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Drone-Based Quantification of Soiling Losses for Heliostats in Solar Power Tower Plants
No full textMonitoring soiling levels at many positions in the solar field can help to optimise cleaning schedules and reduce resources invested. Image-based methods, such as the one presented in this work, are currently being developed.
In this study, we present a drone-image-based measurement approach capable of providing spatially resolved information on the soiling losses across the entire solar field. The method is applied during the plant operation in sunny conditions using a commercially available drone
Acoustic experiments for special forces helicopter operations
No full textFor military missions the helicopter is a versatile aircraft with many benefits. However, the high levels of noise radiation enable large acoustic detection ranges. For mission success, knowledge of the acoustic radiation and propagation is paramount. This paper describes the results of acoustic measurements for a helicopter that is typically used for operations by the German special forces. The measurements include identification of the global noise radiation during different flight conditions, determination of time between acoustic detection and arrival at the target location and determination of the acoustic detection distance. Different approach and departure procedures were executed and the acoustic radiation was measured. Results indicate that during approach the most noise is generated either at the transition from steady level flight to descent/deceleration or at the end of the flare procedure. For the helicopter considered here, a left turn departure generates more noise at a target location then a right turn departure
Online monitoring of Solvent Based Recycling
No full textIn this thesis, a study of dielectric spectroscopy and ultrasonic sensing is carried out to determine their potential in solvent-based recycling of Elium® thermoplastic composites
Urban Science with a View from Space - Dynamics, Dimensions, Patterns, Effects, Adaptation, Ethics
No full textIm Jahr 2024 lebten 58 % der Weltbevölkerung in Städten. Städte, ob groß oder klein, sind der primäre Lebensraum für mehr als die Hälfte der Menschen und sie fungieren als politische, soziale, wirtschaftliche, kulturelle und ökologische Zentren. Mit der Art und Weise, wie wir die gebauten Strukturen und die Nutzungsmuster gestalten, haben wir einen direkten Einfluss auf verschiedene Variablen. Auf individueller Ebene bestimmen die Strukturen den Alltagsrhythmus, das Verhalten und die Wahrnehmung. Auf gesellschaftlicher Ebene zeigt sich die Relevanz der räumlichen Strukturen in ihren Auswirkungen auf den Flächenverbrauch, die Treibhausgasemissionen, den städtischen Wärmeinseleffekt, die Art der Mobilität und viele andere Themen. In den letzten Jahren haben die rasanten Entwicklungen in der Datentechnologie, der Rechenleistung und den Methoden in der Fernerkundung und anderen geografischen Bereichen es ermöglicht, urbane Strukturen mit einer noch nie dagewesenen Menge an Daten empirisch und global zu analysieren. In diesem Forschungsbericht wird die gebaute urbane Landschaft auf unserem Planeten in ihrer zeitlichen Entwicklung dokumentiert, die entstehende Dynamik systematisiert, urbane Formen verglichen, Auswirkungen der entstehenden räumlichen Muster bewertet und Möglichkeiten der städtischen Anpassung vorgestellt. Ein grundlegendes Thema ist der Begriff 'urban' an sich, wie er theoretisch und konzeptionell definiert wird und wie er raumbezogen gemessen und kartiert werden kann. Zudem werden die methodischen und thematischen Arbeiten auch unter ethischen Gesichtspunkten bewertet. Der Forschungsbericht basiert auf 24 veröffentlichten Arbeiten und einer Synthese, die aus den Einzelstudien eine Roadmap für zukünftige Forschungsrichtungen der urbanen Fernerkundung schafft
Lunar volcanism: A Geophysical perspective
No full textThe lunar crust has preserved a record of the Moon’s volcanic and magmatic activity through time. While the extrusive maria dominate the volcanic record, little is known regarding their thickness and the details of their emplacement. Intrusive activity is even more elusive, with most intrusions expressing little to no surface signature. Here, we present a global investigation and a volumetric inventory of extrusive and intrusive volcanic materials (Broquet & Andrews-Hanna, 2024a, 2024b). Gravity and topography are inverted using a two-layer loading model under the premise of pre-mare isostasy to constrain mare and cryptomare thickness, as well as updated crustal thickness models. Substantial lateral variations in mare thickness are found, with averages 7.9 km within large mare basins compared to 1.6 km outside of these basins. This important thickness variation associated with minimal change in the surface topography can be explained by some combination of long-distance transport of low viscosity mare and/or a buoyancy control limiting mare eruptions to a constant level surface.
Our inversion predicts the shape of the lunar crust before it got obscured by mare materials. The pre-mare surface of the nearside Oceanus Procellarum region is ~2 km lower than the surroundings, and possible explanations, including a giant impact, pore space annealing, isostatic adjustment, and plume-induced crustal erosion, are discussed. The western part of Imbrium’s ring is not found in the pre-mare topography, implying that it never formed or that some processes erased its signature from gravity and topography. The feldspathic, pre-mare, crust is ~7 km thinner within large nearside basins than in models not accounting for the high-density mare. The pre-fill floor of these basins was ~6 km deeper than currently observed. These new insights have implications for impact simulations that try to reproduce the crustal structure of nearside mare basins.
Our preferred volumes of mare and cryptomare total to 20×106 km3. Investigation of crustal intrusions associated with linear gravity anomalies, floor-fractured craters, ring dikes, graben, and beneath volcanic constructs, yield a total volume of 9×106 km3. The major fraction of intrusive materials is in the form of ring dikes located at the margin of large basins in zones of flexural extension, which indicates an important control of lithospheric stress on magma ascent. Taken together, the total volume of the secondary crust corresponds to ~2% (and up to 5%), of the total lunar crust volume. The combined volume of intrusives and extrusives is found to be 3 times greater in the nearside than in the farside. Intrusive activity dominates in the farside (intrusive:extrusive ratio of 5:2), whereas extrusive volcanism is more pronounced in the nearside (1:5). Both are related to the lunar asymmetry in which the thinner crust and warmer subsurface beneath the Procellarum KREEP terrane enables enhanced melting and magma ascent. The strong asymmetry in melt production supports an early KREEP migration, which must have been established 100 s of Myr before nearside volcanism began to allow for the buildup of heat
Simulation of Daily Charging Needs in Ulm / Neu-Ulm
No full textThe share of electric vehicles is planned to increase to more than 90% in the year 2045. Consequently, the capacity of the energy grid must be accordingly extended. For predicting future loading needs in the cities of Ulm / Neu-Ulm (Germany) and projecting them onto the existing energy grid, a tool chain has been realized, described herein. The resulting simulation system computes the charging needs and interactions between the grid and the vehicle fleet on a disaggregated level of single vehicles, their stops - locations and durations -, and single lines from the cities' energy grid. The results shall help the organization responsible for the energy grid to plan necessary extensions
Numerical heat transfer on highly porous aggregates and asteroid boulders
No full textBased on its recent success, the Hayabusa2 mission (2014-2020) [1] has returned samples of C-type asteroid Ryugu (162173) to Earth, and the sample analysis is currently ongoing [2]. Remote sensing [3] and in-situ [4] data indicate an unexpectedly low thermal inertia for the majority of rocks on Ryugu [5], which has generally been attributed to a high intrinsic porosity. However, results obtained from returned samples indicate much lower porosities. The origin of this discrepancy is currently unknown and different causes, including a potential scale dependence of thermophysical properties, are being discussed [6].
While the general trend of lower thermal conductivity at high porosities seems intuitive, porosity estimates derived from thermal conductivity are currently based on an extrapolation of meteorite properties to large porosities. This is due to the fact that highly porous meteorite samples are lacking in our meteorite collections and it remains to be explored if the applied extrapolation method is physically sound. Furthermore, depending on the applied model, porosity estimates vary widely between 28% and 55% [5]
The Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity (LISTER) on Blue Ghost Mission 1 to Mare Crisium. I. Pneumatic Excavation of Regolith
No full textThe Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity (LISTER) is the first robotically deployed subsurface thermal probe that actively excavates lunar regolith and makes scientific measurements at multiple depths. It was deployed in Mare Crisium on Blue Ghost Mission 1 in 2025 March, reached 1 m depth, and measured the temperature and thermal conductivity of the regolith at eight different depths. The previous depth record for robotic in situ thermal measurements of the Moon was 8 cm. LISTER utilizes the pneumatic excavation technique, blowing a jet of pressurized nitrogen gas, as it pushes its thermal probe into the regolith. The gas expands rapidly in the lunar vacuum and lofts regolith clumps and clasts out of the hole. When the probe reaches one of the depths targeted for thermal measurements, LISTER stops blowing gas and pushes the probe into the yet-to-be-excavated bottom-hole regolith. It completes the necessary thermal measurements in 2 hr and then resumes excavation to the next targeted depth. LISTER detects obstacles on its way by monitoring the weight on bit (WOB). When the WOB exceeds a programmable threshold, LISTER attempts to dislodge the obstacle by automatically performing a piston-like vibratory movement (“dithering”), while it keeps blowing gas. Finally, video-monitoring the ejecta from LISTER’s excavation operations is useful in studying the stratigraphy of the regolith
Molten salt synthesis of increased (100)-facet and polycrystalline nickel oxide nanoparticles for the oxygen evolution reaction: impact of facet and crystallinity on electrocatalysis
No full textNickel oxide nanocubes with increased (100) surface facet presence (NiO(100)) were synthesized through a molten salt synthesis procedure to probe their oxygen evolution reaction (OER) activity in order to investigate the relationship between the surface facet and OER performance. While altering the synthesis parameters to decrease NiO(100) particle sizes and agglomeration, a polycrystalline NiO nanoparticle system formed from using Li2O as a Lux-Flood base (labelled Li2O-MSS NiO, where MSS stands for molten salt synthesis). This novel synthesis was further elaborated and the obtained materials were also tested for OER activity. After thorough structural characterization to determine crystallinity, lattice spacings, and elemental distribution, their OER activity was compared versus high surface area NiO(111) nanosheets in a three-electrode rotating disk electrode (RDE) system. The activity trend of (111) > Li2O-MSS > (100) was observed. This decrease in activity of the nanocube and polycrystalline samples was explained by differences between theoretical and experimental conditions, differences in ink rheology and resulting catalyst layer properties, and significant agglomeration seen in the imaging of the sample. Methods for improving the OER activity of these samples are discussed in the conclusion of this study