39,574 research outputs found
Issues in management of artificial intelligence based projects
Now that Artificial Intelligence (AI) is gaining acceptance, it is important to examine some of the obstacles that still stand in the way of its progress. Ironically, many of these obstacles are related to management and are aggravated by the very characteristcs that make AI useful. The purpose of this paper is to heighten awareness of management issues in AI development and to focus attention on their resolution
Thrust chamber performance using Navier-Stokes solution
The viscous, axisymmetric flow in the thrust chamber of the space shuttle main engine (SSME) was computed on the CRAY 205 computer using the general interpolants method (GIM) code. Results show that the Navier-Stokes codes can be used for these flows to study trends and viscous effects as well as determine flow patterns; but further research and development is needed before they can be used as production tools for nozzle performance calculations. The GIM formulation, numerical scheme, and computer code are described. The actual SSME nozzle computation showing grid points, flow contours, and flow parameter plots is discussed. The computer system and run times/costs are detailed
Large anisotropy in the optical conductivity of YNi2B2C
The optical properties of YNiBC are studied by using the
first-principles full-potential linearized augmented plane wave (FLAPW) method
within the local density approximation. Anisotropic behavior is obtained in the
optical conductivity, even though the electronic structure shows 3D character.
A large peak in is obtained at 2.4 eV. The anisotropic optical
properties are analyzed in terms of interband transitions between energy levels
and found that the Ni site plays an important role. The electronic energy loss
spectroscopy (EELS) spectra are also calculated to help elucidate the
anisotropic properties in this system.Comment: revtex4, 4 pages, 5 figures, to appear in PR
First-principles characterization of ferromagnetic Mn5Ge3 for spintronic applications
In the active search for potentially promising candidates for spintronic
applications, we focus on the intermetallic ferromagnetic Mn5Ge3 compound and
perform accurate first-principles FLAPW calculations within density functional
theory. Through a careful investigation of the bulk electronic and magnetic
structure, our results for the total magnetization, atomic magnetic moments,
metallic conducting character and hyperfine fields are found to be in good
agreement with experiments, and are elucidated in terms of a hybridization
mechanism and exchange interaction. In order to assess the potential of this
compound for spin-injection purposes, we calculate Fermi velocities and degree
of spin-polarization; our results predict a rather high spin-injection
efficiency in the diffusive regime along the hexagonal c-axis. Magneto-optical
properties, such as L_2,3 X-ray magnetic circular dichroism, are also reported
and await comparison with experimental data.Comment: 10 pages with 6 figures, to appear in Phys. Rev.
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