Materials Engineering

The aim of the study was to improve the efficiency of the double roller cotton gin in terms of ginning output and energy consumption. Therefore a spike cylinder–type gin feeder with the concept of single locking of cotton bolls was developed and optimized. The speed of the spike cylinder of the single locking feeder and cotton moisture were optimized using response surface methodology for long and medium staple cotton. Ginning output of the double roller gin was maximized and the specific energy requirement for ginning was minimized during optimization. Quadratic models were fitted for prediction of ginning output and specific energy. Optimum cotton moisture of 7.38 and 7.15% and optimum spike cylinder speed of 307 and 297 rpm with desirability of 0.9185 and 0.8923 were arrived at using multiple regression analysis for long and medium staple cotton, respectively. Use of the single locking cotton feeder for long and medium staple cotton resulted in a 22 and 25% increase in ginning ou...

Stay-in-place (SIP) formwork is a more-practical alternative to traditional steel or wood formworks due to its improved constructability and durability. The aim of this paper was to study the fire resistance performances of structural and non-structural concrete panels with polyvinyl chloride (PVC) SIP formwork. Three 124.01 in × 110.24 in × 3.15 in panels of PVC SIP formwork were tested and compared to one another. All panels were aged for 28 days, then exposed to the standard fire curve based on the ISO 834:2014 standard, and the temperatures in each panel surface recorded. The results indicate that concrete strength significantly influenced the structural stability and the fire resistance time of the panels (under load), even in this type of panels when exposed to high temperatures. It was found that the PVC encasement enhanced the thermal insulation property, one of the fire resistance performance criteria. Overall, the importance of this alternative formwork is the reduction in the use of forest resources, the raise of awareness of their conservation, and the promotion of their rational use as this a material is friendly to the environment.