Particle kinetic simulation of high altitude hypervelocity flight

In this grant period, the focus has been on the effects of thermo-chemical nonequilibrium in low-density gases, and on interactions between such gases and solid surfaces. Such conditions apply to hypersonic flows of re-entry vehicles, and to the expansion plumes of small rockets. Due to the nonequilibrium nature of these flows, a particle approach has been adopted. The method continues to undergo refinement and application to typical flows of interest. A number of studies have been performed for flows in thermo-chemical nonequilibrium. The effects of vibrational nonequilibrium on the rate of dissociation were studied for diatomic nitrogen. It was found that a new model reproduced the nonequilibrium behavior observed experimentally

The uniting of Europe and the foundation of EU studies: revisiting the neofunctionalism of Ernst B. Haas

This article suggests that the neofunctionalist theoretical legacy left by Ernst B. Haas is somewhat richer and more prescient than many contemporary discussants allow. The article develops an argument for routine and detailed re-reading of the corpus of neofunctionalist work (and that of Haas in particular), not only to disabuse contemporary students and scholars of the normally static and stylized reading that discussion of the theory provokes, but also to suggest that the conceptual repertoire of neofunctionalism is able to speak directly to current EU studies and comparative regionalism. Neofunctionalism is situated in its social scientific context before the theory's supposed erroneous reliance on the concept of 'spillover' is discussed critically. A case is then made for viewing Haas's neofunctionalism as a dynamic theory that not only corresponded to established social scientific norms, but did so in ways that were consistent with disciplinary openness and pluralism

Neutrino-driven Turbulent Convection and Standing Accretion Shock Instability in Three-Dimensional Core-Collapse Supernovae

We conduct a series of numerical experiments into the nature of three-dimensional (3D) hydrodynamics in the postbounce stalled-shock phase of core-collapse supernovae using 3D general-relativistic hydrodynamic simulations of a $27$-$M_\odot$ progenitor star with a neutrino leakage/heating scheme. We vary the strength of neutrino heating and find three cases of 3D dynamics: (1) neutrino-driven convection, (2) initially neutrino-driven convection and subsequent development of the standing accretion shock instability (SASI), (3) SASI dominated evolution. This confirms previous 3D results of Hanke et al. 2013, ApJ 770, 66 and Couch & Connor 2014, ApJ 785, 123. We carry out simulations with resolutions differing by up to a factor of $\sim$4 and demonstrate that low resolution is artificially favorable for explosion in the 3D convection-dominated case, since it decreases the efficiency of energy transport to small scales. Low resolution results in higher radial convective fluxes of energy and enthalpy, more fully buoyant mass, and stronger neutrino heating. In the SASI-dominated case, lower resolution damps SASI oscillations. In the convection-dominated case, a quasi-stationary angular kinetic energy spectrum $E(\ell)$ develops in the heating layer. Like other 3D studies, we find $E(\ell) \propto \ell^{-1}$ in the "inertial range," while theory and local simulations argue for $E(\ell) \propto \ell^{-5/3}$. We argue that current 3D simulations do not resolve the inertial range of turbulence and are affected by numerical viscosity up to the energy containing scale, creating a "bottleneck" that prevents an efficient turbulent cascade.Comment: 24 pages, 15 figures. Accepted for publication in The Astrophysical Journal. Added one figure and made minor modifications to text according to suggestions from the refere

Application of remote sensing to study nearshore circulation

The research to use remote sensing techniques for studying the continental shelf is reported. The studies reported include: (1) nearshore circulation in the vincinity of a natural tidal inlet; (2) identification of indicators of biological activity; (3) remote navigation system for tracking free drifting buoys; (4) experimental design of an estuaring tidal circulation; and (5) Skylab support work

Phase diagram of hot magnetized two-flavor color superconducting quark matter

A two-flavor color superconducting (2SC) Nambu--Jona-Lasinio (NJL) model is introduced at finite temperature T, chemical potential mu and in the presence of a constant magnetic field eB. The effect of (T,mu,eB) on the formation of chiral and color symmetry breaking condensates is studied. The complete phase portrait of the model in T-mu, mu-eB, and T-eB phase spaces for various fixed eB, T, and mu is explored. A threshold magnetic field eB_t~ 0.5 GeV^2 is found above which the dynamics of the system is solely dominated by the lowest Landau level (LLL) and the effects of T and mu are partly compensated by eB.Comment: V1: 29 pages, 15 figures, 3 tables. V2: Discussions improved. Version accepted for publication in PR

Properties of neutral mesons in a hot and magnetized quark matter

The properties of non-interacting $\sigma$ and $\pi^{0}$ mesons are studied at finite temperature, chemical potential and in the presence of a constant magnetic field. To do this, the energy dispersion relations of these particles, including nontrivial form factors, are derived using a derivative expansion of the effective action of a two-flavor, hot and magnetized Nambu--Jona-Lasinio (NJL) model up to second order. The temperature dependence of the pole and screening masses as well as the directional refraction indices of magnetized neutral mesons are explored for fixed magnetic fields and chemical potentials. It is shown that, because of the explicit breaking of the Lorentz invariance by the magnetic field, the refraction index and the screening mass of neutral mesons exhibit a certain anisotropy in the transverse and longitudinal directions with respect to the direction of the external magnetic field. In contrast to their longitudinal refraction indices, the transverse indices of the neutral mesons are larger than unity.Comment: V1: 26 pages, 15 figures; V2: Discussions improved, references added. Version accepted for publication in PR