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- Author or Editor: J. F. Stampfer Jr. x
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Abstract
The evaporation rates of small (radius 3–9 μ), freely failing water droplets were determined. The droplets, produced in a diffusion cloud chamber, were allowed to fall through air of known relative humidity (95–99%) and at three ambient temperatures (25, 30 and 35C) in. a vertical drift tube. The rates of evaporation were ascertained by recording the drop positions on film at fixed time intervals. The results are compared with several existing theories, and are found to lie between the formulation of Kinzer and Gunn and the quasi-stationary theory based on Maxwell's equation.
Abstract
The evaporation rates of small (radius 3–9 μ), freely failing water droplets were determined. The droplets, produced in a diffusion cloud chamber, were allowed to fall through air of known relative humidity (95–99%) and at three ambient temperatures (25, 30 and 35C) in. a vertical drift tube. The rates of evaporation were ascertained by recording the drop positions on film at fixed time intervals. The results are compared with several existing theories, and are found to lie between the formulation of Kinzer and Gunn and the quasi-stationary theory based on Maxwell's equation.
Abstract
Experimental evidence for enhanced evaporation of small (3–9 μ radius) water droplets is presented. Both “pure” droplets and droplets contaminated with surface active materials that were dropped into air of known relative humidity (96–99%) at an ambient temperature of 29.9C evaporated. The rates of evaporation were determined by photographing the evaporating drops, measuring the distance they fell during a fixed time interval, and applying Stokes law. The contaminated droplets exhibited a rate of evaporation approximately 1.8 μ2 sec−1 faster than the “pure” drops. This increase can be compared with rates for “pure” drops of 1.9 and 5.7 μ2 sec−1 at 0.1 and 0.3C dew point depressions, respectively. It is suggested that this phenomenon is caused by the ejection of tiny spurts of water from the drop, this action being a result of the presence of foreign molecules adsorbed on the surface.
Abstract
Experimental evidence for enhanced evaporation of small (3–9 μ radius) water droplets is presented. Both “pure” droplets and droplets contaminated with surface active materials that were dropped into air of known relative humidity (96–99%) at an ambient temperature of 29.9C evaporated. The rates of evaporation were determined by photographing the evaporating drops, measuring the distance they fell during a fixed time interval, and applying Stokes law. The contaminated droplets exhibited a rate of evaporation approximately 1.8 μ2 sec−1 faster than the “pure” drops. This increase can be compared with rates for “pure” drops of 1.9 and 5.7 μ2 sec−1 at 0.1 and 0.3C dew point depressions, respectively. It is suggested that this phenomenon is caused by the ejection of tiny spurts of water from the drop, this action being a result of the presence of foreign molecules adsorbed on the surface.
Abstract
The records from pollutant sensors abroad two aircraft are compared. The aircraft flew along arcs of either 80 or 120 km radius from the Gateway Arch in St. Louis. One aircraft contained a light-scattering instrument which determined the concentrations of particles with radii between 0.15 and 0.30 μm and between 0.30 and 1.3 μm. The other airplane contained an integrating nephelometer, a condensation nucleus counter, and an ozone monitor. It appears that neither the concentration of the condensation nuclei nor the ozone concentration are as reliable indicators of the location of the St. Louis plume at these distances as are data from the light-scattering particle counter or the nephelometer.
Abstract
The records from pollutant sensors abroad two aircraft are compared. The aircraft flew along arcs of either 80 or 120 km radius from the Gateway Arch in St. Louis. One aircraft contained a light-scattering instrument which determined the concentrations of particles with radii between 0.15 and 0.30 μm and between 0.30 and 1.3 μm. The other airplane contained an integrating nephelometer, a condensation nucleus counter, and an ozone monitor. It appears that neither the concentration of the condensation nuclei nor the ozone concentration are as reliable indicators of the location of the St. Louis plume at these distances as are data from the light-scattering particle counter or the nephelometer.
