The Experts below are selected from a list of 1281 Experts worldwide ranked by ideXlab platform
Peter T. Lapuma - One of the best experts on this subject based on the ideXlab platform.
-
Dissociation of Hexavalent Chromium from Primer Paint Particles into Simulated Mucus Fluid
2005Co-Authors: Michael P Moran, Peter T. LapumaAbstract:Abstract : The military relies heavily on chromate Primer Paints to protect equipment from corrosion. Epidemiological studies link chromate exposure to cancer however limited studies suggest exposure to chromate Paint particles does not increase the risk of lung cancer. The particle size and Paint type may hinder chromate released into lung fluid. To simulate particle deposition in the mucosal layer of the lungs, a viable cascade impactor collected Paint particles into porcine-based simulated lung fluid (SLF). Samples were tested after 24 hours for dissolved and total chromate to determine the fraction of Cr(exp +6)(exp +6) that dissociated from the particles into the Porcine-SLF. In strontium chromate Paints, 0.65-2.1 microns sized particles released significantly less chromate than 2.1-7.0 micron sizes. Barium chromate Paints only released 3-7% of its chromate, while strontium based Paints released from 20-90%. This method demonstrates a technique to evaluate the bioavailability of contaminants from any type of aerosols.
-
Chromate concentration bias in Primer Paint particles.
Regulatory Toxicology and Pharmacology, 2001Co-Authors: Peter T. Lapuma, Joseph M. Fox, Edgar C. KimmelAbstract:Chromate-containing Primer Paints are used to prevent corrosion on metal surfaces. Chromate contains hexavalent chromium (Cr6+), a human carcinogen. The objective of this research was to determine if there is a bias in the fraction of chromate found in various particle sizes generated during Primer Painting operations. A solvent-based, aviation Primer Paint was sprayed using a high-volume, low-pressure spray gun. Paint particles were collected and separated by size with seven-stage cascade impactors. It was determined that particles with a mass aerodynamic diameter 2.0 microm (P 2.0 microm is 70 microg of Cr/mg of dry Paint. The mixed Paint contains 18.75% strontium chromate, which equates to a ratio of 67 microg of Cr/mg of dry Paint. Particles > 2.0 microm are more likely to impact in the upper tracheobronchial regions of the lung where mucociliary clearance is relatively rapid. Additionally, chromate emissions from spraying operations may be overestimated because larger particles, which are more easily trapped on an air filter, contain more chromate than the smaller particles, which are more likely to bypass an air filter.
Edgar C. Kimmel - One of the best experts on this subject based on the ideXlab platform.
-
Chromate concentration bias in Primer Paint particles.
Regulatory Toxicology and Pharmacology, 2001Co-Authors: Peter T. Lapuma, Joseph M. Fox, Edgar C. KimmelAbstract:Chromate-containing Primer Paints are used to prevent corrosion on metal surfaces. Chromate contains hexavalent chromium (Cr6+), a human carcinogen. The objective of this research was to determine if there is a bias in the fraction of chromate found in various particle sizes generated during Primer Painting operations. A solvent-based, aviation Primer Paint was sprayed using a high-volume, low-pressure spray gun. Paint particles were collected and separated by size with seven-stage cascade impactors. It was determined that particles with a mass aerodynamic diameter 2.0 microm (P 2.0 microm is 70 microg of Cr/mg of dry Paint. The mixed Paint contains 18.75% strontium chromate, which equates to a ratio of 67 microg of Cr/mg of dry Paint. Particles > 2.0 microm are more likely to impact in the upper tracheobronchial regions of the lung where mucociliary clearance is relatively rapid. Additionally, chromate emissions from spraying operations may be overestimated because larger particles, which are more easily trapped on an air filter, contain more chromate than the smaller particles, which are more likely to bypass an air filter.
Vladimir Pankov - One of the best experts on this subject based on the ideXlab platform.
-
alternate environmentally friendly de Painting process for aircraft structures atmospheric plasma
Journal of Minerals and Materials Characterization and Engineering, 2017Co-Authors: Ali Akbar Merati, Marko Yanishevsky, Tessa Despinic, Vladimir PankovAbstract:During the lifetime of aircraft structures, Paint removal and re-application cycles are conducted to restore appearance and to enable inspection for fatigue cracks and corrosion damages. Current Paint removals processes, including chemical and abrasive media blasting, yield large amounts of volatile organic compounds and hazardous air pollutants, and generate large quantities of waste which require proper disposal/treatment. They also have the potential to mask surface cracks and decrease the effectiveness of Liquid Penetrant Inspections (LPI). This study compares current Paint stripping methods to a novel Atmospheric Plasma (AP) system, which claims to be a more environmentally friendly method. Aluminium and steel coupons were prepared with military aircraft quality topcoat and Primer Paint schemes and subjected to the three aforemen-tioned Paint stripping processes. The results were then characterized in terms of Paint removal effectiveness, potential damages to the metallic substrates, and effect on the LPI process. Hardness and conductivity measurements as well as metallographic sectioning and microscopy, were used to characterize the stripped samples. The results indicated that AP had no negative ramifications on detecting fatigue cracks in the substrates, and did not alter the temper, mechanical properties of the aerospace alloys studied. The AP process has the potential to replace current hazardous and less environmentally friendly Paint removal methods; though a full systematic qualification and evaluation process is still required for it to be considered as an accepted industrial Paint removal process.
Pankov Vladimir - One of the best experts on this subject based on the ideXlab platform.
-
Alternate environmentally friendly de-Painting process for aircraft structures-atmospheric plasma
Scientific Research Publishing, 2017Co-Authors: Merati Ali, Yanishevsky Marko, Despinic Tessa, Lo Philip, Pankov VladimirAbstract:During the lifetime of aircraft structures, Paint removal and re-application cycles are conducted to restore appearance and to enable inspection for fatigue cracks and corrosion damages. Current Paint removals processes, including chemical and abrasive media blasting, yield large amounts of volatile organic compounds and hazardous air pollutants, and generate large quantities of waste which require proper disposal/treatment. They also have the potential to mask surface cracks and decrease the effectiveness of Liquid Penetrant Inspections (LPI). This study compares current Paint stripping methods to a novel Atmospheric Plasma (AP) system, which claims to be a more environmentally friendly method. Aluminium and steel coupons were prepared with military aircraft quality topcoat and Primer Paint schemes and subjected to the three aforemen-tioned Paint stripping processes. The results were then characterized in terms of Paint removal effectiveness, potential damages to the metallic substrates, and effect on the LPI process. Hardness and conductivity measurements as well as metallographic sectioning and microscopy, were used to characterize the stripped samples. The results indicated that AP had no negative ramifications on detecting fatigue cracks in the substrates, and did not alter the temper, mechanical properties of the aerospace alloys studied. The AP process has the potential to replace current hazardous and less environmentally friendly Paint removal methods; though a full systematic qualification and evaluation process is still required for it to be considered as an accepted industrial Paint removal process.Peer reviewed: YesNRC publication: Ye
Joseph M. Fox - One of the best experts on this subject based on the ideXlab platform.
-
Chromate concentration bias in Primer Paint particles.
Regulatory Toxicology and Pharmacology, 2001Co-Authors: Peter T. Lapuma, Joseph M. Fox, Edgar C. KimmelAbstract:Chromate-containing Primer Paints are used to prevent corrosion on metal surfaces. Chromate contains hexavalent chromium (Cr6+), a human carcinogen. The objective of this research was to determine if there is a bias in the fraction of chromate found in various particle sizes generated during Primer Painting operations. A solvent-based, aviation Primer Paint was sprayed using a high-volume, low-pressure spray gun. Paint particles were collected and separated by size with seven-stage cascade impactors. It was determined that particles with a mass aerodynamic diameter 2.0 microm (P 2.0 microm is 70 microg of Cr/mg of dry Paint. The mixed Paint contains 18.75% strontium chromate, which equates to a ratio of 67 microg of Cr/mg of dry Paint. Particles > 2.0 microm are more likely to impact in the upper tracheobronchial regions of the lung where mucociliary clearance is relatively rapid. Additionally, chromate emissions from spraying operations may be overestimated because larger particles, which are more easily trapped on an air filter, contain more chromate than the smaller particles, which are more likely to bypass an air filter.