Development of a novel shrouded impeller pediatric blood pump.

The aim of this work was to analyze a shrouded impeller pediatric ventricular assist device (SIP-VAD). This device has distinctive design characteristics and parameter optimizations for minimization of recirculation flow and reduction in high-stress regions that cause blood damage. Computational Fluid Dynamics (CFD) simulations were performed to analyze the optimized design. The bench-top prototype of SIP-VAD was manufactured with biocompatible stainless steel. A study on the hydrodynamic and hemodynamic performance of the SIP-VAD was conducted with predictions from CFD and actual experimentation values, and these results were compared. The CFD analysis yielded a pressure range of 29-90 mmHg corresponding to flow rates of 0.5-3 L/min over 9000-11000 rpm. The predicted value of the normalized index of hemolysis (NIH) was 0.0048 g/100 L. The experimental results with the bench-top prototype showed a pressure rise of 30-105 mmHg for the flow speed of 8000-12000 rpm and flow rate of 0.5-3.5 L/min. The maximum difference between CFD and experimental results was 4 mmHg pressure. In addition, the blood test showed the average NIH level of 0.00674 g/100 L. The results show the feasibility of shrouded impeller design of axial-flow pump for manufacturing the prototype for further animal trials.

Multi-Stressed Nano and Micro-Silica/Silicone Rubber Composites with Improved Dielectric and High-Voltage Insulation Properties.

The scope of silicone rubber (SiR) is confined due to the deprivation of its dielectric propertiesupon exposure to various ambient stresses. The aim of this research is to develop silicone rubber-based composites by employing inorganic oxide fillers for improved dielectric and high voltage insulation properties for widening its scope in the field of electrical appliances. This study reports the preparation of different composites of silicone rubber with varying concentrations of micro and nano-silica fillers. The dielectric propertytrends of these as-prepared neat and impregnated samples were examined via an indigenously developed weathering chamber capable of applying multiple stresses of acid rain, heat, humidity, UVA radiation, and salt fog. Dielectric constant values were measured before and after applying stresses. Upon applying stresses, a periodic decline in dielectric constant was observed. Improved dielectric properties were obtained by adding micro and nano-silica as fillers. A nano silica-incorporated silicone rubber product exhibited good potential for dual applications as dielectric and high voltage insulation.