On Rigidity of 3d Asymptotic Symmetry Algebras

We study rigidity and stability of infinite dimensional algebras which are not subject to the Hochschild-Serre factorization theorem. In particular, we consider algebras appearing as asymptotic symmetries of three dimensional spacetimes, the BMS3, u(1) Kac-Moody and Virasoro algebras. We construct and classify the family of algebras which appear as deformations of BMS3, u(1) Kac-Moody and their central extensions by direct computations and also by cohomological analysis. The Virasoro algebra appears as a specific member in this family of rigid algebras; for this case stabilization procedure is inverse of the In\"on\"u-Wigner contraction relating Virasoro to BMS3 algebra. We comment on the physical meaning of deformation and stabilization of these algebras and relevance of the family of rigid algebras we obtainComment: 50 pages, one figure and two tables; v2: minor improvements, references adde

Modification of as-cast Al-Mg/B4C composite by addition of Zr

Zirconium was used in Al-Mg/B4C composite to improve compocasting efficiency by increasing particle incorporation. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) results revealed that by addition of zirconium a reaction layer containing Zr, Al, B and C is formed on the interface of B4C-matrix. X-ray diffraction (XRD) analysis of extracted particles unveiled that the ZrB2 phase is the main constituent of this layer. Formation of ZrB2 is an exothermic reaction which can rise temperature locally around particles and agglomerates. Rising temperature around agglomerates in conjunction with turbulent flow of melt facilitates agglomerates wetting and dissolving into molten aluminum. As the result, final product contains more uniformly distributed B4C particles. Besides enhancing compocasting efficiency, addition of Zr and formation of reaction layer by improving particle matrix bonding quality, led to increase in ultimate tensile strength and elongation of the composite around 8% and 30%, respectively. SEM observations of the fracture surfaces confirmed that a proper bonding presents at the interface of particles and matrix in presence of Zr.Peer ReviewedPostprint (author's final draft

Foundation Sign Correction in Stochastic Analysis Procedures

There are “ABS, SRSS, CQC, MSRSS…” methods in stochastic analysis of structures, that are based on the mean of the response squares. One of the most accurate stochastic methods is MSRSS, that is defined as equation (1). E[y2]=∑j=1N Rj2 + 2 ∑k=j+1NRjk The maximum modal responses are positive or singles, and therefore direction of the forces act on the foundation are alike. In these cases foundation analysis is not valid and the force sign correction must be used. In this paper, besides considering the stochastic methods shortly, a method for sign correction based on the time history analysis will be presented

Numerical analysis to quantify the influence of smear zone characteristics on preloading design in soft clay

In this paper, the effects of uncertainties of smear zone characteristics induced by installation of prefabricated vertical drains on the preloading design are numerically investigated. FLAC 2D finite difference software with additional developed subroutines has been employed to conduct the numerical simulations. The finite difference analyses have been verified using a case study. Furthermore, a comprehensive parametric study is conducted to investigate the influence of smear zone permeability and extent on the model predictions. Results of this study indicate that the assumptive properties for smear zone characteristics may result in inaccurate predictions of ground deformations and pore water pressures. This may lead to early removal of the surcharge in the construction process causing excessive post construction settlement. It is recommended to practising engineers to use results of trial preloading to back calculate the required smear zone characteristics in the early stages of embankment construction to optimize the design

Uncertainties of Smear Zone Characteristics in the Design of Preloading with Prefabricated Vertical Drains

Installing prefabricated vertical drains using mandrels induces disturbance of the soil surrounding the drain, resulting in a smear zone with the reduced permeability. The required time for pore pressure dissipation in preloading design is strongly associated with the smear zone characteristics. In this study, the effects of smear zone properties on preloading time are numerically investigated. Parametric study is conducted to find out the range of smear zone parameters significantly influencing the consolidation period. It is observed that the characteristics of smear zone namely size and permeability have a substantial impact on the preloading design to achieve certain soil strength and stiffness satisfying both bearing capacity and settlement design criteria

Techniques for data prediction, smoothing, and updating of operator errors in commercial nuclear power plants

http://www.worldcat.org/oclc/533896

Analyzing consolidation data to predict smear zone characteristics induced by vertical drain installation for soft soil improvement

In this paper, the effects of variability of smear zone characteristics induced by installation of prefabricated vertical drains on the preloading design are investigated employing analytical and numerical approaches. Conventional radial consolidation theory has been adopted to conduct analytical parametric studies considering variations of smear zone permeability and extent. FLAC 2D finite difference software has been employed to conduct the numerical simulations. The finite difference analyses have been verified using three case studies including two embankments and a large-scale laboratory consolidometer with a central geosynthetic vertical drain. A comprehensive numerical parametric study is conducted to investigate the influence of smear zone permeability and extent on the model predictions. Furthermore, the construction of the trial embankment is recommended as a reliable solution to estimate accurate smear zone properties and minimise the post construction settlement. A back-calculation procedure is employed to determine the minimum required waiting time after construction of the trial embankment to predict the smear zone characteristics precisely. Results of this study indicate that the accurate smear zone permeability and extent can be back-calculated when 30% degree of consolidation is obtained after construction of the trial embankment. © 2014 Techno-Press, Ltd

Coulomb Blockade Doppelgangers in Quantum Hall States

In this paper, we ask the question: How well can Coulomb blockade experiments correctly identify and distinguish between different topological orders in quantum Hall states? We definitively find the answer to be: Quite poorly. In particular, we write the general expression for the spacing of resonance peaks in a simple form that explicitly displays its dependence on the conformal scaling dimensions of the systems' edge modes. This form makes transparent the general argument that the Coulomb blockade peak spacings do not provide a strongly indicative signature of the topological order of the system, since it is only weakly related to the braiding statistics. We bolster this general argument with examples for all the most physically relevant non-Abelian candidate states, demonstrating that they have Coulomb blockade doppelgangers -- candidate states at the same filling fraction with identical Coulomb blockade signatures, but dramatically different topological orders and braiding statistics.Comment: 12 pages, 1 figure; portions of this paper were formerly included in Appendix C of arXiv:0903.3108; v2: examples added, minor corrections made; v3: discussions of non-uniform filling and of hierarchical counterparts of multi-component states added, minor corrections mad

THE EFFECT OF NIGELLA SATIVA L. ON INTRACTABLE PEDIATRIC SEIZURES

Background:Despite availability and administration of numerous antiepileptic drugs (AEDs) nearly 15% of childhood epilepsy cases are resistant to treatment; in traditional medicine however Nigella sativa L. (Black seed) has been known for its anticonvulsant effects.Materials and Methods:In this double-blind clinical trial conducted on children with refractory epilepsy we administered the aqueous extract of black seed as an adjunct therapy and compared the effects with those of a placebo. The study was performed between Sep 2003 and Nov 2004. The subjects received either extract or placebo for a period of four weeks and between these two periods for two weeks they received only their pre-existing anti-epileptic drugs (AEDs).Results:The mean frequency of seizures decreased significantly during treatment with extract, (p-value =0/007).Conclusion:It can be concluded that the water extract of Nigella sativa L. has antiepileptic effects in children with refractory seizures that do not respond to known AEDS.keywords:Nigella sativa, Intractable seizures, Childre

Screening properties and phase transitions in unconventional plasmas for Ising-type quantum Hall states

Utilizing large-scale Monte-Carlo simulations, we investigate an unconventional two-component classical plasma in two dimensions which controls the behavior of the norms and overlaps of the quantum-mechanical wavefunctions of Ising-type quantum Hall states. The plasma differs fundamentally from that which is associated with the two-dimensional XY model and Abelian fractional quantum Hall states. We find that this unconventional plasma undergoes a Berezinskii-Kosterlitz-Thouless phase transition from an insulator to a metal. The parameter values corresponding to Ising-type quantum Hall states lie on the metallic side of this transition. This result verifies the required properties of the unconventional plasma used to demonstrate that Ising-type quantum Hall states possess quasiparticles with non-Abelian braiding statistics.Comment: 16 pages, 14 figures. Submitted to Physical Review