48 research outputs found

    False positive probabilties for all Kepler Objects of Interest: 1284 newly validated planets and 428 likely false positives

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    We present astrophysical false positive probability calculations for every Kepler Object of Interest (KOI)---the first large-scale demonstration of a fully automated transiting planet validation procedure. Out of 7056 KOIs, we determine that 1935 have probabilities <1% to be astrophysical false positives, and thus may be considered validated planets. 1284 of these have not yet been validated or confirmed by other methods. In addition, we identify 428 KOIs likely to be false positives that have not yet been identified as such, though some of these may be a result of unidentified transit timing variations. A side product of these calculations is full stellar property posterior samplings for every host star, modeled as single, binary, and triple systems. These calculations use 'vespa', a publicly available Python package able to be easily applied to any transiting exoplanet candidate.Comment: 20 pages, 8 figures. Published in ApJ. Instructions to reproduce results can be found at https://github.com/timothydmorton/koi-fp

    Smart energy monitoring and power quality performance based evaluation of 100-kW grid tied PV system

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    Globally, the demand for energy from renewable sources is growing due to the increasing electricity consumption and the pollution of fossil fuels. The government has framed various policies to facilitate green energy generation, encouraging renewable energy source usage through PV installations in multiple sectors, including educational institutions. The primary objective of this paper is to propose a methodological approach for analysing the performance of the installed PV system on the rooftop of a university building in Tamil Nadu, India. The site selected is favourable for electricity generation from PV systems with an average global solar radiation of 5.82 kWh/m2day. Solar energy changes periodically with annual and daily variations and is not steady due to seasonal changes. The step-by-step performance assessment and the annual performance of the 100-kW solar PV system, which was instituted in 2019, with the forecasted parameters, are presented in this paper. Therefore, the assessment analysis is carried out in four phases: feasibility assessment, Energy yield assessment, Life cycle assessment, and Power quality assessment. To improve the solar PV output and efficiency, considering the solar irradiation, temperature, wind velocity, etc., PV yield is measured to evaluate the PV system\u27s energy metrics. This paper also considers the carbon credits earned, solar power generated in the location, and the payback period. The power quality assessment is carried out in this paper to test the PV plant\u27s compliance with effective grid integration

    Robotic Laser-Adaptive-Optics Imaging of 715 Kepler Exoplanet Candidates using Robo-AO

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    The Robo-AO Kepler Planetary Candidate Survey is designed to observe every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper we present the results from the 2012 observing season, searching for stars close to 715 representative Kepler planet candidate hosts. We find 53 companions, 44 of which are new discoveries. We detail the Robo-AO survey data reduction methods including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for large adaptive optics surveys. Our survey is sensitive to objects from 0.15" to 2.5" separation, with contrast ratios up to delta-m~6. We measure an overall nearby-star-probability for Kepler planet candidates of 7.4% +/- 1.0%, and calculate the effects of each detected nearby star on the Kepler-measured planetary radius. We discuss several KOIs of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are "coincident multiple" systems, with several transiting planets shared between the two stars. Finally, we detect 2.6-sigma evidence for <15d-period giant planets being 2-3 times more likely be found in wide stellar binaries than smaller close-in planets and all sizes of further-out planets.Comment: Accepted by ApJ. Minor updates & improved statistical analysis; no changes to results. 15 pages, 13 figure

    Ruddlesden-Popper chalcogenides push the limit of mechanical stiffness and glass-like thermal conductivity in crystals

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    Insulating materials featuring ultralow thermal conductivity for diverse applications also require robust mechanical properties. Conventional thinking, however, which correlates strong bonding with high atomic-vibration-mediated heat conduction, led to diverse weakly bonded materials that feature ultralow thermal conductivity and low elastic moduli. One must, therefore, search for strongly-bonded materials in which heat transport is impeded by other means. Here, we report intrinsic, glass-like, ultralow thermal conductivity and ultrahigh elastic-modulus/thermal-conductivity ratio in single-crystalline, BaZrS3-derived, Ruddlesden-Popper phases Ban+1ZrnS3n+1, n = 2, 3. Their key features are strong anharmonicity and intra-unit-cell rock-salt blocks. The latter produce strongly bonded intrinsic superlattices, impeding heat conduction by broadband reduction of phonon velocities and mean free paths and concomitant strong phonon localization. The present study initiates a paradigm of "mechanically stiff phonon glasses"

    Dynamic approach to predict pH profiles of biologically relevant buffers

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    Recently, dynamic approach has been applied to determine the steady state concentrations of multiple ionic species present in complex buffers at equilibrium. Here, we have used the dynamic approach to explicitly model the pH profiles of biologically relevant phosphate buffer and universal buffer (a mixture of three tri-protic acids such as citric acid, boric acid and phosphoric acid). The results from dynamic approach are identical to that of the conventional algebraic approach, but with an added advantage that the dynamic approach, allow for the modelling of complex buffer systems relatively easy compared to that of algebraic method

    Experience with Bortezomib in ABO-incompatible renal transplantation - А case series

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    ABO incompatible renal transplantation has gained wide spread acceptance in view of organ shortage. Acceptable Anti A and Anti B titres are achieved by various preconditioning regimens. Some patients have difficulty in achieving target titres due to refractory and rebound isoagglutinin titres. We share our experience with the use of Bortezomib in patients having moderately high base line isoagglutinin titres who had difficulty in achieving target titres during the preconditioning treatment. The use of Bortezomib can possibly reduce the number of plasma exchanges and its attendant complications

    IOT-BASED cyber security identification model through machine learning technique

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    Manual vulnerability evaluation tools produce erroneous data and lead to difficult analytical thinking. Such security concerns are exacerbated by the variety, imperfection, and redundancies of modern security repositories. These problems were common traits of producers and public vulnerability disclosures, which make it more difficult to identify security flaws through direct analysis through the Internet of Things (IoT). Recent breakthroughs in Machine Learning (ML) methods promise new solutions to each of these infamous diversification and asymmetric information problems throughout the constantly increasing vulnerability reporting databases. Due to their varied methodologies, those procedures themselves display varying levels of performance. The authors provide a method for cognitive cybersecurity that enhances human cognitive capacity in two ways. To create trustworthy data sets, initially reconcile competing vulnerability reports and then pre-process advanced embedded indicators. This proposed methodology's full potential has yet to be fulfilled, both in terms of its execution and its significance for security evaluation in application software. The study shows that the recommended mental security methodology works better when addressing the above inadequacies and the constraints of variation among cybersecurity alert mechanisms. Intriguing trade-offs are presented by the experimental analysis of our program, in particular the ensemble method that detects tendencies of computational security defects on data sources

    Acceleration of the phosphating process—the utility of galvanic coupling

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    The principle of galvanic corrosion is utilized to accelerate the rate of iron dissolution and rate of phosphating coating formation

    Hydrothermal synthesis and electrochemical properties of ZnCo2O4 microspheres

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    Zinc cobalt oxide (ZnCo2O4) microspheres are prepared at three different hydrothermal process temperatures (100 °C, 130 °C, and 160 °C) assisted with urea. XRD studies reveal the spinel face-centered cubic (Fd3m) structure of ZnCo2O4 microspheres. The optical and vibrational properties of the product are characterized by photoluminescence and FTIR studies. The strong nearband edge emission peak observed at 392 nm corresponds to the direct recombination of the exciton-exciton collision process for all three synthesized products; SEM analysis reveals the complete growth stage of spherical ZnCo2O4 microspheres at three different temperatures. The electrochemical properties of synthesized ZnCo2O4 microspheres are analyzed by cyclic voltammetry, electroimpedance spectroscopy, and galvanostatic charging and discharging studies. ZnCo2O4 microspheres (SH3–160 °C) exhibit the superior specific capacitance of 500 F/g at 0.75 A/g current density and retain their specific capacitance of 80% at current density 2 A/g. ZnCo2O4 microspheres (SH3–160 °C) may be considered as a good candidate as electrode in supercapacitor applications.This work was supported by UGC Start-Up Research Grant No. F.30-326/2016 (BSR)

    Pure and cobalt-substituted zinc-ferrite magnetic ceramics for supercapacitor applications

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    Pure and cobalt-substituted zinc ferrites were successfully synthesized employing a simple co-precipitation route. CoxZn0.04−xFe2O4 (x = 0, 0.01, 0.02) physical properties have been investigated employing comprehensive characterization studies. XRD results confirmed the cobalt substitution in zinc-ferrite magnetic ceramics. SEM analysis revealed non-uniform cluster formation with large agglomeration and more number of spherical grain nanoparticles in the range of 30–150 nm. Raman phonon vibration modes [F2g(1) + F2g(2) + A1g] revealed cubic zinc-ferrite phase and cobalt substitution. Product-predominant blue–green emission was observed in PL studies. IR results confirmed ferrite tetrahedral (~ 540–565cm−1) and octahedral sites’ (~ 428 cm−1) metal oxygen vibrations. Electrochemical studies confirmed an appreciable increase in specific capacitance of Co0.02Zn0.02Fe2O4 around 377 F/g at 10 mV/s scan rate. Cobalt substitution in zinc spinel ferrite structure revealed dominant influence on structural, optical, and electrochemical properties of the obtained product
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