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정의덕,강신원,박덕수,신학기,백우현 한국환경과학회 2000 한국환경과학회지 Vol.9 No.5
A study on the removal of Pb ion from Pb-contaminated soil was carried out, using ex-situ extraction process. Tartaric acid (TA) and iminodiacetic acid sodium salt (IDA) as a washing agent were evaluated as a function of concentration, reaction time, mixing ratio of washing agent and recycling of washing agent. TA showed a better extraction performance than IDA. The optimum washing condition of TA and IDA were in the ratio of 1 : 15 and 1 : 20 between soil and acid solution during 1 hr reaction. The total concentrations of Pb ion by TA and IDA at three repeated extraction, were 368.8 ppm and 267.5 ppm, respectively. The recovery of Pb ion from washing solution was achieved by adding calcium hydroxide and sodium sulfide, form the precipitation of lead hydroxide and lead sulfide, and optimum amounts of sodium sulfide and calcium hydroxide were 7 g/ℓ for the TA washing solution and 4 g/ℓ , 5 g/ℓ for the IDA washing solution, respectively. The efficiency of recycle for TA and IDA washing solution were 78.8%, 95.1% and 89.2%, 96.6%, at third extractions under Na_2S and Ca(OH)_2, respectively.
정의덕,강신원,백우현 한국환경과학회 2000 한국환경과학회지 Vol.9 No.1
A study on the remediation of heavily Fe ion contaminated soils from abandoned iron mine was carried out, using ex-situ extraction process. Also, oxalic acid as a complex agent was evaluated as a function of concentration, reaction time and mixing ratio of washing agent in order to evaluate Fe removability of the soil contaminated from the abandoned iron mine. Oxalic acid showed a better extraction performance than 0.1N-HCI, i.e., the concentrations of Fe ion extracted from the abandoned mine for the former at uncontrolled pH and the latter were 1,750 ppm and 1,079 ppm, respectively. The optimum washing condition of oxalic acid was in the ratio of 1:5 and 1:10 between soil and acid solution during 1 hr reaction. The total concentrations of Fe ion by oxalic acid and EDTA at three repeated extraction, were 4,554 ppm and 864 ppm, respectively. The recovery of Fe ions from washing solution was achieved, forming hydroxide precipitation and metal sulfide under excess of calcium hydroxide and sodium sulfide. In addition, the amounted of sodium sulfide and calcium hydroxide for the optimal recovery of Fe were 15g/ℓ and 5g/ℓ from the oxalic acid complexes, respectively.
백우현,정의덕,윤천기 한국환경과학회 2000 한국환경과학회지 Vol.9 No.5
The characteristics of Far-infrared rays mineral water(FIR water) have been compared to the tap water by means of relationship between FIR water and Nuclear Magnetic Resonance spectroscopy(NMR), FIR water and thermography, FIR water and velocity of blood, FIR-water and pH, FIR water and dissolved oxygen(DO), FIR water and Oxidation-Reduction Potential(ORP), using the development FIR water purification of grand prix system. From the experimental result are quite satisfactory when compared with the tap water. Also, the FIR water were evaluated to see if those are tasty and healthy using the Hashimoto's Mineral Balance Index. As a result, FIR-water was found as tasty and healthy.
Characteristics of Bubble Departure Frequency in a Low-Pressure Subcooled Boiling Flow
EUH, Dongjin,OZAR, Basar,HIBIKI, Takashi,ISHII, Mamoru,SONG, Chul-Hwa Atomic Energy Society of Japan 2010 Journal of nuclear science and technology Vol.47 No.7
<P>In order to measure the bubble departure frequency, a flow visualization system was set up on a vertical annulus test section with a heater rod by using a high-speed camera. In this study, we developed an efficient methodology of image processing for obtaining the bubble departure frequency data. Bubble nucleation was investigated under various thermal hydraulic conditions of water, which correspond to pressures from 167 to 346 kPa, mass fluxes from 214 to 1869 kg/m<SUP>2</SUP>s, heat fluxes from 61 to 238 kW/m<SUP>2</SUP>, and subcooling degrees from 7.5 to 23.4 K. The characteristics of bubble departure frequency were analyzed with the present data. The measured data was compared with models available in existing literature and a more plausible model was proposed.</P>
Euh, Kwangjun,Kang, Suk Bong Elsevier 2005 Materials science & engineering. properties, micro Vol.395 No.1
<P><B>Abstract</B></P><P>Aluminum (Al) matrix composites reinforced by SiC particulates (SiCp/Al) were fabricated by the atmospheric plasma spraying. The composite powder, as a feedstock for plasma spraying, was prepared by ball milling of pure Al powders with 55 vol.% SiC particles. The feedstock was deposited into a freestanding bulk composite sheet on a graphite substrate by atmospheric plasma spraying. As-sprayed composites had a great amount of porosity, which deteriorates the thermo-physical properties, especially the thermal conductivity. In order to reduce the porosity of the plasma-sprayed SiCp/Al composite sheets, rolling processes were carried out at the room and elevated temperature with the thickness reduction of about 20%. The thermal conductivities of the rolled composites were considerably enhanced with the decrease of the porosity in the composites, while the coefficients of thermal expansion (CTEs) of the composites were slightly affected by the rolling process.</P>
( Euh S. H. ) 강원대학교 농업생명과학연구원(구 농업과학연구소) 2017 강원 농업생명환경연구 Vol.29 No.2
Salt management technique in irrigated agriculture is becoming more important at the San Joaquin Valley of California as well as a number of other areas worldwide. Concentration and evaporation systems using solar energy are being developed in California for salt separation and recovery from drainage water. A model for the parabolic solar collector yielded accurate predictions relative to experimental data for fluid temperature changes and peak fluid temperatures. The peak temperature measured at 72°C was accurate when compared to the calculated results. The evaporation rate of the boiler was 82 kg/h from the model prediction and 76 kg/h from experimental measurements. The predicted efficiencies of the parabolic solar collector and the boiler were approximately 64% during the daytime and 70%, respectively. The cost per kg of dry salts based on net present worth (NPW) for the boiler prototype was $0.90 and $1.34 based on equivalent uniform annual cost (EUAC) with respect to 1 year, respectively, and the costs decreased as the boiler capacity increased.
Euh, D.J.,Kim, S.,Kim, B.D.,Park, W.M.,Kim, K.D.,Bae, J.H.,Lee, J.Y.,Yun, B.J. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.5
Multi-dimensional two-phase phenomena occur in many industrial applications, particularly in a nuclear reactor during steady operation or a transient period. Appropriate modeling of complicated behavior induced by a multi-dimensional flow is important for the reactor safety analysis results. SPACE, a safety analysis code for thermal hydraulic systems which is currently being developed, was designed to have the capacity of multi-dimensional two-phase thermo-dynamic phenomena induced in the various phases of a nuclear system. To validate the performance of SPACE, a two-dimensional two-phase flow test was performed with slab geometry of the test section having a scale of $1.43m{\times}1.43m{\times}0.11m$. The test section has three inlet and three outlet nozzles on the bottom and top gap walls, respectively, and two outlet nozzles installed directly on the surface of the slab. Various kinds of two-dimensional air/water flows were simulated by selecting combinations of the inlet and outlet nozzles. In this study, two-dimensional two-phase void fraction profiles were quantified by measuring the local gap impedance at 225 points. The flow conditions cover various flow regimes by controlling the flow rate at the inlet boundary. For each selected inlet and outlet nozzle combination, the water flow rate ranged from 2 to 20 kg/s, and the air flow rate ranged from 2.0 to 20 g/s, which corresponds to 0.4 to 4 m/s and 0.2 to 2.3 m/s of the superficial liquid and gas velocities based on the inlet port area, respectively.