Piezoelectric bimorph-based microvavle for liquid-based micropropulsion
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Engineering topics
Publications and source records attributed to Yang, E..
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This paper presents a leak-tight piezoelectric microvalve, operating at extremely high upstream pressures for microspacecraft applications.
The goal of this research is to develop inchworm motor systems capable of simultaneously providing nanometer resolution, high stiffness, large output force, long travel range, and compactness for ultraprecision positioning applications in space.
Large-stroke micromachined deformable mirror technology can boost the imaging performance of an otherwise non-rigid, lower-quality telescope structure. The proposed deformable mirror concept in this paper combines a microfabricated large-stroke piezoelectric actuator with a reflective membrane transferred in its entirety from a separate wafer.
This paper describes a proof-of-concept inchworm actuator designed to provide nanometer resolution, high stiffness, large output force, long travel range, and compactness for ultraprecision positioning applications in space.
This paper presents a piezoelectric microvalve technology with a high pressure handling capability for micropropulsion applications.
Formation flying and microspacecraft constellation missions pose new propulsion requirements. Formationflying spacecraft, due to the tight positioning and pointing control requirements, may need thrust control within 1- 20 uN to an accuracy of 0.1 uN for LISA and ST-7, for example. Future missions may have extended thrust ranges into the sub - mN range. However, all do require high specific impulses (>500 sec) due to long required thruster firings.
This paper presents a piezoelectric microvalve technology with a high pressure handling capability for micropropulsion applications.
Development of MEMS (Microelectromechanical Systems) micropropulsion at the Jet Propulsion Laboratory (JPL) is reviewed. This includes a vaporizing liquid micro-thruster for microspacecraft attitude control, a micro-ion emgine for microspacecraft primary propulsion or large spacecraft fine attitude control, as well as several valve studies, including a solenoid valve studied in collaboration with Moog Space Products Division, and a piezoelectric micro-valve.
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The same kerogen-like residue from the algal mats and oozes at Laguna Mormona, Baja California, is examined following degradation by saponification, alkaline KMnO4 oxidation, and HBr treatment. For comparison, pyrolytic degradation is performed for the residue and five others, two of which are obtained from algal mats at Baffin Bay, Texas. Major conclusions are that (1) Saponification of a residue specimen from the algal-ooze residue results in minor amounts of components bonded to it as esters; (2) Alkaline KMnO4 oxidation reveals that the same residue consists of a cross-linked aliphatic nucleus with additional components attached to it as esters; (3) the major products from pyrolysis of the residue include phytenes, pristenes, sterenes, and triterpenes; and (4) the HBr treatment yielded only one product, indicating the absence of a large number of ether-linkages readily cleaved by HBr.
Gas-liquid chromatographic milligram preparative separation of steranes and triterpanes from hydrocarbon fraction of Green River oil shale
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