29,741 research outputs found
Immature dendritic cells induce hyporesponsiveness to alloantigens in vitro and prolong mouse cardiac allograft survival
Recommended from our members
Experimental and Numerical Investigation on Progressive Collapse Resistance of Post-tensioned Precast Concrete Beam-Column Sub-assemblages
In this paper, four 1/2 scaled precast concrete (PC) beam-column sub-assemblages with high performance connection were tested under push-down loading procedure to study the load resisting mechanism of PC frames subjected to different column removal scenarios. The parameters investigated include the location of column removal and effective prestress in tendons. The test results indicated that the failure modes of unbonded post-tensioned precast concrete (PTPC) frames were different from that of reinforced concrete (RC) frames: no cracks formed in the beams and wide opening formed near the beam to column interfaces. For specimens without overhanging beams, the failure of side column was eccentric compression failure. Moreover, the load resisting mechanisms in PC frames were significantly different from that of RC frames: the compressive arch action (CAA) developed in concrete during column removal was mainly due to actively applied pre-compressive stress in the concrete; CAA will not vanish when severe crush in concrete occurred. Thus, it may provide negative contribution for load resistance when the displacement exceeds one-beam depth; the tensile force developed in the tendons could provide catenary action from the beginning of the test. Moreover, to deeper understand the behavior of tested specimens, numerical analyses were carried out. The effects of concrete strength, axial compression ratio at side columns, and loading approaches on the behavior of the sub-assemblages were also investigated based on validated numerical analysis
A wall interference assessment/correction system
A Wall Signature method, the Hackett method, has been selected to be adapted for the 12-ft Wind Tunnel wall interference assessment/correction (WIAC) system in the present phase. This method uses limited measurements of the static pressure at the wall, in conjunction with the solid wall boundary condition, to determine the strength and distribution of singularities representing the test article. The singularities are used in turn for estimating wall interferences at the model location. The Wall Signature method will be formulated for application to the unique geometry of the 12-ft Tunnel. The development and implementation of a working prototype will be completed, delivered and documented with a software manual. The WIAC code will be validated by conducting numerically simulated experiments rather than actual wind tunnel experiments. The simulations will be used to generate both free-air and confined wind-tunnel flow fields for each of the test articles over a range of test configurations. Specifically, the pressure signature at the test section wall will be computed for the tunnel case to provide the simulated 'measured' data. These data will serve as the input for the WIAC method-Wall Signature method. The performance of the WIAC method then may be evaluated by comparing the corrected parameters with those for the free-air simulation. Each set of wind tunnel/test article numerical simulations provides data to validate the WIAC method. A numerical wind tunnel test simulation is initiated to validate the WIAC methods developed in the project. In the present reported period, the blockage correction has been developed and implemented for a rectangular tunnel as well as the 12-ft Pressure Tunnel. An improved wall interference assessment and correction method for three-dimensional wind tunnel testing is presented in the appendix
Fluctuation of the Initial Conditions and Its Consequences on Some Observables
We show effects of the event-by-event fluctuation of the initial conditions
(IC) in hydrodynamic description of high-energy nuclear collisions on some
observables. Such IC produce not only fluctuations in observables but, due to
their bumpy structure, several non-trivial effects appear. They enhance
production of isotropically distributed high-pT particles, making v2 smaller
there. Also, they reduce v2 in the forward and backward regions where the
global matter density is smaller, so where such effects become more
efficacious. They may also produce the so-called ridge effect in the two
large-pT particle correlation.Comment: 6 pages, 6 figures, presented at the IV Workshop on Particle
Correlations and Femtoscopy (WPCF2008), Krakow, Poland, 11-14 Sep 200
Properties of solutions of stochastic differential equations driven by the G-Brownian motion
In this paper, we study the differentiability of solutions of stochastic
differential equations driven by the -Brownian motion with respect to the
initial data and the parameter. In addition, the stability of solutions of
stochastic differential equations driven by the -Brownian motion is
obtained
Fermi surface topology and low-lying quasiparticle structure of magnetically ordered Fe1+xTe
We report the first photoemission study of Fe1+xTe - the host compound of the
newly discovered iron-chalcogenide superconductors. Our results reveal a pair
of nearly electron- hole compensated Fermi pockets, strong Fermi velocity
renormalization and an absence of a spin-density-wave gap. A shadow hole pocket
is observed at the "X"-point of the Brillouin zone which is consistent with a
long-range ordered magneto-structural groundstate. No signature of Fermi
surface nesting instability associated with Q= pi(1/2, 1/2) is observed. Our
results collectively reveal that the Fe1+xTe series is dramatically different
from the undoped phases of the high Tc pnictides and likely harbor unusual
mechanism for superconductivity and quantum magnetic order.Comment: 5 pages, 4 Figures; Submitted to Phys. Rev. Lett. (2009
Spin dynamics of electrons in the first excited subband of a high-mobility low-density 2D electron system
We report on time-resolved Kerr rotation measurements of spin coherence of
electrons in the first excited subband of a high-mobility low-density
two-dimensional electron system in a GaAs/Al0.35Ga0.65As heterostructure. While
the transverse spin lifetime (T2*) of electrons decreases monotonically with
increasing magnetic field, it has a non-monotonic dependence on the
temperature, with a peak value of 596 ps at 36 K, indicating the effect of
inter-subband electron-electron scattering on the electron spin relaxation. The
spin lifetime may be long enough for potential device application with
electrons in excited subbands
A wall interference assessment/correction system
A Wall Signature method originally developed by Hackett has been selected to be adapted for the Ames 12-ft Wind Tunnel WIAC system in the project. This method uses limited measurements of the static pressure at the wall, in conjunction with the solid wall boundary condition, to determine the strength and distribution of singularities representing the test article. The singularities are used in turn for estimating blockage wall interference. The lifting interference will be treated separately by representing in a horseshoe vortex system for the model's lifting effects. The development and implementation of a working prototype will be completed, delivered and documented with a software manual. The WIAC code will be validated by conducting numerically simulated experiments rather than actual wind tunnel experiments. The simulations will be used to generate both free-air and confined wind-tunnel flow fields for each of the test articles over a range of test configurations. Specifically, the pressure signature at the test section wall will be computed for the tunnel case to provide the simulated 'measured' data. These data will serve as the input for the WIAC method--Wall Signature method. The performance of the WIAC method then may be evaluated by comparing the corrected data with those of the free-air simulation
- …