• The Journal of the Korea Contents Association
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• v.15 no.7
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• pp.282-288
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• 2015

A monte carlo simulation about shielding material and thickness of the syringe shield for radiation shield was performed. As a result of analysis, high atomic number materials such as tungsten, lead and bismuth have the highest shielding effect. However, $^{18}F$, $^{67}Ga$ and $^{111}In$ show high energy distribution in the region with thin shielding thickness. As the thickness of shielding materials increased, the energy distribution decreased due to reduction of ${\gamma}$-ray. In the case of low atomic number materials, they, showed energy distribution from highest to lowest, were barium sulfate, steel, stainless, iron and copper. Aluminum, plastic, concrete and water showed diverse aspect. they showed relatively high energy distribution because of increased ${\gamma}$-ray that penetrate the shield.

• Journal of the Korean Geosynthetics Society
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• v.4 no.1
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• pp.7-15
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• 2005

In recent years, the geotextile tubes filled with dredged material have been used in dike and breakwater construction for a number of projects around the world, and their use in this field is growing very fast. One of the most attractive advantages of geotextile tube technology is can be use the in-situ filling materials by hydraulic pumping, it can be also established lower costs and fast construction than other technology. Geotextiles form one of the two largest groups of geosynthetics and it is commonly made by two major types of polymer material(Polypropylene, Polyester). The objective of this paper is to examine several issues associated with drainage function and feasibility of geotextile tube structure such as filtering efficiency, dewatering efficiency, and filling process with polymer materials. Based on the laboratory filtering test and in-situ tests, polypropylene goetextile is more effective for drainage function of geotextile tube technology.

• Resources Recycling
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• v.25 no.1
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• pp.31-39
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• 2016

Small household appliances such as electric rice cooker, a vacuum cleaner, an electric fan, etc. are diverse and complex due to the materials and components and waste streams from the manufacturing processes. In the present study, physical characterization of small e-wastes was analyzed on major items including electric rice cooker after manual dismantling. Small household appliances is an important potential source of waste plastic, however, recycling plastics from small e-waste is still unusual. The present communication gives results of separation processes on black plastics and the limitations of these sorting processes in used small household appliances.

• Analytical Science and Technology
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• v.35 no.3
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• pp.116-123
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• 2022

Polymer bags, metallic canisters, and glass bottles have been used as containers for analyzing the volatile organic compounds (VOCs) in air. In this study, various sampling containers were compared to investigate the short-term stability of VOCs, that is, from the time they are sampled to the time they are analyzed. Polyvinyl fluoride (PVF), polypropylene (PP), polyester aluminum (PE-Al) bags, canisters, and glass bottles were used as sample containers. A 100 nmol/mol standard gas mixture of benzene, toluene, ethylbenzene, m-xylene, styrene, and o-xylene was used for the VOC comparison. Changes in the concentrations of samples stored for 10~20 day in each container were measured using a thermal desorption-gas chromatograph-flame ionization detector (TD-GC-FID). As a result, VOCs stored in a canister and two kinds of amber glass bottles have shown immaterial decreases in concentration in one week, and more than 80 % of the initial concentration was maintained for two weeks. In the case of polymer bags, the concentration of all VOCs, except benzene and toluene, were remarkably decreased below 70% of the initial concentration in one day. Particularly, ethylbenzene, xylene, and styrene have shown dramatic decreases in concentration below 30 % of the initial concentration in all polymer bags in one day.

• Korean Journal of Agricultural Science
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• v.29 no.2
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• pp.67-77
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• 2002

This study aims at investigating the realities of tractor rotary tilling and paving operations performed by farm families in the central part of the country, measuring the power requirement so as to find the energy-saving factors for tractor rotary tilling, and designing a device to prevent soil adherence to the inside of the rotary cover-this part is the most subject to soil adherence and affects the power requirement. As a result of rotary tilling tests using rotaries equipped with a soil adherence preventer, the power requirement values were measured to be 52.18, 52.44, 49.01 and 46.34 PS for general, stainless steel, rubber and PE rotaries, and as a results of measurement of the quantities of the soil adhered to rotaries after their tilling tests, on the average, the quantities were measured to be 5.6, 5.7, 3.1 and 2.7kg for general, stainless steel, rubber and PE rotaries, respectively. The PE rotary cover reduced the power requirement and soil adherence by 11 and 52%, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.513-513
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• 2012

핵 융합로의 대면재질(Plasma Facing Material; PFM)은 고온의 플라즈마와 고 에너지의 이온들에 지속적으로 노출 된다. 특히 PFM은 흡착되는 기체 등에 의한 부식과 변형이 발생할 수 있다. 현재 핵 융합로 내부의 PFM으로 고려되고 있는 재질 중 하나인 고순도 탄소타일의 경우 고온의 수소동위원소 플라즈마에 직접적으로 노출되므로 이에 의한 탄소타일에 흡착되는 수소 등의 기체에 대한 정량적인 분석방법이 필요하다. 본 연구는 고순도 탄소타일 등과 같은 플라즈마 대면재료에 흡착되어 있는 물질의 정량적 분석이 가능한 TDA (Thermal Desorption Analyzer)의 개념 설계에 관한 것이다. TDA는 고온 가열($800^{\circ}C$ 이상) 및 시료 장착부 및 초고진공(~10-9 torr) 및 측정부의 두 부분으로 구성 하였다. TDA 설계시 고온 가열 및 시료 장착부는 시료 내부에 흡착되어 있는 기체의 효과적 탈착을 위한 가열 및 시료의 모양에 영향을 받지 않는 장착방법, 시료 장착부의 outgassing rate를 최소화 하는 재질 선정 등을 고려하였으며, 초고진공(~10-9 torr) 및 측정부는 초고진공 유지방법, 터보펌프 배기속도 실측을 위한 구조, 진공측정 ion 게이지, 잔류가스분석기(Residual Gas Analyzer)의 최적위치 설정 등을 고려하여 설계하였다. 개념 설계된 TDA에 대하여 발표하고자 한다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.425-432
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• 2021

In this paper, We produced supporting for ginseng cultivation facilities as a material recycling product of CPW(Complex Plastic Wastes, CPW) from households. And we analyzed the characteristics of material recycling products according to the amount of r-LDPE(Recycled low density polyethylene, r-LDPE) used. As a result, as the amount of recycled LDPE used increa sed, the tensile strength a nd elonga tion of ma teria l recycled products using CPW increa sed, but a sh decrea sed. When the recycled r-LDPE usage is 5% or more, the physical properties of the material recycling product using CPW stably satisfy the quality standard (GRM 3093-2021) of supporting for ginseng cultivation facilities.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.3
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• pp.185-195
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• 2021

The flapping-wing micro air vehicle (FW-MAV) in this study utilizes the cambered wings made of quite flexible material. Similar to the flying creatures, the present cambered wing uses three different materials at its leading edge, vein, and membrane. And it is constrained in various conditions. Since passive rotation uses the flexible nature of the wing, it is important to select an appropriate material for a wing. A three-dimensional fluid-structure interaction solver is developed for a realistic modeling of the cambered wing. Then a parametric study is conducted to evaluate the aerodynamic performance in terms of the elastic modulus of leading edge and vein. Consequently, the elastic modulus plays a key role in enhancing the aerodynamic performance of FW-MAVs.

• Journal of Conservation Science
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• v.35 no.3
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• pp.245-251
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• 2019

In this paper, conservation treatment processes for the wooden furniture in the Presidential Archives are introduced. Conservation treatment strategies for modern wooden cultural heritage have been increasingly studied. The current study uses materials similar to those used by the existing conservation treatment method. Material analysis showed that the chair(Lee136-2) and desk(Yun37) in the Presidential Archives are made of Dipterocarpaceae, and both are coated with two layers of varnishing. FT-IR analysis showed that the varnish has a similar spectrum to that of a nitrocellulose-based lacquer(Lee136-2) and top coat(Yun37) and confirmed that a synthetic material was used. Pollutants had adhered to the surface of the wooden furniture and it was also in structurally unstable condition because of cracks and damage to the varnish and wood. Therefore, a conservation treatment was carried out to restore the damaged areas to their original appearance using similar kinds of materials, based on data obtained by materials analysis.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.1
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• pp.7-13
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• 2016

As the foods and household manufacturing technology is developed, the packaging method of products is being changed from single to multi materials and layers. This study were focused on EPR carton packaging, economic and environmental expected effects were predicted by the improvements of packaging materials and structures to reduce effective packaging waste. Especially expected effects were predicted when improving the structure and material of aluminum laminated material was difficult to recycle. Thus, it was assumed the aseptic carton packaging laminated aluminum were replaced with silica laminated films. In conclusion, analysis of economic expected effects were undervalued in this study because of the limitation of assumptions, though this study has significance about a new approach by calculating the data different from the past that the conventional methods like predictive value of government's guidelines or goals.