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In this work, a DDPM-CFD model is developed in ANSYS® Fluent for the simulation of the indirectly heated, bubbling calciner of the 300kWth dual fluidized bed pilot plant located at Technische Universität Darmstadt. The calciner is heated by 72 heat pipes that carry the heat from an external combustor. Regarding the heat transfer, both convection and radiation are considered in the model. Regarding the modelling of the drag forces, flow heterogeneity aspects are considered by applying the Energy Minimization Multi-Scale (EMMS) scheme. However, the application of DDPM in such dense, bubbling flows considered here proved to be challenging, demanding several advancements and customizations. To this end, this study proposes mainly three advancements; i) The inter-particle forces are modelled using custom user defined functions incorporating both normal and tangential components. In particular, KTGF-based correlations are applied at dilute regions, while at dense regions the solid pressure is modelled according to Harris and Crighton, and the shear and bulk viscosities are modelled using correlations based on the plastic theory. ii) It is shown that, in order to correctly predict the overall pressure drop, the Lagrangian particle momentum equation should be reformulated according to Model A formulation to be consistent with the solved gas-phase momentum equation. iii) In order to capture the correct heat flux levels, the heat flux on the heat pipe heat exchanger walls is modelled in the Eulerian reference frame scaling the temperature gradient on the wall to take into account the thin thermal boundary layer. Τhe DDPM results are compared against those of an already validated Eulerian TFM model, in terms of calculated flow patterns, volume fractions, pressure profiles and heat fluxes. In addition, both models are assessed for their computational cost. The developed DDPM model predicts practically the same overall pressure drop with the TFM model. However, it overpredicts the bed length by 12% when using the default grid. This reduces to 6% when using a finer grid comprising double computational cells. As for the heat fluxes and the calcination reaction rate, both models predict similar levels and their differences are attributed to the differences in hydrodynamics. Peer reviewed

New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is, therefore, of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, that is whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterized the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence, and genetic background. We find statistical support for the presence of variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and those evolutionarily recent events, such as demographic changes and local adaptation, have little impact. Nasl. z nasl. zaslona. Opis vira z dne 12. 12. 2023. Število sodelavcev v konzorciju GenTree Consortium: 128. Sodelavca pri raziskavi: M. Bajc. M. Westergen. Bibliografija: str. 15-16. Abstract.

This work is supported by the National Natural Science Foundation of China (NSFC) project (92044301, 42220104006, 42075101 and 41975154), the Academy of Finland (1251427, 1139656, 296628, 306853, 316114 and 311932), the Finnish Centre of Excellence (1141135 and 307331), the European Union’s Horizon 2020 programme (ERC, project no.742206 ‘ATM-GTP’, no. 850614 ‘CHAPAs’ and no. 895875 ‘NPF-PANDA’), the trans-national ERA-PLANET project SMURBS (project no. 689443) under the EU Horizon 2020 Framework Programme, the European Regional Development Fund, the Urban Innovative Actions initiative (HOPE; Healthy Outdoor Premises for Everyone, project no. UIA03 − 240), MegaSense by Business Finland (grant no. 7517/31/2018) and Academy of Finland Flagship funding (grant no. 337549). The Beijing University of Chemical Technology team is supported by the National Natural Science Foundation of China (42275117) and the Beijing Natural Science Foundation (8232041). Y.J.T. acknowledges the funding support from the National Natural Science Foundation of China (42175118) and the Guangdong Basic and Applied Basic Research Foundation (2022A1515010852). The CSIC team acknowledges the funding support from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation Programme (project ERC‐2016‐COG, project no. 726349 CLIMAHAL to A.S.-L.). The Tsinghua University team acknowledges the National Natural Science Foundation of China (22188102) and Samsung PM2.5 SRP. N.M.D. acknowledges the US National Science Foundation grant AGS2132089. H.W. acknowledges the funding support from the National Natural Science Foundation of China (42175111). The Indian Institute of Tropical Meteorology is funded by the Ministry of Earth Sciences, Government of India. We acknowledge the German federal environmental agency for kindly providing us with the O3, NOx and PM2.5 and PM10 data in Frankfurt and Berlin. The data at the Frankfurt sites were measured by Hessisches Landesamt für Naturschutz, Umwelt und Geologie and the data at the Berlin sites were measured by Senatsverwaltung für Umwelt, Mobilität, Verbraucher- und Klimaschutz. We thank them for their great efort. We acknowledge the Madrid Air Quality Monitoring Network, Smart SMEAR Network, India Central Pollution Control Board and California Air Resources Board for the NOx, O3, CO and PM2.5 open data sources. Nitrate comprises the largest fraction of fine particulate matter in China during severe haze. Consequently, strict control of nitrogen oxides (NOx) emissions has been regarded as an effective measure to combat air pollution. However, this notion is challenged by the persistent severe haze pollution observed during the COVID-19 lockdown when NOx levels substantially declined. Here we present direct field evidence that diminished nitrogen monoxide (NO) during the lockdown activated nocturnal nitrogen chemistry, driving severe haze formation. First, dinitrogen pentoxide (N2O5) heterogeneous reactions dominate particulate nitrate (pNO3−) formation during severe pollution, explaining the higher-than-normal pNO3− fraction in fine particulate matter despite the substantial NOx reduction. Second, N2O5 heterogeneous reactions provide a large source of chlorine radicals on the following day, contributing drastically to the oxidation of volatile organic compounds, and thus the formation of oxygenated organic molecules and secondary organic aerosol. Our findings highlight the increasing importance of such nocturnal nitrogen chemistry in haze formation caused by NOx reduction, motivating refinements to future air pollution control strategies. Peer reviewed

This study focuses for the first time on the transient three-dimensional CFD simulation of the novel bubbling-bed calciner of an indirectly heated calcium looping pilot plant. The granular flow in the calciner is modelled according to the state-of-the-art Eulerian–Eulerian (Two Fluid Model — TFM) approach. To take into account flow heterogeneity aspects, the drag coefficient is modelled applying the sub-grid energy-minimization multiscale (EMMS) scheme, customized for the specific operating conditions. For the calcination kinetics a changing grain size model (CGSM) from Labiano et al. is used. An important advancement of the current approach lies on the consideration of all the related heat transfer mechanisms from the heat pipes towards the bubbling bed, i.e., both convection and radiation are considered. The simulation results are verified against data measurements obtained from an experimental campaign performed at Technische Universität Darmstadt. The CFD model provides an accurate pressure profile along the calciner height, having a maximum difference of 15 mbar (12% of the total experimental pressure drop) with the experiments. In addition, the CO2 mass fraction at the outlet is successfully predicted with an error of only 3%. Concerning the heat flux, a mesh independent solution with computationally affordable grid size was not possible due to the thin thermal boundary layer, which has also been reported in all relevant research. Nevertheless, the provided solution was found to be almost mesh independent hydrodynamically. For this reason, an estimation of the heat transfer coefficient of the heat pipe heat exchanger was made by using several 0-D mechanistic models, which take as input hydrodynamic data obtained from CFD. As a follow-up, the CFD model combined with the empirical heat transfer correlations is indicatively used to parametrically investigate the effect of fluidization velocity on the heat transfer coefficient of the heat pipe heat exchanger. Through this study, this paper sheds important light on the effect of hydrodynamics on the radiative and convective components of heat transfer. It is shown that a 20% change in fluidization velocity will mildly (¡2%) affect the total heat flux, due to its counterbalancing effect on the radiative and convective components. Peer reviewed

Climate change, desertification, salinisation of soils and the changing hydrology of the Earth are creating or modifying microbial habitats at all scales including the oceans, saline groundwaters and brine lakes. In environments that are saline or hypersaline, the biodegradation of recalcitrant plant and animal polysaccharides can be inhibited by salt‐induced microbial stress and/or by limitation of the metabolic capabilities of halophilic microbes. We recently demonstrated that the chitinolytic haloarchaeon Halomicrobium can serve as the host for an ectosymbiont, nanohaloarchaeon ‘ Candidatus Nanohalobium constans’. Here, we consider whether nanohaloarchaea can benefit from the haloarchaea‐mediated degradation of xylan, a major hemicellulose component of wood. Using samples of natural evaporitic brines and anthropogenic solar salterns, we describe genome‐inferred trophic relations in two extremely halophilic xylan‐degrading three‐member consortia. We succeeded in genome assembly and closure for all members of both xylan‐degrading cultures and elucidated the respective food chains within these consortia. We provide evidence that ectosymbiontic nanohaloarchaea is an active ecophysiological component of extremely halophilic xylan‐degrading communities (although by proxy ) in hypersaline environments. In each consortium, nanohaloarchaea occur as ectosymbionts of Haloferax , which in turn act as scavenger of oligosaccharides produced by xylan‐hydrolysing Halorhabdus . We further obtained and characterised the nanohaloarchaea–host associations using microscopy, multi‐omics and cultivation approaches. The current study also doubled culturable nanohaloarchaeal symbionts and demonstrated that these enigmatic nano‐sized archaea can be readily isolated in binary co‐cultures using an appropriate enrichment strategy. We discuss the implications of xylan degradation by halophiles in biotechnology and for the United Nation's Sustainable Development Goals. International audience

Already today engine emissions from medium speed engines operating in protected areas or used for special applications are subject to ambitious emission reduction requirements. The driving force behind such requirements is not necessarily from regulatory bodies, but rather commercial, stemming from green operators or investors. Publicly exposed applications like passenger ships or the growing offshore wind turbine industry are two good examples. The emission targets are derived from the most stringent non-road mobile machinery emission rules. Unlike in IMO regulation, not only nitrogen oxides (NOX) but also carbon monoxide (CO), hydrocarbons (HC), particulate matter on mass (PM) and number (PN) base are limited due to their health and environmental impact. Building on our previously presented study to optimize a combined medium speed engine andaftertreatment system package for best fuel consumption and emission performance, we present our testing results of combining the ABC DZC engine family (1-4 MW) with a Hug Engineering DPF+SCR system yielding unprecedented ultra low emissions. On the engine testbed, a 2 MW ABC DZC series engine was combined with a modular Hug exhaust gas aftertreatment system consisting of a diesel particulate filter (DPF) with active regeneration and a selective catalytic reduction (SCR) system with the possibility to include also an oxidation catalyst. Inorder to achieve the challenging emission requirements as well as to optimize overall operating costs, the engine was de-tuned from its original IMO Tier II settings to a fuel efficiency optimized low PM emission setting. This was only possible at the expense of increased engine-out NOX emissions, which were reduced by the SCR system down to EU Stage V levels and further below. Variations of engine- and aftertreatment-setups were tested on full scale in generator and propeller operation mode cycles, yielding a robust concept to achieve well-below EU Stage V emission limits. Detailed investigations during our test campaigns concerning sub 23 nm particle emissions and black carbonrevealed even cleaner exhaust than seen today by DF LNG engines. The presented assembly is the first MW-sized medium speed engine to be certified according to EU Stage V and for the new Bureau Veritas notation “ultra low emission vessel” (ULEV). For further CO2 emission reductions beyond the ones achieved via the fuel consumption savings, the entire system was chosen to consist of biofuel- and synthetic-fuel-ready components, which is one of the next steps to reduce the overall impact for the environment. This novel concept of an ultra low emission medium speed diesel engine was chosen to be implemented as a propulsion and power system into a latest generation wind turbine installation vessel containing 25 MW total installed power which will be presented as well.

AbstractBackgroundChronic obstructive pulmonary disease (COPD) is a complex disorder with a high degree of interindividual variability. Gastrointestinal dysfunction is common in COPD patients and has been proposed to influence the clinical progression of the disease. Using the presence of bile acid(s) (BA) in bronchoalveolar lavage fluid (BAL) as a marker of gastric aspiration, we evaluated the relationships between BAs, clinical outcomes, and bacterial lung colonisation.MethodsWe used BAL specimens from a cohort of COPD patients and healthy controls. Bile acids were profiled and quantified in BAL supernatants using mass spectrometry. Microbial DNA was extracted from BAL cell pellets and quantified using qPCR. We profiled the BAL microbiota using an amplicon sequencing approach targeting the V3-V4 region of the 16S rRNA gene.ResultsDetection of BAs in BAL was more likely at earliest clinical stages of COPD and was independent of the degree of airway obstruction. BAL specimens with BAs demonstrated higher bacterial biomass and lower diversity. Likewise, the odds of recovering bacterial cultures from BAL were higher if BAs were also detected. Detection of BAs in BAL was not associated with either inflammatory markers or clinical outcomes. We also observed different bacterial community types in BAL, which were associated with different clinical groups, levels of inflammatory markers, and the degree of airway obstruction.ConclusionDetection of BAs in BAL was associated with different parameters of airway ecology. Further studies are needed to evaluate whether BAs in BAL can be used to stratify patients and for predicting disease progression trajectories.