We characterise the aperiodic autocorrelation for a Boolean function, f , and define the Aperiodic Propagation Criteria (APC) of degree l and order q. We establish the strong similarity between APC and the Extended Propagation Criteria (EPC) as defined by Preneel et al. in 1991, although the criteria are not identical. We also show how aperiodic autocorrelation can be related to the first deriv...

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...

Peridynamics (PD) is a nonlocal continuum theory based on integro-differential equations without spatial derivatives. The elongation fracture criterion is implicitly incorporated in the PD theory, and fracture is a natural outcome of the simulation. On the other hand, a new fracture criterion based on the crack opening displacement combined with peridynamic (PD-COD) is proposed. When the relati...

because of high strength to weight ratio, 6061 aluminum has many applications in different industries like automotive and aerospace industries and can help to reduction of fuel consumption. forming limit diagram (fld) is a useful method for sheet metal formability identification. whereas calculation of forming limit diagram by experimental tests is expensive and time consumption, in the present...

in this work, the mechanism for fracture of brittle substances such as rocks under a uniform normal tension is considered. the oriented straight micro-cracks are mostly created in all the polycrystalline materials resulting from the stress concentrations. the present work focuses on the interactions of the pre-existing micro-cracks, which can grow and propagate within a rock-like specimen. the ...

Mahu oilfield is a typical tight gravel oil reservoir. At present, long-stage multi-cluster fracturing widely used for reservoir stimulation, and multiple-clusters treatment realized through cluster perforation. Field monitoring indicates that not all perforation clusters produce hydraulic fractures in the process, each of section will expand unevenly. The unbalanced expansion multiple seriousl...

Background and objective: Open tibial fracture with or without bone loss in gustilo Anderson type IIIA and IIIB has been a challenge for most orthopaedic surgeons. Open tibial fracture is more prone for infection, non union and longer morbidity. In this study, we have evaluated the results of 34 patients with open tibial fracture GA type IIIA and IIIB by Ilizarov method in retrospective manner....