Abstract: Polycrystalline samples of CaLa2FeCoSbO9 and ALa2FeNiSbO9 (A=Ca, Sr, Ba) have been prepared in solid-state reactions and studied by a combination of transmission electron microscopy, magnetometry, X-ray diffraction, neutron diffraction and Mössbauer spectroscopy. Diffraction and TEM showed that each shows 1:1 B-site ordering in which Co2+/Ni2+ and Sb5+ tend to occupy two distinct crystallographic sites while Fe3+ is distributed over both sites. While X-ray and neutron diffraction agreed that all four compositions are monophasic with space group P21/n, TEM revealed different levels of compositional inhomogeneity at the subcrystal scale, which, in the case of BaLa2FeNiSbO9, leads to the occurrence of both a P21/n and an I2/m phase. Magnetometry and neutron diffraction show that these perovskites are ferrimagnets with a G-type magnetic structure. Their relatively low magnetisation can be attributed to their inhomogeneity. This work demonstrates the importance of studying the microstructure of complex compositions.

Abstract: When ceria is used as a support for many redox catalysis involved in green catalysis, it is well-known that the overlying noble metal can gain access to a significant quantity of oxygen atoms with high mobility and fast reduction and oxidation properties under mild conditions. However, it is as yet unclear what the underlying principle and the nature of the ceria surface involved are. By using two tailored morphologies of ceria nanocrystals, namely cubes and rods, it is demonstrated from Scanning Transmission Electron Microscopy with Electron Energy Loss Spectroscopy (STEM-EELS) mapping and Pulse Isotopic Exchange (PIE) that ceria nano-cubes terminated with a polar surface (100) can give access to more than the top most layer of surface oxygen atoms. Also, they give higher oxygen mobility than ceria nanorods with a non-polar facet of (110). A new insight for the possible additional role of polar ceria surface plays in the oxygen mobility is obtained from Density Functional Theory (DFT) calculations which suggest that the (100) surface sites that has more than half-filled O on same plane can drive oxygen atoms to oxidise adsorbate(s) on Pd due to the strong electrostatic repulsion.

Abstract: As a response to increasing urbanization and changing weather and climatic patterns, urban green infrastructure (UGI) emerged as a concept to increase resilience within the urban boundaries. Given that implementing these (semi-) natural solutions in practice requires a clear overview of the costs and benefits, valuation becomes ever important. A range of decision-support tools for green infrastructure and ecosystem services exist, developed for various purposes. This paper reviews the potential of 10 shortlisted and existing valuation tools to support investment decisions of urban green infrastructure. In the assessment, the functionality is regarded specifically from the urban planning and decision-making viewpoint. The toolkits were evaluated on 12 different criteria. After analyzing the toolkits on these criteria, the findings are evaluated on the (mis)match with specific requirements in the urban planning and management context. Secondly, recommendations and guidelines are formulated to support the design of simple valuation tools, tailored to support the development of green infrastructure in urban areas. Approaching the valuation toolkits biophysically and (socio-)economically provides an integral overview of the challenges and opportunities of the capacities of each framework. It was found that most tools are not designed for the peculiarities of the urban context. Several elements contribute to the hampering uptake of GI valuation tools. Firstly, the limited effort in the economic case for green infrastructure remains a burden to use toolkits to compare grey and green alternatives. Secondly, tools are currently seldom designed for the peculiarities of cities: urban ecosystem (dis)services, multi-scalability, life-span assessments of co-benefits and the importance of social benefits. Thirdly, toolkits should be the result of co-development between the scientific community and local authorities in order to create toolkits that are tailor made to the specific needs in the urban planning process. It can be concluded that current tools, are not readily applicable to support decision making as such. However, if applied cautiously, they can have an indicative role to pinpoint further targeted and in-depth analyses.

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: We present the Tight-Binding Studio (TB Studio) software package that calculates the different parameters of a tight-binding Hamiltonian from a set of Bloch energy bands obtained from first principle theories such as density functional theory, Hartree-Fock calculations or semi-empirical band-structure theory. This will be helpful for scientists who are interested in studying electronic and optical properties of structures using Green's function theory within the tight-binding approximation. TB Studio is a cross-platform application written in C++ with a graphical user interface design that is user-friendly and easy to work with. This software is powered by Linear Algebra Package C interface library for solving the eigenvalue problems and the standard high performance OpenGL graphic library for real time plotting. TB Studio and its examples together with the tutorials are available for download from tight-binding.com. Program summary Program Title: Tight-Binding Studio Program Files doi:http://dx.doi.org/10.17632/j6x5mwzm2d.1 Licensing provisions: LGPL Programming language: C++ External routines: BLAS, LAPACK, LAPACKE, wxWidgets, OpenGL, MathGL Nature of problem: Obtaining Tight-Binding Hamiltonian from a set of Bloch energy bands obtained from first-principles calculations. Solution method: Starting from the simplified LCAO method, a tight-binding model in the two-center approximation is constructed. The Slater and Koster (SK) approach is used to calculate the parameters of the TB Hamiltonian. By using non-linear fitting approaches the optimal values of the SK parameters are obtained such that the TB energy eigenvalues are as close as possible to those from first-principles calculations. We obtain the expression for the Hamiltonian and the overlap matrix elements between the different orbitals of the different atoms in an orthogonal or non-orthogonal basis set. (C) 2020 Elsevier B.V. All rights reserved.

Abstract: The relationship between irrigation water availability and crop revenue is multifaceted. However, most of the previous studies focused only on the direct effect of irrigation water on crop revenue or considered that the indirect effect passes only through the farmers’ improved farm inputs usage. Nevertheless, unlike previous studies, this study argues that a one-sided argument that irrigation water directly causes high crop revenue or indirectly affects crop revenue only via the farmers’ improved farm inputs usage is incomplete, as irrigation water not only directly contributes to crop revenue but also indirectly conduces to crop revenue via both the type of crops produced and the farmers’ improved farm inputs usage. Considering the previous studies’ limitations, this study investigates pathways how small-scale irrigation water affects crop revenue and identifies challenges of small-scale irrigation farming in Fogera district, Ethiopia. Results endorsed that irrigation water has both direct and indirect effects on crop revenue. The indirect effect is 67 percent of the total effect and it is mediated by both the type of crops produced and farmers’ improved farm inputs usage. The result also indicated that irrigation user farmers have a higher income, more livestock assets and resources and better food, housing, and cloths than the non-users. Moreover, challenges related to agricultural output and input market were identified as the most severe problem followed by crop disease. The findings of our study suggest that to utilize the benefits of irrigation water properly, it is crucial to encourage farmers to use more improved farm inputs and to shift from staple to cash crop production. Moreover, farmers are frequently exposed to cheating by illegal brokers in the output market, therefore it is also important to increase farmers’ accessibility to output and input markets, the quality of improved farm inputs, and the bargaining power of farmers with market information.

Abstract: In electron microscopy, the maximum a posteriori (MAP) probability rule has been introduced as a tool to determine the most probable atomic structure from high-resolution annular dark-field (ADF) scanning transmission electron microscopy (STEM) images exhibiting low contrast-to-noise ratio (CNR). Besides ADF imaging, STEM can also be applied in the annular bright-field (ABF) regime. The ABF STEM mode allows to directly visualize light-element atomic columns in the presence of heavy columns. Typically, light-element nanomaterials are sensitive to the electron beam, limiting the incoming electron dose in order to avoid beam damage and leading to images exhibiting low CNR. Therefore, it is of interest to apply the MAP probability rule not only to ADF STEM images, but to ABF STEM images as well. In this work, the methodology of the MAP rule, which combines statistical parameter estimation theory and model-order selection, is extended to be applied to simultaneously acquired ABF and ADF STEM images. For this, an extension of the commonly used parametric models in STEM is proposed. Hereby, the effect of specimen tilt has been taken into account, since small tilts from the crystal zone axis affect, especially, ABF STEM intensities. Using simulations as well as experimental data, it is shown that the proposed methodology can be successfully used to detect light elements in the presence of heavy elements.

Abstract: We present a quantitative method which allows us to reliably measure dynamic changes in the atomic structure of monatomic crystalline nanomaterials from a time series of atomic resolution annular dark field scanning transmission electron microscopy images. The approach is based on the so-called hidden Markov model and estimates the number of atoms in each atomic column of the nanomaterial in each frame of the time series. We discuss the origin of the improved performance for time series atom-counting as compared to the current state-of-the-art atom-counting procedures, and show that the so-called transition probabilities that describe the probability for an atomic column to lose or gain one or more atoms from frame to frame are particularly important. Using these transition probabilities, we show that the method can also be used to estimate the probability and cross section related to structural changes. Furthermore, we explore the possibilities for applying the method to time series recorded under variable environmental conditions. The method is shown to be promising for a reliable quantitative analysis of dynamic processes such as surface diffusion, adatom dynamics, beam effects, or in situ experiments.

Abstract: In this study we performed microscopic characterization of mineral particles that were collected in the thorium-rich Fen Complex in Norway and identified and isolated based on autoradiography in function of their radioactivity. For this we combined information obtained with X-ray absorption mu-CT, mu-XRF and mu-XRD, both in bi- and in three-dimensional (tomographic) mode. We demonstrate that radionuclides and metals are heterogeneously distributed both within soil samples and within individual Th-enriched aggregates, which are characterised as low-density mineral bulk particles with high density material inclusions, where Th as well as several metals are highly concentrated. For these sites, it is important to take into account how these inhomogeneous distributions could affect the overall environmental behaviour of Th and progeny upon weathering due to human or environmental factors. Moreover, the estimated size of the Th-containing inclusions as determined in this work represents information of importance for the characterization of radionuclides and toxic metals exposure, as well as for assessing the viability of mining for Th and rare-earth metals in the Fen Complex and the associated environmental impact.

Abstract: The present study describes a multivariate strategy that can be used for automatic on-site processing of reflection mode macro FTIR mapping (MA-rFTIR) data obtained during investigation of artworks. The chemometric strategy is based on the integration of principal component analysis (PCA) with a clustering approach in the space subtended by the three lowest-order principal components and allows to automatically identify the regions of interest (ROIs) of the area scanned and to extract the average FTIR spectra related to each ROI. Thanks to the automatic data management, in-field HSI (hyperspectral imaging)-based analyses may be performed even by staff lacking specific advanced chemometric expertise, as it is sometimes the case for conservation scientists or conservators with a scientific background. MA-rFTIR was only recently introduced in the conservation field and, in this work the technique was employed to characterize the surface of metallic artefacts. The analytical protocol was employed as part of a rapid procedure to evaluate the conservation state and the performance of cleaning methods on bronze objects. Both activities are commonly part of restoration campaigns of bronzes and require an on-site analytical procedure for efficient and effective diagnosis. The performance of the method was first evaluated on aged standard samples (bronzes with a layer of green basic copper hydroxysulphate, treated with different organic coatings) and then scrutinized in situ on areas of the 16th century Neptune fountain statue (Piazza del Nettuno, Bologna, Italy) by Gianbologna.

Abstract: This work encompasses an in-depth transmission electron microscopy and atom probe tomography study of Ti-stabilized austenitic steel irradiated with Fe-ions. The focus is on radiation induced segregation and precipitation, and in particular on how Ti and TiC affect these processes. A 15-15Ti steel (grade: DIN 1.4970) in two thermo-mechanical states (cold-worked and aged) was irradiated at different temperatures up to a dose of 40 dpa. At low irradiation temperatures, the cold-worked and aged materials evolved to a similar microstructure dominated by small Si and Ni clusters, corresponding to segregation to small point defect clusters. TiC precipitates, initially present in the aged material, were found to be unstable under these irradiation conditions. Elevated irradiation temperatures resulted in the nucleation of nanometer sized Cr enriched TiC precipitates surrounded by Si and Ni enriched shells. In addition, nanometer sized Ti- and Mn-enriched G-phase (M6Ni16Si7) precipitates formed, often attached to TiC precipitates. Post irradiation, larger number densities of TiC were observed in the cold-worked material compared to the aged material. This was correlated with a lower volume fraction of G-phase. The findings suggest that at elevated irradiation temperatures, the precipitate-matrix interface is an important point defect sink and contributes to the improved radiation resistance of this material. The study is a first of its kind on stabilized steel and demonstrates the significance of the small Ti addition to the evolution of the microstructure under irradiation. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Abstract: Resource recovery from source-separated urine can shorten nutrient cycles on Earth and is essential in regenerative life support systems for deep-space exploration. In this study, a robust two-stage, energy-efficient, gravity-independent urine treatment system was developed to transform fresh real human urine into a stable nutrient solution. In the first stage, up to 85% of the COD was removed in a microbial electrolysis cell (MEC), converting part of the energy in organic compounds (27-46%) into hydrogen gas and enabling full nitrogen recovery by preventing nitrogen losses through denitrification in the second stage. Besides COD removal, all urea was hydrolysed in the MEC, resulting in a stream rich in ammoniacal nitrogen and alkalinity, and low in COD. This stream was fed into a membrane-aerated biofilm reactor (MABR) in order to convert the volatile and toxic ammoniacal nitrogen to non-volatile nitrate by nitrification. Bio-electrochemical pre-treatment allowed to recover all nitrogen as nitrate in the MABR at a bulk-phase dissolved oxygen level below 0.1 mg O2 L-1. In contrast, feeding the MABR directly with raw urine (omitting the first stage), at the same nitrogen loading rate, resulted in nitrogen loss (18%) due to denitrification. The MEC and MABR were characterised by very distinct and diverse microbial communities. While (strictly) anaerobic genera, such as Geobacter (electroactive bacteria), Thiopseudomonas, a Lentimicrobiaceae member, Alcaligenes and Proteiniphilum prevailed in the MEC, the MABR was dominated by aerobic genera, including Nitrosomonas (a known ammonium oxidiser), Moheibacter and Gordonia. The two-stage approach yielded a stable nitrate-rich, COD-low nutrient solution, suitable for plant and microalgae cultivation.

Abstract: The limitation in time and length scale is a major issue of molecular dynamics (MD) simulation. Although several methods have been developed to extend the MD time scale, their performance usually deteriorates with increasing system size. Therefore, an acceleration method which is applicable to large systems is required to bridge the gap between the MD simulations and target phenomena. In this study, an accelerated MD method for large system is developed based on the collective variable-driven hyperdynamics (CVHD) method [K.M. Bal and E.C. Neyts, 2015]. The key idea is to run CVHD in parallel with rate control and accelerate multiple possible events simultaneously. Using this novel method, carbon diffusion in bcc-iron bicrystal with grain boundary is examined as an application for practical materials. Carbon atoms reaching at the grain boundary are trapped whereas carbon atoms in the bulk region diffuse randomly, and both dynamic regimes can be simultaneously accelerated with the parallel CVHD technique.

Abstract: Anammox, the oxidation of ammonium with nitrite, is a key microbial process in the nitrogen cycle. Under mesophilic conditions (below 40 °C), it is widely implemented to remove nitrogen from wastewaters lacking organic carbon. Despite evidence of the presence of anammox bacteria in high-temperature environments, reports on the cultivation of thermophilic anammox bacteria are limited to a short-term experiment of 2 weeks. This study showcases the adaptation of a mesophilic inoculum to thermophilic conditions, and its characterization. First, an attached growth technology was chosen to obtain the process. In an anoxic fixed-bed biofilm bioreactor (FBBR), a slow linear temperature increase from 38 to over 48 °C (0.05–0.07 °C d−1) was imposed to the community over 220 days, after which the reactor was operated at 48 °C for over 200 days. Maximum total nitrogen removal rates reached up to 0.62 g N L−1 d−1. Given this promising performance, a suspended growth system was tested. The obtained enrichment culture served as inoculum for membrane bioreactors (MBR) operated at 50 °C, reaching a maximum total nitrogen removal rate of 1.7 g N L−1 d−1 after 35 days. The biomass in the MBR had a maximum specific anammox activity of 1.1 ± 0.1 g NH4+-N g−1 VSS d−1, and the growth rate was estimated at 0.075–0.19 d−1. The thermophilic cultures displayed nitrogen stoichiometry ratios typical for mesophilic anammox: 0.93–1.42 g NO2--Nremoved g−1 NH4+-Nremoved and 0.16–0.35 g NO3--Nproduced g−1 NH4+-Nremoved. Amplicon and Sanger sequencing of the 16S rRNA genes revealed a disappearance of the original “Ca. Brocadia” and “Ca. Jettenia” taxa, yielding Planctomycetes members with only 94–95% similarity to “Ca. Brocadia anammoxidans” and “Ca. B. caroliniensis”, accounting for 45% of the bacterial FBBR community. The long-term operation of thermophilic anammox reactors and snapshot views on the nitrogen stoichiometry, kinetics and microbial community open up the development path of thermophilic partial nitritation/anammox. A first economic assessment highlighted that treatment of sludge reject water from thermophilic anaerobic digestion of sewage sludge may become attractive.