• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.6
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• pp.87-94
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• 2019

This paper contains the process of investigating the cause of fuel filter contamination of P&WC's PT6A-67A engine. An outline of the fuel filter contamination and configuration of the fuel supply line are specified. The analytical methods were classified into fuel component analysis and solid sediment analysis(EDX, TGA, optical microscope). In summary, the sulfur was detected from fuel tank sealant as a major contamination component. As a follow-up, P&WC and the Agency for Defense Development will conduct engine fuel filter cycle checks and fuel tank cleaning for engine operation.

• Journal of Korean Biological Nursing Science
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• v.16 no.2
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• pp.90-97
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• 2014

Purpose: The purpose of this study was to compare the contamination level of uniforms with nasal colonization of Staphylococcus aureus before and after the clinical practice of nursing students. Methods: This study was a survey research, conducting microbial culture by smearing the front surface and the pockets of uniforms, and the nasal cavity both before and after clinical practice on 70 nursing students. For the analysis, descriptive statistics, chi-square test, paired t-test were used for statistical analysis using SPSS 19.0. Results: The contamination level of uniforms increased more significantly after clinical practice on the front surface (p=.008) and pockets (p=.031) than before clinical practice, and Staphylococcus aureus, and Enterobacter aerogenes were detected. Conclusion: Through the results above, it is believed that it is reasonable to do the laundering of clinical uniforms of nursing students once a week. Because it is possible to disseminate disease germs with the contamination of clinical practice uniforms in a hospital environment, it is necessary to offer education for the laundering of uniforms with appropriate management.

• Journal of Soil and Groundwater Environment
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• v.17 no.1
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• pp.22-32
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• 2012

This study suggests a method to grade groundwater quality quantitatively using statistical approaches for evaluating the quality of groundwater in wells included in the Groundwater Quality Monitoring Network (GQMN). The proposed analysis method is applied to GQMN data from 2001 to 2008 for nitrate nitrogen, chloride, trichloroethylene, potential of hydrogen (pH), and electrical conductivity. The analysis results are obtained as groundwater quality grades of the groundwater representing each of the monitoring stations. The degree of groundwater contamination is analysed for water quality parameters, district, and usage. The results show that the degree of groundwater contamination is relatively high by nitrate nitrogen, bacteria and electrical conductivity and at Seoul, Incheon, Gwangju, Gyeonggido and Jeollado. The degree of contamination by nitrate nitrogen and trichloroethylene is especially high when the groundwater is used for agricultural and industrial water, respectively. It is evaluated that potable groudnwater in GQMN is significantly vulnerable to nitrate nitrogen and bacteria contamination.

• Progress in Superconductivity and Cryogenics
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• v.25 no.1
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• pp.6-10
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• 2023

2 K superfluid helium cryogenic system is the crucial component of many large accelerators. When the cryogenic system is operating at 2K@3129Pa, many room-temperature parts are connected to superfluid helium via tubes. Air Leakage in these connections may lead to air contamination of the cryogenic system. Air contamination may cause equipment failure in cryogenic systems and, in extreme cases, render the entire accelerator system inoperable. Helium guard is a technique that guards against air contamination of these sub-atmospheric pressure connections in 2 K superfluid helium cryogenic system. This paper introduces a typical 2 K cryogenic distribution design for large accelerators, and make risk analysis of air contamination. Finally, the analysis of specific leakage points and detailed engineering design are presented, which may be used as a reference when designing of a 2 K superfluid helium cryogenic distribution system.

• Journal of Pharmaceutical Investigation
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• v.39 no.4
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• pp.263-267
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• 2009

The purpose of this study is to evaluate the efficacy of stipulated cleaning process, and the prohibition of cross-contamination and microbiological contamination, which inadequate cleaning in multi-production could occur, through cleaning validation of multi-purpose facility used to produce five biopharmaceutical products as sterile injection. After production of five biopharmaceutical products such as hGH, rhGCSF, rhEPO, rhFSH and rhIFN using vial filling machine, the cleaning validation such as residual analysis of active ingredients or human serum albumin, measurement of total organic carbon (TOC), residual analysis of detergent and microbiological contamination were carried out. In the case of rhGH and rhGCSF clean validations, drug residues were not detected. Furthermore, in the case of rhEPO, rhFSH and rhIFN clean validations, human serum albumin residues were not detected. At TOC (total organic carbon) analysis, all clean validations gave the TOC of about average 137.93%, not more than 150% of acceptance criteria. At sodium analysis for the checking of residues of cleaning agent, sodium residues were not detected. In sterility test, they showed no microbiological contamination of bacteria and fungi. Thus, this cleaning validation was determined as successful in protection of cross-contamination and induction of safety in multi-purpose facility.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.2 s.29
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• pp.17-28
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• 2004

This study has tried to develop the modified DRASTIC Model by supplying the parameters, such as structural lineament density and land-use, into conventional DRASTIC model, and to predict the potential of groundwater contamination using GIS in Hwanam 2 District, Gyeonggi Province, Korea. Since the aquifers in Korea is generally through the joints of rock-mass in hydrogeological environment, lineament density affects to the behavior of groundwater and contaminated plumes directly, and land-use reflect the effect of point or non-point source of contamination indirectly. For the statistical analysis, lattice-layers of each parameter were generated, and then level of confidence was assessed by analyzing each correlation coefficient. Groundwater contamination potential map was achieved as a final result by comparing modified DRASTIC potential and the amount of pollutant load logically. The result suggest the predictability of contamination potential in a specified area in the respects of hydrogeological aspect and water quality.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.758-760
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• 1998

This paper provides the results of performance investigation of gas insulated switches(G/S) for distribution power system. In order to investigate anti-contamination capability of G/S we carried out electrical tests and material analysis on the body of G/S and it's accessories. Through this experiment we found out the lead cable of G/S had not anti-contamination capability and G/S had insufficient interval between each phase. In order to improve the performance of G/S for heavy contamination area it is indispensable to replace the lead cable to the new cable which has anti-contamination ability.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.85-88
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• 2001

Since mountainous area has access restrictions for field work, assessors need to establish a conceptual model of the contamination prior to the field investigation. In this study we established a conceptual model of the contamination based on site inspection and geological survey, followed by the field investigation for the petroleum spill site. In the conceptual model, we estimated that tile contamination should have spread by groundwater and topographical characteristics within the top soil layer. The spread of contamination through rock was not considered in the conceptual model due to impermeable characteristics of metasyenite. The contaminated environmental media of the petroleum spill site include soil and groundwater. According to the analysis result of the contamination, the volume of contaminated soil is estimated approximately 4, 150 cubic meters (7, 055 ton) with most contaminants existing along the groundwater flow within top soil layer.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.501-504
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• 2003

Sulfur isotope composition was used to identify the sources of groundwater contamination near abandonded coal mines. From the analysis of mine adit drainages, tailing seepages, and spring waters near the abandonded Hambaek and Hanchang coal mines in Kangwon Province, it was inferred that it the highly possible source of the contamination of spring water is acid mine drainage(AMD). Sulfur isotope composition showed that seepage from tailings seemed to have more effect on the groundwater contamination than mine adit drainage, which suggests the remediation and anti-contamination methods of tailing seepages not only mine adit drainage are required.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.695-698
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• 2000

This paper present the result of the investigation, the distribution of salt contamination with the influence of geographical condition. To get the ESDD data, a conventional brush washing method was adapted, and IC(ion chromatography) was used to measure the quantity of anions, such as Cl$\^$-/ and SO$_4$$\^$2-/. And we make an analysis on the distribution of salt contamination with the increase of distance from shore. With 10 month ESDD data, we seek the 95% ESDD value with interpolation method. With these analyses, we had obtained the formulation concerned with the distance from sea. And could know the composition of contamination.