Islamic Azad UniversitySouth Tehran Branch

Tehrān, Iran

Islamic Azad UniversitySouth Tehran Branch

Tehrān, Iran
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Rahimi E.,Islamic Azad UniversitySouth Tehran Branch | Mohaghegh N.,Sharif University of Technology
Environmental Science and Pollution Research | Year: 2017

The application of a hybrid Cu(tpa).GO (Cu(tpa) copper terephthalate metal organic framework, GO graphene oxide) composite as a new adsorbent for the removal of toxic metal ions was reported. New hybrid nanocomposite with excellent dispersibility and stability was successfully fabricated by the simple and effective ultrasonication method. The synthesized composite was characterized by scanning electron microscopy (SEM), UV-Vis and Fourier-transform infrared (FT-IR) techniques. The characterization results concluded that the binding mechanism of the Cu(tpa) and GO was related to both π−π packing and hydrogen bonding. For scrutinizing the sorption activity, the prepared adsorbents were assessed for the removal of Mn2+, Cu2+, Zn2+, Cd2+, Pb2+ and Fe3+ metal ions from aqueous synthetic solution and also acid mine drainage (AMD) wastewater. The sorption experiments demonstrated that the removal efficiency was significantly improved by modified hybrid Cu(tpa).GO composite, owing to the significant number of active binding sites and unique structure formed based on π-conjugated networks. Also, it was shown that the adsorption reaction was mainly attributed to the chemical interactions between metal ions and the surface functional groups. Moreover, kinetic and adsorption studies clarified that the adsorption process onto the Cu(tpa).GO follows a pseudo-second-order kinetics and fits the Langmuir and Freundlich adsorption models. Holistically, the results of this research represent that applying Cu(tpa).GO can be remarked as an effective adsorbent with high possibility at conventional water treatment. © 2017 Springer-Verlag GmbH Germany


Noorossana R.,Islamic Azad UniversitySouth Tehran Branch | Fatemi S.A.,Islamic Azad UniversitySouth Tehran Branch | Zerehsaz Y.,Islamic Azad UniversitySouth Tehran Branch
International Journal of Advanced Manufacturing Technology | Year: 2014

In many practical situations, quality of a process or product can well be characterized by a relation between a response variable and one or more explanatory variables. This functional relationship which is commonly referred to as profile has been addressed by many researchers for the case of fixed explanatory variable. However, there are some situations where this assumption may not hold. In this paper, we try to investigate the effect of random explanatory variable on phase II monitoring of simple linear profiles. Average run length criterion is used to evaluate both the in-control and out-of-control performances of the control schemes commonly considered for phase II profile monitoring. The charting performance of the EWMA-3 control scheme has been improved using a novel technique. © 2014, Springer-Verlag London.


Noorossana R.,Islamic Azad UniversitySouth Tehran Branch | Zerehsaz Y.,Islamic Azad UniversitySouth Tehran Branch
International Journal of Advanced Manufacturing Technology | Year: 2015

In this paper, we study the effect of classical additive measurement error model on the most commonly used control charts for monitoring simple linear profiles with random explanatory variable. We showed that the in-control and out-of-control performances of these methods are significantly affected when measurement error is present in the explanatory variable. The average run length criterion is applied to represent the performance of the methods. For instance, we can clearly see that even a small amount of measurement error introduced in the explanatory variable of a profile can increase the false alarm rate about 55 %. With the same negligible amount of error, the out-of-control average run length of the exponentially weighted moving average chart (EWMA)-3 method in detecting a moderate-size shift in the slope parameter increases 15 %. Two different strategies on the basis of control limit modification have been proposed to compensate for the undesired effect of measurement error. Results indicate that the proposed strategies substantially offset the poor performances of the control charts resulted from the presence of measurement error. © 2015, Springer-Verlag London.

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