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Low-Loss Singulation of TOPCon Half Solar Cells by TLS and Al2O3 Edge Passivation
No full textThis work addresses the separation of tunnel-oxide passivated contact (TOPCon) host solar cells into half solar cells. It demonstrates the feasibility of achieving almost loss-free cell per-formance after edge passivation by the passivated edge technology (PET). It is shown that edge passivation with aluminum oxide (Al2O3) is also compatible with TOPCon solar cells that have been fabricated with Al-free Ag screen printing paste for the front side finger contacts applying laser-enhanced contact optimization (LECO). The half solar cells, with an edge length of 182 mm x 91 mm, are separated from industrial pseudo-square M10-format TOP-Con host solar cells by thermal laser separation (TLS) from the front side. An optimized TLS process results in an efficiency loss of only slightly above 0.1%abs. A high-throughput proto-type tool with a capacity of about 16,000 half solar cells per run is used for an Al2O3 layer deposition on the cut edges. Using optimized processes, the PET recovered approximately 85%rel of the cutting losses in pseudo fill factor by applying Al2O3 edge passivation and annealing. Thus, TLS in combination with high-throughput Al2O3 edge passivation is a viable approach for industrial fabrication of highly efficient TOPCon half solar cells, whether LECO and Al-free Ag pastes are applied or not
Experimental setup for long term high-precision static friction tests for clamping systems of rotary tables in cutting machine tools
No full text241244The objective of the scientific investigation is the determination of the coefficient of static friction for clamping systems of rotary tables in cutting machine tools. New developments in this field of research are able to lead to an enhancement in tolerable cutting forces and machine accuracy or to the minimization of the required clamping forces and the constructed space too. In this context the requirement profile of the investigated clamping systems is more than complex. Since they have an immediate influence on the machine accuracy only smallest movements between the friction partners in the range of a few micrometres are tolerable. Furthermore a clamping system needs to withstand more than 100,000 clamping cycles and also braking applications in case of emergency. Against this background an experimental setup consisting of two testing benches was developed. The first testing bench offers the possibility of quick measurements of the coefficient of static friction by a linear movement to investigate a high number of different samples for a selection process. The second test bench in addition offers the possibility of testing the relevant samples by a torsional load for more than 100,000 clamping cycles and in braking applications. In a study the two test benches are validated and compared against each other based on a state of the art clamping system of a tempered steel on the basis of the determined coefficients of static friction. In addition the results of the long term friction experiments and the observed wear are discussed
Using Machine Learning to Differentiate Types of Particle Jumps in DNS Data of Sediment Transport
No full text18121821In this study, machine learning is used to identify types of jumps that share motion patterns of saltating particles in sediment transport based on DNS data. For this purpose, a framework is proposed, consisting of a partitioning of jumps and a subsequent calculation of prototypical jumps. The partitioning is achieved through cluster ensembles that aggregate the results from numerous k-means clustering models. The inputs for these models consist of large numbers of features per jump, extracted via time series analysis. As a result, four different types of jumps, associated with different stages of transport, are identified. Corresponding prototypical jumps are computed using a modified variant of dynamic time warping barycenter averaging and serve as models for the types. The framework contributes to improving the understanding of particle saltation
Spherical Iron Powder manufactured by Hydrogen Reduction for MIM and AM Application
No full textPresently, gas atomization and carbonyl process are the commercial technologies to produce spherical iron powders. Carbonyl iron powder is used for innovative solutions for a wide spectrum of different applications like diamond tools, magnetorheological fluids, materials absorbing microwaves, but mostly for Metal Injection Molding (MIM). Herewith, the high powder price has a considerable impact on the final product costs and is, therefore, a limiting fact. Coarser spherical alloy powders are applied for Additive Manufacturing (AM) with efforts being made to combine cheaper iron powders with master alloy powders to significantly reduce product costs. An alternative cost-efficient patented iron powder production technology was developed based on the hydrogen reduction of a spray dried hematite powder, which originates as a by-product of steelmakers. The production technology as well as the properties of the innovative spherical iron powder will be discussed
Expanding the HAISP Dataset: AI's Impact on Songwriting Across Two AI Song Contests
No full text2835As artificial intelligence (AI) continues to shape creative practices, understanding its role in human-AI songwriting remains crucial. This paper expands the Human-AI Song-writing Processes (HAISP) dataset by incorporating data from the 2024 AI Song Contest, building upon the original 2023 dataset. By analyzing new submissions, we provide further insights into AI’s evolving impact on songwriting workflows, creative decision-making, and control. A com-parative study of AI tool usage and participant strategies between the 2023 and 2024 contests reveals shifts in collaboration patterns and tool effectiveness. Additionally, we assess the differences between general-purpose AI systems and personalized, fine-tuned tools, highlighting their impact on creative agency. Our findings offer key design implications for AI-assisted songwriting tools, providing ac-tionable insights for AI developers and music practitioners seeking to enhance co-creative experiences
Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) is involved in the Thuringian Cluster for sustainable water research Fraunhofer IKTS ist beteiligt am Thüringer Cluster für nachhaltige Wasserforschung
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Investigation of Scalability Challenges in Advanced RF Circuits and Systems
No full textAs we stand at the border of a new technological era, RF components are becoming the core enablers of cutting-edge technologies. The most innovative products today often resemble a patchwork of complex microwave components, making it challenging to maintain, produce, and improve. To transition these systems from the lab to everyday life, scalability improvements are essential.
This dissertation explores the scalability challenges in two forefront domains: quantum computing and 6G communications. In the field of quantum computing, the focus is on improving low-noise amplifiers to transition from hybrid to fully integrated designs, using advanced technologies such as mHEMT and CMOS. In the domain of next-generation communications, the research addresses the challenges of phased-array antennas beyond 300 GHz, where tight integration is crucial for optimal performance. This work demonstrates the ways to achieve more scalable, efficient, and accessible technological solutions in these rapidly evolving fields
S1-Guideline for diagnosis and therapy of necrobiosis lipoidica
No full textNecrobiosis lipoidica (NL) is a rare granulomatous skin disease of unknown etiology that occurs frequently in association with diabetes mellitus and other comorbidities. The predilection site is the lower leg, particularly the pretibial areas. The exact pathogenesis remains unclear. Vascular disorders with microangiopathic changes and an autoimmune genesis are discussed. Necrobiosis lipoidica occurs three to six times more frequently in women. Men tend to show a more severe course and develop ulcerations more frequently. The diagnosis can often be established based on typical clinical and dermatoscopic findings. A biopsy should be performed in clinically unclear cases, in the presence of ulceration, or if there are signs of malignant transformation. Overall, the scientific data available for NL are still insufficient and there is a need for further research. However, as patients often experience a severely impaired quality of life, it is important to be aware of the limited scientific evidence and to translate it into practical therapeutic recommendations. This short version of the S1 guideline of the German Dermatological Society (DDG) summarizes the current evidence and, incorporating expert assessments, provides specific recommendations for everyday clinical practice.Online Firs
What Is a Polyolefin? A Critical Overview of Ethylene Copolymers Used as Solar Photovoltaic Module Encapsulants
No full text367395In recent years, photovoltaic (PV) encapsulant films marketed as polyolefins (POs), more specifically as PO elastomers (POEs) and thermoplastic POs (TPOs), have gained significant market share and are projected to become the dominant encapsulation films by 2030. Relative to other industries, there are significant misconceptions about the term PO in the PV industry. Both in the scientific literature as well as in sales and advertising, the terms PO, POE, and TPO are often misused to describe the same type of material with comparable properties, while in reality these may each consist of separate material classes. This paper provides a comprehensive literature and market review, to showcase a broad range of PO and other ethylene copolymer encapsulants from recent studies, and discusses the materials' properties to clarify what constitutes a "polyolefin." In addition, to promote a clearer comparison of encapsulant properties, we propose a two-dimensional taxonomy to categorize polymers used in module manufacturing, including POs. In terms of improving the reliability of solar PV modules, PO-based encapsulants have several advantages (including lower water uptake and ion diffusion), but might come with disadvantages too, such as a more complex processing and a higher sensitivity to the storage conditions and shelf life. All this might prospectively impact adhesion properties of the encapsulant to other materials' interfaces (glass, cells etc.) and end-product quality. Because the track record of field-deployed PV modules containing PO encapsulants is also limited, we hope to contribute to better material understanding and precision in communication in PV to secure quality.34