93,283 research outputs found

    State Control of Interstate Air Pollution

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    Global warming is an unequivocal fact proved by the persistent rise of the average temperature of the earth. IPCC reported that scientists were more than 90 % certain that most of the global warming was caused by increasing concentrations of greenhouse gases (GHG) produced by human activities. One alternative to combat the GHG is to explore technologies for utilizing CO2 already generated by current energy systems and develop methods to convert CO2 into useful combustible gases. Two-step conversion of CO2 with catalysts is one of the most promising methods. Ceria (CeO2) is chosen as the main catalyst for this conversion in the thesis. It releases O2 when it is reduced in a heating process, and then absorbs O2 from CO2 to produce CO when it is re-oxidized in a cooling process. To make the conversion economic, solar power is employed to drive the conversion system. In this thesis, a flexible system with fluidized bed reactors (FBRs) is introduced. The thermogravimetric analysis (TGA) was carried out to examine the performance of ceria during its reduction and oxidation. Subsequently, the exergy analysis was used to evaluate the system’s capability on exporting work. The theoretical fuel to chemical efficiency varied from 4.85 % to 43.2 % for CO2 conversions. To investigate the operation mechanism of the system, a mathematical model was built up for the dynamic simulation of the system. Variables such as temperatures and efficiencies were calculated and recorded for different cases. The optimum working condition was found out to be at 1300 ⁰C for the commercial type of ceria. Finally, an experimental system was set up. The hydrodynamics and heat transfer in the fluidized bed reactor were studied. A CFD model was built up and validated with the experimental trials around 120 ⁰C. The model was then used as a reliable tool for the optimization of the reactor. The entire work in the thesis follows the procedure of developing an engineering system. It forms a solid basis for further improvements of the system to recycle CO2.QC 20141006</p

    Luther on revelation: foundation for proclamation and worship

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    Luther\u27s struggles in the monastery were characterized by his preoccupation with a theology of glory (God Hidden; God in glory and majesty; Christ the King; human attempts to reach God; works righteousness). His evangelical breakthrough led him to a theology of the Cross (God revealed in Christ; the humility of Christ in the Child of Bethlehem and Man of Calvary). His liturgical forms, and those of later Lutherans, reflected this. Recently, a theology of glory has returned (majestic attributes of God; triumphalism; \u27celebration theology\u27 and reenactment of saving acts rather than proclamation and hearing). The distinction of law and gospel provides the corrective

    State Control of Interstate Air Pollution

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    X-stream assessments: utilising new technology to assess sports marketing students

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    Rocket injector head

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    A high number of liquid oxygen and gaseous hydrogen orifices per unit area are provided in an injector head designed to give intimate mixing and more thorough combustion. The injector head comprises a main body portion, a cooperating plate member as a flow chamber for one propellant, a cooperating manifold portion for the second propellant, and an annular end plate for enclosing an annular propellant groove formed around the outer edge of the body. All the openings for one propellant are located at the same angle with respect to a radial plane to permit a short combustion chamber

    The radial distributions of a heavy-light meson on a lattice

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    In an earlier work, the charge (vector) and matter (scalar) radial distributions of heavy-light mesons were measured in the quenched approximation on a 16^3 times 24 lattice with a quark-gluon coupling of 5.7, a lattice spacing of 0.17 fm, and a hopping parameter corresponding to a light quark mass about that of the strange quark. Several improvements are now made: 1) The configurations are generated using dynamical fermions with a quark-gluon coupling of 5.2 (a lattice spacing of 0.14 fm); 2) Many more gauge configurations are included (78 compared with the earlier 20); 3) The distributions at many off-axis, in addition to on-axis, points are measured; 4) The data-analysis is much more complete. In particular, distributions involving excited states are extracted. The exponential decay of the charge and matter distributions can be described by mesons of mass 0.9+-0.1 and 1.5+-0.1 GeV respectively - values that are consistent with those of vector and scalar qqbar-states calculated directly with the same lattice parameters.Comment: 3 pages, 4 figures, Lattice2002(heavyquark

    Are flexible contracts bad for workers? Evidence from job satisfaction data

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    If workers can choose between permanent and flexible contracts, compensating wage differentials should arise to equalize on-the-job utility in the two types of contracts. Estimating job satisfaction using the British Household Panel Survey shows that agency and casual contracts are associated with routinely lower satisfaction. This results because the low job satisfaction associated with less job security is not offset by higher compensation or other job characteristics. Job security is sufficiently important that holding constant this one facet of satisfaction eliminates the overall gap in job satisfaction between flexible and permanent contracts

    Fat Cats and Thin Kittens: Are People Who Make Large Campaign Contributions Different?

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    Critics of campaign finance in the United States often direct their fire toward contributors who make large donations. Critics charge that large contributions are unfair, unrepresentative, and undemocratic. Accordingly, they push for "reforms" that would favor small contributions over large, and public money over private donations. Survey data on contributors contradict that stereotype of contributors of large amounts and their effects on American politics. Overall, "fat cats" differ less from contributors of smaller amounts than critics have alleged. The differences that do exist are mostly unsurprising and generally small in magnitude. Survey results show that both policy liberalism and Democratic partisanship are well represented among contributors of large sums.The supporters of McCain-Feingold argue that new restrictions on large contributions will profoundly alter American politics for the better. Their claims have no basis in fact. New laws aimed at restricting large donations in favor of smaller ones will have little effect on practical politics

    Assessing probabilistic forecasts about particular situations

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    How useful are probabilistic forecasts of the outcomes of particular situations? Potentially, they contain more information than unequivocal forecasts and, as they allow a more realistic representation of the relative likelihood of different outcomes, they might be more accurate and therefore more useful to decision makers. To test this proposition, I first compared a Squared-Error Skill Score (SESS) based on the Brier score with an Absolute-Error Skill Score (AESS), and found the latter more closely coincided with decision-makers’ interests. I then analysed data obtained in researching the problem of forecasting the decisions people make in conflict situations. In that research, participants were given lists of decisions that might be made and were asked to make a prediction either by choosing one of the decisions or by allocating percentages or relative frequencies to more than one of them. For this study I transformed the percentage and relative frequencies data into probabilistic forecasts. In most cases the participants chose a single decision. To obtain more data, I used a rule to derive probabilistic forecasts from structured analogies data, and transformed multiple singular forecasts for each combination of forecasting method and conflict into probabilistic forecasts. When compared using the AESS, probabilistic forecasts were not more skilful than unequivocal forecasts.accuracy, error measures, evaluation, forecasting methods, prediction
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