• Journal of Environmental Science International
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• v.11 no.4
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• pp.327-332
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• 2002

Optical microscope, SEM (Scanning Electron Microscopy) and fluorescent microscope were used for qualitative and morphological studies of the attached biomass on PE (polyethylene) substratum under anaerobic condition. It was shown by the observation of optical microscope that the initial attachment of biomass began in crevices of the surface of PE. The shape and structure of the attached biofilm could be observed by SEM photographs, but species of bacteria were and methanogens were not classified. A large number of methanogenic bacteria were identified on the surface of PE substratum by fluorescence under 480nm of radiation. It was estimated that methanogenic bacteria was also related to initial attachment of biomass under anaerobic condition.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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• pp.73-81
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• 1997

This study was to find the best adhesive condition comparing mechanical property in case of hot-melt adhesion using glue-gun, ultrasonic welding with adhesion and only ultrasonic welding in order to adhere thermoplastic resin of polyethylene (PE) in which reliable adhesion was resulted in case of ultrasonic welding with same materials of PE. The best welding condition were acquired at welding time 1 second, welding pressure 250kPa for PE-PE where welding time and welding pressure were increased in accordance with the increase of material strength. At the best ultrasonic welding conditions, bonding strength of PE-PE welding was about 21MPa of which material have tensile strength of 24MPa. Through the analysis of microscophic test for ultrasonic welding structure, it was distinguished between well welded structure with higher intermolecule flow and bad welded structure with lower flow, of which result is mostly correspond with the result of tensile strength test.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.228-233
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• 2001

This study was carried out to characterize the enzymatic properties and effectiveness on the firmness of pectinesterase(PE) and polygalacturonase(PG) which are present in carrot cell wall, and to determine the blanching condition of raw carrot. Crude enzyme was extracted from carrots and used as PE and PG. The optimum pH of PE and PG activity were 7.0 and 5.0, respectively. NaCl enhanced PE and PG activities, particularly at 0.15 M and 0.10 M, respectively. Although the optimum temperature of PG ($70^{\circ}C$) was higher than that of PE ($50^{\circ}C$), PE ($Z-value=8.76^{\circ}C$) was more heat-stable than PG($Z-value=6.67^{\circ}C$). Blanching condition was determined as at $55^{\circ}C$ for 60 min in 0.03 M $CaCl_2$, 0.1 M NaCl and pH 7.0 from measuring firmness after blanching at various temperature ($50~70^{\circ}C$) and time (5~60 min).

• Journal of the Korean Institute of Gas
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• v.11 no.3
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• pp.49-55
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• 2007

Polyethylene pipes have been widely used as they are easy to construct and suitable for economical efficient when they are compared with metal pipelines. This paper studies the effect of various external loadings on stress and deflection of the buried PE pipes using Finite Element Method(FEM). For this purpose, stresses of buried PE pipes are calculated according to the loading condition such as pipe types (pipe diameter $50{\sim}400mm$), burial depths ($0.6{\sim}1.2m$) and internal pressures ($0.4{\sim}4bar$). As a result, it is founded the effect and relation with each of loading conditions under the buried condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.154-155
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• 2006

This paper describes a tracking test results for the organic polymers with PE(polyethylene) series by a declining method. After processing the 4 PE series insulations with different density, the tracking duration for each was measured and compared with that for ABS(acrylonitrile butadiene styrene). The surface condition of each specimen was carefully observed after the tracking test. As a result, HDPE showed excellent performance in tracking test.

• Resources Recycling
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• v.11 no.1
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• pp.37-42
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• 2002

This study was conducted in order to remove Poly vinyl chloride(PVC) from the waste plastic film mixture. The fittings of Air Table was modified to increase the separation efficiency of PVC and PE(poly ethylene). PE and PVC was successfully separated from PVC-PE film mixture with the yield of PE 90% or more and with his grade of 99% or more, using the improved Air Table. The details of the separation condition and results will be discussed in this paper. Dry separation, Waste plastic film, PVC, Air Table. The details of the separation condition and results will be discussed in this paper.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.359-365
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• 2021

We investigated experimentally the ignition characteristic of dust and the hazard evaluating for electrostatic discharge. The ignition energy experiments were performed on sample dusts such as PE(HD), PE(LD), PMMA using the MIKE-3 apparatus. The formation of flame during the ignition of PE(HD) dust clouds occurred after the delay time of about 8 ms, and the flame kernels were not observed in center of ignition occurrence area. The voltage increased with increasing the number of dust dispersions and the increase rate of measured voltage with dust concentration was the highest in the order of PMMA, PE(LD) and PE(HD). For the effect of dispersion condition on the voltage in PE(HD) dust, the results were obtained that the voltage increased as the number of dispersions increased and as the concentration increased under the same dispersion number. The safety voltages to prevent fire and explosions by electrostatic ignition were estimated that PE(HD), PE(LD)-1, PE(LD)-2, and PMMA were 2.58, 44.72, 25.82, and 8.16 kV, respectively. We proposed the method for estimating the minimum ignition energy by using the measured voltage data for efficient investigation of electrostatic ignition hazard.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.209-210
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• 2011

This study is aimed to draw a optimum combined fiber mix condition to improve spalling resistance and flowability of ultra high-strength concrete. As a result, W/B 12.5% concrete specimens were prevented spalling with PE0.05+ PP0.1, PE0.05+NY0.1 and W/B 12.5% concrete specimens were prevented spalling with all of combined organic fiber mix condition. But There is no significant influence of steel fiber under 5% volume ratios to prevent spalling. In the scope of this study, we suggest that condition of optimum volume ratio PE0.05+NY0.1 is to improve spalling resistance, flowability and residual compressive strength.

• Journal of the Korean Society of Safety
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• v.17 no.2
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• pp.16-21
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• 2002

At present the Polyethylene piping, on supporting LNG is widely used because of it's disposition which are anti-corrosion flexible and so on. However, it has a few kinds of risk which are the possibility of piping leak, the character of easily corroded and so on. For giving solution, this study is intended to experiment the intension of the PE pipe after melted and when it is melting, the condition which are temperature and pressure is changed. the melting condition in temperature and pressure is adapted identically. After melting, it's joint is tested as intension. The result is that the effect of temperature in intension is more effective than pressure. In $210^{\circ}C$, $20kg/cm^{2}$ condition, the melting intension has the highest. Compare to the Butt melting joint and the Saddle melting joint, the former was $214kg/cm^{2}$ and the latter was $50kg/cm^{2}(bead\;2{\sim}3mm)$ and $73kg/cm^{2}(bead\;5{\sim}7mm)$. It means that the Butt melting method has more intensive than saddle. Consequently, the result shows that the liability and safety when pipe melting method is used will improve in pipe installation.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.463-469
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• 2018

A currently used roof green system with multi layers has a low constructability. Therefore a new integrated waterproof & root barrier sheet and roof green box unit system was developed using steel plate fixture and cone type fixture by electromagnetic induction heating method. This study was proceeded to evaluate adhesion performance of two types of fixtures on Engineering PE, TPO, PVC sheet in a normal condition, repeated heating and cooling condition. As a result, adhesion load on Engineering PE sheet showed the highest value. The adhesion loads of steel plate fixture showed higher value as heating temperature was getting higher. However adhesion loads of cone type fixture showed opposite tendency. Regarding to the test conditions, test results of normal condition, repeated heating and cooling condition showed same value. The cone type fixture using butyl tape showed 7 times lower adhesion load than that of cone type fixture using electromagnetic heating and 28% lower adhesion load in a repeated heating and cooling condition than a usual condition.