Browse Items (5511 total)
Sort by:
-
On-off fluorescence detection of exposed phosgene via pyrazine ring formation on a triphenyl amine backbone supplemented with a theoretical approach and practical environmental applications
Using 4-(diphenylamino)benzaldehyde as the fluorophore and 2,3-diaminomaleonitrile, a fluorescent probe known as 2-amino-3-(((E)-4-(diphenylamino)benzylidene)amino)-maleonitrile (ADM) has been developed for the selective detection of phosgene through a unique cyclization pathway producing a substituted pyrazine derivative attached to a triphenyl amine backbone. This reaction led to a notable reduction in the emission intensity of ADM at 565 nm. This is the first study that reports ADM as a sensory material for the selective detection of phosgene, achieved by forming a new heterocyclic pyrazine structure. With a quick response time of only 80 seconds, the detection limit of the probe ADM towards phosgene has been calculated as 4.23 ?M. Several spectroscopic methods, including UV-vis, emission spectroscopy, mass spectrometry, and computational investigations are used to study the sensing behavior. In practical applications, the sensor ADM can be used for soil analysis, the dipstick method, and the detection of phosgene from chlorinated hydrocarbon sources such as dichloromethane, chloroform and household solvents like paint remover. 2024 The Royal Society of Chemistry. -
One Pot Hydrothermal Synthesis and Application of Bright-yellow-emissive Carbon Quantum Dots in Hg2+ Detection
Carbon quantum dots (CQD) have drawn great interest worldwide for their extensive application as sensors due to their extraordinary physical and chemical characteristics, good biocompatibility, and high fluorescence in nature. Here, we demonstrate a technique for detecting mercury (Hg2+) ion using a fluorescent CQD probe. Ecology is concerned about the accumulation of heavy metal ions in water samples due to their harmful effects on human health. Sensitive identification and removal of metal ions from water samples are required to reduce heavy metals risk. To find out Mercury in the water sample, carbon quantum dots were used and synthesized by 5-dimethyl amino methyl furfuryl alcohol and o-phenylene diamine through the hydrothermal technique. The synthesized CQD shows yellow emission when exposed to UV irradiation. Mercury ion was used to quench carbon quantum dots, and it was found that the detection limit was 5.2 nM with a linear range of 15100 M. The synthesized carbon quantum dots were demonstrated to efficiently detect Mercury ions in real water samples. 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. -
One-pot hydrothermal synthesis of 3D garland BiOI, spherical ZnO, and CNFs onto Ni foam: Supercapacitor performance with enhanced electrochemical properties
This study reported one-pot hydrothermal synthesis of 3D garland BiOI, spherical ZnO, and carbon nanofibers (CNFs) onto Ni foam substrate with improved supercapacitor performance and enhanced electrochemical properties. The synthesized nanocomposites exhibited high specific capacitance (SC) of 1073 g?1 at a current density of 1 A/g and excellent cycling stability with 88.6% retention of original capacity after 5000 cycles in 2M KOH aqueous solution. The findings highlight the potential of 3D materials for use as electrode materials in advanced supercapacitor applications due to their high energy storage capabilities. 2024 Elsevier Ltd -
One-pot hydrothermal synthesis of MWCNTs/NiS/graphitic carbon nitride as next generation asymmetric supercapacitors
Fabricating new electrode materials with high capacitive properties is crucial in contemporary research. The construction of hybrid supercapacitors developed using transition metal-sulfides and carbonaceous materials provides significant surface area and distinctive charge storage characteristics. In the present work, NH2-multiwalled carbon nanotubes/NiS/g-C3N4 (MNG) hybrid was synthesized by a one-pot hydrothermal method, and pristine g-C3N4 using thermal method. The morphological studies of the hybrid materials show the presence of tube like MWCNTs, sphere-like NiS, and sheet like g-C3N4. The uniform distribution of all the components in the hybrid helps in exhibiting excellent electrochemical performances. The prepared electrode material shows a specific capacitance of 2432 F g?1 at a current density of 4 A g?1. Furthermore, following a series of 10,000 cycling tests, the hybrid ternary composite retains 98 % of its initial capacitance. An asymmetric coin cell of MNG//AC was fabricated with an exceptional energy density of 73.3 Wh kg?1 and a power density of 1599.2 W kg?1. This remarkable rate performance and cycle stability exhibited by the material indicate its potential as a highly efficient electrode material for supercapacitors. 2024 Elsevier B.V. -
One-pot sustainable synthesis of novel pyrido[2,3-d]pyrimidinones and their evaluation for antitubercular and anticancer activity
A novel green protocol for the construction of diversified pyrido[2,3-d]pyrimidinones was accomplished by a single-pot reaction of aryl aldehydes, Meldrum's acid, thiobarbituric acid, and ammonium acetate/aniline in H2O using ?-proline as an expeditious reusable catalyst at room temperature (26 C). Our strategy provides an innovative synthetic avenue for the construction of pyrido[2,3-d]pyrimidinones, as well as several advantages over traditional methods, including a simple procedure, shorter reaction duration, excellent yields, safe handling, easy workup, catalyst recovery, and environmental compatibility. Furthermore, the synthesised compounds were tested for their impact on different cell lines and microorganisms. Compounds 5d and 5e were particularly effective against Mycobacterium tuberculosis (antitubercular), human breast cancer cells (MCF-7), lung cancer cells (A549 and NCI-H460), and both Gram-positive (S. pyogenes) and Gram-negative (E. coli) bacteria. The derivatives with hydroxyl and nitro substitutions [5e, 5f] showed the highest potency against MCF-7, A549, and NCI-H460 cell lines, with IC50 values of 3.684.36, 3.823.41, and 11.3412.28 g/mL, respectively. 2024 The Author(s) -
One-Pot Synthesis of Silver Nanoparticles Derived from Aqueous Leaf Extract of Ageratum conyzoides and Their Biological Efficacy
The main objective of the present research work is to assess the biological properties of the aqueous plant extract (ACAE) synthesised silver nanoparticles from the herbal plant Ageratum conyzoides, and their biological applications. The silver nanoparticle syntheses from Ageratum conyzoides (Ac-AgNPs) were optimised with different parameters, such as pH (2, 4, 6, 8 and 10) and varied silver nitrate concentration (1 mM and 5 mM). Based on the UVvis spectroscopy analysis of the synthesised silver nanoparticles, the concentration of 5 mM with the pH at 8 was recorded as the peak reduction at 400 nm; and these conditions were optimized were used for further studies. The results of the FE-SEM analysis recorded the size ranges (~3090 nm), and irregular spherical and triangular shapes of the AC-AgNPs were captured. The characterization reports of the HR-TEM investigation of AC-AgNPs were also in line with the FE-SEM studies. The antibacterial efficacies of AC-AgNPs have revealed the maximum zone of inhibition against S. typhi to be within 20 mm. The in vitro antiplasmodial activity of AC-AgNPs is shown to have an effective antiplasmodial property (IC50:17.65 ?g/mL), whereas AgNO3 has shown a minimum level of IC50: value 68.03 ?g/mL, and the Ac-AE showed >100 ?g/mL at 24 h of parasitaemia suppression. The ?-amylase inhibitory properties of AC-AgNPs have revealed a maximum inhibition similar to the control Acarbose (IC50: 10.87 ?g/mL). The antioxidant activity of the AC-AgNPs have revealed a better property (87.86% 0.56, 85.95% 1.02 and 90.11 0.29%) when compared with the Ac-AE and standard in all the three different tests, such as DPPH, FRAP and H2O2 scavenging assay, respectively. The current research work might be a baseline for the future drug expansion process in the area of nano-drug design, and its applications also has a lot of economic viability and is a safer method in synthesising or producing silver nanoparticles. 2023 by the authors. -
One-Pot Synthesis of Silver Nanoparticles from Garcinia gummi-gutta: Characterisation, Antimicrobial, Antioxidant, Anti-Cancerous and Photocatalytic Applications
Background: Methods like the bio-synthesis of silver nanoparticles (Ag NPs) using plant extracts have become promising due to their eco-friendly approach. The study aimed to examine the utilization of Garcinia gummi-gutta fruit phytochemicals as agents in the biosynthesis of Ag NPs, evaluation of the antimicrobial, antioxidant, and anti-cancerous properties, as well as the photocatalytic ability of bio-synthesized Ag NPs against Crystal Violet (CV), a triphenylmethane dye. Methods: The characterization of the physical properties of the Ag NPs synthesized via the green route was done using UVVis spectrophotometry (UVVis), X-ray Diffraction (XRD), Fourier Transform Infrared Spectrophotometry (FTIR), Scanning Electron Microscopy (SEM), Zeta potential analysis, and Transmission Electron Microscopy (TEM). The dye degradation efficiency of CV was determined using synthesized Ag NPs under UV light by analyzing the absorption maximum at 579 nm. The antimicrobial efficacy of Ag NPs against E. coli, S. aureus, Candida tropicalis, and Candida albicans was examined using the broth dilution method. The antioxidant and anti-cancer properties of the synthesized Ag NPs were assessed using the DPPH and MTT assays. Results: The UV analysis revealed that the peak of synthesized Ag NPs was 442 nm. Data from FTIR, XRD, Zeta potential, SEM, and TEM analysis confirmed the formation of nanoparticles. The SEM and TEM analysis identified the presence of spherical nanoparticles with an average size of 29.12 nm and 24.18 nm, respectively. Maximum dye degradation efficiency of CV was observed at 90.08% after 320 min without any silver leaching, confirming the photocatalytic activity of Ag NPs. The bio-efficiency of the treatment was assessed using the Allium cepa root growth inhibition test, toxicity analysis on Vigna radiata, and Brine shrimp lethality assay. Conclusions: The findings revealed the environmentally friendly nature of green Ag NPs over physical/chemically synthesized Ag NPs. The synthesized Ag NPs can effectively be used in biomedical and photocatalytic applications. Copyright: 2023 The Author(s). -
One-step synthesized Pt-dispersed N, P co-doped graphene as an efficient oxygen reduction reaction ORR electrocatalyst
A simple yet effective strategy to simultaneously deposit Platinum and co-doped (Nitrogen & Phosphorous) graphite oxide (rGO) using microwave irradiation has been carried out, labeled as Pt/NP-rGO. The successful deposition of Pt was confirmed using X-ray diffractogram (XRD), transmission electron microscope (TEM), and selected area electron diffraction (SAED) pattern. The Pt particles with average size of 3.5nm were deposited during microwave irradiation. Further, co-doping was confirmed using X-ray photoelectron spectroscopy (XPS). The synthesized Pt/NP-rGO was analyzed in situ as an oxygen reduction reaction electrocatalyst in acidic medium. Our results indicate that Pt/NP-rGO follows a four e? ORR process attributed to increased adhesion between the Pt and N, P co-doped graphene oxide due to e? transfer from graphene to N and P atoms, thus indicating its potential in energy-related applications as an effective ORR electrocatalyst. The Author(s), under exclusive licence to The Materials Research Society 2024. -
Online cooperative learning: exploring perspectives of pre-service teachers after the pandemic
Mainly, research has explored pre-service teachers perspectives toward cooperative learning within face-to-face teaching. However, in a post-pandemic scenario, previous research has yet to effectively explore pre-service teachers (PSTs) perspectives toward online cooperative learning (OCL) in teacher education programs. So, recognizing the gap in the literature, this paper aims to explore the perspectives of PSTs towards OCL. The researchers employed a qualitative research design for the present study. The researchers conducted semi-structured interviews with 10 PSTs who underwent OCL during the pandemic. These PSTs may possess digital proficiency, virtual collaboration abilities, flexibility in evolving educational environments, and an enhanced understanding of online cooperative learning methodologies within modern education. Researchers employed a thematic analysis to analyze the qualitative data obtained. The various themes that emerged from the study are perceived benefits of OCL, challenges to OCL, technological proficiency, learning strategies and support, and building a supportive online learning community. Future researchers may contribute to advancing effective online learning practices by gaining a deeper understanding of pre-service teachers perspectives towards OCL through research on a larger scale, including various teacher education programs in various countries. 2024, Institute of Advanced Engineering and Science. All rights reserved. -
Online fake review identification based on decision rules
Posting of online reviews play a dominant role in sharing the customers opinion in social Medias. But the challenge is how to trust these reviews. Many researchers carried their work on sentimental analysis, predictions or forecasting but very few focused on fake reviews analysis. Fake reviews also change the mood of the people on their buying pattern. In the online shopping at a greater extent. In this paper, several conditions are applied on the reviews to identify fake reviews using support vector machines. Experimental results are validated using various accuracy measures and compared to state of the art methods to demonstrate the efficacy of the proposed method. 2019, World Academy of Research in Science and Engineering. All rights reserved. -
Open global shadow graph and its zero forcing number
Zero forcing number of a graph is the minimum cardinality of the zero forcing set. A zero forcing set is a set of black vertices of minimum cardinality that can colour the entire graph black using the colour change rule: each vertex of G is coloured either white or black, and vertex v is a black vertex and can force a white neighbour only if it has one white neighbour. In this paper we identify a class of graph where the zero forcing number is equal to the minimum rank of the graph and call it as a new class of graph that is open global shadow graph. Some of the basic properties of open global shadow graph are studied. The zero forcing number of open global shadow graph of a graph with upper and lower bound is obtained. Hence giving the upper and lower bound for the minimum rank of the graph. 2023, Proyecciones. All Rights Reserved. -
OpenStackDP: a scalable network security framework for SDN-based OpenStack cloud infrastructure
Network Intrusion Detection Systems (NIDS) and firewalls are the de facto solutions in the modern cloud to detect cyberattacks and minimize potential hazards for tenant networks. Most of the existing firewalls, perimeter security, and middlebox solutions are built on static rules/signatures or simple rule matching, making them inflexible, susceptible to bugs, and difficult to introduce new services. This paper aims to improve network management in OpenStack Clouds by taking advantage of the combination of software-defined networking (SDN), Network Function Virtualization (NFV), and machine learning/artificial intelligence (ML/AI) and for making networks more predictable, reliable, and secure. Artificial intelligence is being used to monitor the behavior of the virtual machines and applications running in the OpenStack SDN cloud so that when any issues or degradations are noticed, the decision can be quickly made on how to handle that issue, being able to analyze data in motion, starting at the edge. The OpenStackDP framework comprises lightweight monitoring, anomaly-detecting intelligent sensors embedded in the data plane, a threat analytics engine based on ML/AI algorithms running inside switch hardware/network co-processor, and defensive actions deployed as virtual network functions (VNFs). This network data plane-based architecture makes high-speed threat detection and rapid response possible and enables a much higher degree of security. We have built the framework with advanced streaming analytics technologies, algorithms, and machine learning to draw knowledge from this data that is in motion before the malicious traffic goes to the tenant compute nodes or long-term data store. Cloud providers and users will benefit from improved Quality-of-Services (QoS) and faster recovery from cyber-attacks and compromised switches. The multi-phase collaborative anomaly detection scheme demonstrates an accuracy of 99.81%, average latencies of 0.27 ms, and response speed within 9 s. The simulations and analysis show that the OpenStackDP network analytics framework substantially secures and outperforms prior SDN-based OpenStack solutions for Cloud architectures. 2023, The Author(s). -
Operational pattern forecast improvement with outlier detection in metro rail transport system
Transportation is an unavoidable part of every humans life. The mobility system handles the transport of humans from different places using various transport modes. According to a station in a populated area, the main problem is the presence of traffic in peak hours and wasting their valuable time on the road. The only medium which runs above the traffic is metro rails/subways. For these reasons, metro rails become a point of interest for each researchers prophecy and provide valuable recommendations for the smooth functioning of services. Even though, in many cases, the metro systems are affected by abnormal passenger flow. So, this study handles abnormal passenger flow detection and station clustering for the behavior study of a passenger flow system. The research compares outlier detection and anomaly identification for the behavioral analysis of the metro rail passenger flow. The study use data from Kochi Metro Rail Limited for the period 2017 to 2019. Outlier removal has used in passenger flow data before building a forecasting system. In pattern recognition algorithm those components which lie outside the patterns can be considered abnormal (anomaly).The outliers are the component falling apart from the region of interest. The effect of removing the outlier from the time-series pattern is studied against the outlier included pattern to show the improvement. 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. -
Operational plan on teaching-learning at departmental level /
Journal Of Education & Social Policy, Vol.1, Issue 2, pp.77-79, ISSN No: 2375-0790 (Online) 2375-0782 (Print). -
Opinion mining on newspaper headlines using SVM and NLP
Opinion Mining also known as Sentiment Analysis, is a technique or procedure which uses Natural Language processing (NLP) to classify the outcome from text. There are various NLP tools available which are used for processing text data. Multiple research have been done in opinion mining for online blogs, Twitter, Facebook etc. This paper proposes a new opinion mining technique using Support Vector Machine (SVM) and NLP tools on newspaper headlines. Relative words are generated using Stanford CoreNLP, which is passed to SVM using count vectorizer. On comparing three models using confusion matrix, results indicate that Tf-idf and Linear SVM provides better accuracy for smaller dataset. While for larger dataset, SGD and linear SVM model outperform other models. Copyright 2019 Institute of Advanced Engineering and Science. All rights reserved. -
Optical and electrical properties of SnS semiconductor crystals grown by physical vapor deposition technique
Tin sulfide (SnS) is a material of interest for use as an absorber in low cost solar cells. Single crystals of SnS were grown by the physical vapor deposition technique. The grown crystals were characterized to evaluate the composition, structure, morphology, electrical and optical properties using appropriate techniques. The composition analysis indicated that the crystals were nearly stoichiometric with Sn-to-S atomic percent ratio of 1.02. Study of their morphology revealed the layered type growth mechanism with low surface roughness. The grown crystals had orthorhombic structure with (0 4 0) orientation. They exhibited an indirect optical band gap of 1.06 eV and direct band gap of 1.21 eV with high absorption coefficient (up to 103 cm-1) above the fundamental absorption edge. The grown crystals were of p-type with an electrical resistivity of 120 ? cm and carrier concentration 1.52015 cm-3. Analysis of optical absorption and diffuse reflectance spectra showed the presence of a wide absorption band in the wavelength range 3001200 nm, which closely matches with a significant part of solar radiation spectrum. The obtained results were discussed to assess the suitability of the SnS crystal for the fabrication of optoelectronic devices. 2011 Elsevier B.V. All rights reserved. -
Optical and Electrochromic Properties of CeO2/WO3 Hybrid Thin Films Prepared by Hydrothermal and Sputtering
Innovative chromogenic nanostructures like hybrids but also composite materials can be increased electrochromic efficiency because of their prospective application values in low-power displays, smart windows, electronic papers, and car anti-reflect mirrors. We used a hydrothermal approach to make Cerium oxide Nanorods have various ratios in this report. DC magnetron sputtering procedures cover the generated cerium oxide nanorods of various diameters with a tungsten oxide layer in one step. the surface plasmon effect varies depending on the size of Ce Nanorods, and this phenomenon impacts electrochromic results. the electrochromic performances of CeO2/WO3 nanorods on FTO-coated glass slides are examined using a 0.5 M solution of H2SO4 as the electrolyte in the visible range. These structures produce considerable optical modulation (47 %, 45 %, and 41 % at 700 nm) and coloration efficiency (11.6, 7.57, and 10.84 cm2C-1 at 700 nm). 2022 Seventh Sense Research Group -
Optical characterization of oxadiazoles analogues doped PMMA film for photonic application
In the present study, newly synthesized nitrobenzene derivatives (PBT and PBF) doped poly(methyl methacrylate) films were prepared using spin coating techniques, and their optical properties were analyzed. The absorption spectra of various weight percentages (0.02%, 0.1%, 0.2%, and 0.3%) of nitrobenzene derivative-doped polymer films were recorded using a UVvisible spectrometer. From the absorption spectra, optical properties such as refractive index, band gap energy, extinction coefficient, and dielectric constant were calculated. The effect of doping on the optical properties of PMMA was investigated, with results revealing normal dispersive behavior from the refractive index and extinction coefficient. Atomic force microscopy and scanning electron microscopy images indicated that the synthesized films have a low degree of roughness and a smooth surface. Additionally, the nonlinear optical properties of the PBF-doped polymer film were investigated, and the ? value was determined to be 7.403cm/W. Overall, the findings suggest that PBF-doped polymer films are promising candidates for photonic applications. Indian Association for the Cultivation of Science 2024. -
Optical design studies for national large optical-IR telescope
A 1012 m class national large optical-IR telescope (NLOT) is envisaged to meet the growing scientific requirements in astronomy and astrophysics. Telescopes of such dimensions can only be made by segmenting the primary mirror, as it eases a more prominent primary mirrors fabrication, transportation, operation, and maintenance process. This paper presents the various optical designs analyzed for NLOT that can be fabricated using the India TMT Optics Fabrication Facility (ITOFF) at the Centre for Research and Education in Science and Technology (CREST) campus. We present the primary mirror segmentation details, its ideal optical performance, and study each designs advantages and technical complexities. Based on the above analysis, we have narrowed it down to an optimal design, and its performance analysis is also discussed. Indian Academy of Sciences 2024. -
Optical properties of MnTe2 few-layer quantum dots
Quantum dots (QDs) are gaining attention as a possible emissive material that might be used in flexible optoelectronic and photonic systems. In the present work, the temperature-dependent photoluminescence (TDPL) property of manganese di-telluride (MnTe2) QDs was investigated. The room-temperature PL is attributed to the abrupt breakage of the large-area MnTe2 nanosheets by ultrasonication, which integrates defect-mediated localized trap states inside the electronic bandgap. As a result, deliberately generated defect states ultimately generate such PL emission of QDs. Density functional theory (DFT) results further validate the experimental interpretations of the origin of TDPL. In addition, through an in-situ liquid diffusion approach, the QDs were also integrated into a NaCl matrix. Due to light scattering properties, the hybrid crystals exhibit fluorescence centres at various excitation wavelengths. These results suggest that these MnTe2 QDs can be used as an effective basis for future flexible optoelectronic applications. 2024 Elsevier B.V.