• Title, Summary, Keyword: Contamination

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Contamination Control of Optical Observation Satellite

  • Lee, Chang-Ho;Lee, Choon-Woo;Cho, Young-Jun;Whang, Do-Soon
    • Bulletin of the Korean Space Science Society
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    • pp.28.3-28.3
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    • 2008
  • Contamination has the potential for degrading the performance of the optical payload beyond the limits defined by mission requirements, therefore it must be considered a risk to system performance and must be mitigated. To mitigate contamination problem, contamination budget is allocated according to the contamination requirements which is derived from contamination effect analysis. Once the contamination budget is allocated, prediction for on-ground and in-orbit contaminants amounts and cleanliness control is performed. In this article, typical contamination control for observation satellite is described.

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A Estimation of Contamination Degree by the Measurement of Phase Difference on the Outdoor Insulator (옥외절연물의 오손도 파악을 위한 위상차 측정)

  • 심규일;이원영;한상옥;박강식
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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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.

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Investigation of Microbial Contamination and Working Environment in University Foodservices (대학급식소 작업시설과 환경의 미생물 오염도 분석 및 작업환경 실태조사)

  • Park, Soon-Hee;Moon, Hye-Kyung
    • Journal of the Korean Dietetic Association
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    • v.23 no.2
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    • pp.180-191
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    • 2017
  • The purpose of this study was to identity the probability of cross-contamination from the environment. For this, we examined foodservices at 20 universities/colleges for microbiological analysis of their working facilities and environment as well as their preventive equipment against cross-contamination. Seventy percent of the 20 foodservices were found to maintain one unified working area, which suggests high probability of contamination of food/utensils/equipment in the cooking area by pre-preparation or dish washing. According to the microbiological analysis, the hygiene acceptance ratio of working facilities in the clean zone was 70%, which was higher than the average 45% hygiene acceptance ratio of working facilities in the contamination operating zone. There was a significant difference in the total plate count (P<0.001) and coliform count (P<0.01), which demonstrates that work tables in the clean zone were in a good state compared to those in the contamination operating zone. In the contamination operating zone, refrigerator shelves had a high probability of cross-contamination. Regarding the floor surface and airborne microbes, cooking areas which should be maintained as clean zones had higher cross-contamination probability than those in the contamination operating zone. So corrective actions such as cleaning and sanitizing, keeping dry floors, lowered temperature and humidity, shoe disinfecting facilities, and checking concentrations, are necessary to manage floor surfaces and airborne microbes in the cooking area.

토양측정망과 특정토양오염관리대상시설 부지 등에서 토양오염조사의 효율성 제고를 위한 환경정책의 고찰

  • Park Yong-Ha;Park Sang-Yeol;Yang Jae-Eui
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • pp.11-15
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    • 2006
  • Attempts were made to increase an efficiency of soil contamination investigation systems (SCISs) including Soil Network and Special Soil Contamination Management Facility Sites in Korea. In order to increase low efficiencies resulting from inappropriate SCISs, possible policy suggestions are driven based on the results from problem findings of Korean policy and comparisons of policies on industrialized countries including United States, United Kingdom, Germany, the Netherlands and Japan. First, functions of Soil Environment Conservation Act (SECA) on liability should be updated and reinforced to initiate a soil contamination investigation process for stakeholders including an owner(s) or a responsible party(ies) of the potentially soil contamination sites positively. Second, appropriate SCISs should be emerged for implementing the Soil Network and Special Soil Contamination Management Facility Sites properly. Stakeholders for the potentially contaminated sites should easily access and raise the soil contamination issues, and soil contamination investigation implemented by liable and profit environment (consulting) companies should be encouraged. Third, the soil contamination reporting system of SECA needs to change legally responsible. Further more, public announcement system showing soil quality of a site which exceeds a certain scale would be considerable. Fourth, liable environment (consulting) companies should legally execute Soil Environment Assessment of SECA.

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Modality of Heavy Metal Contamination of Soil in Military Rifle Shooting Range (소화기 사격장의 중금속 오염 양상)

  • Lee, Kwang-Lyeol;Hyun, Jae-Hyuk
    • Journal of Soil and Groundwater Environment
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    • v.21 no.3
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    • pp.58-63
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    • 2016
  • The study examined the level of heavy metal contamination by dividing military rifle shooting ranges into the three areas, i.e firing, trajectory, and target. The target area was found to be contaminated at a level higher (Cu 845 mg/kg, Pb 30,487 mg/kg) than the Worrisome Level of Soil Contamination (hereinafter referred to as the “Worrisome Level”) The trajectory area was predicted to be free from contamination, but it did indicate contamination although it was pretty much lower (Cu 23 mg/kg, Pb 99 mg/kg) than Worrisome Level. This is attributed to the contamination spread when rearranging the soil of the target area during the maintenance of the shooting range. The firing area was also predicted to be free from heavy metal contamination, but the results analyzed indicated a contamination higher (Cu 201 mg/kg, Pb 2,286 mg/kg) than Worrisome Level. This is attributed to the fragments of the broken bullet scattering due to the pressure generated as the bullet leaves the muzzle. An examination of heavy metal contamination in the discharge area as well as gutters to prevent the intrusion of rain water from perimeter revealed a high level of contamination (Cu 298 mg/kg, Pb 6,497 mg/kg), which makes it necessary to take measures.

Mapping Soil Contamination using QGIS (QGIS를 이용한 토양오염지도 작성)

  • Kim, Ji-Young;Bae, Yong-Soo;Park, Jin-Ho;Son, Yeong-Geum;Oh, Jo-Kyo
    • Journal of Environmental Health Sciences
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    • v.45 no.5
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    • pp.487-496
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    • 2019
  • Objective: The purpose of this study was to create soil contamination maps using QGIS (Quantum Geographic Information System) and suggest selection methods for soil pollution sources for preferential investigation in a soil contamination survey. Method: Data from soil contamination surveys over five years in Gyeonggi-do Province, South Korea (2013-2017) were used for making soil contamination maps and analyzing the density of survey points. By analyzing points exceeding the concern level of soil contamination, soil pollutant sources for priority management were identified and selection methods for preferred survey points were suggested through a study of the model area. Results: A soil contamination survey was conducted at 1,478 points over five years, with the largest number of surveys conducted in industrial complex and factory areas. Soil contamination maps for copper, zinc, nickel, lead, arsenic, fluoride, and total petroleum hydrocarbons were made, and most of the survey points were found to be below concern level 1 for soil contamination. The density of the survey points is similar to that of densely populated areas and factory areas. The analysis results of points exceeding the criteria showed that soil pollutant sources for priority management were areas where ore and scrap metals were used and stored, traffic-related facilities areas, industrial complex and factory areas, and areas associated with waste and recycling. According to the study of the model area, the preferred survey points were traffic-related facilities with 15 years or more since their construction and factories with a score of 10 or more for soil contamination risk. Conclusion: Soil contamination surveys should use GIS for even regional distribution of survey points and for the effective selection of preferred survey points. This study may be used as guidelines to select points for a soil contamination survey.

A Study on the Contamination of Photovoltaic Cells by Fine Dust in the Air (공기 중의 미세먼지에 의한 태양전지의 오염에 관한 연구)

  • HAN, JIN MOK;CHOI, SOOKWANG;KIM, SEWOONG;JUNG, YOUNGUAN
    • Transactions of the Korean hydrogen and new energy society
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    • v.29 no.3
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    • pp.292-298
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    • 2018
  • The contamination of photovoltaic (PV) cells reduces the incidence of sunlight and reduces the power generation output of PV cells. The main factor influencing the contamination of PV cells installed outdoors is the fine dust in the air, but the influence of temperature, humidity, rain and wind can be considered. In this paper, experiments on the contamination of PV cells according to the fine dust density, the temperature and humidity of air were investigated. As results of this study, the contamination area of PV cells increases with contamination time and cumulative fine dust density in the air. The contamination of PV cells increases when the temperature is low and the humidity is high. Also, as the contamination of PV cells is affected to the wind, the deviation of contamination area is happened.

An Assessment of the Heavy Metal Contamination of Sediment in Main Stream and Tributaries of the Han River in the Vicinity of Seoul (서울시 인근의 한강 본류 및 지류에 대한 하상 저질의 중금속오염 평가)

  • 노수미;이홍근
    • Journal of Environmental Health Sciences
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    • v.20 no.4
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    • pp.17-35
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    • 1994
  • This study was performed to investigate and assess the heavy metal contamination of sediment in main stream and tributaries of the Han-river in the vicinity of Seoul. Sediment were sampled at eight locations of main stream and eighteen locations of tributaries in the spring, summer, and fall in 1993. Six heavy metals of Cd, Cu, Pb, Zn, Cr, and Hg, were assessed. For an assessment of heavy metal contamination in sediment, the assessment method of Hakanson was modified to estimate for Han-river, then classification method of Muller in sediment quality was applied. For an assessment of contamination in each heavy metal, Contamination factor C$_f^i$ which was defined the ratio of concentration of i heavy metal in investigated location to background concentration of i heavy metal in uncontaminated upper area was used. The sediment quality in each heavymetal was classified as follows if C$_f^i$<1, Class I for Non contamination, if 1 < C$_f^i$ < 3, Class II for Low contamination, if 3< C$_f^i$ <6, Class III for Moderate contamination, if 6< C$_f^i$ <12, Class IV for Considerable contamination, and if C$_f^i$ > 12, Class V for High contamination.(abbreviation)

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Building a Classification Scheme of Soil and Groundwater Contamination Sources in Korea: 1. State-of-the-Art and Suggestions (토양.지하수오염원 분류체계 구축방안: 1. 국내외 현황 및 시사점)

  • An, Jeong-Yi;Shin, Kyung-Hee;Hwang, Sang-Il
    • Journal of Soil and Groundwater Environment
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    • v.15 no.6
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    • pp.64-71
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    • 2010
  • National inventory of soil and groundwater contamination is an efficient decision-making tool to identify and manage existing or potential contaminated sources and contaminants. It has been used as basic data for establishing the scheme of regulations and remediation plans of soil and groundwater contamination in developed countries. This study examined classification of existing or potential sources of soil and groundwater contamination from various countries to suggest implications that required for development of classification of soil and groundwater contamination sources in Korea. Each country has provided a list of currently or potentially contaminating activities or landuses and identified some of the potential contaminants related to those contamination sources. Consideration of sources which had not been mentioned or regarded as contamination sources before was suggested for Korea situation. In addition, it is necessary to compile a list of existing data and information as much as possible to develop a detailed and practical list of various contamination sources.

Effect of Yarn Characteristics on the Needle Contamination during Knitting Process

  • Koo, Young-Seok
    • Textile Coloration and Finishing
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    • v.22 no.1
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    • pp.8-13
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    • 2010
  • Needle contamination was investigated using a test rig simulated the knitting points in the knitting machine in relation with the characteristics of knitting yarn such as yarn type and moisture contents. When used open-end yarn compared with combed and carded ring-spun yarns, the needle contamination was significantly increased because of the higher friction between yarn and needle by the fly and other impurities. Also Lower moisture content of the yarns aggravated the needle contamination. In addition knitting yarn breakage was substantially influenced by the higher needle contamination.