• 한국포장학회지
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• 제27권3호
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• pp.175-180
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• 2021

Although it has recently been regulated for use as an eco-friendly policy in Korea, the use of EPS (Expanded Polystyrene) cooling boxes, which are used as cold chain delivery insulation boxes for fresh agricultural and livestock products, is also increasing rapidly as e-commerce logistics such as delivery have increased rapidly due to COVID-19. Studies were conducted to optimize the EPS cooling container through internal air heat flow of CFD (Computational Fluid Dynamics) analysis and FEM (Finite Element Method) random vibration analysis using domestic PSD (Power Spectral Density) profile of the EPS cooling box to which the refrigerant is applied in this study. In the analysis of the internal air heat flow by the refrigerant in the EPS cooling box, the application of vertical protrusions inside was excellent in volume heat flow and internal air temperature distribution. In addition, as a result of random vibration analysis, the internal vertical protrusion gives the rigid effect of the cooling box, so that displacement and stress generation due to vibration during transport are smaller than that of a general cooling container without protrusion. By utilizing the resonance point (frequency) of the EPS cooling box derived by the Model analysis of ANSYS Software, it can be applied to the insulation and cushion packaging design of the EPS product line, which is widely used as insulation and cushion materials.

• 한국결정성장학회지
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• 제29권3호
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• pp.132-139
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• 2019

EPS 단열재는 우수한 단열성능과 경제성, 초경량 등의 장점으로 각광받고 있는 건축재이다. 하지만 EPS 단열재는 가연성 물질로서 화재 시 연소되기 쉽고, 유해가스를 방출시킴으로써 대규모 인명피해를 유발 시킬 수 있다. 따라서 본 논문에서는 산업부산물인 IGCC fused slag 및 Si sludge를 활용하여 초경량 지오폴리머를 제작하고, EPS 단열재의 대체 가능성에 대해 확인하고자 하였다. 그 결과, 조분쇄 상태의 탄소 함량이 적은 IGCC fused slag를 이용하였을 경우 0.04 MPa, $0.064g/cm^3$의 압축강도 및 밀도를 갖는 초경량 지오폴리머를 제작할 수 있었고, 이때의 열전도율은 0.072 W/mK을 나타내었다. 이는 KS M 3808에서 제시하는 EPS 열전도율 값의 1.5~2배 정도의 높은 물성이지만 시중에서 판매하는 EPS 단열재와 큰 차이가 없으며 보통 매립되는 산업 부산물을 재활용한다는 점과 세라믹 재료 특성상 화재시에도 고온에서 버틸 수 있다는 큰 장점이 있기 때문에 화재시 쉽게 발화되어 다량의 유독가스를 방출시키는 EPS 단열재의 단점을 해결할 수 있는 차세대 단열재로서의 가능성은 충분하다고 판단되었다.

• 한국지반신소재학회논문집
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• 제2권2호
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• pp.3-11
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• 2003

지중매설구조물에 작용하는 수직하중 저감기법인 유도 고랑형 기법은 관거 상단의 내부토체에 압축성이 큰 재료(점토, 이토, 지푸라기 등)를 뒤채움함으로서 다짐된 지반인 외부토체에 대해 상대적으로 하향 침하하는 변위를 유발시킴으로써 발생되는 아칭효과에 의해 하중을 저감시키는 기법이다. 그러나, 기존의 유도 고랑형 기법은 상대적 변위를 유발시키기 위한 압축재인 점토, 이토, 지푸라기 등이 현장의 품질관리차원에서 관리가 어렵다는 문제점을 가지고 있다. 최근의 관련 연구 경향은 압축재로서 재료 관리가 용이한 대체 재료의 개발과 EPS 블록의 활용성 검증 등에 초점이 모아 지고 있는 실정이다. 본 논문에서는 연성강관의 포설 효과, EPS 블록 포설 형태, 연성강관의 직경 등을 변화인자로 한 일련의 실험을 통하여 연성관 및 EPS 블록 포설에 따른 수직하중 저감 효과와 매커니즘을 분석하고, 현장적용에 필요한 최적 단면 및 설계 시 적용되는 환산하중계수(K')을 제시하고자 한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.553-562
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• 2008

A remediation technique for buried pipeline system subject to permanent ground deformation is proposed. Specifically, EPS (expanded polystyrene) geofoam blocks are used as low density backfill, thereby reducing soil restraint and pipeline strains. In order to evaluate this remediation technique, a series of 12 centrifuge model tests with HDPE pipe were performed. The amount or spatial extent of the low density backfill was varied, as well as the orientation of the pipe with respect to the fault offset. Specifically, in the $-63.5^{\circ}$ test, the orientation was such that the pipe was placed in flexure and axial tension. The $-85^{\circ}$ orientation placed the pipe mainly in flexure. In all cases, the behavior of the remediated pipe was compared to that for the unremediated pipe. The geofoam backfill was successful in improving pipe behavior for two of the three pipe/fault orientations. However, for the $60^{\circ}$ orientation, the pipe buckled in compression irrespective of the geofoam backfill.

• Steel and Composite Structures
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• 제34권4호
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• pp.581-597
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• 2020

Light-Weight Concrete containing Expanded Poly-Styrene Beads (EPS-LWC) is an approved structural and non-structural material characterized by a considerably lower density and higher structural efficiency, compared to concrete containing ordinary aggregates. The experimental campaign carried out in this project provides new information on the mechanical properties of structural EPS-LWC, with reference to the strength and tension (by splitting and in bending), the modulus of elasticity, the stress-strain curve in unconfined compression, the absorbed energy under compression and reinforcement-concrete bond. The properties measured at seven ages since casting, from 3 days to 91 days, in order to investigate their in-time evolution. Mathematical relationships are formulated as well, between the previous properties and time, since casting. The dependence of the compressive strength on the other mechanical properties of EPS-LWC is also described through an empirical relationship, which is shown to fit satisfactorily the experimental results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.833-836
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• 2006

The purpose of study is to develope for lightweight concrete panel which have high quality with insulation performance of sound. The use of lightweight concrete products has been increased at a recently high structures. Also, the gathering of nature aggregate is limited, so that lack of fine aggregate is appearing. Statistical analysis is practiced on the properties of EPS concrete according to the variation of mix design. As a result saturated density is affected by amount of Bottom ash.Also compressive strength is affected by W/B ratio at the early age and amount of Bottom ash at the latter age.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.379-380
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• 2017

고압 DC 입력을 갖는 SMPS에서 넓은 입력전압 영역에서 동작하기 위해서는 기존 플라이백 방식으로는 그 한계가 있다. 따라서 넓은 입력전압 영역에서 동작하기 위해서는 2단방식의 SMPS의 적용이 고려될 수 있다. 2단 방식 SMPS를 적용할 경우 각 단 중 1단에만 전압제어를 행하고 나머지 1단은 단순히 DC/DC 트랜스포머 역할을 하게 되면 효율증대를 꾀할 수 있다. 본 논문에서는 전압제어용 DC/DC 컨버터와 DC/DC 트랜스포머용 DC/DC 컨버터를 결합한 SMPS를 제안하고 그 타당성을 검증하였다.

• 한국산업융합학회 논문집
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• 제23권1호
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• pp.83-91
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• 2020

The evaluation of the compression behavior of the cushioning material is of importance to achieve appropriate packaging design. In order to change packaging design from polymeric-based to more eco-friendly cellulose-based nire effectively, comparative study on the compression behavior between these two packaging materials is crucial. In this study, the stress-strain behavior, hysteresis loss, and response characteristics for cyclic loading were analyzed through compression tests on multi-layered corrugated structure (MLCS) and expanded polystyrene (EPS) packaging materials. MLCS produced in Korea is produced by winding a certain number of single-faced corrugated paperboard, and the compression behavior of this material was turned out to be 6 stages: elastic stage, first buckling stage, sub-buckling stage, densification stage, last buckling stage and high densification stage. On the other hand, EPS's compression behavior was in 3 stages: linear elastic stage, collapse plateau, and densification stage. The strain energy per unit volume (strain energy density) of MLCS did not differ depending on the material thickness, but it showed a clear difference depending on the raw material and flute type. Hysteresis loss of MLCS ranged from 0.90 to 0.93, and there were no significant differences in the raw material and flute type. These values were about 5 to 20% greater than the hysteresis of the EPS (about 0.78 to 0.87).

• 한국도로학회논문집
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• 제10권1호
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• pp.87-95
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• 2008

형상이 일정하지 않은 구조에 충돌하는 차량의 탑승자 안전을 확보하기 위해서 그 구조물의 앞에 공간이 허용하는 한도의 깊이만큼 충격을 흡수하는 재료로 만든 모듈을 쌓아두는 방법을 생각할 수 있다. 충격흡수모듈로 사용되기 위해서는 재료가 충분한 에너지 흡수능력을 가져야 하고 동시에 탑승자의 안전을 확보할 수 있어야 한다. 본 논문에서는 에너지 흡수능력과 더불어 탑승자의 안전을 보장하기 위하여 충격흡수재료가 가져야 할 조건을 설명하고 auard-Guard 시스템 모듈, 샌드백, 재활용 타이어, 지오컨테이너, 지오셀 그리고 EPS 블록에 대한 정적압축실험을 실시하여 그 결과를 분석하였다. 이로부터 $30kg/m^{3}$의 밀도를 갖는 EPS 블록이 쿠션모듈로 사용되기 적합한 재료임을 보였다. 한편 시속 35.6km/h까지의 충돌조건으로 Drop Test를 실시하여 EPS블록의 정적특성과 동적특성간 큰 차이가 없음을 보여 주었으며 쿠션모듈로서의 성질을 개선시키기 위한 방안으로 EPS 블록에 공극을 두는 방안을 제안하고 공극이 있는 EPS블록에 대하여 Drop Test를 실시하여 EPS 블록을 이용한 충격흡수시설의 설계에 필요한 재료적 특성치를 제시하였다.

• Computers and Concrete
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• 제29권2호
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• pp.107-115
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• 2022

With the improvements in computer technologies, utilization of image processing techniques has increased in many areas (such as medicine, defence industry, other industries etc.) Many different image processing techniques are used for surface analysis, detection of manufacturing defects, and determination of physical and mechanical characteristics of composite materials. In this study, cementitious composites were obtained by addition of Grounded Granulated Blast-Furnace Slag (GGBFS), Styrene Butadiene polymer (SBR), and Grounded Granulated Blast-Furnace Slag and Styrene Butadiene polymer together (GGBFS+SBR). Expanded Polystyrene (EPS) beads were added to these cementitious composites in different ratios (20%, 40% and 60%). The mechanical and physical characteristics of the composites were determined, and homogeneity indexes of the composites were determined by image processing techniques to determine EPS distribution forms in them. Physical and mechanical characteristics of the produced samples were obtained by applying consistency, density, water absorption, compressive strength (7 and 28 days), flexural strength (7 and 28 days) and tensile splitting strength (7 and 28 days) tests on them. Also, visual examination by using digital microscope, and image analysis by using image processing techniques with open source coded ImageJ program were performed. As a result of the study, it is determined that GGBFS and SBR addition strengthens the adhesion sites formed as it increases the adhesion power of the mixture and helps to get rid of the segregation problem caused by EPS. As a result of the image processing analysis it is demonstrated that GGBFS and SBR addition has positive contribution on homogeneity index.