• 한국응용과학기술학회지
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• 제26권1호
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• pp.69-73
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• 2009

Copper alloy metal fiber was incorporated into the conventional water-soluble metal working fluids to increase the antimicrobial activity. Fluid treated by copper alloy metal fiber is shown that bacteria is disappeared whereas that untreated metal fiber is increased bacteria as increasing the life time. When the electrochemical potential of Cu/Zn ion is -268mV, radicals with molecular oxygen are easily made. Especially, hydroperoxide radical shows strong toxicity to the strains, leading to the conformational change of plasma membrane. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.

• 한국산업보건학회지
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• 제22권4호
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• pp.284-292
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• 2012

Objectives: The objective of this study was to investigate the relations between the bacterial concentration and the environmental factors in the water soluble metal working fluids at factories. Methods: The bacterial concentrations for airborne and fluid samples of 7 factories were quantified during the summer season. And we statistically analysed the relations between the bacterial concentrations and the factors such as temperature, relative humidity, usage quantity, mixing ratio and exchange interval. Results: The geometric mean levels of the airborne bacterial concentrations were 79.1(range : N.D.~686) $CFU/m^{3}$ and 68.1(range: N.D.~919) $CFU/m^{3}$ in the process and outdoor. The airborne bacterial concentrations showed no statistical difference by process, usage quantity, mixing ratio and exchange interval. The airborne bacterial concentrations had negatively weak correlations with air temperature and relative air humidity(p<0.05). The bacterial concentrations and pH showed significantly negative correlations in the fluids(p<0.05). And the airborne bacterial concentrations in factories and those in metal working fluids showed no statistical relationship. Conclusions: In the water soluble metal working fluids using factories, the airborne bacterial concentrations of the process were related to those of the outdoor and environmental factors, rather than the onsite contaminated metal working fluids.

• 한국응용과학기술학회지
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• 제24권3호
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• pp.233-237
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• 2007

This study is focused on the possibility of copper alloy metal fiber for an antimicrobial activity in the water soluble metal working fluids. Electrochemical potential of Cu/Zn ion is -268mV, and easily makes radicals with molecular oxygen. Especially, hydroperoxide radical shows strong toxicity to the strains. Plasma membrane causes conformational change when hydroperoxide radical binds to plasma membrane. Elution of copper ion from copper alloy metal fiber is detected in metal working fluid. As a result antimicrobial activity of copper alloy metal fiber in metal working fluid is superior to that of copper fiber.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.162-167
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• 2000

Synthetic water-based metal-cutting fluids are increasingly popular in the metal-working industry because of its environmental friendliness. However, the fluids have the problem to be decomposed by microbes with use. Thus, it is very important to evaluate the stabilities of the fluids against microbes for the excellent fluids. The purpose of this study is to investigate the biodegradability of several lubricating agents used to improve anti-wear property of the fluids. From the study, it was found that there existed some difference on the biodegradability against microbes such as Escherichia coli and Klepsiella pneumoniae depended on the structure of the lubricating agents and pH of the fluids.

• 한국정밀공학회지
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• 제18권2호
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• pp.161-170
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• 2001

Synthetic water-based metal-cutting fluids are increasingly popular in the metal-working industry because of its environmental friendliness. The propose of this study is to investigate the synergistic effect of combining polyethylene glycol and common fatty acid in formulating a metal-cutting fluid. The tested metals were aluminum, copper and steel, and the test was performed with a modified drilling machine. From the study, it was found that there existed some synergistic effects on the drilling efficiency of the metals to decrease of cutting time, cutting energy, torque as well as the smoothness of surface depended on the formulation ratio of the two fluids.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.206-208
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• 2002

Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the life of the tool , carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface, reduce wear and galling, Protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the result ins level of exposure) depends on many factors. To reduce the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum Quantity in all over the mechanical machining field including high speed type heavy cult ing process.

• Korean Chemical Engineering Research
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• 제44권4호
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• pp.350-355
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• 2006

절삭유제의 미생물에 대한 부패능을 평가하기 위하여 미생물의 성장 유형을 조사하고 조절된 균을 절삭유제에 접종하여 부패능을 실험하였다. 미생물의 성장곡선 실험 결과, 균의 대수성장기는 균의 종류에 따라 다르게 나타났으며 E. coli 균의 대수 성장기는 배양 후 2시간, K. pneumoniae 균은 3시간, P. aeruginosa 균은 4시간, P. oleovarans 균은3시간이었다. OD 값을 0.5로 조절한 접종액의 E. coli 균수는 $4.4{\sim}10.0{\times}10^5CFU/mL$, K. pneumoniae 균수는 $1.8{\sim}9.5{\times}10^7CFU/mL$이었다. 미생물의 부패에 대한 pH의 영향을 살펴본 결과, pH 6~8에서 부패가 왕성하게 진행되었고 pH가 4 이하, 10이상에서는 균이 성장하지 못함을 알 수 있었다. pH를 중성으로 유지하고 내마모제의 구조에 따른 부패능을 실험한 결과, 에스테르형 내마모제가 에틸렌글리콜형 내마모제 보다 부패가 빠르게 진행되어 구조에 따라 부패능의 차이를 나타내었다.

• 한국산업보건학회지
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• 제24권4호
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• pp.416-424
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• 2014

Objectives: The objective of this study is to analyze the predominant microorganisms in the industry treating MWFs(Metal working fluids). Methods: The bacteria and fungi were collected by agar plate impaction and bulk MWFs in storage tank at 54 sites in 9 shops in South Korea. The dominant bacteria and fungi isolated from agar media were identified by fatty acid analysis and morphological analysis, respectively. Results: Totally 111 dominant bacteria were identified in the process, outdoor, and bulk MWFs. The predominant bacterial genus was Micrococcus and Bacillus in the process and outdoor, Pseudomonas in bulk MWF. Among the identified 119 strains of fungi, Cladosporium and Penicillium genus were dominated. The ratios of bacteria designated biosafety level 2 and 1 were 30% and 21%, respectively. Conclusions: This study has investigated the dominant microorganisms in soluble MWF using industry. And it was useful that the qualitative evaluation method along with quantitative analysis for better understanding of the biological factors in the work environment.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 1998년도 추계 학술논문발표회 논문집
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• pp.99-104
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• 1998

산업현장에서 많이 쓰이는 절삭설비(Metal Working : MW)는 매우 다양하여 일일이 열거하기는 어렵고 주로 자동차생산업종, 농기구제조업종, 각종 기계기구 생산업종, 경금속가공업종 등에서 매우 광범위하게 사용되고 있다. 이들 업종에서 연마, 절단, 천공, 드릴링, 터닝(turning)등을 수행하는 많은 근로자들이 다량의 MWF(Metal Working Fluids) 뿐만 아니라 열악한 소음환경에 노출되고 있다. (중략)

• 한국산업보건학회지
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• 제24권3호
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• pp.300-309
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• 2014

Objectives: The objective of this study is to evaluate microbial exposure hazards in the metal-working fluids(MWF) handling industry. Methods: Air quality parameters(airborne bacteria, fungi, endotoxin and oil mist) and bulk MWF in storage tanks were evaluated at 54 points at nine sites in South Korea. Results: The geometric means(GM) of culturable airborne bacteria, fungi, endotoxin and oil mist concentration were $133CFU/m^3$(n=376, range $7{\sim}6,510CFU/m^3$), $159CFU/m^3$(n=381, range $7{\sim}8,469CFU/m^3$), $8.06EU/m^3$(n=103, range $0.34{\sim}280.4EU/m^3$) and $0.20mg/m^3$(n=104, range $0.01{\sim}2.87mg/m^3$), respectively. The ratio of indoor to outdoor concentration was 2.7 for bacteria, 6.1 for endotoxin, and 4.8 for oil mist. Even though average airborne bacteria concentration did not exceed recommended exposure limits($1,000CFU/m^3$), MWF in the storage tanks was highly contaminated with bacteria(arithmetic mean $2.1{\times}10^6CFU/ml$) and exceeded recommended bacteria limits($10^5CFU/ml$). Conclusions: It is necessary for MWF handling workplaces to conduct periodical biohazard inspection of MWF storage tanks. Additionally, further research may be necessary to establish biological occupational exposure limits.