International Journal of Nano Dimension
Volume:6 Issue: 3, Summer 2015

Polyacrylonitrile (PAN) membranes with nano-porous surface and high hydrophilicity were fabricated by addition of polyoxyethylene (40) nonylphenyl ether (IGEPAL) as an additive in the casting solution. The membranes were prepared from PAN/IGEPAL/1-Methyl-2-pyrrolidone (NMP) via phase inversion induced by immersion precipitation technique. Pure water was used as coagulation medium. The effects of adding IGEPAL and the PAN concentration on the morphology, wettability, and permeability of the prepared membranes were studied. The morphological studies were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the wettability and permeability of membranes were examined by contact angel measurements and permeation experiments. The contact angle measurements indicate that the hydrophilicities of membrane enhanced by the addition of IGEPAL surfactant and decreasing the PAN concentration in the casting solution. According to SEM and AFM analysis, it was found that the addition of IGEPAL and change concentration of polymer have a significant influence on structure of the membrane top surface and the sub-layer. In addition, it was found that decreasing the PAN concentration and addition of IGEPAL resulted in the formation of membranes with high permeability.

The present study was carried out to investigate the potential of carboxylate group functionalized Multi-walled carbon nanotubes (MWCNT−COOH) adsorbent for the removal of Methyl orange (MO) textile dye from aqueous solutions. The effects of pH, shaking time and temperature on adsorption capacity were studied; the contact time to obtain equilibrium at 298 ˚K was fixed at 25 min. The effect of temperature on adsorption process was evaluated from 298 to 338 ˚K. Results showed that removal of Methyl orange increased with increasing contact time and decreased with increasing pH and temperature. For Methyl orange dye, the equilibrium data were best fitted to The Langmuir isotherm model. The adsorbent was characterized by infrared spectroscopy, and scanning electron microscopy. The pseudo-second-order kinetic model provided the best fit to the experimental data compared with The Elovich or pseudo-first-order or intra-particle diffusion kinetic adsorption models.

Using of nanofluids and ducts with corrugated walls are both supposed to enhance heat transfer, by increasing the heat transfer fluid conductivity and the heat transfer area respectively. Use of a diverging duct with a jet at inlet section may further increase heat transfer by creating recirculation zones inside the duct. In this work two-dimensional incompressible laminar flow of a nanofluid entering a diverging channel with sinusoidal walls through a jet at inlet section, is numerically investigated. Effects of aspect ratio (duct-to-jet height ratio), wall-wave amplitude, wall wavelength, Reynolds number, nanoparticle volume fraction and the size of nanoparticles on the flow structure and heat transfer are investigated. The results show that by increasing the Reynolds number, wall wave amplitude and nanoparticle volume fraction, the duct averaged Nusselt number will increase, while the wall wavelength and the particle size have an adverse effect. The inlet jet has the strongest effect on heat transfer at the aspect ratio of 4.

Nanoparticles of Mn0.5Zn0.5-xCdxFe2O4 with x varying from x = 0.0 to 0.3 were prepared by wet chemical co-precipitation method. The structural and magnetic properties were studied by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and Electron Paramagnetic Resonance (EPR) technique. The lattice constant increases with increase in Cd content. This increase in the lattice constant is due to larger ionic radii of the Cd2+ (0.97 Å) ions as compared to Fe3+ (0.64 Å) ions. The intensities of the planes (220) and (440), increases with increasing Cd2+ ion concentration. This shows that Cd2+ ions occupy tetrahedral A sites and octahedral B sites in the nano dimension against their chemical preference for A site. The line width (ΔHpp) and the g value of the Electron paramagnetic resonance (EPR) signal decreases with increase in the Cd content. The magnetic moment of all the samples up to x = 0.2 calculated from EPR studies are lower when compared to the theoretical values. This lower value of magnetic moment confirms the existence of non collinear magnetic structure arising due to significant amount of spin disorder existing at B site.

The nanomaterials have important application in different field of science such as biology and pharmacology, which draws the attention of biologists towards this field of study more than before. As the worldwide mortality rate is high due to the pathogens and especially because of the bacteria associated Aeromonas and the antibacterial effect of metal nanoparticles is well known for centuries, these materials can be used to annihilate Aeromonashydrophila. In this study, silver oxide nanoparticles were synthesized by sol-gel procedure and antibacterial activity of silver oxide nanoparticles as a function of particle concentration against gram-negative bacterium Aeromonashydrophila ATCC 7966T was carried out in liquid as well as solid growth media. Synthesized Ag2O nanoparticles (NPs) were characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM) and transmission electron microscopy (TEM). The average size of the Ag2O NPs determined through transmission electron microscopy (TEM) 15 nm. The bactericidal effect of silver oxide nanoparticles was compared based on the diameter of inhibition zone in well diffusion tests in nutrient culture media. Minimum bactericidal concentration (MBC) of nanoparticles dispersed in peptone water, liquid cultures in 22-25 ºC for 24 h were determined.

Maybe viscosity in drilling fluid is the most important parameter because cutting removal from well are task of viscose fluid. If viscosity of fluid is less than particular value, cutting will settle down in well and drilling operation will be stopped. In this study, synthesis of Alumina/Polyacrylamide nanocomposite through solution polymerization method was performed. Rheological behavior of mud drilling fluid after addition different amount of synthetic nanocomposite was measured for different periods of time. One of the major disadvantages of polymeric fluid is shear thinning property, called thixotropy. In this work we also test the influence of additive nano alumina particle in reduction of thixotropic behavior of drilling fluid. Adding different amount of synthetic nanocomposite increases the viscosity of drilling fluid up to more than 300 cP for both fresh and salt water mud at only 4 wt% and about 100 cP at2 wt% also reduces the rate of thixotropic behavior more than 5% after adding nano particles instead of free nano particle polymer.

Nano-sized BaTiO3 powders with particular Nb concentrations were prepared by Rotary- Hydrothermal (RH) method. Hydrothermal method was used at 180 °C for 5 hours with new Ti pressure and the teflon vessel was rotated at a speed of 160 rpm during the hydrothermal reaction. New hydrothermal method was used instead of previous solid state reaction for the system BaTiO3±Nb2O3 in high temperature to achieve nano sized particles in lower time and temperature. Synthesis with Rotary-hydrothermal has the advantages of faster crystallization, decreased crystal size, more homogenous distribution of dopants at lower temperature and time in comparison with the solid state method. In case of the phase evolution studies the X-ray diffraction patterns (XRD) measurements and Raman spectroscopy were performed. The Transmission Electron Microscope (TEM) and the Field Emission Scanning Electron Microscopy (FE-SEM) images were taken for the detailed analysis of the grain size, surface and morphology. Synthesis of Nb doped BaTiO3 with the Rotary- hydrothermal provided advantages of fast crystallization and decreased crystal size.

Pyrano [2,3-d] pyrimidinone derivatives have received considerable interest from the pharmaceutical industry due to their wide range of interesting biological and therapeutic properties. Nano Al2O3 was found to be a highly efficient solid acid catalyst for the preparation of pyrano [2,3-d] pyrimidinone derivatives from the reaction of barbituric acid, aryl aldehyde and malononitrile. Al2O3 nanoparticles with the average diameter of 15 nm were used four different contents of 10, 15, 20 and 25 mol%. Present methodology offers several advantages, such as high yields, short reaction time, simple procedure with an easy work-up and mild reaction conditions. The products were obtained in high yields under reflux in H2O:EtOH (1:1). We believe this applicability of nano Al2O3 with mentioned advantages makes our method superior over all previous reported methods to the synthesis of pyrano [2,3-d] pyrimidinone derivatives. The structures of the products were characterized by their physical constants and comparison of their melting points with those of authentic samples.

Using ab initio calculations, the hydrogen desorption from Magnesium hydride (MgH2) was studied. We presented the calculated nuclear quadrupole coupling constants (NQCCs) of hydrogen atom in various systems of MgH2. The effect of interactions of some metal atoms as well as Boron atom with MgH2 host matrix; (MgH2+M) nanostructures (M=Al, Ti, V, Fe, Ni and B); were studied and 2H-NQCCs were calculated. From results, introduction of B decreased 2H-NQCC and consequently trend of decrease of charge density in the presence of B was observed. In the other hands introduction of B destabilized initial structure of MgH2, But in (MgH2+M) nanostructures(M=Al, Ti, V, Fe and Ni) the 2H- NQCCs were larger than those of pure MgH2 and consequently more difficult condition for hydrogen desorption were created. However at sufficiently low B concentration (Mg15BH32); the calculation predicted existence of stable dopant system with greater 2H-NQCC.The electric field gradient (EFG) at the site of quadrupolar nuclei were calculated to obtain NQCC parameters at HF/3-21G level of theory.

Nanocomposite of ZrO2/ZnO was prepared under ultrasonic irradiation by sol gel process from directly mixing Zirconium and Zinc gels. The mixture was placed under ultrasonic irradiation for 2 hours. After the aging time and filtration of the reaction mixture, the filtrated composite gel was calcinated at 500 °C for 3h in furnace. The precursor gels of zirconium and zinc were prepared from dissolving of ZrCl4 and Zn(CH3COO)2.2H2O into deionized water(DI). Nano ZnO, Nano ZrO2 and ZrO2/ZnO nanocomposite were characterized. The FT-IR analysis and the XRD study were exhibited that the crystal structure and purity of the ZrO2/ZnO nanocomposite FESEM images were indicated the morphology and the average size of the NPs. The average size of the Nano ZnO, Nano ZrO2 and ZrO2/ZnO nanocomposite were determined 54, 23and 37 nm respectively. The photocatalytic performance was increased when nanocomposite of ZrO2/ZnO was used to degradation of Congo red (CR) solution. The ZrO2/ZnO nanocomposite was shown higher photo-degradation efficiency of Congo red than of pure nano ZrO2 and nano ZnO.

Polypropylene / polystyrene blends containing montmorillonite (MMT) were prepared using a twin screw extruder followed by fiber spinning. The melt intercalation of PP and PS alloys was carried out in the presence of a compatibilizer such as maleic anhydride-g-polypropylene (MPP). The crystallization morphology, thermal behaviors and mechanical properties of polypropylene/polystyrene (PP/PS) nanoclay blends nanocomposite fibers were investigated in the present work. The improved adhesion between the phases and fine morphology of the dispersed phase contributed to the significant improvement in the properties and thermal stability of the final nanocomposite materials. On the basis of this result, we describe a general understanding of how the morphology is related to the final properties of OMMT- incorporated PP/PS blends.

Porous Silicon (PS) samples have been prepared by electrochemical anodization of p-type silicon wafer by varying HF concentrations in the electrolytic solution. The structural, surface morphological, optical and surface composition analysis of the prepared samples were done by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopy studies respectively. The grain sizes of PS were determined by XRD study. The porosity of PS samples was estimated by using the parameters obtained from the SEM images by the geometrical method. The porosity of the samples was found to vary between 11% and 84% due to the variation in HF concentration in the electrolytic solution. The refractive index and dielectric constant values of PS as a function of porosity were determined by Effective Medium Approximation methods. Strong visible emission peak at 498 nm, with no apparent shift with respect to variation in etching parameter, is observed in Photoluminescence study. The surface bonding and their vibration modes of the PS were determined by transmission FTIR spectroscopy.

The term Nanofluids was first coined by Sir Stephen Choi in 1995 at Argonne National Laboratory, U.S.A. Since the discovery, nanofluid have been explored as heat transfer fluids. Nanofluids increased the thermal conductivity of existing coolants (Water, Ethylene glycol) by a magnitude of hundred times which made them attractive for miniaturization of electronic devices. From 1995 till 2008 nanofluid research was focused on enhancing the thermal conductivity of the base fluid by various parameters like shape of nanoparticle, volume fraction of base fluid and material of base fluid and composition of nanoparticle. A lot of theoretical models have been evolved in an attempt to explain the basic mechanism of heat transfer in a nanofluid. Research has been with respect to viscosity, stability, thermal conductivity and convective heat transfer coefficients of nanofluids. From 2008 nanofluids have been investigated for their electrical properties and reported as electrical conductivity enhancers for base fluid. The latest trend in nanofluid is towards optical properties of nanofluid for direct absorption solar collectors.