Growth of mane-like ZnS nanostructures by using a two-heating zone-tube furnace: structural characterization and photoluminescence

We have synthesized ZnS nanowires with mane-like branches by thermal evaporation of ZnS powder on the Au-coated Si(100) substrate using a two-heating zone tube furnace. The ZnS powder and the Si substrate were kept at 1,000 and 850 °C, respectively, in a nitrogen atmosphere during synthesis of the ZnS nanostructures. Field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and photoluminescence (PL) spectroscopy analyses were performed to investigate the structure, morphology and photoluminescence properties of the products. The axial nanowires grow along the [002] direction and have diameters of 100–200 nm, while on the other hand the branch nanowires grow along the [101] direction and their diameters and lengths are 30–50 and 800–100 nm, respectively. The room temperature PL spectrum with a Gaussian fitting exhibits two visible light emission bands centered at around 397 and 458 nm.     

Domestic wastewater treatment as a net energy producer--can this be achieved?

In seeking greater sustainability in water resources management, wastewater is now being considered more as a resource than as a waste-a resource for water, for plant nutrients, and for energy. Energy, the primary focus of this article, can be obtained from wastewater's organic as well as from its thermal content. Also, using wastewater's nitrogen and P nutrients for plant fertilization, rather than wasting them, helps offset the high energy cost of producing synthetic fertilizers. Microbial fuel cells offer potential for direct biological conversion of wastewater's organic materials into electricity, although significant improvements are needed for this process to be competitive with anaerobic biological conversion of wastewater organics into biogas, a renewable fuel used in electricity generation. Newer membrane processes coupled with complete anaerobic treatment of wastewater offer the potential for wastewater treatment to become a net generator of energy, rather than the large energy consumer that it is today.     

Leveling the playing field: The use of Twitter by politicians during the 2014 Indian general election campaign

In this study, it is theorized that the communicative affordances offered by social media platforms will enable politically under-resourced candidates to contest the marginalization they face in traditional media. Multivariate analyses were conducted of the tweets of 205 political candidates of the 2014 Indian general election. Findings reveal that fringe party candidates received the least media attention and tended to use Twitter more frequently than major party candidates, especially for interaction and mobilization. Minor party candidates also received less media attention, albeit their Twitter usage patterns were not significantly different than major party candidates. The results illustrate that social media platforms can help overcome resource inequality in politics. The larger implications of this study are discussed.     

Efficient Perovskite Light‐Emitting Diodes Using Polycrystalline Core–Shell‐Mimicked Nanograins

Making small nanograins in polycrystalline organic–inorganic halide perovskite (OIHP) films is critical to improving the luminescent efficiency in perovskite light‐emitting diodes (PeLEDs). 3D polycrystalline OIHPs have fundamental limitations related to exciton binding energy and exciton diffusion length. At the same time, passivating the defects at the grain boundaries is also critical when the grain size becomes smaller. Molecular additives can be incorporated to shield the nanograins to suppress defects at grain boundaries; however, unevenly distributed molecular additives can cause imbalanced charge distribution and inefficient local defect passivation in polycrystalline OIHP films. Here, a kinetically controlled polycrystalline organic‐shielded nanograin (OSN) film with a uniformly distributed organic semiconducting additive (2,2′,2′′‐(1,3,5‐benzinetriyl)‐tris(1‐phenyl‐1‐H‐benzimidazole), TPBI) is developed mimicking core–shell nanoparticles. The OSN film causes improved photophysical and electroluminescent properties with improved light out‐coupling by possessing a low refractive index. Finally, highly improved electroluminescent efficiencies of 21.81% ph el^?1 and 87.35 cd A^?1 are achieved with a half‐sphere lens and four‐time increased half‐lifetime in polycrystalline PeLEDs. This strategy to make homogeneous, defect‐healed polycrystalline core–shell‐mimicked nanograin film with better optical out‐coupling will provide a simple and efficient way to make highly efficient perovskite polycrystal films and their optoelectronics devices.     

Selective Stress Relaxation on Chemically Strengthened Glass Sheets for Conventional Wheel Cutting

We introduce, for the first time to the best of our knowledge, the use of variable frequency microwave (VFM)‐assisted second ion exchange to selectively modify the compressive stress CS in chemically strengthened glass sheets, which allows for separation of these glass sheets into smaller pieces using a conventional cutting tool. The CS in paste‐coated zones, in the regions where it is desired for separation of the glass sheets, was successfully manipulated via VFM‐assisted second ion exchange, substituting the larger alkali ions in glass by smaller ions of the paste. Its effect on chemically strengthened glass was characterized using a strain viewer, an optical microscope, and an electron probe microanalyzer. We also report on the scribability and breakability across the stress relaxation zones. The results reveal a CS loss of only 3%, from 677 to 656 MPa, in the paste‐uncoated zones, and complete CS relaxation, down to 0 MPa, in the paste‐coated regions. The areas of relaxed CS enable the separation of the strengthened glass sheets using conventional wheel cutting.     

Quantitative evaluation of resveratrol enrichment induced by UV stimulus in harvested grapes

A mathematical model was proposed to quantitatively describe resveratrol induction in harvested grapes. In the model, k₁ and k₂ were defined, which were the reaction rate constants for induction during direct UV irradiation and for the time-delayed induction after removing UV irradiation, respectively. During storage after UV irradiation, k₂ decreased with time, whereas k₁ remained constant. The portion induced by the direct irradiation effect was much more than that induced by the time-delayed effect. When UV energy of 610.2 mJ/cm² was applied to ‘Gerbong’ grapes with an initial resveratrol content of 1.15 μg/g, their contents were 8.99 and 9.20 μg/g at day 1 and 6 during storage at 0°C, respectively. In the same situation, resveratrol content of 8.99 μg/g improved to 10.56 μg/g during storage at 20°C. This approach which enriched a health-functional compound through the modulation of metabolism after harvest might be a valueadding method for fresh food industry.