Woven glass fiber reinforced with epoxy matrix composites are manufactured considering different glass/epoxy proportions and vibration analyses of the laminated composite plates subjected to free vibrations have been examined. The tensile and flexural strength of composites were evaluated by following ASTM standards. Free vibration of the composite specimen characteristics is studied using a Fast Fourier Transform analyzer, accelerometer using impact hammer excitation. The fast response functions are studied in order to clearly understand the vibration characteristics of the specimens. The experimentally obtained results of the rectangular composite plates are compared with the analytical results obtained from Nastran. The results showed a good agreement. It was observed that as the number of layers of the composite specimen increased, the frequency response also increased.

In the present study, an interaction relationship has been developed by following a design matrix consisting of few combinations of tool rotational speed, traverse speed, and tool pin configurations to understand the evolution of structural and mechanical properties of friction stir welded (FSW) Al-Mg alloy. The welded Al-Mg alloy was characterized in terms of microstructure to analysis different zones of weld using optical and scanning electron microscope. The mechanical properties such as bulk & micro hardness, and tensile strength were evaluated using Brinell, Vickers hardness tester, and tensometer respectively. The weld textures and grain size of the three different zones obtained using electron beam scattered diffraction (EBSD). Further, confirmation test was conducted to ensure the reliability. Results reveal that process parameters and tool pin profile influence the properties of the friction stir welded joints. The straight square pin configuration was the optimal structure for friction stir welding of Al-Mg alloy at a rotational speed of 1000 rpm and a welding speed of 40 mm/min, produced defect free weld with highest tensile strength of 136.25 MPa, bulk-hardness of 80.41 BHN, micro-hardness of 82 VHN in comparison with rest of the combinations considered in the investigation under same conditions. A fine recrystallized equiaxed grain with a partial fiber texture was evolved in the nugget zone. The measured experimental values agreed with the predicted data well.

Biodiesel is marketed as a long-term renewable fuel that may partially replace fossil fuels in transportation while also helping to reduce global warming. The current study is focused on using waste animal fat as a feedstock for biodiesel production. Sulfuric acid (H2SO4) and potassium hydroxide (KOH) are used as catalysts, with methanol as an alcohol. Temperature at 60°C, reaction time 2 hrs for acid catalyst, and 55°C, reaction time 90 min for base catalyst with a methanol to oil ratio of 5 : 1 are the experimental and optimized process conditions. With the H2SO4 catalyst, the biodiesel yield was 65.7%, while with the KOH catalyst, it was 48.8%. The ASTM standards are used to compare and study the physicochemical characteristics. This study offers an environmentally friendly solution to a global problem of atmospheric pollution, and at the same time, it shows a commercial alternative to reduce the ecological impact caused by waste animal fat.

No abstract

No abstract