515,296 research outputs found
Recent development in organic scintillators
Discussion on recent developments of organic scintillators includes studies of organic compounds that form glass-like masses which scintillate and are stable at room temperature, correlations between molecular structure of organic scintillators and self-quenching, recently developed fast scintillators, and applications of liquid-scintillation counters
Gaugino Determinant in Supersymmetric Yang-Mills Theory
We resolve an ambiguity in the sign of the gaugino determinant in
supersymmetric models. The result, that the gaugino determinant can be taken
positive for all background gauge configurations, is necessary for application
of QCD inequalities and lattice Monte Carlo methods to supersymmetric
Yang-Mills models.Comment: 5 pages, LaTeX. Revised version to appear in Modern Physics Letters
Mechanism of lubrication by tricresylphosphate (TCP)
The coefficient of friction was measured as a function of temperature on a pin-on-disk tribometer. Pins and disks of 440C and 52100 steels were lubricated with tricresylphosphate (TCP), 3.45 percent TCP in squalene, and pure squalene. The M-50 pins and disks were lubricated with 3.45 percent TCP in squalene and pure squalene. Experiments were conducted under limited lubrication conditions in dry ( 100 ppm H2O) air and dry ( pp H2O) nitrogen at 50 rpm (equivalent to a sliding velocity of 13 cm sec) and a constant load of 9.8 N (1 kg). Characteristic temperatures T sub r were identified for TCP on 52100 steel and for squalene on M-50 and 52100 steels, where the friction decreased because of a chemical reaction between the lubricant and the metal surface. The behavior of squalene obscured the influence of 3.45 percent TCP solute on the friction of the system. Wear volume measurements demonstrated that wear was lowest at temperatures just above T sub r. Comparing the behavior of TCP on M-50, 440C, and 52100 steels revealed that the TCP either reacted to give T sub r behavior or produced initial failure in the temperature range 223 + or - 5 C
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An Evaluation of Non-Stochastic Lattice Structures Fabricated Via Electron Beam Melting
Metal foam structures have many applications and can be used as structural supports, heat
exchangers, shock absorbers, and implant materials. Stochastic metal foams having different cell
sizes and densities have been commercially available for a number of years. This paper addresses
a different type of foams which are known as non-stochastic foams, or lattice structures. These
foams have a well defined repeating unit cell structure rather than the random cell structure in
commercially available stochastic foams. The paper reports on preliminary research on the
fabrication of non-stochastic Ti-6Al-4V alloy foams using the Electron Beam Melting process.
Behavior of the structures in compression, bending, and low cycle repeating load tests are
discussed, and recommendations about cell geometry and processing conditions are made.Mechanical Engineerin
No radiative generation of Chern-Simons-like term in Lorentz-violating QED: dealing with IR divergences
The issue intensively claimed in the literature on the generation of a
CPT-odd and Lorentz violating Chern-Simons-like term by radiative corrections
owing to a CPT violating interaction -- the axial coupling of fermions with a
constant vector field b_\m -- is mistaken. The presence of massless gauge
field triggers IR divergences that might show up from the UV subtractions,
therefore, so as to deal with the (actual physical) IR divergences, the
Lowenstein-Zimmermann subtraction scheme, in the framework of BPHZL
renormalization method, has to be adopted. The proof on the non generation of
such a Chern-Simons-like term is done, independent of any kind of
regularization scheme, at all orders in perturbation theory.Comment: In honor of Prof. Manfred Schweda (1939-2017). Work presented at the
XXXVIII National Meeting on Particle Physics and Fields, September 18-22,
2017 - Passa Quatro - Minas Gerais - Brazil. Reference [46] correcte
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