• Proceedings of the Korean Society of Rheology Conference
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• 2002.05a
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• pp.149-152
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• 2002

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.907-914
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• 2012

Flexible pipes take advantage of their ability to move, or deflect, under loads without structural damage. Common types of flexible pipes are manufactured from polyethylene (PE), polyvinyl chloride (PVC), steel, glass fiber reinforced thermosetting polymer plastic (GFRP), and aluminum. In this paper, we present the result of an investigation pertaining to the short-term behavior of buried polyethylene pipe. The mechanical properties of the polyethylene pipe produced in the domestic manufacturer are determined and the results are reported in this paper. In addition, vertical ring deflection is measured by the laboratory model test and the finite element analysis (FEA) is also conducted to simulate the short-term behavior of polyethylene pipe buried underground. Based on results from soil-pipe interaction finite element analyses of polyethylene pipe is used to predict the vertical ring deflection and maximum bending strain of polyethylene pipe.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.561-566
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• 2017

Butt-fusion welding process is used to join the polymeric pipes. Recently, some researchers suggest the curved surface to enhance a welding quality. We investigated how curved welding surface affects heat and flow behaviors of polymer melt during the process in 2D axisymmetric domain with finite element method, and discussed the effect to the welding quality. In this study, we considered HDPE pipes. In heat soak stage, curved phase interface between the melt and solid is shown along the shape of welding surface. In jointing stage, squeezing flow is generated between curved welding surface and phase interface. The low shear rate in fusion domain reduces the alignment of polymer to the perpendicular direction of pipes, and then this phenomenon is expected to help to enhance the welding quality.

• Geotechnical Engineering
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• v.14 no.5
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• pp.89-110
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• 1998

Variations of backfill load on the metal-polyethylene composite( MPC ) pipes buried in various trenches backfill afterward were investigated in this paper. The backfill loads obtained by the finite element method( FBM ) were compared with those calculated by the well-known MarstonBpangler(M-5) theory. The reliability of the finite element analysis used in this study was examined by an inaitu best for the buried pipe. The backfill lords and deflections on the real-size pipe buried on-site were measured while increasing the backfill height. In addition, further investigations were made for the variations of the backfill loads as a function of several important parameters such as the backfill soil type, bach. height$(\leq4.0m)$, diameter of the pipe$(B.$1.0m)$, and trench width($\leq 3.0 B_c$). It is confirmed that the M-S theory predicts reasonably well the backfill loafs of the MPC of the M-S backfill coils be 0.13 and 0.15 for the SC and SM coils in the D unman soil model, respectively. The load ratio, Wu-s/WwgM for a narrow trench varies negligibly with the back(111 height but fiends to increase for a wide trench. The ratio increases with increasing diameter of the pipe for a narrow trench while decreasing for a wide trench. It is also found that the ratio generally decreases as the degree of compaction increases and BM soil exhibits larger load ratio than that of SC soil.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.281-286
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• 2001

우리나라는 석유가 나지 않는 비산유국으로서 거의 모든 에너지 자원을 막대한 외화를 지급하여 수입하고 있는 실정이다. 이렇게 수입되는 에너지원중에서 대기 오염 등의 환경문제가 대두되면서 액화 천연가스가 청정에너지로 두각을 나타내게 되었으며, 국내에서는 도시가스로 보급되어 수요가 점차적으로 계속 증가하고 있는 추세이다 기체상태로 기화된 천연가스는 일반 가정이나 산업체에 관로(pipe line)를 통하여 공급되는데, 이들 가스배관은 대부분 지하에 일정한 깊이로 매몰되어 설치된다.(중략)

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.98-104
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• 1986

Fish jelly forming ability of freeze-dried roundnose flounder meat paste has been examined . For the qualify test, freeze-dried product was packed in polyethylene bag (0.1 mm thick, $14\;cm\;{\times}\;20\;cm$) or in tinplate can and stored for 6 months at $5^{\circ}C,\;20^{\circ}C\;and\;35 ^{\circ}C$. From the results of quality test, the fish jelly forming ability of the products packed in polyethylene bag and can were maintained for 5 and 6 months storage at $5^{\circ}C$ and for 3 and 4 months at $20^{\circ}C$. espectively, while it had already been lost for 1 month at $35^{\circ}C$. Freeze-dried roundnose flounder meat paste can be used for preparing fish jelly products.

• Fire Science and Engineering
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• v.16 no.4
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• pp.77-84
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• 2002

In this paper, we had analyzed comsbustion gases using a GASTEC colorimetric gas detector tube according to the method of NES 713 in order to combustion gases toxicity evaluation for beads polystyrene foam, extruded polystyrene foam, rigid polyurethane foam, flexible polyurethane foam, flexible polyvinyl chloride pipe, vinyl floor cover, polyethyelene foam(flame retardant untreated) and polyethyelene foam (flame retardant treated) of plastics material. As results of gas analyses by using this method, comsbustion gases producted from small specimens of plastics material had reached fatal to man at 30 minutes exposure time that had possesed toxicity index of more than 1. Toxicity indexes of each specimen were estimated range of 4.3∼179.2, flexible polyvinyl chloride showed the hightest toxicity index at 179.2, and beads polystyrene foams showed the lowest toxicity index at 4.3.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.7-12
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• 2017

Most of existing buried pipes are composed of reinforced concrete. Reinforced concrete pipes have many problems such as aging, corrosion, leaking, etc. The polyethylene (PE) pipes have advantages to solve these problems. The plastic pipes buried underground are classified into a flexible pipe. National standard that has limited the long-term vertical deformation of the pipe to 5% for flexible pipes including PE pipe. This study presents a prediction for the long-term behavior of the polyethylene pipe based on ASTM D 5365. This prediction method is presented to estimate by using the statistical method from the initial deflection measurement data. We predict the behavior of long-term performance on the double-wall pipe and multi-wall pipe. As a result, it was found that the PE pipe will be sound enough more than 50 years if the compaction of soil around the pipe is more than 95% of the standard soil compaction density.

• Polymer(Korea)
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• v.25 no.6
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• pp.848-854
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• 2001

The crystallization behavior of poly (ethylene terephthalate) (PET) /ethylene-methyl acrylate-glycidyl methacrylate copolymer (E-MeA-GMA) blend was studied. The extent of reaction and the reaction rate between PET and E-MeA-GMA were measured with torque rheometer, FT-IR and SEM. The effects of the grafting reaction on the crystallization behavior were investigated with DSC and time-resolved light scattering (TR-LS) techniques. The morphological change at the lamellar level was also examined by using a small angle X-ray scattering (SAXS) method.

• The Korean Journal of Rheology
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• v.2 no.1
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• pp.67-78
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• 1990

세라믹 분말의 사출성형성을 평가하기 위하여 다양한 혼합체 시스템에 대한 혼합도 와 유변학적 성질을 질화규소 미세분말의 부피비를 변화시키면서 조사하였다. 열가소성 결 합체 시스템은 폴리에틸린 폴리에틸렌 왁스 그리고 미소량의 첨가제를 혼합하여 사용하였 다. 혼합성능을 평가하기 위하여 비분산혼합에서는 총접촉면적비를 그리고 분산혼합에서는 총파괴표면적비를 혼합척도로서 사용하여 정성적으로 모형화하였다. 사용된 혼합기내의 유 동장을 해석하기 위하여 뉴우톤유체를 가정하여 유동해석을 수행하였다. 혼합물의 혼합도는 각각 5분 30분 동안 혼합된 시편을 주사전자현미경 사진에 의해 관찰하여 평가하였다. 또한 혼합물의 사출성형성 그리고 혼합질 점도 토우크 곡선 사이의 관계를 규명하기 위하여 전단 변형를 속도를 따른 점도를 모세관 점도계를 사용하여 측정하였으며 질화규소의 부피비가 60%일 때까지는 만족할 만한 성형성과 혼합질을 가짐을 알 수 있었다.