2,940 research outputs found
"The Financially Fragile Firm: Is There a Case for It in the 1920s?"
This paper is an empirical investigation of Minsky's hypothesis in the U.S. consumer durables sector during the 1920s. The first section of the paper briefly describes Minsky's financial fragility hypothesis, while the second sketches a brief economic historical background of the 1920s in the U.S. The third section introduces the methodology utilized and the fourth presents the results of the analysis. In the conclusion the findings and their implications are summarized.
Report of activities of the advanced coal extraction systems definition project, 1979 - 1980
During this period effort was devoted to: formulation of system performance goals in the areas of production cost, miner safety, miner health, environmental impact, and coal conservation, survey and in depth assessment of promising technology, and characterization of potential resource targets. Primary system performance goals are to achieve a return on incremental investment of 150% of the value required for a low risk capital improvement project and to reduce deaths and disability injuries per million man-hour by 50%. Although these performance goals were developed to be immediately applicable to the Central Appalachian coal resources, they were also designed to be readily adaptable to other coals by appending a geological description of the new resource. The work done on technology assessment was concerned with the performance of the slurry haulage system
A study of electronic packages environmental control systems and vehicle thermal systems integration Quarterly report, Nov. 1966 - Jan. 1967
Heat balances of combined astrionic equipment and thermal conditioning subsystem of environmental control system, and vehicle configuration
Near-Constant Mean Curvature Solutions of the Einstein Constraint Equations with Non-Negative Yamabe Metrics
We show that sets of conformal data on closed manifolds with the metric in
the positive or zero Yamabe class, and with the gradient of the mean curvature
function sufficiently small, are mapped to solutions of the Einstein constraint
equations. This result extends previous work which required the conformal
metric to be in the negative Yamabe class, and required the mean curvature
function to be nonzero.Comment: 15 page
Asymptotically Hyperbolic Non Constant Mean Curvature Solutions of the Einstein Constraint Equations
We describe how the iterative technique used by Isenberg and Moncrief to
verify the existence of large sets of non constant mean curvature solutions of
the Einstein constraints on closed manifolds can be adapted to verify the
existence of large sets of asymptotically hyperbolic non constant mean
curvature solutions of the Einstein constraints.Comment: 19 pages, TeX, no figure
The constraint equations for the Einstein-scalar field system on compact manifolds
We study the constraint equations for the Einstein-scalar field system on
compact manifolds. Using the conformal method we reformulate these equations as
a determined system of nonlinear partial differential equations. By introducing
a new conformal invariant, which is sensitive to the presence of the initial
data for the scalar field, we are able to divide the set of free conformal data
into subclasses depending on the possible signs for the coefficients of terms
in the resulting Einstein-scalar field Lichnerowicz equation. For many of these
subclasses we determine whether or not a solution exists. In contrast to other
well studied field theories, there are certain cases, depending on the mean
curvature and the potential of the scalar field, for which we are unable to
resolve the question of existence of a solution. We consider this system in
such generality so as to include the vacuum constraint equations with an
arbitrary cosmological constant, the Yamabe equation and even (all cases of)
the prescribed scalar curvature problem as special cases.Comment: Minor changes, final version. To appear: Classical and Quantum
Gravit
Binary neutron stars: Equilibrium models beyond spatial conformal flatness
Equilibria of binary neutron stars in close circular orbits are computed
numerically in a waveless formulation: The full Einstein-relativistic-Euler
system is solved on an initial hypersurface to obtain an asymptotically flat
form of the 4-metric and an extrinsic curvature whose time derivative vanishes
in a comoving frame. Two independent numerical codes are developed, and
solution sequences that model inspiraling binary neutron stars during the final
several orbits are successfully computed. The binding energy of the system near
its final orbit deviates from earlier results of third post-Newtonian and of
spatially conformally flat calculations. The new solutions may serve as initial
data for merger simulations and as members of quasiequilibrium sequences to
generate gravitational wave templates, and may improve estimates of the
gravitational-wave cutoff frequency set by the last inspiral orbit.Comment: 4 pages, 6 figures, revised version, PRL in pres
Asymptotic gluing of asymptotically hyperbolic solutions to the Einstein constraint equations
We show that asymptotically hyperbolic solutions of the Einstein constraint
equations with constant mean curvature can be glued in such a way that their
asymptotic regions are connected.Comment: 37 pages; 2 figure
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