In this study, waste cooking oil (WCO) was used as a feedstock for biodiesel production, where the pretreatment of WCO was performed using mineral acids to reduce the acid value. The response surface methodology (RSM) was used to create an interaction for different operating parameters that affect biodiesel yield. The optimised biodiesel yield was 93% at a reaction temperature of 57.50 °C, catalyst concentration 0.25 w/w, methanol to oil ratio 8.50:1, reaction stirring speed 600 rpm, and a reaction time of 3 h. Physicochemical properties, including lower heating value, density, viscosity, cloud point, and flash point of biodiesel blends, were determined using American Society for Testing and Materials (ASTM) standards. Biodiesel blends B10, B20, B30, B40, and B50 were tested on a compression ignition engine. Engine performance parameters, including brake torque (BT), brake power (BP), brake thermal efficiency (BTE), and brake specific fuel consumption (BSFC) were determined using biodiesel blends and compared to that of high-speed diesel. The average BT reduction for biodiesel blends compared to HSD at 3000 rpm were found to be 1.45%, 2%, 2.2%, 3.09%, and 3.5% for B10, B20, B30, B40, and B50, respectively. The average increase in BSFC for biodiesel blends compared to HSD at 3500 rpm were found to be 1.61%, 5.73%, 8.8%, 12.76%, and 18% for B10, B20, B30, B40, and B50, respectively.

Biodiesel is a promising sector worldwide and is experiencing significant and rapid growth. Several studies have been undertaken to utilize homogeneous base catalysts in the form of KOH to develop biodiesel in order to establish a commercially viable and sustainable biodiesel industry. This research centers around extracting potassium hydroxide (KOH) from banana trunks and employing it in the transesterification reaction to generate biodiesel from waste cooking oil (WCO). Various operational factors were analyzed for their relative impact on biodiesel output, and after optimizing the reaction parameters, a conversion rate of 95.33% was achieved while maintaining a reaction period of 2.5 h, a methanol-to-oil molar ratio of 15:1, and a catalyst quantity of 5 wt%. Response surface methodology (RSM) and artificial neural network (ANN) models were implemented to improve and optimize these reaction parameters for the purpose of obtaining the maximum biodiesel output. Consequently, remarkably higher yields of 95.33% and 95.53% were achieved by RSM and ANN, respectively, with a quite little margin of error of 0.0003%. This study showcases immense promise for the large-scale commercial production of biodiesel.

Cardiovascular prosthetic devices, stents, prosthetic valves, heart-assist pumps, etc., operate in a wide regime of flows characterized by fluid dynamic flow structures, laminar and turbulent flows, unsteady flow patterns, vortices, and other flow disturbances. These flow disturbances cause shear stress, hemolysis, platelet activation, thrombosis, and other types of blood trauma, leading to neointimal hyperplasia, neoatherosclerosis, pannus overgrowth, etc. Couette-type blood-shearing devices are used to simulate and then clinically measure blood trauma, after which the results can be used to assist in the design of the cardiovascular prosthetic devices. However, previous designs for such blood-shearing devices do not cover the whole range of flow shear, Reynolds numbers, and Taylor numbers characteristic of all types of implanted cardiovascular prosthetic devices, limiting the general applicability of clinical data obtained by tests using different blood-shearing devices. This paper presents the key fluid dynamic parameters that must be met. Based on this, Couette device geometric parameters such as diameter, gap, flow rate, shear stress, and temperature are carefully selected to ensure that the device’s Reynolds numbers, Taylor number, operating temperature, and shear stress in the gap fully represent the flow characteristics across the operating range of all types of cardiovascular prosthetic devices. The outcome is that the numerical data obtained from the presented device can be related to all such prosthetic devices and all flow conditions, making the results obtained with such shearing devices widely applicable across the field. Numerical simulations illustrate that the types of flow patterns generated in the blood-shearing device meet the above criteria.