Preparation and Characterization of Porous Composite Filter Medium by Polytetrafluoroethylene Foam Coating
Abstract The high costs of ceramic and Teflon filter media for hot gas cleaning has limited their industrial applications. This paper presents a foam coating technology that can be used to produce an inexpensive and highly efficient filter for industrial applications. A new apparatus was designed and built that coats porous glass mats with liquid-phase polytetrafluoroethylene (PTFE). The machine generates bubbles, enables the formation of uniform micropores less than 45 μm in diameter, and produces a product with air permeability greater than 5.5 cm3/cm2/sec. The resulting filter was found to be thermally stable up to 270 °C without any visible distortion and was comparable in dust collection efficiency to other commercial filter media. In addition, its de-dusting efficiency was greater than 85%, which is similar to that of other test filter media.
Removal characteristics of nitrogen oxides and particulates of a novel Mn-Ce-Nb-Ox/P84 catalytic filter applied for cement kiln
Abstract A novel Mn-Ce-Nb-O x /P84 catalytic filter for synergetic removal of particulates and NO was designed and prepared by a new method using functional foaming coating. Removal characteristics of nitrogen oxides (including catalyst loading amount, O 2 concentration, NH 3 /NO molar ratio, H 2 O and SO 2 ) and particulates, were systematically studied. Results showed that the NO removal efficiency of catalytic filter reached 95.3% at 200 °C, as the catalyst loading amount, filtration velocity and mole ratio of NH 3 /NO were set to be 450 g/m 2 , 1 m/min and 1, respectively. The removal characteristic of particulates of Mn-Ce-Nb-O x /P84 catalytic filter belonged surface filtration and the PM2.5 removal efficiency reached 99.98%.
Determining the Jaw Relationship
Contacts between the upper and lower posterior teeth of complete dentures take place during the opening and closing strokes of mastication (Brudvik and Howell 1990). These contacts are fast, gliding impacts of the mandibular teeth which contact close to the position of maximal intercuspation of the teeth, called the “intercuspal occlusion”. The intercuspal position is the position adopted by the mandible when the teeth are in intercuspal occlusion.