8,951 research outputs found
Influence of nucleonic motion in Relativistic Fermi Gas inclusive responses
Impulsive hadronic descriptions of electroweak processes in nuclei involve
two distinctly different elements: one stems from the nuclear many-body physics
--- the medium --- which is rather similar for the various inclusive response
functions, and the other embodies the responses of the hadrons themselves to
the electroweak probe and varies with the channel selected. In this letter we
investigate within the context of the relativistic Fermi gas in both the
quasi-elastic and regimes the interplay between these two
elements. Specifically, we focus on expansions in the one small parameter in
the problem, namely, the momentum of a nucleon in the initial wave function
compared with the hadronic scale, the nucleon mass. Both parity-conserving and
-violating inclusive responses are studied and the interplay between
longitudinal () and transverse ( and ) contributions is highlighted.Comment: 11 pages, 1 figur
Prediction of pressure drop in multiphase horizontal pipe flow
Empirical correlations were tested against reliable two phase pipe flow data for the prediction of pressure drop. Correlations are recommended for the prediction with stratified and annular type flows. When these correlations were adapted to three phase gaswater-oil pipe flow in general they predicted for intermittent slug type flows. Momentum balance models could not be successfully adapted to the prediction of pipe three phase pressure drop
USSR Space Life Sciences Digest
Research in exobiology, life sciences technology, space biology, and space medicine and physiology, primarily using data gathered on the Salyut 6 orbital space station, is reported. Methods for predicting, diagnosing, and preventing the effects of weightlessness are discussed. Psychological factors are discussed. The effects of space flight on plants and animals are reported. Bioinstrumentation advances are noted
Thermodynamic inequalities in superfluid
We investigate general thermodynamic stability conditions for the superfluid.
This analysis is performed in an extended space of thermodynamic variables
containing (along with the usual thermodynamic coordinates such as pressure and
temperature) superfluid velocity and momentum density. The stability conditions
lead to thermodynamic inequalities which replace the Landau superfluidity
criterion at finite temperatures.Comment: 7 pages, 1 figur
Nuclear response functions for the N-N*(1440) transition
Parity-conserving and -violating response functions are computed for the
inclusive electroexcitation of the N*(1440)(Roper) resonance in nuclear matter
modeled as a relativistic Fermi gas. Using various empirical parameterizations
and theoretical models of the N-N*(1440) transition form factors, the
sensitivity of the response functions to details of the structure of the Roper
resonance is investigated. The possibility of disentangling this resonance from
the contribution of Delta electroproduction in nuclei is addressed. Finally,
the contributions of the Roper resonance to the longitudinal scaling function
and to the Coulomb sum rule are also explored.Comment: 25 pages, 10 figures. Minor changes in the Introduction. Accepted in
NP
Stationary and non-stationary fluid flow of a Bose-Einstein condensate through a penetrable barrier
We experimentally study the fluid flow induced by a broad, penetrable barrier
moving through an elongated dilute gaseous Bose-Einstein condensate. The
barrier is created by a laser beam swept through the condensate, and the
resulting dipole potential can be either attractive or repulsive. We examine
both cases and find regimes of stable and unstable fluid flow: At slow speeds
of the barrier, the fluid flow is stationary due to the superfluidity of the
condensate. At intermediate speeds, we observe a non-stationary regime in which
the condensate gets filled with dark solitons. At faster speeds, soliton
formation completely ceases and a remarkable absence of excitation in the
condensate is seen again.Comment: 4 pages, 4 figure
Lead contamination risks from imported candies: Developing a protocol to test for lead in candy products using the X-ray flouresence instrument
The problem of lead in candies imported from Latin America and or Thailand is an important public health issue. These candies come from a number of sources, with lead often being present when tamarind or chili pepper is used as an ingredient. Currently, it is expensive and time consuming for heath protection agencies to test candy that has entered the consumer market in the United States. Hence children may potentially be exposed to lead contamination. If community health agencies had access to XRF technology, health agencies could quickly determine if specific candies contain lead. To date, there has not been a protocol developed using the XRF instrument to test candies. Herein, are details of the newly developed XRF procedure for testing candies and comparing the XRF results against EPA Graphite Furnace results. Additionally a comparison of candy collected from a local Las Vegas middle school against the current California toxic treat index list is provided. Details of a community health lead education program which includes the results of a student candy consumption survey are presented. The protocol explained herein will provide an important resource for both researchers and public health officials collaborating in the effort to protect their communities from exposure to lead contamination
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