Tech Briefs

Lightweight, Low-CTE Tubes Made From Biaxially Oriented LCPs

CTEs can be tailored by tailoring biaxial orientations. Tubes made from biaxially oriented liquid-crystal polymers (LCPs) have been developed for use as penetrations on cryogenic tanks. ("Penetrations" in this context denotes feed lines, vent lines, and sensor tubes, all of which contribute to the undesired conduction of heat into the tanks.) In comparison with corresponding prior cryogenic-tank penetrations made from stainless steels and nickel alloys, the LCP penetrations offer advantages of less weight and less thermal conduction. An additional major advantage of LCP components is that one can tailor their coefficients of thermal expansion (CTEs). The estimated cost of continuous production of LCP tubes of typical sizes is about 1.27/ft (4.17/m) [based on 1998 prices].

Posted in: Physical Sciences, Briefs

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Using Redundancy To Reduce Errors in Magnetometer Readings

Fundamental laws of electromagnetism impose constraints that can be exploited. A method of reducing errors in noisy magnetic-field measurements involves exploitation of redundancy in the readings of multiple magnetometers in a cluster. By "redundancy" his meant that the readings are not entirely independent of each other because the relationships among the magnetic-field components that one seeks to measure are governed by the fundamental laws of electromagnetism as expressed by Maxwell ofs equations.

Posted in: Physical Sciences, Briefs, TSP

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Spaceborne Infrared Atmospheric Sounder

A report describes the development of the spaceborne infrared atmospheric sounder (SIRAS)—a spectral imaging instrument, suitable for observing the atmosphere of the Earth from a spacecraft, that utilizes four spectrometers to cover the wavelength range of 12 to 15.4 µm with a spectral resolution that ranges between 1 part per 900 and 1 part per 1,200 in wavelength. The spectrometers are operated in low orders to minimize filtering requirements. Focal planes receive the dispersed energy and provide a spectrum of the scene. The design of the SIRAS combines advanced, wide-field refractive optics with high-dispersion gratings in a solid-state (no moving parts), diffraction-limited optical system that is the smallest such system that can be constructed for the specified wavelength range and resolution. The primary structure of the SIRAS has dimensions of 10 by 10 by 14 cm and has a mass of only 2.03 kg.

Posted in: Physical Sciences, Briefs, TSP

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Method of Calibration for a Large Cathetometer System

This method costs considerably less than does a prior method A method of calibration has been devised for a pair of mutually orthogonal two-axis cathetometers that, when used together, yield measurements of three-dimensional positions of objects mounted on an optical bench. Each cathetometer has a horizontal travel of 1.8 m and a vertical travel of 1.2 m. The cathetometers are required to measure X ,Y, and Z coordinates (see figure) to within ±0.005 in.(±0.127 mm).

Posted in: Mechanical Components, Briefs, TSP

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Advanced Infant Car Seat Would Increase Highway Safety

This system would keep a baby safe, comfortable, and entertained, thereby reducing distractions for an adult driver. An advanced infant car seat has been proposed to increase highway safety by reducing the incidence of crying, fussy behavior, and other child-related distractions that divert an adult driver's attention from driving. In addition to a conventional infant car seat with safety restraints, the proposed advanced infant car seat would include a number of components and subsystems that would function together as a comprehensive infant-care system that would keep its occupant safe, comfortable, and entertained, and would enable the driver to monitor the baby without having to either stop the car or turn around to face the infant during driving.

Posted in: Mechanical Components, Briefs

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New Material for Surface-Enhanced Raman Spectroscopy

Reproducible measurements can be made quickly,without preparation of samples. A chemical method of synthesis and application of coating materials that are especially suitable for surface-enhanced Raman spectroscopy (SERS)has been developed.The purpose of this development is to facilitate the utilization of the inherently high sensitivity of SERS to detect chemicals of interest (analytes) in trace amounts, without need for lengthy sample preparation.

Posted in: Materials, Briefs

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Treated Carbon Nanofibers for Storing Energy in Aqueous KOH

Treatment can increase specific capacitance by as much as 400 percent. A surface treatment has been found to enhance the performances of carbon nanofibers as electrode materials for electrochemical capacitors in which aqueous solutions of potassium hydroxide are used as the electrolytes. In the treatment, sulfonic acid groups are attached to edge plane sites on carbon atoms.

Posted in: Materials, Briefs

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