• Title/Summary/Keyword: Various reducing conditions

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The Effects of Drawing Conditions on Physical Properties of the Drawn Worsted Yarns (I) (연신공정 조건이 소모연신사의 물성에 미치는 영향 (I))

  • Han, Won-Hee;Kim, Seung-Jin;Kim, Sang-Ryong
    • Textile Coloration and Finishing
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    • v.22 no.1
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    • pp.51-60
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    • 2010
  • This research works on the effects of drawing conditions on the physical properties of the drawn worsted yarns. The drawn worsted yarns were made by the yarn drawing system under various drawing conditions such as concentration of reducing agent, draw ratio, setting time of drawn yarn, and concentration of oxidizing agent. The drawn worsted yarns from 2/80Nm to 2/90Nm were obtained from 2/60Nm worsted yarns, the surface and cross-sectional shapes and tensile properties of these various specimens were measured and discussed with the various drawing conditions. The drawing of worsted yarn made constituent wool fiber scratched and made it changing to polygonal cross-sectional shape. The tenacity and modulus were increased with draw ratio and concentration of reducing agent. And tensile strain was increased with draw ratio, which decreased with concentration of reducing agent.

An Experimental Study on Conversion of Reducing Agent from Aqueous Urea Solutions under Low Reaction Temperature (저온 반응장에서 요소 수용액의 환원제 전환에 관한 실험적 연구)

  • Ku, Kun Woo;Hong, Jung Goo
    • Journal of ILASS-Korea
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    • v.20 no.1
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    • pp.20-27
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    • 2015
  • Urea-SCR which is one of the aftertreatment technologies for reducing the NOx emission is widely used. An experimental study was performed to investigate urea decomposition under various thermo-fluid conditions, with different temperatures and velocities of inflow gas, and urea solution quantities. 40 wt. % aqueous urea solutions were used in this study. The inflow gas conditions were similar to the exhaust conditions of a large marine engine. The spray performance of urea solution injector was identical under all experimental conditions. The conversion efficiency of $NH_3$ was larger than that of HNCO under all experimental conditions, unlike for the theoretical thermolysis reaction.

Effects of Extraction Conditions on the Componential Extraction of Brown Seaweed (Undaria pinnatifida)

  • Park, Nan-Young;Kim, In-Sun;Jeong, Yong-Jin
    • Preventive Nutrition and Food Science
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    • v.13 no.4
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    • pp.321-326
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    • 2008
  • In order to improve the market competitiveness of the processed products of Undaria pinnatifida, various extraction conditions of Undaria pinnatifida were examined to determine the optimal conditions for the extraction of its valuable components. The highest level of alginic acid content was detected after 90 min of typical extraction or after 20 min of pressure extraction, after which the levels decreased slightly. The concentrations of reducing sugar and crude protein were also high after 90 min of typical extraction. Both alginic acid and reducing sugar were extracted in greater amounts using pressure extraction. The reducing sugar content was $2.8{\sim}3.2$ times higher using pressure extraction rather than typical extraction. Furthermore, the extraction results were superior with the, pressure extraction method. The appropriate temperature and duration of extraction were found to be $120^{\circ}C$ for 20 min. The use of a single enzyme yielded better results during extraction compared to the use of a mixture of enzymes. 20 min of pressure extraction followed by the addition of 0.1% pectinase and 2 hr of further extraction at $50^{\circ}C$ yielded high contents of alginic acid and reducing sugar from Undaria pinnatifida.

A Study on the Supportive Design Conditions for the Hospital Stress in Korea (한국 병원의 스트레스에 대응한 치유환경 조건에 관한 연구)

  • Choi, Kwang-Seok;Kim, Khil-Chae
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.8 no.1
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    • pp.61-67
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    • 2002
  • It is the well-documented fact that most patients experience considerable stress in hospital. Stress is also a problem for families of patients, visitors and for hospital staffs. To promote wellness. It is fundamentally important that hospital be designed to foster copying with stress. By Literature review, this study presents stressors of patients, families, hospital staffs and various healing design elements. And then, it cross-checks the relations between stress-reducing conditions and healing design elements. Finally, this presents the healing design conditions for each stress-reducing conditions of patients, families and staffs.

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Asswssment of natural attenuation for Gasoline contaminated soil under various reducing conditions

  • 오인석;이시진;장순웅
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.04a
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    • pp.255-259
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    • 2004
  • 본 연구에서는 유류오염 토양현장샘플을 이용한 실험실 규모의 회분식 실험을 통해 다양한 환원조건하에서 BTEX와 MTBE의 자연정화 평가 및 현장 생복원 기술 적용 타당성을 검토하는데 있다. 첫째, 오염토양과 비오염 토양에서 충분한 전자수용체의 존재는 유류오염물질의 생분해능을 증가시킬 수 있었음 알았다. 둘째, 같은 토양이라도 전자수용체의 종류와 유류오염물질의 특성에 따른 생분해능의 다양성을 확인할 수 있었다. 셋째, BTEX에 비해 MTBE의 분해가 매우 느림을 확인하였다. 본 실험은 아직 초기 단계의 실험으로 현장 조건을 충분히 만족 시키지는 못한다. 추가적인 pH 변화에 따른 전자수용체의 이용 특성 및 토양-지하수 microcosm test, 혐기성 생분해 부산물인 $CO_2$, $N_2$ 또는 $N_2$O, TBA의 연구가 실시되어야 하겠다.

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A Study on the Effects of Insulating Material Barrier on the Surface Creepage over Discharge (연면방전의 특성과 절연체의 영향 및 그 응용)

  • Sung Won Rhee
    • 전기의세계
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    • v.19 no.2
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    • pp.12-17
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    • 1970
  • In the design of electrical equipment insulation, it is customary to place pressboard and other insulating material at right angle to the electrical discharge path, which is based on the insulation tests performed on equipment under various conditions such as types of insulation, applied voltage and other unique situations. Since electrical equipment manufacturing started only recently, there is a scarcity of available data on insulation problems, which make it difficult for the design engineers. The author untook this study to provide such analytical design data for various conditions based on the experiment conducted on the equipment being manufactured, thus reducing possible errors in the process.

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NOx Conversion Characteristics of HC-LNT System according to Secondary Injection Conditions in a Diesel Engine (디젤엔진에서 2차 분사조건에 따른 HC-LNT 시스템의 NOx 변환 특성)

  • Park, Jin-Kyu;Oh, Jung-Mo;Lee, Ki-Hyung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.5
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    • pp.130-137
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    • 2012
  • Automotive engines need strategies to satisfy with the emission regulations in terms of PM and NOx. HC-LNT (Hydrocarbon-Lean NOx Trap) with secondary injection system is considered as more practical technology in order to cope with emission regulations. The HC-LNT system, which is using diesel fuel itself as a reducing agent, absorbs NOx in lean exhaust gas condition and releases NOx in rich exhaust gas conditions. In this system, inappropriate amounts of reducing agent will slip through the LNT without the profits of conversion and cause additional emission problems. Therefore, the suitable amount of reducing agent should be supplied into the catalytic converter. In this research, engine emission test was conducted to optimize injection quantity at the various engine test conditions. Different exhaust layouts and catalyst shapes have been studied and extension unit which makes better uniformity of exhaust gas was used for HC-LNT system. From this results, the effect of secondary injection conditions on NOx conversion characteristics of HC-LNT was clarified.

Anaerobic Degradation of Aromatic Compounds by Microorganisms in Paddy Field

  • Katayama, A.;Yoshida, N.;Shibata, A.;Baba, D.;Yang, S.;Li, Z.;Kim, H.;Zhang, C.;Suzuki, D.
    • 한국환경농학회:학술대회논문집
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    • 2011.07a
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    • pp.128-135
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    • 2011
  • Consortia demonstrated the high capacities of anaerobic degradation of various aromatic compounds, which were successfully enriched from gley paddy soils under different conditions. Phenol and cresol was decomposed anaerobically using nitrate, ferric oxide or sulfate as electron acceptors. Biphenyl was degraded to $CO_2$, especially without addition of external electron acceptor. Alkylphenols with middle length of alkyl chain, were co-metaboliocally degraded with the presence of hydroxylbenzoate as the co-substrate under nitrate reducing conditions. The microorganisms responsible for the anaerobic co-metabolism was Thauera sp. Reductive dechlorination activity was also observed for polychlorophenols, fthalide, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins with the presence of lactate, formate or $H_2$ as electron donor. The fthalide dechlorinator was classified as Dehalobacter sp. Coupling of two physiologically-distinct anaerobic consortia, aromatic ring degrader and reductive dechlorinator, resulted in the mineralization of pentachlorophenol under anaerobic conditions. These results suggested that gley paddy soils harbored anaerobic microbial community with versatile capacity degrading aromatic compounds under anaerobic conditions.

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A Study on the Optimal Cutting conditions for Mild Materials (연질재료의 최적 절삭조건설정에 관한 연구)

  • 최상련
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.1
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    • pp.112-118
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    • 1999
  • Aluminum alloy, which is advantageous to machining and injection, makes a great contribution to shortening in delivery time, infection cycle time and reducing expense. This study presents machining conditions for mild materials and describes the difference between theoretical and practical machined surface roughnesses affected by various machining conditions. Machining results have been evaluated and analyzed under varying machining conditions. Special properties of the mild materials have been presented by the quantitative analysis and the optimal machining condition has been proposed for the mild materials.

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