Abstract: Human activities related to urbanization and industrialization have established a vast territory of urban soil worldwide. On traditional soil maps, urban and industrial areas usually appear as blind spots as they were beyond the interest of national soil survey campaigns. Furthermore, these soil maps are likely already outdated with respect to urban soil due to rapid urban expansion in recent decades. This research aims to evaluate the use of land cover data to estimate the urban soil information gap considering the highly urbanized region of Flanders, Belgium, as a case study. The current extent and spatial distribution of anthropogenic urban soil (1) was estimated through reclassification of recently acquired (2012) exhaustive land cover data, discriminating three qualitative likelihood levels (high-intermediate-low) of anthropogenic influence by urbanization, and (2) compared with its occurrence as represented by the 'Technosols/Not Surveyed area' in the legacy soil map of Belgium, as this map unit best matches with the likelihood for anthropogenic urban soil at the time of the National Soil Survey conducted between end 1940s and mid 1970s. The proposed reclassification of the land cover map resulted in 16.3% and 16.7% of Flanders' total area that corresponds with a high and intermediate likelihood for anthropogenic urban soil, which highlights the underestimation of the anthropogenic urban soil extent as represented by the 'Technosol/Not Surveyed' unit in the legacy soil map (only 13.7%). Moreover, a more realistic spatial pattern of anthropogenic urban soil occurrence was obtained, providing an improved basis for urban soil spatial analysis studies. The produced anthropogenic urban soil likelihood map therefore presents a useful supporting tool for coordinating future soil surveys in urban environments.

Abstract: Enhanced pollutants removal from saline wastewater was investigated in simultaneous anammox and denitrification (SAD) process with glycine betaine (GB) addition. Long-term operation indicated the optimal GB dose was around 0.4 mM, which enhanced both anammox and denitrifying activity by 30% and 45%, respectively. The total nitrogen and organic removal rates were 0.38 +/- 0.2 kgN/m(3)/d and 0.34 +/- 0.3 kgCOD/m(3)/d, respectively, which increased by 34.5% and 20.5%. Independent of GB dose, denitrifying activity was promoted, but anammox activity was drastically deteriorated after excessive GB addition. The optimal GB dose predicated by both Gaussian and Modified-Boltzmann models were 0.42-0.45 mM. Besides, the bacterial activity recovery after excessive GB addition could be analyzed by the Modified-Boltzmann model. With 1.5 mM GB, granular floatation occurred since numerous gas bubbles were inside the granules. In general, exogenous GB addition can mitigate salinity inhibition and promote pollutants removal from saline wastewater.

Abstract: The design of eco-friendly electrocatalysts for ethanol valorization is an open challenge towards sustainable hydrogen production. Herein we present an original fabrication route to effective electrocatalysts for the ethanol oxidation reaction (EOR). In particular, hierarchical MnO(2)nanostructures are grown on high-area nickel foam scaffolds by a plasma-assisted strategy and functionalized with low amounts of optimally dispersed Au nanoparticles. This strategy leads to catalysts with a unique morphology, designed to enhance reactant-surface contacts and maximize active site utilization. The developed nanoarchitectures show superior performances for ethanol oxidation in alkaline media. We reveal that Au decoration boosts MnO(2)catalytic activity by inducing pre-dissociation and pre-oxidation of the adsorbed ethanol molecules. This evidence validates our strategy as an effective route for the development of green electrocatalysts for efficient electrical-to-chemical energy conversion.

Abstract: Using first-principles calculations, we study the effect of embedding various atoms into the nanopore sites of both C6N6 and C6N8 monolayers. Our results indicate that the embedded atoms significantly affect the electronic and magnetic properties of C6N6 and C6N8 monolayers and lead to extraordinary and multifarious electronic properties, such as metallic, half-metallic, spin-glass semiconductor and dilute-magnetic semiconductor behaviour. Our results reveal that the H atom concentration dramatically affects the C6N6 monolayer. On increasing the H coverage, the impurity states also increase due to H atoms around the Fermi-level. C6N6 shows metallic character when the H atom concentration reaches 6.25%. Moreover, the effect of charge on the electronic properties of both Cr@C6N6 and C@C6N8 is also studied. Cr@C6N6 is a ferromagnetic metal with a magnetic moment of 2.40 mu(B), and when 0.2 electrons are added and removed, it remains a ferromagnetic metal with a magnetic moment of 2.57 and 2.77 mu(B), respectively. Interestingly, one can observe a semi-metal, in which the VBM and CBM in both spin channels touch each other near the Fermi-level. C@C6N8 is a semiconductor with a nontrivial band gap. When 0.2 electrons are removed, it remains metallic, and under excess electronic charge, it exhibits half-metallic behaviour.

Abstract: First‐principles calculations, within the framework of density functional theory, are used to investigate the structural, electronic, optical, and thermoelectric properties of monolayer PbTe. The effect of layer thickness, electric field, strain, and vacancy defects on the electronic and magnetic properties is systematically studied. The results show that the bandgap decreases as the layer thickness increases from monolayer to bulk. With application of an electric field on bilayer PbTe, the bandgap decreases from 70 meV (0.2 V Å⁻¹) to 50 meV (1 V Å⁻¹) when including spin–orbit coupling (SOC). Application of uniaxial strain induces a direct‐to‐indirect bandgap transition for strain greater than +6%. In addition, the bandgap decreases under compressive biaxial strain (with SOC). The effect of vacancy defects on the electronic properties of PbTe is also investigated. Such vacancy defects turn PbTe into a ferromagnetic metal (single vacancy Pb) with a magnetic moment of 1.3 μB, and into an indirect semiconductor with bandgap of 1.2 eV (single Te vacancy) and 1.5 eV (double Pb + Te vacancy). In addition, with change of the Te vacancy concentration, a bandgap of 0.38 eV (5.55%), 0.43 eV (8.33%), and 0.46 eV (11.11%) is predicted.

Abstract: In this work, the structural, electronic and optical properties of monolayer and bilayer of boron doped C3N are investigated by means of density functional theory-based first-principles calculations. Our results show that with increasing the B dopant concentration from 3.1% to 12.5% in the hexagonal pattern, an indirect-to-direct band gap (0.8 eV) transition occurs. Furthermore, we study the effect of electric field and strain on the B doped C3N bilayer (B-C3N@2L). It is shown that by increasing E-field strength from 0.1 to 0.6V/angstrom, the band gap displays almost a linear decreasing trend, while for the > 0.6V/angstrom, we find dual narrow band gap with of 50 meV (in parallel E-field) and 0.4 eV (in antiparallel E-field). Our results reveal that in-plane and out-of-plane strains can modulate the band gap and band edge positions of the B-C3N@2L. Overall, we predict that B-C3N@2L is a new platform for the study of novel physical properties in layered two-dimensional materials (2DM) which may provide new opportunities to realize high-speed low-dissipation devices. (C) 2020 Elsevier Ltd. All rights reserved.

Abstract: In the present study ultra-fine fly ash as a novel by-product obtained by a dry and closed separation process was investigated as cement replacement in concrete. The impact of ultra-fine fly ash on material properties was investigated following an upscaling as an approach considering paste, mortar and concrete properties. Two types of cement, Portland cement (CEMI) and slag cement (CEMIII), two types of ultra-fly ashes, one with particle size d90< 9.3lm (FA1) and second with d90< 4.6lm (FA2) were used.At paste- and mortar- level, cement was replaced at 0%, 15%, 25%, 35% and 50% with FA1 and FA2. At concrete- level, cement was replaced at 0%, 15% and 25% with different ratios of FA1 and FA2. The results at paste- and mortar- level showed that an increased fineness of the fly ash (FA2) contributes to better workability of the mix. For CEMI, the compressive strength of concrete with FA2 at 25% cement replacement was already equal to the reference 0% replacement concrete at the age of 28 days. For CEMIII, the compressive strength of concrete mix with FA1 with 15% and FA2 with 25% cement replacements reached the reference concrete value at the age of 91 days. Regarding the durability, replacing cement with ultra-fine fly ash (FA2) had a positive influence on the resistivity, chloride migration coefficient and alkali-silica reaction (ASR), and a negative influence on the carbonation resistance.

Abstract: Reduced-dimensional perovskites are attractive light-emitting materials due to their efficient luminescence, color purity, tunable bandgap, and structural diversity. A major limitation in perovskite light-emitting diodes is their limited operational stability. Here we demonstrate that rapid photodegradation arises from edge-initiated photooxidation, wherein oxidative attack is powered by photogenerated and electrically-injected carriers that diffuse to the nanoplatelet edges and produce superoxide. We report an edge-stabilization strategy wherein phosphine oxides passivate unsaturated lead sites during perovskite crystallization. With this approach, we synthesize reduced-dimensional perovskites that exhibit 97 +/- 3% photoluminescence quantum yields and stabilities that exceed 300 h upon continuous illumination in an air ambient. We achieve green-emitting devices with a peak external quantum efficiency (EQE) of 14% at 1000 cd m(-2); their maximum luminance is 4.5 x 10(4) cd m(-2) (corresponding to an EQE of 5%); and, at 4000 cd m(-2), they achieve an operational half-lifetime of 3.5 h.

Abstract: The ongoing conservation treatment program of the Ghent Altarpiece by Hubert and Jan Van Eyck, one of the iconic paintings of the west, has revealed that the designs of the paintings were changed several times, first by the original artists, and then during later restorations. The central motif, The Lamb of God, representing Christ, plays an essential iconographic role, and its depiction is important. Because of the prevalence of lead white, it was not possible to visualize the Van Eycks' original underdrawing of the Lamb, their design changes, and the overpaint by later restorers with a single spectral imaging modality. However, by using elemental (x-ray fluorescence) and molecular (infrared reflectance) imaging spectroscopies, followed by analysis of the resulting data cubes, the necessary chemical contrast could be achieved. In this way, the two complementary modalities provided a more complete picture of the development and changes made to the Lamb.

Abstract: The effect of thermal cycling parameters on the phase transformation temperatures of micron and submicron grain size recrystallized Ni-Ti microwires was investigated. The suppression of martensitic transformation by thermal cycling was found to enhance when combined with room temperature aging between the cycles and enhances even more when aged at elevated temperature of 100 degrees C. While aging at room temperature alone has no clear effect on the martensitic transformation, elevated temperature aging at 100 degrees C alone suppresses the martensitic transformation. All aforementioned effects were found to be stronger in large grain samples than in small grain samples. Martensitic transformation suppression in all cases was in line with the formation of Ni4Ti3 precursors in the form of < 111 & rang;(B2) Ni clusters as concluded from the observed diffuse intensity in the electron diffraction patterns revealing short-range ordering enhancement. Performing thermal cycling in some different temperature ranges to separate the effect of martensitic transformation and high temperature range of DSC cycling revealed that both high temperature- and martensitic transformation-included cycles enhance the short-range ordering.

Abstract: A periodic spatial modulation, as created by a moire pattern, has been extensively studied with the view to engineer and tune the properties of graphene. Graphene encapsulated by hexagonal boron nitride (hBN) when slightly misaligned with the top and bottom hBN layers experiences two interfering moire patterns, resulting in a so-called supermoire (SM). This leads to a lattice and electronic spectrum reconstruction. A geometrical construction of the nonrelaxed SM patterns allows us to indicate qualitatively the induced changes in the electronic properties and to locate the SM features in the density of states and in the conductivity. To emphasize the effect of lattice relaxation, we report band gaps at all Dirac-like points in the hole doped part of the reconstructed spectrum, which are expected to be enhanced when including interaction effects. Our result is able to distinguish effects due to lattice relaxation and due to the interfering SM and provides a clear picture on the origin of recently experimentally observed effects in such trilayer heterostuctures.

Abstract: In this manuscript, we compare different analytical methodologies to validate or disprove the binding capabilities of aptamer sequences. This was prompted by the lack of a universally accepted and robust quality control protocol for the characterization of aptamer performances coupled with the observation of independent yet inconsistent data sets in the literature. As an example, we chose three aptamers with a reported affinity in the nanomolar range for ampicillin, a β-lactam antibiotic, used as biorecognition elements in several detection strategies described in the literature. Application of a well-known colorimetric assay based on aggregation of gold nanoparticles (AuNPs) yielded conflicting results with respect to the original report. Therefore, ampicillin binding was evaluated in solution using isothermal titration calorimetry (ITC), native nano-electrospray ionization mass spectrometry (native nESI-MS), and 1H-nuclear magnetic resonance spectroscopy (1H NMR). By coupling the thermodynamic data obtained with ITC with the structural information on the binding event given by native nESI-MS and 1H NMR we could verify that none of the ampicillin aptamers show any specific binding with their intended target. The effect of AuNPs on the binding event was studied by both ITC and 1H NMR, again without providing positive evidence of ampicillin binding. To validate the performance of our analytical approach, we investigated two well-characterized aptamers for cocaine/quinine (MN4), chosen for its nanomolar range affinity, and l-argininamide (1OLD) to show the versatility of our approach. The results clearly indicate the need for a multifaceted analytical approach, to unequivocally establish the actual detection potential and performance of aptamers aimed at small organic molecules.

Abstract: In solids, charge polarity can one-to-one correspond to spin polarity phenomenologically, e.g., ferroelectricity/ferromagnetism, antiferroelectricity/antiferromagnetism, and even dipole-vortex/magnetic-vortex, but ferrielectricity/ferrimagnetism kept telling a disparate story in microscopic level. Since the definition of a charge dipole involves more than one ion, there may be multiple choices for a dipole unit, which makes most ferrielectric orders equivalent to ferroelectric ones, i.e., this ferrielectricity is not necessary to be a real independent branch of polarity. In this work, by using the spherical aberration-corrected scanning transmission electron microscope, we visualize a nontrivial ferrielectric structural evolution in BaFe2Se3, in which the development of two polar sub-lattices is out-of-sync, for which we term it as irreducible ferrielectricity. Such irreducible ferrielectricity leads to a non-monotonic behavior for the temperature-dependent polarization, and even a compensation point in the ordered state. Our finding unambiguously distinguishes ferrielectrics from ferroelectrics in solids.

Abstract: The nanoscale morphology of polymer blends is a key parameter to reach high efficiency in bulk heterojunction solar cells. Thereby, research typically focusing on optimal blend morphologies while studying nonoptimized blends may give insight into blend designs that can prove more robust against morphology defects. Here, we focus on the direct correlation of morphology and device performance of thieno[3,4-b]-thiophene-alt-benzodithiophene (PTB7):[6,6]phenyl C-71 butyric acid methyl ester (PC71BM) bulk heterojunction (BHJ) blends processed without additives in different donor/acceptor weight ratios. We show that while blends of a 1:1.5 ratio are composed of large donor-enriched and fullerene domains beyond the exciton diffusion length, reducing the ratio below 1:0.5 leads to blends composed purely of polymer-enriched domains. Importantly, the photocurrent density in such blends can reach values between 45 and 60% of those reached for fully optimized blends using additives. We provide here direct visual evidence that fullerenes in the donor-enriched domains are not distributed homogeneously but fluctuate locally. To this end, we performed compositional nanoscale morphology analysis of the blend using spectroscopic imaging of low-energy-loss electrons using a transmission electron microscope. Charge transport measurement in combination with molecular dynamics simulations shows that the fullerene substructures inside the polymer phase generate efficient electron transport in the polymer-enriched phase. Furthermore, we show that the formation of densely packed regions of fullerene inside the polymer phase is driven by the PTB7:PC71BM enthalpy of mixing. The occurrence of such a nanoscale network of fullerene clusters leads to a reduction of electron trap states and thus efficient extraction of photocurrent inside the polymer domain. Suitable tuning of the polymer-acceptor interaction can thus introduce acceptor subnetworks in polymer-enriched phases, improving the tolerance for high-efficiency BHJ toward morphological defects such as donor-enriched domains exceeding the exciton diffusion length.

Abstract: Indium phosphide quantum dots (QDs) have drawn attention as alternatives to cadmium- and lead-based QDs that are currently used as phosphors in lamps and displays. The main drawbacks of InP QDs are, in general, a lower photoluminescence quantum yield (PLQY), a decreased color purity, and poor chemical stability. In this research, we attempted to increase the PLQY and stability of indium phosphide QDs by developing lattice matched InP/MgSe core-shell nanoheterostructures. The choice of MgSe comes from the fact that, in theory, it has a near-perfect lattice match with InP, provided MgSe is grown in the zinc blende crystal structure, which can be achieved by alloying with zinc. To retain lattice matching, we used Zn in both the core and shell and we fabricated InZnP/ZnxMg1-xSe core/shell QDs. To identify the most suitable conditions for the shell growth, we first developed a synthesis route to ZnxMg1-xSe nanocrystals (NCs) wherein Mg is effectively incorporated. Our optimized procedure was employed for the successful growth of ZnxMg1-xSe shells around In(Zn)P QDs. The corresponding core/ shell systems exhibit PLQYs higher than those of the starting In(Zn)P QDs and, more importantly, a higher color purity upon increasing the Mg content. The results are discussed in the context of a reduced density of interface states upon using better lattice matched ZnxMg1-xSe shells.