Observational constraints on the extended Chaplygin gas inflation     

E. O. Kahya  B. Pourhassan 《Astrophysics and Space Science》2014,353(2):677-682

In this paper, we study extended Chaplygin gas as a candidate for inflation and predict the values of gas parameters for a physically viable cosmological model. The extended Chaplygin gas which proposed recently has n+2 free parameters. When n=1, there are three parameters which are corresponding to modified Chaplygin gas. Here we focus on the second order equation of state where n=2, so we have generally four free parameters. Under some assumptions, we reduced free parameters of the model to the only one parameter and try to fix it using the dimensionless age parameter. Also we check validity of our calculations using recent observations of BICEP2.  相似文献   

FRW bulk viscous cosmology with modified cosmic Chaplygin gas     

H. Saadat  B. Pourhassan 《Astrophysics and Space Science》2013,344(1):237-241

In this paper we study FRW bulk viscous cosmology in presence of modified cosmic Chaplygin gas. We obtain generalized Friedmann equations due to bulk viscosity and modified cosmic Chaplygin gas. Then, we calculate time-dependent energy density and discuss Hubble expansion parameter.  相似文献   

An effective quintessence field with a power-law potential     

M. Khurshudyan  B. Pourhassan  R. Myrzakulov  S. Chattopadhyay 《Astrophysics and Space Science》2015,356(2):383-391

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Central Composite Design Optimization of Biological Dye Removal in the Presence of Macroalgae Chara sp.     

Ali R. Khataee  Gholamreza Dehghan  Elahe Ebadi  Minoo Pourhassan 《洁净——土壤、空气、水》2010,38(8):750-757

Response surface methodology (RSM) was employed to investigate the effects of different operational parameters on the biological decolorization of a dye solution containing malachite green (MG) in the presence of macroalgae Chara sp. The investigated variables were the initial pH, initial dye concentration, algae amount, and reaction time. Central composite design (CCD) was used for the optimization of biological decolorization process. Predicted values were found to be in good agreement with experimental values (R² = 0.982 and Adj‐R² = 0.966), which indicated suitability of the employed model and the success of RSM. The results of optimization predicted by the model showed that maximum decolorization efficiency was achieved at the optimum condition of the initial pH 6.8, initial dye concentration 9.7 mg/L, algae amount 3.9 g, and reaction time 75 min. UV–VIS spectra and FT‐IR analysis showed degradation of MG.  相似文献   

FRW bulk viscous cosmology with modified Chaplygin gas in flat space     

H. Saadat  B. Pourhassan 《Astrophysics and Space Science》2013,343(2):783-786

In this paper we study FRW bulk viscous cosmology in presence of modified Chaplygin gas. We write modified Friedmann equations due to bulk viscosity and Chaplygin gas and obtain time-dependent energy density for the special case of flat space.  相似文献