in the present study, a heterogeneous and homogeneous gas flow dispersion model for simulation and optimization of a large-scale catalytic slurry reactor for the direct synthesis of dimethyl ether (dme) from synthesis gas (syngas) and co2, using a churn-turbulent regime was developed. in the heterogeneous flow model, the gas phase was distributed into two bubble phases including small and large...

The rapid depletion of oil and the environmental impact of combustion has motivated the search for clean combustion technologies. Fluidised bed combustion (FBC) technology works by suspending a fuel over a fast air inlet whilst sustaining the required temperatures. Using biomass or a mixture of coal/biomass as the fuel, FBC provides a low-carbon combustion technology whilst operating at low tem...

Region-based level set segmentation is a paradigm for the automatic segmentation of brain tumor image. Unfortunately, region-based segmentation, which is relied on the intensity difference of different regions, has been of limited used in presence of complex background. Algorithm based on calculating the variational energy of the Chan-Vese model without the length. The multiphase level set form...

Heterogeneous diffusion processes occur in many different fields such as transport in living cells or diffusion in porous media. A characterization of the transport parameters of such processes can be achieved by ensemble-based methods, such as pulsed field gradient nuclear magnetic resonance (PFG NMR), or by trajectory-based methods obtained from single-particle tracking (SPT) experiments. In ...

introduction: the medical applications of ultrasound on human brain are highly limited by the phase and amplitude aberrations induced by the heterogeneities of the skull. however, it has been shown that time reversing coupled with amplitude compensation can overcome these aberrations. in this work, a model for 2d simulation of the time reversal mirror technique is proposed to study the possibil...

In o_shore petroleum engineering, the multiphase production technique has become a standard method for the exploitation of marginal fields. The multiphase production technology consists in conveying untreated wellhead e_uent through a single pipeline either to an existing processing platform or to onshore processing facilities. Transient phenomena can be caused by changes in the inlet flow-rate...

We consider a hyperbolic system of three conservation laws in one space variable. The system is a model for fluid flow allowing phase transitions; in this case the state variables are the specific volume, the velocity and the mass density fraction of the vapor in the fluid. For a class of initial data having large total variation we prove the global existence of solutions to the Cauchy problem....

Time-resolved experiments with more than one period of incoherent time evolution are becoming increasingly accessible. When applied to a two-level system, these experiments separate homogeneous and heterogeneous contributions to kinetic dispersion, i.e., to nonexponential relaxation. Here, the theory of two-dimensional (2D) multiple population-period transient spectroscopy (MUPPETS) is extended...

Two-dimensional (2D) materials offer numerous advantages for electrochemical energy storage and conversion due to fast charge transfer kinetics, highly accessible surface area, and tunable electronic and optical properties. Stacking of 2D materials generates heterogeneous interfaces that can modify native chemical and physical material properties. Here, we demonstrate that local strain at a car...

A 2D Euler-Euler multiphase computational fluid dynamics (CFD) model in conjunction with the kinetic theory of granular flow (KTGF) was applied to describe biomass pyrolysis a spouted bed reactor. The primary interest this work development CFD hydrodynamic reactor coupled for prediction product yields (gas, bio-oil, and char). is based on three parallel reactions formation products secondary re...