Abstract: Methods and ceramic matrix composite articles formed thereby, as well as systems for making such ceramic matrix composite articles and carrying out such methods are disclosed herein. The methods include preparing a ceramic matrix composite by steps including (a) providing reinforcing fiber, such as carbon fiber, for impregnation; (b) heat treating the reinforcing fiber; (c) impregnating the heat treated reinforcing fiber with a composition comprising a ceramic forming polymer to form a fiber reinforced, ceramic forming polymer pre-preg; and (d) heat molding the fiber reinforced, ceramic forming polymer pre-preg to form a molded ceramic matrix composite article.

Abstract: Sealing assemblies are described herein useful for high temperature applications, as well as applications involving aggressive chemical reactants, byproducts and/or reaction environments. The assemblies include an outer ring having an interior surface having two inwardly extending projections defining a seal receiving area, an inner ring having an exterior surface having two outwardly extending projections defining a seal receiving area; and a center sealing ring configured to be positioned within the seal receiving areas of the outer ring and the inner ring. When the sealing assembly is installed in a high temperature application, the elastomeric center sealing ring is enclosed within the outer and the inner rings so as to protect the center sealing ring while allowing for thermal expansion of the center sealing ring. In further embodiments, bonded sealing ring bodies are disclosed as well.

Abstract: Sealing assemblies are described herein useful for high temperature applications, as well as applications involving aggressive chemical reactants, byproducts and/or reaction environments. The assemblies include an outer ring having an interior surface having two inwardly extending projections defining a seal receiving area, an inner ring having an exterior surface having two outwardly extending projections defining a seal receiving area; and a center sealing ring configured to be positioned within the seal receiving areas of the outer ring and the inner ring. When the sealing assembly is installed in a high temperature application, the elastomeric center sealing ring is enclosed within the outer and the inner rings so as to protect the center sealing ring while allowing for thermal expansion of the center sealing ring. In further embodiments, bonded sealing ring bodies are disclosed as well.

Abstract: A method for forming a ceramic matrix composite bearing includes preparing a layup slurry from a mixture of water, pre-ceramic polymer and refractory filler. The method further includes forming a concentric stack of slurry-impregnated fabric sleeve layers over a rod-shaped inner mold and applying an outer mold to form a mold assembly. The method also includes heating the mold assembly to form a tubular green body and rough cutting the green body to bearing length. In addition, the method includes heat-treating the bearing and performing a polymer infiltration and pyrolysis treatment. The method further includes conducting dimensional stability treatment processes on the bearing and final grinding and machining to meet pre-determined specifications.

Abstract: Sealing assemblies are described herein useful for high temperature applications, as well as applications involving aggressive chemical reactants, byproducts and/or reaction environments. The assemblies include an outer ring having an interior surface having two inwardly extending projections defining a seal receiving area, an inner ring having an exterior surface having two outwardly extending projections defining a seal receiving area; and a center sealing ring configured to be positioned within the seal receiving areas of the outer ring and the inner ring. When the sealing assembly is installed in a high temperature application, the elastomeric center sealing ring is enclosed within the outer and the inner rings so as to protect the center sealing ring while allowing for thermal expansion of the center sealing ring. In further embodiments, bonded sealing ring bodies are disclosed as well.

Abstract: A method of improving performance of a dual Vt integrated circuit is disclosed in which a first value is calculated for each transistor of the integrated circuit that has a first threshold voltage level. The first value is based at least in part on delay and leakage of the circuit calculated as if the corresponding transistor had a second threshold voltage level. One transistor is then selected based on the first values. The threshold voltage of the selected transistor is then set to the second threshold voltage level. The area of at least one transistor within the circuit is modified, and the circuit is then sized to a predetermined area. The process may then be repeated if the circuit performance fails to meet a defined constraint.

Abstract: A slack time, based on a required and actual delay time, is calculated for each node in a circuit (302). For each element in the circuit, a sensitivity (304) and a figure of merit (306) is calculated. A variance is determined for the calculated figure of merits (308). The circuit element having the smallest absolute figure or merit is optimized when the variance is smaller than a predefined threshold (310, 312).

Abstract: A hologram forming system for forming, from a single beam source and a reflective mirror, a reflective hologram in which spurious reflection and transmission hologram recordings are eliminated. Reflected rays are changed in phase relative to the primary beams during the recording period so that spurious holograms do not form. The remaining effect of the reflected rays is to slightly change the overall refractive index of a phase recording material (such as dichromated gelatin) with a resultant slight loss of available index of modulation or to slightly, uniformly, darken an amplitude hologram film, (such as silver halide) with a slight loss of available contrast. The invention includes hologram forming systems that move the cover plate relative to a fixed recording medium with and without a phase shifter in the primary beam and a hologram forming system that moves the substrate and mirror relative to the fixed cover plate.

Abstract: The systems of the invention form improved reflection and transmission holograms utilizing two beams and eliminating all of the higher energy spurious holographic recordings that are caused by reflections of rays from the outer surfaces of the cover plates. The systems provide movement of the cover plate or movement of the substrate and recording medium during the recording period to prevent formation of the spurious recordings. In some arrangements of the invention, global phase shifters are utilized to maintain the phase of the primary rays forming the desired hologram at a high level.

Abstract: The hologram forming systems of the invention form diffusion type holograms in which undesired spurious transmission hologram recordings are eliminated. The reflecting surfaces are moved during the recording process so that the reflected rays change in phase relative to the primary recording beams and spurious holograms cannot be recorded with sufficient intensity to form undesired reflections in the developed hologram. Thus, pictorial type holograms such as jewelry holograms or art holograms do not present undesired ghost images or flare patterns to the viewer. The concepts of the invention also include formation of diffusion type holograms for high gain directional viewing screens.