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SSRN 2022年

作者： Brandau, Benedikt Da Silva, Adrien Brueckner, Frank Kaplan, Alexander F.H. Department of Engineering Sciences and Mathematics Luleå University of Technology Luleå97187 Sweden JENOPTIK Optical Systems GmbH System Development Advanced Manufacturing Göschwitzerstraße 25 Jena07745 Germany Fraunhofer Institute for Material and Beam Technology IWS Winterbergstraße 28 Dresden01277 Germany

Absorbance is often used for simulations or validation of process parameters for powder-based laser materials processing. In this work, the absorbance of 39 different metal powders for additive manufacturing is determined at 20 different laser wavelengths. Different grain sizes and aging states for: steels, aluminum alloys, titanium alloys, Nitinol, high entropy alloy, chromium, copper, brass and iron ore were analyzed. For this purpose, the absorbance spectrum of the powders was determined via an UV-VIS-NIR dual-beam spectrometer in the range of λ = 330 - 1560 nm. At the laser wavelengths of λ = 450 nm, 633 nm and 650 nm, the absorbance averaged over all materials was found to increase by a factor of three compared to the usual wavelength of λ = 1070 nm, with minimal variations in absorbance between materials. In the investigation of the aged or used powders, a loss of absorbance was detectable. Almost no changes from the point of view of processing aged and new AlSi10Mg powders, is expected for laser sources with λ = 450 nm. The resulting measurements provide a good basis for process parameters for a variety of laser wavelengths and materials, as well as a data set for improved absorbance simulations. © 2022, The Authors. All rights reserved.

关键词： Powder metals

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Planning method for IoT applications in logistics

Planning method for IoT applications in logistics

引用

European Conference on Smart Objects, systems and Technologies 2019, Smart SysTech 2019

作者： Poenicke, Olaf Groneberg, Maik Richter, Klaus Material Handling Engineering and Systems Fraunhofer Institute for Factory Operation and Automation IFF Magdeburg Germany

ISBN: (纸本)9783800749782

This paper discusses a method to support the planning of IoT applications in logistics processes in early planning stages. With regard to the specific characteristics and requirements of logistics processes, the method identifies feasible IoT technologies for specified use cases using a faceted classification. This developed classification is further combined with cost-benefit evaluation approaches, which are currently researched. The paper concludes with an outlook on the further development and discusses the contribution of IoT solutions to the creation of Smart Logistics Zones. © VDE VERLAG GMBH ∙ Berlin ∙ Offenbach.

关键词： Internet of things

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Formation of multiple current filaments and the effect of filament confinement in silicon based PIN diodes

Formation of multiple current filaments and the effect of fi...

引用

International Conference on Semiconductor

作者： P. Scharf C. Sohrmann Division Engineering of Adaptive Systems EAS Fraunhofer Institute for Integrated Circuits IIS Dresden Germany

ISBN: (数字)9781728110738

ISBN: (纸本)9781728110745

Electrostatic discharge (ESD) can be considered as one of the main reliability risks of modern electronic systems which causes failure of semiconductor devices by an over-current effect. One of the dominant failure mechanisms during an ESD event is thermal runaway caused by an avalanche breakdown leading to an inhomogeneous current flow and a current ***, the formation and motion of current filaments are investigated on special test structures of silicon based PIN diodes using technology computer-aided design (TCAD) simulations and transmission line pulse (TLP) measurements. In thin structures a constriction of the filament occurs as well as the formation of multiple filaments is observed.

关键词： Electrostatic discharges PIN photodiodes Semiconductor device measurement Transmission line measurements Semiconductor diodes Junctions Heating systems

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Process Simulation Using Physical Joining Models for Learning Robot-based Assembly Tasks

Process Simulation Using Physical Joining Models for Learnin...

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International Conference on Emerging Technologies and Factory Automation (ETFA)

作者： Arik Lämmle Balázs András Bálint Department of Robot and Assistive Systems Fraunhofer Institute for Manufacturing Engineering and Automation IPA Stuttgart Germany

ISBN: (数字)9781728189567

ISBN: (纸本)9781728189574

The ambitious requirements for the economical production of personalized products are one of the key drivers in the development of flexible automation solutions. Novel solution approaches for programming robots using advanced Machine Learning methods show promising results to increase flexibility. These so called intelligent automation solutions can adapt to changes in the product or manufacturing process with only minor human investment. However, the significant amounts of data needed to train the robots still limits the approach. One possible way is to generate this data is utilizing a physics simulation environment. Specialized joining models can be used to further increase the accuracy of the simulation and enrich the generated data as well as reduce the gap between the simulation and the real world. The presented work focussed on the extension of state of the art simulation environments with dedicated joining models for the assembly of electrical components in the electrical cabinet assembly. This extension is intended to make a significant contribution to Simulation-based training for intelligent robot-based automation solutions.

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Result quality evaluation of Directed Energy Deposition Additive Manufacturing simulations with progressive simplification of transient heat-source motion

引用

Procedia CIRP 2022年 111卷 277-281页

作者： M. Biegler B.A.M. Elsner I. Neubauer J. Lemke M. Rethmeier Fraunhofer Institute of Production Systems and Design Engineering (IPK) Pascalstrasse 8-9 10587 Berlin Simufact Engineering GmbH Tempowerkring 19 21079 Hamburg Germany Institut für Werkzeugmaschinen und Fabrikbetrieb IWF Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany Bundesanstalt für Materialforschung und -prüfung (BAM) Unter den Eichen 87 12205 Berlin Germany

Directed Energy Deposition (DED) additive manufacturing has recently been adopted in the industry for the build-up of structural components with weld lengths up to kilometers. As with all welding processes, DED suffers from thermal distortion, causing loss of dimensional accuracy and risk of cracking. Currently, process optimization with objective to minimize distortion requires expensive experimental trial-and-error. With numerical simulation of the DED process, this distortion compensation can be performed virtually, significantly reducing experimental trials. Although such approaches are generally available, their widespread adoption is currently being hampered by long computational times for large builds. This work presents a novel approach to reduce the calculation time by a simplification of the transient heat-source motion. This approach is assessed in terms of result accuracy for an industrial-scale component by progressively reducing the resolution of the heat-source motion. Calculation times as well as distortions in comparison to experimental trials are investigated.

关键词： DED A FEM FEA finite-element analysis calculation time computational time dimensional accuracy distortion

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Sub-Two-Cycle Carrier-Envelope-Phase-Stabilized 110W, 1.1mJ Laser

Sub-Two-Cycle Carrier-Envelope-Phase-Stabilized 110W, 1.1mJ ...

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International Conference on Ultrafast Phenomena, UP 2022

作者： Hädrich, Steffen Tschernajew, Maxim Shestaev, Evgeny Stutzki, Fabian Walther, Nico Just, Florian Karl, Florian Breitkopf, Sven Herrfurth, Oliver Seres, Imre Jójárt, Péter Várallyay, Zoltán Börzsönyi, Adám Müller, Michael Grebing, Christian Hoff, Dominik Paulus, Gerhard G. Eidam, Tino Limpert, Jens Active Fiber Systems GmbH Ernst-Ruska-Ring 17 Jena07745 Germany Institute of Applied Physics Abbe Center of Photonics Friedrich Schiller University Jena Albert-Einstein-Str. 15 Germany ELI-ALPS ELI-HU Non-Profit Ltd. Wolfgang Sandner utca 3 SzegedH-6728 Hungary Fraunhofer Institute for Applied Optics and Precision Engineering Albert-Einstein-Str. 7 Jena07745 Germany Single Cycle Instruments Hans-Knöll-Str.6 Jena07745 Germany Institute of Optics and Quantum Electronics Friedrich Schiller University Jena Max-Wien-Platz 1 Jena Germany Helmholtz-Institute Jena Fröbelstieg 3 Jena07743 Germany

We present a sub-2-cycle laser system combining high average power, pulse energy and repetition rate emitting 5.8-fs pulses with CEP-stable operation that make this system an ideal driver for next-generation attosecon... 详细信息

ISBN: (纸本)9781957171074

关键词： Pulse repetition rate

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PEM-Identification of a block-oriented nonlinear stochastic model with application to room temperature modeling

PEM-Identification of a block-oriented nonlinear stochastic ...

引用

Mediterranean Conference on Control and Automation (MED)

作者： Fabian Paschke Division Engineering of Adaptive Systems (EAS) Fraunhofer Institute for Integrated Circuits (IIS) Dresden Germany

ISBN: (数字)9781728157429

ISBN: (纸本)9781728157436

This contribution proposes a block-oriented nonlinear stochastic model, that can be identified by prediction error minimization (PEM) method. The model consists of a linear time invariant (LTI) stochastic block and a static nonlinear output feedback. Using measured data of a conference and an office room, it is demonstrated that this approach can be used for the identification of models suitable for short term room-temperature prediction.

关键词： Temperature measurement Heating systems Integrated circuit modeling Stochastic processes Predictive models Data models Cooling

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Machine Learning-Based Optimization of Chiral Photonic Nanostructures: Evolution- And Neural Network-Based Design

arXiv

引用

arXiv 2021年

作者： Mey, Oliver Rahimi-Iman, Arash Fraunhofer IIS/EAS Fraunhofer Institute for Integrated Circuits Division Engineering of Adaptive Systems Dresden Münchner Str. 16 Dresden01187 Germany Physikalisches Institut Justus-Liebig-Universität Gießen Gießen35390 Germany

Chiral photonics opens new pathways to manipulate light–matter interactions and tailor the optical response of metasurfaces and - materials by nanostructuring nontrivial patterns. Chirality of matter, such as that of molecules, and light, which in the simplest case is given by the handedness of circular polarization, have attracted much attention for applications in chemistry, nanophotonics and optical information processing. We report the design of chiral photonic structures using two machine learning methods, the evolutionary algorithm and neural network approach, for rapid and efficient optimization of optical properties for dielectric metasurfaces. The design recipes obtained for visible light in the range of transition-metal dichalcogenide exciton resonances show a frequency-dependent modification in the reflected light’s degree of circular polarization, that is represented by the difference between left- and right-circularly polarized intensity. Our results suggest the facile fabrication and characterization of optical nanopatterned reflectors for chirality-sensitive light–matter coupling scenarios employing tungsten disulfide as possible active material with features such as valley Hall effect and optical valley coherence. Copyright © 2021, The Authors. All rights reserved.

关键词： Machine learning

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Solar Light-Driven Simultaneous Pharmaceutical Pollutant Degradation and Green Hydrogen Production Using a Mesoporous Nanoscale Wo3/Bivo4 Heterostructure Photoanode

SSRN

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SSRN 2023年

作者： Davies, Katherine Rebecca Allan, Michael G. Nagarajan, Sanjay Townsend, Rachel Dunlop, Tom McGettrick, James D. Asokan, Vijay Shankar Ananthraj, Sengeni Watson, Trystan Godfrey, Ruth Durrant, James Maroto-Valer, M. Mercedes Kuehnel, Moritz F. Pitchaimuthu, Sudhagar SPECIFIC Faculty of Science and Engineering Swansea University Swansea United Kingdom Department of Chemistry Faculty of Science and Engineering Swansea University Singleton Park SwanseaSA2 8PP United Kingdom Department of Chemical Engineering University of Bath BathBA2 7AY United Kingdom Swansea University Medical School Singleton Park SwanseaSA2 8PP United Kingdom Energy and Materials Chalmers University of Technology Kemivägen 10 Gothenburg41296 Sweden Department of Applied Chemistry School of Advanced Science and Engineering Waseda University 3-4-1 Okubo Shinjuku-ku Tokyo Japan Department of Chemistry Centre for Processable Electronics Imperial College London London United Kingdom Research Centre for Carbon Solutions Institute of Mechanical Processing and Energy Engineering School of Engineering and Physical Sciences Heriot-Watt University Edinburgh United Kingdom Fraunhofer Institute for Wind Energy Systems IWES Am Haupttor 4310 Leuna06237 Germany

Photoelectrocatalysis is one of the most favourable techniques that could be used in this remit as it has the potential to utilise natural sunlight to generate oxidants in situ to mediate effective pollutant degradation. This work, therefore, utilises a mesoporous nanoscale WO3/BiVO4 heterostructure photoanode to effectively degrade ibuprofen in wastewater combined with simultaneous green hydrogen generation at the cathode under simulated sunlight. A near complete degradation (>96%) of ibuprofen (starting concentration of 100 mg/L), with no hazardous intermediates (determined via mass spectrometry analysis), along with simultaneous H2 evolution of 114 µmol/cm2 after 145 minutes was demonstrated in this work. In addition, intermediate product analysis, the role of the type of in situ oxidants on degradation, the mechanistic pathway of degradation, and the material characteristics of mesoporous photoanode were also investigated. First experimental evidence of in situ generated H2O2 contributing to the degradation of ibuprofen is presented. © 2023, The Authors. All rights reserved.

关键词： Tungsten compounds

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In situ theranostic platform uniting highly localized magnetic fluid hyperthermia, magnetic particle imaging, and thermometry in 3D

arXiv

引用

arXiv 2023年

作者： Buchholz, Oliver Sajjamark, Kulthisa Franke, Jochen Wei, Huimin Behrends, André Münkel, Christian Grüttner, Cordula Levan, Pierre von Elverfeldt, Dominik Gräser, Matthias Buzug, Thorsten Bär, Sébastien Hofmann, Ulrich G. Section for Neuroelectronic Systems Department of Neurosurgery University Medical Center Freiburg Freiburg Germany Bruker BioSpin MRI GmbH Preclinical Imaging Division Ettlingen Germany Institute of Medical Engineering University of Lübeck Lübeck23562 Germany micromod Partikeltechnologie GmbH Rostock Germany Division of Medical Physics Department of Diagnostic and Interventional Radiology University Medical Center Freiburg Freiburg Germany Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering IMTE Lübeck Germany Faculty of Medicine University of Freiburg Freiburg Germany

In all of medical profession a broad field of research is dedicated to seek less invasive and low-risk forms of therapy with the ultimate goal of non-invasive therapy, particularly in neoplasmic diseases. Theranostic platforms, combining diagnostic and therapeutic approaches within one system, have thus garnered interest to augment invasive surgical, chemical, and ionizing interventions. Magnetic particle imaging (MPI) offers, with its versatile tracer material (superparamagnetic iron oxide nanoparticles, SPION), a quite recent alternative to established radiation based diagnostic modalities. In addition, MPI lends a bimodal theranostic frame allowing to combine tomographic imaging with therapy techniques using the very same SPION. In this work, we show for the first time the interleaved combination of MPI-based imaging, therapy (highly localized magnetic fluid hyperthermia) and therapy safety control (MPI-based thermometry) within one theranostic platform in all three spatial dimensions. Copyright © 2023, The Authors. All rights reserved.

关键词： Iron oxides

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