St. Joseph's College of Engineering is a higher education institution in Chennai, India. It is under the administration of the St. Joseph's Educational Trust. The college is affiliated to the Anna University, Chennai.
A Sn-doped Eu 2 O 3 /α-MnO 2 nanocomposite was synthesized via a one-pot chemical co-precipitation method and evaluated as a noble-metal-free electrocatalyst for the oxygen evolution reaction (OER) in alkaline media. X-ray diffraction (XRD) confirmed the formation of tetragonal α-MnO 2 with well-dispersed cubic Eu 2 O 3 nanodomains. At the same time, the absence of distinct Sn-based secondary phases suggested effective lattice incorporation or high dispersion of Sn species. Halder–Wagner analysis revealed a reduction in crystallite size and changes in microstrain following Eu₂O₃ incorporation and Sn modification. High-resolution transmission electron microscopy (HRTEM) demonstrated well-defined lattice fringes with clear interplanar spacings, confirming high crystallinity and heterointerface formation. In contrast, selected-area electron diffraction patterns revealed the polycrystalline nature of the nanocomposite. X-ray photoelectron spectroscopy (XPS) confirmed stable Eu³⁺ and Sn⁴⁺ oxidation states, mixed Mn 3 + /Mn 4+ redox chemistry, and an enhanced concentration of oxygen vacancies. Electrochemical investigations showed that the Sn–Eu 2 O 3 /α-MnO 2 electrode exhibits improved charge-transfer characteristics and moderate enhancement of OER activity, delivering a low overpotential of 350 mV at 10 mA cm −2 , a reduced Tafel slope, improved charge-transfer characteristics, and increased interfacial capacitive behaviour. The enhanced electrocatalytic performance is attributed to the synergistic effects of Sn-induced defect engineering, Eu 2 O 3 -mediated interfacial charge modulation, and optimized Mn redox chemistry, highlighting the potential of this nanocomposite for efficient alkaline OER applications. This study shows that using both rare-earth oxide promotion and heteroatom doping can change the electronic structure, defect chemistry, and interfacial charge transfer in MnO 2 -based catalysts. This combined approach offers a promising way to develop affordable and scalable noble-metal-free electrocatalysts for sustainable water-splitting technologies.
A Sn-doped Eu2O3 /α-MnO2 nanocomposite was synthesized via a one-pot chemical co-precipitation method and evaluated as a noble-metal-free electrocatalyst for the oxygen evolution reaction (OER) in alkaline media. X-ray diffraction (XRD) confirmed the formation of tetragonal α-MnO2 with well-dispersed cubic Eu2O3 nanodomains. At the same time, the absence of distinct Sn-based secondary phases suggested effective lattice incorporation or high dispersion of Sn species. Halder–Wagner analysis revealed a reduction in crystallite size and changes in microstrain following Eu₂O₃ incorporation and Sn modification. High-resolution transmission electron microscopy (HRTEM) demonstrated well-defined lattice fringes with clear interplanar spacings, confirming high crystallinity and heterointerface formation. In contrast, selected-area electron diffraction patterns revealed the polycrystalline nature of the nanocomposite. X-ray photoelectron spectroscopy (XPS) confirmed stable Eu³⁺ and Sn⁴⁺ oxidation states, mixed Mn3 +/Mn4+ redox chemistry, and an enhanced concentration of oxygen vacancies. Electrochemical investigations showed that the Sn–Eu2O3/α-MnO2 electrode exhibits improved charge-transfer characteristics and moderate enhancement of OER activity, delivering a low overpotential of 350 mV at 10 mA cm−2, a reduced Tafel slope, improved charge-transfer characteristics, and increased interfacial capacitive behaviour. The enhanced electrocatalytic performance is attributed to the synergistic effects of Sn-induced defect engineering, Eu2O3-mediated interfacial charge modulation, and optimized Mn redox chemistry, highlighting the potential of this nanocomposite for efficient alkaline OER applications. This study shows that using both rare-earth oxide promotion and heteroatom doping can change the electronic structure, defect chemistry, and interfacial charge transfer in MnO2-based catalysts. This combined approach offers a promising way to develop affordable and scalable noble-metal-free electrocatalysts for sustainable water-splitting technologies.
A subgraph of the square lattice with all of its inner faces being 4-cycles is called a square-cell configuration. Prior work has provided explicit expressions for the total and average distances between vertex pairs in symmetric square-cell configurations, including well-structured families such as hexagonal square-cell configurations H(n), trapezium square-cell configurations T(n,k), and bitrapezium square-cell configurations BT(n,k_1,k_2). In this article, we further extend the square-cell configuration from regular boundaries to irregular boundaries, which do not exhibit complete regularity or symmetry in their structure. We find the generalized expressions for the Wiener index and average distance of such irregular configurations, incorporating combinatorial and structural variations. Our results demonstrate how irregularity affects the growth and distribution of pairwise distances and provide a unifying framework that includes both symmetric and asymmetric square-cell graphs as exceptional cases. This generalization provides novel insights into the structural behaviour of square-cell frameworks characterized by complex or perturbed geometries.
Advancing microbiological research increasingly relies on the integration of digital technologies that enhance precision, scalability, and knowledge generation. This chapter per the authors explores how artificial intelligence, machine learning, big data analytics, digital twins, automation, and smart laboratory systems are transforming experimental design, microbial analysis, and applied research. Key focus areas include AI-driven discovery pipelines, computational modeling of microbial systems, high-throughput data handling, and digitally enabled biosafety and quality assurance practices. Applications across clinical microbiology, environmental monitoring, industrial biotechnology, and antimicrobial research are highlighted, alongside challenges related to data interoperability, ethics, and workforce preparedness. Overall, the chapter emphasizes the role of digitalization in accelerating innovation, improving reproducibility, and enabling sustainable and intelligent microbiological research ecosystems.
Groundwater samples collected from Chengalpattu District were analyzed for uranium using an LED fluorimeter. The measured values ranged between 0.02 μg L−1and 2.814 μg L−1, with an average concentration of 0.347 μg L−1. All measured values were within the permissible limits recommended by the World Health Organization and the International Commission on Radiological Protection. The study evaluated organ-specific uranium retention and committed equivalent doses for adults under chronic ingestion conditions using a hair-based compartmental biokinetic model. The results further confirm the previously reported non-uniform distribution of uranium among human organs and tissues, with tissue-specific retention characteristics governing its accumulation and residence time. Skeletal tissues, particularly cortical and trabecular bone volumes, exhibited the highest accumulation due to the strong affinity of uranyl ions for phosphate groups in hydroxyapatite, leading to prolonged retention and the largest contribution to internal radiation dose. In contrast, soft tissues, gastrointestinal tract segments, kidneys, and liver showed lower retention due to faster transfer and elimination rates. The gastrointestinal tract acts as the primary entry pathway, while the kidneys and urinary bladder play key roles in uranium clearance. Excretion analysis indicates that faeces elimination is the dominant pathway, followed by urinary and minor hair excretion. The highest committed equivalent doses were observed in bone surfaces, followed by other soft tissues, the lower large intestine wall, kidneys, upper large intestine wall, small intestine wall, stomach wall, and liver. The overall effective dose is mainly influenced by skeletal retention; however, the estimated doses across all locations remain low and well within international safety limits. These findings suggest minimal radiological health risk from chronic uranium ingestion in the study area and demonstrate that the hair compartmental biokinetic model is a reliable tool for long-term exposure and risk assessment.
