Physical Sciences

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...

Briefs : Physical Sciences
AlGaN Photodiodes Respond to Ultraviolet C

Solar-blind photodetectors respond only to ultraviolet light at wavelengths shorter than those of the solar radiation that can penetrate atmosphere of the Earth. This wavelength range, traditionally defined as wavelengths

Briefs : Physical Sciences
Parallel 3D EMPIC Algorithm Using Nonorthogonal Grids

Electromagnetic particle-in-cell (EMPIC) codes provide a capability for numerically simulating the motions of electrically charged particles in electromagnetic fields, and hence have become standard software tools in plasma physics research. Most existing EMPIC codes are based on the use of...

Briefs : Physical Sciences
Techniques for Controlling Buoyancy of Balloons on Titan

A report discusses alternative techniques for controlling the buoyancy, and thus the altitude and landings, of a balloon-borne instrumentation system that would be launched to explore the moon Titan of the planet Saturn. Some of the techniques are based on established concepts of heating...

Briefs : Physical Sciences
Lightweight, Low-Power, Inexpensive Ozone Dosimeters

Lightweight, low-power-consumption, inexpensive ozone sensors based on colorimetric chemical sensing would be developed, according to a proposal. Colorimetric chemical sensing is an established technique, but it has not been applied previously to sensing of ozone. The proposed ozone sensors...