Speed median

The median speed Cm is that speed which is exceeded by half of the molecules. It can be obtained from the integral equation... 

Process parameters of primary importance include roll speed, differential roll speed, roll gap, metal flow rate, metal stream velocity, and melt superheat. The mass median diameter of particles diminishes exponentially as the roll speed increases. It is possible to obtain a smaller mass median diameter when one of the rolls is kept stationary rather than rotating the two rolls at the same speed. Metal flow rate seems to have a negligible effect on the mass median diameter. However, the mass median diameter increases with increasing metal stream velocity, suggesting that the relative velocity of the metal stream to the periphery of the rolls may be a fundamental variable controlling the mass median diameter. The size distribution is approximately constant for the conditions studied. 

The Laser-spin-atomized droplets are usually spherical, clean, and homogeneous in composition. A mass median diameter of 100 pm has been obtained for a Ni-Al-Mo alloy. Cooling rates are estimated to be in the order of magnitude of 105 °C/s. Similarly to other centrifugal atomization techniques, droplet properties (shape, size, cooling rate, etc.) are dependent on the rotation speed, ingot diameter, superheat, and material properties. 

Analytical and empirical correlations for droplet sizes generated by ultrasonic atomization are listed in Table 4.14 for an overview. In these correlations, Dm is the median droplet diameter, X is the wavelength of capillary waves, co0 is the operating frequency, a is the amplitude, UL0 is the liquid velocity at the nozzle exit in USWA, /Jmax is the maximum sound pressure, and Us is the speed of sound in gas. Most of the analytical correlations are derived on the basis of the capillary wave theory. Experimental observations revealed that the mean droplet size generated from thin liquid films on... 

To determine the influence of wind, velocity, and particle size on the toxicity of oil aerosols containing DDT, Latta and coworkers (31) conducted experiments in a wind tunnel at wind speeds of 2, 4, 8, and 16 miles per hour. The median lethal dose for a female mosquito was 1 particle 83 microns in diameter from a 10% DDT solution. 

The mechanism of deposition in the size range 0.1-1 /tm, and the appropriate vg values, have been the subject of some dispute. Sulphate particles in the urban and suburban atmosphere have median diameters of about 0.5 /um (Heard Wiffin, 1969 Whitby, 1978). Using the results of Fig. 6.9, and weighting vg according to the mass of sulphate in various size ranges, Garland (1978) calculated a mean value of vg for sulphate aerosol of 1.0 mm s-1. Nicholson Davies (1987) measured the profile of SO4- concentrations, and also wind speed, above agricul-... 

NIR has been used to determine the mass median diameter of a micronized active compound contained in a lactose monohydrate at a concentration of 4% by weight and a size between 8 and 20 pm [223]. Multivariate statistical analysis was applied to zero order NIR spectra using particle size distributions by low angle laser light scattering as a reference technique. Due to its speed, simplicity and low operating costs it was demonstrated that this is a viable alternative to other methods used to carry out this type of analysis. 

Human volunteers were tested in a wind tunnel at an air speed of five miles per hour (mph) to establish the length of time a subject could remain in the CN-containing air stream. The tolerance time varied with the subject. CN aerosols were generated from acetone solutions at a Ct of 350 mg min m with a mass median diameter of about 0.6 pm. The... 

As the stirer speed increases, not only the average droplet size is reduced, but also the droplet size distribution is markedly narrowed [125, 166]. This situation is graphically shown in Fig. 6.1. A bunching of the curves is realized, if, as in Fig. 6.2, the abscissas and the ordinates are standardized with the corresponding median value dsfl. 

Fig, 6.2 With the median value dso standardized volume density distribution q3(dp/d5o) as a function of dp/dso for the 6-blade turbine impeller at different stirrer speeds and four different chlorohydrocarbons in water ( > = 0.2) from [166]... 

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