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Machine Learning for heat radiation modeling of bi-and polydisperse particle systems including walls

Particuology 2023年第3期74卷 119-140页

作者： Josef Tausendschön Gero Stöckl Stefan Radl Institute of Process and Particle Engineering Graz University of TechnologyInffeldgasse 13/III8010GrazAustria

We investigated the ability of four popular Machine Learning methods i.e.,Deep Neural Networks(DNNs),Random Forest-based regressors(RFRs),Extreme Gradient Boosting-based regressors(XGBs),and stacked ensembles of DNNs,to model the radiative heat transfer based on view factors in bi-and polydisperse particle beds including *** training and analyzing the predictive capability of each method,an adjustment of markers used in monodisperse systems,as well as an evaluation of new markers was *** the basis of our dataset that considers a wide range of particle radii ratios,system sizes,particle volume fractions,as well as different particle-species volume fractions,we found that(i)the addition of particle size information allows the transition from monodisperse to bi-and polydisperse beds,and(ii)the addition of particle volume fraction information as the fourth marker leads to very accurate *** terms of the overall performance,DNNs and RFRs should be preferred compared to the other two *** particle-particle view factors,DNN and RFR are on par,while for particle-wall the RFR is *** demonstrate that DNNs and RFRs can be built to meet or even exceed the prediction quality standards achieved in a monodisperse system.

关键词： Discrete element method(DEM) Heat radiation modeling Machine learning View factors Wall radiation Polydisperse particles

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Implementation and validation of a bonded particle model to predict rheological properties of viscoelastic materials

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Particuology 2024年第6期89卷 198-210页

作者： Michael Mascara Arno Mayrhofer Stefan Radl Christoph Kloss Institute of Process and Particle Engineering Graz University of TechnologyInffeldgasse 13Graz8010Austria DCS Computing GmbH Industriezeile 35Linz4020Austria

This work focuses on implementing a particle-based method able to characterize viscoelastic materials whose rheological properties,such as storage modulus G′and loss modulus G″,are *** is based on the bonded particle model,with the elastic constitutive relation here substituted with a viscoelastic one to capture time-scale *** Burgers model,vastly used in literature to model viscoelastic systems,is discretized and *** test case used for calibration comprises of a cubic lattice,sheared with a periodic motion,to mimic the effect of a shear *** appropriate filtering of the stress response,the rheological properties are obtained,highlighting the effect of the lattice geometry,as well as the particle size,on the accuracy of the ***,the Burgers parameters are calibrated by analytically fitting the experimental dataset,showing the limitation of the Burgers *** micro-contact parameters are obtained from the macro parameters through appropriate *** completing a frequency sweep,the simulated G′and G″show a relatively large error,around 25%for G’for *** this reason,a more robust model,namely the generalized Maxwell model,has been *** calibration procedure is performed in the same fashion as for the Burgers ***,the tangential micro-contact parameters are scaled *** normal *** scaling parameter,calledα,is calibrated by minimizing the root mean square error between simulation and experimental data,giving errors below 10%in both G′and G″for a large ***,a full ring plate-plate rheometer setup is simulated,and the simulation is compared with the given experimental dataset,again finding a good agreement.

关键词： DEM Rheology Numerical modeling Viscoelasticity

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Predictions of the P1 approximation for radiative heat transfer in heterogeneous granular media

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Particuology 2023年第11期82卷 25-47页

作者： Jelena Macak Christoph Goniva Stefan Radl DCS Computing GmbH 4020LinzAustria Graz University of Technology Institute of Process and Particle Engineering8010GrazAustria

The P1 approximation is a computationally efficient model for thermal ***,we present a P1 formulation in the context of the combined computational fluid dynamics and discrete element method(CFD-DEM),including closures for dependent scattering and *** available analytical and semi-analytical solutions,we find agreement for steady-state and transient quantities in sizedisperse *** flux is identified as the most sensitive quantity to predict,displaying unphysical spatial *** oscillations are due to a temperature slip at the locations of abrupt change in solid *** propose two techniques that mitigate this effect:smoothing of the radiative properties,and ***,using up to a million times enlarged particles,we demonstrate practically limitless compatibility with ***,we compare predictions made with our code to experimental data for a pebble bed under vacuum conditions,and in presence of *** find that a carefully calibrated simulation can replicate trends observed in experiments,with relative temperature error of less than 10%.

关键词： CFD-DEM Thermal radiation Coarse-graining P1 Pebble bed nuclear reactor

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Development of a Digital Interface for Personalized Dosing in Renal Impaired Patients: A Case-Study Using the ACE-Inhibitor Benazepril

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Studies in Health technology and Informatics 2023年 301卷 133-139页

作者： Reinisch, Valerie Paudel, Amrit Pinto, Joana T. Research Center Pharmaceutical Engineering GmbH Graz Austria Institute for Process and Particle Engineering University of Technology Graz Austria

ISBN: (纸本)9781643683867

Background: Personalized dosing regimens have great potential to improve the standard level of care from "one-fits-all" to the "right dose, to the right patient at the right time". Objectives: Development of a digital interface that can inform healthcare professionals on the dosing of an ACE inhibitor on an individual basis. Methods: A physiologically based pharmacokinetic (PBPK) model and a one-compartment model were implemented for the prodrug benazepril and its metabolite benazeprilat, respectively. In sequence, to capture inter-individual differences the models were extended to a population based one (PopPBPK). Results: Both models predicted the pharmacokinetic data in the observed ranges. Application of the models help identify the factors influencing drug concentrations in the body and to find subgroups of patients, in which a dose adjustment is recommended, or a higher degree of caution is required. Conclusion: The use of the models via a practical user interface can help inform clinical decisions and design optimal dosing based on the individual anthropometric characteristics and stage of renal impairment. © 2023 The authors, AIT Austrian institute of technology and IOS Press.

关键词： User interfaces

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DEM-Based Analysis of Fatigue-Induced Damage Using a Cycle-Jump Technique 20th

DEM-Based Analysis of Fatigue-Induced Damage Using a Cycle-J...

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20th fib Symposium on ReConStruct: Resilient Concrete Structures, 2024

作者： Rybczynski, Sebastian Schaan, Gunnar Skorych, Vasyl Ritter, Martin Schmidt-Döhl, Frank Institute of Materials Physics and Chemistry of Buildings Hamburg University of Technology Germany Electron Microscopy Unit Hamburg University of Technology Germany Institute of Solids Process Engineering and Particle Technology Hamburg University of Technology Germany

ISBN: (纸本)9782940643257

This paper examines experimental and numerical findings regarding the fatigue characteristics of ultra-high performance concrete (UHPC). To provide detailed characterisation of fatigue-induced damage, UHPC specimens underwent analysis using scanning and transmission electron microscopy (SEM and TEM). Results demonstrated that a densification of the binder matrix occurs accompanied by a transformation of nanoscale ettringite, and the content of unhydrated cement clinker influences the fatigue resistance of UHPC. Numerical investigations of the mechanical behavior of UHPC employed the bonded-particle model (BPM), calibrated with experimental data. The mesoscopic BPM model comprises three phases: matrix, ITZ (interfacial transition zone), and aggregate. A novel rheological fatigue formulation for binder and ITZ bonds was developed to introduce minor scale variations and plastic deformations, accurately replicating fatigue behavior. Additionally, a cyclic-jump technique enabled the analysis of both low-cycle and high-cycle simulations. © fédération internationale du béton (fib).

关键词： Fatigue damage

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MP-PIC simulation of circulating fluidized beds using an EMMS based drag model for Geldart B particles

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Particuology 2021年第6期19卷 76-90页

作者： Timo Dymala Tom Wytrwat Stefan Heinrich Hamburg University of Technology Institute of Solids Process Engineering and Particle TechnologyDenickestr.1521073 HamburgGermany

In this study the multiphase particle-in-cell(MP-PIC)method is used for the simulation of two pilot-scale circulating fluidized beds(CFBs)with quartz sand belonging to Geldart’s group B as bed *** simulations were performed using a homogeneous drag model as well as a structure dependent drag model based on the energy minimization multi-scale method(EMMS).The results are compared with experimental data from literature as well as *** simulations with the EMMS based drag model show a good agreement of the time-averaged axial solids concentration,circulation rate and riser pressure ***,a lower grid sensitivity is observed compared to the homogeneous drag *** contrast to the conventional drag model a dense bottom zone is predicted by the EMMS based drag *** overprediction of the solid concentration in the dense bottom zone is presumably due to an overprediction of the cluster diameter that is calculated using an empirical cluster diameter *** shows the necessity for a new meso-scale cluster correlation for the simulation of Geldart B ***,the results of the time-averaged radial solids concentration differ from the expectations of a core-annulus flow indicating that a mesh refinement at the walls is ***,the importance of using a realistic particle size distribution is identified.

关键词： 3D-CFD simulation Circulating fluidized bed(CFB) Multiphase particle-in-cell method(MP-PIC) Energy minimizing multi-scale theory(EMMS) Validation study

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A brief review of preparation and applications of monolithic aerogels in atmospheric environmental purification

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Journal of Environmental Sciences 2025年第3期149卷 209-220页

作者： Linfeng Nie Shuangde Li Mengjie Cao Ning Han Yunfa Chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Science&Technology on Particle Materials Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Monolithic aerogels are promising candidates for use in atmospheric environmental purification due to their structural advantages,such as fine building block size together with high specific surface area,abundant pore structure,***,monolithic aerogels possess a unique monolithic macrostructure that sets them apart from aerogel powders and nanoparticles in practical environmental clean-up *** review delves into the available synthesis strategies and atmospheric environmental applications of monolithic aerogels,covering types of monolithic aerogels including SiO_(2),graphene,metal oxides and their combinations,along with their preparation *** particular,recent developments for VOC adsorption,CO_(2)capture,catalytic oxidation of VOCs and catalytic reduction of CO_(2)are ***,challenges and future opportunities for monolithic aerogels in the atmospheric environmental purification field are *** reviewprovides valuable insights for designing and utilizing monolithic aerogel-based functional materials.

关键词： Monolithic aerogel Environmental purification Catalysis Adsorption

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Integrated high-performance and accurate shaping technology of low-cost powder metallurgy titanium alloys: A comprehensive review

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 413-426页

作者： Xuemeng Gan Shaofu Li Shunyuan Xiao Yafeng Yang State Key Laboratory of Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Science and Technology on Particle Materials Chinese Academy of SciencesBeijing 100190China

The practical engineering applications of powder metallurgy (PM) Ti alloys produced through cold compaction and pressure-less sintering are impeded by poor sintering densification, embrittlement caused by excessive O impurities, and severe sintering deforma-tion resulting from the use of heterogeneous powder mixtures. This review presents a summary of our previous work on addressing the above challenges. Initially, we proposed a novel strategy using reaction-induced liquid phases to enhance sintering densification. Near- complete density (relative density exceeding 99%) was achieved by applying the above strategy and newly developed sintering aids. By focusing on the O-induced embrittlement issue, we determined the onset dissolution temperature of oxide films in the Ti matrix. On the basis of this finding, we established a design criterion for effective O scavengers that require reaction with oxide films before their dissol-ution. Consequently, a ductile PM Ti alloy was successfully obtained by introducing 0.3wt% NdB6 as the O scavenger. Lastly, a powder- coating strategy was adopted to address the sintering deformation issue. The ultrafine size and shell-like distribution characteristics of coating particles ensured rapid dissolution and homogeneity in the Ti matrix, thereby facilitating linear shrinkage during sintering. As a result, geometrically complex Ti alloy parts with high dimensional accuracy were fabricated by using the coated powder. Our fundament-al findings and related technical achievements enabled the development of an integrated production technology for the high-performance and accurate shaping of low-cost PM Ti alloys. Additionally, the primary engineering applications and progress in the industrialization practice of our developed technology are introduced in this review.

关键词： powder metallurgy titanium sintering densification oxygen scavenging accurate shaping

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Highly efficient ozone elimination by metal doped ultra-fine Cu_(2)O nanoparticles

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Journal of Environmental Sciences 2023年第12期134卷 108-116页

作者： Anqi Wang Le Zhang Jian Guan Xiaoze Wang Guojun Ma Guijun Fan Hang Wang Ning Han Yunfa Chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Science&Technology on Particle Materials Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

Nowadays,ozone contamination becomes dominant in air and thus challenges the research and development of cost-effective *** this study,metal doped Cu_(2)O catalysts are synthesized via reduction of Cu^(2+)by ascorbic acid in base solutions containing doping metal *** results show that compared with pure Cu_(2)O,the Mg^(2+)and Fe^(2+)dopants enhance the O_(3)removal efficiency while Ni2+depresses the *** specific,Mg-Cu_(2)O shows high O3removal efficiency of 88.4%in harsh environment of 600,000 mL/(g·hr) space velocity and 1500 ppmV O_(3),which is one of the highest in the *** and electron paramagnetic spectroscopy characterization shows higher concentration of crystal defects induced by the Mg^(2+)dopants,favoring the *** in-situ diffuse reflectance Fourier transform infrared spectroscopy shows the intermediate species in the O_(3)degradation process change from O_(2)^(2-)dominant of pure Cu_(2)O to O_(2)^(-)dominant of Mg-Cu2O,which would contribute to the high *** these results show the promising prospect of the Mg-Cu_(2)O for highly efficiency O_(3)removal.

关键词： Ozone catalyst Cu_(2)O Dopant Ultra-fine nanoparticles

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Synthesis ofδ-MnO_(2)via ozonation routine for low temperature formaldehyde removal

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Journal of Environmental Sciences 2025年第1期147卷 642-651页

作者： Guijun Fan Yacong Guo Shaohua Chai Le Zhang Jian Guan Guojun Ma Ning Han Yunfa Chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China College of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Science and Technology on Particle Materials Institute of Process EngineeringChinese Academy of SciencesBeijing 361021China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Petrochemical Engineering&Environment Zhejiang Ocean UniversityZhoushan 316022China

Nowadays,it is still a challenge to prepared high efficiency and low cost formaldehyde(HCHO)removal catalysts in order to tackle the long-living indoor air ***,δ-MnO_(2)is successfully synthesized by a facile ozonation strategy,where Mn^(2+)is oxidized by ozone(O_(3))bubble in an alkaline *** presents one of the best catalytic properties with a low 100%conversion temperature of 85℃for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr).As a comparison,more than 6 times far longer oxidation time is needed if O3 is replaced by O_(2).Characterizations show that ozonation process generates a different intermediate of tetragonalβ-HMnO_(2),which would favor the quick transformation into the final productδ-MnO_(2),as compared with the relatively more thermodynamically stable monoclinicγ-HMnO_(2)in the O_(2)***,HCHO is found to be decomposed into CO_(2)via formate,dioxymethylene and carbonate species as identified by room temperature insitu diffuse reflectance infrared fourier transform *** these results show great potency of this facile ozonation routine for the highly activeδ-MnO_(2)synthesis in order to remove the HCHO contamination.

关键词： δ-MnO_(2) Ozone oxidation HCHO oxidation In-situ DRIFTS

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