• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.180-186
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• 2005

This paper discusses the development of mixtures for silica fume as a stabilization/solidification agent and a binder for industrial wastewater residue containing organic and heavy metal contaminants. The UCS (unconfined compressive strength) gradually increased to 66.7% as the silica fume content increased to 15%. The leaching of TOC (total organic carbon) and chromium decreased as more OPC (Ordinary Portland Cement) was substituted with the silica fume. When a mixture had 5% silica fume, it retained about 85% TOC, and chromium leached out 0.76 mg-Cr/g-Cr in acidic solution. Also, microstructural studies of the solidified analysis showed that the silica fume caused an inhibition to the ettringite formation which did not contrilbute to setting but coated the cement particles and retarded the setting reactions. The results indicated that the incorporation of silica fume into the cement matrix minimized the detrimental effects of organic materials on the cement hydration reaction and the contaminant leachability.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2107-2111
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• 2023

The aim of the study is the activity concentration measurements of organic and inorganic ¹⁴C in the discharges of JSC "Institute of Nuclear Materials" (INM). In INM the research water-water reactor "IVV-2M" is operating. Collecting of ¹⁴C species was performed using a ¹⁴C sampler with a chromium oxide and platinum catalysts at different temperatures: 400, 550 and 700 ℃. The measurements of ¹⁴C activity were performed using a liquid scintillation counter. The share of organic ¹⁴C in emissions ranged from 0.30 to 0.84 and depends on the temperature of the catalyst, core structure and reactor operating mode.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.81-82
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• 2007

3가크롬 도금액은 크롬원 (황화물계 또는 염화물계), 착화제, 완충제, 전도보조제, 산화방지제, 유기첨가제등으로 구성되어 있으며, 특히 착화제와 유기첨가제가 용액의 안정성 및 균일전착성에 미치는 영향이 크다고 보고되고 있다. 본 연구에서는 카르복시기의 작용기를 갖는 유기산을 착화제로 사용하고, 다양한 유/무기 첨가제의 조합 및 첨가량을 조절하여 크롬의 전착특성을 고찰하였다.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.36-44
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• 1994

A study was carried out in order to investigate the removal efficiencies and removal characteristics of heaw metals such as Pb, Cd, Cr, Cu in raw water by one of conventional water treatment processes. The coagulants used in this study were Alum and PAC. Three kinds of water samples were provided: kaolin water, kaolin water mixed with humic acid and raw water from Han River mixed with suspended matter deposited on raw water inlet pipe. Heaw metals were added to the water samples with their respective turbidity, and jar tests were performed. In the results from heaw metal removal studies, lead might be adsorbed or exchanged on the particle surface (SS) rather than react with organic matter added. Cadmium was affected on the dissolved organic matter. Chromium was affected by the both dissolved organic matter and SS concentration, and the restabilization and the enmeshment appeared at moderate (50~80 NTU) and high (100 NTU) turbidity as defined in this experimenL The removal efficiency of copper was relatively little affected by the dissolved organic matter but by SS concentration in comparison with other heavy metals. In these studies as to the raw water turbidities and concentration of heaw metals, it is proved out that the removal efficiency on heaw metals in both cases of PAC and Alum as coagulants was not significantly different.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1374-1377
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• 2005

Top-emitting organic light-emitting diode (TEOLED) was fabricated on flexible substrate of PES film. Aluminum and Chromium multilayer was used as an anode of TEOLED and the TEOLEDs of Cr(20nm)/Al(100nm)/Cr(20nm)/NPB(60nm)/Alq(60nm)/LiF(1nm)/Al(2nm)/Ag(20nm)/NPB(200nm) has been fabricated on PES film and Si wafer for control device. The TEOLED on PES film which had good anode surface morphology, showed very similar device characteristics to that on Si wafer.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.657-662
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• 2005

Extractions fro fertilizer and soil samples were performed to yield the operationally defined fractions 'soluble' chromate (extractable with $NH_4NO_3$), 'exchangeable' chromate (extractable with phosphate buffer pH 7.2), and these results were compared with the data obtained by extractions with ammonium sulfate, borate buffer pH 7.2, saturated borax pH 9.6, and polyphosphate (Graham's salt). In order to maintain the pH of extractant solution about constant, the concentration of extractant buffer had to be raised to at least 0.5 M. The results strongly depended on the kind of extractant, and the solid: liquid ratio. For most of the samples investigated, the extraction efficiency increased in the order borate-sulfate-nitrate-phosphate. Whereas the recovery of $K_2CrO_4\;and\;CaCrO_4$ added to the samples of basic slags prior to the extraction was about complete, the recovery of added $PbCrO_4$ was highly variable. In soil extracts, the color reaction was interfered from co-extracted humics, which react with the chromate in weak acid solution during the time period necessary for color reaction (1 hour). However, this problem can be overcome by standard addition and subtraction of the color of the extractant solution. In soil extract of about pH < 7, organic material reduced chromate during the extraction period also, and standard addition of soluble chromate is recommended to prove recovery and the stability of chromate in the samples. In admixtures of soils and basic slags, results for hexavalent chromium were lower than from the mere basic slags. This effect was more pronounced in phosphate than in nitrate extracts. As a proficiency test, samples low in organic carbon from contaminated sites in Hungary were tested. The results from $NH_4NO_3$ extracts satisfactorily matched the results of the Hungarian labs obtained from $CalCl_2$ extractants.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.67-74
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• 2010

Chromate conversion coating is a coating technique used to passivate aluminum, zinc, cadmium, copper, silver, magnesium, tin, and their alloys to slow corrosion. The process uses various toxic chromium compounds, which may include hexavalent chromium. The industry is developing less toxic alternatives in order to comply with substance restriction legislation, such as RoHS. One alternative is to develop a Cr-free coating solution. In this study, eco-friendly, Cr-free solutions (urethane solution S-700, organic/inorganic solution with Si LRO-317) were used. Test specimens were dried in a drying oven at $190^{\circ}C$ for 3, 5, 7, and 9 minutes. Corrosion resistance was evaluated using a salt spray test for 72 hours. The results show that the optimum corrosion resistance was achieved at $190^{\circ}C$ for five minutes for EGI and three or five minutes for HDGI, respectively. The adhesive properties of the two types of coating solutions were superior regardless of drying time.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.673-682
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• 2016

In this study, we investigated influent and effluent water pollutants in 53 Public Sewage Treatment Works (PSTWs) where industrial wastewater or landfill leachate is combined four times for two years from 2014 to 2015. Also, we analyzed the characteristics of heavy metals and volatile organic carbons at influent and effluent of these PSTWs caused by sewage treatment combined with industrial wastewater or landfill leachate. As a result, six heavy metals such as barium, copper, iron, manganese, nickel and zinc, and four volatile organic carbons (VOCs) including phenols, di(2-)ethylhexyl phthalate (DEHP), formaldehyde and toluene were observed above detection limits in most of PSTWs. Also, it was revealed that six heavy metals such as hexavalent chromium, mercury, cadmium, chromium, nickel and selenium, and four VOCs including 1,1-dichloroethylene, vinyl chloride, naphthalene, and epichlorohydrin were observed more frequently according to precipitation. As a result of reviewing the monitoring data on "Water Quality Monitoring Networks" in lower watersheds of PSTWs, both heavy metals and VOCs were below detection limits, indicating that the effluent water had little influence on the watershed. Nevertheless for the better management of influent and effluent pollutants in PSTWs, it is necessary to establish the advanced management plans for water pollutants in PSTWs, which include a list of priority substances management, monitoring plans, and guidelines for industrial wastewater and landfill leachate combined in PSTWs.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.759-768
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• 2005

The study was designed to estimate the in vitro rumen by-pass rate of both chromium methionine chelate as an organic supplement and $ClCl_3$ as an inorganic supplement. Rumen by-pass rates of the supplements were evaluted by comparing ruminal metabolites in rumen fluid and Cr and methionine contents in the body of ruminal microorganism. For in vitro digestion examination, basic nutrients for ruminal microbes were supplied with 7g(DM) of feed, 2g of rice straw, and 2g of corn silage per each incubation jar. Three treatments including Control(no supplementation of Cr), T1(1000ppb supplementation of $ClCl_3$) and T2(chromium methionine chelate supplementation equivalent to 1000ppb of Cr content) were prepared with five replications per each treatment. pH of T2 was lower than that of Control and T1 regardless of incubation time. Ammonia content was higher in T2 than in Control and T1 during first 6 hours of incubation. However, the ammonia content in Control was remained low after 6 hours. Total volatile fatty acids(VFA) content in control was increased constantly as incubation time was extended. Therefore, VFA content in T1 and T2 were significantly lower (P<0.05) than those of Control. Dry matter recovery rate by ruminal microorganism was the lowest in T1, however ruminal microbial population was increased most efficiently in T2 during 12 hours of in vitro incubation. Cr concentrations in the body of ruminal microbes were not different(P>0.05) between Control and T2, but it was significantly high in T1(P<0.05). Contents of methionine and cystine in ruminal microbes also were not different between Control and T2(P>0.05), but it was relatively low in T1. Based on the above results, the chromium methionine chelate was believed to by-pass rumen and could remain intact until it reaches small intestine compared to inorganic chromium. This results implies that chromium methionine chelate could be more effective to function in the small intestine of ruminant animals.

• Journal of Power System Engineering
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• v.19 no.6
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• pp.12-18
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• 2015

Austenitic stainless steels generally experience the occurrence of chromium-depleted zones at the boundaries, known as sensitization, caused by the carbide precipitation that takes place due to a welding process or heat treatment. Normally, the depleted zones become the focus of the intense corrosion. In this study, the Cr-free organic/inorganic hybrid solution was developed, and the artificially degraded STS316S and STS347H with the solution-coating investigated the corrosion resistance by salt spray test. Both the OIBD-1 and OIBD-2 solutions improved the corrosion resistance of STS310S and STS347H. The corrosion resistance with the OIBD-1 solution was better than that of OIBD-2 solution. Additionally, Both solutions have been proven excellence in adhesion ability, boiling water resistance and flexibility. However, a problem of rubbing after the boiling was found out to be overcome.