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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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Effects of a school-based karate intervention on academic achievement,psychosocial functioning,and physical fitness:A multi-country cluster randomized controlled trial

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Journal of Sport and Health Science 2024年第1期13卷 90-98页

作者： Tania Pinto-Escalona Erica Gobbi Pedro L.Valenzuela simon J.Bennett Pierluigi Aschieri Manuel Martin-Loeches Antonio Paoli Oscar Martinez-de-Quel Faculty of Education Complutense University of MadridMadrid 28040Spain Department of Biomolecular Sciences University of Urbino“Carlo Bo”Urbino 61029Italy Department of Systems Biology University of AlcaláMadrid 28805Spain Research Institute for Sport and Exercise Sciences Faculty of ScienceLiverpool John Moores UniversityLiverpoolL33AFUK Italian Judo WrestlingKarate and Martial Arts FederationRome 00122Italy Psychobiology&Methods for the Behavioural Sciences Department Complutense University of MadridMadrid 28040Spain Department of Biomedical Sciences University of PaduaPadua 35122Italy

Purpose:To examine the effects of a school-based karate intervention on academic achievement,psychosocial functioning,and physical fitness in children aged 7-8 ***:Twenty schools in 5 different European countries(2 second-grade classrooms per school)participated in a cluster randomized controlled trial(Sport at School trial).Participants were assigned to either a control group,which continued with their habitual physical education lessons,or to an intervention group,which replaced these lessons with a 1-year karate intervention(Karate Mind and Movement program).A total of 721 children(344 girls and 377 boys,7.4±0.5 years old,mean±SD)completed the study,of which 333 and 388 were assigned to the control group and intervention group,*** included academic performance(average grade),psychosocial functioning(Strengths and Difficulties Questionnaire for parents),and different markers of physical fitness(cardiorespiratory fitness,balance,and flexibility).Results:The intervention provided small but significant benefits compared to the control group for academic achievement(d=0.16;p=0.003),conduct problems(d=-0.28;p=0.003),cardiorespiratory fitness(d=0.36;p0.05).Conclusion:A 1-year school-based karate intervention was effective in improving academic achievement,conduct problems,and physical fitness in primary school *** results support the inclusion of karate during physical education lessons.

关键词： Academic performance Cardiorespiratory fitness Conduct problems Karate Physical fitness

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Interdecadal variability of summer precipitation in the Three River Source Region: Influences of SST and zonal shifts of the East Asian subtropical westerly jet

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Atmospheric and Oceanic Science Letters 2024年第5期17卷 47-53页

作者： Yumeng Liu Xianhong Meng Lin Zhao S-Y.simon Wang Lixia Zhang Zhaoguo Li Chan Wang Yingying An Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouChina Zoige Plateau Wetlands Ecosystem Research Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouChina University of Chinese Academy of Sciences BeijingChina Utah Climate Center Utah State UniversityLoganUSA The State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina

Summer precipitation in the Three Rivers Source Region(TRSR)of China is vital for the headwaters of the Yellow,Yangtze,and Lancang rivers and exhibits significant interdecadal *** study investigates the influence of the East Asian westerly jet(EAWJ)on TRSR rainfall.A strong correlation is found between TRSR summer precipitation and the Jet Zonal Position Index(JZPI)of the EAWJ from 1961 to 2019(R=0.619,p<0.01).During periods when a positive JZPI indicates a westward shift in the EAWJ,enhanced water vapor anomalies,warmer air,and low-level convergence anomalies contribute to increased TRSR summer *** empirical orthogonal function and regression analyses,this research identifies the influence of large-scale circulation anomalies associated with the Atlantic–Eurasian teleconnection(AEA)from the North Atlantic(NA).The interdecadal variability between the NA and central tropical Pacific(CTP)significantly affects TRSR *** influence is mediated through the AEA via a Rossby wave train extending eastward along the EAWJ,and another south of 45°***,the NA–CTP Opposite Phase Index(OPI),which quantifies the difference between the summer mean sea surface temperatures of the NA and the CTP,is identified as a critical factor in modulating the strength of this teleconnection and influencing the zonal position of the EAWJ.

关键词： Summer precipitation East Asian subtropical westerly jet Three River Source Region Atlantic-Eurasian teleconnection

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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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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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Evaluation of ruminal methane and ammonia formation and microbiota composition as affected by supplements based on mixtures of tannins and essential oils using Rusitec

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Journal of Animal Science and Biotechnology 2024年第4期15卷 1607-1622页

作者： Giulia Foggi Melissa Terranova Matteo Daghio Sergej L.Amelchanka Giuseppe Conte simon Ineichen Monica Agnolucci Carlo Viti Alberto Mantino Arianna Buccioni Michael Kreuzer Marcello Mele Department of Agriculture Food and Environment(DAFE)University of Pisa56124 PisaItaly AgroVet‑Strickhof ETH ZurichLindauSwitzerland Department of Agriculture FoodEnvironment and ForestryUniversity of FlorenceFlorence 50144Italy Centro Di Ricerche Agro‑Ambientali“E.Avanzi” University of PisaPisa 56122Italy School of Agricultural Forest and Food Sciences HAFLBern University of Applied SciencesZollikofenSwitzerland Institute of Agricultural Sciences ETH ZurichLindauSwitzerland

Background Dietary supplements based on tannin extracts or essential oil compounds(EOC)have been repeatedly reported as a promising feeding strategy to reduce the environmental impact of ruminant husbandry.A previous batch culture screening of various supplements identified selected mixtures with an enhanced potential to mitigate ruminal methane and ammonia *** these,Q-2(named after quebracho extract and EOC blend 2,composed of carvacrol,thymol,and eugenol)and C-10(chestnut extract and EOC blend 10,consisting of oregano and thyme essential oils and limonene)have been investigated in detail in the present study with the semi-continuous rumen simulation technique(Rusitec)in three independent *** this purpose,Q-2 and C-10,dosed according to the previous study,were compared with a non-supplemented diet(negative control,NC)and with one supplemented with the commercial EOC-based Agolin^(R) Ruminant(positive control,PC).Results From d 5 to 10 of fermentation incubation liquid was collected and analysed for pH,ammonia,protozoa count,and gas *** residues were collected for the determination of ruminal *** d 10,samples of incubation liquid were also characterised for bacterial,archaeal and fungal communities by high-throughput sequencing of 16S rRNA and 26S ribosomal large subunit gene *** of the duration of the fermentation period,Q-2 and C-10 were similarly efficient as PC in mitigating either ammonia(-37%by Q-2,-34%by PC)or methane formation(-12%by C-10,-12%by PC).The PC was also responsible for lower feed degradability and bacterial and fungal richness,whereas Q-2 and C-10 effects,particularly on microbiome diversities,were limited compared to *** All additives showed the potential to mitigate methane or ammonia formation,or both,in vitro over a period of 10 ***,several differences occurred between PC and Q-2/C-10,indicating different mechanisms of *** pronounced defaunation caused by PC a

关键词： Additive Bacteria Continuous culture Degradability Fermentation Fungi Greenhouse gas In vitro Microbiome Rumen

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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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