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Cooling Test Samples With a Combined Convective and Conductive System to Rapidly Reach 77 K

This innovation enables rapid cooling to 77 K of James Webb Space Telescope shields, which enables hypervelocity impact testing with micro-particle spheres. Lyndon B. Johnson Space Center, Houston, Texas In this innovation, a team successfully developed and implemented a combined convective and conductive cooling system that permits rapid cooling. Using a spray system, liquid nitrogen (LN2) was injected into a test article enclosure located in the target tank that was evacuated to a lower pressure than the surrounding ambient pressure of the White Sands Test Facility (WSTF). According to the saturation curve for nitrogen, temperatures lower than 77 K can be achieved by using the evaporative process as long as the pressure remains above the triple point where nitrogen ice is formed.

Posted in: Articles, Briefs, TSP

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White Paper: Alternative Linear Motion Solution

Learn how Nexen’s Roller Pinion System (RPS) delivers a revolutionary alternative to today’s linear motion solutions – with unlimited run length, superior positional accuracy, zero backlash and more.

Posted in: White Papers

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Unique Method for Orifice Production

To produce accurate, repeatable orifices, all the variables that might influence the Cd Value (Coefficient of Discharge) must be controlled during production. This includes the orifice hole length, edges, surface finishes, roundness and the elimination of all tool marks, burrs, ragged edges and irregularities. If any one of these areas is not perfectly managed, the orifice flow rates will vary from piece to piece thereby making it impossible to predict flow with any accuracy.

Posted in: Mechanics, White Papers, White Papers

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Variable-Sweep-Wing Aircraft Configuration

There are significant improvements in structural, aerodynamic, and energy efficiency. Ames Research Center, Moffett Field, California Efficient aircraft designs are increasingly desired in order to support the continued growth of the air transportation industry. Continued expansion of this vital mode of transportation is threatened due to concerns over ever-increasing emissions, noise, and the demand for fuel. Current airport runway, ramp, and terminal facilities are increasingly constrained by encroaching growth and neighborhood environmental issues. The challenges associated with ever-increasing demand for air travel will require the development of aircraft that can fly efficiently over wide speed ranges, minimize their environmental impacts, offer the potential for sizing and growth relative to market demand, and make efficient use of constrained airport and airspace resources.

Posted in: Articles, Briefs, Aviation, Energy Efficiency

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Wire Springs versus Machined Springs A Comparison

The first question generally asked about Machined Springs is how they compare with Wire Wound Springs. Commencing with this question, this review of Machined Springs will proceed. Wire Springs appeared early in the Industrial Revolution. They established their value immediately, and have not wavered from that most useful course. Certainly, enhancements in materials and manufacturing have been forthcoming, but the basic concept has not changed much. Spring wire coiled hot or cold with ends configured within the limits of coil wire has proven to be a very cost effective, industrial tool that exhibits elasticity within the bounds of known, engineering understanding. Uses range from deep ocean applications to man's reach into the universe. Finding a modern day device large or small, that does not benefit from elasticity, and particularly that provided by Wire Wound Springs, is a rare find.

Posted in: White Papers

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Piezo Engineering Tutorial

1.0 The Direct and Inverse Piezoelectric Effect In 1880, while performing experiments with tourmaline, quartz, topaz, cane sugar and Rochelle salt crystals, Pierre and Jacques Curie discovered that when mechanical stress was applied to a crystal, faint electric charges developed on the surface of that crystal. The prefix “piezo” comes from the Greek piezein, which means to squeeze or press. As a result, piezoelectricity is electrical charge that is produced on certain materials when that material is subjected to an applied mechanical stress or pressure. This is known as the direct piezoelectric effect.

Posted in: White Papers

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Reliable Linear Motion For Packaging Machines

In the productivity-driven packaging industry, there are many possible sources of downtime. You can eliminate many of them by selecting failure-resistant linear motion components.

Posted in: White Papers

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