578 research outputs found

    Model signatures and aridity indices enhance the accuracy of water balance estimations in a data-scarce Eastern Mediterranean catchment

    Get PDF
    Study region: Wadi Faria catchment, Palestine. Study focus: The upper part of the Faria catchment (139 km2) is a typical semi-arid karst catchment in the Eastern Mediterranean, where, up to recently, data availability has hindered the accurate assessment of renewable water resources. Newly available six-year time-series of rainfall and runoff data, combined with thorough field campaigns, enabled the application of the distributed TRAIN-ZIN watershed model. The model was constrained using seven hydrological signatures derived from the available time-series. New hydrological insights for the region: We found that the mean annual actual evapotranspiration was about 70% of precipitation, recharge was about 30% and natural runoff (excluding baseflow) 1%. Aggregated model results also supported aridity indicators that show the presence of Infiltration Excess (Hortonian) Overland Flow, as well as the importance of indirect groundwater recharge and evaporation from soil during dry months. In total, maximum annual water availability was of the same order of magnitude as actual demand estimates (23 MCM). However, high spatial and inter-annual variability, and the presence of karst features suggest that water resources in the region are highly vulnerable

    Elucidating Conformation and Hydrogen-Bonding Motifs of Reactive Thiourea Intermediates

    Get PDF

    Watching videos together in social Virtual Reality: An experimental study on user’s QoE

    Get PDF
    In this paper, we describe a user study in which pairs of users watch a video trailer and interact with each other, using two social Virtual Reality (sVR) systems, as well as in a face-to-face condition. The sVR systems are: Facebook Spaces, based on puppet-like customized avatars, and a video-based sVR system using photo-realistic virtual user representations. We collect subjective and objective data to analyze users’ Quality of Experience (QoE) and compare their interaction in VR to that observed during the real-life scenario. Our results show that the experience delivered by the video-based sVR system is comparable with real-life settings, while the puppet-based avatars limit the perceived q

    Defect-control of conventional and anomalous electron transport at complex oxide interfaces

    Get PDF
    Using low-temperature electrical measurements, the interrelation between electron transport, magnetic properties, and ionic defect structure in complex oxide interface systems is investigated, focusing on NdGaO3/SrTiO3 (100) interfaces. Field-dependent Hall characteristics (2–300 K) are obtained for samples grown at various growth pressures. In addition to multiple electron transport, interfacial magnetism is tracked exploiting the anomalous Hall effect (AHE). These two properties both contribute to a nonlinearity in the field dependence of the Hall resistance, with multiple carrier conduction evident below 30 K and AHE at temperatures ≲10  K. Considering these two sources of nonlinearity, we suggest a phenomenological model capturing the complex field dependence of the Hall characteristics in the low-temperature regime. Our model allows the extraction of the conventional transport parameters and a qualitative analysis of the magnetization. The electron mobility is found to decrease systematically with increasing growth pressure. This suggests dominant electron scattering by acceptor-type strontium vacancies incorporated during growth. The AHE scales with growth pressure. The most pronounced AHE is found at increased growth pressure and, thus, in the most defective, low-mobility samples, indicating a correlation between transport, magnetism, and cation defect concentratio

    Optical Imaging of Large Gyroid Grains in Block Copolymer Templates by Confined Crystallization.

    Get PDF
    Block copolymer (BCP) self-assembly is a promising route to manufacture functional nanomaterials for applications from nanolithography to optical metamaterials. Self-assembled cubic morphologies cannot, however, be conveniently optically characterized in the lab due to their structural isotropy. Here, the aligned crystallization behavior of a semicrystalline-amorphous polyisoprene-b-polystyrene-b-poly(ethylene oxide) (ISO) triblock terpolymer was utilized to visualize the grain structure of the cubic microphase-separated morphology. Upon quenching from a solvent swollen state, ISO first self-assembles into an alternating gyroid morphology, in the confinement of which the PEO crystallizes preferentially along the least tortuous pathways of the single gyroid morphology with grain sizes of hundreds of micrometers. Strikingly, the resulting anisotropic alignment of PEO crystallites gives rise to a unique optical birefringence of the alternating gyroid domains, which allows imaging of the self-assembled grain structure by optical microscopy alone. This study provides insight into polymer crystallization within a tortuous three-dimensional network and establishes a useful method for the optical visualization of cubic BCP morphologies that serve as functional nanomaterial templates.This research was supported through the Swiss National Science Foundation through grant numbers 163220 (U.S.) and 168223 (B.D.W.), the National Center of Competence in Research Bio-Inspired Materials (U.S., B.D.W, I.G.), the Adolphe Merkle Foundation (B.D.W., U.S., I.G.), the Engineering and Physical Sciences Research Council through the Cambridge NanoDTC EP/G037221/1, EP/L027151/1, EP/N016920/1, and EP/G060649/1 (R.D., J.A.D., J.J.B.), and ERC LINASS 320503 (J.J.B.). This project has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 706329/cOMPoSe (I.G.). Y.G. and U.W. thank the National Science Foundation (DMR-1409105) for financial support. Part of the work was conducted at beamline D1 at the Cornell High Energy Synchrotron Source (CHESS); CHESS is supported by the NSF and NIH/NIGMS via NSF award DMR-1332208. We also thank Diamond Light Source for access to beamline I22 (SM13448) that contributed to the results presented here

    Polymer-templated mesoporous lithium titanate microspheres for high-performance lithium batteries

    Get PDF
    The spinel Li4Ti5O12 (LTO) is a promising lithium ion battery anode material with the potential to supplement graphite as an industry standard, but its low electrical conductivity and Li–ion diffusivity need to be overcome. Here, mesoporous LTO microspheres with carbon-coatings were formed by phase separation of a homopolymer from microphase-separated block copolymers of varying molar masses containing sol–gel precursors. Upon heating the composite underwent a sol–gel condensation reaction followed by the eventual pyrolysis of the polymer templates. The optimised mesoporous LTO microspheres demonstrated an excellent electrochemical performance with an excellent specific discharge capacity of 164 mA h g−1, 95% of which was retained after 1000 cycles at a C-rate of 10

    Phase segregation in supramolecular polymers based on telechelics synthesized via multicomponent reactions

    Get PDF
    The properties of supramolecular polymers in the solid state are strongly dependent on the binding strength of the supramolecular motifs used; however, It has been previously shown that the nanostructure of supramolecular polymers plays an equally important role. Supramolecular polymers are commonly synthesized via end-group functionalization of low-glass transition telechelics with supramolecular units. In these systems, the binding motifs segregate from the soft telechelic backbone and form a hydrogen bonded crystalline hard phase that provides physical cross-links. To date, the reported synthetic approaches do not permit the introduction of a wide variety of supramolecular units with low synthetic effort, which would facilitate studying the structure-property relationships. The use of the Passerini and Ugi multicomponent reactions to synthesize various poly(ethylene-co-butylene) telechelics with diverse amide end-groups is reported. The thermal properties of the supramolecular polymers obtained through their solid-state assembly are investigated and their nanophase- segregation is studied, which is dictated by the end-group volume fraction and the amide–amide hydrogen bonding

    UV radiation enhanced oxygen vacancy formation caused by the PLD plasma plume

    Get PDF
    Pulsed Laser Deposition is a commonly used non-equilibrium physical deposition technique for the growth of complex oxide thin films. A wide range of parameters is known to influence the properties of the used samples and thin films, especially the oxygen-vacancy concentration. One parameter has up to this point been neglected due to the challenges of separating its influence from the influence of the impinging species during growth: the UV-radiation of the plasma plume. We here present experiments enabled by a specially designed holder to allow a separation of these two influences. The influence of the UV-irradiation during pulsed laser deposition on the formation of oxygen-vacancies is investigated for the perovskite model material SrTiO3. The carrier concentration of UV-irradiated samples is nearly constant with depth and time. By contrast samples not exposed to the radiation of the plume show a depth dependence and a decrease in concentration over time. We reveal an increase in Ti-vacancy–oxygen-vacancy-complexes for UV irradiated samples, consistent with the different carrier concentrations. We find a UV enhanced oxygen-vacancy incorporation rate as responsible mechanism. We provide a complete picture of another influence parameter to be considered during pulsed laser depositions and unravel the mechanism behind persistent-photo-conductivity in SrTiO3
    • …
    corecore