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Shea nut oil has been confirmed as a feasible and sustainable biofuel source and may be used to improve the economics of biodiesel production. However, there is need to evaluate the best route for achieving optimum yield and best quality. Therefore, two processes were investigated in this study-acid catalyzed and supercritical transesterification processes. Shea nut seeds were collected, its oil mechanically extracted thereafter, and the physiochemical properties were analyzed. In the acid catalysed process, shea nut oil was transesterified into biodiesel using ethanol with sulphuric acid (H2SO4) as a catalyst. This gave a conversion of between 55wt% and 90wt% for temperatures between 20 o C and 90 o C. The optimum ratio of ethanol/oil was found to be 30:1 at 80 o C for reaction time of 120 minutes. While for supercritical transesterification process (without acid), the conversion was between 55wt% and 82.5wt% at temperatures between 220 o C and 300 o C. However, the optimum condition here was 20:1 ethanol/oil molar ratio, at 240 o C and 24 minutes reaction time. The biodiesel properties produced were evaluated and most of these conformed to Biodiesel Standard, ASTM D-6751 and the international standard, EN-14214. Also, the properties of Biodiesel produced by supercritical process seem better compared to that from the acid catalyzed process in line with the ASTM D-6751 and EN-14214 standards, thus a better option for diesel engines making supercritical transesterification a preferred option for biodiesel production from shea nut oil.

Residual stress are stresses that remains in an engineering material, especially metallic materials, after the original applied load has been removed. Its measurement will help reveal areas in fabricated materials highly stressed. This paper presents a design of a portable residual stress measuring device based on the magnetic barkhausen noise principle. This was achieved by using two permanent magnets, a pickup coil, amplifier and an analogue to digital converter to create the hardware. The software was designed using LabVIEW 2019. After fabrication, measuring experiments on mild steel materials were conducted and the results obtained from using the device for measurement were compared to simulated values (Simufact.Weld 6.0) CAD software. Comparing its results with that obtained from Simulation showed an R 2 value of 77.47% with a strong correlation of 0.831and a P-value of 0.0071 which was less than the 0.05 alpha level taken. This device can be adopted in weld residual stress measurement by artisans and roadside welders for effective minimization of residual stress and failures associated with it.