• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.510-518
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• 2018

Recently, lots of interests have been concentrated on the scrubber system that abates waste gases produced from semiconductor manufacturing processes. An effective design of the thermal decomposition reactor inside a scrubber system is significantly important since it is directly related to the removal performance of pollutants and overall stabilities. In the present study, a computational fluid dynamics (CFD) analysis was conducted to figure out the thermal and flow characteristics inside the reactor of wet scrubber. In order to verify the numerical method, the temperature at several monitoring points was compared to that of experimental results. Average error rates of 1.27~2.27% between both the results were achieved, and numerical results of the temperature distribution were in good agreement with the experimental data. By using the validated numerical method, the effect of the reactor geometry on the heat transfer rate was also taken into consideration. From the result, it was observed that the flow and temperature uniformity were significantly improved. Overall, our current study could provide useful information to identify the fluid behavior and thermal performance for various scrubber systems.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.274-278
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• 2013

Automatic transmission fluid (ATF) is used as an automatic transmission in the vehicle or as a characterized fluid for automatic transmission. Recently, vehicle manufacturers usually guarantee for changing fluids over 80000~100000 km mileage or no exchange. However, most drivers usually change ATF below every 50000 km driving distance when driving in Republic of Korea according to a survey from the Korea Institute of Petroleum Management which can cause both a serious environmental contamination by the used ATF and an increase in the cost of driving. In this study, various physical properties such as flash point, pour point, kinematic viscosity, dynamic viscosity at low temperature, total acid number and four-ball test were investigated for both fresh ATF and used ATF after the actual vehicle driving distance of 50000 km and 100000 km. It was shown that most physical properties were suitable for the specification of ATF, but the foam characteristics of the used oil after running 100000 km was unsuitable for the specification of fresh ATF. Therefore, the exchange cycle of ATF every 80000~100000 km driving distance is recommended considering great positive contributions to preventing environmental pollution and reducing driving cost.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.687-693
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• 2019

As the hydrogen fuel cell market is expanded starting from hydrogen electric vehicle and power generation field, the demand for fuel cells and hydrogen increases recently. Therefore, research works on fuel cell durability and fuel efficiency are required in order to activate the fuel cell market and commercialization. A dead-ended anode system was used in this study to optimize the fuel cell performance and fuel efficiency. The effect of purge condition according to the applied current and hydrogen supply pressure on the fuel cell performance were evaluated. In addition, the influence of water back diffusion on the different electrolyte membrane thickness was analyzed. The accumulated water was purged with a solenoid valve in the case of 3% voltage decrease in the dead-ended anode system. The experiment was performed with the hydrogen supply pressure of 0.1~0.5 bar and purge duration of 0.1~1 second. A maximum fuel efficiency of 98.9% was achieved under the purge duration of 0.1 s and hydrogen supply pressure of 0.1 bar with a NR 211 (25.4 um) membrane. However, the fuel cell performance decreased in a long-term operation due to some frequent flooding. The fuel efficiency and purge interval increased due to decreased back diffusion rates of the water and nitrogen with a NR 212 (50.8 um) membrane.

• 대한공업교육학회지
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• v.38 no.2
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• pp.136-155
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• 2013

The purpose of this study is to analysis the recognition of engineering professionals in Primary and middle school education. For the study, survey was proceeded through experts in engineering. The result of research follows. First, experts in engineering recognized that engineering has a significant impact in the national economic development and competitiveness. Experts in engineering, had a recognition consistent to some extent for engineering. and we have found engineering's own characteristics that emphasize "problem solving and design, innovation and creativity, economy optimization". Second, experts in engineering recognized that engineering education in Primary and middle school rarely take place, and also does not provide enough information for students. Third, experts in engineering recognized that engineering education is very needed in Primary and middle school. Through this, students can understand creative design problem-solving process. In addition, Experts of engineering, have a variety of educational demands for School level to the level of engineering education should start, level educational purposes, how to apply effective and so on.

• 한국유가공학회:학술대회논문집
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• 2005.06a
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• pp.107-116
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• 2005

최근 사회의 다변화, 고령화 및 소비자의 다양한 욕구 증대 등으로 인하여 세분화된 소비계층을 겨냥한 다양한 신제품들이 출시, 판매되고 있는 반면, 일반 백색시유를 제외하고는 제품의 라이프사이클이 크게 줄어드는 경향을 보이고 있다. 건강기능식품 시대의 도래와 함께 첨단 기능성 소재들이 속속 등장하고 있으며, 유가공업계도 이들 소재를 응용한 연구개발과 공정개선을 통한 신제품 출시에 박차를 가하고 있다. 그러나 음용유 시장에서 절대적인 비중을 차지하고 있는 시유부문은 저출산율과 수입개방 등의 악재로 인하여 점차적인 감소 추세에 접어들고 있다. 따라서 국내 유가공업체는 원유소비 증대와 유제품 경쟁력을 확보하기 위해 유제품의 다양화, 고급화를 위한 기술개발 및 유제품의 적극적인 홍보 등의 전략이 필수적이다. 이를 위해서는 종래 단순가공에 의한 유제품 생산에서 탈피하여 새로운 공정 개발, 신물질 탐색 등으로 생산비 절감, 수율 증대, 다양한 형태의 유제품 개발, 그리고 기능성 소재의 탐색 등 건강 지향적 기능성 식품 개발에 노력을 해야 할 것이며 국공립 및 사립대학교 및 정부 출연기관과 일반 유업체의 공동과제 실시 확대로 기능성 식품에 대한인식제고가 필요할 것이다. 또한, TV 매체를 통한 홍보, 우유의 교과서 반영, 자조금 활성화 등으로 어릴 때부터 우유 먹는 습관을 형성하여 시유 소비기반 확대를 도모해야 할 것임과 아울러 교육당국과 협력하여 학생과 영양교사를 대상으로 한 우유에 대한 체계적인 교육프로그램 실시 및 중 ·고등학교 급식화대 추진 등 관련 기관과의 협력체계 구축을 통한 낙농진흥활동을 전개하여야 한다.유아의 창의성수준을 더 높게 평가하였다. 그러나 아버지와 교사간 평가의 상관은 유의하지 않았는데 이는 아버지의 평가수준이 매우 객관적인 것은 아님을 시사한다. 셋째, 창의적인 유아와 일반 유아 아버지 양육태도에서는 유의한 차이를 보였는데 특히 애정-적대요인과 자율-통제요인에서 창의적인 유아와 일반 유아간의 차이가 있는 것으로 나타났다. 넷째, 유아의 창의성과 아버지 양육태도간의 상관관계분석결과 애정적 양육태도와 유창성, 독창성간의 상관이 유의하였다. 집단별 분석시 창의적인 유아를 둔 아버지의 양육태도와 유아의 창의성간에는 상관이 없는 것으로 나타났고, 일반 유아의 아버지 양육태도와 유아의 창의성간의 상관에서는 아버지 양육태도의 성취-비성취 요인에서와 창의성제목의 추상성요인에서 상관이 있는 것으로 나타났다. 따라서 창의성이 높은 아동의 아버지의 양육태도는 일반 유아의 아버지와 보다 더 애정적이며 자율성이 높지만 창의성이 높은 아동의 집단내에서 창의성에 특별한 영향을 더 미치는 아버지의 양육방식은 발견되지 않았다. 반면 일반 유아의 경우 아버지의 성취지향성이 낮을 때 자녀의 창의성을 향상시킬 수 있는 것으로 나타났다. 이상에서 자녀의 창의성을 향상시키는 중요한 양육차원은 애정성이나 비성취지향성으로 나타나고 있어 정서적인 측면의 지원인 것으로 밝혀졌다.징에서 나타나는 AD-SR맥락의 반성적 탐구가 자주 나타났다. 반성적 탐구 척도 두 그룹을 비교 했을 때 CON 상호작용의 특징이 낮게 나타나는 N그룹이 양적으로 그리고 내용적으로 더 의미 있는 반성적 탐구를 했다용을 지원하는 홈페이지를 만들어 자료 제공 사이트에 대한 메타

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.509-513
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• 2010

Recently, an amount of waste electronic devices such as LED and trichromatic fluorescent lamp has increased with the development of electronic industry. Reportedly, rare earth metals such as yttrium and europium have been discovered in the waste electronic devices. In order to improve the selectivity of yttrium and europium, the effects of the following factors on recovery experiment have been considered : i) fatty acids with various alkyl chain lengths, ii) the concentration of extractant, and iii) pH. The results show that the extraction efficiencies decrease at the same pH with decreasing the concentration of extractant and so $pH_{0.5}$ (That value of pH in an aqueous phase at which the distribution ratio is unity at equilibrium: 50% of the solute is extracted (E = 0.5) only when the phase ratio is unity.) moves into higher pH. The highest selectivity of yttrium and europium was obtained with tetradecanoic acid as extractant. The extraction mechanism of yttrium and europium was varied with the change of concentration of the tetradecanoic acid. $MR_3$single-species was formed from the yttrium and europium ion in the extractant concentration less than 0.1 M. On the other hand, the yttrium or europium ion is solvated with three molecules of tetradecanoic acid monomer like $MR_3{\cdot}$ 3RH in the extractant concentration more than 0.1 M.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.121-133
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• 2014

Block copolymers including ABA triblock architectures are useful as thermoplastic elastomers and toughened plastics depending on the relative glassy and rubbery content. These materials can be blended with other polymers and utilized as additives, toughening agents, and compatibilizers. Most of commercially available block copolymers are derived from petroleum. Renewable alternatives are attractive considering the finite supply of fossil resources on earth and the overall economic and environmental expenses involved in the recovery and use of oil. Furthermore, tomorrow's sustainable materials are demanding the design and implementation with programmed end-of-life. The present review focuses on the preparation and evaluation of new classes of renewable ABA triblock copolymers and also emphasizes on the use of carbohydrate-derived poly(lactide) or plant-based poly(olefins) having a high glass transition temperature and/or high melting temperature for the hard phase in addition to the use of bio-based amorphous hydrocarbon polymers with a low glass transition temperature for the soft components. The combination of multiple controlled polymerizations has proven to be a powerful approach. Precision-controlled synthesis of these hybrid macromolecules has led to the development of new elastomers and tough plastics offering renewability, biodegradability, and high performance.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.259-265
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• 2012

Differently from fly ash, the bottom ash produced from thermal power generation has been treated as an industrial waste matter, and almost reclaimed or was applied with the additive of the part concrete. Bottom ash has various problems to use with the aggregate. Bottom ash is lighter than typically the sand or the gravel and it's physical properties (compressive strength etc.) is somewhat low because of high absorptance. In order to manufacture the ash concrete, we used a bottom ash as a main material and a pure sulfur as a binder. In this study, fundamental research methods that vary the grain-size of bottom ash and the ratio of sulfur vs ash were investigated to improve the quality of ash concrete such as compressive strength. Bottom ash in this research which occurs from domestic 4 place power plants, was checked physical and chemical properties. The compressive strength seems the result which simultaneously undergoes an influence in content of the sulfur and Bottom ash grain-size. We got the result of the maximum 92 MPa. The compressive strength was high result for grain size below 1.2 mm and high sulfur content.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.413-420
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• 2008

Over the past decade, there have been significant advancement in the field of electrospinning area. This study has focused on preparing yarn using polycarbonate (PC) nanofibers including modified multi-walled carbon nanotube (mMWNT) by solution electrospinning process using the mixture of solvents consisting of tretrahydronfuran (THF) and N,N-dimethylformamide (DMF). In order to enhance the dispersion, MWNT was chemically modified. TEM analysis for the prepared PC/mMWNT nanofibers reveals that mMWNT was well-dispersed into the PC nanofiber matrix. Also with increasing contents of mMWNT, thermal stability of PC/mMWNT nanofibers was improved than that of PC nanofibers. Moreover when 3 to 5 wt% of mMWNT was added, the nanofibers showed good electrical properties expecting antistatic effect, ranging 109.1~109.5 ${\Omega}$. It was confirmed that the multi-filament fibers using PC/mMWNT had $60{\sim}100{\mu}m$ in diameter and 4~5 cm in length.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.10-17
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• 2013

Heavy oil residue upgrading process was being used in conventional refinery process. Recently, as the importance of non conventional energy development is growing up, the commercial projects of heavy oil upgrading are getting more active than before. For having competitive business model in the resource competition, non conventional energy development should be considered as an important business strategy. In developing oil sands, extra heavy oil, and shale gas, canadian oil sands and extra heavy oil have great importance in substitution of conventional oil consumption. In oil sands development, the bitumen, which is extracted from oil sands, has great value after upgrading or refining process. Similar process is being used current conventional refinery process. The bitumen is highly viscous hydrocarbon. This bitumen includes impurities which can not be treated in conventional refinery process. As this reason, specified process is needed in bitumen or extra heavy oil upgrading process. Moreover, there will be additional specified facilities in the process of production, transportation and marketing. In oil sands, there are various kinds of commercial upgrading process. Extraction, dilution, coking and cracking method were being used commercially.