9,798 research outputs found

    Consistent forcing scheme in the cascaded lattice Boltzmann method

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    In this paper, we give a more pellucid derivation for the cascaded lattice Boltzmann method (CLBM) based on a general multiple-relaxation-time (MRT) frame through defining a shift matrix. When the shift matrix is a unit matrix, the CLBM degrades into an MRT LBM. Based on this, a consistent forcing scheme is developed for the CLBM. The applicability of the non-slip rule, the second-order convergence rate in space and the property of isotropy for the consistent forcing scheme is demonstrated through the simulation of several canonical problems. Several other existing force schemes previously used in the CLBM are also examined. The study clarifies the relation between MRT LBM and CLBM under a general framework

    Discovery and Testimony of Unretained Experts: Creating a Clear and Equitable Standard to Govern Compliance With Subpoenas

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    Hearing impairment is known to be one of the most frequent sensory impairments. This condition is known to be a hidden disorder which is under recognised and under treated all around the world. The World Health Organisation (WHO) estimates suggest that there are over 275 million people with hearing impairment and 80% of them living in low and middle income countries. Moreover, the estimates suggest that incidence and prevalence of hearing loss and also the number of people with hearing loss accessing services varies considerably across countries. This rises the need for health promotion (or public awareness campaigns) directed to increase awareness and education of hearing loss and hearing healthcare. This paper provides brief discussion on ‘Stories and storytelling’, ‘Cross-culture and cross-cultural communication’ and ‘Health promotion and cultural sensitivity’. The central focus of this paper is to highlight the applications of storytelling in different cultural context in health promotion, particularly to hearing loss public awareness campaigns

    First-principles determined charge and orbital interactions in Fe3_3O4_4

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    The interactions between charge and orbitally ordered dd-electrons are important in many transition metal oxides. We propose an effective energy model for such interactions, parameterized with DFT+U calculations, so that energy contributions of both electronic and lattice origin can be simultaneously accounted for. The model is applied to the low-temperature phase of magnetite, for which we propose a new ground state structure. The effective interactions on the B-lattice of Fe3_3O4_4 can be interpreted in terms of electrostatics and short-range Kugel-Khomskii exchange coupling. The frustration between optimal charge and orbital orderings leads to a complex energy landscape whereby the supercell for the charge ordering, orbital ordering and ionic displacements can all be different.Comment: 15 pages, 4 figure

    Yield Enhancement of Digital Microfluidics-Based Biochips Using Space Redundancy and Local Reconfiguration

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    As microfluidics-based biochips become more complex, manufacturing yield will have significant influence on production volume and product cost. We propose an interstitial redundancy approach to enhance the yield of biochips that are based on droplet-based microfluidics. In this design method, spare cells are placed in the interstitial sites within the microfluidic array, and they replace neighboring faulty cells via local reconfiguration. The proposed design method is evaluated using a set of concurrent real-life bioassays.Comment: Submitted on behalf of EDAA (http://www.edaa.com/

    Traffic congestion in interconnected complex networks

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    Traffic congestion in isolated complex networks has been investigated extensively over the last decade. Coupled network models have recently been developed to facilitate further understanding of real complex systems. Analysis of traffic congestion in coupled complex networks, however, is still relatively unexplored. In this paper, we try to explore the effect of interconnections on traffic congestion in interconnected BA scale-free networks. We find that assortative coupling can alleviate traffic congestion more readily than disassortative and random coupling when the node processing capacity is allocated based on node usage probability. Furthermore, the optimal coupling probability can be found for assortative coupling. However, three types of coupling preferences achieve similar traffic performance if all nodes share the same processing capacity. We analyze interconnected Internet AS-level graphs of South Korea and Japan and obtain similar results. Some practical suggestions are presented to optimize such real-world interconnected networks accordingly.Comment: 8 page

    Modeling incompressible thermal flows using a central-moment-based lattice Boltzmann method

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    In this paper, a central-moment-based lattice Boltzmann (CLB) method for incompressible thermal flows is proposed. In the method, the incompressible Navier-Stokes equations and the convection-diffusion equation for the temperature field are sloved separately by two different CLB equations. Through the Chapman-Enskog analysis, the macroscopic governing equations for incompressible thermal flows can be reproduced. For the flow field, the tedious implementation for CLB method is simplified by using the shift matrix with a simplified central-moment set, and the consistent forcing scheme is adopted to incorporate forcing effects. Compared with several D2Q5 multiple-relaxation-time (MRT) lattice Boltzmann methods for the temperature equation, the proposed method is shown to be better Galilean invariant through measuring the thermal diffusivities on a moving reference frame. Thus a higher Mach number can be used for convection flows, which decreases the computational load significantly. Numerical simulations for several typical problems confirm the accuracy, efficiency, and stability of the present method. The grid convergence tests indicate that the proposed CLB method for incompressible thermal flows is of second-order accuracy in space

    "Black Star" or Astrophysical Black Hole?

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    Recently wide publicity has been given to a claim by T. Vachaspati that "black holes do not exist", that the objects known as black holes in astrophysics should rather be called "black stars" and they not only do not have event horizons but actually can be the source of spectacular gamma ray bursts. In this short essay (no flimsier than the original preprint where these extravagant claims appeared) I demonstrate that these ill-considered claims are clearly wrong. Yet they present a good occasion to reflect on some well known but little discussed conceptual difficulties which arise when applying relativistic terminology in an astrophysical context.Comment: Poster presented at "Compact Objects" meeting in Hunagshan, China, 2-7 July 2007. To be published in the AIP Conference Proceeding serie

    Concurrence of arbitrary dimensional bipartite quantum states

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    We derive an analytical lower bound for the concurrence of a bipartite quantum state in arbitrary dimension. A functional relation is established relating concurrence, the Peres-Horodecki criterion and the realignment criterion. We demonstrate that our bound is exact for some mixed quantum states. The significance of our method is illustrated by giving a quantitative evaluation of entanglement for many bound entangled states, some of which fail to be identified by the usual concurrence estimation method.Comment: 4 pages, published versio

    BRST Structures and Symplectic Geometry on a Class of Supermanifolds

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    By investigating the symplectic geometry and geometric quantization on a class of supermanifolds, we exhibit BRST structures for a certain kind of algebras. We discuss the undeformed and q-deformed cases in the classical as well as in the quantum cases.Comment: 14 pages, Late
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