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Pressurized environments directly influence friction and wear of dry steel contacts—Investigations in a novel high fluid pressure tribometer

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Friction 2024年第7期12卷 1599-1617页

作者： Paul ReICHLe Jakob BARZ Georg UMLAUF Günter e.M.TOVAR Institute of Interfacial Process engineering and Plasma Technology(IGVP) University of StuttgartStuttgart 70569Germany Fraunhofer Institute for Interfacial engineering and Biotechnology(IGB) Stuttgart 70569Germany

To reduce the usage of classical lubricants in deep drawing,a new tribological system based on volatile lubricants was ***,a volatile medium is injected under high pressure into the interstice between drawing tool and sheet *** on temperature and pressure,the temporary lubricant may exist in its gaseous or liquid *** this study,a novel high fluid pressure tribometer was designed to investigate the friction and wear of dry steel contacts under comparable conditions like in dry deep ***,a new ball-on-disc tribometer was designed and integrated into a high-pressure *** specifically investigate the effects of different environments(technical air,liquid and gaseous carbon dioxide,nitrogen,argon)at atmospheric and high pressure(0.1 MPa,6 MPa)on tribology,the specimens and all components were operating *** the experiments,the friction was measured *** show that the highest friction occurs in air and the lowest in carbon dioxide *** to the experiments,the wear of the specimens was assessed along with changes in surface chemistry related to tribochemical ***,the tribology of the dry sliding contacts is correlated to changes of the surface *** differences as well as similarities regarding the different fluid environments are *** the results show,the differences between the media used are most pronounced at elevated ***,this work gives clear indications on the suitability of volatile lubricants in dry friction or rather gas lubrication,especially for dry deep drawing.

关键词： dry friction and dry wear gas lubrication carbon dioxide tribo-layer dry metal forming

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Translating Difference:Reflections on the Interface between Novelistic Discourse and World Literature

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Journal of Foreign Languages and Cultures 2024年第1期8卷 16-30页

作者： e.V.RAMAKRISHNAN Central University of Gujarat

The present essay examines two moments from the evolution of the modern Malayalam novel,in relation to the reception of two classics in world literature,namely Victor Hugo's Les Miserables translated into Malayalam between 1925 and 1927 and Garcia Marquez's One Hundred Years of Solitude translated in *** translation of Hugo's novel energized the scene of Malayalam fiction by infusing new modes of representation and widening the intellectual horizons of writers in general,and novelists in *** echoes of Les Miserables could be heard in Malayalam fiction well into the *** struggles against colonial and feudal authorities in Kerala,provided a fertile context for the imaginative interpretation of Hugo's humanist *** paper illustrates this point through close readings of critical essays,autobiographical narratives and debates on the nature of *** fascination of Malayali readers with Garcia Marquez has resulted in the translation of his entire corpus into *** realism as pioneered by Garcia Marquez liberated the Malayalam novelistic narrative from social realist and modernist *** colonial disruption of oral narratives,the consequent cultural amnesia and the struggle to reclaim one's forgotten past are themes that struck a chord in Malayalam writers of *** a detailed discussion of the novel,Moustache by ***,the interface between novelistic discourse and world literature is mapped in the latter part of the essay.

关键词： Malayalam literature translation difference world literature magic realism caste resistance

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Burden of gallstone disease in the United States population:Prepandemic rates and trends

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World Journal of Gastrointestinal Surgery 2024年第4期16卷 1130-1148页

作者： Aynur Unalp-Arida Constance e Ruhl National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of HealthBethesdaMD 20892-5458United States Social&Scientific Systems Inc.DLH Holdings Corp CompanySilver SpringMD 20910United States

BACKGROUND Gallstone disease is one of the most common digestive disorders in the United States and leads to significant morbidity,mortality,and health care *** To expand on earlier findings and investigate prepandemic rates and trends in the gallstone disease burden in the United States using national survey and claims *** The National Ambulatory Medical Care Survey,National Inpatient Sample,Nationwide emergency Department Sample,Nationwide Ambulatory Surgery Sample,Vital Statistics of the United States,Optum Clinformatics®Data Mart,and Centers for Medicare and Medicaid Services Medicare 5%Sample and Medicaid files were used to estimate claims-based prevalence,medical care including cholecystectomy,and mortality with a primary or other gallstone *** were age-adjusted(for national databases)and shown per 100000 *** Gallstone disease prevalence(claims-based,2019)was 0.70%among commercial insurance enrollees,1.03%among Medicaid beneficiaries,and 2.09%among Medicare beneficiaries and rose over the previous ***,in the United States population,gallstone disease contributed to approximately 2.2 million ambulatory care visits,1.2 million emergency department visits,625000 hospital discharges,and 2000 deaths *** had higher medical care rates with a gallstone disease diagnosis,but mortality rates were higher among *** had higher ambulatory care visit and hospital discharge rates compared with Whites,but not mortality *** had lower ambulatory care visit and mortality rates,but similar hospital discharge rates compared with *** the study period,ambulatory care and emergency department visit rates with a gallstone disease diagnosis rose,while hospital discharge and mortality rates *** commercial insurance enrollees,rates were higher compared with national data for ambulatory care visits and hospitalizations,but lower for emergency department ***

关键词： Gallstone disease Burden Cholecystectomy Mortality Health care use Cholelithiasis Gallstones epidemiology

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High seed losses in mountain birch(Betula pubescens ***)and developmental,ecological,and environmental correlates

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Journal of Plant ecology 2024年第4期17卷 56-69页

作者： Guorun Oskarsdottir Thora e.Thorhallsdottir Kristin Svavarsdottir University of Iceland 102 ReykjavíkIceland Land and Forest Iceland ReykjavíkIceland

Plants typically experience great losses from their reproductive potential represented by ovule production to the post-dispersal crop of viable *** examined seed density and viability in a founder population of mountain birch(Betula pubescens ***),aiming to quantify losses at different stages and examine potential selection forces on the reproduction success of the founder generation of an isolated *** the time of the study(2017-2020),the population had recently reached reproductive maturity,following its colonization around 1990 through long-distance dispersal onto an early successional outwash plain in southeast *** densities were high,but 89% of apparently intact seeds did not contain an embryo,despite being visually indistinguishable from filled *** evident losses amounted to about 45% of the total seed crop and were mostly due to predation by the gall midge Semudobia *** all losses were accounted for,2.7% of the seed crop remained viable and *** limitation may partially explain the high incidence of empty *** flower production is compatible with the predator satiation hypothesis but cannot explain pre-dispersal *** adaptation to predation,masting,appears poorly developed in *** results suggest the presence of constraints on the reproduction potential of the new island population,that are more limiting than in neighbouring populations,and we discuss their developmental,ecological,and environmental correlates.

关键词： Betula pubescens ssp.tortuosa(Ledeb.)Nyman Iceland seed quality seed losses Semudobia betulae sub-arctic

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Influence of Methane-Hydrogen Mixture Characteristics on Compressor Vibrations

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Fluid Dynamics & Materials Processing 2024年第5期20卷 1031-1043页

作者： Vladimir Ya.Modorskii Ivan e.Cherepanov High Performance Computing Center Perm National Research Polytechnic UniversityPerm614990Russia

A transition to clean hydrogen energy will not be possible until the issues related to its production, transportation,storage, etc., are adequately resolved. Currently, however, it is possible to use methane-hydrogen *** gas can be transported using a pipeline system with the required pressure being maintained by gascompression stations. This method, however, is affected by some problems too. Compressors emergency stopscan be induced by vibrations because in some cases, mechanical methods are not able to reduce the vibrationamplitude. As an example, it is known that a gas-dynamic flow effect in labyrinth seals can lead to increasedvibrations. This paper presents the numerical simulation of rotor oscillations taking into account a gas-dynamicload. The influence of a transported mixture on the oscillatory process is investigated. Mixtures consisting ofmethane and hydrogen in various proportions and an air mixture are considered. The results are discussed forvarious operating pressures and include the rotor motion trajectories and oscillation frequency spectra obtainednumerically. It is shown that the gas mixture composition has a significant effect on the oscillations and theiroccurrence. Hydrogen as a working fluid reduces the vibration amplitude. Operating a compressor with hydrogenleads to a decrease in the resonant frequency, bringing it closer to the operating one. However, the operatingpressure at which maximum oscillations are observed depends slightly on the gas mixture composition.

关键词： Seal stabilities vibration FSI CFD multiphase flows hydrogen

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Landau quantization effects on damping Kawahara solitons in electron–positron–ion plasma in rotating ionized medium

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Communications in Theoretical Physics 2024年第10期76卷 143-152页

作者： e I el-Awady S Hussain N Akhtar Department of Physics Faculty of Science Port Said University Theoretical Physics Division (TPD) PINSTECH

For the dynamics of three-dimensional electron–positron–ion plasmas, a fluid quantum hydrodynamic model is proposed by considering Landau quantization effects in dense ***–neutral collisions in the presence of the Coriolis force are also considered. The application of the reductive perturbation technique produces a wave evolution equation represented by a damped Korteweg–de Vries equation. This equation, however, is insufficient for describing waves in our system at very low dispersion coefficients. As a result, we considered the highest-order perturbation, which resulted in the damped Kawahara equation. The effects of the magnetic field, Landau quantization, the ratio of positron density to electron density, the ratio of positron density to ion density, and the direction cosine on linear dispersion laws as well as soliton and conoidal solutions of the damped Kawahara equation are explored. The understanding from this research can contribute to the broader field of astrophysics and aid in the interpretation of observational data from white dwarfs.

关键词： Coriolis force Kawahara equation Landau quantization magnetoplasmas quantum plasma solitary and cnoidal waves

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Artificial intelligence meets body sense: task-driven neural networks reveal computational principles of the proprioceptive pathway

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Signal Transduction and Targeted Therapy 2024年第8期9卷 3147-3149页

作者： Leonard e.van Dyck Frank Bremmer Katharina Dobs Department of Psychology Justus Liebig University GiessenGiessenGermany Max Planck Institute for Human Cognitive and Brain Sciences LeipzigGermany Center for Mind Brain and BehaviorUniversities of MarburgGiessenand DarmstadtMarburgGermany Department of Neurophysics Philipps-Universitat MarburgMarburgGermany

In a recent study published in Cell,Marin Vargas and Bisi et al.1 present an innovative approach to unravel the computational principles underlying proprioceptive processing in non-human *** findings showcase the utility of task-driven modeling in advancing neuroscience and offer translational potential by providing seminal insights into the goals and mechanisms by which the brain encodes body position and movements.

关键词： networks neural principles

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A Proposed Feature Selection Particle Swarm Optimization Adaptation for Intelligent Logistics--A Supply Chain Backlog elimination Framework

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Computers, Materials & Continua 2024年第6期79卷 4081-4105页

作者： Yasser Hachaichi Ayman e.Khedr Amira M.Idrees College of Computing and Information Technology at Khulais Department of Information SystemsUniversity of JeddahJeddah21959Saudi Arabia Faculty of Computers and Information Technology Future University in EgyptCairo11835Egypt

The diversity of data sources resulted in seeking effective manipulation and *** challenge that arises from the increasing dimensionality has a negative effect on the computation performance,efficiency,and stability of *** of the most successful optimization algorithms is Particle Swarm Optimization(PSO)which has proved its effectiveness in exploring the highest influencing features in the search space based on its fast convergence and the ability to utilize a small set of parameters in the search *** research proposes an effective enhancement of PSO that tackles the challenge of randomness search which directly enhances PSO *** the other hand,this research proposes a generic intelligent framework for early prediction of orders delay and eliminate orders backlogs which could be considered as an efficient potential solution for raising the supply chain *** proposed adapted algorithm has been applied to a supply chain dataset which minimized the features set from twenty-one features to ten significant *** confirm the proposed algorithm results,the updated data has been examined by eight of the well-known classification algorithms which reached a minimum accuracy percentage equal to 94.3%for random forest and a maximum of 99.0 for Naïve ***,the proposed algorithm adaptation has been compared with other proposed adaptations of PSO from the literature over different *** proposed PSO adaptation reached a higher accuracy compared with the literature ranging from 97.8 to 99.36 which also proved the advancement of the current research.

关键词： Optimization particle swarm optimization algorithm feature selection logistics supply chain management backlogs

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On B(5,20)2-Groups

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Algebra Colloquium 2024年第3期31卷 429-440页

作者： e.A.Alhassan Y.L.Tan Y.Li School of Mathematical Sciences Jiangsu UniversityZhenjiangJiangsu 212013China Department of Mathematics Brock UniversitySt.CatharinesOntario L2S 3A1Canada

A finite group G is said to be a B(n,k)group if for any n-element subset[a_(1),…,a_(n)]of G,|{a_(i)a_(j)|1≤i,j≤n}|≤*** is of interest to characterize the structure of B(n,k)groups for n(n+1)/2≤k≤n^(2)-*** B(5,k)groups for 15≤k≤19 have been investigated by several *** this paper,we give a complete characterization of B(5,20)2-groups by showing there are five classes of such groups which are nontrivial and nonabelian.

关键词： B(n,k)groups small squaring property central extension GAP

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Juvenile survival curves in a solitary ground squirrel with a prolonged hibernation:effects of individual characteristics,environment,and maternal investment

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Current Zoology 2024年第1期70卷 13-23页

作者： Nina A.Vasilieva Liudmila e Savinetskaya Andrey V.Tchabovsky A.N.Severtsov Institute of ecology and evolution Russian Academy of SciencesMoscow 119071Russia

Juvenile survival is a key life-history influence on population dynamics and adaptive *** analyzed the effects of individual chara-cteristics,early environment,and maternal investment on juvenile survival in a large solitary hibernating rodent-yellow ground squirrel Spermophilus fulvus using Cox mixed-effects *** 48%of weaned pups survived to dispersal and 17%survived to *** life expectancy was primarily determined by individual characteristics and,to a lesser extent,by the early *** strongest and pos-itive predictor of juvenile survival was body mass which crucially affected mortality immediately after *** suffered higher mortality than females after the onset of dispersal;however,the overall difference between sexes was partly masked by high rates of mortality in the first days after emergence in both *** emerged juveniles had lower life expectancy than the earliest *** overall effect of local juvenile density was *** lactation did not enhance juvenile survival:Pups nursed longer survived shorter than the young nursed for a shorter *** findings support the hypothesis that females of *** cannot effectively regulate maternal expenditures to mitigate the effects of unfavorable conditions on their *** strategy to deal with seasonal time constraints on life history in female *** suggests an early termination of maternal care at the cost of juvenile quality and *** female reproductive strategy corresponds to a"fast-solitary"life of folivorous desert-dwelling *** and other solitary ground squirrels with prolonged hibernation.

关键词： early-life conditions ground squirrels hibernation juvenile mortality maternal investment survival curves

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