The following issues are considered: the role of hot heel in scrap melting by electric arcs in the furnace freeboard; advantages and disadvantages of furnaces with a single charging and those with a telescoping shell; Specifics of furnace scrap hampering its heating by burners. The possibilities of using different types of burners for scrap heating are analyzed including stationary burners and ...

BACKGROUND The use of composites in dental restoration has been commonly criticized, due to their underwhelming mechanical properties. This problem may be solved partially by preheating. The present research aims to determine the effect of preheating on the mechanical properties of two different classes of composites. MATERIAL AND METHODS A Silorane-based (Silorane) and a Methacrylate-based (...

utilizing natural clay in the traditional production of the grape concentrates in the villages cause the input of large amounts of some metals (solutes) in the product which will be harmful for the consumers. to eliminate the natural clay from this procedure in non-industrial scale, bentonite was selected as an aid-clarifier and examined in treatments under these conditions: two levels of bento...

Gasification is one of the efficient ways to convert the energy embedded in biomass. Understanding of the effect of a few key parameters such as oxygen enrichment and preheating of air on major design parameters is crucial in designing of a biomass gasifier. In the present study, equilibrium modeling is used to predict the performance of a downdraft gasifier. The composition of producer gas and...

We study non-Gaussianity in two distinct models of preheating: instant and tachyonic. In instant preheating non-Gaussianity is sourced by the local terms generated through the coupled perturbations of the two scalar fields. We find that the non-Gaussianity parameter is given by f NL ∼ 2g < O(1), where g is a coupling constant, so that instant preheating is unlikely to be constrained by WMAP or ...

Symmetry restoration processes during the non-equilibrium stage of “preheating” after inflation is studied. It is shown that symmetry restoration is very efficient when the majority of created particles are concentrated at energies much smaller than the temperature T in equilibrium. The strength of symmetry restoration measured in terms of the equivalent temperature can exceed T by many orders ...

We investigate how the hierarchical merging of dark matter halos, the radiative cooling of baryons, and the energy feedback from supernovae and active galactic nuclei or quasars combine to govern the amount and the thermal state of the hot plasma pervading groups and clusters of galaxies. We show that, by itself, supernova preheating of the external gas flowing into clusters falls short of expl...

This article reports the off-design performance analysis of a closed-cycle ocean thermal energy conversion (OTEC) system when a solar thermal collector is integrated as an add-on preheater or superheater. Design-point analysis of a simple OTEC system was numerically conducted to generate a gross power of 100 kW, representing a base OTEC system. In order to improve the power output of the OTEC s...