The complex permittivity spectra for the binary system maltitol‐water, within the frequency spectrum of 10 MHz 30 GHz have to been investigated employing the Time Domain Reflectometry (TDR). An analytical approach was undertaken to determine the static dielectric constant (ε0) and relaxation time (τ) corresponding to various volume fractions of water (Vwater) across various temperature conditions. These dielectric parameters were accurately fitted to the Cole–Davidson model to elucidate the relaxation dynamics. The Refractive Indices, Kirkwood Correlation Factor (KCF), Hydration number (Nhyd) and Thermodynamic parameters (∆H and ∆S) have been calculated thereby elucidating the intermolecular interactions present within the binary mixture. The observed increase in the dielectric constant coupled with a reduction in relaxation time, accompanying with an increase in the water content of the solution, suggests that these properties vary with solute concentration and temperature, shaped by the molecular structure of the solute. The empirically obtained static dielectric constants exhibit a strong correlation with the theoretical values, thereby substantiating the validity of the Alenka Luzar hydrogen-bonding model within this framework.
Conducting polymer polypyrrole (PPy) and its metal oxide composites, namely PPy-TiO₂ and PPy-SnO₂, were synthesized via in-situ chemical oxidative polymerization with 10% (w/v) metal oxide loading. To advance beyond conventional bi-composites, a new synergistic tri-composite sensor PPy-TiO₂-SnO₂ was developed through ex-situ mixing of the two binary composites. UV–Visible spectroscopy was employed to determine the optical band gaps, while SEM revealed granular, densely connected morphologies, further supported by elemental confirmation from EDX. FTIR analysis verified the interaction between PPy and the incorporated metal oxides, and TGA established the thermal sustainability of the composites for room-temperature sensing applications. Impedimetric analysis showed a linear 45° complex impedance behaviour and confirmed that AC conductivity decreases with increasing bandgap. All composite films were fabricated on glass substrates and evaluated for CO₂ sensing using a laboratory-developed sensing unit. Linear, dynamic, and static responses were recorded across varying CO₂ concentrations. The bi-composites displayed sensitivities of 3.43 (PPy-SnO₂) and 14.15 (PPy-TiO₂), whereas the newly synthesized PPy-TiO₂-SnO₂ exhibited an intermediate yet enhanced sensitivity of 8.09. The tri-composite also demonstrated rapid gas-sensing performance, with a short recovery time of 76 s and response time of 184 s. Energy-level alignment and Fermi-level pinning effects correlated well with the bandgap values, supporting the proposed sensing mechanism involving interfacial depletion and accumulation layers. Overall, the PPy-TiO₂-SnO₂ tri-composite emerges as a robust, sustainable, and efficient room-temperature CO₂ sensing material. The sensor also exhibits good selectivity towards CO₂ over interfering gases such as NH₃, ethanol, and CO. Furthermore, it demonstrates excellent long-term stability with a sensitivity drift of 6.10% over 35 days and minimal baseline variation. The sensor performance remains largely unaffected under varying humidity conditions (30–70% RH), indicating its suitability for practical environmental applications.
The Bisthiourea Nickel chloride (BTCC) single crystal and Mn2+ doped Bisthiourea Nickel chloride Mn-BTNC is grown by slow solvent evaporation method by using water as a solvent in a constant temperature bath. The grown crystals are used for powder X-ray diffraction (PXRD) which gives the structural analysis. Fourier Transform Infrared (FTIR) spectroscopy reveals the presence of functional groups in the grown crystal. The Energy Dispersive X-ray spectroscopy (EDX) confirms the doping of MnCl2 in the host BTNC crystal. The Scanning electron microscopy (SEM) gives the structural information of Pure BTNC and Mn doped BTNC single crystals. The Second Harmonic Generation (SHG) test is carried out to study the nonlinear optical (NLO) response of BTNC and Mn+2 doped BTNC single crystal with respect to KDP crystal.
Cayratia trifolia L. (fox grape) is a medicinal climber belonging family Vitaceae. to Traditionally it is used to treat fever, inflammation, skin disorders, and metabolic diseases, suggesting presence of phytochemicals. In addition, it possess antioxidant potential. Present study evaluates antioxidant potential of plant extracts. using standard in vitro methods. Antioxidant potential was assessed by the 1,1-diphenyl-2-picryl-hydrazyl (DPPH). Free-radical scavenging method is widely used to evaluate antioxidant activity. Antioxidant activity of the plants was assessed in comparison to that obtained with ascorbic acid. The results showed clear variations among the samples. The methanolic extracts exhibited highest radical scavenging activity meaning antioxidant potential.
Chemical etching is a simple and effective technique for evaluating surface defects and crystalline perfection in single crystals. In the present study, the etching behavior of pure and Y³⁺ doped L-threonine single crystals were investigated. The crystals were grown by the slow evaporation solution growth technique using distilled water as the solvent. A clear and well-developed crystal surface was carefully selected and polished for the etching experiment. Distilled water was employed as the etchant and the selected surfaces were exposed to the etchant for different durations. The etched surfaces were examined using a digital microscope to observe the formation, morphology and distribution of etch pits. The observed etch patterns provide information about growth related defects and surface imperfections present in the crystals. Etch-pit density was evaluated from the recorded microscopic images to compare the crystalline perfection of pure and Y³⁺ doped L-threonine crystals. The study demonstrates that chemical etching combined with digital microscopic observation provides a simple and useful approach for assessing defect distribution and crystalline quality in amino-acid based nonlinear optical crystals. These findings demonstrate that Y³⁺ incorporation improves the crystalline quality of L- threonine (LTH) and may be supports its potential for nonlinear optical applications.
