In this research the drying of four kinds of vegetables was investigated in a vacuum dryer. The effect of temperature on drying rate of samples at various temperatures (30, 35 and 45 °C) was studied. Six thin-layer drying models were fitted to drying data and suitable model was selected from them. Then effective moisture diffusivity and ...

<p style='text-indent:20px;'>We consider in this paper a diffusion-convection reaction equation one space dimension. The main assumptions are about the term, which is monostable, and diffusivity, changes sign once or even more than once; then, we deal with forward-backward parabolic equation. Our results concern existence of globally defined traveling waves, connect two equilibria cross b...

We present a new parameterisation for shear-driven, stratified, turbulent mixing which is pertinent to climate models, in particular the shear-driven mixing in overflows and the Equatorial Undercurrent. Critically for climate applications this parameterisation is simple enough to be implemented implicitly, which allows the parameterisation to be used with timesteps that are long compared to bot...

We study the classical model for chemotaxis, the so-called Keller-Segel model, which is a drift-diffusion equation for the cell density coupled with an elliptic equation describing the evolution of the chemoattractant. We investigate the case of small cell diffusivity and, in particular, the hyperbolic limit of the system as the diffusion coefficient goes to zero. Considering a model where the ...

This paper presents a new parameterization for shear-driven, stratified, turbulent mixing that is pertinent to climate models, in particular the shear-driven mixing in overflows and the Equatorial Undercurrent. This parameterization satisfies a critical requirement for climate applications by being simple enough to be implemented implicitly and thereby allowing the parameterization to be used w...

The “double diffusivity” model was proposed in the late seventies, and reworked in the early eighties, as a continuum counterpart to existing discrete models of diffusion corresponding to high diffusivity paths, such as grain boundaries and dislocation lines. It was later rejuvenated in the nineties to interpret experimental results on diffusion in polycrystalline and nanocrystalline specimens ...

Abstract. Reactive transport processes in natural environments often involve many ionic species. The diffusivities of species vary. Since assigning different the advection–diffusion equation leads to charge imbalance, a single diffusivity is usually used for all In this work, we apply Nernst–Planck equation, which resolves unequal an electroneutral manner, model reactive transport. To demonstra...