• Proceedings of the Membrane Society of Korea Conference
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• 2004.07a
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• pp.57-68
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• 2004

A demonstrative operation of a membrane system with its caparity of 3,600m$^3$/d was carried out using reservoir water as raw water for the application of membrane filtration system to drinking water treatment. The operation was undertaken at a constant flux of 0.9 m$^3$/m$^2$/d for three months. Backwashing with NaClO of 3 ppm was allowed for 30 seconds every 20 minutes of filtration. Physical cleaning was introduced after 69 times of filtration/backwashing cycle with air-scrubbing and backwashing for 1 minute, and flushing for 2 minutes. In this study, water treatment performance was investigated compared with the existing rapid sand filtration process. The membrane system was operated with no significant problems during the test period. Higher water quality was obtained in the membrane filtration than in the rapid sand filtration in terms of particulate matters such as turbidity and microbes. Although the finished water of the membrane filtration contained slightly higher concentration in dissolved matters than that of the conventional one, it met the drinking water standard. The demonstrative operation showed that membrane filtration has a reliability in drinking water treatment. Researches should be needed on cost analysis through long-term operation and optimization of operation condition for further application.

• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.1-10
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• 2015

After the Fukushima Daiichi nuclear power plant (NPP) accident, new regulatory requirements were enforced in July 2013 and a backfit was required for all existing nuclear power plants. It is required to take measures to prevent severe accidents and mitigate their radiological consequences. The Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority (S/NRA/R) has been conducting numerical studies and experimental studies on relevant severe accident phenomena and countermeasures. This article highlights fission product (FP) release and hydrogen risk as two major areas. Relevant activities in the S/NRA/R are briefly introduced, as follows: 1. For FP release: Identifying the source terms and leak mechanisms is a key issue from the viewpoint of understanding the progression of accident phenomena and planning effective countermeasures that take into account vulnerabilities of containment under severe accident conditions. To resolve these issues, the activities focus on wet well venting, pool scrubbing, iodine chemistry (in-vessel and ex-vessel), containment failure mode, and treatment of radioactive liquid effluent. 2. For hydrogen risk: because of three incidents of hydrogen explosion in reactor buildings, a comprehensive reinforcement of the hydrogen risk management has been a high priority topic. Therefore, the activities in evaluation methods focus on hydrogen generation, hydrogen distribution, and hydrogen combustion.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.870-880
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• 2016

A steam generator tube rupture (SGTR) event with a stuck-open safety relief valve constitutes one of the most serious accident sequences in pressurized water reactors (PWRs) because it may create an open path for radioactive aerosol release into the environment. The release may be mitigated by the deposition of fission product particles on a steam generator's (SG's) dry tubes and structures or by scrubbing in the secondary coolant. However, the absence of empirical data, the complexity of the geometry, and the controlling processes have, until recently, made any quantification of retention difficult to justify. As a result, past risk assessment studies typically took little or no credit for aerosol retention in SGTR sequences. To provide these missing data, the Paul Scherrer Institute (PSI) initiated the Aerosol Trapping In Steam GeneraTor (ARTIST) Project, which aimed to thoroughly investigate various aspects of aerosol removal in the secondary side of a breached steam generator. Between 2003 and 2011, the PSI has led the ARTIST Project, which involved intense collaboration between nearly 20 international partners. This summary paper presents key findings of experimental and analytical work conducted at the PSI within the ARTIST program.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.3
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• pp.737-748
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• 2014

Increasing amounts of ships exhaust gases emitted worldwide forced the International Maritime Organization to issue some restricted maritime legislation for reducing the adverse environmental impacts arising from such emissions. Consequently, ships emission reduction became one of the technical and economical challenges that facing the ships, operators. The present paper addresses the different strategies that can be used to reduce those emissions, especially nitrogen oxides and sulfur oxides. The strategies included: applying reduction technologies onboard, using of alternative fuels, and follows one of fuel saving strategies. Using of selective catalytic reduction and sea water scrubbing appeared as the best reduction technologies onboard ships. Moreover, among the various proposed alternative fuels, natural gas, in its liquid state; has the priority to be used instead of conventional fuels. Applying one of those strategies is the matter of ship type and working area. As a numerical example, the proposed methods were investigated at a high-speed craft operating in the Red Sea area between Egypt and the Kingdom of Saudi Arabia. The results obtained are very satisfactory from the point of view of environment and economic issues, and reflected the importance of applying those strategies.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.45-46
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• 2013

Stabilization characteristics of highly $N_2$-diluted $CH_4-O_2$ flame in an axially two-section porous inert medium were experimentally investigated for its application to the waste gas scrubber in semiconductor manufacturing processes. The flame behaviors were observed with respect to the fuel and $N_2$ flow rates and the equivalence ratios. As a result, four kinds of flame behaviors such as stable, flashback crossing the interface, blowout and sudden extinction were observed. It was also found that there exists two flame regime divided by a critical fuel flow rate. In addition, the flame stability was discussed based on the $N_2$ index which means the abatement capacity of our combustor in scrubbing the waste gas from the semiconductor processes.

• Resources Recycling
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• v.14 no.5 s.67
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• pp.40-44
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• 2005

The purified phosphoric acid was recovered from crude phosphoric acid with high contents of aluminium and molybdenum ions to reuse the acid as an etchant. In this work, solvent extraction was applied to recover the phosphoric acid from crude phosphoric acid. Phosphate was used as an extractant. Further cleaning and removing processes on the recovered phosphoric acid were conducted to eliminate the metallic ion impurities in the acid. The process parameters were successfully optimized, so that the finally purified acid contained less than 1 ppm of aluminium and molybdenum ion.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.1
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• pp.41-49
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• 2011

The diffuser which is conventionally adapted to MBR, has problem that decreasing the cleaning effect of membrane module by inflexible air supply due to the occlusion of sludge from diffuser hole. To solve this problem, diffuser structure of submerged module should be improved to discharge sludge which is flow into the diffuser for prevent occlusion in the diffuser. In this study, the structure of the diffuser was reformed to open lower part for preclusion the blocking. And the outlet diameter of the diffuser was drawn through the condition for the depth of water and air rate, to prevent air-leak condition of improved diffuser. Moreover, application is evaluated by comparing test with occlusion effect of the conventional and improved diffuser. From the results, air-water boundary changes are steady with changes of water depth and it shows linear relation about air rate. By using this linear numerical formula, the height of diffuser's outlet can be decided. Also, it displays that it can prevent the occlusion effect during the comparing test. Hereafter, if this diffuser is applied to practical MBR process, the occlusion problem of diffuser will be disappeared.

• Journal of Convergence for Information Technology
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• v.9 no.6
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• pp.211-217
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• 2019

In this study, the change of skin condition was analyzed by skin analysis equipment using scrub cosmetics, and the morphological characteristics of microbead were observed by dermascope and scanning electron microscope. In the dermascope observation, during the process of cleansing, the microbeads attached to the skin existed in close contact with each other or dispersed. The skin after scrubbing was clean and smooth and the fine wrinkles between epidermal keratinocytes were reduced. In the scanning electron microscopic observation, the microbead surface did not have severe bending or rough surface. The skin moisture and oil content were higher than the scrub skin before the scrub, and there was no significant difference in the pH.

• Korean Journal of Metals and Materials
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• v.48 no.5
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• pp.430-435
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• 2010

Solvent extraction experiments of Rh(III) and Ir(IV) were performed on the HCl solution by using Alamine336 and TBP. The extraction percentage of Rh and Ir by Alamine336 was much higher than that by TBP. For the solvent extraction with Alamine336, the extraction percentage of Rh and Ir decreased with a HCl concentration. However, the extraction percentage of both metals by TBP was below 12% in our experimental range and increased with an increasing HCl concentration of up to 8 M. From the mixed solution of Ir with an excess SnCl$_{2}$, most of the tin was extracted by Alamine336 and TBP. However, the extraction percentage of Ir by Alamine336 was reduced and no iridium was extracted by TBP. The extraction behavior of Ir and Sn was investigated by scrubbing experiments on the loaded Ir with a SnCl$_{2}$ solution.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.486-492
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• 2022

Nitrogen oxides (NO_x; NO and NO₂) are major air pollutants and can cause harmful effects on the human body. Electron Beam Flue Gas Treatment (EBFGT) is a technology that generates electrons with an energy of 0.5-1 MeV using electron accelerators and effectively processes exhaust gases. In this study, NO_x was removed using an electron beam accelerator with spraying additives (NaOH and NH₄OH). NO and NO₂ were 100% and more than 94% removed, respectively, at an electron beam absorbed dose of 20 kGy and an additive concentration of 0.02 M (mol/L). In most cases, NO_x was removed better with lower initial NOx concentrations and higher electron beam absorbed doses. As the irradiation strength (mA) of the electron beam increases, the probability of electron impact on the material accordingly rises, which may lead to increase removal efficiency. The results of the present study show that the continuous electron beam process using additives achieved more effective removal efficiency than either individual process (wet-scrubbing or EB irradiation only).