Journal of Nano Structures
Volume:2 Issue: 4, Autumn 2013

SAE 20W50 engine oil to study the rate of their effects on the properties of engine oil. Multi-walled carbon nanotubes (MWCNTs) and vanadium oxide nanotubes (VONTs) has been used as two different additive materials, one of them is carbonic and the other is metallic oxides and their effect on different parameters containing viscosity, thermal conductivity coefficient, flash point and pour point of engine oil as the quality properties of engine oil has been studied and compared. The samples of two concentrations 0.1 and 0.2 wt% with using planetary ball mill were made. The obtained results show that MWCNTs in all cases, which have been evaluated, had better functionality with respect to vanadium oxide nanotubes. In the 0.1 wt% concentration, flash point of MWCNTs/oil and VONTs/oil increased about 9.3% and 5.8% respectively. In addition, thermal conductivity of them increased 13.2% and 10.2% respectively.

Superparamagnetic single phase zinc ferrite nanoparticles have been prepared by coprecipitation method at 20 °C without any subsequent calcination. The composition, crystallite size, microstructure and magnetic properties of the prepared nanoparticles were investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transmission infrared spectrum (FTIR) and vibrating sample magnetometer (VSM). The XRD pattern proved that the nanoparticles were single phase cubic spinel ZnFe2O4 with crystallite size of 5nm. The magnetic measurement showed that the as-prepared nanoparticles of zinc ferrite were superparamagnet at room temperature.

The discharge of lead containing effluents into the environment and water bodies is harmful for the human, animals, aquatic flora and fauna. Herein, a novel surface engineered magnetic nanoparticle for removing Pb2+ ions was studied. After surface modification of the magnetite by 3-amino-propyltriethoxysilane (APTES) magnetic nanoparticles with covalently linked porphyrins were synthesized. Two atropisomers of meso-tetrakis(2-carboxy-4-nonylphenyl) porphyrin (TCNP) were tested to analyze the atropisomeric effect on lead uptake. For characterize the synthesized nanosorbents methods like: Transform Infrared Spectroscopy, X-ray diffraction, Transmission Electron Microscopy and Thermo-Gravimetric Analysis were used. The effects of pH, contact time, sorbent dosage and some co-existing cations were investigated. Regeneration of lead adsorbed material could be possible and the modified magnetic nanoparticles exhibited good reusability. The use of such a system can provide fast and efficient removal of the lead ion by using an external magnetic field. The competitive adsorption tests showed good adsorption selectivity for lead ion.

This paper reports the synthesis of polypyrrole coated SnO2/ZnOelectrospunnanofibers via vapor phase polymerization method. In order to prepare one dimensional (SnO2- ZnO)/polypyrrole with the core sheath structure, first SnO2-ZnO composite nanofibers were synthesized via electrospinning method followed by adsorption of Fe3+ on the surface of the SnO2-ZnO nanofibers and finally pyrrole was polymerized on the surface of the fibers. The results of simultaneous thermal analysis (STA), Xray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of the nanofibers confirmed the success of synthesis of (SnO2-ZnO)/polypyrrole core sheath compound.

Two simple protocols for the synthesis of tetrahydrobenzo[a]xanthenes-11-ones using nano silica phosphoric acid are reported. Short reaction times, high yields, reusability of catalyst and easy workup are some advantages of these protocols.

In this work, zeolite NaY was prepared by hydrothermal method. Then, silver ions were replaced in the zeolite NaY with silver nitrate (AgNO3) solution via using ion exchange (IE) method. The Manganese dioxide (MnO2) nanoparticles (9.3 and 15.8 wt %) for guest were deposited in the zeolite AgY(host) structure with Mn(NO3)2 aqueous and KMnO4 solutions by confined space synthesis (CSS) method. Synthesized samples were studied and characterized via XRD, SEM/EDAX, FTIR, AAS and N2-BET techniques. The desulfurization and elimination reaction of 2- chloroethyl phenyl sulfide (2-CEPS) and DEPPT (O, S-diethyl phenyl phosphonothioate) have been investigated by 15.8 wt% Nano MnO2/Zeolite AgY composite and MnO2 nanoparticles catalysts and via GC, GC-MS and 31PNMR.

In this research, a sol gel autocaombustion route has been proposed to synthesize alumina-zirconia composite powders, using ammonium bicarbonate as a new fuel. Then the effect of calcination temperature on phase transformation and crystallite sizes was investigated. To characterize the products XRD, TEM and BET analyses were used. XRD patterns of as-synthesized powder and calcined powders at 1100 ◦C and 1200 ◦C showed t-ZrO2 phase with small crystallite sizes (<14 nm). As-synthesized powders were also sintered at 1300 ◦C and the particle sizes after calcination were 14.90 nm and 50 nm for ZrO2 and Al2O3 phases, respectively as calculated from XRD and the transformation of t-ZrO2 to m-ZrO2 started at 1300 ◦C. TEM micrograph of as-synthesized powder revealed nanosize spherical particles of about 8 nm.

Aluminum sulfate nano structures have been prepared by solution combustion synthesis using aluminum nitrate nonahydrate (Al(NO3)3.9H2O) and ammonium sulfate ((NH4)2SO4). The resultant aluminum sulfate nano structures were calcined at different temperatures to study thermal decomposition of aluminum sulfate. The crystallinity and phase of the as-synthesized and calcined samples were characterized by both X- ray diffraction and FTIR measurements. These two analyses determined the temperature at which the aluminum sulfate is converted to γ-alumina nano particles. The specific surface area and pore size distribution for γ-alumina nano particles were determined by BET measurement. TEM measurement confirmed the size of the particles obtained by XRD and BET analyses.

Thin films of SnO2 nanowires were successfully prepared by using chemical vapor deposition (CVD) process on quartz substrates. Afterwards, a thin layer of palladium (Pd) as a catalyst was coated on top of nanowires. For the deposition of Pd, a simple and low cost technique of spray pyrolysis was employed, which caused an intensive enhancement on the sensing response of fabricated sensors. Prepared sensor devices were exposed to liquid petroleum gas (LPG) and vapor of ethanol (C2H5OH). Results indicate that SnO2 nanowires sensors coated with Pd as a catalyst show decreasing in response time (~40s) to 1000ppm of LPG at a relatively low operating temperature (200oC). SnO2 /Pd nanowire devices show gas sensing response time and recovery time as short as 50s and 10s respectively with a high sensitivity value of ~120 for C2H5OH, that is remarkable in comparison with other reports.

A comprehensive study of Schottky barrier MOSFET (SBMOSFET) scaling issue is performed to determine the role of wafer orientation and structural parameters on the performance of this device within Non-equilibrium Green's Function formalism. Quantum confinement increases the effective Schottky barrier height (SBH). (100) orientation provides lower effective Schottky barrier height in comparison with (110) and (111) wafers. As the channel length of ultra thin body SBMOSFET scales down to nanoscale regime, especially for high effective SBHs, quantum confinement is created along the channel and current propagates through discrete resonance states. We have studied the possibility of resonant tunneling in SBMOSFET. Resonant tunneling for (110) and (111) orientations appear at higher gate voltages.

Linear–dendrite copolymers containing hyper branched poly(citric acid) and linear poly(ethylene glycol) blocks PCA–PEG–PCA are promising nonmaterial to use in nanomedicine. To investigate their potential application in biological systems (especially for drug carries) ONIOM2 calculations were applied to study the nature of particular interactions between drug and the polymeric nanoparticles. Binding energy (BE) and interaction energy (IE) analysis of these complexes allowed the fundamental features of the drug- the Linear– dendritic copolymers interactions to be assessed based on ONIOM method. The results show that they have weak interaction and these complexes have relatively low stability and so PCA-PEG-PCA copolymers can use to as drug delivery.

A simple and efficient one-pot three-component synthesis of the biologically important spirooxindole-4H-pyrans was carried out by the reaction of isatin, activated methylene reagents, and 4- hydroxycoumarin in aqueous medium. SBA-Pr-NH2 was found to be an efficient heterogeneous nanoporous solid basic catalyst (pore size of 6 nm) which can be easily handled and removed from the reaction mixture by simple filtration. This method is of great value because of its environmentally benign character, high yield processing, and easy handling. The biological activity of target compounds was screened by evaluation of their urease enzyme inhibition.

In this study, silver nanoparticles were synthesized by chemical reduction method at different concentrations of Ag colloid in the range of 500-16000 ppm. Nanoparticles were deposited by spin coating method on pre-etched glass and Si substrates. Structural, optical and electrical properties of the samples were studied using Scanning Electron Microscopy equipped with EDAX, UV-Vis spectrophotometry and four-point probe. Particles size was determined according SEM results and was compared for two different substrates.

In this paper, CuO nanoparticles have been synthesized via solidstate thermal decomposition using copper(II) Schiff base complexes as new precursors at 600ºC under air atmosphere for 3 h. Surface morphology of the products were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM).

his paper presents results of a numerical study of mixed convection and entropy generation of Cu–water nanofluid in a square ventilating cavity at different inclination angles. Except a piece of bottom wall with a uniform heat flux, all of the cavity walls are insulated. The inlet port is placed at the bottom of the left wall and the outlet port is positioned at the top of the right wall. Entropy generation, Bejan number, average Nusselt number and heat source temperature have been investigated for Richardson numbers between 0.1 and 10, Reynolds numbers in the range of 1 and 300, solid volume fractions between 0 and 0.06 and cavity inclination angles between 􀔟90o and 90o. The results show that the average Nusselt number increases with increasing Richardson number for cavity inclination angle of 30o, 60o and 90o but decreases with increasing Richardson number for inclination angle of 30o, 60o and 90o. Total entropy generation and entropy generation due to heat transfer decreases with increasing Richardson and Reynolds numbers, but the Bejan number increases with increasing Reynolds and Richardson numbers.

Copper matrix composite reinforced by 1wt.% TiB2 particles was prepared using in situ reaction of Cu-1.4wt.% Ti and Cu-0.7wt.% B by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºC. High-resolution transmission electron microscopy (HRTEM) characterization showed that primary TiB2 particles were formed in liquid copper. Heat treatment of as-solidified samples led to the formation of secondary TiB2 particles via spinodal decomposition of titanium-rich zone inside the grains. Mechanical properties (after 50% reduction in area) as well as electrical conductivity of composite were evaluated after heat treatment and were compared with those of pure copper. The results indicated that, due to the formation of secondary TiB2 particles in the matrix, electrical conductivity increased along with hardness up to 10 hrs of heat treatment and reached 65% IACS and 155 HV, respectively. Moreover, the maximum ultimate (i.e. 580 MPa) and yield (i.e. 555 MPa) strengths of composite were achieved at this time.

Hard magnetic SrFe12O19 (SrM) nanoparticles were synthesized by a facile sonochemical reaction. The magnetic nanoparticles were then added to acrylonitrile-butadiene-styrene, polystyrene, polycarbonate, and poly sulfone to make magnetic nanocomposites. The magnetic properties of the samples were also investigated using an alternating gradient force magnetometer. The strontium ferrite nanoparticles exhibited ferrimagnetic behaviour at room temperature, with a saturation magnetization of 39 emu/g and a coercivity of 5070 Oe. The distribution of the SrFe12O19 nanoparticles into the polymeric matrixes increases the coercivity.