A kinetic theory is formulated for the velocity of a step edge in epitaxial growth. The formulation involves kinetic, mean-field equations for the density of kinks and "edge adatoms" along the step edge. Equilibrium and kinetic steady states, corresponding to zero and nonzero deposition flux, respectively, are derived for a periodic sequence of step edges. The theoretical results are compared t...

a mathematical model for commercial naphtha catalytic reformer of tehran refinery was developed. this model includes three sequencing fixed beds of pt/al2o3 catalyst at the steady state condition using detailed kinetic scheme involving 26 pseudo-components connected by a network of 47 reactions, in the range of c6 to c9 hydrocarbons. the reaction network consisted dehydrogenation, hydrogenation...

Modeling and simulation of Polyhydroxybutyrate (PHB) production by Protomonas extorquens in fed-batch culture were conducted in this research. The fed-batch model, developed for this process, employed a kinetic model proposed by other researchers. Several kinetic models were investigated to choose the best model. The criterion for this selection was goodness of fit (δ2). Haldane kinetic model w...

the kinetic of fischer-tropsch synthesis over a co-precipitated fe-ce catalyst was investigated in a fixed bed micro reactor. experimental conditions were varied as follow: reaction pressure 1-15bar, h¬¬¬2/co feed ratio of 1-3 and space velocity of 3600-5400 h-1 at the temperature range of 270-310°c. 4 models according to the langmuir-hinshelwood-hougen-watson (lhhw) type rate equation were der...

the removal of uranium and any other heavy metals from wastewater might be achieved via several chemical or physical treatment techniques. biosorption process has been considered as a potential alternative way to remove contaminants from industrial effluents. moreover the surface of biosorbent was characterized by sem. the biosorption characteristics of uranium (vi) on pretreated a. niger were ...

in this paper, a new model based on kinetic theory of gases and longitude oscillations of metallic nanocluster on single carbon nanotube (cnt) in addition to phononvibrations of cnt on substrate is presented to describe the growth mechanism of ultra-long cnt in chemical vapor deposition (cvd).interaction between cnt and catalyst is investigated by lennard-jones potential. simulations demonstrat...

Mathematical models for wastewater treatment ponds and photobioreactors are increasing in popularity for design of new systems and for improving understanding of the complex biokinetic processes occurring inside. However, models in these systems are still not a common practice because the complex bioprocesses and hydrodynamics make them very difficult to translate into accurate mathematic descr...

industrial wastewater included the dyes one of the important sources of environmental pollution that founded in loom wastewater which are harmful for human health and environment. therefore, the purpose of this research was investigated removal of rb5 dye from aqueous solution by using of adsorption onto activated red mud as an cheap adsorbent. this research was experimental- laboratorial study...