Experimental Investigations of Exciting Forces Caused by Flow in Labyrinth Seals

The interaction of the flow through the labyrinth seals with the shaft of the rotor can have an effect on the stability of turbomachines. Thus, the excited forces, so-called cross forces or nonconservative forces, arise, which act perpendicular to the rotor eccentricity. This effect is caused by an unsymmetrical pressure distribution within the labyrinth cavities. Experimental studies were carried out for different types of labyrinth geometries: two staggered labyrinths with teeth on the stator and grooved rotor as well as a full and a convergent stepped labyrinth. These labyrinths can be found on the tip shrouding of bladings in steam or gas turbines. The following parameters were varied in the test facility: geometry of the labyrinth seals (number of cavities, inlet region), shaft rotation, pressure difference on the seal, entry swirl and eccentricity of the rotor. The results are presented for stiffness coefficients of the labyrinth seals, leakage flow and circumferential flow in each cavity which was measured with special probes. Generally, the inlet swirl has the greatest influence on the coefficients of the seals. The experimental results were compared with theoretical results and were in good agreement

EU Company Taxation in Case of a Common Tax Base: A Computer-based Calculation and Comparison Using the Enhanced Model of the European Tax Analyzer

Within the EU the relation between financial and tax accounting will be significantly influenced by the regulation adopted in June 2002 that obliges all listed companies to prepare their consolidated accounts according to International Accounting Standards / International Financial Reporting Standards (IAS/IFRS). Since dependency of financial and tax accounting according to different degrees prevails in all EU member states a linkage between IAS/IFRS and tax accounting seems to be possible. Compared to national GAAP the advantage of IAS/IFRS as a starting point for tax accounting derives from the advantages of the creation of a common tax base in the EU. However, the adoption of IAS/IFRS has to be restricted to those standards that are convenient for tax purposes. In particular, this means that tax accounting still has to follow the realisation principle as a general principle; the IAS/IFRS ?fair value-accounting? therefore cannot be adopted for tax purposes. In this paper we present estimates for the consequences of IAS/IFRS-based tax accounting on the comparative effective tax burdens of companies in 13 countries (Austria, Belgium, the Czech Republic, France, Germany, Hungary, Ireland, Latvia, the Netherlands, Poland, Slovakia, the United Kingdom, and the USA). Therefore, certain provisions of IAS/IFRS were considered as a starting point for the tax base. The effective tax burdens are calculated on the basis of the European Tax Analyzer model which was enhanced for the purposes of this study. A further question arises as to what extent an exclusive harmonisation of the tax base will effectively reduce the current EU-wide differences of effective company tax burdens. It turns out that a common tax base cannot alleviate the current EU-wide differences of effective company tax burdens. A major finding of our study reveals that the effective tax burdens in all countries considered here (except Ireland) tend to increase slightly since the tax bases tend to become broader. This offers the possibility to member states to reduce the nominal tax rate leaving the overall effective tax burden unchanged. A tax policy of tax cut cum base broadening would not only tend to increase the attractiveness of the member states as a location for companies. At the same time, this would reduce dispersions of effective tax burdens across industries. Therefore, such a tax policy is in line of the long term Community goals to become more competitive in international terms. --International Company Taxation,Effective Tax Burden,Tax Accounting,International Accounting Standards

Equilibrium and non-equilibrium effects in relativistic heavy ion collisions

The hypothesis of local equilibrium (LE) in relativistic heavy ion collisions at energies from AGS to RHIC is checked in the microscopic transport model. We find that kinetic, thermal, and chemical equilibration of the expanding hadronic matter is nearly reached in central collisions at AGS energy for t >_ fm/c in a central cell. At these times the equation of state may be approximated by a simple dependence P ~= (0.12-0.15) epsilon. Increasing deviations of the yields and the energy spectra of hadrons from statistical model values are observed for increasing bombarding energies. The origin of these deviations is traced to the irreversible multiparticle decays of strings and many-body (N >_ 3) decays of resonances. The violations of LE indicate that the matter in the cell reaches a steady state instead of idealized equilibrium. The entropy density in the cell is only about 6% smaller than that of the equilibrium state

Stellungnahme zum Steuersenkungsgesetz

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The near-stability of the Lax-Wendroff method

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46325/1/211_2005_Article_BF01397974.pd