183 research outputs found

    Delineating Knowledge Domains in Scientific Domains in Scientific Literature using Machine Learning (ML)

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    The recent years have witnessed an upsurge in the number of published documents. Organizations are showing an increased interest in text classification for effective use of the information. Manual procedures for text classification can be fruitful for a handful of documents, but the same lack in credibility when the number of documents increases besides being laborious and time-consuming. Text mining techniques facilitate assigning text strings to categories rendering the process of classification fast, accurate, and hence reliable. This paper classifies chemistry documents using machine learning and statistical methods. The procedure of text classification has been described in chronological order like data preparation followed by processing, transformation, and application of classification techniques culminating in the validation of the results

    Efficiency Enhancement by Live Sun Tracking for Solar PV System

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    The solar Photovoltaic system is now being adopted on a large scale as well as small house hold systems for general utilities. The conversion of solar energy into electrical energy is largely affected by the angle and direction of the solar panels. As the direct incident light is only light which is useful and produces electrical energy. The placing of solar panels at exact angle & direction according to motion of sun can maximize the overall efficiency of the system. This research work implements the solar tracking system according to sun’s motion from east to west. The implementation of such a tracking system with small microcontroller controlled motors and sensors can be beneficial

    Public libraries in Varanasi (Uttar Pradesh), India: an explorative study

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    The main purpose of this paper is to explore the current status of public libraries of Varanasi. A structured questionnaire was designed and personally distributed to 100 respondents over a period of seven months for the study. Responses present a dismal outlook of the libraries. Financial deficit and lack of computers, infrastructure and staff have stagnated the development of these libraries. These libraries continue to stand the same way as they stood 60 years before

    Public libraries in Varanasi (Uttar Pradesh), India: an explorative study

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    The main purpose of this paper is to explore the current status of public libraries of Varanasi. A structured questionnaire was designed and personally distributed to 100 respondents over a period of seven months for the study. Responses present a dismal outlook of the libraries. Financial deficit and lack of computers, infrastructure and staff have stagnated the development of these libraries. These libraries continue to stand the same way as they stood 60 years before

    Microwave Absorption Performance of Graphene Nanoplatelets Dispersed SiC

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    Microwave absorption performance of graphene nanoplatelets based SiC composites have been studied in the present work. Graphene nanoplatelets were dispersed at varying weight fractions viz. 0.5, 1, 2, 2.5 and 3 wt.% in SiC using ultrasonication and ball milling methods. Microwave attenuation behaviour of the prepared composites have been observed in the 2-18 GHz range. The results reflect that dispersion of graphene in SiC proves to be very instrumental in attenuating the incident microwave signals translating into enhanced absorption. The enhancement in the microwave absorption performance is due to the presence of conductive graphene nanoplatelets which is very instrumental in promoting conduction and polarisation losses in the composite translating into enhanced absorption. For 3 wt.% graphene nanoplatelets dispersion in SiC, the value of reflection loss (RL) was obtained as -38.67 dB at 14.67 GHz frequency for 2.2 mm thickness with the corresponding bandwidth of 5 GHz

    Oxidation of benzoin catalyzed by oxovanadium (IV) schiff base complexes

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    BACKGROUND: The oxidative transformation of benzoin to benzil has been accomplished by the use of a wide variety of reagents or catalysts and different reaction procedures. The conventional oxidizing agents yielded mainly benzaldehyde or/and benzoic acid and only a trace amount of benzil. The limits of practical utilization of these reagents involves the use of stoichiometric amounts of corrosive acids or toxic metallic reagents, which in turn produce undesirable waste materials and required high reaction temperatures. In recent years, vanadium complexes have attracted much attention for their potential utility as catalysts for various types of reactions. RESULTS: Active and selective catalytic systems of new unsymmetrical oxovanadium(IV) Schiff base complexes for the oxidation of benzoin is reported. The Schiff base ligands are derived between 2-aminoethanol and 2-hydroxy-1- naphthaldehyde (H2L1) or 3-ethoxy salicylaldehyde (H2L3); and 2-aminophenol and 3-ethoxysalicylaldehyde (H2L2) or 2-hydroxy-1-naphthaldehyde (H2L4). The unsymmetrical Schiff bases behave as tridentate dibasic ONO donor ligands. Reaction of these Schiff base ligands with oxovanadyl sulphate afforded the mononuclear oxovanadium(IV) complexes (VIVOLx.H2O), which are characterized by various physico-chemical techniques. The catalytic oxidation activities of these complexes for benzoin were evaluated using H2O2 as an oxidant. The best reaction conditions are obtained by considering the effect of solvent, reaction time and temperature. Under the optimized reaction conditions, VOL4 catalyst showed high conversion (>99%) with excellent selectivity to benzil (~100%) in a shorter reaction time compared to the other catalysts considered. CONCLUSION: Four tridentate ONO type Schiff base ligands were synthesized. Complexation of these ligands with vanadyl(IV) sulphate leads to the formation of new oxovanadium(IV) complexes of type VIVOL.H2O. Elemental analyses and spectral data of the free ligands and their oxovanadium(IV) complexes were found to be in good agreement with their structures, indicating high purity of all the compounds. Oxovanadium complexes were screened for the oxidation of benzoin to benzil using H2O2 as oxidant. The effect of time, solvent and temperature were optimized to obtain maximum yield. The catalytic activity results demonstrate that these catalytic systems are both highly active and selective for the oxidation of benzoin under mild reaction conditions.Web of Scienc

    A Dual Receptor Crosstalk Model of G-Protein-Coupled Signal Transduction

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    Macrophage cells that are stimulated by two different ligands that bind to G-protein-coupled receptors (GPCRs) usually respond as if the stimulus effects are additive, but for a minority of ligand combinations the response is synergistic. The G-protein-coupled receptor system integrates signaling cues from the environment to actuate cell morphology, gene expression, ion homeostasis, and other physiological states. We analyze the effects of the two signaling molecules complement factors 5a (C5a) and uridine diphosphate (UDP) on the intracellular second messenger calcium to elucidate the principles that govern the processing of multiple signals by GPCRs. We have developed a formal hypothesis, in the form of a kinetic model, for the mechanism of action of this GPCR signal transduction system using data obtained from RAW264.7 macrophage cells. Bayesian statistical methods are employed to represent uncertainty in both data and model parameters and formally tie the model to experimental data. When the model is also used as a tool in the design of experiments, it predicts a synergistic region in the calcium peak height dose response that results when cells are simultaneously stimulated by C5a and UDP. An analysis of the model reveals a potential mechanism for crosstalk between the Gαi-coupled C5a receptor and the Gαq-coupled UDP receptor signaling systems that results in synergistic calcium release
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