No abstract

Nano aluminum oxide was prepared by the combustion method using aluminum nitrate as the oxidizer and urea as a fuel. Characterization of synthesized materials was performed using SEM (scanning electron microscope), powder XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), and TEM (transmission electron microscope). Al-Mg/Al2O3 (2, 4, 6, and 8 wt%) metal matrix nanocomposites were prepared by liquid metallurgy route-vertex technique. The homogeneous dispersion of nano Al2O3 particles in Al-Mg/Al2O3 metal matrix nanocomposites (MMNCs) was revealed from the field emission SEM analysis. The reinforcement particles present in the matrix were analyzed through energy-dispersive X-ray spectroscopy method. The properties (corrosion and mechanical) of the fabricated composites were evaluated. The mechanical and corrosion properties of the prepared nanocomposites initially increased and then decreased with the addition of nano Al2O3 particles in Al-Mg Matrix. The studies show that, the presence of 6 wt% of nano Al2O3 particles in the matrix improved the properties of other combinations of nano Al2O3 in the Al-Mg matrix material. Further, the Al-Mg/Al2O3 (6 wt%) MMNCs are joined by friction stir welding and evaluated for microstructural, mechanical, and corrosion properties. Al-Mg/Al2O3 MMNCs may find applications in the marine field. The response surface method (RSM) was used for the optimization of tensile strength, Young’s modulus, and microhardness of the synthesized material which resulted in a 95% of statistical confidence level. Artificial neural network (ANN) analysis was also carried out which perfectly predicted these two properties. The ANN model is optimized to obtain 99.9% accurate predictions by changing the number of neurons in the hidden layer.

No abstract

No abstract

We report on the fabrication and electrical characterization of aligned multiwall nanotubes (MWNTs) grown on a four-probe patterned catalyst layer. This structure has been designed to directly measure the electrical property of as-grown MWNTs. The temperature-resistance results show that the aligned MWNTs are semiconducting in directions perpendicular to the tube axis and follow the three-dimentional hopping conduction mechanism. Effects of oxygen plasma on the characteristics of the MWNTs are also investigated. Raman spectroscopy results indicate that oxygen plasma treatments can be used to reduce the carbonaceous material in the film. As the exposure time of oxygen plasma increases, the resistance of the aligned MWNTs increases mainly due to the suppression of current conduction through carbonaceous materials. These results suggest that oxygen plasma treatment is effective in improving the film quality of as-grown MWNTs.

No abstract

Woven glass fiber reinforced with epoxy matrix composites are manufactured considering different glass/epoxy proportions and vibration analyses of the laminated composite plates subjected to free vibrations have been examined. The tensile and flexural strength of composites were evaluated by following ASTM standards. Free vibration of the composite specimen characteristics is studied using a Fast Fourier Transform analyzer, accelerometer using impact hammer excitation. The fast response functions are studied in order to clearly understand the vibration characteristics of the specimens. The experimentally obtained results of the rectangular composite plates are compared with the analytical results obtained from Nastran. The results showed a good agreement. It was observed that as the number of layers of the composite specimen increased, the frequency response also increased.

The wear characteristics of Aluminium AA 5083/SiC/Fly ash functional composites under different load conditions are an important aspect to assess the inoculation of fly ash for enhancing the functionality of the Aluminium composites with respect to its tribological behaviour and its influence on wear. Current work is majorly aimed at the development of AA 5083/SiC functional composites inoculated with fly ash using stir casting method for different blends of the reinforcements (2.5, 5 & 7.5 wt. %). Wear characteristics of these fabricated composites has been investigated considering various process parameters and influence of each parameter on wear rate was discussed. Based on different wear regimes obtained after characterization of the samples at different load conditions, Analysis of Variance (ANOVA) is carried out for each blend of the samples. The results have given sufficient substantiation to the fact that wear rate decreases with the inoculation. Results conferred that micro segregation (coring) of SiC and uniform dispersion of fly ash in the matrix enhances its tribological characteristics.