a new approach is proposed to model a crack in orthotropic composite media using the extended finite element method (xfem). the xfem uses the concept of partition of unity in addition to meshless basic idea of approximating a field variable by its values at a set of surrounding nodes. as a result, higher order approximations can be designed with the same total number of degrees of freedom. in t...

The effect of the tip gap size on the performance of a multistage axial compressor was studied by means of computational fluid dynamics (CFD). It was found that the performance of the compressor was very sensitive to the size of the tip gap. By increasing the gap size, the stall margin value, the total pressure ratio and the compressor efficiency reduced considerably. The flow field at the tip ...

Spectroscopic methods with high spatial resolution are essential for understanding the physical and chemical properties of nanoscale materials, including quantum structures and biological surfaces. An optical technique is reviewed that relies on the enhanced electric fields in the proximity of a sharp, laser-irradiated metal tip. These fields are utilized for spatially confined probing of vario...

Apertureless magneto-optical near-field microscopy is developed for studying subpicosecond spindynamics at nanometer spatial scale. Polarization modulation and tip vibrations are implemented. Polarization responsivity of the tip-induced scattering is demonstrated using polarization modulation and tip vibrations. A near-field magneto-optical contrast is achieved for a thin ferromagnetic film wit...

We present measurements and calculations of the terahertz (THz) electric field measured in the near field of a metal tip used in THz apertureless near-field optical microscopy (THz-ANSOM). An analytical model in which we treat the metal tip as a linear wire antenna allows us to predict almost all of the features observed in the measurements, such as the relatively slow decay of the near-field a...

Reliability of gas turbine power plant is related to the blade normal operation. In this paper, a new on-line condition monitoring method has been presented to evaluate two important factors affecting the turbine blades that are the tip clearance and tip deformation. A K band’s microwave sensor has been simulated and optimized in CST Microwave Studio software. Scattering parameters of the near...