91,656 research outputs found
Superintegrability of the Tremblay-Turbiner-Winternitz quantum Hamiltonians on a plane for odd
In a recent FTC by Tremblay {\sl et al} (2009 {\sl J. Phys. A: Math. Theor.}
{\bf 42} 205206), it has been conjectured that for any integer value of ,
some novel exactly solvable and integrable quantum Hamiltonian on a plane
is superintegrable and that the additional integral of motion is a th-order
differential operator . Here we demonstrate the conjecture for the
infinite family of Hamiltonians with odd , whose first member
corresponds to the three-body Calogero-Marchioro-Wolfes model after elimination
of the centre-of-mass motion. Our approach is based on the construction of some
-extended and invariant Hamiltonian \chh_k, which can be interpreted
as a modified boson oscillator Hamiltonian. The latter is then shown to possess
a -invariant integral of motion \cyy_{2k}, from which can be
obtained by projection in the identity representation space.Comment: 14 pages, no figure; change of title + important addition to sect. 4
+ 2 more references + minor modifications; accepted by JPA as an FT
Investigation of plasma accelerator /cyclotron resonance propulsion system/ Final report
Electron cyclotron resonance plasma accelerators for space propulsion system
Landau Ginzburg Theory and Nuclear Matter at Finite Temperature
Based on recent studies of the temperature dependence of the energy and
specific heat of liquid nuclear matter, a phase transition is suggested at a
temperature MeV. We apply Landau Ginzburg theory to this transition
and determine the behaviour of the energy and specific heat close to the
critical temperature in the condensed phase.Comment: 10 pages, Revte
An experimental study of counter-rotating cores in elliptical galaxies
Recent observational studies (Franx and Illingworth 1987; Jedrzejewski and Schechter 1988; Bender 1988; Illingworth and Franx 1989) have shown that some elliptical galaxies have a small region near the center that rotates in the opposite direction from the outer parts of the galaxy. Often the rotation in the central part is much faster than that in the outer part. A few other galaxies show a small region near the center that rotates in the same direction as the rest of the galaxy, but much faster. Either way, the part near the center that shows a strange pattern of rotation (the 'core') has been interpreted as a distinct dynamical subsystem. Very briefly, the observational data seem to be that anomalies show up in rotation curves near the centers of some elliptical galaxies and that galaxies with these strange rotational properties do not show a photometric signature: there are no noticeable bumps in the brightness profile and no unusual shapes of isophotal contours that would suggest an excess of matter concentrated near the center. No strong color variations have been reported. The puzzle is to learn what we can about elliptical galaxies in general, and about galaxies with strange central regions in particular, from these observational facts. The authors' approach is experimental. They make a guess about the form of the dynamically distinct subsystem, and then build a galaxy model to test experimental consequences such as the amount of matter required to produce observable effects and the length of time over which these effects would remain observable. They sidestep questions about how the galaxy might have gotten to be that way in the first place. That gives them more freedom to explore a variety of suggestions about what kind of dynamical system might give rise to the observed rotational patterns
Cometary particulate analyzer
A concept for determining the relative abundance of elements contained in cometary particulates was evaluated. The technique utilizes a short, high intensity burst of laser radiation to vaporize and ionize collected particulate material. Ions extracted from this laser produced plasma are analyzed in a time of flight mass spectrometer to yield an atomic mass spectrum representative of the relative abundance of elements in the particulates. Critical aspects of the development of this system are determining the ionization efficiencies for various atomic species and achieving adequate mass resolution. A technique called energy-time focus, which utilizes static electric fields to alter the length of the ion flight path in proportion to the ion initial energy, was used which results in a corresponding compression to the range of ion flight times which effectively improves the inherent resolution. Sufficient data were acquired to develop preliminary specifications for a flight experiment
Research on processes for utilization of lunar resources quarterly report, 16 jul. - 15 oct. 1964
Lunar resource utilization - silicate reduction unit and carbon monoxide reduction reacto
Microwave Driven Magnetic Plasma Accelerator Studies (CYCLOPS)
A microwave-driven cyclotron resonance plasma acceleration device was investigated using argon, krypton, xenon, and mercury as propellants. Limited ranges of propellant flow rate, input power, and magnetic field strength were used. Over-all efficiencies (including the 65% efficiency of the input polarizer) less than 10% were obtained for specific impulse values between 500 and 1500 sec. Power transfer efficiencies, however, approached 100% of the input power available in the right-hand component of the incident circularly polarized radiation. Beam diagnostics using Langmuir probes, cold gas mapping, r-f mapping and ion energy analyses were performed in conjunction with an engine operating in a pulsed mode. Measurements of transverse electron energies at the position of cyclotron resonant absorption yielded energy values more than an order of magnitude lower than anticipated. The measured electron energies were, however, consistent with the low values of average ion energy measured by retarding potential techniques. The low values of average ion energy were also consistent with the measured thrust values. It is hypothesized that ionization and radiation limit the electron kinetic energy to low-values thus limiting the energy which is finally transferred to the ion. Thermalization by electron-electron collision was also identified as an additional loss mechanism. The use of light alkali metals, which have relatively few low lying energy levels to excite, with the input power to mass ratio selected so as to limit the electron energies to less than the second ionization potential, is suggested. It is concluded, however, that the over-all efficiency for such propellants would be less than 40 per cent
Applications of thermal energy storage in the cement industry
In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, established use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10 to the 13th power Btu/year, or an equivalent on investment of the proposed systems are an incentive for further development
Army ants algorithm for rare event sampling of delocalized nonadiabatic transitions by trajectory surface hopping and the estimation of sampling errors by the bootstrap method
The most widely used algorithm for Monte Carlo sampling of electronic transitions in trajectory surface hopping (TSH) calculations is the so-called anteater algorithm, which is inefficient for sampling low-probability nonadiabatic events. We present a new sampling scheme (called the army ants algorithm) for carrying out TSH calculations that is applicable to systems with any strength of coupling. The army ants algorithm is a form of rare event sampling whose efficiency is controlled by an input parameter. By choosing a suitable value of the input parameter the army ants algorithm can be reduced to the anteater algorithm (which is efficient for strongly coupled cases), and by optimizing the parameter the army ants algorithm may be efficiently applied to systems with low-probability events. To demonstrate the efficiency of the army ants algorithm, we performed atom–diatom scattering calculations on a model system involving weakly coupled electronic states. Fully converged quantum mechanical calculations were performed, and the probabilities for nonadiabatic reaction and nonreactive deexcitation (quenching) were found to be on the order of 10^–8. For such low-probability events the anteater sampling scheme requires a large number of trajectories (~10^10) to obtain good statistics and converged semiclassical results. In contrast by using the new army ants algorithm converged results were obtained by running 10^5 trajectories. Furthermore, the results were found to be in excellent agreement with the quantum mechanical results. Sampling errors were estimated using the bootstrap method, which is validated for use with the army ants algorithm
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