• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.443-446
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• 2002

In this paper, a phase difference of liveline insulator was measured and analyzed to estimate the contamination degree. The probability of accident rises according to the increase of the contamination. So the estimation of contamination degree is very important in design and maintenance of outdoor insulator. There are many methods to measure the contamination degree, but those methods use the spacial sense to measure the contamination degree. So, we have no information about the contamination from the liveline insulator, but there is a measurement of phase difference to estimate the contamination degree. The phase difference is varied with the increase of ESDD, so the contamination degree could be estimated by using those characteristics. The experiment is performed to analyze the interrelationship between contamination degree and phase difference. The variable condition is relative humidity that increases from 30 to 100 % in a chamber. We use the DAS program to measure and analyze the data. From the result, the variation of phase difference is different by the contamination degree, so we can confirm the possibility of estimating the contamination degree by the phase difference.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.153-156
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• 2000

To reduce the maintenance expense, and the possibility of electric outage and accident, we should optimize the outdoor insulation system. And for the optimization, accurate measurement for the degree of contamination with climatic conditions, such as wind, rain, and drought, should be carried. However the classical measuring method, brush wiping, has some problems in the aspect of man power, reliability, and expense. In this paper, we propose two type apparatus, which could detect the degree of contamination on insulators in outdoor insulation system, such as transmission and distribution line insulator and bushing. One use the leakage current, and the other use the oscillating frequency to check the degree of contamination. To avoid the oxidation of electrode AC source, and the low degree of contamination was applied. From the result of this investigation we could get the good relationship between the degree of contamination and the leakage current and oscillating frequency

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1472-1474
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• 2001

In this paper, a method was presented to estimate the contamination degree of outdoor insulator by the measurement of surface leakage current. Contamination is one of the most important factor to determine the performance of insulator. Thus, it is very important to exam the contamination degree on the outdoor insulator. There are many limits, such as reliability of data, interval of measurement and similarity of environmental conditions, in conventional method. So, the estimation technique for contamination has been needed to monitor the accurate pollution degree of insulator in situ. In this investigation, phase difference was measured to compare the variance of phase difference with the contamination degree and relative humidity. From the result, we could confirm the capability of the estimation method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1132-1141
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• 2004

The waveforms of the leakage currents for the surface discharge according to the degree of salt contamination and the variation of environmental condition on the EPDM polymer insulators, were shown in this paper. The variation phenomena of fundamental wave, 3rd and 5th harmonic waveforms were also shown from the beginning of the applied voltage and to the flashover voltage. To develop the technique of percentage contamination degree of EPDM polymer insulator according to the variation of environmental condition, the distortion degree of 3rd and 5th harmonic wave to the fundamental wave was utilized through the spectrum analysis for the waveforms of leakage current in the simulation of salt and fog test. The fact that distortion degree % of 3rd and 5th harmonics for fundamental wave is a necessary indicator for the assessment of contamination degree for the polymer insulators, was known.

• Journal of the Korean Society of Radiology
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• v.6 no.5
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• pp.335-342
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• 2012

This study aims to find a way to control infection of community radiology effectively by calculating the degree of contamination, culture and identifying the flora in radiology of five general hospitals in Gyeongsangbuk-do. Staphylococcus, Micrococcus, Pseudomonas stutzeri, Pseudomonas oryzihabitans were identified as surface flora. These are know to be pathogens of hospital acquired infection and there was no radiology-specific flora. Research subject hospitals were conducting similar infection control education but degree of contamination of each hospital showed significant difference. Difference in degree of contamination according to contact sources were analyzed by Contact sources were classified into technologist-using, patients-using and common-using materials. Analysis of each hospital's degree of contamination showed that patient-using materials were significantly more contaminated than technologist-using and common-using materials (p<0.001). Devices which are similar to each other in monthly average frequency of use showed no significant difference in degree of contamination, but general X-ray devices and chest boards which are used most frequently showed higher degree of contamination than others. In addition, hospital A, B and C which have heavier monthly average caseload showed relatively high degree of contamination on irradiation devices which are used by technologists only or by technologists and patients commonly, office desks and doorpulls. Hence it is considered that intensity of infection control education should be different according to the degree of monthly average caseload. This study provided an opportunity to aware that technologists' feeling of contamination is crucial for infection control of radiology, and the Accupoint ATP public hygiene monitoring system which was used in this study for measuring the degree of contamination was proved to be an effective measuring device for hospital acquired infection management.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.440-443
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• 2003

Recently, with the rapid growth of industry, environmental condition became worse. With the mix of the various contaminants, such as, salts, dust and industrial pollutants, synergy effect could be happened. So, many researches have been focused on the issue. The cause of natural accident could be classified as, lightning, rainstorm and contamination. However, the accident by contamination influences on the larger area than that by lightning, and, in the case of rapid contamination, it takes a shorter time than rainstorm. The salt contaminant is one of the most representative pollutants, and known as the main source of the accident by contamination. So, in this investigation we make a research on the prediction of contamination degree through the relationship analysis between the climatic factor and ESDD.

• 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.

• Journal of Pharmaceutical Investigation
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• v.3 no.4
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• pp.5-15
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• 1973

An investigation was carried out on a basis of the bacteriological examination with a view to detecting the degree of bacterial contamination for the 77 samples collected from the locally-sold liquid specialties. It's test period was 50 days from July 10 to August 30, 1971. Specially, the survey has put emphasis on the population of general bacteria and the identification of coli-form group, staphylococcus species, streptococcus species, bacillus species, fungi, and yeast species from liquid samples. The results obtained are summarized as follows; (1) For the 77 samples tested, the contamination of general bacteria was found out as minimun 0, i,e., maximum, $12{\times}10^4$ and the total average $45{\times}10^2$ per milliliter. (2) Although streptococcus species could not be detected with the samples, the contamination of the coli-form and staphylococcus species means the strong suggestion of the possibility of pathogenic bacterial contamination. (3) Specially, the products which stay in the neutral pH range and use suspending agents need to care for the microbial contamination in the manufacturing crocess. (4) It is thought necessary to perform the microbiological quality control in the liquid preparations only at least. (5) As the microbial contamination degree in the liquid decreases according to the elapse of time, the microbiological quality control will have to be carried out immediately after the completion of the manufacturing process in order to know the accurate degree. (6) The author thinks that the main reason of the microbial contamination in the liquid is the contamination during the manufacturing process. (7) For the purpose of prevention of the microbial contamination in liquid, therefore, it is more important to make efforts for the rationalization of manufacturing process, the improvement of equipment and environment, the specific training of workers for hygienic knowledges, etc. rather than the use of preservatives for the preparations.

• Journal of Environmental Health Sciences
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• v.18 no.1
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• pp.47-57
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• 1992

This study was performed to evaluate contamination degree of heavy metals in sediments of Han River, compared with other nation's evaluation method. The results were as follows 1. The contamination Ratio calculation method by heavy metal concentration in differnt fraction size has a limitation to apply to all of the areas of Han river because of its characteristics of sediment. As a result, this method applied to only 4 areas of Pal Dang, Wang Sook Chon, Uk Chon, and Bul Kwang Chon, and Contmination Ratio of heavy metals in those areas were relatively low of below 3. So it's considered that those areas have less contaminated from anthropogenic contaminants. 2. The Contamination Ratio calculation method by heavy metal concentration in different areasthat of upper area to be background level-has a limitation also to apply to Han river. But it is considered that this method was relatively suitable to apply, so it should be prepared evaluation standand method for them. Contamination ratio from background level as Pal Dang area were most high in An Yang Chon. So it must be prepared purification and control measure at An Yang Chon.

• Journal of Soil and Groundwater Environment
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• v.26 no.4
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• pp.8-19
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• 2021

In this study, the evaluation standard for nitrate nitrogen contamination degree (WELCUP) was established using six factors that influence the groundwater quality in Jeju Island. To do this, weightings, ranges, and ratings were assigned for each factor and the relative possibility of nitrate nitrogen contamination degree was evaluated using WELCUP index for each well. As a result of calculating the WELCUP index using groundwater quality data of 5,112 wells in Jeju Island for 27 years (1993-2019), all 61 wells with the WELCUP index value higher than 100 are distributed in Daejung and Hangyung watershed with relatively large area of farmland in Jeju Island. In particular, as the ratio of private wells is more than 64%, it is necessary that systematic management is needed for private wells in terms of nitrate nitrogen contamination. Consequently, based on the results of applying the WELCUP evaluation standard, it is necessary to select the prioritization of nitrate nitrogen contamination pathways project for groundwater wells in Jeju Island.