KITopen
Not a member yet
63711 research outputs found
Sort by
Impacts on and damage to European forests from the 2018–2022 heat and drought events
Get PDFDrought and heat events in Europe are becoming
increasingly frequent due to human-induced climate change,
impacting both human well-being and ecosystem function-
ing. The intensity and effects of these events vary across the
continent, making it crucial for decision-makers to under-
stand spatial variability in drought impacts. Data on drought-
related damage are currently dispersed across scientific pub-
lications, government reports, and media outlets. This study
consolidates data on drought and heat damage in European
forests from 2018 to 2022, using Europe-wide datasets in-
cluding those related to crown defoliation, insect damage,
burnt forest areas, and tree cover loss. The data, covering
16 European countries, were analysed across four regions,
northern, central, Alpine, and southern, and compared with a
reference period from 2010 to 2014.
Findings reveal that forests in all zones experienced re-
duced vitality due to drought and elevated temperatures, with
varying severity. Central Europe showed the highest vulner-
ability, impacting both coniferous and deciduous trees. The
southern zone, while affected by tree cover loss, demon-
strated greater resilience, likely due to historical drought ex-
posure. The northern zone is experiencing emerging impacts
less severely, possibly due to site-adapted boreal species,
while the Alpine zone showed minimal impact, suggesting
a protective effect of altitude.
Key trends include (1) significant tree cover loss in the
northern, central, and southern zones; (2) high damage lev-
els despite 2021 being an average year, indicating lasting ef-
fects from previous years; (3) notable challenges in the cen-
tral zone and in Sweden due to bark beetle infestations; and
(4) no increase in wildfire severity in southern Europe despite
ongoing challenges.
Based on this assessment, we conclude that (i) European
forests are highly vulnerable to drought and heat, with even
resilient ecosystems at risk of severe damage; (ii) tailored
strategies are essential to mitigate climate change impacts on
European forests, incorporating regional differences in for-
est damage and resilience; and (iii) effective management re-
quires harmonised data collection and enhanced monitoring
to address future challenges comprehensively
Separation of Short-Chain Fatty Acids from Primary Sludge into a Particle-Free Permeate by Coupling Chamber Filter-Press and Cross-Flow Microfiltration: Optimization, Semi-Continuous Operation, and Evaluation
Get PDFShort-chain fatty acids (SCFAs) are valuable metabolic intermediates that are produced during dark fermentation of sludge, which, when capitalized on, can be used as chemical precursors for biotechnological applications. However, high concentrations of solids with SCFAs in hydrolyzed sludge can be highly detrimental to downstream recovery processes. This pilot-scale study addresses this limitation and explores the recovery of SCFAs from primary sludge into a particle-free permeate through a combination of chamber filter-press (material: polyester; mesh size: 100 μm) and cross-flow microfiltration (material: α-AlO; pore size: 0.2 μm; cross-flow velocity: 3 m·s; pressure = 2.2 bars). Firstly, primary sludge underwent dark fermentation yielding a hydrolyzate with a significant concentration of SCFAs along with total solids (TS) concentration in the range of 20 to 30 g·L. The hydrolyzate was conditioned with hydroxypropyl trimethyl ammonium starch (HPAS), and then dewatered using a filter press, reducing TS by at least 60%, resulting in a filtrate with a suspended solids concentration ranging from 100 to 1300 mg·L. Despite the lower suspended solids concentration, the microfiltration membrane underwent severe fouling due to HPAS’s electrostatic interaction. Two methods were optimized for microfiltration: (1) increased backwashing frequency to sustain a permeate flux of 20 L·m·h (LMH), and (2) surface charge modification to maintain the flux between 70 and 80 LMH. With backwashing, microfiltration can filter around 900 L·m (without chemical cleaning), with the flux between 50 and 60 LMH under semi-continuous operation. Evaluating the particle-free permeate obtained from the treatment chain, around 4 gC·capita·d can be recovered from primary sludge with a purity of 0.85 to 0.97 C·DOC
NaDFOB and FEC as Electrolyte Additives Enabling Improved Cyclability of Sodium Metal Batteries and Sodium Ion Batteries
Get PDFSodium metal is often considered as an anode material to improve the energy-density of sodium metal batteries (SMB) respectively sodium ion-based batteries (SIB). However, the active Na metal anode is a particular challenge. To formulate a suitable electrolyte has therefore been a key issue to stabilize sodium metal anodes. Here we report additive strategies by using the additives sodium difluoro(oxalato) borate (NaDFOB) or/and fluoroethylene carbonate (FEC) in the baseline electrolyte
solution of 1 M NaPF6 in ethylene carbonate/propylene carbonate to overcome these issues. For the SMB with sodium anode and carbon-coated Na3V2(PO4)3 (NVP) cathode, a stable cell cycling up to 600 cycles (capacity retention about 96�3%) was reached by using only 1–2 wt. % NaDFOB, compared to only less than 75 cycles of the baseline electrolyte. Sodium plating/stripping tests, voltammetry measurements, impedance analysis as well as cell tests were performed in order to reveal
the electrochemical characteristics of the electrolytes including additive effects. The optimal SIB cell performance in cells containing hard carbon and NVP was achieved by using 2 wt.-% NaDFOB. NaDFOB electrolyte can be considered as a beneficial additive for Na metal cell and its application could be also extended for full SIBs
Broad-band, high-gain, low-frequency antennas for radio detection of earth-skimming tau neutrinos
Get PDFA promising approach to detect high-energy tau neutrinos is through the measurement of
impulsive radio emission from horizontal air showers initiated in the Earth’s atmosphere. Observations
at frequencies between 30 and 80 MHz seem particularly promising — if high-gain antennas focused
at the horizon and blocking out as much as possible of the noisy sky are employed. Due to the large
wavelengths, however, designing an antenna with the required properties is highly non-trivial at such
low frequencies. In this article, we explore suitable antenna designs that provide the desired high
gain, possess a smooth beam, are insensitive to ground conditions, are easily impedance-matched
over the wide band, and are mechanically simple for deployment in large numbers in inaccessible
terrain. In particular, we consider the “rhombus” antenna design for both horizontally and vertically
polarized radiation a very attractive option for tau neutrino detection efforts in the atmosphere
with the radio technique
The Novel Coupling of Operando Methods: Electrochemical Dilatometry with Mass Spectrometry Using the Example of a Li|Graphite Half Cell
Get PDFThe aging of lithium-ion cells critically affects their lifetime, safety, and performance, particularly due to electrode and electrolyte degradation. This study introduced a novel combined-measurement cell-integrating operando dilatometry and operando mass spectrometry to observe real-time physical and chemical changes during electrochemical cycling. Operando dilatometry measures thickness changes in the working electrode, while operando mass spectrometry analyzes gas emissions to provide insights into the underlying degradation processes. The results indicated significant correlations between electrochemical behavior, thickness changes, and gas evolution, revealing both the reversible and irreversible growth of constituents on particles and the electrode surface. The formation of the solid electrolyte interphase due to the degradation of electrolyte components, such as solvents or conductive salts, is identified as a key factor contributing to irreversible changes. The operando gas analysis highlighted the presence of decomposition intermediates and products, which are all linked to electrolyte degradation. Additionally, post-mortem gas chromatography coupled with mass spectrometry identified several compounds, confirming the presence of different decomposition pathways. This integrated and holistic approach deepened the understanding of the aging mechanisms at the electrode level
Deep learning for augmented process monitoring of scalable perovskite thin-film fabrication
Get PDFReproducible large-area fabrication is one of the remaining challenges for the commercialization of perovskite photovoltaics. Imaging methods augmented with deep learning (DL) enable in-line detection of spatial or temporal inconsistencies and predict the impact of observed changes on device performance. In this work, we showcase three use cases of how DL augments complex experimental data analysis of the large-area perovskite thin film formation, even on moderate-sized datasets. First, we demonstrate material composition monitoring by differentiating between precursor property variations, ensuring material consistency during fabrication. Second, we provide early thin-film quality assessment by predicting holistic device performance even before its finalization. Finally, we extend the approach from parameter prediction to generating recommendations for process control by forecasting monitoring signals as a function of a variable process parameter and predicting the corresponding device performances. By addressing tasks that are hardly possible for humans to solve, we present how DL augments data analysis by transforming experimental data into predictions of target parameters
Accuracy of an articulated head-and-neck motion model using deep learning-based instance segmentation of skeletal bones in CT scans for image registration in radiotherapy
Get PDFMonitoring the Fate of Zn in the Cu/ZnO/ZrO Catalyst during CO‐to‐Methanol Synthesis at High Conversions by Operando Spectroscopy
Get PDFStrategy for Fabricating Multiple-Shape Memory Polymeric Materials Based on Solid State Mixing
Get PDFTraditionally, multiple shape memory polymers (multiple-SMPs) are created by forming either immiscible blends with high phase continuity (cocontinuous or multilayer phase morphology) or miscible blends that exhibit compositional heterogeneity at the nanoscale. Here, a new strategy for the fabrication of multiple-SMPs is proposed. It consists of the possibility of homogeneous mixing of immiscible polymers in the solid state under high pressure and shear deformation conditions. The blends formed in this way exhibit homogeneity of mixing down to the nanoscale, up to 40–95 nm. The transition from immiscible to miscible blends leads to an improvement not only in shape memory but also in the mechanical performance of the blends formed. Polypropylene (PP) and polystyrene (PS) were selected as pairs of immiscible polymers. The method of solid phase mixing is high pressure torsion (HPT). It was shown that the HPT-processed 50% PP/50% PS blend is able to exhibit an excellent triple shape memory effect (shape fixation of ∼94–95%, and recovery of ∼85–95%) with widely tunable (low and high) transition temperatures