The Experts below are selected from a list of 5076 Experts worldwide ranked by ideXlab platform
Michael J. Ellenbecker - One of the best experts on this subject based on the ideXlab platform.
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Airborne Nanoparticle Exposures while Using Constant-Flow, Constant-Velocity, and Air-Curtain-Isolated Fume Hoods
Annals of Occupational Hygiene, 2009Co-Authors: Su-jung Tsai, Rong Fung Huang, Michael J. EllenbeckerAbstract:Tsai et al. (Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume Hoods. J Nanopart Res 2009; 11: 147–61) found that the handling of dry nanoalumina and nanosilver inside laboratory fume Hoods can cause a significant release of airborne nanoparticles from the Hood. Hood Design affects the magnitude of release. With traditionally Designed fume Hoods, the airflow moves horizontally toward the Hood cupboard; the turbulent airflow formed in the worker wake region interacts with the vortex in the constant-flow fume Hood and this can cause nanoparticles to be carried out with the circulating airflow. Airborne particle concentrations were measured for three Hood Designs (constant-flow, constant-velocity, and air-curtain Hoods) using manual handling of nanoalumina particles. The Hood operator’s airborne nanoparticle breathing zone exposure was measured over the size range from 5 nm to 20 mm. Experiments showed that the exposure magnitude for a constant-flow Hood had high variability. The results for the constant-velocity Hood varied by operating conditions, but were usually very low. The performance of the air-curtain Hood, a new Design with significantly different airflow pattern from traditional Hoods, was consistent under all operating conditions and release was barely detected. Fog tests showed more intense turbulent airflow in traditional Hoods and that the downward airflow from the double-layered sash to the suction slot of the air-curtain Hood did not cause turbulence seen in other Hoods.
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Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume Hoods
Journal of Nanoparticle Research, 2008Co-Authors: Su-jung Tsai, Jacqueline A. Isaacs, Michael J. EllenbeckerAbstract:Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume Hood. Such Hoods rely on the proper face velocity for optimum performance. In addition, several other Hood Design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume Hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume Hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher’s breathing zone and upstream and downstream from the handling location. Variable factors studied included Hood Design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume Hoods can result in a significant release of airborne nanoparticles from the fume Hood into the laboratory environment and the researcher’s breathing zone. Many variables were found to affect the extent of particle release including Hood Design, Hood operation (sash height, face velocity), work practices, type and quantity of the material being handled, room conditions, and the adequacy of the room exhaust.
Su-jung Tsai - One of the best experts on this subject based on the ideXlab platform.
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Airborne Nanoparticle Exposures while Using Constant-Flow, Constant-Velocity, and Air-Curtain-Isolated Fume Hoods
Annals of Occupational Hygiene, 2009Co-Authors: Su-jung Tsai, Rong Fung Huang, Michael J. EllenbeckerAbstract:Tsai et al. (Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume Hoods. J Nanopart Res 2009; 11: 147–61) found that the handling of dry nanoalumina and nanosilver inside laboratory fume Hoods can cause a significant release of airborne nanoparticles from the Hood. Hood Design affects the magnitude of release. With traditionally Designed fume Hoods, the airflow moves horizontally toward the Hood cupboard; the turbulent airflow formed in the worker wake region interacts with the vortex in the constant-flow fume Hood and this can cause nanoparticles to be carried out with the circulating airflow. Airborne particle concentrations were measured for three Hood Designs (constant-flow, constant-velocity, and air-curtain Hoods) using manual handling of nanoalumina particles. The Hood operator’s airborne nanoparticle breathing zone exposure was measured over the size range from 5 nm to 20 mm. Experiments showed that the exposure magnitude for a constant-flow Hood had high variability. The results for the constant-velocity Hood varied by operating conditions, but were usually very low. The performance of the air-curtain Hood, a new Design with significantly different airflow pattern from traditional Hoods, was consistent under all operating conditions and release was barely detected. Fog tests showed more intense turbulent airflow in traditional Hoods and that the downward airflow from the double-layered sash to the suction slot of the air-curtain Hood did not cause turbulence seen in other Hoods.
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Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume Hoods
Journal of Nanoparticle Research, 2008Co-Authors: Su-jung Tsai, Jacqueline A. Isaacs, Michael J. EllenbeckerAbstract:Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume Hood. Such Hoods rely on the proper face velocity for optimum performance. In addition, several other Hood Design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume Hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume Hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher’s breathing zone and upstream and downstream from the handling location. Variable factors studied included Hood Design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume Hoods can result in a significant release of airborne nanoparticles from the fume Hood into the laboratory environment and the researcher’s breathing zone. Many variables were found to affect the extent of particle release including Hood Design, Hood operation (sash height, face velocity), work practices, type and quantity of the material being handled, room conditions, and the adequacy of the room exhaust.
Michał Pomorski - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical flow analysis and Design optimization of a fume Hood using the CFD method
Chemical Engineering Research & Design, 2018Co-Authors: Sławomir Pietrowicz, Piotr Kolasiński, Michał PomorskiAbstract:Abstract The experimental and numerical analyses of the standard fume Hood features in order to determine the nature of the flow phenomena within the working chamber are presented and studied in the paper. The experiments were carried out for three characteristic heights of the vertical sliding sash, i.e., the lowest (closed), working and the highest (fully opened) heights. The air flow parameters such as: mass flow rate, local distribution of velocity at the exhaust plenum and inlet and pressure drop were measured and analyzed. Assuming isothermal, incompressible and turbulence flow of the air treated as ideal gas, the numerical model based on the continuity and momentum equations was proposed and solved using the Finite Volume Method (FVM). The numerical model was validated against the obtained experimental results. The goal of the numerical simulations was to investigate the flow structure and condition inside the fume Hood for different heights of a vertical sliding sash. The obtained numerical results indicated the intensified air recirculation zones within the fume Hood chamber and showed the complicated nature of the flow. The conclusions and fume Hood Design guidelines aimed at reducing the size of the recirculation zones and thus reducing the noise and power needed to drive the exhaust fan were determined. On the basis of the performed calculations four modifications of the fume Hood Design were proposed and numerically analyzed. Finally, the reduction of the recirculation zones therefore a decrease of pressure drop by 30.5% was achieved.
Sławomir Pietrowicz - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical flow analysis and Design optimization of a fume Hood using the CFD method
Chemical Engineering Research & Design, 2018Co-Authors: Sławomir Pietrowicz, Piotr Kolasiński, Michał PomorskiAbstract:Abstract The experimental and numerical analyses of the standard fume Hood features in order to determine the nature of the flow phenomena within the working chamber are presented and studied in the paper. The experiments were carried out for three characteristic heights of the vertical sliding sash, i.e., the lowest (closed), working and the highest (fully opened) heights. The air flow parameters such as: mass flow rate, local distribution of velocity at the exhaust plenum and inlet and pressure drop were measured and analyzed. Assuming isothermal, incompressible and turbulence flow of the air treated as ideal gas, the numerical model based on the continuity and momentum equations was proposed and solved using the Finite Volume Method (FVM). The numerical model was validated against the obtained experimental results. The goal of the numerical simulations was to investigate the flow structure and condition inside the fume Hood for different heights of a vertical sliding sash. The obtained numerical results indicated the intensified air recirculation zones within the fume Hood chamber and showed the complicated nature of the flow. The conclusions and fume Hood Design guidelines aimed at reducing the size of the recirculation zones and thus reducing the noise and power needed to drive the exhaust fan were determined. On the basis of the performed calculations four modifications of the fume Hood Design were proposed and numerically analyzed. Finally, the reduction of the recirculation zones therefore a decrease of pressure drop by 30.5% was achieved.
Jacqueline A. Isaacs - One of the best experts on this subject based on the ideXlab platform.
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Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume Hoods
Journal of Nanoparticle Research, 2008Co-Authors: Su-jung Tsai, Jacqueline A. Isaacs, Michael J. EllenbeckerAbstract:Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume Hood. Such Hoods rely on the proper face velocity for optimum performance. In addition, several other Hood Design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume Hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume Hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher’s breathing zone and upstream and downstream from the handling location. Variable factors studied included Hood Design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume Hoods can result in a significant release of airborne nanoparticles from the fume Hood into the laboratory environment and the researcher’s breathing zone. Many variables were found to affect the extent of particle release including Hood Design, Hood operation (sash height, face velocity), work practices, type and quantity of the material being handled, room conditions, and the adequacy of the room exhaust.