A global existence result for the anisotropic magnetohydrodynamical systems

We study an anisotropic system arising in magnetohydrodynamics (MHD) in the whole space R^3 , in the case where there are no diffusivity in the vertical direction and only a small diffusivity in the horizontal direction (of size $\epsilon$$\alpha$ with 0 \textless{} $\alpha$ $\le$ $\alpha$0, for some $\alpha$0 \textgreater{} 0). We prove the local existence and uniqueness of a strong solution and then, using Strichartz-type estimates, we prove that this solution globally exists in time for large initial data, when the rotation is fast enough

Dispersive effects of weakly compressible and fast rotating inviscid fluids

We consider a system describing the motion of an isentropic, inviscid, weakly com-pressible, fast rotating fluid in the whole space R^3 , with initial data belonging to H^s(R^3) , s \textgreater{} 5/2. We prove that the system admits a unique local strong solution in L^$\infty$([0, T ]; H^s(R^3)) , where T is independent of the Rossby and Mach numbers. Moreover, using Strichartz-type estimates, we prove that the solution is almost global, i.e. its lifespan is of the order of $\epsilon$^(--$\alpha$) , $\alpha$ \textgreater{} 0, without any smallness assumption on the initial data (the initial data can even go to infinity in some sense), provided that the rotation is fast enough.Comment: Revised versio

Improving performance of far users in cognitive radio: Exploiting NOMA and wireless power transfer

In this paper, we examine non-orthogonal multiple access (NOMA) and relay selection strategy to benefit extra advantage from traditional cognitive radio (CR) relaying systems. The most important requirement to prolong lifetime of such network is employing energy harvesting in the relay to address network with limited power constraint. In particular, we study such energy harvesting CR-NOMA using amplify-and-forward (AF) scheme to improve performance far NOMA users. To further address such problem, two schemes are investigated in term of number of selected relays. To further examine system performance, the outage performance needs to be studied for such wireless powered CR-NOMA network over Rayleigh channels. The accurate expressions for the outage probability are derived to perform outage comparison of primary network and secondary network. The analytical results show clearly that position of these nodes, transmit signal to noise ratio (SNR) and power allocation coefficients result in varying outage performance. As main observation, performance gap between primary and secondary destination is decided by both power allocation factors and selection mode of single relay or multiple relays. Numerical studies were conducted to verify our derivations.Web of Science1211art. no. 220

Coarse-grained model for spring friction study of micron-scale iron by smoothed particle hydrodynamics

The paper constructs a coarse-grained model to investigate dry sliding friction of the body-centered-cubic Fe micron-scale system by smoothed particle hydrodynamics simulations and examines influences of the spring force on the characters of friction. The N_atom = 864 \times 10^12 atoms Fe system is coarse-grained into the two different simple-cubic particle systems, one of 432000 and the other of 16000 particles. From the detection of stick-slip motion, friction coefficient, dependence of friction coefficient on isotropy or anisotropy of the spring force and externally applied normal load, we find that the coarse-grained model is a reasonable modeling process for study of friction of the Fe system and the anisotropic behavior presents better friction of the system than the isotropic one