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Measurements of vibration and combustion chamber dynamic pressures have been taken on a number of 150 MW industrial gas turbines operating on pre-mixed natural gas, both during long periods of base-load operation and during short duration load-swings. The data has been analyzed in terms of the frequency and bandwidth of the principle peak in the vibration and pressure spectra as a function of load and other operating parameters. It is observed that bandwidth, which is a measure of the damping of the resonant mode of the combustion chamber's acoustic resonance, decreases towards zero as the machines approach their combustion stability limits. A theoretical model of the thermoacoustic behavior of the combustion system has been developed to see to what extent the observed behavior on the operational machines can be explained in terms of an acoustic model of the ductwork and a flame characterized simply by a time-delay. This time delay is obtained from the frequency response function of the flame in response to unsteady perturbations in inlet velocity and is calculated using computational fluid dynamics. The model has also been used to illustrate the importance of fuel supply system design in controlling combustion stability. It is shown that stability can be a strong function of the acoustic impedance of the fuel supply and that this can lead to enhanced or reduced stability depending on the flame characteristics. [S0742-4795(00)01403-4]

The article provides information on remedies related to merger cases. Competition authorities can deal with anti-competitive mergers in three basic ways: prohibition, structural and behavioral remedies. Several principles guiding competition authorities when making remedies as well as the classification of structural and behavioral remedies are discussed. It is important that a merger remedy must be both effective and administrable. Competition authorities must also exert more effort for timely implementation at minimal cost in terms of institutional resources. In designing remedies, international cooperation and coordination are crucially important in mergers affecting markets that are international in geographical scope.

As with other policies offering lower prices to at least some buyers, loyalty and fidelity discounts are generally pro-competitive and beneficial to consumers even though they may harm certain competitors. Potential problems exist, however, when such discounts are employed in ways that reduce price transparency, exclude or restrict a significant number of actual or potential competitors, or raise the probability of anticompetitive co-ordination. The sometimes complex pro- and anti-competitive effects of loyalty and fidelity discounts are explored in the executive summary, background paper and summary of discussion pertaining to a June 2002 OECD Competition Committee roundtable discussion of the topic. While these documents reveal some interesting policy differences among various members of the Competition Committee, they also point to general agreement that loyalty and fidelity discounts are more likely to raise competition concerns when practised by firms enjoying substantial market power. [ABSTRACT FROM AUTHOR]

It is worth noting that 82% of the cross industry variation in PFRD has been explained without using any explanatory variable measuring the cost advantages of an American versus a 'rest of the world' R & D location. While such a variable certainly belongs in the regressions run, it is and will remain prohibitively difficult to obtain unless the OECD or some other international body publishes suitable comparative data[38]. Significant multicollinearity between this omitted independent variable and the eight others used in the regressions is, with the possible exception of LWRDI, a very remote possibility.
This study develops and empirically tests a 'scenario' describing the evolution of a typical American multinational manufacturing corporation's (AMMC's) foreign research and development (R&D) activity. It finds that international differences in R & D factor costs probably have very little effect on R & D location decisions. The critical variables appear instead to be less traditional things like the time elapsed since the AMMC first engaged in foreign production. That such variables were discovered and emphasized in the study is a result of the 'satisficing' approach adopted in its 'scenario'. In vindicating that approach, the paper's findings also show the need for economic theorizing to take explicit account of the fact that information costs something to obtain and to use. [ABSTRACT FROM AUTHOR]

Abstract. In an article published in this Journal, J.D. Howe and D.S. McFetridge employed an unidentified iterative technique to choose an acceptable deflator for eliminating heteroscedasticity from some regressions investigating across firm differences in R&D spending. This note uses a different R&D data base to show that there are many different deflators capable of passing a Goldfeld-Quandt style lest for heteroscedasticity, and that regression results could depend critically on which of them is chosen. This raises real doubts about the validity of both the iterative technique as a means of identifying acceptable deflators, and of Howe and McFetridge's own empirical results. [ABSTRACT FROM AUTHOR]