Ingenieurwissenschaften
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- 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).
- ItemEnhanced Design and Electromagnetic Analysis of Synchronous Reluctance Machines Using Multi-Material Additive Manufacturing(New York, NY : IEEE, 2025) Akbar, Siddique; Bekele, Yitbarek Tedla; Ebrahimi, Amir; Ponick, BerndThis article comprehensively investigates the design and simulation of synchronous reluctance machines (SynRMs) using multi-material additive manufacturing (MMAM) methods. The main goal is to improve the electromagnetic performance of the machine by strategically utilizing various materials in the rotor's edge bridges to reduce quadrature inductance Lq. A comparative analysis is led on various combinations of magnetic and non-magnetic materials, examining conventionally built machines with single materials alongside additively manufactured machines with both single and multiple materials. A demonstrator machine is built to analyze and determine essential performance parameters, emphasizing the optimization of the rotor. The research establishes an optimized rotor model to enhance electromagnetic performance and examines the operational impacts on electromagnetic torque and torque oscillations. Analytical and simulation findings illustrate the capability of multi-material additive manufacturing to improve the performance of conventional electric machines.
- ItemOutstanding Platinum Recovery by Electrochemical Cathodic Leaching and Redeposition in One-Pot 2 M HCL Solution(Bristol : IOP Publishing, 2025-07-16) Sakthivel, Mariappan; Gandharva, Reshma; Schreiber, Christopher; Drillet, Jean-FrancoisSelective Pt recovery from spent Pt/C gas diffusion electrodes (GDE) is essential for sustainable proton exchange membrane fuel cell and electrolysis industry. This study presents a promising, environmentally friendly approach using pulsed electrochemical cathodic leaching (ECCL) and subsequent electrochemical cathodic deposition (ECCD) in one pot diluted HCl solution. The parameters of ECCL pulse signal were optimized by varying electrolyte concentration, cell voltage, duty cycle, pulse number, and pulse sequence. For aging of GDE, a standard accelerated degradation tests protocol was applied. The amount of dissolved Pt in the electrolyte was evaluated by UV–vis absorption peak intensity at 260 nm that is assigned to Pt (IV) chloro complex ions. A Pt dissolution rate of 99.8% from fresh and aged GDE was achieved in 2 M HCl by applying cell voltage of “only” −3 V (cathode potential: −0.55 V vs RHE) and combining long and short pulse voltage sequences. Remaining Pt in the electrode were determined from electrochemical surface area and thermogravimetric analysis profiles confirming UV–vis results. Finally, proof of concept of one-pot Pt recovery from ECCL electrolyte by means of ECCD step was demonstrated.
- ItemInvestigation of Different Pole Configurations in New Asymmetric Permanent Magnet Synchronous Reluctance Machines(New York, NY : IEEE, 2025-01-13) Ajamloo, Akbar Mohammadi; Ghaheri, Aghil; Ibrahim, Mohamed N.; Sergeant, PeterThis paper investigates the impact of pole number and configuration on key performance characteristics of a new family of asymmetric permanent magnet synchronous reluctance machines (PMSynRMs). New variants of asymmetric PMSynRMs are presented here which integrate distinct interior PM (IPM) poles and reluctance poles into a single lamination. The torque enhancement principle relies on segregating the net torque into components generated by each pole type. Torque enhancement is achieved by optimally shifting the IPM poles relative to the reluctance poles, aligning the torque peaks generated by each pole type. A comprehensive comparative analysis is conducted between the proposed asymmetric and conventional topologies, with identical PM volume, copper loss, frequency, and frame size. The analysis evaluates torque production capability, unbalanced magnetic forces, torque ripple, losses, and power factor. The results reveal that the asymmetric PMSynRMs offer improved torque, power factor, and reduced torque ripple compared to conventional designs for pole numbers 4, 6, 8, and 10. However, some asymmetric designs exhibit the drawback of unbalanced magnetic forces, which should be taken into consideration. Finally, an asymmetric PMSynRM is prototyped and tested to verify the simulation results.