Mechanical & Fluid Systems

RFID Cavity

Potential applications include inventory tracking for containers such as waste receptacles or storage containers.This technology provides a method for interrogating collections of items with radio-frequency identification (RFID) tags. It increases the read accuracy, meaning that more of the item tags will be successfully read. It also permits smaller tag antennas than would otherwise be necessary.

Posted in: Briefs, Fluid Handling, Mechanical Components, Mechanics, Downsizing, Antennas, Product development, Radio-frequency identification, Reliability

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Method for Asteroid Volatile Extraction in Space

The method would support human missions to Mars or other distant objects.Some meteorites representative of certain classes of asteroids are 25% or more water by weight. This is consistent with infrared spectra of some asteroids, indicating hydrated minerals are abundant in some varieties of carbonaceous chondrite asteroids. Since water is very valuable in space, it would be desirable to be able to process asteroids to recover this water and other volatiles. The Asteroid Redirect Mission concept has formulated a method for returning asteroids of 1,000-ton mass into the Earth-Moon system orbit using only ~10 tons of propellant. If ~25% of that returned asteroid mass were recovered as volatiles and solar power used to make those volatiles into propellant, then the overall system would generate approximately 25 times as much propellant as it uses. This could be used to make sustainable human missions to Mars or otherwise spread humanity into the solar system.

Posted in: Briefs, Aerospace, Fluid Handling, Mechanical Components, Mechanics, Water reclamation, Life support systems, Booster rocket engines, Solar rocket engines, Spacecraft

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Improving Stirling Engine Performance Through Optimized Piston and Displacer Motion

Stirling engines typically achieve high efficiency, but lack power density. Low power density prevents them from being used in many applications where internal combustion engines are viable competitors, and increases system costs in applications that require Stirling engines. This limits their operating envelope in both terrestrial and space applications. Sinusoidal piston and displacer motion is one of the causes of low power density. Previous work proposed solving this problem by replacing sinusoidal waveforms with waveforms that more closely approximate those of the ideal Stirling cycle. However, when working with real engines, imposing ideal waveforms has been shown to reduce power density and efficiency due to increased pressure drop through the regenerator and heat exchangers.

Posted in: Briefs, Fluid Handling, Mechanical Components, Mechanics, Motors & Drives, Engine efficiency, Pistons, Stirling engines

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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: White Papers, White Papers, Mechanical Components, Mechanics

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Machine Positioning Uncertainty with Laser Interferometer Feedback

Laser interferometers are used as a measurement reference for machine correction and accuracy validation in the production of many high precision motion systems. Under controlled environmental conditions, laser interferometer measurement can provide low measurement uncertainty relative to the achievable accuracy of most commonly used motion control devices. As such, when processes require the utmost precision, laser interferometer measurement near the machine’s work point is frequently used as the feedback mechanism for machine control. In these instances, the use of laser interferometry to characterize the machine’s motion is unjustified because the measurement uncertainty of the metrology system is equivalent or higher than the motion error. The accuracy of these machines’ motion must be equated to an uncertainty in the feedback system’s measurement of the defined work point’s motion.

Posted in: White Papers, Mechanical Components, Mechanics

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Pedal Position Sensing in Heavy-Duty Vehicles

Pedal position detection is nothing new when it comes to operation of heavy duty equipment. However, the age old system operation of mechanical linkages between the pedal and the engine just might be coming to an end. New sensor technology is now enabling non-contact, drive-by-wire that can reduce total system cost while standing up to the harsh environments of off highway equipment.

Posted in: White Papers, Fluid Handling, Mechanical Components, Motion Control, Data Acquisition, Sensors

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How to Make Low Flow Measurements Using Turbine Flow Meters

Accurate low flow measurement represents significant challenges in many applications. Some typical low flow applications in the aerospace market include: small UAV fuel consumption, satellite thruster fuel consumption, and fuel/chemical/water injection. The low dynamic energy associated with flow rates down to 0.001 GPM exceed the capabilities of most mechanical flow meters and force the use of less accurate flow meter technologies.

Posted in: White Papers, Mechanical Components, Data Acquisition, Sensors, Instrumentation

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