32,886 research outputs found
Beyond Fermi pseudopotential: a modified GP equation
We present an effective potential and the corresponding modified
Gross-Pitaevskii equation that account for the energy dependence of the
two-body scattering amplitude through an effective-range expansion. For the
ground state energy of a trapped condensate, the theory leads to what we call a
shape-dependent confinement correction that improves agreements with diffusion
Monte Carlo calculations. The theory illustrates, for relatively strong
confinement and/or high density, how the shape dependence on atom-atom
interaction can come into play in a many-atom quantum system.Comment: 8 pages, 5 figure
Almost Periodic Passive Tracer Dispersion
The authors investigate the impact of external sources on the pattern
formation of concentration profiles of passive tracers in a two-dimensional
shear flow. By using the pullback attractor technique for the associated
nonautonomous dynamical system, it is shown that a unique time-almost periodic
concentration profile exists for time-almost periodic external source.Comment: latex fil
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Performance of bolted steel-beam to CFST-column joints using stiffened angles in column-removal scenario
This paper presents three experimental investigations on the performance of steel-beam to CFST-column joints using stiffened angle, long bolts and fin plate under a middle column removal scenario. Three specimens were designed and tested. The failure modes and catenary action are investigated in detail. The test results show that increasing the angle plate thickness at the joint could not only improve its performance significantly, but also trigger an early formation of catenary action. Increasing the length of short-limb had influence on the deformation ability of the proposed joint, rather than the load capacity. The buckling of stiffeners could prevent the brittle failure of the joints. With the contribution of catenary action, the joint shows much higher rotation capacities than that required in DoD design guidance. The initial stiffness of the joint was calculated using an analytical model with consideration of bolt pretension. Good agreement to the test results is achieved. A numerical analysis is also carried out, whose results show that adding additional row of bolts would improve the redundancy of the joint under column loss. An equivalent dynamic response evaluation of the joints was also performed. The results show that dynamic amplification coefficient should be worked out considering catenary action under large deformation
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