Rajalakshmi Engineering College

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.

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.

Precast technology is globally preferred because of its superior structural elements, reduced time of construction, and cost savings. Precast concrete structures have faced challenges in past earthquakes due to the failure of structural element connections. The connection’s performance mainly determines the overall structure’s behaviour under lateral loading. The study investigates the behaviour of PC beam-column dry mechanical connections and a reference monolithic connection under reverse cyclic loading. The precast connections are (i) Billet Tie Rod (BTR) and (ii) Billet Tie Rod with Horizontal Dowel (BTR-HD). The behaviour difference between the precast connection and the reference monolithic specimen (MO) was examined in terms of ultimate load-carrying-capacity, hysteresis, ductility, post-elastic strength enhancement factor, and energy dissipation. The PC BTR-HD specimen demonstrated outstanding performance in ultimate load, energy dissipation and ductility when compared to the MO connection.

Carbon nanotubes (CNTs) are promising nanofillers for enhancing the performance of chloroprene rubber/natural rubber (CR/NR) composites. In this study, CNTs were incorporated into CR/NR blends at loadings up to 10 phr using melt mixing, and their influence on curing, mechanical and physical properties was systematically evaluated. Key properties studied included tensile strength, stress at 100

Biomaterials and tissue engineering are crucial in wound healing and replacement surgeries. In this study, a synergistic composite coating was developed on 316 L stainless steel by integrating electrophoretically deposited nanohydroxyapatite (nHAP) with electrospun polymer nanofibers. The nHAP layer provided a bioactive, mineral-rich interface mimicking natural bone, whereas the polymer nanofiber mat enhanced mechanical stability, controlled degradation, and improved cellular attachment. Comprehensive characterization through hardness testing, FTIR, XRD, and SEM confirmed the structural integrity, molecular interactions, and morphological features of the fabricated scaffolds. Microstructural analysis confirmed uniform deposition and strong interfacial bonding between the two coating layers. Electrochemical testing demonstrated significantly improved corrosion resistance compared to uncoated substrates. In vitro assays revealed enhanced osteoblast adhesion and proliferation, highlighting the coating’s cytocompatibility. The combined approach leverages the strengths of both ceramic and polymer components, offering a promising surface modification strategy for next-generation orthopedic implants aimed at improving long-term integration and functional outcomes.