Exhaust cloud rise and diffusion in the atmosphere

Analytical approach develops physical-mathematical model of rocket engine exhaust cloud rise, growth, and diffusion. Analytic derivations and resultant model apply to hot exhaust cloud study or industrial stack plumes, making work results applicable to air pollution. Model formulations apply to all exhaust cloud types and various atmospheric conditions

Experimental dynamic stiffness and damping of externally pressurized gas-lubricated journal bearings

A rigid vertical shaft was operated with known amounts of unbalance at speeds to 30,000 rpm and gas supply pressure ratios to 4.8. From measured amplitude and phase angle data, dynamic stiffness and damping coefficients of the bearings were determined. The measured stiffness was proportional to the supply pressure, while damping was little affected by supply pressure. Damping dropped rapidly as the fractional frequency whirl threshold was approached. A small-eccentricity analysis overpredicted the stiffness by 20 to 70 percent. Predicted damping was lower than measured at low speeds but higher at high speeds

UPDATING CORN PROGRAM PAYMENT YIELDS: ARE FARM OPERATORS DIFFERENTIALLY AFFECTED?

Crop yields which determine farm income deficiency payments have been frozen at 1981-1985 levels since 1986. Data from a longitudinal survey of Ohio farm operators are analyzed to evaluate whether updating payment yields will differentially affect farm operators. Results of the analysis imply that farm operators who operate larger farms, live in counties with higher yields, and have higher fertilizer and pesticide expenses per acre of corn will benefit more. In addition, low (high) existing payment yields are understated (overstated) relative to updated payment yields.Agricultural Finance,

Rise and growth of space vehicle engine exhaust and associated diffusion models

Space vehicle plume rise and associated diffusion models at Cape Kennedy Launch Comple

Systematic Atmospheric Refreaction Errors of Baseline Type Radio Tracking Systems and Methods for their Correction

The theory of systematic atmospheric radio refraction errors affecting measurements of range and range differences (and associated time rate of change of these quantities) is developed. It is shown that the refraction errors, particularly in range difference measurements, can seriously affect the accuracy of baseline-type tracking systems. A method is derived by which the systematic portion of tL.ese errors can be removed by means of linear relationships involving the surface value of the radio refractive index; the correction process cievlsea can be used in real time if desired. Several test cases are examined where horizontally-varying profiles of the refractive index variation with height are used to calculate the errors, and the correction process based on surface refractive index values is found to be useful under these more general conditions. Approximately 98 percent of the total range or rangt difference error can be removed using this correction procedure. The problem of baseline optimization for deep-space tracking is examined briefly, and it is shown that a baseline length of about 4, 000 miles is optimal for targets more than about 6, 000 miles from the earth, and foi such a system residual atmospheric refraction errors would be only a fe\\ hundredths of a microradian, assuming the validity of ray optics and of the models of the atmosphere used in this paper

Unexpected Economic Loss from Yield Variation and Federal Crop Insurance

Multiple Peril Crop Insurance (MPCl) and GroupRisk Plan (GRP) use yield (i.e., physical) loss to determine who collects. However, insurance is bought to protect against economic loss resulting from physical loss. This study analyzes unexpected economic loss resulting from yield variation. It also compares unexpected economic loss with simulated MPCI and GRP collections for a sample of Ohio farm operators, Analysis reveals: (I) GRP's payout structure is further removed from unexpected economic loss than MPCrs, (2) MPCI collections exceed the associated unexpected economic loss in a free market, and (3) MPCI collections more closely match unexpected loss when farm programs exist