• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.469-478
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• 2022

Tritium was extracted from tritium-contaminated aluminum samples by heating it in a high-temperature furnace at 200, 300, or 400 ℃ for 15 h. The extracted tritium was analyzed by using a liquid scintillation counter (LSC); the sample thicknesses were 0.4 and 2 mm. The differences in tritium extraction over time were also investigated by cutting aluminum stick samples into several pieces (1, 5, 10, and 15) with the same thickness, and subsequently heating them. The results revealed that there are most of the hydrated material based on tritium on the surface of aluminum. When the temperature was increased from 200 or 300 ℃-400 ℃, there are no large differences in the heating duration required for the radioactivity concentration to be lower than the MDA value. Additionally, at the same thickness, because the surface of aluminum is only contaminated to tritiated water, cutting the aluminum samples into several pieces (5, 10, and 15) did not have a substantial effect on the tritium extraction fraction at any of the applied heating temperatures (200, 300, or 400 ℃). The proportion of each tritium-release materials (aluminum hydrate based on tritium) were investigated via diverse analyses (LSC, XRD, and SEM-EDS).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.73-74
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• 2022

The corrosion inhibitive effect of a new hydrazone-based heterocyclic compound for steel in simulated concrete pore solution with 3.5 wt.% sodium chloride was investigated by experimental and computational techniques. Electrochemical studies, up to 30 days of immersion, and surface analysis (X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscope (SEM)) were performed to assess the corrosion protection abilities of investigated compound for steel rebar. Results showed that adding the organic compound to the chloride contaminated concrete pore solution decreased the corrosion rate of the steel rebar thanks to the effective adsorption of inhibitor molecules. After 30 days of immersion of steel rebar in inhibited chloride contaminated synthetic concrete pore solution, the inhibition efficiency exceeded 80% at low concentration of 1 mmol/L. Computational studies by Density Functional based Tight Binding (DFTB) method revealed the formation of covalent bonds between the hydrazone molecule and the iron surface.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.59-60
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• 2023

The corrosion of steel rebar embedded in the coastal areas is corroding once the chloride ions ingress through the pores of the concrete. Therefore, in the present study, a 100 ㎛ thick Al and Zn coating was deposited by an arc thermal spray process onto the steel. The corrosion studies of these deposited coatings were assessed in 3.5 wt.% NaCl contaminated concrete pore (CP) solution with immersion periods. The results show that the Al coating is more corrosion resistance compared to the Zn coating attributed to the formation of gibbsite (γ-Al(OH)₃) whereas Zn coating exhibits Zn(OH)₂ onto the coating surface as passive layer. The Zn(OH)₂ is readily soluble in an alkaline solution. Alternatively, γ-Al(OH)₃ on the Al coating surface is less solubility in the alkaline pH, which further provides barrier protection against corrosion.

• Journal of Surface Science and Engineering
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• v.42 no.6
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• pp.301-310
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• 2009

Recently, it has been increasing for the eco-environment plating and surface treatment of eco-environment to decrease hazardous materials. Particular eco-environment can be applied to electronics or automotive parts of industry. In the case of mobile phone, if there were fired, the products bearing dye may be contaminated with the hazardous and wasted. we can obtain the original metal color by electro coloring by metal salt, get rid of hazardous gas, decrease the wasted sludges. Now, the industrial patent number is increasing in Korea, we can accomplish the development of green industry by supporting technical trend of the plating and surface treatment in eco-environment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.9
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• pp.1013-1021
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• 2004

This paper presents the results of spectrum analysis of leakage current waveforms on contaminated polymer insulators under fog conditions. This is a basic study on development of a monitoring for aging degree and surface pollution state using distortion rate(%) of 3rd and 5th harmonics according fundamental frequency[60Hz] under environment conditions. Arcing on the surface was always associated with distortion in the leakage current ; hence the low frequency components of the leakage current can be used as a means to evaluate the surface degradation. The results indicate that the distortion rate by spectrum analysis is available for the monitoring of contamination condition of EPDM Polymer insulators.

• Journal of the Korean Society of Safety
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• v.12 no.2
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• pp.65-69
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• 1997

Especially, Fiber glass Reinforced Plastics(FRP) is the best composite insulating material which has been so far. Therefore, it's worthy of notice to investigate on the corona electrified composite insulating material by surface condition. And then some other materials will be focussed on. In this study, charge decay were measured with charging-time and grid voltage on FRP composite material surface in order to analyze the mechanism. As a result we have studied that the way of the composite glass fiber(GF) and Polymer and the condition of the contaminated surface was different. In case of the GF is mixed with vertical, charge decay speed is fast because the charge is easily leaked. On the other hand, the surface charge decay speed is depend on conductive or insulated of the contaminant.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.779-787
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• 2010

In this paper, We introduce electrical tracking generated from surface activity associated with flow of leakage current on insulator under wet and contaminated conditions and design electrical tracking pattern recognition system by using LabVIEW. We measure the leaking current of contaminated wire by using LabVIEW software and the NI-c-DAQ 9172 and NI-9239 hardware. As pattern recognition algorithm and optimization algorithm for electrical tracking system, neural networks, Radial Basis Function Neural Networks(RBFNNs) and particle swarm optimization are exploited. The designed electrical tracking recognition system consists of two parts such as the hardware part of electrical tracking generator, the NI-c-DAQ 9172 and NI-9239 hardware and the software part of LabVIEW block diagram, LabVIEW front panel and pattern recognition-related application software. The electrical tracking system decides whether electrical tracking generate or not on electrical wire.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.783-789
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• 2003

This study was conducted to reuse the rice straw ash as washing agent for oil contaminated soils. The results are summarized as follows. The physical characteristics of rice straw before and after burning were as follows ; In case of burning rice straw 1g, the rice straw ash was generated 0.14g and pH was changed neutrality into alkali(pH 10.9) and specific surface area was increased to five times and particle distribution was corresponded to fine silt.(under 0.05mm) The physical characteristics of rice straw ash were Carbon 10.9%, Hydrogen 1.5%, Oxygen 23.4%, Nitrogen 5.2%, Sulfate 1.2% and chemical characteristics were Si 189.2ppm, Ca 10.2ppm, Mg 4.7ppm. Oil cleanup ratio by pH variation were about 40∼50% of initial concentration of oil by pH 10∼11. As the result of cleanup comparative experiment, the rice straw ash was about 20∼30%, the tritonX-100 about 40∼50% of washing efficiency, and then in the future it will be possibility of substitute washing agent.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.371-376
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• 2002

A biosurfactant-producing bacterial strain was selected from diesel-contaminated soil by measuring the oil-film collapsing activity and identified as Pseudomonas aeruginosa D2D2. When glucose and olive oil were used as carbon sources, 11.46 g/1 of biosurfactant was obtained. Based on TLC analysis, the biosurfactant produced from P. aeruginosa D2D2 was identified as a glycolipid, consisting of two types of biosurfactants (Type I and Type II). The purified glycolipid reduced the surface tension of the culture from 72 dyne/cm to 27 dyne/cm. The hydrophilic and hydrophobic moiety of the biosurfactant were rhamnose and ${\beta}$-hydroxydecanoic acid, as determined by FAB-MS and NMR analyses, respectively.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.21-22
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• 2005

A study on the wear characteristics of the white metal(Sn-base alloy) bearing as a function of particle contamination level was conducted in order to establish control criteria of the lubricant in the 2-stroke marine diesel engine. Particle contamination level of the lubricants ranged from NAS 10 to 12 for the experiments. Bar-on-plate type wear test was performed using reciprocating wear tester. Based on this study it was found that there was no noticeable difference in weight loss of the white metal for NAS10 and NAS11(particle contamination level). Surface roughness of the white metal bearing after the wear test of 8hrs for the highly contaminated lubricant(NAS12 level) was up to $6{\mu}m$ in Rmax whilst that of the less contaminated lubricants(NAS10 & 11) was less than $1.5{\mu}m$ in Rmax.