Abstract: An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. The apparatus controls the actuator in response to the sensor. The apparatus prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.

Abstract: According to some embodiments, a first layer of doped material may be provided to form a resistor. A second layer of undoped material may then be formed on the first layer. The first layer might comprise, for example, a layer of doped silicon carbide while the second layer comprises a layer of undoped silicon carbide. The resistance of the resistor may then be measured to determine a temperature.

Abstract: An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. Lastly, the apparatus includes means for controlling the actuator in response to the sensor. The means for controlling prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.

Abstract: A piezoelectric actuator and a method of assembling and employing a piezoelectric actuator. This method comprises the steps of positioning an expandable piezoelectric material inside a case, and enclosing a vaporizable liquid in the case. The case is positioned in a high temperature environment; and the liquid vaporizes, in that high temperature environment, over a given period of time, to maintain the temperature of the piezoelectric material below a given value for said period of time. Preferably, the vaporizing liquid maintains the temperature of the piezoelectric material substantially constant over that period of time. Also, preferably the case is provided with a pressure responsive valve that opens and closes, in the high temperature environment, to expose the liquid to that environment and control the vaporization of the liquid to maintain the temperature of the piezoelectric material substantially constant over the period of time.

Abstract: A microvalve and a method of forming a microvalve. The microvalve comprises first and second layers, a diaphragm member and a switching means. The first and second layers are secured together to form a valve body that forms an inlet opening for receiving fluid, an outlet opening for conducting fluid from the valve body, and a flow channel for conducting fluid from the inlet to the outlet. The diaphragm is disposed between the layers, and is movable between open and closed positions. In these position, the diaphragm, respectively, allows and blocks the flow of fluid from the inlet to the flow channel. The diaphragm is biased to the closed position, and moves from the closed position to the open position when the pressure of fluid in the inlet reaches a preset value. The switching means is connected to the valve body for moving the diaphragm to the closed position against the pressure of fluid in the inlet.

Abstract: A microvalve and a method of forming a microvalve. The microvalve comprises first and second layers, a diaphragm member and a switching means. The first and second layers are secured together to form a valve body that forms an inlet opening for receiving fluid, an outlet opening for conducting fluid from the valve body, and a flow channel for conducting fluid from the inlet to the outlet. The diaphragm is disposed between the layers, and is movable between open and closed positions. In these position, the diaphragm, respectively, allows and blocks the flow of fluid from the inlet to the flow channel. The diaphragm is biased to the closed position, and moves from the closed position to the open position when the pressure of fluid in the inlet reaches a preset value. The switching means is connected to the valve body for moving the diaphragm to the closed position against the pressure of fluid in the inlet.

Abstract: A method for creating deep features in a Si-containing substrate for use in fabricating MEMS type devices is provided. The method includes first forming a thin Ni hardmask on a surface of a Si-containing substrate. The Ni hardmask is patterned using conventional photolithography and wet etching so as to expose at least one portion of the underlying Si-containing substrate. The at least one exposed portion of the Si-containing substrate, not containing the patterned hardmask, is then etched in a plasma that includes free radicals generated from a gaseous mixture of chlorine (Cl2), sulfur hexafluoride (SF6) and oxygen (O2). The interaction of the gas species in the plasma yields a rapid silicon etch rate that is highly selective to the Ni hardmask. The etch rate ratio of Si to Ni using the inventive method is greater than 250:1.

Abstract: A piezoelectric actuator and a method of assembling and employing a piezoelectric actuator. This method comprises the steps of positioning an expandable piezoelectric material inside a case, and enclosing a vaporizable liquid in the case. The case is positioned in a high temperature environment; and the liquid vaporizes, in that high temperature environment, over a given period of time, to maintain the temperature of the piezoelectric material below a given value for said period of time. Preferably, the vaporizing liquid maintains the temperature of the piezoelectric material substantially constant over that period of time. Also, preferably the case is provided with a pressure responsive valve that opens and closes, in the high temperature environment, to expose the liquid to that environment and control the vaporization of the liquid to maintain the temperature of the piezoelectric material substantially constant over the period of time.

Abstract: These and other objectives are attained with a piezoelectric actuator operable over a temperature range, and a method of operating a piezoelectric actuator. The piezoelectric actuator, generally, comprises a support structure, a piezoelectric material supported by the support structuer, and an insert disposed between the support structure and the piezoelectric material. The piezoelectric material and the insert are positioned in series, the piezoelectric material and the insert each have a respective length, and together the piezoelectric material and the insert have a combined length. The length of the piezoelectric material changes in response to a voltage applied to the piezoelectric material. Also, the respective lengths of the piezoelectric material and the insert change, in opposite directions, in response to the same change in temperature, and, in this way, the insert mitigates changes in the combined length of the insert and the piezoelectric material due to temperature changes.

Abstract: A method for creating deep features in a Si-containing substrate for use in fabricating MEMS type devices is provided. The method includes first forming a thin Ni hardmask on a surface of a Si-containing substrate. The Ni hardmask is patterned using conventional photolithography and wet etching so as to expose at least one portion of the underlying Si-containing substrate. The at least one exposed portion of the Si-containing substrate, not containing the patterned hardmask, is then etched in a plasma that includes free radicals generated from a gaseous mixture of chlorine (Cl2), sulfur hexafluoride (SF6) and oxygen (O2). The interaction of the gas species in the plasma yields a rapid silicon etch rate that is highly selective to the Ni hardmask. The etch rate ratio of Si to Ni using the inventive method is greater than 250:1.