By increasing the environmental concerns and depletion of petroleum resources, bio-based resins have gained interest. Recently, lignin, vanillin (4-hydroxy-3-methoxybenzaldehyde), and divanillin (6,6′-dihydroxy-5,5′-dimethoxybiphenyl-3,3′-dicarbaldehyde)-based resins have attracted attention due to the low cost, environmental benefits, good thermal stability, excellent mechanical properties, and suitability for high-performance natural fiber composite applications. This review highlights the recent use of lignin, vanillin, and divanillin-based resins with natural fiber composites and their synthesized processes. Finally, discussions are made on the curing kinetics, mechanical properties, flame retardancy, and bio-based resins’ adhesion property.

In the present study, the investigation on photochemical machining (PCM) of stainless steel (SS-304) by ferric chloride as etchant is reported. SS-304 is machined by PCM process to obtain accurate dimensions and better geometrical features. Weighted grey relational analysis (WGRA) technique is used in optimization of PCM process parameters. DoE (L₂₇) orthogonal array is applied to evaluate machining parameters, such as concentration of etchant, etching time, and temperature of etchant. The multiobjective optimization technique is used to optimize material removal rate (MRR), surface roughness (R_a), undercut (U_c) and etch factor (EF). Weighted grey relational grade is calculated to minimize U_c and surface roughness and to maximize MRR and EF. The quality characteristics MRR, EF, U_c, and R_a are reporting the improvement after the confirmatory test. The optimum machining parameters are processed to manufacture the microfluidic channel used in biomedical applications. The microfluidic channels and its assembly with Y-type for mixing of fluid with a size of 100 µm, 200 µm, and 300 µm are developed and investigated.

Aiming to generate wealth from waste and due to their significant fire threats to forests and their rich cellulose content, lignocellulosic pine needle fibers (PNFs) are utilized in this study as a reinforcement of the thermoplastic elastomer styrene ethylene butylene styrene (SEBS) matrix to create environmentally friendly and economical PNF/SEBS composites using a maleic anhydride-grafted SEBS compatibilizer. The chemical interaction in the composites studied by FTIR shows that strong ester bonds are formed between reinforcing PNF, the compatibilizer, and the SEBS polymer, leading to strong interfacial adhesion between the PNF and SEBS in the composites. This strong adhesion in the composite exhibits higher mechanical properties than the matrix polymer indicating a 1150 % higher modulus and a 50 % higher strength relative to the matrix. Further, the SEM pictures of the tensile-fractured samples of the composites validate this strong interface. Finally, the prepared composites show better dynamic mechanical behavior indicating higher storage and loss moduli and T_g than the matrix polymer suggesting their potential for engineering applications.

Friction & wear are main reasons for mechanical failures of heavy loaded gearboxes. However, reformed lubricant can be used to control this. This study investigates the tribological behavior of composite Nano size particles with ZDDP as add-on in EP gearbox oil for various concentrations of composite additive - 0.005, 0.01, 0.02 wt.%. All tests have conducted under variable loads (60 N, 80 N & 100N) & sliding velocities (0.65m/s, 1.05 m/s & 1.50 m/s). The experimental reading on antiwear & antifriction parameters for gear EP oil has been tested on pin on disc instrument. The response surface approach was used to build the experiment's design (DOE), which examined the ideal friction coefficient & wear volume loss in EP 220 Lubricant. Outcomes from the experimental study have been compared for two gear EP oils to indicate influence of various parameters like nanoparticles blend %, load and sliding velocity. It is found that the blending of gear EP oil with composite additives & ZDDP diminishes the wear & COF by 11.98 % and 9.81 % individually under various load & speed working conditions.