Ingenieurwissenschaften
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- ItemThe Evolution and Future of Composite Construction in Light Aircraft(Hannover : Technische Informationsbibliothek, 2025) Wu, WilliamWithin this study the historical development, current applications and future topics of light aircraft construction shall be analyzed. It describes the evolution of used materials and construction methods starting from traditional materials such as wood and aluminum to advanced composite materials. Furthermore, the different types of composite materials and construction methods are categorized, their advantages and disadvantages are discussed. The implementation in current aircraft models by leading manufacturers such as Diamond Aircraft, Cirrus, and Elixir is presented. Further, the challenges that likely arise with the adoption of advanced composites in general aviation are discussed and finally emerging trends and technologies that may be adapted in future aircraft construction are described.
- ItemAdditively Manufactured Spoke-type Permanent Magnet Rotors: Solutions to Multidisciplinary Design Challenges and Comparison with Traditional Design(New York, NY : IEEE, 2025-10-09) Ajamloo, Akbar Mohammadi; Tiismus, Hans; Kallaste, Ants; Ibrahim, Mohamed N.; Sergeant, PeterSustainability in electrical machines demands minimizing material waste, eliminating rare-earth permanent magnets (PMs), and improving efficiency and reliability. Additive manufacturing (AM) offers a promising pathway toward these goals by enabling near-zero material waste, streamlined production, and enhanced design freedom. This study leverages the compatibility of spoke-type rotor configurations with nonrare-earth PMs and the unique advantages of AM to achieve a highly sustainable design. The paper proposes innovative solutions to address the existing challenges of using AM for developing ferrite PM rotor topologies and provides a comprehensive comparison with traditional laminated topology. A novel technique is presented, reducing torque ripple from 42% to 16%, and voltage THD from 11% to 5%. The proposed solution not only maintains the average torque but also avoids added manufacturing complexity and cost, unlike skewing techniques. Moreover, a new grooving technique is implemented, reducing the eddy current loss in the bulk rotor by more than 40%. A spoke-type design with open bridges is selected over the closed-bridge design, and a comprehensive multidisciplinary analysis is conducted. Two spoke-type rotors are 3D printed, and one traditional laminated rotor is manufactured. The experimental comparisons show that the proposed 3D printed rotors outperform the laminated design in terms of torque ripple, voltage THD, and material usage, while offering comparable power rating and back-emf.
- ItemHydrogen in General Aviation for an efficient and sustainable future(Hannover : Technische Informationsbibliothek, 2025-10-01) Wu, WilliamAs global climate change accelerates, the aviation sector faces increased urgency to reduce carbon emissions in pursuit of the global goal of Net Zero 2050. Hydrogen has emerged as a promising fuel for future green aviation, offering high energy density per unit mass and virtually zero carbon dioxide emissions. The study examines two major pathways of hydrogen implementation in general aviation: combustion in piston engines and hydrogen fuel cells. Within combustion systems, both spark-ignited and compression-ignited (by using a kerosene jet) engines are analyzed, their pros and cons. The challenges they encounter are also addressed, including premature ignition, NOx emissions, and backfiring. Hydrogen fuel cells are evaluated efficiency across varying load conditions and operating temperatures, cooling systems, and long-life spans. At the same time, major drawbacks, including weight, storage limitations, and design complexity, are also accounted for. Hydrogen use in internal combustion chambers shows a practical short-term solution as it has a high technology readiness level and requires minimal modifications to existing engines. On the contrary, Hydrogen fuel cells hold the most promising future, but are hindered by current technological barriers. The study presents a detailed comparison chart between internal combustion engines (ICE) and Hydrogen fuel cells, including efficiencies, emissions and complexity. Finally, the study concludes the importance of hydrogen in green aviation, while highlighting the need for infrastructure development and innovations in hydrogen storage.
- ItemDauborn Extraktkonzentration : Sedimentationsarme Kaffee-/ Tee- Extraktkonzentrierung : Erhöhung der Verarbeitungs- und Rohstoffeffizienz durch neue Verfahrenskette(Hannover : Technische Informationsbibliothek, 2025) Stern, Andreas; Reinhardt , Eugen; Reinhardt, Eugen; Stern, AndreasDas Dauborn Verfahren ermöglicht durch den Einsatz einer dynamischen Mikro-/Ultrafiltration direkt nach der Extraktion der Röstkaffeebohnen, eine weitgehend sedimentationsfreie Konzentrierung des Kaffee-Rohextraktes. Die Filtrierung wird kontinuierlich betrieben. Durch den Verzicht auf die Abscheidung großmolekularer Bestandteile durch einen Separator, kann diese aufwendige Technologie durch das Verfahren verdrängt werden. Neben der Senkung der Betriebskosten (Energie, Wartung und Instandhaltung) können durch das neue Verfahren die Verarbeitungsverluste wesentlich reduziert werden. Ungelöste Extraktbestandteile, die bei der Separierung als Separatorrückstände ausgetragen und entsorgt werden müssen, können durch die Verfahrenskombination im Flüssigkaffee gehalten und stabilisiert werden. Zusammen mit anderen Effekten, kann dadurch die Rohstoffausbeute und Verarbeitungseffizient des Flüssigkaffees wesentlich erhöht werden. Die vorgeschaltete dynamische Mikro-/Ultrafiltration verbessert die Standzeiten der nachfolgenden Konzentrierungsanlagen (Eindampfung oder Umkehrosmose) durch die Reduzierung von Ablagerungen. Des Weiteren werden Spül- und Reinigungsintervalle reduziert. Durch diese Effekte werden die Betriebskosten deutlich gesenkt. Beim Einsatz einer Umkehrosmose zur Extraktkonzentrierung lassen sich nach der Vorbehandlung durch eine Mikro-/Ultrafiltration, deutlich höhere Endkonzentrationen erreichen. Ein prozessintegrierter Homogenisierungsschritt stellt sicher, dass Sedimentationen im Endprodukt vermieden werden. Dies ermöglicht eine weitgehend rückstandsfreie Verarbeitung.
- ItemEnhanced findability and reusability of engineering data by contextual metadata(Cambridge : Cambridge University Press, 2023) Altun, Osman; Oladazimi, Pooya; Wawer, Max Leo; Raumel, Selina; Wurz, Marc; Barienti, Khemais; Nürnberger, Florian; Lachmayer, Roland; Mozgova, Iryna; Koepler, Oliver; Auer, SörenComplex research problems are increasingly addressed by interdisciplinary, collaborate research projects generating large amounts of heterogeneous amounts of data. The overarching processing, analysis and availability of data are critical success factors for these research efforts. Data repositories enable long term availability of such data for the scientific community. The findability and therefore reusability strongly builds on comprehensive annotations of datasets stored in repositories. Often generic metadata schema are used to annotate data. In this publication we describe the implementation of discipline specific metadata into a data repository to provide more contextual information about data. To avoid extra workload for researchers to provide such metadata a workflow with standardised data templates for automated metadata extraction during the ingest process has been developed. The enriched metadata are in the following used in the development of two repository plugins for data comparison and data visualisation. The added values of discipline-specific annotations and derived search features to support matching and reusable data is then demonstrated by use cases of two Collaborative Research Centres (CRC 1368 and CRC 1153).