Background: The study is intended to examine a model of direct and indirect effects (through mediating role of self-assessment latent variable containing self-efficacy and self-esteem components) of sports mental toughness construct (including the components of confidence, consistency and control) on perceived stress of athlete employees. Method: The rese...

ÐCommercially available alumina of 94% nominal purity was used to examine the in ̄uence of loading rate on toughening mechanisms. For ®ne-grained alumina, the crack resistance, KR, was found to be independent of crack length and loading rate. Coarse-grained alumina exhibited strongly rising R-curves where the initial fracture toughness, K0, was found to be independent of the loading rate. The ne...

Cross-linked polymer networks are widely used as structural and protective materials, which require strength and toughness. Experiments have shown that cross-linked poly(dicyclopentadiene) (pDCPD) networks provide similar strength but superior fracture toughness relative to commonly-used network chemistries like epoxy. To better understand pDCPD, we use atomistic molecular dynamics to study the...

Systematic studies of alloys based on TiCr, have been performed in order to impro Ttoughness of Laves phase intermetallics. The extent to which alloy compositions and annealing treatments influence the toughness was quantified by Vickers indentation. The single-phase Laves behavior was first established by studying stoichiometric and nonstoichiometric TiCr,. Next, alloying effects were investig...

Mineralized biological materials such as bone, sea sponges or diatoms provide load-bearing and armor functions and universally feature structural hierarchies from nano to macro. Here we report a systematic investigation of the effect of hierarchical structures on toughness and defect-tolerance based on a single and mechanically inferior brittle base material, silica, using a bottom-up approach ...

Combinations of high strength and ductility are hard to attain in metals. Exceptions include materials exhibiting twinning-induced plasticity. To understand how the strength-ductility trade-off can be defeated, we apply in situ, and aberration-corrected scanning, transmission electron microscopy to examine deformation mechanisms in the medium-entropy alloy CrCoNi that exhibits one of the highes...

Bioactive glass (BG) is widely used for bone tissue engineering. However, poor mechanical properties are the major shortcomings. In the study, hydroxyapatite nanowhisker (HANw) was used as a reinforcement to improve the mechanical properties. 63s glass/HANw scaffolds were successfully fabricated by selective laser sintering (SLS). It was found that the optimal compressive strength and fracture ...

Aging and bone diseases are associated with increased fracture risk. It is therefore pertinent to seek an understanding of the origins of such disease-related deterioration in bone's mechanical properties. The mechanical integrity of bone derives from its hierarchical structure, which in healthy tissue is able to resist complex physiological loading patterns and tolerate damage. Indeed, the mec...

The effect of the degree crystallinity on fracture toughness titanium–PEKK interfaces was investigated experimentally. level at interface varied by employing different processes commonly used in aerospace, namely autoclave consolidation, press-forming and annealing. assessed via Double Cantilever Beam test, while polymer evaluated Differential Scanning Calorimetry. Fracture surfaces were analyz...

Hardfacing alloys are weld deposited to provide a wear resistant surface for stmctural base materials. Commercial low cobalt hardfacing alloys are being evaluated to reduce plant activation levels. Since hardfacing alloys typically must be resistant to cracking to assure adequate in service performance, fracture toughness is a ~ critical material property. Fracture toughness (KJ measurements of...