Expulsion bladder-equipped storage tank structure Patent

Expulsion bladder equipped storage tank structur

The linear boom actuator designed for the Galileo spacecraft

Because the linear boom actuator is to be used on a flight spacecraft, as opposed to a ground based application, there is a comprehensive set of requirements. First, of course, the actuator must be capable of positioning and holding the load. Initially the load as predicted to be 4448 N (1000 lb) but with subsequent spacecraft configuration changes the load has been greatly reduced to a constant tensile pull of 1477 N (332 lb) due to centrifugal force. Lesser compressive loads of 1317 N (296 centrifugal lb) may be experienced during launch and deployment. This actuator must have the maximum redundancy possible. Life requirements were defined by the 10.16 to 15.24 cm (4 to 6 in.) total liner travel expected during the five-year flight duration. Liner range required of the actuator was set at plus and minus 5.08 cm to accommodate configuration changes

Remotely operated gas-pressure regulator and shuttle valve

Valve features precise gas-pressure regulation and shuts off flow by remote control. Valve is made up of regulator valve cavity and spring-compression adjusts cavity. Elements in regulator cavity are conventional and include high-pressure inlet, ball which mates with seat, push rod, and pressure-sensing diaphragm

Combined pressure regulator and shutoff valve

A remotely operable pressure regulator and shutoff valve particularly suited for achieving high resolution and flow control, and positive shutoff is described. The valve is characterized by a spring-loaded ball coaxially aligned with a fluid port to be sealed, a spring-loaded pintle extended through the port into engagement with the ball, for controlling the position, a spring-loaded diaphragm for controlling the position of the pintle, and an axially displaceable spring supported by a movable stop which, in turn, is repositioned by a selectively operable stepper motor. Thus, the pressure-response characteristics for the valve can be varied through a selective repositioning of the stop

R-process and alpha-elements in the Galactic disk: Kinematic correlations

Recent studies of elemental abundances in the Galactic halo and in the Galactic disk have underscored the possibility to kinematically separate different Galactic subcomponents. Correlations between the galactocentric rotation velocity and various element ratios were found, providing an important means to link different tracers of star formation and metal enrichment to the Galactic components of different origin (collapse vs. accretion). In the present work we determine stellar kinematics for a sample of 124 disk stars, which we derive from their orbits based on radial velocities and proper motions from the the literature. Our stars form a subsample of the Edvardsson et al. (1993) sample and we concentrate on three main tracers: (i) Europium as an r-process element is predominantly produced in Supernovae of type II. (ii) Likewise, alpha-elements, such as Ca, Si, Mg, are synthesised in SNe II, contrary to iron, which is being produced preferentially in SNe Ia. (iii) The s-process element Barium is a measure of the relative contribution of AGB stars to the Galaxy's enrichment history and has been shown to be an indicator for distinguishing between thin and thick disk stars. All such studies reveal, basically, that stars with low galactocentric rotational velocity tend to have high abundances of alpha-elements and Eu, but lower abundances of, e.g., Ba.Comment: 5 pages, 2 figures, Poster contribution to appear in "Planets To Cosmology: Essential Science In Hubble's Final Years", proceedings of the May 2004 STScI Symposium, M. Livio (ed.), (Cambridge University Press

Remotely operated gripper provides vertical control rod movement

Remote actuation of a gripper shaft affects vertical engagement between a drive shaft and control rod. A secondary function of the gripper is to provide remote indication of positive completion of the gripping or ungripping operation

The Propagation of Quarks in the Spatial Direction in Hot QCD

The dynamics of {\it light} fermions propagating in a spatial direction at high temperatures can be described effectively by a two--dimensional Schr\"odinger equation with {\it heavy} effective mass $m_{\rm eff} = \pi T$. Starting from QED, we discuss the transition from three-- to two--dimensional positronium discussing the latter in detail including relativistic effects. In the case of QCD the problem is similar to that of heavy quarkonium. Our effective potential contains the usual Coulomb and confining parts as well as a perturbative spin--spin interaction. The resulting $\bar q q$ ``wave functions" reproduce recent lattice data for the $\rho$ and $\pi$ channels. The physical meaning of such `confinement' is related to the non--trivial magnetic interaction of color currents in the quark--gluon plasma. Our results do not contradict the idea that the normal electric interaction of color charges is screened and produces no bound states in the usual sense.Comment: 23 page

Hypersonic airframe structures: Technology needs and flight test requirements

Hypersonic vehicles, that may be produced by the year 2000, were identified. Candidate thermal/structural concepts that merit consideration for these vehicles were described. The current status of analytical methods, materials, manufacturing techniques, and conceptual developments pertaining to these concepts were reviewed. Guidelines establishing meaningful technology goals were defined and twenty-eight specific technology needs were identified. The extent to which these technology needs can be satisfied, using existing capabilities and facilities without the benefit of a hypersonic research aircraft, was assessed. The role that a research aircraft can fill in advancing this technology was discussed and a flight test program was outlined. Research aircraft thermal/structural design philosophy was also discussed. Programs, integrating technology advancements with the projected vehicle needs, were presented. Program options were provided to reflect various scheduling and cost possibilities

Analysis of pressure distortion testing

The development of a distortion methodology, method D, was documented, and its application to steady state and unsteady data was demonstrated. Three methodologies based upon DIDENT, a NASA-LeRC distortion methodology based upon the parallel compressor model, were investigated by applying them to a set of steady state data. The best formulation was then applied to an independent data set. The good correlation achieved with this data set showed that method E, one of the above methodologies, is a viable concept. Unsteady data were analyzed by using the method E methodology. This analysis pointed out that the method E sensitivities are functions of pressure defect level as well as corrected speed and pattern