We report high-yield and efficient size-controlled syntheses of Chalcopyrite CuInS2nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100°C and times as short as 30 minutes. The nanoparticles sizes were 1.8 nm to 10.8 nm as reaction temperatures were varied from 100°C to 200°C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%). The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by1H NMR using SSP1with 1,2-ethanedithiol and benzyl mercaptan were conducted to elucidate the formation of Chalcopyrite CuInS2nanoparticles.
Titanium dioxide and a 100 W mercury spotlamp were used to photoreduce 100 ppm Hg aqueous mercuric chloride solutions. The solution's basicity and temperature were varied. Two optimum photoreduction conditions were determined: pH 9, 0 °C and pH 11, 40 °C. TiO 2 -assisted photoreduction at these two conditions lowered the concentration of mercury left in the solution to below 200 ppb. Methodology was developed to perform an overall mercury mass balance on the process. The overall mercury balance revealed that more than 97% (average 103% ( 6%) of the mercury removed from solution was deposited as mercury metal on the surface of the TiO 2 for the pH 9, 0 °C treatment conditions. This mercury could be driven off the TiO 2 surface by heating to 100 °C for half of an hour under nitrogen flow. The pH and temperature information under light and dark conditions is consistent with a pH-dependent adsorption of a dissociated mercuric species by hydroxide ions on the TiO 2 surface followed by nucleation of the reduced species. The TiO 2 assisted photoreduction process shows promise for remediation of mercuric waste below the EPA 200 ppb mercury disposal limit as well as the potential for recycling the mercury and TiO 2 catalyst.
Infrared thermal imaging is an evolving approach useful in non-destructive evaluation of materials for industrial and
research purposes. This study investigates the use of this method in combination with multivariate data analysis as an
alternative to chemical etching; a destructive method currently used to recover defaced serial numbers stamped in metal.
This process involves several unique aspects, each of which works to overcome some pertinent challenges associated
with the recovery of defaced serial numbers. Infrared thermal imaging of metal surfaces provides thermal images sensitive
to local differences in thermal conductivity of regions of plastic strain existing below a stamped number. These strains are
created from stamping pressures distorting the atomic crystalline structure of the metal and extend to depths beneath the
stamped number. These thermal differences are quite small and thus not readily visible from the raw thermal images of an
irregular surface created by removing the stamped numbers. As such, further enhancement is usually needed to identify
the subtle variations. The multivariate data analysis method, principal component analysis, is used to enhance these subtle
variations and aid the recovery of the serial numbers. Multiple similarity measures are utilised to match recovered numbers
to several numerical libraries, followed by application of various fusion rules to achieve consensus identification.
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