AMET University

MgFe1.9X0.1O4 (X = Bi, Cu, Nd, Ni) spinel ferrites have been prepared by a combustion process and their structural, optical, and magnetic characteristics have been studied in detail. X-ray diffraction (XRD) and Rietveld refinement established the single-phase cubic spinel structure (Fd-3 m) with the lattice parameters within the range of 8.3843–8.4051 Å, and the FTIR analysis confirmed the occurrence of typical Fe–O and M–O vibrational modes which determined the formation of spinel ferrites. The existence of a tunable band gap between 1.74 and 1.85 eV was observed through optical analysis, and the optical conductivity at the visible and near-infrared spectrum was increased by defect states introduced by the dopant and charge carrier generation. The visible emission in photoluminescence (PL) spectra were found to have an intensity and wavelength change based on the dopant, and enabled by CIE chromaticity analysis, showed tunable emission properties. Magnetic measurements have shown that the incorporation of dopants has a significant effect on the magnetic behavior, where the saturation magnetization is up to 0.338 emu g−1 and the coercivity is between 127 and 155 Oe. The observed changes can be explained by the cation redistribution and altered super exchange interactions. The findings in general indicate that using controlled incorporation of dopants allows optical and magnetic characteristics to be tuned in tandem, and thus the capacity of MgFe1.9X0.1O4 ferrites to possess multiple functionalities. The materials have the potential to be used in optoelectronic, sensing, and spintronic systems.

Abstract India’s marine biodiversity remains unevenly documented, with fragmented and inconsistently accessible observations limiting their use for long-term assessment and conservation planning. To address this gap, we developed OceanEyes, a citizen-science mobile application designed for standardised, high-resolution documentation of marine biodiversity across India’s EEZ. The platform integrates Darwin Core-compliant data structures with a two-tier expert validation system, ensuring scientific accuracy and interoperability with global repositories. Unlike existing platforms, OceanEyes is specifically tailored to marine ecosystems, incorporating domain-specific metadata (e.g., habitat, depth, substrate) and enabling offline data collection in low-connectivity coastal regions. A comparative analysis demonstrates that OceanEyes bridges the gap between global generalist platforms and region-specific applications by combining marine focus, standardisation, expert validation, and integration with OBIS via IndOBIS through standardised data export. Initial deployment (November 2023–March 2026) recorded 539 users, with ~ 74% from India, and peak engagement of 232 active users, stabilising at 60–100 users, indicating sustained participation. These results demonstrate the platform’s usability and scalability for participatory marine monitoring. By combining citizen participation with rigorous quality control and FAIR-compliant data workflows, OceanEyes provides a scalable and scientifically robust framework for marine biodiversity documentation, with direct relevance to marine spatial planning and national commitments under the Convention on Biological Diversity and SDG 14.

This study aims to develop a sustainable multi-fuel strategy for diesel engines by examining the combustion, performance, and emission characteristics of industrial chicken-fat biodiesel (B100) enriched with 2-ethyl-1-hex-anol (2-EH) and supplemented with ammonia (NH3) fumigation. The objective is to overcome limitations of neat biodiesel, such as high viscosity, low volatility, and incomplete combustion, while enhancing overall engine efficiency. Five test fuels (D100, B100, 2-EH5 %B100 +NH3 5lpm, 2-EH10 %B100 +NH3 5lpm, 2-EH15 % B100 +NH3 5lpm) were evaluated in a single-cylinder diesel engine operating at 1500 rpm under five brake-load conditions (0-100 %). Combustion parameters, performance metrics and emissions were measured. NH3 fumigation was supplied at 5 lpm using a controlled intake-manifold system. Combustion analysis demonstrated that B100 exhibited weaker premixed combustion than D100, as evidenced by lower in-cylinder pressure and heat-release rate (HRR) peaks. Under full load conditions, the blend 2-EH15 %B100 +NH3 5lpm achieved the greatest combustion, with in-cylinder pressure around 48.05 % higher than B100 and 3.22 % higher than D100. The maximum HRR was nearly 70 % greater than B100 and about 6.7 % higher than D100, indicating intensified premixed heat release near top dead centre. Brake thermal efficiency (BTE) increased by 14.8 % compared with B100 and 3.7 % over diesel, while brake specific energy consumption (BSEC) decreased by 28.7 % relative to B100. Significant emissions reductions in carbon monoxide (CO) by 37.5 %, hydrocarbon (HC) by 11.1 %, and smoke opacity by 35.3 % were observed compared with B100. However, oxides of nitrogen (NOx) emissions increased by 33.1 %, attributed to enhanced premixed combustion and higher in-cylinder temperatures. The synergistic combination of waste-derived biodiesel, higher alcohol, and NH3 fumigation enhances combustion phasing, improves thermal efficiency, and substantially lowers major pollutants except NOx. Although the strategy introduces a NOx penalty, it demonstrates strong potential for cleaner, more efficient diesel-engine operation and may be further optimized through future NOx mitigation technologies.

Using commercial materials for colorimetric detection of toxic cyanide (CN-) anions can greatly improve safety and benefit society. This work discusses the colorimetric sensing properties of commercially available trans-(3-nitrostyrene analogues, including trans-(3-nitrostyrene (P1), trans-4-methoxy-(3-nitrostyrene (P2), trans-4-methyl-(3-nitrostyrene (P3), trans-4-fluoro-(3-nitrostyrene (P4), trans-4-bromo-(3-nitrostyrene (P5), trans-4-chloro-(3-nitrostyrene (P6), and trans-(3-methyl-(3-nitrostyrene (P7), in dimethyl sulfoxide (DMSO) and acetonitrile (ACN). P1-P4 show strong reddish-pink and yellowish-orange colors while detecting CN-ions in DMSO and ACN, with new UV-visible peaks appearing at 515 nm/510 nm and at 490 nm/485 nm, respectively. Conversely, P5 and P6 exhibit mild color responses to CN-in DMSO and ACN, with absorbance peaks at 505 nm/510 nm and at 490 nm/430 nm, respectively. P7 shows no selectivity for CN-ions due to steric and electronic structural effects. The high selectivity of P1-P4 for CN-is confirmed through interference studies. pH values of 6 and 7 are ideal for sensory testing. The sensor response of P1-P6 to CN-is linear across a range of 0.1 to 1000 mu M (mu M = 10-6 M), with estimated detection limits (LODs) at 10-9-10-6 M. Nuclear Magnetic Resonance (NMR), mass spectra, and density functional theory (DFT) analyses validate the Michael addition as the sensing mechanism. The test strip method demonstrates the solid-state colorimetric sensing ability of P1-P3 for CN-ions. Spiked CN-ions in water samples show the real-time sensing capability of P1-P4. These results open the door for future designs using different fluorophores with nitro (-NO2) Michael acceptor.

The study presents the successful synthesis and crystallization of a square pyramidal copper(II) complex coordinated with glycine in its zwitterionic form [CuS_2(C_4H_10N_2O_4)]_2(C_2H_5NO_2)_2 (1), as confirmed by single crystal XRD study. The complex crystallizes in an orthorhombic system with space group Pna2_1 , exhibiting a tetracoordinated copper center bound to oxygen and sulfur atoms in a cis-square planar geometry. The crystal structure is stabilized by a comprehensive grid of hydrogen bonds involving N–H ⋯ O and N–H ⋯ S interactions, which form characteristic graph-set motifs and contribute to a three-dimensional zig-zag molecular packing. FTIR confirmed glycine coordination and Cu–N/Cu–S bonding. Thermogravimetric analysis reveals that the title compound is thermally stable up to 86 ^∘C , adequate for room-temperature lasing applications, and its subsequent decomposition further supports the elemental composition of the material. UV–Visible spectra showed a strong peak at 208 nm, an absorption edge at 237 nm, and a wide band gap of 5.55 eV, indicating high electronic stability. Photoluminescence revealed broad emission from 370 to 532 nm, deconvoluted into ligand-centered, ligand-to-metal, and metal-centered transitions, demonstrating efficient energy redistribution within the complex. Glycine, in its zwitterionic form, acts as a bidentate ligand coordinating with transition metals to form complexes exhibiting nonlinear optical behavior, including nonlinear absorption, refraction, and excited-state transitions through metal-ligand charge transfer. The nonlinear optical studies by Z-scan revealed self-defocusing behavior and efficient optical limiting. The measured nonlinear refractive index n_2 was 2.786× 10^-8 cm^2 W^-1 , and the nonlinear absorption coefficient β was 0.92× 10^-4 cm W^-1 . The third-order nonlinear optical susceptibility χ ^(3) was found to be 2.46× 10^-6 esu, demonstrating significant third-order nonlinear response. Optical limiting measurements showed an onset threshold of 1.545× 10^3 W cm^-2 proving the material’s ability to shield optical devices from high-intensity light.