[1] Flux of micrometeorites is estimated by using cosmic spherule counts from a seafloor area of 2.50 m 2 from the Indian Ocean. The spherules are recovered from sediment samples in close-spaced locations from the Indian Ocean after sieving 293 kg of sediment. The terrestrial age of the spherules has a range of 0-~50,000 years. The spherules have a size range of 57-750 μm (average size 265 ± 92 μm). The diameter of the spherules increases from scoriaceous-barred-cryptocrystalline-glassy types. The time-averaged flux of the spherules is 160 t/yr, a sizeable mass (>60%) resides in the >300 μm fraction; the slope of distribution is similar to that of Deep-Sea Spherules but significantly different from other collections which have lower average diameters. It is observed here, a significant population of cosmic dust resides in the larger sizes which can be recovered by sampling large areas in time and space. The spherule textures are similar to that of unbiased collections from the polar regions, indicating that the textural types of cosmic dust that have been raining on the Earth during the last 50 kyr have been constant regardless of size. Major element chemistry of a majority of the spherules show elemental ratios that are close to a CM or CI chondritic parent body; a single spherule (0.2% of the population) suggests an achondritic parent body. Unbiased collections spanning large areas temporally and spatially enlarge the inventory of the Earth-crossing meteoroid complex and provide valuable inputs for models on cosmic dust accretion.

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Specifically for the optoelectronics field, it is always a provocative task for researchers to fabricate a device that can endure diverse extreme conditions without losing its fundamental properties. Metal dichalcogenides have stimulated influential research inquisitively due to the noteworthy optoelectronic properties and device applications designed for extreme environmental circumstances. Among metal dichalcogenides, SnSe2 is an exceptionally studied material due to its extraordinary photosensing ability. In the present article, exploration of the photoresponse nature of the vapor-phase-grown SnSe2 single crystal is elaborated comprehensively. The stoichiometric purity of constituents was verified by the energy-dispersive X-ray analysis (EDAX). The X-ray diffraction (XRD) pattern unveiled a highly crystalline hexagonal lattice structure. A surface morphological analysis is carried out by optical and scanning electron microscopy (SEM) experiments in which layered growth mechanism and randomly oriented hexagonal sheets are observed. Additionally, crystalline nanoflakes are observed in high-resolution transmission electron microscopy (HR-TEM), wherein the interlayer lattice spacing is found to be 0.65 nm. The first-order temperature coefficient and anharmonicity constant are determined from the dependence of Raman mode on low temperatures. Afterward, the photodetection properties are inspected for distinct conditions such as perpendicular and parallel to the c-axis, varied intensity of mono- and polychromatic illumination with different externally applied biases to the detector, and cryogenic temperatures down to 10 K. To the best of our knowledge, sensor properties at 10 K are being reported for the first time in this article. As per investigation, the remarkable properties of SnSe2 single crystals such as reproducibility, steadiness, self-biased nature, ability to withstand and responding to the illumination even at a low temperature of 10 K make them a strong candidate for future optoelectronic switching applications for cryotronics.

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Aluminising of 9Cr steel substrates followed by heat treatment has been attempted to generate Al 2 O 3 films along with Fe-Al diffusion zone at the coating/substrate interface. Effect of glow discharge plasma processing on the phase and microstructure of resultant alumina films in comparison with thermally processed samples has been reported. The thermal and plasma treated samples were characterised using X-ray diffraction, scanning electron microscopyenergy dispersive X-ray spectroscopy, electron probe microanalysis, X-ray photoelectron spectroscopy (XPS) and nanoindentation techniques. X-ray diffraction and XPS studies revealed c-Al 2 O 3 phase in both thermal and plasma processed samples. The XPS data indicated higher binding energies in plasma processed Al 2 O 3 films as compared to thermally processed Al 2 O 3 films. Scanning electron microscopy observations revealed cracks in thermally grown Al 2 O 3 films while the same was not observed in plasma processed films. The EDX analysis revealed Fe(Al) diffusion layer of y3 mm in plasma processed films while the same was not observed in thermally treated samples. Nanoindentation tests on plasma grown alumina films indicated 16?96 GPa hardness while hardness for thermally grown alumina films was found to be 9?95 GPa. The role of plasma in generating a crack free alumina film has been discussed.

We present the development of a cerium-doped lanthanum bromide (LaBr 3 : Ce) gamma-ray spectrometer (GRS) with the primary objective of determining the abundance and distribution of Th, U, K, and other major elements, including Fe on the entire planetary surface by measuring gamma-ray signals produced by radioactive decay, neutron inelastic scattering and neutron capture reactions in the energy region 0.03-8 MeV. The energy resolution of the LaBr 3 : Ce GRS developed in-house using front-end and processing electronics at 511 and 1274 keV is estimated to be 4.1% and 2.5% respectively. The intrinsic activity count rate for our 3  3 LaBr 3 : Ce GRS is ~61 counts s -1 (i.e. ~0.18 counts s -1 cm -3 ) for the 40 K energy window (1400-1520 keV) and ~3.4 counts s -1 for the 232 Th (2550-2700 keV) energy window. Although this large intrinsic activity of the LaBr 3 : Ce crystal inhibits estimation of the concentrations of Th and K, our attempts using a NaI(Tl) GRS (with electronics developed in-house) were more successful. The Th concentration of US-110 was estimated to be ~11.4 ppm and is within 14% of the 13.2 ppm value determined using a HPGe GRS. The K concentration of US-110 was estimated to be 0.87% and is within ~10% of the 0.78% value determined independently using a HPGe GRS.