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Particle mixing rates using the two-fluid model

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Particuology 2018年第1期16卷 13-26页

作者： m. Banaei N.G. Deen m. van Sint Annaland j.a.m. kuipers multiphase Reactors Group Deportment of Chemical Engineering & Chemistry Eindhoven University of Technology 5600 MB Eindhoven The Netherlands Dutch Polymer Institute (DPI) 5600 AX Eindhoven The Netherlands multiphase and Reactive Flows Group Department of Mechanical Engineering Eindhoven University of Technology 5600 MB Eindhoven The Netherlands

In this work, a new methodology is introduced to calculate the solids mixing rate in dense gas-fluidized beds using the two-fluid model. The implementation of this methodology into an existing two-fluid model code was carefully verified. The solids phase continuity equation was satisfied using our method, and the sensitivity of the computational results to the time step, computational cell size, and discretization scheme was investigated to determine the optimal simulation settings. Using these simulation settings, the degree of solids mixing was observed to rapidly （exponentially） increase with increasing operating pressure and linearly decrease with increasing bed diameter. Our novel methodology can be applied to analyze mixing processes in large lab-scale beds as an alternative to existing time-consuming simulation techniques such as computational fluid dynamics combined with the discrete element model.

关键词： Gas-solid fluidized bed Simulation Two-fluid model Solids mixing Pressure Scale up

Borescopic particle image velocimetry in bubbling gas-solid fluidized beds

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Particuology 2019年第2期17卷 66-75页

作者： m. Banaei R. Dellaert N.G. Deen j.a.m. kuipers m. van Sint Annaland multiphase Reactors Group Department of Chemical Engineering & Chemistry Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands Dutch Polymer Institute (DPI) P.O. Box 902 5600 AX Eindhoven The Netherlands multiphase and Reactive Flows Group. Department of mechanical Engineering Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven The Netherlands

In this work, the borescopic particle image velocimetry (BPIV) technique was applied to a bubbling gas-solid fluidized bed, and the results were compared with published positron emission particle tracking (PEPT) measurement data. Before performing the experiments, the sensitivity of the BPIV results to the illumination power, light reflectivity of the particles, and location of the borescope was also investigated. The BPIV and PEPT results were in fair agreement;however, some discrepancies were *** difference between the two sets of results were mainly caused by the intrusiveness of BPIV, the fact that the local solids volume fraction was not accounted for in the BPIV analysis, and the intrinsic differences of these two methods. Therefore, measurement of the local solids volume fraction with the borescope is highly recommended for further development of the BPIV method, which will also enable measureme nt of the local solids mass fluxes in side dense gas-solid fluidized beds.

关键词： Borescopic particle image velocimetry Gas-solid bubbling fluidized bed Solid velocity profile Experimental investigation Hydrodynamics

Gas–solid interaction force from direct numerical simulation (DNS) of binary systems with extreme diameter ratios

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Particuology 2009年第4期7卷 233-237页

作者： S. Sarkar S.H.L. Kriebitzsch m.A. van der Hoef j.a.m. kuipers Department of Science and Technology University of Twente P.O. Box 217 7500 AE Enschede The Netherlands

Fluid-particle systems as commonly encountered in chemical, metallurgical and petroleum industries are mostly polydisperse in nature. However, the relations used to describe fluid-particle interactions are originally derived from monodisperse systems, with ad hoc modifications to account for polydispersity. In previous work it was shown that for bidisperse systems with moderate diameter ratios of 1：2 to 1：4, this approach leads to discrepancies, and a correction factor is needed. In this work we demonstrate that this correction factor also holds for more extreme diameter ratios of 1：5, 1：7 and 1： 10, although the force on the large particles is slightly overestimated when using the correction factor. The main origin of the correction is that the void surrounding the large particles becomes less in case ofa bidisperse mixture, as compared to a monodisperse system with the same volume fraction. We further investigated this discrepancy by calculating the volume per particle by means of Voronoi tessellation.

关键词： Bidisperse Fluid-particle interaction force Lattice Boltzmann simulation Direct numerical simulation

Coefficient of restitution for particles impacting on wet surfaces： An improved experimental approach

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Particuology 2016年第2期14卷 1-9页

作者： B. Cunger V. Salikov S. Heinrich S. Antonyuk V.S. Sutkar N.G. Deen j.a.m. kuipers Institute of Solids Process Engineering and Particle Technology Hamburg University of Technology Denickestrasse 15 21073 Hamburg Germany Particle Process Engineering Department of Mechanical and Process Engineering University ofKaiserslautern Cottlieb-Daimler-Strasse 67663 Kaiserslautern Germany multiphase Reactors Group Department of Chemical Engineering and Chemistry Eindhoven University of Technology P.O. Box 513 5600 MB EindhovenThe Netherlands

The coefficient of restitution is widely used to characterize the energy dissipation rate in numerical simulations involving particle collisions. The challenge in measuring the coefficient of restitution is the strong scatter seen in experimental data that results from varying particle properties, i.e. shape and surface roughness, and from imperfections in the experimental technique. To minimize this scattering, a novel experimental setup was developed based on two synchronized high-speed cameras capturing the collision behaviour of a particle in three dimensions. To measure the wet restitution coefficient, which describes particle impact in the presence of a liquid layer in the contact region, additional accuracy can be achieved by measuring the liquid layer thickness by a high-precision optical confocal sensor. The coefficient of restitution was measured for glass particles with two different diameters, at different relative velocities and liquid layer thicknesses, with a focus on small collision velocities and thin liquid layers, using both the improved （three dimensional） and the conventional （two dimensional） approaches to quantify the improvement of the new method＇s accuracy.

关键词： Particle impact Coefficient of restitution Liquid layer Improved experimental setup

Brain-penetrating neurotrophic factor mimetics: HER-096 as a disease-modifying therapy for Parkinson’s disease

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Neural Regeneration Research 2025年第4期20卷 1094-1095页

作者： Natalia Kulesskaya Kira m.Holmström Henri j.Huttunen Herantis Pharma Plc EspooFinland

Neurotrophic factors as a therapeutic approach in neurodegenerative diseases:A major unmet need in the field of central nervous system diseases is disease-modifying *** for decades there have been various symptomatic treatments available to alleviate the symptoms of the disease,disease-modification,*** that stop,significantly delay,or reverse the progression of the disease,has been turned out to a difficult goal to achieve.

关键词： diseases treatment therapeutic

The effect of adsorbent textural and functional properties on model naphthenic acid adsorption

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journal of Environmental Sciences 2025年第2期148卷 27-37页

作者： Tyler m.Roy Elmira Nazari Oliver K.L.Strong Paul R.Pede Andrew j.Vreugdenhil material Science Department of ChemistryTrent University1600 West BankPeterboroughOntario K9L 0G2Canada Carbonix 690 Mountain RdSuite 200Fort William First NationOntario P7J 1G8Canada

Naphthenic acids,NAs,are a major contaminant of concern and a focus of much research around remediation of oil sand process affected waters,*** activated carbon adsorbents are an attractive option given their low cost of fabrication and implementation.A deeper evaluation of the effect NA structural differences have on uptake affinity is *** we provide an in-depth exploration of NA adsorption including many more model NA species than have been assessed previously with evaluation of adsorption kinetics and isotherms at the relevant alkaline pH of OSPW using several different carbon adsorbents with pH buffering to simulate the behaviour of real *** for the NA varied considerably regardless of the activated carbon used,ranging from 350 mg/g to near zero highlighting recalcitrant *** equilibrium data was explored to identify structural features of these species and key physiochemical properties that influence *** found that certainNAwill be resistant to adsorptionwhen hydrophobic adsorbents are *** isotherm modelling helped explore interactions occurring at the interface between NA and adsorbent *** identified the importance of NA hydrophobicity for activated carbon *** is also presented that indicates favorable hydrogen bonding between certain NA and surface site hydroxyl groups,demonstrating the importance of adsorbent surface functionality for NA *** research highlights the challenges associated with removing NAs from OSPW through adsorption and also identifies howadsorbent surface chemistry modification can be used to increase the removal efficiency of recalcitrant NA species.

关键词： Adsorption Activated carbon model naphthenic acids Isotherm modelling

Two-fluid modelling for cylindrical fluidized beds using kinetic theory for rough spheres

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Particuology 2020年第3期18卷 25-34页

作者： Lei Yang j.T.Padding j.a.m.kuipers Helmholtz Institute Erlangen-Nürnberg for Renewable Energy(IEK-11) Fürther Straβe 24890429 NurnbergGermany Department of Process and Energy Delft University of Technology2628CB DelftThe Netherlands Department of Chemical Engineering and Chemistry Eindhoven University of Technology5600MB EindhovenThe Netherlands

Recently,we have extended the kinetic theory of granular flow (KTGF) to include friction between the spherical particles and tested it in rectangular *** this study,the extended KTGF implemented in cylindrical coordinates is used to model the more-commonly employed cylindrical bubbling fluidized *** attention is paid to the anti-symmetric part of the velocity gradient in the solids stress *** verification of the implementation,a comparison of the present model in the limit of zero friction with the original (frictionless) KTGF model was ***,simulations of bubbling fluidized beds of inelastic particles were performed using our extended KTGF and an effective KTGF model for inelastic particles of jenkins and *** simulation results show good agreement for the time-averaged solids volume fraction distribution and solids circulation ***,our model is validated by predicting the individual bubble behavior in dense bubbling fluidized beds containing different granular materials in a comparison with experimental data from Verma et al.(2014).The extended KTGF leads to an improved agreement with experimental bubble *** to previous work (Yang et al.,2016b,2017c),and by introducing cylindrical coordinates,the current work demonstrates that the extended KTGF improves predictions for the temporal bubble behavior of cylindrical fluidized beds.

关键词： Fluidization Frictional collision Rough particles Cylindrical bed hydrodynamics Two-fluid model

Sleep as a window to understand and regulate Alzheimer's disease:emerging roles of thalamic reticular nucleus

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Neural Regeneration Research 2025年第6期20卷 1711-1712页

作者： Haoqi Sun Shiqian Shen Robert j.Thomas m.Brandon Westover Can Zhang Department of Neurology Beth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMAUSA Center for Translational Pain Research Department of AnesthesiaCritical Care and Pain MedicineMassachusetis General HospitalHarvard Medical SchoolBostonMAUSA Division of Pulmonary Critical Care and Sleep MedicineDepartment of MedicineBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMAUSA Genetics and Aging Research Unit McCance Center for Brain HealthMass General Institute for Neurodegenerative DiseaseDepartment of NeurologyMassachusetts General HospitalHarvard Medical SchoolBostonMAUSA

Introduction:Alzheimer 's disease(AD) is a common neurodegenerative disorder and the primary cause of dementia. Considerable evidence supports the “amyloid hypothesis,” stating that the pathogenesis of AD is primarily caused by the deposition of amyloid-β(Aβ), which drives tau phosphorylation, neuroinflammation, and neurodegeneration in the brain. The amyloid hypothesis is strengthened by the significant and moderate benefit of lecanemab, a humanized antibody through an anti-amyloid mechanism,showing slowed clinical decline(van Dyck et al.,2023). The recent positive results of anti-amyloid trials have brought back focus on the amyloid hypothesis through biochemical, genetic, and pharmacological approaches(Zhang, 2023).

关键词： Alzheimer inflammation hypothesis

Clinical,laboratory,and therapeutic differences between immunoglobulin E-mediated and non-immunoglobulin E-mediated cow’s milk protein allergy in children

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World journal of Clinical Pediatrics 2025年第1期14卷 78-92页

作者： Hasan m Isa marwa j Abdulnabi Nawra S Naser Fatema N Lahmda Noor m AlAnsari Zahra H Isa Afaf m mohamed Department of Pediatrics Salmaniya Medical ComplexManama 26671Bahrain Department of Pediatrics Arabian Gulf UniversityManama 26671Bahrain Faculty of medicine Mansoura UniversityMansoura 35516Egypt Public Health Directorate Ministry of HealthManama 26671Bahrain

BACKGROUND Although breast milk is ideal for newborns,in some cases,it is replaced with cow’s milk,which contains proteins that increase the risk of cow’s milk protein allergy(CmPA).AIm To evaluate CmPA prevalence in Bahrain and compare clinical characteristics of children with immunoglobulin E(IgE)-and non-IgE-mediated *** This retrospective cohort study examined children with CmPA diagnosed at the pediatric gastroenterology outpatient clinic of the Salmaniya medical Complex,Bahrain,between 2014 and 2022,and assessed CmPA *** presentations,laboratory findings,dietary modifications,and outcomes were compared between children with IgE-mediated and non-IgE-mediated *** variables were compared using Fisher’s exact test or Pearson’sχ2 test,whereas continuous variables were compared using Student’s t-test or the mann-Whitney U *** Of 8332 patients,6022(72.3%)adhered to their *** them,618(10.3%)were suggested of having CmPA and 595(96.3%)were included;CmPA prevalence was 2%.most patients were Bahraini(93.8%)and males(55.3%).Non-IgE-mediated type accounted for 77.3%cases and IgE-mediated type,22.7%.IgE-mediated CmPA presented more in boys(P=0.030),and later in life(5.1 months±4.5 months vs 4.2 months±4.2 months,P=0.016,95%CI:0.08-1.73),had more associated diseases(Pmore cutaneous(P=0.024)and respiratory(P=0.003)manifestations,severe symptoms[rash/dry skin(P=0.031),facial swelling/angioedema(P=0.003),failure to thrive(P=0.013),apparent life-threatening event(Pmediated *** patients were exclusively fed cow milk formula(50.3%).The amino acid-based formula(AAF)was most prescribed(60.5%)with no difference between the two types(P=0.173).Although breastfeeding was recommended to 49.6%,only 8.2%were exclusively ***-mediated CmPA was associated with a longer follow-up duration than non-IgE-mediated CmPA(17.3 months±14.0 mo

关键词： Children milk allergy Immunoglobulin E Breastfeeding Infant formula Bahrain