The Experts below are selected from a list of 2484 Experts worldwide ranked by ideXlab platform
Wenhai Xu - One of the best experts on this subject based on the ideXlab platform.
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permeation of a Metalworking Fluid through a latex glove under field use conditions
Bulletin of Environmental Contamination and Toxicology, 2010Co-Authors: Wenhai XuAbstract:Whole glove testing for a Metalworking Fluid (MWF) in the field was performed for the first time. Green latex gloves used in a machine shop were exposed for 20 min to MWF. The permeated amount (1.0 ± 0.5 μg/cm2) was higher than the threshold (0.25 μg/cm2) for the ASTM F739-99a closed-loop normalized breakthrough time.
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permeation of a straight oil Metalworking Fluid through disposable nitrile chloroprene vinyl and latex gloves
Journal of Hazardous Materials, 2007Co-Authors: Wenhai XuAbstract:Abstract The aim was to investigate the permeation of a straight oil Metalworking Fluid (MWF) through four types of glove materials using the gravimetric method and the modified American Society for Testing and Materials (ASTM) F739-99a method with perfluorohexane and hexane as collection solvents. The residual masses on the collection side were determined after solvent evaporation for both MWF and blank (air) challenges. With perfluorohexane, the permeated MWF through gloves after 8 h was around the lower quantifiable limit for nitrile, 0.7 ± 0.2 mg/cm2 for vinyl, 10.0 ± 1.2 mg/cm2 for chloroprene, and 33.0 ± 0.7 mg/cm2 for latex. Hexane increased the amounts and rates of MWF permeating all gloves 39–73 times, except for vinyl where extractable mass was so high that the residues for MWF challenges and for hexane blanks were indistinguishable. Hexane as a collection solvent also extracted more glove components than did perfluorohexane, and back-permeated gloves in much larger amounts. Perfluorohexane allows better estimates of the real permeation rates and breakthrough times than does hexane. Recommendations based on breakthrough times and permeation rates with hexane collection are thus too conservative, although the relative ranking of these four types of gloves was the same with either collection solvent.
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permeation of a straight oil Metalworking Fluid through a disposable and a chemically protective nitrile glove
Journal of Hazardous Materials, 2006Co-Authors: Wenhai XuAbstract:Abstract The aim of the present study was to quantify the permeation parameters of a complex water-insoluble straight oil Metalworking Fluid (MWF) of low volatility through nitrile gloves. The permeation through a chemically protective and a disposable glove was investigated using the American Society for Testing and Materials (ASTM) F739-99a method with hexane as the collection medium. Analysis of collection side samples involved gas chromatography–mass spectrometry (GC–MS) and gravimetry. The detection breakthrough time for the chemically protective glove was >10 h. For the disposable glove, the detection breakthrough time was 0.7 ± 0.3 h, the lag time was 1.6 ± 0.1 h, the diffusion coefficient was (3.7 ± 0.3) × 10 −9 cm 2 /min, and the steady state permeation rate was 3.5 ± 2.2 μg/cm 2 /min. The disposable nitrile glove can be worn for about 30 min for incidental contact with straight oil MWFs without known carcinogens. The chemically protective nitrile glove should be worn otherwise. The chromatogram for the permeate differed from that of the original MWF, resulting from the faster permeation of lower molecular weight congeners. The combination of chromatography and gravimetry allowed quantifying the permeation parameters of complex water-insoluble non-volatile mixtures.
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gas chromatography mass spectrometry analysis of di n octyl disulfide in a straight oil Metalworking Fluid application of differential permeation and box cox transformation
Journal of Chromatography A, 2006Co-Authors: Wenhai XuAbstract:Abstract The aim of this study was to identify and quantify an unknown peak in the chromatogram of a very complex mixture, a straight oil Metalworking Fluid (MWF). The fraction that permeated through a thin nitrile polymer membrane had less mineral oil background than the original MWF did at the retention time of the unknown peak, thus facilitating identification by total ion current (TIC) gas chromatography–mass spectrometry (GC–MS). The peak proved to be di- n -octyl disulfide (DOD) through retention time and mass spectral comparisons. Quantitation of DOD was by extracted ion chromatogram analysis of the DOD molecular ion (mass-to-charge ratio ( m / z ) 290), and of the m / z 71 ion for the internal standard, n -triacontane. Linear models of the area ratio ( y ) of these two ions versus DOD concentration showed a systematic negative bias at low concentrations, a common occurrence in analysis. The linear model of y 0.8 (from Box–Cox power transformation) versus DOD concentration showed negligible bias from the lowest measured standard of 1.51 mg/L to the highest concentration tested at 75.5 mg/L. The intercept did not differ statistically from zero. The concentration of DOD in the MWF was then calculated to be 0.398 ± 0.034% (w/w) by the internal standard method, and 0.387 ± 0.036% (w/w) by the method of standard additions. These two results were not significantly different at p ≤ 0.05. The Box–Cox transformation is therefore recommended when the data for standards are non-linear.
Nandakishore Rajagopalan - One of the best experts on this subject based on the ideXlab platform.
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partial pore blocking in microfiltration recycling of a semisynthetic Metalworking Fluid
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2008Co-Authors: John E Wentz, Shiv Gopal Kapoor, Richard E Devor, Nandakishore RajagopalanAbstract:In this paper, the fouling of sintered α-alumina membranes by an uncontaminated semisynthetic Metalworking Fluid (MWF) is addressed. Experimental evidence of the form of flux reduction curves, scanning electron microscope images of the membranes, and MWF particle size measurements is used to identify two fouling mechanisms, pore blocking and partial pore blocking, as the major contributors to flux decline. A probability-based mechanistic model is developed based on the time-dependent particle size distribution and membrane pore sizes. The model is fitted to experimental data from two commonly used membrane pore sizes with good agreement. Partial blocking is shown to be a predominant first step in the pore blocking mechanism in microfiltration of semisynthetic MWFs due to the tortuous nature of the pores present in sintered ceramic membranes.
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development of a novel Metalworking Fluid engineered for use with microfiltration recycling
Journal of Tribology-transactions of The Asme, 2006Co-Authors: John E Wentz, Shiv Gopal Kapoor, Richard E Devor, Nandakishore RajagopalanAbstract:Membrane microfiltration is a promising technology that has been shown to extend Metalworking Fluid (MWF) life by eliminating contaminants while allowing the Fluid to stay in use. However, the efficacy of this technology is compromised by the clogging of the filter pores in a process known as membrane fouling. In this paper the fouling issue is addressed by the development of a semi-synthetic MWF specifically designed to reduce fouling of microfiltration membranes. The composition of the designed MWF is discussed and compared with a commercial MWF. Cross-flow microfiltration fouling tests were carried out in low pressure, high velocity conditions on ceramic α-alumina membranes. Several common MWF components are shown not to be factors of membrane fouling on these membranes. The flux of the designed Fluid was found to reach an immediate steady-state at about twice the value of the steady-state flux of the tested commercial Fluid. SEM imaging was used to further evaluate membrane fouling by each Fluid. The machining capabilities of the designed Fluid were examined in terms of cutting forces and machining temperature.Copyright © 2006 by ASME
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Formulation and testing of a microfiltration compatible synthetic Metalworking Fluid
Journal of Membrane Science, 2005Co-Authors: Jessica A. Gilmer, Joseph J. Eppert, Nandakishore RajagopalanAbstract:A synthetic Metalworking Fluid (MWF) was formulated with the specific purpose of achieving both necessary functional properties such as lubricity and corrosion inhibition as well as compatibility with microfiltration. The synthetic formulation was assessed to have comparable lubricity and corrosion inhibition relative to a commercial formulation. The microfiltration performance with the newly formulated synthetic was superior to a previously reported study utilizing a commercial formulation. This suggests that successful formulation is possible that preserves both functionality and ease of recycling. However, microfiltration performance was found to be extremely sensitive to trace contaminants in the phosphate ester used in the formulation. Therefore, care needs to be taken to develop appropriate specifications for chemicals used for formulating membrane compatible Metalworking Fluids.
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the influence of Fluid management policy and operational changes on Metalworking Fluid functionality
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2004Co-Authors: M H Greeley, Richard E Devor, Shiv Gopal Kapoor, Nandakishore RajagopalanAbstract:This paper discusses the influence of Metalworking Fluid management policy and operational changes on Metalworking Fluid functionality in terms of lubricating and cooling ability. Several important pathways for Metalworking Fluid depletion are reviewed. Using an instrumented drilling-based test-bed, the effects of lubricating component depletion, microfiltration, and dilutant water hardness were assessed. It was observed that microfiltration had no effect on Fluid functionality. Increases in dilutant water hardness were found to produce decreases in drilling forces and temperature. Additionally, increasing dilutant hardness decreased microfiltration flux, but this effect can be counteracted with the addition of a chelating agent.
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impact of environmental contaminants on machining properties of Metalworking Fluids
Tribology International, 2004Co-Authors: M H Greeley, Nandakishore RajagopalanAbstract:Increased attention to Metalworking Fluid (MWF) management has neglected to assess the effect of continued use on the functionality of contaminated Fluids. To address this, experiments have been conducted to evaluate the lubricating, cooling, corrosion inhibition, and surface roughness functionalities of Metalworking Fluids subjected to both extended industrial use and contamination in a laboratory setting. The results of these experiments show no reduction in any evaluated functionality for used Metalworking Fluids. Metalworking Fluids artificially contaminated with calcium, chloride, or hydraulic oil only exhibited reduced lubricating and cooling functionality when calcium levels were so high as to cause emulsion destabilization.
Susan M Kennedy - One of the best experts on this subject based on the ideXlab platform.
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determinants of exposure to Metalworking Fluid aerosol in small machine shops
Annals of Occupational Hygiene, 2004Co-Authors: Andrew Ross, Kay Teschke, Michael Brauer, Susan M KennedyAbstract:The purpose of this study was to evaluate personal exposure to Metalworking Fluid (MWF) aerosols in very small machine shops (1–8 machinists per shop) and to investigate workplace factors associated with exposures. A total of 20 willing machine shops in Vancouver, Canada (from 46 eligible shops, 43%) and 88 machinists participated (participation rate for machinists 92%). Most machinists wore two personal sampling trains (an open-faced 37 mm cassette and a PM 10 impactor) on each of two full work shifts. Observational data were collected regarding potential determinants of exposure at 15 min intervals throughout each shift. A total of 322 personal samples were taken over 54 days. Mean aerosol exposure was 0.32 mg/m3 (range 0.06–2.19) for the 37 mm cassette samples and 0.27 mg/m3 (range 0.026–3.67) for PM 10 . Exposures from the two sampler types were highly correlated (R = 0.86). The mean shop-specific ratio comparing exposure from the 37 mm cassette with that from the PM 10 sampler was 1.43 and varied significantly across shops, ranging from 0.97 to 2.19. Machine, task and shop characteristics associated with significantly increased aerosol exposure included the proportion of time spent grinding, operating an enclosed computer controlled machine, the presence of welding in the shop for both sampler types and the number of machines using MWF for PM 10 samples only. Factors associated with reduced aerosol exposure included machining aluminum, milling, the height (and shape) of the shop roof (for both sample types) and the presence of mechanical shop ventilation (for the 37 mm cassette samples).
Linnea Lillienberg - One of the best experts on this subject based on the ideXlab platform.
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respiratory symptoms and exposure response relations in workers exposed to Metalworking Fluid aerosols
Annals of Occupational Hygiene, 2010Co-Authors: Linnea Lillienberg, Eva Andersson, Bengt Jarvholm, Kjell TorenAbstract:The aim of the study was to identify specific health risks and exposure–response relationships associated with exposure to Metalworking Fluid (MWF) aerosols. In a cross-sectional study of machine workers exposed to MWF aerosols in five companies in Sweden, a self-administered questionnaire about health symptoms, work tasks, and exposure situations was sent out to 2294 employees, 1632 exposed and 662 referents. Referents were office workers and metal workers not working with MWFs. In four of the companies, there were recent measurements of personal exposure to MWF aerosols. Log-binomial regression models were used to estimate prevalence ratios with 95% confidence intervals for different health outcomes in relation to different variables of exposure. The response rate after two reminders was 67% resulting in 1048 (923 male, 125 female) workers exposed to MWF aerosols and 451 (374 male, 77 female) referents. The study indicates that metal workers in Sweden currently exposed to a mean value of MWF aerosols of 0.4 mg m 23 have a significantly higher prevalence of wheeze, chronic bronchitis, chronic rhinitis, and eye irritation compared to the referents. At a mean exposure of 0.4 mg m 23 , a level below the Swedish 8-h exposure limit value of 1 mg m 23 , machine operators showed increased prevalence of symptoms in eyes and airways. Thus, the current exposure limit value does not seem to protect the workers from such symptoms.
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exposure to Metalworking Fluid aerosols and determinants of exposure
Annals of Occupational Hygiene, 2008Co-Authors: Linnea Lillienberg, Lennart Mathiasson, Alex Burdorf, Lars ThornebyAbstract:Metalworking Fluid (MWF) aerosols are associated with respiratory disorders including asthma and hypersensitivity pneumonitis. The aims of this study were to describe exposure to inhalable MWF aerosols and volatile compounds in machine shops, to estimate the influence of important determinants of exposure and to compare different sampling techniques for MWF aerosols. Personal full-shift air samples of inhalable aerosol (PAS-6 sampler) and total aerosol (open-faced sampler) were collected on operators in five medium to big-sized machine shops in three companies. The filters were analysed gravimetrically and extracted by supercritical Fluid extraction for MWF aerosol and triethanolamine content. In addition, personal measurements were taken for formaldehyde and volatile compounds on adsorbent samplers. Continuous dust measurements were performed with a real-time instrument (DataRAM) during 2 h periods, using 1-min average values. In total, 95 measurements of inhalable aerosol and extracted MWF aerosols on 51 operators were conducted. Within the companies, the average exposure to inhalable aerosol ranged from 0.19 to 0.25 mg m(-3) with geometric standard deviations from 1.56 to 1.79. On average, the extracted fraction of MWF aerosol was 67% of the inhalable aerosol concentration. The exposure levels of triethanolamine, formaldehyde and volatile compounds were generally low. About 45% of the between-worker variance could be explained by use of compressed air, lack of complete enclosure of machines or grinding as cutting task. In 21 workers with continuous aerosol measurements, short-term peak exposures during 6% of the work time contributed to similar to 25% of the average concentration of inhalable MWF aerosol. Inhalable MWF aerosol concentration measured with the PAS-6 sampler was a factor 2 higher than the concentrations derived from the open-faced sampler. These findings suggest that control measures, such as full enclosure of machines and the elimination of the use of compressed air as cleaning technique, are required to reduce the exposure to MWF aerosols to levels below the expected threshold for adverse respiratory health effects.
Kjell Toren - One of the best experts on this subject based on the ideXlab platform.
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respiratory symptoms and exposure response relations in workers exposed to Metalworking Fluid aerosols
Annals of Occupational Hygiene, 2010Co-Authors: Linnea Lillienberg, Eva Andersson, Bengt Jarvholm, Kjell TorenAbstract:The aim of the study was to identify specific health risks and exposure–response relationships associated with exposure to Metalworking Fluid (MWF) aerosols. In a cross-sectional study of machine workers exposed to MWF aerosols in five companies in Sweden, a self-administered questionnaire about health symptoms, work tasks, and exposure situations was sent out to 2294 employees, 1632 exposed and 662 referents. Referents were office workers and metal workers not working with MWFs. In four of the companies, there were recent measurements of personal exposure to MWF aerosols. Log-binomial regression models were used to estimate prevalence ratios with 95% confidence intervals for different health outcomes in relation to different variables of exposure. The response rate after two reminders was 67% resulting in 1048 (923 male, 125 female) workers exposed to MWF aerosols and 451 (374 male, 77 female) referents. The study indicates that metal workers in Sweden currently exposed to a mean value of MWF aerosols of 0.4 mg m 23 have a significantly higher prevalence of wheeze, chronic bronchitis, chronic rhinitis, and eye irritation compared to the referents. At a mean exposure of 0.4 mg m 23 , a level below the Swedish 8-h exposure limit value of 1 mg m 23 , machine operators showed increased prevalence of symptoms in eyes and airways. Thus, the current exposure limit value does not seem to protect the workers from such symptoms.