University of Tabriz

About: University of Tabriz is a education organization based out in Tabriz, Iran. It is known for research contribution in the topics: Population & Nanocomposite. The organization has 12141 authors who have published 20976 publications receiving 313982 citations.

Imperialist competitive algorithm for solving systems of nonlinear equations

Abstract: Solving systems of nonlinear equations is a relatively complicated problem in which arise a diverse range of sciences. There are a number of different approaches that have been proposed. In this paper, we employ the imperialist competitive algorithm (ICA) for solving systems of nonlinear equations. Some well-known problems are presented to demonstrate the efficiency of this new robust optimization method in comparison to other known methods.

Liquid phase microextraction of pesticides: a review on current methods

Abstract: Liquid phase microextraction (LPME) enables analytes to be extracted with a few microliters of an organic solvent. LPME is a technique for sample preparation that is extremely simple, affordable and virtually a solvent-free. It can provide a high degree of selectivity and enrichment by eliminating carry-over between single runs. A variety of solvents are known for the extraction of the various analytes. These features have led to the development of techniques such as single drop microextraction, hollow fiber LPME, dispersive liquid-liquid microextraction, and others. LPME techniques have been applied to the analysis of pharmaceuticals, food, beverages, and pesticides. This review covers the history of LPME methods, and then gives a comprehensive collection of their application to the preconcentration and determination of pesticides in various matrices. Specific sections cover (a) sample treatment techniques in general, (b) single-drop microextraction, (c) extraction based on the use of ionic liquids, (d) solidified floating organic drop microextraction, and various other techniques. Contains 149 references.

Effects of TiO2 nanoparticles on the aquatic plant Spirodela polyrrhiza: Evaluation of growth parameters, pigment contents and antioxidant enzyme activities.

Abstract: Plants are essential components of all ecosystems and play a critical role in environmental fate of nanoparticles. However, the toxicological impacts of nanoparticles on plants are not well documented. Titanium dioxide nanoparticles (TiO2-NPs) are produced worldwide in large quantities for a wide range of purposes. In the present study, the uptake of TiO2-NPs by the aquatic plant Spirodela polyrrhiza and the consequent effects on the plant were evaluated. Initially, structural and morphological characteristics of the used TiO2-NPs were determined using XRD, SEM, TEM and BET techniques. As a result, an anatase structure with the average crystalline size of 8nm was confirmed for the synthesized TiO2-NPs. Subsequently, entrance of TiO2-NPS to plant roots was verified by fluorescence microscopic images. Activity of a number of antioxidant enzymes, as well as, changes in growth parameters and photosynthetic pigment contents as physiological indices were assessed to investigate the effects of TiO2-NPs on S. polyrrhiza. The increasing concentration of TiO2-NPs led to the significant decrease in all of the growth parameters and changes in antioxidant enzyme activities. The activity of superoxide dismutase enhanced significantly by the increasing concentration of TiO2-NPs. Enhancement of superoxide dismutase activity could be explained as promoting antioxidant system to scavenging the reactive oxygen species. In contrast, the activity of peroxidase was notably decreased in the treated plants. Reduced peroxidase activity could be attributed to either direct effect of these particles on the molecular structure of the enzyme or plant defense system damage due to reactive oxygen species.

A Novel High-Performance Supercapacitor based on Chitosan/Graphene Oxide-MWCNT/Polyaniline

Abstract: Chitosan/Graphene Oxide-MWCNT/polyaniline (CS/GM/PANI) ternary nanocomposite has been synthesized via in situ polymerization of aniline in the presence of CS/GM. The Morphology of nanocomposites was studied by Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, as well as X-ray photoelectron spectroscopy (XPS). Furthermore, the supercapacitive behavior of the CS-based samples was investigated using cyclic voltammetry (CV), galvanostatic charge-discharge (CD) and electrochemical impedance spectroscopy (EIS) techniques in 0.5M Na2SO4. It is found that the CS/GM/PANI nanocomposite displays much higher specific capacitance along with better cycle stability than those of CS and CS/GM. The specific capacitance of 609.2Fg-1 (48.5mFcm-2) was obtained for the CS/GM/PANI at a scan rate of 10mVs-1. In addition, the synthesized nanocomposite retained 96% of the initial capacitance after 500 cycles of charge-discharge at a current density of 5Ag-1. The improvement in the supercapacitive behavior of CS/GM/PANI may be attributed to the porous structure and pseudocapacitive mechanism of charge-storage.