• 한국식품위생안전성학회지
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• 제8권4호
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• pp.241-249
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• 1993

This study was performed to investigate the remainity of synthetic surfactant (LAS) by HPLC and the microbial contamination on stainless steel dishes. For the maintenance and the improvement of school lunch program's safety, the remainity of synthetic surfactants (LAS) on stainless steel dishes washed with auto dishwasher was investigated by HPLC, and the microbial contamination on same dishes was surveyed. The results were as follows: (1) The remainity of synthetic surfactant (LAS) a) The residue of LAS was very small because of the repeated washing of dishes by strong pressurized water. b) The remainity range of LAS on stainless steel dishes was 2.1~7.2 $\mu\textrm{g}$/dish. The remainity of general surfactants was higher in cold water then warm water. The amount of residual general surfatants was 5.95 $\mu\textrm{g}$/dish in cold water, and 2.95 $\mu\textrm{g}$/dish in warm water. There was no difference of the remainity of special surfactants by water temperature. The amount of residual surfactants was 3.9 $\mu\textrm{g}$/dish. c) There was no difference of residue amount by washing times. (2) The microbial contamination after washing with general surfactants. 1) The mean MPN of E. coli was 203(53~345) on 1 hr, 19(6~28) on 2 hrs, in cold water, and 1100(only 1 dish of 1 school) on 1 hr, 24(6~42) on 2hrs. 2) After washing with general surgactants the mean of contamination by general microbials was 956(25~2300)on 1 hr, 694(45~2500) on 2 hrs. in cold water and 803(5~2300) on 1 hr, 671(5~2500)on 2 hrs. After washing with special surfactants the mean of contamination by general microbials was 788(136~2900) on 1 hr, 1122(15~3000) on 2 hrs, in cold water and 537(5~2000) on 1 hr, 88(15~150) on 2 hrs in warm water. (3) Like the results of this study, the good washing methods of stainless steel dishes for school luch program were as follows. First, for washing stainless steel dishes, the use of special surfactants was recommended at 30~4$0^{\circ}C$ water. Second, at 7$0^{\circ}C$ water, the rinsing of dishes was recommended. Third, the final rinsing at 8$0^{\circ}C$ combined with simple disinfection and dry was recommended.

• 한국식품위생안전성학회지
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• 제28권4호
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• pp.319-323
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• 2013

본 연구는 시중에 유통되고 있는 인삼 및 인삼 제품류의 미생물 오염실태를 조사하고자 수행하였다. 충남 금산과 진주 인근지역에서 유통되고 있는 인삼 및 인삼 제품류 81점에 대해 미생물 오염도를 조사한 결과 일반세균과 대장균군은 수삼이 3.19~7.02 log CFU/g로 오염도가 가장 높았고, 백삼에서는 0.25~7.31 log CFU/g, 홍삼에서는 0~2.89 log CFU/g, 홍삼음료에서는 0~1.70 log CFU/mL 범위의 오염도를 나타내었다. 병원성 미생물은 홍삼음료를 제외한 수삼, 백삼 및 홍삼에서 B. cereus가 검출되었다. 그 오염 수준은 수삼의 경우 91.9%(34/37)에서 2.41 log CFU/g 수준으로 검출되었고, 백삼은 53.3%(8/15)에서 0.98 log CFU/g, 홍삼은 13.3%(2/15)에서 0.50 log CFU/g 수준으로 검출되었다. 곰팡이의 경우 수삼에서만 0.72~5.54 log CFU/g범위로 검출되었고, 나머지 백삼(73.3%), 수삼(73.3%), 홍삼음료(21.4%)는 1 log CFU/g or mL 이하의 매우 낮은 수준의 오염도를 나타내었다. 유통 중인 인삼 및 인삼 제품류의 미생물 오염도는 대체적으로 양호한 수준이었으나 일부 제품은 인삼류 제품 검사기준을 초과한 경우도 존재하기 때문에 미생물 오염 방지를 위한 위생관리에 주의를 기울일 필요가 있는 것으로 판단된다.

• 지질공학
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• 제15권1호
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• pp.29-39
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• 2005

지반오염을 조사하기 위해서는 시추작업을 통하여 시료를 채취하는 방법이 일반적이지만, 실시간으로 원위치에서 다양한 오염물질들의 오염 도 변화를 체계적으로 모니터링 하는 것은 대단히 어렵다. 본 연구에서는 frequency Domain Reflectometry (FDR) 장비를 고안하여 지반의 유류오염을 파악하기 위한 유전율 측정법의 실험적 접근을 시도하였다. 구체적으로 포화 및 불포화 매질에 대한 유류 오염도 측정 및 체적함수비 (θ/sub w/)와 체적 유류비 ( θ/sub al/)의 관계에서 유전율 상수 반응에 따른 매질의 유류 오염도 등의 측정 가능성을 실내 시험을 통해 검토하였다. 뿐만 아니라 실내 칼럼 시험을 수행하여 포화 매질 내에서 유류 거동 특성을 각기 설치된 FDR 측정 센서를 이용해 모니터링하여 포화 매질의 유효공극률과 유류 잔류비를 측정하였다. 그 결과 초기 공극률 0.40으로 제작된 포화 매질의 유효공극률은 약 0.35로 공극률 대비 약 87.5% 범위내에 존재함을 알 수 있었으며, 유류 잔류비는 약 62.5% 정도로 매우 높게 나타났다.

• 한국축산식품학회지
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• 제28권5호
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• pp.562-566
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• 2008

본 연구에서는 포장돈육 가공공정에서 교차오염의 정도를 알아보기 위하여 실제 돈육 가공공정에서 돈육과 빈번하게 접촉하는 작업자의 손(polyethylene glove 착용, 면장갑 착용, 맨손) 및 작업도구(칼, 도마)를 대상으로 각각에 대하여 Salmonella spp.의 상호 교차오염 전이율을 분석하였다. 오염된 돈육에서 작업자로의 전이율은 면장갑이 38.80%로 가장 높았고, 다음이 PG 3.11%,맨손 1.35% 순으로 나타났다. 특히, 면장갑의 경우 면 장갑으로 전이된 균이 다시 맨손으로의 재오염 전이(0.07%)가 이루어지는 것으로 나타났으며, 오염된 돈육에서 칼과 도마로의 전이율은 0.20-1.99%이다. 반대로 오염된 작업자로부터 돈육 및 기구로의 전이율은 0.0015-0.21%로 전체적으로 오염된 돈육으로부터의 작업자의 손과 기구로의 전이보다 상당히 낮은 수준으로 전이되었다. 따라서 PG 착용이 작업공정에서의 교차오염을 줄이거나 예방하는 효과를 얻을 수 있는 것으로 파악되었다. 축산물 작업공정에서의 교차오염은 원료육에서 손 또는 장갑, 도마, 칼 등으로 오염이 전이되고 이들이 다시 돈육을 오염시킬 수 있으므로, 안전한 식품생산을 위해서는 이러한 교차오염의 연속성을 차단하는 것이 무엇보다 중요함을 확인하였다.

• Computers and Concrete
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• 제34권1호
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• pp.49-61
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• 2024

The present study concerns a removal of chloride ions and structural behaviour of concrete beam at electrochemical chloride extraction (ECE). The electrochemical properties included 1000 mA/m2 current density for 2, 4 and 8 weeks. It was found that an increase in the duration of ECE resulted in an increase in the extraction rate of chlorides, in the range of 35-85%, irrespective of chloride contamination. In structural behaviour, the strength and maximum bending moment of specimen was always lowered by ECE. Moreover, the flexural rigidity and bending stiffness were reduced by the loss of effective cross-section area in the linear elastic range. Simultaneously, the inertia moment was substantially subjected to 70% loss of the cross-section by the tensile strain at the condition of the failure. However, a lower rate of the inertia moment reduction was achieved by ECE, implying the higher resistance to the cracking, but the higher risk of deformation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.38-43
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• 2002

A series of tests were performed to investigate the effects of pH and contamination level on cation exchange capacity and zeta potential in kaolinite loaded with lead. Test results show that cation exchange capacity of kaolinite is found to be in the range from 4 to 20meq/100g and it increased with increasing pH up to the converged number about 20meq/100g over pH 8. And then CEC has a tendency to reduce and converge to zero with increasing the concentration of Pb in the kaolinite surface. Moreover, zeta potential of kaolinite contaminated with lead is found to be in the range from -10 to 5mV, and zero point of charge is measured at about pH 3.5. Zeta potential of kaolinite contaminated with lead decreases with increasing pH values and decreasing Pb concentration of kaolinite.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.553-557
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• 2013

The stretching vibration of OH of ice Ih is studied by Car-Parrinello molecular dynamics in regarding the effect of mixed H/D contamination while the vibrational spectrum is considered by velocity-velocity autocorrelations of the sampled ensemble. When hydrogen atoms are immersed randomly into the deuterated ice, a typical vibrational frequency of OH stretching mode is observed to be similar to that from the pure $H_2O$ ice. When focusing on the correlation of isolated neighboring OH stretching, a narrower and blue shifted peak is observed at the high frequency range as a result of the screening from the complex many body correlations by $D_2O$ environment. It is also specifically related to the symmetric intermolecular correlations between neighboring OH stretching modes. More enhanced high frequency range can be explained by the expansion of such two body correlations to collective many body correlations among all possible OH stretching modes. This contribution becomes important when it involves in chemical interactions via excitation of such vibrational states.

• 농촌의학ㆍ지역보건
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• 제18권2호
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• pp.153-160
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• 1993

Health complaints among vinylhouse workers in Sungjoo county, Kyungpook province led to the investigation of heavy metal levels of air, soil and humans as well as physical conditions of the vinylhouse. The average temperature and humidity inside the vinylhouse were 8 higher and 10% point lower, respectively, as compared to the outside. While discomfort index(D. I.) outside was pleasant level(69.2), D. I. inside was 82 at which point 100% of people feels discomfort. Cadmium concentration of soils inside the vinylhouse(0.116 mg/kg) was 1.8 times higher than the soils outside. Arsenic concentration of soils inside the vinylhouse(4.882 mg/kg) was only slightly higher than the soils outside(4.182 ng/kg). However, both heavy metal concentrations detected in soils inside or outside the vinylhouse were within the normal range. Analysis of 10 air samples taken inside the vinylhouse showed that only one sample had a cadmium concentration above the detectable level and the rest of samples were below the detectable levels. While there were no difference of arsenic concentrations in urine between male and female, cadmium concentrations in urine samples of female (3.31 ug/l) was slightly higher than male(2.38 ug/l). Age-dependent increases of cadmium concentrations in urine samples were also observed. However, there was no concentration difference of these heavy metals in urine between vinylhouse workers and non-vinylhouse workers. Urine concentrations of cadmium and arsenic detected from vinylhouse workers or non-vinylhouse workers were within the normal range. The present study represents a first attempt to evaluate physical and environmental risk factors of the vinylhouse affecting the vinylhouse farmer's health. The study revealed that, while physical conditions of the vinylhouse such as temperature and humidity are the possible factors associated with the farmer's complaints, environmental contamination as judged from heavy metal levels in soil, air and humans is not a risk factor contributing to the vinylhouse farmer's health problem.

• 분석과학
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• 제16권3호
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• pp.232-239
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• 2003

청주시 석남천 유역의 4개 지점, 미호천 유역의 1개 지점, 석남천과 미호천 합류지역의 1개 지점 등 6개 지점을 기준지점으로 택하고, 각 지점의 상층, 중층, 하층에서 침전물을 채취하여 조사용 시료를 제작하였다. 한국원자력연구소의 연구용 원자로(HANARO)의 중성자 선을 이용한 중성자 방사화 분석법으로 원소함량을 분석하였다. 미국 표준연구원(NIST)의 인증표준물질을 이용하여 시료 중의 30 개 원소들의 함량을 비교법으로 분석하였다. 그 분석 결과로부터 하천오염원지역에서 하류로 이어지는 지역의 침전물 오염도분포조사 및 예측시 오염물질의 원소비중과 유속을 고려해야 하며 하천침전물의 함량분석을 위한 시료를 채취할 때 시료의 지역적 대표성을 확립하기 위해서는 원소의 비중과 유속 등을 고려하여 수직적 범위를 정할 필요가 있음을 알았다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제23권4호
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• pp.48-59
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• 2018

Beryllium (Be), cobalt (Co), thallium (Tl) and vanadium (V) are candidates of 21 priority soil pollutants in Korea. The distribution of their concentration in soils from three contamination sources including industrial, roadside and mining areas was investigated. Concentrations of the metals were evaluated quantitatively using pollution indices and the fractionation of metals was conducted using modified SM&T (Standards Measurements and Testing programme) sequential extraction. Concentrations of the metals for all samples from industrial and roadside soils were within the range of natural background levels, while some of Be in soils from abandoned mines exceeded that the range. Enrichment Factor (EF) and Nemerow Integrated Pollution Index (NIPI) for Be, Co, Tl and V showed that there are effects or possibilities of anthropogenic activities. Pollution Load Index (PLI) analyses indicated all investigated sites needed further monitoring. The results of sequential extractions indicated mobile fractions (F1+F2) of Be, Tl and V were below 30% except some of Co in soil, which implies their low mobility to neighboring environment media. Variable tools like sequential extraction, comparison with background/actual concentration and pollution indices, as well as aqua regia extraction should be considered when evaluating Be, Co, Tl, V in soil.