443 research outputs found
Indonesia in the 21st Century: Environment at the Crossroads
This paper aims to look at Indonesia's state of the environment at the end of the second 25 year Long Term Plan (Pembangunan Jangka Panjang Kedua -PJPT II), and also aims to signal a warning for Indonesia to put things in order and not to carry on with "business as usual". The "warning" stems from the concept of the Precautionary Principle which focuses on a worst case scenario and from there makes three appeals -the need to halt pollution in advance of concrete knowledge about its impacts, the need to take responsibility for pollution that is occurring, and like this paper itself, appeals to the idea that "common sense" must prevail if development is to be sustainable
Two-component Bose gases with one-body and two-body couplings
We study the competition between one-body and two-body couplings in
weakly-interacting two-component Bose gases, in particular as regards field
correlations. We derive the meanfield theory for both ground state and
low-energy pair excitations in the general case where both one-body and
two-body couplings are position-dependent and the fluid is subjected to a
state-dependent trapping potential. General formulas for phase and density
correlations are also derived. Focusing on the case of homogeneous systems, we
discuss the pair-excitation spectrum and the corresponding excitation modes,
and use them to calculate correlation functions, including both quantum and
thermal fluctuation terms. We show that the relative phase of the two
components is imposed by that of the one-body coupling, while its fluctuations
are determined by the modulus of the one-body coupling and by the two-body
coupling. One-body coupling and repulsive two-body coupling cooperate to
suppress relative-phase fluctuations, while attractive two-body coupling tends
to enhance them. Further applications of the formalism presented here and
extensions of our work are also discussed.Comment: published versio
Entanglement entropy for the long range Ising chain
We consider the Ising model in a transverse field with long-range
antiferromagnetic interactions that decay as a power law with their distance.
We study both the phase diagram and the entanglement properties as a function
of the exponent of the interaction. The phase diagram can be used as a guide
for future experiments with trapped ions. We find two gapped phases, one
dominated by the transverse field, exhibiting quasi long range order, and one
dominated by the long range interaction, with long range N\'eel ordered ground
states. We determine the location of the quantum critical points separating
those two phases. We determine their critical exponents and central-charges. In
the phase with quasi long range order the ground states exhibit exotic
corrections to the area law for the entanglement entropy coexisting with gapped
entanglement spectra.Comment: 5 pages, all comments welcom
Investigation of afterburner combustion screech and methods of its control at high combustor pressure levels
Control of high pressure combustion screech in afterburne
Air-flow Characteristics of Brazed and Rolled Wire Filter Cloth for Transpiration-cooled Afterburners
Cooling Characteristics of a Transpiration-cooled Afterburner with a Porous Wall of Brazed and Rolled Wire Cloth
Preliminary Experimental Investigation of Transpiration Cooling for an Afterburner with a Sintered, Porous Stainless-steel Combustion-chamber Wall
Cooling characteristics of a transpiration-cooled afterburner with a porous wall of brazed and rolled wire cloth
Investigation of the I-40 Jet-propulsion Engine in the Cleveland Altitude Wind Tunnel I : Performance and Windmilling Drag Characteristics
Chart for Simplifying Calculations of Pressure Drop of a High-Speed Compressible Fluid Under Simultaneous Action of Friction and Heat Transfer - Application to Combustion-Chamber Cooling Passages
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