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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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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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Scanning transmission electron microscopy and atom probe tomography analysis of non-stoichiometry long-period-stacking-ordered structures in Mg-Ni-Y/Sm alloys

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Journal of Magnesium and Alloys 2024年第3期12卷 954-965页

作者： Yimeng Chen Manuel Legrée Jean-Louis Bobet Alexander Kvit CAMeCA Instruments Inc MadisonWI 53711USA ICMCB Universitéde BordeauxPessacCEDEX 33608France NIAC&Materials Science Department University of WisconsinMadisonWI 53706USA

The long-period-stacking-ordered(LPSO)structure affects the mechanical,corrosion and hydrolysis properties of Mg *** current work employs high angle annular dark field-scanning transmission electron microscopy(HAADF-STeM)and atom probe tomography(APT)to investigate the structural and local chemical information of LPSO phases formed in Mg-Ni-Y/Sm ternary alloys after extended isothermal *** on the alloying elements and their concentrations,Mg-Ni-Y/Sm develops a two-phase LPSO+α-Mg structure in which the LPSO phase contains defects,hybrid LPSO structure,and Mg ***-STeM and APT indicate non-stoichiometric LPSO with incomplete Ni_(6)(Y/Sm)_(8) *** addition,the APT quantitatively determines the local composition of LPSO and confirms the presence of Ni within the Mg bonding *** results provide insight into a better understanding of the structure and hydrolysis properties of LPSO-Mg alloys.

关键词： Magnesium alloys Long-range ordering Atom probe tomography(APT) STeM HAADF Hydrolysis properties.

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Could mammalian inorganic polyphosphate be a crucial signaling molecule in neurological disorders?

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Neural Regeneration Research 2024年第4期19卷 701-702页

作者： Renata Torres Da Costa Maria e.Solesio Rutgers University Department of BiologyCamdenNJUSA

Since the early stages of life on earth,cellular metabolism has evolved to adapt to fluctuations in nutrient and oxygen *** this context,mammals,which are probably the organisms that show one of the highest levels of metabolic complexity,have developed an elegant system that uses constant and rechargeable energy sources of modulate their *** homeostasis is especially important in the central nervous system,as neurons and other cells in the brain are highly susceptible to fluctuations in nutrients and oxygen availability.

关键词： metabolism homeostasis neurological

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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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Commentary on “Does light-intensity physical activity moderate the relationship between sitting time and adiposity markers in adolescents?”

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Journal of Sport and Health Science 2024年第4期13卷 453-454页

作者： Barbara e.Ainsworth Amanda M.Ferland School of exercise and Health Shanghai University of SportShanghai 200433China Department of Orthopedics Tongji UniversityShanghai 200092China

In the September 2022 issue of the Journal of Sport and Health Science,Ayala et al.1 published results from a cross-sectional study where they tested the hypothesis that light intensity physical activity(LIPA,1.6-2.9 metabolic equivalents(MeTs))moderates the relationship between sitting time and adiposity in 219 Australian adolescents aged 14±1.6 years(mean±SD).

关键词： metabolic light

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Consequences of early life stress on the structure and function of the adult mouse retina

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Neural Regeneration Research 2024年第1期19卷 150-151页

作者： Juan S.Calanni Ruth e.Rosenstein Laboratory of Retinal Neurochemistry and experimental Ophthalmology Department of Human BiochemistrySchool of Medicine/CEFyBOUniversity of Buenos Aires/CONICETBuenos AiresArgentina

early-life stress(eLS)refers to a period of environmental/social deprivation,physica l,sexual or emotional abuse,neglect,severe and/or chronic trauma in the prenatal/early postnatal stage,which is closely related to many adverse psychiatric disorders later in life,such as depressive disorder,substance abuse,dysthymia,panic,anxiety,and suicidal behavior in adulthood(Waters and Gould,2022).

关键词： stress life Gould

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Comparison between seismic analysis of twisting and regular 52-story towers considering soil-structure interaction

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earthquake engineering and engineering Vibration 2024年第3期23卷 663-675页

作者： Mohamed Naguib Abouelsaad Mohammed Shaaban Salah el Bagalaty Mohamed e.el Madawy Structural engineering Department Faculty of EngineeringMansura UniversityMansoura 35511Egypt Faculty of engineering Delta University for Science and TechnologyGamasa 35712Egypt

A dynamic analysis of both twisting and regular towers is carried out to determine the results of considering soil-structure interaction(SSI)on high-rise *** addition,the difference between the seismic performance of using twisting towers over regular ones is *** twisting tower is a simulation of the evolution Tower(Moscow).The towers’skeletons consist of RC elements and rest on a reinforced concrete piled-raft *** soil model is considered as multi-layered with the same soil properties as the zone chosen for the analysis(New Mansoura City,egypt).The only difference between both towers is their shape in *** whole system is modelled and analyzed in a single step as one full 3D model,which is known as the direct approach in *** analyses are carried out using finite-element software(Midas GTS NX).Dynamic output responses due to three records of seismic loads are proposed and presented in some *** on the results,it is concluded that SSI has a considerable effect on the dynamic response of tall buildings mainly because of the foundation flexibility,as it leads to lengthening the vibration period,increasing the story drift and the base shear for both cases.

关键词： soil-structure interaction seismic analysis twisting towers base shear story drift finite element method Midas GTS NX

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