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The metal oxide semiconductor gas sensor technology is robust and has quick response times. In this work, aluminium and tin codoped zinc oxide (ASZO) thin films were synthesized by a sol-gel dip-coating process as sensors for the greenhouse gas nitrogen dioxide (NO 2). The prepared ASZO thin films were characterized using such techniques as X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and photoluminescence (PL) emission studies in order to analyze the elemental confirmation, particle size, surface roughness and optical emission properties, respectively. The XRD data reveals the hexagonal structure of ASZO and that the preferential orientation is along 2θ = 36.19 •. SEM images of the ASZO thin film exhibit rod-like formations of ASZO on the substrate. The ASZO films show enhanced sensing behaviour, sensing NO 2 gas even at 2 ppm at an operating temperature of 170 • C. The response and recovery times were determined to be 30 and 20 s, respectively.

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The present study portrays the development of lightweight epoxy laminates filled with boron carbide (B4C) and lead (Pb) particles through a novel layered molding and curing route. Six different laminates of single and tri-layers were prepared with varying compositions and were subjected to thermal, radiation shielding, and dielectric studies. Radiation shielding test were done using a narrow beam setup with six different sources such as Cobalt-57 (Co57-122 keV), Barium-133 (Ba133-356 keV), Sodium-22 (Na22-511 and 1275 keV), Cesium-137 (Cs137-662 keV), Manganese-54 (Mn54-840 keV), and Cobalt-60 (Co60-1170 and 1330 keV). The dielectric studies were done to understand the dielectric constant, dielectric loss factor, and AC conductivity at different temperature and frequency ranges. From the characterizations, it was found that the thermal stability of the single-layered sample increased with respect to the addition of B4C and Pb particles, which may be due to the thermally stable nature of the particles. The radiation shielding study of the samples witnessed the superior characteristics and radiation shielding ability of sample D (40% Pb) and sample E with Pb cladding at incident gamma radiation energy of 662 keV. The dielectric constant of the samples increased significantly at higher temperatures and the dielectric loss factor increased with an increase in temperature and decreased with an increase in frequency. The AC conductivity of the samples increased with respect to an increase in temperature and frequency.

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