27,435 research outputs found
A numerical study of diffusive shock acceleration of cosmic rays in supernova shocks
The evolution of the energy spectrum of cosmic rays accelerated by the first order Fermi mechanism, by a supernova remnant shock wave, including adiabatic deceleration effects behind the front, is carried out by means of a time-dependent numerical code. The calculations apply to the adiabatic stage (or Sedov stage) of the supernova explosion, and the energetic particle spectrum is calculated in the test particle limit (i.e., the back reaction of the cosmic rays on the flow is not included). The particles are injected mono-energetically at the shock. The radial distribution, The radial distribution, and the spectrum of the accelerated and decelerated particles is shown
First axion dark matter search with toroidal geometry
We firstly report an axion haloscope search with toroidal geometry. In this
pioneering search, we exclude the axion-photon coupling
down to about GeV over the axion mass range from 24.7
to 29.1 eV at a 95\% confidence level. The prospects for axion dark matter
searches with larger scale toroidal geometry are also considered.Comment: 5 pages, 5 figures, 1 table and to appear in PRD-R
Buckling behavior of Rene 41 tubular panels for a hypersonic aircraft wing
The buckling characteristics of Rene 41 tubular panels for a hypersonic aircraft wing were investigated. The panels were repeatedly tested for buckling characteristics using a hypersonic wing test structure and a universal tension/compression testing machine. The nondestructive buckling tests were carried out under different combined load conditions and in different temperature environments. The force/stiffness technique was used to determine the buckling loads of the panel. In spite of some data scattering, resulting from large extrapolations of the data fitting curve (because of the termination of applied loads at relatively low percentages of the buckling loads), the overall test data correlate fairly well with theoretically predicted buckling interaction curves. Also, the structural efficiency of the tubular panels was found to be slightly higher than that of beaded panels
Particle correlations at RHIC from parton coalescence dynamics -- first results
A new dynamical approach that combines covariant parton transport theory with
hadronization channels via parton coalescence and fragmentation is applied to
Au+Au at RHIC. Basic consequences of the simple coalescence formulas, such as
elliptic flow scaling and enhanced proton/pion ratio, turn out to be rather
sensitive to the spacetime aspects of coalescence dynamics.Comment: Contribution to Quark Matter 2004 (January 11-17, 2004, Oakland, CA).
4 pages, 2 EPS figs, IOP style fil
In vitro micropropagation of white dasheen (Colocassia esculenta)
Plant regeneration for efficient vegetative propagation in white dasheen has been developed. Meristem cultured on Murashige and Skoog medium supplemented with 6-Benzyladenine (BA) and Indole-3-aceticacid (IAA) gave the best explants establishment and development. This in vitro system provides for a uniform production system which is easily managed and yields high quality cornels for commercial production
Discrete Morse functions for graph configuration spaces
We present an alternative application of discrete Morse theory for
two-particle graph configuration spaces. In contrast to previous constructions,
which are based on discrete Morse vector fields, our approach is through Morse
functions, which have a nice physical interpretation as two-body potentials
constructed from one-body potentials. We also give a brief introduction to
discrete Morse theory. Our motivation comes from the problem of quantum
statistics for particles on networks, for which generalized versions of anyon
statistics can appear.Comment: 26 page
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