11,900 research outputs found

    BB and BcB_c mesons with NRQCD and Clover actions

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    We present preliminary results from our study of the heavy-light spectrum and decay constants. For the heavy quark, we use NRQCD at various masses around and above the bb quark mass. For the first time, the heavy quark action and the heavy-light current consistently include corrections at second order in the non-relativistic expansion, as well as the leading finite aa corrections. The light quarks are simulated using a tadpole-improved Clover action at various masses in the strange and cc quark region.Comment: 6 Pages LaTex. Axis files of figures included. Joint writeup of two talks presented at LATTICE96(heavy quarks

    f_B and the Heavy-light Spectrum from NRQCD

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    The present status of lattice calculations of the B spectrum and f_B, using NRQCD for the b quark, is discussed.Comment: 6 pages, LaTeX, 3 postscript figures, uses espcrc2, curves (included), and epsf. To appear in the proceedings of Lattice `97, Edinburgh, Scotland, July 22--26, 199

    Chiral Perturbation Theory and Finite Size Effects on the Nucleon Mass in unquenched QCD

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    We calculate finite size effects on nucleon masses in chiral perturbation theory. We confront the theoretical predictions with N_f=2 lattice results and discuss chiral extrapolation formulae.Comment: talk at Lattice 03 (spectrum), 3 pages latex, 3 figures. Assignment of 2 data points to incorrect data sets in plot 1 and of 1 data point in plot 2 corrected. 1 fm lattice result updated. Conclusions unchange

    The Nambu-Jona-Lasinio model with staggered fermions

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    We investigate the neighbourhood of the chiral phase transition in a lattice Nambu--Jona-Lasinio model, using both Monte Carlo methods and lattice Schwinger-Dyson equations.Comment: Talks at LAT93, Dallas, U.S.A. Postscript file, 6 pages, figures include

    Carbon neutrality concept and progress

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    Sufficient scientific evidence now shows that Earth’s temperature is warmer than before. The temperature of the planet (global warming) is becoming s source of climate change that is estimated to have negative consequences for all living beings (Sovacool and Griffiths, 2020). Climate change, if it keeps moving in the direction in which it is heading now, will have severe consequences for anything and everything that exists on this planet. This is not a man-made story; rather, the argument is established upon the data collected by international organizations such as United Nations’ Intergovernmental Panel on Climate Change, Environmental Protection Agency, and NASA, among others. Data on global warming have been gathered across multiple time periods and analyzed for a very long time to arrive at the conclusion of severe and unpleasant consequences for everyone and everything on the planet. Excessive carbon dioxide emis- sions is the main contributing factor of global warming. However, it is not only carbon dioxide that causes global warming—many other gases are harmful to the climate, such as carbon dioxide, methane, and nitrous oxide, as well as hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. This is not an exhaustive list, but for now, think of greenhouse gases as a catch-all term for the harmful substances we are pumping into the atmo- sphere. Since carbon dioxide has the most significant share among harmful gases, academic and nonacademic researchers study carbon dioxide more than other gases

    Electric Power Generation from Solar Photovoltaic Technology: Is It Marketable in Pakistan?

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    Solar photovoltaic systems are prohibitively expensive in terms of installation costs. Power from them is also available intermittently—only when energy from the sun is available. On the other hand, PV systems are free of the ever-rising costs of input fuel. They also incur much less operation and maintenance costs and are supposed to have a longer lifetime than, for example, a fossil fuel power plant. Thus using solar-PV power looks uneconomical in the short term, but may be profitable in the long term. It is, therefore, interesting to identify the factors that can make investment in solar PV power generation acceptable. This paper carries out a financial analysis of installing a 10 MW solar photovoltaic power generation plant for sale of electricity to a grid. It compares the levelised cost of this mode of energy generation as compared to a fossil fuel plant. It also calculates the cost of electricity generation and tariff for power from this plant. It then identifies the factors that can make the investment in a grid-scale solar PV plant more favourable than investment in other conventional and non-renewable sources.Solar Energy
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