• 한국산업보건학회지
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• 제8권2호
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• pp.186-195
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• 1998

The objective of this study was to determine if MWF(metalworking fluids) mass sampled on PVC filter lose during flowing airstream and desiccating and to present direction to correct the underestimated MWF mass. Flowing airstream caused MWF sampled on PVC filter to be breakthrough and lost. Loss of MWF on PVC filter increased in proportion to time of flowing airstream. Meanwhile, loss of MWF was observed during desiccating without flowing airstream. Vapor pressure of MWF is so low that it would not normally be thought to evaporate. However, MWF mist sampled on PVC filter has so great a surface area that loss by flowing airstream and evaporation can be appreciable. Loss between fresh and used MWF was also different. Those study results mean that NIOSH method(#0500 method) to take airborne MWF mist with PVC filter is not valid. Media to sample airborne MWF accurately still have not been introduced. It seems to be needed to estimate how much MWF on PVC filter may be lost during sampling. Regression model between sampling time including 1 day desiccating and total loss of MWF was "Total loss(%)=18.4%+0.06 sampling time(p=0.000, r2=49.6%)". This model help correct MWF lost when one measures airborne MWF using NIOSH # 0500 method.

• 분석과학
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• 제14권5호
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• pp.451-457
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• 2001

절삭유(Metalworking Fludis, MWF) 노출로 인한 건강상의 장애는 암, 호흡기질환, 피부질환이다. MWF는 20여가지 이상의 화학물질이 혼합된 고분자의 화합물로서 상온에서 쉽게 증발되지 않는다. 이러한 특성으로 공기 중 MWF미스트의 측정과 분석은 PVC필터를 이용한 중량법이 국제적으로 공인되어 이용되고 있다. 그러나 사업장에서 MWF는 사용과정에서 분산되면 표면적이 커지고 증발하기 쉬운 상태로 된다. 본 연구는 실험실에서 MWF미스트 발생장치를 제작하여 MWF미스트가 필터에 채취되고 분석되는 과정에서 손실되는 양과 원인을 정량적으로 분석하였다. 즉 챔버에서 MWF가 채취된 PVC필터를 깨끗한 공기로 일정시간동안(10 ~ 240 분) 접촉하고 건조하여 각각의 과정(공기접촉, 건조기간)에서의 손실을 평가하였다. 공기와의 접촉 10분 후에 손실된 MWF양은 원래양의 12.4% - 21.8%였다. 전과정에서 손실된 양의 53.3%가 공기의 접촉초기에 일어나는 것을 확인하였다. PVC필터에 채취된 MWF의 손실은 건조과정에서 일어난 것을 확인하였다. PVC필터에 채취된 MWF의 손실에 영향을 미치는 요인을 분석하기 위한 다중회귀분석에서 MWF의 특성(사용중인 것과 사용하지 않는 것)이 유의한 예측변수였다. 이 연구 결과에 따르면, 국제적으로 공인된 증량법에 의한 공기중 MWF측정은 과소평가되는 것으로 판단된다.

• 한국산업보건학회지
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• 제7권2호
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• pp.171-180
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• 1997

The objectives of this study were both 10 discuss the sampling method for airborne metalworking fluids(MWF)' mist and 10 suggest measures to minimize worker's exposure to carcinogen contained in metalworking fluids. In order to measure airborne MWF mist, it seems to be appropriate to use NIOSH Method #0500(filler weight) rather than NIOSH Method # 5026(analysis by FTIR). Because MWF mist on PVC filter evaporated and migrated during sampling, worker's exposure to MWF could be underestimated. So, when evaluating worker's exposure to MWF mist, other environmental conditions also must be considered. Enclosure and local exhaust ventilation system seems to he the most effective measure and must be constructed with process facility. In order to control worker exposure to carcinogens contained in MWF, distillation type and condition for crude oil, PAH concentration in MWF, and viscosity index of MWF must legally be described.

• 한국산업보건학회지
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• 제17권1호
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• pp.1-12
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• 2007

We have reviewed all cases and epidemiological studies that have reported the association between worker's exposure to metalworking fluids(MWF) and non-malignant respiratory diseases. The followings are main conclusions we critically reviewed. Exposure to MWF was believed to be significantly related to the risk of cough and phlegm. Relative risk caused by straight MWF was found to be higher in exposure to straight MWF than water-soluble MWF. We also found that exposure to water-soluble MWF significantly caused hypersensitivity pneumonitis (HP) and occupational asthma. The main culprits that cause the development of HP and asthma are believed to be microbes contaminated in MWF, ethanolamine and biocides. HP and asthma could be developed at even exposure to lower than $0.5mg/m^3$, exposure level recommended by NIOSH. Most epidemiological studies have reported that relationship between chronic bronchitis and exposure to MWF was significant. Although there were several studies that suggested the significant association between exposure to MWF and the development of rhinitis and sinusitis, we could not conclude the causal relationship because of lack of evidences.

• 한국정밀공학회지
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• 제20권1호
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• pp.50-62
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• 2003

Exposure to metalworking fluids (MWFs) has significantly been associated with cancer developed in multi-organs, respiratory diseases and skin diseases. Several carcinogens to humans or animals are contained in MWFs. They have been reported to be mineral oils, polynuclear aromatic hydrocarbons (PAHs), formaldehyde and N-nitrosodiethanolamine (NDELA). The great hazards of MWF have forced the advanced country including United States to regulate carcinogens contained in MWF. In 2001, American Conference of Governmental Industrial Hygienists (ACGIHs) regarded MWF mist as suspected carcinogen to human (A2) and added it to “Notice of Intended Change (NIC)” list of 2001. In spite of the fact that much MWF has widely been used in many industries using machines, Korea has no legal actions for management of MWF. What is worse, even toxicity such as Carcinogenicity has not been reported. KS (Korean Standards) lists 7 advices of MWF but it does net state the hazards to health. It is very hard to control or minimize worker's exposure to MWF containing many carcinogens. Prier to the introduction of MWF to workplace, it is the most effective measure to regulate carcinogens below a certain level. Regulation on the content of PAH seems to be necessary because less amount of PAH in mineral oils improves the quality of MWF. Also, addition of nitrosating groups to MWF should be prohibited to minimize worker's exposure to NDELA. Employers and manufacturers should indicate the Carcinogenicity of all carcinogens in MWFs in Material Safety Data Sheets (MSDS) in order fer workers to recognize Carcinogenicity. Legal actions have to be taken to protect workers from health hazards due to exposure to MWF by further investigation on MWF.

• 한국산업보건학회지
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• 제15권3호
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• pp.270-276
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• 2005

This study was conducted to examine whether a specific synthetic metalworking fluid (MWF), "A", in use for 10 months without replacement, displayed microbial resistance and to identify the additives associated with the control of microbial growth. Three synthetic MWF products ("A", "B", and "C") were studied every week for two months. Microbial deterioration of the fluids was assessed through evaluation by endotoxin, bacteria and fungi levels in the MWFs. In addition, formaldehyde, boron, ethanolamine, and copper levels were also studied to determine whether they influence microbial growth in water-based MWFs. Throughout the entire study in the sump where MWF "A" was used, bacteria counts were lower than 103 CFU/mL, and endotoxins never exceeded 103 EU/mL. These levels were significantly lower than levels observed in sumps badly deteriorated with microbes. Boron levels in MWF "A" ranged from 91.7 to 129.6 ppm, which was significantly higher than boron levels found in other MWF products. The total level of ethanolamine (EA) in MWF "A" ranged from 35,595 to 57,857 ppm (average 40,903 ppm), which was over ten times higher than that found in other MWFs. Monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) concentrations in MWF "A" were also significantly higher than seen in other MWFs. However, although EA and boron might improve anti-microbial performance, their abuse can pose a serious risk to workers who handle MWFs. From an industrial hygiene perspective, our study results stress that the positive synergistic effect of boron and EA in reducing microbial activity in MWF must be balanced with the potentially negative health effects of such additives. Our study also addresses the disadvantage of failing to comprehensively report MWF additives on Material Safety Data Sheets (MSDS). Future research in MWF formulation is needed to find the best level of EA and boron for achieving optimal synergistic anti-microbial effects while minimizing employee health hazards.

• 대한원격탐사학회지
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• 제28권5호
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• pp.561-571
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• 2012

변조전달함수(MTF; Modulation Transfer Function)는 광학영상의 성능을 평가하는 중요한 품질 요소 중 하나이다. 영상의 MTF 증진을 위해 영상 복원이 필요하나, 이 과정은 대표적인 부적합문제(ill-posed problem)의 하나로 특정한 해를 갖지 않는다. 영상 복원을 위한 필터에는 역 필터(IF; Inverse Filter), 의사 역 필터(PIF; Pseudo Inverse Filter), Wiener Filter(WF) 등이 있다. 이들 중 가장 일반적으로 사용되고 있는 WF는 촬영된 영상 내에서 영상과 잡음을 정확히 구분하기 어렵다는 한계를 가지고 있다. 본 논문에서는 Modified Wiener Filter(MWF)를 사용하여 부적절 문제를 풀 수 있도록 문제를 정규화 하였으며, 정규화 변수(regularization parameter)의 값을 찾기 위한 방법으로 L-곡선(L-curve)을 사용하였다. MWF의 검증을 위해 Dubaisat-1 위성의 영상을 의사 역 필터(PIF), Wiener Filter(WF), MWF로 영상 복원을 수행하였다. 복원 결과, MWF를 사용했을 때가 PIF를 사용했을 때의 결과에 비해 20.93%, WF를 사용했을 때의 결과에 비해 10.85% 더 향상된 MTF를 얻을 수 있었다.

• 한국산업보건학회지
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• 제8권1호
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• pp.67-75
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• 1998

The objectives of this study were both to evaluate the level and correlations of hazardous agents and to suggest measures to control industrial hygiene problems caused by using water-soluble metalworking f1uids(MWF). Geometric mean of formaldehyde(0.039 ppm) was higher than criteria of NIOSH(0.016ppm). Formaldehyde, originally existed in the biocide, is released and used to kill microbes in soluble MWF. Microbe concentrations were above $10^4No./mL$ in 14 MWF tanks among 20 tanks surveyed. Nitrosamines that is formed by reaction of nitrosating group and amines was detected to $18.4-47.1{\mu}g/m^3$. Formaldehyde concentration was low when microbes were abundant(r=-0.67, p=0.011), and high when open tank area was wide(r=0.75. p=0.012). The significant relationship between pH and microbes(r=-0.76. p=0.003) was also observed. The predominant bacteria species in MWF were Pseudomonas spp., Bacillus spp., Comamonas testosteroni, Acinetobacter haemolyticus, Bordertella bronchiseptica in order. Therefore, hazardous agents emitted by using water-soluble MWF seems to be correlated microbial growth. In order to minimize worker's exposure to several hazardous agents by an water-soluble MWF and to increase productivity, microbial growth must be controlled to the lowest level as possible. Administrative control as well as engineering control must comprehensively be applied to control microbe's growth in water-soluble MWF.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2004년도 International Conference Global Environmental Problems and their Health Consequences
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• pp.217-222
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• 2004

This study was conducted to estimate if the level of several chemical ingredients including alkanolamines or ethanolamines (EA) examined in the specific synthetic metalworking fluid (MWF) ‘A’ can cause anti-microbial activity and health effect. Three water-based MWF products (‘A’, ‘B’, and ‘C’) were studied every week for two months. Chemical ingredients such as formaldehyde, boron, EA, and copper were examined. In the sump where MWF ‘A’ was used, not only the total level of EA, monoethanolamine(MEA), diethanolamine(DEA) and triethanolamine(TEA), but also boron level were significantly higher than those of the other MWFs. ANOVA statistical tests indicated that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF ‘A’ were significantly higher than those in other MWF types. Correlation tests also found that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF ‘A’ are significantly correlated. We suggested the assumptions that excessive concentrations of EA, and borate at a high pH level, may cause anti-microbial resistance synergically. To demonstrate this assumption, additional study is needed to examine the relationship between the levels of microbes and excessive concentrations of EA, and borate at a high pH level.

• KSTLE International Journal
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• 제4권2호
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• pp.52-55
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• 2003

This study was conducted to estimate if the level of several chemical ingredients including alkanolamines or ethanolamines (EA) examined in the specific synthetic metalworking fluid (MWF) "A" can cause anti-microbial activity and health effect. Three water-based MWF products ("A", "B", and "C") were studied every week for two months (from June 1, 2002 to July 30, 2002). Chemical ingredients such as formaldehyde, boron, EA, and copper were examined. In the sump where MWF "A" was used, not only the total level of EA, monoethanolamine(MEA), diethanolamine(DEA) and triethanolamine(TEA), but also boron level were significantly higher than those of the other MWFs. ANOVA statistical tests indicated that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF "A" were significantly higher than those in other MWF types. Correlation tests also found that levels of pH, alkalinity, boron, MEA, DEA and TEA in MWF "A" are significantly correlated. We suggested the assumptions that excessive concentrations of EA, and borate at a high pH level, may cause anti-microbial resistance synergically. To demonstrate this assumption, additional study is needed to examine the relationship between the levels of microbes and excessive concentrations of EA, and borate at a high pH level.