Periodic Phenomena Observed with Spherical Particles in Horizontal Pipes

A thin layer of spherical particles resting on the bottom of a round pipe was observed to form into essentially equally spaced clumps or islands at fluid velocities only slightly greater than those required to initiate particle movement. This phenomenon appeared to be similar to dune formation in open channels since the ratio of the square of the stream velocity, U, and the product of the gravitational constant, g(L), and the island wavelength, lambda, was correlated by the same function of island height and velocity, particle diameter, and fluid depth regardless of whether the flow was through a closed conduit or an open channel.

THE RATE OF ADSORPTION OF SOME LOW BOILING GASES ON A MODIFIED SARAN CHARCOAL

The pyrolysis at 300 °C. of vinylidene chloride monomer adsorbed on Saran charcoal alters the pore structure of the charcoal so that low boiling gases such as nitrogen are adsorbed slowly. The rates of adsorption of nitrogen, argon, and methane have been measured. They were found to vary with pressure and temperature, and from the temperature variation an activation energy may be calculated. A new method of determining this energy is described which involves changing the temperature during only one adsorption experiment.