International Journal of Nano Dimension
Year:2012 | Volume:2 | Issue:4 (8)|Papers Count:10

This paper discusses different important gas permeation models such as "Maxwell", "Bruggeman", "Lewis-Neilson", and "Pal" models to predict "Mixed Matrix Membranes" (MMMs) performance. The main parameter considered and discussed is the permeability of Hydrogen on Carbon Nanotubes (CNTs)-MMM. For evaluation of the theoretical models, experimental data of permeability for H2 were compared to the theoretical models. The results revealed that, the existing models are not appropriate for evaluation of the permeability of the carbon nanostructure-based MMMs. Therefore, correction factors are needed to fit the selective permeability of carbon nanostructure-based MMMs for selective separation of various gaseous such as H2 or CO2. This correction factor robustly depends on the morphology of carbon nanostructures, the defect, kind and amount of metal/metal oxide nanoparticles, doped on carbon substrate and functional groups in the carbon matrix. Hence, to be in a good agreement with experimental data for separation of H2 from CO2, the correction value was estimated to -0.0022 for single-walled carbon nanotubes (SWCNTs), -0.0032 for pure multi-walled carbon nanotubes (MWCNTs),-0.0044 for carbon nanofibers (CNFs).

The study reports some preliminary investigations on the template free synthesis of a scantly investigated polyaniline (PANI) derivative-Phenylenediamine (PDA) by template free method in the presence of Oxalic acid (OA) (dopant), using Ammonium Per sulfate as oxidant. Polymerization of Phenylenediamine (PDA) was confirmed by the FT-IR as well as UV–visible studies. The morphology of Phenylenediamine doped with oxalic acid shows nanofibres was confirmed by Scanning electron microscopy (SEM) studies. It is also observed that the change in morphology changes the electrical conductivity. The oxalic acid as dopant has beneficial effect on the electrical conductivity.

This paper proposed analytical solutions for the buckling analysis of rectangular single-layered graphene sheets under in-plane loading on all edges simply is supported. The characteristic equations of the graphene sheets are derived and the analysis formula is based on the nonlocal Mindlin plate. This theory is considering both the small length scale effects and transverse shear deformation effect. Nonlocal elasticity theory takes into account the small length scale effects as examining nanostructures such as nanoplates. It is presented graphically that the small scale or nonlocal effects on the nondimensional buckling loads in the presence of aspect ratio and buckling modes.

In this article, ZnO and ZnO: Mn nanoparticles prepared by reverse micelle method. The various crystalline properties of these nanoparticles such as size, d-spacing, strain, stress, dislocation density and texture coefficient have been calculated with the help of XRD spectrum. The XRD results indicated that the synthesized ZnO and ZnO: Mn nanoparticles have a pure wurtzite (hexagonal phase) structure. It can be seen that the highest texture coefficient was in (002) plan for nanoparticles. The optical band gap energy of ZnO and ZnO: Mn nanoparticles have been analyzed by using UV-Vis data. The photoluminescence spectra of the nanoparticles indicated their high structural and optical quality.

The nano sized TiO2 and ZnO are the most active photocatalysts. Methylene blue was used as a reference molecule for the photo catalytic degradation. The TiO2 and ZnO can totally remove methylene blue dye. The effect of various process parameters like initial concentration, contact time, dose of catalyst and pH on the extent of removal of dye by photo catalysis in presence of TiO2 and ZnO was studied. The results showed that the percentage of dye removal increases with increase in contact time. The optimum contact time was fixed at 180 minutes for both nanomaterials. The results of this study reveal that the dyes could be removed by semiconducting nanomaterials assisted photo catalytic degradation. The semiconducting materials were analyzed by XRD and SEM before and after degradation of methylene blue.

N, N-dichloropolystyrene sulfonamide as a decontaminant was synthesized in 5 steps from styrene monomer. Styrene was first polymerized. Then, sulfonation reaction was performed by H2SO4 (c) followed by chlorination with POCl3 obtain chlorosulfonated polystyrene. Amidification reaction was then applied to get sulfonamide resin. Sulfonamide resin was treated with sodium hypo chloride to obtain N, N-dichloropolystyrene product. The products of each step were characterized by FT-IR technique. The active chlorine content of final product was measured by standard iodometry titration. Composite nanofibers of polystyrene – N, N-dichloropolystyrene sulfonamide (PS/DPSA) were prepared with electro spinning technique. The appropriate nanofibers obtained under optimized conditions such as applied voltage, distance between the collection plate and nozzle, kind of solvent and concentration of composite solution. The diameter of nanofibers was determined by scanning electron microscope (SEM) and range of nanofiber was about 160-300nm. The decontamination reaction of 2-chloroethyl ethyl sulfide (2-CEES) a simulant of sulfur mustard (S.M.) by composite nanofibers of PS/ DPSA was monitored by gas chromatography (GC). Also the reaction products of decontamination reaction were identified by gas chromatography – mass spectroscopy (GC-MS). These composite nanofibers are able to decontaminate 2-CEES in 7 minutes.

Nano crystalline ZrO2 with particle size of about 38 nm was directly synthesized by sol-gel auto-combustion method. The overall process involved three steps: formation of homogeneous sol at 50-55oC, formation of dried gel at 110oC, and combustion of the dried gel at 400oC. Experiments revealed that ZrO2 dried gel derived from glycine (Fuel) and nitrate sol exhibited self propagating combustion at 400oC that it was ignited in air. The auto-combustion was considered as a heat-induced exothermic oxidation-reduction reaction between nitrate ions and carboxyl group. After auto-combustion, products were calcined at 650oC. ZrO2 nano particle were incorporated into the A356 aluminum alloy by a mechanical stirred at 850oC and after that, cylindrical specimens were cast. After preparing the samples, mechanical properties were measured. The results of microstructure, compression and hardness tests indicated that addition of ZrO2 nano particulates to aluminum matrix composites improved the mechanical properties. Also, Based on experiments, it was revealed that the presence of ZrO2 reinforcement led to significant improvement in hardness and compressive strength.

The aim of the present study was to prepare nano-sized calcium fluoride (CaF2). Calcium fluoride nanoparticles were synthesized by CaCl2.6H2O and ammonium fluoride. Nanoparticles were synthesized by co-precipitation method. The synthesized nanocrystals were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). The crystallite size estimated using Scherer's formula was found to be in the range of 20–30nm for nanocrystals synthesized by this method. The morphological features as studied using SEM revealed that the nanoparticles were agglomerated, crispy with porous.

Calcium doped nickel ferrite powders have been prepared by sol-gel combustion technique. Metal nitrates, such as calcium nitrate, nickel nitrate and ferric nitrate, were used as the source materials and citric acid and polyvinyl alcohol were used as the burning agent and agglomeration reducing agent, respectively. The average crystallite size of the prepared ferrite was in the order of ~70- 92 nm. Due to the vast survey on calcium based ferrite materials with the existing ferrites, it was found that the research on calcium ferrite is scanty compared to other ferrite. Moreover, there is no report available on Calcium doped with nickel ferrite materials. Therefore, we report the structural studies of Ni0.5Ca0.5Fe2O4 synthesized by sol-gel combustion method. The structure, cubic morphology, and the identification of functional groups of the calcium-doped nickel ferrite were analyzed systematically using several analytical tools.

In this study the hardness SWCT was calculated with B3LYP,HF method and 3-21G,6-31G,6-311G basis set .Then it was investigated with the best method(B3LYP) and basis set(6-31G) to study the adsorption effects CO2 on the hardness of SWCNT with gap HOMO-LUMO in two shape: Horizontal, Vertical and Top-Center-Bridge and We also provide the effects of CO2 adsorption on the electronic properties(DOS) of the CNTs. The soft wares which were used in this study were Gaussian 03 w, Gauss view 5.0w and Nano tub modeler. The Purpose of this study is to compare the effects of the basis set & CO2 adsorption on the hardness of SWCNT (8, 0) in gases phase.