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The Role of Luminescent Coupling in Monolithic Perovskite/Silicon Tandem Solar Cells
No full textLuminescent coupling (LC) is a key phenomenon in monolithic tandem solar cells. This study presents a nondestructive technique to quantitatively evaluate the LC effect, addressing a gap in the existing predictions made by optical modeling. The method involves measuring the ratio of photons emitted from the high bandgap top cell that escape through the rear, contributing additional current to the bottom cell, and to those escaping from the front side of top cell. The findings indicate that in the analyzed monolithic perovskite/silicon tandem solar cells, more than 85% of the emitted photons escaping from the perovskite top cell are used to generate additional current in the bottom cell. This process notably reduces the mismatch in the generated current between each subcell, particularly when the current is limited by the low bandgap subcell. The presented method is applicable to a variety of monolithic tandem structures, providing vital information for subcell characterization, providing vital information for predicting energy output and optimization for outdoor applications.204
Verbesserung der Messdatenqualität durch Anwendung der FAIR Guiding Principles Leveraging measurement data quality by adoption of the FAIR guiding principles
No full text441453The analysis and reuse of measured process data are enablers for sustainable and resilient manufacturing in the future. Maintaining high measurement data quality is vital for maximising the usage and value of the data at hand. To ensure this data quality, the data management must be applied consequently throughout the complete Data Life-Cycle (DLC) and adhere to the FAIR guiding principles. In the two research consortia NFDI4Ing and the Cluster of Excellence "Internet of Production,"we investigate approaches to increase the measurement of data quality by integrating the FAIR guiding principles in all data management activities of the DLC. To facilitate the uptake of the FAIR guiding principles, we underline the significance of FAIR data for the reuse of high-quality data. Second, we are introducing a harmonised DLC to streamline data management activities. Third, we concisely review current trends and best practices in FAIR-aware data management and give suggestions for implementing the FAIR guiding principles.91
Developing Adaptive Calibration and Benchmarking Methods for 6G Performance Measurement
No full textThe flexibility inherent to the 6G space through its use of virtualized/Service Based Architecture (SBA) networks means that generated performance results can be more difficult to contextualize than previous generations. In this space, experimentation, either with the purpose of evaluating the appropriate integration of a new network device, system or software or targeting the assurance of applicationdemanding performance service levels, needs to be done in such a way to ensure that the assessment is performed uninfluenced by the actual dimensioning constraints of the underlying beyond 5G (B5G)/6G experimentation platform. This paper explores the development of an Adaptive Calibration methodology, which can be used to provide context to results in the 6G space so that to ensure platform agnosticism. Exemplary results of its application in the 6G-SANDBOX project, exploiting four (4) different and geographically dispersed experimentation platforms, are presented hereby. The methodology involves the establishment of a baseline environment which can be measured before the introduction of a device/system/software under test (SUT). The results of the baseline measurement can be compared to the results including the SUT to produce deltas in multiple KPIs. These deltas can then be used to provide context to results generated within a single platform or be used to compare multiple platforms. The use of this methodology within 6G-SANDBOX uncovered significant performance disparities between the partaking platforms related to virtualization methods, and it is currently being used to drive the platforms closer to parity, investigate the virtualization issues and quantify the performance of various components within each individual platform. In this regard, the application of the proposed methodology is proven substantial to increase confidence in the SUT assessment results performed over B5G/6G experimentation platforms
Effect of TiCN Reinforcement on the Tensile Properties of Nickel Manufactured by Laser Powder Bed Fusion
No full text11501157Pure nickel (Ni) is known for its low mechanical properties which limits its range of applications. This study explored the possibility of improving the tensile properties of Ni with the addition of titanium carbonitride (TiCN) reinforcement using laser powder bed fusion. Horizontally built tensile specimens of 100wt% Ni and Ni-10wt%TiCN were tested according to ASTM E8/E8M-21. The Ni-10wt%TiCN samples had an ultimate tensile strength (UTS) of 751.65 MPa, yield strength (YS) of 550.30 MPa and elongation (EL) of 11.08 %. Compared to pure Ni, this represents an increase of 112 % in UTS and 79 % in YS respectively, with a reduction of only 4 % in EL. The findings demonstrate that the TiCN reinforcement enhanced the tensile properties of Ni while retaining desirable ductility. Thus, there is potential for application of this composite material where currently duranickel is used, for example spring contacts
Multi-scale microstructure and its synergetic strengthening effect in stress rupture life of Inconel 718 fabricated by high-deposition-rate laser directed energy deposition
No full textSuperior elevated temperature properties are critical for the application of Inconel 718 in hot-end components. The utilization of high-deposition-rate laser directed energy deposition (HDR-LDED) increases the microstructural diversity of Inconel 718, which accordingly provides more opportunities for properties improvement. Herein, Inconel 718 alloy with a multi-scale microstructure were fabricated by HDR-LDED followed by customized heat treatment. The coarser columnar grains (width ∼300 μm) were obtained with γ" phase (diameter ∼33.74 nm and volume fraction ∼15.16 %) distributed homogeneously in the grain and the fine Laves phases (length ∼3.69 μm; width ∼1.94 μm; aspect ratio ∼1.99 and volume fraction ∼1.55 %) in the inter-dendritic region. This multi-scale microstructure possesses an excellent stress rupture life of 342.9 h with the elongation of 13 % at 650 °C, which far exceeds that of the forging (106 h, 4.2 %), It is attributed to the reduced number of transverse grain boundaries, the finer Laves phase accommodating many dislocations, and γ" phase promoting the formation of stacking faults, Lomer-Cottrell locks and nanotwins. The findings demonstrate the great potential of additively manufactured microstructure in properties enhancement, and may be enlightening for the development of novel customized high-temperature alloys.91
Unifying work values
No full textThis paper addresses challenges in personal work value research, particularly the lack of theoretical and explanatory foundations. With a focus on lists of constructs and potential biases and blind spots in past work value conceptualizations, the diversity of instruments used to assess values in organizational settings has led to ambiguity and incomplete progress in the field. By integrating propositions from basic value research, this paper develops a comprehensive work value theory. The theory is based on the compatibility and conflict of underlying basic motivational goals in work contexts, as postulated by the theory of basic human values. We review past instruments from work value research to consider a broad range of constructs with the purpose of refining broader work value constructs and enhance their theoretical capabilities in organizational settings. To achieve that, we resolve definitional inconsistencies, enable a context-sensitive theorizing of values in a motivational circumplex and broaden the scope of work value constructs to cover personal and social-focused dimensions. The latter is discussed considering the fantasmatic logic of neoliberal ideology. The developed theoretical framework can guide future research on the role of work values for organizational behavior and organizational performance, as well as on the role of fit between personal and organizational values. The paper concludes by highlighting the need to empirically validate the proposed work value model across different cultures and organizational contexts.1
Inline-Monitoring zur Prozesskettenverkürzung bei der spanenden Bearbeitung von CFK-Flugzeugstrukturen
No full textDie vorliegende Arbeit befasst sich mit der Zukunft der prozessparallelen Qualitätssicherung bei der spanenden Bearbeitung von CFK-Bauteilen der Luftfahrtindustrie. Im Fokus steht die Entwicklung eines innovativen Inline-Monitorings und der erforderlichen sensorgestützten Teilsysteme, die eine automatisierte Bewertung der Oberflächen-, Kontur- und Prozessgüte unmittelbar nach der Bearbeitung bieten.
Unter Einsatz einer Infrarotkamera wird die durch den Fräsprozess in das Bauteil eingeleitete Wärme zur Identifikation und Bewertung der Oberflächengüte genutzt. Zur prozessparallelen Bewertung des Werkzeugverschleißes wird ein sensorischer Werkzeughalter eingesetzt, sodass Werkzeuge bis zum realen Standzeitende genutzt und gleichzeitig die Prozesssicherheit gewährleistet werden. Das Tracking der Maschinenbewegung wird untersucht, um Rückschlüsse auf die Konturgüte der resultierenden Bauteile zu ziehen. Es wird eine Systemarchitektur konzipiert, die die Teilsysteme über das Kommunikationsframework OPC-UA verknüpft und synchronisiert.
Die Forschungsstudie integriert die Ansätze der Industrie 4.0 in die prozessparallele Qualitätssicherung und schafft ein modulares Gesamtsystem, das die individuelle Verwertung der Teilsysteme sicherstellt
Casting of complex open cellular structures using high manganese steel
No full textHigh manganese steels offer an excellent combination of high strength and good ductility, making them ideal for lightweight and energy absorbing applications such as open cellular structures. Additive manufacturing is often used to produce metallic open cellular structures since it allows a high complexity of the geometry and high material efficiency, but the structures often exhibit anisotropic behavior and processing requires specific powder sizes with correspondingly high prices. This study therefore addresses the feasibility of investment casting to produce open cellular structures. A high manganese X30Mn22 base alloy with different contents of aluminum (0, 1 and 5 wt %) was used for the manufacturing of a newly designed cell structure. Processing parameters and mold materials needed to be adjusted due to pronounced chemical reactions with the commercial SiO2-based mold material. Using an Al2O3-based mold material and increasing the mold temperature during casting to 1000 °C allowed for the successful casting of high manganese steel structures with different designs regarding the strut diameter. Quasi-static compression tests of the structures confirm the cast quality and illustrate the effect of increasing alloying contents of Al on the deformation behavior, building the foundation for the development of programmable cellular structures for energy absorbing applications.3
Integration of Microwave SMD Components into Organic Multilayer PCBs
No full textThe need to integrate high-frequency electronic components into high-reliability, low-cost packages is continuously increasing. The ability to achieve high-performance miniaturized system-in-package solutions by integrating commercially available components into the printed circuit boards (PCBs) build-up allows a high flexibility with rapid system upgrade cycles and ensures resilience against component obsolescence or temporary unavailability. This article details the integration of a commercial surface mount device (SMD) S-band Low Noise Amplifier (LNA) and its SMD passive bias network into a low-cost PCB packages employing the use of standard materials in an innovative manufacturing process. In particular, the article describes the selection of materials, the layout design and the manufacturing process phases of a proof of concept (POC) package. We describe the details of the build-up of the POC package focusing on two fundamental aspects of the manufacturing process: the use of modified solder mask in the build-up and the stack of pre-cut pre-pregs adapted to the embedded components. The POC was realized with Megtron-7 (Panasonic) in a symmetric construction and connections between RF and DC copper routing layers are done through μ -vias. An automated industrial process was used for component picking, placing, and soldering. Profilometer measurements of the surface topography allowed the determination of the number and sequences of cut-outs of the prepregs used for the SMD components embedding. The fabricated packages, show good reproducibility, demon-strating the industrial-level applicability of the technological process, especially in scenarios demanding high module density and high integration
SYSTEMATIC REVIEW ON FAST FREQUENCY ANCILLARY SERVICES PROVIDED BY LARGE-SCALE HYDROGEN ELECTROLYZER PLANTS
No full text341348The decrease in physical inertia within AC grids may lead to more serious frequency deviations caused by power imbalances. To address these challenges attention has been paid to the potential of converter-connected resources to reduce frequency deviations. Since grid development plans aim to integrate a large capacity of hydrogen electrolyzer plants (HE) into the power grid, the analysis should be extended to include the ability of these loads to reduce frequency deviations. This paper performs a systematic review to evaluate the state-of-research on the potential of large-scale HE to reduce the rate-of-change-of-frequency and maximum frequency deviation. Current literature states a high potential of HE to counteract frequency deviation. Furthermore, various control approaches for delivering frequency ancillary services have been investigated. However, the paper identifies a research gap concerning applicability of the control approaches to large-scale HE considering resulting fluctuation in the flow rate of hydrogen production