Potential for non-combustible nicotine products to reduce socioeconomic inequalities in smoking: a systematic review and synthesis of best available evidence

While some experts have emphasised the potential for e-cigarettes to facilitate cessation among smokers with low socioeconomic status (SES), there is limited evidence of their likely equity impact. We assessed the potential for electronic cigarettes and other non-combustible nicotine-containing products (NCNPs) to reduce inequalities in smoking by systematically reviewing evidence on their use by SES in countries at stage IV of the cigarette epidemic

MFIX documentation numerical technique

MFIX (Multiphase Flow with Interphase eXchanges) is a general-purpose hydrodynamic model for describing chemical reactions and heat transfer in dense or dilute fluid-solids flows, which typically occur in energy conversion and chemical processing reactors. The calculations give time-dependent information on pressure, temperature, composition, and velocity distributions in the reactors. The theoretical basis of the calculations is described in the MFIX Theory Guide. Installation of the code, setting up of a run, and post-processing of results are described in MFIX User`s manual. Work was started in April 1996 to increase the execution speed and accuracy of the code, which has resulted in MFIX 2.0. To improve the speed of the code the old algorithm was replaced by a more implicit algorithm. In different test cases conducted the new version runs 3 to 30 times faster than the old version. To increase the accuracy of the computations, second order accurate discretization schemes were included in MFIX 2.0. Bubbling fluidized bed simulations conducted with a second order scheme show that the predicted bubble shape is rounded, unlike the (unphysical) pointed shape predicted by the first order upwind scheme. This report describes the numerical technique used in MFIX 2.0

MFIX documentation: User`s manual

MFIX (Multiphase Flow with Interphase exchanges) is a general-purpose hydro-dynamic model for describing chemical reactions and heat transfer in dense or dilute fluid-solids flows, which typically occur in energy conversion and chemical processing reactors. MFIX calculations give time-dependent information on pressure, temperature, composition, and velocity distributions in the reactors. The theoretical basis of the calculations is described in the MFIX Theory Guide. This report, which is the MFIX User`s Manual, gives an overview of the numerical technique, and describes how to install the MFIX code and post-processing codes, set up data files and run MFIX, graphically analyze MFIX results, and retrieve data from the output files. Two tutorial problems that highlight various features of MFIX are also discussed

Higher order discretization methods for the numerical simulation of fluidized beds

Numerical models of fluidized beds based on the multiphase mass and momentum balance equations for gas and solids phases continue to be developed by several groups of researchers around the world. It has been demonstrated that the same set of equations is able to describe a wide range of fluidization conditions, ranging from bubbling to circulating fluidized beds. The results of bubbling bed simulations, plots of void fraction distribution, show the formation and propagation of high void fraction regions, called bubbles. This study shows that these problems are numerical artifacts of using first order accurate discretization schemes and coarse grids and are not due to a fundamental difficulty with the theory. This study was motivated by the observation that the shape of the gas hold up profile described by Sokolichin et al. is similar to that of the shape of bubbles in a fluidized bed. Second-order accurate discretization schemes were included in a multiphase flow model of fluidized beds called MFIX. It is shown here that the bubble shape predicted with a second order accurate scheme is rounded. The simulations were conducted for long durations (5 s) and the results did not show the fountain formation at the bed surface. It appears that the fountain formation is caused by coarse grids and low physical viscosity of the solids phase

METC Gasifier Advanced Simulation (MGAS) model

Morgantown Energy Technology Center is developing an advanced moving-bed gasifier, which is the centerpiece of the Integrated Gasifier Combined-Cycle (IGCC) system, with the features of good efficiency, low cost, and minimal environmental impact. A mathematical model of the gasifier, the METC-Gasifier Advanced Simulation (MGAS) model, has been developed for the analysis and design of advanced gasifiers and other moving-bed gasifiers. This report contains the technical and the user manuals of the MGAS model. The MGAS model can describe the transient operation of coflow, counterflow, or fixed-bed gasifiers. It is a one-dimensional model and can simulate the addition and withdrawal of gas and solids at multiple locations in the bed, a feature essential for simulating beds with recycle. The model describes the reactor in terms of a gas phase and a solids (coal or char) phase. These phases may exist at different temperatures. The model considers several combustion, gasification, and initial stage reactions. The model consists of a set of mass balances for 14 gas species and three coal (pseudo-) species and energy balances for the gas and the solids phases. The resulting partial differential equations are solved using a finite difference technique