Iris-based human identity recognition with machine learning methods and discrete fast Fourier transform

Innovations in Systems and Software Engineering - One of the most important modules of computer systems is the one that is responsible for user safety. It was proven that simple passwords and...     

Correlation between the fracture roughness and fatigue threshold of high-temperature degraded steel

We analyze the influence of degradation of 12Kh1MF heat-resistant steel under in-service and laboratory conditions on the characteristics of surface roughness after fatigue fracture. It is shown that the behavior of the threshold stress intensity factor ΔK _{th cl} characterizing the effect of crack closure is similar to the behavior of the amplitude characteristics of surface roughness in the direction perpendicular to the direction of crack propagation. This enables to make a conclusion that the decisive role in the process of crack closure in the degraded metal is played by longitudinal shear. It is shown that hydrogen absorbed by the degraded metal determines the characteristics of its crack resistance and affects the process of crack closure. We propose a model of crack closure that additionally takes into account the influence of longitudinal shear. Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv; Technical University of Wrocław, Poland. Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 35, No. 6, pp. 37–42, November–December, 1999.