Amidst different types of energy storage systems, electric double-layer capacitors (EDLCs), also known as supercapacitors, have received considerable attention as energy storage alternatives due to their advantageous characteristics: high power density, long-life cycle, lightweight, safe operations, and fast charge-discharge rates. This work addresses these EDLC devices and has been divided into two parts. In the former, the synthesis and characterization of activated carbon ber-felt (ACFF) electrodes from textile PAN ber have been provided. In the latter, electrochemical characterization of the ACFF electrodes in potassium hydroxide solutions (aqueous-based) and in potassium hydroxide-glycerol hybrid electrolytes (glycerol-based electrolytes) have been investigated. The synthesis of ACFF electrodes via two-step oxidation, carbonization, and physical activation resulted in low-cost and binder-free electrodes containing mostly micropores (maximum pore width of 3 nm) and a speci c surface area of 1875 m 2 g − 1 . Electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge techniques were carried out in a symmetric two-electrode setup at room temperature. The results showed that ACFF-based EDLCs in aqueous-based electrolyte (2 M KOH) exhibited low electrolyte resistance (0.44 ± 0.04 Ω cm 2 ) and high gravimetric capacitance (129 ± 6 F g − 1 at 1 mV s − 1 ). Although ACFF-based EDLCs in glycerol-based electrolytes exhibited high electrolyte resistance (> 17 ± 2 Ω cm 2 ), they are hybrid green-electrolytes that support a large potential window (< 2.5), which is greater than that of aqueous electrolytes (≈ 1 V). Crude glycerol, the main byproduct in biodiesel production, is non-toxic, relatively safe, and low-cost. The advantages and disadvantages of aqueous and glycerol-based electrolytes have been discussed.

Amidst different types of energy storage systems, electric double-layer capacitors (EDLCs), also known as supercapacitors, have received considerable attention as energy storage alternatives due to their advantageous characteristics: high power density, long-life cycle, lightweight, safe operations, and fast charge-discharge rates. This work addresses these EDLC devices and has been divided into two parts. In the former, the synthesis and characterization of activated carbon fiber-felt (ACFF) electrodes from textile PAN fiber have been provided. In the latter, electrochemical characterization of the ACFF electrodes in potassium hydroxide solutions (aqueous-based) and in potassium hydroxide-glycerol hybrid electrolytes (glycerol-based electrolytes) have been investigated. The synthesis of ACFF electrodes via two-step oxidation, carbonization, and physical activation resulted in low-cost and binder-free electrodes containing mostly micropores (maximum pore width of 3 nm) and a specific surface area of 1875 m2 g− 1. Electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge-discharge techniques were carried out in a symmetric two-electrode setup at room temperature. The results showed that ACFF-based EDLCs in aqueous-based electrolyte (2 M KOH) exhibited low electrolyte resistance (0.44 ± 0.04 Ω cm2) and high gravimetric capacitance (129 ± 6 F g− 1 at 1 mV s − 1). Although ACFF-based EDLCs in glycerol-based electrolytes exhibited high electrolyte resistance (> 17 ± 2 Ω cm2), they are hybrid green-electrolytes that support a large potential window (< 2.5), which is greater than that of aqueous electrolytes (≈ 1 V). Crude glycerol, the main byproduct in biodiesel production, is non-toxic, relatively safe, and low-cost. The advantages and disadvantages of aqueous and glycerol-based electrolytes have been discussed.

The objective of this work was to determine the fatigue life of wire materials by rotary bending and to identify parameters of mechanical loading and deformation associated with the characteristics of the rupture generated by fatigue to prevent failures. An AWS A5.18 welding wire with diameter 0.80 mm was used as the specimen. The welding wire specimens were subjected to an average rotation of 611.3 rpm with a bending radius of 80 mm. The results show that the welding wire supports around 10,000 cycles until its fracture, and SEM image analysis indicates a combined fracture of failure and ductile fractures.

This work introduces an experimental method in mechanical recycling for carbon fiber-reinforced epoxy-resin burr originated from manufacturing process. The recycling process consists of a manufactured plastic chamber and a Dremel300® rotary tool.MEV analysis, volume fraction and tensile test characterized the powder acquired from the process. The powder produced is not homogeneous and it is indicated for surface finishing and manufacture of particulate composites.

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