2,581 research outputs found

    Efficiency enhancement of black dye-sensitized solar cell by newly synthesized D-π\pi-A coadsorbents: A theoretical study

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    In this work, using the DFT and TDDFT, we have theoretically studied the electronic and optical properties of the two recently synthesized coadsorbents Y1 and Y2, which were aimed to enhance the efficiency of the black dye-sensitized solar cells. To determine the solvatochromic shifts, both the implicit and mixed implicit-explicit models have been used. The connection between the solvatochromic shifts and the changes of dipole moments in the excitation process is discussed. The difference in excitation charge transfer is utilized to explain the experimentally observed difference in JscJ_{sc} for Y1 and Y2. Investigating the interactions of I2_2 molecules in the electrolyte solution with the coadsorbents showed that with Y1 the recombination loss was weakened through decreasing the I2_2 concentration near the TiO2_2 surface, whereas with Y2 it was increased. As a result, the higher values of both JscJ_{sc} and VocV_{oc} with Y1 coadsorbent explains its experimentally observed higher efficiency. The present study sheds light on how to design and engineer newer coadsorbents or organic dyes for higher efficiencies.Comment: 10 pages, Double-column, 11 png figures, LaTeX forma

    Effect of Zataria multiflora Boiss Essential Oil and Grape Seed Extract on the Shelf Life of Raw Buffalo Patty and Fate of Inoculated Listeria monocytogenes

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    The present study was conducted to investigate the effect of Zataria multiflora Boiss essential oil (ZEO) and grape seed extract (GSE) on microbial and chemical changes in raw buffalo patty at a temperature of 8C. First, chemical composition and minimum inhibitory concentration of oil against Listeria monocytogenes were identified. Then, ZEO and GSE were added in raw buffalo patties and analyzed for spoilage microorganism count, lipid oxidation, pH, sensory attributes and inoculated L.monocytogenes survival at 8C for 9 days. Results revealed that samples containing 0.1 ZEO+0.2 GSE showed significant decrease in the growth of all tested microbial groups as well as the most decrease in the level of lipid oxidation at the end of storage period. Control and samples with 0.1 ZEO were the most preferred samples by sensory panelist, indicating that ZEO and GSE can be practically applied in food systems especially in meat in order to extend the shelf life. Practical Applications: Buffalo meat is highly prone to microbial and chemical spoilage as they are rich in essential nutrients and putrefying in nature. The adverse effects of various chemical preservatives caused to attract the consumer's attention to natural alternatives. Therefore, in order to increase the shelf life and quality characteristics of meat, new processing technologies and new ingredient systems that are associated with natural and organic foods are applied. These results demonstrate the potential combined use of grape seed extract and Zataria multiflora Boiss essential oil to the meat industry in the development of novel healthy meat products with improved shelf life and superior product quality. © 2015 Wiley Periodicals, Inc

    SUSY dark matter and lepton flavor violation

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    We study lepton flavor-violating (LFV) processes within a supersymmetric type-I seesaw framework with flavor-blind universal boundary conditions, properly accounting for the effect of the neutrino sector on the dark matter relic abundance. We consider several possibilities for the neutrino Yukawa coupling matrix and show that in regions of SUSY parameter space that yield the correct neutralino relic density, LFV rates can differ from naive estimates by up to two orders of magnitude. Contrary to common belief, we find that current LFV limits do not exclude neutrino Yukawa couplings larger than top Yukawa couplings. We introduce the ISAJET-M program that was used for the computations.Comment: 37 pages, 9 figures, 6 tables. Version to appear in PR

    On the Growth of Al_2 O_3 Scales

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    Understanding the growth of Al2O3 scales requires knowledge of the details of the chemical reactions at the scale–gas and scale–metal interfaces, which in turn requires specifying how the creation/annihilation of O and Al vacancies occurs at these interfaces. The availability of the necessary electrons and holes to allow for such creation/annihilation is a crucial aspect of the scaling reaction. The electronic band structure of polycrystalline Al2O3 thus plays a decisive role in scale formation and is considered in detail, including the implications of a density functional theory (DFT) calculation of the band structure of a Σ7 View the MathML source bicrystal boundary, for which the atomic structure of the boundary was known from an independent DFT energy-minimization calculation and comparisons with an atomic-resolution transmission electron micrograph of the same boundary. DFT calculations of the formation energy of O and Al vacancies in bulk Al2O3 in various charge states as a function of the Fermi energy suggested that electronic conduction in Al2O3 scales most likely involves excitation of both electrons and holes, which are localized on singly charged O vacancies, View the MathML source and doubly charged Al vacancies, View the MathML source, respectively. We also consider the variation of the Fermi level across the scale and bending (“tilting”) of the conduction band minimum and valence band maximum due to the electric field developed during the scaling reaction. The band structure calculations suggest a new mechanism for the “reactive element” effect—a consequence of segregation of Y, Hf, etc., to grain boundaries in Al2O3 scales, which results in improved oxidation resistance—namely, that the effect is due to the modification of the near-band edge grain-boundary defect states rather than any blocking of diffusion pathways, as previously postulated. Secondly, Al2O3 scale formation is dominated by grain boundary as opposed to lattice diffusion, and there is unambiguous evidence for both O and Al countercurrent transport in Al2O3 scale-forming alloys. We postulate that such transport is mediated by migration of grain boundary disconnections containing charged jogs, rather than by jumping of isolated point defects in random high-angle grain boundaries

    A Case of Urogenital Human Schistosomiasis from a Non-endemic Area

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    © 2015 Calvo-Cano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

    Human-Machine Interface for Tele-Robotic Operation: Mapping of Tongue Movements Based on Aural Flow Monitoring

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    2004 IEEE International Conference on Intelligent Robots and Systems (IROS), October, 2004 (Awarded “Best Paper in Conference”

    Nutrientes de cultivares de Cynodon, em duas épocas do ano, no Estado do Piauí.

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    Avaliaram-se os teores de proteína bruta, cálcio e fósforo em oito cultivares de cynodon: C. dactylon (L.) Pers. var. Aridus cv. Callie, C. dactylon (L.) Pers. cv. Coastcross, C. nlemfuensis Vanderyst cv. Estrela africana..
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