We explore the relationship between the metallicity of the intracluster gas in clusters of galaxies, determined by X-ray spectroscopy, and the presence of cooling flows. Using ASCA spectra and ROSAT images, we demonstrate a clear segregation between the metallicities of clusters with and without cooling flows. On average, cooling-flow clusters have an emission-weighted metallicity a factor ∼ 1....

Design of a natural dry cooling tower has been accomplished in two sections: the design of heat exchangers and the numerical solution of flow through the tower. Heat exchanger (Heller type) has been simulated thermodynamically and then coupled with a computer program, which calculated the turbulent natural convection flow through the tower. The computer program developed for this purpose can be...

We report the discovery of a z = 2.83 quasar in the field of the cooling flow galaxy cluster Abell 478. This quasar was first detected in a submm survey of star forming galaxies at high redshifts, as the brightest source. We discuss the optical spectrum and far–IR spectral energy distribution (SED) of this object.

The role of thermal conduction in regulating the thermal behavior of cooling flows in galaxy clusters is reexamined. Recent investigations have shown that the anisotropic Coulomb heat flux caused by a magnetic field in a dilute plasma drives a dynamical instability. A long standing problem of cooling flow theory has been to understand how thermal conduction can offset radiative core losses with...

An 8.3 hour observation of the Abell 2256 galaxy cluster using the Rossi X-ray Timing Explorer (RXTE) proportional counter array (PCA) produced a high quality spectrum in the 2 30 keV range. Joint fitting with the 0.7 11 keV spectrum obtained with the Advanced Satellite for Astrophysics and Cosmology (ASCA) Gas Imaging spectrometer (GIS) gives an upperlimit of ∼2.3×10−7 photons cm−2 sec−1 keV−1...

Walker (1973; Phil. Trans. R. Soc. Lond., 274, 107) argued that, for a limited set of compositions and flow types, effusion rate (E) was the principal influence on flow length, sparking a series of studies into the volume and cooling limits on flow extension. We here review these works, as well as the role of heat loss in controlling flow length. We also explore the applicability of Walker’s id...

jet impingement heat transfer is an effective and practical approach that is employed in many industrial processes where heating, cooling, or drying is required. details of the heat or mass transfer rate have been investigated both experimentally and numerically and can be found in the published literature. in most of the numerical studies, control-volume approach has been employed to solve the...

The effects of cooling flow injection on the flow development and acoustic oscillation in a premixed swirl-stabilized combustor had been numerically investigated using 3D large-eddy simulation. Three different cases, including one with no injection and two with cooling flow injection (5, 20 m s), were simulated. With injection of cooling flow-through slits in the combustor wall, the absolute ve...