The Anisoplanatic Point Spread Function in Adaptive Optics

The effects of anisoplanatism on the adaptive optics point spread function are investigated. A model is derived that combines observations of the guide star with an analytic formulation of anisoplanatism to generate predictions for the adaptive optics point spread function at arbitrary locations within the field of view. The analytic formulation captures the dependencies of anisoplanatism on aperture diameter, observing wavelength, angular offset, zenith angle and turbulence profile. The predictions of this model are compared to narrowband 2.12 um and 1.65 um images of a 21 arcsec binary (mV=7.3, 7.6) acquired with the Palomar Adaptive Optics System on the Hale 5 meter telescope. Contemporaneous measurements of the turbulence profile made with a DIMM/MASS unit are used together with images of the primary to predict the point spread function of the binary companion. Predicted companion Strehl ratios are shown to match measurements to within a few percent, whereas predictions based on the isoplanatic angle approximation are highly discrepant. The predicted companion point spread functions are shown to agree with observations to 10%. These predictions are used to measure the differential photometry between binary members to an accuracy of 1 part in 10^{3}, and the differential astrometry to an accuracy of 1 mas. Errors in the differential astrometry are shown to be dominated by differential atmospheric tilt jitter. These results are compared to other techniques that have been employed for photometry, astrometry, and high contrast imaging.Comment: 26 pages, 7 figure

Determining the Optimal Location for Collocating a Louisiana Sugar Mill and a New Cellulosic Ethanol Plant

This paper examines the possibility of collocating a cellulosic ethanol processing plant with certain Louisiana sugar mills, chosen based on their strategic locations and cane grinding capacity. The prospective plants are compared based on transportation costs and overall economic performance.cellulosic ethanol, advanced biofuels, sugarcane, energy cane, bioenergy, Agribusiness, Production Economics, Resource /Energy Economics and Policy, q16, q42,

The Economics of Processing Ethanol at Sugarmills: A Simulation Approach

Resource /Energy Economics and Policy,

Energy Cane Usage for Cellulosic Ethanol: Estimation of Feedstock Costs

Cellulosic Ethanol, Energy Cane, Sugarcane, Farm Management, Production Economics,

A Comparison of Pricing Strategies for Cellulosic Ethanol Processors: A Simulation Approach

Resource /Energy Economics and Policy,

Breaking into the Cellulosic Ethanol Market: Capacity and Storage Strategies

This paper examines the possibilities of breaking into the cellulosic ethanol market in south Louisiana via strategic feedstock choices and the leveraging of the area’s competitive advantages. A small plant strategy is devised whereby the first-mover problem might be solved, and several scenarios are tested using Net Present Value analysis.cellulosic ethanol, sugarcane, energy cane, sweet sorghum, bagasse, ethanol, biofuel, bioethanol, Agribusiness, Agricultural Finance, Crop Production/Industries, Production Economics, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy,

Inversion of spinning sound fields

A method is presented for the reconstruction of rotating monopole source distributions using acoustic pressures measured on a sideline parallel to the source axis. The method requires no \textit{a priori} assumptions about the source other than that its strength at the frequency of interest vary sinusoidally in azimuth on the source disc so that the radiated acoustic field is composed of a single circumferential mode. When multiple azimuthal modes are present, the acoustic field can be decomposed into azimuthal modes and the method applied to each mode in sequence. The method proceeds in two stages, first finding an intermediate line source derived from the source distribution and then inverting this line source to find the radial variation of source strength. A far-field form of the radiation integrals is derived, showing that the far field pressure is a band-limited Fourier transform of the line source, establishing a limit on the quality of source reconstruction which can be achieved using far-field measurements. The method is applied to simulated data representing wind-tunnel testing of a ducted rotor system (tip Mach number~0.74) and to control of noise from an automotive cooling fan (tip Mach number~0.14), studies which have appeared in the literature of source identification.Comment: Revised version of paper submitted to JASA; five more figures; expanded content with more discussion of error behaviour and relation to Nearfield Acoustical Holograph