Aluminum alloys are considered a lot in the automotive and aerospace industry because of their high strength to weight ratio. In this manuscript, the gas forming process of aluminum AA6063 tubes at high temperatures up to 500°C is investigated, through experimental and numerical tests. Therefore, an experimental setup is prepared and so, tube specimens are formed in a die with square cross sect...

in this paper the changes in the heat capacity of cooling towers has been investigated as a result of injecting combustion products of boilers. in the tower, the air is re-heated through mixing with hot flue gas after passing through the heat exchangers. as a result of this process, the draft of the cooling tower is increased. the additional produced draft depends on the ambient temperature and...

It is widely believed that the global baryon content and mass-to-light ratio of groups and clusters of galaxies are a fair representative of the matter mix of the universe and therefore, can be used to reliably determine the cosmic mass density parameter ΩM. However, this fundamental assumption is challenged by growing evidence from optical and X-ray observations that the average gas mass fract...

We discuss two themes from Chandra cluster observations. First, we describe the interaction of buoyant, radio emitting plasma bubbles with the hot intracluster gas. Second we summarize the Chandra observations of "cold" fronts (sharp discontinuities in gas density and temperature) separating cool, denser gas clouds from the hotter intracluster medium. 1. The Radio — X-ray Interaction or Bubbles...

We study the chemodynamical evolution of elliptical galaxies and their X-ray and optical properties using high-resolution cosmological simulations. Our Tree Nbody/SPH code includes a self-consistent treatment of radiative cooling, star formation, supernovae feedback, and chemical enrichment. We present a series of ΛCDM cosmological simulations which trace the spatial and temporal evolution of a...

We present spatially resolved near-IR spectroscopic observations of 15 young stars. Using a grism spectrometer behind the Keck interferometer, we obtained an angular resolution of a few milliarcseconds and a spectral resolution of 230, enabling probes of both gas and dust in the inner disks surrounding the target stars. We find that the angular size of the near-IR emission typically increases w...

Recent data have radically altered the X-ray perspective on cooling flow clusters. X-ray spectra show that very little of the hot intracluster medium is cooler than about 1 keV, despite having short cooling times. In an increasing number of cooling flow clusters, the lobes of a central radio source are found to have created cavities in the hot gas. Generally, the cavities are not overpressured ...

The centers of elliptical galaxies host supermassive black holes that significantly affect the surrounding interstellar medium through feedback resulting from the accretion process. The evolution of this gas and of the nuclear emission during the galaxies’ lifetime has been studied recently with high-resolution hydrodynamical simulations. These included gas cooling and heating specific for an a...

Sgr A is currently being fed by winds from a cluster of gravitationally bound young mass-loosing stars. Using observational constraints on the orbits, mass loss rates and wind velocities of these stars, we numerically model the distribution of gas in the ∼ 0.1–10 region around Sgr A. We find that radiative cooling of recently discovered slow winds leads to the formation of many cool filaments a...