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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society for Atmospheric Environment
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Korean Society for Atmospheric Environment
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Volume & Issues
Volume 18, Issue 6 - Dec 2002
Volume 18, Issue 5 - Oct 2002
Volume 18, Issue 4 - Aug 2002
Volume 18, Issue 3 - Jun 2002
Volume 18, Issue 2 - Apr 2002
Volume 18, Issue 1 - Feb 2002
Volume 8, Issue 6 - 00 2002
Volume 8, Issue 5 - 00 2002
Volume 8, Issue 2 - 00 2002
Volume 18, Issue E4 - 00 2002
Volume 18, Issue E3 - 00 2002
Volume 18, Issue E2 - 00 2002
Volume 18, Issue E1 - 00 2002
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Application of the Cake-Filtration Theory to Analyze the Permeate Performance in Poly(vinylbenzyl chloride)-Filled Micro filtration Membrane
Park, Young G. ; 변홍식 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 7~537
In order to experimentally analyze the permeate performance of a membrane synthesized by a pore-filling technique, microfiltration experiments are conducted using pretreated wastewater having high alkality. The conventional cake filtration theory was also used in order to determine the permeability and the resistance of the cake-layer in the membrane. From the experimental results, the hydraulic permeability by diffusive-convective transport was measured as a function of the amount of gellation in the pores, which was enhanced by more than 70% in comparison with the nascent membrane. The transmembrane pressure (TMP) was also reduced by 80% in the newly developed membrane as the ion-exchange capacity increased. The resistance (Rm) in the membrane was reduced by 35% in comparison with the nascent membrane. The gellation of the pore-filled membrane was synthesized by impregnating the pores with a monomer solution, i.e., a crosslinker, followed by polymerization with piperizine. An appreciable enhancement of the permeate flux in the pore-filled membrane was noted using pre-treated wastewater under 10 kgf/cm(2).
Comparison of Theoretically and Experimentally Determined Simulated Coal Syngas Turbulent Jet Flame Lengths
조명철 ; 김현택 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 11~578
The current paper describes the results of a systematic experimental study of the visible lengths of coal-derived syngas jet diffusion flames. A combustion system was designed to produce a uniform swirl diffusion flame, for comprehending the flame characteristics of coal-derived fuel. To determine the flame length characteristics of the flame, the nozzle diameter of the lab-scale combustor was varied at 1.23, 1.96, and 2.95 mm and the flame length of each condition was studied. The fuel gases used were various compositions of CO and H2, simulating the composition of coal synthetic gases. The flame length characteristics of the simulated coal synthetic gases with different compositions were examined. The results of the experiment were compared with the characteristics of a pure methane flame using the dimensionless flame length, L*. The calculated flame lengths were slightly lower than the actual measured flame lengths, and the flame length values for both cases were well matched with values obtained at the corresponding experimental conditions. Accordingly, within the experimental parameters of the current investigation, the flame length was mainly determined by the nozzle type of the combustor.
Antibacterial Copolymer Synthesized from Methyl Methacrylate and 3-Pentachlorophenyloxy-1-propene
이윤식 ; 박광영 ; 김채건 ; 김완영 ; 변윤섭 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 11~591
Methyl methacrylate (MMA) was copolymerized with either pentachlorophenyl acrylate (PCA) or 3-pentachlorophenyloxy-1-propene (POP) to obtain poly(MMA-co-PCA) and poly(MMA-co-POP), respectively. Pentachlorophenol (PCP) was linked to poly(MMA-co-PCA) via ester bond while it was linked to poly(MMA-co-POP) via ether bond which is usually more resistant to hydrolysis. Poly(MMA-co-POP) underwent glass transition at a lower temperature (88 ℃) than poly(MMA-co-PCA) (115 ℃) due to less content of ester bonds. However, poly(NMA-co-POP) underwent thermal degradation at a slightly higher temperature (329 ℃) than poly(MMA-co-PCA) (284 ℃) probably due to more stable POP unit compared to PCA unit. The inhibition zone test indicated that the two different polymers were not significantly different in their antibacterial activities and they were bactericidal or bacteriostatic, depending on the bacterial species used.
Miscibility and Characterization of Poly(viny butyral)/Poly(methyl methacrylate) Blends
정환경 ; Don J. David ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 11~530
The current work describes the interaction of poly(methyl methacrylate) (PMMA) with random copolymer poly(vinyl butyrals)(PVBs) at various hydroxyl levels of residual vinyl alcohol (VA) in the PVB. The DMTA, SEM, and physical property data showed that blends with a generally lower residual VA content evidenced compatibility, while a blend of PVB containing about 23 wt% VA with PMMA at a ratio of 80:20, respectively, was thermodynamically miscible. The miscibility parameter model proved useful in examining potential regions of compatibility/miscibility and indicated that dispersive-polar interactions were mainly responsible for the miscibility of the amorphous phases.
Characterization of Hydrophobic Catalysts for Hydrogen Isotope Exchange Using a Recycle Reactor
조희수 ; 이한수 ; 김광락 ; 안도희 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 11~586
Several kinds of hydrophobic catalysts were developed to recover tritium from the DTO in CANDU reactors. A recycle reactor was built for the purpose of characterizing the developed hydrophobic catalysts. Two parameters, catalytic rate constant and pressure drop, of the hydrophobic catalysts called KC-1, KC-3, and KC-3S were measured at 100% relative humidity. The catalytic rate constants were measured at 60 ℃, and all the catalysts showed very high initial catalytic rate constants. The measured deactivation profile showed that catalytic rate constants of KC-1 and KC-3 were almost identical for 28 days. The deactivation profiles of the catalyst were represented in terins of catalytic rate constant, decontamination factor, and efficiency. The result showed that both KC-3 and KC-3S catalysts had a good exchange capacity for hydrogen isotopes and they could be used at the tritium removal facility that would be built at Wolsong nuclear power plants in the near future. The pressure drop across the catalyst bed was measured at three temperatures and various velocities. The result showed that the pressure drop caused by the catalyst bed was very small over the range of expected operation conditions.
-Tartaric acid-mediated Isolation of Optically Pure
-Penicillamine from Racemic Penicillamine
박선이 ; 이방숙 ; 남궁성건 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 15~515
Optical resolution of the unprotected racemic penicillamine was successfully achieved by L-tartaric acid in methanol/acetic acid. This process based on diastereomeric interaction gave the optically pure L-penicillamine in 80% yield.
Exergy Analysis of Cryogenic Air Separation Process for Generating Nitrogen
용평순 ; 문흥만 ; 이승철 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 15~499
A cryogenic air separation process that generates nitrogen has different process configurations depending on the utilization of either a cold heat supply method or a distillation method. Each method presents different initial investment costs, operating costs and energy efficiencies. Therefore, an accurate estimation of the energy efficiency as well as the cost is an important factor in selecting an appropriate process and in designing the most efficient equipment. Accordingly, the current study formulated criteria that can be applied to select the most efficient process. Processes using liquid nitrogen and an expansion turbine representing different cold heat supply methods were analyzed and evaluated to compare the exergy efficiency. In addition, the exergy efficiency of structure packing and sieve tray distillation method was also compared based on the experimental results.
Surface Modification with Waterborne Fluorinated Non-ionic Polyurethane Dispersion
조희성 ; 임철환 ; 노시태 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 17~524
Waterborne fluorinated non-ionic polyurethane dispersions (FNPUDs) were synthesized from tris(6-isocyanatohexyl) isocyanurate (TIHI), N-ethyl-N-2-hydroxylethyl-perfluorooctanesulfonamide (HFA), poly(oxyethylene glycol) (PEG) and 1,4-butanediol (BD). Waterborne polyurethane dispersion (PUD) was synthesized from isophorone diisocyanate (IPDI), poly(oxytetramethylene glycol) (PTMG), dimethylolpropionic acid (DMPA) and ethylenediamine (EDA). Fluorine PUD mixtures (FPMs) were prepared by blending the FNPUDs into the PUD. The particle size of the FNPUDs was measured by using dynamic light scattering (DLS), and the surface energy estimation and thermal property of the FPMs were studied by using a contact angle analyzer and differential scanning calorimetry (DSC). The particle size and glass transition temperature (Tg) of the FNPUDs tended to increase as the fluorine content in the FNPUD increased. When the fluorine content was 0.087 wt%, based on the total solid content, the surface energies of the FPMs exhibited the lowest values. In the same fluorine content in the FPMs, the surface energies of FPMs containing a higher fluorine content in the FNPUD exhibited a lower surface energy than those containing a lower fluorine content in the FNPUD. The thermal properties of the FPMs were found to be similar to the pure PUD. Accordingly, these results indicate that the phase separation and thermal behavior of the FNPUDs did not appear due to the compatibility of the polyether type PUD and the FNPUDs.
Acetic Acid Production Using Xylose and Corn Steep Liquor by thermoaceticum Strain
김준석 ; 김현준 ; 오경근 ; 김영수 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 17~519
Acetic acid production from xylose by Clostridium thermoaceticum (ATCC 49707) requires adaptation of the strain to xylose medium. It preferentially consumes xylose over glucose using a mixture of glucose and xylose as a carbon source. The initial concentration of xylose in the medium affects the final concentration and the yield of acetic acid. Batch fermentation of 20 g/L of xylose with 5 g/L of yeast extract (YE) as a nitrogen source results a maximum acetate concentration of 15.2 g/L and yield of 0.76 g acid/g xylose. Corn steep liquor (CSL) is a good substitute for yeast. extract and results in similar fermentation profiles. The organism consumes fructose, xylose and glucose when from a mixture of sugars in batch fermentation. Arabinose, mannose and galactose are consumed only slightly. This organism loses viability upon fed-batch operation even with supplementation of all the required nutrients. In fed-batch fermentation with CSL supplementation, D-xylulose (an intermediate in the xylose metabolic pathway) accumulates in large quantities.
Flow and Heat Transfer Characteristics of Drag Reduction Additives in District Heating and Coolings System
윤석만 ; 김남진 ; 김종보 ; 허명기 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 19~564
In the present investigation, the effects of polymer additives in district heating and cooling system to produce significant reductions in drag and heat transfer reduction are having observed. It is found that comparing with well-known polyacrylamide, copolymer additives are more effective and reliable in obtaining maximum drag reduction, and there also exist optimal conditions for mixing ratio of polymers, and with surfactants. It is found that the ice slurry system gives less pressure drops compared with chilled water system with ice fractions. Since the ice slurry system has an advantage due to its heat capacity, it can be a very effective method for district cooling system. Consequently, great energy savings in the system and the competitiveness of the district heating and cooling system will be greatly increased consequently.
Catalytic Combustion of Benzene over Copper Oxide Supported on
Prepared by Sol-Gel Method
이광호 ; 이만식 ; 이건대 ; 김영호 ; 홍성수 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 19~572
Catalytic combustion of benzene was carried out using TiO2 supported copper oxides. TiO2 catalysts were prepared by sol-gel method from the titanium isopropoxide. All catalysts were characterized by XRD, ESR and FT-Raman spectroscopy. The catalytic activity of CuOx/TiO2 catalysts according to preparation conditions was also examined. The major phase of all the prepared particles was anatase, while the rutile peak was observed above 700 ℃. From the ESR and FT-Raman results, the CuO dispersed on the TiO2 surface acts as an active site of CuOx/TiO2 catalysts on the oxidative decomposition of benzene. The catalytic activity was shown almost similar activity on benzene conversion regardless of R ratio. In addition, the CuOx supported on TiO2 calcined at 400 ℃ showed the highest activity and the conversion reached almost 100% at 270 ℃. The catalytic activity gradually increased with an increase of Cu loading on TiO2. When Cu loading reached 5.5 wt.%, the total conversion temperature was lowered to 300 ℃.
Performance of Water-repellent Treated Wooden Bath by Contact Angle Analysis
이영구 ; 김헌종 ; 박희준 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 23~506
This study is designed to measure the durability of a water-repellent, which is used for treating a wooden bath or bathroom exposed to soapy water. Sometimes, the wooden bath is exposed to hot and alkaline water for long periods of time. The durability of the water-repellent is measured by examining the changes surface free energy by contact angle, chemical variation by FT-IR and surface morphology by SEM, hot water temperatures and varying lengths of exposure to alkaline conditions. For the specimen treated by water-repellent, according to the result obtained from contact angle analysis, the surface of sample was found to be non-polar. After dipping in alkaline liquid, the polarity of the surface of the sample increased with increasing dipping time. Therefore, the contact angle for diiodomethane, being a non-polar liquid, exhibited little change. In the test using low alkaline conditions, the water-repellent showed no chemical or mechanical surface variation for 7 days at pH 7 and at a temperature of 80 ℃. In the test using highly alkaline conditions, the water-repellent exhibited a change in its surface polarity value at pH 13. However, in spite of the change in its surface polarity value, the durability of the water-repellent remained constant. The results of the FT-IR and SEM tests showed no variation in the chemical and mechanical properties of the surface of the water-repellent, which was subjected to low alkaline conditions for a period of 7 days and at a temperature of 80 ℃.
Resorcinol/Formaldehyde Aerogel Fine Powders with Nanopore Structure Prepared by Supercritical
이준영 ; 이경남 ; 이해준 ; 김정현 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 28~546
The preparation of resorcinol/formaldehyde (R/F) aerogel powders with nanopore structure by means of the supercritical CO2 drying technique has been studied. Spherical morphology of R/F aerogel powders was confirmed by scanning electron microscopy. The sizes of these fine powders ranged from 4 micrometer to a few hundred micrometers. The particle sizes were controlled by the emulsification conditions. The structure of R/F aerogel powder was revealed by FT-IR and BET analysis. The surface area and pore size of R/F aerogel powders with a fibrous-like network are in the range of 400 m(2)/g to 800 m(2)/g and less than 100 nm, respectively.
Fabrication of Fluorescent Fiber Optic Sensor Using Fluorescein-labeled Calmodulin for the Determination of
양승태 ; 이창섭 ;
Journal of Korean Society for Atmospheric Environment, volume 8, issue 6, 2002, Pages 40~557
A fiber optic fluorosensor which shows a specific selectivity for Ca(2+) and Eu(3+) is developed. This sensor uses a fluorescein-labeled calmodulin (F-CaM) as a sensing reagent which forms a fluorescent chelate with Ca(2+) and Eu(3+). A dialysis membrane is employed to entrap 0.50 mM EGTA/5.0 mM Tris-HCl buffer solution (pH 7.0) with F-CaM at the common end of a bifurcated fiber optic bundle. The sensing mechanism of this sensor is based on the change in fluorescence intensity of metal-calmodulin complexes where CaM undergoes a conformational change upon binding with Ca(2+) and Eu(3+). The resulting change in fluorescence signal can be related to the concentration of Ca(2+) and Eu(3+) and used for determination of those metal ions. The detection limits of Ca(2+) and Eu(3+) are measured to be 5 X 10(-8) M and 1.0 X 10(-15) M, respectively. The addition of EGTA to the sample buffer solution minimized the effect of background calcium. The sensor showed the best response to F-CaM in pH 7.0 Tris-HCl buffer. The dialysis membrane of the higher molecular weight cutoff showed a better condition on the response characteristics of the sensor. The interference effects of Mg(2+), K(+) and Na(+) were not significant to the sensor signal of Ca(2+) and Eu(3+).