11,090 research outputs found
Dependence of heat transport on the strength and shear rate of prescribed circulating flows
We study numerically the dependence of heat transport on the maximum velocity
and shear rate of physical circulating flows, which are prescribed to have the
key characteristics of the large-scale mean flow observed in turbulent
convection. When the side-boundary thermal layer is thinner than the viscous
boundary layer, the Nusselt number (Nu), which measures the heat transport,
scales with the normalized shear rate to an exponent 1/3. On the other hand,
when the side-boundary thermal layer is thicker, the dependence of Nu on the
Peclet number, which measures the maximum velocity, or the normalized shear
rate when the viscous boundary layer thickness is fixed, is generally not a
power law. Scaling behavior is obtained only in an asymptotic regime. The
relevance of our results to the problem of heat transport in turbulent
convection is also discussed.Comment: 7 pages, 7 figures, submitted to European Physical Journal
A Hybrid Quantum Encoding Algorithm of Vector Quantization for Image Compression
Many classical encoding algorithms of Vector Quantization (VQ) of image
compression that can obtain global optimal solution have computational
complexity O(N). A pure quantum VQ encoding algorithm with probability of
success near 100% has been proposed, that performs operations 45sqrt(N) times
approximately. In this paper, a hybrid quantum VQ encoding algorithm between
classical method and quantum algorithm is presented. The number of its
operations is less than sqrt(N) for most images, and it is more efficient than
the pure quantum algorithm.
Key Words: Vector Quantization, Grover's Algorithm, Image Compression,
Quantum AlgorithmComment: Modify on June 21. 10pages, 3 figure
Geology orbiter comparison study
Instrument requirements of planetary geology orbiters were examined with the objective of determining the feasibility of applying standard instrument designs to a host of terrestrial targets. Within the basic discipline area of geochemistry, gamma-ray, X-ray fluorescence, and atomic spectroscopy remote sensing techniques were considered. Within the discipline area of geophysics, the complementary techniques of gravimetry and radar were studied. Experiments using these techniques were analyzed for comparison at the Moon, Mercury, Mars and the Galilean satellites. On the basis of these comparative assessments, the adaptability of each sensing technique was judged as a basic technique for many targets, as a single instrument applied to many targets, as a single instrument used in different mission modes, and as an instrument capability for nongeoscience objectives
Quantum integrable system with two color components in two dimensions
The Davey-Stewartson 1(DS1) system[9] is an integrable model in two
dimensions. A quantum DS1 system with 2 colour-components in two dimensions has
been formulated. This two-dimensional problem has been reduced to two
one-dimensional many-body problems with 2 colour-components. The solutions of
the two-dimensional problem under consideration has been constructed from the
resulting problems in one dimensions. For latters with the -function
interactions and being solved by the Bethe ansatz, we introduce symmetrical and
antisymmetrical Young operators of the permutation group and obtain the exact
solutions for the quantum DS1 system. The application of the solusions is
discussed.Comment: 14 pages, LaTeX fil
Tramp Ship Scheduling Problem with Berth Allocation Considerations and Time-dependent Constraints
This work presents a model for the Tramp Ship Scheduling problem including
berth allocation considerations, motivated by a real case of a shipping
company. The aim is to determine the travel schedule for each vessel
considering multiple docking and multiple time windows at the berths. This work
is innovative due to the consideration of both spatial and temporal attributes
during the scheduling process. The resulting model is formulated as a
mixed-integer linear programming problem, and a heuristic method to deal with
multiple vessel schedules is also presented. Numerical experimentation is
performed to highlight the benefits of the proposed approach and the
applicability of the heuristic. Conclusions and recommendations for further
research are provided.Comment: 16 pages, 3 figures, 5 tables, proceedings paper of Mexican
International Conference on Artificial Intelligence (MICAI) 201
Some recent progress on quark pairings in dense quark and nuclear matter
We give a brief overview on some recent progress in quark pairings in dense
quark/nuclear matter mostly developed in the past five years. We focus on
following aspects in particular: the BCS-BEC crossover in the CSC phase, the
baryon formation and dissociation in dense quark/nuclear matter, the
Ginzburg-Landau theory for three-flavor dense matter with (1) anomaly,
and the collective and Nambu-Goldstone modes for the spin-one CSC.Comment: RevTex 4, 25 pages, 9 figures, presented for the KITPC (Kavli
Institute for Theoretical Physics China) program "AdS/CFT and Novel
Approaches to Hadron and Heavy Ion Physics' in Oct. 11- Dec. 3, 201
Gait Difficulty, Postural Instability, and Muscle Weakness Are Associated with Fear of Falling in People with Parkinson's Disease
The present study aimed to examine the contribution of gait impairment, postural stability and muscle weakness to the level of fear of falling in people with Parkinson's disease (PD). Fifty-seven community-dwelling individuals with PD completed the study. Fear of falling was assessed by the Activities-specific Balance Confidence (ABC) scale. Postural stability and gait difficulty were determined by the posture and gait subscores of the Unified Parkinson's Disease Rating Scale (UPDRS-PG). A Cybex dynamometer was used to measure isokinetic knee muscle strength. Individuals with PD achieved a mean ABC score of 73.6 ± 19.3. In the multiple regression analysis, after accounting for basic demographics, fall history and disease severity, the UPDRS-PG score remained independently associated with the ABC score, accounting for 13.4% of the variance (P < 0.001). The addition of knee muscle strength significantly improved the prediction model and accounted for an additional 7.3% of the variance in the ABC score (P < 0.05). This is the first study to demonstrate that the UPDRS-PG score and knee muscle strength are important and independent determinants of the level of fear of falling in individuals with PD. Improving balance, gait stability and knee muscle strength could be crucial in promoting balance confidence in the appropriately targeted PD population
Superconducting and normal-state interlayer-exchange-coupling in LaSrMnO-YBaCuO_{0.67}_{0.33}{3}$ epitaxial trilayers
The issue of interlayer exchange coupling in magnetic multilayers with
superconducting (SC) spacer is addressed in LaSrMnO
(LSMO) - YBaCuO (YBCO) - LaSrMnO
(LSMO) epitaxial trilayers through resistivity, ac-susceptibility and
magnetization measurements. The ferromagnetic (FM) LSMO layers possessing
in-plane magnetization suppress the critical temperature (T of the
c-axis oriented YBCO thin film spacer. The superconducting order, however,
survives even in very thin layers (thickness d 50 {\AA}, 4
unit cells) at T 25 K. A predominantly antiferromagnetic (AF) exchange
coupling between the moments of the LSMO layers at fields 200 Oe is seen in
the normal as well as the superconducting states of the YBCO spacer. The
exchange energy J ( 0.08 erg/cm at 150 K for d = 75
{\AA}) grows on cooling down to T, followed by truncation of this growth
on entering the superconducting state. The coupling energy J at a fixed
temperature drops exponentially with the thickness of the YBCO layer. The
temperature and d dependencies of this primarily non-oscillatory J
are consistent with the coupling theories for systems in which transport is
controlled by tunneling. The truncation of the monotonic T dependence of
J below T suggests inhibition of single electron tunneling across
the CuO planes as the in-plane gap parameter acquires a non-zero value.Comment: Accepted for publication in Phys. Rev.
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