Viscoelastic Effects on Intralaminar Fracture Toughness of Epoxy/Carbon-fibre Laminates

The Double Torsion technique has been applied to characterize the fracture resistance of a unidirectional an a woven epoxy/ carbon-fire composite material. The crack speed has been varied by about four orders of magnitude for testing temperatures ranging form below the glass transition of the rubber modifier of the epoxy matrix to the glass transition of the matrix itself. A noteworthy variation was found in the fracture toughness and surface morphology of the unidirectional composite. Decreasing fracture toughness values were observed by increasing crack speed at 23 °C, which is somewhat unusual for viscoelastic materials. Results have been discussed in the framework of viscoelastic fracture mechanics, and the fracture behavior at different rates and temperatures has been shown to be related to different viscoelastic mechanisms

Total hip arthroplasties in young patients under 50 years: limited evidence for current trends. A descriptive literature review

Item does not contain fulltextWe examined all reported outcomes of uncemented and cemented total hip arthroplasty in patients younger than 50 years of age listed in Medline (1966- 1 January 2009) and PubMed, and scrutinised reference lists of relevant papers. In addition, we evaluated relevant data in the Swedish hip arthroplasty register. 109 relevant articles were identified, 37 of which had a mean follow-up longer than 10 years. Although uncemented implants are widely used in patients under 50 years of age, there are only 2 reports that fulfil the criteria published by the National Institute for Clinical Excellence (NICE) in the United Kingdom (follow-up of >10 yrs and survival of =90%). Current trends relating to implant selection remain unsupported by survival data, and additional information about the long-term results of newer implants is essential. As matters stand, the most reliable results relate to cemented implants