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11.
Mehrorang Ghaedi Gholamreza Karimipour Elham Alambarkat Arash Asfaram Morteza Montazerozohori Sahar Izadpanah 《International journal of environmental analytical chemistry》2015,95(11):1030-1041
The development of a solid-phase extraction (SPE) procedure for the pre-concentration of trace amounts of Pb2+ ion on 2-furan-2-yl-1-furan-2-ylmethyl-1H-benzoimidazole loaded on activated carbon modified with silver nanoparticles (L-AC-Ag-NP) was presented. The metal ion retained on the sorbent was quantitatively determined via complexation with the ligand. The complexed metal ion was efficiently eluted using 10 mL of 4 mol L?1 sulphuric acid in 10 w/v% acetone. The influences of the analytical parameters, including pH, amounts of the ligand and the solid phase, eluent conditions and sample volume, on the recoveries of the metal ion were optimised. Using the optimised parameters, the linear response of the SPE method for Pb2+ ion were in the ranges of 0.2–160 µg L?1, and the detection limit for Pb2+ ion was 0.034 µg L?1. The proposed method exhibits a pre-concentration factor (PF) of 80 and an enhancement factor of 30 for Pb2+ ion. The presented results demonstrate the successful application of the proposed method for the determination of Pb2+ ion in some real samples with high recoveries (>93%) and reasonable relative standard deviation (RSD < 2%). 相似文献
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Mohammad HojjatSeyed Gholamreza Etemad Rouhollah BagheriJules Thibault 《Experimental Thermal and Fluid Science》2011,35(7):1351-1356
Forced convection heat transfer of non-Newtonian nanofluids in a circular tube with constant wall temperature under turbulent flow conditions was investigated experimentally. Three types of nanofluids were prepared by dispersing homogeneously γ-Al2O3, TiO2 and CuO nanoparticles into the base fluid. An aqueous solution of carboxymethyl cellulose (CMC) was used as the base fluid. Nanofluids as well as the base fluid show shear-thinning (pseudoplastic) rheological behavior. Results indicate that the convective heat transfer coefficient of nanofluids is higher than that of the base fluid. The enhancement of the convective heat transfer coefficient increases with an increase in the Peclet number and the nanoparticle concentration. The increase in the convective heat transfer coefficient of nanofluids is greater than the increase that would be observed considering strictly the increase in the effective thermal conductivity of nanofluids. Experimental data were compared to heat transfer coefficients predicted using available correlations for purely viscous non-Newtonian fluids. Results show poor agreement between experimental and predicted values. New correlation was proposed to predict successfully Nusselt numbers of non-Newtonian nanofluids as a function of Reynolds and Prandtl numbers. 相似文献
13.
Gholamreza Talebi 《Indagationes Mathematicae》2019,30(4):741-743
The results in Section 4 of the paper “On the Taylor sequence spaces and upper boundedness of Hausdorff matrices and Nörlund matrices” that appeared in this journal (28 (3) (2017), 629–636) are valid only for those summability matrices whose absolute row sums do not exceed 1. For other summability matrices, the corrected results are presented and proved. 相似文献
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Nonlinear Dynamics - In this article, the effects of the changes in the mass of the floating wind turbine (as a multi-body system) on its nonlinear vertical vibrations are investigated. The... 相似文献
16.
Gholamreza Vaghar-Lahijani Mohammad Saber-Tehrani Parviz Aberoomand-Azar Mojtaba Soleimani 《Journal of Analytical Chemistry》2018,73(2):145-151
In this study, an effective method of ultrasound-assisted ionic liquid based dispersive liquid–liquid microextraction (UA?IL?DLLME) coupled with HPLC was applied for extraction and determination of two antidepressant drugs: venlafaxine hydrochloride and amitriptyline hydrochloride from human plasma samples. Three ionic liquids were studied: 1-butyl-3-methyl imidazolium hexafluorophosphate, 1-hexyl-3- methyl imidazolium hexa-fluoro-phosphate, and 1-octyl-3-methyl imidazolium hexafluorophosphate [C8MIM][PF6]. Various factors affect the stages and efficiency of extraction, some of which are pH of sample solution, type and volume of ionic liquid, the time of ultrasonication, centrifuging time and rate, and the ionic strength of solution. In this research, optimum conditions were obtained as 55 μL of [C8MIM][PF6] selected as ionic liquid, pH 11, 2% NaCl, 4 min ultrasonication and 5 min centrifuging at 3500 rpm. Under the optimized conditions, the linearity was obtained in the range of 0.2 to 250 μg/L. The limits of detection were 0.5 μg/L for venlafaxine and 0.8 μg/L for amitriptyline. Pre-concentration factors were 1.3 × 103 for venlafaxine and 1.2 × 103 for amitriptyline. The UA?IL?DLLME method coupled with HPLC was successfully used for the determination of venlafaxine and amitriptyline spiked into the real samples of human plasma. 相似文献
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Gholami Mohammad Reza Akbari Omid Ali Marzban Ali Toghraie Davood Shabani Gholamreza Ahmadi Sheikh Zarringhalam Majid 《Journal of Thermal Analysis and Calorimetry》2018,134(3):1611-1628
Journal of Thermal Analysis and Calorimetry - In this research, the laminar and forced flow and heat transfer of oil/multi-walled carbon nanotubes nanofluid in a microchannel have been numerically... 相似文献
18.
Marjaneh Jafari Fesharaki Gholamreza Nabiyouni Bita Shahdoost Seyed Farshad Akhtarianfar 《Journal of Cluster Science》2016,27(3):1005-1015
NiFe2?x Bi x O4 (x = 0, 0.1, 0.2, 0.3) nanoparticles with various grain sizes were synthesized via annealing treatment followed by ball milling of its bulk component materials. Commercially available bismuth, nickel and iron oxide powders were first mixed and then annealed at 1200 °C in an oxygen environment furnace for 4 h. The samples were then milled for 2 h by high-energy ball milling. X-ray diffraction (XRD) pattern indicated that in this stage the samples are single phase. The microstructure investigation was carried out by a scanning electron microscope with maximum magnification of 30,000. The average grain size for different samples was estimated by XRD technique and transmission electron microscopy. Magnetic behavior of the samples at room temperature was studied using an alternating gradient force magnetometry. The Néel temperature of the powders was measured by a Faraday balance. Based on magnetic studies, increase in bismuth content leads to a decrease in the saturation magnetization, coercive field and Néel temperature. This can be attributed to the substitution of Bi3+ ion in the ferrite system as a nonmagnetic cation. 相似文献
19.
Gholamreza Javahery Bruce Thomson 《Journal of the American Society for Mass Spectrometry》1997,8(7):697-702
The gas collision cell of a triple quadrupole mass spectrometer has been modified to consist of ten short quadrupole rod segments that allow an axial field to be applied to the cell in order to make measurements of ion mobility. The radiofrequency (rf)-quadrupole field provides effective radial confinement that greatly reduces diffusional losses at low pressure. The mobilities of mass-selected ions from an ionspray source have been measured at a pressure of 8 × 10?3 torr at electric fields of 0. 1 to 3 V/cm, and used to calculate the collision cross sections of the ions. The measured cross sections compare well with those measured by other techniques. 相似文献
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Mohammad Bagher Majnooni Bahareh Mohammadi Ronak Jalili Gholamreza Bahrami 《液相色谱法及相关技术杂志》2016,39(19-20):877-881
A new high-performance liquid chromatographic method is described for the determination of fatty acids in seed oils. The method was based on precolumn derivatization with 9-fluorenylmethyl chloroformate as a labeling agent and fluorescence detection. Fatty acids were extracted from the samples and subjected to derivatization with the reagent at 60°C for 10?min. The chromatographic separation of 14 fatty acids (C10–C22) was achieved on a combined loading compression octadecyl sulfate (CLC-ODS) column with a run time of 30?min. Three-step gradient elution of a mobile phase consisted of acetonitrile and water was used, and the signal was monitored at excitation and emission wavelengths of 265 and 315?nm, respectively. The method indicated favorable sensitivity and reproducibility for fatty acids’ derivatives. The detection limits, at a signal-to-noise ratio of 3, were 0.01–0.05?µg/ml and relative standard deviations (RSDs) were less than 0.27%. Excellent linear responses were observed with coefficients of 0.9995. This method was applied to quantify fatty acids in white, brown, and black sesame seeds’ oil. 相似文献