• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.321-327
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• 1998

This paper presented a case study on the application of on-line wear monitoring technique to a high duty air-turbo-compressor system. Main objects monitored were a gear unit and metal bearings, both shown frequent troubles due to the severe operation conditions at heavy dynamic load. The air-turbo-compressor system needs secure condition monitoring because it is one of the main utilities in steel making industry. Temperature and vibration characteristics have been mainly on-line monitored in this system for a predictive maintenance; however, it has been shown that they are not fairly good enough to give an early warning prior to the machine failure. In this work, an on-line Opto Magnetic Detector(OMD) was implemented for an on-line wear monitoring, which quantitatively measured the contamination level of both ferrous and non-ferrous wear particles by detecting the change in optical density of used oil. Results showed that the application of on-line OMD system was satisfactory in diagnosis of the machine system.

• 한국어병학회지
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• 제24권2호
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• pp.141-152
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• 2011

Growth, oxidative stress and antioxidant capacity of Fucus serratus exposed to high doses of Cd were examined. Two sites in Southwest England (Restronguet Point and Bantham Quay) were selected since they had different histories of metal contamination. 1~10 mg Cd $L^{-1}$ were treated to Aquil medium for up to 14 days. Similar levels of lipid peroxidation but different values of relative growth rates, cupric ion reducing antioxidant capacity (CUPRAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging capacity indicated that F. serratus has population-dependent antioxidant strategies. F. serratus demonstrated cadmium resistance with no visual symptoms for 14 days and the population from the polluted area seemed to have more powerful antioxidant strategies. However Fucus from the conserved area also showed protective anti oxidative mechanism.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.491-498
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• 2005

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur minerals pyrite($FeS_2$). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this study the generation characteristics and the prediction of ARD of various road cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Sixteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.

• 한국세라믹학회지
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• 제41권2호
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• pp.176-181
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• 2004

지정폐기물인 전기로 제강 분진은 현재 대부분이 매립 등 부적절하게 처리되고 있어 지하수 오염 등의 환경파괴를 일으킬 위험이 있다. 전기로 제강 분진의 자원화를 위하여 전기로 제강 분진/점토의 조성으로 다공체를 제조하였으며, 다공체의 기공 특성 분석을 하였다. 다공체는 서로 다른 두 개의 미세구조로 형성되어있으며, 표면부위의 미세구조는 치밀하고 검은색이 아니고, 내부부위는 검은색이며 다공성의 미세구조(black coring)를 갖는다. 블랙코아 부위의 면적과 경량화정도를 정량화하기 위하여 Ic(core index)와 Is(shell index)를 정의하였으며, 인공경량골재로서의 최적 경량화 조건은 Ic가 0.5이상이고, Is는 0.4이상이다.

• 한국패류학회지
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• 제7권1호
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• pp.87-93
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• 1991

Heavy metals, Cd, Pb, Cu, Mn, Zn in water, sediments and molluscs along coast line of Hwang-hae(Yellow sea)were examined. The collection sited werer close to esturies of Kum-gang and Mankyeong-Gang, where industries have been rapidly developed along the rivers in recent in recent years. Cadmium and lead in water were 0.32ppb and 4.12 ppb respectively on Kun-san, but not on Jang hang. In general, Cd, Pb, Mn and Zn were detected in the regions of mouth paart of rivers, whereas none or far less amounts were detected from Puan, a control site: 20km apart from estury of Mangyeong Gang. Cd and Pb in sediments of Kunsan were 0.46ppm and 9.31ppm respectively and 0.36ppm and 0.41ppm in Shim-po, but far less amounts in Byeon san.Heavy metals in shellfish were: Cd 0.78ppm and Pb 0.42ppm in Kun san, 0.74ppm and 0.74ppm in Shim po, and showed higher values compare to other sites. In general, heavy metal contamination of sedimets and molluscs in each are were correlated with grade of the water pollution due to heavy metals.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3535-3541
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• 2014

Bisphenol A is considered as pollutant, because it is toxic and hazardous to living organisms even at very low concentrations. Biological oxidation used for removing this organic from waste water is not suitable and consequently application of catalytic wet oxidation has been considered as one of the best options for treating bisphenol A. We have developed Fe/SBA-15, Ni/SBA-15 and Fe-Ni/SBA-15 as heterogeneous catalysts using the advanced impregnation method for oxidation of bisphenol A in water. The catalysts were characterized with physico-chemical characterization methods such as, powder X-ray diffraction (PXRD), FT-IR measurements, N2 adsorption-desorption isotherm, thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. This work illustrates activity of the catalysts for heterogeneous catalytic degradation reaction revealed with excellent conversion and recyclability. The degradation products identified were not persistent pollutants. GC-MS analysis identified the products: 2,4-hexadienedioic acid, 2,4-pentadienic acid and isopropanol or acetic acid. The leachability study indicated that the catalysts release very little metals to water. Therefore, the possibility of water contamination through metal leaching was almost negligible.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.72-75
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• 2004

The potential of electrokinetic (EK) technology has been successfully demonstrated for the remediation of heavy metal contaminated fine-grained soils through laboratory scale and field application studies. Arsenic contamination in soil is a serious problem affecting both site use and groundwater quality. The EK technology was evaluated for the removal of arsenic from two soil samples: kaolinite clay artificially contaminated with arsenic and arsenic-bearing tailing soil taken from the Myungbong (MB) mining area. The effect of cathodic electrolyte on the process was investigated using three different types of electrolyte: deionized water (DIW), potassium phosphate (KH$_2$PO$_4$) and sodium hydroxide (NaOH). The result of experiments on the kaolinite clay shows that the potassium phosphate was most effective in extracting arsenic, probably resulting from anion exchange of arsenic species by phosphate. On the contrary, the sodium hydroxide seemed to be most efficient in removing arsenic from the tailing soil, and it is explained by the fact that sodium hydroxide increased the soil pH and accelerated ionic migration of arsenic species through increase in desorption and dissolution of arsenic species into pore water.

• 한국환경과학회지
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• 제25권1호
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• pp.1-10
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• 2016

Bottom sediment pollution with heavy metals of the Sventoji River in Ukmerge, Lithuania using X-ray fluorescence spectrometry is analyzed in this article. During the research, qualitative and quantitative parameters of heavy metal concentrations and their distribution were investigated. This article presents obtained results of study, where bottom sediment samples were examined from both shores of the river of Sventoji. During this research, received data was treated using GIS software, which helped to interpolate the data of concentrations into the research polygon of the river. GIS software also helped to evaluate the urban runoff influence to the bottom sediment quality and exclude sources of pollution. The runoff dischargers which transport surface wastewater to the river were registered before sampling. At the mouth of streams, flowing into the river of Sventoji, additional samples were taken. After comprehensive river bottom sediment research there is a possibility to assess the extent of anthropogenic activity and its impact on the river ecosystem and human health.

• 대한기계학회논문집B
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• 제24권6호
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• pp.753-759
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• 2000

Photoelectric charging is a very efficient way of charging small particles. This method can be applied to combustion measurement, electrostatic precipitator, metal separation and control of micro-contamination. To understand the photoelectric charging mechanism, particle charging of silver by exposure to ultraviolet is investigated in this study. Average charges and charge distributions are measured at various conditions, using two differential mobility analyzers, a condensation nucleus counter, and an aerosol electrometer. The silver particles are generated in a spark discharge aerosol generator. After that process, the generated particles are charged in the photoelectric charger using low-pressure mercury lamp that emits ultraviolet having wavelength 253.7 nm. The results show that ultra-fine particles are highly charged by the photoelectric charging. The average charges linearly increase with increasing particle size and the charge distribution change with particle size. These results are discussed by comparison with previous experiments and proposed equations. It is assumed that the coefficient of electron emission probability is affected by initial charge. The results also show that the charge distribution of a particle is dependent on initial charge. Single changed particle, uncharged particle and neutralized particle are compared. The differences of charge distribution in each case increase with increasing particle size.

• 한국생활과학회지
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• 제18권6호
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• pp.1323-1336
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• 2009

This study examined the attitude and education need for food safety of high school students. Data were collected from 297 high school students in Gyeongbuk province through a self-administered questionnaire on December, 2008. Frequency, t tests, one-way analysis of variance, Duncan's multiple range tests, and chi-square tests were conducted using SPSS V. 14.0. Many respondents answered that the foods produced and distributed in Korea were not safe enough. Over a third of the respondents replied that the produced and distributed foods were not safe because of unsanitary food processing. They pointed out food additives threatened food safety the most, which was followed by heavy metal contamination, and endocrine disruptors. Most respondents mentioned difficulties in acquiring information concerning food safety, and obtained information from the media, such as TV and radio. The respondents required a high level of education regarding food safety, and preferred movie clips and broadcasting media the most. Finally, they pointed out food-related government organizations to be the most efficient educational institution for food safety.