The unmatched X-ray resolution of Chandra allows probing the gas flow near quiescent supermassive black holes (BHs). The radius of BH gravitational influence on gas, called the Bondi radius, is resolved in Sgr A* and NGC 3115. Shallow accretion flow density profiles n ∝ r−β with β=0.7–1.0 were found for Sgr A* and NGC 3115 with the help of Chandra. We construct self-consistent models with gas feeding and dynamics from near the Bondi radius to the event horizon to explain the observations. Gas is mainly supplied to the region by hot colliding stellar winds. Small-scale feedback such as conduction effectively flattens the density profile from steep β=1.5 in a Bondi flow. We further constrain density and temperature profiles using the observed radio/sub-mm radiation emitted near the event horizon. We discuss the present state of our numerical model and its qualitative features, such as the role of the galactic gravitational potential and the random motion of wind-emitting stars.

Chandra observations of early-type galaxies have resolved large populations of low-mass X-ray binaries (LMXBs) in early-type galaxies. The majority of these observations have been snapshots on the order of a day or less. In our own Galaxy, LMXBs are known to exhibit a range of luminosity and spectral variability. Multi-epoch observations of early-type galaxies are just beginning to explore the regime of variability on timescales of days to years. We present results for NGC 4365 and NGC 4697, and compare them to the Milky Way.

Ceramic materials in monolithic honeycomb form offer the advantage of low pressure drop for automotive & stationary emissions control reactors, catalytic oxidation, adsorption, separation, and other applications. The ceramic materials can be extruded into cellular monoliths or coated onto a cellular ceramic substrate using conventional “washcoat” processes. Both extruded and coated ceramic substrates are prepared with a binder to promote interparticle adhesion and strength. For many applications it is advantageous to control pore structure, density, strength and surface area.

In this paper composition, fabrication and physical properties of cellular monolithic substrates will be reviewed. Emphasis will be on extruded materials used as catalytic supports for automotive, DeNOx and oxidation reactions.