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Influence of aging, morphology and particle size on the behavior of microplastics during magnetic seeded filtration

Science of the Total Environment 2024年 957卷 177353页

作者： Kaiser, Steffen Kaegi, Ralf Rhein, Frank Karlsruhe Institute of Technology Institute of Mechanical Process Engineering and Mechanics Strasse am Forum 8 Karlsruhe76131 Germany Swiss Federal Institute of Aquatic Science and Technology Ueberlandstrasse 133 Dübendorf8600 Switzerland

Magnetic seeded filtration (MSF) is a solid-liquid separation process based on the formation of hetero-agglomerates between target (non-magnetic) particles and added magnetic particles, followed by magnetic separation. Previous experimental studies reported high separation efficiencies for hydrophobic microplastic particles (MP) and focused mainly on the polymer type. This study investigates the influence of the particle size, morphology and aging on the separation efficiency of different polymer types. Surface morphology and particle size only marginally affect the separation of particles larger than 30μm. However, the agglomeration of particles in the lower micron range is increasingly dominated by repulsive electrostatic interactions. After oxidative treatment with Fenton's reagent, separation efficiencies for most MP remain between 55% and 96%. Exposure to UV light results in a significant decrease in separation efficiency, particularly for polystyrene, where the separation efficiency decreases from 86% to 9%. Mechanical aging, simulated by mixing MP in a sand matrix on a horizontal shaker, reduces the separation to below 50% for all polymer types. Exposure to UV light causes surface oxidation, as evidenced by the formation of carbonyl peaks in the Fourier transformed infrared spectra. Mechanical treatment results in the deposition of small silica particles on the MP surface, as revealed by electron microscopy. Both mechanisms render the polymer surface more hydrophilic and reduce the tendency to form hetero-agglomerates with (hydrophobic) magnetic seed particles. MSF is a promising technique for MP separation but also offers the possibility to probe surface properties of (environmentally aged) MPs. This study demonstrates that environmental aging can significantly affect the behavior of MP and highlights the importance of environmental aging in MP fate studies. © 2024 The Author(s)

关键词： Magnetic bubbles

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A NOVEL MODEL FOR DIRECT NUMERICAL SIMULATION OF SUSPENSION DYNAMICS WITH ARBITRARILY SHAPED CONVEX PARTICLES

arXiv

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arXiv 2024年

作者： Marquardt, Jan E. Hafen, Nicolas Krause, Mathias J. Lattice Boltzmann Research Group Institute of Mechanical Process Engineering and Mechanics Karlsruhe Institute of Technology Karlsruhe76131 Germany Lattice Boltzmann Research Group Institute for Applied and Numerical Mathematics Karlsruhe Institute of Technology Karlsruhe76131 Germany

This study presents an innovative direct numerical simulation approach for complex particle systems with irregular shapes and large numbers. Using partially saturated methods, it accurately models arbitrary shapes, albeit at considerable computational cost when integrating a compatible contact model. The introduction of a novel parallelization strategy significantly improves the performance of the contact model, enabling efficient four-way coupled simulations. Through hindered settling studies, the criticality of the explicit contact model for maintaining simulation accuracy is highlighted, especially at high particle volume fractions and low Archimedes numbers. The feasibility of simulating thousands of arbitrarily shaped convex particles is demonstrated with up to 1934 surface-resolved particles. The study also confirms the grid independence and linear convergence of the method. It shows for the first time that cube swarms settle 13 to 26% slower than swarms of volume-equivalent spheres across different Archimedes numbers (500 to 2000) and particle volume fractions (10 to 30%). These findings emphasize the shape dependence of particle systems and suggest avenues for exploring their nuanced dynamics. Copyright © 2024, The Authors. All rights reserved.

关键词： Direct numerical simulation

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An integrated flexible self-healing Zn-ion battery using dendrite-suppressible hydrogel electrolyte and free-standing electrodes for wearable electronics

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Nano Research 2023年第8期16卷 11000-11011页

作者： Jiawei Long Tianli Han Xirong Lin Yajun Zhu Yingyi Ding Jinyun Liu Huigang Zhang Key Laboratory of Functional Molecular Solids Ministry of EducationCollege of Chemistry and Materials ScienceAnhui Normal UniversityWuhu 241002China National Key Laboratory of Science and Technology on Micro/Nano Fabrication Department of Micro/Nano-electronicsShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Among many aqueous batteries,flexible zinc-ion(Zn-ion)battery becomes the focus owing to the merits of low cost,non-toxicity,and ***,a Zn dendrite-suppressible hydrogel electrolyte with both flexible and self-healing properties is developed via photoinitiated *** cross-linked structure of the polyacrylamide-N,N'-methylenebisacrylamide(PAM-MBA)-Zn/Mn hydrogel endows an enlarged chemical stable window,high ionic conductivity,and low polarization *** cycling at the current density of 0.5 mA·cm^(−2)for 250 h,Zn‖Zn symmetrical cell based on PAM-MBA-Zn/Mn electrolyte delivers a low polarization of 40 *** suppressed dendrite growth is ascribed to the uniform Zn deposition/stripping on *** galvanostatic intermittent titration technique curves display that the Zn-ion battery constructed by the PAM-MBA-Zn/Mn hydrogel electrolyte,free-standing FeVO_(4)/carbon cloth cathode,and Zn nanosheets/carbon cloth anode presents low reaction resistance and fast diffusion coefficient,indicating good endurance of cycling at high current *** battery with PAM-MBA-Zn/Mn hydrogel electrolyte presents a good flexible and self-healing *** bending 0°,60°,90°,and 180°for 30 times,batteries deliver stable *** cutting into ten pieces,the battery could self-heal and display a potential retention of 93.7%compared to the fresh cell.A good rate-performance is also *** cutting/healing three times during cycling,capacity recovers well compared to the first-time cutting/***,the battery exhibits good flexibility using in an electric watch,indicating a promising potential for wearable electronics.

关键词： Zn-ion battery flexible self-healing dendrite growth cycling life

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Feedforward control of flat hybrid automata: a behavioral systems theory approach

Feedforward control of flat hybrid automata: a behavioral sy...

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IEEE Conference on Decision and Control

作者： Frederik Zahn Tobias Kleinert Veit Hagenmeyer Institute for Automation and Applied Informatics Karlsruhe Institute of Technology Karlsruhe Germany Chair of Process Control Engineering RWTH Aachen University Aachen Germany

ISBN: (数字)9798350316339

ISBN: (纸本)9798350316346

Differential flatness has been defined in the literature for continuous time dynamical systems and for discrete time systems. We define flatness of automata from the perspective of behavioral systems theory, and synthesize a flatness definition for hybrid automata. These new definitions allow for feedforward trajectory generation for flat hybrid automata. Additionally, we provide necessary and sufficient conditions of hybrid automaton flatness for different types of continuous state constraints and switching conditions, and how to compute whether a hybrid automaton is flat. We illustrate feedforward trajectory generation based on our findings for a robotic manipulator example.

关键词： Discrete-time systems Sufficient conditions Automata Switches Manipulators Control systems Hybrid power systems Trajectory Feedforward systems Dynamical systems

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Origin of non-uniform plasticity in a high-strength Al-Mn-Sc based alloy produced by laser powder bed fusion

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Journal of Materials Science & technology 2022年第8期103卷 121-133页

作者： Dina Bayoumy Kwangsik Kwak Torben Boll Stefan Dietrich Daniel Schliephake Jie Huang Junlan Yi Kazuki Takashima Xinhua Wu Yuman Zhu Aijun Huang Monash Centre for Additive Manufacturing 15-17 Normanby RdNotting HillVIC 3168Australia Department of Materials Science and Engineering Monash UniversityClaytonVIC 3800Australia Department of Materials Science and Engineering Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan Karlsruhe Nano Micro Facility(KNMF) Karlsruhe Institute of Technology(KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany Institute for Applied Materials(IAM-WK) Karlsruhe Institute of Technology(KIT)Engelbert-Arnold-Straße 476131 KarlsruheGermany Aeronautical Manufacturing Technology Institute Shanghai Aircraft Manufacturing Co.Ltd.Shanghai 201324China

The Al-Mn-Sc-based alloys specific for additive manufacturing(AM)have been recently developed and can reach ultrahigh strength and adequate ***,these alloys commonly exhibit nonuniform plasticity during tensile deformation,which is a critical issue hindering their wider *** this work,the origin of this non-uniform plasticity of the alloys produced by laser powder bed fusion(LPBF)has been systematically investigated for the first *** results show that the loss of uniform plasticity in the alloy originates from microstructural regions containing equiaxed fine-grains(FGs)(~650nm in size)at the bottom of the melt *** micro-tensile tests,the strength of these FG regions can reach a peak of~630 *** this,an apparent yield drop occurs,followed by rapid strain *** FG behavior is associated with intermetallic particles along grain boundaries and a lack of uniform mobile dislocations during *** columnar coarse-grain(CG)regions in the remaining melt pools show uniform plasticity and moderate work ***,the quantitative calculations indicate that the solid solution strengthening in these two regions is ***,secondary Al_(3)Sc precipitates contribute to~260 MPa strength in the FG,compared to 310 MPa in the CG due to their different number *** addition,grain boundary strengthening can reach 230 MPa in the FG region;nearly double the CG region value.

关键词： Aluminium alloy Laser powder bed fusion Crystal plasticity microstructures Strengthening

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Plug & Produce - A 3D-printed sensor system concept combined with cloud-based process monitoring for data-driven decision support 16

Plug & Produce - A 3D-printed sensor system concept combined...

引用

16th CIRP Conference on Intelligent Computation in Manufacturing engineering, CIRP ICME 2022

作者： Sidarava, Valeryia Backenstos, Maximilian Rehfeldt, Sebastian Klein, Harald Technical University of Munich TUM School of Engineering and Design Department of Energy and Process Engineering Institute of Plant and Process Technology Boltzmannstr. 15 Garching85748 Germany DatenBerg GmbH Haid-Und-Neu-Straße 7 Karlsruhe76131 Germany

Digitalization of industrial processes has become a more pressing issue in recent years. As complex industrial operations are improved by data-driven decision support, the availability of process data is a key requirement. This contribution describes a concept for flexible and cost-effective sensing systems and subsequent data processing. Application of additive manufacturing, IO-Link technology, and cloud-based analysis allows for high degrees of customizability and assembly simplification. An example is given for decision support facilitated by the aforementioned system in the area of process control. The proposed concept offers a simple plug-and-produce solution for cross-industry process monitoring and analytics. © 2023 Elsevier B.V.. All rights reserved.

关键词： process monitoring

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Nanoindentation Characterization of Creep-fatigue Interaction on Local Creep Behavior of P92 Steel Welded Joint

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Chinese Journal of Mechanical engineering 2021年第6期34卷 85-97页

作者： Yuxuan Song Yi Ma Zhouxin Pan Yuebing Li Taihua Zhang Zengliang Gao Institute of Process Equipment and Control Engineering College of Mechanical EngineeringZhejiang University of TechnologyHangzhou 310014China Institute of Micro/Nano‑Mechanical Testing Technology&Application College of Mechanical EngineeringZhejiang University of TechnologyHangzhou 310014China Institute of Solid Mechanics Beihang UniversityBeijing 100000China Engineering Research Center of Process Equipment and Re‑manufacturing Ministry of EducationHangzhou 310014China

In modern fossil and nuclear power plants,the components are subjected to creep,fatigue,and creep-fatigue(CF)due to frequent start-up and shut-down operations at high *** CF interaction on the in-service P92 steel welded joint was investigated by strain-controlled CF tests with different dwell times of 30,120,300,600 and 900 s at 650℃.Based on the observations of the fracture surface by scanning electron microscope(SEM),the character-istic microstructure of fatigue-induced damage was found for the CF specimens with short dwell times(30 and 120 s).The hardness,elastic modulus and creep deformation near the fracture edges of four typical CF specimens with 30,120,600 and 900 s dwell times were measured by *** to specimens with post-weld heat treatment(PWHT),lower hardness and creep strength were found for all CF *** addition,significant reduc-tions in hardness,elastic modulus,and creep strength were measured near the fracture edges for the CF specimens with short dwell times compared to the PWHT *** to PWHT specimens(0.007),the increased strain rate sensitivities(SRS)of 0.010 to 0.17 were estimated from secondary *** increased values of SRS indicate that the room temperature creeps behavior is strongly affected by the decrease in dislocation density after the CF tests.

关键词： P92 steel Welded joint Creep-fatigue interaction Nanoindentation Creep behavior

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Optimization of Single Node Load Balancing for Lattice Boltzmann Methods on Heterogeneous High Performance Computers

SSRN

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SSRN 2024年

作者： Kummerländer, Adrian Bukreev, Fedor Teutscher, Dennis Dorn, Marcio Krause, Mathias J. Institute of Applied and Numerical Mathematics Karlsruhe Institute of Technology Karlsruhe Germany Institute for Mechanical Process Engineering and Mechanics Karlsruhe Institute of Technology Karlsruhe Germany Lattice Boltzmann Research Group Karlsruhe Institute of Technology Karlsruhe Germany Instituto de Informática Universidade Federal do Rio Grande do Sul Porto Alegre Brazil

Lattice Boltzmann Methods (LBM) are particularly suited to highly parallel computational fluid dynamics simulations both on SIMD CPUs and GPUs. While heterogeneous systems combining CPUs and GPUs are ubiquitous in high performance computation (HPC), the computationally dominant collide-and-stream loop commonly only utilizes either CPUs or GPUs homogeneously. This article proposes a novel approach utilizing genetic programming for cost-aware optimization of spatial domain decompositions targeting heterogeneous execution environments. The implementation and performance of the genetic algorithm for spatial decomposition, as well as the subsequently derived rank assignment approaches, are discussed in detail. The resulting comprehensive load balancing strategy is implemented in the open source LBM framework OpenLB and applied to turbulent flow reference cases, including a multi-physics reactive mixer benchmark. Evaluation of its computational performance on heterogeneous HPC nodes yields speedups up to 87% compared to homogeneous GPU-only execution. © 2024, The Authors. All rights reserved.

关键词： Genetic programming

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Controllability and Optimal Control of Water Networks – A Comparison of Three Lumped Models

Controllability and Optimal Control of Water Networks – A C...

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American Control Conference (ACC)

作者： Henry Baumann Alexander Schaum Thomas Meurer Digital Process Engineering Group MVM Karlsruhe Institute of Technology Karlsruhe Germany Department for Process Analytics Computational Science Hub University of Hohenheim Stuttgart Germany

ISBN: (数字)9798350382655

ISBN: (纸本)9798350382662

When large scale systems or transport networks, which are accurately modelled by partial differential equations, should be steered using optimization-based controllers, reduced order models are typically utilized to describe the plant dynamics in a fast but sufficiently accurate manner. Three different approximative models for water systems are recalled and used for the lumped description of an exemplary network for which, in addition, a structural controllability analysis is carried out. For the approximate models optimal control problems are solved and the results are compared for both, open and closed loop scenarios to evaluate accuracy, calculation time and parametrization effort of the reduced models. The results are visualized on the basis of numerical experiments for a test scenario.

关键词： Visualization Tracking loops Accuracy Computational modeling Optimal control Controllability Mathematical models

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Impact of Particle Size Distribution on the Rest Phase Behavior of Lib Cathodes – Model Based Analysis

SSRN

引用

SSRN 2023年

作者： Fath, Maximilian Heidebrecht, Peter Drechsler, Carsten Kamlah, Marc Center of Expertise of reaction engineering BASF SE Ludwigshafen67056 Germany Institute of Thermal Process Engineering Karlsruhe Institute of Technology Karlsruhe76131 Germany Institute for Applied Materials Karlsruhe Institute of Technology Karlsruhe76131 Germany

Dynamic measurements like the galvanostatic intermittent titration technique (GITT), pulse response measurements and current interruption methods are widely used for the parametrization of battery and electrode models, under the assumption of a single, representative particle size. These methods are based on analyzing the development of the cell potential in response to a change in the galvanostatic current, as dedicated test protocols are realized via the combination of a charge/discharge phase of defined duration with an open circuit rest phase. In this model study, the effect of a particle size distribution as well as the impact of the local open circuit potential slope on the rest-phase potential are modelled by means of the extended Doyle-Fuller-Newman model. This allows for a more accurate design of relaxation experiments and provides a framework to interpret frequently observed deviations between electrochemical experiments and reduced order simulations. © 2023, The Authors. All rights reserved.

关键词： Particle size analysis

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