505 research outputs found
Damage in textile laminates of various inter-ply shift
Deformation mechanisms and failure of textile laminates are strongly affected by inter-layer configurations – a mutual shift of the plies. To model it within a traditional framework, one must construct a representative volume element (RVE), which includes all the plies. This is a time consuming and computationally expensive work. As an alternative, the paper suggests boundary conditions (BC) imitating the interaction with the surrounding non-periodic media. This makes possible analysis on a single unit cell of one ply. The proposed BC respect inter-ply configurations, account for the number of plies, distinguish the ply position, and reproduce the meso stress state with a good accuracy. The BC are constructed through (1) averaging of the known periodic solutions with respect to the ply shifts, (2) separation of the solution to the outer and inner ply cases, (3) energy equilibrium of heterogeneous and effective media. The unit cell finite element (FE) modelling is validated by reference full scale solution on the entire laminate
Fibre distribution inside yarns of textile composite: gemetrical and FE modelling
This article addresses the experimental investigation and modelling of the uneven fibre distribution inside yarns of a textile composite. The test data is given for the tri-axial carbon-fibre braid; a considerable irregularity is revealed for the fibre distribution along and across the yarns. The importance of this effect for the damage resistance is illustrated with a simple finite-element (FE) model. The geometrical modelling of the internal geometry is also discussed
Complex structural-tectonic zoning of the north-eastern part
The large amount of geological and geophysical data obtained in recent decades for the north-eastern part of the Barents Sea shelf makes their visual comparative analysis difficult, and the use of automated classification methods, in particular, multidimensional statistics, become relevant.
The perspectives of the statistical approach to the processing and interpretation of multi-sign geological and geophysical information are considered. The objective performance of the method of identifying classes (tectonic structures) within the studied area is determined by statistically justified methods that are independent of the subjective factor. The structural-tectonic schemes for reflecting horizons are clarified, at the level of which the main stages of large-scale tectonic reorganizations occur
Superradiant and Aharonov-Bohm effect for the quantum ring exciton
The Aharonov-Bohm and superradiant effect on the redaitive decay rate of an
exciton in a quantum ring is studied. With the increasing of ring radius, the
exciton decay rate is enhanced by superradiance, while the amplitude of AB
oscillation is decreased. The competition between these two effects is shown
explicitly and may be observable in time-resolved exeriments.Comment: 4 pages, 2 figures, to appear in Solid State Communications (2004
Orbit equivalence rigidity for ergodic actions of the mapping class group
We establish orbit equivalence rigidity for any ergodic, essentially free and
measure-preserving action on a standard Borel space with a finite positive
measure of the mapping class group for a compact orientable surface with higher
complexity. We prove similar rigidity results for a finite direct product of
mapping class groups as well.Comment: 11 pages, title changed, a part of contents remove
Ground-state properties of the Rokhsar-Kivelson dimer model on the triangular lattice
We explicitly show that the Rokhsar-Kivelson dimer model on the triangular
lattice is a liquid with topological order. Using the Pfaffian technique, we
prove that the difference in local properties between the two topologically
degenerate ground states on the cylinders and on the tori decreases
exponentially with the system size. We compute the relevant correlation length
and show that it equals the correlation length of the vison operator.Comment: 10 pages, 9 figure
On the pion electroproduction amplitude
We analyze amplitudes for the pion electroproduction on proton derived from
Lagrangians based on the local chiral SU(2) x SU(2) symmetries. We show that
such amplitudes do contain information on the nucleon axial form factor F_A in
both soft and hard pion regimes. This result invalidates recent Haberzettl's
claim that the pion electroproduction at threshold cannot be used to extract
any information regarding F_A.Comment: 14 pages, 6 figures, revised version, accepted for publication in
Phys. Rev.
Camphor and Eucalyptol-Anticandidal Spectrum, Antivirulence Effect, Efflux Pumps Interference and Cytotoxicity.
Candidaalbicans represents one of the most common fungal pathogens. Due to its increasing incidence and the poor efficacy of available antifungals, finding novel antifungal molecules is of great importance. Camphor and eucalyptol are bioactive terpenoid plant constituents and their antifungal properties have been explored previously. In this study, we examined their ability to inhibit the growth of different Candida species in suspension and biofilm, to block hyphal transition along with their impact on genes encoding for efflux pumps (CDR1 and CDR2), ergosterol biosynthesis (ERG11), and cytotoxicity to primary liver cells. Camphor showed excellent antifungal activity with a minimal inhibitory concentration of 0.125-0.35 mg/mL while eucalyptol was active in the range of 2-23 mg/mL. The results showed camphor's potential to reduce fungal virulence traits, that is, biofilm establishment and hyphae formation. On the other hand, camphor and eucalyptol treatments upregulated CDR1;CDR2 was positively regulated after eucalyptol application while camphor downregulated it. Neither had an impact on ERG11 expression. The beneficial antifungal activities of camphor were achieved with an amount that was non-toxic to porcine liver cells, making it a promising antifungal compound for future development. The antifungal concentration of eucalyptol caused cytotoxic effects and increased expression of efflux pump genes, which suggests that it is an unsuitable antifungal candidate
Radiative corrections to the excitonic molecule state in GaAs microcavities
The optical properties of excitonic molecules (XXs) in GaAs-based quantum
well microcavities (MCs) are studied, both theoretically and experimentally. We
show that the radiative corrections to the XX state, the Lamb shift
and radiative width , are
large, about of the molecule binding energy , and
definitely cannot be neglected. The optics of excitonic molecules is dominated
by the in-plane resonant dissociation of the molecules into outgoing
1-mode and 0-mode cavity polaritons. The later decay channel,
``excitonic molecule 0-mode polariton + 0-mode
polariton'', deals with the short-wavelength MC polaritons invisible in
standard optical experiments, i.e., refers to ``hidden'' optics of
microcavities. By using transient four-wave mixing and pump-probe
spectroscopies, we infer that the radiative width, associated with excitonic
molecules of the binding energy meV, is
meV in the microcavities and
meV in a reference GaAs single quantum
well (QW). We show that for our high-quality quasi-two-dimensional
nanostructures the limit, relevant to the XX states, holds at
temperatures below 10 K, and that the bipolariton model of excitonic molecules
explains quantitatively and self-consistently the measured XX radiative widths.
We also find and characterize two critical points in the dependence of the
radiative corrections against the microcavity detuning, and propose to use the
critical points for high-precision measurements of the molecule bindingenergy
and microcavity Rabi splitting.Comment: 16 pages, 11 figures, accepted for publication in Phys. Rev.
“Electron-10” higt voltage accselerator for double-sided irradiation of flexible materials
The main goals we pursued during the accelerator design and development were to develop a compact self-shielded device for flexible materials irradiation in one pass which might be installed by a Customer into common industrial premises not equipped with any lifting devices. These goals were successfully achieved in the “Electron-10” accelerator design
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