Islamic Azad University

About: Islamic Azad University is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Population & Catalysis. The organization has 83635 authors who have published 113437 publications receiving 1275049 citations. The organization is also known as: Azad University.

Adsorption Properties of Tetracycline onto Graphene Oxide: Equilibrium, Kinetic and Thermodynamic Studies

Abstract: Graphene oxide (GO) nanoparticle is a high potential effective absorbent. Tetracycline (TC) is a broad-spectrum antibiotic produced, indicated for use against many bacterial infections. In the present research, a systematic study of the adsorption and release process of tetracycline on GO was performed by varying pH, sorption time and temperature. The results of our studies showed that tetracycline strongly loads on the GO surface via π–π interaction and cation–π bonding. Investigation of TC adsorption kinetics showed that the equilibrium was reached within 15 min following the pseudo-second-order model with observed rate constants of k2 = 0.2742–0.5362 g/mg min (at different temperatures). The sorption data has interpreted by the Langmuir model with the maximum adsorption of 323 mg/g (298 K). The mean energy of adsorption was determined 1.83 kJ/mol (298 K) based on the Dubinin–Radushkevich (D–R) adsorption isotherm. Moreover, the thermodynamic parameters such as ΔH°, ΔS° and ΔG° values for the adsorption were estimated which indicated the endothermic and spontaneous nature of the sorption process. The electrochemistry approved an ideal reaction for the adsorption under electrodic process. Simulation of GO and TC was done by LAMMPS. Force studies in z direction showed that tetracycline comes close to GO sheet by C8 direction. Then it goes far and turns and again comes close from amine group to the GO sheet.

The effect of velocity and dimension of solid nanoparticles on heat transfer in non-Newtonian nanofluid

Abstract: In this investigation, the behavior of non-Newtonian nanofluid hydrodynamic and heat transfer are simulated. In this study, we numerically simulated a laminar forced non-Newtonian nanofluid flow containing a 0.5 wt% carboxy methyl cellulose (CMC) solutionin water as the base fluid with alumina at volume fractions of 0.5 and 1.5 as the solid nanoparticle. Numerical solution was modelled in Cartesian coordinate system in a two-dimensional microchannel in Reynolds number range of 10≤Re≤1000. The analyzed geometrical space here was a rectangular part of whose upper and bottom walls was influenced by a constant temperature. The effect of volume fraction of the nanoparticles, Reynolds number and non-Newtonian nanofluids was studied. In this research, the changes pressure drop, the Nusselt number, dimensionless temperature and heat transfer coefficient, caused by the motion of non-Newtonian nanofluids are described. The results indicated that the increase of the volume fraction of the solid nanoparticles and a reduction in the diameter of the nanoparticles would improve heat transfer which is more significant in Reynolds number. The results of the introduced parameters in the form of graphs drawing and for different parameters are compared.

Application of eco-friendly products as corrosion inhibitors for metals in acid pickling processes - A review

Abstract: Acid pickling is one of the industrial processes used for removal of scales. The main acids abundantly used in industries are HCl and H2SO4. One of the severe problems, in using these acids, is corrosion of metallic substrates. To overcome this problem, synthetic inhibitors have been used. On the other hand, most of these inhibitors are toxic. Eco-friendly inhibitors are suitable candidates for replacing synthetic inhibitors, because of their non-toxic nature, abundant sources and low cost. This paper discusses properties, mechanism of inhibition and efficiencies of eco-friendly inhibitors used in acidic media.

Clinical and metabolic response to probiotic supplementation in patients with rheumatoid arthritis: a randomized, double-blind, placebo-controlled trial.

Abstract: Objective This study was performed to determine the effects of probiotic supplementation on clinical and metabolic status of patients with rheumatoid arthritis (RA). Methods Sixty patients with RA aged 25–70 years were assigned into two groups to receive either probiotic capsules (n = 30) or placebo (n = 30) in this randomized, double-blind, placebo-controlled trial. The patients in the probiotic group received a daily capsule that contained three viable and freeze-dried strains: Lactobacillus acidophilus (2 × 109 colony-forming units [CFU]/g), Lactobacillus casei (2 × 109 CFU/g) and Bifidobacterium bifidum (2 × 109 CFU/g) for 8 weeks. The placebo group took capsules filled with cellulose for the same time period. Fasting blood samples were taken at the beginning and the end of the study to quantify related markers. Results After 8 weeks of intervention, compared with the placebo, probiotic supplementation resulted in improved Disease Activity Score of 28 joints (DAS-28) (−0.3 ± 0.4 vs. −0.1 ± 0.4, P = 0.01). In addition, a significant decrease in serum insulin levels (−2.0 ± 4.3 vs. +0.5 ± 4.9 μIU/mL, P = 0.03), homeostatic model assessment-B cell function (HOMA-B) (−7.5 ± 18.0 vs. +4.3 ± 25.0, P = 0.03) and serum high-sensitivity C-reactive protein (hs-CRP) concentrations (−6.66 ± 2.56 vs. +3.07 ± 5.53 mg/L, P < 0.001) following the supplementation of probiotics compared with the placebo. Subjects who received probiotic capsules experienced borderline statistically significant improvement in total- (P = 0.09) and low-density lipoprotein-cholesterol levels (P = 0.07) compared with the placebo. Conclusion Overall, the results of this study indicated that taking probiotic supplements for 8 weeks among patients with RA had beneficial effects on DAS-28, insulin levels, HOMA-B and hs-CRP levels.

Search for a charged Higgs boson in pp collisions at s√=8 TeV

Abstract: A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 +/- 0.5 fb(-1) collected with the CMS detector in proton-proton collisions at root s = 8,TeV. The charged Higgs boson is searched for in top quark decays for m(H +/-) t(b)H-+/- for m(H +/-) > m(t) - m(b). The H-+/- -> tau(+/-)nu(tau) and H-+/- -> tb decay modes in the final states tau(h)+jets, mu tau(h), l+jets, and ll' (l =e, mu) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction B(t -> H(+/-)b) B(H-+/- -> tau(+/-)nu(tau)) = 1.2-0.15% is obtained in the mass range m(H +/-) = 80-160 GeV, while the upper limit on the cross section times branching fraction sigma(pp -> t(b)H-+/-) B(H-+/- -> tau(+/-)nu(tau)) = 0.38-0.025 pb is set in the mass range m(H)+ = 180-600 GeV. Here, sigma(pp -> t(b)H-+/-) stands for the cross section sum sigma(pp -> (t) over bar H+) + sigma(pp -> t (b) over bar H-). Assuming B(t -> H(+/-)b) = 1, an upper limit on sigma(pp -> t(b)H-+/-) of 2.0-0.13 pb is set for m(H +/-) = 180-600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the m(H +/-)-tan beta parameter space in different MSSM benchmark scenarios.