22 research outputs found

    Geochemical characteristics of charnockite and high grade gneisses from Southern Peninsular Shield and their significance in crustal evolution

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    Presented here are the results of detailed investigations encompassing externsive structural mapping in the charnockite-high grade gneiss terrain of North Arcot district and the type area in Pallavaram in Tamil Nadu supported by petrography, mineral chemistry, major, minor and REE distribution patterns in various lithounits. This has helped in understanding the evolutionary history of the southern peninsular shield. A possible tectonic model is also suggested. The results of these studies are compared with similar rock types from parts of Andhra Pradesh, Kerala, Sri Lanka, Lapland and Nigeria which has brought about a well defined correlation in geochemical characteristics. The area investigated has an interbanded sequence of thick pile of charnockite and a supracrustal succession of shelf type sediments, layered igneous complex, basic and ultrabasic rocks involved in a complex structural, tectonic, igneous and metamorphic events

    Structural patterns in high grade terrain in parts of Tamil Nadu and Karnataka

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    Detailed geological mapping in parts of Tamil Nadu and Karnataka has brought out vast areas occupied by highly deformed charnockite and high grade gneisses. These areas, similar to high grade shield terrains in other parts of the world have the impress of extensive tectonic reworking multideformation and polymetamorphism and are closely associated with layered ultramafics, shelf type sediments and different igneous events. In North Arcot and Charmapuri districts of Tamil Nadu and Kollegal taluk in Mysore district in Karnataka, charnockite is intensely cofolded with a supracrustal succession of layered ultramafics, pyroxene granulite, pink granolites, magnetite quartzite and khondalites. These areas have undergone five phases of deformation, five generations of basic dyke activities, four phases of migmatisation and two periods of metallogeny. Geochronological data ranges from 2900 m.y. to 750 m.y. In working out the tectanostratigraphy of the above areas the basic dykes of different generations have served as major time markers. In addition, the persistent strike continuity of linear bands of pyroxene granulite, pink granolite and magnetite quartzite has been of great utility in using them as structural markers for bringing out the complex structural history in these areas

    High Performance Flower Shape Manganese Oxide for Asymmetric Supercapacitor Device

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    A flower shaped manganese oxide have been synthesized using simple and low temperature procedure. Subsequently, an asymmetric supercapacitor is fabricated using manganese oxide and activated carbon as positive and negative electrode in aqueous electrolyte. The supercapacitor was measured at open windows 2.0 V showing energy density of 25.79 Wh/kg at power density of 100 W/kg. The supercapacitor stability was tested at 3 A/g and showing specific capacitance retention of 95% after 850 cycle

    Fractal dimension: analyzing its potential as a neuroimaging biomarker for brain tumor diagnosis using machine learning

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    Purpose: The main purpose of this study was to comprehensively investigate the potential of fractal dimension (FD) measures in discriminating brain gliomas into low-grade glioma (LGG) and high-grade glioma (HGG) by examining tumor constituents and non-tumorous gray matter (GM) and white matter (WM) regions.Methods: Retrospective magnetic resonance imaging (MRI) data of 42 glioma patients (LGG, n = 27 and HGG, n = 15) were used in this study. Using MRI, we calculated different FD measures based on the general structure, boundary, and skeleton aspects of the tumorous and non-tumorous brain GM and WM regions. Texture features, namely, angular second moment, contrast, inverse difference moment, correlation, and entropy, were also measured in the tumorous and non-tumorous regions. The efficacy of FD features was assessed by comparing them with texture features. Statistical inference and machine learning approaches were used on the aforementioned measures to distinguish LGG and HGG patients.Results: FD measures from tumorous and non-tumorous regions were able to distinguish LGG and HGG patients. Among the 15 different FD measures, the general structure FD values of enhanced tumor regions yielded high accuracy (93%), sensitivity (97%), specificity (98%), and area under the receiver operating characteristic curve (AUC) score (98%). Non-tumorous GM skeleton FD values also yielded good accuracy (83.3%), sensitivity (100%), specificity (60%), and AUC score (80%) in classifying the tumor grades. These measures were also found to be significantly (p < 0.05) different between LGG and HGG patients. On the other hand, among the 25 texture features, enhanced tumor region features, namely, contrast, correlation, and entropy, revealed significant differences between LGG and HGG. In machine learning, the enhanced tumor region texture features yielded high accuracy, sensitivity, specificity, and AUC score.Conclusion: A comparison between texture and FD features revealed that FD analysis on different aspects of the tumorous and non-tumorous components not only distinguished LGG and HGG patients with high statistical significance and classification accuracy but also provided better insights into glioma grade classification. Therefore, FD features can serve as potential neuroimaging biomarkers for glioma

    Multifunctional nanowires and hierarchical 3D nanostructures of material composites for energy storage

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    Composites of functional materials have long been synthesized for achieving enhanced physical and chemical properties. In this era of energy intensive electronics and electric vehicles, energy storage devices utilising composite materials could offer improved performance at a lower cost. Furthermore, if the composite materials are synthesized in one-dimensional morphology at a nano level, conductivity and thus electrical properties could be multiplied. A range of materials with different functionalities have been synthesized by our group recently; as a typical example synthesis of a composite nanowire containing NiO and CuO for supercapacitive energy storage is detailed in this paper and compared the performance of the composite wires with its component binary wires. The materials were synthesized by electrospinning technique and characterized for their structure, microstructure, surface properties and electrochemical properties. The results shows that a composite wire containing materials for similar electrical conductivity would lead to improved charge storage performance than their single component counterparts

    Retinal Nerve Fiber Layer Thickness in Patients with Schizophrenia and Its Relation with Cognitive Impairment

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    Background: Schizophrenia is a chronic severe mental illness with heterogeneous clinical presentation, course, and outcome. Cognitive impairment is one of its core features. Retinal nerve fiber layer (RNFL) imaging using OCT (optical coherence tomography) could provide easy access for in vivo imaging of the retina, rendering it as a “window to the brain.” Studies done on schizophrenia have shown RNFL thinning. This study attempts to look into the association between cognitive impairment, disease duration, and RNFL abnormality in patients with schizophrenia using OCT. Methods: Patients diagnosed with schizophrenia meeting DSM 5 (Diagnostic and Statistical Manual of Mental Disorders) criteria and who were confirmed to be in remission for at least six months clinically and scoring less than three on PANSS-8 (positive and negative symptom scale-8) remission scale were included. They were administered the Montreal Cognitive Assessment Scale (MoCA) for cognitive assessment. RNFL measures were taken using spectral domain-OCT. Variables were compared using Pearson’s correlation test, one-way ANOVA test, and independent t -test as appropriate. Results: A total of 36 patients were studied. MoCA scores and RNFL thickness showed a positive correlation. Patients with schizophrenia had reduced average RNFL thickness and reduced RNFL thickness in superior, inferior, and temporal quadrants. Average RNFL thickness, Superior and inferior quadrant RNFL thickness showed a positive correlation with MoCA scores. No correlation was obtained between macular volume, macular thickness, duration of illness, and MoCA scores. Conclusion: Patients with schizophrenia have reduced average RNFL thickness. Patients with low MoCA scores have RNFL thinning

    Supercapacitor Electrodes Delivering High Energy and Power Densities

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    Considerable progress has been achieved in developing supercapacitor materials with desirable charge storage properties; however, uniting energy density (ES) and power density (PS) in a single device is an elusive issue. We have explored diverse range of materials and structures such as (i) activated carbon from bio-resources, (ii) ceramic electrochemical materials as nanoparticles, nanowires, and nanoribbons, and (iii) layered materials to overcome this issue. An ES of ∼52.6 Wh kg-1 @ PS of ∼15000 W kg-1 is delivered using nanowire nanocomposites based device which appear to be the best ever achieved in supercapacitor charge storage mode employing aqueous alkaline electrolytes
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