26,959 research outputs found
The interplanetary magnetic field
Large-scale properties of the interplanetary magnetic field as determined by the solar wind velocity structure are examined. The various ways in which magnetic fields affect phenomena in the solar wind are summarized. The dominant role of high and low velocity solar wind streams that persist, with fluctuations and evolution, for weeks or months is emphasized. It is suggested that for most purposes the sector structure is better identified with the stream structure than with the magnetic polarity and that the polarity does not necessarily change from one velocity sector to the next. Several mechanisms that might produce the stream structure are considered. The interaction of the high and low velocity streams is analyzed in a model that is steady state when viewed in a frame that corotates with the sun
Before Virtue: Halakhah, Dharmasastra, and What Law Can Create
Davis, referring to the traditional Jewish and Hindu legal texts, addresses on what law creates or produces. He focuses on both Jewish and Hindu jurisprudence claim that law can create--a human, not a biological homo sapiens, but rather the full ideal of what humans were meant to be. He argues that it is the essential indistinguishability of law and religion in both traditional Judaism and Hinduism that permits the ideal human to be created through religious law
The Evolution of Neutrino Astronomy
How did neutrino astronomy evolve? Are there any useful lessons for
astronomers and physicists embarking on new observational ventures today? We
answer the first question; the reader can can decide if there are any useful
parallels for other fields.Comment: Figures added in editorial stage. Related material
http://www.sns.ias.edu/~jnb/Papers/Popular/snhistory.htm
Detailed analysis and test correlation of a stiffened composite wing panel
Nonlinear finite element analysis techniques are evaluated by applying them to a realistic aircraft structural component. A wing panel from the V-22 tiltrotor aircraft is chosen because it is a typical modern aircraft structural component for which there is experimental data for comparison of results. From blueprints and drawings supplied by the Bell Helicopter Textron Corporation, a very detailed finite element model containing 2284 9-node Assumed Natural-Coordinate Strain (ANS) elements was generated. A novel solution strategy which accounts for geometric nonlinearity through the use of corotating element reference frames and nonlinear strain displacements relations is used to analyze this detailed model. Results from linear analyses using the same finite element model are presented in order to illustrate the advantages and costs of the nonlinear analysis as compared with the more traditional linear analysis. Strain predictions from both the linear and nonlinear stress analyses are shown to compare well with experimental data up through the Design Ultimate Load (DUL) of the panel. However, due to the extreme nonlinear response of the panel, the linear analysis was not accurate at loads above the DUL. The nonlinear analysis more accurately predicted the strain at high values of applied load, and even predicted complicated nonlinear response characteristics, such as load reversals, at the observed failure load of the test panel. In order to understand the failure mechanism of the panel, buckling and first ply failure analyses were performed. The buckling load was 17 percent above the observed failure load while first ply failure analyses indicated significant material damage at and below the observed failure load
Fabrication of uniaxial filament-reinforced epoxy tubes for structural application
Filament reinforced composite materials have high strength, high stiffness and low density. Tubes fabricated from process described have advantages of having smooth inner and outer surfaces, lower dimensional variation than tolerances set for extruded aluminum tubing and void free composites
Acceleration of Electrons near the Earth's Bow Shock
Accleration mechanism of electron plasma outside magnetosphere near bow shock regio
Analysis of shear test method for composite laminates
An elastic plane stress finite element analysis of the stress distributions in four flat test specimens for in-plane shear response of composite materials subjected to mechanical or thermal loads is presented. The shear test specimens investigated include: slotted coupon, cross beam, losipescu, and rail shear. Results are presented in the form of normalized shear contour plots for all three in-plane stess components. It is shown that the cross beam, losipescu, and rail shear specimens have stress distributions which are more than adequate for determining linear shear behavior of composite materials. Laminate properties, core effects, and fixture configurations are among the factors which were found to influence the stress distributions
Design detail verification tests for a lightly loaded open-corrugation graphite-epoxy cylinder
Flat corrugated graphite-epoxy panels were tested in compression to verify selected design details of a ring-stiffened cylinder that was designed to support an axial compressive load of 157.6 kN/m without buckling. Three different sizes of subcomponent panels, with the same basic corrugation geometry, were tested: (1) 60.96-cm-long by 45.72-cm-wide panels to evaluate the local buckling strength of the shell wall design; (2) 91.44-cm-long by 45.72-cm-wide panels to evaluate a longitudinal joint and the load-introduction method; and (3) 254.0-cm-long by 91.44-cm-wide panels with four simulated-ring stiffeners to evaluate the ring-attachment method. The test results indicate that the modified shell-wall design, the longitudinal joint, the load-introduction method, and the stiffener-attachment method for the proposed cylinder have adequate strength to support the design load
Summary of the electromagnetic compatibility evaluation of the proposed satellite power system
The effects of the proposed solar power satellite (SPS) operations on electronic equipment and systems by fundamental, harmonic, and intermodulation component emissions from the orbital station; and the fundamental, harmonic, and structural intermodulation emissions from the rectenna site were evaluated. The coupling and affects interactions affecting a wide spectrum of electronic equipment are considered. The primary EMC tasking areas are each discussed separately
Partial versus General Equilibrium Calorie and Revenue Effects of a Sugar-Sweetened Beverage Tax
The current obesity crisis in the United States is generating numerous alternative policy options for combating the problem. One alternative that has been widely proposed is an excise or sales tax on sugar-sweetened non-alcoholic beverages. This literature started out within a very simple partial equilibrium framework. Not considering the feedback effects (or general equilibrium effects) across interrelated market is a shortcoming of these partial equilibrium analyses. Our study is carried out to ascertain stochastic partial and general equilibrium calorie, body weight and revenue effects of a tax on sugar-sweetened beverages as well as incidence of such tax. We used Nielsen Homescan data on prices and quantities of selected non-alcoholic beverages purchased over the period January 1998 through December 2008. Probability density functions (pdfs) generated using simulations of calorie outcomes reveal that the calorie reduction due to tax on sugar-sweetened beverages is between 465 and 716 calories per person per month. However, consideration of both direct and indirect effects in generating the effect of the tax on sugar-sweetened beverages reveal reduction as low as 199 calories per person per month and as high as707 calories per person per month.Partial equilibrium, general equilibrium, tax effects, sugar-sweetened beverages, beverage tax, calorie effects, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Health Economics and Policy, D11, D12, I18,
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