11,820 research outputs found
Cold plasma processing of local planetary ores for oxygen and metallurgically important metals
The utilization of a cold plasma in chlorination processing is described. Essential equipment and instruments were received, the experimental apparatus assembled and tested, and preliminary experiments conducted. The results of the latter lend support to the original hypothesis: a cold plasma can both significantly enhance and bias chemical reactions. In two separate experiments, a cold plasma was used to reduce TiCl4 vapor and chlorinate ilmenite. The latter, reacted in an argon-chlorine plasma, yielded oxygen. The former experiment reveals that chlorine can be recovered as HCl vapor from metal chlorides in a hydrogen plasma. Furthermore, the success of the hydrogen experiments has lead to an analysis of the feasibility of direct hydrogen reduction of metal oxides in a cold plasma. That process would produce water vapor and numerous metal by-products
Cold plasma processing of local planetary ores for oxygen and metallurgically important metals
The utilization of a cold or nonequilibrium plasma in chlorination processing is discussed. Titanium dioxide (TiO2) was successfully chlorinated at temperatures between 700 and 900 C without the aid of carbon. In addition to these initial experiments, a technique was developed for determining the temperature of a specimen in a plasma. Development of that technique has required evaluating the emissivity of TiO2, ZrO2, and FeOTiO2 and analyzing the specimen temperature in a plasma as a function of both power absorbed by the plasma and the pressure of the plasma. The mass spectrometer was also calibrated with TiCl4 and CCl4 vapor
LHCb pentaquarks in constituent quark models
The recently discovered and states at LHCb have
masses close to the and thresholds,
respectively, which suggest that they may have significant meson-baryon
molecular components. We analyze these states in the framework of a constituent
quark model which has been applied to a wide range of hadronic observables,
being the model parameters, therefore, completely constrained.
The and are studied as molecular states composed
by charmed baryons and open charm mesons. Several bound states with the proper
binding energy are found in the and
channels. We discuss the possible assignments of these states from their decay
widths. Moreover, two more states are predicted, associated with the and thresholds.Comment: 5 pages, 2 table
Heavy mesons in the Quark Model
Since the discovery of the , the quark model was very successful in
describing the spectrum and properties of heavy mesons including only
components. However since 2003, with the discovery of the , many
states that can not be accommodated on the naive quark model have been
discovered, and they made unavoidable to include higher Fock components on the
heavy meson states. We will give an overview of the success of the quark model
for heavy mesons and point some of the states that are likely to be more
complicated structures such as meson-meson molecules.Comment: Contribution to the Proceedings of the 15th International Workshop on
Meson Physics - MESON201
Puzzles in quarkonium hadronic transitions with two pion emission
The anomalously large rates of some hadronic transitions from quarkonium are
studied using QCD multipole expansion (QCDME) in the framework of a constituent
quark model which has been successful in describing hadronic phenomenology. The
hybrid intermediate states needed in the QCDME method are calculated in a
natural extension of our constituent quark model based on the Quark Confining
String (QCS) scheme. Some of the anomalies are explained due to the presence of
an hybrid state with a mass near the mass of the decaying resonance whereas
other are justified by the presence of molecular components in the wave
function. Some unexpected results are pointed out.Comment: Conference proceedings of the XI Quark Confinement and the Hadron
Spectrum (CONFINEMENT XI). Saint Petersburg (Russia) from 8 to 12 September
201
The X(3872) and other possible molecular states
We perform a coupled channel calculation of the and sectors
in the framework of a constituent quark model. The interaction for the
states is obtained using the Resonant Group Method (RGM) and the underlying
quark interaction model. The coupling with the two quark system is performed
using the model. The X(3872) is found as a molecular state with a
sizable component. A comparison with Belle and BaBar data has been
done, finding a good agreement. Other possible molecular molecular states are
discussed.Comment: 5 pages, 5 figures, Proceedings to the Hadron 2009 - XIII
International Conference on Hadron Spectroscopy, Florida State University
(USA
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