Showing 3 results for Fardi
A. Fraji, Gh. Asadollahfardi, A. Shevidi,
Volume 11, Issue 4 (Transaction A: December 2013)
Abstract
Secondary clarifiers with large areas are widely applied in wastewater treatment plants. A pilot study was conducted to
examine the possibility of applying one and two-stage inclined tube settlers instead of conventional secondary clarifiers. Tube
diameter in the first stage of the two-stage settler was wide as the conventional ones, but in the second stage, it was narrow to
improve the efficiency. The results indicated that in short detention times, the tube settler was more effective in shorter
detention time than the conventional secondary sedimentation basin, and its effluent of TSS and turbidity was acceptable to
discharge into the surface waters. The average removal of TSS, BOD5, and COD, in a 20-minute detention time in the tubes, in
the one-stage tube settler pilot plants was 97.6%, 96.4%, and 96.36%, respectively, while in the conventional secondary
sedimentation basin was 98.2%, 99%, and 98.6%, respectively. There was a good agreement between theoretical analyses and
experimental results of the pilot plant. Two-stage tube settlers in the series could improve hydraulic condition and removal
efficiency of TSS, in comparison with the one-stage tube settler. The average TSS removal, in shorter detention times than that
the one-stage, was 97.8%.
E. Lotfi, S. Delfan, A. Hamidi, H. Shahir, Gh. Fardi,
Volume 12, Issue 1 (Transaction B: Geotechnical Engineering, January 2014)
Abstract
In saturated soils, heating induces thermal expansion of both grains and the pore fluid. Lower thermal expansion
coefficient of aggregates results in the increase of pore pressure and reduction of the effective stress besides subsequent
volume changes due to the dissipation of pore pressure and heat transfer. Dissipation of thermally induced pore pressure with
time is a coupled thermo-hydro-mechanical (THM) phenomenon, involving gradients of pore pressure and temperature,
hydraulic and thermal flows within the mass of soil and changes in the mechanical properties with temperature. The objective
of this paper is presentation of a numerical method to determine the effect of temperature on consolidation of clays. In this
regard, the finite element code, PISA is used for one dimensional THM analysis of porous media. The analysis performed
using both linear elastic and elastoplastic Cam clay models. Modified Cam clay model was applied in elastoplastic analysis.
Variation of temperature, displacements and pore pressure determined with time and compared with numerical solutions of
other researchers. Also it was indicated that implementation of coupled THM analysis yields better results for displacements
compared to the hydro mechanical (HM) one. Application of elastoplastic constitutive model instead of linear elastic one
indicated that preconsolidation pressure has an important effect on results of analysis.
Gholamreza Asadollahfardi,
Volume 14, Issue 4 (Transaction A: Civil Engineering 2016)
Abstract
This paper presents a numerical model based on the explicit finite difference method for contaminant transport under electrokinetic remediation process. The effect of adsorption, precipitation and water auto-ionization reactions were considered to set of algebraic equations. Also the effect of electrolysis reaction in anode and cathode cells was considered with appropriate boundary conditions. The model predictions are compared with experimental results of electrokinetic lead removal from kaolinite in the literature. The coefficient of determination and index of agreement between the lead concentration of experimental result and model prediction was 0.974 and 0.884, respectively. The coefficient of determination and index of agreement between the pH value of the experiment and the pH prediction was 0.975 and 0.976, respectively
