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Analysis of non-symmetrical flapping airfoils

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Acta Mechanica Sinica 2009年第4期25卷 433-450页

作者： w.b.tay K.b.Lim Department of Mechanical Engineering National University of Singapore

Simulations have been done to assess the lift, thrust and propulsive efficiency of different types of non-symmetrical airfoils under different flapping configurations. The variables involved are reduced frequency, Strouhal number, pitch amplitude and phase angle. In order to analyze the variables more efficiently, the design of experiments using the response surface methodology is applied. Results show that both the variables and shape of the airfoil have a profound effect on the lift, thrust, and efficiency. by using non- symmetrical airfoils, average lift coefficient as high as 2.23 can be obtained. The average thrust coefficient and efficiency also reach high values of 2.53 and 0.61, respectively. The lift production is highly dependent on the airfoil＇s shape while thrust production is influenced more heavily by the variables. Efficiency falls somewhere in between. Two-factor interac- tions are found to exist among the variables. This shows that it is not sufficient to analyze each variable individually. Vorticity diagrams are analyzed to explain the results obtained. Overall, the S1020 airfoil is able to provide relatively good efficiency and at the same time generate high thrust and lift force. These results aid in the design of a better ornithopter＇s wing.

关键词： Flapping Non-symmetrical Design ofexperiments Ornithopter Airfoil

Effect of Different Types of wing-wing Interactions in Flapping MAVs

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Journal of bionic Engineering 2017年第1期14卷 60-74页

作者： wee beng tay Temasek Laboratories National University of Singapore 5A Engineering Drive 1 117411 Singapore

wing-wing Interaction （wwI）, such as the Clap and Fling Motion （CFM）, occurs when two wings are flapping close together, improving performance. we intend to design a hovering Flapping Micro Aerial Vehicle （FMAV） which makes use of wwI. we investigate the effects of flexibility, kinematic motions, and two- to six-wing flapping configurations on the FMAV through numerical simulations. Results show that a rigid spanwise and flexible chordwise wing produces the highest lift with minimum power. The smoothly varying sinusoidal motion, which is visually similar to the CFM, produces similar lift in comparison to the CFM, while having lower peak power requirement. Lastly, lift produced by each wing of the two-, four-, six-wing configurations is approximately equal. Hence more wings generate higher total lift force, but at the expense of higher drag and power requirement. These results will be beneficial in the understanding of the underlying aerodynamics of wwI, and in improving the performance of our FMAV.

关键词： flapping wings MAV immersed boundary methods clap and fling

A novel method for clustering cellular data to improve classification

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Neural Regeneration Research 2025年第9期20卷 2697-2705页

作者： Diek w.wheeler Giorgio A.Ascoli Center for Neural Informatics Structures&PlasticityKrasnow Institute for Advanced Study bioengineering Department Volgenau School of Engineering George Mason University FairfaxVAUSA

Many fields,such as neuroscience,are experiencing the vast prolife ration of cellular data,underscoring the need fo r organizing and interpreting large datasets.A popular approach partitions data into manageable subsets via hierarchical clustering,but objective methods to determine the appropriate classification granularity are *** recently introduced a technique to systematically identify when to stop subdividing clusters based on the fundamental principle that cells must differ more between than within *** we present the corresponding protocol to classify cellular datasets by combining datadriven unsupervised hierarchical clustering with statistical *** general-purpose functions are applicable to any cellular dataset that can be organized as two-dimensional matrices of numerical values,including molecula r,physiological,and anatomical *** demonstrate the protocol using cellular data from the Janelia MouseLight project to chara cterize morphological aspects of neurons.

关键词： cellular data clustering dendrogram data classification Levene's one-tailed statistical test unsupervised hierarchical clustering

Flow field generated by a dielectric barrier discharge plasma actuator in quiescent air at initiation stage

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Chinese Journal of Aeronautics 2021年第3期34卷 13-24页

作者： Xin ZHANG Y.D.CUI Chien Ming Jonathan tay b.C.KHOO State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China National University of Singapore Singapore 119260Singapore

A single Dielectric barrier Discharge(DbD) plasma actuator driven by Alternating Current(AC) power, capable of inducing a starting vortex and a wall jet in quiescent air, is suited for low-Reynolds-number flow control. However, the starting vortex and the wall jet are usually observed after the plasma actuator has been operated for dozens of and hundreds of cycles of the voltage, respectively. The detail of the induced flow field at the initiation stage of the plasma actuator has rarely been addressed. At the initiation stage, a thin jet that provides the impetus for the entrainment of the induced flow at the beginning of the plasma actuation is first observed by using a high-accuracy phase-lock Schlieren technique and a high-speed Particle Image Velocimetry(PIV) system. This is the initial form of the momentum transfer from the plasma to the ***, an arched type jet is created by the plasma actuator. In addition, the whole development process of the induced flow field from the starting point of the thin jet to the quasi-steady stage of wall jet is presented for providing a comprehensive understanding of the plasma actuator and proposing a relevant enhancement of the numerical simulation model.

关键词： Dielectric barrier discharge Particle image velocimetry Plasma actuator Schlieren technique wall jet

Genistein:a possible solution for the treatment of Alzheimer’s disease

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Neural Regeneration Research 2025年第10期20卷 2903-2905页

作者： Karolina Pierzynowska bartosz Karaszewski Grzegorz węgrzyn Department of Molecular biology University of GdanskGdanskPoland Gdansk Polandand Department of Adult NeurologyFaculty of MedicineMedical University of GdanskGdanskPoland

Neurodegenerative diseases are defined as disorders resulting from the slow and progressive loss of function and eventual death of neural cells that result from the primary pathology of nervous *** can lead to severe nervous system dysfunction,eventually affecting multiple organs and *** hundred neurodegenerative diseases have been described,and owing to their prevalence,severity.

关键词： organs Alzheimer death

Glia-to-neuron reprogramming to the rescue?

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Neural Regeneration Research 2025年第5期20卷 1395-1396页

作者： Jack w.Hickmott Cindi M.Morshead Department of Surgery University of TorontoTorontoONCanada Donnelly Centre for Cellular and biomolecular Research TorontoONCanada Institute of biomedical Engineering University of TorontoTorontoONCanada The KITE Research Institute Toronto Rehabilitation InstituteUniversity Health NetworkTorontoONCanada

Over the last two decades,the dogma that cell fate is immutable has been increasingly challenged,with important implications for regenerative *** brea kth rough discovery that induced pluripotent stem cells could be generated from adult mouse fibroblasts is powerful proof that cell fate can be *** exciting extension of the discovery of cell fate impermanence is the direct cellular reprogram ming hypothesis-that terminally differentiated cells can be reprogrammed into other adult cell fates without first passing through a stem cell state.

关键词： programming passing proof

Neuroinflammation revisited through the microglial lens

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Neural Regeneration Research 2025年第7期20卷 1989-1990页

作者： Renato Socodato João b.Relvas Institute of Research and Innovation in Health(i3S)and Institute for Molecular and Cell biology(IbMC) University of PortoPortoPortugal Department of biomedicine Faculty of Medicine of the University of Porto(FMUP)PortoPortugal

Neuroimmunology is emerging as a pivotal field,shedding light on the intricate dialogues between the central nervous system(CNS)and the immune *** exploration is particularly significant in understanding microglia,the CNS’s innate immune cells,beyond the conventional conflation of“neuroinflammation”and“microglial activation.”This conflation has clouded the true complexity of these processes,potentially stalling scientific progress and the development of new *** challenge the long-standing perspectives that have oversimplified these interactions,advocating for a deeper exploration of the dynamic relationship between neuroinflammation and microglial *** dissecting specific molecular pathways,we aim to illuminate their elaborate roles in neuroinflammatory responses,especially in the context of Alzheimer’s disease(AD).Here,neuroinflammation is not merely a passive observer or a direct antagonist but a complex agent in the disease’s *** article calls for a significant paradigm shift towards an integrative,multi-omics approach to *** such a comprehensive framework is crucial for advancing our understanding of neuroinflammatory conditions and paving the way for targeted therapeutic strategies for brain diseases.

关键词： inflammation simplified activation

Unconventional topological phase transition in non-symmorphic material KHgX(X=As,Sb,bi)

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npj Computational Materials 2019年第1期5卷 599-605页

作者： Chin-Shen Kuo tay-Rong Chang Su-Yang Xu Horng-tay Jeng Department of Physics National Tsing Hua UniversityHsinchu 30013Taiwan Department of Physics National Cheng Kung UniversityTainan 701Taiwan Center for Quantum Frontiers of Research&Technology(QFort) Tainan 701Taiwan Department of Physics Massachusetts Institute of TechnologyCambridgeMA 02139USA Physics Division National Center for Theoretical SciencesHsinchu 30013Taiwan Institute of Physics Academia SinicaTaipei 11529Taiwan

Traditionally topological phase transition describes an evolution from topological trivial to topological nontrivial *** from the non-symmorphic crystalline symmetry,we propose in this work an unconventional topological phase transition scheme between two topological nontrivial insulating states mediated by a Dirac gapless state,differing from the traditional topological phase *** KHgX(X=As,Sb,bi)family is the first experimentally realized topological non-symmorphic crystalline insulator(TNCI),where the topological surface states are characterized by the Mobius-twisted *** on first-principles calculations,we present a topological insulator–metal transition from TNCI into a Dirac semimetal(DSM)via applying an external pressure on *** find an unusual mirror Chern number C_(m)=−3 for the DSM phase of KHgX in the non-symmorphic crystal structure,which is topologically distinct from the traditional DSM such as Na_(3)bi and Cd_(3)As_(2).Furthermore,we predict a new TNCI phase in KHgX via symmetry *** topological surface states in this new TNCI phase display zigzag connectivity,different from the unstressed *** results offer a comprehensive study for understanding how the topological surface states evolve from a quantum phase transition in non-symmorphic system.

关键词： topological transition phase

Determining the road traffic accident hotspots using GIS-based temporal-spatial statistical analytic techniques in Hanoi,Vietnam

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Geo-Spatial Information Science 2020年第2期23卷 153-164页

作者： Khanh Giang Le Pei Liu Liang-tay Lin College of Construction and Development Feng Chia UniversityTaichungTaiwanChina Faculty of Civil Engineering University of Transport and CommunicationsHanoiVietnam

This study applied GIS-based statistical analytic techniques to investigate the influence of accident Severity Index(SI)on temporal-spatial patterns of accident hotspots related to the specific time intervals of day and *** Traffic Accident(RTA)data in 3 years(2015-2017)in Hanoi,Vietnam were used to analyze and test this ***,the RTA data were divided into four seasons in accordance with Hanoi's weather conditions and the time intervals such as the daytime,nighttime,or peak ***,the Kernel Density Estimation(KDE)method was applied to analyze hotspots according to the time intervals and ***,the results were presented by using the comap *** study considered both analyses with and without *** accident SI measures the seriousness of an *** approach method is to give higher weights to the more serious accidents,but not with the extremely high values calculated on a direct rate to the accident *** results showed that both analyses determined the relatively similar hotspots,but the rankings of some hotspots were quite different due to the integration of *** is better to take into account SI in determining RTA hotspots because the gained results are more precise and the rankings of hotspots are more *** there,the traffic authorities can easily understand the causes behind each accident and provide reasonable solutions to solve the most dangerous hotspots in case of limited budget and resources *** is also the first study about this issue in Vietnam,so the contribution of the article will help the traffic authorities easily solve this problem not only in Hanoi but also in other cities.

关键词： Road Traffic Accident(RTA) hotspot GIS temporal-spatial analysis Kernel Density Estimation(KDE) Severity Index(SI)