Enhanced optical absorption in semiconductor nanoparticles enabled by nearfield dielectric scattering

The optical absorption of semiconducfing AgBr nanocubes is significantly increased by up to 5 times in the measured spectral range when they are bonded to the surface of dielectric SiO2 nanospheres through electrostatic interaction.The absorption enhancement factor depends on the wavelength and the size of the SiO2 nanoparticles (NPs).Finite-difference time-domain calculations provide the nearfield intensity mapping of a heterostructure that is composed of a AgBr nanocube in close contact with a SiO2 nanosphere.The electric-field distributions indicate the field enhancement near the SiOdAgBr interface due to light scattering and absorption enhancement in the AgBr nanocube,implying that the enhanced scattering nearfield increases the absorption cross section of the AgBr nanocube.The absorption cross-section spectra calculated using Mie theory agree with the experimental observations.This discovery sheds light on the utilization of dielectric spherical particles to increase the absorption in semiconductor NPs,thus improving the light-harvesting efficiency for solar-energy conversion.     

Nuclear data sheets for A = 143

Level schemes and decay characteristics are presented for all nuclei with mass number 143. Experimental data, adopted values, comparisons with theory, and arguments for spin and parity assignments are given. The adopted level schemes and decay properties are based on data received before January 1, 1974.     

Nuclear data sheets for A = 82

Level schemes and decay characteristics are presented for all nuclei with mass number 82. Experimental data, adopted values, comparisons with theory, and arguments for spin and parity assignments are given.The adopted level schemes and decay properties are based on data received before November 1, 1974.     

Environmental impacts of remediation of a trichloroethene-contaminated site: life cycle assessment of remediation alternatives

The environmental impacts of remediation of a chloroethene-contaminated site were evaluated using life cycle assessment (LCA). The compared remediation options are (i) in situ bioremediation by enhanced reductive dechlorination (ERD), (ii) in situ thermal desorption (ISTD), and (iii) excavation of the contaminated soil followed by off-site treatment and disposal. The results showed that choosing the ERD option will reduce the life-cycle impacts of remediation remarkably compared to choosing either ISTD or excavation, which are more energy-demanding. In addition to the secondary impacts of remediation, this study includes assessment of local toxic impacts (the primary impact) related to the on-site contaminant leaching to groundwater and subsequent human exposure via drinking water. The primary human toxic impacts were high for ERD due to the formation and leaching of chlorinated degradation products, especially vinyl chloride during remediation. However, the secondary human toxic impacts of ISTD and excavation are likely to be even higher, particularly due to upstream impacts from steel production. The newly launched model, USEtox, was applied for characterization of primary and secondary toxic impacts and combined with a site-dependent fate model of the leaching of chlorinated ethenes from the fractured clay till site.     

Chemical properties of surimi seafood nutrified with ω-3 rich oils

Surimi-based seafood products are widely accepted and enjoyed worldwide. The US consumption increased in 1980s; however, it leveled thereafter. Food products nutrified with ω-3 polyunsaturated fatty acids (PUFAs) are in increasing demand due to demonstrated health benefits. Currently, surimi seafood is not nutrified with ω-3 PUFAs. In the present study, surimi seafood was nutritionally-enhanced with ω-3 PUFAs-rich oils (flaxseed, algae, menhaden, krill, and blend). The objectives were (1) chemical characterization of FA composition and oxidation, and (2) determination of physicochemical properties (colour and texture) of the nutritionally-enhanced surimi seafood. Oil addition resulted in increased (P < 0.05) concentration of total ω-3 FAs in surimi seafood; however, the concentration of α-linolenic (ALA, 18:3ω-3), eicosapentaenoic (EPA, 20:5ω-3) and docosahexaenoic (DHA, 22:6ω-3) acids depended on which oil was added. Although the ω-3 PUFAs nutrification resulted in increased (P < 0.05) susceptibility of surimi seafood to lipid oxidation, it was within ranges acceptable to consumers. Texture analysis (texture profile analysis, Kramer shear and torsion test) showed that ω-3 PUFAs nutrification did not affect texture. Colour properties of ω-3 PUFAs nutrified surimi seafood were generally improved except when krill oil or blend was added. This study demonstrates that nutritional value of surimi seafood can be enhanced with concurrent improvement of colour and without affecting texture.