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Friction and wear performance of polyether ether ketone(PEEK)polymers in three lubrication regimes

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Friction 2024年第4期12卷 670-682页

作者： Davide MASSOCCHI Nora LECIS Marco LATTUADA Davide SCAGLIA steven CHATTERTON Paolo PENNACCHI Department of Mechanical Engineering Politecnico di MilanoMilan 20156Italy Eni SpA Downstream product R&DLombardia 20097Italy Eurobearings S.R.L. Lombardia 29016Italy

This experimental study investigates the friction and wear of three coatings commonly used in industrial applications,particularly in hydrodynamic *** three materials under investigation were Babbitt,polyether ether ketone(PEEK)reinforced with 15%carbon fibers,and PEEK reinforced with 20%carbon *** first polymer material was extruded,while the other was produced by fused deposition modelling(FDM).The materials were subjected to sliding tests in a pin-on-disc configuration,with a steel ball serving as the counter *** tests were conducted at room temperature,with a load of 10 N and under three different lubrication conditions:dry,grease,and *** linear speed was set at 0.3 m/s for the dry and semi-solid lubrication tests,while for the oil tests,the speed was set at 0.25 m/*** greases used had consistency grades of NGLI 000 and NGLI *** ISO VG 68 circulation oil was used for the oil lubrication ***,thermodynamic analyses were performed under the most severe conditions(i.e.,dry)to investigate the steel-Babbitt and steel-PEEK contact.

关键词： hydrodynamic bearings polyether ether ketone(PEEK)polymers additive manufacturing grease lubrication sliding oil lubrication ball-on-disk tribology

Conventional and micro scale finite element modeling for metal cutting process:A review

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Chinese Journal of Aeronautics 2024年第2期37卷 199-232页

作者： Le WANG Caixu YUE Xianli LIU Ming LI Yongshi XU steven Y.LIANG Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of EducationHarbin University of Science and TechnologyHarbin 150080China George W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlanta 30332USA

The metal cutting process is accompanied by complex stress field,strain field,temperature *** comprehensive effects of process parameters on chip morphology,cutting force,tool wear and residual stress are complex and *** element method(FEM)is considered as an effective method to predict process variables and reveal microscopic physical phenomena in the cutting ***,the finite element(FE)simulation is used to research the conventional and micro scale cutting process,and the differences in the establishment of process variable FE simulation models are distinguished,thereby improving the accuracy of FE *** reliability and effectiveness of FE simulation model largely depend on the accuracy of the simulation method,constitutive model,friction model,damage model in describing mesh element,the dynamic mechanical behavior of materials,the tool-chip-workpiece contact process and the chip formation *** this paper,the FE models of conventional and micro process variables are comprehensively and up-to-date reviewed for different materials and machining *** purpose is to establish a FE model that is more in line with the real cutting conditions,and to provide the possibility for optimizing the cutting process *** development direction of FE simulation of metal cutting process is discussed,which provides guidance for future cutting process modeling.

关键词： Conventional and micro scale Finite element simulation Metal cutting process Micro cutting Modeling

Oxygen uptake response to switching stairs exercise by non-parametric modeling

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Control Theory and Technology 2024年第2期22卷 315-325页

作者： Hairong Yu Chenyu Zhang Kai Cao Hamzah M.Alqudah steven Weidong Su Key Laboratory of Child Development and Learning Science of Ministry of Education and the School of Biological Science and Medical Engineering Southeast UniversityNanjing210096JiangsuChina College of Artificial Intelligence and Big Data for Medical Science Shandong First Medical University and Shandong Academy of Medical SciencesJinan250117ShandongChina Faculty of Engineering and Information Technology University of Technology SydneyUltimoNSW2007Australia

Oxygen uptake plays a crucial role in the evaluation of endurance performance during exercise and is extensively utilized for metabolic assessment. This study records the oxygen uptake during the exercise phase (i.e., ascending or descending) of the stair exercise, utilizing an experimental dataset that includes ten participants and covers various exercise periods. Based on the designed experiment protocol, a non-parametric modeling method with kernel-based regularization is generally applied to estimate the oxygen uptake changes during the switching stairs exercise, which closely resembles daily life activities. The modeling results indicate the effectiveness of the non-parametric modeling approach when compared to fixed-order models in terms of accuracy, stability, and compatibility. The influence of exercise duration on estimated fitness reveals that the model of the phase-oxygen uptake system is not time-invariant related to respiratory metabolism regulation and muscle fatigue. Consequently, it allows us to study the humans’ conversion mechanism at different metabolic rates and facilitates the standardization and development of exercise prescriptions.

关键词： Non-parametric modeling Interval stair training exercise Kernel method.Cardiorespiratory response Oxygen uptake

Simulation of the SMILE Soft X-ray Imager response to a southward interplanetary magnetic field turning

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Earth and Planetary Physics 2024年第1期8卷 39-46页

作者： Andrey Samsonov Graziella Branduardi-Raymont steven Sembay Andrew Read David Sibeck Lutz Rastaetter Mullard Space Science Laboratory University College LondonDorking RH56NTUK Leicester University Leicester LE17RHUK Goddard Space Flight Center National Aeronautics and Space AdministrationGreenbeltMD 20771USA

The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic *** simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration *** making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)*** root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.

关键词： magnetopause magnetic reconnection solar wind charge exchange southward interplanetary magnetic field numerical modeling Solar wind Magnetosphere Ionosphere Link Explorer(SMILE) Soft X-ray Imager

An examination of thematic research,development,and trends in remote sensing applied to conservation agriculture

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International Soil and Water Conservation Research 2024年第1期12卷 77-95页

作者： Zobaer Ahmed Aaron Shew Lawton Nalley Michael Popp V.steven Green Kristofor Brye Center for Advanced Spatial Technologies University of ArkansasFayettevilleARUSA Environmental Dynamics Program University of ArkansasFayettevilleARUSA Department of Agricultural Economics and Agribusiness University of ArkansasFayettevilleARUSA College of Agriculture Arkansas State UniversityJonesboroARUSA University of Arkansas System Division of Agriculture Little RockARUSA Department of Crop Soiland Environmental SciencesUniversity of ArkansasFayettevilleARUSA

Conservation agriculture seeks to reduce environmental degradation through sustainable management of agricultural *** the 1990s,agricultural research has been conducted using remote sensing technologies;however,few previous reviews have been conducted focused on different conservation management *** of the previous literature has focused on the application of remote sensing in agriculture without focusing exclusively on conservation practices,with some only providing a narrative review,others using biophysical remote sensing for quantitative estimates of the bio-geo-chemical-physical properties of soils and crops,and few others focused on single agricultural management *** paper used the preferred reporting items for systematic review(PRISMA)methodology to examine the last 30 years of thematic research,development,and trends associated with remote sensing technologies and methods applied to conservation agriculture research at various spatial and temporal scales.A set of predefined key concepts and keywords were applied in three databases:Scopus,Web of Science,and Google Scholar.A total of 188 articles were compiled for initial examination,where 68 articles were selected for final analysis and grouped into cover crops,crop residue,crop rotation,mulching,and tillage *** on conservation agriculture research using remote sensing have been increasing since 1991 and peaked at 10 publications in *** the 68 articles,94%used a pixel-based,while only 6%used an object-based classification *** to 2005,tillage practices were abundantly studied,then crop residue was a focused theme between 2004 and *** 2012 to 2020,the focus shifted again to cover *** spectral indices were used in 76%of the 68 *** examination offered a summary of the new potential and identifies crucial future research needs and directions that could improve the contribution of remote sensing to the provision of long-term operat

关键词： Remote sensing Conservation agriculture Classification algorithm Spatial resolution Satellite Spectral indices PRISMA

Anatomic location of the first dorsal extensor compartment for surgical De-Quervain’s tenosynovitis release:A cadaveric study

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World Journal of Orthopedics 2024年第4期15卷 379-385页

作者： Aditya Thandoni William Nicholas Yetter steven Michael Regal Department of Orthopaedic Surgery Allegheny Health NetworkPittsburghPA 15212United States

BACKGROUND De-Quervain’s tenosynovitis is a disorder arising from the compression and irritation of the first dorsal extensor compartment of the *** who fail conservative treatment modalities are candidates for surgical ***,risks with surgery include damage to the superficial radial nerve and an incomplete release due to inadequate ***,there is a paucity of literature demonstrating the exact anatomic location of the first dorsal extensor compartment in reference to surface ***,this cadaveric study was performed to determine the exact location of the first extensor compartment and to devise a reliable surgical incision to prevent *** To describe the location of the first dorsal compartment in relation to bony surface landmarks to create replicable surgical *** Six cadaveric forearms,including four left and two right forearm specimens were *** were performed by a single fellowship trained upper extremity orthopaedic *** of the first dorsal compartment from landmarks such as Lister’s tubercle,the wrist crease,and the radial styloid were *** variables studied included the presence of the superficial radial nerve overlying the first dorsal compartment,additional compartment subsheaths,number of abductor pollicis longus(APL)tendon slips,and the presence of a *** Distance from the radial most aspect of the wrist crease to the extensor retinaculum was 5.14 mm±0.80 *** distance from Lister’s tubercle to the distal aspect of the extensor retinaculum was 13.37 mm±2.94 ***’s tubercle to the start of the first dorsal compartment was 18.43 mm±2.01 *** radial styloid to the initial aspect of the extensor retinaculum measured 2.98 mm±0.99 *** retinaculum length longitudinally on average was 26.82 mm±3.34 *** cadaveric forearms had separate extensor pollicis brevis *** average number of APL tendon slips was th

关键词： De-Quervain’s tenosynovitis First extensor compartment Cadaveric study Superficial radial nerve Radial styloid Lister’s tubercle

Multiple interface coupling on natural tourmaline enables high-efficiency removal of antibiotic:Superior property and mechanism

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Journal of Environmental Sciences 2024年第6期140卷 242-254页

作者： Jingjing Cui Xiangyu Liu Feifan Qie Chengzhe Xie Qingdong He Jian Liu steven L.Suib Wenbo Wang College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China Department of Chemistry University of ConnecticutStorrsCT 06269-3060United States

Reasonably designing highly active,environmentally friendly,and cost-effective catalysts for efficient elimination of pollutants from water is desirable but ***,an efficient heterogeneous photo-Fenton catalyst tourmaline(TM)/tungsten oxide(WO_(3-x))(named TW10)containing tungsten/boron/iron(W/B/Fe)synergistic active centers and 90%of cheap natural tourmaline(TM)mineral rich in Fe and B *** TW10 catalyst can quickly activate peroxymonosulfate(PMS)to generate massive active free radicals,which may induce the rapid and efficient degradation of tetracycline(TC).The TW10/PMS/Visible light system can effectively degrade up to 98.7%of tetracycline(TC)in actual waters(***,Yellow River,and Yangtze River water),and the catalytic degradation rates reach 1.65,5.569,and 2.38 times higher than those of TM,WO_(3-x),and commercial P25(Degussa,Germany),*** addition,the catalyst can be recycled and reused multiple *** spin resonance spectroscopy(EPR),X-ray photoelectron spectroscopy(XPS),and liquid chromatograph-mass spectrometer(LC-MS)analyses confirm that the synergistic catalytic effect of W/B/Fe sites on the TW10 catalyst accelerates the electron transfer between Fe(Ⅱ)and Fe(Ⅲ),as well as between W(Ⅴ)and W(Ⅵ),and thus promotes the rapid degradation of *** catalytic reaction mechanism and degradation pathway of TC were *** work provides a feasible route for the design and development of new eco-friendly and efficient catalyst.

关键词： Tourmaline(TM) Fenton-like catalyst Tungsten oxide Peroxymonosulfate Antibiotic

Rodent biology and ecologically based rodent management(EBRM)-25 years of progress through promoting multidisciplinary research

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Integrative Zoology 2024年第1期19卷 2-7页

作者： Grant R. SINGLETON Lyn A. HINDS Rhodes MAKUNDI steven R. BELMAIN Natural Resources Institute University of Greenwich Kent UK CSIRO Health and Biosecurity Canberra ACT Australia African Centre of Excellence for Innovative Rodent Pest Management and Biosensor Technology Development Sokoine University of Agriculture Morogoro Tanzania Institute of Pest Management Sokoine University of Agriculture Morogoro Tanzania

“During rodent outbreak years in eastern Africa,lo-cally,more than 80%of the potential harvest may be lost,but even in non-outbreak periods,rodents cause chronic damage to crops….The pest rodent story in Africa in-volves several species embedded in a broad and variable landscape with highly variable densities.”(Leirs et al.2010).

关键词： damage crops

Lipid concentration and composition in xylem sap of woody angiosperms from a tropical savanna and a seasonal rainforest

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Plant Diversity 2024年第1期46卷 126-133页

作者： Ling-Bo Huang Xinyi Guan Amy Ny Aina Aritsara Jun-Jie Zhu steven Jansen Kun-Fang Cao State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources Guangxi Key Laboratory of Forest Ecology and ConservationGuangxi UniversityDaxuedong Road 100NanningGuangxi 530004China Institute of Botany Ulm UniversityAlbert-Einstein-Allee 11Ulm89081Germany

Lipids may play an important role in preventing gas embolisms by coating nanobubbles in xylem *** studies on xylem sap lipids have been reported for temperate plants,and it remain unclear whether sap lipids have adaptational significance in tropical *** this study,we quantify the lipid composition of xylem sap for angiosperm species from a tropical savanna(seven species)and a seasonal rainforest(five species)using mass *** found that all twelve species studied contained lipids in their xylem sap,including galactolipids,phospholipids and triacylglycerol,with a total lipid concentration ranging from 0.09 to 0.26 nmol/*** was no difference in lipid concentration or composition between plants from the two sites,and the lipid concentration was negatively related to species’open vessel ***,savanna species showed little variation in lipid composition between the dry and the rainy *** results support the hypothesis that xylem sap lipids are derived from the cytoplasm of individual conduit cells,remain trapped inside individual conduits,and undergo few changes in composition over consecutive seasons.A xylem sap lipidomic data set,which includes 12 tropical tree species from this study and 11 temperate tree species from literature,revealed no phylogenetic signals in lipid composition for these *** study fills a knowledge gap in the lipid content of xylem sap in tropical trees and provides additional support for their common distribution in xylem sap of woody *** appears that xylem sap lipids have no adaptive significance.

关键词： Xylem sap Lipids Tropical savanna Tropical rainforest Vessels