• 제목/요약/키워드: Contamination of Surface

검색결과 937건 처리시간 0.03초

부산 석대 폐기물 매립지에서의 전기탐사 (Electrical Surveys at the Seokdae Waste Landfill of Pusan)

  • Kiehwa Lee;Jong-Ryeol Yoon
    • 대한지하수환경학회지
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    • 제4권4호
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    • pp.185-190
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    • 1997
  • 부산 석대 폐기물 매립지에서 1996년 7월중 전기비저항탐사를 실시하였다. 매립지 내부에서는 쌍극자탐사 4측선과 슐럼버져 수직탐사 7측점이 수행되었으며, 매립지 전방지역에서는 수직탐사 2측점이 수행되었다. 자료의 해석결과, 매립지 내부에서는 l0Ωm이하의 낮은 비저항값을 가지는 층이 지표하 50m 까지 나타났으며, D 블록의 경우는 다른 블록들보다 이러한 저비저항대가 약 2~10 m 정도 두껍게 나타났다. 이 지역의 기반암 심도와 매립고를 고려할 때, 매립지 내부에서는 침출수에 의한 기암의 오염은 진행되지 않았으나 풍화대는 오염된 것으로 판단된다. 그러나 A, B 블록에서 N$70^{\circ}$W의 주향을 가지는 소규모의 단층이 쌍극자탐사자료에 확인되어, 추후 기반암의 침출수오염 가능성을 배제할 수 없다. 또한 다른 블록들에 비하여 D 블록의 지충오염 정도가 가장 심한 것으로 나타났는데 이는 침출수의 주 유동방향이 D 블록을 향하고 있기 때문인 것으로 생각된다. 한편, 매립지 전방지역에서는 비저항자료에 의한 지층의 침출수오염 징후는 발견되지 않았다.

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Effects of contamination by either blood or a hemostatic agent on the shear bond strength of orthodontic buttons

  • Gungor, Ahmet Yalcin;Alkis, Huseyin;Turkkahraman, Hakan
    • 대한치과교정학회지
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    • 제43권2호
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    • pp.96-100
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    • 2013
  • Objective: To evaluate the effects of contamination by either blood or a hemostatic agent on the shear bond strength (SBS) of orthodontic buttons. Methods: We used 45 freshly extracted, non-carious, impacted third molars that were divided into 3 groups of 15. Each tooth was etched with 37% phosphoric acid gel for 30 s. Human blood or the blood stopper agent was applied to the tooth surface in groups I and II, respectively. Group III teeth were untreated (controls). Orthodontic buttons were bonded to the teeth using light-curing composite resin. After bonding, the SBS of the button was determined using a Universal testing machine. Any adhesive remaining after debonding was assessed and scored according to the modified adhesive remnant index (ARI). ANOVA with post-hoc Tukey's test was used to determine significant differences in SBS and Fisher's exact test, to determine significant differences in ARI scores among groups. Results: ANOVA indicated a significant difference between groups (p < 0.001). The highest SBS values were measured in group III ($10.73{\pm}0.96$ MPa). The SBS values for teeth in groups I and II were significantly lower than that of group III (p < 0.001). The lowest SBS values were observed in group I teeth ($4.17{\pm}1.11$ MPa) (p < 0.001). Conclusions: Contamination of tooth surfaces with either blood or hemostatic agent significantly decreased the SBS of orthodontic buttons. When the contamination risk is high, it is recommended to use the blood stopper agent when bonding orthodontic buttons on impacted teeth.

병원감염 예방을 위한 Film Cassette의 자외선 소독 효과 (Disinfection Efficacy of an Ultraviolet Light on Film Cassettes for Preventive of the Nosocomial Infection)

  • 권대철;전용웅;조암
    • 대한방사선기술학회지:방사선기술과학
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    • 제24권1호
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    • pp.27-32
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    • 2001
  • The bacteria infection on film cassette contact surface was examined at the diagnostic radiology department of the S. hospital. The objective of this study was to assess the contamination level on film cassette contact surface as a predictor of patient prevention from nosocomial infection and for improvement of the hospital environment. The laboratory result was identified non-pathologic bacterial in the five different cassette size of the contact surface. Film cassettes were exposed to ultraviolet light for 1, 2 and 3 minutes. Ultraviolet light disinfection is proven suitable for bacteria. The study concludes that presence of a bacterial infection will prevent a using antiseptic technique on film cassette contact surface. In addition education of nosocomial infection for radiographers will be required. In conclusion, ultraviolet is considered effective to irradate bacteria. Additionally, two minutes are required to sterilize film cassettes.

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코로나방전선 표면 산화에 따른 오존발생량의 경시특성 (Time Dependant Ozone Generation due to Oxidation of the Surface of Corona Discharge Wires)

  • 정성진;박승록;문재덕
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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    • pp.22-25
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    • 2000
  • Time dependent ozone generation characteristics of some oxide layers grown by ozone on the surface of corona discharge wires have been investigated experimentally in air ambience. Four wires of stainless steel, iron, silver and copper were used for the corona discharge wire of an ozone generator. And the effect of the metal oxide layers on ozone generation was studied and the contamination morphology of each layers was characterized. With the SEM images and the EDS spectra, it was found that all the surface of the corona wire were oxidized by the generated ozone and contaminated by airborne particles through the gradient force. As a result, the morphology and the electrical property of metal oxide layer grown on corona wire surface influenced on ozone generation characteristics i.e. discharge mechanisms.

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실험계획법을 이용한 반도체용 대구경 스테인레스관의 내경 가공에 관한 연구 (A study on the Internal machining of a large-diameter Stainless pipe for Semiconductor Using Experimental Design Method)

  • 김창근;이은상
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 추계학술대회
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    • pp.71-76
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    • 2003
  • This paper describes the characteristic of a large-diameter pipe to obtain smooth surface using Electropolishing after grinding using a non-woven fabric. Grinding using a non-woven fabric is possible under lower load and fine effect comparing with Wheel grinding. Also, the ion from the surface of the metal is eliminated by means of an electrical potential and current in Electropolishing. Electropolishing is used for leveling the surface, improving the physical appearance of the part, promoting corrosion properties and reducing contamination and adhesion of the surface. Therefore, the aim of the present study is to investigate the internal machining of a large-diameter pipe for semiconductor using experimental design method.

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IMAGING SPECTROMETRY FOR DETECTING FECES AND INGESTA ON POULTRY CARCASSES

  • Park, Bo-Soon;William R.Windham;Kurt C.Lawrence;Smith, Douglas-P
    • 한국근적외분광분석학회:학술대회논문집
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    • 한국근적외분광분석학회 2001년도 NIR-2001
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    • pp.3106-3106
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    • 2001
  • Imaging spectrometry or hyperspectral imaging is a recent development that makes possible quantitative and qualitative measurement for food quality and safety. This paper presents the research results that a hyperspectral imaging system can be used effectively for detecting fecal (from duodenum, cecum, and colon) and ingesta contamination on poultry carcasses from the different feed meals (wheat, mile, and corn with soybean) for poultry safety inspection. A hyperspectral imaging system has been developed and tested for the identification of fecal and ingesta surface contamination on poultry carcasses. Hypercube image data including both spectral and spatial domains between 430 and 900 nm were acquired from poultry carcasses with fecal and ingesta contamination. A transportable hyperspectral imaging system including fiber optically fabricated line lights, motorized lens control for line scans, and hypercube image data from contaminated carcasses with different feeds are presented. Calibration method of a hyperspectral imaging system is demonstrated using different lighting sources and reflectance panels. Principal Component and Minimum Noise Fraction transformations will be discussed to characterize hyperspectral images and further image processing algorithms such as image band ratio of dual-wavelength images and its histogram stretching with thresholding process will be demonstrated to identify fecal and ingesta materials on poultry carcasses. This algorithm could be further applied for real-time classification of fecal and ingesta contamination on poultry carcasses in the poultry processing line.

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Effect of ultra - violet laser treatment on multi - wall carbon nanotube surface

  • Kim, Jun-Sik;Ahn, Kyoung-Soo;Lee, Chang-Hyo;Kim, Chae-Ok;Hong, Jin-Pyo
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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    • pp.689-691
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    • 2002
  • Well-aligned multi-wall carbon nanotubes (MWCNTs) have been grown on both Coming glass and silicon substrates at about 400 $^{\circ}C$ by a modified plasma - enhanced chemical vapor deposition system. We have investigated laser irradiation effect on carbon nanotube surface by using an ultra - violet laser. The laser operated to modify structural defect of was carbon nanotube and to ablate possible contamination of carbon nanotube surface. The morphology and surface transformation of MWCNTs as analyzed by a SEM. In addition, the field emission measurement was also carried out in a vacuum chamber with a $10^{-7}$ Torr base pressure by applying bias voltages up to 1000V.

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Microbial contamination including Vibrio cholerae in fishery auction markets in West Sea, South Korea

  • Choi, Yukyung;Lee, Yewon;Lee, Soomin;Kim, Sejeong;Lee, Jeeyeon;Ha, Jimyeong;Oh, Hyemin;Shin, Il-Shik;Yoon, Yohan
    • Fisheries and Aquatic Sciences
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    • 제22권11호
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    • pp.26.1-26.7
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    • 2019
  • Background: The monitoring of pathogens of fishery auction markets is important to obtain safe fishery products regarding hygiene and sanitation. In this study, aerobic, coliform, Escherichia coli, and Vibrio cholerae were monitored in the fishery products and environmental samples obtained from fishery auction markets. Methods: The fishery products (flounder, octopus, skate, rock cod, sea bass, snail, monkfish, flatfish, comb pen shell, corb shell, conger eel, hairtail, croaker, and pilchard) were placed in filter bags, and the environmental samples (samples from the water tanks at the fishery auction markets, seawater from the fishery distribution vehicles, ice from wooden or plastic boxes, and surface samples from wooden and plastic boxes used for fish storage) were collected. Aerobic bacteria, E. coli, and coliform in the samples were enumerated on aerobic count plates and E. coli/coliform count plates, respectively. For V. cholerae O1 and V. cholerae non-O1 quantification, most probable number (MPN)-PCR analysis was performed. Results: Aerobic and coliform bacteria were detected in most samples, but E. coli was not detected. Wooden boxes were contaminated with high levels of aerobic and coliform bacteria in all seasons (spring, summer, and fall). During fall, V. cholerae non-O1 were detected in snails, hairtails, croakers, flatfishes, pilchards, plastic boxes, and water samples. Conclusions: These results indicate an increased prevalence of V. cholerae contamination in fishery products in fall, including food contact samples, which can be vehicles for cross-contamination.

대체냉각 기술을 이용한 환경친화 연삭가공 기술 (A Study on the Grinding Characteristics According to Cooling Methods)

  • 이석우;최헌종;허남환;이종항
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.962-967
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    • 2003
  • Recently, environmental pollution has become a serious problem in industry, and many researches have been done in order to preserve the environment. The coolant, which promotes lubrication, cooling and penetration, contains chlorine, sulfur and phosphorus to improve the machining efficiency. These additives, which move around into the air during machining, pollute working. Therefore, many researches on how to reduce the amount of coolant during machining have been carried out. However, to reduce even small amount of coolant causes high temperature of a workpiece and it brings thermal defects. In this study, the experiments of wet & dry grinding using cooling methods (using coolant only, mist and compressed cold air only) are performed to solve the problem of environmental contamination and to get a better surface integrity of a workpiece by comparing surface roughness, roundness and residual stress.

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Salt fog 내에서 옥외용 고분자 절연물의 내오손 성능 변화 (The Change of Contamination Performance of Polymeric Insulators for Outdoor Use)

  • 김정호;문중섭;박용판;김동명;원호상
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 추계학술대회 논문집
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    • pp.505-508
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    • 1999
  • In this study, weight loss, ESDD, surface conductivity and leakage current were measured at the different saline solutions by salt fog method. The magnitude of leakage current was higher at higher conductivity of 2 S/m saline water, but weight loss ESDD and surface conductivity which are indices of degradation were lower. This is considered that the current includes mainly ohmic component which doesn\`t contribute to surface degradation. In addition, it is shown that FFT could be useful in measuring initial transition from hydrophobic to hydrophilic surface.

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