Moving grid method without interpolations

In their method, to solve a one—dimensional moving boundary problem, Crank and Gupta suggest a grid system which moves with the Interface. The method requires some interpolations to be carried out which they perform by using a cubic spline or an ordinary polynomial. In the present paper these interpolations are avoided by employing a Taylor's expansion in space and time dimensions. A practical diffusion problem is solved and the results are compared with those obtained from other methods

A method for solving moving boundary problems in heat flow Part I: Using cubic splines

A new approach to a heat-flow problem involving a moving boundary makes use of a grid system which moves with the boundary. The necessary interpolations are performed by using cubic splines. The method smooths out irregularities in the motion of the boundary which were evident in previous calculations based on a fixed grid system

Barrier modification in sub-barrier fusion reactions using Wong formula with Skyrme forces in semiclassical formalism

We obtain the nuclear proximity potential by using semiclassical extended Thomas Fermi (ETF) approach in Skyrme energy density formalism (SEDF), and use it in the extended $\ell$-summed Wong formula under frozen density approximation. This method has the advantage of allowing the use of different Skyrme forces, giving different barriers. Thus, for a given reaction, we could choose a Skyrme force with proper barrier characteristics, not-requiring extra ``barrier lowering" or ``barrier narrowing" for a best fit to data. For the $^{64}$Ni+$^{100}$Mo reaction, the $\ell$-summed Wong formula, with effects of deformations and orientations of nuclei included, fits the fusion-evaporation cross section data exactly for the force GSkI, requiring additional barrier modifications for forces SIII and SV. However, the same for other similar reactions, like $^{58,64}$Ni+$^{58,64}$Ni, fits the data best for SIII force. Hence, the barrier modification effects in $\ell$-summed Wong expression depends on the choice of Skyrme force in extended ETF method.Comment: INPC2010, Vancouver, CANAD

Fermions obstruct dimensional reduction in hot QCD

We have studied, for the first time, screening masses obtained from glueball-like correlators in Quantum Chromodynamics with four light dynamical flavours of quarks in the temperature range 1.5T_c < T < 3T_c, where T_c is the temperature at which the chiral transition occurs. We have also studied pion-like and sigma-like screening masses, and found that they are degenerate in the entire range of T. These obstruct perturbative dimensional reduction since the lowest glueball screening mass is heavier than them. Extrapolation of our results suggests that this obstruction may affect the entire range of temperature expected to be reached even at the Large Hadron Collider.Comment: 4 pages RevTeX, 2 eps figures included; minor corrections: version for publicatio

A method for solving moving boundary problems in heat flow part ii: Using cubic polynomials

A moving grid system has been used to get the solution of the moving boundary problem discussed earlier in Part I, but basing the necessary interpolations on ordinary cubic polynomials rather than splines. The computations are much more economical and the results obtained are also found to he more satiafactory