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arXiv 2023年

作者： Debastiani, Rafaela Kurpiers, Chantal Miriam Lemma, Enrico Domenico Breitung, Ben Bastmeyer, Martin Schwaiger, Ruth Gumbsch, Peter Institute of Nanotechnology Karlsruhe Institute of Technology Karlsruhe76131 Germany Eggenstein-Leopoldshafen76344 Germany Institute for Applied Materials Mechanics of Materials and Interfaces Karlsruhe Institute of Technology Eggenstein-Leopoldshafen76344 Germany Forschungszentrum Jülich Jülich52425 Germany Institute for Applied Materials - Reliability and Microstructure Karlsruhe Institute of Technology Karlsruhe76128 Germany Fraunhofer Institute for Mechanics of Materials IWM Freiburg79108 Germany Zoological Institute Karlsruhe Institute of Technology Karlsruhe76131 Germany Department of Engineering Università Campus Bio-Medico of Rome Rome00128 Italy Institute of Biological and Chemical Systems - Biological Information Processing Karlsruhe Institute of Technology Eggenstein-Leopoldshafen76344 Germany

While in situ experiments are gaining importance for the (mechanical) assessment of metamaterials or materials with complex microstructures, imaging conditions in such experiments are often challenging. The lab-based computed tomography system Xradia 810 Ultra allows for the in situ (time lapsed) mechanical testing of samples. However, the in situ loading setup from this system limits the image acquisition angle to 140°. For low contrast polymeric materials, this limited acquisition angle leads to regions of low information gain, thus preventing an accurate reconstruction of the data using a filtered back projection algorithm. Here we demonstrate how the information gain can be improved by selecting an appropriate position of the sample. A low contrast polymeric tetrahedral microlattice sample and a specifically structured sample, both scanned over 140° and 180°, demonstrate that the missing structural details in the 140° reconstruction are limited to an angular wedge of about 20°. Depending on the sample geometry and structure, applying simple strategies for the in situ experiments allows accurate reconstruction of the data. For the tetrahedral microlattice, a simple rotation of the sample by 90° provides enough X-ray absorption for an accurate reconstruction of the geometry. Copyright © 2023, The Authors. All rights reserved.

关键词： Mechanical testing

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High repetition rate high-order harmonic generation up to the carbon K-edge in an antiresonant hollow-core fiber 21

High repetition rate high-order harmonic generation up to th...

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Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XXI 2021

作者： Gebhardt, Martin Heuermann, Tobias Klas, Robert Kirsche, Alexander Liu, Chang Wang, Ziyao Lenski, Mathias Gaida, Christian Jauregui, Cesar Antonio-Lopez, Jose Schülzgen, Axel Amezcua-Correa, Rodrigo Rothhardt, Jan Limpert, Jens Institute of Applied Physics Abbe Center of Photonics Friedrich-Schiller-Universität Jena Albert-Einstein-Str. 15 Jena07745 Germany Helmholtz-Institute Jena Fröbelstieg 3 Jena07743 Germany Creol College of Optics and Photonics University of Central Florida OrlandoFL32816 United States Active Fiber Systems GmbH Ernst-Ruska-Ring 17 Jena07745 Germany Fraunhofer Institute for Applied Optics and Precision Engineering Jena Germany

ISBN: (数字)9781510641884

ISBN: (纸本)9781510641877

Intense, ultrafast laser sources with an operation wavelength beyond the well-established near-IR are valuable tools for exploiting the wavelength scaling laws of strong-field, light-matter interactions. Such laser systems enable the scaling of the phase matching photon energy cut-off in high-order harmonic generation, which allows for the generation of coherent soft X-ray radiation up to, and even beyond, the water window. Such laser-driven sources enable a plethora of subsequent applications. A number of these applications can significantly benefit from an increase in repetition rate. In that regard, ultrafast thulium-doped fiber laser systems (providing a broad amplification bandwidth in the 2 μm wavelength region) represent a promising, average-power scalable laser concept for driving high-order harmonic generation. These lasers are capable of delivering ∼100 fs pulses with multi-GW peak power at hundreds of kHz repetition rate. In this work, we show that combining ultrafast thulium-doped fiber CPA systems with HHG in an antiresonant hollow-core fiber is a promising approach to realize high photon energy cut-off HHG from a compact setup. The realization is based on combining nonlinear pulse self-compression (leading to strong-field waveforms) and phase-matched high-order harmonic generation in a single antiresonant hollow-core fiber. In this demonstration, a photon energy cut-off of approximately 330 eV has been achieved, together with a photon flux >106ph/s/eV at 300 eV. These results emphasize the great potential of exploiting the HHG wavelength scaling laws with 2 μm fiber laser technology. Improvements of the HHG efficiency, the overall HHG yield and further laser performance enhancements will be the subjects of our future work. © 2021 SPIE. All rights reserved.

关键词： Fiber lasers

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Data Marketplaces: Trends and Monetisation of Data Goods

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Intereconomics 2019年第4期54卷 208-216页

作者： Spiekermann, Markus Fraunhofer Institute for Software and Systems Engineering ISST Emil-Figge-Str. 91 Dortmund 44227 Germany

Despite the large number of academic contributions, there is no uniform definition of data ***, different data marketplaces may vary from eachother in terms of their underlying business model, type ofdata offered, functionality, market mechanisms, etc. © 2019, ZBW and Springer-Verlag GmbH Germany, part of Springer Nature.

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Fully coupled wet cylindrical turning simulation using the Finite-Pointset-Method

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Procedia CIRP 2021年 102卷 43-48页

作者： Eckart Uhlmann Enrico Barth Alexander Quellhorst Tobias Seifarth Jörg Kuhnert Kaissar Nabbout Martin Sommerfeld Technische Universität Berlin Institute for Machine Tools and Factory Management (IWF) Chair of Machine Tools and Manufacturing Technology Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Industrial Mathematics ITWM Fraunhofer-Platz 1 67663 Kaiserslautern Germany Otto von Guericke University Magdeburg Institute of Process Engineering Universitaetsplatz 2 39106 Magdeburg Germany

In industrial machining operations, many turning processes are carried out under wet conditions. In contrast, most simulation tools are only suitable for dry cutting processes due to challenges of modeling fluid-structure-interactions (FSI). In this paper, a wet, fully coupled cutting simulation using the Finite-Pointset-Method (FPM) is presented and validated for industrially relevant cylindrical turning. To facilitate the required reduction of the calculation effort, different routines like adaptive numerical discretization are applied. The results indicate different cutting fluid effects like evaporation areas around the chip.

关键词： Turning Cutting fluid Simulation

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A performance-based tabular approach for joint systematic improvement of risk control and resilience applied to telecommunication grid, gas network, and ultrasound localization system

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Environment systems and Decisions 2021年第2期41卷 286-329页

作者： Häring, Ivo Fehling-Kaschek, Mirjam Miller, Natalie Faist, Katja Ganter, Sebastian Srivastava, Kushal Jain, Aishvarya Kumar Fischer, Georg Fischer, Kai Finger, Jörg Stolz, Alexander Leismann, Tobias Hiermaier, Stefan Carli, Marco Battisti, Federica Makri, Rodoula Celozzi, Giuseppe Belesioti, Maria Sfakianakis, Evangelos Agrafioti, Evita Chalkidou, Anastasia Papadakis, George Fuggini, Clemente Bolletta, Fabio Neri, Alberto Giunta, Guiseppe Scheithauer, Hermann Höflinger, Fabian Schott, Dominik J. Schindelhauer, Christian Köhler, Sven Linkov, Igor Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institut EMI Freiburg Germany Department of Engineering Roma Tre University Rome Italy Institute of Communication and Computer Systems (ICCS) of the National Technical University of Athens Athens Greece Ericsson Telecomunicazioni S.P.A. Pagani SA Italy Hellenic Telecommunications Organization (OTE) S.A. Maroussi Athens Greece Gap Analysis Crete Greece RINA Consulting Rozzano Italy Leonardo Company Rome Italy ENI San Donato Milanese Italy Hahn-Schickard Villingen-Schwenningen Germany Department of Microsystems Engineering IMTEK University of Freiburg Freiburg Germany Computer Networks and Telematics University of Freiburg Freiburg Germany Engineering Research and Development Center US Army Corps of Engineers Concord MA United States

Organizational and technical approaches have proven successful in increasing the performance and preventing risks at socio-technical systems at all scales. Nevertheless, damaging events are often unavoidable due to a wide and dynamic threat landscape and enabled by the increasing complexity of modern systems. For overall performance and risk control at the system level, resilience can be a versatile option, in particular for reducing resources needed for system development, maintenance, reuse, or disposal. This paper presents a framework for a resilience assessment and management process that builds on existing risk management practice before, during, and after potential and real events. It leverages tabular and matrix correlation methods similar as standardized in the field of risk analysis to fulfill the step-wise resilience assessment and management for critical functions of complex systems. We present data needs for the method implementation and output generation, in particular regarding the assessment of threats and the effects of counter measures. Also included is a discussion of how the results contribute to the advancement of functional risk control and resilience enhancement at system level as well as related practical implications for its efficient implementation. The approach is applied in the domains telecommunication, gas networks, and indoor localization systems. Results and implications are further discussed. © 2021, The Author(s).

关键词： engineering of resilience ISO 31000 Joint risk and resilience analysis and management process Resilience dimensions Socio-technical system System performance function Tabular and matrix approach

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Considering characteristic profiles of technologies at the digital workplace: The influence on technostress

Considering characteristic profiles of technologies at the d...

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2020 International Conference on Information systems - Making Digital Inclusive: Blending the Local and the Global, ICIS 2020

作者： Becker, Julia Berger, Michelle Gimpel, Henner Lanzl, Julia Regal, Christian BF/M-Bayreuth Bayreuth Research Institute for Small and Medium-Sized Enterprises Bayreuth Germany FIM Research Center University of Augsburg Project Group Business and Information Systems Engineering Fraunhofer FIT Augsburg Germany

ISBN: (纸本)9781733632553

Workplaces develop more and more to digital workplaces. However, this may lead to technostress. An understanding of the profiles of technologies used at the digital workplace, their interplay, and how they influence technostress is valuable as it can assist developers of technologies and designers of workplaces to prevent technostress. Therefore, we analyze literature and conduct expert interviews to identify ten characteristics of digital technologies that relate to technostress. By analyzing data from 4,560 employees, we evaluate the characteristics. Furthermore, we develop characteristic profiles of multiple technologies used at the respondent's digital workplace. Lastly, we investigate their influence on technostress creators using structural equation modeling. We find that the different portfolios of technology profiles influence technostress creators in different manners. Our contributions are identifying additional characteristics of digital technologies, showing the importance of investigating workplaces as a whole, and highlighting design opportunities for health-oriented workplaces that alleviate technostress. © ICIS 2020. All rights reserved.

关键词： Characteristics of digital technologies Digital stress Digital technologies Digital workplace Mixed methods research Structural equation modeling Technostress

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Life Cycle Assessment of synthetic fuel production from renewable hydrogen: Process contribution and impact assessment considering different 2030 energy mixes 33

Life Cycle Assessment of synthetic fuel production from rene...

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33rd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy systems, ECOS 2020

作者： Bargiacchi, Eleonora Thonemann, Nils Geldermann, Jutta Desideri, Umberto Antonelli, Marco Department of Energy Systems Territory and Constructions Engineering University of Pisa Italy Fraunhofer Institute for Environmental Safety and Energy Technology UMSICHT Oberhausen Germany Business Administration and Production Management University of Duisburg-Essen Duisburg Germany

Renewable energy source generation has been increasing drastically for the last decades. In order to avoid grid congestions or overloads and energy curtailments, it is necessary to envisage energy storage technologies. Converting surplus electricity into hydrogen or eventually other synthetic fuels through Powerto- X technologies is regarded as a promising solution for the mid and long-term storage and for its potential of providing sector interconnection. However, synthetic fuel production consists of energy-intensive conversion steps, for which it is of importance to assess its environmental impacts before large scale plant development. This work aims at modeling and assessing the impacts of different alternative fuel synthesis based on renewable hydrogen in a life cycle assessment perspective. The analyzed fuels are chosen among the ones that can rely on a reliable and extensive infrastructure and, likewise, feed emerging and innovative technologies (e.g., fuel cells);in particular, methane, methanol, ammonia are selected as promising hydrogen carriers. The plant models developed in previous works are assessed regarding several environmental impacts in the software SimaPro. The data used in the present study included both data from ecoinvent database version 3.5, data from literature, and assumptions based on engineering practice for electricity generation, electrolysis, and concerning carbon dioxide sources. From a process contribution analysis, the sub-optimal and critical steps are pointed out and an outlook is provided. Since electricity production proved to be one of the most critical parameters, a sensitivity analysis over different 2030 energy mixes and renewable energy sources is carried out. © ECOS *** right reserved.

关键词： Life cycle

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Experimental anonymous conference key agreement using linear cluster states

arXiv

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arXiv 2022年

作者： Rückle, Lukas Budde, Jakob de Jong, Jarn Hahn, Frederik Pappa, Anna Barz, Stefanie Institute for Functional Matter and Quantum Technologies Universität Stuttgart Stuttgart70569 Germany Universität Stuttgart Stuttgart70569 Germany Electrical Engineering and Computer Science Department Technische Universität Berlin Berlin10587 Germany Dahlem Center for Complex Quantum Systems Freie Universität Berlin Berlin14195 Germany Fraunhofer-Institute for Open Communication Systems FOKUS Berlin10589 Germany

Multipartite entanglement enables secure and anonymous key exchange between multiple parties in a network. In particular Greenberger-Horne-Zeilinger (GHZ) states have been introduced as resource states for anonymous key exchange protocols, in which an anonymous subset of parties within a larger network establishes a secret key. However, the use of other types of multipartite entanglement for such protocols remains relatively unexplored. Here we demonstrate that linear cluster states can serve as a versatile and potentially scalable resource in such applications. We implemented an anonymous key exchange protocol with four photons in a linear cluster state and established a shared key between three parties in our network. We show how to optimize the protocol parameters to account for noise and to maximize the finite key rate under realistic conditions. As cluster states have been established as a flexible resource in quantum computation, we expect that our demonstration provides a first step towards their hybrid use for networked computing and communication. Copyright © 2022, The Authors. All rights reserved.

关键词： Quantum computers

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Semantic Data Management in Data Lakes

arXiv

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arXiv 2023年

作者： Hoseini, Sayed Theissen-Lipp, Johannes Quix, Christoph Department of Electrical Engineering and Computer Science Hochschule Niederrhein University of Applied Sciences Reinarzstrasse 49 NRW Krefeld47805 Germany Databases and Information Systems RWTH Aachen University Ahornstraße 55 Aachen NRW Aachen52074 Germany Department of Data Science and Artificial Intelligence Fraunhofer Institute for Applied Information Technology FIT Schloss Birlinghoven NRW St. Augustin53757 Germany

In recent years, data lakes emerged as a way to manage large amounts of heterogeneous data for modern data analytics. One way to prevent data lakes from turning into inoperable data swamps is semantic data management. Some approaches propose the linkage of metadata to knowledge graphs based on the Linked Data principles to provide more meaning and semantics to the data in the lake. Such a semantic layer may be utilized not only for data management but also to tackle the problem of data integration from heterogeneous sources, in order to make data access more expressive and interoperable. In this survey, we review recent approaches with a specific focus on the application within data lake systems and scalability to Big Data. We classify the approaches into (i) basic semantic data management, (ii) semantic modeling approaches for enriching metadata in data lakes, and (iii) methods for ontology-based data access. In each category, we cover the main techniques and their background, and compare latest research. Finally, we point out challenges for future work in this research area, which needs a closer integration of Big Data and Semantic Web technologies. © 2023, CC BY.

关键词： Big data

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Challenges and solution approaches for simulation-based reliability assessment – degradation modeling

Challenges and solution approaches for simulation-based reli...

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IEEE International Workshop Integrated Reliability

作者： André Lange Roland Jancke Division Engineering of Adaptive Systems EAS Fraunhofer Institute for Integrated Circuits IIS Dresden Germany

ISBN: (数字)9781728170589

ISBN: (纸本)9781728170596

To verify the reliability of electronic circuits and systems in automotive applications, qualification according to the industry-standards, such as AEC-QIOO, is state of the art. But will it be sufficient for future applications? Simulationbased reliability assessments in IC and system development are intended to complement qualification and allow efficient investigations of product reliability. Aging simulations for analog circuits have been available for years, but are hardly used. This article discusses degradation models as one bottleneck, outlines different requirements and approaches, and points to standards that could be a future solution.

关键词： Mathematical model Integrated circuit modeling Adaptation models Degradation Aging Reliability Transistors

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