• International Journal of Air-Conditioning and Refrigeration
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• v.15 no.2
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• pp.78-83
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• 2007

An experimental study has been carried out to analyze the thermal stability and to estimate the lifetime of refrigerating lubricants. PAG and POE oil are considered as test oils in this study. The viscosity of PAG and POE oil was measured by the vibration type viscometer while temperature is varied periodically in the range of $0^{\circ}C{\sim}100^{\circ}C$. In order to estimate lifetime of PAG and POE oil with temperature, the viscosity was measured while the test temperature of oils was maintained continuously at $180,\;200\;and\;220^{\circ}C$. The lifetime of oils is estimated as the decrease in viscosity change by 15%. The results indicate that the reduction rates of viscosity of PAG and POE oil are less than 5% after 510 temperature variation cycles. However, when the oils are kept at high temperature, it is found that the lifetimes of PAG oil is seen to be 244, 177 and 89 hours at the test temperature of $180,\;200\;and\;220^{\circ}C$, respectively, where as the lifetimes of POE oil are estimated to be 1,744, 1,007 and 334 hours at the temperature of $180,\;200\;and\;220^{\circ}C$, respectively. Thus, the lifetime of POE oil is found to be much longer than that of PAG oil. The lifetime correlations of PAG and POE oil are also obtained by Arrhenius's equation method in this paper.

• Journal of the Korean Institute of Rural Architecture
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• v.9 no.1
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• pp.9-16
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• 2007

Educational Facility has a specialty that similar design is repeatedly taken place so the importance of POE(Post Occupancy Evaluation) is increased for the improvement of problem appeared at the former projects. The POE could provides help to the design of next project and the direction when the need of remodeling is faced. Through the process of POE, the repeat of design mistakes could be prevented and the good information related with building efficiency and other problems could be applied to the design of next school project . In this study, the POE of Manbalro(barefoot) toilet of D Elementary school in rural area of H county is performed. The toilet is renovated as an educational environment improvement project of H county educational office in Chungcheong Namdo Province. The study is focused on the user's behavior at Manbalro toilet for carrying out indicative POE by the subjective response of user's. From the research, several being reformed items is proposed however the toilet is evaluated as a successful project that design purpose of initial stage is applied well.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.87-89
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• 1999

본 연구에서는 Sorfactant/Cosolvent 혼합용액을 적용한 Soil flushing 기법에 의해 농약(Endosulfan(6,7,8,9,10,10-Hexachlor-1,5,5a,6,9,9a-hexahydro-6,9-methane-2,3,4benzo (e)dioxathiepin-3-oxide))으로 오염된 토양의 정화효율을 알아보았으며, 회분식 및 연속식 실험을 통하여 최적의 운전조건을 도출하고자 하였다. 세척용액의 적정 사용조건을 알아보기 위한 회분식 실험은 Jar tester를 사용하여 진탕비 (토양 중량 : 세척용액 부피), Surfactant(SDS ＋ POE$_{5}$, POE$_{9}$ ＋ POE$_{14}$, POE$_{5}$ ＋ POE$_{14}$, POE$_{14}$)와 보조용매(water, ethanol, methanol, ethanol＋methanol)의 혼합비 및 농도 조건을 변화시켜가며 토양세척을 수행하였다. 세척용액은 보조용매에 Surfactant의 농도를 0.5%, 1%로 용해하여 적용하였다. 연속식 실험은 회분식 실험에서 얻어진 최적 세척용액 사용조건 즉, 계면활성제 SDS + POE$_{5}$(1:1, 용액농도 1%), 보조용매 ethanol을 일정 비율로 혼합한 세척용액을 오염된 토양이 충진된 유리칼럼에 여러 유량조건에서 1 - 20 pore volume까지 통과시켜 각 통과된 pore volume에서의 토양세척 효율을 알아보았다. 본 실험조건에서 얻어진 세척용액의 최적 통과 속도는 0.31 ㎤$cm^{-2}$$min^{-1}$ 이었으며, 세척온도의 증가에 따른 세척효율의 향상은 2$0^{\circ}C$이상에서 크게 둔화되었다. 또한 보조용매의 사용량을 줄이기 위해 에탄올을 물로 1:3까지 희석한 결과 세척효율에 큰 영향이 없음을 알 수 있었다.

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.4
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• pp.117-123
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• 2008

The present study is directed at flow and heat transfer of $CO_2$ and oil mixtures in a circular tube. PAG and POE oils are considered in this study. Flow characteristics of $CO_2$ and oil mixtures have been investigated by flow visualization. Pressure drop has been measured in the range of operating mass flow rate from 0.1 to 0.4 kg/min in a circular tube. Heat transfer characteristics of $CO_2$/oil mixtures have been investigated using a counterflow heat exchanger. In case of pure liquid $CO_2$ as well as $CO_2$ and POE mixtures, flow are seen to be uniform so that $CO_2$ and POE oil are still miscible even at flowing state. However, it is found that $CO_2$ and PAG are not miscible. Pressure drop of $CO_2$/PAG mixtures are much higher than that of $CO_2$/POE mixtures as well as pure $CO_2$ at a fixed mass flow rate. As the concentration of POE oil is increased from 0 to 5 wt%, pressure drop is increased. However, heat transfer rate and heat transfer coefficient of $CO_2$/POE mixtures are much higher than that of $CO_2$/PAG mixtures. The f-factor correlation and Nusselt number correlation for $CO_2$/POE oil mixtures are suggested in this paper.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.646-651
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• 2007

This study has been conducted to select the suitable refrigeration oil for a $CO_2$ refrigeration system. The oil return is one of the most important characteristics for refrigeration oils. PAG and POE oils are considered as a test fluids in this study. An evaporator model is employed to simulate the evaporator of a $CO_2$ refrigeration system. Oil return characteristics has been investigated for $CO_2$/PAG and $CO_2$/POE mixtures in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $0^{\circ}C$ to $15^{\circ}C$. The results obtained indicate that oil return is decreased with an increase in the oil concentration and mixture temperature for both POE and PAG oils. It is also found that POE oil is seen to be superior than PAG oil in terms of oil return in an evaporator of a $CO_2$ refrigeration system.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.108-126
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• 1993

The functions of polyoxyethylene tocopheryl ethers [POE(n)TEs] in emulsion, solubilization and gel were studied. For emulsification of liquid paraffin, POE(10)TE showed better emulsifying effect in O/W emulsions than others tested. The effects of oil and polyol content on the formulation of W/O and O/W emulsions were also studied. In O/W emulsion, the viscosity was increased by increasing the liquid paraffin content, at about 70%, and slightly increased by increasing the propylene glycol content, However, in W/O emulsion, the viscosity was decreased by increasing the oil content, and also decreased by increasing the propylene glycol content, For solubilization of perfume oil, POE(18)TE showed better solubilizing effect than the others tested. The gelling effect of POE(n)TEs increased with ethylene oxide chain length up to 50 moles. The gelling property was evaluated for hardness and viscosity.

• Journal of Soil and Groundwater Environment
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• v.6 no.2
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• pp.39-47
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• 2001

According to a series of batch-scale washing tests, SDS+$POE_5$ and $POE_5$+$POE_14$ were determined for the applicable mixed surfactants. Because SDS+$POE_5$ showed slightly negative effects on the microbes in the toxicity tests, $POE_5$+$POE_14$((1:1) 1%) was chosen for this study. In the in-situ flushing experiments, the removal rate of endosulfan was 67% for the injection rate of 1.5L/min/$\textrm{km}^2$. And when methanol and ethanol were added as cosolvent, 75% and 81% removal efficiencies were achieved, respectively. In the tests of bioremediation after the application of in-situ flushing, the removal rates of contaminated soils having 13mg/kg dry soil and 3mg/kg dry soil as initial concentrations were 86% and 81%, respectively. There were no significant degradation after 24 hours. The major rate-limiting factor for the biodegradation of endosulfan might be the mass transfer from soil phase to liquid phase after 24 hours. With the addition of surfactant, 89% removal was achieved after 120 hours. Because the surfactant improved the mass transfer rate, the biodegradation of endosulfan was enhanced. When surfactant and cosolvent were added together, the adaptation period of microorganisms to the surfactant became longer and the removal rates were 84% and 83% for methanol and ethanol, respectively.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.65-74
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• 1998

To enhance the washing efficiency of soil polluted by hydrophobic organic compounds, the effects of electrolytes and monomeric organic additives on micelle formation and washing efficiency of mixed surfactant solutions were investigated in this study. The surface tensions and critical micelle concentrations(CMCs) of the single and mixed surfactant solutions[$POE_5$/SDS] supplemented by NaCl were measured to investigate the effects on washing efficiency, and the composition ratios of surfactants and NaCl were optimized for the efficient soil washing system. As the mixing ratio of $POE_5$/SDS was increased to 80%, the mixed surfactant with 0.01M NaCl showed more proportional increase of washing efficiency than the mixed surfactant without any salts. The 3% solution of $POE_5$ and SDS(80%/2o%) with 0.01M NaCl showed the washing efficiency of 90%. However, the washing efficiency was not enhanced by NaCl addition to the single surfactant solution of $POE_5$. The CMC of SDS(0.049%) was higher than that of $POE_5$(0.016%), but the CMCs of mixed surfactants were decreased as the mixing ratio of $POE_5$ was increased. Alcohols having longer chain and branched carbon chain were found to be desirable for the soil washing additives.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.5
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• pp.88-97
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• 1994

We persent a method for kinematic calibration of open chain mechanisms based on the product of exponentials (POE) formula. The POE formula represents the forward kinematics of an open chain as a product of matrix exponentials, and is based on a modern geometric interpretation of classical screw theory. Unlike the kinematic parameters in the POE formula vary smoothly with changes in the joint axes;ad hoc methods designed to address the inherent singularities in the D-H parameters are therefore are therefore unnecessary. After introducing the POE formula, we derive a least-squares kinematic calibration algorithm for general open chain mechanisms. Simulation results with a 6-axis open chain are presented.

• Journal of Science Education
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• v.33 no.1
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• pp.44-55
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• 2009

The research is aimed at investigating the development and application of high school biology classes utilizing discourse-typed inquiry learning program fitted with POE, and the corresponding effect on student's academic achievement and attitude toward science. 4 classes of 11th graders in a general high school located in Busan were selected as subjects. Biology I, 'Circulation' unit was lectured for 4 weeks (6 classes), and the experimental group underwent classes utilizing discourse-typed inquiry learning program fitted with POE. The control group was taught identical major learning contents, but based on the learning objectives and research activities provided by Biology I textbook. As a result of application, first, the discourse-typed inquiry learning program fitted with POE exhibited positive consequences of linking previously acquired knowledge and the new learning attained through experiments, as well as not only improving the students' problem solving capacity through diverging questions from the teachers to drive the students' higher-level contemplation, but also enhancing student academic achievement by assisting their logical thinking. Second, POE-fitted discourse-typed inquiry learning program rendered presupposing session of the experiment that resulted in drawing learners' attention in advance, and incited active participation in the learning process through solving the contradiction between what was actually observed and what was expected, which eventually proved to lay out positive impact on students' attitude toward science.