Optimum Sustainable Mix Proportions of High Strength Concrete by Using Taguchi Method

In this study, mix proportion parameters of high strength concrete (HSC) were analyzed by using the Taguchi’s experiment design methodology for optimal design. For that purpose, mixtures are designed in a L27 orthogonal array with six factors, namely, ‘Silica Fume’, ‘Steel Fiber’, ‘Super-Plasticizer’, ‘Maximum Aggregate Size (AG)’, ‘Water / cementitious material (W/C) ratio’, ‘Fly Ash’. The mixtures were extensively tested to meet technical requirements of HSC. The experimental results were analyzed by using the Taguchi experimental design methodology. The best possible levels for mix proportions were determined for maximization of compressive strength at 7, 28, 56, 90 days, splitting tensile strength at 28 days, flexural strength at 28 days, and the slump. Also the best possible levels for mix proportions were determined for minimization of the production cost. It was found that steel fibers and fly ash are the most dominant factors in the process of optimization. The advantage of using steel fiber and fly ash was the reduced energy and cost associated with the raw materials which meant more sustainable concrete could be attained. It was also found that there is a necessity to apply a multi- response optimization to get the best mix proportions

The Cardioprotective Effect Of Selenium In Myocardial Ischemia Reperfusion Injury

The objective of the current study is to assess the possible cardioprote-ctive effect of selenium in myocardial ischemia reperfusion injury induced by ligation of coronary artery in a male rat model. 24 adult male spraguedawley rats were randomized into 4 equal groups: (1), Sham group, rats underwent the same anesthetic and surgical procedures as the control group except for LAD ligation; (2), Active control group, rats subjected to regional ischemia for 30 min by ligation of LAD coronary artery and reperfusion for 2 hours; (3), Control vehicle group, rats received D.W (vehicle of selenium) via IP route and subjected to ischemia for 30 minutes before ligation of LAD coronary artery & reperfusion for 2 hr; (4), Seleniumtreated group, rats pretreated with selenium5mg/kg via IP injection 30minutes before ligation of  LAD coronary artery & then subjected to reperfusion for 2 hr. In control group, as compared with sham, tissue TNF-α, IL-6, IL-10, caspase-3 and BAX, plasma cTn-T and serum MDA significantly increased (P<0.05), while serum GSH significantly decreased (P<0.05). Histopathologically, control group showed a significant cardiac injury (P<0.05) compared with sham group. Selenium significantly counteracted (P<0.05) the increase of TNF-α, IL-6, caspase-3 and BAX and counteracted the increase in plasma cTn-T and serum MDA. Selenium produces a significant elevation (P<0.05) in cardiac IL-10 and serum GSH with significant reduction in (P<0.05) cardiac injury. In Conclusions, Selenium minimizes myocardial I/R injury in male rats via interfering with inflammatory reactions and apoptosis which were induced by I/R injury