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Gust response of an elasto-flexible morphing wing using fluid–structure interaction simulations

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Chinese Journal of Aeronautics 2024年第2期37卷 45-57页

作者： Jonathan PFLÜGER christian BREITSAMTER Department of Mechanical Engineering Technical University of MunichGarching 85748Germany

Small and micro unmanned aircraft are the focus of scientific interest due to their wide range of *** often operate in a highly unstable flight environment where the application of new morphing wing technologies offers the opportunity to improve flight *** investigated concept comprises port and starboard adjustable wings,and an adaptive elastoflexible membrane serves as the lifting *** focus is on the benefits of the deforming membrane during the impact of a one-minus-cosine type *** a low Reynolds number of Re=264000,the morphing wing model is investigated numerically by unsteady fluid-structure interaction ***,the numerical results are validated by experimental data from force and moment,flow field,and deformation ***,with the rigid wing as the baseline,the flexible case is investigated,focusing on the advantages of the elastic *** all configurations studied,the maximum amplitude of the lift coefficient under gust load shows good agreement between the experimental and numerical *** the decay of the gust,they differ more the higher the aspect ratio of the *** considering the flow field,the main differences are due to the separation behavior on the upper side of the *** flow reattaches earlier in the experiments than in the simulations,which explains the higher lift values observed in the *** at one intermediate configuration does the lift amplitude of the rigid configuration exceeds that of the flexible by about 12%,with the elastic membrane resulting in a smaller and more uniform peak load,which is also evident in the wing loading and hence in the root bending moment.

关键词： Membrane wing Morphing wing Flexible wing surface Computational fluid dynam-ics Fluid-structure interaction Unsteady inflow condition Gust response

Ray tracing particle image velocimetry-Challenges in the application to a packed bed

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Particuology 2024年第1期84卷 194-208页

作者： Christin Velten Mirko Ebert christian Lessig Katharina Zahringer Lehrstuhl für Strömungsmechanik und Strömungstechnik Otto-von-Guericke-Universität Magdeburg39106MagdeburgGermany Institut für Simulation und Graphik Otto-von-Guericke-Universität Magdeburg39106MagdeburgGermany

Ray tracing Particle Image Velocimetry(RT-PIV)is an optical technique for high resolution velocity measurements in challenging optical systems,such as transparent packed beds,that uses ray tracing to correct for distortions introduced by transparent geometries in the light *** ray tracing based correction is a post processing step applied to the raw PIV particle images before classical PIV *** this study,RT-PIV is performed in the top layer of a body centred cubic(bcc)sphere packing with gaseous flow,where optical access is obtained by the use of transparent N-BK7 glass balls with a diameter of d=40 ***-PIV introduces new experimental and numerical challenges,for example a limited field of view,illumination difficulties,a very large required depth of field and high sensitivity to geometric parameters used in the ray tracing *** challenges and their implications are the main scope and discussed in the present ***,the validation of the ray tracing reconstruction step is presented and examples for the obtained corrected vector fields in a packed bed are *** results show the strength of the method in reconstructing velocity fields behind transparent spheres that would not have been accessible by optical measurement techniques without the ray tracing correction.

关键词： Ray tracing particle image velocimetry(RT-PIV) Transparent spherical particles Packed bed Distortion correction Gas flow

Diabetes and pulmonary infection:how hyperglycaemia shapes the immune system

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Signal Transduction and Targeted Therapy 2024年第4期9卷 1245-1246页

作者： christian Herder Michael Roden Nicolas Venteclef Institute for Clinical Diabetology German Diabetes CenterLeibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf40225DüsseldorfGermany German Center for Diabetes Research(DZD) Partner Düsseldorf85764München-NeuherbergGermany Department of Endocrinology and Diabetology Medical Faculty and University Hospital DüsseldorfHeinrich Heine University Düsseldorf40225DüsseldorfGermany Institut Necker-Enfants Malades(INEM) UniversitéParis CitéINSERM UMR-S1151CNRS UMR-S8253ParisFrance

In a recent study published in Nature,Nobs and colleagues aimed to identify novel mechanisms that may explain why diabetes is associated with an increased susceptibility to viral respiratory *** analyses revealed a central role of lung dendritic cells(DC)which exhibited several functional defects induced by hyperglycaemia and consequently result in impaired antiviral immune responses.

关键词： impaired lung respiratory

Clustering of voltage-gated ion channels as an evolutionary trigger of myelin formation

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Neural Regeneration Research 2024年第8期19卷 1631-1632页

作者： Henrike Ohm Simone Rey christian Klambt Institut fur Neuro-und Verhaltensbiologie MunsterGermany

Neurons carry apical dendrites that perceive information and a basal axon that transmits the computed information towards its to *** axon originates at the axon hillock which is followed by the axon initial ***,action potentials are initiated that are based on millisecond long openings of specific voltagegated sodium and potassium channels that are conserved in all parahoxozoa(Placozoa,Cnidaria,Bilateria)(Li et al.,2015).

关键词： initiated carry potassium

A numerical and experimental comparison of heat transfer in a quasi two-dimensional packed bed

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Particuology 2024年第1期84卷 136-144页

作者： Matthias Tyslik Mirko Ebert Martin Schiemann Siegmar Wirtz christian Lessig Department of Energy Plant Technology Ruhr-University BochumGermany Institute for Simulation and Graphics Otto-von-Guericke-Universität MagdeburgGermany

Heat transfer plays a major role in many industrial processes taking place in packed *** accurate and reliable simulation of the heat exchange between particles is therefore crucial for a reliable operation and to optimize the processes in the *** discrete ordinates method(DOM)provides an established numerical technique to model radiative heat transfer in granular media that offers the possibility to consider the directional dependence of the radiation *** this work,DOM is compared with Monte Carlo ray tracing,which provides an alternative method for heat transfer ***-rically simple configurations are used to investigate the influence of the angular discretization on the accuracy of the results and the computation time in both *** obtained insights are then transferred to a more complex configuration of a quasi two-dimensional test rig consisting of metal rods for which also experimental results are *** results show that both DOM and Monte Carlo ray tracing allow for an accurate simulation of heat transfer in packed *** Carlo ray tracing requires thereby computation times that are surprisingly competitive(although still somewhat slower)compared to DOM and allows for an easier computation of highly accurate reference *** our preliminary comparison to the experimental test rig,Monte Carlo ray tracing also provides the advantage that it can more easily model highly specular materials such as stainless *** methods are comparable for diffuse materials such as magnesium oxide.

关键词： Heat transfer Discrete ordinates method Monte Carlo ray tracing

Melt flow,heat transfer and solidification in a flexible thin slab continuous casting mold with vertical-combined electromagnetic braking

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Journal of Iron and Steel Research International 2024年第2期31卷 401-415页

作者： Lin Xu Ze-feng Han christian Karcher En-gang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang110819LiaoningChina Key Laboratory of Liaoning Province for Clean Combustion Power Generation and Heating Technology Shenyang Institute of EngineeringShenyang110136LiaoningChina Institute of Thermodynamics and Fluid Mechanics Technische Universität IlmenauIlmenau98684Germany

During continuous casting of steel slabs,the application of electromagnetic braking technology(EMBr)provides an effective tool to influence solidification by controlling the pattern of melt flow in the ***,the quality of the final product can be improved considerably.A new electromagnetic braking(EMBr)method,named vertical-combined electromagnetic braking(VC-EMBr),is proposed to be applied to a flexible thin slab casting(FTSC)*** evaluate the beneficial effects of the VC-EMBr,the melt flow,heat transfer,and solidification processes in the FTSC mold are studied by means of numerical *** detail,a Reynolds-averaged Navier–Stokes turbulence model together with an enthalpy-porosity approach was *** numerical findings are compared with respective simulations using the traditional *** results demonstrate that the application of the VC-EMBr contributes significantly to preventing relative slab *** contrast to the Ruler-EMBr,the additional vertical magnetic poles of the VC-EMBr preferentially suppress the direct impact of jet flow on the narrow face of FSTC mold and considerably diminish the level fluctuation near the meniscus *** instance,by applying a magnetic flux density of 0.3 T,the maximum amplitude of meniscus deflection reduces by about 80%.Moreover,the braking effect of the VC-EMBr effectively improves the homogeneity of temperature distribution in the upper recirculation region and increases the solidified shell thickness along the casting *** this basis,the newly proposed VC-EMBr shows a beneficial effect in preventing relative slab defects for FTSC thin slab continuous casting.

关键词： Electromagnetic braking Mold Melt flow Heat transfer Solidification

Embracing digital mindsets to ensure a sustainable future

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 177-179页

作者： Chengjun Li Riqing Yu Wenjing Ning Huan Zhong christian Sonne Institute of Environmental Research at Greater Bay Area Guangzhou UniversityGuangzhou 510000China Department of Biology Center for EnvironmentBiodiversity and ConservationThe University of Texas at TylerTylerTX 75701USA School of Environment Nanjing UniversityNanjing 210000China Environmental and Life Science Program Trent UniversityPeterboroughOntarioK9H 0A1Canada Faculty of Science and Technology Aarhus UniversityRoskildeDenmark 4000The Kingdom of Denmark Sustainability Cluster School of EngineeringUniversity of Petroleum&Energy StudiesDehradunUttarakhand 248001India

The 19th Asian Games astounded global audiences with an opening spectacle that showcased stunning digital fireworks(International Olympic Committee,2021;Zhe,2023).The groundbreaking display was brought to life through virtual reality(VR)and augmented reality(AR)*** sets a pioneering example to replace conventional fireworks in major international events as well as in other large-scale entertainment activities,marking a historic milestone in the pursuit of a sustainable and healthy future.

关键词： Wildlife Climate Change Heavy metals Noise LAN Light pollution

Modelling of the elastoplastic behaviour of the bio-cemented soils using an extended Modified Cam Clay model

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2184-2197页

作者： Xuerui Wang christian B.Silbermann Thomas Nagel Udo Nackenhorst Institute of Mechanics and Computational Mechanics Leibniz UniversitätHannoverAppelstr.9aHannover30167Germany Gesellschaft für Anlagen-und Reaktorsicherheit(GRS)gGmbH Theodor-Heuss-Straße 4Braunschweig38122Germany Geotechnical Institute Technische Universität BergakademieFreibergGustav-Zeuner-Str.1Freiberg09599Germany

An elastoplastic constitutive model based on the Modified Cam Clay(MCC)model is developed to describe the mechanical behaviour of soils cemented via microbially induced calcite precipitation(MICP).It considers the increase of the elastic stiffness,the change of the yield surface due to MICP cementation and the degradation of calcium carbonate bonds during ***,to capture the typical contraction-dilation transition in MICP soils,the original volumetric hardening rule in the MCC model is modified to a combined deviatoric and volumetric hardening *** model could reproduce a series of drained triaxial tests on MICP-treated soils with different calcium carbonate ***,we carry out a parametric study and observe numerical instability in some *** combination with an analytical analysis,our numerical modelling has identified the benefits and limitations of using MCCbased models in the simulation of MICP-cemented soils,leading to suggestions for further model development.

关键词： Microbially induced calcite precipitation(MICP) Elastoplasticity Modified cam clay(MCC) OpenGeoSys MFront Contraction-dilation transition

Medical management of urolithiasis: Great efforts and limited progress

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Asian Journal of Urology 2024年第2期11卷 149-155页

作者： Victoria Jahrreiss christian Seitz Fahad Quhal Department of Urology Comprehensive Cancer CenterMedical University of ViennaViennaAustria Department of Urology King Fahad Specialist HospitalDammamSaudi Arabia

Objective:To provide a comprehensive review on the existing literature on medical management of ***:A thorough literature review was performed using Medline,PubMed/PMC,Embase,and the Cochrane Database of Systematic Reviews up to December 2022 to identify publications on the medical management of *** that assessed dietary and pharmacologic management of urolithiasis were reviewed;studies on medical expulsive therapy were not included in this ***:Medical management of urolithiasis ranges from the prophylactic management of kidney stone disease to dissolution *** most treatment concepts have been long established,large randomized controlled trials are *** modification and increased fluid intake remain cornerstones in the conservative management of urolithiasis.A major limitation for medical management of urolithiasis is poor patient ***:Medical management of urolithiasis is more important in patients with recurrent urolithiasis and patients with metabolic abnormalities putting them at higher risk of developing *** medical management can be effective in limiting stone recurrence,medical interventions often fail due to poor compliance.

关键词： Medicalmanagement Medical therapy Urolithiasis Kidneystonedisease