The suppression of the regenerative chatter phenomenon in turning process via the variation of the frequency and amplitude of the spindle motor excitation is carried out in this research. A programmable inverter is employed for variable periodic excitation of the spindle motor. A set of turning experiments is designed and performed on a number of conical work pieces both in constant spindle spe...

Dendritic flux penetration is a well known phenomenon in high temperature superconductors. We investigated the conditions under which this instability can be observed in different materials. We found three qualitatively different behaviors: dendrite development above a “critical field” and up to a certain temperature, above a “critical field” with no measurable temperature dependence, or no den...

We present a numerical study of critical phenomena (including the Lue-Weinberg phenomenon) arising for gravitating monopoles in a global monopole spacetime. The equations of this model have been recently studied by Spinelly et al. in a domain of parameter space away from the critical points. PACS numbers: 04.20.Jb, 04.40.Nr, 14.80.Hv Typeset using REVTEX [email protected] Betti.Hartmann@du...

The suppression of the regenerative chatter phenomenon in turning process via the variation of the frequency and amplitude of the spindle motor excitation is carried out in this research. A programmable inverter is employed for variable periodic excitation of the spindle motor. A set of turning experiments is designed and performed on a number of conical work pieces both in constant spindle spe...

We report new VLT/NACO imaging observations of the young, nearby brown dwarf 2MASSW J1207334−393254 and its suggested planetary mass companion (2M1207 b). Three epochs of VLT/NACO measurements obtained over nearly one year show that the planetary mass companion candidate shares the same proper motion and, with a high confidence level, is not a stationary background object. This result confirms ...

The mathematical description of laboratory fusion plasmas produced in Tokamaks is still challenging. Complete models for electrons and ions, as Vlasov-Maxwell systems, are computationally too expensive because they take into account all details and scales of magneto-hydrodynamics. In particular, for most of the relevant studies, the mass electron is negligible and the velocity of material waves...

This review discusses instabilities of the Fermi-liquid state of conduction electrons in metals with particular emphasis on magnetic quantum critical points. Both the existing theoretical concepts and experimental data on selected materials are presented; with the aim of assessing the validity of presently available theory. After briefly recalling the fundamentals of Fermi-liquid theory, the lo...