• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.2
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• pp.185-194
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• 2018

The objective of this study was to compare the shear bonding strength of zirconia after cleaning the crown contaminated by saliva or blood and determine the effect of thermocycling. 180 specimens were embedded in acrylic resin. 20 Specimens in the positive control group were bonded with resin cement without contamination. 20 Specimens in the negative control group were washed with water for 20 seconds and then dried for 10 seconds. 120 Specimens contaminated by saliva or blood were cleaned by using three cleaning methods: 37% phosphoric acid gel, commercial cleanse, and 2.5% NaOCl. All samples were bonded with resin cement and divided into two subgroups: One was not aged, and the other was tested with 30,000 thermocycling. In both groups contamination by saliva and blood, no statistically significant difference was not found in control, groups cleansed by commercial cleanser and 2.5% NaOCl. When the groups cleansed with water and 37% phosphate gel were compared with the control, significantly low shear bond strength was shown. Thermocycling group showed statistically significantly low shear bond stress compared to the groups without thermocycling. When zirconia was contaminated by saliva or blood, its original shear bond strength could be obtained if it was cleaned with commercial cleanser or 2.5% NaOCl.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1886-1891
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• 2013

To inactivate the microorganisms on the surface of blueberries after harvest and to secure microbial safety, a bubble-aqueous chlorine dioxide washing system was developed. After treating the freshly prepared blueberries with the bubble-aqueous chlorine dioxide washing system, the changes in the microbial populations and quality of the blueberries were determined during storage $4{\pm}1^{\circ}C$. Microbiological data indicated that the populations of total aerobic bacteria, yeast and mold decreased by 1.4 and 1.3 log CFU/g at the treatment of 20 ppm aqueous chlorine dioxide with the system, respectively. There was no significant difference in color change and weight loss during storage among treatments. In addition, this washing system could handle approximately 60 kg of blueberry per hour, resulting in labor-saving. Therefore, these results clearly suggest that the bubble-aqueous chlorine dioxide washing system could be useful in improving the microbiological safety of fresh blueberries after harvest.

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.51-57
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• 2011

Generally, ready-mixed concrete(RMC) gets hardened by time, so the remaining concrete in the drum should be cleaned. But if the RMC waste water generated from this is discharged to soil without any treatment, the strong alkaline elements and heavy metals affect water and ecosystem pollution. Although about 10 to 15% of water used for cleaning in the RMC factory is discharged to soil or river, the concrete report of this affecting soil pollution has not been sufficient. Hence, in this study it was analyzed the extraction of cleaning water from RMC factories all over the country and heavy metal and pH components remaining in soil when this is penetrated to various soils having water permeability. The specimens used for the experiment are weathering soil and soils having different particle size, and it is made to be penetrated to those for 24 hours while fixed thickness of the layer is maintained. Cleaning water is divided into that before deposition treatment(sludge water) and that after deposition treatment(upper water) to be penetrated into soil, and according to the result of penetrating sludge water to soil, Cu and Mn, Fe, and Zn were found to be remained over 23 to 90%. However, it is analyzed that in upper water having deposition treatment, Cu and Mn remain as 60% or more only in weathering soil.

• Resources Recycling
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• v.30 no.1
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• pp.60-65
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• 2021

The recycling of titanium turning scraps requires the removal of cutting oil and other contaminants remaining on the surface. In this study, an experiment was conducted in which titanium scraps were cleaned by a combination of ultrasonic immersion-steam cleaning and subsequent drying at high temperature. To determine the removal mechanism of cutting oil, the contact angle between titanium surface and cutting oil was measured. The result confirmed the optimum condition of the immersion solution of the titanium turning scraps. In the case of immersion cleaning of Na4P2O7 aqueous solution, the degree of carbon removed in the cutting oil was the highest at 50℃, and it was confirmed that the carbon content obtained from the combination of steam cleaning and ultrasonic immersion-steam cleaning was lower than that from steam cleaning after ultrasonic immersion. The oxidation and decomposition behaviors of cutting oil were investigated using Thermogravimetric analysis (TGA) and the result was applied in the high temperature drying process. From the results of the high temperature drying tests, it was concluded that 200℃ is the optimal drying temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.10
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• pp.1265-1269
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• 2017

This study was performed to evaluate the effects of combined treatment of clove bud essential oil (CBEO) and mild heat (MH) on inactivation of Escherichia coli O157:H7 inoculated onto red oak leaves. Combined treatment of 0.2% CBEO with MH at $50^{\circ}C$ exhibited the highest inhibitory effect against E. coli O157:H7 among treatments, resulting in 1.45 log reduction compared with water washing treatment. In addition, inhibitory effect of the combined treatment was maintained during storage of red oak leaves at $4^{\circ}C$ for 9 days, showing 1.67~2.25 log reductions compared with non-treated samples. Thus, these results indicate that combined treatment with CBEO/MH can be used to ensure the microbiological safety of fresh leaf vegetables such as red oak leaves during storage.

• Journal of Korea Foundry Society
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• v.41 no.2
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• pp.139-143
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• 2021

A type of titanium alloy, ferro-titanium, is the main material used to manufacture steel and stainless steel. Considering economic aspects, ferro-titanium ingots are intended to be manufactured using low-cost titanium scrap, and the best pretreatment process for removing impurities from recycled titanium scrap surfaces was studied here. Instead of ordinary acid or organic solvents, ecofriendly methods were researched and applied, and chip scrap materials were used. A high-quality ferro-titanium ingot was manufactured from titanium scrap after a pretreatment process was applied, and the impurities and properties were analyzed and compared with commercial material standards through a component analysis.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.73-76
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• 1999

인화성 액체는 소방법상의 4류 위험물로 분류되며 공업용 연료, 세척, 용제 등의 원료로서 그 사용빈도, 취급, 저장되는 양이 타 위험물에 비하여 매우 많을 뿐 아니라 그 종류도 다양하며 화학공업 분야에서 광범위한 사용이 이루어지고 있다. 이러한 대부분의 인화성 액체는 낮은 B.P. 빠른 증발속도, 저인화점의 물리적 특성으로 가연성 증기의 형성이 용이하고 화재 및 폭발의 위험성과 다량의 유독성 증기의 발생 위험이 존재하고 있다. (중략)

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.27-34
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• 2006

We investigated the question whether the efficacy of cleaning tear components on RGP lens and preserving the superior wettability of RGP lens depended on the different type of contact lens care system - RGP lens care solution, SCL care solution, combined solution both for SCL and RGP lens or saline solution. The removal efficacy of the deposited protein was examined by Lowry protein assay and Scanning Electro Microscope(SEM) and residual lipid concentration on RGP lens was determined by High Pressure Liquid Chromatology(HPLC). Wettability was assessed with an equilibrium water-in-air contact angle method. When cared by RGP lens solution, it was demonstrated that 62 percent out of the adhered protein on RGP lens were removed and the removal efficacy of RGP lens solution was not only 4 times than saline solution and the alternative but also higher twice than SCL solution. Contrarily, the SCL solution had the most excellent removal efficacy of the adhered protein on SCL. These results suggest that the cleaning efficacy is thought to be affected by the other factors like the viscosity of care solutions, which mutual contact between RGP lens and care solutions is on the increase due to the viscosity enhancer in RGP lens care solution. RGP lens solution had the greatest removing efficacy to cholesterol and the residual cholesterol concentration was decreased to 50%. It is significant for RGP lens to preserve the superior wettability which means the predictive value for comfortable wearing and it showed that the RGP lens solution offered the most excellent efficacy to maintain the surface wettability. Combined solution both for SCL and RGP lens had weak efficacy of cleaning and maintaining wettability for RGP lens compared to RGP lens care solution.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.238-242
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• 1998

Chicken carcass microflora were evaluated for aerobic microorganisms after defeathering, evisceration, washing, chilling, and sanitizing during a commercial chicken processing and storage at wholesale and retailsale levels. Sampling was at between December 1997, and March, 1998. Tap water washing and sanitizing with 25 ppm chlorine for 10 sec significantly (P<0.05) reduced aerobic plate counts (APC) and gram-negative bacterial counts (GNC) on chicken carcasses from a commercial chicken-processing plant. After 4 days at $2{\pm}2^{\circ}C$, APC and GNC on chicken carcasses in retailsale store rapidly increased compared to those in wholesale store (P<0.05). Chicken wings from retailsale store significantly (P<0.05) decreased generation time (GT) compared to other chicken carcasses.

• 월간 기계설비
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• no.12 s.209
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• pp.34-43
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• 2007

환경부는 산하 수처리선진화사업단에서 수돗물 수질개선대책의 일환으로 연구개발한 옥내급수관 진단, 세척 및 갱생기술을 적용, 서울시와 공동으로 시범사업을 실시한다고 밝혔다. 이 사업은 서울 둔촌동 주공아파트 2개동 80세대를 대상으로 약 1억2000만원의 예산을 들여 지난 8월 말부터 시행, 수돗물 녹물발생 방지를 위한 갱생기술의 완성도를 검증·확인한다는 것. 기존 옥내급수관 갱생기술은 평균 관직경 15mm인 소형관에 대한 정밀시공이 어려워 녹이 재발하는 경우가 많았다. 하지만 이번에 개발된 기술은 수도관 내부의 녹 제거 및 관 내부 표면이 균일토록 코팅할 뿐 아니라 시공 후 마이크로 로봇을 이용, 관 내부 촬영 및 절연도 체크를 통해 코팅 완성도를 확인, 녹 재발 가능성을 미연에 방지한다. 이번 기술이 검증되면 환경부는 선박배관, 빌딩, 냉각수배관, 소화용배관, 산업용배관 등에도 확대 적용하고 해외진출을 통해 물산업 육성 아이템으로 발전시킬 계획이다. 한편 환경부는 지난 2005년 수도법을 개정, 건축연면적 6만$m^2$이상 다중이용건축물과 연면적5,000$m^2$이상 국.공립 공공시설은 준공 5년 후부터 매년 수질검사를 실시, 결과에 따라 수도관을 세척·갱생 또는 교체토록 올해 1월부터 의무화 하고 있다.