103 research outputs found

    Experimental and computational approaches to study the high temperature thermoelectric properties of novel topological semimetal CoSi

    Full text link
    Here, we study the thermoelectric properties of topological semimetal CoSi in the temperature range 300−800300-800 K by using combined experimental and density functional theory (DFT) based methods. CoSi is synthesized using arc melting technique and the Rietveld refinement gives the lattice parameters of a = b = c = 4.445 {\AA}. The measured values of Seebeck coefficient (S) shows the non-monotonic behaviour in the studied temperature range with the value of ∌−\sim-81 ÎŒ\muV/K at room temperature. The ∣S∣|S| first increases till 560 K (∌−\sim-93 ÎŒ\muV/K) and then decreases up to 800 K (∌−\sim-84 ÎŒ\muV/K) indicating the dominating n-type behaviour in the full temperature range. The electrical conductivity, σ\sigma (thermal conductivity, Îș\kappa) shows the monotonic decreasing (increasing) behaviour with the values of ∌\sim5.2×105\times 10^{5} (12.1 W/m-K) and ∌\sim3.6×105\times 10^{5} (14.2 W/m-K) Ω−1m−1\Omega^{-1}m^{-1} at 300 K and 800 K, respectively. The Îș\kappa exhibits the temperature dependency as, Îș∝T0.16\kappa \propto T^{0.16}. The DFT based Boltzmann transport theory is used to understand these behaviour. The multi-band electron and hole pockets appear to be mainly responsible for deciding the temperature dependent transport behaviour. Specifically, the decrease in the ∣S∣|S| above 560 K and change in the slope of σ\sigma around 450 K are due to the contribution of thermally generated charge carriers from the hole pockets. The temperature dependent relaxation time is computed which shows temperature dependency of 1/T0.351/T^{0.35}. Present study suggests that electronic band-structure obtained from DFT provides reasonably good estimate of the transport coefficients of CoSi in the high temperature region of 300−800300-800 K

    Rhizosphere of rice plants harbor bacteria with multiple plant growth promoting features

    Get PDF
    114 diazotrophic bacteria from the rice rhizosphere of five districts of Eastern Uttar Pradesh (India) were isolated and screened for plant growth promoting (PGP) activities employing standard microbiological and biochemical techniques. All these isolates showed nitrogenase activity in the range of 0.23 to 1.72 ÎŒmol C2H4 mg-1 protein h-1. Further analysis showed that 84 (73.68%) isolates were Indole-3-acetic acid (IAA) producer; the value of IAA production ranged from 10.1 to 353.0 ÎŒg IAA mg-1 protein. IAA production occurred solely in the medium supplemented with tryptophan. P solubilization activity was observed in 28 (24.56%) isolates, the activity being in the range of 38.50 to 321.0 P released ÎŒg mg-1 protein. 45 (39.46%) isolates were capable of producing siderophore, the range of production being 4.50 to 223.26 ÎŒg mg-1 protein. Analysis of molecular diversity was made by amplified ribosomal DNA restriction analysis (ARDRA) and denaturating gradient gel electrophoresis (DGGE), which exhibited distinct differences among all the isolates. Of the 114 isolates, twenty one (21) isolates showed multiple plant growth promoting traits and were potent in terms of PGP activities. These isolates were identified on the basis of 16S rDNA sequencing and belonged to the genera Pantoea, Bacillus, Microbacterium, Pseudomonas, Sphingomonas, Ancylobacter, Enterobacter, Advenella, Îł-proteobacterium strain VA3S1, Rhizobium and Agrobacterium. Findings of this study suggest that certain isolates may be exploited for developing a potential source of biofertilizer.Key words: Plant growth promoting rhizobacteria, N2 fixation, amplified ribosomal DNA restriction analysis, indole-3-acetic acid, siderophore, denaturing gradient gel electrophoresis, temperature gradient gel electrophoresi

    Collapse risk and residual drift performance of steel buildings using post-tensioned MRFs and viscous dampers in near-fault regions

    Get PDF
    The potential of post-tensioned self-centering moment-resisting frames (SC-MRFs) and viscous dampers to reduce the collapse risk and improve the residual drift performance of steel buildings in near-fault regions is evaluated. For this purpose, a prototype steel building is designed using different seismic-resistant frames, i.e.: moment-resisting frames (MRFs); MRFs with viscous dampers; SC-MRFs; and SC-MRFs with viscous dampers. The frames are modeled in OpenSees where material and geometrical nonlinearities are taken into account as well as stiffness and strength deterioration. A database of 91 near-fault, pulse-like ground motions with varying pulse periods is used to conduct incremental dynamic analysis (IDA), in which each ground motion is scaled until collapse occurs. The probability of collapse and the probability of exceeding different residual story drift threshold values are calculated as a function of the ground motion intensity and the period of the velocity pulse. The results of IDA are then combined with probabilistic seismic hazard analysis models that account for near-fault directivity to assess and compare the collapse risk and the residual drift performance of the frames. The paper highlights the benefit of combining the post-tensioning and supplemental viscous damping technologies in the near-source. In particular, the SC-MRF with viscous dampers is found to achieve significant reductions in collapse risk and probability of exceedance of residual story drift threshold values compared to the MRF. © 2016 Springer Science+Business Media Dordrech

    Effect of sonic versus ultrasonic activation on aqueous solution penetration in root canal dentin.

    Full text link

    Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 1: The LBNF and DUNE Projects

    Get PDF
    This document presents the Conceptual Design Report (CDR) put forward by an international neutrino community to pursue the Deep Underground Neutrino Experiment at the Long-Baseline Neutrino Facility (LBNF/DUNE), a groundbreaking science experiment for long-baseline neutrino oscillation studies and for neutrino astrophysics and nucleon decay searches. The DUNE far detector will be a very large modular liquid argon time-projection chamber (LArTPC) located deep underground, coupled to the LBNF multi-megawatt wide-band neutrino beam. DUNE will also have a high-resolution and high-precision near detector

    The Single-Phase ProtoDUNE Technical Design Report

    Get PDF
    ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single-phase LArTPC detector to be built to date. It's technical design is given in this report

    The DUNE Far Detector Interim Design Report, Volume 3: Dual-Phase Module

    Get PDF
    The DUNE IDR describes the proposed physics program and technical designs of the DUNE far detector modules in preparation for the full TDR to be published in 2019. It is intended as an intermediate milestone on the path to a full TDR, justifying the technical choices that flow down from the high-level physics goals through requirements at all levels of the Project. These design choices will enable the DUNE experiment to make the ground-breaking discoveries that will help to answer fundamental physics questions. Volume 3 describes the dual-phase module's subsystems, the technical coordination required for its design, construction, installation, and integration, and its organizational structure

    The DUNE Far Detector Interim Design Report, Volume 2: Single-Phase Module

    Get PDF
    The DUNE IDR describes the proposed physics program and technical designs of the DUNE far detector modules in preparation for the full TDR to be published in 2019. It is intended as an intermediate milestone on the path to a full TDR, justifying the technical choices that flow down from the high-level physics goals through requirements at all levels of the Project. These design choices will enable the DUNE experiment to make the ground-breaking discoveries that will help to answer fundamental physics questions. Volume 2 describes the single-phase module's subsystems, the technical coordination required for its design, construction, installation, and integration, and its organizational structure

    The DUNE Far Detector Interim Design Report Volume 1: Physics, Technology and Strategies

    Get PDF
    The DUNE IDR describes the proposed physics program and technical designs of the DUNE Far Detector modules in preparation for the full TDR to be published in 2019. It is intended as an intermediate milestone on the path to a full TDR, justifying the technical choices that flow down from the high-level physics goals through requirements at all levels of the Project. These design choices will enable the DUNE experiment to make the ground-breaking discoveries that will help to answer fundamental physics questions. Volume 1 contains an executive summary that describes the general aims of this document. The remainder of this first volume provides a more detailed description of the DUNE physics program that drives the choice of detector technologies. It also includes concise outlines of two overarching systems that have not yet evolved to consortium structures: computing and calibration. Volumes 2 and 3 of this IDR describe, for the single-phase and dual-phase technologies, respectively, each detector module's subsystems, the technical coordination required for its design, construction, installation, and integration, and its organizational structure
    • 

    corecore