2,356 research outputs found

    China\u27s Military Mercantilism

    Get PDF

    Coming together in a rightward direction:post-1980s changing attitudes to the British welfare state

    Get PDF
    Major changes in the British welfare state were initiated during the 1980s in response to the 1970s’ stagflation, rapid globalisation and the government’s inability to ensure full employment: the relatively unrestricted payment of unemployment benefits was replaced by a jobseekers’ allowance with applicants obliged to seek work actively and, if required, undergo training. Public support for this shift lagged behind the policy introductions, but from 1997 on there was a major change in attitudes towards welfare beneficiaries. Analysis of social attitude survey data for 1983-2011 shows this change occurred during the decade of relative prosperity under the New Labour governments. There was a growing concentration of anti-welfare attitudes across all social groups, regions and supporters of the main political parties

    British political values, attitudes to climate change, and travel behaviour

    Get PDF
    The UK is committed to a sharp reduction of greenhouse gases. Progress towards its goal will depend on whether the public can be persuaded to change their travel behaviour. Using British Social Attitudes 2011 survey data, analyses show that the majority of adults – especially the young and better-educated – believe that climate change is occurring but even concerned believers appear reluctant to modify their behaviour. Policies designed to alter transport habits and induce behaviour change need to take that clear conclusion into account. Without a strong political commitment, substantial change that will significantly mitigate the processes appears unlikely

    Study of Aerothermodynamic Modeling Issues Relevant to High-Speed Sample Return Vehicles

    Get PDF
    This paper examines the application of state-of-the-art coupled ablation and radiation simulations to highspeed sample return vehicles, such as those returning from Mars or an asteroid. A defining characteristic of these entries is that the surface recession rates and temperatures are driven by nonequilibrium convective and radiative heating through a boundary layer with significant surface blowing and ablation products. Measurements relevant to validating the simulation of these phenomena are reviewed and the Stardust entry is identified as providing the best relevant measurements. A coupled ablation and radiation flowfield analysis is presented that implements a finite-rate surface chemistry model. Comparisons between this finite-rate model and a equilibrium ablation model show that, while good agreement is seen for diffusion-limited oxidation cases, the finite-rate model predicts up to 50% lower char rates than the equilibrium model at sublimation conditions. Both the equilibrium and finite rate models predict significant negative mass flux at the surface due to sublimation of atomic carbon. A sensitivity analysis to flowfield and surface chemistry rates show that, for a sample return capsule at 10, 12, and 14 km/s, the sublimation rates for C and C3 provide the largest changes to the convective flux, radiative flux, and char rate. A parametric uncertainty analysis of the radiative heating due to radiation modeling parameters indicates uncertainties ranging from 27% at 10 km/s to 36% at 14 km/s. Applying the developed coupled analysis to the Stardust entry results in temperatures within 10% of those inferred from observations, and final recession values within 20% of measurements, which improves upon the 60% over-prediction at the stagnation point obtained through an uncoupled analysis. Emission from CN Violet is shown to be over-predicted by nearly and order-of-magnitude, which is consistent with the results of previous independent analyses. Finally, the coupled analysis is applied to a 14 km/s Earth entry representative of a Mars sample return. Although the radiative heating provides a larger fraction of the total heating, the influence of ablation and radiation on the flowfield are shown to be similar to Stardust

    Uncertainty Analysis of Air Radiation for Lunar Return Shock Layers

    Get PDF
    By leveraging a new uncertainty markup technique, two risk analysis methods are used to compute the uncertainty of lunar-return shock layer radiation predicted by the High temperature Aerothermodynamic Radiation Algorithm (HARA). The effects of epistemic uncertainty, or uncertainty due to a lack of knowledge, is considered for the following modeling parameters: atomic line oscillator strengths, atomic line Stark broadening widths, atomic photoionization cross sections, negative ion photodetachment cross sections, molecular bands oscillator strengths, and electron impact excitation rates. First, a simplified shock layer problem consisting of two constant-property equilibrium layers is considered. The results of this simplified problem show that the atomic nitrogen oscillator strengths and Stark broadening widths in both the vacuum ultraviolet and infrared spectral regions, along with the negative ion continuum, are the dominant uncertainty contributors. Next, three variable property stagnation-line shock layer cases are analyzed: a typical lunar return case and two Fire II cases. For the near-equilibrium lunar return and Fire 1643-second cases, the resulting uncertainties are very similar to the simplified case. Conversely, the relatively nonequilibrium 1636-second case shows significantly larger influence from electron impact excitation rates of both atoms and molecules. For all cases, the total uncertainty in radiative heat flux to the wall due to epistemic uncertainty in modeling parameters is 30% as opposed to the erroneously-small uncertainty levels (plus or minus 6%) found when treating model parameter uncertainties as aleatory (due to chance) instead of epistemic (due to lack of knowledge)
    • …
    corecore