7,085 research outputs found

    The MC@NLO 3.2 Event Generator

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    This is the user's manual of MC@NLO 3.2. This package is a practical implementation, based upon the HERWIG event generator, of the MC@NLO formalism, which allows one to incorporate NLO QCD matrix elements consistently into a parton shower framework. Processes available in this version include the hadroproduction of single vector and Higgs bosons, vector boson pairs, heavy quark pairs, single top, lepton pairs, and Higgs bosons in association with a W or Z. Spin correlations in decays are included for all processes except ttbar, single-t, ZZ, and WZ production. This document is self-contained, but we emphasise the main differences with respect to previous versions.Comment: 23 pages Late

    Evaluation of power generation operations in response to changes in surface water reservoir storage

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    We used a customized, river basin-based model of surface water rights to evaluate the response of power plants to drought via simulated changes in reservoir storage. Our methodology models surface water rights in 11 river basins in Texas using five cases: (1) storage decrease of existing capacity of 10%, (2) storage decrease of 50%, (3) complete elimination of storage, (4) storage increase of 10% (all at existing locations), and (5) construction of new reservoirs (at new locations) with a total increase in baseline reservoir capacity for power plant cooling of 9%. Using the Brazos River basin as a sample, we evaluated power generation operations in terms of reliability, resiliency, and vulnerability. As simulated water storage decreases, reliability generally decreases and resiliency and vulnerability remain relatively constant. All three metrics remain relatively constant with increasing reservoir storage, with the exception of one power plant. As reservoir storage changes at power plants, other water users in the basin are also affected. In general, decreasing water storage is beneficial to other water users in the basin, and increasing storage is detrimental for many other users. Our analysis reveals basin-wide and individual power plant-level impacts of changing reservoir storage, demonstrating a methodology for evaluation of the sustainability and feasibility of constructing new reservoir storage as a water and energy management approach.Mechanical Engineerin

    A Positive-Weight Next-to-Leading-Order Monte Carlo for e+e- Annihilation to Hadrons

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    We apply the positive-weight Monte Carlo method of Nason for simulating QCD processes accurate to Next-To-Leading Order to the case of e+e- annihilation to hadrons. The method entails the generation of the hardest gluon emission first and then subsequently adding a `truncated' shower before the emission. We have interfaced our result to the Herwig++ shower Monte Carlo program and obtained better results than those obtained with Herwig++ at leading order with a matrix element correction.Comment: 21 pages, 11 figures, 2 tables Reason for replacement: minor corrections, typos and 1 changed referenc

    An international information literacy certificate: opportunity or dead-end?

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    This paper presents the case against developing an International Information Literacy Certificate. After defining information literacy (IL) the author identifies that there is diversity amongst those who need to learn about IL, that they have diverse needs and will be in diverse contexts. An individual’s IL needs also change through that person’s lifetime. The author identifies IL as a complex subject and discusses the implications of this complexity for learning, teaching and assessment. The “standards” approach to IL, ennumerating qualities and activities, is criticised. Three examples of a context-sensitive approach to IL education are given (in a university, a workplace and a school). Taking the example of the European Computer Driving Licence, the author argues that IL is like neither driving nor computer competency. It is questioned whether an IL certificate would help to raise the prestige of IFLA and librarians, and problems of consensus and practicality are discussed. The author concludes that the certificate would be a “dead-end”. However, she finishes by confirming that there could still be a role for an IL foundation. She proposes that it starts with an agenda of “IL for the child”, and she confirms the importance of IL in today’s information society

    Alloy dissolution in argon stirred steel

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    Alloying is required for the production of all steel products from small castings to large beams. Addition of large quantities of bulk alloys can result in alloy segregation and inconsistent alloy recovery. The objective of this research was to better understand alloy dissolution in liquid steel especially as it relates to Missouri S&Ts\u27 patented continuous steelmaking process. A 45-kilogram capacity ladle with a single porous plug was used to evaluate the effect of four experimental factors on alloy dissolution: alloy species, alloy size or form, argon flow rate, and furnace tap temperature. Four alloys were tested experimentally including Class I low carbon ferromanganese, nickel and tin (as a surrogate for low melting alloys) and Class II ferroniobium. The alloys ranged in size and form from granular to 30 mm diameter lumps. Experimental results were evaluated using a theoretically based numerical model for the steel shell period, alloy mixing (Class I) and alloy dissolution (Class II). A CFD model of the experimental ladle was used to understand steel motion in the ladle and to provide steel velocity magnitudes for the numerical steel shell model. Experiments and modeling confirmed that smaller sized alloys have shorter steel shell periods and homogenize faster than larger particles. Increasing the argon flow rate shortened mixing times and reduced the delay between alloy addition and the first appearance of alloy in the melt. In addition, for every five degree increase in steel bath temperature the steel shell period was shortened by approximately four percent. Class II ferroniobium alloy dissolution was an order of magnitude slower than Class I alloy mixing --Abstract, page iii
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