdust produced various kind of ketone, phenol and furan compounds. The optimum sawdust conversion was observed to be 88.7% at $350^{\circ}C$, 40min. Combustion heating value of liquid products from thermochemical conversion processes was as high as 7,824 cal/g. The energy yield and mass yield in acetone-solvolysis of sawdust was 60.8% and 36.4 g-oil/100g-sawdust after 40 min of reaction at $350^{\circ}C$, respectively. The major components of the acetone-solvolysis products, that could be used as liquid fuel, were 4-methyl-3-pentene-2-one, 1,3,5-trimethylbezene, 2,6-dimethyl-2,5-heptadiene-4-one, 3-methyl-2-cyclopenten-1-one as ketone compounds.

• The Korean Journal of Mycology
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• v.14 no.4
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• pp.257-263
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• 1986

So as to clarify the biodegradation mechanism of lignin, lignin biodegradability among four white-rot fungi, Pleurotus ostreatus 1,2,3, and Polyporus versicolor were compared each other by simple plate test method, so that P. ostreatus 2 and P. versicolor exhibited the most wide clear zone. And to investigate the degree of lignin depolymerization, they were grown in lignin­media where various carbohydrates were added, then that was analyzed through column chromato­graphy. In consequence, P. ostreatus 2 and 3 showed more excellent effect of lignin depolymerization among those 4 white-rot fungi, and also in culture media in which glucose, cellobiose and xylose were added. When culture filtrates of the same media were scanned at UV range, there were no peak at 280 nm in the culture filtrate of P. ostreatus 2 and 3 where glucose, cellobiose and xylose were added. At the same time, culture filtrate, in which lignin was only contained as a carbon source, showed browning in color, whereas culture media with glucose, cellobiose and xylose in addition to lignin became yellowish (that is, decolorization). From above results, it might be assumed that polymerization and browning of lignin were decreased and lignin biodegradability was increased, when grown in lignin media where various carbohydrates were added.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.646-652
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• 2016

Biomass is regarded as one of the promising energy sources to deal with the depletion of fossil fuels and the global warming issue. Biocrude-oil can be produced through the fast pyrolysis of biomass feedstocks such as wood, crops, agricultural and forestry residues. It has significantly higher viscosity than that of conventional petroleum fuel and contains solid residues, which can lower the spray and atomization characteristics when applied to the burner. In addition, biocrude-oil consists of hundreds of chemical species derived from cellulose, hemicellulose and lignin, and evaporation characteristics of the biocrude-oil droplet are distinct from the conventional fuels. In the present study, a numerical study was performed to investigate the evaporation characteristics of biocrude-oil droplet using a simplified composition of the model biocrude-oil which consists of acetic acid, levoglucosan, phenol, and water. The evaporation characteristics of droplets were compared at various surrounding air temperatures, initial droplet diameters, and ethanol mixing ratios. The evaporation time becomes shorter with increasing air temperature, and it is much sensitive to the air temperature particularly in low temperature ranges. It was also found that the biocrude-oil droplet evaporates faster in cases of the smaller initial droplet diameter and larger ethanol mixing ratio.

• Journal of Adhesion and Interface
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• v.16 no.4
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• pp.137-145
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• 2015

This study aimed to develop epoxy putty as a multi-purpose connection and restoration material that can be used for material-specific restoration work such as metal, wood, ceramics, earthenware and stone artifacts by replacing synthetic resins currently being used for preservation treatment of cultural assets. Existing synthetic resins have the issue of cutting force resulting from high strength, deflection resulting from long hardening time, contaminating the surface of artifacts through staining on tools or gloves and need for re-treatment resulting from material discoloration. Accordingly, paste type restoration material most widely being used in the field of cultural assets preservation treatment was selected and examined the property to select it as an object of comparison. Based on such process, epoxy putty was developed according to the kind of agent, hardener and filler. For the purpose of solving the issues of existing material and allowing the epoxy putty developed to have similar property, property experiments were conducted by selecting agents and hardeners with different characteristics and conditions. The study findings showed that both kinds are paste type that improved work convenience and deflection issue as a result of their work time of within 5~10 minutes that are about 3~10 times shorter than that of existing material. In regards to wear rate for increasing cutting force, it improved by about 3 times, thereby allowing easy molding. For the purpose of improving the issue of surface contamination that occurs during work process, talc and micro-ballon were added as filler to reduce the issue of stickiness and staining on hand. Furthermore, a multi-purpose restoration material with low shrinkage, low discoloration and high cutting force was developed with excellent coloring, lightweight and cutting force features.

• Journal of the Korean Geotechnical Society
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• v.35 no.1
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• pp.31-42
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• 2019

About 3% of Casein is included in milk and it accounts for 80% of milk's protein. It has an adhesive property when mixed with calcium hydroxide and sodium hydroxide solutions. It has been usually used to bond woods under dry condition but becomes weak when exposed to moisture. Such weakness is very critical when casein is applied for soil cementation under groundwater condition. Therefore, this study was aimed to protect such weakness by changing or adding certain ingredients of casein adhesive. Two types of cemented specimens were prepared with Nakdong river sand and tested for unconfined compressive strength and durability. Each specimen was mixed with casein or cement. Ingredients of casein binder suggested by the University of Wisconsin, which is called a standard casein recipe, was also prepared. This study tried 6 different types of casein binder recipe. Among them, one with 30% hydroxide calcium increase and 50% hydroxide sodium decrease compared with the standard casein was most effective. Based on the most effective casein recipe, cemented sand with 1-4% of casein ratio was prepared and tested. The unconfined compressive strength and durability index were 6,253kPa and 92% for the specimen with 4% of casein ratio and 1,500kPa and 62% for the one with 8% of cement ratio. Therefore, casein cemented sand showed better performance. In addition, over 3% of casein cemented sand had over 80% durability index.