• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.109-115
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• 2004

Hydrocyclone has been widely used for the solid-liquid separation in many industrial sites because of its comparatively preferable applications that can be applied to wide-range particle sizes. If seawater with impurities flows through pumps or heat exchanger, it might cause an decrease in efficiency of cooling system. In this paper, we have suggested some methods of separating impurities from seawater in the cooling system by using a Hydrocyclone. The effects of design factors as solid concentration, cyclone inlet pressure, flow rate and diameter of underflow on the separating performance of the Hydrocyclone were investigated The results from this study are summarized as follows: 1) In proportion to the decrease of solid concentration, the efficiency of solid-liquid separation is improved 2) According as the cyclone inlet pressure increases the efficiency of separation is improved Conclusively, this research suggested that the Hydrocyclone will be used as a pre-treatment system of cooling water in machines, and eventually prevent unexpected accidents in engine systems.

• Analytical Science and Technology
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• v.30 no.4
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• pp.174-181
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• 2017

Bio-liquid is a liquid by-product of the hydrothermal carbonization (HTC) reaction, converting wet biomass into solid hydrochar, bio-liquid, and bio-gas. Since bio-liquid contains various compounds, it requires efficient sampling method to extract the target compounds from bio-liquid. In this research, fatty acid methyl ester (FAME) in bio-liquid was extracted based on hollow fiber supported liquid phase microextraction (HF-LPME) and determined by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography/Mass Spectrometry (GC/MS). The well-known major components of biodiesel, including methyl myristate, palmitate, methyl palmitoleate, methyl stearate, methyl oleate, and methyl linoleate had been selected as standard materials for FAME analysis using HF-LPME. Physicochemical properties of bio-liquid was measured that the acidity was 3.30 (${\pm}0.01$) and the moisture content was 100.84 (${\pm}3.02$)%. The optimization of HF-LPME method had been investigated by varying the experimental parameters such as extraction solvent, extraction time, stirring speed, and the length of HF at the fixed concentration of NaCl salt. As a result, optimal conditions of HF-LPME for FAMEs were; n-octanol for extraction solvent, 30 min for extraction time, 1200 rpm for stirring speed, 20 mm for the HF length, and 0.5 w/v% for the concentration of NaCl. Validation of HF-LPME was performed with limit of detection (LOD), limit of quantitation (LOQ), dynamic range, reproducibility, and recovery. The results obtained from this study indicated that HF-LPME was suitable for the preconcentration method and the quantitative analysis to characterize FAMEs in bio-liquid generated from food waste via HTC reaction.

• KSBB Journal
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• v.20 no.4
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• pp.317-322
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• 2005

Various recovery methods were investigated to maximize hemicellulose recovery from lignocellulosic material hydrolyzed by pure water. The pretreatment conditions of water hydrolysis were $170\~180^{\circ}C$ and 1 hour of reaction time. The percentage of hemicellulose solubilized increased as the temperature increased from 170 to $180^{\circ}C$. However, significant decomposition of sugar was observed at temperature of $180^{\circ}C$. From the results of water hydrolysis, the total amount of glucan in solid residue and liquid hydrolyzate was close to the total glucan in the original biomass. For hemicellulose, however, there was a significant difference between both contents. To prove this difference, various recovery methods were proposed. From the total sugar accountability (sugar in liquid + sugar in solid), it was confirmed that hemicellulose recovery in the hydrolyzate was increased if the product including both hydrolyzate and solid residue was physically stimulated by such as heating and ultrasound irradiation. This indicated that, in commercial scale processes that much bigger substrate sizes are used and a sufficient amount of leaching solvent can not be used after pretreatment, a significant amount of oligomers could be trapped in the solid matrix.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.4
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• pp.285-296
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• 2005

In order to reduce the compression power and to use the overall energy contained in LNG effectively, a combined cycle is devised and simulated. The combined cycle is composed of two cycles; one is an open cycle of liquid/solid carbon dioxide production cycle utilizing LNG cold energy in $CO_2$ condenser and the other is a closed cycle gas turbine which supplies power to the $CO_2$ cycle, utilizes LNG cold energy for lowering the compressor inlet temperature, and uses the heating value of LNG at the burner. The power consumed for the $CO_2$ cycle is investigated in terms of a production ratio of solid $CO_2$. The present study shows that much reduction in both $CO_2$ compression power (only $35\%$ of power used in conventional dry ice production cycle) and $CO_2$ condenser pressure could be achieved by utilizing LNG cold energy and that high cycle efficiency ($55.3\%$ at maximum power condition) in the gas turbine could be accomplished with the adoption of compressor inlet cooling and regenerator. Exergy analysis shows that irreversibility in the combined cycle increases linearly as a production ratio of solid $CO_2$ increases and most of the irreversibility occurs in the condenser and the heat exchanger for compressor inlet cooling. Hence, incoming LNG cold energy to the above components should be used more effectively.

• Journal of Ocean Engineering and Technology
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• v.25 no.5
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• pp.15-20
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• 2011

This study carried out a series of experiments involving impact tests (Drop Weight type & Charpy type with a standard specimen and newly designed I-type specimen), hardness tests, and fracture surface observations of French-made roll shell steel (F), abnormal roll shell steel (M), reheated roll shell steel (R), and S25C steel under heat treatment conditiAn experimental study was carried out to study the solid-liquid mixture upward hydraulic transport of solid particles in vertical and inclined annuli with a rotating inner cylinder. The lift forces acting on a fluidized particle play a central role in many important applications such as the removal of drill cuttings in horizontal drill holes, sand transport in fractured reservoirs, sediment transport, the cleaning of particles from surfaces, etc. In this study a clear acrylic pipe was used to observe the movement of solid particles. Annular velocities varied from 0.4 to 1.2 m/s. The effect of the annulus inclination and drill pipe rotation on the carrying capacity of a drilling fluid, particle rising velocity, and pressure drop in a slim hole annulus were measured for fully-developed flows of water and aqueous solutions of CMC (sodium carboxymethyl cellulose) and bentonite. The rotation of the inner cylinder was efficient at carrying particles to some degree. For a higher particle volume concentration, the hydraulic pressure loss of the mixture flow increased because of the friction between the wall and solids or between solids.

• KSBB Journal
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• v.8 no.4
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• pp.382-389
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• 1993

In order to elucidate the effect of acetate ion on the growth of Escherichia coli, flask and fermentor cultures were performed using M9 and LB media. Acetic acid was secreted at a higher rate under the conditions of high glucose concentration as well as of richer medium, i. e., LB broth. The pH in flask culture could not be controlled as i fermentor and pH decreased with the formation of acetic acid. The inhibition effect of acetic acid was pronounced at a lower pH, and the effective inhibitory concentrations of acetic acid were 2.0g/l for LB flask culture, 4.0g/l for M9 flask culture, and 8.0g/l for M9 fermentor culture. Dialysis flask culture was designed to slowly provide E coli cells with glucose. Solid LB agar was layered under LB liquid medium with the variation of agar concentration and solid volume, The increase in the solid portion in the total volume(agar＋liquid) resulted in the increase of the final cell concentration. This can be ascribed to the fact that the larger solid phase behaves like a larger reservoir for glucose and controls the growth of E. coli with a controlled rate.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.6
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• pp.50-59
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• 2014

This experiment was performed in order to study the relationship between physical properties of soil and the growth characteristics of Sedum reflexum. A correlation analysis and multiple regression analysis were performed using SPSS Ver 19.0 for Windows. The multiple regression analysis results of soil physical properties and growth characteristics were as follows. The regression equation: The length=$.993-14.070^*$(soil bulk density)+$.233^*$(solid phase)+$.038^*$(liquid phase)+$.068^*$(permeability). The significance of soil bulk density and solid phase was great. The width=$2.931-33.925^*$(soil bulk density)+$.566^*$(solid phase)+$.206^*$(liquid phase)+$.027^*$(permeability). The significance of soil bulk density and solid phase was great. The wet weight and dry weight of the upper and lower and soil physical properties did not have a direct relationship.

• Tribology and Lubricants
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• v.37 no.2
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• pp.71-76
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• 2021

As opposed to using fossil fuels, we need to use eco-friendly resources such as sunlight, raindrops and wind to produce electricity and combat environmental pollution. A triboelectric nanogenerator (TENG) is a device that converts mechanical energy into electricity by inducing repetitive contact and separation of two dissimilar materials. During the contact and separation processes, electron flow occurs owing to a change in electric potential of the contacting surface caused by contact electrification and electrostatic induction mechanisms. A solid-solid contact TENG is widely known, but it is possible to generate electricity via liquid-solid contact. Therefore, by designing a hydrophobic TENG, we can gather electricity from raindrop energy in a feasible manner. To fabricate the superhydrophobic surface of TENGs, we employ a dip coating technique to synthesize an octadecylamine (ODA)- and polydimethylsiloxane (PDMS)-based coating on polyethylene terephthalate (PET). The synthesized coating exhibits superhydrophobicity with a contact angle greater than 150° and generates a current of 2.2 ㎂/L while water droplets fall onto it continuously. Hence, we prepare a box-type TENG, with the ODA/PDMS coating deposited on the inside, and place a 1.5 mL water droplet into it. Resultantly, we confirm that the induced vibration causes continuous impacts between the ODA/PDMS coating and the water, generating approximately 100 pA for each impact.

• Advances in nano research
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• v.10 no.3
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• pp.295-312
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• 2021

A new ionic liquid functionalized magnetic silica nanoparticle was synthesized and characterized and tested as an adsorbent. The adsorbent was used for magnetic solid phase extraction on ICP-MS method. Simultaneous determination of precious metal Au has been addressed. The method is simple and fast and has been applied to standard water and surface water analysis. A new method for separation/analysis of trace precious metal Au by Magnetron Solid Phase Extraction (MSPE) combined with ICP-MS. The element to be tested is rapidly adsorbed on CoFe2O4@SiO2@[BMIM]PF6 composite nano-adsorbent and eluted with thiourea. The method has a preconcentration factor of 9.5-fold. This method has been successfully applied to the determination of gold in actual water samples. Hydrophobic Ionic Liquids (ILs) 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6) coated CoFe2O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (CoFe2O4@SiO2@ILs) and establish a new method of MSPE coupled with inductively coupled plasma mass spectrometry for separation/analysis of trace gold. The results showed that trace gold was adsorbed rapidly by CoFe2O4@SiO2@[BMIM]PF6 and eluanted by thiourea. Under the optimal conditions, preconcentration factor of the proposed method was 9.5-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.01~1000.00 ng·mL-1, 0.001 ng·mL-1, 0.9990 and 3.4% (n = 11, c = 4.5 ng·mL-1). The CoFe2O4@SiO2 nanoparticles could be used repeatedly for 8 times. This proposed method has been successfully applied to the determination of trace gold in water samples.

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.459-464
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• 2009

Gas-liquid mass transfer characteristics were investigated in pressurized three-phase slurry bubble columns with variation of column diameter. Effects of gas velocity, operating pressure, liquid viscosity, solid content in the slurry phase and column diameter on the gas-liquid volumetric mass transfer coefficient($k_La$) were determined. The effects of operating variables on the mass transfer coefficient tended to change with variation of column diameter. The mass transfer coefficient increased with increasing gas velocity or operating pressure but decreased with increasing column diameter, liquid viscosity or solid concentration in the slurry phase. The increase trend of $k_La$ value with increasing gas velocity and the decrease trend of $k_La$ value with increasing liquid viscosity, tended to decrease gradually with increasing column diameter. However, the effects of operating pressure and solid concentration in the slurry phase on the $k_La$ value did not change considerably with variation of column diameter. The values of $k_La$ were well correlated with operating variables with in this experimental conditions as $k_La=0.02D^{-0.26}U_G^{0.28}P^{0.43}{\mu}_L^{-0.04}S_c^{-0.35}$.