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Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

Chinese Journal of Mechanical Engineering 2024年第3期37卷 297-310页

作者： Chuang Liu Dongzhi Sun Xianfeng Zhang Florence Andrieux Tobias Gersterc School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China fraunhofer institute for Mechanics of Materials(IWM) 79108 FreiburgGermany fraunhofer institute for High Speed Dynamics Ernst-Mach-Institute(EMI)79104 FreiburgGermany

Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive *** study the mechanical behavior of a typical ductile cast iron(GJS-450)with nodular graphite,uni-axial quasi-static and dynamic tensile tests at strain rates of 10^(-4),1,10,100,and 250 s^(-1)were carried *** order to investigate the influence of stress state on the deformation and fracture parameters,specimens with various geometries were used in the *** strain curves and fracture strains of the GJS-450 alloy in the strain rate range of 10^(-4)to 250 s^(-1)were obtained.A strain rate-dependent plastic flow model was proposed to describe the mechanical behavior in the corresponding strain-rate *** available damage model was extended to take the strain rate into account and calibrated based on the analysis of local fracture *** with the proposed plastic flow model and the damage model were conducted to observe the deformation and fracture *** results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 *** predictions with the proposed plastic flow and damage models at various strain rates agree well with the experimental results,which illustrates that the rate-dependent plastic flow and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain *** proposed plastic flow and damage models can be used to describe the deformation and fracture analysis of materials with similar properties.

关键词： Dynamic behavior of materials Strain rate dependency Damage model Voce model Cast iron

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Experimental and numerical investigation on alternatives to sandy gravel

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Defence Technology（防务技术） 2024年第1期31卷 130-141页

作者： V.Denefeld H.Aurich fraunhofer institute for High-Speed Dynamics Ernst-Mach-Institut(EMI)Ernst-Zermelo-Str.479104FreiburgGermany fraunhofer institute for High-Speed Dynamics Ernst-Mach-Institut(EMI)Am Christianswuhr 279400KandernGermany

The NATO agreement STANAG 4569 defines the protection levels for the occupants of logistic and light armored *** Allied Engineering Publication,AEP-55,Volume 2 document outlines the test conditions for underbelly improvised explosive device(IEDs),which must be buried in water-saturated sandy *** use of sandy gravel has some drawbacks,for instance reproducibility,time consumption,and *** paper focuses on the investigation of four alternatives to sandy gravel,which could produce similar specific and cumulative impulses:a concrete pot filled with water,a concrete pot filled with quartz sand,a steel pot without filling and a concrete pot filled with glass spheres(diameter 200μm—300μm)and different water *** impulses are measured with a ring technology developed at the fraunhofer EMI.A numerical soil model based on the work of Marrs,2014 and Fi serov a,2006 and considering the soil moisture was used to simulate the experiments with glass spheres at different water contents,showing much better agreement with the experiments than the classical Laine&Sandvik model,even for high saturation *** results can be used to create new test conditions at original scale that are more cost-effective,more reproducible and simpler to manage in comparison to the current tests carried out with STANAG sandy gravel.

关键词： Improvised explosive device(IED) Specific impulse Momentum transfer Sandy gravel Glass spheres Numerical model Soil moisture

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Pressurized environments directly influence friction and wear of dry steel contacts—Investigations in a novel high fluid pressure tribometer

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Friction 2024年第7期12卷 1599-1617页

作者： Paul REICHLE Jakob BARZ Georg UMLAUF Günter E.M.TOVAR institute of Interfacial Process Engineering and Plasma Technology(IGVP) University of StuttgartStuttgart 70569Germany fraunhofer institute for Interfacial Engineering and Biotechnology(IGB) Stuttgart 70569Germany

To reduce the usage of classical lubricants in deep drawing,a new tribological system based on volatile lubricants was ***,a volatile medium is injected under high pressure into the interstice between drawing tool and sheet *** on temperature and pressure,the temporary lubricant may exist in its gaseous or liquid *** this study,a novel high fluid pressure tribometer was designed to investigate the friction and wear of dry steel contacts under comparable conditions like in dry deep ***,a new ball-on-disc tribometer was designed and integrated into a high-pressure *** specifically investigate the effects of different environments(technical air,liquid and gaseous carbon dioxide,nitrogen,argon)at atmospheric and high pressure(0.1 MPa,6 MPa)on tribology,the specimens and all components were operating *** the experiments,the friction was measured *** show that the highest friction occurs in air and the lowest in carbon dioxide *** to the experiments,the wear of the specimens was assessed along with changes in surface chemistry related to tribochemical ***,the tribology of the dry sliding contacts is correlated to changes of the surface *** differences as well as similarities regarding the different fluid environments are *** the results show,the differences between the media used are most pronounced at elevated ***,this work gives clear indications on the suitability of volatile lubricants in dry friction or rather gas lubrication,especially for dry deep drawing.

关键词： dry friction and dry wear gas lubrication carbon dioxide tribo-layer dry metal forming

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Methodology for the assessment of the friction torque of ball slewing bearings considering preload scatter

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Friction 2024年第8期12卷 1838-1857页

作者： Iñigo ESCANCIANO Iker HERAS Florian SCHLEICH Josu AGUIRREBEITIA Department of Mechanical Engineering University of the Basque CountryBilbao 48080Spain fraunhofer-institute for Wind Energy Systems IWES Hamburg 27572Germany

This manuscript presents an innovative methodology for the assessment of the friction torque of ball slewing *** methodology aims to overcome the limitations of state-of-the-art approaches,especially when the friction torque is conditioned by the preload of the *** this end,the authors propose to simulate the preload scatter when solving the load distribution problem,prior to the friction torque *** preload scatter allows to simulate a progressive transition of the balls from a four-point contact state to a two-point contact *** implementing this capability into an analytical model,the authors achieve a successful correlation with experimental ***,depending on the stiffness of the structures to which the bearing is assembled,it is demonstrated that the rigid ring assumption can lead to inaccurate friction torque results when a tilting moment is *** methodology described in this research work is meant to have a practical ***,the manuscript provides guidelines about how to use and tune the analytical model to get a reliable friction torque prediction tool.

关键词： slewing bearing ball bearing friction torque preload scatter

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Fatty acids derived from oviposition systems guide female black soldier flies(Hermetia illucens)toward egg deposition sites

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Insect Science 2024年第4期31卷 1231-1248页

作者： Patrick Klüber Emna Arous Jeanny Jerschow Marco Fraatz Daniel Bakonyi Martin Rühl Holger Zorn Department Bioresources Fraunhofer Institute for Molecular Biology and Applied EcologyGiessenGermany institute of Food Chemistry and Food Biotechnology Justus Liebig University GiessenGiessenGermany

The black soldier fly,Hermetia illucens,comes with big promises for industrial purposes since its larvae feed polyphagously on a broad spectrum of organic ***,research focusing on adult flies is scarce,which is inconsistent with their reproductive relevance within the rearing *** particular,directed oviposition is a challenge in artificial ***,decomposing organic matter is commonly used as oviposition substrate,which has extensive potential for improvement in view of the lack of standardization and the risk of microbial ***,we identified three fatty acids and one fatty acid methyl ester derived from the surface of old oviposition sites and targeted to elucidate their effect on preference behavior and oviposition site selection using Y-olfactometry and prepared oviposition sites,*** to tetradecanoic acid attracted gravid females and stimulated oviposition most strongly,while decanoic acid demonstrated a repulsive *** kept in mixed-sex populations were attracted by tetradecanoic acid,resulting in a higher egg mass found in the compound box(3.0–11.4 fold),a≥2.3 fold reduction of nonspecifically deposited eggs,and the highest total egg ***,decanoic and dodecanoic acid caused females to lay a greater proportion of eggs nonspecifically outside both *** data suggest that fatty acids,especially tetradecanoic acid,are important cues for oviposition site selection in black soldier *** order to achieve a directed oviposition behavior,the role of further short-and long-chain fatty acids as attractants should be examined.

关键词： black soldier fly Hermetia illucens fatty acids insects as food and feed oviposition oviposition site selection tetradecanoic acid

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Energy Disaggregation of Industrial Machinery Utilizing Artificial Neural Networks for Non-intrusive Load Monitoring

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Energy and AI 2024年第3期17卷 342-356页

作者： Philipp Pelger Johannes Steinleitner Alexander Sauer fraunhofer institute for Manufacturing Engineering and Automation IPA Stuttgart 70569Germany institute for Energy Efficiency in Production(EEP) University of StuttgartStuttgart 70569Germany

This paper explores the application of non-intrusive load monitoring techniques in the industrial sector for disaggregating the energy consumption of machinery in manufacturing processes. With an increasing focus on energy efficiency and decarbonization measures, achieving energy transparency in production becomes crucial. Utilizing non-intrusive load monitoring, energy data analysis and processing can provide valuable insights for informed decision-making on energy efficiency improvements and emission reductions. While non-intrusive load monitoring has been extensively researched in the building and residential sectors, the application in the industrial manufacturing domain needs to be further explored. This paper addresses this research gap by adapting established non-intrusive load monitoring techniques to an industrial dataset. By employing artificial neural networks for energy disaggregation, the determination of energy consumption of industrial machinery is made possible. Therefore, a generally applicable cross-energy carrier method to disaggregate the energy consumption of machinery in manufacturing processes is developed using a design science research approach and validated through a practical case study utilizing a compressed air demonstrator. The results show that the utilization of artificial neural networks is well-suited for energy disaggregation of industrial data, effectively identifying on and off states, multi-level states and continuously variable states. Non-intrusive load monitoring should be further considered in the research of emerging artificial intelligence technologies in energy consumption evaluation. It can be a viable alternative for intrusive load monitoring and is a prerequisite to installing energy meters for every machine.

关键词： Non-intrusive load monitoring Energy transparency Energy consumption evaluation Industrial manufacturing Artificial neural networks

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Deep learning-based prediction of 3-dimensional silver contact shapes enabling improved quality control in solar cell metallization

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Energy and AI 2024年第3期17卷 513-524页

作者： Marius Singler Akshay Patil Linda Ney Andreas Lorenz Sebastian Tepner Florian Clement fraunhofer institute for Solar Energy Systems(ISE) Heidenhofstr.279110 FreiburgGermany EKRA Automatisierungstechnik GmbH Zeppelinstraße 1674357 BonnigheimGermany

The industrial metallization of Si solar cells predominantly relies on screen printing,with silver as the preferred electrode ***,the design of commercial screens often leads to suboptimal silver usage and increased electrical resistance due to print-related inhomogeneities like mesh marks,constrictions and ***-time monitoring of quality parameters during production has thus become increasingly *** inline optical quality control systems usually only include 2D visualizations of the printed layout,which limits their effectiveness in quality *** that allow 3D measurements are usually slow,expensive,and therefore not worth considering in most *** research focuses on the development of a model that can estimate the three-dimensional shape of printed contact fingers from a single 2D image without the need of additional hardware using deep ***,a workflow for the generation of training data,which involves the creation of image pairs from a 2D microscope and a 3D confocal laser scanning microscope(CLSM)to accurately represent solar cell fingers,is *** model training,the predicted height maps are compared with the ground truth height maps,and the robustness of the model with respect to a paste variation and screen parameter variation is *** results confirm the feasibility and reliability of deep learning-based 3D shape estimation,extending its applicability to new,previously unseen data from screen-printed contact *** a structural similarity index(SSIM)score of 0.76,a strong correlation between the estimated and ground truth height maps is *** summary,our deep learning-based approach for height map estimation offers an effective and reliable solution for fast inline detection and analysis of the cross-sectional area of the printed contact fingers.

关键词： Deep Learning Front-side metallization Image2Heigth Solar cell Screen-printing

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Promoting the production of challenging proteins via induced expression in CHO cells and modified cell-free lysates harboring T7 RNA polymerase and mutant eIF2α

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Synthetic and Systems Biotechnology 2024年第3期9卷 416-424页

作者： Jeffrey L.Schloßhauer Lena Tholen Alexander Korner Stefan Kubick Sofia Chatzopoulou Anja Honow Anne Zemella fraunhofer Project Group PZ-Syn of the fraunhofer institute for Cell Therapy and Immunology-IZI Branch Bioanalytics and Bioprocesses-IZI-BBAm MühlenbergPotsdamGermany fraunhofer institute for Cell Therapy and Immunology-IZI Branch Bioanalytics and Bioprocesses-IZI-BBAm MühlenbergPotsdamGermany Faculty of Health Sciences Joint Faculty of the Brandenburg University of Technology Cottbus-SenftenbergThe Brandenburg Medical School Theodor FontaneUniversity of PotsdamPotsdamGermany institute for Chemistry and Biochemistry Laboratory of Protein BiochemistryFreie Universitat BerlinThielallee 6314195BerlinGermany institute of Biotechnology Technische Universit¨at BerlinStraße des 17.Juni 13510623BerlinGermany New/era/mabs GmbH August-Bebel-Str.8914482PotsdamGermany

Chinese hamster ovary(CHO)cells are crucial in biopharmaceutical production due to their scalability and capacity for human-like post-translational ***,toxic proteins and membrane proteins are often difficult-to-express in living ***,cell-free protein synthesis can be *** study explores innovative strategies for enhancing the production of challenging proteins through the modification of CHO cells by investigating both,cell-based and cell-free approaches.A major result in our study involves the integration of a mutant eIF2 translation initiation factor and T7 RNA polymerase into CHO cell lysates for cell-free protein *** resulted in elevated yields,while eliminating the necessity for exogenous additions during cell-free production,thereby substantially enhancing ***,we explore the potential of the Rosa26 genomic site for the integration of T7 RNA polymerase and cell-based tetracycline-controlled protein *** findings provide promising advancements in bioproduction technologies,offering flexibility to switch between cell-free and cell-based protein production as needed.

关键词： Inducible expression CHO cells Cell-free protein synthesis CRISPR T7 RNA polymerase eIF2 Rosa26

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Gene complementation analysis indicates that parasitic dodder plants do not depend on the host FT protein for flowering

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Plant Communications 2024年第5期5卷 104-108页

作者： Sina Mackelmann Andrea Kanel Lara M.Kosters Peter Lyko Dirk Prufer Gundula A.Noll Susann Wicke institute of Plant Biology and Biotechnology University of MuensterSchlossplatz 848143 MuensterGermany institute for Biology Humboldt-University of BerlinHaus 22Philippstr.1310115 BerlinGermany fraunhofer institute for Molecular Biology and Applied Ecology IME Schlossplatz 848143 MuensterGermany

Dear Editor,Cuscuta,a genus of parasitic plants,poses a significant threat to global agriculture due to its broad host range that encompasses numerous cultivated *** plants form specialized feeding organs(haustoria)that connect to the host vascular tissue and import water,nutrients,secondary metabolites,small RNAs,mRNAs,and *** such protein is FT,a peptide hormone and florigen that was recently proposed to cause the synchronization of flowering in the parasite–host system(Shen et al.,2020).

关键词： specialized organs analysis

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Wear-resistant CoCrNi multi-principal element alloy at cryogenic temperature

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Science Bulletin 2024年第2期69卷 227-236页

作者： Yue Ren Qing Zhou Dongpeng Hua Zhuobin Huang Yulong Li Qian Jia Peter Gumbsch Christian Greiner Haifeng Wang Weimin Liu State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China institute for Applied Materials Karlsruhe Institute of TechnologyKarlsruhe 76131Germany IAM-ZM MicroTribology CenterμTC Karlsruhe Institute of TechnologyKarlsruhe 76131Germany fraunhofer IWM Freiburg 79108Germany State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Traditional high strength engineering alloys suffer from serious surface brittleness and inferior wear performance when servicing under sliding contact at cryogenic ***,we report that the recently emerging CoCrNi multi-principal element alloy defies this trend and presents dramatically enhanced wear resistance when temperature decreases from 273 to 153 K,surpassing those of cryogenic austenitic *** temperature-dependent structure characteristics and deformation mechanisms influencing the cryogenic wear resistance of CoCrNi are clarified through microscopic observation and atomistic *** is found that sliding-induced subsurface structures show distinct scenarios at different deformation *** cryogenic condition,significant grain refinement and a deep plastic zone give rise to an extended microstructural gradient below the surface,which can accommodate massive sliding deformation,in direct contrast to the strain localization and delamination at 273 ***,the temperature-dependent cryogenic deformation mechanisms(stacking fault networks and phase transformation)also provide additional strengthening and toughening of the subsurface *** features make the CoCrNi alloy particularly wear resistant at cryogenic conditions and an excellent candidate for safety–critical applications.

关键词： Multi-principal element alloy Cryogenic temperature Wear CoCrNi

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