Thermal conductivity modeling of nanofluids with ZnO particles by using approaches based on artificial neural network and MARS

Journal of Thermal Analysis and Calorimetry - Nanofluids are attractive alternatives for the current heat transfer fluids due to their remarkably higher thermal conductivity which leads to the...     

Using the generalized maximum covering location model to control a project’s progress

Project control consists of monitoring a project’s progress at so called control points, finding possible deviations from the baseline schedule and if necessary, making adjustments to the deviated schedule subject to the available control budget, the adjusting strategies and also other technical and environmental possibilities in order to bring the schedule back on the right track. In this study, we adapt for the first time the generalized maximum covering location model to determine the adjusting strategies such that the maximum control coverage is achieved, i.e. under the given constraints, a schedule that is globally as close to the baseline schedule as possible is obtained. Numerical examples are given to illustrate the intricacies of the proposed method and also to demonstrate its applicability.

     

Enhancing of asphaltene adsorption onto Fe3O4 nanoparticles coated with metal-organic framework Mil-101 (Cr) for the inhibition of asphaltene precipitation

In this study, the potential of MOF (Mil-101-Cr)-coated Fe₃O₄ magnetic nanoparticles (Fe₃O₄-MOF MNPs) for asphaltene adsorption was investigated for the first time and the results were compared with magnetic Fe₃O₄ nanoparticles (Fe₃O₄ MNPs). The coprecipitation method was used for the synthesis of both nanoparticles and were verified using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM). The initial asphaltene concentration, nanoparticles concentration, and temperature were the investigated parameters that influenced the adsorption capacity. Increasing the asphaltene concentration, decreasing the mass of nanoparticles, and reducing the temperature could enhance the maximum asphaltene adsorption capacities of 0.79 for Fe₃O₄ MNPs and 0.98?mg?m^?2 for Fe₃O₄-MOF MNPs. Adsorption isotherms tests showed that the Langmuir model was in agreement with the experimental data. In addition, the evaluation of adsorption kinetics demonstrated that the pseudo-second-order Lagergren model predicted the results more precisely. The amount of asphaltene adsorption for Fe₃O₄-MOF MNPs was higher than that for Fe₃O₄ MNPs. These results recommend the application of MOF as an appropriate and effective coating for enhancing asphaltene adsorption.     

Evaluation of new 99mTc-labeled HYNIC-bombesin analogue for prostate cancer imaging

Journal of Radioanalytical and Nuclear Chemistry - In this study, we introduce a new 99mTc-radiolabeled bombesin derivative for imaging of prostate cancer (PC). We used 6-hydrazinonicotinamide...     

Optimisation of a hybrid photoneutron source in a linear accelerator using GEANT4 and MCNPX Monte Carlo codes

The \(\alpha \) decay half-lives of hyper and normal isotopes of Po nuclei are studied in the present work. The inclusion of \(\Lambda \)–N interaction changes the half-life for \(\alpha \) decay. The theoretical predictions on the \(\alpha \) decay half-lives of normal Po isotopes are compared with experimental results and are seen to be matching well with each other. The neutron shell closure at \(N = 126\) is found to be the same for both normal and hypernuclei. The Geiger–Nuttal (G–N) law for \(\alpha \) decay is unaltered in the case of hypernuclei. The hypernuclei will decay into normal nuclei by mesonic or non-mesonic decay modes. Since the half-lives of normal Po nuclei are well within the experimental limits, our theoretical results suggest experimental verification of the \(\alpha \) emission from hyper Po nuclei in a cascade process.     

Complexation of Tungsten(VI) with Methyliminodiacetic Acid at Different Ionic Strengths

The results of this research give ionic strength dependence patterns for the complexation of tungsten(VI) with methyliminodiacetic acid at T?=?298?K. The formation data reported in this work were obtained at different ionic strengths (0.1?<?I/mol·dm^?3?<?1.0) of sodium perchlorate on the basis of Job??s continuous variation method, which show that a 1:1 complex forms at pH?=?7.50. UV experimental data were collected for the calculation of the stability constants according to the extended Debye?CHückel theory, the specific ion interaction theory and the parabolic model. Finally, these three models have been compared.     

A comparative study to evaluate the performance of coated Fe3O4 nanoparticles for adsorption of asphaltene from crude oil in bench scale

The present study was conducted to evaluate the performance of magnetic Fe₃O₄ nanoparticles coated with polythiophene (PT), Mil-101 (Cr) (MOF), graphene oxide (GO), SiO₂, and chitosan for adsorption of asphaltene from crude oil in a bench scale setup. All nanoparticles were synthesized using co-precipitation method. The characteristics of nanoparticles were verified using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and field emission scanning electron microscope (FESEM) analyses. The concentration of nanoparticles was kept constant at the optimum value of 10g?L^?1. The amount of asphaltene adsorption was determined at different contact times of 0.5, 0.75, 1, 2, and 4 hours. The results showed that the adsorption increased with contact time and reached equilibrium after about 2 hours in both continuous and batch experiments. The amount of asphaltene adsorption was lower in continuous experiments compared to batch experiments. However, it was found that magnetic nanoparticles are applicable for inhibition of asphaltene precipitation under flow conditions. Furthermore, polythiophene coating on magnetic Fe₃O₄ nanoparticles had the highest capacity for asphaltene adsorption. Besides, by applying a magnetic field, the magnetic nanoparticles that adsorbed asphaltene can be separated from crude oil to prevent asphaltene aggregation and precipitation.