In the framework of crack number density analysis, a theoretical investigation is carried out on the relationship between the statistical characteristics of fatigue initiation life and the stochastic growth of short fatigue cracks. The numerical results indicate that, compared with the influence of grain boundary resistance, the effect of the degree of randomness of crystallographic crack growt...

An evaluation of the fatigue crack resistance of human dentin was conducted to identify the degree of degradation that arises with aging and the dependency on tubule orientation. Fatigue crack growth was achieved in specimens of coronal dentin through application of Mode I cyclic loading and over clinically relevant lengths (0 ≤ a ≤ 2 mm). The study considered two directions of cyclic crack gro...

In this paper the TMF crack initiation behaviour of the single-crystal nickel-base superalloy MD2 is investigated and modelled. TMF tests were performed in both IP and OP for varying mechanical strain ranges in the [001] crystallographic direction until TMF crack initiation was obtained. A crystal plasticity-creep model was used in conjunction with a critical-plane approach, to evaluate the num...

OBJECTIVE The purpose of this study was to evaluate the extent to which demographic, sexual, and non-injection drug use practices predict adolescent initiation of injection drug use. METHODS Street recruited injection drug users 15-30 years of age in Baltimore, Maryland, who initiated injection within five years of study enrollment, completed a questionnaire that included a year-by-year histo...