Effect Of MgO Nanoparticles Research Articles

Effect of MgO Nanoparticles on the AC Breakdown Voltage, Partial Discharge Activity, and Electrostatic Charging Tendency of Natural Ester

Effect of MgO Nanoparticles on the AC Breakdown Voltage, Partial Discharge Activity, and Electrostatic Charging Tendency of Natural Ester

Effects of MgO nano particles on the mechanical properties and corrosion behavior of Mg–Zn–Ca alloy

An as-extruded Mg–3Zn-0.2Ca-0.3MgO (wt.%, ZX0.3) composite with good mechanical properties and high corrosion resistance was designed and fabricated by hot extrusion based on the requirements of biodegradable Mg alloys. The results revealed that the average grain size was reduced about 50% to 1.9 μm and the yield stress was increased about 34%–269 MPa after adding MgO to Mg–3Zn-0.2Ca (wt.%, ZX) alloy. Theoretical calculation and experimental results showed that the grain boundary strengthening and Orowan strengthening were the main strengthening mechanisms (>95%) of the composite, while the addition of MgO NPs and the increasing of basal texture were harmful to the plastic of ZX0.3 composite. However, the activation of prismatic <a> dislocations and pyramidal <c> dislocations would reduce the negative impact of them. The corrosion test results revealed that in ZX0.3 composite, MgO nanoparticles (NPs) not only promoted the formation of the Mg(OH)2 layer, but also effectively barricaded the cracks extension in corrosion products layer, making the corrosion product layer much denser and durable. The corrosion rate of ZX0.3 composite was reduced by 30% to 0.79 mm/yr compared with that of ZX alloy. In addition, the reduced corrosion rate of matrix could provide a more suitable environment for cell adhesion and differentiation, which results in better cytocompatibility of the ZX0.3 compared with ZX alloy.

Effects of MgO nanoparticles on dynamic shear modulus of loess subjected to freeze-thaw cycles

This study evaluated the utilization of nano-MgO in problematic loess to enhance the dynamic performance and freeze-thaw resistance. To address these issues, samples of different blend ratios, with or without freezing-thawing, were prepared, and their dynamic modulus were examined by a series of dynamic triaxial tests. The results indicate that an addition of 2.5% nano-MgO improved the maximum shear modulus of pre- and post-freezing-thawing samples by 75.26% and 184.9% on average. Significant detrimental effects of freezing-thawing and water content were also observed. While it is found these detrimental effects could be alleviated with the addition of nano-MgO. Novel models for dynamic modulus of nano-MgO treated loess were accordingly proposed towards infrastructure design in cold regions. Additionally, the stabilizing mechanism of nano-MgO was explored by nuclear magnetic resonance tests. The results indicate that the water-absorbing effect of nano-MgO turns free water into bound water, therefore, resulting in significant improvements of dynamic performance and freeze-thaw resistance. This study provides conclusive evidence that nano-MgO is a high-function additive for the stabilization of loess soil subjected to freezing-thawing environment.

Effect of Nano-MgO, Biochar and Humic Acid on Boron Stabilization in Soil in Bath and Leaching Columns

ABSTRACT In this study, batch and column experiments were conducted to investigate the effect of MgO nanoparticles (NPs), humic acid and biochar for boron (B) immobilization in contaminated soil. Results showed that the fate and mobility of B was controlled by adsorption reactions and the amount of B adsorption increased in soil treated with MgO at 2% wt while the amount of B adsorption declined in presence of humic acid and biochar treatments. Maximum adsorption on the basis of isothermal curves was 85.9, 94.0, 50.9 and 83.6 mg kg−1 for control, MgO, humic acid and biochar treatments, respectively. Fractionation of isotherm experiments in soil treated by MgO NPs, humic acid and biochar indicated that compared to control soil the exchangeable fractions decreased in all treatment at initial B concentration of 2 mg L−1 while an increase was observed at initial B concentration of 10 mg L−1. Boron in organic fraction has also enhanced by biochar and humic acid application while this fraction reduced in presence of MgO NPs. Residual fraction showed an increase in presence of MgO NPs and biochar at low initial concentration of B while it reduced in soil treated with humic acid. Column breakthrough testing indicated the outlet concentration becomes equal to the inlet concentration after pore volumes of 4, 26, 3 and 1 for soil control, soils treated by MgO NPs, humic acid and biochar, respectively.

The Effect of MGO Nanoparticles on Structure and optical Properties of PVA-PAAm Blend

The films of PVA-PAAm-MgO were prepared with various content (0, 0.02, 0.04) of 30 nm particle size MgO by casting solution method. The structure of PVA-PAAm-MgO composite was examined via FT-IR to determine the activation groups, while the diffusion of MgO nanoparticle inside the prepare blend and the homogeneity were examined using the optical microscope. UV-Visible spectrophotometer that used to recording the transmittance spectra in the range of 300-900 nm. The transmittance decreased with the increasing of MgO nanoparticles content in the PVA-PAAm-MgO composite, while the absorbance increased. The optical constants are determined and the optical energy gap decreased with the increasing of MgO nanoparticle content in the PVA-PAAm-MgO composite.

Investigating the MgO nanoparticles and trypsin interaction through spectroscopic methods

The aim of this work was to study the effect of MgO nanoparticles (NPs) on both the structure and activity of the trypsin enzyme at pH 8.0 using UV–Vis spectroscopy, fluorescence spectroscopy, and enzyme activity assay techniques. The examination of the enzyme activity revealed that the MgO-NPs tended to increase the latter. Moreover, it was found that the rise in the trypsin UV–Vis absorption could be due to the formation of the trypsin–MgO-NPs complexes. The Stern–Volmer constant was reduced as the temperature was increased from 298 to 308 K, thereby indicating that the MgO-NPs caused the intrinsic fluorescence quench of trypsin via the static quenching mechanism. Furthermore, the detailed analysis of thermodynamic parameters for our fluorescence data revealed the spontaneous binding of trypsin to the MgO-NPs, with the hydrogen bonding and van der Waals interactions being only the main physical basis of the trypsin–MgO-NPs coupling.

Optimization of the Depth of Penetration by Welding Input Parameters in SAW Process Using Response Surface Methodology

The aim of this paper is to optimize the depth of penetration with regard to the effect of MgO nanoparticles and welding input parameters. For this purpose, response surface methodology (RSM) with central composite rotatable design (CCRD) was used. The welding current, arc voltage, nozzle-to-plate distance, welding speed, and thickness of MgO nanoparticles were determined as the factors, and depth of penetration was considered as the response. Quadratic polynomial model was used for determining the relationship between the response and factors. A reduced model was obtained from the data which the values of R 2, R 2 (pred), and R 2 (adj) of this model were 92.05, 69.05, and 86.31 pct, respectively. Thus, this model was suitable, and it was used to determine the optimum levels of factors. The results show that the welding current, arc voltage, and nozzle-to-plate distance factors should be adjusted in high level, and welding speed and thickness of MgO nanoparticles factors should be adjusted in low level.

Microstructure, electrical and mechanical properties of MgO nanoparticles-reinforced porous PZT 95/5 ferroelectric ceramics

Porous Pb (Zr0.95Ti0.05) O3/xMgO (PZT/MgO, x=0, 0.1, 0.2, 0.5 and 1.0 wt%) ferroelectric ceramics were prepared with MgO nanoparticles as reinforcing phase. The effects of MgO nanoparticles on the phase, microstructure, electrical and mechanical properties of as-prepared ceramics were investigated. The results show that the grain size is reduced obviously when increasing the amount of MgO. Compared with pure porous PZT, TC of MgO-added PZT ceramics shifts to higher temperature. Moreover, dielectric, ferroelectric and piezoelectric properties show no much degradation. Further, PZT/MgO ceramics possess enhanced mechanical properties compared to pure porous PZT ceramics, the largest increment of the fracture toughness and hardness being 31.3% and 19.8%, respectively. The optimal electrical and mechanical properties are obtained with the addition of less than 0.5 wt% MgO nanoparticles.

Effect of MgO Nanoparticles on Properties of PZT Ceramics

In this research, the effect of MgO nanoparticles doping on electrical and mechanical properties of PZT ceramics were studies. PZT/MgO doped (0–2 vol%) ceramics were prepared by conventional mixed oxide method and sintered at 1200°C for 2 h. Phase formation and microstructure were examined by X-ray diffraction technique (XRD) and scanning electron microscope (SEM). An impedance analyzer was also used to measure the dielectric constant (ϵr) at room temperature. The microhardness was determined using a Vickers indentation technique. The results found that the average grain size decrease with the addition of MgO nanoparticles. The dielectric constant and microhardness is only improved at 0.1 vol% MgO doping.

Effect of MgO nanoparticles on ionic conductivity and electrochemical properties of nanocomposite polymer electrolyte

This paper analyzes the comparison between the performances and morphologies of the PMMA gel and composite electrolyte membrane with nanosized MgO particles. These polymer electrolytes were studied in detailed using XRD, DSC, SEM and AC impedance analysis. The conductivity enhancement has been attributed to the addition of ceramic filler that yields a significant increase of surface to volume ratio related to the decrease in glass transition temperature values in the composite polymer electrolyte. Good interfacial stability at the electrode/electrolyte interface resulted on account of the improved ion dissociation by ceramic filler and a rise in the room temperature conductivity (8.14 × 10 −3 S cm −1) due to the iono-covalent or Lewis acid–base bonds to the ions and ether oxygen base groups was also observed. Further enhancement of conductivity has been observed on MgO surface, as Lewis-acidic sites interact with both PMMA and ClO 4 − ions. The percentage of swelling was found to increase with increasing soaking periods upto 12 h. Beyond that soaking period, it was found that there was a negligible increase in the % of swelling.