128 research outputs found
Generalized Quantum Dynamics as Pre-Quantum Mechanics
We address the issue of when generalized quantum dynamics, which is a
classical symplectic dynamics for noncommuting operator phase space variables
based on a graded total trace Hamiltonian , reduces to Heisenberg
picture complex quantum mechanics. We begin by showing that when , with a Weyl ordered operator Hamiltonian, then the generalized
quantum dynamics operator equations of motion agree with those obtained from
in the Heisenberg picture by using canonical commutation relations. The
remainder of the paper is devoted to a study of how an effective canonical
algebra can arise, without this condition simply being imposed by fiat on the
operator initial values. We first show that for any total trace Hamiltonian
which involves no noncommutative constants, there is a conserved
anti--self--adjoint operator with a structure which is closely
related to the canonical commutator algebra. We study the canonical
transformations of generalized quantum dynamics, and show that is a
canonical invariant, as is the operator phase space volume element. The latter
result is a generalization of Liouville's theorem, and permits the application
of statistical mechanical methods to determine the canonical ensemble governing
the equilibrium distribution of operator initial values. We give arguments
based on a Ward identity analogous to the equipartition theorem of classical
statistical mechanics, suggesting that statistical ensemble averages of Weyl
ordered polynomials in the operator phase space variables correspond to the
Wightman functions of a unitary complex quantum mechanics, with a conserved
operator Hamiltonian and with the standard canonical commutation relations
obeyed by Weyl ordered operator strings. Thus there is a well--defined sense inComment: 79 pages, no figures, plain te
Microsphere Insulation Panels
Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum
Miniature reciprocating heat pumps and engines
The present invention discloses a miniature thermodynamic device that can be constructed using standard micro-fabrication techniques. The device can be used to provide cooling, generate power, compress gases, pump fluids and reduce pressure below ambient (operate as a vacuum pump). Embodiments of the invention relating to the production of a cooling effect and the generation of electrical power, change the thermodynamic state of the system by extracting energy from a pressurized fluid. Energy extraction is attained using an expansion process, which is as nearly isentropic as possible for the appropriately chosen fluid. An isentropic expansion occurs when a compressed gas does work to expand, and in the disclosed embodiments, the gas does work by overcoming either an electrostatic or a magnetic force
Microsphere insulation systems
A new insulation system is provided that contains microspheres. This insulation system can be used to provide insulated panels and clamshells, and to insulate annular spaces around objects used to transfer, store, or transport cryogens and other temperature-sensitive materials. This insulation system provides better performance with reduced maintenance than current insulation systems
Upper limit on the transition temperature for non-ideal Bose gases
In this paper we show that for a non-ideal Bose gas there exists an upper
limit on the transition temperature above which Bose-Einstein condensation
cannot occur regardless of the pressure applied. Such upper limits for some
realistic Bose gases are estimated. This result implies that there may also
exist an upper limit on the transition temperature of superconductors.Comment: 7 pages, 1 figur
Evaluation of mechanical and thermal nociception as objective tools to measure painful and nonpainful lameness phases in multiparous sows
The objective of this study was to quantify pain sensitivity differences using mechanical nociception threshold (MNT) and thermal nociception threshold (TNT) tests when sows were in painful and nonpainful transient lameness phases. A total of 24 mixed parity crossbred sows (220.15 ± 21.23 kg) were utilized for the MNT test, and a total of 12 sows (211.41 ± 20.21 kg) were utilized for the TNT test. On induction day (D0), all sows were anesthetized and injected with Amphotericin B (10mg/mL) in the distal interphalangeal joint space in both claws of one randomly selected hind limb to induce transient lameness. Three days were compared: (1) D-1 (sound phase, defined as 1 d before induction), (2) D+1 (most lame phase, defined as 1 d after induction), and (3) D+6 (resolution phase, defined as 6 d after induction). After completion of the first round, sows were given a 7-d rest period and then the procedures were repeated with lameness induced in the contralateral hind limb. During the MNT test, pressure was applied perpendicularly to 3 landmarks in a randomized sequence for each sow: 1) middle of cannon on the hind limb (cannon), 2) 1 cm above the coronary band on the medial hind claw (medial claw), and 3) 1 cm above the coronary band on the lateral hind claw (lateral claw). During the TNT test, a radiant heat stimulus was directed 1 cm above the coronary band. The data were analyzed using the MIXED procedure in SAS with sow as the experimental unit. Differences were analyzed between sound and lame limbs on each day. For the MNT test, pressure tolerated by the lame limb decreased for every landmark (P \u3c 0.05) when comparing D-1 and D+1. The sound limb tolerated more pressure on D+1 and D+6 than on baseline D-1 (P \u3c 0.05). Thermal stimulation tolerated by the sound limb did not change over the 3 d (P \u3e 0.05). However, the sows tolerated less heat stimulation on their lame limb on D+1 compared to D-1 levels (P \u3c 0.05). Both MNT and TNT tests indicated greater pain sensitivity thresholds when sows were acutely lame
Numerical computation of the hypersonic rarefied flow past the sharp leading edge of a flat plate
Mesoscopic modeling of a two-phase flow in the presence of boundaries: the Contact Angle
We present a mesoscopic model, based on the Boltzmann Equation, for the
interaction between a solid wall and a non-ideal fluid. We present an analytic
derivation of the contact angle in terms of the surface tension between the
liquid-gas, the liquid-solid and the gas-solid phases. We study the dependency
of the contact angle on the two free parameters of the model, which determine
the interaction between the fluid and the boundaries, i.e. the equivalent of
the wall density and of the wall-fluid potential in Molecular Dynamics studies.
We compare the analytical results obtained in the hydrodynamical limit for
the density profile and for the surface tension expression with the numerical
simulations. We compare also our two-phase approach with some exact results for
a pure hydrodynamical incompressible fluid based on Navier-Stokes equations
with boundary conditions made up of alternating slip and no-slip strips.
Finally, we show how to overcome some theoretical limitations connected with a
discretized Boltzmann scheme and we discuss the equivalence between the surface
tension defined in terms of the mechanical equilibrium and in terms of the
Maxwell construction.Comment: 29 pages, 12 figure
The use of kinematic and nociceptive threshold tests to discriminate between lameness phases in multiparous sows
The objective of this thesis was to determine if four tools were able to quantify differences in lameness phases in multiparous sows. The tools evaluated in this study included thermal and mechanical nociceptive threshold tests, an embedded force plate and a GAITFour gait analysis walkway system. Observed results from these studies indicate that all four tools were able to quantify differences between sound and most lame phases in multiparous sows. In conclusion, this research provides additional tools that can be used to detect varying lameness states in multiparous sows
Fluctuations and correlations in an individual-based model of biological coevolution
We extend our study of a simple model of biological coevolution to its
statistical properties. Staring with a complete description in terms of a
master equation, we provide its relation to the deterministic evolution
equations used in previous investigations. The stationary states of the
mutationless model are generally well approximated by Gaussian distributions,
so that the fluctuations and correlations of the populations can be computed
analytically. Several specific cases are studied by Monte Carlo simulations,
and there is excellent agreement between the data and the theoretical
predictions.Comment: 25 pages, 2 figure
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