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Synthesis and Characterization of Composite Positive Electrode Materials for Aqueous Zinc-ion Batteries
No full textThis dissertation investigates strategies to overcome the limited cycle life of A-ZIBs with a particular focus on Copper Hexacyanoferrate (CuHCF) as a positive electrode material. The research examines the effects of thermal treatment on the chemical composition, morphology, and electrochemical performance of CuHCF. The findings indicate that optimized thermal conditions significantly influence the structure of CuHCF, leading to improved cycling stability. Additionally, after a comprehensive review of the recent relevant studies, the application of conductive polymer coatings, including polypyrrole and poly(3,4-ethylenedioxythiophene): polystyrene sulfonate to CuHCF is analyzed. These coatings act as protective layers, enhancing structural integrity, delaying the phase transition in the CuHCF lattice, and extending the cycle life. The optimal polymer concentration in the coating solutions was further studied to maximize the outcoming electrochemical performance. The research further explores the development of an innovative pouch cell design incorporating a biodegradable membrane. Transitioning from conventional flooded cell designs to the more practical pouch configurations presented challenges, particularly related to cycling stability. However, the integration of the biodegradable membrane enabled a significantly enhanced cycling stability and efficiency while aligning well with the environmental goals of A-ZIBs forgrid-scale energy storage
Influence of mechanical resonances on the linearity of adiabatic frequency conversion in whispering gallery resonators
No full text35383547Adiabatic frequency conversion enables fast and efficient tuning of laser light by coupling it into an optical resonator whose eigenfrequency is varied on a timescale shorter than its photon lifetime. In this regime, the optical frequency follows the cavity resonance, allowing frequency shifts of several hundred gigahertz within sub-microsecond time - independent of optical power and without phase-matching constraints. While a linear dependence of the cavity resonance on a control parameter (e.g., applied voltage) suggests that arbitrary temporal signals could be linearly transferred to optical frequency changes, we show that this assumption fails near mechanical resonances of the resonator. Using a millimeter-sized lithium niobate whispering gallery resonator with a pronounced mechanical mode at a center frequency of 10.5 MHz, we observe strong deviations from linearity even when higher harmonics of the control signal coincide with this resonance. The experimental results are in excellent agreement with theoretical predictions. They demonstrate that mechanical resonances impose intrinsic limits on the linearity of adiabatic frequency conversion and other frequency control schemes based on the variation of the eigenfrequency of an optical cavity.34
Intelligent data usage to combat supply bottlenecks - A data-centric solution for preventing supply bottlenecks through trusted data collaboration
No full text5964Continuous availability of medications poses a significant challenge in healthcare. When essen-tial drugs are not in stock for patients, it can lead to severe consequences for those affected. It is suggested that digitalization along the supply chain, as well as mutual information sharing, could contribute to making supply chains more transparent and efficient, improving the forecasting of potential supply shortages, and thereby directly influencing supply planning. However, there is little intrinsic motivation among supply chain participants to exchange data. Through multipart workshops and focus groups with subject matter experts, the barriers to data exchange within the supply chain have been identified, and it has been explored whether a collaborative data space with a data trustee can resolve these obstacles. In the project »HealthTrack-X«, it is evident that ensuring trust, data sovereignty, and availability from a technical standpoint can be an effective approach. This allows companies to obtain the neces-sary supply chain data to identify shortages early and take corrective actions. A data space combined with a data trustee can help overcome barriers to data sharing for companies in the healthcare sector.Eine stetige Verfügbarkeit von Arzneimitteln ist eine große Herausforderung in der Gesundheitsversorgung. Sind wichtige Medikamente für Patient:innen nicht vorrätig, kann dies zu schwerwiegenden Folgen für die Betroffenen führen. Es deutet sich an, dass eine Digitalisierung entlang der Lieferkette sowie ein gegenseitiges Bereitstellen von Informationen dazu beitragen könnten, Lieferketten transparenter und effizienter zu gestalten, die Prognose potenzieller Lieferengpässe zu verbessern und damit direkten Einfluss auf die Versorgungsplanung zu nehmen. Dennoch existiert kaum eine intrinsische Motivation bei den Lieferketten-Teilnehmenden, Daten miteinander auszutauschen. Anhand mehrteiliger Workshops und Fokusgruppen mit Fachexpert:innen wurde identifiziert, welche Hürden hinsichtlich des Datenaustausches innerhalb der Lieferkette bestehen und ob ein kollaborativer Datenraum mit einem Datentreuhänder diese Hindernisse auflösen kann. Im Projekt "HealthTrack-X" zeigt sich, dass das technische Sicherstellen von Vertrauen, Datensouveränität und -verfügbarkeit ein probates Mittel sein kann. Unternehmen erhalten dadurch die nötigen Lieferketten-Daten, um Engpässe frühzeitig erkennen und somit gegensteuern zu können. Ein Datenraum in Kombination mit einer Datentreuhand kann in der Gesundheitswirtschaft dazu führen, dass die Hürden bei Datenweitergaben für Unternehmen überwunden werden.18
Optimized multicore fiber designs for coherent combination
No full textMulticore fibers (MCFs) have already demonstrated to be a power-scalable fiber laser concept with recent demonstrations reaching the 1 kW level [1]. MCFs help getting around most of the limitations of conventional fiber laser systems by distributing the amplification load among many cores. Hereby, in most systems, a single seed beam is split up into N different sub-beams that are amplified in the cores of the MCF. After amplification, all the sub-beams are coherently combined into a single beam, which properties (average power, pulse energy, beam quality, etc) could not be reached with single core fibers [2]
Erweiterung der mehrskaligen probabilistischen Simulationskette zur durchgängigen Abbildung des Herstellprozesses und des Bauteilverhaltens auf diskontinuierlich langfaserverstärkte Kunststoffverbunde
No full textA Secure and Resilient 6G Architecture Vision of the German Flagship Project 6G-ANNA
No full text102643102660The 6th generation of wireless mobile networks is emerging as a paradigm shifting successor to unifying the experience across the physical, digital, and human worlds, pushing boundaries on performance in capacity, throughput, latency, scalability, flexibility, and reliability, while prominently addressing new major factors, including sustainability, security and privacy, as well as digital inclusion. Many research institutions and initiatives worldwide have started investigations to make 6G a reality by approximately 2030. In Germany, federal funding from the German Ministry of Education and Research (BMBF) supports a large-scale 6G initiative, with its lighthouse project, called 6G-ANNA. The core aim of this project is to develop the key aspects of a holistic, sustainable, secure, and resilient 6G system design that will simplify and improve the interaction between humans, digital assets, and the physical environment. This paper shares the vision of the project's main technical working areas and advances, spanning topics from radio access, integration of multiple networks, as well as automation and simplification in networking to new applications and testbed scenarios, including real-time digital twins and extended reality. The industrial impact and relevance of standardization makes 6G-ANNA uniquely positioned to lead and realize the vision of next-generation wireless mobile network technologies, systems, and applications.1
Effect of burnt tire-ash (water-soluble fraction) on blood and histopathological markers in Clarias gariepinus
No full text155164Aquatic habitats serve as pollutant reservoirs and experience massive pollution disasters due to anthropogenic pressure. The effect of the Water-Soluble Fraction (WSF) of burnt tire ash (BTA) was investigated on Clarias gariepinus juvenile using blood biomarkers as well as liver and gill histology. The model fish were exposed to 5 % (0.56 g/L), 10 % (1.12 g/L) and 20 % (2.24 g/L) of 96-hr LC50 (11.2 g/L) value of BTA sub-chronic doses during the experiment. Hematological indices, the liver, and gill histology were studied throughout the 28-day exposure study, which was followed by a 14-day post-exposure trial. The studies revealed that BTA-exposed fish had reduced red blood cells, packed cell volume, and hemoglobin levels with time, whereas white blood cells and leukocyte numbers increased. Concentration-dependent histopathologic abnormalities such as hyperplasia, telangiectasis, hemorrhage, desquamation, lamellar edema, and vacuolation were observed in the gill of the affected fish, in contrast to the control. Likewise, the presence of histopathologic abnormalities in the liver of BTA-exposed fish, such as vacuolar degeneration, hyperplasia, dilated portal vein, pyknotic nucleus formations, hypertrophy hepatocytes, and aggregated macrophages, was concentration-dependent. Following apparent histologic deformities that persisted in the tissues after recovery, healing from BTA exposure was only partial. C. gariepinus is an essential bioindicator of burnt tire ash's ecotoxicological impact. Point and non-point traces of burnt-tire ash to the aquatic systems may harm aquatic animal species, thus necessitating preventative actions.
The Venture Client Model and Its Challenges for Established Companies
No full textEstablished companies aim to increase their speed and innovativeness through start-up collaboration. To access start-up solutions and integrate them into their business, they are increasingly adopting the venture client model. Thereby, established companies face several challenges implementing and operating the venture client model. A challenge overview as guidelines for future research does not exist. Based on a literature review, interviews, workshops and a world café, we identify 37 challenges in seven clusters and derive three fields of action for future research and corporate practice
BCQQ: Batch-Constraint Quantum Q-Learning with Cyclic Data Re-uploading
No full textDeep reinforcement learning (DRL) often requires a large number of data and environment interactions, making the training process time-consuming. This challenge is further exacerbated in the case of batch RL, where the agent is trained solely on a pre-collected dataset without environment interactions. Recent advancements in quantum computing suggest that quantum models might require less data for training compared to classical methods. In this paper, we investigate this potential advantage by proposing a batch RL algorithm that utilizes variational quantum circuits (VQCs) as function approximators within the discrete batch-constraint deep Q-learning (BCQ) algorithm. Additionally, we introduce a novel data re-uploading scheme by cyclically shifting the order of input variables in the data encoding layers. We evaluate the efficiency of our algorithm on the OpenAI CartPole environment and compare its performance to the classical neural network-based discrete BCQ