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Noncircular Cross Sections Could Enhance Mixing in Sprays

Preliminary results suggest that elliptical cross sections may be best. A computational study has shown that by injecting drops in jets of gas having square, elliptical, triangular, or other noncircular injection cross sections, it should be possible to increase (relative to comparable situations having circular cross section) the entrainment and dispersion of liquid drops. This finding has practical significance for a variety of applications in which it is desirable to increase dispersion of drops. For example, in chemical-process sprays, increased dispersion leads to increases in chemical-reaction rates; in diesel engines, increasing the dispersion of drops of sprayed fuel reduces the production of soot; and in household and paint sprays, increasing the dispersion of drops makes it possible to cover larger surfaces.

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A Match Made in Space

Just before the space shuttle reaches orbit, its three main engines shut down so that it can achieve separation from the massive external tank that provided the fuel required for liftoff and ascent. In jettisoning the external tank—which is completely devoid of fuel at this point in the flight—the space shuttle fires a series of thrusters, separate from its main engines, that gives the orbiter the maneuvering ability necessary to safely steer clear of the descending tank and maintain its intended flight path. These thrusters make up the space shuttle’s Reaction Control System.

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X-ray Device Makes Scrubbing Rugs Clean a Spotless Effort

If “pulling the rug out from under” means suddenly withdrawing support and assistance, then NASA is pretty good at “putting the rug under” when it comes to offering technical support and assistance to private industry. In the case of a new X-ray fluorescence (XRF) sensor featuring enhancements compliments of NASA, the Space Agency not only provided the rug, but helped give private industry a means to ensure it keeps clean.

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Mirrors Containing Biomimetic Shape-Control Actuators

Local bending would be controlled to obtain desired surface figures. Curved mirrors of a proposed type would comprise lightweight sheets or films containing integral, biologically inspired actuators for controlling their surface figures. These mirrors could be useful in such applications as collection of solar energy, focusing of radio beams, and (provided sufficient precision could be achieved) imaging. These mirrors were originally intended for use in outer space, but it should also be possible to develop terrestrial versions.

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Flight Tests of a Ministick Controller in an F/A-18 Airplane

Pilots' opinions were generally favorable. In March of 1999, five pilots performed flight tests to evaluate the handling qualities of an F/A-18 research airplane equipped with a small-displacement center stick (ministick) controller that had been developed for the JAS 39 Gripen airplane (a fighter/attack/ reconnaissance airplane used by the Swedish air force). For these tests, the ministick was installed in the aft cockpit (see figure) and production support flight control computers (PSFCCs) were used as interfaces between the controller hardware and the standard F/A-18 flight-control laws.

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Piezoelectrically Actuated Shutter for High Vacuum

This vacuum-compatible shutter generates an acceptably small magnetic field. A piezoelectrically actuated shutter is undergoing development for use in experiments on laser cooling of atoms. The shutter is required to be compatible with ultrahigh vacuum [pressure of 10-9 torr (≈1.3 X 10-7 Pa) or less] and to be capable of performing reliably in the vacuum for at least one year. In operation, the shutter would enable the collection and launch of successive samples of cold atoms and would enable the interrogation of the immediately preceding sample while preventing disturbance of the atoms of that sample by light from the collection region.

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Tool for Bending a Metal Tube Precisely in a Confined Space

This tool offers capabilities that prior tools do not. A relatively simple, manually operated tool enables precise bending (typically, within ±1/2° of the specified bend angle) of a metal tube located in a confined space, with a minimum of flattening of the tube and without significant gouging of the tube surface. The tool is designed for use in a situation in which the tube cannot be removed from the confined space for placement in a conventional bench- mounted tube bender. The tool is also designed for use in a situation in which previously available hand-held tube benders do not afford the required precision, do not support the tube wall sufficiently to prevent flattening or gouging, and/or do not fit within the confined space.

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