finding the most appropriate governing equation under different environmental conditions is the most important step for both designing sorption systems and pollutant transport modeling. in this study, the second order model based on the sorbent concentration is theoretically and experimentally investigated. a circular flume was used for the sorption of cadmium by zeolite to simulate the natural...

In this work, the solubility of nicotine extracted from tobacco leaves, found in the north of Iran, in supercritical carbon dioxide has been measured. Also the effects of pressure, temperature, extraction dynamic time, and the organic co-Solvent on the amount of nicotine extracted from tobacco leaves have been investigated. It should be stressed that in order to reduce significantly the num...

An attempt has been made to fit the derived equation on the experimental inverse relaxation curves by employing Levenberg-Marquardt’s method for nonlinear regression and calculation of the constant values involved in the equation. The relaxation curves can be classified into ordinary relaxation, mixed relaxation and inverse relaxation curves. There seems to be good concurrence between the exper...

A series of laboratory experiments was conducted to obtain high-quality data for acoustic propagation in shallow water waveguides with sloping elastic bottoms. Accurate modeling of transmission loss in these waveguides can be performed with the variable rotated parabolic equation method. Results from an earlier experiment with a flat or sloped slab of polyvinyl chloride (PVC) demonstrated the n...

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in the age of technology, it is vital to cool down different parts of a device to use it more beneficially. using nanofluids is one of the most common methods which has shown very effective results. in this paper, we have rephrased a classic equation in fluid mechanics, i.e. the falkner-skan boundary layer equation, in order to be used for nanofluid. this nonlinear equation, which was presented...

In the present work, a modified equation of state has been presented for the calculation of volumetric properties of supercritical fluids. The equation of state is van der Waals basis with temperature and density-dependent parameters. This equation of state has been applied for predicting the volumetric properties of fluids. The densities of fluids were calculated from the new equation of state...

A theoretical model is developed to consider the effect of demulsifier agent on demulsification of water-in-crude oil emulsion. A thermodynamic approach is considered to correlate the critical micelle concentration of a demulsifier to the collision frequency function in population balance equation (PBE). Based on the proposed correlation, the collision frequency function is modified to account ...

A modification of Peng-Robinson equation is described wherein in the parameter b is expressed as a linear function of temperature. The modified equation is then applied to a series of light hydrocarbons and refrigerants, and predicted values for vapor pressure, saturated vapor volume, saturated liquid volume and the heat of evaporation are compared with the corresponding experimental data. ...