a linear low density polyethylene (lldpe) production process, including two- fuidized bed reactors in series (fbrs) and other process equipment, was completely simulated by aspen polymer plus software. fluidized bed reactors were considered as continuous stirred tank reactors (cstr consisted of polymer and gas phases). poly-srk and nrtl-rk equations of state were used to describe polymer and no...

In design of anaerobic bioreactor, rate equation is commonly used. Mathematical model was developed at steady state condition, to project concentration of gaseous substrate and product in biological oxidation of carbon monoxide with water to produce hydrogen and carbon dioxide. The concept of bioconversion was based on transport of CO from gas phase to liquid phase, as the CO consumption was in...

This study investigates the role of nitrogen (N2) in transmucosal gas exchange of the middle ear (ME). We used an experimental rat model to measure gas volume variations in the ME cavity at constant pressure. We disturbed the steady-state gas composition with either air or N2 to measure resulting changes in volume at ambient pressure. Changes in gas volume over time could be characterized by th...

This paper describes a technique to determine the linear wellposedness of a general class of vector elliptic problems that include a steady interface, to be determined as part of the problem, that separates two subdomains. The interface satisfies mixed Dirichlet and Neumann conditions. We consider “2+2” models, meaning two independent variables respectively on each subdomain. The governing equa...

objective(s) the purpose of this study was assessment of the influence of acute manic phase on the steady state pharmacokinetics of valproic acid (vpa) in bipolar patients in comparison with those of epileptic patients. materials and methods ninteen acutely manic and 25 epileptic patients who fulfilled inclusion and exclusion criteria were entered in this prospective study. blood samples were c...

A general framework is presented for accurately and efficiently estimating the phenomenological pressure-dependent rate coefficients for reaction networks of arbitrary size and complexity using only high-pressure-limit information. Two aspects of this framework are discussed in detail. First, two methods of estimating the density of states of the species in the network are presented, including ...

This paper considers the modeling and control of a tubular fixed bed reactor with recycle stream for dimethyl ether (DME) production. For simulation purposes, a pseudo homogeneous model has been developed. By reactor simulation under steady state condition, effects of parameters such as feed rate, pressure and shell temperature are investigated. Using the steady state model, an optimizer that m...

gas reservoirs with low permeability (k