• Culinary science and hospitality research
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• v.23 no.2
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• pp.159-168
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• 2017

This study was conducted to compare the food quality of domesticated species. Consumers surveyed for safe food intake and proper culture of food distribution. The results of the comparison study are as follows. Muscle moisture content, protein content, and fat content. K, P, and C showed relatively high values in the muscle of the sea bream. Fe showed low contents. As a result of measuring heavy metal component, Cd was not detected in sea bream and mullet, but $0.01{\pm}0.00mg/kg$ was detected in red mine. Other heavy metals were below the reference value or were not detected. Electrophoresis results showed that the band appeared at in red minefish. In the case of sea bream and swordfish, no distinctive features of the band were shown. In the case of sea bream, there was little difference in food science between the similar fish species and the red sea bream fish, but price was different. An environment should be created for consumers to buy the right ingredients at the price they want. It is necessary to educate consumers about food ingredients immediately.

• Composites Research
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• v.29 no.3
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• pp.111-116
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• 2016

The tilting pad journal bearing for the turbo compressor application has a role to support high speed and heavy loading rotor. White metal has been widely used for the bearing material but the conventional bearing is immediately suspended and induces serious serious damage to the rotor under the unexpected oil cut situation or the insufficient oil film formation. The carbon fiber reinforced composite having high specific stiffness, specific strength and excellent tribological characteristics can solve these seizure problems. In this work, the study on the durability of high thermal resistance carbon fiber/epoxy composite tilting pad journal bearing under oil cut situation was conducted. The material properties of the composite materials including tensile, compressive and interlaminar properties were measured at room and high temperature of oil cut situation. To investigate the possibility of failure of composite tilting pad journal bearing under oil cut situation, the stress distribution of the composite bearing was analyzed via finite element analysis and the Tsai-Wu Failure index was calculated. To verify the failure analysis results, the oil cut tests for the composite tilting pad journal bearing were conducted using industrial test bench.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.1
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• pp.27-32
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• 2009

Human hair is an excretory system for trace metals and thus metal content in human hair can reflect the body status. The investigation of trace elements in human hair has been correlated with the diagnosis of various diseases as well as the monitoring of deficiency statues in nutrition. Many chronic diseases may be related to mineral status, some may be related to toxic mineral. Hair samples were collected from 120 inhabitants of the city of Seoul, Korea. In this study the concentrations of 10 elements (Hg, Pb, Cd, Al, As, U, Bi, Sb, Ba, Be) in hair were determined by inductively coupled plasma mass spectroscopy (ICP-MS). The conclusions showed that people in Seoul, Korea were affected by some kinds of toxic minerals. The Hg concentrations of male are higher than those of female and reference range. The mean concentration of Sb was higher in the female than male and reference range. In age distribution, the mean concentration of Hg was in 40's are higher than 20's and 30's and reference range. The concentrations of Al were the highest in the 20's. After analyzing, we concluded that a compounded treatment should be conducted, which considers the variety of factors related to detoxification.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.33-37
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• 2019

In this study, the graded thermal properties of composites are obtained by difference in specific gravity of fillers including Cu, h-BN and GO powders in epoxy. Relatively heavy powders such as Cu and h-BN compared to GO mostly at the bottom layer, while light GO powders were dispersed in the top layer in the composites. The thermal conductivity of composites was gradually increased from 0.55 (0.52) W/mK to 2.82 (1.37) W/mK for GO/h-BN (GO/Cu) epoxy composites from surface to bottom. On the contrary, the coefficient of thermal expansion was decreased from 51 ppm/℃ to 23 ppm/℃ and from 57 ppm/℃ to 32 ppm/℃ for GO/Cu and GO/h-BN, respectively. The variation of thermal properties in composites is attributed due to intrinsic material properties of filler including thermal conductivity, morphology and the distribution by the specific weight of fillers. This simple strategy for realizing graded thermal composites by introducing different filler materials would be effective heat transfer at interface of heterostructure with large thermal properties such as inorganic semiconductor/plastic, metal/plastic, and semiconductor/metal.

• Journal of agricultural medicine and community health
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• v.47 no.3
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• pp.181-188
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• 2022

Objectives: The prevalence of diabetes mellitus was approximately 16% in populations of over age 30 years, and deaths from diabetes mellitus became the sixth most prevalent cause of death by disease. To assess the relationship between HbA1c and heavy metal level in blood and urine, targeted residents were evaluated in a vast steel industrial complex. Methods: We selected 414 subjects for analysis after applying the following exclusion criterion: 18 persons with diabetes mellitus. They took part in a questionnaire survey and underwent blood and urinary assessments. HbA1c and lead (Pb) level were measured in blood and, cadmium (Cd), inorganic arsenic (iAs) and mercury (Hg) were evaluated in urine. Two subgroups were divided by HbA1c 6.5%. Each subgroup was divided by 10th, 20th, 30th, 40th, 50th, 60th, 70th, 80th and 90th percentile levels of biological exposure index of the heavy metals for logistic regression. Results: Odd ratios have a tendency to increase as they go from the 90th to the 10th percentile of cadmium. However, lead, arsenic and mercury did not have significant relationships with HbA1c. In correction of age, region, gender and smoking history, a higher distribution in the subgroup with cadmium above 0.8318 ㎍/g creatinine (30th percentile) was demonstrated in the subgroup with HbA1c levels above the 6.5%, with an odds ratio of 5.26 (95% C.I. ; 1.44~19.17). Conclusion: This study found a significant correlation between urinary levels of cadmium and HbA1c in correction of several factors. It is meaningful that this outcome may be used as a basis for a study to establish the acceptable limit of urinary cadmium in Korea.

• Journal of Environmental Health Sciences
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• v.41 no.6
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• pp.449-457
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• 2015

Objectives: In Korea, the system of management of medical waste largely relies on the incineration method. Our study aimed to identify any regional imbalances between the generation and treatment of medical waste, and provide reference data for future policy in Korea. Methods: We analyzed data on the amount of medical waste from 2,000 hospitals in 2012, 2013, and 2014 obtained from the Korea Environment Corporation. In the Arc GIS program (version 10.2.3), the addresses of hospitals and incinerators were transformed into map coordinates. The amount of waste generated by each hospital and the amount incinerated were represented by density and size of a triangle symbol, respectively. Results: As of 2014, the total amount of medical waste from the top 2,000 hospitals was 136,073 tons, out of which about half (49%) was generated in the capital area. Eleven incineration companies (three in the capital area, two in the Chungcheong Provinces area, one in the Jeolla Provinces area, and five in the Gyeongsang Provinces area) treated this waste. For the years 2012, 2013, and 2014, about 60% of the medical waste generated from the hospitals in the capital area was treated within the capital area and about 40% was transported to other areas, especially the Gyeongsang Provinces area, for treatment. On the other hand, about 90% of the medical waste incinerated in the capital area originated from the capital area. Conclusion: Our results suggest a spatial imbalance between the generation and treatment of medical waste in Korea and warrants multilateral policies, including the expansion of on-site treatment, strengthening regulation of the containment of medical wastes, promoting reductions in medical waste and more.

• Resources Recycling
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• v.9 no.1
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• pp.52-62
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• 2000

In order to maximize the recycling of converter slag to the more valuable fields, such as high quality aggregates for construction, cement industry and flux for ion making. It will be very important to control the compositions and properties of converter slag to suit the purpose of utilizastion. In this study, converter slag (STELCO, CANADA) was mixed with 5%~30% $SiO_2$and 7% carbon, and then reduced at $1650^{\circ}C$. After the reduction was completed, the reformed slags were cooled to room temperature in the furnace. All of the slags were then characterized using SEM-EDX, XRD and chemical analysis. Also the compressive strengths and densities of the reformed slags were measured to compare with natural aggregates. XRD analysis shows that th phases of reformed slags are changed from bredigite+merwinite mixed phases of 10% $SiO_2$added reduction to akermanite phases of 20% and 30% $SiO_2$ added reduction. But the SEM-EDX analysis revealed that the phase distribution of the reformed slags was changed very sensitively and complicately depends on the change of slag compositions. And also the properties of reformed slags are changed very much depend on the phase distribution. About one third of Cadmium and on fifth of Vanadium are remained in reduction reformed converter slag. Another heavy metal elements such as cobalt, zinc, lead are removed up to more than 90-95% of original slag. The compressive strength and density of 25% $SiO_2$ added and reformed slag is very near to natural granite. This is superior more than 10% to Thyssen's $SiO_2$ added and oxidized converter slag aggregates.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.77-84
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• 2006

This study was conducted to find a system for screening organic resources with 16 species, 62 samples which were selected to randomizing point from city, province and industrial areas in the whole country. Content of organic matters were $65.3%{\sim}98.0%$ in all samples so that they were largely over than 60%, raw material regulation of compost. Concentrations of total nitrogen and total phosphorus were $0.7{\sim}4.8%\;and\;0.8{\sim}5.0$, they could look for effect of the nitrogen and phosphorus supply as a raw material of compost. In case of 8 elements concentrations of heavy metal, they were too high to use as raw materials of compost which were over to regulation limit in Cu, Cr, Ni, and As from fiber industry, Ni from food company and leather industry, and the others are adapt to limit levels. HEM contents fro the highest to $113mg\;kg^{-1}$ from liber industry and PAHs content were the highest to $3,462ug\;kg^{-1}$ from paper-mill manufacture. Distribution of PAHs concentiations were naphthalene>phenanthrene>pyrene>fluoroanthene>acenaphthene. $Microtox{(R)}\;EC_{50}$ values for bioassay were pharmaceutical company>paper-mill manufacture>industrial area sewage sludge>fiber industry>urban sewage sludge>metropolitan sewage sludge. HEM between Zn, Cu, and Ni was significant at the 99% and between Cd was significant at the 95%, Microtox between Hg and BEM significant at the 95%.

• Economic and Environmental Geology
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• v.39 no.3 s.178
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• pp.213-227
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• 2006

The geochemical evolution of mine drainage and leachate from waste rock dumps and stream water in Pb-As-rich abandoned Sechang mine area was investigated to elucidate mechanisms of trace metals. Total and sequential extractions were applied to estimate the distribution of trace metals in constituent phases of the waste rocks and to assess the mobility of trace metals according to physicochemical conditions. These discharged waters varied largely in chemical composition both spatially and temporally, and included cases with significant]y low pH (in the range 2.1-3.3), and extremely sulphate (up to 661 mg/l and metal contents (e.g. up to 169 mg/l for Zn, 27 mg/l for As, 3.97 mg/l for Pb, 2.99 mg/l for Cu, and 1.88 mg/l for Cd). Arsenic and heavy metal concentrations at the down-stream of Sechang mine have been decreased nearly to the background level in downstream sites (sites 8 and 16) without any artificial treatments. The oxidation of Fe-sulfides and the subsequent hydrolysis, of Fe(II), with precipitation of poorly crystallized minerals, constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace metals (i.e. Fe and As) to rivers. The dilution of drainage by mixing with pristine waters provoked an additional decrease of trace metal concentrations and a progressive pH increase. On the other hand, the most soluble cations (i.e. Zn) remained significantly as dissolved solutes until the pH was raised to approximately neutral values. With respect to ecotoxicity, it is likely that the Zn pollution is of particular concern in Sechang mine area. This was confirmed by the sequential extraction experiment, where Zn in wet waste-rock samples occurred predominantly in the exchangeable fraction (65-89% of total), while Pb was the highest in the reducible and carbonate fractions, and Cd, Cu and As in the residual fraction. Pb concentration in the readily available exchangeable fraction (34-48% of total) was dominated for dried waste rock samples. Considering the proportion of metals bound to the exchangeable and carbonate fractions, the comparative mobility of metals probably decreased in the order of Zn>Pb>Cd>As=Cu.

• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.236-240
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• 2011

Mercury known as quicksilver, is the most common cause of heavy metal toxicity. Toxicity caused by excessive mercury exposure is now being recognized as a widespread environmental problem and is continuing to attract a great deal of public concerns. The mercury genotoxicity could be its effect on DNA repair mechanisms, which constitute the defense system designated to protect genome integrity. The objective of this study is to confirm that mercuric chloride inhibits the repair of gamma ray-induced DNA damage. The earthworm of Eisenia fetida was chosen for this study because it is an internationally accepted model species for toxicity testing with a cosmopolitan distribution. Experiments were done to identify the levels of DNA damage and the repair kinetics in the coelomocytes of E. fetida irradiated with 20 Gy gamma rays alone or with gamma rays after 40 mg $kg^{-1}$ $HgCl_2$ treatment by means of the single cell gel electrophoresis assay. The Olive tail moments were measured during 0~96 hours after irradiation. The repair time in the animals treated with the combination of $HgCl_2$ and ionizing radiation was nearly five times longer than that in the animals treated with ionizing radiation alone. Also, E. fetida exposed to mercury showed a statistically lower repair efficiency of gamma ray-induced DNA damage. The results suggest that the mercury could even have deleterious effects on the DNA repair system. Influence of mercury on the DNA repair mechanisms has been confirmed by this study.