80,287 research outputs found
Behaviour of FRP-to-concrete bonded joints
The bond behaviour between FRP (fibre-reinforced polymer) and concrete is a consideration in the design of FRP strengthening mechanisms for structurally deficient or functionally obsolete concrete structures. In the past, a number of empirical models and fracture mechanics based theoretical models have been proposed for determining the effective bond length and bond strength of FRP sheets/plates bonded to concrete. However, these methods have yielded large discrepancies in the predictions of effective bond length and bond strength. In this paper, the results of an experimental investigation into effective bond length and bond strength are presented. Comparison of experiments results with predictions from three empirical and three fracture mechanics based theoretical models shows that a recently proposed fracture mechanics based local-bond slip model provides a conservative prediction of the effective bond length and an accurate prediction of bond strengt
Comparison of Compression Schemes for CLARA
CLARA (Compact Linear Advanced Research Accelerator)at Daresbury Laboratory
is proposed to be the UK's national FEL test facility. The accelerator will be
a ~250 MeV electron linac capable of producing short, high brightness electron
bunches. The machine comprises a 2.5cell RF photocathode gun, one 2 m and three
5 m normal conducting S-band (2998MHz) accelerating structures and a variable
magnetic compression chicane. CLARA will be used as a test bed for novel FEL
configurations. We present a comparison of acceleration and compression schemes
for the candidate machine layout.Comment: 3 pages, 5 figures, IPAC 201
In-medium electron-nucleon scattering
In-medium nucleon electromagnetic form factors are calculated in the quark
meson coupling model. The form factors are typically found to be suppressed as
the density increases. For example, at normal nuclear density and , the nucleon electric form factors are reduced by approximately 8%
while the magnetic form factors are reduced by only 1 - 2%. These variations
are consistent with current experimental limits but should be tested by more
precise experiments in the near future.Comment: 14 pages, latex, 3 figure
Rotor redesign for a highly loaded 1800 ft/sec tip speed fan. 3: Laser Doppler velocimeter report
Laser Doppler velocimeter (LDV) techniques were employed for testing a highly loaded, 550 m/sec (1800 ft/sec) tip speed, test fan stage, the objective to provide detailed mapping of the upstream, intrablade, and downstream flowfields of the rotor. Intrablade LDV measurements of velocity and flow angle were obtained along four streamlines passing through the leading edge at 45%, 69%, 85%, and 95% span measured from hub to tip, at 100% of design speed, peak efficiency; 100% speed, near surge; and 95% speed, peak efficiency. At the design point, most passages appeared to have a strong leading edge shock, which moved forward with increasing strength near surge and at part speeds. The flow behind the shock was of a complex mixed subsonic and supersonic form. The intrablade flowfields were found to be significantly nonperiodic at 100% design speed, peak efficiency
Three-body recombination in a three-state Fermi gas with widely tunable interactions
We investigate the stability of a three spin state mixture of ultracold
fermionic Li atoms over a range of magnetic fields encompassing three
Feshbach resonances. For most field values, we attribute decay of the atomic
population to three-body processes involving one atom from each spin state and
find that the three-body loss coefficient varies by over four orders of
magnitude. We observe high stability when at least two of the three scattering
lengths are small, rapid loss near the Feshbach resonances, and two unexpected
resonant loss features. At our highest fields, where all pairwise scattering
lengths are approaching , we measure a three-body loss
coefficient and a trend
toward lower decay rates for higher fields indicating that future studies of
color superfluidity and trion formation in a SU(3) symmetric Fermi gas may be
feasible
Higher-Order Corrected Higgs Bosons in FeynHiggs 2.5
Large higher-order corrections enter the Higgs boson sector of the MSSM via
Higgs-boson self-energies. Their effects have to be taken into account for the
correct treatment of loop-corrected Higgs-boson mass eigenstates as external
(on-shell) or internal particles in Feynman diagrams. We review how the loop
corrections, including momentum dependence and imaginary contributions, are
correctly taken into account for external (on-shell) Higgs boson and how
effective couplings can be derived. The proceedures are implemented in the code
FeynHiggs 2.5.Comment: 8 pages, no figures. Two talks given at the LCWS06 March 2006,
Bangalore, Indi
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