Correlation between UV and IR cutoffs in quantum field theory and large extra dimensions

A recently conjectured relashionship between UV and IR cutoffs in an effective field theory without quantum gravity is generalized in the presence of large extra dimensions. Estimates for the corrections to the usual calculation of observables within quantum field theory are used to put very stringent limits, in some cases, on the characteristic scale of the additional compactified dimensions. Implications for the cosmological constant problem are also discussed.Comment: 6 pages, Latex fil

Single-W Production and Fermion-Loop Scheme: Numerical Results

The single-W production mechanism is synonymous to the electron-positron annihilation into electron, neutrino and a W boson with the outgoing electron lost in a small cone around the beam direction. It requires a Renormalization Scheme that preserves gauge invariance and fermion masses cannot be neglected in the calculation. A recently proposed generalization of the so-called Fermion-Loop scheme is applied to the evaluation of observables at LEP 2 energies. Single-W processes are dominated by a regime of low momentum transfer of the outgoing electron and any high-energy Renormalization Scheme fails to give the correct description of the scale. The Fermion-Loop scheme automatically converts all couplings of the theory into couplings that are running at the appropriate scale. Therefore, in addition to represent the only scheme fully justified on a field-theoretical basis, the Fermion-Loop is the best starting point to include radiative corrections into single-W production. Numerical results are presented, showing a decrease in the predictions that can be sizeable. There is no naive and overall rescaling of the e.m. coupling constant, in any pragmatic scheme, that can reproduce the Fermion-Loop results, at the requested accuracy, for all configurations and for all kinematical cuts.Comment: 27 pages(Latex), 7 figure

Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal) is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP). Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt

Correction: Zhou, J.; et al. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing. Lubricants 2015, 3, 3–13

The authors wish to make the following corrections to this paper [1]. In Table 2, the tensile strength (100 °C) of Babbitt is 40 MPa, not 45 MPa[...