Gandhigram Rural Institute

The novelty of the study lies in the comparative analysis of alkali oxides and their corresponding fluoride counterparts as modifiers within a glass system. The melt quenching technique was employed to synthesize the glass composition; 49P2O5 + 20TeO2 + 10MX + 10BaCO3 + 10ZnF2 + 1Sm2O3 (MX = Li2CO3, LiF, Na2CO3, NaF, K2CO3 and KF). The amorphous nature was confirmed by XRD analysis, and the optical properties, such as band gap, Urbach energy and band tail parameters, provides insights into the nature of the materials. Lower Urbach energy (∆E) values confirm the reduced disorderliness in the structure of the present glasses. The ionic and covalent nature of the glass was also examined. Radiation attenuation properties were evaluated using Phy-X software. At 0.5 cm thickness, all the prepared glasses exhibit full gamma-ray shielding at low energies (0.015–0.02 MeV), and the efficiency declines noticeably as energy increases. The TVL analysis reveals that the PTSBZ:KF sample offers optimal low-energy shielding, while the PTSBZ:NF glass sample exhibits superior attenuation at higher energies, highlighting energy-dependent performance. The results demonstrate that lower HVL, TVL, and MFP along with higher LAC and MAC values validate the present glasses as effective materials for radiation attenuation applications.

This study investigates the cyclic voltammetry driven electrochemical polymerization of 3-amino-1,2,4-triazole on Cu-Ni (90/10) alloy and the development of 3-amino-1,2,4-triazole based composite coatings incorporated with inorganic oxides (TiO2, ZnO, CeO2 and SiO2). The corrosion inhibition performance of the resulting polymeric and composite coatings in neutral environment was assessed using electrochemical impedance and potentiodynamic polarization measurements. Further, it was characterized using Fourier transform infrared spectroscopy and X-ray diffraction analysis. The morphological analysis of polymeric and composite film surfaces was performed using Atomic force microscopy and Scanning electron microscopy analysis. The results of electrochemical and polarization studies clearly demonstrated the significant enhanced corrosion resistance for the composite coatings compared to the 3-amino-1,2,4-triazole. This improved performance is attributed to the oxide nanoparticles sealing the coating defects such as pores, cracks and providing enhanced barrier properties. It also provides a synergistic corrosion inhibition effect between the organic polymeric matrix and the inorganic fillers. Poly-3-amino-1,2,4-triazole coatings incorporated with TiO2, ZnO, CeO2, and SiO2 were electropolymerized on Cu–Ni (90/10) alloy. Electrochemical, spectroscopic, surface morphological, and elemental analyses confirmed enhanced corrosion resistance. Among them, the TiO2 composite showed superior protection due to compact, defect-free films and strong organic–inorganic interaction providing effective barrier properties in 3.5

The past decade’s surge in electrification, digital technologies, and clean-energy systems has elevated rare-earth elements (REEs) to strategic importance, particularly for high-performance magnets, motors, sensors, and optical systems. However, existing REE literature remains fragmented across geological occurrence, reserves, mine production, and separation capacity, with inconsistencies in reporting units and scope. This study addresses this gap by developing a source-verified, unit-consistent synthesis of the global REE value chain from geological endowment to midstream separation. We quantify global reserves (Mt REO-equivalent), mine output (kt REO·yr⁻¹), and separation capacity (t REO·yr⁻¹ or NdPr-oxide·yr⁻¹) for 2024/25, and evaluate structural concentration using the Herfindahl–Hirschman Index (HHI). Results show a progressive tightening of supply from reserves to production and further to separation, identifying midstream processing as the principal bottleneck. We further assess announced separation “pipeline” projects across Australia, the United States, Europe, and Vietnam, highlighting their potential to expand NdPr availability and strengthen heavy rare earth (Dy, Tb) supply. A focused analysis of India integrates data on resource endowment, production, trade, and refining capacity, revealing a marked contrast between significant geological resources and limited current production and processing. By consolidating dispersed datasets into a unified analytical framework, this study provides a transparent, policy-relevant baseline for assessing REE supply security and identifies separation capacity expansion as the most effective lever for near-term diversification.

Synchronization in coupled nonlinear oscillators is central to understanding collective behavior in physics, biology, and engineering. This work presents a Koopman operator-based framework for analyzing synchronization in diffusively coupled Van der Pol oscillators, with a brief extension to a bio-inspired fish robot model. Traditional time-domain and Hilbert-phase analyses identify phase coherence for sufficiently strong coupling, but the Koopman approach provides a richer operator-theoretic view by lifting nonlinear dynamics into a linear observable space. Extended Dynamic Mode Decomposition (EDMD) is employed to compute Koopman spectra and modes, revealing oscillatory stability and latent synchronization manifolds. Data-driven embeddings using Principal Component Analysis (PCA), t-distributed stochastic neighbor embedding (t-SNE), and K-means uncover coherent structures and phase-locking regimes. Further, residual diagnostics quantify model fidelity and allow estimation of coupling strength. Results demonstrate robust synchronization across small oscillator networks and confirm scalability up to N=100 . The study highlights Koopman analysis as a powerful alternative to classical phase-reduction, offering both microscopic residual insights and macroscopic coherence characterization, with broader implications for nonlinear networks in engineering and bio-inspired systems.

In this study, we analyze the saddle point of the mean-field stochastic mixed delay differential system with Teugels martingales over an infinitely long time horizon. In addition to this, the mean-field term is generalized to the Fr é chet differentiable functional. Moreover, when the control domain is convex, the transversality condition is employed to establish the essential criteria for optimality, including the stochastic maximum principle (saddle point) and necessary conditions for optimality. Finally, the optimal irreversible investment problem is demonstrated with the help of the aforementioned theoretical work.