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Reverse Engineering Approach for Enhancing Product Circularity Under Consideration of Ecological and Economic Aspects
No full text248264Achieving a circular economy (CE) is a key sustainability objective, but solutions and methods to guide users towards implementation at the product level are lacking. Generic guidelines such as Design for X (DfX) and purely quantitative assessment methods, such as Life Cycle Assessment (LCA), Life Cycle Costing (LCC), and circularity assessment via the Life Cycle Gap Analysis (LCGA), confront practitioners with the challenge of translating them into actionable measures. To close this gap, this study proposes a four-step reverse engineering (RE) approach that traces back circularity weaknesses along the product life cycle and derives possible changes in product design, production steps, and materials based on DfX. The approach incorporates quantitative assessment via LCA, LCGA, and LCC to ensure ecological and economic improvement based on the changes derived at product level, without burden shifting towards another life cycle phase. This approach embeds within CE frameworks, bridging qualitative and quantitative methods.4
TOPCon, TOPCoRE or TOPCon²: A simulation-Based Efficiency Analysis
No full textAs tunnel oxide passivated contact (TOPCon) cell technology has established itself as the dominant cell technology in global photovoltaic production, this study investigates com-peting architectures, including TOPCoRE (TOPCon with Rear Emitter), and local TOPCon² (passivated contacts on both sample sides), to identify paths for enhancing power output by improving the cells’ front side. The authors conduct a comprehensive simulation analysis using Quokka3, with input parameters derived from internal measurements and published data. While pointing out the necessary surface parameters to achieve a certain cell efficiency evo-lution, the sensitivity of the cell concepts to wafer quality, base resistance, and minority carrier lifetime is evaluated. The results indicate that the TOPCoRE concept on p-type wafers can be a strong contender to the standard iTOPCon, reaching 26%+ efficiency, if equally high electri-cal wafer quality can be achieved. The findings highlight the importance of further optimization paths, with local Front Surface Fields or local front TOPCon layers, demonstrating potential efficiencies of up to 26.5% and more
Robust ToA-Estimation using Convolutional Neural Networks on Randomized Channel Models
No full textMany radio-based positioning systems use time-of-arrival (ToA). We obtain it from the first and direct path of arrival (FDPoA) in a corresponding set of multipath components (MPC) of the underlying channel state information (CSI). While detection of the FDPoA under Line-of-Sight (LoS) is simple, it is prone to errors in environments with specular and diffuse reflections, as well as nonlinear diffraction, absorption, and transmission of a signal. Such Obstructed- or Non-Line-of-Sight (OLoS, NLoS) situations lead to incorrect FDPoA and consequently to incorrect ToA estimates and inaccurate positions. State-of-the-art estimators are computationally expensive and usually fail with O/NLoS at low signal-to-noise ratios (SNRs).We propose a deep learning (DL) approach to identify optimal FDPoAs as ToA directly from the raw CSI. Our 1D Convolutional Neural Network (CNN) learns the spatial distribution of MPCs of the CSI to predict correct estimates of the ToA. To train our DL model, we use QuaDRiGa to generate datasets with CIRs and ground truth ToAs for realistic 5G channel models. We found that Delay Spread (DS), k-Factor (kF), and SNR are appropriate metrics to cover most LoS-NLoS constellations in realistic datasets. We compare our DL model with state-of-the-art estimators such as threshold (PEAK), inflection point (IFP), and MUSIC and show that we consistently outperform them by about 17% for SNRs below -10 dB
Corrigendum to “Machine Learning Based Prediction of COVID-19 Mortality Suggests Repositioning of Anticancer Drug for Treating Severe Cases”[Artificial Intelligence in Life Sciences](S2667318521000209)(10.1016/j.ailsci.2021.100020)
No full textThe authors regret errors in the affiliations and acknowledgements in the original article. A: Below is a complete list will all authors and affiliations. B: Furthermore, the authors request to include the “COPERIMOplus consortium” as author and correspondingly to add a list the consortiums members in the “Acknowledgement” section of the manuscript as described on page 3. A: Here is a corrected list with all authors and affiliations. The list contains all authors and affiliations for clarity and completeness – even if no correction was applied. The “COPERIMOplus Consortium” is added as a new author at the end of the author's list. The author's order and their names are unchanged. Authors: • Thomas Lindena,b,#• Frank Hansesc,d,#• Daniel Domingo-Fernándeza• Lauren Nicole DeLonga,b• Alpha Tom Kodamullila• Jochen Schneidere• Maria J. G. T. Vehreschildf• Julia Lanznasterg• Maria Madeleine Ruethrichh• Stefan Borgmanni• Martin Howerj• Kai Willek• Torsten Feldtl• Siegbert Riegm• Bernd Hertensteinn• Christoph Wyeno• Christoph Roemmelep• Jörg Janne Vehreschildr,s,t• Carolin E. M. Jakobs,t• Melanie Stechers,t• Maria Kuzikovu• Andrea Zalianiu• Holger Fröhlicha,b• on behalf of the LEOSS study group• on behalf of the COPERIMOplus ConsortiumAuthor's Affiliations: • #equal contribution• aFraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, 53757 Sankt Augustin, Germany• bUniversity of Bonn, Bonn-Aachen International Center for IT, Friedrich Hirzebruch-Allee 6, 53115 Bonn, Germany• cEmergency Department, University Hospital Regensburg, 93053 Regensburg, Germany• dDepartment for Infectious Diseases and Infection Control, University Hospital Regensburg, Germany• eDepartment of Internal Medicine II, School of Medicine, Technical University of Munich, University Hospital rechts der Isar, 81675 Munich, Germany• fDepartment of Internal Medicine, Infectious Diseases, University Hospital Frankfurt, Goethe University Frankfurt, 60590 Frankfurt am Main, Germany• gDepartment of Internal Medicine II, Hospital Passau, Innstraße 76, 94032 Passau, Germany• hDepartment of Internal Medicine II, Hematology and Medical Oncology, University Hospital Jena, 07747 Jena, Germany• iDepartment of Infectious Diseases and Infection Control, Hospital Ingolstadt, 85049 Ingolstadt, Germany• jDepartment of Pneumology, Infectious Diseases and Intensive Care, Klinikum Dortmund gGmbH, Hospital of University Witten / Herdecke, 44137 Dortmund, Germany• kUniversity Clinic for Haematology, Oncology, Haemostaseology and Palliative Care, Johannes Wesling Medical Centre Minden, 32429 Minden, Germany• lDepartment of Gastroenterology, Hepatology and Infectious Diseases, University Hospital Düsseldorf, Medical Faculty of Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany• mDivision of Infectious Diseases, Department of Medicine II, Faculty of Medicine, Medical Center-University of Freiburg, University of Freiburg, 79106 Freiburg, Germany• nDepartment of Hematology and Oncology, Klinikum Bremen-Mitte, 28205 Bremen, Germany• oPraxis am Ebertplatz Cologne, 50668 Cologne, Germany• pInternal Medicine III - Gastroenterology and Infectious Diseases, University Hospital Augsburg, 86156 Augsburg, Germany• rDepartment II of Internal Medicine, Hematology/Oncology, Goethe University, Frankfurt, 60590 Frankfurt am Main, Germany• sDepartment I of Internal Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany• tGerman Centre for Infection Research (DZIF), partner site Bonn-Cologne, Cologne, Germany• uFraunhofer Institute for Translational Medicine and Pharmacologie (ITMP), VolksparkLabs, Schnackenburgallee 114, 22535 Hamburg, GermanyB: COPERIMOplus Consortium Member List for the “Acknowledgements” section in the manuscript The COPERIMOplus Consortium: Fraunhofer Data Protection Office (Anne Funck Hansen), Fraunhofer IAIS (Sabine, Kugler Stefan Rüping), Fraunhofer IGD (Jan Burmeister, Jörn Kohlhammer), Fraunhofer IKTS (George Sarau, Silke Christiansen), Fraunhofer IME (Oliver Keminer), Fraunhofer ITMP (Aimo Kannt, Andrea Zaliani, Ann Christina Foldenauer, Carsten Claussen, Eduard Resch, Kevin Frank), Fraunhofer MEVIS (Hendrik Laue, Horst Hahn, Jochen Hirsch, Marco Wischnewski, Matthias Günther, Saulius Archipovas), Fraunhofer SCAI (Alpha Tom Kodamullil, Andre Gemünd, Bruce Schultz, Carina Steinborn, Christian Ebeling, Daniel Domingo Fernández, Helena Hermanowski, Holger Fröhlich, Jürgen Klein, Manuel Lentzen, Marc Jacobs, Martin Hofmann-Apitius, Meike Knieps, Michael Krapp, Philipp Johannes Wendland, Philipp Wegner, Sepehr Golriz Khatami, Stephan Springstubbe, Thomas Linden), ZB MED Information Centre for Life Sciences (Juliane Fluck). The authors would like to apologise for any inconvenience caused. Thank you very much in advance for your kind assistance. DOI of original article: https://doi.org/10.1016/j.ailsci.2021.100020 Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Schloss Birlinghoven, 53757 Sankt Augustin, Germany University of Bonn, Bonn-Aachen International Center for IT, Friedrich Hirzebruch-Allee 6, 53115 Bonn, Germany
Fabrication of Sensor-Integrated Parts Using Cold Spray Additive Manufacturing
No full textCurrently used metal additive manufacturing (AM) processes are often limited regarding build rates or build volumes. Cold spray, as a comparably young AM-process, enables the production of large metal components at high deposition rates. The technology, which was developed in the mid-1980s as a coating process, accelerates particles to supersonic speeds using a De-Laval-nozzle. The particles are subsequently sprayed with high impact onto a substrate, which causes the particles to form dense layers by plastic deformation induced by their high kinetic energy. Good processability of ductile materials and manufacturability of multi-material structures thus becomes feasible. Cold spray, which can be seen as an addition to the directed energy deposition technologies, will be the focus and be linked to the insertion of sensors within this work. Possibilities and limitations, of embedding temperature sensors in AM-components during the process, are systematically developed and presented
Synergistic Strengthening Mechanism of Hybrid Nanoreinforcement and Surface Pre-Treatment in Adhesive Joining with Alumina/SiC Nanoparticles
No full text311This study investigates the combined effects of Alumina/SiC hybrid nanoreinforcements and surface pre-treatment on the mechanical strength of adhesive joints. A two-component epoxy adhesive was reinforced with 1.0 wt% Alumina/SiC nanoparticles at ratios of 10:0, 7:3, 5:5, 3:7, and 0:10 to bond aluminum alloy substrates. The adherends were pre-treated with P320 and P3000 sandpapers to generate distinct surface roughness profiles. Joint performance was strongly influenced by the interaction between nanoparticle ratio and surface roughness, reflecting the complex mechanisms governing bonding strength. To quantify these effects, Pearson correlation and heatmap analyses were employed, enabling assessment of the relationships between experimental variables and joint properties. The optimal configuration was identified as a 5:5 Alumina/SiC ratio with a surface roughness of Ra = 0.18 ± 0.01 µm, which achieved the highest bonding strength, showing a 47.0% improvement over pristine adhesive. At the same roughness, this hybrid also outperformed single-nanofiller systems, with shear strength gains of 25.7% over Alumina (10:0) and 11.8% over SiC (0:10). Pearson analyses effectively captured these trends, providing a comprehensive evaluation of variable interdependencies and quantitatively highlighting the influence of nanoparticle composition and surface pre-treatment on adhesive joint performance
Lead-free solder alloys for PV modules: Life cycle assessment for environmental impact and toxicity
No full textThis study presents a comprehensive life cycle assessment (LCA) of interconnection materials utilized in photovoltaic (PV) module manufacturing, focusing on the environmental impacts from raw material extraction to the production stage (cradle-to-gate). The primary objective is to complement the existing research of technological comparisons of different solder alloys for PV modules by ecological aspects, such as climate change, toxicity and resource use. The conducted LCA refers to the impacts of different alloys for manufacturing one state-of-the-art full-size glass-backsheet PV module, employing the Environmental Footprint 3.1 for the life cycle impact assessment method. To identify suitable (lead-free) solder materials for future high-efficiency PV modules, the analysis includes solder alloys for the interconnection of tunnel oxide passivated contact (TOPCon) as e.g. SnAgCu or SnZn and for low-temperature soldering of silicon heterojunction (SHJ) solar cells as e.g. SnBiAg or InSn. A key finding is the dominant influence of raw materials, rather than solder alloy production itself. Scarce materials like Ag, In and Ge cause high environmental impacts if used in solder alloys. The exact material composition of the alloy plays a minor role. Avoiding toxic materials such as Pb does not automatically lead to a module with improved environmental impact. To address future PV module layouts with different amounts of solder needed, the LCA is extended to various module designs, also evaluating the influence of the Cu wires. Our results complement the technological rating for interconnection materials of PV module manufacturing by environmental arguments for a sustainable product design.30
Evaluation Of Porosity In Metal Binder Jetting Due To Binder Application By Using X-ray CT
No full textMetal Binder Jetting (MBJ) offers many advantages, as the material variety also includes non-weldable materials and is capable of higher build rates compared to other powder bed-based processes, which makes the process interesting from an economical perspective. In contrast to other powder bed-based processes the binder application is unique. The aim of this work is to characterize and analyse the porosity distribution of the green parts by computed tomography. The parameters binder saturation and layer thickness are varied. These results show that binder application leads to porosity in green and sintered parts due to droplet impact. A higher binder saturation can compact the particle structure in the green part due to capillary forces. This also results in a better inter-layer bonding and leads to a lower anisotropy of the shrinkage. Resulting particle segregation in the powder bed & green part are due to powder application by a counter rotating roller
Application of Zero Overvoltage Switching in Switched Mode Power Supplies
No full textWith the increasing adoption of wide bandgap (WBG) semiconductor devices, new methods are required to manage their faster switching characteristics, particularly addressing voltage overshoots caused by fast switching. Zero Overvoltage Switching (ZOS) leverages circuit resonances during the turnoff process to nearly eliminate voltage overshoot, making fast switching essential and reducing switching losses to a minimum. This paper explores two methodologies for a novel ZOS current control in DC/DC converters: Variable Frequency Forced Continuous Conduction Mode (VF-FCCM), while efficient under specific conditions, suffers from turn-off overvoltages and significant AC losses due to high current ripple, making it unsuitable for low-load operations. In contrast, Valley Switching Discontinuous Conduction Mode (VS-DCM) mitigates overvoltage spikes and switching losses, maintaining a consistent ripple but struggles with low-load scenarios due to frequency limitations. Both methodologies were simulated and tested on a lightweight aircraft DC/DC prototype. The findings suggest VS-DCM as a promising candidate for future development
Kaskadenreaktionen für die Photobiokatalyse
No full text228233Feinchemikalien sind essenzielle Bausteine der chemischen Industrie für die Gesundheitsversorgung. Die Produktion dieser hochreinen Verbindungen ist ein komplexes Verfahren, das oft in mehrstufigen Batch-Stufen prozessiert wird. Diese Synthesen bedürfen oft langer Umrüstzeiten und besonderer Sicherheitsvorkehrungen. Damit die Chemieindustrie konkurrenzfähig bleibt, wurde eine neue Technologie entwickelt, die den kaskadierten Ablauf von Synthesestufen in einer kontinuierlich betriebenen Syntheseanlage möglich macht. Diese Kaskadenreaktionen werden für Durchflussreaktoren durch neuartige Katalysatoren realisiert, um die Vorteile einer kontinuierlichen Prozessführung, Skalierung und Heterogenisierung zu nutzen. Je nach Wunschkaskade werden Katalysatoren kombiniert auf Suprapartikeln oder Polymerfolien zur Verfügung gestellt. Anhand ausgewählter Beispiele wird die Synthese chiraler Moleküle mit dieser neuen Technologie im Forschungsfeld der photochemisch assistierten Biokatalyse gezeigt.15