Madurai Kamaraj University

Ayyanusamy P., Venkatesan R., Rajan A.N., Annaraj J., Mahalingam U., Ramasamy P., Bethke K., Mayandi J.

Abstract Heavy metal ions (HMIs) detection in the aquatic, environmental and biological systems is of tremendous interest owing to their adverse effects on the ecosystem and human health, depending on the dose and its toxicity. The calorimetric sensor acts as a potential scavenger for detecting HMIs such as mercury, lead, copper, etc., which is reliable and more sensitive towards metal ions. In this work, chemically synthesized self-assembled cadmium sulfide quantum dots (CdS QDs) were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, UV-visible spectroscopy, transmission electron spectroscopy, energy dispersive X-ray spectroscopy which confirms the structural and morphological formation of QD and it act as a the DMSO@CdS QDs colorimetric sensing probe for the detection of copper, mercury and lead with the high selectivity and sensitivity with the limit of detection of 179.5 nM, 58 and 60 μM. The on-site detection is capable of monitoring heavy metals in environmentally polluted samples.

Mahalaxmi P., Balakrishnan K., Veerapandy V., Vajeeston N., Vajeeston P.

Fernandes de Almeida V., Navalón S., Dhakshinamoorthy A., Garcia H.

AbstractPhotocatalytic CO2 reduction to CH3OH, particularly with metal‐organic frameworks (MOFs) as photocatalysts, has garnered significant attention due to its long‐term potential to harness sunlight for converting CO2 into a valuable fuel and chemical feedstock. Numerous studies in the literature report the successful formation of CH3OH from photocatalytic CO2 reduction, sometimes supplemented with sacrificial agents, with claims substantiated by isotopic labelling measurements. However, in this Scientific Perspective, we note that much of the existing evidence has not been obtained under sufficiently rigorous experimental conditions to conclusively confirm the formation of a highly reactive product like CH3OH from the chemically stable CO2 molecule. This Scientific Perspective outlines best practices designed to provide robust evidence for CH3OH formation in photocatalytic processes, which could be instrumental in clarifying the state‐of‐the‐art and accelerating the development of this technology toward practical applications.

Fernandes de Almeida V., Navalón S., Dhakshinamoorthy A., Garcia H.

AbstractPhotocatalytic CO2 reduction to CH3OH, particularly with metal‐organic frameworks (MOFs) as photocatalysts, has garnered significant attention due to its long‐term potential to harness sunlight for converting CO2 into a valuable fuel and chemical feedstock. Numerous studies in the literature report the successful formation of CH3OH from photocatalytic CO2 reduction, sometimes supplemented with sacrificial agents, with claims substantiated by isotopic labelling measurements. However, in this Scientific Perspective, we note that much of the existing evidence has not been obtained under sufficiently rigorous experimental conditions to conclusively confirm the formation of a highly reactive product like CH3OH from the chemically stable CO2 molecule. This Scientific Perspective outlines best practices designed to provide robust evidence for CH3OH formation in photocatalytic processes, which could be instrumental in clarifying the state‐of‐the‐art and accelerating the development of this technology toward practical applications.

Iniya L., Sivakumar B.

This paper treats a continuous review stochastic inventory system with retrial demands. We assume that demand time points form a Poisson process. The demands which occur during stock out period enter an orbit of infinite size. These orbiting demands retry for their demand after a random time, which is assumed to be exponential distribution. We assume constant retrial policy for the orbiting demands. The inventory is replenished by an outside supplier with flexible reorder point. The lead times for the order is exponential distribution. Formulating this model as a Markov decision problem, we characterize the optimal replenishment policy as a monotonic threshold function of reorder point under the discounted cost criterion. We present some numerical examples to illustrate the result.

Parvathy M.R., Manonmani I.K.

The concept of liveability, rooted in ancient philosophy and evolving through urban research, lacks a singular definition but emphasizes the quality of life in urban environments. This study examines the effectiveness of the Liveability Index introduced by the Ministry of Urban Development, Government of India, in discerning spatial disparities in liveability within Madurai City, Tamil Nadu. Utilizing secondary data from various sources, including the Corporation of Madurai City, the study evaluates 49 indicators categorized into four pillars: Institutional, Social, Economic, and Physical. Through a detailed spatial analysis, the study identifies areas characterized by higher and lower levels of liveability, providing insights into the factors contributing to disparities. The findings reveal that liveability in Madurai is notably high in core wards, with some peripheral wards also exhibiting favourable scores. The primary pillars determining liveability are identified as Physical and Social, with Governance presenting exceptions. However, discrepancies in the Economic Index highlight the need for additional indicators for a comprehensive assessment. The study underscores the importance of the Liveability Index in facilitating city-to-city comparisons and identifying areas for improvement, thereby enhancing urban planning and policy interventions.

Rana A., Mukherjee S., Abirami Sundari K., Dhakshinamoorthy A., Biswas S.

AbstractSelective chemical fixation of carbon dioxide (CO₂) offers a promising approach to mitigate rising atmospheric CO₂ levels while facilitating the synthesis of valuable commodity chemicals, thereby supporting the circular economy. The cycloaddition of CO₂ to form α‐alkylidene cyclic carbonates is particularly attractive due to its utilization of CO₂, a low‐cost C1 feedstock, in a reaction with 100% atom economy. In this study, we have developed an amine‐functionalized, nitrogen‐rich covalent organic polymer (COP), SNW‐1@NH₂, which strongly supports the grafting of Cu(I) ions within its porous framework. The synergistic interaction between SNW‐1@NH₂ and Cu(I) enhances the catalytic activity for the CO₂ cycloaddition with propargylic alcohol, resulting in the formation of α‐alkylidene cyclic carbonates at room temperature without the need for precious metal catalysts. Notably, the catalyst exhibits a broad substrate scope with high recyclability and maintains its structural integrity and catalytic performance. Additionally, the SNW‐1@NH₂ was successfully applied in the catalytic Knoevenagel condensation of benzaldehyde with cyanoacetamide, demonstrating a broad substrate scope, excellent recyclability, and stability. Mechanistic studies were performed to elucidate the reaction pathways for both catalytic processes. This work underscores the potential of nitrogen‐rich porous materials in addressing the critical environmental challenges and expanding catalytic applications.

Govindharaj P., Kannan J., Shanmugam S., Data P.

AbstractThe advancement of organic room temperature phosphorescence (RTP) materials has attracted considerable interest owing to their extensive applications. Their distinct advantages, including a metal‐free composition, low toxicity, and facile synthesis under ambient conditions, make them highly desirable. This study examines the delayed fluorescence (DF) and RTP of metal‐free, amorphous indenophenanthridine (IND)‐based derivatives (1–10) and provides insights into molecular functionalisation and host matrix effects on delayed emission (RTP and DF). IND derivatives have been used in bioimaging and organic analyte detections; however, their delayed emission mechanism photophysical processes are poorly understood. This work examines the derivatives’ physicochemical properties and time‐resolved photophysics to determine how molecular structure, host interaction, and delayed emission properties relate. The described IND compounds show RTP and/or TTA (triplet‐triplet annihilation) delayed fluorescence depending on the host environment. This research lays the groundwork for designing and developing new materials with increased RTP efficiency for future applications by detailing the detailed RTP processes and the crucial function of the host matrix.

Devarajan N., Saravanakumar N., Suresh P.

ABSTRACTThe catalytic efficacy of the Lewis acidic site in Cu3(BTC)2 MOF was compared with the Brønsted acidic site in MIL‐101‐SO3H MOF. Both Lewis and Brønsted acidic MOFs demonstrate strong conversion rates in the synthesis of 2,4,5‐triaryl imidazoles through a one‐pot multicomponent reaction under a microwave condition. This outcome underscores the stability and reusability of both MOFs. The catalytic activity of the MOFs relies on the facile accessibility of catalytically active centers/sites to the reactants. Superior results were achieved with MIL‐101‐SO3H MOF's Brønsted acidic sites compared with Cu3(BTC)2 MOF's Lewis acidic sites due to the latter's shortcomings in reusability and stability as a catalyst in the synthesis of 2,4,5‐TSIs (2,4,5‐trisubstituted imidazoles). MIL‐101‐SO3H MOF can be reused multiple times without any loss in its catalytic activity, as demonstrated by hot filtration tests and various analytical techniques such as FTIR, powder XRD, SEM, and EDAX conducted on both fresh and reused MOF catalysts.

Arunesh K., Rajeashwari S.

DFU (Diabetes Foot Ulcer) is caused in the foot of diabetes patients and if the disease is not diagnosed within time, it may lead to various complications and severities. The major symptoms of DFU are foot swelling, dry cracks, leg pain, varied temperature of skin and changes in skin color. When DFU is not treated properly complications tends to remove limb or foot of a person. To overcome these limitations, automatic methods are required for detecting and classifying healthy skin and DFU images. However, the classification of DFU from existing researches provides challenges like resemblance between healthy skin and DFU and has high intra-class and inter-class variations in accordance with the lighting conditions and patient’s ethnicity. The collection and labelling of DFU requires large time and it is complex to differentiate a DFU and a healthy skin, for instance when there are images with a toe, skin wrinkles and small sizes of DFU. Hence, the proposed system implemented DCNN (Deep Convolutional Neural Network) based Xception model, to involve binary classification of healthy and DFU skin images. The DCNN is employed to handle large dataset, but produces over-fitting issues. So, the proposed DCNN based Xception classifier is integrated with RLCL (Residual Linearly Clamped Layers) consisting of minimum detached convolution layers. It helps in reducing over-fitting problems and thus increases precision and computational speed of the proposed system. Further, the input images are optimized by using image enhancement techniques such as Histogram equalization, Adaptive filter and Gamma correlation. Then the efficiency of the proposed system is evaluated based on the performance metrics namely precision, F1-score, recall and accuracy to validate the performance of proposed model with existing algorithms.

Ponraj A., Vaganan B.M.

A new generalized Fisher–Kolmogorov–Petrovskii–Piskunov equation [Formula: see text] is introduced and subjected to Lie’s Classical Method to establish the existence of the traveling waves. Indeed, exact expressions for both the solution [Formula: see text], with [Formula: see text] and the wave speed [Formula: see text] are subsequently derived by the regular perturbation method and are shown to contain both the reports of Ablowitz and Zeppetella [Explicit solutions of fisher’s equation for a special wave speed, Bulletin of Mathematical Biology 41(6) (1979) 835–840] when [Formula: see text] and Kaliappan [An exact solution for the traveling waves of [Formula: see text], Physica D: Nonlinear Phenomena 11(3) (1984) 368–374] when [Formula: see text], respectively. Remarkably, the generalized Huxley equation is a special case of our model equation. The form of the traveling waves for the Fisher–Kolmogorov–Petrovskii–Piskunov equations is identified with the regular perturbation method and the Binomial series. Our study is in agreement with the conclusion of Fisher [The wave of advance of advantageous genes, Annals of Eugenics 7(4) (1937) 355–369] that the increase of frequency of mutant genes results in the diffusion of the mutant genes into the long range.

Pushpa Selvi M., Motsei T., Tshabalala K., Ocaya R., Suja S.K., Soosaimanickam C., Nimma Elizabeth R.

Srinivasan P., Sivaruban T., Sruthi S.P., Barathy S., Isack R., Nadar M.S.

Maga R., Anitha K., Jayalakshmi D.

A novel single crystal of p-Toluidine cadmium chloride was examined by X-ray diffraction analysis which revealed the structural data, cell parameters and crystal system. The PTCC crystal is grown in the 1:1 ratio by slow evaporation solution growth technique. The UV–visible spectrum analysis observed the optical quality of the crystal in the range of 200 nm to 1000 nm. The grown crystal shows a good transmittance range. The identification of various functional groups of PTCC crystal was analysed by Fourier Transform Infrared Spectroscopy. The photoconductivity study analysed the grown PTCC crystal has a photoconductivity nature. The dielectric constant and dielectric loss are measured as a function of frequency used to determine the electrical properties. The thermal analysis of both thermogravimetric and differential thermal study measures a material is stable up to 150 °C. The third-order nonlinear susceptibility (χ3) is calculated by the z-scan technique whose wavelength is 632.8 nm using a source of He–Ne laser.

M. M.B., M.V. L.C., S. S., S. A.H., N. M.V.

Solid biomaterial electrolytes have been prepared by using Centella asiatica (CA) as biomaterial with various compositions of magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) salt by solution casting technique using double-distilled water as solvent. Surface morphological studies for pure and highest conducting membranes have been obtained by SEM analysis. The amorphous nature and crystalline percentage of the biomaterial electrolyte have been studied by X-ray diffraction analysis. The glass transition temperature of the pure and the prepared biomaterial electrolyte membranes have been determined by differential scanning calorimetric analysis. Thermal stability of pure and highest conducting membranes is studied by TGA analysis. Electrical conductivity of the biomaterial electrolyte is measured by AC impedance analysis, and the dielectric behavior of the biomaterial electrolyte is also analyzed. The maximum magnesium ionic conductivity of biomaterial membrane is [1.14 ± (0.07)] × 10−2 S/cm for 1 g CA + 0.5 M wt% Mg(NO3)2·6H2O at room temperature. Transference number measurements are calculated from Wagner’s and Evan’s DC polarization techniques. The electrochemical stability window for biomaterial membrane with maximum magnesium ionic conductivity is 3.26 V, obtained by linear sweep voltammetry technique. The electrochemical reversibility is studied by cyclic voltammetry technique for 101 cycles. The primary Mg-ion battery is constructed with maximum magnesium ionic conductivity membrane as electrolyte, magnesium metal of diameter 12 mm and thickness 1 mm as anode and MoS2 as cathode. Open-circuit voltage (OCV) of the constructed Mg-ion primary battery is 1.92 V. The performance of the primary Mg-ion battery is evaluated with different loads.