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MoS2, a new perspective beyond graphene
Owing to the fascinating structural, optical, electrical, chemical properties, graphene has created new paradigm in the field of nanoscience and the common crystalline structures that can be exfoliated include the layered van der Waals (vdW) solids such as boron nitride, transition metal dichalcogenides (TMDCs), black phosphorus, and the layered ionic solids. Here, we bring forth the state-of-art-of materials dominated by their two-dimensional (2D) geometry beyond graphene. Being one of the most well-studied families of vdW layered materials, molybdenum disulphide (MoS2) belonging to TMDC family has gained considerable research interest. The present work is focused on attempts to optimize and characterize this material with unique properties for a host of applications. The work resolves the hydrothermal growth of hexagonal MoS2 nanoflakes with attracting optical and magnetic properties providing strong evidence for the spin orbit split valence bands of these nanostructures. The enhanced electrocatalytic activity, excitation wavelength dependent down-conversion and up-conversion photoluminescence, growth of structural polymorphs using simple hydrothermal method, and the efficient anticancer properties of MoS2 nanostructures providing greater insight into energy and biomedical applications are also discussed. The improved catalytic activity of MoS2-based nanostructures reveals the increasing number of accessible active sites, formation of large surface area and is greatly beneficial for accomplishing a clean, environmental-friendly, inexpensive hydrogen mission for energy storage and conversion applications. The synergistic effect of the MoS2 nanocomposites was able to impede angiogenesis, tumor growth, and epithelial to mesenchymal transition, elucidating the anticancer efficacy. Understanding and exploiting such unique properties of these 2D materials paves new horizons toward novel technological advances in electronic and medical field. 2021 Elsevier Inc. All rights reserved. -
MoS2-TiO2 Nanocomposites for Enhanced Photo-electrocatalytic Hydrogen Evolution
The investigation on the designing and fabrication of highly efficient electrocatalysts for hydrogen evolution reaction (HER) is critical for future applications in renewable sustainable energy. The present work reports the hydrothermal synthesis of two-dimensional MoS2 and MoS2-TiO2 nanostructures. The as-prepared nanostructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman analysis, UV-vis-NIR, and photoluminescence spectrophotometry and vibrating sample magnetometer (VSM). Systematic electrochemical measurements for HER were performed and MoS2-TiO2 nanocomposites demonstrated the lowest onset potential in comparison with MoS2. The results suggest that the nanofusion interface between MoS2 nanoflakes and TiO2 nanoparticles induced an efficient charge transfer from the conduction band of MoS2 to TiO2 and favored the reduction of H+ at active sites. We believe the present work can open up new possibilities that would provide deep insights for the rational design of 2D materials-based catalysts for energy storage and conversion applications. 2023 The Electrochemical Society (ECS). Published on behalf of ECS by IOP Publishing Limited. -
Morphology-dependent supercapacitive properties of Co3O4 nanomaterials synthesized via coprecipitation and hydrothermal methods
The supercapacitive properties of Co3O4 nanocrystalline powders with two different morphologies synthesized by coprecipitation (referred to as Co3O4C) and hydrothermal (referred to as Co3O4-H) methods were compared and studied. The samples were analyzed for their phase purity, crystal structure, surface morphology, and surface area. Both samples were found to be single-phase nanostructures with a normal spinel-type cubic crystal structure (space group Fd3m), as indicated by Raman and XRD (X-ray diffraction) data analyses. TEM (Transmission electron microscopy) images clearly show that the Co3O4C sample exhibits spherical particles with a mean size of 10 nm. On the other hand, the Co3O4H sample shows a flower-like assembly of particles. The Co3O4C sample has a higher specific surface area than the Co3O4-H sample due to its smaller particle size. XPS (X-ray photoelectron spectroscopy) data were collected to analyze the chemical states and cation distribution of the samples, revealing a 2:1 ratio of Co3+ and Co2+ in both samples. Both samples displayed pseudocapacitive behaviour in CV (cyclic voltammetry) and GCD (galvanostatic chargedischarge) analyses. Despite having a smaller surface area, the Co3O4H electrode exhibited a higher CS (specific capacitance) compared to the Co3O4C electrode at all current densities when tested using 1 M KOH electrolyte. At a specific current density (0.5 A/g), the Cs values for Co3O4C and Co3O4H are found to be 366 F/g and 233 F/g, respectively. As the current density increases, the specific capacitance of both electrodes decreases, but this reduction is more prominent for Co3O4-C than Co3O4-H. The study indicates that besides surface area, the morphology of the sample also plays a crucial role in determining the capacitance of a material. 2023 Elsevier B.V. -
Morphology of interstellar medium using multi-wavelength observations
The interstellar medium (ISM) is the matter that exists between the stars in a galactic system. The structure and composition of a galaxy can be understood by a study of the ISM. Our Galaxy is the only place where the observations of the ISM can be resolved and studied in great detail. There are various archived observations from space-based and ground-based telescopes spanning a large region of the electromagnetic spectrum. Combining these different observations with one another will help to study the ISM on a large scale. -
Morphology of interstellar medium using multi-wavelength obervations
The interstellar medium (ISM) is the matter that exists between the stars in a galactic system. The structure and composition of a galaxy can be understood by a study of the ISM. Our Galaxy is the only place where the observations of the ISM can be resolved and studied in great detail. There are various archived observations from space-based and ground based telescopes spanning a large region of the electromagnetic spectrum. Combining these different observations with one another will help to study the ISM on a large scale. We have compiled some such observations and analyzed the column density data, to study the ISM and make the database available to the scientific community for further investigations. The data was taken from papers published over a span of 60 years (1951 to 2010). The column densities in these papers were derived using different methods and observations from various telescopes operating in different wavelengths. We compiled these diverse data into a single catalogue and analysed the data. We studied the correlations between the line of sight gas and dust and reported new correlations not published before (APJS, 119(1), 8, 2012). We also studied the spatial distribution of the interstellar gas and dust and have estimated the corresponding exponential vertical scale heights. There also exists a wide range of photometric data from various telescopes which can be combined to cover a large range of wavelengths. We have made use of Galaxy Evolution Explorer (GALEX) photometric data in conjunction with Sloan Digital Sky Survey (SDSS) data to obtain the point sources observed by both missions. GALEX observed in two bands simultaneously, the far-ultraviolet (FUV: 1350 1750 and the near-ultraviolet (NUV: 1750 - 2750 , while SDSS observed in five bands u, g, r, i and z, with effective wavelengths ranging from 3551 to 8931 GALEX and SDSS together provide photometric data ranging from the far-ultraviolet to the near-infrared. -
Morphological Characterization of Selected Aliphatic and Aromatic Hydrocarbons.
In the last few years considerable interest has been aroused in the study of amorphous carbon. Amorphous carbon has a wide range of properties that are primarily controlled by the different bond hybridizations possible in such materials. This gives different properties like high strength, flexibility etc. Due to these properties, they are used in thin film technology and in nanoscale electronic devices. Films can range from those with high transparency and are hard and diamond-like, through to those which are opaque, soft and graphitic-like. Application areas include field emission cathodes, electronic devices, medical and optical coatings. Hence study of different carbon structures has been of great interest for many researchers. Several techniques have been used to study various sources of carbon. Hydrocarbons are the most abundant sources of carbon. The majority of hydrocarbons found, naturally occur in crude oil and the decomposition of these give hydrogen and carbon. Incomplete combustion of hydrocarbons leads to the production of polycyclic aromatic hydrocarbons. Hydrocarbon combustion therefore mainly have aromatic and aliphatic chains of carbon. Hydrocarbons are by far the most widespread precursors among carbon sources employed in the production of carbon nanotubes and carbon nanosphers. In the present study diesel soot, camphor soot and coal has been used as precursors for nanomaterials. Impurities in the samples can reduce efficiency of production. Mineral matter encompasses dissolved salts in the pore water and inorganic elements associated with the organic compounds, as well as crystalline and non-crystalline mineral particles. Quantitative analysis of minerals and other inorganics contributes to defining coal quality. Therefore a study on effects of bio and base leaching on coal samples are also done. XRD is one of the majorly used techniques to deduct the various structural parameters like interlayer spacing of crystalline (d002) structure, crystallites size (La, Lc), aromaticity (fa), number of layers of carbon atoms per aromatic lamellae(n). According to Scherrer, crystallite size varies inversely with peak width. Therefore it is a known fact that a broad hump in the spectrum indicates the presence of nano layers. These parameters are determined from the intensity profiles of the sample hydrocarbons. Also the structure of the hydrocarbon can be characterized using NMR and SEM EDS. 1H NMR spectra can yield structural information that allows classification of complex mixtures containing hundreds of aromatic, naphthenic, paraffinic, olefinic, and isoparaffinic compounds. SEM/EDS techniques allow both inorganic analysis of bulk materials and determination of chemistry and abundance of microscopic constituents. SEM analysis also gives us the size of nano particles formed in the sample. EDS allows one to identify what those particular elements are and their relative proportions. CHNS analysis gives the elemental composition of the samples. The study shows that the carbonaceous soot produced from combustion of diesel in engine show the presence of significant amount of carbon nanomaterials. The SEM micrographs indicate that nanoparticle present in diesel soot is clusters of carbon nanospheres. EDS analysis reveals the soot particles to be composed of primarily carbon and oxygen along with hydrogen. NMR spectrum of the soot reveals significant aliphatic component with predominance of methyl and methylene groups on ?and ?? positions to aromatic rings. Camphor soot XRD analysis shows presence of ordered layers of nanolayers and laso the presence of CNTs. The SEM micrographs of camphor show the presence of carbon nanostructures. The EDS analysis shows more of carbon and oxygen along with aluminium, silicon and potassium. Study of coal samples treated with biological leaching agents reveals that Penicillium spp (PE) treated sample is having more of a graphitic or ordered structure and the d002 spacing of this sample is 3.37 ?? which is close to graphite. XRD data of coal sample treated with base leaching agents confirms the turbostratic structure of coal. The SEM micrographs of the samples show that KN has more graphite like sheet structures. -
Morphological and Elemental Investigations on CoFeBO Thin Films Deposited by Pulsed Laser Deposition for Alkaline Water Oxidation: Charge Exchange Efficiency as the Prevailing Factor in Comparison with the Adsorption Process
Abstract: Mixed transition-metals oxide electrocatalysts have shown huge potential for electrochemical water oxidation due to their earth abundance, low cost and excellent electrocatalytic activity. Here we present CoFeBO coatings as oxygen evolution catalyst synthesized by Pulsed Laser Deposition (PLD) which provided flexibility to investigate the effect of morphology and structural transformation on the catalytic activity. As an unusual behaviour, nanomorphology of 3D-urchin-like particles assembled with crystallized CoFe2O4 nanowires, acquiring high surface area, displayed inferior performance as compared to coreshell particles with partially crystalline shell containing boron. The best electrochemical activity towards water oxidation in alkaline medium with an overpotential of 315 mV at 10 mA/cm2 along with a Tafel slope of 31.5 mV/dec was recorded with coreshell particle morphology. Systematic comparison with control samples highlighted the role of all the elements, with Co being the active element, boron prevents the complete oxidation of Co to form Co3+ active species (CoOOH), while Fe assists in reducing Co3+ to Co2+ so that these species are regenerated in the successive cycles. Thorough observation of results also indicates that the activity of the active sites play a dominating role in determining the performance of the electrocatalyst over the number of adsorption sites. The synthesized CoFeBO coatings displayed good stability and recyclability thereby showcasing potential for industrial applications. Graphic Abstract: [Figure not available: see fulltext.] 2021, The Author(s). -
More Than Legacy: Stalins Political Formula That Keeps DMK on Top
Stalins mix of legacy, governance, and resistance seems to have struck the right chord with the TN electorate. -
More insights into bar quenching: Multi-wavelength analysis of four barred galaxies
The underlying nature of the process of star formation quenching in the central regions of barred disc galaxies that is due to the action of stellar bar is not fully understood. We present a multi-wavelength study of four barred galaxies using the archival data from optical, ultraviolet, infrared, CO, and HI imaging data on star formation progression and stellar and gas distribution to better understand the process of bar quenching. We found that for three galaxies, the region between the nuclear or central sub-kiloparsec region and the end of the bar (bar region) is devoid of neutral and molecular hydrogen. While the detected neutral hydrogen is very negligible, we note that molecular hydrogen is present abundantly in the nuclear or central sub-kiloparsec regions of all four galaxies. The bar co-rotation radius is also devoid of recent star formation for three out of four galaxies. One galaxy shows significant molecular hydrogen along the bar, which might mean that the gas is still being funnelled to the centre by the action of the stellar bar. Significant star formation is also present along the bar co-rotation radius of this galaxy. The study presented here supports a scenario in which gas redistribution as a result of the action of stellar bar clears the bar region of fuel for further star formation and eventually leads to star formation quenching in the bar region. 2020 ESO. -
Moral Identity, Moral Emotions and Maladaptive Personality Traits Among Adolescents in South Korea by Doo Jong Kim
The rule of survival of the fittest often thwarted the leap towards holistic development. How does morality associate with personality in adolescent development? Drawing on the theories of Augusto Blasi and Gordon Allport, the present study took a morality-personality integrative approach to adolescent development and viewed moral identity centrality as an agentic drive for their holistic growth. It aimed to determine whether moral identity centrality, other-praising moral emotion, and personality dysfunction of maladaptive personality traits are coherent in predicting antisocial behaviour in a sample of 436 Korean adolescents (M = 15.71 years, SD = .70; female 48.4%). The present study set up three hypotheses in the structural relationship of research variables (i.e., moral identity centrality, other-praising moral emotion, personality dysfunction of maladaptive personality traits and antisocial behaviour). Hypothesis 1: Personality dysfunction of multiple maladaptive personality traits predicts antisocial behaviour. Hypothesis 2: Other-praising moral emotion and personality dysfunction mediate moral identity centrality and antisocial behaviour. Hypothesis 3: Sex does not make notable differences in the structural relationship of research variables. The study analyzed the data mainly through structural equation modelling (SEM). As a result, all hypotheses were accepted. First, four multiple maladaptive traits, i.e., negative affectivity, antagonism, disinhibition, and psychoticism, significantly predicted adolescents antisocial behaviour (and#946; = .791, p lt .001) (Hypothesis 1). Second, the modified structural model showed a serial multiple mediation effect of other-praising moral emotion and personality dysfunction between moral identity centrality and antisocial behaviour (Hypothesis 2). Third, multi-group analyses showed apparent coherence among research variables regardless of sex (Hypothesis 3). -
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MOOCs: A disruptive teaching-learning process in interdisciplinary boundaries /
International Journal of Language & linguistics, Vol.1, Issue 2, pp.54-61, ISSN No: 2374-8869. -
Monopsonistic exploitation in contract farming: Articulating a strategy for grower cooperation
Contract farming has been considered a new hope to instil dynamism in third world agriculture. However, there remains serious concern whether small peasants will be able to benefit from this system since buyers may often be a single large or at most, few large corporations, a typical case of monopsony. In this paper we question the basis of the fears that are often raised in the literature. A clear analytical approach to understanding the (economic) meaning of monopsony helps us articulate a strategy for grower cooperation that could effectively deal with monopsony power in contract farming systems. Copyright 2007 John Wiley & Sons, Ltd. -
Monoclinic yttrium oxide quantum dots surface modified by biotin for bioimaging applications
Semiconductor nanoparticles or quantum dots are one of the central topics of interest in material science research due to its size dependent physical and chemical characteristics and applications in different areas from display to biomedical fields. This work reports the first-time synthesis of biotin functionalized monoclinic yttrium oxide quantum dots at low temperature and its application in live cell imaging. The presence of biotin was confirmed through FTIR measurements. HRTEM analysis confirmed the formation of small spherical quantum dots with an average size of 3.8 nm. Zeta potential measurements gave a negative surface charge of -26.9 mV confirming colloidal stability. The quantum dots show sharp absorption in the short UV region and PL experiments delivered defect related intense blue fluorescence emission. The material is nontoxic to both normal (L929) and cancer (MCF 7) cells and the live cell imaging experiments performed on MCF 7 cells show specific binding to the cells and presented bright fluorescence emission from the cells thus confirming the applicability of the material in both display industry and cancer cell imaging. 2023 Elsevier B.V. -
Monoclinic Y2O3: Ce nanophosphors synthesized by wet chemical precipitation method
UV emitting nanophosphors draws attention from many researchers currently due to the diverse applications ranging from UV LEDs to phototherapy. The current work is an investigation of monoclinic yttrium oxide doped with cerium synthesized by means of wet chemical precipitation at low temperature (90 C). Raman analysis and TEM experiments confirmed the formation of monoclinic phase and XPS analysis proves the presence of Ce3+ energy levels. UV experiments delivered strong absorption in the short UV region and photoluminescence experiments demonstrated the material's capability to emit in the long UV region. Surface area measurements by BET analysis established the relationship between the BET surface area and luminescence intensity. This emission range is suitable for therapeutical application especially for skin diseases which further extends the scope of the work. 2023 Elsevier Ltd and Techna Group S.r.l. -
Monitoring nyiragongo volcano using a federated cloud-based wireless sensor network
Current Nyiragongo Volcano observatory systems yield poor monitoring quality due to unpredictable dynamics of volcanic activities and limited sensing capability of existing sensors (seismometers, acoustic microphones, GPS, tilt-meter, optical thermal, and gas flux). The sensor node has limited processing capacity and memory. So if some tasks from the sensor nodes can be uploaded to the server of cloud computing then the battery life of the sensor nodes can be extended. The cloud computing can be used both for processing of aggregate query and storage of data. The two principal merits of this paper are the clear demonstration that the Cloud Computing model is a good fit with the dynamic computational requirements of Nyiragongo volcano monitoring and the novel optimization algorithm for seismic data routing. The proposed new model has been evaluated using Arduino-Atmega328 as hardware platform, Eucalyptus/Open Stack with Orchestra-Juju for Private Sensor Cloud connected to some famous public clouds such as Amazon EC2, ThingSpeak, SensorCloud and Pachube. 2017 IEEE. -
Monitoring and Controlling Data Through the Internet of Things (IOT) System: A Framework to Measure the Public Health
Associating and sharing information by means of the web between actual things, or 'things,' coordinated with sensors, programming, and different advances are known as the Internet of Things (IoT). In order to improve technology through IoT, there have been a number of important studies and investigations. This study exhibits how the Internet of Things might be utilized to screen wellbeing. In this research work, with the help of IoT based human wellbeing checking framework the information circulatory strain, beat rate, internal heat level, pulse, and other crucial signs are providing to the internet. The use of IoT for the human health monitoring system in later on future, need a very accurate assessment of risk and this is required to provide a long term information to the device. 2022 IEEE. -
MONG: An extension to galaxy clusters
The presence of dark matter (DM), though well established by indirect evidence, is yet to be observed directly. Various DM detection experiments running for several years have yielded no positive results. In view of these negative results, we had earlier proposed alternate models by postulating a minimum gravitational field strength (minimum curvature) and a minimum acceleration. These postulates led to the modified Newtonian dynamics and modified Newtonian gravity (MONG). The observed flat rotation curves of galaxies were also accounted for through these postulates. Here, we extend these postulates to galaxy clusters and model the dynamical velocity-distance curve for a typical cluster such as the Virgo cluster. The radial velocities of galaxies in the Virgo cluster are also obtained through this model. Observations show an inconsistency in the Hubble flow at a mean cluster distance of 17 Mpc, which is expected in regions of high matter density. This decrease in velocity is predicted by our model of modified gravity (MONG). The radial velocity versus distance relation for galaxies in the Virgo cluster obtained using MONG is in agreement with observations. 2022 World Scientific Publishing Company. -
Monetary policy announcement and stock price behaviour: An event study with respect to India
Monetary policy in a developing country plays a significant role in achieving the objectives of macroeconomic policies. The Central Bank formulates and implements the monetary policy in a country which in turn facilitates the increase in growth rate, manages interest rates, and money supply in the economy. The primary objective of this paper is to test the semi-strong form of Efficient Market Hypothesis in the Indian Stock Market with respect to financial services industry by conducting an event study. The monetary policy announcements made from 11th March 2016 to 30th August 2019 are taken as the events. The event study methodology is conducted on 13 financial service companies listed in NSE Financial Services Index. The Average Abnormal Return (AAR) and Cumulative Average Abnormal Return (CAAR) are estimated using the daily closing price of the sample companies and Nifty. Two sample T-statistics are used to find the significance of the returns generated. The t-values of a majority of AARs and CAARs are significant suggesting that there is a scope for generating abnormal return by the investors on the event of the monetary policy announcement. It is found that the investors are able to earn abnormal profits which indicate that the Indian stock market is not efficient in the semi-strong form due to the slow absorption of information. IJSTR 2020. -
Molecularly Imprinted Scaffold Based on poly (3-aminobenzoic acid) for Electrochemical Sensing of Vitamin B6
Inadequate or excess consumption of Vitamin B6 (Vit B6) can have ill effects on the overall well-being of humans, thereby making it necessary to control their content and composition in the food we consume. A simple sensor is fabricated in this work for Vit B6 detection based on employing an electropolymerized molecularly imprinted polymer (MIP) of 3-amino benzoic acid. The poly (3- aminobenzoic acid) (P-(3ABA)) film was electrodeposited by potentiodynamic cycling of potential with and without Vit B6 (template) on carbon fiber paper electrode (CFP). The modified working electrodes were characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Field emission scanning microscopy, Energy dispersive X-ray spectrometry, Fourier Transform Infrared spectroscopy, Optical profilometry and X-ray photon electron spectroscopy were used for characterization. Nyquist plots revealed least charge transfer resistance at MIP/CFP than other control electrodes due to the molecularly imprinted sites. Under the optimized experimental conditions the developed MIP sensor showed a linear range 0.6 ?M to 700 ?M, with a detection limit of 0.010 ?M. Also a value of the imprinting factor (? = 3.50) indicates very good selectivity of the prepared sensor towards Vit B6 detection over its structurally similar analogues in the analysis of real sample matrices. 2021 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.