Abstract: Mainstream nitrogen removal by partial nitritation/anammox (PN/A) can realize energy and cost savings for sewage treatment. Selective suppression of nitrite oxidizing bacteria (NOB) remains a key bottleneck for PN/A implementation. A rotating biological contactor was studied with an overhead cover and controlled air/N2 inflow to regulate oxygen availability at 20 °C. Biofilm exposure to dissolved oxygen concentrations < 0.51 ± 0.04 mg O2 L-1 when submerged in the water and < 1.41 ± 0.31 mg O2 L-1 when emerged in the headspace (estimated), resulted in complete and long-term NOB suppression with a low relative nitrate production ratio of 10 ± 4%. Additionally, weekly biofilm stressor treatments with free ammonia (FA) (29 ± 1 mg NH3-N L-1 for 3 h) could improve the NOB suppression while free nitrous acid treatments had insufficient effect. This study demonstrated the potential of managing NOB suppression in biofilm-based systems by oxygen control and recurrent FA exposure, opening opportunities for resource efficient nitrogen removal.

Abstract: A technical examination of the Last Judgment triptych by Hieronymus Bosch in the Paintings Gallery of the Academy of Fine Arts, Vienna, has revealed a painted escutcheon with the coat of arms of the Burgundian court official Hippolyte de Berthoz underneath the current surface of the right outer wing. This allows him to be firmly identified as the painting's patron.

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: In recent decades, as crop production has increased in many areas where irrigation projects have been implemented, the global agricultural development community has promoted irrigation investments. However, due to the disappointing performance of irrigation farming in developing countries, irrigation intervention in Africa South of the Sahara including Ethiopia is an issue of debate. Moreover, several gaps exist in the Ethiopian irrigation farming literature. For instance, evidence about the direct and indirect effects of irrigation water on agriculture is not well documented. The irrigation farming literature has not disentangled the indirect effects of having access to irrigation water from the direct effect and the indirect effects have been underrepresented. Furthermore, most previous studies have applied either a quantitative or qualitative approach and have relied only on revealed data as main type of methodology, making studies that combine qualitative and quantitative research and that use both stated and revealed data underrepresented. In this study, different approaches have been applied to investigate how irrigation water impacts Ethiopia agriculture with special attention being given to disentangling the direct and indirect effects of irrigation water on Ethiopian agriculture. Using a structural equation model, a stochastic production frontier approach, and a discrete choice experiment, I drew evidence regarding the direct and indirect effects of irrigation water on crop revenue of smallholder farmers, the technical efficiency of irrigation user farmers, and the farmers’ willingness to pay to improve poor irrigation schemes from field observations, semi-structured interviews and focus group discussions with farmers, and key informant interviews with the local agricultural agents from the Koga and Fogera Districts of Amhara Region Ethiopia. The results indicate that irrigation water in general has both direct and indirect positive effects on agriculture, and the indirect effect is mediated by both improved farm inputs and the type of crops produced. The results also show that – due to poor extension services and backward agronomic practices, the mean technical efficiency of farmers in Ethiopia is very low, and that large-scale irrigation users are less technically efficient than small-scale irrigation users. Moreover, the results show that improving irrigation schemes shifts the frontier up, and smallholder farmers are strongly willing to contribute financially to the maintenance costs of irrigation schemes. The results offer relevant lessons for policymakers that providing irrigation water supply must be embedded in a comprehensive support package including access to extension services, improved input supply, and access to stable markets.

Abstract: Increasing efforts are directed towards the development of sustainable alternative protein sources among which microbial protein (MP) is one of the most promising. Especially when waste streams are used as substrates, the case for MP could become environmentally favorable. The risks of using organic waste streams for MP production–the presence of pathogens or toxicants–can be mitigated by their anaerobic digestion and subsequent aerobic assimilation of the (filter-sterilized) biogas. Even though methane and hydrogen oxidizing bacteria (MOB and HOB) have been intensively studied for MP production, the potential benefits of their co-cultivation remain elusive. Here, we isolated a diverse group of novel HOB (that were capable of autotrophic metabolism), and co-cultured them with a defined set of MOB, which could be grown on a mixture of biogas and H2/O2. The combination of MOB and HOB, apart from the CH4 and CO2 contained in biogas, can also enable the valorization of the CO2 that results from the oxidation of methane by the MOB. Different MOB and HOB combinations were grown in serum vials to identify the best-performing ones. We observed synergistic effects on growth for several combinations, and in all combinations a co-culture consisting out of both HOB and MOB could be maintained during five days of cultivation. Relative to the axenic growth, five out of the ten co-cultures exhibited 1.1–3.8 times higher protein concentration and two combinations presented 2.4–6.1 times higher essential amino acid content. The MP produced in this study generally contained lower amounts of the essential amino acids histidine, lysine and threonine, compared to tofu and fishmeal. The most promising combination in terms of protein concentration and essential amino acid profile was Methyloparacoccus murrelli LMG 27482 with Cupriavidus necator LMG 1201. Microbial protein from M. murrelli and C. necator requires 27–67% less quantity than chicken, whole egg and tofu, while it only requires 15% more quantity than the amino acid-dense soybean to cover the needs of an average adult. In conclusion, while limitations still exist, the co-cultivation of MOB and HOB creates an alternative route for MP production leveraging safe and sustainably-produced gaseous substrates.

Abstract: Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.

Abstract: Lignosulfonate-based bioactive coatings as soil improvers for lawns were developed using laccase as a biocatalyst. Incorporation of glycerol, xylitol and sorbitol as plasticizers considerably reduced the brittleness of the synthesized coatings of marine carbonate granules while thermal enzyme inactivation at 100 degrees C enabled the production of stable coatings. Heat inactivation produced stable coatings with a molecular weight of 2000 kDa and a viscosity of 4.5 x 10(-3) Pas. The desired plasticity for the spray coating of soil improver granules was achieved by the addition of 2.7% of xylitol. Agriculture beneficial microorganisms (four different Bacillus species) were integrated into the coatings. The stable coatings protected the marine calcium carbonate granules, maintained the viability of the microorganisms and showed no toxic effects on the germination and growth of model plants including corn, wheat, salad, and tomato despite a slight delay in germination. Moreover, the coatings reduced the dust formation of soil improvers by 70%. CO2 emission analysis showed potential for the reduction of up to 3.4 kg CO2-eq. kg(-1) product, making it a viable alternative to fossil-based coatings.

Abstract: Resource recovery and reuse from domestic wastewater has become an important subject for the current development of sanitation technologies and infrastructures. Different technologies are available and combined into sanitation concepts, with different performances. This study provides a methodological approach to evaluate the sustainability of these sanitation concepts with focus on resource recovery and reuse. St. Eustatius, a small tropical island in the Caribbean, was used as a case study for the evaluation. Three source separation-communityon-site and two combined sewerage island-scale concepts were selected and compared in terms of environmental (net energy use, nutrient recovery/reuse, BOD/COD, pathogens, and GHG emission, land use), economic (CAPEX and OPEX), social cultural (acceptance, required competences and education), and technological (flexibility/ adaptability, reliability/continuity of service) indicators. The best performing concept, is the application of Upflow Anaerobic Sludge Bed (UASB) and Trickling Filter (TF) at island level for combined domestic wastewater treatment with subsequent reuse in agriculture. Its overall average normalised score across the four categories (i. e., average of average per category) is about 15% (0.85) higher than the values of the remaining systems and with a score of 0.73 (conventional activated sludge – centralised level), 0.77 (UASB-septic tank (ST)), 0.76 (UASB-TF – community level), and 0.75 (ST – household level). The higher score of the UASB-TF at community level is mainly due to much better performance in the environmental and economic categories. In conclusion, the case study provides a methodological approach that can support urban planning and decision-making in selecting more sustainable sanitation concepts, allowing resource recovery and reuse in small island context or in other contexts.

Abstract: The adsorption of various environmental gas molecules, including H-2, N-2, CO, CO2, O-2, NO, NO2, SO2 H2O, H2S, NH3 and CH4, on the surface of the recently synthesized two dimensional MoSi2N4 (MSN) monolayer has been investigated by means of spin-polarized first-principles calculations. The most stable adsorption configuration, adsorption energy, and charge transfer have been computed. Due to the weak interaction between molecules studied with the MSN monolayer surface, the adsorption energy is small and does not yield any significant distortion of the MSN lattice, i.e., the interaction between the molecules and MSN monolayer surface is physisorption. We find that all molecules are physisorbed on the MSM surface with small charge transfer, acting as either charge acceptors or donors. The MSN monolayer is a semiconductor with an indirect band gap of 1.79 eV. Our theoretical estimations reveal that upon adsorption of H-2, N-2, CO, CO2, NO, H2O, H2S, NH3 and CH4 molecules, the semiconducting character of MSN monolayer is preserved and the band gap value is decreased to similar to 1.5 eV. However, the electronic properties of the MSN monolayer can be significantly altered by adsorption of O-2, NO and SO2, and a spin polarization with magnetic moments of 2, 1, 2 mu(B), respectively, can be introduced. Furthermore, we demonstrate that the band gap and the magnetic moment of adsorbed MSN monolayer can be significantly modulated by the concentration of NO and SO2 molecules. As the concentration of NO2 molecule increases, the magnetic moment increase from 1 mu(B) to 2 and 3 mu(B). In the case of the SO2 molecule with increasing of concentration, the band gap decreases from 1.2 eV to 1.1 and 0.9 eV. Obviously, our theoretical studies indicate that MSN monolayer-based sensor has a high application potential for O-2, NO, NO2 and SO2 detection.

Abstract: Using first-principles many-body perturbation theory, we investigate the optical properties of 8-Pmmn borophene at two levels of approximations; the GW method considering only the electron-electron interaction and the GW in combination with the Bethe-Salpeter equation including electron-hole coupling. The band structure exhibits anisotropic Dirac cones with semimetallic character. The optical absorption spectra are obtained for different light polarizations and we predict strong optical absorbance anisotropy. The absorption peaks undergo a global redshift when the electron-hole interaction is taken into account due to the formation of bound excitons which have an anisotropic excitonic wave function.

Abstract: Optical-photothermal infrared (O-PTIR) spectroscopy is a recently developed technique that provides spectra comparable to traditional transmission FTIR spectroscopy with nanometric spatial resolution. Hence, O-PTIR is a promising candidate for the analysis of historical paintings, as well as other cultural heritage objects, but its potential has not yet been evaluated.

Abstract: Direct experimental measurement of thermal expansion coefficient without substrate effects is a challenging task for two-dimensional (2D) materials, and its accurate estimation with large-scale ab initio molecular dynamics is computationally very expensive. Machine learning-based interatomic potentials trained with ab initio data have been successfully used in molecular dynamics simulations to decrease the computational cost without compromising the accuracy. In this study, we investigated using Gaussian approximation potentials to reproduce the density functional theory-level accuracy for graphene within both lattice dynamical and molecular dynamical methods, and to extend their applicability to larger length and time scales. Two such potentials are considered, GAP17 and GAP20. GAP17, which was trained with pristine graphene structures, is found to give closer results to density functional theory calculations at different scales. Further vibrational and structural analyses verify that the same conclusions can be deduced with density functional theory level in terms of the reasoning of the thermal expansion behavior, and the negative thermal expansion behavior is associated with long-range out-of-plane phonon vibrations. Thus, it is argued that the enabled larger system sizes by machine learning potentials may even enhance the accuracy compared to small-size-limited ab initio molecular dynamics.

Abstract: Inspired by the recent successful growth of Ti2C and Ti3C2 monolayers, here, we investigate the structural, electronic, and mechanical properties of functionalized Ti2C and Ti3C2 monolayers by means of density functional theory calculations. The results reveal that monolayers of Ti2C and Ti3C2 are dynamically stable metals. Phonon band dispersion calculations demonstrate that two-surface functionalization of Ti2C and Ti(3)C(2)via chalcogenides (S, Se, and Te), halides (F, Cl, Br, and I), and oxygen atoms results in dynamically stable novel functionalized monolayer materials. Electronic band dispersions and density of states calculations reveal that all functionalized monolayer structures preserve the metallic nature of both Ti2C and Ti3C2 except Ti2C-O-2, which possesses the behavior of an indirect semiconductor via full-surface oxygen passivation. In addition, it is shown that although halide passivated Ti3C2 structures are still metallic, there exist multiple Dirac-like cones around the Fermi energy level, which indicates that semi-metallic behavior can be obtained upon external effects by tuning the energy of the Dirac cones. In addition, the computed linear-elastic parameters prove that functionalization is a powerful tool in tuning the mechanical properties of stiff monolayers of bare Ti2C and Ti3C2. Our study discloses that the electronic and structural properties of Ti2C and Ti3C2 MXene monolayers are suitable for surface modification, which is highly desirable for material property engineering and device integration.

Abstract: The European automotive sector is faced with potentially disruptive challenges. In particular, the projected increase in the share of electric vehicles (EVs) and calls to prepare for the implementation of more circular economy (CE) strategies are increasingly demanding systemic adaptations. Given the goals of the CE, the adaptations should enable a maximal preservation of the function and value of products (e.g. extension of lifetime), components (e.g. reuse of parts) and materials (e.g., material recycling), thus saving on the energy, materials and effort that would be required to restore the lost functionalities. In this context, statistical entropy analysis (SEA) is proposed as a methodology to assess the effort needed for preserving and restoring functionality at different product, component and material life cycle stages. Effort is measured as changes in statistical entropy that are caused by concentration and dilution activities in the production – consumption – End-of-Life (EoL) system. SEA was applied to a generic model of the European automotive system, in combination with a stock-driven model and a material flow analysis (MFA), allowing statistical entropy changes to be projected over time. The paper demonstrates how SEA can facilitate decision making on the transition towards a more circular economy by quantifying the effects of particular CE strategies and their combinations. The results show that without any additional system adaptations, an increasing share of EVs towards the year 2050 will lead to substantially increased effort in production as well as end-of-life vehicle treatment.

Abstract: Excitonic properties of Ge2H2 and Sn2H2, also known as Xanes, are investigated within the effective mass model. A perpendicularly applied magnetic field induces a negative shift on the exciton center-of-mass kinetic energy that is approximately quadratic with its momentum, thus pushing down the exciton dispersion curve and flattening it. This can be interpreted as an increase in the effective mass of the magneto-exciton, tunable by the field intensity. Our results show that in low effective mass two-dimensional semiconductors, such as Xanes, the applied magnetic field allows one to tune the magneto-exciton effective mass over a wide range of values.