27,924 research outputs found
The Optimal Rate of Decline of an Inefficient Industry
This paper considers the problem of the optimal time path of contraction of an industry which has been hit by foreign competition, and shows that in general, along the optimal path, a production subsidy is warranted. The optimal subsidy trades off the benefit of unemployment in speeding up the approach to the new long-run equilibrium against the cost of lost output in the âinefficientâ industry. The dynamic shadow price of labour in this industry is also derived and shown to be always positive, though below the industry wage rat
A semiclassical theory of quantum noise in open chaotic systems
We consider the quantum evolution of classically chaotic systems in contact
with surroundings. Based on -scaling of an equation for time evolution
of the Wigner's quasi-probability distribution function in presence of
dissipation and thermal diffusion we derive a semiclassical equation for
quantum fluctuations. This identifies an early regime of evolution dominated by
fluctuations in the curvature of the potential due to classical chaos and
dissipation. A stochastic treatment of this classical fluctuations leads us to
a Fokker-Planck equation which is reminiscent of Kramers' equation for
thermally activated processes. This reveals an interplay of three aspects of
evolution of quantum noise in weakly dissipative open systems; the reversible
Liouville flow, the irreversible chaotic diffusion which is characteristic of
the system itself, and irreversible dissipation induced by the external
reservoir. It has been demonstrated that in the dissipation-free case a
competition between Liouville flow in the contracting direction of phase space
and chaotic diffusion sets a critical width in the Wigner function for quantum
fluctuations. We also show how the initial quantum noise gets amplified by
classical chaos and ultimately equilibrated under the influence of dissipation.
We establish that there exists a critical limit to the expansion of phase
space. The limit is determined by chaotic diffusion and dissipation. Making use
of appropriate quantum-classical correspondence we verify the semiclassical
analysis by the fully quantum simulation in a chaotic quartic oscillator.Comment: Plain Latex, 27 pages, 6 ps figure, To appear in Physica
Observation of thermo-mechanical equilibration in the presence of a solid 4He conduit
We observe a thermo-mechanical effect when a chemical potential difference is
created by a temperature difference imposed between two liquid reservoirs
connected to each other through Vycor rods in series with solid hcp 4He. By
creating a temperature difference, , between the two reservoirs, we
induce a rate-limited growth of a pressure difference between the two
reservoirs, . In equilibrium is in
quantitative agreement with the thermo-mechanical effect in superfluid helium.
These observations confirm that below 600 mK a flux-limited flow exists
through the solid helium.Comment: 4 pages, 4 figure
Technical productivity analysis for cement industry at firm level
This paper analyses the energy use in the manufacture of cement in India during 1992-2005. Cement manufacturing requires large amounts of various energy inputs. The most common types of energy carriers used are coal, electricity, natural gas and fuel oil. Over the years, the fuel use shift is less, but use of natural gas has decreased and that of electricity has increased. Using panel data, stochastic frontier production function method has been used to evaluate the efficiency of individual firms and industries across the years. The results show a significant decrease in energy as well as carbon intensities because of differences in production techniques.Cement industry, Energy demand, Firm, Technical efficiency
Wind-tunnel Tests of a Cyclogiro Rotor
During an extensive study of all types of rotating wings, the NACA examined the cyclogiro rotor and made an aerodynamic analysis of that system (reference 1). The examination disclosed that such a machine had sufficient promise to justify an experimental investigation; a model with a diameter and span of 8 feet was therefore constructed and tested in the 20-foot wind tunnel during 1934. The experimental work included tests of the effect of the motion upon the rotor forces during the static-lift and forward-flight conditions at several rotor speeds and the determination of the relations between the forces generated by the rotor and the power required by it
- âŠ