366 research outputs found

    Selling the Korean War: Propaganda, Politics, and Public Opinion, 1950–1953

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    The far left and the far right have some- thing in common, especially when their enemies hold the White House. They each tend to think that the president can get away with anything, because he controls the media and the media con- trols the public, especially when it comes to issues of war. Professor Steven Casey of the London School of Eco- nomics actually knows something about this topic, usually the realm of strong opinions based on strong prejudice. In 2000 Casey wrote perhaps the most perceptive study ever published on presidential policy and public opinion during World War II

    Agents of Innovation: The General Board andthe Design of the Fleet That Defeated the Japanese Navy

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    Skeptics of disarmament treaties, such as Richard Pearl, have long argued that these treaties make a nation weaker by depriving it of the means of self-defense. John Kuehn, former naval aviator and presently professor of military history at the U.S. Army Command and General Staff College, in Fort Leaven- worth, Kansas, is far more subtle in this excellent book. He shows how the Washington Naval Treaty of 1921 froze battleship construction and yet made the U.S. Navy stronger by 1941. While it is never easy to prove something so counterintuitive, Kuehn does it hands down

    Great Britian, 1828-1834: Historiography and Selected Bibliography

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    http://deepblue.lib.umich.edu/bitstream/2027.42/50934/1/159.pd

    Satellite Laser Ranging operations

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    Satellite Laser Ranging (SLR) is currently providing precision orbit determination for measurements of: 1) Ocean surface topography from satellite borne radar altimetry, 2) Spatial and temporal variations of the gravity field, 3) Earth and ocean tides, 4) Plate tectonic and regional deformation, 5) Post-glacial uplift and subsidence, 6) Variations in the Earth's center-of-mass, and 7) Variations in Earth rotation. SLR also supports specialized programs in time transfer and classical geodetic positioning, and will soon provide precision ranging to support experiments in relativity

    Cool Flames at Terrestrial, Partial, and Near-Zero Gravity

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    Natural convection plays an important role in all terrestrial, Lunar, and Martian-based, unstirred, static reactor cool flame and low-temperature autoignitions, since the Rayleigh number (Ra) associated with the self-heating of the reaction exceeds the critical Ra (approximately 600) for onset of convection. At near-zero gravity, Ra \u3c 600 can be achieved and the effects of convection suppressed. To systematically vary the Ra without varying the mixture stoichiometry, reactor pressure, or vessel size, cool flames are studied experimentally in a closed, unstirred, static reactor subject to different gravitational accelerations (terrestrial, 1g; Martian, 0.38g; Lunar, 0.16g; a n dr e - duced gravity, ∼10−2g). Representative results show the evolution of the visible light emission using an equimolar n-butane:oxygen premixture at temperatures ranging from 320 to 350 ◦C (593–623 K) at subatmospheric pressures. For representative reduced-gravity, spherically propagating cool flames, the flame radius based on the peak light intensity is plotted as a function of time and the flame radius (and speed) is calculated from a polynomial fit to data. A skeletal chemical kinetic Gray-Yang model developed previously for a one-dimensional, reactive– diffusive system by Fairlie and co-workers is extended to a two-dimensional axisymmetric, spherical geometry. The coupled species, energy, and momentum equations are solved numerically and the spatio-temporal variations in the temperature profiles are presented. A qualitative comparison is made with the experimental results

    Cool Flame Propagation Speeds

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    Cool flames are studied at reduced-gravity in a closed, unstirred, spherical reactor to minimize complexities associated with natural convection. Under such conditions, transport is controlled by diffusive fluxes and the flames are observed to propagate radially outward from the center of the reactor toward the wall. Intensified video records are obtained and analyzed to determine the flame radius as a function of time for different vessel temperatures (593–623 K) and initial pressures (55.2–81.4 kPa) using an equimolar (Ø = 5) propane-oxygen premixture. Polynomial-fits are applied to the data and differentiated to determine the cool flame propagation speeds. In nearly all cases considered, the flame decelerates monotonically and in some cases, subsequently retreats towards the center of the reactor. The flame speed is also tabulated as a function of the flame stretch rate. Extrapolation of the cool flame speeds to zero stretch is then performed to determine the ‘‘unstretched’’ cool flame propagation speeds

    Non-Isothermal Cool Flames in Unstirred Static Reactors: A Compressible Model with Global Kinetics

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    A compressible model is developed with kinetics based on the Wang–Mou five-step global kinetic scheme and used to evaluate the temperature, concentration, and velocity fields characteristic of low temperature combustion in unstirred static reactors. This work relaxes the assumption of small exothermicity that enabled prior studies to employ the Boussinesq approximation, valid for cases where BT \u3c\u3c 1, i.e., slow reactions and cool flames. In this study, the range of validity of the model is extended to cases with large temperature excursions, including multi-stage ignition. For the weakly exothermic cases considered, including modes of slow reaction and cool flames, the Boussinesq approximation is completely adequate. However, it overpredicts the density change and underpredicts the ignition delay time for high-temperature ignitions. Qualitative comparison with experimental results acquired at microgravity conditions are also discussed

    An Existing Global Heptane Mechanism Augmented with Diffusive Transport

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    The couplings between diffusive transport and the temperature and species concentration distributions associated with low and intermediate temperature heptane oxidation are explored using an existing four-step heptane mechanism, tuned for elevated pressures. The energy and species concentration equations are augmented with diffusive fluxes for heat and species and solved numerically in a one-dimensional domain. The ignition delay times are also tabulated and compared with the zero-dimensional data reported in the literature
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