135,945 research outputs found
Review of: Catherine Manton, Fed Up: Women and Food in America
A review of the book Fed Up: Women and Food in America by Catherine Manton (Bergin & Garvey 1999). Bibliography, index, notes. ISBN 0-89789-448-0 [184 pp. $55.00. Cloth, 88 Post Road West, Westport, CT 06881]
Book review of \u27Natural Premises: Ecology and Peasant Life in the Western Himalaya, 1800-1950\u27 by Chetan Singh
The sensitivity of willingness to pay to an economic downturn
Stated preference (SP) studies are typically undertaken at one point in time, while the results may be relied on in decision-making several months or even years later. This reliance is only justified if values are stable over time, an assumption which is doubtable given the onset of an economic downturn. We assess the reliability of values taken before an economic downturn for application during the downturn, via analysis of responses to two near identical surveys conducted respectively before and during the 2008-2010 economic recession. The surveys were valuing near identical sets of permanent water sector service and environmental improvements. Each survey employed a dichotomous choice and a payment card contingent valuation question. Our main result is that the economic downturn led to lower payment card responses but had no effect on the values elicited via a dichotomous choice (ie referendum-type) contingent valuation question. We explore potential explanations for this finding in light of the literature on closed-ended versus open-ended elicitation method comparisons
Developments and trends in three-dimensional mesh generation
An intense research effort over the last few years has produced several competing and apparently diverse methods for generating meshes. Recent progress is reviewed and the central themes are emphasized which form a solid foundation for future developments in mesh generation
Ground exposure of composite materials for helicopters
Residual strength results are presented on four composite material systems that were exposed for three years at locations on the North American Continent. The exposure locations are near the areas where Bell Model 206L Helicopters, that are in a NSA/U.S. Army sponsored flight service program, are flying in daily commercial service. The composite systems are: (1) Kevlar-49 fabric/F-185 epoxy; (2) Kevlar-49 fabric/LRF-277 epoxy; (3) Kevlar-49 fabric/CE-306 epoxy; and (4) T-300 Graphite/E-788 epoxy. All material systems exhibited good strength retention in compression and short beam shear. The Kevlar-49/LRF-277 epoxy retained 88 to 93 percent of the baseline strength while the other material systems exceeded 95 percent of baseline strength. Residual tensile strength of all materials did not show a significant reduction. The available moisture absorption data is also presented
Flight service evaluation of composite components on Bell 206L and Sikorsky S-76 helicopters
Progress on two programs to evaluate composite structural components in flight service on commercial helicopters is described. Thirty-six ship sets of composite components that include the litter door, baggage door, forward fairing, and vertical fin were installed on Bell Model 206L helicopters that are operating in widely different climatic areas. Four horizontal stabilizers and ten tail rotor spars that are production components on the S-76 helicopter were tested after prescribed periods of service to determine the effects of the operating environment on their performance. Concurrent with the flight evaluation, specimens from materials used to fabricate the components were exposed in ground racks and tested at specified intervals to determine the effects of outdoor environments. Results achieved from 14,000 hours of accumulated service on the 206L components, tests on a S-76 horizontal stabilizer after 1600 hours of service, tests on a S-76 tail rotor spar after 2300 hours service, and two years of ground based exposure of material coupons are reported
A split finite element algorithm for the compressible Navier-Stokes equations
An accurate and efficient numerical solution algorithm is established for solution of the high Reynolds number limit of the Navier-Stokes equations governing the multidimensional flow of a compressible essentially inviscid fluid. Finite element interpolation theory is used within a dissipative formulation established using Galerkin criteria within the Method of Weighted Residuals. An implicit iterative solution algorithm is developed, employing tensor product bases within a fractional steps integration procedure, that significantly enhances solution economy concurrent with sharply reduced computer hardware demands. The algorithm is evaluated for resolution of steep field gradients and coarse grid accuracy using both linear and quadratic tensor product interpolation bases. Numerical solutions for linear and nonlinear, one, two and three dimensional examples confirm and extend the linearized theoretical analyses, and results are compared to competitive finite difference derived algorithms
A city invests in its future
Events occurring during the past four years which led to the City of Burbank's decision to acquire an energy source adequate for the city's present and future power requirements are discussed. The community reaction to this unprecedented move is also covered. Burbank's long-range plans for the development of geothermal energy are outlined as well as the challenges which confront a public utility in implementing its projected goals. There are several advantages accurring to the city which in the opinion of the Burbank City Council and the administration justify this venture. The need for a cooperative climate which will enable all electrical utilities to better meet their obligations to the public, which is their prime responsibility before all other considerations, is analyzed
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