38,313 research outputs found
FINANCIAL ANALYSIS OF A PROPOSED LARGE-SCALE ETHANOL COGENERATION PROJECT
Financial analysis of an ethanol/electricity cogeneration plant indicates a rapid payback of investment and a high internal rate of return. This is primarily because cogeneration of steam for generation of electricity and biomass conversion to ethanol results in increased engineering efficiency compared to alternative ethanol alone production processes. Economic sensitivity testing included alternative price levels, interest rates, capacities, costs, and a "stand alone" case with no federal government excise tax subsidies. Supply and price analyses suggest the procurement of locally produced feedstock in Alabama and surrounding states is feasible. The robustness of the economic analysis provides support for consideration of ethanol cogeneration as a currently feasible strategy to utilize excess agricultural production capacity.Resource /Energy Economics and Policy,
Reflection of a shock wave into a density gradient
Linear density variation from nonuniform flow behind shock wav
Extragalactic Foreground Contamination in Temperature-based CMB Lens Reconstruction
We discuss the effect of unresolved point source contamination on estimates
of the CMB lensing potential, from components such as the thermal
Sunyaev-Zel'dovich effect, radio point sources, and the Cosmic Infrared
Background. We classify the possible trispectra associated with such source
populations, and construct estimators for the amplitude and scale-dependence of
several of the major trispectra. We show how to propagate analytical models for
these source trispectra to biases for lensing. We also construct a
"source-hardened" lensing estimator which experiences significantly smaller
biases when exposed to unresolved point sources than the standard quadratic
lensing estimator. We demonstrate these ideas in practice using the sky
simulations of Sehgal et. al., for cosmic-variance limited experiments designed
to mimic ACT, SPT, and Planck
Unified aeroacoustics analysis for high speed turboprop aerodynamics and noise. Volume 5: Propagation of propeller tone noise through a fuselage boundary layer
An analysis of tone noise propagation through a boundary layer and fuselage scattering effects was derived. This analysis is a three dimensional and the complete wave field is solved by matching analytical expressions for the incident and scattered waves in the outer flow to a numerical solution in the boundary layer flow. The outer wave field is constructed analytically from an incident wave appropriate to the source and a scattered wave in the standard Hankel function form. For the incident wave, an existing function - domain propeller noise radiation theory is used. In the boundary layer region, the wave equation is solved by numerical methods. The theoretical analysis is embodied in a computer program which allows the calculation of correction factors for the fuselage scattering and boundary layer refraction effects. The effects are dependent on boundary layer profile, flight speed, and frequency. Corrections can be derived for any point on the fuselage, including those on the opposite side from the source. The theory was verified using limited cases and by comparing calculations with available measurements from JetStar tests of model prop-fans. For the JetStar model scale, the boundary layer refraction effects produce moderate fuselage pressure reinforcements aft of and near the plane of rotation and significant attenuation forward of the plane of rotation at high flight speeds. At lower flight speeds, the calculated boundary layer effects result in moderate amplification over the fuselage area of interest. Apparent amplification forward of the plane of rotation is a result of effective changes in the source directivity due to boundary layer refraction effects. Full scale effects are calculated to be moderate, providing fuselage pressure amplification of about 5 dB at the peak noise location. Evaluation using available noise measurements was made under high-speed, high-altitude flight conditions. Comparisons of calculations made of free field noise, using a current frequency-domain propeller noise prediction method, and fuselage effects using this new procedure show good agreement with fuselage measurements over a wide range of flight speeds and frequencies. Correction factors for the JetStar measurements made on the fuselage are provided in an Appendix
DIVERSITY OF SOURCES FOR FRESH PRODUCE: IMPLICATIONS FOR LOCAL MARKETS
Number of suppliers, approximation of equal-shares market condition and market share held by in-state sources were calculated to determine diversity of sources for 10 fresh fruits and vegetables in eight U.S. wholesale markets. Specificity of growing conditions is associated with few supply sources, unequal market shares and limited purchases from in-state suppliers. For crops with few sources, lower perishability and greater transportability are correlated with greater balance in market shares. For crops with many supply sources, greater perishability and greater transportability are consistent with large market share from imports. Diversity across all commodities can increase market share for local producers.Concentration index, Fruits and vegetables, Source diversity, Marketing,
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