904 research outputs found
A fully CNN based fingerprint recognition system
In this paper, a fully cellular neural networks (CNN) based fingerprint recognition system is introduced. The system includes a preprocessing phase where the input fingerprint image is enhanced and a recognition phase where the enhanced fingerprint image is matched with the fingerprints in the database. Both preprocessing and recognition phases are realized by means of CNN approaches. A novel application of skeletonization method is used to perform ridgeline thinning which improves the quality of the extracted lines for further processing, and hence increases the overall system performance
The spectral shift function and Levinson's theorem for quantum star graphs
We consider the Schr\"odinger operator on a star shaped graph with edges
joined at a single vertex. We derive an expression for the trace of the
difference of the perturbed and unperturbed resolvent in terms of a Wronskian.
This leads to representations for the perturbation determinant and the spectral
shift function, and to an analog of Levinson's formula
Monte-Carlo simulation of neutron transmission through nanocomposite materials for neutron-optics applications
Nanocomposites enable us to tune parameters that are crucial for use of such
materials for neutron-optics applications such as diffraction gratings by
careful choice of properties such as species (isotope) and concentration of
contained nanoparticles. Nanocomposites for neutron optics have so far
successfully been deployed in protonated form, containing high amounts of H
atoms, which exhibit rather strong neutron absorption and incoherent
scattering. At a future stage of development, chemicals containing H could
be replaced by components with more favourable isotopes, such as H or
F. In this note, we present results of Monte-Carlo simulations of the
transmissivity of various nanocomposite materials for thermal and very-cold
neutron spectra. The results are compared to experimental transmission data.
Our simulation results for deuterated and fluorinated nanocomposite materials
predict a decrease of absorption- and scattering-losses down to about 2 % for
very-cold neutrons.Comment: submitted to NIM
Universal behavior of localization of residue fluctuations in globular proteins
Localization properties of residue fluctuations in globular proteins are
studied theoretically by using the Gaussian network model. Participation ratio
for each residue fluctuation mode is calculated. It is found that the
relationship between participation ratio and frequency is similar for all
globular proteins, indicating a universal behavior in spite of their different
size, shape, and architecture.Comment: 4 pages, 3 figures. To appear in Phys. Rev.
Experimental determination of the roughness functions of marine coatings
The aim of this paper is to determine the roughness functions of different marine coatings, including two novel FOUL-X-SPEL paints and two existing commercial coatings, and two control surfaces, using the overall method of Granville (1987). An extensive series of towing tests of flat plates coated with different antifouling coatings was carried out at the Kelvin Hydrodynamics Laboratory (KHL) of the University of Strathclyde. The tests were designed to examine the as applied drag performances of FOUL-X-SPEL paints and compare them with two existing reference paints and two control surfaces. The surface roughness amplitude parameters of all of the test surfaces were measured using a hull roughness analyser. In total over 150 runs were carried out, including a series of repeat tests designed to quantify the uncertainty in the results. The drag coefficients and roughness function values of each surface were evaluated along with the uncertainty limits
Modeling relaxation and jamming in granular media
We introduce a stochastic microscopic model to investigate the jamming and
reorganization of grains induced by an object moving through a granular medium.
The model reproduces the experimentally observed periodic sawtooth fluctuations
in the jamming force and predicts the period and the power spectrum in terms of
the controllable physical parameters. It also predicts that the avalanche
sizes, defined as the number of displaced grains during a single advance of the
object, follow a power-law, , where the exponent is
independent of the physical parameters
Hysteresis phenomena during melting of an ultrathin lubricant film
The influence of a deformational defect of the shear modulus on the melting of an ultrathin lubricant film was investigated in the framework of the Lorenz model used for describing a viscoelastic medium. It was established that the film can undergo both stepwise and continuous melting. Analysis of the lubricant behavior revealed that there are three modes corresponding to a zero shear stress, a Hookean portion in the loading diagram, and a plastic-flow portion. The hysteresis in the dependences of the stationary shear stress on the strain and the friction surface temperature is examined.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/1621
Thin-Film Metamaterials called Sculptured Thin Films
Morphology and performance are conjointed attributes of metamaterials, of
which sculptured thin films (STFs) are examples. STFs are assemblies of
nanowires that can be fabricated from many different materials, typically via
physical vapor deposition onto rotating substrates. The curvilinear--nanowire
morphology of STFs is determined by the substrate motions during fabrication.
The optical properties, especially, can be tailored by varying the morphology
of STFs. In many cases prototype devices have been fabricated for various
optical, thermal, chemical, and biological applications.Comment: to be published in Proc. ICTP School on Metamaterials (Augsut 2009,
Sibiu, Romania
Linear-nonequilibrium thermodynamics theory for coupled heat and mass transport
Linear-nonequilibrium thermodynamics (LNET) has been used to express the entropy generation and dissipation functions representing the true forces and flows for heat and mass transport in a multicomponent fluid. These forces and flows are introduced into the phenomenological equations to formulate the coupling phenomenon between heat and mass flows. The degree of the coupling is also discussed. In the literature such coupling has been formulated incompletely and sometimes in a confusing manner. The reason for this is the lack of a proper combination of LNET theory with the phenomenological theory. The LNET theory involves identifying the conjugated flows and forces that are related to each other with the phenomenological coefficients that obey the Onsager relations. In doing so, the theory utilizes the dissipation function or the entropy generation equation derived from the Gibbs relation. This derivation assumes that local thermodynamic equilibrium holds for processes not far away from the equilibrium. With this assumption we have used the phenomenological equations relating the conjugated flows and forces defined by the dissipation function of the irreversible transport and rate process. We have expressed the phenomenological equations with the resistance coefficients that are capable of reflecting the extent of the interactions between heat and mass flows. We call this the dissipation-phenomenological equation (DPE) approach, which leads to correct expression for coupled processes, and for the second law analysis
Understanding adhesion at as-deposited interfaces from ab initio thermodynamics of deposition growth: thin-film alumina on titanium carbide
We investigate the chemical composition and adhesion of chemical vapour
deposited thin-film alumina on TiC using and extending a recently proposed
nonequilibrium method of ab initio thermodynamics of deposition growth (AIT-DG)
[Rohrer J and Hyldgaard P 2010 Phys. Rev. B 82 045415]. A previous study of
this system [Rohrer J, Ruberto C and Hyldgaard P 2010 J. Phys.: Condens. Matter
22 015004] found that use of equilibrium thermodynamics leads to predictions of
a non-binding TiC/alumina interface, despite the industrial use as a
wear-resistant coating. This discrepancy between equilibrium theory and
experiment is resolved by the AIT-DG method which predicts interfaces with
strong adhesion. The AIT-DG method combines density functional theory
calculations, rate-equation modelling of the pressure evolution of the
deposition environment and thermochemical data. The AIT-DG method was
previously used to predict prevalent terminations of growing or as-deposited
surfaces of binary materials. Here we extent the method to predict surface and
interface compositions of growing or as-deposited thin films on a substrate and
find that inclusion of the nonequilibrium deposition environment has important
implications for the nature of buried interfaces.Comment: 8 pages, 6 figures, submitted to J. Phys.: Condens. Matte
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