46 research outputs found

    Improved Biomass Solid Fuel Based Cooking Devices and Adoptability Issues

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    ABSTRACT The planner & developer of Improved Biomass stove technologies for cooking successfully came with more energy efficient stove & significant household pollution for human health. Some studies have, so far, been made towards the identification of barriers to dissemination of Improved Biomass stove technologies for cooking in developing countries. However, most of these studies are quite general and, simultaneously, deal with several end uses of energy. An end use oriented energy\strategy is recently being advocated. In this, energy demand is disaggregated by energy end use activity, so as to highlight the technological, economic, socio-cultural and institutional issues that are relevant for each important end use. The present study is a modest attempt towards identification of barriers in dissemination of Improved Biomass stove technologies used for one of the most important end uses of energy, i.e. cooking. An effort is made to provide some insight regarding the issues and factors that are likely to affect the adoption of Improved Biomass stove technologies for cooking

    Submodular Batch Selection for Training Deep Neural Networks

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    Mini-batch gradient descent based methods are the de facto algorithms for training neural network architectures today. We introduce a mini-batch selection strategy based on submodular function maximization. Our novel submodular formulation captures the informativeness of each sample and diversity of the whole subset. We design an efficient, greedy algorithm which can give high-quality solutions to this NP-hard combinatorial optimization problem. Our extensive experiments on standard datasets show that the deep models trained using the proposed batch selection strategy provide better generalization than Stochastic Gradient Descent as well as a popular baseline sampling strategy across different learning rates, batch sizes, and distance metrics

    Characterizing the Ordinary Broad-line Type Ic SN 2023pel from the Energetic GRB 230812B

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    We report observations of the optical counterpart of the long gamma-ray burst (GRB) GRB 230812B and its associated supernova (SN) SN 2023pel. The proximity (z = 0.36) and high energy (E γ,iso ∼ 1053 erg) make it an important event to study as a probe of the connection between massive star core collapse and relativistic jet formation. With a phenomenological power-law model for the optical afterglow, we find a late-time flattening consistent with the presence of an associated SN. SN 2023pel has an absolute peak r-band magnitude of M r = −19.46 ± 0.18 mag (about as bright as SN 1998bw) and evolves on quicker timescales. Using a radioactive heating model, we derive a nickel mass powering the SN of M Ni = 0.38 ± 0.01 M ⊙ and a peak bolometric luminosity of L bol ∼ 1.3 × 1043 erg s−1. We confirm SN 2023pel’s classification as a broad-line Type Ic SN with a spectrum taken 15.5 days after its peak in the r band and derive a photospheric expansion velocity of v ph = 11,300 ± 1600 km s−1 at that phase. Extrapolating this velocity to the time of maximum light, we derive the ejecta mass M ej = 1.0 ± 0.6 M ⊙ and kinetic energy E KE = 1.3 − 1.2 + 3.3 × 10 51 erg . We find that GRB 230812B/SN 2023pel has SN properties that are mostly consistent with the overall GRB-SN population. The lack of correlations found in the GRB-SN population between SN brightness and E γ,iso for their associated GRBs across a broad range of 7 orders of magnitude provides further evidence that the central engine powering the relativistic ejecta is not coupled to the SN powering mechanism in GRB-SN systems

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Periodontal health awareness and self-perceived halitosis among various professional students of West Godavari District of Andhra Pradesh

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    Introduction: Oral health is an essential part of maintaining overall health, and poor oral health can have a profound effect on the quality of life. Among the various sections of the population present in the society, professional students include a large group of population and are believed to have a better awareness pertaining to oral health than the common population. Aim: This study aims to determine the periodontal health awareness levels along with the self-perception of halitosis among the medical, pharmacy, and engineering students in the West Godavari district of Andhra Pradesh. Materials and Methods: A descriptive cross-sectional survey was conducted in 1230 students from medical, engineering, and pharmacy professions. A self-administered 27-item structured questionnaire was used to assess periodontal health and knowledge pertaining to oral hygiene practices along with the assessment of self-perceived halitosis. Tests of the association between self-perceived halitosis and the risk factors were conducted using Chi-square test. Intergroup comparison was conducted by ANOVA and t-test. Results: Self-perceived malodor reported was 50%, 54%, and 60% by medical, pharmacy, and engineering students, respectively. The difference in the levels of overall periodontal health awareness was statistically significant among the different specialities with the highest score gained by medical students (4.1 ± 2.0), followed by the pharmacy (2.9 ± 1.6), and engineering (1.6 ± 1.3) students. Conclusions: Even though professional students do have an acceptable level of knowledge regarding oral health, the level of awareness pertaining to periodontal health in particular is lacking. Hence, there is a need to extend the horizon for oral healthcare to other professional students at an elementary level

    A systematic study on volumetric and transport properties of binary systems 1-propanol + n-hexadecane, 1-butanol + n-hexadecane and 1-propanol + ethyl oleate at different temperatures: Experimental and modeling

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    Densities (rho), viscosities (eta), speed of sounds (u) and refractive indices (n(D)) at temperature range (293.15-343.15) K with 5 K interval, for three binary mixtures (1-propanol + n-hexadecane, 1-butanol + n-hexadecane and 1-propanol + ethyl oleate), were measured at atmospheric pressure. Based on the corresponding experimental data, excess molar volume (V-E), viscosity deviation (Delta eta) and deviation in refractive index (Delta n(D)) have been calculated. Beside these properties, molar excess Gibbs free energies of activation of viscous flow (Delta*G(E)) and deviation in isentropic compressibility (Delta k(s)) were calculated from measured density, viscosity and speed of sound data. The excess/deviation functions have been fitted by Redlich-Kister equation and discussed in terms of molecular interactions existing in the mixtures. Viscosity modeling was performed using four models: UNIFAC-VISCO, ASOG-VISCO, Teja-Rice and McAllister. Experimental viscosity data have been used to determine new binary UNIFAC-VISCO and ASOG-VISCO interaction parameters and the interaction parameters for correlation models by applying some optimization technique. For all systems, positive deviations were observed for the excess molar volumes in the whole concentration range. A negative deviation and an inversion sign for the excess dynamic viscosity were observed in the systems of 1-butanol + n-hexadecane and 1-propanol + n-hexadecane, respectively, while positive deviation was observed for 1-propanol + ethyl oleate mixture. The results of viscosity modeling showed that four-body McAllister models are suitable to describe viscosities for all systems and temperatures with maximum percentage deviations (PDmax) less than 0.5%
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