Special Coverage

Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research
Small Robot Has Outstanding Vertical Agility
Smart Optical Material Characterization System and Method
Lightweight, Flexible Thermal Protection System for Fire Protection

Floating Ultrasonic Transducer Inspection System for Nondestructive Evaluation

Langley Research Center, Hampton, Virginia This floating ultrasonic transducer inspection system is based on a “momentary touching” scheme wherein the ultrasonic transducer is in contact with the structure being scanned for a relatively short time while performing the measurement. A vibrating element is a fundamental component, allowing the probe to lift up and down quickly over the surface being scanned. The measurement duty cycle would be long enough to acquire the data. Using this configuration reduces the coefficient of friction significantly by more than 95% based on the measurement duty cycle.

Posted in: Briefs, Physical Sciences, Sensors, Inspections, Non-destructive tests


Multiplexer for Multiple Sensors in a Vacuum Chamber

The multiplexer reduces the number of required feedthroughs and ports. John F. Kennedy Space Center, Florida Vacuum chamber testing at large facilities can require hundreds of instruments, necessitating even more feedthroughs. The number of instruments and sensors that can be fed into a vacuum chamber is limited by the number of feedthrough ports dedicated to instrumentation. Thus high-pin-count, mil-spec-style feedthroughs have been developed, but these are all custom-made and also expensive to make and replace. The high-pin-count feedthroughs also make it much harder to troubleshoot individual wires in case of a problem. By using a multiplexer within the vacuum chamber, the number of wires required per instrument can be reduced to much less than one. The multiplication of wires from within a vacuum chamber allows a drastic increase in sensor and instrumentation channel count, while using the same number of sensor ports and feedthroughs within an existing vacuum system.

Posted in: Briefs, TSP, Physical Sciences, Sensors, Sensors and actuators


Miniaturized Schottky Diode Sensors for Hydrogen and Hydrocarbon Detection at High Temperatures

The sensors have application in fuel leak detection, environmental monitoring, fire detection, security monitoring, and engine emission monitoring. John H. Glenn Research Center, Cleveland, Ohio A miniaturized Schottky diode hydrogen and hydrocarbon sensor with the structure of catalytic metal-metal oxide-silicon carbide (SiC) has been developed. The major innovation of this work is the use of the metal oxide, palladium oxide (PdOx), as a barrier layer between the catalytic metal and the SiC in the gas-sensing structure. A major advantage of adding a PdOx barrier layer between the gate metal and the SiC is to prevent and alleviate chemical reactions between the gate metal and the SiC. Without the PdOx barrier layer, the gate metal and the substrate can easily form metal silicides at high temperature, leading to diode structure disruption. The metal oxide barrier layer can be incorporated into a gas-sensing structure by standard deposition techniques in a controlled manner. This oxide naturally forms with Pd in Pd-based gas sensor systems and can disrupt the gas sensor structure when formed in situ in an uncontrolled manner. However, purposely including this oxide in the Schottky barrier structure produces a stable barrier layer that enables a stable and sensitive gas sensor structure.

Posted in: Briefs, Physical Sciences, Sensors, Sensors and actuators, Exhaust emissions, Fire detection


Analog Ceramic Isolated Voltage Sensor

John H. Glenn Research Center, Cleveland, Ohio Galvanic isolated monitoring of voltages for launch vehicle, missiles, and space-deployed systems can be very challenging. Radiation exposure makes use of optics-based sensors difficult, as they can latch-up and become corrupted by the radiation environment; such devices can moreover be thermally challenged. Magnetic transformer-based methods of isolated voltage measurement require shielding to prevent stray magnetic interference from degrading or corrupting the readings; moreover, magnetic-based solutions are unable to measure voltages down to DC levels.

Posted in: Briefs, TSP, Physical Sciences, Sensors, Sensors and actuators, Ceramics, Launch vehicles, Missiles


Flexible and Erectable Magnetic Field Response Sensors

Langley Research Center, Hampton, Virginia The means to make a flexible and/or erectable magnetic field response sensor, a geometrically fixed capacitor mounting frame, a wireless dipstick, and an elastically flexible capacitor support have been developed. Either the capacitor mounting frame or the flexible, erectable magnetic field response sensor can be developed to take measurements in hazardous conditions, or in containers with environmentally harmful contents, such as a gasoline storage tank.

Posted in: Briefs, TSP, Physical Sciences, Sensors, Sensors and actuators


Miniature Amperometric Solid Electrolyte Carbon Dioxide Sensor with Low Detection Limit

This sensor is applicable to fire detection, personal health monitoring, and environmental monitoring. John H. Glenn Research Center, Cleveland, Ohio A miniaturized amperometric electro-chemical (solid electrolyte) carbon dioxide (CO2) sensor using a novel and robust sensor design has been developed and demonstrated. Semiconductor microfabrication techniques were used in the sensor fabrication, and the sensor is fabricated for robust operation in a range of environments. The sensing area is 1.0 × 1.1 mm. The sensor is operated by applying voltage across the electrodes and measuring the resultant current flow at temperatures from 450 to 600 °C. Linear responses were achieved to the CO2 concentrations from 1% to 4%, and to the natural logrithmic concentrations of the CO2 from 0.02% to 1%. This CO2 sensor has the advantage of being simple to batch-fabricate, small in size, low in power consumption, easy to use, and fast with response time.

Posted in: Briefs, Physical Sciences, Sensors, Sensors and actuators, Carbon dioxide


Improved Light Injection and Detection Methods for fNIRS Headgear for Use in Avionics and Astronautics

The benefits of the innovation allow the technique to move out of the controlled laboratory and into clinical and operational environments. John H. Glenn Research Center, Cleveland, Ohio Measuring hemoglobin concentration changes in the brain with functional near infrared spectroscopy (fNIRS) is a promising technique for monitoring cognitive state to optimize human performance during both aviation and space operations. The detection and prevention of performance decrement is also relevant to safety-critical operational tasks such as monitoring for air traffic control, performing surgery, and driving. Advances in optical instrumentation for fNIRS have been conceptualized and integrated into several new headgear prototypes designed for use by operators in the real world.

Posted in: Briefs, TSP, Physical Sciences, Avionics, Test equipment and instrumentation


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