فهرست مطالب

International Journal Of Nanoscience and Nanotechnology
Volume:8 Issue: 4, Autumn 2010

  • تاریخ انتشار: 1391/09/18
  • تعداد عناوین: 6
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  • S. Sabbaghi*, R. Maleki, M. Shariaty-Niassar, M. M. Zerafat, M. M. Nematollahi Pages 185-190
    In this work, several machine learning techniques are presented for nanofiltration modeling. According to the results, specific errors are defined. The rejection due to Nanofiltration increases with pressure but decreases with increasing the concentration of chloride ion. Methods of machine learning represent the rejection of nanofiltration as a function of concentration, pH, pressure and also the experimental rejection. The results are in promising agreement with the experimental data taken from the literature. Six methods for modeling and prediction of rejection by nanofiltration membranes are presented in this study. The models have been trained and tested with a selected data set. Three defined matrices have been used to analyze the performance of the models.
    Keywords: Nanofiltration, Rejection, Machine Learning, modeling, Ion Separation
  • M. Ranjbar*, M. Yousefi, M. Lahooti, A. Malekzadeh Pages 191-196
    In this study, isophthalic acid-zirconium(IV) nanocomposite has been prepared from zirconyl nitrate pentahydrate and potassium iodide, with isophthalic acid, (C8H6O4=Benzene-1,3-dicarboxylic acid) as a ligand, via sonochemical method in ethylene glycol and methanol as solvents. The crystalline tetragonal ZrO2 has been produced by thermal decomposition of isophthalic acid-zirconium(IV) nanocomposite as precursor. Characterization of nanocomposite was carried out using element analysis, Fourier transfer infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA) techniques. The results demonstrated that, pure zirconia with particle size of about 49 nm was obtained in which methanol has been used as solvent during the reaction, particle sizes was significantly reduced to about 20 nm, when ethylene glycol used as solvent during formation of the nanocomposite isophthalic acid-zirconium (IV) as precursor.
    Keywords: Zirconium oxide, Sonochemical method, Hydrothermal method, Isophthalic acid, Nanocomposite
  • A. K. Vala*, S. Shah Pages 197-206
    Recently, biosynthesis of nanoparticles has received attention due to an increasing need of developing rapid, simple and ecofriendly protocol. Pathogenicity of some of the organisms and lengthy reaction are the drawbacks involved with biosynthesis. We describe a simple protocol for rapid synthesis of silver nanoparticles through biological route using a marine-derived fungus Aspergillus niger. Silver nanoparticles biosynthesis could be achieved within 3 minutes (which otherwise generally takes about 24h) by altering pH of the reaction mixture. Silver nanoparticles biosynthesized at different pH have been observed to have antimicrobial potentials against four test bacteria (viz. Bacillus megaterium, Proteus vulgaris, Staphylococcus aureus and Shigella sonnei). Further, combined effect of Gentamicin and biosynthesized silver nanoparticles and effect of culture condition (pH) on antimicrobial effect have also been studied. Based on the findings it is concluded that the present study provides a solution to the drawbacks involved in biosynthesis of silver nanoparticles, an ecofriendly approach. It is envisaged that the biosynthesized silver nanoparticles alone, or their combination can be potentially used as effective agents against pathogens.
    Keywords: Antibacterial activity, Biosynthesis, Filamentous fungi, Silver nanoparticles, Microbial growth, Environmental preservation
  • A. Ghasemi, A. M. Davarpanah, M. Ghadiri* Pages 207-214
    Oxide nanoparticles of Fe-Co-Ni were prepared in six different compositions by co-precipitation method. The as-synthesized nanoparticles were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron microscope (FESEM), Fourier Transform Infrared (FT-IR) and Vibrating Sample Magnetometer (VSM). It was found that the nanoparticles had mean crystalline size of 30-55 nm and spherical shape. Specific surface area of the nanoparticles was between 27.47x104 cm2/g to 141.4x104 cm2/g which had been calculated by X-Ray Diffraction data. The magnetic measurements of nanoparticles were done at room temperature and found that nanoparticles exhibit a ferromagnetic behavior with different values of saturation magnetization and coercivity.
    Keywords: Nanostructured materials, Precipitation, X-ray diffraction, Magnetic measurements, Nanoparticles
  • Z. Hejri*, A. Ahmadpour, A. A. Seifkordi, S. M. Zebarjad Pages 215-226
    A novel Starch/Poly (vinyl alcohol)/nano-Titanium dioxide (ST/PVA/nano-TiO2) biodegradable nanocomposite film was prepared by homogeneously dispersed TiO2 nanoparticles in different ratios of starch/PVA-based materials, via a solution casting method. Glycerol was used as plasticizer. The mechanical and thermal properties of films were studied using tensile and perforation strength tests and thermogravimetric analysis (TGA). In order to determine the effective parameters on mechanical properties of prepared films, a general full factorial experimental design approach was used. ST/PVA/TiO2 nanocomposites were also characterized by scanning electron microscopy (SEM). The results of mechanical analysis showed that ST/PVA films with higher content of PVA had much better mechanical properties. In thermal analysis it was found that addition of TiO2 nanoparticles have considerable effects on the thermal stability of the films. This enhancement of thermal stability can be attributed to an improvement in the interfacial adhesion and compatibility between the nano- TiO2 and matrix, due to the treating effect of plasticizer and film forming process. SEM micrographs, taken from the fracture surface of samples, illustrated a quite uniformly dispersion of TiO2 nanoparticles in the matrix. Moreover, addition of PVA to the composition of film made it softer and more flexible.
    Keywords: Nanocomposite, Biodegradable, Nano, TiO2, Mechanical Properties, Thermogravimetric analysis
  • M. H. Korayem*, S. Sadeghzadeh Pages 227-246
    The continuum based approaches don’t provide the correct physics in atomic scales. On the other hand, the molecular based approaches are limited by the length and simulated process time. As an attractive alternative, this paper proposes the Fixed Interfacial Multiscale Method (FIMM) for computationally and mathematically efficient modeling of solid structures. The approach is applicable to multi-body mechanical systems. In FIMM, a direct link between the nano field atoms and macro field nodes by the local atomic volume displacements associated with every macro field node in their common zone has been replaced with the previous methods. For a complete model of the macro section, a nine-noded Lagrange element has been developed, and for small dimensions, the Sutton-Chen potential (for problems of mechanics) has been used. In the presented model, the undesirable effects of free surfaces, common surfaces, and surfaces close to the interface with the macro field have been eliminated, and after presenting a practical and noteworthy procedure for the dynamics of systems in general, seven problems (in the form of three examples) have been offered to showcase the practicality
    Keywords: Multi, scale model, Open systems, Dynamics, Macro, nano mechanics, coupling model, FIMM