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Discrete particle modeling of granular temperature distribution in a bubbling fluidized bed

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Particuology 2012年第4期10卷 428-437页

作者： Yurong He Tianyu Wang niels deen Martin van Sint Annaland Hans Kuipers Dongsheng Wen Department of Power Engineering College of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Department of Chemical Engineering and Chemistry Eindhoven University of TechnologyPO Box 5135600 MB EindhovenThe Netherlands School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon El 4NSUK

The discrete hard sphere particle model （DPM） is applied in this work to study numerically the distribu- tions of particle and bubble granular temperatures in a bubbling fluidized bed. The dimensions of the bed and other parameters are set to correspond to those of Miuller et al（2008）. Various drag models and oper- ational parameters are investigated to find their influence on particle and bubble granular temperatures. Various inlet superficial gas velocities are used in this work to obtain their effect on flow characteristics. It is found that the superficial gas velocity has the most important effect on granular temperatures including bubble granular temperature, particle translational granular temperature and particle rotational granular temperature. The drag force model affects more seriously the large scale variables such as the bubble gran- ular temperature. Restitution coefficient influences all granular temperatures to some degree. Simulation results are compared with experimental results by Muller et al. （2008） showing reasonable agreement.

关键词： Bubbling fluidized bedDiscrete hard sphere modelParticle and bubble granular temperature

Influence of rolling friction on single spout fluidized bed simulation

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Particuology 2012年第5期10卷 582-591页

作者： Christoph Goniva Christoph Kloss niels G. deen Johannes A.M.Kuipers Stefan Pirker Christian-Doppler Laboratory on Particulate Flow Modelling Johannes Kepler UniversityLinz Austria DCS Computing GmbH Linz Austria Christian-Doppler Laboratory on Particulate Flow Modelling Johannes Kepler UniversityLinz Austria Department of Chemical Engineering and Chemistry Eindhoven University of TechnologyEindhovenThe Netherlands Department of Chemical Engineering and Chemistry Eindhoven University of TechnologyEindhovenThe Netherlands Christian-Doppler Laboratory on Particulate Flow Modelling Johannes Kepler UniversityLinzAustria Institute of Fluid Mechanics and Heat Transfer Johannes Kepler UniversityLinzAustria

In this paper we study the effect of rolling friction on the dynamics in a single spout fluidized bed using Discrete Element Method （DEM） coupled to Computational Fluid Dynamics （CFD）. In a first step we neglect rolling friction and show that the results delivered by the open source CFD-DEM framework applied in this study agree with previous simulations documented in literature. In a second step we include a rolling friction sub-model in order to investigate the effect of particle non-sphericity. The influence of particle-particle as well as particle-wall rolling friction on the flow in single spout fluidized bed is studied separately. Adequate rolling friction model parameters are obtained using first principle DEM simulations and data from literature. Finally, we demonstrate the importance of correct modelling of rolling friction for coupled CFD-DEM simulations of spout fluidized beds. We show that simulation results can be improved significantly when applying a rolling friction model, and that experimental data from literature obtained with Positron Emission Particle Trackin~ fPEPT） technique can be satisfactorily reoroduced.

关键词： CFD-DEMOpen sourceRolling frictionSpout fluidized bedNon-sphericity

Oncostatin M:a love-hate relationship in neuroinflammation

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Neural Regeneration Research 2024年第12期19卷 2571-2572页

作者： Doryssa Hermans niels Hellings Bieke Broux University MS Center Campus DiepenbeekDiepenbeekBelgium Neuro-Immune Connections and Repair Lab Department of Immunology and InfectionBiomedical Research InstituteHasselt UniversityDiepenbeekBelgium

Oncostatin M and multiple sclerosis:Every 5minutes,someone in the world is diagnosed with multiple sclerosis(MS),a chronic inflammatory and degenerative disease of the central nervous system(CNS).MS appears in unpredictable episodes of symptoms,which are highly patient-dependent,but often include visual impairment,muscle weakness/spasms,fatigue,cognitive difficulties,and *** sexual dysfunction.

关键词： visual bladder someone

Semi-analytical calculation model for friction of polymers on the example of POM|PE-UHMW and steel|PE-UHMW

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Friction 2024年第10期12卷 2355-2369页

作者： André BERGMANN Jens SUMPF niels DALLINGER Martin MONEKE Markus GOLDER Professorship of Conveying Engineering and Materials Handling Chemnitz University of TechnologySachsen 09126Germany Institute of Plastics Engineering Darmstadt University of Applied SciencesDarmstadt 64295Germany

In this paper,a semi-analytical calculation model for the coefficient of friction(COF)of single spherical protrusions is *** allows the prediction of the deformative friction part(μ_(def))and adhesive friction part(μ_(def))of the friction pairings steel|polyethylene with ultra-high molecular weight(PE-UHMW)and polyoxymethylene(POM)|*** experimental studies included unlubricated friction tests,which served to determine the total COF(μ_(def)),as well as tests being lubricated with silicone oil,from whichμ_(def)is *** on the verification tests,it could be shown that both states of lubrication result in the same deformation and that the relationship between the rear angle(w)andμ_(def)postulated in the calculation model is ***,friction tests with segmented spheres were carried out,which allow a specific variation of *** can be concluded that for both pairings theμ_(def)is generally of minor significance(approx.1/3μ_(tot))and the influence of theμ_(adh)predominates(approx.2/3μ_(tot))the friction *** themtot decreases with increasing contact pressure especially in the low pressure range and depends on the form of motion(continuous and discontinuous).

关键词： tribology friction polymers model contact polyoxymethylene(POM) polyethylene with ultra-high molecular weight(PE-UHMW)

用于振动模态可操纵性的克拉尼图形拓扑优化设计

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Acta Mechanica Sinica 2024年第4期40卷 172-184页

作者：薛亮文桂林 Fengwen Wang niels LPedersen School of Mechanical Engineering Yanshan UniversityQinhuangdao066004China Department of Civil and Mechanical Engineering Solid MechanicsTechnical University of DenmarkKgs.Lyngby2800Denmark Body Hunan UniversityChangsha410082China

经典克拉尼图形(Chladni patterns,CP)是特征向量的视觉表示,在振动分析、乐器设计、粒子操纵和分离等领域中具有广泛的应用.均质结构通常会表现出高度规则化的CP,这限制它们的应用场景.因此,实现面向应用来逆向设计结构的CP是非常重要... 详细信息

经典克拉尼图形(Chladni patterns,CP)是特征向量的视觉表示,在振动分析、乐器设计、粒子操纵和分离等领域中具有广泛的应用.均质结构通常会表现出高度规则化的CP,这限制它们的应用场景.因此,实现面向应用来逆向设计结构的CP是非常重要的,而这可以通过使用拓扑优化来实现CP的逆向设计.本研究提出了一种使用基于密度的拓扑优化算法来设计结构CP的方法.优化列式中,给出了描述图形的指标函数,并以最小化特征向量和目标CP之间的误差构建了优化目标.数值结果表明,所提出的方法可以为指定的单阶或多阶CP生成新颖的材料分布.这表明了本文所提出的方法能够实现CP的精确定制设计,进一步为面向应用的需求提供了更多选择.

关键词：定制设计面向应用逆向设计指标函数特征向量拓扑优化可操纵性振动模态

Physiological and perceptual responses to sprint interval exercise using arm versus leg cycling ergometry

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Sports Medicine and Health Science 2024年第4期6卷 385-393页

作者： Todd A.Astorino Shealin Pierce Madisen B.Piva Richard S.Metcalfe niels B.J.Vollaard Department of Kinesiology CSU—San MarcosSan MarcosCAUSA Applied Sports TechnologyExercise and Medicine(A-STEM)Research CenterSwansea UniversitySwanseaUK Faculty of Health Sciences and Sport University of StirlingStirlingUK

Increases in power output and maximal oxygen consumption(V_O2max)occur in response to sprint interval exercise(SIE),but common use of“all-out”intensities presents a barrier for many ***,lower-body SIE is not feasible for all *** compared physiological and perceptual responses to supramaximal,but“nonall-out”SIE between leg and arm cycling ***-four active adults(mean±SD age:[25±7]y;cycling VO_(2)max:[39±7]mL·kg^(-1)·min^(-1))performed incremental exercise using leg(LCE)and arm cycle ergometry(ACE)to determine VO_(2)max and maximal work capacity(Wmax).Subsequently,they performed four 20 s bouts of SIE at 130% Wmax on the LCE or ACE at cadence=120-130 rev/min,with 2 min recovery between *** exchange data,heart rate(HR),blood lactate concentration(BLa),rating of perceived exertion(RPE),and affective valence were *** showed significantly lower(p0.42),and lowest affective valence recorded(2.0±1.8)was considered“good to fairly good”.Data show that non“all-out”ACE elicits lower absolute but higher relative HR and VO_(2) compared to *** aversive perceptual responses could make this non-all-out modality feasible for inactive adults.

关键词： High intensity interval training Upper body exercise Peak power output Oxygen uptake Blood lactate concentration

Investigation of Hexavalent Chromium Reduction in Strong Saline and Acidic Nitro-Phosphate Solutions

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Journal of Analytical Sciences, Methods and Instrumentation 2024年第1期14卷 1-13页

作者： Deniz Avsar niels Højmark Andersen Dag Øistein Eriksen Jon Petter Omtvedt Department of Chemistry University of Oslo Oslo Norway

Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various types of hazardous elements are required. Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge. Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process. The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra. The results show that Cr (VI) is not stable in strong nitric acid solutions. Reduction of Cr (VI) species decreased with decreasing temperature, NO2 concentration, ionic strength and absence of light. These findings support the proposed reduction reaction:The reduction rate was observed proportional to the nitric acid decomposition: .

关键词： Nitro-Phosphate Fertilizers Chromium (VI) Reduction Chromium Speciation Ultraviolet-Visible Spectroscopy

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慢性肾脏病患者患病体验的质性研究

军事护理 2024年第8期41卷 74-77页

作者：申红霞黎敏仪赖美琦严斯静 Rianne van der Kleij niels Chavannes 广州医科大学护理学院广东广州510182 莱顿大学医学中心荷兰莱顿2300 RC

目的了解慢性肾脏病(chronic kidney disease,CKD)患者的患病体验,为构建个性化干预提供依据。方法采用现象学研究法,以目的抽样结合滚雪球抽样方法选取2021年10月至2022年7月河南省某三级甲等医院肾内科18例慢性肾脏病患者进行半结构... 详细信息

目的了解慢性肾脏病(chronic kidney disease,CKD)患者的患病体验,为构建个性化干预提供依据。方法采用现象学研究法,以目的抽样结合滚雪球抽样方法选取2021年10月至2022年7月河南省某三级甲等医院肾内科18例慢性肾脏病患者进行半结构式深度访谈,通过框架分析法和***软件进行资料分析。结果可归纳为5个主题:疾病确诊经历、症状困扰与日常生活改变、经济负担沉重、社会行为退缩和社交隔离和多样化支持需求。结论CKD患者在疾病过程中存在多维度问题和需求,医护人员应重视完善基层防治、推进健康科普,探索合适的心理干预策略以及运用远程技术进行CKD患者的延续性支持,提升其生活质量。

关键词：慢性肾脏病体验照护需求质性研究

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利用择形分子筛异构化亚甲基二苯胺

Chinese Journal of Catalysis 2024年第7期62卷 124-130页

作者： Sam Van Minnebruggen Ka Yan Cheung Trees De Baerdemaeker niels Van Velthoven Matthias Degelin Galahad O’Rourke Hiroto Toyoda Andree Iemhoff Imke Muller Andrei-Nicolae Parvulescu Torsten Mattke Jens Ferbitz 吴勤明肖丰收 Toshiyuki Yokoi Nils Bottke Dirk De Vos 巴斯夫股份有限公司膜分离、吸附、催化和光谱学可持续解决方案中心(cMACS) 比利时巴斯夫股份有限公司研究组德国东京工业大学纳米空间催化研究所横滨日本浙江大学化学系浙江杭州310028

亚甲基二苯胺(MDA)被广泛用作生产聚氨酯和聚异氰脲酸酯的中间体.然而,当前MDA的生产工艺在控制(4,4’/(2,4’+2,2’))异构体比例方面还存在局限.其中,4,4’-MDA被认为是最有价值的异构体.尽管2,4'-MDA在市场上也有一定的需求,但如果能... 详细信息

亚甲基二苯胺(MDA)被广泛用作生产聚氨酯和聚异氰脲酸酯的中间体.然而,当前MDA的生产工艺在控制(4,4’/(2,4’+2,2’))异构体比例方面还存在局限.其中,4,4’-MDA被认为是最有价值的异构体.尽管2,4'-MDA在市场上也有一定的需求,但如果能将其有效地转化为4,4'-MDA,将能显著提升其附加值.本文在使用苯胺的条件下,利用β分子筛等催化剂,通过双分子机制,可以选择性地将2,4'-MDA异构化为4,4'-MDA.尽管实验显示,多种酸性沸石具有较高的异构化活性,但MCM-68(具有MSE拓扑结构)的催化性能尤为出色,它不仅展现出高异构化活性,而且具有很好的选择性.MCM-68主要催化2,4'-MDA异构化为4,4'-MDA,而2,2'-MDA和低聚物的形成则可以忽略不计.本文还深入探讨了该择形作用的原因,并详细研究了酸位置在MSE分子筛孔道限制中的关键作用.

关键词：铝分布多相催化异构化亚甲基二苯胺聚氨酯择形