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Interpenetrated Robust Metal-Organic Framework with Urea-Functionality-Decked Pores for Selective and Ultrasensitive Detection of Antibiotics and Oxo-anions
Conjoining the benefits of structural diversity and deliberate implantation of task-specific sites inside the porous channels, metal-organic frameworks (MOFs) not only ensure environmental remediation via acute detection of organic as well as inorganic pollutants but also rationalize structure-performance synergies to devise smarter materials with advanced performances. Herein, we report a urea-functionality-grafted Co(II)-framework (UMOF) based on a mixed ligand approach. The 3-fold interpenetrated and [Co2(COO)4N4] building unit-containing structure exhibits high stability and free-carboxamide-site-decorated microporous channels. Assimilation of high-density hydrogen-bond donor groups plus the ?-electron-rich aromatic ligand benefits the UMOF acting as a selective fluoro-sensor for three noxious antibiotics through remarkable quenching, including nitrofurazone (NFT, Ksv: 3.2 104 M-1), nitrofurantoin (NFZ, Ksv: 3.0 104 M-1), and sulfamethazine (SMZ, Ksv: 3.3 104 M-1) with ppb level limits of detection (LODs, NFT: 110.42, NFZ: 97.89, and SMZ: 78.77). The mechanistic insight of luminescence quenching is supported from density functional theory calculations, which endorse the electron-transfer route via portraying variation in the energy levels of the urea group-affixed linker by individual organo-toxins, besides verifying analyte-linker noncovalent interactions. The framework further demonstrates highly discriminative turn-off detection of oxo-anions with extreme low LODs (Cr2O72-: 73.35; CrO42-: 189; and MnO4-: 49.96 ppb). Of note is the reusability of the UMOF toward multicyclic sensing of all the organic and inorganic analytes besides their fast-responsive detection, where variable magnitudes of energy-transfer contributions unequivocally authenticate the turn-off event. 2023 American Chemical Society. -
Synthesis and characterization of biowaste-based porous carbon nanoparticle-polymer dispersed ferroelectric liquid crystal composites
Herein, porous carbon nanoparticles (PCNPs) were synthesized using magnolia champaca seed pods and studied their doping effect on the polymer-dispersed ferroelectric liquid crystal (PDFLC) properties. The effect of PCNPs concentration (?0.75 wt.%) on the morphology of PDFLC, polarization, and permittivity are investigated in thin sample cells. Field emission scanning electron microscope image results indicate the spherical shape of PCNPs of particle size ?27 nm diameter. Temperature-dependent electro-optic and dielectric properties are also investigated in the wide SmC* phase and near transition temperature of SmC*-SmA*. Polarising optical microscope textures confirm the non-homogeneity of FLC molecules in the polymer matrix as a function of PCNPs concentration. The spontaneous polarization and anchoring energy coefficients increase with increasing the doping amount of PCNPs. The phase transition temperature is found unaffected by PCNP doping in all prepared samples. In PDFLC and PCNPs doped PDFLC composites, usual behaviour of permittivity as a function of temperature is observed. Fluorescence spectra show an enhanced two-fold increase in emission intensity peak at 412 nm wavelength for 0.5 wt.% PCNPs doped PDFLC while concentration-dependent quenching and slight redshift have been observed for the 0.75 wt.% PCNPs doped PDFLC. The enhanced electro-optic and dielectric properties observed in the composites suggest potential applications in displays, sensors, and optical devices. The findings open doors for further exploration and utilization of these functional materials in advanced electronic and photonic technologies. 2023 Elsevier B.V. -
Effects of a Mindfulness-based Intervention on Well-being Among Rural Adolescents with Academic Anxiety
Background: Academic anxiety revolves around scholastic work and performance and can be detrimental to students health and overall subjective well-being. It has been found to be significantly high in adolescents, leading to consequences that prove to be detrimental to their academic performance, focus, and overall self-esteem. This phenomenon acts as a vicious cycle impacting all aspects of a students life. Method: The current study aimed to explore mindfulness-based intervention (MBI) as a possible option to deal with academic anxiety in rural adolescent students and improve their overall subjective well-being. A total of 600 students were screened for academic anxiety and a total of 47 students were subjected to an eight-week MBI. MBI aims to bring more present-moment awareness and cultivate overall well-being and thereby works against anxiety. Mixed repeated measures ANOVA was carried out to compare pre, post, and follow-up scores. Result: The results indicated a significant effect of MBI on adolescents, suggesting a significant decline in academic anxiety from pre-to-post and an increase in mindfulness and subjective well-being from pre-to-post and follow-up assessments. Conclusion: Academic anxiety and subjective well-being improved significantly with the MBI intervention, thereby implication that MBI is a feasible option for rural adolescents with academic anxiety. 2024 The Author(s). -
Polypyrrole/ silver/graphene ternary nanocomposite synthesis and study on photocatalytic property in degrading Congo red dye under visible light
In this report, a simple chemical synthesis of polypyrrole/silver/graphene (Ppy/Ag/Gr) ternary nanocomposites with varying concentrations of graphene are described. The XRD spectra of the samples polypyrrole/silver (Ppy/Ag) and Ppy/Ag/Gr show all the peaks of the face-centered cubic structure of silver. A broad peak between 10 and 20 and a peak at 26.7 corresponds to Ppy and graphene respectively. Using FTIR, and UVVis. spectroscopies the interaction between polypyrrole, silver, and graphene were studied. In our work, we explored the photocatalytic property of the synthesised samples by using them to degrade the aqueous solution of a cancer-causing dye, Congo red. The percentage degradation of Congo red dye using the sample Ppy/Ag/Gr (0.5 wt.%) is obtained as 96% and the reaction rate calculated is 0.162/min., greater than that of Ppy/Ag and Ppy/Gr binary composites. Thus, the addition of the optimum concentration of graphene into Ppy/Ag enhanced its photocatalytic property. The BET analysis shows an increased surface area for the sample Ppy/Ag/Gr (0.5 wt.%) and the reason for the enhancement of photocatalysis with this sample is confirmed since it is a surface-dependent property. The biodegradability of the dye solution was investigated by Chemical Oxygen Demand (COD) analysis and the COD value was reduced from 432 mg/L to 216 mg/L after 20 min of irradiation of light. 2023 -
A Facile One-Pot Solvent-Free Synthesis, in Vitro and in Silico Studies of a Series of Tetrahydropyridine Derivatives as Breast Cancer Inhibitors
Ammonium trifluoroacetate (ATA) catalysed synthesis of 1,2,5,6-tetrahydropyridine (THP) derivatives, under eco-friendly conditions via a facile one-pot strategy. We have synthesized fifteen THP derivatives, and docked into the crystal structure of Phosphatase and Tensin Homolog deleted on Chromosome 10 (PTEN) tumour suppressor protein (PDB ID: 1D5R) based on drug-likeness prediction and pharmacokinetic properties. Molecular docking simulation studies reveal that four of our synthesised compounds are potential hit candidates because they bound to the receptor through 57 conventional hydrogen bonds with ?9.7 to ?8.6 kcal/mol of binding energy. The compounds were evaluated using the in vitro inhibitory activity of MCF-7 breast cancer cell lines. Identified hit compounds showed moderate inhibition at (160320 ?g/mL) and inhibitory concentration IC50 values in the low micromolar range of 171.062, 189.803, 195.469 and 181.272 ?g/mL respectively. The results obtained are very promising; therefore fine-tuning the substituents of hit molecules with appropriate bioisosteres can lead to the development of potential leads. 2023 Wiley-VCH GmbH. -
Insights into the plant growth promotion properties of bacterial endophytes isolated from Alternanthera philoxeroides and Eichhornia crassipes from Bellandur lake, India
The presence of macrophytes such as Alternanthera philoxeroides and Eichhornia crassipes in Bellandur Lake, India, has been observed despite the high pollution levels. Our research aims to explore the potential role of endophytes in promoting the growth of these macrophytes in such heavily contaminated environments. In current study, we isolated 20 endophytic bacteria from various parts of A. philoxeroides (12) and E. crassipes (8) plants, including shoots, roots, leaves, and flowers. We found that a significant proportion of endophytes from A. philoxeroides (42 %) and E. crassipes (25 %) produced more than 100 g/mL of indole acetic acid (IAA). Similarly, the majority of the isolates possessed other plant growth promoting traits like ammonia production, nitrogen fixation, phosphate and potassium solubilization, siderophore production, and ACC deaminase production. Many of these isolates demonstrated extracellular enzyme production and halotolerance properties. We identified Acinetobacter soli ON529869 and Bacillus licheniformis ON506048 as the most effective plant growth promoters among the isolates, which also displayed antifungal properties against Fusarium solani and Cladosporium tenuissimum in vitro. Furthermore, greenhouse trials using these two endophytes revealed their significant plant growth promotion abilities in Amaranthus viridis. The pigment indices were evaluated using CI-710 Leaf Spectrometer. In conclusion, our findings provide compelling evidence for exploring the endophytic microbiomes of macrophytes in polluted areas for sustainable agriculture and bioprospecting of unique traits. This research could lead to the discovery of new and valuable resources for agricultural practices and other applications. 2023 SAAB -
Performance investigations of five-level reduced switches count ?-bridge multilevel inverter
Introduction. This research paper describes a simple five-level single-phase pulse-width modulated inverter topology for photovoltaic grid applications. Multilevel inverters, as opposed to conventional two-level inverters, include more than two levels of voltage while using multiple power switches and lower-level DC voltage levels as input to produce high power, easier, and less modified oscillating voltage. The H-bridge multilevel inverter seems to have a relatively simple circuit design, needs minimal power switching elements, and provides higher efficiency among various types of topologies for multi-level inverters that are presently accessible. Nevertheless, using more than one DC source for more than three voltage levels and switching and conduction losses, which primarily arise in major power switches, continue to be a barrier. The novelty of the proposed work consists of compact modular inverter configuration to connect a photovoltaic system to the grid with fewer switches. Purpose. The proposed system aims to decrease the number of switches, overall harmonic distortions, and power loss. By producing distortion-free sinusoidal output voltage as the level count rises while lowering power losses, the constituted optimizes power quality without the need for passive filters. Methods. The proposed topology is implemented in MATLAB/Simulink with gating pulses and various pulse width modulation technique. Results. With conventional topology, total harmonic distortion, power switches, output voltage, current, power losses, and the number of DC sources are investigated. Practical value. The proposed topology has proven to be extremely useful for deploying photovoltaic-based stand-alone multilevel inverters in grid applications. References 18, table 2, figures 15. 2023, National Technical University "Kharkiv Polytechnic Institute". All rights reserved. -
Blocking intrusion logic using optimized multi-head convolution in wireless sensor network
Wireless sensor nodes (WSN) combine sensing and communication capabilities in the smallest sensor network component. Sensor nodes have basic networking capabilities, such as wireless connection with other nodes, data storage, and a microcontroller to do basic processing. The intrusion detection problem is well analyzed and there exist numerous techniques to solve this issue but suffer will poor intrusion detection accuracy and a higher false alarm ratio. To overcome this challenge, a novel Intrusion Detection via Salp Swarm Optimization based Deep Learning Algorithm (ID-SODA) has been proposed which classifies intrusion node and non-intrusion node. The proposed ID-SODA technique uses the k-means clustering algorithm to perform clustering. The Salp Swarm Optimization (SSO) technique takes into residual energy, distance, and cost while choosing the cluster head selection (CHS). The CHS is given the input to a multi-head convolutional neural network (MHCNN), which will classify into intrusion node and non-intrusion node. The performance analysis of the suggested ID-SODA is evaluated based on the parameters like accuracy, precision, F1 score, detection rate, recall, false alarm rate, and false negative rate. The suggested ID-SODA achieves an accuracy range of 98.95%. The result shows that the suggested ID-SODA improves the overall accuracy better than 6.56%, 2.94%, and 2.95% in SMOTE, SLGBM, and GWOSVM-IDS respectively. 2023 - IOS Press. All rights reserved. -
Vertex neighborhood restricted edge achromatic sums of graphs
The vertex induced 2-edge coloring number ?vi2?(G) of a graph G is the highest number of colors that can occur in an edge coloring of a graph G such that not more than two colors can be used to color the edges in the induced subgraph (N[v]) generated by the closed neighborhood N[v] of a vertex v in V (G). The vertex induced 2-edge coloring sum of a graph G denoted as vi2?(G), is the greatest sum among all the vertex induced 2-edge coloring of a graph G which concedes ?vi2?(G) colors. The vertex incident 2-edge coloring number of a graph G is the highest number of colors required to color the edges of a graph G such that not more than two colors can be ceded to the edges incident at the vertex v of G. The vertex incident 2-edge coloring sum of a graph G denoted as vi2?(G), is the maximum sum among all the vertex incident 2-edge coloring of graph G which receives maximum ?vin2?(G) colors. In this paper, we initiate a study on the vertex induced 2-edge coloring sum and vertex incident 2-edge coloring sum concepts and apply the same to some graph classes. Besides finding the exact values of these parameters, we also obtain some bounds and a few comparative results. 2023 World Scientific Publishing Company. -
Solvent-solute interaction, thermodynamic behaviour, structural, chemical and anti-cancer biological properties of 3(2H)-furanone derivatives
In this work, the structures, reactivities, and electronic and biological properties of the 3(2H)-furanone derivatives, 2-hydroxy-2,5-diphenyl-4-(phenylamino)furan-3(2H)-one (HDPF), 2-methoxy-2,4,5-triphenylfuran-3(2H)-one (MTPF), 3-oxo-2,4,5-triphenyl-2,3-dihydrofuran-2-yl acetate (OTDF), and 2-chloro-2,4,5-triphenylfuran-3(2H)-one (CTPF), are explored via theoretical investigations using DFT (Density Functional Theory) techniques as the main tools for the study. The DFT studies include geometry optimisation, FMO (Frontier Molecular Orbital) analysis, theoretical UV studies, molecular electrostatic potential (MEP) investigations, non-linear optical (NLO) analyses, and the evaluation of thermodynamic parameters. Multiwfn 3.8 software is utilised to conduct the topological analyses. The ADME (Absorption, Distribution, Metabolism, Excretion) profiles are produced with the SwissADME online tool. The target proteins, MCL-1 (Myeloid cell leukemia-1), BCL-2 (B-cell lymphoma-2), and myeloblastin, are docked with the title molecules using AutoDock 1.5.6. 2023 Elsevier B.V. -
Plant Leaf Disease Classification Using Optimal Tuned Hybrid LSTM-CNN Model
Tomatoes are widely cultivated and consumed worldwide and are susceptible to various leaf diseases during their growth. Therefore, early detection and prediction of leaf diseases in tomato crops are crucial. Farmers can take proactive measures to prevent the spread and minimize the impact on crop yield and quality by identifying leaf diseases in their early stages. Several Machine Learning (ML) and Deep Learning (DL) frameworks have been developed recently to identify leaf diseases. This research presents an efficient deep-learning approach based on a hybrid classifier by optimizing the CNN and LSTM models, which helps to enhance classification accuracy. Initially, Median Filtering (MF) is used for leaf image pre-processing. Then, an improved watershed approach is used for segmenting the leaf images. Subsequently, enhanced Local Gabor Pattern (LGP) and statistical and color features are extracted. An optimized CNN and LSTM are used for classification, and the weights are tuned using the SISS-OB (Self Improved Shark Smell With Opposition Behavior) algorithm. Finally, we have analyzed the performance using various measures. Since we have done segmentation, feature extraction, and optimization improvisations, our proposed methodology results are higher than other available methods and existing works. The results obtained at Learning Percentage (LP) is 90% which is far superior to those obtained at other LPs. The FNR (False Negative Rate) is much lower (0.05) at the 90th LP. The proposed model achieved better classification performance in terms of Accuracy of 97.13%, Sensitivity of 95.09%, Specificity of 95.24%, Precision of 94.31%, F measure of 96.71% and MCC 87.34%. 2023, The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. -
Enhanced supercapacitors and LPG sensing performance of reduced graphene oxide/cobalt chromate pigments for energy storage applications
It is imperative that an initial inquiry be conducted as soon as possible since the production of monolayer of carbon atoms (rGO) composites is the root cause of their poor performance in supercapacitor and LPG sensors. Here, an effort is undertaken to construct a cobalt chromate pigments-reduced graphene oxide (CoCr2O4/rGO) by solution combustion method for the supercapacitor and LPG sensor. The proposed method is efficient and easy in terms of its application to the production of CoCr2O4/rGO polycrystalline composite on a wide scale. Within the scope of this work is an investigation into the improved supercapacitor and LPG sensing behaviour of CoCr2O4/rGO polycrystalline composite. We have implemented a simple method that has been identified for mass-producing reduced graphene oxide. The Solution combustion technique was used, and it was successful in achieving this goal for the very first time. X-ray diffraction technique is used analyse crystallinity, phase, and structural investigation. The nature of gas sensing behaviour with a step function of LPG gas at 500 ppb was studied at room temperature for rGO, The CoCr2O4 pigments and 0.5CoCr2O4+0.5rGo polycrystalline composite samples. The gas response is maximum for 0.5CoCr2O4+0.5rGo polycrystalline composite in the order of 97% in compare with the reduced graphene oxide sample which shows the lowest sensitivity in the order of 26% on exposure of liquified petroleum gas (LPG). The recorded response and recovery times of 0.5CoCr2O4+0.5rGo polycrystalline composite is found to be 40 s and 52 s respectively in comparison to the rGO sample about 58 and 74 s respectively. By adding rGo to the material, the cyclic voltammetry (CV) findings demonstrate improved current density and area of CV loop with increased scan rate. In three-electrode reveals the system, a CoCr2O4-rGo material exhibits a specific capacitance of 226 F/g. Thus, the results reveals that rGo is contributing significantly to the enhancement of a supercapacitor's performance of CoCr2O4. 2023 Elsevier Ltd and Techna Group S.r.l. -
Numerical modeling of novel cage-like cross-linked membranes for enhanced proton conductivity in a high temperature-polymer electrolyte membrane fuel cell
Phosphoric acid (PA)-doped polybenzimidazole (PBI) membranes have encountered several problems associated with high cost, chemical instability, poor solubility in organic solvents, and higher doping level which results in poor mechanical properties and faster degradation of the membrane. Alternative membranes with high proton conductivity and mechanical strength for high-temperature applications are of great interest, one such membrane being cPBI-IL X. The cage-like cross-linked structure of these membranes shows a dual proton transport path due to which proton conductivity is elevated. The ionic liquid content of these membranes improves the PA absorbing capability and shortens the proton transfer path. These membranes exhibit the highest proton conductivity of 13.3 S/m and better durability compared to existing PBI Membranes. A mathematical model is developed and validated versus published experimental results to account for the proton conductivity of these membranes. The developed model is further investigated for a detailed understanding of polarization phenomena and species distribution. 2023 Wiley Periodicals LLC. -
New Insights in the Bubble Wall of NGC 3324: Intertwined Substructures and a Bipolar Morphology Uncovered by JWST
We report the discovery of intertwined/entangled substructures toward the bubble wall of NGC 3324 below a physical scale of 4500 au, which is the sharp edge/ionization front/elongated structure traced at the interface between the H ii region and the molecular cloud. The sharp edge appears wavy in the Spitzer 3.6-8.0 ?m images (resolution ?2?). Star formation signatures have mostly been traced on one side of the ionization front, which lies on the molecular clouds boundary. The James Webb Space Telescopes (JWST) near- and mid-infrared images (resolution ?0.?070.?7) are employed to resolve the sharp edge, which has a curvature facing the exciting O-type stars. The elongated structures are associated with the 3.3 ?m polycyclic aromatic hydrocarbon (PAH) emission, the 4.05 ?m ionized emission, and the 4.693 ?m H2 emission. However, the PAH-emitting structures are depicted between the other two. The H2 emission reveals numerous intertwined substructures that are not prominently traced in the 3.3 ?m PAH emission. The separation between two substructures in the H2 emission is ?1.?1 or 2420 au. The intertwined substructures are traced in the spatial areas associated with the neutral to H2 transition zone, suggesting the origin of these structures by thin-shell instability. Furthermore, an arc-like feature traced in the Spitzer 3.6-8.0 ?m images is investigated as a bipolar H ii region (extent ?0.35 pc) at T d ?25-28 K using the JWST images. A massive-star candidate VPHAS-OB1 #03518 seems to be responsible for the bipolar H ii region. 2023. The Author(s). Published by the American Astronomical Society. -
Identification of Superclusters and Their Properties in the Sloan Digital Sky Survey Using the WHL Cluster Catalog
Superclusters are the largest massive structures in the cosmic web, on tens to hundreds of megaparsec scales. They are the largest assembly of galaxy clusters in the Universe. Apart from a few detailed studies of such structures, their evolutionary mechanism is still an open question. In order to address and answer the relevant questions, a statistically significant, large catalog of superclusters covering a wide range of redshifts and sky areas is essential. Here, we present a large catalog of 662 superclusters identified using a modified friends-of-friends algorithm applied on the WHL (Wen-Han-Liu) cluster catalog within a redshift range of 0.05 ? z ? 0.42. We name the most massive supercluster at z ? 0.25 as the Einasto Supercluster. We find that the median mass of superclusters is ?5.8 1015 M ? and the median size ?65 Mpc. We find that the supercluster environment slightly affects the growth of clusters. We compare the properties of the observed superclusters with the mock superclusters extracted from the Horizon Run 4 cosmological simulation. The properties of the superclusters in the mocks and observations are in broad agreement. We find that the density contrast of a supercluster is correlated with its maximum extent with a power-law index, ? ? ?2. The phase-space distribution of mock superclusters shows that, on average, ?90% of part of a supercluster has a gravitational influence on its constituents. We also show the mock halos average number density and peculiar velocity profiles in and around the superclusters. 2023. The Author(s). Published by the American Astronomical Society. -
The Champions Boat League A Race to Commercialise Festival Cultures
[No abstract available] -
COVID-19 pandemic and trade flows: empirical evidence from selected Asian Pacific countries
Purpose: This paper aims to investigate the effects of the COVID-19 crisis on trade flows in Asia Pacific countries and explores the causality between COVID-19-related shocks and trade. Design/methodology/approach: The authors used two novel techniques, namely, two-stage instrumental-variables (2SIV) approach and Juodis, Karavias and Sarafids (JKS) causality test, to examine trade dynamics in the Asia Pacific region during the pandemic. Findings: Using the monthly trade data of 17 Asia Pacific countries between January 2020 and December 2021, the results were threefold. Firstly, the empirical analysis showed that during the COVID-19 crisis, the flow of exports tended to persist idiosyncratically in comparison to the flow of imports. In particular, a specific finding was that the persistence level in exports was about 20%25% higher than that in imports. Secondly, the authors found that the past values of COVID-19 cases and COVID-19 deaths contain information that helps to predict exports/imports over and above the information contained in the past values of exports/imports alone. Finally, the study established that the government response and stringency indexes have a Granger-causal relationship with exports and imports. Research limitations/implications: For the foreseeable future, these findings have significant policy ramifications. Firstly, if a COVID-19 crisis-like situation emerges in the future, it will be critical for countries to maintain their competitiveness throughout the crisis, like the COVID-19 pandemic, while also rebuilding trade relationships wherever possible. Secondly, because information about government responses and measures can also be used to predict future trade flows, prudent management of government responses and stringent measures will be necessary in a crisis like COVID-19 to achieve the optimum level of exports and imports. At the same time, the trading partners should give up the idea of trade protection and focus on finding a way to balance the conflicting needs of imports and exports. Originality/value: To the best of the authors knowledge, the authors, for the first time, used a 2SIV approach and JKS causality test to examine trade dynamics in the Asia Pacific region during the pandemic. In addition, the authors present the first comprehensive analysis of the evolving relationships between export and import flows and governmental policy responses under COVID-19. As a result, it contributes uniquely to both public and international economics. 2023, Emerald Publishing Limited. -
Jugaad in organizational settings: exploring the Jugaad leadership competencies
The Hindi term 'jugaad' is closely linked to frugal innovation. In resource-scarce environments, organizations can thrive by developing jugaad-related leadership abilities. Previous research on jugaad has focused primarily on individual problem-solving and overlooked the leadership skills necessary to implement it in organizational settings. This study employs a theoretical lens of leadership competency models, interpretive phenomenology, purposive sampling, and an inductive data-driven coding approach to explore the jugaad leadership competencies of 28 Indian business leaders and managers. The study presents the Jugaad Leadership Competency (JLC) model, identifying ten competency clusters exhibited by jugaad leaders. This is the first study to develop a model for jugaad leadership in organizational settings. In environments characterized by scarcity and intense competition, the JLC model can aid individuals and organizations in acquiring the necessary competencies for frugal innovation. The study evaluates the theoretical and practical implications of the findings, their transferability, and limitations and offers suggestions for future research. 2023, Springer Nature Limited. -
Newly designed single-stage dual leg DC-DC/AC buck-boost converter for grid connected solar system
This paper proposes a novel single-stage buck-boost inverter based on dual leg. Modulation techniques, working principle, guidelines for components design, and guidelines are discussed and presented. A theoretical concept is initially tested in Simulink platform and practically verified with a test bench model. A practical model is developed to verify the simulation model and tested different modes of operation are analyzed. The main advantages of the proposed work are as follows: The number of passive components is less, switching frequency components are not high so leakage current is very less, and voltage control in a wide range is achieved without using a DC link capacitor. High efficiency can be achieved due to multi-stage operation. This proposed work is suitable for high/low voltage PV-based energy conversion. Electromagnetic interference is also reduced due to continuous input current. 2023 John Wiley & Sons Ltd. -
Synthesis, Mechanical Properties and Thermal Stability of Polydimethylsiloxane Nanocomposites
The polydimethylsiloxane/nano-graphite (PDMS-NG) nanocomposites were prepared via a two rolled mixing mill and subjected to characterization using techniques such as Transmission Electron Microscopy (TEM), stress-strain analysis during elongation, as well as thermal properties including Thermo-Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The transition temperature was observed to be below-70C for PDMS nanocomposites reinforced with Nano-Graphite (NG). The thermogram from the thermo-gravimetric analysis indicated that at 10%, 20%, 30%, and 50% weight loss, the temperatures for PDMS nanocomposites were higher compared to unfilled PDMS. These findings suggest a substantial improvement in the thermal stability of PDMS-NG nanocomposites. 2023, Books and Journals Private Ltd. All rights reserved.