Abstract: A method of operating a rotating detonation combustor includes providing a flow of air through an air inlet into a detonation chamber, providing fuel from a fuel injector into one of the air inlet or the detonation chamber, mixing the fuel and air to generate a fuel-air mixture, detonating the fuel-air mixture to generate rotating detonation waves, and controlling, during operation of the rotating detonation combustor from a first power operating state to a second power operating state, different from the first power operating state, a flow of an auxiliary gas through an auxiliary gas injection port into one of the air inlet to mix with the flow of the air within the air inlet to control a discharge coefficient of the air inlet, or into the detonation chamber to control a discharge coefficient of the detonation chamber, and to control an operating mode of the rotating detonation combustor.

Abstract: A high-speed, air-breathing propulsion engine includes a rotating detonation combustor configured to burn a fuel-air mixture and at least one ram scoop. The at least one ram scoop is configured to separate incoming air into a core flow stream and a pilot flow stream. The at least one ramp scoop is configured to cause the separation of the core flow stream and the pilot flow stream at a location disposed within a range of locations. The engine is configured to combine the pilot flow stream and the core flow stream in the rotating detonation combustor to enable a rotating detonation wave in the rotating detonation combustor.

Abstract: A method of operating a rotating detonation combustor includes providing a flow of air through an air inlet to flow into a detonation chamber, providing a flow of fuel from at least one fuel injector into the detonation chamber, mixing the flow of the fuel and the flow of the air in the detonation chamber to generate a fuel-air mixture, detonating the fuel-air mixture in the detonation chamber to generate rotating detonation waves within the detonation chamber, and controlling, during operation of the rotating detonation combustor from a first power operating state to a second power operating state, different from the first power operating state, the air inlet wall to control the flow of the air through the air inlet into the detonation chamber to control a discharge coefficient and an operating mode within the detonation chamber.

Abstract: Combustor systems are provided that include rotating detonation combustors (RDCs) arranged in series. In some embodiments, a combustor system includes a volume that receives a core oxidizer-fuel mixture. The combustor system includes a first RDC having a first detonation chamber. The first detonation chamber receives a first pilot oxidizer-fuel mixture and is bounded by a first channel formed in a peripheral wall. The combustor system further includes at least one additional RDC having a second detonation chamber. The second detonation chamber receives a second pilot oxidizer-fuel mixture and is bounded by a second channel formed in the peripheral wall. The first pilot oxidizer-fuel mixture reacts in the first detonation chamber and the second pilot oxidizer-fuel mixture reacts in the second detonation chamber to generate rotating detonation combustion waves that are guided by the first channel and the second channel to support a reaction that consumes the core oxidizer-fuel mixture.

Abstract: Combustor systems are provided that include rotating detonation combustors (RDCs) arranged in series. In some embodiments, a combustor system includes a volume that receives a core oxidizer-fuel mixture. The combustor system includes a first RDC having a first detonation chamber. The first detonation chamber receives a first pilot oxidizer-fuel mixture and is bounded by a first channel formed in a peripheral wall. The combustor system further includes at least one additional RDC having a second detonation chamber. The second detonation chamber receives a second pilot oxidizer-fuel mixture and is bounded by a second channel formed in the peripheral wall. The first pilot oxidizer-fuel mixture reacts in the first detonation chamber and the second pilot oxidizer-fuel mixture reacts in the second detonation chamber to generate rotating detonation combustion waves that are guided by the first channel and the second channel to support a reaction that consumes the core oxidizer-fuel mixture.

Abstract: Systems and methods are provided to implement a database system configured to return the state of a data item upon failure of a condition check on the data item during a conditional write. In embodiments, a write request may specify an indicator to return the item state upon condition failure. The request may specify multiple database operations to execute as a transaction, where failure of a single condition check will cause the entire transaction to fail and an item state causing the failure to be returned. The returned state of the data item may include a selection of the item's attributes specified by the request. Advantageously, these features allow a client to easily obtain the precise cause of a write's failure. Moreover, because the item state is returned only when a conditional write fails and only when requested, the response size of most write requests remains unchanged.

Abstract: This invention relates to a paper substrate containing high surface sizing and low internal sizing and having high dimensional stability, as well as methods of making and using the composition.

Abstract: The present invention relates to a sizing composition that, when applied to paper substrate, creates a substrate, preferably suitable for inkjet printing, having increased print density, print sharpness, low HST, and/or image dry time, the substrate preferably having high brightness and reduced color-to-color bleed as well. In addition, the present invention relates to a method of reducing the HST of a paper substrate by applying the sizing composition to at least one surface thereof. Further, the application relates to methods of making and using the sizing composition, as well as methods of making and using the paper containing the sizing composition.

Abstract: The invention provides an apparatus and method for testing the tendency of a paper to curl. The paper is cut from a paper making machine and rapidly humidified to standard TAPPI conditions, and is thereafter run through an apparatus having a substantially vertically oriented nip. The paper is measured for curl, all data are tabulated and fed back into a data acquisition or paper machine control system.

Abstract: The invention provides an apparatus and method for testing the tendency of a paper to curl. The paper is cut from a paper making machine and rapidly humidified to standard TAPPI conditions, and is thereafter run through an apparatus having a substantially vertically oriented nip. The paper is measured for curl, all data are tabulated and fed back into a data acquisition or paper machine control system.

Abstract: The invention involves papers having either an internal starch or a size press applied starch and a boron-containing compound which is added in proportion to the starch and which is believed to interact with the starch to provide improved physical and mechanical properties in the paper.