International Journal of Nanoscience

A method of synthesis is presented for the rapid preparation of copper, copper oxide and mixed copper oxide-copper nanoparticles employing a conventional home microwave oven. The nanoparticles were characterized by SEM, XRD and UV-visible spectroscopy. The size and the composition of the nanoparticles were controlled by the heating time. Cuprous oxide nanoparticles were obtained at short heating times and copper nanoparticles at longer times, while mixed cuprous oxide-copper nanoparticles where obtained in an in between window of time.

Carbon nanotubes (CNTs) are widely explained in fundamental blocks of nanotechnology. These CNTs exhibit much greater tensile strength than steel, even almost similar to copper, but they have higher ability to carry much higher currents, they seem to be a magical material with all these mentioned properties. In this paper, an attempt has been made to incorporate this wonder material, CNT, (with varying percentages) in polymeric matrix (Poly methyl methacrylate (PMMA)) to create a new conductive polymer composite. Various mechanical tests were carried out to evaluate its mechanical properties. The dielectric properties such as dielectric loss and dielectric constant were evaluated with the reference of temperature and frequency. The surface structures were analyzed by Scanning Electron Microscope (SEM).

Various cutting fluids are available in the cutting fluid market to provide good machining performances for metal cutting industries. Incidentally, most of the cutting fluids are synthetic and semisynthetic in nature, and although they are beneficial to the industries, they are posing health and environmental issues. Even if these cutting fluids have sufficient properties required for good machining, the major constraints associated with these fluids are their nature of nonbiodegradability and nonfriendliness to the environment. To overcome these difficulties, intense research is carried out to develop biodegradable and effective cutting fluids. In this research, a novel castor oil-based cutting fluid infused with nanomolybdenum (MoS₂) particles has been developed and its various machining properties have been investigated. Various important cutting parameters like surface roughness, tool life, and cutting force were investigated using this newly developed biodegradable nanofluid as a cutting fluid. Comparative experimental studies have also been undertaken with sunflower oil blend and conventional synthetic oil. Observed results validated that the newly developed castor oil-based nanofluid improves the surface finish and tool life by minimizing the cutting force developed to the considerable extent.

This study is a pilot investigation on the effect of using nanosilica for reinforcing thermoplastic starch-based bioplastic films. An arbitrary 0.2wt.% of nanosilica particles were used to reinforce starch derived bioplastic materials and were further investigated for potential benefits. Nanosilica was extracted from rice husk and was characterized using methods like Fourier transform infrared spectroscopy (FTIR) technique and Brunauer–Emmett–Teller (BET) method. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were used to determine the structure of nanosilica crystals. Scanning electron microscopy (SEM) technique was used to study the surface topography and composition of nano ‘silica. Both raw and reinforced bioplastic films were tested for thermal stability using thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) tests and their performance was compared. Mechanical properties were compared using tensile and tear tests and biodegradability was assessed through enzymatic degradation analysis. It was found that the presence of nanosilica improved the bonding of polymer matrix and in turn increased the thermal stability and tear strength. Nanosilica reinforced matrix resulted in the increase of surface area than raw bioplastic matrix, which lead to high rate of enzymatic reactivity and degradation rate.

Aluminum doped ZnO (${\text{Zn}}_{1-x}$Al_xO, $x=0.01$, 0.02, 0.03 and 0.04) (AZO) nanoparticles were synthesized using citrate-gel method. We report the effect of aluminum doping along with variation of metal to citrate ratio on structural and optical properties of AZO nanoparticles with crystallite size optimization. The X-ray diffraction analysis confirmed Wurtzite crystal structure wherein the crystallite size was within the range of 15–40nm. Optical properties were studied with the help of UV-Visible spectroscopy. Bandgap calculated using Tauc plot is found to be between the range of 2.39–2.75eV and morphological analysis using Scanning Electron Microscopy (SEM) showed the distribution of synthesized material.

Au/GaN/GaAs Schottky diode created by the nitridation of n-GaAs substrate which was exposed to a flow of active nitrogen created by a discharge source with high voltage in ultra-high vacuum with two different thicknesses of GaN layers (0.7nm and 2.2nm), the I–V and capacitance–voltage (C–V) characteristics of the Au/n-GaN/n-GaAs structures were studied for low- and high-frequency at room temperature. The measurements of I–V of the Au/n-GaN/n-GaAs Schottky diode were found to be strongly dependent on bias voltage and nitridation process. The electrical parameters are bound by the thickness of the GaN layer. The capacitance curves depict a behavior indicating the presence of interface state density, especially in the low frequency. The interface states density was calculated using the high- and low-frequency capacitance curves and it has been shown that the interface states density decreases with increasing of nitridation of the GaAs.

Heat transfer through nanotechnology is a current trend which occupies most research areas with improved results. Taking this concept, the present work has been focused on the analysis of quenching effect on steel such as EN 24 and SS 420 with nanoparticles dispersed in quenching medium. Quenching is the process of removing heat from the heat-treated elements which also take part in determining the hardness values depending on the heat transfer rate and quenching time. To ensure the outcome properties, different volume concentrations of nanofluids have been prepared by adding TiO₂ nanoparticles with the average diameter of less than 20nm in synthetic oil. Here, it is planned to have four volume concentrations (0.25g/lit, 0.375g/lit, 0.5g/lit, 0.625g/lit) of nanofluids to be used in the experiment. The materials after facing heat treatment up to 850^∘C (EN 24) and 980^∘C (SS 420), are subjected to quenching by using nanofluid. The work has been carried out by altering the tempering temperature and volume of nanoparticles in the quenching medium. The outcome quality of the product desirably supports our expectations, such as improved hardness and reduced time consumption for quenching. Additionally, the comparative analysis shows an improvement in heat transfer characteristics as well as properties in quenched specimen with nanofluids.

This research work is concerned with synthesis of an innovative type of magneto-rheological fluid (MRFluid) using edible low-cost soya bean oil as a carrier liquid with three different concentrations of electrolytic iron powder as a suspended medium and additives as a commercial grease. The field-dependent rheological properties of MRFluid samples were tested under different magnetic field conditions using rheometer. The results of the field-dependent-rheological properties of the prepared MRFluid samples show good agreement with commercial MRFluid. This directly indicates that the proposed innovative type of MRFluid can be used in automotive suspension systems, dampers, vibration control devices and so forth. Sedimentation test is also carried out in order to know the stability of the MRFluids.

Cheap and efficient dye sensitized solar cells (DSSCs) can be prepared using natural dyes responding in the visible region of solar spectrum. Localized surface plasmon resonance (LSPR) plays a very important role for the improvement in the efficiency of DSSCs by using Plasmonic nanoparticles (PNPs) for exploiting the visible portion of the solar radiation by transferring the energy from dye to PNP. This energy transfers from dye to semiconductor TiO₂ through PNP which increases the overall photo catalytic activity. In the present study, Al-doped TiO₂ photoanodes were prepared via sol–gel route and used for DSSC application. Various natural and synthetic dyes are prepared and the optical transmittance and absorbance of the dyes are measured in the wavelength range of 250–850nm using UV-Vis spectroscopy and they are used in DSSC. Natural dyes extracted from fruits and synthetic dye based on Ruthenium (Ru) metal complex is used as sensitizers. Power conversion efficiency (PCE) of solar cells utilizing different dyes is compared. Out of the various natural dyes, beetroot and strawberry extracts based dyes show good absorbance in the visible range of electromagnetic spectrum. On the other hand, synthetic dyes based on Ru complex show strong absorbance over a wide range of visible spectrum. The absorbance increases with increase in concentration of Ru in ethanol. The extracts of beetroot, strawberry and mixed fruits show a peak in absorbance spectra at 501nm, 416nm and 332nm, respectively, indicating the absorption over a wide range of visible spectrum. Maximum efficiency of DSSCs utilizing PNPs sensitized with beetroot and strawberry dyes are found to be 1.5% and 1.3%, respectively.

During the workover treatment process, poorly compatible workover fluids infiltrating into reservoir could cause serious formation damage. To tackle the aformentioned issues, in this work, low-damage workover fluid was systematically studied. By investigating reservoir damage mechanisms, chemical property study, compatibility evaluation test and core flow test, we obtain three kinds of workover fluids suitable for different blocks in Nanpu oilfield. Attractively, JRYL workover fluid which contains antiswelling agents can effectively prevent water sensitivity, and the permeability recovery values of JRYL workover fluid to NP1-5 and PG2 core are 95.3% and 86.9%, respectively. JRYD workover fluid which contains antiswelling agents and anti-waterblocking agent can prevent both water sensitivity and water blocking damage, and the permeability recovery value of JRYD workover fluid to NP403X1 core is 89.4%. JRYJ workover fluid suitable for high pressure formation can prevent water sensitivity and water blocking damage, and the permeability recovery value of the JRYJ workover fluid to NP403X1 core is 95.1%. The actual field application in Nanpu oilfield indicates that these workover fluids can not only reduce the oil well recovery time after workover treatment, but also increase production recovery rate. These results display great potential to efficiently develop low permeability reservoirs.