195 research outputs found
Water bath calorimetric study of excess heat generation in 'resonant transfer' plasmas
Water bath calorimetry was used to demonstrate one more peculiar phenomenon
associated with a certain class of mixed gas plasmas termed resonant transfer,
or RT plasmas. Specifically, He/H2 (10%) (500 mTorr), Ar/H2 (10%) (500 mTorr),
and H2O(g) (500 and 200 mTorr) plasmas generated with an Evenson microwave
cavity consistently yielded on the order of 50% more heat than non RT plasma
(controls) such as He, Kr, Kr/H2 (10%), under identical conditions of gas flow,
pressure, and microwave operating conditions. The excess power density of RT
plasmas was of the order 10 W / cm-3. In earlier studies with these same RT
plasmas it was demonstrated that other unusual features were present including
dramatic broadening of the hydrogen Balmer series lines, unique vacuum
ultraviolet (VUV) lines, and in the case of water plasmas, population inversion
of the hydrogen excited states. Both the current results and the earlier
results are completely consistent with the existence of a hitherto unknown
exothermic chemical reaction, such as that predicted by Mills, occurring in RT
plasmas.Comment: 30 pages, 2 tables, 5 figure
Weak Hyperon Production in ep Scattering
We study the kinematics and cross section of the scattering process . The cross section is expressed in terms of complex
form factors characterizing the hadron vertices. We estimate the cross section
for small momentum transfer using known experimental information. To first
order in the momentum transfer, we obtain a model independent result for the
photon-exchange part of the cross section, which is completely determined by
the decay width . For the kinematics of
the parity violation experiment at MAMI, this first order result gives rise to
a ratio of
. The
-exchange and interference parts give much smaller contributions due to
the suppression of the flavor changing weak neutral current in the standard
model. Feasibility of the experimental measurement is briefly discussed.Comment: ReVTeX, 9 pages, one figure embedde
Cultivation of the microalga, Chlorella pyrenoidosa, in biogas wastewater
Biogas wastewater is always a problem as a result of its extremely high concentrations of nitrogen and phosphorus, which is the main reason for the eutrophication of the surrounding water. The microalga, Chlorella pyrenoidosa, can utilize the nitrogen and phosphorus in wastewater for its growth. Therefore, the microalga was introduced to be cultivated in the biogas wastewater, which could not only bioremediate the wastewater, but also produce plenty of the microalga biomass that could be used for the exploitation of fertilizers, feed additives and biofuels. This study showed that the microalga, C. pyrenoidosa could grow well in the biogas wastewater under optimal condition: initial cell density of 0.15 (OD680), pH 8 and illumination intensity of 10000 LX. Under the optimal condition, the dry cell weight of the microalgae reached 0.1 g/L after cultivation in the wastewater for fourteen (14) days; in the meantime, the microalga also removed 71.8% of phosphorus, 100% of ammoniacal nitrogen (NH4+-N), 52.8% of nitrate nitrogen (NO3-N) and 23.0% of nitrite nitrogen (NO2-N) from the biogas wastewater, suggesting that the cultivation of C. pyrenoidosa in biogas wastewater would be efficient for the treatment of wastewater. This study also provided a low-cost way to produce the microalga and its relevant products.Key words: Chlorella pyrenoidosa, biogas wastewater, cultivation, phosphorus, nitrogen
Interference Fragmentation Functions and the Nucleon's Transversity
We introduce twist-two quark interference fragmentation functions in helicity
density matrix formalism and study their physical implications. We show how the
nucleon's transversity distribution can be probed through the final state
interaction between two mesons (, , or ) produced
in the current fragmentation region in deep inelastic scattering on a
transversely polarized nucleon.Comment: Final version to be published in Phys. Rev. Let
Relations among Zero Momentum Correlators for Heavy-Light Systems in QCD
Relations connecting various zero momentum correlators of interpolating
fields for pseudoscalar and scalar channel, containing one heavy and one light
quark field, are derived from the Euclidean space formulation of the QCD
functional integral. These relations may serve as constraints on the
phenomenological models or approaches motivated from QCD, and suggest a method
to extract the chiral quark condensates. It is also found that the correlator
for pseudoscalar channel differs from that for scalar channel even in the large
heavy quark mass limit.Comment: 9 pages in ReVTeX, UMD preprint #94-14
Interference Fragmentation Functions and Valence Quark Spin Distributions in the Nucleon
We explore further applications of the twist-two quark interference
fragmentation functions introduced earlier. We show that semi-inclusive
production of two pions in the current fragmentation region in deep inelastic
scattering of a longitudinally polarized electron on a longitudinally polarized
nucleon can provide a probe of the valence quark spin (or helicity difference)
distribution in the nucleon.Comment: 6 pages ReVTeX, one figure embedded An error in the earlier version
is fixe
In-medium relativistic kinetic theory and nucleon-meson systems
Within the model of coupled nucleon-meson systems, a
generalized relativistic Lenard--Balescu--equation is presented resulting from
a relativistic random phase approximation (RRPA). This provides a systematic
derivation of relativistic transport equations in the frame of nonequilibrium
Green's function technique including medium effects as well as flucuation
effects. It contains all possible processes due to one meson exchange and
special attention is kept to the off--shell character of the particles. As a
new feature of many particle effects, processes are possible which can be
interpreted as particle creation and annihilation due to in-medium one meson
exchange. In-medium cross sections are obtained from the generalized derivation
of collision integrals, which possess complete crossing symmetries.Comment: See nucl-th/9310032 for revised version which the authors
incompetently resubmitted rather than correctly replacing thi
QCD Sum Rules for Hyperons in Nuclear Matter
Within finite-density QCD sum-rule approach we investigate the self-energies
of hyperons propagating in nuclear matter from a correlator of
interpolating fields evaluated in the nuclear matter ground state. We
find that the Lorentz vector self-energy of the is similar to the
nucleon vector self-energy. The magnitude of Lorentz scalar self-energy of the
is also close to the corresponding value for nucleon; however, this
prediction is sensitive to the strangeness content of the nucleon and to the
assumed density dependence of certain four-quark condensate. The scalar and
vector self-energies tend to cancel, but not completely. The implications for
the couplings of to the scalar and vector mesons in nuclear matter and
for the spin-orbit force in a finite nucleus are discussed.Comment: 20 pages in revtex, 6 figures available under request as ps files,
UMD preprint #94--11
New QCD Sum Rules for Nucleon Tensor Charge
Two new QCD sum rules for nucleon tensor charge are derived from a mixed
correlator of spin-1/2 and spin-3/2 nucleon interpolating fields. These sum
rules are analyzed along with a sum rule obtained from the usual correlator of
a general spin-1/2 nucleon interpolating field. The validity and reliability of
the sum rules are examined by monitoring the contaminations arising from the
transitions and continuum and the convergence of the operator product
expansion. Valid sum rules are identified and their predictions are presented.
It is found that the vacuum tensor susceptibility induced by the external field
plays an important role in determining both the validity and predictions of the
sum rules. The uncertainties associated with the sum-rule predictions are also
discussed.Comment: RevTeX, 20 pages, 5 figures embedde
Modified Quark-Meson Coupling Model for Nuclear Matter
The quark-meson coupling model for nuclear matter, which describes nuclear
matter as non-overlapping MIT bags bound by the self-consistent exchange of
scalar and vector mesons, is modified by introducing medium modification of the
bag constant. We model the density dependence of the bag constant in two
different ways: one invokes a direct coupling of the bag constant to the scalar
meson field, and the other relates the bag constant to the in-medium nucleon
mass. Both models feature a decreasing bag constant with increasing density. We
find that when the bag constant is significantly reduced in nuclear medium with
respect to its free-space value, large canceling isoscalar Lorentz scalar and
vector potentials for the nucleon in nuclear matter emerge naturally. Such
potentials are comparable to those suggested by relativistic nuclear
phenomenology and finite-density QCD sum rules. This suggests that the
reduction of bag constant in nuclear medium may play an important role in low-
and medium-energy nuclear physics.Comment: Part of the text is reordered, revised version to appear in Phys.
Rev. C. 19 pages, ReVTeX, 4 figures embedde
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