Upgrading of Oil Shale by Flotation Without Collector

Natural Resources Research - Oil shale impurities prevent its direct usage as a source of energy. Removing or reducing of these impurities before retorting can reduce the cost of oil shale...     

Subpollen Particles as Atmospheric Cloud Condensation Nuclei

Izvestiya, Atmospheric and Oceanic Physics - Bioparticles constitute a significant fraction of atmospheric aerosol. Their size range varies from nanometers (macromolecules) to hundreds of...     

Method for Validation of the Onboard Attitude Control System Software of the <Emphasis Type="Italic">Auriga</Emphasis> Earth Remote Sensing Small Spacecraft

The paper considers a digital modeling complex for the attitude control system of the Auriga Earth remote sensing small spacecraft. Mathematical models of measuring and executive devices are described. The results of spacecraft orbital attitude tests are presented.     

Radial velocity and magnetic field measurements of the a-type supergiant ν cep (HD 207260)

On the basis of 55 Zeeman spectrograms obtained at Tautenburg in the years 1975–1979 the effective magnetic fields and the radial velocities of the supergiant ν Cep (HD 207260) were determined. For the effective magnetic field a slow variation occurring on a time scale of years was found. The spectrograms taken at the first time show only moderate effective magnetic field strengths of a few hundred Gauß, but in the year 1978 values of +2000 Gauß were detected. The measured radial velocities show a longtime variability similar to that of the magnetic field as well as more rapid changes. A periodical variation of the radial velocity with a period of ∼ 39.9 days, perhaps produced by the rotation of the star, is indicated. The Balmer absorption lines H_β, H_β, and H_δ have different radial velocities refering to the presence of an expanding envelope. Moreover, there exist significant differences between the velocities of various elements respectively ions of 1–4 km/s.