International Journal of Nanoscience

Magnetic iron oxide nanoparticles are promising material for various biological applications. In the recent decades, magnetic iron oxide nanoparticles (MNPs) have great attention in biomedical applications such as drug delivery, magnetic resonance imaging (MRI) and magnetic fluid hyperthermia (MFH). This review focuses on the colloidal stability and monodispersity properties of MNPs, which pay more attention toward biomedical applications. The simplest and the most promising method for the synthesis of MNPs is co-precipitation. The biocompatible MNPs are more interested in MRI application. This review also apportions synthesis, characterization and applications of MNP in biological and biomedical as theranostics and imaging.

Rayleigh–Bénard convection in a horizontal layer of nanofluid in the presence of uniform vertical magnetic field is investigated by using Galerkin weighted residuals method. The model used for the nanofluid describes the effects of Brownian motion and thermophoresis. Linear stability theory based upon normal mode analysis is employed to find expressions for Rayleigh number and critical Rayleigh number. The boundaries are considered to be free–free, rigid–rigid and rigid–free. The influence of magnetic field on the stability is investigated and it is found that magnetic field stabilizes the fluid layer. It is also observed that the system is more stable in the case of rigid–rigid boundaries and least stable in case of free–free boundaries. The expression for Rayleigh number for oscillatory convection has also been derived for free–free boundaries.

The preparation of high-impact polypropylene nanocomposites with different organo-montmorillonite (O-MMT) contents by means of meltprocessing was investigated. The nanocomposite properties were evaluated by transmission electron microscopy (TEM), flexural modulus, izod impact strength, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was noticed that the PP/O-MMT nanocomposites properties were affected by clay content. Exceptional improvements in impact strength were obtained (maximum of 185%) by the use of low O-MMT content. The results showed that higher enhancement on mechanical/thermal properties was obtained by 3 wt.% of O-MMT instead of higher quantities.

Full adder is the basic block of arithmetic circuit found in microcontroller and microprocessor inside arithmetic and logic unit (ALU). Improving the performance of the adder is essential for upgrading the performance of digital electronics circuit where adder is employed. In this paper, a single bit full adder circuit has been designed with the help of double gate (MOSFET), the used parameters value has been varied significantly for improving the performance of full adder circuit. Double gate transistor circuit considers as a promising candidate for low power application domain as well as used in radio frequency (RF) devices. Multi-threshold CMOS (MTCMOS) is the most used circuit technique to reduce the leakage current in idle circuit. In this paper, different parameters are analyzed on MTCMOS Technique. MTCMOS technique achieves 99.6% reduction of leakage current, active power is reduced by 42.64% and delay is reduced by 71.9% as compared with conventional double gate 14T full adder. Simulation results of double gate full adder have been performed on cadence virtuoso tool with 45 nm technology.

We propose a Ge/Si graded junctionless transistor (JLT) which helps to reduce the band-to-band tunneling current in off-state for highly doped double gate junctionless transistor (DGJLT). In this paper, we show that there is large band-to-band tunneling (BTBT) current in off-state of silicon-channel and germanium-channel DGJLT, which causes increase in the off-state leakage current by several orders. With the help of band-gap engineering, we found that by using Ge/Si graded channel DGJLT off-state band-to-band tunneling current can be reduced. It is also observed that there is large deviation in the off-state leakage current with variation of drain voltage for Si and Ge body DGJLT, which reduces device stability. It is found that in Ge/Si graded DGJLT variation off-state leakage current with drain voltage is controlled. In Si and Ge, DGJLT electrons from the valence band of the channel tunnel to the conduction band of drain leaves holes which causes increased hole concentration in the channel creating parasitic 'BJT'.

The effectiveness of stannum (Sn²⁺) removal from aqueous solution by using magnetic biochar and functionalized multiwalled carbon nanotube (FMWCNT) was investigated. The effect of various factors, namely pH, adsorbent dosage, agitation speed and contact time was statistically studied through analysis of variance (ANOVA). Statistical analysis revealed that the optimum conditions for the highest removal of Sn²⁺ are at pH 5, dosage 0.1 g with agitation speed and time of 100 rpm and 90 min, respectively. At the initial concentration of 0.1 mg/L, the removal efficiency of Sn²⁺ using FMWCNTs was 93% and 85% with magnetic biochar. The Langmuir and Freundlich constant for both FMWCNTs and magnetic biochar were 13.397 L/mg, 18.634 L/mg and 17.719 L/mg, 25.204 L/mg, respectively. Hence, results prove that FMWCNTs are a better adsorbent with a higher adsorption capacity compared to magnetic biochar. Adsorption kinetic obeyed pseudo-second-order.

The present paper discusses the investigation of electronic properties of anthracene-based single electron transistor (SET) operating in coulomb blockade region using Density Functional Theory (DFT) based Atomistix toolkit-Virtual nanolab. The charging energies of anthracene molecule in isolated as well as electrostatic SET environments have been calculated for analyzing the stability of the molecule for different charge states. Study also includes the analysis of SET conductance dependence on source/drain and gate potentials in reference to the charge stability diagram. Our computed charging energies for anthracene in isolated environment are in good agreement with the experimental values and the proposed anthracene SET shows good switching properties in comparison to other acene series SETs.