Strain hardening behavior of lightweight hybrid polyvinyl alcohol (PVA) fiber reinforced cement composites

Experimental results on the strain hardening and multiple cracking behaviors of polyvinyl alcohol (PVA) fiber reinforced cementitious composites under bending are reported in this paper. Different hybrid combinations of PVA fibers with different lengths and volume fractions are considered to reinforce the mortar matrix. Among different hybrid combinations, the composite containing 2% thicker PVA fibers of 12 mm length and 1% thinner PVA fibers of 6 mm length and the composite containing 2% thicker PVA fibers of 24 mm length and 1% thinner PVA fibers of 6 mm length showed the best performance in terms of highest ultimate load, largest CMOD (crack mouth opening displacement) at peak load and multiple cracking behavior. The effects of four types of light weight sands on the strain hardening and multiple cracking behavior of hybrid fiber composites are also evaluated in this study. It has been observed that the ultimate load and CMOD at peak load for all light weight hybrid fiber composites are almost the same irrespective of volume fractions of light weight sand. The composites containing finer light weight sands exhibited higher ultimate load than those containing coarser light weight sands. It is also observed that the hybrid fiber composite containing normal silica sand exhibited higher ultimate load than the composites with light weight sands

Gastrointestinal Stromal Tumours treated before and after the advent of c-kit immunostaining

<p>Abstract</p> <p>Background</p> <p>Recently developed immunohistochemical markers have revolutionised the classification of gastrointestinal stromal tumours (GISTs) whilst tyrosine kinase inhibitors (imatinib) have had a significant impact on the treatment of advanced tumours. We review the clinicopathological features of previously resected mesenchymal tumours of the gastrointestinal tract in our institution to 1) reclassify the histological diagnosis of those stained prior to c-kit availability; 2) perform survival analysis to identify prognostic factors, and 3) to consider the implications for patients.</p> <p>Methods</p> <p>Clinicopathological records of patients with a diagnosis of mesenchymal tumours treated between May 1992 and April 2007 were reviewed.</p> <p>Results</p> <p>82 patients were reviewed. 26 (32%) were reclassified as GISTs following c-kit immunostaining and a further 14 patients were treated for GIST up to April 2007 (Total: 40 patients; 21 males and 19 females, mean age 67, range 30-92 years). 36 (90%) underwent complete resection. 5-year survival of patients with GIST alone was 80%. Females had a better median survival (M: F 43 months: 73 months).</p> <p>Conclusions</p> <p>The availability of c-kit staining allowed 32% of previously diagnosed mesenchymal tumours to be reclassified as GISTs. This may have implications for the follow-up of patients diagnosed prior to the availability of this method.</p

Creep testing methodologies and results interpretation

This paper presents a literature review on the main testing methodologies used to investigate the long-term behaviour of cracked FRC elements. Various tests methods such as pull-out tests, uniaxial tension tests, beam bending tests, and plate bending tests are illustrated and discussed. The paper originates from a round table held during the FRC-CREEP 2016 workshop