• Journal of Environmental Science International
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• v.3 no.4
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• pp.403-408
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• 1994

Catalytic slurry reactors, in which a solid maintained in the rom of fine particles suspended in a liquid, are frequently used in chemical and biochemical and industries. In these processes the particle loading is normally low so that the effects of particles on the liquid-film mass transfer coefacent and the gas-liquid interface area are assumed to be negligible. But it is known from the works, amongst others, that the finely powdered activated carbon can increase the gas-liquid mass transfer significantly in surface-aerated reactors. The stirred cell (13.2cm inside diameter) contained four baffles and at the stirring speeds range of 80 ∼ 300ppm, the gas-liquid interfacial area could be considered as that of the cross section of the vessel (that is, 130.1cm2). When the stirrer speeds were increased, the effective interfacial area was slightly higher than the geometric area and was obtained experimentally from the Danckwerts plots. Key Words : gas-liquid interfacial area, Duckwert's Plot stirred dell. mass transfer coefficient.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.138-142
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• 2007

본 연구는 고점도 유체의 혼합을 위한 교반기 설계의 기초연구로서 스크류 형상의 임펠러(또는 헬리컬 임펠러)를 가지는 교반기 내의 유동과 이에 따른 유체혼합 특성을 수치해석을 통해 가시화한 것이다. 이와 더불어 양호한 혼합효과를 가져다 줄 것으로 예상되는 엇갈림형 스크류 임펠러의 모델을 제안하였다. 수치해석상의 유체는 고점도의 Newton유체로 가정하였으며 임펠러의 회전속도는 6[rpm]으로 아주 작게 하여 저 레이놀즈수(약 Re=3)에서 혼합효과를 연구하였다. 또한 각종 설계 파라미터를 변화시켜 혼합 양상의 차이를 분석하여 설계에 반영하고자 하였다.

• Journal of Korea Foundry Society
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• v.23 no.3
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• pp.130-136
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• 2003

Rheocasting of AZ91D magnesium alloys yielded the microstructure consisted of the spherical primary particles in the matrix which is different from conventional casting. Rheocast ingots were produced under various processing conditions using batch type rheocaster. Morphology of primary particles was changed from rosette-shape to spherical shape with increasing stirring rate$(V_s)$ and decreasing isothermal stirring temperature$(T_s)$. With increasing $V_s$, more effective shearing between the particles occurred rather than the agglomeration and clustering, so the primary particle size decreased. But with decreasing $T_s$, primary particle size increased mainly due to sintering and partially Ostwald ripening. The sphericity of primary particles increased with increasing $V_s$ and decreasing $T_s$ due to enhanced abrasion among the primary particles. The uniformity of primary particle size increased with increasing Vs and $T_s$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.384-390
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• 2009

Extraction characteristics of citron (Citrus junos Sieb. ex Tanaka) seeds and functional properties of corresponding extract were monitored by response surface methodology (RSM). Maximum extraction yield of 20.23% was obtained at extraction temperature of $50.23^{\circ}C$, extraction time of 3.03 hr, and shaking velocity of 400.06 rpm. At extraction temperature, extraction time, and shaking velocity of $49.88^{\circ}C$, 2.72 hr, and 400.39 rpm, respectively, maximum polyphenol content was 4.37 mg/g. At extraction temperature, extraction time, and shaking velocity of $50.28^{\circ}C$, 3.42 hr, and 399.96 rpm, respectively, maximum electron donating ability (EDA) was 49.69%. Maximum nitrite scavenging activity (NSA) was 47.79% at extraction temperature, extraction time, and shaking velocity of $49.19^{\circ}C$, 0.68 hr, and 602.95 rpm, respectively. Based on superimposition of 3-dimensional RSM with respect to extraction yield, polyphenol, EDA, and NSA, optimum ranges of extraction conditions were extraction temperature of $50^{\circ}C$, extraction time of about 3 hr, and shaking velocity of 400 rpm.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.763-770
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• 1997

The separation of benzene-cyclohexane mixture using (O/W)/O emulsion liquid membrane was studied. The operating parameters which can affect the selectivity, benzene yield, and emulsion size distribution were examined and determined by the batch type operation. The unsteady state and steady state extraction behavior in continuous pulse stirred reactor(CPSR) were verified. The optimum conditions for benzene selectivity and yield in batch operation were as follows; emulsion mixing intensity 4000 rpm, Tween 80 concentration 0.4%, volume ratio of membrane phase to internal phase 0.75, volume ratio of dispersed phase to continuous phase 0.5, and permeation time 10 minutes, As impeller speed increased and the microdrop holdup decreased, the Sauter mean diameter decreased. Turbulence damping parameter of modified Calabrease correlation considering microdrop holdup was 2.28. The optimum conditions of continuous operation were as follows; agitation speed 300 rpm, pulse frequence 2 times/sec, flow rate of continuous phase 30ml/min, and flow rate of emulsion phase 12.0ml/min.

• Korean Journal of Food Science and Technology
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• v.14 no.1
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• pp.49-56
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• 1982

The effects of measurement conditions on the emulsifying capacity(EC) and emulsion stability(ES) of proteins were studied in order to develop laboratory standard methods for the evaluation of emulsifying properties. The EC of proteins decreased with the increments of protein concentration and mixing rate. It increased with the increasing oil addition rate up to 0.8 ml/sec, but did not change at $0.8{\sim}1.2\;ml/sec$. The addition of sodiumchloride enhanced EC of proteins, attaining to the highest EC at 0.3M NaCl for Pro-Fam and 0.1M NaCl for Na-caseinate. The ES of Pro-Fam was higher than that of caseinate. The ES was increased by the increments of protein concentration, oil addition volume, mixing rate and mixing time. The EC and ES showed a close relation to the NSI of proteins, reaching to the lowest values of EC and ES at the isoelectric regions of proteins. The laboratory methods for measurements of emulsifying properties of proteins were established. The emulsifying properties of a laboratory-made soybean protein isolate were compared to those of commercial products by using the methods.

• KSBB Journal
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• v.4 no.2
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• pp.78-86
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• 1989

The effective saccharification of cellulosic biomass to glucose is the most critical step for the conversion of renwable biomass to alternative liquid fuel. The enzymatic hydrolysis of biomass can be significantly enhanced provide the attrition milling media is added during hydrolysis. The enhancing mechanism of hydrolysis reaction in an agitated bead system was investigated. An attrition-reactor (bioattritor) which installed specially designed torque measuring apparatus was developed, and the potimal saccharification conditions of bioattritor were determined. The relationship between the power consumption required for agitation of attrition-milling media and enhanced extent of hydrolysis of biomass was compared to evaluatic economic feasibility of the process.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.358-362
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• 2004

본 연구에서는 가교화 ${\beta}-CD$로 크림치즈의 콜레스테롤을 효과적으로 제거하는 실험을 수행 하였으며, 크림치즈의 이화학적 변화와 관능적 특성을 살펴보았다. 크림치즈를 만들기 위한 유지방 함량 36%의 크림을 가교화 ${\beta}-CD$로 처리 시 콜레스테롤 제거 최적 조건은 가교화 ${\beta}-CD$ 10%를 첨가해 교반온도 $20^{\circ}C$, 교반시간 30분, 교반속도 800rpm으로 실험한 결과 콜레스테롤 제거율이 평균 82.0%로 나타났다. 가교화 ${\beta}-CD$처리 크림치즈는 short-chain fatty acid의 경우 저장 기간이 지남에 따라 control과 powder ${\beta}-CD$ 처리한 크림치즈에 비해 저급 지방산 생성에 변화가 거의 없고, 쓴맛을 내는 아미노산의 경우 저장 기간 동안 control과 powder ${\beta}-CD$처리 크림치즈에 비해 생산량이 현저하게 적었다. 또한 가교화 ${\beta}-CD$처리 크림치즈의 조직검사에서 다른 항목에서보다 저장 기간 동안 응집성이 변함이 없으며 그 수치가 높게 평가되었다. 관능검사 결과, 가교화 ${\beta}-CD$처리 크림치즈는 저장 기간 동안 쓴맛의 증가가 거의 없었고 전체적인 기호도 또한 높았다. 위 실험 결과에 따르면, 가교화 ${\beta}-CD$ 사용결과 cholesterol 제거율이 높으며, 제품에 적용시 재활용이 가능하고 품질이 향상되므로 이를 유가공 산업에 활용이 가능할 것으로 기대된다.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.317-321
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• 2005

본 연구결과, 콜레스테롤 제거 크림치즈를 만들기 위한 유지방 함량 36%의 크림의 콜레스테롤 제거 최적 조건은 adipic acid로 가교시킨 ${\beta}-CD$ 첨가량 10%, 교반온도 $20^{\circ}C$, 교반시간 30분, 교반속도 800rpm 이었으며, 이 때 콜레스테롤 제거율은 평균 91.42%로 나타났다. 가교화 ${\beta}-CD$ 처리 크림치즈의 관능검사 결과, 가교화 ${\beta}-CD$ 처리 크림치즈는 control과 powder ${\beta}-CD$ 처리한 크림치즈에 비해 저장 기간 동안 쓴맛의 증가가 거의 없었고, 빵에 발리는 정도도 매우 우수하였으며, 전체적인 기호도 또한 높았다. short-chain fatty acid의 경우 저장 기간이 지남에 따라 가교화 ${\beta}-CD$ 처리 크림치즈는 control과 powder ${\beta}-CD$ 처리한 크림치즈에 비해 저급 지방산 생성에 변화가 거의 없었다. 조직검사에서 가교화 ${\beta}-CD$ 처리 크림치즈는 저장 기간 동안 control에 비해 응집성, 탄력성, 점착성의 변화가 없으며 그 수치가 높게 평가되었다. 또한 가교화 ${\beta}-CD$의 재활용률은 97.82%로 매우 높게 나타났다. 위 실험 결과에 따르면, 가교화 ${\beta}-CD$는 콜레스테롤 제거율이 높으며, 제품에 적용 시 품질이 향상될 뿐만 아니라, 재활용률도 높아 이를 유가공 산업에 다양하게 활용이 가능할 것으로 기대된다.

• Korean Journal of Materials Research
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• v.3 no.5
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• pp.529-537
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• 1993

The mecllanical properties of AI/TiCp composite fabrication by liquid mixing was investigat ed. The composites, containing 10 wt% Tic. were producwi using induction furnace with mechanical stirring. The amounts of' 1.5wt% Mg were, added to wetting agents. Thr presence of aluminum in TiC composites showed rnhanced strengrh without loss of ductility at room and clrvated temperatures. Espe cially, wear resistance was found to dramatically irnprovc. I3ul excess stirring d~terrninrd the mect~ani~ cal properties. Approximate values at present work were 500 rpm. There was no inrerfacial reaction of any kind and the interface remains clearly deineated.