In this paper, failure mechanism of a 17th stage blade of an 82.5 MW steam turbine that caused damage to the internal turbine compartment and the adjacent blade equipment has been studied. In order to determine the cause of failure and prevent similar events, various metallurgical and mechanical investigations including chemical composition analysis, metallography and microstructural analysis, ...

We investigate the design, fabrication and experimental characterization of high Quality factor photonic crystal nanobeam cavities in silicon. Using a five-hole tapered 1D photonic crystal mirror and precise control of the cavity length, we designed cavities with theoretical Quality factors as high as 1.4 × 10. By detecting the cross-polarized resonantly scattered light from a normally incident...

Abstract: Perovskite solar cells have become an attractive subject in the solar energydevice area. During ten years of development, the energy conversion efficiency has beenimproved from 2.2% to more than 22%, and it still has a very good potential for furtherenhancement. In this paper, a numerical model of the perovskite solar cell with thestructure of glass/ FTO/ TiO2/...

OBJECTIVE Both state and federal regulations require weekly monitoring of the resolution and linearity of the scintillation camera. Several phantoms are available to perform this quality control function. These include the quadrant bar. Bureau of Radiological Health (BRH), and orthogonal-hole (OH) phantoms. Each of these phantoms has either functional or temporal limitations on its use. The ort...

PURPOSE This work is a preliminary study of a stationary cardiac SPECT system. The goal of this research is to propose a stationary cardiac SPECT system using segmented slant-hole collimators and to perform computer simulations to test the feasibility. Compared to the rotational SPECT, a stationary system has a benefit of acquiring temporally consistent projections. The most challenging issue i...

In this paper, we calculate electron and hole impactionization coefficients in In0.52Al0.48As using a Monte Carlo modelwhich has two valleys and two bands for electrons and holesrespectively. Also, we calculate multiplication factor for electronand hole initiated multiplication regimes and breakdown voltagein In0.52Al0.48As PIN avalanche photodiodes. To validate themodel, we compare our simulat...

astrophysics is becoming now an integral part of general physics. considering the black hole theory ,which is a new and exciting branch of relativistic astrophysics, we see many connections between elementary particle physics and astrophysics. in this article we attempt to explain the development of star physics ,in an easy ,understandable manner. previous knowledge of relativistic theory or cl...

The use of blasting cost (BC) prediction to achieve optimal fragmentation is necessary in order to control the adverse consequences of blasting such as fly rock, ground vibration, and air blast in open-pit mines. In this research work, BC is predicted through collecting 146 blasting data from six limestone mines in Iran using the artificial neural networks (ANNs), gene expression programming (G...

In 3DTV research, virtual view synthesis is a key component to the technology. Depth-image-based-rendering (DIBR) is an important method to realize virtual view synthesis. However, DIBR always results in hole problems where the depth and colour values are not known. Hole-filling methods often cause other problems, such as edge-ghosting and cracks. This paper proposes an algorithm that uses the ...

OBJECTIVE To investigate the sleep state of mild stroke patients and relationship between sleep disturbance and functional status. METHODS A total of 80 acute stroke patients were enrolled in this study. The criteria for inclusion in the study was as following: 1) first stroke, 2) cognitive function preserved enough to perform the test (Mini Mental State Examination ≥24), 3) good functional l...