• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.83-96
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• 2005

PVC is the thermoplastic offering excellent material properties. PVC is used in wide variety of applications, however, it causes environmental problems when it is discarded because of its high chlorine content. Since dechlorination reaction of PVC is taking place relatively low temperature compared to the pyrolysis temperature of plastics, study on the dechlorination reaction has been carried out as a pre-treatment process. Twin screw reactor which shows excellent mixing capabilities is employed. Experimental variables are first and second reactor temperature, PVC content in mixed plastics, viscosity of mixed plastics, feeding rate, rotational speed of the second reactor. Over 90% of dechlorination rate can be obtained under proper operation conditions. Chlorine gas evolved from reactor is absorbed in water and can be recovered as a hydrochloric acid. Analysis had been done on chlorine flows by taking material balance over reactor.

• Journal of Korean Elementary Science Education
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• v.33 no.2
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• pp.401-414
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• 2014

The purpose of this study is to investigate the elementary preservice teachers' conceptions about 'plastics' focusing on non-polar property from a National University of Education. For the study, the views about plastics, relative shapes of a water droplet on plastic or glass material, and relative shapes of water surface in the plastic or glass measuring cylinder were surveyed from the preservice teachers. And the responses were analyzed based on the patterns. The results from the study are as follows: First, most preservice teachers were well aware of the plastic products which are used in daily life. Second, the responses concerning the reason why plastics can be used commonly were divided into 2 categories with 14 sub-level groups. However relatively few preservice teachers mentioned regarding 'chemical stability' and 'conductivity', which are associated with the plastics' non-polar property. Third, it was found that 50 participants (30.1%) had 'Scientific conception (Sc)', 38 (22.9%) had 'Partial-scientific conception (Ps)', 66 (39.8%) had 'Misconception (Mc)', and 12 (7.2%) had 'No conception (Nc)' on the subject of the relative shapes of a water droplet. Fourth, the distribution patterns and the ratio of the preservice teachers' conception on the survey question 3 concerning the relative shapes of water surface were quite similar to those of the survey question 2. So it was concluded that overall understanding level of the preservice teachers was pretty low on the subjects of the relative polarities of the plastic, glass, and water as well as their interactions. Fifth, the distribution percentile of 'Sc'/'Ps'/'Mc'/'Nc' was not related with the gender but highly correlated with preservice teachers' academic field and their science subjects taken in high school. Based on the results from the study, some educational guidelines were suggested.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.540-544
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• 2008

Pyrolytic characteristics of mixed plastics containing 22 wt.% HDPE, 17 wt.% LDPE, 27 wt.% PP, 12 wt.% PS, 16 wt.% ABS, 6 wt.% PVC have been studied in the batch-type microreactor of stainless steel. Thermal degradation experiments were performed at temperature of $410{\sim}450^{\circ}C$. The yield of each pyrolytic products were obtained by the weight measurement and molecular weight distribution of pyrolytic liquid products determined by the GC-SIMDIS method. It was shown that the yield and molecular weight of pyrolytic liquid product were decreased with the increase of reaction temperature and time. It was know that 20wt% of PVC composing of the mixed plastics was converted to the gas products of chloride during the pyrolysis process. The chain-end scission rate parameter was determined to be 50.2 kcal/mole of mixed plastics by the Arrhenius plot.

• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.453-460
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• 2009

In order to provide fundamental data for developing high-grade(high-quality and low-pollution) Refuse Derived Fuel(RDF), we analyzed caloric value and HCl content by Municipal Solid Waste(MSW) type. The caloric value was analyzed using calorimeter and HCl content was analyzed using mercury(II) thiocyanate method. In case of paper type the caloric value was 3,060~3,608kcal/kg and the HCl content was 239~6,135ppm. In case of vinyl-plastics the caloric value was 5,946~9,888kcal/kg and the HCl content was 429~455,771ppm. According to the result of quality assessment by MSW type, the calroric value of vinyl-plastics type was showed higher than that of paper type and in case of HCl content the paper type was showed lower than vinyl-plastics type. So, We mixed paper and plastic wastes. The caloric value of mixed MSW(paper and plastics) was 5,046~9,125kcal/kg and the HCl content was 239~6,135ppm. Also, The caloric value of packaging waste(film-plastics) was 5,982~8,045kcal/kg. Therefore It is possible to develop high-grade Refuse Derived Fuel through suitable mixing of paper and plastic in municipal solid waste.

• KSBB Journal
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• v.16 no.2
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• pp.123-127
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• 2001

For testing antimicrobial activity of functional plastics containing antimicrobial agent. We have used Escherichia. coli (ATCC 25922) and Staphylococcus. aureus (ATCC 6538P) with plastics which contained a Ag-hydroxyl apatite agent. In this paper, effect of antimicrobial test on plastics containing silver complex agent which accomplished by using test condition that Trypticase Soy Broth (TSB solution have diluted 500 times with 0.1 M phosphate buffer), pH7.2, Temp. $37\pm1^{circ}C$ and 120 rpm for 24 hr. the condition give the opportunity to better perform the antimicrobial active effect of individual functional plastics. As result. the test conditions were best effect of antimicrobial by using plastic contained minimum 0.5% with Ag-hydroxyl apatite agent.

• Resources Recycling
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• v.9 no.6
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• pp.23-30
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• 2000

Since most of the waste plastics are incinerated and landfilled for the plastic treatment, the environmental friendly processes must be introduced. The plastic utilization of plastic to the blast furnace as a substitutional fuel was developed as a useful recycling method of waste plastics, and commercialized in several ironmaking company in Europe and Japan. Present study was carried out to understand the effect of plastic injection on blast furnace process continuously by using the foundry blast furnace in POSCO. The coke replacement ratio turned out to be 0.98 with the waste plastic injection up to 13.8 kg/thm of injection rate, and there were no significant effect of the kinds of injection plastics on the replacement ratio in this test operation. The permeability in the furnace became worse and the heat load in the lower part of blast furnace was increased with increasing the injection rate of waste plastics. As the rate of plastic injection were increased, the top gas utilization and shaft efficiency were also decreased from the Rist diagram analysis.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.154-159
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• 2004

In this study, in order to perform more efficiently reliability design and integrity assessment of structural members, the relational database management program on the engineering plastics was constructed. This program contained 476 grades for 14 kinds of the engineering plastics and was developed using MS-access and MS-visualbasic. This program consists of 3 modules; search condition, probabilistic characteristics of material property, evaluation of P-S-N curve. We perform fatigue test for probabilistic durability analysis and this results input the database program to estimate P-S-N.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.2
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• pp.106-111
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• 2007

In this research work attempts were made to study the bonding of thermo-plastics with adhesives using solar radiation. In order to study the curing behaviour necessary experiments were conducted under varying conditions of temperature, exposure time and power of solar energy. The cured samples were then studied under the optical microscope before subjecting to tensile testing in order to study their mechanical properties of thermo-plastics. The fracture surfaces were further studied under the Scanning Electron Microscopy(SEM) in order to research the microstructural changes that are taken place during curing. In order to measure the performance of solar energy cured joints the parameters such as; bond strength, surface morphology, the microstructual changes, variation in properties of adhesives bonded joints are compared to that of specimen cured at ambient conditions and specimen cured using microwave techniques.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.10 no.1
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• pp.37-46
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• 2004

The aim of this study was to develop the recycling methode of alloyed recycling plastics. The compatibilizers have been used to improve the physical properties of recycling plastics. Eethylene propylene rubber(EPR), ethylene propylene diene monomer(EPDM), styrene ethylene butylene styrene block copolymer(SEBS), maleic anhydride modified styrene ethylene butylene styrene block copolymer(SEBS-MA) and styrene butadiene styrene block copolymer(SBS) were singled out as compatibilizers. In this study, the physical properties such as impact and tensile strength have improved above 20% by using the compatibilizers.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3175-3184
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• 1994

The high strength and wear-resistant metal bonded diamond wheel was applied to the drilling process of carbon fiber reinforced plastics (CFRP), The helical-feed drilling method was use for the first time to overcome the limit of drilling depth of the conventional drilling process and to improve the dressing of the wheel. The helical-feed drilling method was found effective at high cutting speed without the limit of drilling depth.