Employing XMM-Newton EPIC data we perform a detailed comparison between different spectral models to test whether the gas in cooling-flows is multi-phase or not. Our findings all point in the same direction, namely that gas in cooling-flows does not show the wide distribution of temperatures expected from standard multi-phase models. This result has profound implications for cooling-flow models...

We discuss a numerical 3D radiation-MHD simulation of penumbral fine structure in a small sunspot. This simulation shows the development of short filamentary structures with horizontal flows, similar to observed Evershed flows, and an inward propagation of these structures at a speed compatible with observations. Although the lengths of these filaments are much shorter than observed, we conject...

A comparative numerical study is employed to investigate the heat and mass transfer between air and falling film desiccant in parallel and counter flow configurations. Nanoparticles suspensions are added to the falling film desiccant to study heat and mass transfer enhancements. The numerical results show that the parallel flow channel provides better dehumidification and cooling processes of t...

In this paper we present an X-ray image deprojection analysis of EINSTEIN OBSERVATORY imaging data on 207 clusters of galaxies. The resulting radial profiles for luminosity, temperature , and electron density variations are determined from the cluster surface-brightness profiles according to gravitational potential constraints from average X-ray temperatures and optical velocity dispersions. Th...

1 Abstract The existence of cooling flows in the center of galaxy clusters has always been a puzzle, and in particular the fate of the cooling gas, since the presence of cold gas has never been proven directly. X-ray data from the satellites Chandra and XMM-Newton have constrained the amount of cooling, and it was realized that feedback and heating from a central AGN and its jets could reduce t...

Turbine Inlet Temperatures of 1500-2000K have become a sort of standard for most modern advanced applications. First-stage blades are obviously the most exposed components to such hot gases, and thus they need proper cooling. In the preliminary design of the blades and their cooling system, designers must rely on simple models that can be further refined at a later stage, in order to have an ap...

This paper discusses some notes on the vibration design for the piezoelectric cooling fan. After reviewing the fundamental formulas of the cantilever Euler beam, it is not easy to find the optimal design of the piezoelectric fan. The experiments also show the complicated results of the vibration behavior and air flow. Keywords—Piezoelectric cooling fan, vibration, cantilever Euler beam, air flow.

Air-Conditioning (AC) systems are responsible for a considerable portion of the energy consumption in buildings located in high cooling load requiring regions of Iran. In addition, the heat flow through the buildingschr('39') external walls plays a major role in cooling load estimations for the countrychr('39')s hot regions. Therefore, application of insulation materials in external walls has g...