Netaji Subhas Open University

The geomagnetic storm of 10-11 May 2024 (G5-level) caused major ionospheric disturbances, providing an opportunity to examine its wide-ranging effects. This study analyzes ionospheric perturbations over mid- and high-latitude regions using Very Low Frequency (VLF) radio signal observations and TIMED/SABER satellite data in both hemispheres. Significant VLF amplitude anomalies were recorded along five paths (NAA-BRN, NAA-ASB, NAA-KIL, NAA-St. Johns, and NAA-Rothera), indicating strong lower ionospheric responses during and after the storm. High-latitude stations (KIL, Rothera) showed marked signal changes on 11 May, while the mid-latitude site (ASB) exhibited delayed peaks on 13 May. The associated solar energetic particle (SEP) event produced noticeable VLF fluctuations about 10 min after onset, particularly evident in high-resolution data. Wavelet analysis confirmed the presence of atmospheric gravity waves (15 s-30 min periods). SABER observations showed enhanced Nitric Oxide (NO) concentrations in the D- and E/F-regions, peaking on 11 May at 85-95 km and 110-130 km altitudes, respectively. These NO increases, caused by energetic particle precipitation, were observed across both hemispheres. Temperature profiles revealed storm-related warming above 95 km and cooling below 90 km in the Northern Hemisphere, linked to Joule heating, NO-induced infrared cooling, and vertical transport. The study highlights the value of combining ground-based VLF and satellite data to understand storm-time ionospheric dynamics, emphasizing hemispheric asymmetries, delayed responses, and regional variability in space weather effects.

The solid-liquid equilibrium solubility of 4-hydroxycoumarin (4-HC) was investigated in pure water, pure organic solvents (DMF, ACN, and DMSO), and their aqueous binary mixtures at eight temperatures ranging from 288.15 to 323.15 K under atmospheric pressure. Solubility measurements were performed using a gravimetric method employing a Shimadzu analytical balance, a thermostatic water bath, a shaker, and a vacuum filtration system. The effects of solvent composition and temperature on 4-HC solubility were systematically examined. The results indicate that solubility is strongly influenced by both factors, with significantly enhanced solubility in aqueous-organic mixtures compared to pure water. The van't Hoff model, the modified Apelblat equation, and the lambda h model were applied to correlate the experimental data, all showing good agreement with measured values. The resulting insights and model parameters provide useful guidance for optimizing pharmaceutical processes and improving industrial extraction and purification strategies for 4-HC.

The present study provides a detailed scientometric evaluation of 126,727 SDG-related LIS publications in India during the period 2015-2024 based on the data extracted from the OpenAlex database. It analyses the development of publications, citations, ollaborations and the distribution of topics among the SDGs. The study addresses the lack of large-scale, LIS-focused SDG assessment nationally. The results demonstrate that SDG-oriented LIS research has grown steadily over the past ten years. The RGR analysis indicates a continuous decrease of the proportional growth of both publications and citations, which is associated with a corresponding increase of the doubling time, indicating structural maturation of the research domain instead of accelerating expansion. Annual production dropped in 2024, but the total number of publications and citations continued to grow. This decline is likely caused by lag times in database indexing and partial coverage of recently published works.The Authorship Pattern and Citation Relationship quantify average citation impact by team size and indicate that larger collaborative teams have greater citation visibility. The SDG-wise distribution shows concentration in health, innovation, and governance-related SDGs, while some of the lower-output SDGs have comparatively high citation impact. Time-series predictions suggest a total of 25,257 publications by 2030, reflecting continued involvement in SDG-related LIS research. The results can help in planning research, strategies for collaboration and policy development in the sustainable knowledge ecosystem in India.

Given a simple graph G, let B-r(v) be the set of vertices at a distance of at most r from v. A vertex subset Cis an (r, <= & ell;)-locating-dominating code of type A or (r, <= & ell;)-LDA code if the sets I-r (F) = B-r (F) boolean AND C are distinct for all vertex subsets F subset of V (G) of size at most & ell; that share the same vertices in C. Similarly, Cis referred to as an (r, <= & ell;)-locating-dominating code of type B or (r, <= & ell;)-LDB code if the identifying sets I-r (F)are distinct for all vertex subsets F subset of V (G) \ C of size at most & ell;. In this article, we present optimal (with respect to density) (1, <= & ell;)-LDA and (1, <= & ell; + 1)-LDB codes in the infinite square grid for all & ell; >= 2. For (1, <= 2)-LDB codes in infinite square grid, we show that the optimal code will have density between [2/5, 11/5 ]. (c) 2026 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

The solubility of L-serine and L-isoleucine was investigated in pure water and in aqueous solutions of different molalities of sodium and potassium fluoride salts (NaF/KF), across a temperature range from 288.15 K to 308.15 K. Salting-in constants of 0.0784 and 0.07436 were obtained for KF + water and NaF + water systems, respectively, indicating an increase in solubility with higher electrolyte molality for L-serine. Conversely, salting-out constants of − 0.19424 and − 0.13592 were determined for NaF + water and KF + water systems, respectively, suggesting a decrease in solubility with increasing NaF or KF molality for L-isoleucine. The experimental solubility data were utilized to calculate transfer thermodynamic parameters related to solvation. By examining the solubility data and evaluating the thermodynamics associated with the free energetics of solvation, we gained insight into the solvation process and the weak interactions involved in the liquid phase of amino acids.