Three-dimensional deformation field in the vicinity of a blunt crack in a sheet of low-hardening material is determined using laser speckle and moir6 techniques. Experimental results are compared with the HRR singularity field. A zone of dominant three-dimensional effects is mapped out ahead of the crack tip. Strain contours, elastic plastic boundary and maximum shear strain trajectories are al...

In this paper altitude measurement from water surface using laser beam is presented. Research data indicate that the reflection of infrared waves from water surface is about zero and it is less than 2% for visible radiations. Phase-shift and heterodyne technique was used for the measurement, and the laser beam ( mW p nm 10 , 700 = = l ) was modulated by a sine wave having a fixed frequency....

Hardening plasticity has a long history in constitutive modelling, with many applications in geomechanics. Mathematical models of non-hardening plasticity involve the definition of a single stationary yield surface in stress-space. Examples include the conventional models of elasto-plasticity, often based on the yield criteria of Tresca, von Mises, and Mohr-Coulomb. Within the yield surface the...

The influence of rheological and surface properties on adhesive tackiness are studied. In particular, the importance of the elongational properties is emphasized in a model, which considers only the adhesive contribution, while neglecting the importance of cavitation and surface roughness. It is shown that this simple analysis allows one to recover the different types of curves (i.e. different ...

A study of surface hardening Ductile Iron (DI) with and without austempering heat treatment was developed. The chemical composition the material contains alloying elements such as Cu Ni, that allow to obtain a Grade 120-90-02, based on ASTM A536, which treated be transformed Austempered (ADI). Specimens 10 × 5 mm3 were obtained for application by Nd:YAG UR laser 150 W maximum power. parameters ...

We investigate the transient viscoelastic response of weakly strain-hardening fluids to imposed elongational deformation in filament stretching devices. We combine timedependent finite-element simulations with quantitative experimental measurements on a rheologically well-characterized test fluid to investigate how well the device reproduces the ideal transient uniaxial extensional viscosity pr...

Microstructural changes during laser welding and laser surface treatment has been regarded by many researchers. Most researches have focused on studying the effect of various process parameters on the size and microstructure of the heat affected zone. But some studies show that the initial microstructure of the base metal can also affect the heat affected zone dimensions and final microstructur...

The influence of Na on Cu(In,Ga)Se2 (CIGS) solar cells was investigated. A gradient profile of the Na in the CIGS absorber layer can induce an electric field modulation and significantly strengthen the back surface field effect. This field modulation originates from a grain growth model introduced by a combination of alloy-hardening and pair-annihilation probabilities, wherein the Cu supply and...

Laser Phototherapy (LPT) is an effective tool to stimulate bone. A series of promising protocols developed by our group are presented. Our results show that the use of IR laser results on increased bone neorformation. LPT effect depends not only on the total dose, but also on both irradiation time and mode. Energy density and intensity are biologically independent and accounts for the success a...