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Fuel Production and Transport Chain for Aviation: an Environmental and Economic Comparison of LH2, SAF and Fossil Kerosene
Get PDFThe poster presents climate impacts and costs of the production and transportation pathway for liquid hydrogen and a sustainable jet fuel produced via the Fischer-Tropsch process in comparison to fossil kerosene production. Different electricity scenarios and different electrolyser-carbon capture units and transport means have been investigated
Holographic detection for fast fringe projection profilometry of deep micro-scale objects
Get PDFPhase-shifting Fringe projection profilometry (FPP) excels in 3D measurements for many macro-scale applications, but as features-of-interest shrink to the microscopic scale, depth-of-field limitations slow measurements and necessitate mechanical adjustments. To address this, we introduce digital holography (DH) for fringe image capture, enabling numerical refocusing of defocused object regions. Our experiments validate this approach and compare depth measurement noise with other DH and FPP methods. Results show that for slight defocus, incoherent FPP surpasses coherent techniques, while under significant defocus, the new method minimizes measurement uncertainty and matches the performance of other DH techniques, facilitating faster measurement of deep, micro-scale objects
Observations and systematic documentation of bright/bluish materials within the cavity and ejecta of recent low-latitude impact craters on Mars
Get PDFImpact craters serve as valuable natural probes for investigating the subsurface composition of Mars and other planetary bodies. Large impact events excavate material from deep within the crust, often exposing that material in central uplifts or pits, and were more prevalent during the earlier stages of Mars’ geologic evolution. In contrast, more recent impacts tend to be smaller in scale but can still expose subsurface materials from the uppermost few meters, depending on the size of the event. High-resolution visible observations of ice in the crater rims and ejecta from a subset of such impacts (e.g., Dundas et al., 2021) supported by measurements from instruments like the Mars Odyssey gamma ray/neutron spectrometer (e.g., Boynton et al., 2002; Pathare et al., 2018) and radar (e.g., Mouginot et al., 2010; Putzig et al., 2014), have provided constraints on the distribution and abundance of shallow subsurface water ice. These studies generally indicate the presence of water ice at depths of a few centimeters to meters, primarily restricted to the high- to mid-latitudes, with the most equatorward confirmed ice-bearing crater located at 35.2°N (Posiolova et al., 2022; Dundas et al., 2023), where ice was excavated from depths of ~2-8m (Dundas et al., 2023; Wojcicka et al. 2024).
The High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (McEwen et al., 2007) continues to acquire high-resolution images of small, date-constrained impact craters, including those located equatorward of 35° N/S, often as a follow-up to detections by the Context Camera (CTX; Malin et al., 2007). Some of these impacts also exhibit relatively blue-toned materials within the crater walls or ejecta blankets, although most of these features have not been documented systematically. This work attempts to create a high-resolution inventory of all such equatorial impacts observed by HiRISE, with an aim to help characterize the spectral and morphological properties of the exposed bluish materials and assess their possible compositional origins
Simulation and Experimental Study of Wing Foils for Wind-Assisted Ship Propulsion in an Atmospheric Boundary Layer and Twisted Wind Flow
No full textThis thesis investigates the aerodynamic behaviour of sails in a boundary-layer wind tunnel with twisted wind flow.
In this context, "twist" refers to the change of apparent wind angle along the sail height caused by the sail's movement within the atmospheric boundary layer. Wind tunnel experiments were carried out at FH Kiel using a NACA 0010 wing, covering a range of wind velocities, twist angles, and a complete sweep of angles of attack from 0° to 180°. Streamwise and transverse velocity measurements resolved the boundary layer and the twisted wind flow of the wind tunnel. CFD simulations using the Reynolds-averaged Naver-Stokes (RANS) code STAR-CCM+ were performed to replicate the experiments and theoretical velocity profiles. The combined analysis revealed the influence of twist, transition, and 3D effects on sail performance. For a representative test case a thrust reduction of 17% was
calculated. While the experiments provided physical insights into lift generation and stall, the simulations clarified the sensitivity of CFD to mesh resolution, turbulence modelling, and boundary conditions. A direct comparison of both approaches highlighted areas of agreement as well as systematic deviations, offering guidance for the future application of CFD to wind-assisted ship propulsion
Electrifying Inland Waterway Transport in Germany
Get PDFBattery electric propulsion represents a highly promising avenue for the decarbonization of inland waterway transport. This presentation thus examines the potential for electrifying IWW vessels using their operational profile derived from Automatic Identification System (AIS) data.The findings suggest that battery-electric and hybrid propulsion systems in particular already offer significant potential for reducing direct greenhouse gas (GHG) emissions from inland waterway vessels. The necessary charging powers typically fall within the range of 100 to 200 kW, which would allow for intermodal charging stations. It may also be feasible to implement fully electric propulsion systems for a proportion of the inland waterway fleet. In particular, small passenger vessels such as ferries exhibit considerable potential in this respect
STraM: A strategic network design model for national freight transport decarbonization
Get PDFNational freight transport models are valuable tools for assessing the impact of various policies and investments on achieving decarbonization targets under different future scenarios. However, these models struggle to address several critical elements necessary for strategic planning, such as the development and adoption of new fuel technologies over time, inertia in transport fleets, and uncertainty surrounding future transport costs. In this paper, we develop a strategic network design model, named STraM, that explicitly incorporates these key factors. STraM, being a two-stage stochastic program, effectively handles long-term uncertainty by considering different future scenarios in its decision-making process.It provides a network design plan that includes infrastructure investments and fuel technology decisions, aiming to achieve cost-effective decarbonization of the freight transport system. The model output can be used as input for higher-resolution national freight transport models to yield results with greater operational detail. We demonstrate the application of STraM through a case study of Norway, offering valuable insights into the strategic planning of decarbonizing freight transport
Space weathering on Vesta: Ion bombardment induced changes on HEDs in visible and infrared reflectance
Get PDFThe NASA/Dawn mission targeted V-type asteroid (4) Vesta between 2011 and 2012. The mission confirmed Vesta as the parent body of most of the HED meteorite family and led an extensive mapping of the surface's spectral properties. The well-pronounced different spectroscopic features of Vesta suggest that this body has its own form of space weathering. In this work, we look for the optimal parameter space for distinguishing between fresh and weathered materials on Vesta and other V-type objects. We emulated the effects of the solar wind component of space weathering by performing ion bombardment experiments with 40 keV He+ on four HED meteorites. We then studied the spectral behavior of our artificially weathered samples, spanning from the visible to the mid-infrared range, using several spectral parameters. We observed that in the visible and near-IR range, the evolution of eight parameters – darkening of reflectance at 380–465-550 nm, decrease in band depth and band area of the 1-μm absorption feature, and reddening of three different spectral slopes - are enough to distinguish between differences in mineral composition and weathering state among our samples. In the mid-IR, we detected a consistent red shift in the position of the Reststrahlen feature, associated with sample weathering. These findings can provide support for the interpretation of remote sensing data from V-type objects, aiding in the assessment of mineralogical differences and the weathering state of surface materials
Embedded System for Mobile Laser-based Stand-off Spectroscopy
No full textFast and reliable detection of potentially hazardous chemical, biological and explosive substances from intended or accidental output is crucial to reduce the amount of injuries, as well as to support first responders. Recent terrorist attacks and pandemics emphasize the need for robust solutions and justify the increased research on detection systems for these substances. Spectroscopy systems may prove to be a useful addition to already established systems due to their capability to detect these substances from a distance. Adding mobility, for instance, by mounting such systems on a moving robot, makes them more flexible and utilizable for a larger number of versatile environments and scenarios. This thesis presents the development of the required support electronics and software for a compact laser-induced fluorescence spectroscopy detection unit optimized for the use on mobile platforms. This includes an autofocus module, a pan-tilt platform for spatial orientation, and a georeference
system for localization and attitude determination, together with temperature control and other additional features. All subsystems have been individually validated to ensure proper functionality
