KITopen
Not a member yet
63711 research outputs found
Sort by
Approaches for the Use of Rapidly Growing Willow Rods in Earth-Based Construction
No full textAbstract This chapter investigates construction applications of natural fibres and
fast-growing plant-based materials, which can be processed into load-bearing components using specially tailored digital manufacturing technology. The sourcing and
production of the developed sustainable and recyclable freeform lightweight structures based on willow and earth are described in detail and material samples are
shown. At the end-of-life, the components can be disjoined and the composite materials in the components can be fully separated mechanically for composting, recycling
or incineration. Moreover, the developed structures were prototyped, implemented
and tested in full-scale research demonstrators at the 2023 German National Garden
Show in Mannheim (BUGA23). With this contribution we show the feasibility of
such novel robotic construction methods of biogenic materials in structural applications for the first time. The envisioned application potential lies particularly in the
new construction of residential buildings, hotels, office buildings and buildings with
similar uses
Passivity-Based Stabilisation and Coordination in Networked Multi-Energy Systems
No full textThis work proposes nonlinear controllers for achieving decentralised stabilisation and distributed coordination in networked multi-energy systems comprising gas and power networks. Asymptotic stability is ensured in each case using equilibrium-independent passivity theory. This approach yields nonlinear system stability results that depend only on the properties of the components, while being topology independent and allowing arbitrary network sizes and combinations
On the consistency of pseudo-potential lattice Boltzmann methods
No full textWe derive the partial differential equation (PDE) to which the pseudo-potential lattice Boltzmann method (P-LBM) converges under diffusive scaling, providing a rigorous basis for its consistency analysis. By establishing a direct link between the method\u27s parameters and physical properties—such as phase densities, interface thickness, and surface tension—we develop a framework that enables users to specify fluid properties directly in SI units, eliminating the need for empirical parameter tuning. This allows the simulation of problems with predefined physical properties, ensuring a direct and physically meaningful parametrization. The proposed approach is implemented in OpenLB, featuring a dedicated unit converter for multiphase problems. To validate the method, we perform benchmark tests—including planar interface, static droplet, Galilean invariance, and two-phase flow between parallel plates—using R134a as the working fluid, with all properties specified in physical units. The results demonstrate that the method achieves second-order convergence to the identified PDE, confirming its numerical consistency. These findings highlight the robustness and practicality of the P-LBM, paving the way for accurate and user-friendly simulations of complex multiphase systems with well-defined physical properties
Mechanistic insights into the adverse effects of cisplatin employing the zebrafish model
No full textDer Einsatz von Cisplatin, einem weit verbreiteten Chemotherapeutikum, ist mit verschiedenen Nebenwirkungen und toxischen Reaktionen verbunden, darunter Nierentoxizität, Neurotoxizität und Ototoxizität, die seine klinische Anwendung einschränken. Eine dieser Nebenwirkungen, die Nierentoxizität, kann zu akutem Nierenversagen führen und stellt eine erhebliche Bedrohung für die Patientensicherheit dar. Das Verständnis der Mechanismen, die der cisplatininduzierten Nierentoxizität zugrunde liegen, ist entscheidend für die Entwicklung präventiver und therapeutischer Strategien zur Verringerung des Risikos einer Nierenschädigung während der klinischen Anwendung.
Um die potenziellen Regulationsmechanismen zu analysieren, wurde in dieser Studie zunächst ein Zebrafischlarvenmodell der durch Cisplatin induzierten Nephrotoxizität etabliert. Dies umfasste die Auswahl geeigneter Zeitpläne für die Injektion der Larven, die Verbesserung der Injektionstechniken und die Umsetzung von phänotypischen Scoring-Methoden. Innerhalb dieses Modells führte die funktionelle Hemmung des G-Protein-gekoppelten Östrogenrezeptors (GPER) effektiv zu einer Verringerung abnormer Phänotypen und einer Abnahme der Hochregulationeiniger Marker für Nierenschädigung, die durch Cisplatin verursacht wurden. Dies legt eine potenzielle regulierende Rolle von GPER in der durch Cisplatin induzierten Nephrotoxizität nahe. Weitere biochemische Analysen und Inhibitorexperimente zeigten, dass die Hemmung der GPER-Funktion zu einer Verringerung der Aktivierung von Mitogen-aktivierten Proteinkinasen (MAPK) führte, was darauf hindeutet, dass die GPER-MAPK-Kaskade für die durch Cisplatin induzierte Nephrotoxizität wichtig ist
Solubility, Speciation and Thermodynamics of PuCO₃OH(cr) in Carbonate Containing NaCl Solutions
No full textHigh‐Rate FA‐Based Co‐Evaporated Perovskites: Understanding Rate Limitations and Practical Considerations to Overcome Their Impact
No full textVapor phase deposition methods are readily able to achieve uniform coverage of large-area substrates and are widely considered promising for industrial-scale perovskite solar cell fabrication. However, as perovskite-silicon tandem solar cells approach commercialization, practical considerations of manufacturing throughput come into play. Here, it is shown that the inherent sublimation characteristics of the organic precursor formamidinium iodide (FAI) make increasing the deposition rate of FA-based co-evaporated perovskites negatively impact replicability and lead to a substantial decrease in power conversion efficiency (PCE). These losses are linked to reduced film homogeneity and the emergence of carbon-rich regions within the perovskite layer. To mitigate these rate-induced effects, two approaches are explored: source layout optimization and material preconditioning. Utilizing dual FAI sources rather than a single FAI source reduces the relative PCE drop from ≈23%rel to ≈9%rel at a deposition rate of ≈18 nm min−1 (14.8% PCE @ maximum power point (MPP)) compared to the baseline rate of 5 nm min−1 (16.2% PCE @MPP). Alternatively, preconditioning a single FAI source reduces the performance losses from ≈31%rel to ≈26%rel at a deposition rate of ≈21 nm min−1. These findings underscore the importance of tailored source strategies to enable high-rate FA-based co-evaporated perovskites without compromising device performance
Attack Once, Compromise All? On the Scalability of Attacks
No full textElectronic voting schemes are often criticized for being insecure, on the grounds that a successful attack would allow an adversary to manipulate all votes at once. It is argued that attacks therefore have a higher impact at lower adversary costs compared to paper-based schemes, where attacks are cumbersome. In this paper, we propose a framework to quantify how prone different protocols are to attacks that scale well. For this purpose, we introduce the notion of scalability of attacks. We give the adversary access to an oracle which can break common cryptographic building blocks and assumptions and analyze how many inputs of a (multiparty computation) protocol they can learn or manipulate for each oracle access. The more inputs are affected, the more susceptible the protocol is to attacks that scale well. We compare several pairs of protocols solving the same problem in different ways in three examples and analyze the scalability of attacks on each protocol. We find that some protocols have a fatal breakdown, i.e. all inputs are affected with only one access to the oracle, while other protocols scale linearly or have a threshold, where the number of affected inputs increases drastically from one access to the other. Our framework provides strong arguments in favoring one voting scheme over another. It enables voting authorities to compare schemes that appear equally secure at first glance, and to consider the scalability of attacks when deciding on a scheme
Screening of Six Different Potential HLRW Canister Materials Surrounded by Bentonite
No full textMost countries seeking strategies for the disposal of high-level nuclear (HLW) waste envisage the use of metallic
containers. In some deep geological repositories, the canister will be in contact with bentonite. Different types of metals
were tested so far with ambiguous results. Consistent data are available for copper and carbon steel. Different performances, however, were reported for stainless steel. In the present study six different alloys were tested: three iron-matrix alloys with different carbon contents and grain sizes, a copper-nickel alloy, zirconium, and stainless steel. They were immersed with water saturated bentonite for 10 months at 23°C under anaerobic conditions. Corrosion was assessed gravimetrically and using electron- and X-ray microscopy. Stainless steel did not show any reaction with the bentonite despite its widespread classification as disadvantageous because of its susceptibility for local corrosion at low pH and high Cl- concentrations. Many studies using stainless steel, however, were conducted with simulating bentonite pore waters but without contact with bentonite which meanwhile is known to buffer both pH and redox potential (Eh).
The promising results of the stainless-steel corrosion tests in the present study encourage further systematic investigations to improve the predictability of stainless-steel performance as HLW canister material surrounded by bentonite
Vom Rauchgas zur Ressource: moderne Verfahren zur CO2-Abscheidung im Überblick
No full textVerfahren zur Abscheidung von CO2 sind seit langem in unterschiedlichen Anwendungsfällen, z. B. in der Synthesegas-, Erdgas- und Biogas-Technik, etabliert. Intensiv erforscht, aber bislang in der industriellen Praxis nicht weit verbreitet, ist die CO2-Abscheidung aus dem Rauchgas von Verbrennungsprozessen. Diese könnte in Zukunft zur Minderung von Treibhausgasemissionen stark an Bedeutung gewinnen. Eine potenzielle Zukunftstechnologie kann zudem die Gewinnung von CO2 aus Luft sein, auch als Direct Air Capture (DAC) bezeichnet