Abstract: Disclosed is a filter medium useful for flue gas filtering that comprises a non-woven fibrous web having at least 80 weight percent of meta-aramid fibers and from 0.1 to 20 weight percent of meta-aramid fibrids, based on weight of fibers and fibrids. The non-woven fibrous web can have average pore size of 20 to 80 micrometers, maximum pore size of 100 micrometers, dry Mullen burst strength of at least 7 kg/cm2, retention of 80% of the dry Mullen burst strength after acid cycling, a filtration efficiency of at least 95% for 2.5 micron particle, and/or a shrinkage of less than 2% after being heated in a dry oven at 205 ° C. for 2 hours. A method of making the filter medium comprises wet-laying a furnish of the meta-aramid fibers and the meta-aramid fibrids; drying to form the non-woven fibrous web; preferably, calendering; and optionally saturating with binder resin and curing.

Abstract: An air intake system suitable for a supersonic vehicle is disclosed. The system includes a channel comprising an inlet and a side wall and a plenum coupled to the side wall. The plenum is configured to accept a flow of coolant. In certain embodiments, the coolant is the waste coolant from an on-board electronics cooling system. The system also includes a porous region in the side wall configured to allow a flow of bleed air from the channel through the porous region of the side wall into the plenum so as to aid the transition to supersonic flow. In certain embodiments, the flow of the bleed air is reduced at supersonic speeds by pressurization of the plenum with the coolant.

Abstract: An air intake system suitable for a supersonic vehicle is disclosed. The system includes a channel comprising an inlet and a side wall and a plenum coupled to the side wall. The plenum is configured to accept a flow of coolant. In certain embodiments, the coolant is the waste coolant from an on-board electronics cooling system. The system also includes a porous region in the side wall configured to allow a flow of bleed air from the channel through the porous region of the side wall into the plenum so as to aid the transition to supersonic flow. In certain embodiments, the flow of the bleed air is reduced at supersonic speeds by pressurization of the plenum with the coolant.