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Aerodynamics of a Tandem-Bladed Axial Compressor Rotor under Circumferential Distortion at Different Rotational Speeds

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Journal of Thermal Science 2024年第4期33卷 1340-1356页

作者： Amit KUMAR Jerry T.john A.M.PRADEEP R.A.DAKKERMANS Dragan KOZULOVIC Department of Aerospace Engineering Indian Institute of Technology BombayMumbai400076India Department of Automotive and Aeronautical Engineering Hamburg University of Applied Sciences20099HamburgGermany Institute of Jet Propulsion Bundeswehr University Munich85577NeubibergGermany

For most aircraft engines,inflow distortion is *** distortion is known to degrade the aerodynamic performance and stable operating limits of a *** rotor configuration is an arrangement that effectively controls the growth of the boundary layer over the suction surface of the ***,a higher total pressure rise can be achieved through this unconventional design approach involving the splitting of the blade into forward and aft *** is expected that the effect of inlet flow distortion would be more severe for a tandem-rotor design due to the greater flow turning inherent in such ***,this aspect needs to be thoroughly *** present study discusses the effect of circumferential distortion on the tandem-rotor at different rotational ***-annulus RANS simulations using ANSYS CFX are used in the present *** performance of the rotor at a particular flow coefficient and different rotational speeds is *** total pressure and efficiency are observed to drop at lower mass flow rates under the influence of circumferential *** loss region in each blade passage is mainly associated with the blade wake,tip leakage vortex,secondary flow,and boundary ***,their contribution varies from passage to passage,particularly in the distorted *** the lower span,the wake width is found to be higher than that at a higher *** to the redistribution of the mass flow,the circumferential extent reduces at a higher *** the undistorted sector,the strength of the tip leakage vortex is significantly higher at the design rotational speed than at lower *** distortion near the tip region promotes an early vortex breakdown even at the design operating *** adversely affects the total pressure,efficiency,and stall *** clean flow conditions,this phenomenon is only observed near the stall *** the design operating condition,the breakdown of the forward rotor tip l

关键词： tandem rotor circumferential distortion loss tip leakage vortex vortex breakdown diffusion factor aerodynamics of compressor blade

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Robust Machine Learning Mapping of sEMG Signals to Future Actuator Commands in Biomechatronic Devices

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Journal of Bionic Engineering 2024年第1期21卷 270-287页

作者： Ali Nasr Sydney Bell Rachel L.Whittaker Clark R.Dickerson john McPhee Systems Design Engineering University of WaterlooWaterloo N2L 3G1Canada Kinesiology and Health Sciences University of WaterlooWaterloo N2L3G3Canada

A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for high-level myoelectric-based hierarchical control is proposed.A Recurrent Neural Network(RNN)was trained using output data,initially obtained from offline optimization of the biomechatronic(human–robot)device and shifted by the prediction *** input of the RNN consisted of interrupted sEMG signals(to mimic signal disconnections)and previous kinematic signals of the assistive *** RNN with a 0.1-s prediction horizon could predict the control-oriented joint angle and assistive torque with 92%and 86.5%regression accuracy,respectively,for the test *** proposed approach permits a fast,predictive,and direct estimation of control-oriented signals instead of an iterative process that optimizes assistive torque in the inverse dynamic simulation of a multibody human–robot *** with these interrupted input signals significantly improves the regression accuracy in the case of sEMG signal *** Robust Predictive Control-oriented Machine Learning(Robust-MuscleNET)model can support volitional high-level myoelectric-based control of biomechatronic devices,such as exoskeletons,prostheses,and assistive/resistive *** work should study the application to prosthesis control as well as the repeatability of the high-level controller with electrode *** low-level hierarchical controller that manages the human–robot interaction,the assistance/resistance strategy,and the actuator coordination should also be studied.

关键词： Myoelectric-based control-Surface electromyography Machine learning Multibody system dynamics Exoskeleton Bionic

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The first record of a Konservat-Lagerstätten in which early post-settlement stages of fossil archaeobalanids(Cirripedia:Balanomorpha)are preserved

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Integrative Zoology 2024年第2期19卷 200-223页

作者： Tomáš KOCÍ Rok GAŠPARIC john BUCKERIDGE Martina KOCOVÁ VESELSKÁ Aleš ŠOSTER Ivancická581 PragueCzech Republic Palaeontological Department Natural History MuseumNational MuseumPragueCzech Republic Oertijdmuseum Bosscheweg 80Boxtel5293 WBThe Netherlands Institute for Palaeobiology and Evolution Novi TrgKamnikSlovenia Earth and Oceanic Systems Group RMIT UniversityMelbourneAustralia Museums Victoria CarltonVictoriaAustralia Department of Paleobiology and Paleoecology Institute of Geology of the Czech Academy of SciencesPragueCzech Republic Institute of Geology and Palaeontology Charles UniversityPragueCzech Republic Faculty of Natural Sciences and Engineering University of LjubljanaLjubljanaSlovenia

A diverse sessile barnacle fauna from a Miocene shallow-water deposit at Dolnja Stara vas in Slovenia is *** includes the first descriptions of early post settlement juveniles of Actinobalanus sloveniensis attached to mangrove *** represent three distinct growth phases,the earliest being interpreted as being less than 24 h post settlement,the others being 1 to 2 days post *** assessment of their taphonomy is *** adult balanomorphs are attached to a variety of organic substrates,including mangrove leaves and branches,fragments of the conifers?Taxodioxylon,Carapoxylon,pine cones,molluscs,and cetacean *** barnacles include ***,Amphibalanus venustus,and Perforatus perforatus—many with opercula retained within the *** retains some of the original shell *** is the second record of barnacle–plant associations from the Central Paratethys from Kamnik and *** paleoecology and paleogeography of the site are discussed.

关键词： acorn barnacles barnacle metamorphosis epibiont paleoecology taxonomy

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A new species of Discostella guiyangensis ***.(Bacillariophyta,Stephanodiscales)from Guiyang,China:morphology and phylogeny

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Journal of Oceanology and Limnology 2024年第4期42卷 1312-1324页

作者： Yandan XIANG Fangru NAN Xudong LIU Shulian XIE john Patrick KOCIOLEK Qi LIU School of Life Science Shanxi UniversityTaiyuan 030006China Department of Ecology and Evolutionary Biology and Museum of Natural History University of ColoradoBoulder CO 80309USA

We describe a new species of Discostella from Guiyang based on light and scanning electron microscopic observations,as well as molecular *** species is morphologically distinguished from other species by a relatively smooth and slightly recessed central area with marginal striae of unequal lengths forked near the *** fultoportulae and a single rimoportula are situated between every two costae or on the *** morphological characters and the concatenated data of rbc L and SSU rDNA indicate that Discostella guiyangensis is a unique and new *** to divergence time estimation analysis,Discostella guiyangensis is the oldest species among the Discostella species sequenced *** addition,we complement molecular data of Discostella asterocostata and Discostella stelligera.

关键词： Discostella morphology molecular analysis divergence time estimation new species

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A holistic approach to improving safety for battery energy storage systems

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Journal of Energy Chemistry 2024年第5期92卷 422-439页

作者： James Close Jonathan E.Barnard Y.M.john Chew Semali Perera Department of Chemical Engineering Centre for DigitalManufacturing&DesignUniversity of BathBath BA27AYUK ioMosaic International Limited 16-18 Queen SquareBath BA12HNUK

The integration of battery energy storage systems(BESS)throughout our energy chain poses concerns regarding safety,especially since batteries have high energy density and numerous BESS failure events have *** spread adoption will only increase the prevalence of these failure events unless there is a step change in the management and design of *** understand the causes of failure,the main challenges of BESS safety are *** consequences and failure events are discussed,including specific focus on the chain of events causing thermal runaway,and a case study of a BESS explosion in Surprise Arizona is *** on the technology and past events,a paradigm shift is required to improve BESS *** this review,a holistic approach is *** combines currently adopted approaches including battery cell testing,lumped cell mathematical modelling,and calorimetry,alongside additional measures taken to ensure BESS safety including the requirement for computational fluid dynamics and kinetic modelling,assessment of installation level testing of the full BESS system and not simply a single cell battery test,hazard and layers of protection analysis,gas chromatography,and composition *** holistic approach proposed in this study aims to address challenges of BESS safety and form the basis of a paradigm shift in the safety management and design of these systems.

关键词： Energy storagesystems Process safety Battery safety Thermal safety

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Exploring the Reasons for Selfie-Taking and Selfie-Posting on Social Media with Its Effect on Psychological and Social Lives:A Study among Indian Youths

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International Journal of Mental Health Promotion 2024年第5期26卷 389-398页

作者： Divya P.Vijayan Tokani Ghuhato Eslavath Rajkumar Allen Joshua George Romate john john Abraham Department of Psychology Central University of KarnatakaKalaburagi585367India Department of Liberal Arts Indian Institute of Technology BhilaiChhattisgarh491002India Liberal Arts&Sciences Indian Institute of Management RanchiJharkhand834001India Department of Family Medicine/Geriatrics St.John’s National Academy of Health SciencesBangalore560034India

‘Selfie’taking was introduced to the common people by smartphones and has become a common practice across the globe in no *** technological advancement and the popularity of smartphones,selfie-taking has grown rapidly within a short *** light of the new trend set by the generation,this study aimed to explore reasons for selfie-taking and selfie-posting on social media and their effects on the social and psychological lives of young adults.A purposive sampling method was adopted to select 20 Indian citizens,between 18 and 24 *** data were collected through semi-structured interviews and analysed using thematic ***-taking and posting on social media give positive feelings,and it acts as a mood modifier dependent mostly on the favourability and feedback about the post which in turn affects emotions and self-satisfaction.

关键词： Selfie social media social networking sites obsessive selfie-taking Indian youth

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Damage evolution of rock-encased-backfill structure under stepwise cyclic triaxial loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 597-615页

作者： Xin Yu Yuye Tan Weidong Song john Kemeny Shengwen Qi Bowen Zheng Songfeng Guo Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100089China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing100089China University of Chinese Academy of Sciences Beijing100049China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of China) University of Science and Technology BeijingBeijing100083China Department of Mining and Geological Engineering University of ArizonaTucsonAZ86721USA

Rock-encased-backfill(RB)structures are common in underground mining,for example in the cut-andfill and stoping *** understand the effects of cyclic excavation and blasting activities on the damage of these RB structures,a series of triaxial stepwise-increasing-amplitude cyclic loading experiments was conducted with cylindrical RB specimens(rock on outside,backfill on inside)with different volume fractions of rock(VF=0.48,0.61,0.73,and 0.84),confining pressures(0,6,9,and 12 MPa),and cyclic loading rates(200,300,400,and 500 N/s).The damage evolution and meso-crack formation during the cyclic tests were analyzed with results from stress-strain hysteresis loops,acoustic emission events,and post-failure X-ray 3D fracture *** results showed significant differences between cyclic and monotonic loadings of RB specimens,particularly with regard to the generation of shear microcracks,the development of stress memory and strain hardening,and the contact forces and associated friction that develops along the rock-backfill *** important finding is that as a function of the number of cycles,the elastic strain increases linearly and the dissipated energy increases ***,compared with monotonic loading,the cyclic strain hardening characteristics are more sensitive to rising confining pressures during the initial compaction *** finding is that compared with monotonic loading,more shear microcracks are generated during every reloading stage,but these microcracks tend to be dispersed and lessen the likelihood of large shear fracture *** transition from elastic to plastic behavior varies depending on the parameters of each test(confinement,volume fraction,and cyclic rate),and an interesting finding was that the transformation to plastic behavior is significantly lower under the conditions of 0.73 rock volume fraction,400 N/s cyclic loading rate,and 9 MPa *** the findings have important practical implications on t

关键词： Rock and backfill Triaxial cyclic loading Volume fraction Damage evolution 3D visualization

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Managerial perspectives of scaling up robotic-assisted surgery in healthcare systems:A systematic literature review

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Laparoscopic, Endoscopic and Robotic Surgery 2024年第3期7卷 113-122页

作者： Ravichandran Anitha Komattu Chacko john Gnanadhas Jabarethina Sri Ramachandra Faculty of Management Sciences Sri Ramachandra Institute of Higher Education and Research(Category-I Deemed to be University)ChennaiIndia

Objectives Robotic-assisted surgery(RAS)is a minimally invasive technique practiced in multiple *** training is essential for the acquisition of RAS *** cost of RAS is considered to be high,which makes it a burden for institutes and unaffordable for *** systematic literature review(SLR)focused on the various RAS training methods applied in different surgical specialties,as well as the cost elements of RAS,and was to summarize the opportunities and challenges associated with scaling up *** An SLR was carried out based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses reporting *** PubMed,EBSCO,and Scopus databases were searched for reports from January 2018 through January ***-text reviews and research articles in the English language from Asia-Pacific countries were *** that outlined training and costs associated with RAS were *** The most common training system is the da Vinci *** simulation technique,which includes dry-lab,wet-lab,and virtual reality training,was found to be a common and important *** cost of RAS encompasses the installation and maintenance costs of the robotic system,the operation theatre rent,personnel cost,surgical instrument and material cost,and other miscellaneous *** synthesis of SLR revealed the challenges and opportunities regarding RAS training and *** The results of this SLR will help stakeholders such as decision-makers,influencers,and end users of RAS to understand the significance of training and cost in scaling up RAS from a managerial *** any healthcare innovation to reach a vast population,cost-effectiveness and standard training are crucial.

关键词： da Vinci system Healthcare Robotic-assisted surgery Robotic surgery Robotic training Robotic surgery cost

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A stability evaluation method for deep-seated toppling in the upper Lancang river,Southwestern China

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2388-2410页

作者： Yibing Ning Huiming Tang Jianbing Peng Yanjun Shen john V.Smith Bocheng Zhang College of Geological Engineering and Geomatics Chang’an UniversityXi’an710054China Academy of Yellow River Sciences of Shaanxi Province Chang’an UniversityXi’an710054China Badong National Observation and Research Station of Geohazards China University of GeosciencesWuhan430074China School of Engineering RMIT UniversityMelbourne3001Australia

Deep-seated toppling in the upper reaches of the Lancang River,southwest China involves deformations exceeding 100 m in *** slope deformation is initiated by river downcutting and evolves distinctive characteristics with a depth of river *** this study,we propose a system for evaluating the stability of deep-seated toppled slopes in different evolutionary *** system contains identification criteria for each evolutionary stage and provides the corresponding stability evaluation *** on the mechanical and kinematic analysis of slope blocks,the specific stage of slope movement can be identified in the field through outcrop mapping,in situ tests,surface displacement monitoring,and adit and borehole *** stability evaluation methods are established based on the limiting equilibrium theory and the strain compatibility between the undisturbed zone and the toppled ***,several sample slopes in different evolution stages have been investigated to verify the applicability and accuracy of the proposed stability evaluation *** results indicate that intense tectonic activity and rapid river incision lead to a maximum principal stress ratio exceeding 10 near the slope surface,thus triggering widespread toppling deformations along the river *** considering the losses of joint cohesion during the further rotation process,the safety factor of the slope drops by 7%e28%.The self-stabilization of toppling deformation can be recognized by the layer symmetry configuration after the free rotation of the deflected *** toppled rock blocks mainly suffer sliding failures beyond the layer symmetry *** factor of safety of the K73 rockslide decreased from 1.17 to 0.87 by considering the development of the potential sliding surface and the toesaturated zone.

关键词： Stability evaluation Deep-seated toppling Evolutionary process Reservoir impoundment Rock slope

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Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang Zhikang Shuai Yang Li Zhibing Wang Xiangyang Wu Xia Shen Z.john Shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(Z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(R<0)of the port the overall impedance amplifies the internal resonance source at reactance zero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(R<0),there exists no zero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

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