Smooth-Particle Phase Stability with density and density-gradient potentials

Stable fluid and solid particle phases are essential to the simulation of continuum fluids and solids using Smooth Particle Applied Mechanics. We show that density-dependent potentials, such as Phi=(1/2)Sum (rho-rho_0)^2, along with their corresponding constitutive relations, provide a simple means for characterizing fluids and that a special stabilization potential, Phi=(1/2)Sum (delrho)^2, not only stabilizes crystalline solid phases (or meshes) but also provides a surface tension which is missing in the usual density-dependent-potential approach. We illustrate these ideas for two-dimensional square, triangular, and hexagonal lattices.Comment: 10 pages, 5 figure

Apollo experience report: Flight-control data needs, terminal display devices, and ground system configuration requirements

The development of flight-control facilities for the Apollo program is reviewed from the viewpoint of the user organization. These facilities are treated in three categories: data systems, ground-based display and control systems, and configuration management. The effects of certain Apollo program factors on the selection, sizing, and configuration management of these systems are discussed. Recommendations are made regarding improvement of the systems and the reduction of system sensitivity to the program factors

Extrusion die for refractory metals Patent

Development and characteristics of frusto-conical die nib for extrusion of refractory metal

Guide for extrusion dies eliminates straightening operation

To prevent distortion of extruded metal, a guidance assembly is aligned with the die. As the metal emerges from the extrusion dies, it passes directly into the receiver and straightening tube system, and the completed extrusion is withdrawn

The NASA -Florida State Technology Applications Center

The State Technology Applications Center (STAG) program is intended to help in the application of already-developed technology to the attack on problems of Florida\u27s business and industrial community. Designed to serve a single state\u27s industry it is unique in the nation, although a number of somewhat similar operations are being conducted in other states. It is a part of the NASA effort to promote new technology applications throughout the country with the goal of economic gain for the United States. It is an economic gain for the United States. It is an expression by the Florida DOC of its intentions to help employers of people in our state, again working for economic gain. It is a part of larger economic development activities of the State University System, to give assistance to business and industry throughout Florida. Engineers and businessmen in Florida find use for this program of information retrieval in locating documents related to their specific technical and business questions. Modern, rapid, computerized searching techniques are used to find published articles or papers in libraries throughout the United States or elsewhere. Copies of needed documents are obtained and delivered to an inquirer at surprisingly low cost. The ultimate overall goal of the program is the strengthening of Florida\u27s economy by facilitating the applications of modern technology

Evaluation of techniques for removal of spacecraft contaminants from activated carbon

Alternative techniques for the regeneration of carbon contaminated with various spacecraft contaminants were evaluated. Four different modes of regeneration were evaluated: (1) thermal desorption via vacuum, (2) thermal desorption via nitrogen purge, (3) in-situ catalytic oxidation of adsorbed contaminants, and (4) in-situ non-catalytic oxidation of adsorbed contaminants

Nonequilibrium stationary states with ratchet effect

An ensemble of particles in thermal equilibrium at temperature $T$, modeled by Nos\`e-Hoover dynamics, moves on a triangular lattice of oriented semi-disk elastic scatterers. Despite the scatterer asymmetry a directed transport is clearly ruled out by the second law of thermodynamics. Introduction of a polarized zero mean monochromatic field creates a directed stationary flow with nontrivial dependence on temperature and field parameters. We give a theoretical estimate of directed current induced by a microwave field in an antidot superlattice in semiconductor heterostructures.Comment: 4 pages, 5 figures (small changes added

The Extended Range X-Ray Telescope center director's discretionary fund report

An Extended Range X-Ray Telescope (ERXRT) of high sensitivity and spatial resolution capable of functioning over a broad region of the X-ray/XUV portion of the spectrum has been designed and analyzed. This system has been configured around the glancing-incidence Wolter Type I X-ray mirror system which was flown on the Skylab Apollo Telescope Mount as ATM Experiment S-056. Enhanced sensitivity over a vastly broader spectral range can be realized by the utilization of a thinned, back-illuminated, buried-channel Charge Coupled Device (CCD) as the X-ray/XUV detector rather than photographic film. However, to maintain the high spatial resolution inherent in the X-ray optics when a CCD of 30 micron pixel size is used, it is necessary to increase the telescope plate scale. This can be accomplished by use of a glancing-incidence X-ray microscope to enlarge and re-focus the primary image onto the focal surface of the CCD

Chaotic inflation in Jordan frame supergravity

We consider the inflationary scenario with non-minimal coupling in 4D Jordan frame supergravity. We find that there occurs a tachyonic instability along the direction of the accompanying non-inflaton field in generic Jordan frame supergravity models. We propose a higher order correction to the Jordan frame function for solving the tachyonic mass problem and show that the necessary correction can be naturally generated by the heavy thresholds without spoiling the slow-roll conditions. We discuss the implication of the result on the Higgs inflation in NMSSM.Comment: 16 pages, no figures, version to be published in JCA