A hybrid approach to determining cornea mechanical properties in vivo using a combination of nano-indentation and inverse finite element analysis

This article was published in the serial, Journal of the Mechanical Behavior of Biomedical Materials [© Elsevier]. The definitive version is available at: http://dx.doi.org/10.1016/j.jmbbm.2013.05.016An analysis of the material properties of porcine corneas has been performed. A simple stress relaxation test was performed to determine the viscoelastic properties and a rheological model was built based on the Generalized Maxwell (GM) approach. A validation experiment using nano-indentation showed that an isotropic GM model was insufficient for describing the corneal material behaviour when exposed to a complex stress state. A new technique was proposed for determining the properties, using a combination of nano-indentation experiment, an isotropic and orthotropic GM model and inverse finite element method. The good agreement using this method suggests that this is a promising technique for measuring material properties in vivo and further work should focus on the reliability of the approach in practice

Study on coarsening of Ag3Sn intermetallic compound in the Fe-modified Sn-1Ag-0.5Cu solder alloys

The present study focuses on coarsening of Ag3Sn intermetallic compound in the Sn-1Ag-0.5Cu and Fe-modified Sn-1Ag-0.5Cu solder alloy. The investigations showed that the Ag3Sn intermetallics coarsened rapidly in the Sn-1Ag-0.5Cu solder alloy whereas the Ag3Sn intermetallics were found to be quite stable in the Fe-modified Sn-1Ag-0.5Cu solder alloy. The lattice strain in the Ag3Sn intermetallics and the blocking effect on Ag diffusivity in Sn matrix suggested the possible mechanisms for the coarsening suppression of the Ag3Sn intermetallics in the Fe-modified solder alloy. (C) 2014 Elsevier B.V. All rights reserved

Averaging of random semigroups and quantization

Abstract: The properties of mean values of random variable with values in the set of semigroups of unitary operators are investigated. The mean value of random semigroup has no semigroup property. But it is equivalent in Chernoff sense to the semigroup with generator which is the result of averaging of generators of values of random semigroup. The problem of ambiguity of quantization of Hamiltonian systems is studied by using of semigroup averaging procedure.In particular the wide class of Shchrodinger operators on the graph is described by using of semigropus averaging procedure. The equivalence of presentation of quantum dynamics by unitary semigroup and by pseudomeasure on the space of trajectories of classical system is proved. The properties of averaging of random measures and random pseudomeasures (in particular, the linear and non-linear functionals on the space of measures and pseudomeasures) are studied.Note: Research direction:Mathematical modelling in actual problems of science and technic