Zirconia-nickel functionally graded materials were obtained by powder metallurgy technique. The microstructure, residual stress, fracture toughness and Vickers hardness were investigated. Mixed-mode fracture response of YSZ /Ni functionally graded materials was examined utilizing the three point bending test and finite element method (Cosmos/M 2.7). The results show that the stress intensity fac...

this paper presents some analyses about the robust practical stability of a class of nonlinear affine systems in the presence of non-vanishing perturbations based on the passivity concept. the given analyses confirm the robust passivity property of the perturbed nonlinear systems in a certain region. moreover, robust control laws are designed to guarantee the practical stability of the perturbe...

We study the effect of spiral arm passages on the evolution of star clusters on planar and circular orbits around the centres of galaxies. Individual passages with different relative velocity (Vdrift) and arm width are studied using N -body simulations. When the ratio of the time it takes the cluster to cross the density wave to the crossing time of stars in the cluster is much smaller than one...

Evidence from both human and animal studies suggests that sensitivity to rewarding stimuli is positively associated with impulsive behaviors, including both impulsive decision making and inhibitory control. The current study examined associations between the hedonic value of a sweet taste and two forms of impulsivity (impulsive choice and impulsive action) in healthy young adults (N = 100). Par...

Introduction: To investigate the effects of predictable and unpredictable external perturbations on cortical activity in healthy young and older adults. Methods: Twenty healthy older and 19 healthy young adults were exposed to predictable and unpredictable external perturbations, and their cortical activity upon postural recovery was measured using a 32-channel quantitative encephalography. Th...

Impulsive and convective frequencies are one of the most important subjects for evaluation of the seismic behavior of tanks. These two frequencies are defined by Housner and used for obtaining Rayleigh damping in time history analysis. ACI 350 and NZSEE standards have suggested some analytical solutions for finding convective and impulsive frequencies. These frequencies can also extract from mo...

One of primary reasons for the establishment of the ARM Southern Great Plains research site was to obtain long-term records of surface radiation data and the impact of clouds on these data (Stokes and Schwartz 1994). This research project focuses on the creation of a two-year climatology of the surface radiation budget and the impact of clouds on that budget. The period of analysis extends from...

Thermal and dynamic perturbations in the polar upper stratospheric/mesosphere-lower thermosphere Arctic winter of 2019–2020 as measured by a meteor radar at 67°N, Aura Microwave Limb Sounder reanalysis are presented. The most severe disturbances occur from late December to mid-January, while rest is relatively stable. Mesospheric winds dominated several impulsive increases zonal component, an a...

This paper identifies and analyzes stable sun-synchronous orbits in aHill rotating frame that can be applied to any small body in the solar system. The stability of these orbits is due to the inclusion of solar radiation pressure effects. The stability of the orbits from escaping the comet are analyzed using the construction of zero-velocity curves for the system considered as well as spectral ...