From Microscales to Macroscales in 3D: Selfconsistent Equation of State for Supernova and Neutron Star Models

First results from a fully self-consistent, temperature-dependent equation of state that spans the whole density range of neutron stars and supernova cores are presented. The equation of state (EoS) is calculated using a mean-field Hartree-Fock method in three dimensions (3D). The nuclear interaction is represented by the phenomenological Skyrme model in this work, but the EoS can be obtained in our framework for any suitable form of the nucleon-nucleon effective interaction. The scheme we employ naturally allows effects such as (i) neutron drip, which results in an external neutron gas, (ii) the variety of exotic nuclear shapes expected for extremely neutron heavy nuclei, and (iii) the subsequent dissolution of these nuclei into nuclear matter. In this way, the equation of state is calculated across phase transitions without recourse to interpolation techniques between density regimes described by different physical models. EoS tables are calculated in the wide range of densities, temperature and proton/neutron ratios on the ORNL NCCS XT3, using up to 2000 processors simultaneously.Comment: 6 pages, 11 figures. Published in conference proceedings Journal of Physics: Conference Series 46 (2006) 408. Extended version to be submitted to Phys. Rev.

Finite Nuclei in the Quark-Meson Coupling (QMC) Model

We report the first use of the effective QMC energy density functional (EDF), derived from a quark model of hadron structure, to study a broad range of ground state properties of even-even nuclei across the periodic table in the non-relativistic Hartree-Fock+BCS framework. The novelty of the QMC model is that the nuclear medium effects are treated through modification of the internal structure of the nucleon. The density dependence is microscopically derived and the spin-orbit term arises naturally. The QMC EDF depends on a single set of four adjustable parameters having clear physical basis. When applied to diverse ground state data the QMC EDF already produces, in its present simple form, overall agreement with experiment of a quality comparable to a representative Skyrme EDF. There exist however multiple Skyrme paramater sets, frequently tailored to describe selected nuclear phenomena. The QMC EDF set of fewer parameters, as derived in this work, is not open to such variation, chosen set being applied, without adjustment, to both the properties of finite nuclei and nuclear matter.Comment: 9 pages, 1 table, 4 figures; in print in Phys. Rev. Letters. A minor change in the abstract, a few typos corrected and some small technical adjustments made to comply with the journal regulation

Intravascular Imaging Guidance of Left Main PCI: Nice to Have or Must Have?

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Flight test evaluation of a separate surface attitude command control system on a Beech 99 airplane

A joint NASA/university/industry program was conducted to flight evaluate a potentially low cost separate surface implementation of attitude command in a Beech 99 airplane. Saturation of the separate surfaces was the primary cause of many problems during development. Six experienced professional pilots who made simulated instrument flight evaluations experienced improvements in airplane handling qualities in the presence of turbulence and a reduction in pilot workload. For ride quality, quantitative data show that the attitude command control system results in all cases of airplane motion being removed from the uncomfortable ride region

Field Dependent Phase Diagram of the Quantum Spin Chain (CH3)2NH2CuCl3

Although (CH3)2NH2CuCl3 (MCCL) was first examined in the 1930's [1], there are open questions regarding the magnetic dimensionality and nature of the magnetic properties. MCCL is proposed to be a S=1/2 alternating ferromagnetic antiferromagnetic spin chain alternating along the crystalline a-axis [2,3]. Proposed ferromagnetic (JFM =1.3 meV) and antiferromagnetic (JAFM =1.1 meV) exchange constants make this system particularly interesting for experimental study. Because JFM and JAFM are nearly identical, the system should show competing behavior between S=1/2 (AFM) and S=1(FM) effects. We report low temperature magnetic field dependent susceptibility, chi(H), and specific heat, Cp, of MCCL. These provide an initial magnetic-field versus temperature phase diagram. A zero-field phase transition consistent with long range magnetic order is observed at T=0.9 K. The transition temperature can be reduced via application of a magnetic field. We also present comparisons to a FM/AFM dimer model that accounts for chi(T,H=0) and Cp(H,T).Comment: 2 pages, 1 figure included in text. Submitted to proceedings of 24th International Conference on Low Temperature Physics, August 200

Edge helicons and repulsion of fundamental edge magnetoplasmons in the quantum Hall regime

A quasi-microscopic treatment of edge magnetoplasmons (EMP) is presented for very low temperatures and confining potentials smooth on the scale of the magnetic length $\ell_{0}$ but sufficiently steep at the edges such that Landau level (LL) flattening can be discarded. The profile of the unperturbed electron density is sharp and the dissipation taken into account comes only from electron intra-edge and intra-LL transitions due to scattering by acoustic phonons. For wide channels and filling factors $\nu =1$ and 2, there exist independent EMP modes spatially symmetric and antisymmetric with respect to the edge. Some of these modes, named edge helicons, can propagate nearly undamped even when the dissipation is strong. Their density profile changes qualitatively during propagation and is given by a rotation of a complex vector function. For $\nu >2,$ the Coulomb coupling between the LLs leads to a repulsion of the uncoupled fundamental LL modes: the new modes have very different group velocities and are nearly undamped. The theory accounts well for the experimentally observed plateau structure of the delay times as well as for the EMP's period and decay rates.Comment: 12 pages, 6 figure

Fast drift kilometric radio bursts and solar proton events

Initial results of a comparative study of major fast drift kilometric bursts and solar proton events from Sep. 1978 to Feb. 1983 are presented. It was found that only about half of all intense, long duration ( 40 min above 500 sfu) 1 MHz bursts can be associated with F 20 MeV proton events. However, for the subset of such fast drift bursts accompanied by metric Type 2 and/or 4 activity (approximately 40% of the total), the degree of association with 20 MeV events is 80%. For the reverse association, it was found that proton events with J( 20 MeV) 0.01 1 pr cm(-2)s(-1)sr(-1)MeV(-1) were typically (approximately 80% of the time) preceded by intense 1 MHz bursts that exceeded the 500 sfu level for times 20 min (median duration approximately 35 min)