Fracture toughness (K1C) of medium carbon steel (0.5% C) has been determined by round notched tensile specimen. Two notch diameters (5.6mm and 4.2mm) and three notch angles (α) namely 45, 60 and 75 have been used to observe the effect of notch diameters and notch angle on fracture toughness of the steel. By heat treatment the microstructure of the steel is also varied and its effect on the frac...

The toughness of a (non-complete) graph G is the minimum value of t for which there is a vertex cut A whose removal yields |A|/t components. Determining toughness is an NP-hard problem for general input graphs. The toughness conjecture of Chvátal, which states that there exists a constant t such that every graph on at least 3 vertices with toughness at least t is hamiltonian, is still open for ...

Mental toughness in endurance athletes, while an important factor for success, has been scarcely studied. An online survey was used to examine eight mental toughness factors in endurance athletes. The study aim was to determine mental toughness profiles via latent profile analysis in endurance athletes and whether associations exist between the latent profiles and demographics and sports charac...

Seed size and toughness affect seed predators, and size-dependent investment in mechanical defence could affect relationships between seed size and predation. We tested how seed toughness and mechanical defence traits (tissue density and protective tissue content) are related to seed size among tropical forest species. Absolute toughness increased with seed size. However, smaller seeds had high...

this article aims to review various modes of fracture toughness of resin composites. also, this study intends to review the papers on the fracture mode, namely “fractography”, under scanning electron microscopy finding fracture initiation site, and the effect of filler content on the fracture toughness of resin composites. it will also review the effect of aging on the fracture toughness of res...

The authors conducted an investigation of mental toughness in a sample population of athletes who have achieved ultimate sporting success. Eight Olympic or world champions, 3 coaches, and 4 sport psychologists agreed to participate. Qualitative methods addressed 3 fundamental issues: the definition of mental toughness, the identification of its essential attributes, and the development of a fra...

We show that, if NP 6= ZPP, for any ε > 0, the toughness of a graph with n vertices is not approximable in polynomial time within a factor of 1 2 (n 2 ). We give a 4-approximation for graphs with toughness bounded by 1 3 and we show that this result cannot be generalized to graphs with a bounded toughness. More exactly we prove that there is no constant approximation for graphs with bounded tou...

Recently, a method for evaluating the fracture toughness of ceramics has been proposed by Fett based on the computed crack-opening displacements of cracks emanating from Vickers hardness indentations. To verify this method, experiments have been conducted to determine the toughness of a commercial silicon carbide ceramic, Hexoloy SA, by measuring the crack-opening profiles of such Vickers inden...

A heterogeneous brittle material characterized by a random field of local toughness K c (x) can be represented by an equivalent homogeneous medium of toughness, K eff. Homogenization refers to a process of estimating K eff from the local field K c (x). An approach based on a perturbative expansion of the stress intensity factor along a rough crack front shows the occurrence of different regimes...

The concept of mental toughness is widely used, but empirical evidence is required to fully understand this construct and its related variables. The purpose of this paper was to explore the relationship between: (a) mental toughness and coping, (b) mental toughness and optimism, and (c) coping and optimism. Participants were 677 athletes (male 454; female 223) aged between 15 and 58 years (M ag...