A variety of processes of crystal growth proceeds via the gas phase. A short comparative overview on gas phase transports is given here. However, in the main we deal with the concept of Chemical Vapor Transport Reactions [1, 2]. The term “Chemical Vapor Transport” (CVT) summarizes heterogeneous reactions which show one shared feature: a condensed phase, typically a solid, has an insufficient pr...

The steady–state operation of the autothermal reformer is simulated as two reactors in series by means of a detailed mathematical model. An input-output model is selected to describe the upper combustion chamber. The possible occurrence of homogeneous steam reforming and watergas-shift (WGS) reactions is considered. The catalyst bed is represented through a one-dimensional heterogeneous model, ...

Anodes for Li-ion batteries are primarily carbon-based due to their low cost and long cycle life. However, improvements to the Li capacity of carbon anodes, LiC6 in particular, are necessary to obtain a larger energy density. Stateof-the-art light-metal hydrides for hydrogen storage applications often contain Li and involve reactions requiring Li transport, and light-metal ionic hydrides are ca...

effective methodologies for efficient preparation of semicarbazones from aldehydes or ketones via milling and the subsequent regeneration of the parent carbonyls by gaseous nitrogen dioxide are described under solid-solid and gas-solid reaction conditions, respectively. these methods are fast, simple and environmentally benign which do not require the use of any auxiliaries such as catalysts or...

In this paper, a mathematical model is developed to calculate the conversion and the residence time reaction for plug flow and mixed flow in the reactors filled with cylin-drical particles using the shrinking core model. In this modeling, the size of the particles is un-chamged during the reaction. Also, the reaction rate is controlled by the gas layer resistance, the ash layer resistance, and ...

Alkali metal doping is essential to achieve highly efficient energy conversion in Cu(In,Ga)Se2 (CIGSe) solar cells. Doping is normally achieved through solid state reactions, but recent observations of gas-phase alkali transport in the kesterite sulfide (Cu2ZnSnS4) system (re)open the way to a novel gas-phase doping strategy. However, the current understanding of gas-phase alkali transport is v...

We present the detection of ro-vibrational absorption lines of the deformation mode of gaseous CH 4 toward the massive protostars W 33A, and NGC 7538 : IRS9, using the SWS spectrometer on board of the Infrared Space Observatory. The observed lines indicate that the CH 4 gas is warm (T ∼ 90 K), and has a low abundance (∼ 4 10 −7). The CH 4 ice in these lines of sight is embedded in a polar matri...

here two atoms recombine thus forming a diatomic molecule that can be either chemisorbed or reflected in the gas-phase in a given internal energy state. Reactions (1)-(2) are very often the rate determining step of complex heterogeneous systems of interest in different branches of industrial and technological applications, as for example in the ammonia synthesis, hydrocarbon production, chemica...

Ni6(N2H4)6(SO4)4(OH)2(H2O)8](SO4)(H2O)10 complex was prepared according to literature report. The reaction between aforementioned complex via sodium alkoxides as a reactants, were carried out in the solid state. The [Ni6(N2H4)6(SO4)4(OH)2(H2O)8](SO4)(H2O)10 undergoes an intramolecular two electrons oxidation-reduction reaction at room temperature and metallic nickel nanoparticles (Ni1-Ni5) was ...

n this work, computational fluid dynamics of the flow behavior in a cold flow of fluidized bed is studied. An improved finite volume based finite element method has been introduced to solve the two-phase gas/solid flow hydrodynamic equations. This method uses a collocated grid, where all variables are located at the nodal points. The fluid dynamic model for gas/solid two-phase flow is based on ...