• Polymer(Korea)
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• v.31 no.4
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• pp.289-296
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• 2007

The material factors influencing the sound absorption of the polyurethane foam were investigated with FT-IR, small-angle X-ray scattering (SAXS), and dynamic mechanical thermal analyzer (DMTA). The measurements were performed using the samples which had a similar cell structure but different absorption coefficients. It was found that the ability of the sound absorption of the polyurethane foams was closely related to the damping behavior over the transition range. In order to confirm the use of the low monol polyol (LMP) in high-performance applications, the polyurethanes based on LMP and polypropylene oxide polyol (PPG) were prepared by the solution polymerization method. The microstructure and the physical properties of these polyurethanes were compared. The PPG-based polyurethane showed a higher level of the phase-separated structure because the considerable amount of monol presented in PPG made a contribution to the increased chain mobility. However the short chains formed due to the monol species deteriorated the damping property. As a result, the LMP-based polyurethane showed the superior damping behavior as compared with the PPG-based one.

• Resources Recycling
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• v.15 no.1 s.69
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• pp.28-36
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• 2006

The development of material separation technique for waste plastic recycling are the necessary situation restricted by law the reclamation and incineration of waste plastic after 2004, with enforcement of EPR (Extended Producer Responsibility) system. As the this study is the research on the development of electrostatic separation techniques for recycling of life circles waste plastic by development of charging material and charger, the separation efficiency can be improved. Therefore, we developed the charger and electrostatic separator to increase charging efficiency and material separation per object plastics, rising these equipments, we removed PVC up to $99\%$ from two kinds of mixed plastics. And in case of restricting PVC content such as PET, we developed the separation technique that can remove PVC up to $99.99\%$ from PET with PET recovery about $80\%$. Also, as we separated over $98\%$ for three kinds of mixed plastics, and then established material separation technique to increase recycling of plastic.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.23-33
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• 2005

The development of material separation technique for waste plastic recycling are the necessary situation according to restrict by law the reclamation and incineration of waste plastic after 2004 year, pith enforcement of EPR (Extended Producer Responsibility) system. As the this study is the research on the development of electrostatic separation techniques for recycling of life circles waste plastic, it can improve separation efficiency according to development of charging material and charger. Therefore, we developed the charger and electrostatic separator to increase charging efficiency and material separation per object plastics, using these equipments, we removed PVC up to 99% from two kinds of mixed plastics. And in case of restricting PVC content such as PET, we developed the separation technique that can remove PVC up to 99.99% from PET with PET recovery about 80%. Also, as we separated over 98% for three kinds of mixed plastics, and then established material separation technique to increase recycling of plastic.

• Polymer(Korea)
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• v.35 no.6
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• pp.531-536
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• 2011

Homopolymer distribution in block copolymer/homopolymer blends was investigated as a function of homopolymer concentration and homopolymer molecular weight. The deuterated poly(methyl methacrylate) or polystyrene was blended with a deuterated polystyrene-poly(methyl methacrylate) diblock copolymer up to a concentration of 20 wt%. Samples were characterized by small-angle X-ray scattering (SAXS), neutron reflectivity and transmission electron microscopy. The block copolymer with a thin-film geometry formed alternating lamellar microdomains oriented parallel to the substrate surface. By adding the homopolymer, the microdomain structure was significantly disturbed. As a consequence, a poorly ordered morphology appeared when the homopolymer concentration exceeded 15 wt%. Increasing the homopolymer concentration and/or the homopolymer molecular weight caused the microdomains to swell less uniformly, resulting in segregation of the homopolymer toward the middle of the microdomains.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.247-251
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• 2023

Lecithin can self-assemble into reverse spherical micelles in organic solvents due to its amphiphilic properties. With additives such as D-sorbitol and water, the reverse spherical micelles are transformed into reverse cylindrical micelles by the morphology change of lecithin molecules. In this study, the rheological properties of lecithin/D-sorbitol/water mixtures were investigated. In addition, the small angle X-ray scattering (SAXS) technique was used to examine the shape and size of the formed nanostructures related to their rheological properties. Such mixtures are expected to be used in drug delivery and oleogels because of their high viscosity and viscoelastic behavior.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.970-977
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• 2005

The commercial $V_2O_5-WO_3/TiO_2$ catalysts which had been exposed to the off gas from incinerator for a long time were remanufactured by washing with distilled water and arid solution and reimpregnation with catalytic active components($V_2O_5-WO_3$). The catalytic properties and NOx conversion reactivity of those catalysts were examined by analysis equipment and NOx conversion experiment. Under the experimental condition used in this study, the remanufactured catalysts activated by distilled water ultra sonic cleaning, the catalytic activity was recovered in the range of $66{\sim}93%$ of that of the fresh and the maximum activity was showed when the ultra sonic cleaning time was more than 3 minutes. The remanufactured catalysts by acid solution ultra sonic cleaning, the catalytic activity was recovered in the range of $81{\sim}97%$ of that of the fresh catalyst and the maximum catalytic activity was shooed when the pH of the acid solution was 5. The remanufactured catalysts by reimpregnation with $V_2O_5$ and $WO_3$, the catalytic activity was recovered in the range of $87{\sim}100%$ of that of the fresh catalyst. Maximum catalytic activity was showed when the $V_2O_5$ was reimpregnated more than 1.0 wt %. In this case, the catalytic activity was recovered 97% of that of the fresh catalyst especially at the $150^{\circ}C$ of the experimental temperature.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.317-323
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• 2017

In this study, the heating performance and the energy saving effect of the heat pump system using hot waste water(waste heat) of the thermal power plant discharged from a thermal power plant to the sea were analyzed. The greenhouse area was $5,280m^2$ and scale of the heat pump system was 120 RT(Refrigeration Ton), which was divided into 30 RT, 40 RT and 50 RT. The heat pump system consisted of the roll type heat exchangers, hot waste water transfer pipes, heat pumps(30, 40, 50 RT), a heat storage tank and fan coil units. The roll type heat exchangers was made of PE(Poly Ethylene) pipes in consideration of low cost and durability against corrosion, because hot waste water(sea water) is highly corrosive. And the heating period was 5 months from October to February. During the heating performance test(12 hours), the inlet water temperature of evaporator was changed from $32^{\circ}C$ to $26^{\circ}C$, and heat absorption of he evaporator was changed from 175 kW to 120 kW. The inlet water temperature of the condenser rose linearly from $15^{\circ}C$ to $50^{\circ}C$, and the heat release of condenser was reduced by 40 kW from 200 kW to 160 kW. And the power consumption of the heat pump system increased from 30 kW to 42 kW. When the inlet water temperature of condenser was $15^{\circ}C$, the heating COP(Coefficient Of Performance) was over 7.0. When it was $30^{\circ}C$, it dropped to 5.0, and when it was above $40^{\circ}C$, it decreased to less than 4.0. It was analyzed that the reduction of heating energy cost was 87% when compared to the duty free diesel that the carbon dioxide emission reduction effect was 62% by recycling the waste heat of the thermal power plant as a heat source of the heat pump system.

• Fire Science and Engineering
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• v.34 no.2
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• pp.94-96
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• 2020

In November 2013, a case of sustained combustion of a female body was encountered in a Korean farming village. The body was almost completely incinerated from the neck to the knees, and other parts of the body, such as the head, arms, lower legs, and feet, were slightly damaged. The most likely external ignition source was the flame from a matchstick. The elderly woman was found incinerated on the floor of the living room, while other objects in the house were largely undamaged except for having a brown oily or greasy coating. Flammable substances were not detected from the woman's intact pieces of clothing and socks, and her muscular tissues did not contain toxic chemicals. The concentration of carboxyhemoglobin in her peripheral blood was 11% and that of ethyl alcohol in her aqueous humor was below 0.010%. An autopsy failed to determine the exact cause of death because of excessive charring.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.654-659
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• 2016

Recently, the passenger ship 'Sewol' capsized with an abrupt inclination while she was making a small angle alteration. It is very important to fully understand the concepts, causes and relevant corrections for a ship's transverse inclination, which is classified into heel, list and loll. In this study, the concept, development and calculation of loll were well considered and the actual magnitude of the angle of loll was simulated in a box-shaped model-ship experiment. The experimental values and its development according to different values of negative stability were compared with calculated values. In the results, experimental values for the angle of loll coincided closely with calculated values and the model inclined symmetrically on both port and starboard sides indicating an outstanding feature of loll. This study is expected to expand the concept of loll and help in the analysis of capsize incidents with unknown causes. Further experimental research or case studies concerning the risk of inappropriate correction for loll arising from misunderstandings will be needed.

• Journal of the Korean earth science society
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• v.36 no.1
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• pp.36-50
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• 2015

The purpose of this study is to assign emission source profiles of volatile organic compounds (VOCs) and particulate matters (PMs) for chemical speciation, and to correct the temporal allocation factor and the chemical speciation of source profiles according to the source classification code within the sparse matrix operator kernel emission system (SMOKE) in the Seoul metropolitan area. The chemical speciation from the source profiles of VOCs such as gasoline, diesel vapor, coating, dry cleaning and LPG include 12 and 34 species for the carbon bond IV (CBIV) chemical mechanism and the statewide air pollution research center 99 (SAPRC99) chemical mechanism, respectively. Also, the chemical speciation of PM2.5 such as soil, road dust, gasoline and diesel vehicles, industrial source, municipal incinerator, coal fired, power plant, biomass burning and marine was allocated to 5 species of fine PM, organic carbon, elementary carbon, $NO_3{^-}$, and $SO_4{^2-}$. In addition, temporal profiles for point and line sources were obtained by using the stack telemetry system (TMS) and hourly traffic flows in the Seoul metropolitan area for 2007. In particular, the temporal allocation factor for the ozone modeling at point sources was estimated based on $NO_X$ emission inventories of the stack TMS data.