• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.456-459
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• 2000

A pilot scale experiment was performed for a year to develop a two-phase anaerobic process for piggery wastewater treatment (COD: 6,000mg/L, BOD: 4,000mg/L, SS: 500mg/L, pH 8.4, alkalinity 6,000mg/L). The acidogenic reactor had a total volume of 3㎥, and the methanogenic reactor, an anaerobic up-flow sludge filter, combining a filter and a sludge bed, was also of total volume 3㎥(1.5㎥ of upper packing material). Temperatures of the acidogenic and methanogenic reactors kept at 20$^{\circ}C$ and 35$^{\circ}C$, respectively. When the pH of the acidogenic reactor was controlled at 6.0-7.0 with HCl, the COD removal efficiency increased from 50 to 80% over a period of six months, and as a result, the COD of the final effluent fell in the range of 1,000-1,500 mg/L. BOD removal efficiency over the same period was above 90%, and 300 to 400 mg/L was maintained in the final effluent. The average SS in the final effluent was 270 mg/L. The methane production was 0.32㎥ CH$_4$/kg COD(sub)removed and methane content of the methanogenic reactor was high value at 80-90%. When the pH of the acidogenic reactor was not controlled over the final two months, the pH reached 8.2 and acid conversion decreased compared with that of pH controlled, while COD removal was similar to the pH controlled operation. Without pH control, the methane content in the gas from methanogenic reactor improved to 90%, compared to 80% with pH control.

• Korean Journal of Veterinary Research
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• v.37 no.1
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• pp.195-202
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• 1997

A method for the isolation by matrix solid phase dispersion method and liquid chromatographic determination of enrofloxacin and ciprofloxacin in pork muscle tissue is presented. Blank or enrofloxacin and ciprofloxacin spiked samples(0.5g) containing 0.05g oxalic acid were blended with $C_{18}$(octadecylsilyl derivatized silica) packing material. After homogenization, $C_{18}$/muscle tissue matrix was transferred to glass column made from 10ml glass syringe and filter paper, and compressed to 4~4.5ml volume. A column was washed with 8ml of hexane and dried under vacuum. Interfering materials were removed by ethylacetate 8ml and dried, following which enrofloxacin and ciprofloxacin were eluted with 8ml of methanal under gravity. The eluate containing enrofloxacin and ciprofloxacin wase free from interfering compound when analysed by HPLC with UV detection at 278nm. Enrofloxacin and ciprofloxacin showed linear response with UV detector at the range of $0.05{\sim}1.0{\mu}g/ml$ and eluted within 5ml elution volume of methanol from the matrix. Fortified sample containing 0.05g oxalic acid represented more good recoveries than that of control sample. Average percentages of enrofloxacin and ciprofloxacin were $93.30{\pm}4.56%$ and $91.84{\pm}4.17%$, respectively, for the concentration range(0.05, 0.1, 0.25, 0.5 and $0.75{\mu}g/g$). The interassay variability of enrofloxacin was $6.02{\pm}5.33%$ with an intra-assay variability of 4.89% and $6.75{\pm}2.68%$ with 4.54% for ciprofloxacin. Detection limit of enrofloxacin and ciprofloxacin was $0.030{\mu}g/g$ in the spiked sample.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.242-249
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• 1998

The engineering aspect of water treatment processes in the recirculating aquaculture system was studied. To recycle the water in the aquaculture system, a wastewater treatment process was required to maintain high water quality for the growth and health of the cultured fish. In this study, three different biofilm processes were used to reduce the concentration of organic matters and ammonia from the recirculating water - two phase fluidized bed, three phase fluidized bed, and trickling filter. The objectives of this research were to evaluate the optimum treatment conditions of the biofilm processes for the recirculating aquaculture system, and thereby reduce the volume of biofilm processes, which are commonly used for the recycle water treatment processes for aquaculture. The result of this study showed that the removal efficiency of organic matters by trickling filter was found to be lower than that of the fluidized bed. In the trickling filter system, anthracite showed better organic removal efficiency than crushed stone as a media. In the two phase fluidized bed, the maximum removal efficiency of either organics or ammonia was obtained when both the packing rate of media was maintained to $40\%$ of total reactor depth excepting sediment zone and the bed expansion rate was maintained to $100\%$. When 100 tilapia (Oreochromis niloticus) of each average 200g was reared, the pollutant production rate was 0.07g $NH_4\;^+-N/kg$ fish/day and 0.06g P04-3-P/kg fish/day, and sludge production rate was 0.39 g SS/kg fish/day. In the two phase and three phase fluidized bed, the volume of water treatment tank could be calculated from an empirical equation by using the relationship between the influent COD to $NH_4\;^+-N$ ratio (C/N, -), media concentration (Cm, g/L), influent ammonia nitrogen concentration (Ni, mg/L), effluent ammonia nitrogen concentration (Ne, mg/L), bed expansion rate $(E,\;\%)$, and influent flowrate $(Q,\;m^3/hr)$. The empirical equation from this study is $$V_2\;=\;10^{3.1279}\;C/N^{3.5461}\;C_m\;^{-3.7473}\;N_i\;^{4.6477}\;E^{0.0326}\;N_e\;^{-0..8849}\;Q\;(Two\;Phase\;FB) V_3\;=\;10^{11.7507}\;C/N^{-1.2330}\;C_m\;^{-6.5715}\;N_i\;^{1.5091}\;N_e\;^{-1.8489}\;Q (Three\;Phase\;FB)$$

• Journal of Food Hygiene and Safety
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• v.12 no.2
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• pp.117-124
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• 1997

A simple, rapid and simultaneous analytical method is described for the detection of Sulfonamide and Tetracycline residues, i.e., Sulfamerazine (SMR), Sulfamethazine (SMT), Sulfamonomethoxine (SMM), Sulfadimethoxine (SDM), Sulfaquinoxaline (SQN), Oxytetracycline (OXY), Tetracycline (TC), Chlortetracycline (CTC). Blank control and sulfonamide and tetracycline fortified fish muscle samples (0.5 f) were blended with octadecylsilyl (C18, 40 ${\mu}{\textrm}{m}$, 21% load, 60$\AA$) derivatized silica packing material (2 g). Blended fish samples were washed with hexane, then, benzene and dichloromethace were used for the elution of tetracycline and sulfonamide were analyzed by HPLC. Correlation coefficients of standard curves for individual sulfonamide and tetracycline isolated from fortified samples were linear (0.9993$\pm$0.0003~0.9997$\pm$0.0003, 0.9493$\pm$0.078~0.9753$\pm$0.036), respectively. The average percentage recoveries of sulfonamide and tetracycline ranged as 80.86~96.52% to 85.88~92.23%, and 30.01~37.12% to 65.89~73.40%, for the concentration range (0.1~1.0 ppm) examined, respectively. Limit of detection for sulfonamide was 0.0012 ppm for SMR in Paralichthys Olivacleus and 0.0020 ppm for SMR, 0.015 ppm for SMM in Cyprinus Carpio. The applicability of this procedure is demonstrated by separation and detection of incurred tetracycline and sulfonamide residues in fish muscle tissue.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1258-1262
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• 2011

A new organogelator, L-Alanine dihydrazide derivative can self-assemble in various organic solvents and turned them into thermally reversible physical supramolecular organogels at extremely low concentrations (< 2 wt %). The gel-sol phase transition temperatures ($T_{GS}$) were determined as a function of gelator concentration and the corresponding enthalpies (${\Delta}H_g$) were extracted. Scanning electron microscopy (SEM) measurements revealed that the interspaces of fiber-like network structures were diminished with the increasing of the LMOG concentration. FT-IR spectroscopy studies revealed that hydrogen-bonding and hydrophobic interaction were the driving forces for the formation of the gels. Based on the data of XRD and molecular modeling, the possible packing modes for the formation of organogelator aggregates were proposed.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.3
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• pp.223-230
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• 2002

Titania photocatalytic oxidation reactors were studied to investigate degradation efficiencies of hydrocarbons. In general, it is well known phenomena that thin layered titania oxidizes most of hydrocarbons to carbon dioxide and water under UV light. In this study, degradation efficiencies were measured due to changes in reactor structures, UV sources, the number of titania coatings, and various hydrocarbon chemicals. It was proven that gas degradation efficiencies are related to such factors as UV transmittance of coating substance, collision area of surface, and gas flow rate. For packing type annular reactor, about 98% degradation efficiency was achieved for achieved for propylene of 500 ppm level at a flow rate of 100 ml/min. Several gases were also tested for double-coated titania thin film under the condition of continuous flow of 100 ml/min and 365 nm UV source. It was shown that degradation efficiencies were decreasing in the order: $C_3$ $H_{6}$, n-C$_4$ $H_{10}$, $C_2$ $H_4$, $C_2$ $H_2$, $C_{6}$ $H_{6}$ and $C_2$ $H_{6}$./. 6/./.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.65-68
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• 2011

The effects of column length and particle size on the efficiency of separation and characterization of phospholipids (PLs) are investigated using nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry (nLC-ESI-MS-MS). Since PLs are associated with cell proliferation, apoptosis, and signal transduction, it is of increasing interests in lipidomics to establish reliable analytical methods for the qualitative and quantitative profiling of PLs related to biomarker development in adult diseases. Due to the complexity of PLs, the preliminary separation of PLs is necessary prior to MS analysis. In this study, length of capillary column and the particle size of reversed phase ($C_{18}$) packing materials are varied to find a reliable condition for the high speed and high resolution separation using 8 PL standard mixtures. From experiments, it was found that a capillary column of nLC-ESI-MS-MS analysis for PL mixtures can be minimized to a 5 cm long pulled tip column packed with 3 ${\mu}m$ $C_{18}$ particles without losing resolution.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.39-45
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• 1997

Introduction : Polyimides are one of the most important classes of the high performance polymers due to their excellent electrical, thermal, and high-temperature mechanical properties. But their uses are limited because of their poor solubility. Most polyimide derivatives are processed in the form of polyamic acids, which are subsequently converted into the imide structures.Recently, it has been found that the soluble polyimides with large molecular weight sufficient to application. For enhancing processability, the majority of approaches have involved the following factors. As much as, the separation of the imide ring along the back-bone, that is to say, reducing the density of imide ring in the repeat structure. The introduction of bulky substituents along the back-bone, in order to enhance the free volume of main-chain. The incorporation of flexible or thermally stable linkages in the main-chain, reducing the packing force. The disruption of symmetry or recurrence regularity through copolymerization in order to reduce crystallnity.The objectives of this investigation are the synthesis and characterization of soluble polyimides as membrane materials by the single-step polymerization and the preparation of the asymmetric polyimide membrane by using phase inversion technique. In the present study, three series of polyimide derivatives are synthesized; H series is homopolyimides, A series is prepared from single dianhydride and two diamines, B series is yielded from two dianhydrides and a diamine. The dope solution was directly prepared from the PI solution via one step polymerization from monomers.

• Solar Energy
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• v.18 no.3
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• pp.95-105
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• 1998

In this study, basic design data which were required for development of highly efficient ice storage system with low temperature latent heat were experimentally obtained. The ice storage system considered in this study was the one that has been widly used in the developed country and called the ice-on-coil type. Using the system, the ice storage performance for various design parameters which were the flow direction and the inlet temperature of the secondary fluid was tested. In addition, the timewise variation of the interface profiles between the solid and the liquid were visualized, and the heat transfer characteristics of the Phase Change Material(PCM) in the ice storage tank were Investigated. During the freezing processes in the ice storage tank with several vertical tubes, decrease of the heat transfer area and the heat resistance of the ice layer made the increasing rate of ice packing factor(IPF) less. The total freezing energy for the upward flow of the secondary fluid was higher than that for the downward flow. The average ice storage efficiency for the upward flow of the secondary fluid was higher than that for the downward flow.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.488-492
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• 2009

Porous frit-bonded SiC ceramics were successfully prepared at a temperature as low as $800^{\circ}C$ from SiC, frit, and microbeads (glass or polymer). The effects of SiC starting particle size and microbead addition on microstructure, porosity, and flexural strength were investigated. The addition of hollow glass microbead improved the strength of frit-bonded SiC ceramics without the loss of porosity by acting additional binder phase between SiC grains. The 65 ${\mu}m$-sized SiC resulted in lower porosity and higher strength than 50 ${\mu}m$-sized SiC because of higher packing density. Typical flexural strengths of frit-bonded SiC were 23 MPa at 46% porosity and 19 MPa at 49% porosity.