60,023 research outputs found
Application of conformal mapping to diffraction and scattering problems
Integral equation method based on conformal mapping applied to scattering and diffraction problems of plane waves by infinite cylinder with arbitrary cross sectio
Influence of aggregate size and fraction on shrinkage induced micro-cracking of mortar and concrete
In this paper, the influence of aggregate size and volume fraction on
shrinkage induced micro-cracking and permeability of concrete and mortar was
investigated. Nonlinear finite element analyses of model concrete and mortar
specimens were performed. The aggregate diameter was varied between 2 and 16
mm. Furthermore, a range of volume fractions between 0.1 and 0.5 was studied.
The nonlinear analyses were based on a 2D lattice approach in which aggregates
were simplified as monosized cylindrical inclusions. The analysis results were
interpreted by means of crack width and change of permeability. The results
show that increasing aggregate diameter (at equal volume fraction) and
decreasing volume fraction (at equal aggregate diameter) greatly increases
permeability.Comment: 12th International Conference on Fracture (ICF 12
model with Hopf term and fractional spin statistics
We reconsider the model with the Hopf term by using the
Batalin-Fradkin-Tyutin (BFT) scheme, which is an improved version of the Dirac
quantization method. We also perform a semi-classical quantization of the
topological charge Q sector by exploiting the collective coordinates to
explicitly show the fractional spin statistics.Comment: 15 page
Radiative neutron capture on a proton at BBN energies
The total cross section for radiative neutron capture on a proton, , is evaluated at big bang nucleosynthesis (BBN) energies. The
electromagnetic transition amplitudes are calculated up to next-to leading
order within the framework of pionless effective field theory with dibaryon
fields. We also calculate the cross section and the photon
analyzing power for the process from the amplitudes. The
values of low energy constants that appear in the amplitudes are estimated by a
Markov Chain Monte Carlo analysis using the relevant low energy experimental
data. Our result agrees well with those of other theoretical calculations
except for the cross section at some energies estimated by an
R-matrix analysis. We also study the uncertainties in our estimation of the
cross section at relevant BBN energies and find that the
estimated cross section is reliable to within 1% error.Comment: 21 pages and 12 eps figures; 6 eps figures and 2 references added,
and accepted for publication in Phys. Rev.
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