this paper proposes a flexible power electronic transformer (fpet) for the application in the micro-grids. the low frequency transformer is usually used at the point of common coupling (pcc) to connect the low voltage grid and utility network to each other. the conventional 50hz transformer results in enhanced low voltage-grid power management system during grid-connected operation. in this pap...

This paper presents studies on applying the novel weak Galerkin finite element method (WGFEM) to a two-phase model for subsurface flow, which couples the Darcy equation for pressure and a transport equation for saturation in a nonlinear manner. The coupled problem is solved in the framework of operator decomposition. Specifically, the Darcy equation is solved by theWGFEM, whereas the saturation...

Ideas that are used in the design, development, and performance of concurrency control mechanisms have been summarized. The locking, time-stamp, optimistic-based mechanisms are included. The ideas of validation in optimistic approach are presented in some detail. The degree of concurrency and classes of serializability for various algorithms have been presented. Questions that relate arrival ra...

Database systems for real-time applications must satisfy timing constraints associated with transactions, in addition to maintaining data consistency. In addition to real-time requirements, security is usually required in many applications. Multilevel security requirements introduce a new dimension to transaction processing in real-time database systems. In this paper, we argue that because of ...

In this paper, an SPH method based on the SPH–ALE formulation is used for modelling two-phase flows with large density ratios and realistic sound speeds. The SPH scheme is further improved to circumvent the tensile instability that may occur in the SPH simulations. The two-phase SPH solver is then used to model a benchmark problem of liquid impact on a rigid wall. The results are compared with ...

A method for integrated concurrency control and recovery, applicable to heterogeneous multidatabase systems is proposed1. The role of the participant in the two-phase commit protocol is laid on an entity called 2PC Agent associated with the local database system. The main importance of the method is in preserving global serializability in the presence of unilateral aborts and site failures. The...

this paper studied the mathematical method of flow with regard to two-phase boundary layer that created over the iced surface. based on experimental results, skin drag over the iced surface compared with this force that compute with slip condition. based on this results, for iced surface blasius equation solving at non-slip condition, can replace with solving the blasius equation with slip cond...

in this paper, a non-isothermal two-phase flow in the cathode gas diffusion layer (gdl) of pem fuel cell is modeled. the governing equations including energy, mass and momentum conservation equations are solved by numerical methods. also, the optimal values of the effective parameters such as the electrodes porosity, gas diffusion layer (gdl) thickness and inlet relative humidity are calculated...

flow regime in dam's bottom outlet is divided in pressurized flow and free surface flow by the gate located for discharge control. down stream tunnel involves high velocity multi component air –water flow studied by mathematical model. in this research work, we used finite volume mixture two phase flow model. because of high reynolds number, standard two equations k-e turbulence model was ...

rock chutes are natural river training structures and are efficient energy dissipaters too. from the hydraulic and environmental point of view, rock chutes have become important structures in the natural river morphology. a physical study was conducted and flow properties were measured over rough bed materials of a rock chute, which was assembled at the pitlab center of the university of pisa, ...