12 research outputs found

    Fruits and vegetables preference among university students towards developing healthy food innovation products

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    No AbstractKeywords: fruits; vegetables; preference; university student

    Grids of stellar models with rotation VII : models from 0.8 to 300 M⊙ at supersolar metallicity (Z = 0.020)

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    We present a grid of stellar models at supersolar metallicity (Z = 0.020) extending the previous grids of Geneva models at solar and sub-solar metallicities. A metallicity of Z = 0.020 was chosen to match that of the inner Galactic disc. A modest increase of 43 per cent (= 0.02/0.014) in metallicity compared to solar models means that the models evolve similarly to solar models but with slightly larger mass-loss. Mass-loss limits the final total masses of the supersolar models to 35 M⊙ even for stars with initial masses much larger than 100 M⊙. Mass-loss is strong enough in stars above 20 M⊙ for rotating stars (25 M⊙ for non-rotating stars) to remove the entire hydrogen-rich envelope. Our models thus predict SNII below 20 M⊙ for rotating stars (25 M⊙ for non-rotating stars) and SNIb (possibly SNIc) above that. We computed both isochrones and synthetic clusters to compare our supersolar models to the Westerlund 1 (Wd1) massive young cluster. A synthetic cluster combining rotating and non-rotating models with an age spread between log10(age/yr) = 6.7 and 7.0 is able to reproduce qualitatively the observed populations of WR, RSG, and YSG stars in Wd1, in particular their simultaneous presence at log10(L/L⊙) = 5–5.5. The quantitative agreement is imperfect and we discuss the likely causes: synthetic cluster parameters, binary interactions, mass-loss and their related uncertainties. In particular, mass-loss in the cool part of the HRD plays a key role

    Recent Advances in Modeling Stellar Interiors

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    Advances in stellar interior modeling are being driven by new data from large-scale surveys and high-precision photometric and spectroscopic observations. Here we focus on single stars in normal evolutionary phases; we will not discuss the many advances in modeling star formation, interacting binaries, supernovae, or neutron stars. We review briefly: 1) updates to input physics of stellar models; 2) progress in two and three-dimensional evolution and hydrodynamic models; 3) insights from oscillation data used to infer stellar interior structure and validate model predictions (asteroseismology). We close by highlighting a few outstanding problems, e.g., the driving mechanisms for hybrid gamma Dor/delta Sct star pulsations, the cause of giant eruptions seen in luminous blue variables such as eta Car and P Cyg, and the solar abundance problem.Comment: Proceedings for invited talk at conference High Energy Density Laboratory Astrophysics 2010, Caltech, March 2010, submitted for special issue of Astrophysics and Space Science; 7 pages; 5 figure

    Band structure and density of states in the normal state of FeSe, Fe2Se2, Fe2Se1 and Fe2SeTe superconductors

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    We have calculated the band structure of FeSe. FeSe from which 2 atoms of Se out of 4 per unit cell have been removed and a system in which 2 Te atoms have been substituted for 2 Se atoms in a unit cell in the normal state. In all of the cases the Fermi energies cross multiple bands and there is always at least one conduction band minimum whose energy is lower than the valence band maximum. Hence, on the basis of the calculated band structures, these systems have no semiconducting band gap and should behave as metals. Similarly, there is non-vanishing density of states at the Fermi level. Large effects are found in the density of states. The normal state gap reduces in the composition which becomes superconducting. (C) 2010 Elsevier B.V. All rights reserved

    DFT calculations of vibrational frequencies of carbon-nitrogen clusters: Raman spectra of carbon nitrides

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    We have performed the calculation of structures of clusters containing carbon and nitrogen atoms. We determine the bond lengths in each case. We also calculate the vibrational frequencies of all of the clusters. We compare the calculated values of the vibrational frequencies with those measured by the Raman spectra of amorphous carbon nitrides. Some of the calculated frequencies are in agreement with those measured. We identity that linear structures and hence ``back bones'' are present in the glassy state

    Radiometric analysis of construction materials using Hpge Gamma-Ray spectrometry

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    Concentrations of primordial radionuclides in common construction materials collected from the south-west coastal region of India were determined using a high-purity germanium gamma-ray spectrometer. Average specific activities (Bq kg(-1)) for U-238(Ra-226) in cement, brick, soil and stone samples were obtained as 54 +/- 13, 21 +/- 4, 50 +/- 12 and 46 +/- 8, respectively. Respective values of Th-232 were obtained as 65 +/- 10, 21 +/- 3, 58 +/- 10 and 57 +/- 12. Concentrations of K-40 radionuclide in cement, brick, soil and stone samples were found to be 440 +/- 91, 290 +/- 20, 380 +/- 61 and 432 +/- 64, respectively. To evaluate the radiological hazards, radium equivalent activity, various hazard indices, absorbed dose rate and annual effective dose have been calculated, and compared with the literature values. Obtained data could be used as reference information to assess any radiological contamination due to construction materials in future
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