sorption reactions in many heterogeneous systems are important. adsorption is a time dependent process and knowing the adsorption rate is essential for designing, evaluating and recovering the adsorbents. at the present study, an ammonium adsorption kinetic experiment by some soils series of golestan provice, which is varying in mineralogical and textural properties was conducted using solution...

We consider two simple conservative systems of parabolic-elliptic and parabolic-degenerate type arising in modeling chemotaxis and angiogenesis. Both systems share the same property that when the L d 2 norm of initial data is small enough, where d ≥ 2 is the space dimension, then there is a global (in time) weak solution that stays in all the L spaces with max{1; d 2 − 1} ≤ p < ∞. This result i...

In this paper we prove results relating the (parabolic) non-tangential maximum operator and appropriate square functions in Lp for solutions to general second order, symmetric and strongly elliptic parabolic systems with real valued and constant coefficients in the setting of a class of time-varying, non-smooth infinite cylinders Ω. In particular we prove a global as well as a local and scale i...

Implicit schemes are popular methods for the integration of time dependent PDEs such as hyperbolic and parabolic PDEs. However the necessity to solve corresponding linear systems at each time step constitutes a complexity bottleneck in their application to PDEs with rough coefficients. We present a generalization of gamblets introduced in [51] enabling the resolution of these implicit systems i...

Several systems of evolutionary partial differential equations may contain stiff terms, which require an implicit treatment. Typical examples are hyperbolic systems with stiff hyperbolic or parabolic relaxation and kinetic equations in regimes close to fluid dynamic limit. In the hyperbolic-to-hyperbolic relaxation (HSHR) a natural treatment consists in adopting implicit-explicit (IMEX) schemes...

A new kind of backward stochastic differential equations (in short BSDE), where the solution is a pair of processes adapted to the past of the driving Brownian motion, has been introduced by the authors in [63. It was then shown in a series of papers by the second and both authors (see [8, 7, 9, 103), that this kind of backward SDEs gives a probabilistic representation for the solution of a lar...

We introduce and study parallel space-time domain decomposition methods for solving deterministic and stochastic parabolic equations. Traditional parallel algorithms solve parabolic problems time step by time step. The parallelism is restricted to each time step, and the algorithms are purely sequential in time. In this paper, we develop some overlapping Schwarz methods whose subdomains cover b...

Parabolic concentrator mirrors are an important component of many solar energy systems, particularly solar mirror collectors. Precision parabolic mirrors are expensive to fabricate and to transport. Here, a new concept for designing and fabricating precision parabolic mirrors is presented. The mirror is formed from a thin flat very flexible metal sheet with a highly reflective surface. Attached...

In the present work the effect of Cu-Water nanofluid, as heat transfer fluid, on the performance of a parabolic solar collector was studied numerically. The temperature field, thermal efficiency, mean-outlet temperatures have been evaluated and compared for the conventional parabolic collectors and nanofluid based collectors. Further, the effect of various parameters such as fluid velocity, vol...