19,347 research outputs found
Polarization Measurements and the Pairing Gap in the Universal Regime
We analyze recent cold-atom experiments on imbalanced Fermi systems using a
minimal model with a BCS-like superfluid phase coexisting with a normal phase.
This model is used to extract the T=0 pairing gap in the fully paired
superfluid state. The recently measured particle density profiles are in good
agreement with the theoretical predictions obtained from the universal
parameters from previous Quantum Monte Carlo calculations. We find that the T=0
pairing gap is greater than 0.4 times the Fermi energy , with a preferred
value of . The ratio of the pairing gap to the
Fermi Energy is larger here than in any other system of strongly-paired
fermions in which individual pairs are unbound.Comment: 4 pages, 3 figures. Revised verison includes cosmetic changes to the
text and figures. One reference adde
THERMTRAJ: A FORTRAN program to compute the trajectory and gas film temperatures of zero pressure balloons
A FORTRAN computer program called THERMTRAJ is presented which can be used to compute the trajectory of high altitude scientific zero pressure balloons from launch through all subsequent phases of the balloon flight. In addition, balloon gas and film temperatures can be computed at every point of the flight. The program has the ability to account for ballasting, changes in cloud cover, variable atmospheric temperature profiles, and both unconditional valving and scheduled valving of the balloon gas. The program was verified for an extensive range of balloon sizes (from 0.5 to 41.47 million cubic feet). Instructions on program usage, listing of the program source deck, input data and printed and plotted output for a verification case are included
A unified thermal and vertical trajectory model for the prediction of high altitude balloon performance
A computer model for the prediction of the trajectory and thermal behavior of zero-pressure high altitude balloon was developed. In accord with flight data, the model permits radiative emission and absorption of the lifting gas and daytime gas temperatures above that of the balloon film. It also includes ballasting, venting, and valving. Predictions obtained with the model are compared with flight data from several flights and newly discovered features are discussed
An experimental study of the buckling of complete spherical shells
Buckling of complete spherical shells to examine Tsien energy hypothesi
Space environment operation of experimental hydrazine reactors Final report
Correlation of low temperature high vacuum hydrazine ignition properties of Shell 405 catalyst with concentration of adsorbed gase
Variational Monte Carlo Calculations of H and He with a relativistic Hamiltonian - II
In relativistic Hamiltonians the two-nucleon interaction is expressed as a
sum of , the interaction in the rest frame,
and the ``boost interaction'' which depends upon the
total momentum and vanishes in the rest frame. The
can be regarded as a sum of four terms: , ,
and ; the first three originate from the
relativistic energy-momentum relation, Lorentz contraction and Thomas
precession, while the last is purely quantum. The contributions of and have been previously calculated with the
variational Monte Carlo method for H and He. In this brief note we
report the results of similar calculations for the contributions of and . These are found to be rather small.Comment: 7 pages, P-94-09-07
Analysis of shell-type structures subjected to time-dependent mechanical and thermal loading
A general mathematical model and solution methodologies are being developed for analyzing structural response of thin, metallic shell-type structures under large transient, cyclic, or static thermomechanical loads. Among the system responses, which were associated with these load conditions, were thermal buckling, creep buckling, and ratcheting. Thus, geometric as well as material-type nonlinearities (of high order) can be anticipated and must be considered in the development of the mathematical model. Furthermore, this must also be accommodated in the solution process
Non-isothermal elastoviscoplastic analysis of planar curved beams
The development of a general mathematical model and solution methodologies, to examine the behavior of thin structural elements such as beams, rings, and arches, subjected to large nonisothermal elastoviscoplastic deformations is presented. Thus, geometric as well as material type nonlinearities of higher order are present in the analysis. For this purpose a complete true abinito rate theory of kinematics and kinetics for thin bodies, without any restriction on the magnitude of the transformation is presented. A previously formulated elasto-thermo-viscoplastic material constitutive law is employed in the analysis. The methodology is demonstrated through three different straight and curved beams problems
Analysis of shell type structures subjected to time dependent mechanical and thermal loading
A general mathematical model and solution methodologies for analyzing structural response of thin, metallic shell-type structures under large transient, cyclic or static thermomechanical loads is considered. Among the system responses, which are associated with these load conditions, are thermal buckling, creep buckling and ratchetting. Thus, geometric as well as material-type nonlinearities (of high order) can be anticipated and must be considered in the development of the mathematical model
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