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Joule heating scaling in thermosphere-ionosphere models compared to EISCAT incoherent scatter radar measurements
Full text linkThe polar plasma convection originates from the interaction between the interplanetary magnetic field and the Earth’s magnetic field. To model the atmosphere-ionosphere system, the resulting polar electric potential is taken as an upper boundary condition using empirical convection models. These empirical models cannot represent short-term variations of the electric field which has been shown to cause a systematic underestimation of ionospheric Joule heating rates at high latitudes. Commonly, atmosphere-ionosphere models apply a Joule heating scaling factor for compensation. For example, a constant scaling factor of 1.5 is applied in the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIE-GCM). We evaluate the accuracy of this constant scaling factor by comparing Joule heating rates calculated
from the TIE-GCM with those estimated from measurements by the EISCAT incoherent scatter radar in Tromsø, Norway (69.6°N, 19.2°E). We investigate TIE-GCM runs driven with the Heelis, Weimer, and AMIE convection models, as well as WACCM-X model runs in standard and high resolution. We show that the required scaling factor varies significantly with geomagnetic activity, solar wind energy input, magnetic local time, and the applied plasma convection model. The impact of the spatial and temporal model resolution on the Joule heating rates is studied as well
Validation of the DLR dual stream jet noise test rig at the Aeroacoustic Wind Tunnel Braunschweig
Full text linkSince its refurbishment in 2019, DLR's dual stream jet noise test rig has seen many long cowl and short cowl experiments powered by the DNW-NWB 1.4MW screw compressor air supply (3kg/s, 6bar.g). The tremendous jet diameters of 80-100mm enable the installation of well-sized wing models, but cause a rather large (i.e. non-pointwise) source distribution in the mid-sized test room. The knowledge of the source distribution allows AWB to achieve good comparison of their Rmic/Djet=20 data to conventionally measured large-scale far-field data (Rmic/Djet=100), to build advanced engine models and to optimize its instrumentation for testing large models in small test rooms. The rig capabilities and limits due to engine model size (using jet diameters of 31.5mm, 50mm, 80mm) as well as internal and external rig noise were recently determined and evaluated with help of contemporary evaluation techniques. All in all, this presentation is meant to help understand how to design a test and the instrumentation for large models in small test rooms, considering the limitations of the test facility
Multispectral to Hyperspectral using Pretrained Foundational Model
Full text linkHyperspectral imaging provides detailed spectral information, offering significant potential for monitoring greenhouse gases like CH4 and NO2. However, its application is constrained by limited spatial coverage and infrequent revisit times. In contrast, multispectral imaging delivers broader spatial and temporal coverage but lacks the spectral granularity required for precise GHG detection.
To address these challenges, this study proposes Spectral and Spatial-Spectral transformer models that reconstructs hyperspectral data from multispectral inputs. The models in this paper are pretrained on EnMAP and EMIT datasets and fine-tuned on spatio-temporally aligned (Sentinel-2, EnMAP) and (HLS-S30, EMIT) image pairs respectively. Our model has the potential to enhance atmospheric monitoring by combining the strengths of hyperspectral and multispectral imaging systems
Stress Response of Aspergillus niger Spores to Copper Surfaces and the Implications for Antifungal Surface Functionalization
Full text linkFungal contaminations pose a persistent challenge in the fields of healthcare,
agriculture, and industry, primarily due to their environmental adaptability
and increasing resistance to antifungal agents. In this study Aspergillus niger
is utilized as model organism. This work evaluates copper, brass, and steel
surfaces functionalized with ultrashort pulsed laser-induced periodic surface
structures (USP-DLIP) designed as 3 and 9 μm topographies. Fungal spore
viability assays show that 9 μm periodicities on copper surfaces achieve a
99% reduction in spore viability, indicating that increased copper ion release is
a key factor in enhanced antifungal effectivity. Scanning electron microscopy
(SEM) analysis confirm substantial spore damage, linked to the viability
testing and the measured copper ion release by inductively coupled plasma
triple quadrupole mass spectrometry (ICP-QQQ) spectrometry. Interestingly,
9 μm structured steel surfaces reveal a trend toward antifungal activity despite
their inert nature. Whereas structured brass surfaces do not show significant
improvement in antifungal activity. These findings suggest USP-DLIP
structuring on copper and stainless-steel surfaces have considerable potential
for antifungal applications, although interactions between surface structures,
released ions, and fungal spores are highly complex. Yet, USP-DLIP
offers promising advantages for developing advanced antifungal materials
Potential of Earth Observation for the German North Sea Coast—A Review
Full text linkRising sea levels, warming ocean temperatures, and other climate change impacts threaten the German North Sea coast, making monitoring of this system even more critical. This study reviews the potential of remote sensing for the German North Sea coast, analyzing 97 publications from 2000 to 2024. Publications fell into four main research topics: coastal morphology (33), water quality (34), ecology (22), and sediment (8). More than two-thirds of these papers (69%) used satellite platforms, whereas about one third (29%) used aircrafts and very few (4%) used uncrewed aerial vehicles (UAVs). Multispectral data were the most used data type in these studies (59%), followed by synthetic aperture radar data (SAR) (23%). Studies on intertidal topography were the most numerous overall, making up one-fifth (21%) of articles. Research gaps identified in this review include coastal morphology and ecology studies over large areas, especially at scales that align with administrative or management areas such as the German Wadden Sea National Parks. Additionally, few studies utilized free, publicly available high spatial resolution imagery, such as that from Sentinel-2 or newly available very high spatial resolution satellite imagery. This review finds that remote sensing plays a notable role in monitoring the German North Sea coast at local scales, but fewer studies investigated large areas at sub-annual temporal resolution, especially for coastal morphology and ecology topics. Earth Observation, however, has the potential to fill this gap and provide critical information about impacts of coastal hazards on this region
Flood risks in Hue, Central Viet Nam: An assessment of flood hazards, exposures, vulnerabilities, root causes and impacts
Full text linkWith its long coastline and dense populations along rivers and coastal zones, Viet Nam is one of the world’s countries most affected by floods. Thua Thien Hue province in Central Viet Nam is one region that is particularly prone to flooding as it has two to three floods of varying severity each year, which cause significant damage to people, infrastructure and nature. To effectively reduce future flood impacts and enhance the region’s resilience to floods, it is crucial to understand flood risk drivers and how they progress to the adverse impacts. These include identifying flood-prone areas, understanding who and what is in these areas, that is, exposed to floods (e.g. people or infrastructure), and determining how exposed people and elements are vulnerable to harm from floods. However, this information is currently unavailable in the region, hindering effective risk management. This report addresses this need with insights into the complex nature of flood risks for the urban region of Hue, and recommendations for comprehensive and sustainable flood risk management and adaptation strategies at the catchment level, including risk-informed spatial development planning. More specifically, this report provides an overview of past flood events and their impacts on the region (see chapter 2), an in-depth analysis of key flood impacts on people, livelihoods, transport and water quality, including risk drivers, root causes and interconnections (see chapter 3), an outlook on future flood risks in Hue (see chapter 4), and entry points for comprehensive flood risk management and adaptation (see chapter 5). The report concludes with a summary and an outlook (see chapter 6)
Assessing the Feasibility of Persistent Scatterer Data for Operational Dam Monitoring in Germany: A Case Study
Full text linkMulti-temporal synthetic aperture radar interferometry (MT-InSAR) has evolved from a niche research technique into a powerful global monitoring tool. With the launch of nationwide and continent-wide ground motion services (GMSs), freely available deformation data can now be analyzed on a large scale. However, their applicability for monitoring critical infrastructure, such as dams, has not yet been thoroughly assessed, and several challenges have hindered the integration of MT-InSAR into existing monitoring frameworks. These challenges include technical limitations, difficulties in interpreting deformation results, and the rigidity of existing safety protocols, which often restrict the adoption of remote sensing techniques for operational dam monitoring.
This study evaluates the effectiveness of persistent scatterer (PS) data from the German ground motion service (Bodenbewegungsdienst Deutschland, BBD) in complementing time-consuming in situ techniques. By analyzing a gravity dam in Germany, BBD time series were compared with in situ pendulum data. We propose a two-stage assessment procedure: First, we evaluate the dam’s suitability for PS analysis using the CR-Index to identify areas with good radar visibility. Second, we assess the interpretability of BBD data for radial deformations by introducing a novel index that quantifies the radial sensitivity of individual PS points on the dam. This index is universally applicable and can be transferred to other types of infrastructure.
The results revealed a fair correlation between PS deformations and pendulum data for many PS points (up to R² = 0.7). A priori feasibility assessments are essential, as factors such as topography, land cover, and dam type influence the applicability of the PS technique. The dam’s orientation relative to the look direction of the sensor emerged as a key criterion for interpreting radial deformations. For angle differences (ΔRAD) of up to 20° between the true north radial angle of a PS point and the satellite’s look direction, the line-of-sight (LOS) sensitivity accounts for approximately 50 to 70% of the true radial deformation, depending on the satellite’s incidence angle. This criterion is best fulfilled by dams aligned in a north–south direction.
For the dam investigated in this study, the LOS sensitivity to radial deformations was low due to its east–west orientation, resulting in significantly higher errors (6 mm ≤ RMSE ≤ 43 mm) compared to in situ pendulum data. Eliminating PS points with an unfavorable alignment with the sensor should be considered before interpreting radial deformations. For implementation into operational monitoring programs, greater effort must be spent on near-real-time updates of BBD datasets
Effect of manufacturing conditions on the mechanical behaviour of short fibre reinforced PA6 parts manufactured with screw extrusion additive manufacturing
No full text3D printing has been increasingly used in aeronautical and automotive industry for the production of integral metallic or fibre-reinforced plastic (FRP) parts. Various additive manufacturing methods have been developed to respond to the growing industrial needs. The Screw Extrusion Additive Manufacturing (SEAM) is a pellet-based production technique relying on a heated screw extruder. This heated single screw extruder facilitates the plasticisation of injection-moulding granules and direct extrusion of high temperature thermoplastics. The mechanical properties of the 3D-printed part depend directly on adjustable process parameters, making process optimisation a strongly empirical task. To gain a solid comprehension of the process, the present article focuses on a first extensive characterization of a carbon fibre reinforced PA6 thermoplastic material with a fixed set of manufacturing parameters. The material anisotropy and fibre characteristics are first analysed on polished micrograph samples. In-situ specimens are extracted from 3D-printed parts and mechanically tested under tension, compression and bending in different material directions. In particular, the work focuses on the investigation of failure patterns through the use of the Digital Image Correlation (DIC) technique. In light of the experimental results, the article discusses potential improvements of the mechanical properties through the optimisation of manufacturing parameters