This article describes a theoretical study of non-linear fracture behavior of the Double Cantilever Beam (DCB) configuration. The fracture is analyzed using the J-integral approach. A stress-strain curve with power-law hardening is used for describing the mechanical response of the DCB. It is assumed that the material has the same properties in tension and compression. A model based on Mechanics of materials is applied to find solutions of the J-integral at different levels of the external load. The effect of the exponent of the power law on the non-linear fracture behavior is evaluated. It is found that if higher values of the exponent of the power law are used, the J-integral value increases. The analytical approach developed here is very useful for parametric investigations, since it captures by relatively simple formulae the essential of the non-linear fracture. and Obsahuje seznam literatury
Let $\Cal P$ be an arbitrary parabolic subalgebra of a simple associative $F$-algebra. The ideals of $\Cal P$ are determined completely; Each ideal of $\Cal P$ is shown to be generated by one element; Every non-linear invertible map on $\Cal P$ that preserves ideals is described in an explicit formula.
In the paper, conditions are obtained, in terms of coefficient functions, which are necessary as well as sufficient for non-oscillation/oscillation of all solutions of self-adjoint linear homogeneous equations of the form ∆(pn−1∆yn−1) + qyn = 0, n ≥ 1, where q is a constant. Sufficient conditions, in terms of coefficient functions, are obtained for non-oscillation of all solutions of nonlinear non-homogeneous equations of the type ∆(pn−1∆yn−1) + qng(yn) = fn−1, n ≥ 1, where, unlike earlier works, fn > 0 or 6 0 (but 6≡ 0) for large n. Further, these results are used to obtain sufficient conditions for non-oscillation of all solutions of forced linear third order difference equations of the form yn+2 + anyn+1 + bnyn + cnyn−1 = gn−1, n ≥ 1.
We propose two methods to solve multistage stochastic programs when only a (large) finite set of scenarios is available. The usual scenario tree construction to represent non-anticipativity constraints is replaced by alternative discretization schemes coming from non-parametric estimation ideas. In the first method, a penalty term is added to the objective so as to enforce the closeness between decision variables and the Nadaraya-Watson estimation of their conditional expectation. A numerical application of this approach on an hydro-power plant management problem is developed. The second method exploits the interpretation of kernel estimators as a sum of basis functions.
In the paper, an attempt to interpret the PSInSAR data for the northern part of the Upper Silesian Coal Basin with the use o f kernel approximation is described. The PSI nSAR technique is characterised by the Permanent Scatterer points (so-called PS points, Permanent Scatterers), which usually correspond to the objects such as : buildings, industrial and transport infrastructure, and natural components of surface relief (Ferretti et. al., 2000, 2001). The PSInSAR technique allows to monitor ground movements. A non-uniform di stribution of the PS points makes the inte rpretation of PSInSAR data difficult, as well as the fact that one point can assume both positive an d negative values. The application of the kernel approximation for the interpretation of the PSInSAR data allowed of more unambiguous interpretation., Katarzyna Mirek and Janusz Mirek., and Obsahuje bibliografické odkazy
Paper is concerned with the flexural vibrations of imperfect bladed circular disk by analytical and numerical solutions. Dsk imperfection results from additional two groups of damping heads fixed on opposite ends of one diameter, which introduces point imperfections in mass, stiffness and nonlinear damping and non-proportional distribution of damping properties. The aim of this study is to investigate influence of friction damping among added bladed heads on decrease of resonance amplitudes. Examples based on application of equivalent linearized damping show the properties of such dampers. and Obsahuje seznam literatury
The review deals with thermal dissipation of absorbed excitation energy within pigment-protein complexes of thylakoid membranes in higher plants. We focus on the de-excitation regulatory processes within photosystem 2 (PS2) that can be monitored as non-photochemical quenching of chlorophyll (Chl) a fluorescence consisting of three components known as energy-dependent quenching (qE), state-transition quenching (qT), and photoinhibitory quenching (qI). We summarize the role of thylakoid lumen pH, xanthophylls, and PS2 proteins in qE mechanism. Further, both the similarity between qE and qI and specific features of qI are described. The other routes of thermal energy dissipation are also mentioned, that is dissipation within photosystem 1 and dissipation through the triplet Chl pathway. The significance of the individual de-excitation processes in protection against photo-oxidative damage to the photosynthetic apparatus under excess photon supply is stretched. and M. Štroch, V. Špunda, I. Kurasová.
We shall introduce the class of strongly cancellative multiplicative monoids which contains the class of all totally ordered cancellative monoids and it is contained in the class of all cancellative monoids. If G is a strongly cancellative monoid such that hG ⊆ Gh for each h ∈ G and if R is a ring such that aR ⊆ Ra for each a ∈ R, then the class of all non-singular left R-modules is a cover class if and only if the class of all non-singular left RG-modules is a cover class. These two conditions are also equivalent whenever we replace the strongly cancellative monoid G by the totally ordered cancellative monoid or by the totally ordered group.