• Economic and Environmental Geology
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• v.53 no.3
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• pp.287-296
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• 2020

Mine Reclamation Project is being carried out with the aim of ensuring a sustainable green living and helping to develop eco-friendly mines by analyzing, removing and preventing the harmful factors. Mines developed during the japanese colonial period and mining boom period are still not repaired throughout the country, and from these scattered risks, public safety is worth pursuing as a top priority. The project that is close to public safety in the mine recalmation project is an emergency treatment, and the most widely used method is a filling method similar to the ground subsidence prevention. If dangerous mine cavity or tunnels are located in the mountains, charging with existing materials may not be possible, or unreasonable cases may occur, and new methods of technological development are required. Emergency actions should be carried out safely and efficiently to prevent the loss of precious people's lives on the hiking paths adjacent to dangerous mining sites. In these field conditions, urethane foam materials may be an alternative. In this study, the applicability of urethane foam materials in mining was reviewed through overseas cases. It was also tested on the appropriate depth of top soil for the protection of urethane foam materials through forest fire simulation test. The test result show that approximately 15cm of soil covering (recommended 20cm over) was suitable for maintaining the function of foam materials from forest fires.

• Steel and Composite Structures
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• v.44 no.4
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• pp.503-517
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• 2022

This paper presents the mechanical buckling of bi-directional functionally graded sandwich beams (BFGSW) with various boundary conditions employing a quasi-3D beam theory, including an integral term in the displacement field, which reduces the number of unknowns and governing equations. The beams are composed of three layers. The core is made from two constituents and varies across the thickness; however, the covering layers of the beams are made of bidirectional functionally graded material (BFGSW) and vary smoothly along the beam length and thickness directions. The power gradation model is considered to estimate the variation of material properties. The used formulation reflects the transverse shear effect and uses only three variables without including the correction factor used in the first shear deformation theory (FSDT) proposed by Timoshenko. The principle of virtual forces is used to obtain stability equations. Moreover, the impacts of the control of the power-law index, layer thickness ratio, length-to-depth ratio, and boundary conditions on buckling response are demonstrated. Our contribution in the present work is applying an analytical solution to investigate the stability behavior of bidirectional FG sandwich beams under various boundary conditions.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.157-161
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• 2008

This experiment was conducted to make eatable fruit of oriental melon with peel, we covered oriental melon fruit with pear, apple and grape paper bag. Temperature inside paper bags was lower than air temperature in daytime but reversed in night. Relative humidity inside paper bags was higher than outside humidity in daytime but reversed in night. Covering with paper bags seemed to make fruit length shorter, fruit width narrower, flesh thickness thinner and fruit weight heavier but no difference was found among treatments. Soluble solid contents of flesh and placenta seemed lower with covering with paper bags but also difference did not find among treatments. Increasing of soluble solid contents of fruits was observed at 5 days after removing paper bags but not immediately at removing paper bags. Fruit hardness and chromaticity were dropped by covering paper bags. Decrease of fruit hardness by covering paper bags made more eatable with peel but more study have to be taken to improve chromaticity and soluble solid of fruits.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.67-73
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• 2019

We carried out basic research to evaluate covering material for improving and managing contaminated benthic environments in coastal areas. Changes in nutrient concentration such as phosphate, hydrogen sulfide of contaminated sediment, and pH, Oxidation Reduction Potential (ORP) were investigated through mesocosm experiments for 6 months by covering contaminated sediment with granulated coal ash. Calcium oxide eluted from the granulated coal ash was confirmed to neutralize acidified sediment by increasing pH through hydrolysis. Also, calcium oxide and silica eluted from the granulated coal ash adsorbed and precipitated with phosphate in the sediment. The concentration of phosphate in the sediment investigated decreased by ca. 84.31 %. Similarly, the concentration of hydrogen sulfide decreased by 133.5 mg/L in one month. The hydrogen sulfide is considered to have reacted with substances such as manganese oxide which were eluted from the granulated coal ash and precipitated. Also, it was concluded that the hydrogen sulfide was reduced since anaerobic conditions in the sediment weakened. According to the results of these mesocosm experiments, granulated coal ash was found to be effective to remediate and manage benthic environments by covering the surface layer of sediment.

• Journal of the Korean Solar Energy Society
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• v.28 no.3
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• pp.35-44
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• 2008

In this study, the experiment of the measuring of four different types of flooring materials' thermal characteristics was conducted and examined during the summer. The experimental materials were arranged on the existing slab of the roof, and then its thermal characteristics were examined from the point of view of thermal radiation analysis. The aim of this study is ultimately to draw the fundamental data for improvements in a building's thermal function and reduce the urban heat island phenomena through optimizing the thermal characteristics of the surface covering materials of a building. The results from this study are as follows; 1) Each experimental material's albedo was calculated as 0.83 on the aluminum panel, 0.40 on the rock block, 0.37 on the wood deck and 0.21 on the concrete. It shows that the concrete material, which has the lowest short wave reflective rate, absorbed the most radiation energy and the aluminium panel has absorbed the lowest radiation energy. 2) From the each experimental object's value of the long wave radiation, the concrete material measured the highest, at $628W/m^2$, and the aluminium panel measured the lowest at $412W/m^2$. Therefore, it verifies that the experimental objects' own radiation rate determines the amount of the long wave radiation. 3) The degree of energy absorbency of a building's surface covering materials is greatly influenced by its own albedo and radiation rate, Therefore, it needs to be considered for the improvements in a building's thermal function and reducing the urban heat island phenomena. 4) According to the evaluation result of the each experimental object's overall heat transmission screening function on the roof of a building, the wooden deck is proven to be an excellent material for excluding the outside temperature differences effectively with its characteristic of low heat capacity and conduction. Also its surface temperature on the roof slab and the temperature difference during the day were both measured at low.

• Korean Journal of Plant Resources
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• v.13 no.2
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• pp.147-153
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• 2000

Experiments were carried out to determine the effects of culturing conditions DCI(Day required for Colonization after Inoculation), CR(Contamination Rate), MD(Mycelial Density), DPI(Day required for Primordial sclerotia formation after Inoculation), yields, and degree of the foreign materials formations in Poria cocos sclerotia. The upper and bottom side of wood logs were covered with gauze, rice hull and floating leaves, vinyl, or covering cloth in order to prevent foreign material formations in p. cocos. The major results were positive in the order of rice hull, floating leaf, vinyl, gauze, and covering cloth covered and dwindled. In case of the upper and bottom sides of the wood logs covered with rice hull, DCI required 50 days more when compared with the control group(45 days) and CR was 0%, while the control group showed 2% CR. MD was excellent in case of conventional methods as against control's. DPI required 17~20 days less when compared with the control group(82 days). Yields of p. cocos in case of the upper and bottom side of wood logs covered with rice hull were 5.87kg, which is 35.7% higher than that of the control group(4.33kg), and 5.62kg in the case of upper sides cover only(increased by 29.8% compared with control), and 5.59kg in the case of bottom side cover only(increased by 29.1% compared with control), and foreign materials were none. In a separate experiment, where the upper and bottom sides of wood logs were covered with rice hull to prevent the foreign material formation, the results were as follows : Sclerotia formation status and quality of P. cocos were effective in the order of 20cm, 40cm, and 60cm of buring depth and dwindled. In 20cm of burying depth, DCI was shortened by 5 days and CR was none, while the control group showed 2% CR. MD was remarkably fine at the mulched conditions. DPI was shortened by 20 days when compared with the control(62 days).

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.3
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• pp.518-528
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• 2010

This study analyzes the work environment and the work clothes wearing conditions of shipyard painters. In addition to this, three types of experimental painting work clothes were evaluated by painters in terms of the material performance and wearing functions. The findings on the harmful painting work environmental factors were organic solvents, noise, heavy dust, high temperatures, and noxious fumes. The body parts damaged during painting operations were the skin, arms, whole body, and face. In general, the satisfaction with the wearing performance of work clothes for painting was low especially in regards to sweat absorbency, sweat permeability, body protection, covering, and the work motion suitability. The satisfaction with the wearing sense of painting working clothes (regardless of the type of material) was high in the order of movement comfort> sensual comfort> physiological comfort. The satisfaction in overall comfort according to the types of material was high in the order of nylon> SMS nonwoven fabric> SF nonwoven fabric.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.264-265
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• 2014

Currently, CO₂ existed in the air usually reacts concrete, and then CaCO₃ can be appeared. As time goes by, pH of concrete is decreased and corrosion of steel can be happened. This phenomenon is called carbonation. For preventing carbonation of concrete, various methods like using corrosion inhibitor, high compressive strength concrete, and enough covering depth are adopted. But these method are usually passive methods focused on corrosion of steel and have limitation on economic. Thus, as basic study for active method of carbonation, cement pastes with CO₂ reactive material (γ-C₂S, MgO) and GBFS were in accelerated carbonation, and the compressive strengths were measured. On the result, the compressive strength was improved better than non-carbonation. Through measuring the weight change using TG-DTA, as specimens were carbonated, according to decreasing of Ca(OH)₂ and Mg(OH)₂, CaCO₃ and MgCO₃ were increased. Therefore it can be shown that carbonation curing can be realized.

• Korean Institute of Interior Design Journal
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• v.16 no.4
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• pp.89-98
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• 2007

This paper studied the spatial factors activating the personal interaction based on case studies of $M\'{e}diath\'{e}ques$ in France. The spatial factors are analyzed into material factors and dematerial factors. The material factors have physical features in space and directly or indirectly activate the personal interaction. They consist of 8 elements including pocket space, balcony, atrium, stairs, elevators, windows, conference rooms and furnitures. The dematerial factors consist of 6 elements including polycentrism, continuance, mixture, interpenetration, dematerialization, transparency. They are compounded of material factors and explain them conceptually. But dematerial factors are abstract concepts. To provide reliability I confirm the relationship with dematerial factors by using a connections, topology, a phased depth of the Depthmap as the framework of the visual recognition of the space syntax covering the characteristic of dematerial factors. The result of the quantitative analysis human-behavior in $V\'{e}nissieux$ $M\'{e}diath\'{e}que$ and the result of applying the spatial factors of $M\'{e}diath\'{e}ques$ as the community center to the $V\'{e}nissieux$ $M\'{e}diath\'{e}que$ proved that the spatial factors are significant factors of the $M\'{e}diath\'{e}ques$ as the community center.

• Journal of Bio-Environment Control
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• v.21 no.1
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• pp.1-11
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• 2012

The objective of the present study is to provide data needed to find double covering method to be able to improve environment of temperature, humidity and PPF in tomato greenhouse. The distribution charts of temperature, humidity and PPF which were measured in environment control conditions such as thermal insulation, air heating, roof ventilation and air fog cooling in conventional and air inflated double layers greenhouses were drawn and analysed. The thermal insulation effect of the air inflated greenhouse was the same as that of conventional greenhouse because the temperature between insulation curtain and roof covering material was equal in heating season. The ventilation effect of the air inflated greenhouse was superior to the conventional greenhouse. The temperature distribution in the fog cooled greenhouse was uniform and the cooling effect was about $3.5^{\circ}C$. The condensation on the roof covering surface could be controlled by removing the moisture between insulation curtain and roof covering by using humidifier. The PPF of conventional greenhouse was more decreased than the air inflated greenhouse as time went by because the transmittance of conventional greenhouse declined by dust collected on the inside plastic film owing to rolling up and down operation for ventilation.