Engineering Papers⌕ Search

Engineering topics

Liu, F.

Publications and source records attributed to Liu, F..

13 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

The ISS as a Testbed for Future Large Astronomical Observatories: The OpTIIX Demonstration Program

Future large (diameters in excess of approx. 10 m) astronomical observatories in space will need to employ advanced technologies if they are to be affordable. Many of these technologies are ready to be validated on orbit and the International Space Station (ISS) provides a suitable platform for such demonstrations. These technologies include low-cost, low-density, highly deformable mirror segments, coupled with advanced sensing and control methods. In addition, the ISS offers available telerobotic assembly techniques to build an optical testbed that embodies this new cost-effective approach to assemble and achieve diffraction-limited optical performance for very large space telescopes. Given the importance that NASA attaches to the recommendations of the National Academy of Sciences "Decadal Survey" process, essential capabilities and technologies will be demonstrated well in advance of the next Survey, which commences in 2019. To achieve this objective, the Jet Propulsion Laboratory (JPL), NASA Johnson Space Center (JSC), NASA Goddard Space Flight Center (GSFC), and the Space Telescope Science Institute (STScI) are carrying out a Phase A/B study of the Optical Testbed and Integration on ISS eXperiment (OpTIIX). The overarching goal is to demonstrate well before the end of this decade key capabilities intended to enable very large optical systems in the decade of the 2020s. Such a demonstration will retire technical risk in the assembly, alignment, calibration, and operation of future space observatories. The OpTIIX system, as currently designed, is a six-hexagon element, segmented visual-wavelength telescope with an edge-to-edge aperture of 1.4 m, operating at its diffraction limit,

Burdick, G.↗
NASA NTRS2002

The Low Temperature Microgravity Physics Facility

The Low Temperature Microgravity Physics Facility currently in the design phase is a multiple user and multiple flight facility intended to provide a long duration low temperature environment onboard the International Space Station.

microgravity physics facility↗
NASA NTRS2002

Integrate test and qualify NASA facility class payloads on the ISS JEM-EF

This paper describes the processes that the Low Temperature Microgravity PhysicsFacility (LTMPF) follows or will follow to meet the qualification requirements imposed by the Jet Propulsion Laboratory (JPL), by the Microgravity Research Program Office (MRPO) at MSFC, by the ISS Payloads Office (OZ) at JSC, and by NASDA's JEM Element Integration Office.

ISS payloads LTMPF JEM-EF↗
NASA NTRS2000

Differential assembly of alpha- and gamma-filagenins into thick filaments in Caenorhabditis elegans

Muscle thick filaments are highly organized supramolecular assemblies of myosin and associated proteins with lengths, diameters and flexural rigidities characteristic of their source. The cores of body wall muscle thick filaments of the nematode Caenorhabditis elegans are tubular structures of paramyosin sub-filaments coupled by filagenins and have been proposed to serve as templates for the assembly of native thick filaments. We have characterized alpha- and gamma-filagenins, two novel proteins of the cores with calculated molecular masses of 30,043 and 19,601 and isoelectric points of 10.52 and 11.49, respectively. Western blot and immunoelectron microscopy using affinity-purified antibodies confirmed that the two proteins are core components. Immunoelectron microscopy of the cores revealed that they assemble with different periodicities. Immunofluorescence microscopy showed that alpha-filagenin is localized in the medial regions of the A-bands of body wall muscle cells whereas gamma-filagenin is localized in the flanking regions, and that alpha-filagenin is expressed in 1.5-twofold embryos while gamma-filagenin becomes detectable only in late vermiform embryos. The expression of both proteins continues throughout later stages of development. C. elegans body wall muscle thick filaments of these developmental stages have distinct lengths. Our results suggest that the differential assembly of alpha- and gamma-filagenins into thick filaments of distinct lengths may be developmentally regulated.

NASA Discipline Musculoskeletal↗
NASA NTRS1999

Low Temperature Microgravity Physics Facility

The Low Temperature Microgravity Physics Facility (LTMPF) is a state-of-the-art facility for long duration science investigations whose objectives can only be achieved in microgravity and atlow temperature.

microgravity↗
NASA NTRS1985

Fabrication of ceramic components for advanced gas turbine engines

The AGT101 ceramic gas turbine engine feasibility study has made use of the slip casting of silicon or silicon nitride powders to produce either reaction-bonded or sintered components such as turbine rotors, turbine shrouds, and inner and outer diffusers. Attention is given to the effects of processing parameters on the microstructure and properties of the finished components; the parameters encompass powder particle size distribution, casting slip viscosity, pH, and solid content fraction. The green slip cast components were consolidated by nitriding, sintering, or sinter/HIPping.

Liu, F.↗