720 research outputs found
Antibaryons in massive heavy ion reactions: Importance of potentials
In the framework of RQMD we investigate antiproton observables in massive
heavy ion collisions at AGS energies and compare to preliminary results of the
E878 collaboration. We focus here on the considerable influence of the *real*
part of an antinucleon--nucleus optical potential on the antiproton momentum
spectra
Covariance of Antiproton Yield and Source Size in Nuclear Collisions
We confront for the first time the widely-held belief that combined
event-by-event information from quark gluon plasma signals can reduce the
ambiguity of the individual signals. We illustrate specifically how the
measured antiproton yield combined with the information from pion-pion HBT
correlations can be used to identify novel event classes.Comment: 8 pages, 5 figures, improved title, references and readability;
results unchange
Impact of maximum back-EMF limits on the performance characteristics of interior permanent magnet synchronous machines
Interior permanent magnet (IPM) synchronous machines are vulnerable to uncontrolled generator (UCG) faults at high speed that can damage the inverter. One approach to reducing this risk is to impose limits on the maximum machine back-EMF voltage at top speed. This paper presents the results of a comparative design study that clarifies the nature and extent of the penalties imposed on the IPM machine metrics and performance characteristics as a result of imposing progressively tighter values of back-EMF voltage limits. As an alternative to limiting back-EMF and penalizing machine designs, this paper also investigates the effectiveness of the system-side protection approach to the same UCG fault problem.Seok-hee Han, Thomas M. Jahns, Metin Aydin, Mustafa K. Guven, Wen L. Soon
Breast abscess due to Actinomyces europaeus
Actinomyces europaeus was first described in 1997 as a new species causing predominantly skin and soft-tissue infections. Mastitis due to A. europaeus is an unusual condition. This article reports a case of primary breast abscess caused by A. europaeus in a postmenopausal woma
Enhanced antiproton production in Pb(160 AGeV)+Pb reactions: evidence for quark gluon matter?
The centrality dependence of the antiproton per participant ratio is studied
in Pb(160 AGeV)+Pb reactions. Antiproton production in collisions of heavy
nuclei at the CERN/SPS seems considerably enhanced as compared to conventional
hadronic physics, given by the antiproton production rates in and
antiproton annihilation in reactions. This enhancement is consistent
with the observation of strong in-medium effects in other hadronic observables
and may be an indication of partial restoration of chiral symmetry
Atp bioluminescence for rapid and selective detection of bacteria and yeasts in wine
Microbial contamination may represent a loss of money for wine producers as several defects can arise due to a microorganismâs growth during storage. The aim of this study was to implement a bioluminescence assay protocol to rapidly and simultaneously detect bacteria and yeasts in wines. Different wines samples were deliberately contaminated with bacteria and yeasts at different concentrations and filtered through two serial filters with decreasing mesh to separate bacteria and yeasts. These were resuscitated over 24 h on selective liquid media and analyzed by bioluminescence assay. ATP measurements discriminated the presence of yeasts and bacteria in artificially contaminated wine samples down to 50 CFU/L of yeasts and 1000 CFU/L of bacteria. The developed protocol allowed to detect, rapidly (24 h) and simultaneously, bacteria and yeasts in different types of wines. This would be of great interest for industries, for which an early detection and discrimination of microbial contaminants would help in the decisionâmaking proces
Design and experimental verification of a 50 kW interior permanent magnet synchronous machine
This paper presents the design details for an IPM machine designed to deliver 50 kW constant power over a 5:1 speed range extending from 850 rpm to 4250 rpm, with a gradual reduction in the required output power up to 8000 rpm (25 kW). Electromagnetic, thermal, and structural considerations have been included in the design optimization process. The resulting machine is designed with two magnet layers per pole and a distributed stator winding. Special features of the machine include its deep stator slots and four-layer winding, made necessary by the desire to minimize the machine's moment of inertia. Test results available to date demonstrate that the machine is capable of delivering the required output torque and power, and the agreement between the predicted and measured machine parameters is generally quite good. Calculated iron losses for high-speed flux-weakening operation are presented in the final section of the paper, illustrating the challenges associated with minimizing the impact of high-frequency harmonic flux density components.Jahns, T.M.; Seok-Hee Han; El-Refaie, A.M.; Jei-Hoon Baek; Aydin, M.; Guven, M.K.; Soong, W.L
Hollow waveguides as polarization converting elements: a theoretical study
Subwavelength apertures in a metallic film act as hollow waveguides. By using a non-quadratic cross-section, an anisotropic transmission behaviour results for the two polarization states. Thus, an array of metallic subwavelength apertures may be used as polarization converter, e.g., as a half-wave plate. By varying orientation and shape of the cross-sections locally, one can design polarization shifting elements for complex wave fields. Here, we present a theoretical consideration on the physical properties and compare with dielectric form birefringence
Self-imaging effect in multimode waveguides with longitudinal periodicity
This paper deals with the self--imaging effect in multimode waveguides. Analogies and differences to the free--space case are shown. The fields in multimode waveguides are studied. Particularly, the behavior of the fields is examined, when aperiodic perturbation is introduced
Are we close to the QGP? - Hadrochemical vs. microscopic analysis of particle production in ultrarelativistic heavy ion collisions
Ratios of hadronic abundances are analyzed for pp and nucleus-nucleus
collisions at sqrt(s)=20 GeV using the microscopic transport model UrQMD.
Secondary interactions significantly change the primordial hadronic cocktail of
the system. A comparison to data shows a strong dependence on rapidity. Without
assuming thermal and chemical equilibrium, predicted hadron yields and ratios
agree with many of the data, the few observed discrepancies are discussed.Comment: 12 pages, 4 figure
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