The conventional weak-coupling expansion for thermodynamic quantities in hot field theories shows poor convergence unless the coupling constant is tiny. I discuss screened perturbation theory (SPT) which is a way of reorganizing the perturbative expansion for scalar theories and hard-thermal-loop perturbation theory (HTLPT), which is its generalization to gauge theories. I present results for t...

We calculate the cross-section for the thermal n + p! d+ process in chiral perturbation theory to next-to-next-to-leading order using heavy-fermion formalism. The exchange current correction is found to be (4:5 0:3) % in amplitude and the chiral perturbation at one-loop order gives the cross section np th = (334 2) mb which is in agreement with the experimental value (334:2 0:5) mb. Together wi...

A quasi-one-dimensional numerical mode1 containing a prognostic turbulent kinetic energy parameterization and simplified approximations to horizontal gradients is used to study interactions of thermally induced nocturnal slope flows with following and opposing ambient winds. It is found that a following ambient wind causes the peak perturbation wind to be weaker and to be realized at a greater ...

In this paper we discuss the effect of chemical reaction and thermal radiation on unsteady free convective heat and mass transfer flow through a porous medium in a vertical wavy channel. The unsteadiness in the flow is due to the oscillatory flux in the flow region. The coupled equations governing the flow, heat and mass transfer have been solved by using a perturbation technique with the slope...

The spin polarization of Sb overlayers on the semi-Heusler alloy NiMnSb is investigated in terms of the Landau-Ginzburg approach. The half-metallic semi-Heusler alloy NiMnSb acts as a ferromagnetic perturbation and induces a spin polarization in the semimetallic Sb overlayer. Using a Gaussian approximation, the propagation of the spin perturbation in the overlayer is calculated. The results are...