Assessment of the Influence of Graphene Nanoparticles on Thermal Conductivity of Graphene/Water Nanofluids Using Factorial Design of Experiments

In this study, 23 factorial design of experiment was employed to evaluate the effect of parameters of hot fluid inlet temperature, graphene nanofluid concentration and hot fluid flow rate on thermal conductivity of graphene/water nanofluid. The levels of  hot fluid inlet temperature are kept at 35°C and 85°C, nanofluid concentration is kept at 0.1 and 1.0 volume% (vol.%) and the hot fluid flow rate are kept at 2 lpm and 10 lpm. Experiments were conducted with 16 runs as per MINITAB design software using graphene/water nanofluids in the corrugated plate type heat exchanger.  The nanofluid thermal conductivity was determined using the mixing rule for different nanofluid concentrations ranging from 0.1 to 1.0%. Normal, Pareto, Residual, Main and Interaction effects, Contour Plots were drawn. The Analysis of Variance (ANOVA) of test results depict that the hot fluid temperature and nanofluid concentration have significant effect on the thermal conductivity of graphene/water nanofluid (response variable)

Saccharification and Single Step Fermentation of Cassava Peel by Mixed Culture of Saccharomycopsis fibuligera NCIM 3161 and Zymomonas mobilis MTCC 92

Abstract The main objective of this study was to utilize the cassava peel by saccharification and single step fermentation (SSF) by mixed culture of Saccharomycopsis fibuligera NCIM 3161 and Zymomonas mobilis MTCC 92. Single step fermentation was performed in conical flasks with various concentrations of cassava peel (30, 50, 70 and 90 g/L), pH (3.5, 4.5 and 5.5), temperature (37, 47 and 57°C), reaction time (72, 720 and 168 h), inoculum size (5, 10 and 15 % v/v) and agitation speed (50, 100 and 150 rpm). Cell growth was identified by measuring optical density at 660 nm. The total reducing sugars were determined by centrifuging at 5000 rpm for 10 min by 3,5-dinitrosalicylic acid method. Starch concentration was estimated by anthrone method. Ethanol concentration was determined by acid dichromate method. The optimum process conditions were substrate concentration of 70 g/L, pH of 4.5, temperature of 37°C, reaction time of 120 h, inoculum size of 10 % (v/v) and agitation speed of 100 rpm. Under these conditions, the highest ethanol concentration of 26.46 g/L was obtained for cassava peel (93.75 % of theoretical yield)