BazTech - Yadda

1

Application of shape memory alloy in harvesto-absorber system

Kęcik K.

Acta Mechanica et Automatica

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2015

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Vol. 9, no. 3

155--160

EN

This paper presents a conception of the harvester-absorber system consisting of two parts. The first is the pendulum attached to the main system (oscillator), which is suspended on the linear damper and the nonlinear spring made of shape memory alloy. The spring is modelled as a polynomial function based on Landau–Ginzburg theory of phase transitions (similar as ferroelectric and ferromagnets). The obtained results show, that SMA element can increase harvesting energy level, while the absorber effect can be impaired (but not loss). Additionally, introducing SMA element causes changes in dynamics, introduces a new unstable solutions and bifurcations. The analysis was done by classical integration and continuation solution methods.

2

Extended Ginzburg-Landau theory of magnetically active anisotropic superconductors

Rogula D.

Journal of Technical Physics

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2004

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Vol. 45, no 3

243-251

EN

A formulation of thermodynamical theory of magnetically active, anisotropic materials admitting coexistence of the superconductivity and magnetic order is proposed. The theory is based on the Ginzburg-Landau approach extended to multi-component order parameters and the states of thermodynamic quasi-equilibrium far from the superconducting phase transition. The field equations are derived under assumption of the U(1) gauge invariance. The questions of exact anisotropic similarity transformations as well as approximate anisotropic scaling are discussed.

3

Inhomogeneous superconductivity and vortices in the stripe states

Lenkowska-Czerwińska T.

Journal of Technical Physics

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2002

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Vol. 43, no 3

335-341

EN

Spatially inhomogeneous features in the spin and charge structures have been indicated in the number of experiments on high temperature materials e.g. La2-xSrxCuO4. The simple realization of this state is striped domain wall where charges form a nanoscale linear pattern in an antiferromagnetically ordered isolator. These represent a nanoscale distribution of charge and spin that is believed to be commensurably locked by the tilt distortions of the lattice. The phenomenological model of charge and spin inhomogeneities in the stripe phase of superconducting cuprates on the ground of Ginzburg-Landau theory is proposed. The corresponding free energy for the coupled charge and spin-density wave, and superconducting order parameters is constructed. The phase diagram for inhomogeneous superconducting state is discussed. The effective coherence length and the penetration depth in the London limit are introduced. The critical magnetic fields and the energy of the isolated vortex line are obtained.

4

Alternating states in layered high-T[c] superconductors

Rogula D., Lenkowska-Czerwińska T.

Journal of Technical Physics

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2001

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Vol. 42, no 2

269-274

EN

The coupling between lattice distortion modes and the superconducting order parameters for the layered, high temperature superconductors of La214 class is considered. The set of structural micro-order parameters is determined on the ground of a model of coupled quasi-rigid CuO6 octahedra. The admissible combinations of the superconducting micro-order parameter components are presented. The time reversal symmetry of microscopic and macroscopic states due to correlation between structural and superconducting order parameters is discussed.