An advanced meshless method for time fractional diffusion equation

Recently, because of the new developments in sustainable engineering and renewable energy, which are usually governed by a series of fractional partial differential equations (FPDEs), the numerical modelling and simulation for fractional calculus are attracting more and more attention from researchers. The current dominant numerical method for modeling FPDE is Finite Difference Method (FDM), which is based on a pre-defined grid leading to inherited issues or shortcomings including difficulty in simulation of problems with the complex problem domain and in using irregularly distributed nodes. Because of its distinguished advantages, the meshless method has good potential in simulation of FPDEs. This paper aims to develop an implicit meshless collocation technique for FPDE. The discrete system of FPDEs is obtained by using the meshless shape functions and the meshless collocation formulation. The stability and convergence of this meshless approach are investigated theoretically and numerically. The numerical examples with regular and irregular nodal distributions are used to validate and investigate accuracy and efficiency of the newly developed meshless formulation. It is concluded that the present meshless formulation is very effective for the modeling and simulation of fractional partial differential equations

A note on modular forms and generalized anomaly cancellation formulas

By studying modular invariance properties of some characteristic forms, we prove some new anomaly cancellation formulas which generalize the Han-Zhang and Han-Liu-Zhang anomaly cancellation formula

Out of plane effect on the superconductivity of Sr2-xBaxCuO3+y with Tc up to 98K

A series of new Sr2-xBaxCuO3+y (0 x 0.6) superconductors were prepared using high-pressure and high-temperature synthesis. A Rietveld refinement based on powder x-ray diffraction confirms that the superconductors crystallize in the K2NiF4-type structure of a space group I4/mmm similar to that of La2CuO4 but with partially occupied apical oxygen sites. It is found that the superconducting transition temperature Tc of this Ba substituted Sr2CuO3+y superconductor with constant carrier doping level, i.e., constant d, is controlled not only by order/disorder of apical-O atoms but also by Ba content. Tcmax =98 K is achieved in the material with x=0.6 that reaches the record value of Tc among the single-layer copper oxide superconductors, and is higher than Tc=95K of Sr2CuO3+y with optimally ordered apical-O atoms. There is Sr-site disorder in Sr2-xBaxCuO3+y which might lead to a reduction of Tc. The result indicates that another effect surpasses the disorder effect that is related either to the increased in-plane Cu-O bond length or to elongated apical-O distance due to Ba substitution with larger cation size. The present experiment demonstrates that the optimization of local geometry out of the Cu-O plane can dramatically enhance Tc in the cuprate superconductors.Comment: 23 Pages, 1 Table, 5 Figure

Fire performance of non-load-bearing light-gauge slotted steel stud walls

Experimental and numerical studies on the performance of light-gauge slotted steel stud walls subjected to fire are presented in this paper. Four full-scale light-gauge slotted steel stud walls were tested under the ISO-834 standard fire loading. Temperatures at the location of exposed surface, unexposed surface, and cross section of steel studs were measured. Spalling of the heated gypsum board during testing was investigated. The major factors affecting the behavior of this type of wall, including the height of the web, layers of gypsum boards and use of mortar on unexposed surface, were studied. Based on the test results, a three-dimensional FE model of the light-gauge slotted steel stud wall was developed using ABAQUS to analyze its fire performance. The model was validated against experiments in this study and other related test data. The FE model was employed to conduct further parametric studies. Parameters include the spalling time of heated gypsum boards, the height of the web, rows of slots, and layers of gypsum boards. The effects of these key factors on the temperatures of the exposed surface, unexposed surface and studs are discussed

Vacuum induced Berry phases in single-mode Jaynes-Cummings models

Motivated by the work [Phys. Rev. Lett. 89, 220404 (2002)] for detecting the vacuum-induced Berry phases with two-mode Jaynes-Cummings models (JCMs), we show here that, for a parameter-dependent single-mode JCM, certain atom-field states also acquire the photon-number-dependent Berry phases after the parameter slowly changed and eventually returned to its initial value. This geometric effect related to the field quantization still exists, even the filed is kept in its vacuum state. Specifically, a feasible Ramsey interference experiment with cavity quantum electrodynamics (QED) system is designed to detect the vacuum-induced Berry phase.Comment: 10 pages, 4 figures

Corrections to Tribimaximal Mixing from Nondegenerate Phases

We propose a seesaw scenario that possible corrections to the tribimaximal pattern of lepton mixing are due to the small phase splitting of the right-handed neutrino mass matrix. we show that the small deviations can be expressed analytically in terms of two splitting parameters($\delta_1$ and $\delta_2$) in the leading order. The solar mixing angle $\theta_{12}$ favors a relatively smaller value compared to zero order value ($35.3^\circ$), and the Dirac type CP phase $\delta$ chooses a nearly maximal one. The two Majorana type CP phases $\rho$ and $\sigma$ turn out to be a nearly linear dependence. Also a normal hierarchy neutrino mass spectrum is favored due to the stability of perturbation calculations.Comment: 19 pages 6 figures, Accepted by Mod. Phy. Lett.