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Leveraging open data for energy source selection in bi-valent industrial processes. (2024)
Sejdija, Jonathan ; Maurer, Florian ; Schemm, Ralf ; Kuperjans, Isabel
The transition towards sustainable and efficient energy systems is a major challenge. This is particularly the case for industrial processes, where the choice of energy source has significant economic and environmental consequences.
Evaluation of aeroacoustic optimisation strategies for a generic flight mission of a tilt-propeller aircraft (2025)
Bergmann, Ole ; Möhren, Felix ; Frey, David Aljoscha ; Janser, Frank ; Braun, Carsten
Screening halotolerant bacteria for their potential as plant growth-promoting and coal-solubilizing agents (2025)
Digel, Ilya ; Akimbekov, Nuraly ; Kamenov, Bekzat ; Altynbay, Nazym ; Tastambek, Kuanysh ; Zha, Jian ; Tepecik, Atakan ; Sakhanova, Svetlana K.
The bioconversion of salinized land into healthy agricultural systems by utilizing low-rank coal (LRC) is a strategic approach for sustainable agricultural development. The aims of this study were: (1) to isolate bacterial strains associated with the rhizosphere of native plants in coal-containing soils, (2) to characterize their plant growth-promoting (PGP) and coal-solubilizing capabilities under laboratory conditions and (3) to evaluate their influence on the germination and growth of chia seeds under saline stress. Fourteen bacterial cultures were isolated from the rhizosphere of Artemisia annua L. using culture media containing salt and coal. Based on their PGP activities (nitrogen fixation, phosphate solubilization, siderophore and indole-3-acetic acid production), five strains were selected, belonging to the genera Bacillus, Phyllobacterium, Arthrobacter, and Pseudomonas. Solubilization assays were conducted to confirm the ability of these strains to utilize coal efficiently. Finally, the selected strains were inoculated with chia seeds (Salvia hispanica L.) to evaluate their ameliorating effect under saline stress conditions in coal-containing media. Inoculation with A. subterraneus Y1 resulted in the highest germination and growth metrics of chia seeds. A positive but comparatively weaker response was observed with P. frederiksbergensis AMA1 and B. paramycoides Lb-1 as inoculants. Coal inoculated with halotolerant bacteria can serve as the foundation for humified organic matter in salt-affected environments. The selected halotolerant bacteria enhance coal biotransformation while exhibiting PGP traits.
Laser beam welding of copper under vacuum to extend the process limits (2025)
Schleser, Markus ; Liebe, Philipp ; Gerhards, Benjamin ; Gerhards, Benedikt
This study explores challenges and innovations in laser beam welding of copper, focusing on infrared lasers, beam shaping and laser welding under vacuum (LaVa). Using a Trumpf TruFiber 2000 P and a Trumpf TruDisc 6000 with BrightLine technology, the research examines copper welding under reduced ambient pressure to improve process stability and seam quality. Single-mode welding shows improved stability with reduced melt ejection and minimal to no porosity. High-speed camera observations show unique behaviour for the analysed parameters, such as a smaller molten pool (2.4 to 4.0 times smaller) and capillary expansion (1.7 to 2.7 times larger) under vacuum conditions. BrightLine technology similarly shows a smaller molten pool (2.0 to 3.3 times smaller) and increased stability. While single-mode welding does not significantly increase penetration depth, multimode welding achieves greater penetration depth (up to 34%) at lower welding velocities (50 mm/s) under vacuum. Comparisons between atmospheric and vacuum welding highlight the benefits of the latter, emphasising uniformity and minimal melt ejection. Process stability correlates with weld quality, demonstrating the benefits of vacuum conditions. The combination of vacuum and established welding techniques extends process boundaries, achieving higher stability and seam quality with both types of lasers. The results indicate that vacuum conditions combined with proven welding approaches enhance copper laser welding. The potential for greater stability and improved weld quality under vacuum, particularly in single-mode welding, enables lower welding velocities down to 8.3 mm/s. Lower velocities, associated with higher energy per unit length, enable greater penetration depths.
Damage of masonry infills in February 2023 Kahramanmaras earthquakes and isolation of infill walls ad potential solution for the future (2024)
Marinkovic, Marko ; Butenweg, Christoph
The most dominant type of damage in the February 2023 Kahramanmaras earthquakes was the failure of infills walls. This paper shows just part of the effects of these earthquakes on the infills and concequences on the building inventory and people. The data was collected during the reconaissance field mission one month after the earthquake. In all cities visited damage of the infilled RC frame structures was devastating. Poor behaviour and heavy damage due to the interaction of flexible frames with the stiff infill walls showed that traditional infills (mortar connection between frame and infill) are conceptually wrong system for the buildings in earthquake active areas. Beside heavy in-plane damage, inadequate connection between frames and infills led to the widespread out-of-plane collapse of infill walls. This has jeopardized people and escape routes during the earthquakes as well it produced significant economic loss. Many other earthqukes before showed that this is not acceptable anymore, but this one confirmed it. Therefore, this paper also proposes isolation of infill walls as a solution that can prevent such a devastating effects in future earthqaukes. Although isolation of infills is presribed in the codes it is not in use due to the fact that there are no simple and easy applicable solutions on the market. With the aim to fill this gap, a system presented here is developed. Its goal is to provide functional and easy applicable solution to the designers and construction companies and workers. Experimental tests on the full scale specimens of isolated infilled RC frames are shown, confirming the effectiveness of the isolation system. Infill walls with windows, doors and full walls are tested under various earthquake loading conditions. Furthermore, comparison with the traditional system was done, showing benefits and improvements brought by this system.The most dominant type of damage in the February 2023 Kahramanmaras earthquakes was the failure of infills walls. This paper shows just part of the effects of these earthquakes on the infills and concequences on the building inventory and people. The data was collected during the reconaissance field mission one month after the earthquake. In all cities visited damage of the infilled RC frame structures was devastating. Poor behaviour and heavy damage due to the interaction of flexible frames with the stiff infill walls showed that traditional infills (mortar connection between frame and infill) are conceptually wrong system for the buildings in earthquake active areas. Beside heavy in-plane damage, inadequate connection between frames and infills led to the widespread out-of-plane collapse of infill walls. This has jeopardized people and escape routes during the earthquakes as well it produced significant economic loss. Many other earthqukes before showed that this is not acceptable anymore, but this one confirmed it. Therefore, this paper also proposes isolation of infill walls as a solution that can prevent such a devastating effects in future earthqaukes. Although isolation of infills is presribed in the codes it is not in use due to the fact that there are no simple and easy applicable solutions on the market. With the aim to fill this gap, a system presented here is developed. Its goal is to provide functional and easy applicable solution to the designers and construction companies and workers. Experimental tests on the full scale specimens of isolated infilled RC frames are shown, confirming the effectiveness of the isolation system. Infill walls with windows, doors and full walls are tested under various earthquake loading conditions. Furthermore, comparison with the traditional system was done, showing benefits and improvements brought by this system.
Base isolation as a solution for protecting the laboratory buildings and equipment (2024)
Marinkovic, Marko ; Butenweg, Christoph
As technology of base isolation is getting more popular, it also widens the fields of its application. It is logical to apply base isolation for very important structures (hospitals, schools, theatres, etc.), but it also becomes as a good solution for safety of buildings, and also people and content inside the structures with different fields of use. In that sense, use of base isolation in research centres, laboratories and institutes becomes more common. In the north of Serbia, in Novi Sad, a state-of-the-art research building is being built for the BioSense Institute with financial support from the European Union. The part of the building with laboratories is provided with base isolation with integrated structure-borne noise insulation to protect and ensure smooth operation of the highly sensitive and capital-intensive technical installations. In addition, the decoupled laboratory module of the research building is provided with BIM-based building monitoring in order to be able to query and assess changes in the condition of the building at any time. This paper described the design and steps of installation of base isolators. Furthermore, results of on-site measurements (before, during and after construction) are presented. Sliding isolation pendulum (SIP) isolators incorporating polyurethane plate are presented as a one-package solution for both seismic and vibration isolation. Main characteristics of the system are presented. Its ease of installation and effectiveness of such a system presents big potential for the use in practice for different cases in practice (theatres, metro stations, hospitals etc.).
Obstacle encounter probability dependent local path planner for UAV operation in urban environments (2024)
Thoma, Andreas ; Gardi, Alessandro G. ; Fisher, Alex ; Braun, Carsten
Unmanned aerial vehicles (UAVs) are well-suited for various short-distance missions in urban environments. However, the path planner of such UAV is constantly challenged with the choice between avoiding obstacles horizontally or vertically. If the path planner relies on sensor information only, i.e. the path planner is a local planner, usually predefined manoeuvres or preferences are used to find a possible way. However, this method is stiff and inflexible. This work proposes a probabilistic decision-maker to set the control parameters of a classic local path planner during a flight mission. The decision-maker defines whether performing horizontal or vertical avoidance is preferable based on the probability of encountering a given number of obstacles. Here, the decision-maker considers predictions of possible future avoidance manoeuvres. It also defines an ideal flight altitude based on the probability of encountering obstacles. This work analyses the building height of all European capital cities and the probability of encountering obstacles at different altitudes to feed the decision-maker. We tested the feasibility of the proposed decision-maker with the 3DVFH*, a commonly used local path planner, in multiple simulations. The proposed probabilistic decision-maker allows the local path planner to reach the goal point significantly more often than the standard version of the 3DVFH*.
Perspectives of aminoacylases in biocatalytic synthesis of N-acyl-amino acids surfactants (2024)
Haeger, Gerrit ; Wirges, Jessika ; Bongaerts, Johannes ; Schörken, Ulrich ; Siegert, Petra
Many industrial processes are performed using harmful chemicals. The current technical synthesis of N-acyl-amino acids relies on acyl chlorides, which are typically obtained from phosgene chemistry. A greener alternative is the application of whole cells or enzymes to carry out synthesis in an environmentally friendly manner. Aminoacylases belong to the hydrolase family and the resolution of racemic mixtures of N-acetyl-amino acids is a well-known industrial process. Several new enzymes accepting long-chain fatty acids as substrates were discovered in recent years. This article reviews the synthetic potential of aminoacylases to produce biobased N-acyl-amino acid surfactants. The focus lays on a survey of the different types of aminoacylases available for synthesis and their reaction products. The enzymes are categorized according to their protein family classification and their biochemical characteristics including substrate spectra, reaction optima and process stability, both in hydrolysis and under process conditions suitable for synthesis. Finally, the benefits and future challenges of enzymatic N-acyl-amino acid synthesis with aminoacylases will be discussed.
Muscle stiffness indicating mission crew health in space (2024)
Schoenrock, Britt ; Muckelt, Paul E. ; Hastermann, Maria ; Albracht, Kirsten ; MacGregor, Robert ; Martin, David ; Gunga, Hans-Christian ; Salanova, Michele ; Stokes, Maria J. ; Warner, Martin B. ; Blottner, Dieter
Muscle function is compromised by gravitational unloading in space affecting overall musculoskeletal health. Astronauts perform daily exercise programmes to mitigate these effects but knowing which muscles to target would optimise effectiveness. Accurate inflight assessment to inform exercise programmes is critical due to lack of technologies suitable for spaceflight. Changes in mechanical properties indicate muscle health status and can be measured rapidly and non-invasively using novel technology. A hand-held MyotonPRO device enabled monitoring of muscle health for the first time in spaceflight (> 180 days). Greater/maintained stiffness indicated countermeasures were effective. Tissue stiffness was preserved in the majority of muscles (neck, shoulder, back, thigh) but Tibialis Anterior (foot lever muscle) stiffness decreased inflight vs. preflight (p < 0.0001; mean difference 149 N/m) in all 12 crewmembers. The calf muscles showed opposing effects, Gastrocnemius increasing in stiffness Soleus decreasing. Selective stiffness decrements indicate lack of preservation despite daily inflight countermeasures. This calls for more targeted exercises for lower leg muscles with vital roles as ankle joint stabilizers and in gait. Muscle stiffness is a digital biomarker for risk monitoring during future planetary explorations (Moon, Mars), for healthcare management in challenging environments or clinical disorders in people on Earth, to enable effective tailored exercise programmes.
Gastrocnemius medialis contractile behavior during running differs between simulated Lunar and Martian gravities (2021)
Richter, Charlotte ; Braunstein, Björn ; Stäudle, Benjamin ; Attias, Julia ; Süss, Alexander ; Weber, Tobias ; Mileva, Katya N. ; Rittweger, Jörn ; Green, David A. ; Albracht, Kirsten
The international partnership of space agencies has agreed to proceed forward to the Moon sustainably. Activities on the Lunar surface (0.16 g) will allow crewmembers to advance the exploration skills needed when expanding human presence to Mars (0.38 g). Whilst data from actual hypogravity activities are limited to the Apollo missions, simulation studies have indicated that ground reaction forces, mechanical work, muscle activation, and joint angles decrease with declining gravity level. However, these alterations in locomotion biomechanics do not necessarily scale to the gravity level, the reduction in gastrocnemius medialis activation even appears to level off around 0.2 g, while muscle activation pattern remains similar. Thus, it is difficult to predict whether gastrocnemius medialis contractile behavior during running on Moon will basically be the same as on Mars. Therefore, this study investigated lower limb joint kinematics and gastrocnemius medialis behavior during running at 1 g, simulated Martian gravity, and simulated Lunar gravity on the vertical treadmill facility. The results indicate that hypogravity-induced alterations in joint kinematics and contractile behavior still persist between simulated running on the Moon and Mars. This contrasts with the concept of a ceiling effect and should be carefully considered when evaluating exercise prescriptions and the transferability of locomotion practiced in Lunar gravity to Martian gravity.
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