Special Coverage

High Field Superconducting Magnets
Active Response Gravity Offload and Method
Strat-X
Sonar Inspection Robot System
Lightweight Internal Device to Measure Tension in Hollow- Braided Cordage
System, Apparatus, and Method for Pedal Control
Dust Tolerant Connectors
Home

Narrowband Tunable Optical Filter Using Fiber Bragg Gratings

Research at Langley Research Center has developed a special fiber- Bragg grating optical filter for use in aircraft or spaceborne differential absorption lidar (DIAL) systems for measuring water vapor in the atmosphere of the Earth. The filter is an optical fiber containing two Bragg gratings that afford high reflectance in 10-pm-wide wavelength bands at wavelengths of 946.0 and 949.5 nm. The optical fiber would be glued to a piezoelectric ceramic, to which a voltage could be applied to stretch the gratings and thereby adjust their peak-reflection wavelengths to correspond to atmospheric water vapor lines of interest. The concept of multiple Bragg gratings in a single optical fiber tuning such gratings by stretching the fiber is not new. The novelty of this research lies partly in the application of these concepts to make tunable ultra-narrowband filters for the specific water vapor wavelengths in question. Another element of novelty in the proposal lies in the design of the DIAL instrument in which the filters would be used: The design calls for a unique optical receiver that would couple a lidar signal from a telescope to a filter of the type proposed, then using an optical circulator the light would be detected.

Posted in: Briefs, TSP, Physical Sciences

Read More >>

Advanced Hardware and Software for Monitoring Contamination

Sensor readings can be viewed both locally and remotely. An instrumentation system measures the concentrations of three principal contaminants (nonvolatile residue, hydrocarbon vapor, and particle fallout) in real time. The system includes a computer running special-purpose application software that makes it possible to connect the system into a network (which can, in turn, be connected to the Internet) to enable both local and remote display and analysis of its readings. The system was developed for use in a Kennedy Space Center facility that was required to be maintained at a specified high degree of cleanliness for processing a spacecraft payload that was highly sensitive to contamination. The system is also adaptable to monitoring contamination in other facilities and is an example of an emerging generation of sophisticated instrumentation systems that communicate data with other equipment.

Posted in: Briefs, Physical Sciences

Read More >>

Making Hydrogen by Electrolysis of Methanol

The cost is about half that of making hydrogen by electrolysis of water. Scientists at NASA's Jet Propulsion Laboratory are developing apparatuses for electrolysis of methanol to produce pure hydrogen for use at industrial sites, in scientific laboratories, and in fuel cells. The state-of-the-art onsite hydrogen generators now in use are based on electrolysis of water to produce hydrogen, with oxygen as a byproduct that has no commercial value in this context. The developmental methanol electrolyzers consume less than half the electrical energy of water electrolyzers in producing a given amount of hydrogen. Even when the cost of methanol is included, the cost of producing hydrogen by electrolysis of methanol is still only about half that of producing hydrogen by electrolysis of water.

Posted in: Briefs, TSP, Physical Sciences

Read More >>

Aircraft-Mounted Cloud-Water-Content Probe

This relatively simple instrument contains no heater or pump. An aircraft-mounted instrument for high- resolution, in situ measurement of the abundances of liquid water and ice in clouds is undergoing development. This instrument is intended to overcome the dis- advantages of instruments developed previously for the same purpose. The disadvantages include various combinations of complexity, dependence on heaters and/or pumps, insensitivity to ice crystals, or dependence on droplet/crystal size. The present instrument is relatively simple, does not include a heater or a pump, and is expected (when fully developed) to be sensitive to both water droplets and ice crystals of any size.

Posted in: Briefs, TSP, Physical Sciences

Read More >>

Miniature NMR Spectrometers Without Magnets

These spectrometers would be used to characterize ferromagnetic minerals. Miniature, lightweight nuclear-magnetic-resonance (NMR) spectrometers suitable for characterizing ferromagnetic minerals in the field are undergoing development. In previously developed miniature NMR spectrometers, more than half the weight is contributed by permanent magnets. The present developmental miniature NMR spectrometers can be made much lighter because they do not contain permanent magnets: Unlike other NMR spectrometers, they are designed to operate without applied magnetic fields; instead, they exploit the natural magnetic fields of the mineral phases to be studied.

Posted in: Briefs, TSP, Physical Sciences

Read More >>

Software for Electromagnetic Detection of Buried Explosives

Data from a variety of sensors on different survey grids can be used. U-HUNTER (also called “UXOHUNTER”) is a computer program that affords knowledge-based real-time sensor- fusion and display capabilities for detecting buried objects and materials of interest. U-HUNTER is intended especially for inferring the presence of buried unexploded ordnance and explosive waste from the readings of magnetic and electromagnetic sensors like those commonly used in geophysical surveys. U-HUNTER is also potentially adaptable to such other uses as detection of mines, medical imaging and diagnosis, detecting and monitoring buried pipes and cables, environmental monitoring, and geological surveys.

Posted in: Briefs, TSP, Physical Sciences

Read More >>

Aircraft Anti-Icing Systems Utilizing Induced Hydrophobicity

It should be possible to build lightweight, low-power, low-profile anti-icing systems based on this concept. Aircraft anti-icing systems of a proposed type would utilize static electric fields to reduce or eliminate the electrostatic forces that bond ice and water to metal surfaces. These would be lightweight, low-power-consumption, inexpensive systems that would be installed on the surfaces of wings and other critical airfoils. These systems would not intrude significantly into the interiors of airfoils; they would also not protrude from airfoil surfaces and thus would not disturb aerodynamics.

Posted in: Briefs, Physical Sciences

Read More >>

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.