Bannari Amman Institute of Technology

Platinum (Pt) persists as an exceptionally prevalent catalyst material in the proton exchange membrane fuel cells (PEMFCs), especially for cathodic oxygen reduction kinetics. However, the high cost and limited supply of Pt are driving interest in bio-based catalyst systems. In this review, three families of such catalysts, which include enzymes, metalloporphyrins, and biomass-derived carbon, are evaluated for their performance under PEMFC-relevant conditions. Rather than evaluating these as potential alternatives, this review focuses on their four-electron route driving capabilities, impurity sensitivity, and stability. Contemporary reports indicate that laccase-based systems, Fe/Co porphyrinic carbons, and microbial-templated Pd and Pt catalysts can attain activity levels comparable to Pt/C when immobilization and electronic coupling are effectively regulated. The primary concerns lie in durability and poisoning, with sulfur species and CO being detrimental to various biological templates. Furthermore, challenges persist regarding scalability and reproducibility because, unlike the conventional heterogeneous catalysts used in PEMFCs, bio-catalysts are contingent upon parameters including ligand chemistry, protein structural arrangement, and microbial growth. This makes the production process and maintenance of batch uniformity laborious. Although recent advancements have mitigated performance limitations, mechanistic understanding, operational longevity, and manufacturing scalability remain critical considerations. Overcoming these challenges will establish biocatalysts as a viable alternative to traditional precious-metal catalysts in PEMFCs.

Hydrogen bond liquid crystal complexes (HBLCs) are successfully isolated from the mesogenic compounds of 4-n-alkyloxybenzoic acid (nOBA, n = 10 and 11), and the non-mesogenic compound of 1,3‑phenylenediacetic acid. Formation of H-bonds between the mesogen and non-mesogen and the presence of functional groups are detailed using FTIR analysis, whereas, UV–Vis spectroscopic analysis endorses the nature of the electronic transition and optical properties of the HBLC complexes. Polarizing optical microscopy (POM) textural analysis authenticates the presence of induced mesophases along with transition temperatures. Mesophase transition temperatures and changes in enthalpy, entropy of the resultant mesogens is assessed by differential scanning calorimetry (DSC) studies. It is noticed that the formation of H-bonds induces rich phase polymorphism with an extended mesogenic range. Furthermore, the thermodynamic equilibrium of the HBLC system is confirmed by the enthalpy calculation, which shows that the amount of energy absorbed by the system is equal to the amount of energy released by the system. Another interesting observation is that the thermochromic phenomenon exhibited in the nematic phase offers valuable insights for diverse sensor applications. The repeated thermal scanning and positive entropy values favour the thermally stable mesogenic HBLCs. Moreover, the obtained result elucidates the critical role of hydrogen bonding and molecular ordering in governing the mesomorphic behavior of the synthesized HBLC complex.

Waste materials like flyash, bottom ash, slag and construction and demolition (C D) debris are generated at a rapid rate creating problems of disposal and environmental degradation. Reuse of these materials as foundation medium or as backfilling reduces disposal problems which paves way for sustainable construction. Soil reinforcement with the use of geosynthetics is a method globally practiced for earth reinforcement in geotechnical engineering applications. This study is aimed at exploring the performance of natural and synthetic reinforcements on Waste Foundry Sand (WFS). This waste being generated from foundry industries would otherwise lead to land disposal problems. Natural Bamboo material in the form of reinforcement is gaining attention. This has been used recently as the tensile strength of the material is higher than the commercial geogrid material. This helps in the lateral restraint and stability of the reinforced foundation system thereby enhancing the bearing capacity. This research focuses on the identification of ideal geometric parameters of reinforcements with the objective of enhancing the load bearing capacity. The laboratory model test results have identified depths of reinforcement, diameters of the reinforcing layers and the spacing between the reinforcement layers as the key elements for the increased Bearing capacity ratio (BCR). The optimal geometric parameters are determined as u/B = 0.25, D/B = 3, h/B = 0.25 0.5, and l/B = 0.6. Bamboo grids offered higher bearing capacity which is 16–23

Binary mixtures with an equimolar ratio are formed by the formation of hydrogen-bonded liquid crystalline complexes. The complexes are synthesized from precursors formed between α-Keto Glutaric acid (KGA) and hexyloxy benzoic acid (6BAO), as well as between α-Keto Glutaric acid (KGA) and dodecyloxy benzoic acid (12BAO). In order to make a comprehensive analysis of the mesomorphic properties that are presented, exhaustive studies are carried out employing optical, thermal, and spectral characterization techniques. The isolated binary mixes show three different types of mesophases: nematic, smectic C, and smectic G. Fourier Transform Infrared Spectroscopy (FT-IR) is used to validate the intermolecular hydrogen bonding by chemical analysis. Optical analysis is performed using a Polarizing Optical Microscope (POM) to confirm the mesophases and the phase variance exhibited. A Differential Scanning Calorimeter (DSC) is used in thermal analysis to ascertain enthalpy values, phase transition temperatures, and other thermal characteristics associated with the substance being investigated in the current research.

Natural fibers have become a viable substitute for traditional synthetic fibers at composites owing to equivalent mechanical qualities, economic efficiency, environmental durability, and high strength ratio. The primary objective of study were analyze and evaluate mechanical characteristics of composites from natural agave americana and sisal fibers. The feasibility of the fibers as alternatives to aramid, carbon fibers or glass, was assessed. Subsequent to hand lay-up, their tensile and flexural strengths, as well as impact, was assessed using mechanical test. The incorporation of sisal (30