1,915 research outputs found
A calculational approach to electron impact excitation of ions in hot solar plasmas
The cross section requirements are presented for studying UV and X-ray emission spectra associated with active and flare-produced plasmas in the sun's corona. The general approach to the calculation of the distorted wave approximation problem is also given
The energy distribution cross section in threshold electron-atom impact ionization
The flatness of the energy differential cross section in impact ionization is derived analytically in the Wannier theory. However it is shown that the Wannier zone is confined to a region of the order E/5 is less than or equal to epsilon is less than or equal to 4E/5, where E is the available energy and epsilon is the energy of the electrons. By contrasting the known results of photoionization and photodetachment, one can cogently argue that in the complementary region where electrons share their energy very unequally the cross section rises to a value independent of E, and that this region determines the form of the threshold law
Electron-Hydrogen Phase Shifts Just Below the Inelastic Threshold
Electron-hydrogen phase shift below inelastic threshol
Hybrid theory and calculation of e-N2 scattering
A theory of electron-molecule scattering was developed which was a synthesis of close coupling and adiabatic-nuclei theories. The theory is shown to be a close coupling theory with respect to vibrational degrees of freedom but is a adiabatic-nuclei theory with respect to rotation. It can be applied to any number of partial waves required, and the remaining ones can be calculated purely in one or the other approximation. A theoretical criterion based on fixed-nuclei calculations and not on experiment can be given as to which partial waves and energy domains require the various approximations. The theory allows all cross sections (i.e., pure rotational, vibrational, simultaneous vibration-rotation, differential and total) to be calculated. Explicit formulae for all the cross sections are presented
Tabulation of hybrid theory calculated e-N2 vibrational and rotational cross sections
Vibrational excitation cross sections of N2 by electron impact are tabulated. Integrated cross sections are given for transitions v yields v prime where o=or v=or 8 in the energy range 0.1 eV=or E=or 10 eV. The energy grid is chosen to be most dense in the resonance region (2 to 4 eV) so that the substructure is present in the numerical results. Coefficients in the angular distribution formula (differential scattering cross section) for transitions v=0 yields v prime = or 8 are also numerically given over the same grid of energies. Simultaneous rotation-vibration coefficients are also given for transitions v=o,j=o; 1 yields v prime=o, j=o,2,4; 1,3,5. All results are obtained from the hybrid theory
Melting of alloys along the inter-phase boundaries in eutectic and peritectic systems
We discuss a simple model of the melting kinetics along the solid-solid
interface in eutectic and peritectic systems. The process is controlled by the
diffusion inside the liquid phase and the existence of a triple junction is
crucial for the velocity selection problem. Using the lubrication approximation
for the diffusion field in the liquid phase we obtain scaling results for the
steady-state velocity of the moving pattern depending on the overheating above
the equilibrium temperature and on the material parameters of the system,
including the dependences on the angles at the triple junction
Nonadiabatic theory of inelastic electron- hydrogen scattering
Nonadiabatic theory application to inelastic S-wave scattering of low energy electrons from atomic hydroge
National Foreclosure Mitigation Counseling Program Evaluation: Final Report, Rounds 1 and 2
The National Foreclosure Mitigation Counseling (NFMC) program is a special federal appropriation, administered by NeighborWorks (NW) America, to support a rapid expansion of foreclosure intervention counseling in response to the nationwide foreclosure crisis. As this is a federal appropriation, NW America must inform Congress and other entities of the NFMC program's progress. The Urban Institute (UI) was selected by NW America to evaluate the NFMC program. This report presents the final results from UI's evaluation of the first two rounds of the NFMC program (people receiving counseling in 2008 and 2009), including a detailed analysis of program outcomes first described in preliminary reports of November 2009 (Mayer et al.) and December 2010 (Mayer et al.). According to those reports, homeowners receiving NFMC counseling avoided entering foreclosure, successfully cured existing foreclosures, and obtained more favorable loan modifications. This report updates previous analyses and also includes revised models of several homeowner outcomes for NFMC clients counseled in 2008 and 2009. These new models use an improved comparison sample selection design, which addressed potential issues raised by reviewers of earlier analyses, and a better method for controlling for possible selection bias in the NFMC sample. The additional analyses in this report include models of non-modification cures, non-modification redefaults, and foreclosures avoided
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