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Physical Sciences

Briefs : Physical Sciences
Self-Temperature-Compensated Ceramic Strain Gauges

Ceramic static-strain gauges capable of generating mechanical-strain signals much larger than spurious thermal signals have been invented. These gauges are intended for use at temperatures from room temperature to 1,250 °C. Heretofore, external circuits have been used to provide temperature...

Briefs : Physical Sciences
"Set and Hold With Power Off" Cryogenic Actuators

Magnetostrictive actuators that would hold their displacements with power turned off have been proposed for use at temperatures from about 10 to about 77 K. Such "set and hold with power off" actuators are attractive for effecting fine position adjustments in cryogenic scientific instruments,...

Briefs : Physical Sciences
Interferometric System Images Small Vibrating Structures

A commercial scanning imaging white-light interferometer designed for measuring surface profiles of stationary objects has been modified into an interferometric instrument for imaging vibrating microelectromechanical structures. The modified instrument operates in a stroboscopic mode,...

Briefs : Physical Sciences
Two-Photon Microscope Imaging Spectrometer

A two-photon microscope imaging spectrometer has been proposed for use in scanning confocal two-photon microscopy. The proposed instrument would solve a spectrum-overlap that sometimes arises, as explained below.

Briefs : Physical Sciences
Exploiting Ion/Atom Cold Collisions in Atomic Clocks

Recent advances in laser cooling and trapping of neutral atoms in magneto-optic traps (MOTs) would be exploited in ion-trap-based atomic clocks, according to a proposal. Beams of laser-cooled neutral atoms would be used to: (1) put the ions in the required quantum states (e.g., spin-polarize...

Briefs : Physical Sciences
Efficient Ionizer for an Array of Mass Spectrometers

An electron-beam ionizer has been designed to deliver ions to the entrance apertures of nine miniature quadrupole mass spectrometers in an array. A similar electron-beam ionizer could also be designed for an array of more or fewer mass spectrometers. Principal issues that had to be addressed...

Briefs : Physical Sciences
Analyzing Rocket Exhaust by Atomic-Absorption Spectroscopy

A computer-controlled instrumentation system has been developed for use in measuring concentrations of various atomic species in the exhaust gases of a space-shuttle main engine on a test stand. The system is based on established techniques of atomic-absorption spectroscopy (AAS)....

Briefs : Physical Sciences
Adjustable Optics for Spectral Analysis of Rocket Exhaust

The figure presents additional information on the optics of the atomic-absorption-spectroscopy (AAS) system described in the preceding article. The optics include (1) a periscopic optical subsystem for access to a measurement optical axis in a plane different from that of the input and...

Briefs : Physical Sciences
Thickness-Independent Ultrasonic Characterization of Tubes

A technique for ultrasonic characterization of plates has been extended to tubes and curved structures in general. In this technique, as explained in more detail below, one performs measurements that yield a thickness-independent value of local through-the-thickness speed of sound in a...

Briefs : Physical Sciences
Detecting Metal Ions by Voltammetry Using Diamond Electrodes

Experiments have demonstrated the feasibility of detecting multiple species of toxic metal ions and other ions of interest dissolved in water, by means of voltammetry with electrically conductive artificial diamond electrodes. Diamond is attractive as an electrode material because it...

Briefs : Physical Sciences
Small Balloons for Local Aerial Exploration of Mars

A report proposes the use of lightweight balloon-borne instrumentation systems for exploration in the vicinity of a lander on the surface of Mars. Each system would comprise instrumentation with a mass of about 0.2 kg and a balloon with a mass of about 0.8 kg and volume of about 50...

Briefs : Physical Sciences
Apparatus and Technique for Measuring Distance Between Axles

An optoelectronic apparatus and a technique for its operation have been developed to facilitate and accelerate the measurement of distances of the order of tens of feet to within error limits of about ±1/8 in. (about 3 mm). In the original application, the distance to be measured [≈...

Briefs : Photonics/Optics
Cancellation of Laser Noise in an Unequal-Arm Interferometer

A method of processing phase measurements in an unequal-arm laser Michelson interferometer makes it possible to detect phase effects much smaller than the laser phase noise. In the original application for which the method has been proposed, the interferometer, used to detect...

Briefs : Physical Sciences
Rayleigh-Scattering Measurement of Temperature and Velocity

Figure 1 schematically depicts an experimental setup in which Rayleigh scattering from molecules of a flowing gas is used to measure the temperature and one component of the velocity of the gas. The Rayleigh-scattering apparatus in this setup is capable of operation in the harsh...

Briefs : Physical Sciences
Software for Precise Ultrasonic Contact Measurements

The ULTRA SON computer program is designed for use in precise ultrasonic contact scan measurements for nondestructive characterization of materials. This program performs major functions necessary for controlling an ultrasonic apparatus, analyzing the measurement data generated by the...

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