Exponentially growing solutions in homogeneous Rayleigh-Benard convection

It is shown that homogeneous Rayleigh-Benard flow, i.e., Rayleigh-Benard turbulence with periodic boundary conditions in all directions and a volume forcing of the temperature field by a mean gradient, has a family of exact, exponentially growing, separable solutions of the full non-linear system of equations. These solutions are clearly manifest in numerical simulations above a computable critical value of the Rayleigh number. In our numerical simulations they are subject to secondary numerical noise and resolution dependent instabilities that limit their growth to produce statistically steady turbulent transport.Comment: 4 pages, 3 figures, to be published in Phys. Rev. E - rapid communication

Construction and Evaluation of the Performance of a Horizontal Well in a Shallow, Thin Aquifer

Since infiltration galleries have been effective as a means of securing large quantities of water from thin aquifers, the question has arisen as to whether or not a small horizontal well that would yield sufficient water for irrigation could be constructed at a cost that would be within the budget of the family-sized farm in South Dakota. If so, a subsequent problem would be the development of some method of estimating the quantity of water a particular aquifer will yield to such a well. A possible approach would be to relate a certain length of horizontal casing to a vertical well of some particular diameter. If such a relationship can be found, the performance of such a well in another place could be predicted from data collected during a conventional pump test. This study will be confined to the details of the dragline construction of a pit, the placement of a horizontal well in a shallow thin aquifer; a, and an actual pump test to learn if a certain length of horizontal casing may be equivalent to a vertical well of some particular radius

Phase space dynamics of overdamped quantum systems

The phase space dynamics of dissipative quantum systems in strongly condensed phase is considered. Based on the exact path integral approach it is shown that the Wigner transform of the reduced density matrix obeys a time evolution equation of Fokker-Planck type valid from high down to very low temperatures. The effect of quantum fluctuations is discussed and the accuracy of these findings is tested against exact data for a harmonic system.Comment: 7 pages, 2 figures, to appear in Euro. Phys. Let

Fuel quality/processing study. Volume 4: On site processing studies

Fuel treated at the turbine and the turbine exhaust gas processed at the turbine site are studied. Fuel treatments protect the turbine from contaminants or impurities either in the upgrading fuel as produced or picked up by the fuel during normal transportation. Exhaust gas treatments provide for the reduction of NOx and SOx to environmentally acceptable levels. The impact of fuel quality upon turbine maintenance and deterioration is considered. On site costs include not only the fuel treatment costs as such, but also incremental costs incurred by the turbine operator if a turbine fuel of low quality is not acceptably upgraded

CHICAGO MEDICAL SOCIETY.: Stated Meeting, Oct. 18, 1886.

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