Abstract:
A system and method for automatic analysis of temperature transition data over an area of a sample surface. The system relies on the use of a microfabricated probe, which can be rapidly heated and cooled and has a sharp tip to provide high spatial resolution. The system also has fast x-y-z positioners, data collection, and algorithms that allow automatic analysis of and visualization of temperature transition data.
Abstract:
A method to prevent the catastrophic failure of electrical contacts of silicon piezoresistive transducers located on a silicon wafer at temperatures above 600° C. comprising the steps of using a lead-free glass frit to surround the contacts and bonding the sensor wafer to a glass wafer employing a lead-free glass and utilizing a modified electrostatic bonding technique to join the silicon wafer to the lead-free glass wafer to form a high temperature SOI device.
Abstract:
The present invention relates to a system for detecting aerodynamic instabilities in a jet turbine engine having a pressure transducer mounted in the engine. The pressure transducer, welded to a circuit in signal communication with a controller, is adapted to send measured pressure readings from air in a combustion chamber to the controller. The controller, located in spaced apart relation from the engine, is adapted by software to detect pressure patterns from the pressure signals generated by the transducer that are indicative of a stall or surge. A series of fuel and air valves located with compression and combustion chambers of the engine are in signal communication with the controller. The controller in response to detecting pressure signals indicating a stall or surge is operative to signals in the valves to change the air flow, air angle, fuel flow or speed to reduce the possibility of a stall or surge.
Abstract:
A resonating pressure transducer operable to measure an applied pressure by measuring changes in a resonant frequency is disclosed. The pressure transducer comprises a plurality of diaphragms formed in a wafer of semi-conducting material between two layers, wherein each of the diaphragms is divided into a plurality of electrically isolated sections; a cavity in one of the covering layers opposite a corresponding one of the diaphragms, a first via formed through a selected one of the layers enables application of a potential to selected ones of the diaphragm sections; and a second via formed through a selected one of the layers enables transmission of a measure from selected ones of the diaphragm sections.
Abstract:
A pressure sensing device produces an output proportional to applied pressure irrespective of vibration/acceleration of the device, which device also provides an output proportional only to vibration/acceleration of the device irrespective of the pressure.
Abstract:
A fluid flow probe including: first, second and third pressure sensors; a first port for communicating a first pressure to the first pressure sensor; a second port for communicating a second pressure to the second pressure sensor, the second port being substantially oppositely disposed with respect to the first port, a third pressure port suitable for communicating a static pressure to the third pressure sensor; first and second outputs electrically coupled to the first and second pressure sensors, respectively, one of the first and second outputs indicative of a total pressure and the other of the outputs indicative of a base pressure; and, a third output electrically coupled to the third pressure sensor and indicative of the static pressure.
Abstract:
A pressure transducer assembly including: a pressure sensor header; a transducer assembly member; and a joining arrangement disposed at an interface of the header and the transducer assembly member, for joining the header with the transducer assembly member, the joining arrangement including: a recessed female joining element formed in one of the header and the transducer assembly member; and a protruding male joining element formed on the other of the header and the transducer assembly member, the male joining element received in the female joining element.
Abstract:
An electronic switch of the type uses a piezoresistive Wheatstone bridge configuration to sense pressure. The output of the Wheatstone bridge is applied to an electronic control circuit which contains a comparator. The comparator monitors the output of the bridge and if the output voltage of the bridge exceeds a predetermined value, as indicated by the comparator, a switch is closed to illuminate a lamp indicating to the operator that the pressure has been exceeded. One terminal of a resistor is connected to an output of the bridge. The other terminal of the resistor is coupled to a switch which when operated, causes the resistor to be connected in parallel with one of the arms of the bridge, thereby producing an imbalance of the bridge. This imbalance, due to the shunting of the arm of the bridge by the resistor, causes the electronic control circuit to recognize an excessive pressure, whereby the electronics control circuit generates an output signal which causes the electronic switch to close, thereby illuminating the lamp.
Abstract:
Dynamic IR radiation power control, beam steering and focus adjustment for use in a nanoscale IR spectroscopy system based on an Atomic Force Microscope. During illumination with a beam from an IR source, an AFM probe tip interaction with a sample due to local IR sample absorption is monitored. The power of the illumination at the sample is dynamically decreased to minimize sample overheating in locations/wavelengths where absorption is high and increased in locations/wavelengths where absorption is low to maintain signal to noise. Beam alignment and focus optimization as a function of wavelength are automatically performed.
Abstract:
A pressure header assembly has a closed front and back surface. The back surface has an aperture for accommodating a separate dual die pressure header. The dual die pressure header has an absolute and differential pressure sensor positioned thereon. A differential pressure port is located on a side surface of the pressure header assembly and is directed to a bore in the pressure header assembly. The bore contains an elongated tube which is positioned in the pressure header assembly and locked in place by means of a crush nut and locking nut assembly. One end of the tube is coupled to the differential pressure port, while the other end of the tube accommodates a differential pressure tube which is bent in an arcuate position and directed to the underside of the sensor of the differential sensor assembly mounted in the dual die pressure header. Suitable leads from the dual die pressure header assembly are directed to a terminal board which is mounted within a pressure transducer housing shell, which terminal board coacts with an outboard contact cap assembly forming the transducer. The pressure header assembly portion also contains extending tabs which have apertures for external mounting.