Abstract: Various methods and systems are provided for calibrating one or more exhaust valves. In one example, a system comprises an exhaust valve configured to control flow of exhaust gas exiting an engine and a controller configured to calibrate the exhaust valve by commanding the exhaust valve to a fully closed position with a first driving current and measuring a first position of the exhaust valve at the first driving current, commanding the exhaust valve to a fully open position with a second driving current and measuring a second position of the exhaust valve at the second driving current, and generating a map based on a linear function determined from the first driving current, the second driving current, the measured first position, and the measured second position. The controller is further configured to adjust a position of the exhaust valve based on the map.

Abstract: Various methods and systems are provided for estimating fresh intake air flow. In one example, a system comprises an engine having an intake manifold to receive fresh intake air and an exhaust gas recirculation (EGR) system to supply EGR to the intake manifold, where flow of EGR through the EGR system is controlled by one or more exhaust valves. The system further includes a controller configured to adjust a position of the one or more exhaust valves based on an estimated fresh intake air flow rate, where during a first set of operating conditions, the fresh intake air flow rate is estimated based on a total gas flow rate into the engine and further based on a current position of the one or more exhaust valves, intake manifold pressure, air-fuel ratio, and fuel flow to one or more cylinders of the engine.

Abstract: Various methods and systems are provided for controlling exhaust gas recirculation in an engine. One embodiment for a system comprises an engine having first and second cylinder groups, and an exhaust gas recirculation (EGR) passage coupled between the first cylinder group and an intake manifold of the engine, flow of EGR through the EGR passage controlled by one or more EGR exhaust valves, and a controller configured to maintain a target intake gas concentration by adjusting the one or more EGR exhaust valves and adjusting fuel injection amounts to the first cylinder group differently than the second cylinder group.

Abstract: The present invention provides a dual-cure composition containing multifunctional polyols, uretidiones, peroxide curable monomers containing unsaturation and crosslinking agents. The dual-cure composition may be used to form a high modulus material useful as the matrix in a prepreg material and in composites. The present invention also relates to methods for the production of the dual-cure composition, prepreg materials comprising the dual-cure composition and a fibrous support, and composites made from the prepreg material.

Abstract: The present invention provides a dual-cure composition containing multifunctional polyols, uretidiones, peroxide curable monomers containing unsaturation and crosslinking agents. The dual-cure composition may be used to form a high modulus material useful as the matrix in a prepreg material and in composites. The present invention also relates to methods for the production of the dual-cure composition, prepreg materials comprising the dual-cure composition and a fibrous support, and composites made from the prepreg material.

Abstract: A composition that includes isocyanate group containing compounds that include on average i) a NCO functionality less than or equal to 3.5; and ii) from 1.5 to 8 percent by weight, based on the isocyanate containing compound, of allophanate groups; and which is substantially free of uretdione groups. The composition can be used in two component elastomeric coating compositions that include a component A the above-described composition and a component B that includes a compound containing one or more functional groups that are reactive with isocyanate groups. The elastomeric coating compositions can be used to coat substrates.

Abstract: A Joint Combined Aircrew Systems Tester (JCAST) that can be used to test aircrew integrated life support equipment currently authorized for use by aircrew members of the Air Force, Navy and Army. The JCAST will be capable of Chemical/Biological seal testing of all the Joint Service Aircrew Mask (JSAM) variants including the Type 2 JSAM for high performance aircraft. Like traditional Testers, the JCAST is capable of Performance and Fit Testing of masks at pressure levels, including COMBAT EDGE (Combined Advanced Technology Enhanced Design “G” Ensemble), consistent with aircraft supply levels. The JCAST provides an apparatus and technique for accurately measuring a leak rate for an elastic body such as a chemical mask at 0.5 sccm at 6 IWG. The JCAST is portable and light weight while providing novel leak testing using pressure decay.

Abstract: A composition that includes isocyanate group containing compounds that include on average i) a NCO functionality less than or equal to 3.5; and ii) from 1.5 to 8 percent by weight, based on the isocyanate containing compound, of allophanate groups; and which is substantially free of uretdione groups. The composition can be used in two component elastomeric coating compositions that include a component A the above-described composition and a component B that includes a compound containing one or more functional groups that are reactive with isocyanate groups. The elastomeric coating compositions can be used to coat substrates.

Abstract: A composition that includes a mixture of A) a prepolymer of aliphatic isocyanates adducted with an active hydrogen functional compound containing a polar group; and B) a polyol containing at least four active hydrogen groups. The mixture does not separate into two phases after standing at room temperature for two hours. The composition can be used to coat a substrate by applying the above described composition to at least a portion of a surface of the substrate.