Kongunadu Arts and Science College, is an autonomous arts and science college located at Coimbatore, Tamil Nadu. The college is affiliated with Bharathiar University. The college has been recognized as the 'College of Excellence' by the University Grants Commission and ranked among the best colleges in India.
This paper introduces a new graph parameter that combines the concepts of the geodetic number and the r-dynamic chromatic number. The proposed parameter captures both the geodesic structure of a graph and the constraints imposed by r-dynamic coloring. Fundamental properties of this newly defined invariant are established and general bounds in terms of standard graph parameters are derived. Further, Several families of tree graphs are examined, for which exact values are obtained. These results illustrate the interaction between geodetic properties and r-dynamic coloring and provide a useful framework for further research in this area.
The contamination of aquatic ecosystems by heavy metals poses a critical risk to human health and environmental integrity. In response, functional oxide nanomaterials and their composites have emerged as highly effective candidates for water purification, owing to their exceptional surface area, tunable porosity, chemical stability, and strong adsorption potential. This review offers a comprehensive and analytical perspective on the design, synthesis, and deployment of key oxide-based nanomaterials - including titanium dioxide, zinc oxide, iron oxides, and manganese oxides - as well as advanced hybrid composites engineered for the removal of toxic metal ions from water. Unlike conventional summaries, this work emphasizes performance comparisons, highlights structure–function relationships, and elucidates key removal mechanisms such as adsorption, redox reactions, ion exchange, and photocatalysis. It also addresses current limitations related to material reusability, synthesis cost, and field applicability, and proposes future-oriented strategies to overcome these barriers. Through integrated insights and a forward-looking approach, this review aims to support the advancement of next-generation nanomaterials for scalable, cost-effective, and environmentally sustainable heavy metal remediation.
This study quantified the abundance, distribution, and characteristics of microplastics in surface water and sediments from five lakes in the Coimbatore District: Kumaraswamy Lake, Ukkadam Lake, Kuruchi Lake, Singanallur Lake, and Sulur Lake. The highest microplastic abundance was found in the surface water of Kuruchi Lake (14.08 f 0.63 particles/L) at site S5 during the monsoon, and in the surface sediments of Kumaraswamy Lake (13.33 f 0.33 particles/g) at site S6 during summer. Spatial distribution patterns indicated that lakes receiving urban runoff, domestic wastewater inflow, and inputs from fishing and recreational activities exhibited higher microplastic concentrations. Seasonal variations showed elevated microplastic abundance in summer sediments and monsoon surface water samples. Microplastics were identified using Attenuated total reflectanceFourier Transform Infrared Spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC)), revealing Linear low-density polyethylene (LLDPE), High-density polyethylene (HDPE), Polyethylene terephthalate (PET), and Polypropylene (PP). These microplastic occurred in white, transparent, black, blue, yellow, and pink colors and appeared as films, fragments, thin pieces, and fibres. Characteristic DSC melting peaks were observed 200 degrees C for PET, 167.98 degrees C for PP, 126.70 degrees C for LLDPE, and 130.02 degrees C for HDPE. The lake's pollution load index is categorized as risk level 1, indicating a low level of microplastic pollution. The presence and distribution of these microplastics suggest potential ecological risks to freshwater organisms and possible implications for human health.
The stabilization of metastable amorphous phases is a crucial-materials processing strategy for minimizing resistance drift and improving the endurance and reliability of Phase Change (PcRAM) and Resistive memory (ReRAM) devices. As-deposited amorphous metal chalcogenide thin films exhibit high electrical resistance, which enables their operation as OFF-state in phase change memory device applications. However, they exhibit a metastable nature, which is detrimental to memory devices due to resistance drift over time, ultimately limiting the device's endurance and reliability. In this work, we demonstrate that low-energy Ar(+) ion irradiation can be used as a controlled method to induce atomic rearrangement and densification. This process effectively stabilizes the amorphous network of Se77.5-XTe20Sn2.5AgX (X = 2.5, and 7.5) thin films. The influence of irradiation on the structural, morphological, optical, and electrical properties is systematically investigated to confirm the evolution of amorphous stabilization. The comprehensive analysis confirms that Ar(+) ion irradiation has effectively reduced the metastability and also has improved the structural uniformity, leading to enhanced electrical stability. Our results and findings demonstrate that low-energy ion treatment is a promising strategy for improving the functional reliability of Se-Te-Sn-Ag (STSA) thin films for memory, optoelectronic, and thermoelectric applications.
In the present investigation, ZnO nanoparticles synthesized via a green route using Averrhoa bilimbi (ZnO B0 and B1) and Brassica oleracea (ZnO C0 and C1) extracts demonstrated distinct photocatalytic performance as a function of their structural and defect characteristics. X-ray diffraction and Williamson-Hall (W-H) analyses revealed that ZnO (B1) (synthesized with Averrhoa bilimbi fruit extract and calcined) exhibited a crystallite size of 44.8 nm and a moderate lattice strain of 0.0011, while ZnO (C1) (synthesized using Brassica oleracea var. botrytis leaf extract and calcined) exhibited a larger crystallite size of 58.6 nm and a relatively higher strain of 0.0015. These microstructural variations played a pivotal role in influencing the photocatalytic behavior under solar irradiation, as further supported by EPR and XPS analyses, which revealed a higher concentration of oxygen vacancies and defect states responsible for enhanced charge separation and activity. ZnO (B1) achieved the highest methylene blue (MB) degradation efficiency, attributed to its balanced defect concentration and strain-induced surface activity. In contrast, despite improved crystallinity, ZnO (C1) exhibited reduced activity, likely due to excessive lattice strain and oversaturation of defect sites, which promoted electron-hole recombination. Kinetic analysis based on the Langmuir-Hinshelwood model and thermodynamic evaluation further supported the structure-driven enhanced photocatalytic behavior of ZnO (B1). Overall, this study establishes, for the first time, a systematic correlation between Williamson-Hall microstructural parameters and the photocatalytic kinetic and thermodynamic behavior of green-synthesized ZnO nanoparticles.
