7,969 research outputs found
On numerically accurate finite element
A general criterion for testing a mesh with topologically similar repeat units is given, and the analysis shows that only a few conventional element types and arrangements are, or can be made suitable for computations in the fully plastic range. Further, a new variational principle, which can easily and simply be incorporated into an existing finite element program, is presented. This allows accurate computations to be made even for element designs that would not normally be suitable. Numerical results are given for three plane strain problems, namely pure bending of a beam, a thick-walled tube under pressure, and a deep double edge cracked tensile specimen. The effects of various element designs and of the new variational procedure are illustrated. Elastic-plastic computation at finite strain are discussed
Avionics test bed development plan
The plan is for a facility for the early investigation and evaluation of new concepts for the control of large space structures, orbiter attached flex body experiments, and orbiter enhancements. This plan outlines a distributed data processing facility that will utilize the current JSC laboratory resources for the test bed development. The future studies required for implementation, the management system for project control, and the baseline system configuration are described
Weak Energy: Form and Function
The equation of motion for a time-independent weak value of a quantum
mechanical observable contains a complex valued energy factor - the weak energy
of evolution. This quantity is defined by the dynamics of the pre-selected and
post-selected states which specify the observable's weak value. It is shown
that this energy: (i) is manifested as dynamical and geometric phases that
govern the evolution of the weak value during the measurement process; (ii)
satisfies the Euler-Lagrange equations when expressed in terms of Pancharatnam
(P) phase and Fubini-Study (FS) metric distance; (iii) provides for a PFS
stationary action principle for quantum state evolution; (iv) time translates
correlation amplitudes; (v) generalizes the temporal persistence of state
normalization; and (vi) obeys a time-energy uncertainty relation. A similar
complex valued quantity - the pointed weak energy of an evolving state - is
also defined and several of its properties in PFS-coordinates are discussed. It
is shown that the imaginary part of the pointed weak energy governs the state's
survival probability and its real part is - to within a sign - the
Mukunda-Simon geometric phase for arbitrary evolutions or the Aharonov-Anandan
(AA) phase for cyclic evolutions. Pointed weak energy gauge transformations and
the PFS 1-form are discussed and the relationship between the PFS 1-form and
the AA connection 1-form is established.Comment: To appear in "Quantum Theory: A Two-Time Success Story"; Yakir
Aharonov Festschrif
Avionics test bed development plan
A development plan for a proposed avionics test bed facility for the early investigation and evaluation of new concepts for the control of large space structures, orbiter attached flex body experiments, and orbiter enhancements is presented. A distributed data processing facility that utilizes the current laboratory resources for the test bed development is outlined. Future studies required for implementation, the management system for project control, and the baseline system configuration are defined. A background analysis of the specific hardware system for the preliminary baseline avionics test bed system is included
Surveyor 1 mission report. Part 1 - Mission description and performance
Surveyor 1 mission discription and performance for preflight and flight phase
A feasibility study: California Department of Forestry and Fire Protection utilization of infrared technologies for wildland fire suppression and management
NASA's JPL has completed a feasibility study using infrared technologies for wildland fire suppression and management. The study surveyed user needs, examined available technologies, matched the user needs with technologies, and defined an integrated infrared wildland fire mapping concept system configuration. System component trade-offs were presented for evaluation in the concept system configuration. The economic benefits of using infrared technologies in fire suppression and management were examined. Follow-on concept system configuration development and implementation were proposed
Advanced Transport Operating System (ATOPS) control display unit software description
The software created for the Control Display Units (CDUs), used for the Advanced Transport Operating Systems (ATOPS) project, on the Transport Systems Research Vehicle (TSRV) is described. Module descriptions are presented in a standardized format which contains module purpose, calling sequence, a detailed description, and global references. The global reference section includes subroutines, functions, and common variables referenced by a particular module. The CDUs, one for the pilot and one for the copilot, are used for flight management purposes. Operations performed with the CDU affects the aircraft's guidance, navigation, and display software
Thermodynamic properties of Bi2Sr2CaCu2O8 calculated from the electronic dispersion
The electronic dispersion for Bi2Sr2CaCu2O(8+d) has been determined from
angle-resolved photoelectron spectroscopy (ARPES). From this dispersion we
calculate the entropy and superfluid density. Even with no adjustable
parameters we obtain an exceptional match with experimental data across the
entire phase diagram, thus indirectly confirming both the ARPES and
thermodynamic data. The van Hove singularity is crossed in the overdoped region
giving a distinctive linear-in-T temperature dependence in the superfluid
density there.Comment: 5 pages, 4 figures, submitted to Physical Review Letter
Development of mainshaft seals for advanced air breathing propulsion systems, phase 1 Final report, 25 Jun. 1965 - 25 Jul. 1967
Comparison of gas film mainshaft seals with rubbing contract seals for high temperature, high speed, and high pressure gas turbine application
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