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Ultra-Low Loading of Iron Oxide and Platinum on CVD-Graphene Composites as Effective Electrode Catalysts for Solid Acid Fuel Cells
No full textWe propose a new design for electrocatalysts consisting of two electrocatalysts (platinum and iron oxide) that are deposited on the surfaces of an oxidized graphene substrate. This design is based on a simple structure where the catalysts were deposited separately on both sides of oxidized graphene substrate; while the iron oxide precipitated out of the etching solution on the bottom-side, the surface of the oxidized graphene substrate was decorated with platinum using the atomic layer deposition technique. The Fe2O3-decorated CVD-graphene composite exhibited better hydrogen electrooxidation performance (area-normalized electrode resistance (ANR) of ~600 Ω·cm−2) and superior stability in comparison with bare-graphene samples (ANR of ~5800 Ω·cm−2). Electrochemical impedance measurements in humidified hydrogen at 240 °C for (Fe2O3|Graphene|Platinum) electrodes show ANR of ~0.06 Ω·cm−2 for a platinum loading of ~60 µgPt·cm−2 and Fe2O3 loading of ~2.4 µgFe·cm−2, resulting in an outstanding mass normalized activity of almost 280 S·mgPt−1, exceeding even state-of-the-art electrodes. This ANR value is ~30% lower than the charge transfer resistance of the same electrode composition in the absence of Fe2O3 nanoparticles. Detailed study of the Fe2O3 electrocatalytic properties reveals a significant improvement in the electrode’s activity and performance stability with the addition of iron ions to the platinum-decorated oxidized graphene cathodes, indicating that these hybrid (Fe2O3|Graphene|Platinum) materials may serve as highly efficient catalysts for solid acid fuel cells and beyond
‘Waldaj-Diskussionsclub’ Forum 2025 – Podium mit dem Präsidenten der RF –: Global Governance im Diskurs (XXV)
No full text‘Waldaj-Diskussionsclub’Forum 2025
– Podium mit dem Präsidenten der RF –
• Vorwort des Herausgebers
• Stenogramm (dt. Übers.) des Podiums im ‘Waldaj-Diskussionsclub’ (2025) am 02.10.2025 mit dem Präsidenten der Russischen Föderation. Rede – Interview – Gästefragen und Antworten von W. Putin.
• Sämtliche Textoriginale (russ.).:‘Waldaj-Diskussionsclub’ Forum 2025
– Podium mit dem Präsidenten der RF –
Global Governance im Diskurs (XXV)
● Stenogramm zum Plenum am 2. Oktober 2025 im ‘Waldaj-Diskussionsclub’. (Übersetzt a.d. Russ. von Rainer Böhme.):
○ Eröffnung der Plenarsitzung (Podium) von F. Lukjanow;
○ Podium-Rede von W. Putin;
○ Podium-Interview von F. Lukjanow mit W. Putin;
○ Gästefragen und Podium-Antworten von W. Putin.
● Textoriginale (russisch):
○ Eröffnung im ‘Waldaj-Diskussionsklub’, 02.10.2025, von F. Lukjanow;
○ Podium-Rede im ‘Waldaj-Diskussionsklub’ 2025, von W. Putin;
○ Podium-Interview ‘Waldaj-Diskussionsklub’ 2025, mit W. Putin;
○ Gästefragen u. Podium-Antworten, 02.10.2025, von W. Putin
Jüdische Geschichte(n) erzählen. Podcasting und die Herausforderungen und Chancen eines digitalen Mediums
No full textVorwort: ARCH4HEALTH – Para Sport
No full textDas ARCH4HEALTH Student Research Lab ist eine Lehrveranstaltungsreihe an der Professur für Sozial- und Gesundheitsbauten. Hierbei erarbeiten die Studierende aktuelle Fragestellungen zu einem semesterbegleitenden Thema. Sie beschäftigten sich im Sommersemester 2024 mit dem Thema „Para Sport“. Ziel der studentischen Forschungsprojekte war es den Para Sport mit seinen Herausforderungen in der Planung von Sporteinrichtungen unter der Berücksichtigung von Inklusionen und Barrierefreiheit zu untersuchen. [... aus dem Text
21st International Symposium on Electrochemical Machining Technology INSECT 2025
No full textElectrochemical technologies are known for their ability for the precise shaping of high-strength
materials on a macro and micro geometric scale with high surface quality and defined chemical-
physical surface conditions. The effective application of electrochemical and EC-based
technologies such as ECM, Wire-ECM, PECM, Laser-ECM as well as PeP requires a thorough
understanding of the specific interactions between material, process and functional properties.
In addition to traditional materials used in mechanical engineering, the machining of materials
such as hard-to-machine metals, cemented carbides, superalloys and high entropy alloys are
increasingly coming into focus. High-resolution methods for the characterization of process
mechanisms and results, as well as advanced modelling and control strategies open up new
possibilities and extend the limits of EC-based processes. By combining high efficiency and
excellent surface quality, EC-based technologies offer an outstanding potential for sustainable
and precise material and surface processing. In addition to well-established sectors such as
aerospace, medical technology and tool manufacturing, an advanced knowledge of process
design and optimization enables access to new areas of application
Fingerprint Analysis of post-processing of AM 316L using Jet-ECM
No full textLaser Powder Bed Fusion (LPBF) enables the production of complex metal components, but the
resulting surface roughness often exceeds acceptable limits, requiring post-processing.
Electrochemical methods, particularly Jet Electrochemical Machining (Jet-ECM), are promising due
to their non-mechanical nature and ability to access complex geometries. This study presents a
fingerprint analysis of Jet-ECM post-processing of LPBF-manufactured 316L stainless steel. The
influence of key process parameters–such as machining voltage, nozzle travel speed, working gap–
and process features including current density and charge transfer, is evaluated. Statistical
techniques were used to map the parameter space and examine the relationships between process
inputs and resulting surface morphology. Results show that the effects of process parameters differ
when applied to rough LPBF surfaces compared to conventionally smooth ones. Charge transfer
was identified as a particularly critical factor in achieving consistent surface modification. This
analysis provides a basis for optimizing electrochemical post-processing of AM components
Shifts from cooperative to individual-based predation defense determine microbial predator-prey dynamics
No full textPredation defense is an important feature of predator-prey interactions adding complexity to ecosystem dynamics. Prey organisms have developed various strategies to escape predation which differ in mode (elude vs. attack), reversibility (inducible vs. permanent), and scope (individual vs. cooperative defenses). While the mechanisms and controls of many singular defenses are well understood, important ecological and evolutionary facets impacting long-term predator-prey dynamics remain underexplored. This pertains especially to trade-offs and interactions between alternative defenses occurring in prey populations evolving under predation pressure. Here, we explored the dynamics of a microbial predator-prey system consisting of bacterivorous flagellates (Poteriospumella lacustris) feeding on Pseudomonas putida. Within five weeks of co-cultivation corresponding to about 35 predator generations, we observed a consistent succession of bacterial defenses in all replicates (n = 16). Initially, bacteria expressed a highly effective cooperative defense based on toxic metabolites, which brought predators close to extinction. This initial strategy, however, was consistently superseded by a second mechanism of predation defense emerging via de novo mutations. Combining experiments with mathematical modeling, we demonstrate how this succession of defenses is driven by the maximization of individual rather than population benefits, highlighting the role of rapid evolution in the breakdown of social cooperation
Private Content Discovery for P2P Data Networks
No full textThe volume of data that needs to be stored and transferred is increasing. Centralized solutions, i. e., cloud providers offer scalable storage solutions, making data availability and control dependent on a single logical entity. A self-scalable, distributed, and content-centric alternative for data exchange are peer-to-peer (P2P) data networks. P2P data networks can allow users to regain control over their data.
The content-centric approach enables users to directly request the content from the network via mostly pseudonymous identifier. Unfortunately, a query reveals interest in specific content and the source of a query can be linked to a user. The combination of source and content of a query reveals the interest of a user, enabling profiling. Furthermore, performance improvements and fail-safe mechanisms spread interests widely through the network.
In this thesis, we design and explore different protocols using privacy-enhancing mechanisms. The goal of the privacy enhancement is to improve content discovery privacy with an adjustable overhead in P2P data networks. Specifically, we focus on source and query privacy mechanisms, providing different privacy guarantees. Source privacy aims to obfuscate the source of a query. With network-level methods, we increase the number of possible sources of a query, obfuscating the source, improving source privacy. The modifications to the content discovery process aim to provide plausible deniability up to relationship anonymity for messages. The second focus, query privacy, aims to hide the item of a request. By adding probabilistic data structures and cryptographic protocols to the content discovery process, we obfuscate the item of interest in a query, increasing query privacy. Specifically, we increase the anonymity set of a query from one item to a range of items, increasing the anonymity set ideally to all existing items in the network. Private set intersection reduces the privacy impediments of the content providers. We apply, explain, and evaluate our protocols in the context of a prime example of the current P2P data networks: the InterPlanetary File System (IPFS).
The protocols are evaluated using code experiments with a simulated network, analyzing the overhead’s impact on performance. We analyze the protocols in the context of the public IPFS network by using passive measurements to evaluate the protocols’ real-world feasibility. Each proposed protocol improves the privacy of content discovery, by reducing the overall information leak, effectively limiting large-scale attacks. A combination of the underlying mechanisms with additional mechanisms like cover traffic can provide strong protection
Interesting and new street tree species for Europeancities
No full textEffects of climate change lead to decreasing vitality and increase mortality risk for many native tree speciesgrowing under harsh environmental conditions in towns and cities. Taking into account the risks of invasiveness,practical management and scientific experience alternative species and rising floristic biodiversity may help toreduce vulnerability of urban green space.Regardless of the emotional debate considering foreign species, the potential of urban street tree speciesoriginating from China may be considered for European urban places in particular in regions with expecteddrier and hotter conditions. Preselection for trees with potential high suitability for urban sites in Central Europewas done by winter hardiness zone, native range of low average precipitation sums, tree height, and sensitivityto specific urban site conditions by literature. Species meeting the restrictions were evaluated by their vitalityon 70 urban road sites. This final selection of 40 commonly used Chinese tree species took as its startingpoint observations and local experiences of three research expeditions in September 2010, 2012, and 2015concentrating on the metropole of Beijing. The results of these research expeditions confirm the potential highsuitability for the selected tree species. For the considered species practical and scientific knowledge has to beresearched for Central Europe.:1 Introduction 2
2 Methods and material 2
2.1 Study site 2
2.2 Tree species identification by literature 3
2.3 Tree species identification by field studies 4
3 Results and Discussion 5
4 Conclusions 6
Acknowledgments 6
References
Umnutzung im Fokus: Eine Übersicht an Nutzungsbausteinen für schließende Krankenhausgebäude mit dem Schwerpunkt psychiatrische Versorgung
No full textDie Arbeit untersucht die mögliche Umnutzung von Krankenhausgebäuden in Deutschland. Durch die Krankenhausreform kommt es zu Schließungen von Krankenhäusern. Parallel besteht ein Mangel an Wohnraum für Menschen mit chronisch psychischen Erkrankungen und seelischen Behinderungen.
Es wurde untersucht, welche Nutzungsbausteine für die Umnutzung von schließenden Krankenhausgebäuden in Deutschland bereits angewendet wurden und ob Nutzungsbausteine der ambulanten psychiatrischen Versorgung geeignet sind. Es wurde eine erste kategorisierte Übersicht möglicher Nutzungsbausteine mittels einer Referenzsammlung bereits umgenutzter Krankenhausgebäude erarbeitet. Es zeigte sich, dass ehemalige Krankenhausgebäude häufiger in gemischt genutzte Einrichtungen umgewandelt werden. Dabei fällt die Mehrheit der Nutzungsbausteine in die Kategorien Wohnen, Unterbringung und Betreuung sowie medizinische und gesundheitliche Versorgung.
Zur Untersuchung der ambulanten psychiatrischen Versorgung wurden Experteninterviews sowie Vorort-Analysen in Wohneinrichtungen und Sozialpsychiatrischen Diensten durchgeführt. Dabei zeigte sich eine Lücke in der Versorgungskette. Es besteht ein Wohnungsmangel für ältere Erwachsene mit psychischem und somatischem Pflegebedarf. Für die Planung der entsprechenden Wohnformen ergaben sich Schlüsselbausteine. Diese beziehen sich auf nötige Kooperationen und damit verbundene räumliche Nähe zwischen Nutzungsbausteinen der ambulanten psychiatrischen Versorgung.
Als Ergebnis der Arbeit wird die Umnutzung von Krankenhausgebäuden zu Wohnangeboten mit integrierter psychiatrischer Betreuung und ambulanter Pflege sowie medizinischen Versorgungseinrichtungen empfohlen. Dazu ergaben sich Anforderungen an die Architektur notwendiger und zusätzlicher Nutzungsbausteine. Zu den notwendigen Nutzungsbausteinen zählen vielfältige Wohnformen, Betreuung und Pflege, medizinische Versorgung und Außenbereiche. Zusätzliche Bausteine sind Friseur und Fußpflege, Cafés und Bistros, Beschäftigung und Freizeitangebote, Räume für Selbsthilfegruppen und Außenstellen des Sozialpsychiatrischen Dienstes.
Die Übersicht möglicher Nutzungsbausteine stellt eine Grundlage für zukünftige Umnutzungsprojekte dar. Die empfohlene Umnutzung kann gleichzeitig eine Lücke in der ambulanten psychiatrischen Versorgung schließen sowie die gewünschte ambulante medizinische Versorgung fördern