The Experts below are selected from a list of 61389 Experts worldwide ranked by ideXlab platform
D. Helfritch - One of the best experts on this subject based on the ideXlab platform.
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The unique abilities of cold Spray deposition
International Materials Reviews, 2016Co-Authors: V. Champagne, D. HelfritchAbstract:Cold Spray material deposition differs signifiCantly from other thermal Spray systems in that the cold Spray process does not melt particles, particle velocities are very high, and the gas/particle jet plume has a relatively low temperature. Cold Spray Can thus be applied to applications with heat-sensitive substrates or those applications that do not allow heat-modified deposits. The impact consolidation of high velocity, solid state, particles yield cold Spray depositions with high strength, low porosity and minimal or compressive residual stress. This review will be useful to individuals new to cold Spray, as well as to the cold Spraying community and to product developers needing cold Spray capability. The applications presented here Can demonstrate capabilities that are of use to new and related uses. The descriptions of the equipment and techniques used to create the cold-Sprayed deposits will be helpful to those individuals and firms seeking to produce products requiring similar characteristics.
V. Champagne - One of the best experts on this subject based on the ideXlab platform.
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The unique abilities of cold Spray deposition
International Materials Reviews, 2016Co-Authors: V. Champagne, D. HelfritchAbstract:Cold Spray material deposition differs signifiCantly from other thermal Spray systems in that the cold Spray process does not melt particles, particle velocities are very high, and the gas/particle jet plume has a relatively low temperature. Cold Spray Can thus be applied to applications with heat-sensitive substrates or those applications that do not allow heat-modified deposits. The impact consolidation of high velocity, solid state, particles yield cold Spray depositions with high strength, low porosity and minimal or compressive residual stress. This review will be useful to individuals new to cold Spray, as well as to the cold Spraying community and to product developers needing cold Spray capability. The applications presented here Can demonstrate capabilities that are of use to new and related uses. The descriptions of the equipment and techniques used to create the cold-Sprayed deposits will be helpful to those individuals and firms seeking to produce products requiring similar characteristics.
U Bangarusamy - One of the best experts on this subject based on the ideXlab platform.
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nitrophenolates Spray Can alter boll abscission rate in cotton through enhanced peroxidase activity and increased ascorbate and phenolics levels
Journal of Plant Physiology, 2010Co-Authors: M Djanaguiraman, Annie J Sheeba, Durga D Devi, U Bangarusamy, P V V PrasadAbstract:Field studies were conducted from 2002 to 2005 to evaluate foliar Spray of Atonik (a plant growth regulator (PGR) containing nitrophenolates) on cotton boll abscission rate by assessing various reactive oxygen species (ROS) contents, antioxidant content and antioxidant enzyme activity from 1 to 9 days after anthesis (DAA). The result indicated that the nitrophenolate Spray reduced hydrogen peroxide (H(2)O(2)), superoxide anion (O(2)(-)) accumulation, lipid peroxidation (malondialdehyde--MDA), lipoxygenase (LOX) activity and membrane permeability relative to the control. Antioxidant enzyme activity (superoxide dismutase, SOD; ascorbate peroxidase, APX; peroxidase, POX; glutathione peroxidase, GSH-Px) was signifiCantly increased by the nitrophenolate Spray. The POX (217%) and GSH-Px (242%) activities were enhanced compared with APX (7.7%) activity at 9 DAA. Enhanced accumulation of ascorbate (245%), phenol (253%) and proline (150%) was observed in nitrophenolate-Sprayed plants compared with control at 9 DAA. Because ascorbate content is increased by higher dehydroascorbate reductase (DHAR) enzyme activity, the ascorbate was able to replenish reducing equivalents to phenoxyl radicals, resulting in an increase of phenolic compounds. The increased phenolic acid content may be involved in scavenging the ROS produced in developing cotton boll. The role of DHAR and glutathione reductase (GR) in keeping higher levels of reduced ascorbate and low levels of endogenous H(2)O(2) in the developing cotton boll may be the prerequisite for boll retention. Based on the present work, we conclude that nitrophenolate-Sprayed plants counteracted the deleterious effects of ROS by the peroxide/phenolics/ascorbate system, which causes reduced boll abscission and increased yield.
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cotton leaf senescence Can be delayed by nitrophenolate Spray through enhanced antioxidant defence system
Journal of Agronomy and Crop Science, 2009Co-Authors: M Djanaguiraman, Annie J Sheeba, Durga D Devi, U BangarusamyAbstract:Leaf senescence is an oxidative process, and most of the catabolic processes involved in senescence are propagated irreversibly once initiated. An experiment was conducted to test the hypothesis that nitrophenolates (Atonik, a plant growth regulator) Spray Can delay the leaf senescence through reduced oxidative damage. Atonik 3.75 g a.i. ha ―1 was Sprayed during boll filling stage on cotton, and the senescence process was evaluated by quantifying total chlorophyll contents, photosynthetic rate, Fv/Fm ratio, various reactive oxygen species (ROS) content, antioxidant content and antioxidant enzyme activity from 90 days after sowing (DAS) to 130 DAS. The result indicated that nitrophenolate Spray reduced the hydrogen peroxide (H 2 O 2 ), superoxide anion (O 2 ― ) accumulation, lipid peroxidation (malondialdehyde), lipoxygenase activity and membrane permeability over unSprayed control. The antioxidant enzyme activity (superoxide dismutase, SOD; ascorbate peroxidase, APX; peroxidase, POX; glutathione peroxidase, GSH-Px) were signifiCantly increased by the nitrophenolate Spray. POX (118.1 %) and GSH-Px (143.3 %) activities were enhanced to a higher level compared to APX (8.5 %) activity at 130 DAS. Enhanced accumulation of ascorbate (144.9 %), phenol (154.7 %) and proline (50 %) was seen in nitrophenolate-Sprayed plants compared with unSprayed control plants at 130 DAS. Ascorbate content is increased by higher dehydro-ascorbate reductase enzyme activity. Ascorbate was thus able to replenish reducing equivalents to phenoxyl radicals resulting in an increase in phenolic compounds. The increased phenolic acid content may be involved in scavenging the ROS produced during senescence process. The higher level of reduced ascorbate and low level of endogenous H 2 O 2 in the leaves may be the prerequisite for delayed leaf senescence in the nitrophenolate-Sprayed plants. Based on the present work, it Can be concluded that nitrophenolate-Sprayed plants Can postpone the leaf senescence by peroxide/phenolic/ascorbate system which is involved in scavenging the ROS produced during leaf senescence.
Agrawal, Ajay K - One of the best experts on this subject based on the ideXlab platform.
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Spray Flame Characteristics of Bio-Derived Fuels in a Simulated Gas Turbine Burner
'ASME International', 2019Co-Authors: Panchasara Heena, Kolhe Pankaj, Agrawal, Ajay KAbstract:Fuel injection plays an important role in liquid fueled gas turbine combustion. The strong interdependence of liquid breakup and atomization, turbulent dispersion of these droplets, droplet evaporation, and fuel-air mixing make the Spray modeling an extremely challenging task. The physical processes are even more difficult to predict for alternative fuels with different thermophysical properties. In this study, Spray flames of unheated and preheated vegetable oil (VO) produced by an air-blast atomizer in a swirl stabilized combustor are investigated experimentally. Phase Doppler particle analyzer (PDPA) is used to measure the instantaneous diameter and axial velocity of droplets at different axial and radial locations in both flames. Experiments are conducted at an equivalence ratio of 0.79 and atomizing air to liquid ratio (ALR) by mass of 2.5 to obtain stable VO flames. Radial profiles of mean axial velocity and Sauter mean diameter are presented to show the effect of fuel preheating. Joint Probability Density Functions (joint PDF) are presented to show the correlation between droplet diameter and axial velocity. Results are analyzed to show that both Sprays exhibit self-similar droplet diameter distributions at different axial and radial locations when normalized properly. Thus, the vast amount of PDPA data in the Spray Can be reduced to simple distribution functions. A method to reconstruct the joint PDF from experimentally determined distribution functions is presented. We envision that the joint PDF approach outlined in this study could be implemented in high-fidelity computational fluid dynamic models to improve Spray predictions in future studies
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Spray flame characteristics of bio-derived fuels in a simulated gas turbine burner
'ASME International', 2019Co-Authors: Panchasara Heena, Kolhe, Pankaj S, Agrawal, Ajay KAbstract:Copyright © 2019 ASME. Fuel injection plays an important role in liquid fueled gas turbine combustion. The strong interdependence of liquid breakup and atomization, turbulent dispersion of these droplets, droplet evaporation, and fuel-air mixing make the Spray modeling an extremely challenging task. The physical processes are even more difficult to predict for alternative fuels with different thermophysical properties. In this study, Spray flames of unheated and preheated vegetable oil (VO) produced by an air-blast atomizer in a swirl stabilized combustor are investigated experimentally. Phase Doppler particle analyzer (PDPA) is used to measure the instantaneous diameter and axial velocity of droplets at different axial and radial locations in both flames. Experiments are conducted at an equivalence ratio of 0.79 and atomizing air to liquid ratio (ALR) by mass of 2.5 to obtain stable VO flames. Radial profiles of mean axial velocity and Sauter mean diameter are presented to show the effect of fuel preheating. Joint Probability Density Functions (joint PDF) are presented to show the correlation between droplet diameter and axial velocity. Results are analyzed to show that both Sprays exhibit self-similar droplet diameter distributions at different axial and radial locations when normalized properly. Thus, the vast amount of PDPA data in the Spray Can be reduced to simple distribution functions. A method to reconstruct the joint PDF from experimentally determined distribution functions is presented. We envision that the joint PDF approach outlined in this study could be implemented in high-fidelity computational fluid dynamic models to improve Spray predictions in future studies
Treye A Thomas - One of the best experts on this subject based on the ideXlab platform.
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nanoparticles containing Spray Can aerosol characterization exposure assessment and generator design
Inhalation Toxicology, 2010Co-Authors: Bean T Chen, Aliakbar Afshari, Samuel Stone, Mark Jackson, Diane Schweglerberry, David G Frazer, Vincent Castranova, Treye A ThomasAbstract:This is the first report demonstrating that a commercially available household consumer product produces nanoparticles in a respirable range. This report describes a method developed to characterize nanoparticles that were produced under typical exposure conditions when using a consumer Spray product. A well-controlled indoor environment was simulated for conducting Spray applications approximating a human exposure scenario. Results indicated that, while aerosol droplets were large with a count median diameter of 22 µm during Spraying, the final aerosol contained primarily solid TiO2 particles with a diameter of 75 nm. This size reduction was due to the surface deposition of the droplets and the rapid evaporation of the aerosol propellant. In the breathing zone, the aerosol, containing primarily individual particles (>90%), had a mass concentration of 3.4 mg/m3, or 1.6 × 105 particles/cm3, with a nanoparticle fraction limited to 170 µg/m3, or 1.2 × 105 particles/cm3. The results were used to estimate the ...
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nanoparticles containing Spray Can aerosol characterization exposure assessment and generator design
Inhalation Toxicology, 2010Co-Authors: Bean T Chen, Aliakbar Afshari, Samuel Stone, Mark Jackson, Diane Schweglerberry, David G Frazer, Vincent Castranova, Treye A ThomasAbstract:This is the first report demonstrating that a commercially available household consumer product produces nanoparticles in a respirable range. This report describes a method developed to characterize nanoparticles that were produced under typical exposure conditions when using a consumer Spray product. A well-controlled indoor environment was simulated for conducting Spray applications approximating a human exposure scenario. Results indicated that, while aerosol droplets were large with a count median diameter of 22 µm during Spraying, the final aerosol contained primarily solid TiO(2) particles with a diameter of 75 nm. This size reduction was due to the surface deposition of the droplets and the rapid evaporation of the aerosol propellant. In the breathing zone, the aerosol, containing primarily individual particles (>90%), had a mass concentration of 3.4 mg/m(3), or 1.6 × 10(5) particles/cm(3), with a nanoparticle fraction limited to 170 µg/m(3), or 1.2 × 10(5) particles/cm(3). The results were used to estimate the pulmonary dose in an average human (0.075 µg TiO(2) per m(2) alveolar epithelium per minute) and rat (0.03 µg TiO(2)) and, consequently, this information was used to design an inhalation exposure system. The system consisted of a computer-controlled solenoid ''finger'' for generating constant concentrations of Spray Can aerosols inside a chamber. Test results demonstrated great similarity between the solenoid ''finger''-dispersed aerosol compared to human-generated aerosol. Future investigations will include an inhalation study to obtain information on dose-response relationships in rats and to use it to establish a No Effect Exposure Level for setting guidelines for this consumer product.