Quite often practical problems of optimal design have no solution. This situation can be alleviated by relaxation, where one needs generalised materials which can mathematically be defined by using the theory of homogenisation. First mathematical results in this direction for general (nonperiodic) materials were obtained by Murat and Tartar. We present some results in optimal design where the e...

The rheological properties of soft materials often exhibit surprisingly universal linear and nonlinear features. Here we show that these properties can be unified by considering the effect of the strain-rate amplitude on the structural relaxation of the material. We present a new form of oscillatory rheology, strain-rate frequency superposition (SRFS), where the strain-rate amplitude is fixed a...

In the context of strain-energy-deployed space structures, material relaxation effects play a significant role in structures that are stowed for long durations, for example, in a space vehicle prior to launch. Here, the deployment of an ultrathin carbon fiber reinforced plastic (CFRP) tape spring is studied, with the aim of understanding how longduration stowage affects its deployment behavior....

We study the coarsening of strongly microphase separated membrane domains in the presence of recycling of material. We study the dynamics of the domain size distribution under both scalefree and size-dependent recycling. Closed form solutions to the steady state distributions and its associated central moments are obtained in both cases. Moreover, for the size-independent case, the time evoluti...

The formation of dislocation-free three-dimensional islands during the heteroepitaxial growth of lattice-mismatched materials has been observed experimentally for several material systems. The equilibrium shape of the islands is governed by the competition between the surface energy and the elastic relaxation energy of the islands as compared to the uniform strained film. As an exemplification ...

A statistical mechanical approach to granular material is proposed. Using lattice models from standard Statistical Mechanics and results from a mean field replica approach we find a jamming transition in granular media closely related to the glass transition in super-cooled liquids. These models reproduce the logarithmic relaxation in granular compaction and reversible-irreversible lines, in ag...

Silicon, the main material of microelectronics, is predominantly composed of nuclei with zero spin and is characterised by weak spin-orbit interaction in the conduction band. This insures long distance spin propagation through the bulk, which in combination with a possibility of injecting spin at room temperature [2] makes fabrication of spin-based switching devices in the near future feasible....

Owing to lack of time translational invariance, aging soft glassy materials do not obey fundamental principles of linear viscoelasticity. We show that by transforming the linear viscoelastic framework from a real time domain into an effective time domain, wherein the material clock is readjusted to account for evolution of relaxation time, the soft glassy materials obey effective time translati...

Ultrafast spin dynamics in ferromagnetic half-metallic compound Sr 2 FeMoO 6 is investigated by pump-probe measurements of magneto-optical Kerr effect. Anomalous thermal insulation between spins and electrons due to half-metallic nature of this material gives rise to a very slow spin relaxation from a few to several-hundred picosecond after the optical excitation. The optically detected magneti...

Doping Ni80Fe20 by heavy rare earth atoms alters the magnetic relaxation properties of this material drastically. We show that this effect can be well explained by the slow relaxing impurity mechanism. This process is a consequence of the anisotropy of the on site exchange interaction between the 4f magnetic moments and the conduction band. As expected from this model the magnitude of the dampi...