60 research outputs found

    Assessment of magnetic data for landfill characterization by means of a probabilistic approach

    Get PDF
    The sustainable vision of the Dynamic Landfill Management (DLM) deals not only with present but also with long-term waste management. In this context, DLM enhances the environmental assessment of landfills after closure as well as the recovery of materials and energy resources, for which, a proper characterization is required. To this end, geophysical methods have demonstrated their suitability for landfill exploration, characterization and monitoring. Due to the complexity of these sites and challenges in data acquisition and/or processing, the use of multiple methods is the best approach for landfill investigations. In this work, we used multiple geophysical methods, co-located with several trial pits and boreholes, to estimate the structure of a waste disposal site located in a quarry, and to better delineate the underlying geology composed of limestone. We applied electrical resistivity tomography (ERT), time-domain induced polarization (IP), H/V spectral ratio from microtremor records and magnetometry. We made a structural joint interpretation using the different datasets and the ground truth data. First, the ERT and IP data were individually inverted, and a first structural model was derived. Afterwards, we followed a parametric analysis of the H/V data to corroborate the thickness of some layers at the position of the seismic stations. Then, this model was used to compute synthetic magnetic data and by comparing them with the observed total field magnetic anomalies, a refined model was produced. We evaluated the improvement of including magnetic modelling by using a probabilistic approach previously reported. This approach is based on the computation of conditional probabilities by comparing the inverted models with the co-located data from trial pits and boreholes. Overall, we delineated the lateral and vertical extension of the waste body, the distribution of ash and lime deposits and estimated the upper limit structure of the bedrock

    Evidence for mass-dependent peculiar velocities in compact object binaries: Towards better constraints on natal kicks

    Full text link
    We compile a catalogue of low-mass and high-mass X-ray binaries, some recently reported binaries that likely host a neutron star (NS) or a black hole (BH), and binary pulsars (a pulsar and a non-degenerated companion) that have measured systemic radial velocities (γ\gamma). Using Gaia and radio proper motions together with γ\gamma, we integrate their Galactic orbits and infer their post-supernova (post-SN) 3D peculiar velocities (vpecz=0v_\mathrm{pec}^{z=0} at Galactic plane crossing); these velocities bear imprint of natal kicks that compact objects received at birth. With the sample totalling 85 objects, we model the overall distribution of vpecz=0v_\mathrm{pec}^{z=0} and find a two-component Maxwellian distribution with a low- (σv21km s1\sigma_v \approx 21\,\mathrm{km~s^{-1}}) and a high-velocity (σv107km s1\sigma_v \approx 107\,\mathrm{km~s^{-1}}) component. A further comparison between distributions of binary subgroups suggests that binaries hosting high-mass donors/luminous companions mostly have vpecz=0100km s1v_\mathrm{pec}^{z=0}\lesssim 100\,\mathrm{km~s^{-1}}, while binaries with low-mass companions exhibit a broader distribution that extends up to 400km s1\sim 400\,\mathrm{km~s^{-1}}. We also find significant anti-correlations of vpecz=0v_\mathrm{pec}^{z=0} with binary total mass (MtotM_\mathrm{tot}) and orbital period (PorbP_\mathrm{orb}), at over 99% confidence. Specifically, our fit suggests vpecz=0Mtot0.5v_\mathrm{pec}^{z=0}\propto M_\mathrm{tot}^{-0.5} and vpecz=0Porb0.2v_\mathrm{pec}^{z=0}\propto P_\mathrm{orb}^{-0.2}. Discussions are presented on possible interpretation of the correlations in the context of kinematics and possible biases. The sample should enable a range of follow-up studies on compact object binary kinematics and evolution.Comment: 26 pages, 14 figures, 8 tables, resubmitted to MNRAS after first revisio

    Formation of Long-Lived Color Centers for Broadband Visible Light Emission in Low-Dimensional Layered Perovskites.

    Get PDF
    We investigate the origin of the broadband visible emission in layered hybrid lead-halide perovskites and its connection with structural and photophysical properties. We study ⟨001⟩ oriented thin films of hexylammonium (HA) lead iodide, (C6H16N)2PbI4, and dodecylammonium (DA) lead iodide, (C12H28N)2PbI4, by combining first-principles simulations with time-resolved photoluminescence, steady-state absorption and X-ray diffraction measurements on cooling from 300 to 4 K. Ultrafast transient absorption and photoluminescence measurements are used to track the formation and recombination of emissive states. In addition to the excitonic photoluminescence near the absorption edge, we find a red-shifted, broadband (full-width at half-maximum of about 0.4 eV), emission band below 200 K, similar to emission from ⟨110⟩ oriented bromide 2D perovskites at room temperature. The lifetime of this sub-band-gap emission exceeds that of the excitonic transition by orders of magnitude. We use X-ray diffraction measurements to study the changes in crystal lattice with temperature. We report changes in the octahedral tilt and lattice spacing in both materials, together with a phase change around 200 K in DA2PbI4. DFT simulations of the HA2PbI4 crystal structure indicate that the low-energy emission is due to interstitial iodide and related Frenkel defects. Our results demonstrate that white-light emission is not limited to ⟨110⟩ oriented bromide 2D perovskites but a general property of this class of system, and highlight the importance of defect control for the formation of low-energy emissive sites, which can provide a pathway to design tailored white-light emitters

    IGF-I abuse in sport

    No full text
    It is widely believed that growth hormone (GH) is abused by athletes for its anabolic and lipolytic effects. Many of the physiological effects of GH are mediated by the production of insulin-like growth factor-I (IGF-I). Both GH and IGF-I appear on the World Anti-Doping Agency list of prohibited substances. Little is known, however, about the prevalence of abuse with exogenous IGF-I. IGF-I has effects on carbohydrate, lipid and protein metabolism and some of these actions could prove beneficial to competitive athletes. No studies have demonstrated a positive effect of IGF-I on physical performance in healthy individuals but this has not yet been studied in appropriately designed trials. Two pharmaceutical preparations of IGF-I have recently become available for the treatment of growth disorders in children. This availability is likely to increase the prevalence of IGF-I abuse. Combining IGF-I with its binding protein IGFBP-3 in one preparation has the potential to reduce the side-effect profile but the adverse effects of long term IGF-I abuse are currently unknown. Detection of abuse with IGF-I is a major challenge for anti-doping authorities. It is extremely difficult to distinguish the exogenous recombinant form of the hormone from endogenously-produced IGF-I. One approach currently being investigated is based on measuring markers of GH and IGF-I action. This has already proved successful in the fight against GH abuse and, it is hoped, will subsequently lead to a similar test for detection of IGF-I abuse.<br/

    Evidence for mass-dependent peculiar velocities in compact object binaries: towards better constraints on natal kicks

    No full text
    We compile a catalogue of low-mass and high-mass X-ray binaries, some recently reported binaries that likely host a neutron star (NS) or a black hole (BH), and binary pulsars (a pulsar and a non-degenerated companion) that have measured systemic radial velocities (γ). Using Gaia and radio proper motions together with γ, we integrate their Galactic orbits and infer their post-supernova (post-SN) 3D peculiar velocities (

    The regulatory power of business norms: a call for a new research agenda.

    No full text
    What role do international business norms play in regulating the behavior of firms? Despite growing acceptance of the constructivist claim that norms play an important role in international life and an increased interest in private authority by international relations (IR) scholars, surprisingly little research in the field has explored the extent or mechanisms by which norms influence the behavior of firms. I argue this oversight has more to do with the bias in political science against viewing firms as social or socializable institutions than with the applicability of constructivist theory to firms or markets. To make this argument I examine the spread of sustainability norms across transnational business networks and illustrate how theories of socialization developed by IR constructivist scholars can help explain the rapid spread of these norms and the effects they have on corporate environmental governance. The paper ends with a call for more research on the effects of international business norms and makes several suggestions for how to counteract the bias in political science against doing so
    corecore