• 한국주조공학회지
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• 제23권5호
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• pp.268-275
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• 2003

The mechanism of the hydrogen gas pore formation was investigated in Lost Foam Casting of Al-alloy by reduced pressure test and real casting. The hydrogen gas pick-up was affected by the formed gas during the decomposition of polystyrene in addition to the liquid product. It depended on pouring temperature and a proper temperature of metal front gave the minimum hydrogen pick-up. At a low pouring temperature, the hydrogen went into the melt mainly from entrapped liquid product of polystyrene but pores were formed from the gas as well as the liquid product at a high pouring temperature. The mold flask evacuation down to 710torr decreased the gas porosity down by around 0.4% vol%. The entrapped decomposition product of polystyrene in the melt was observed through the visualization of filling behavior of Al alloy-melt with the high speed camera.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2003년도 추계정기총회 및 국제심포지엄
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• pp.165-169
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• 2003

Current volume reduction methods for wasted expandable polystyrene (EPS) foam are summarized and compared each other. Wasted EPS foam has not been recycled effectively because of its large volume to weight ratio. This has prevented from its proper recycling because of high cost of transportation to recycling plant. Successful recycling of wasted EPS foam results directly from successful, i.e. economically and environmentally, volume reduction of wasted EPS foam. This paper deals with various methods for volume reduction methods of wasted EPS foam. Five typical methods of volume reduction are introduced and they are compared each other in terms of expected PS properties after volume reduction, cost effectiveness of each process, possible effects on environment caused by the volume reduction process, and possible recycled products. The methods include thermal, solvent, far infrared and mechanical compaction. Comparison in this paper is made mostly in qualitative manner. The focus in this study is concentrated on summarizing and comparing existing methods of volume reduction for wasted EPS foam.

• 한국식품영양과학회지
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• 제29권1호
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• pp.76-79
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• 2000

The effects of packaging conditions on freshness extension of squash (Cucurbita moscata) were investigated during 7-day storage at 2$0^{\circ}C$. Weight loss of squash packed with corrugated paperboard box (control) was 5.5%, and those of LDPE (low density polyethylene, Ф0.02 mm), LDPE (Ф0.04mm) film and EPS (expanded polystyrene) box were 0.9%, 0.8%, and 1.1%, respectively. Firmness of EPS was 11% higher than that of control, chlorophill content of squash packed with EPS box was 18.9% higher, and total ascorbic acid content of squash packed with EPS box was 29.4% higher than that of control. Quality of packed squash was not different between EPS packages and LDPE packages. Decay of control was 1~2 pieces per box, but was not found in the LDPE, EPS box. Preferences in overall appearences of LDPE, EPS box was better than those of control.

• 한국안전학회지
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• 제30권1호
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• pp.60-65
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• 2015

This study is to explore floor impact sound and sound insulation of reinforced concrete structure with void-deck slab system which combines polystyrene void foam and T-shaped steel deck plate. A void-deck slab system can effectively reduce the amount of concrete used and hence the mass of a reinforced concrete slab. Also void slab system has dynamically favorable for bending. Three-bay 2-story building was constructed as a mock up test specimen using void-deck slab system and floor impact sound was measured to valuate sound insulation performance. Light weight floor impact and heavy weight floor impact were investigated. Light weight floor impact pressure levels were 32dB, 28dB, and 29db at representative locations which are $1^{st}$ level in the floor impact sound insulation performance grading system. The heavy-weight floor impact pressure levels were 44dB, 45dB, and 43dB at representative locations which are $2^{nd}$ level in the floor impact sound insulation performance grading system. Therefore void-deck slab system can be used in public housing apartment building in terms of not only effectively reduced construction materials but also floor impact sound insulation.

• 폴리머
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• 제32권5호
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• pp.497-500
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• 2008

폴리스틸렌발포체(스티로폼)를 비롯한 소수성 폴리머의 재활용과 친수성 표면개질의 한 방편으로 산소플라즈마 고정화와 그래프팅법을 이용하여 친수성인 아크릴산과 아크릴아미드단량체를 스티로폼 표면에 도입하였다. 플라즈마 처리에 의한 표면개질의 증거는 ESCA스펙트럼의 O/C와 N/C ratio의 증가, 전계방사현미경의 사진으로부터 박막생성 및 접촉각의 현저한 감소 현상의 관찰로부터 확인하였다. 접촉각은 $84^{\circ}$에서 $18{\sim}19^{\circ}$로 대폭 감소하였으며, 이는 아크릴산보다 아크릴아미드가 결정적 요인이 됨을 알 수 있었다.

• 한국포장학회지
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• 제6권1호
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• pp.47-52
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• 2000

개발한 EPS 포장상자가 사과의 신선도 유지효과 기능이 있는지의 여부를 조사코자 사과를 포장하여 $20^{\circ}C$ 저장하면서 골판지상자와 0.02와 0.04mm 두께의 LDPE 필름, 기능성 MA필름과 50배로 발포시킨 EPS상자에 사과를 15kg씩 포장하여 포장재간의 신선도 유지효과를 비교하였다. 저장 40일 후 중량감소는 대조구는 5.7%, EPS 상자는 0.5%의 중량감소가 나타났고, 비타민C도 2.06과 2.31 mg%로 EPS 포장구가 높게 유지되고 있었다. 당도와 산도는 포장구간에 큰 차이가 없었으며 부패의 경우 대조구는 상자당 3-5개과가 발생했으나 EPS포장구는 발생하지 않았으며 외관도 양호한 것으로 나타났다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.763-766
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• 2000

Rapid Prototyping(RP) techniques have their unique characteristics according to the working principles: stair-stepped surface of parts due to layer-by-layer stackin, low build speed caused by line-by-line solidification to build one layer, and additional post processing to improve surface roughness, so it is required very high cost to introduce and to maintain RP apparatus. The objective of this study is to develop software for automatic generation of unit shape part (USP) for a new RP process, Variable Lamination Manufacturing using linear hotwire cutting technique and expandable polystyrene foam sheet as part material (VLM-S). In order to examine the applicability of the developed software to VLM-S, USP's of general three-dimensional shapes, such as an auto-shift lever knob and a pyramid shape were generated.

• 환경사랑
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• 통권49호
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• pp.4-7
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• 2007

일본 발포스티렌 재활용협회(JEPSRA: Japan Expanded Polystyrene Recycling Association)는 금년 4월 EPS제품의 환경부하(LCI) 분석 조사 보고서를 발표했다. TV완충재의 재질에 따른 환경부하와 EPS 단열재 사용으로 인한 에너지.환경부하 절감 효과를 분석한 결과를 요약하여 2회에 걸쳐 소개한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.910-913
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• 2001

Rapid Prototyping(RP) techniques have unique characteristics according to their working principle: the stair-stepped surface of a part due to layer-by-layer stacking, low building speed, and additional post-processing to improve surface roughness. A new RP process, Variable Lamination Manufacturing by using expandable polystyrene foam(VLM-S), has been developed to overcome the unfavorable characteristics. The objective of this study is to investigate the thermal characteristics and skeleton size effects as the hotwire cuts EPS foam sheet in order to improve dimensional accuracy of the parts, which is produced by VLM-S. Empirical and analytical approaches are performed to find the relationship between cutting speed and heat input, and the relationship between maximum available cutting speed and heat input. In addition, empirical approaches are carried out to find the relationship between cutting error and skeleton size, and cutting deviation and skeleton size. Based on these results, the optimal hotwire cutting condition and available minimum skeleton size are derived. The outcomes of this study are reflecting in the enhancement of VLM-S input data generation S/W.

• 한국정밀공학회지
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• 제17권12호
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• pp.185-194
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• 2000

Rapid Prototyping(RP) techniques have their unique characteristics according to the working principles: stair-stepped surface of parts due to layer-by-layer stacking, low build speed caused by line-by-line solidification to build one layer, and additional post processing to improve surface roughness, so it is required very high cost to introduce and to maintain of RP apparatus. The objective of this study is to develop a new RP process, Variable Lamination Manufacturing using linear hotwire cutting technique and expandable polystyrene foam sheet as part material(VLM-S), and to investigate characteristics of part material, cutting characteristics by using linear hotwire cutting system and bonding. Experiments were carried out to investigate mechanical properties of part material such as anisotropy and directional tensile strength. In order to obtain optimal dimensional accuracy, surface roughness, and reduced cutting time, addition experiments were performed to find the relationship between cutting speed and cutting offset of hotwire, and heat generation of hotwire per unit length. So, adhesion strength tests according to ASTM test procedure showed that delamination did not occur at bonded area. Based on the data, a clover-shape was fabricated using unit shape part(USP) it is generated hotwire cutting. The results of present study have been reflected on the enhancement of the VLM-S process and apparatus.