• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.291-294
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• 2005

In the present study, a numerical analysis was performed for interior connections of continuous flat plate to analyze the effect of column section shape on the behavioral characteristics of the connections. For the purpose, a computer program for nonlinear FE analysis was developed, and the validity was verified. Through the parametric study, the variations of shear stress distribution around the connection were investigated. According to the result of numerical analysis, the column section shape has a serious effect on the behavior of the connections. As the length of the cross section of column in the direction of lateral load increases, the effective area and the shear strength at the sides providing the torsional resistance decrease considerably. Therefore the strength model for the flat plate-column connections should be modified by considering the effect of column section shape on the behavior of the connections.

• KSBB Journal
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• v.18 no.6
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• pp.455-460
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• 2003

This study was designed to find out the rapid fermentation of soy sauce from koji hydrolyzates using air bubble column reactor packed with coimmobilized mixed culture system. Continuous ripid production was performed by coimmobilized Z. rouxiii BH-90 and C. versatilis BH-91. Coimmobilized cells of Zygosaccharomyces rouxii BH-90 and Candida versatilis BH-91 mixture cells in the column reactor produced 2.8％ ethyl alcohol and 18mg/L 4-ethylguaiacol over 96 hours under the optimal conditions. Coimmobilized cells produced 2.30∼2.4% ethyl alcohol during 30 days, and decreased gradually from 40 days to 70 days. Also coimmobilized cells produced 4-ethylguaiacol at the constant rate of 16∼18mg/L and decreased gradually after 40 days. Final product of soy sauce contained 2.4% ethyl alcohol and 18mg/L 4-ethylguaiacol. However, amino acid compositions of soy sauce were consisted of predominantly glutamic acid, leucin, arginine, aspartic acid, Iysine and valine, which were more than 50% of total amino acid.

• Steel and Composite Structures
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• v.16 no.2
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• pp.187-201
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• 2014

A new through-beam connection system for a concrete filled steel tube column to RC beam is proposed. In this connection, there are openings on the steel tube while the reinforced concrete beams are continuous in the joint zone. The moment and shear force at the beam ends can be transferred to column by continuous rebar and concrete. The weakening of the axial load and shear bearing capacity due to the opening of the steel tube can be compensated by strengthening steel tube at joint zone. Using this connection, construction of the joint can be made more convenient since welding and hole drilling in situ can be avoided. Axial compression and reversed cyclic loading tests on specimens were carried out to evaluate performance of the new beam-column connection. Load-deflection performance, typical failure modes, stress and strain distributions, and the energy dissipation capacity were obtained. The experimental results showed that the new connection have good bearing capacity, superior ductility and energy dissipation capacity by effectively strengthen the steel tube at joint zone. According to the test and analysis results, some suggestions were proposed to design method of this new connection.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.45-45
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• 1993

괄루근으로부터 분리된 다당류에 대하여 continuous gel electrophoresis, SDS-Polyacrylamide gel eletrophoresis, ion exchange column chromatography, Hydroxyapatite column chromatography 및 Gel filtration등의 방법을 이용하여 다음과 같은 결과를 얻었다. 1) 황산암모늄 분별침전법에 의한 렉틴의 정제도는 초추출물의 4.85배이며 DEAE Sephadex A-50 column chromatography법에 의한 정제도는 24.17배로 나타났고, 마지막 정제단계인 Sephacryl S-200 gel filtration에 의한 정제도는 47.34배로 나타났다. 2) 정제된 렉틴의 분자량은 60,000da1ton으로 나타났다. 3) 사람의 혈액형에 따른 응집효과는 90-100％로 특이성은 없었다.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.3
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• pp.116-126
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• 1995

The purpose of this study was to investigate the removal of ammonium nitrogen by biological nitrification in raw water containing LAS using BAC. At batch teats, LAS removal by ozone followed the first order reaction, and the rate constants(k) by ozone dose 1, 3mg/min.L were $0.040min^{-1}$, $0.062min^{-1}$ respectively. Therefore, the more ozone was dosed, the higher LAS was removed The reaction between ozone and ammonium nitrogen also followed the first order, and rate constants(k) at pH7,8 and 9 were $8.9{\times}10^{-4}min-1$, $3.8{\times}10^{-3}min^{-1}$, and $2.9{\times}10^{-2}min^{-1}$ respectively at ozone dose of 3mg/min.L . Therefore, ammonium nitrogen was little removed by ozone under neutral pH of 7. The continuous flow apparatus had four sets composed of a ozone contacter and a GAC column. Through continuous filtration test for 50days, the following conclusions were derived; (1) LAS was removed 23%, 30% respectively by ozone dose 1, 3mg/L, and was not detected in all column effluents during the period of experiment. Therefore, it appeared that adsorption capacities of each column still remained. (2) Ammonium nitrogen concentration after ozone contact varied little in raw Water because pH of raw water was from 6 to 7, and was transfered to nitrite and nitrate within GAC columns as the result of staged nitrification. After 30days, nitrite was not detected in all column effluents due to biological equilbrium between nitro semonas and nitrobacter Average removals of ammonium nitrogen in each column after the lapse of 30days were the following; ${\cdot}$ column A (ozone dose 3mg/L, EBCT 9.5min): about 100% ${\cdot}$ column B (ozone dose 1mg/L, EBCT 9.5min): 91% ${\cdot}$ column C (ozone dose 3mg/L, EBCT 14.2min): about 100% ${\cdot}$ column D (ozone dose 0mg/L, EBCT 9.5min): 53% Though column A and C reached nitrification of about 100%, column C (longer EBCT than column A) was more stable than column A. (3) After backwash, nitrification reached steady state within 5 to 8 hours. Therefore, nitrification was not greatly affected by backwash. (4) According to the nitrification capacity in depth of column A, C, where 100% nitrification occured. LAS was removed within 20cm, while ammonium nitrogen required more depth to be removed by nitrification.

• Journal of Life Science
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• v.14 no.1
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• pp.167-173
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• 2004

The optimal conditions for the continuous production of $\gamma$-aminobutyric acid by immobilization of Lactobacillus brevis BH-21 using column type reactor were investigated. The optimal conditions of operation were 2.2 mm diameter bead of 3.0% sodium alginate at 10 mL/h of substrate feeding rate. Continuous production by immobililzed cells showed the highest productivity with replacement of fresh medium in every 48h for fourth fermentatoin cycle following the rendition of $\gamma$-aminobutyric acid productivity. A productivity of $\gamma$-aminobutyric acid could be obtained for 25 days by continuous column type reactor under optimal conditions.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.582-587
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• 2011

Holdup characteristics of bubble, wake and continuous liquid phases were investigated in bubble columns with viscous liquid media. Effects of column diameter(0.051, 0.076, 0.102 and 0.152 m ID), gas velocity($U_G$=0.02~0.16 m/s) and liquid viscosity(${\mu}_L$=0.001~0.050 $Pa{\cdot}s$) of continuous liquid media on the holdups of bubble, wake and continuous liquid phases were discussed. The three phase such as bubble, wake and continuous liquid phases were classified successfully by adapting the dual electrical resistivity probe method. Compressed filtered air and water or aqueous solutions of CMC(Carboxy Methyl Cellulose) were used as a gas and a liquid phase, respectively. To detect the wake as well as bubble phases in the bubble column continuously, a data acquisition system(DT 2805 Lab Card) with personal computer was used. The analog signals obtained from the probe circuit were processed to produce the digital data, from which the wake phase was detected behind the multi-bubbles as well as single bubbles rising in the bubble columns. The holdup of bubble and wake phases decreased but that of continuous liquid media increased, with an increase in the column diameter or liquid viscosity. However, the holdup of bubble and wake phases increased but that of continuous media decreased with an increase in the gas velocity. The holdup ratio of wake to wake to bubble phase decreased with an increase in the column diameter or gas velocity, however, increased with an increase in the viscosity of con-tinuous liquid media. The holdups of bubble, wake and continuous liquid media could be correlated in terms of operating variables within this experimental conditions as: ${\varepsilon}_B=0.043D^{-0.18}U_G^{0.56}{\mu}_L^{-0.13}$, ${\varepsilon}_W=0.003D^{-0.85}U_G^{0.46}{\mu}_L^{-0.10}$, ${\varepsilon}_C=1.179D^{0.09}U_G^{-0.13}{\mu}_L^{0.04}$.

• Steel and Composite Structures
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• v.37 no.3
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• pp.307-321
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• 2020

The slim-floor solution provides an efficient alternative to the classic slab-over-beam configuration due to architectural and structural benefits. Two deficiencies can be identified in the current state-of-art: (i) the technique is limited to nonseismic applications and (ii) the lack of information on moment-resisting slim-floor beam-to-column joints. In the seismic design of framed structures, continuous beam-to-column joints are required for plastic hinges to form at the ends of the beams. The present paper proposes a slim-floor technical solution capable of expanding the current application of slim-floor joints to seismic-resistant composite construction. The proposed solution relies on a moment-resisting connection with a thick end-plate and large-diameter bolts, which are used to fulfill the required strength and stiffness characteristics of continuous connections, while maintaining a reduced height of the configuration. Considering the proposed novel solution and the variety of parameters that could affect the behavior of the joint, experimental and numerical validations are compulsory. Consequently, the current paper presents the experimental and numerical investigation of two slim-floor beam-to-column joint assemblies. The results are discussed in terms of moment-rotation curves, available rotational capacity and failure modes. The study focuses on developing reliable slim-floor beam joints that are applicable to steel building frame structures located in seismic regions.

• Journal of Environmental Science International
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• v.7 no.1
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• pp.89-95
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• 1998

Ion exchange performance to remove nitrate in water was studied using commercially available strong base anion exchange resin of Cl- type in the batch and continuous column reactors. The performance was tested using the effluent concentration histories for continuous column or equilibrium conquilibrium between resin and solution. Anion exchange resin used in this study was more effective than activated carbon or zeolite for nitrate removal. With large resin amount or low initial concentration, nitrate removal characteristics for a typical gel-type resin was Increased. On considering the relation between the breakthrough capacity and nitrate concentration of the influent, the use of anion exchange resin were suitable for the hi선or order water treatment. The nitrate removal of above 90% could be possible until the effluent of above 650 BV was passed to the column. Thus, the commercially available strong base anion exchange resin of $Cl^-$ type used in thins study could be effectively used as economic material for treatment of the groundwater. The breakthrough curves showed the sequence of resin selectivity as $SO_4^{2-}$ > $NO_3$ > $NO^{2-}$ > $HCO_3^-$. The results of this study could be scaled up and used as a design tool for the water purification system of the real groundwater and surface water treatment processes.

• KSBB Journal
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• v.11 no.5
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• pp.524-528
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• 1996

Bacterial degradation of 4-chloro-2-methylphenoxyacetic acid (MCPA) was studied in column reactors under conditions approximating a fluidized bed system, with granular activated carbon (GAC) as a support matrix. A mixed bacterial culture of MCPA-degrading bacteria was used as an inoculum to develop a biofilm on GAC. Initially, adsorption of MCPA by GAC and blofilm formation on GAC were examined. MCPA degradation was evaluated with a batch and continuous mode of operation of the GAC fixed-film column reactors. In the batch operations, complete degradation of MCPA was achieved during the incubation period. Partial degradation of MCPA occurred in the continuous operations and MCPA degradation was dependent on the feeding rate of MCPA solution.