Calculated tissue current-to-dose conversion factors for nucleons below 400 mev

Monte Carlo computer program for calculation of energy deposition from high incident nucleons as function of tissue slab dept

Development of a KSC test and flight engineering oriented computer language, Phase 1

Ten, primarily test oriented, computer languages reviewed during the phase 1 study effort are described. Fifty characteristics of ATOLL, ATLAS, and CLASP are compared. Unique characteristics of the other languages, including deficiencies, problems, safeguards, and checking provisions are identified. Programming aids related to these languages are reported, and the conclusions resulting from this phase of the study are discussed. A glossary and bibliography are included. For the reports on phase 2 of the study, see N71-35027 and N71-35029

Numerical study of large-eddy breakup and its effect on the drag characteristics of boundary layers

The break-up of a field of eddies by a flat-plate obstacle embedded in a boundary layer is studied using numerical solutions to the two-dimensional Navier-Stokes equations. The flow is taken to be incompressible and unsteady. The flow field is initiated from rest. A train of eddies of predetermined size and strength are swept into the computational domain upstream of the plate. The undisturbed velocity profile is given by the Blasius solution. The disturbance vorticity generated at the plate and wall, plus that introduced with the eddies, mix with the background vorticity and is transported throughout the entire flow. All quantities are scaled by the plate length, the unidsturbed free-stream velocity, and the fluid kinematic viscosity. The Reynolds number is 1000, the Blasius boundary layer thickness is 2.0, and the plate is positioned a distance of 1.0 above the wall. The computational domain is four units high and sixteen units long

An Investigation into the Geometry of Seyfert Galaxies

We present a new method for the statistical investigation into the distributions of the angle beta between the radio axis and the normal to the galactic disk for a sample of Seyfert galaxies. We discuss how further observations of the sample galaxies can strengthen the conclusions. Our data are consistent with the hypothesis that AGN jets are oriented randomly in space, independent of the position of the plane of the galaxy. By making the simple assumption that the Standard Model of AGN holds, with a universal opening angle of the thick torus of phi_c, we demonstrate a statistical method to obtain an estimate of phi_c. Our data are not consistent with the simple-minded idea that Seyfert 1s and Seyfert 2s are differentiated solely by whether or not our line of sight lies within some fixed angle of the jet axis. Our result is significant on the 2 sigma level and can thus be considered only suggestive, not conclusive. A complete sample of Seyfert galaxies selected on an isotropic property is required to obtain a conclusive result.Comment: 13 pages, Tex, 5 Postscript figures. Accepted Ap

Opportunity for All: How the American Public Benefits From Internet Access at U.S. Libraries

Examines the use of free computer and Internet access in public libraries, by income level, age, race/ethnicity, and online activity. Explores libraries' role as a community resource for social media, education, employment, e-government, and other areas

A Spherical Plasma Dynamo Experiment

We propose a plasma experiment to be used to investigate fundamental properties of astrophysical dynamos. The highly conducting, fast-flowing plasma will allow experimenters to explore systems with magnetic Reynolds numbers an order of magnitude larger than those accessible with liquid-metal experiments. The plasma is confined using a ring-cusp strategy and subject to a toroidal differentially rotating outer boundary condition. As proof of principle, we present magnetohydrodynamic simulations of the proposed experiment. When a von K\'arm\'an-type boundary condition is specified, and the magnetic Reynolds number is large enough, dynamo action is observed. At different values of the magnetic Prandtl and Reynolds numbers the simulations demonstrate either laminar or turbulent dynamo action

Pterodactyl: Thermal Protection System for Integrated Control Design of a Mechanically Deployed Entry Vehicle

The need for precision landing of high mass payloads on Mars and the return of sensitive samples from other planetary bodies to specific locations on Earth is driving the development of an innovative NASA technology referred to as the Deployable Entry Vehicle (DEV). A DEV has the potential to deliver an equivalent science payload with a stowed diameter 3 to 4 times smaller than a traditional rigid capsule configuration. However, the DEV design does not easily lend itself to traditional methods of directional control. The NASA Space Technology Mission Directorate (STMD)s Pterodactyl project is currently investigating the effectiveness of three different Guidance and Control (G&C) systems actuated flaps, Center of Gravity (CG) or mass movement, and Reaction Control System (RCS) for use with a DEV using the Adaptable, Deployable, Entry, and Placement Technology (ADEPT) design. This paper details the Thermal Protection System (TPS) design and associated mass estimation efforts for each of the G&C systems. TPS is needed for the nose cap of the DEV and the flaps of the actuated flap control system. The development of a TPS selection, sizing, and mass estimation method designed to deal with the varying requirements for the G&C options throughout the trajectory is presented. The paper discusses the methods used to i) obtain heating environments throughout the trajectory with respect to the chosen control system and resulting geometry; ii) determine a suitable TPS material; iii) produce TPS thickness estimations; and, iv) determine the final TPS mass estimation based on TPS thickness, vehicle control system, vehicle structure, and vehicle payload