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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

Advanced strategies for marine antifouling based on nanomaterial-enhanced functional PDMS coatings

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Nano Materials Science 2024年第4期6卷 375-395页

作者： Xiaohui Shi Hao Wei Wenjun Zhou paul e.D.Soto Rodriguez Cunguo Lin Lei Wang Zhijia Zhang School of Materials Science and Chemical engineering Harbin Engineering University Qingdao Innovation and Development Center of Harbin engineering University State Key Laboratory for Marin Corrosion and Protection Luoyang Ship Material Research Institute (LSMRI) Instituto de estudios Avanzados IUDeA Departamento de Física Universidad de La Laguna C/Astrofísico Francisco Sanchez School of Chemistry and Chemical engineering Harbin Institute of Technology

Marine biofouling seriously affects human marine exploitation and transportation activities, to which marine antifouling(AF) coatings are considered to be the most cost-effective solution. Since the mid-20th century, human beings have dedicated their efforts on developing AF coatings with long cycle and high performance, leading to a large number of non-target organisms? distortion, death and marine environmental pollution. Polydimethylsiloxane(PDMS), is considered as one of the representative environment-friendly AF materials thanks to its non-toxic, hydrophobic, low surface energy and AF properties. However, PDMS AF coatings are prone to mechanical damage, weak adhesion strength to substrate, and poor static AF effect, which seriously restrict their use in the ocean. The rapid development of various nanomaterials provides an opportunity to enhance and improve the mechanical properties and antifouling properties of PDMS coating by embedding *** on our research background and the problems faced in our laboratory, this article presents an overview of the current progress in the fields of PDMS composite coatings enhanced by different nanomaterials, with the discussion focused on the advantages and main bottlenecks currently encountered in this field. Finally, we propose an outlook, hoping to provide fundamental guidance for the development of marine AF field.

关键词： Nanomaterials Antifouling PDMS composites environment-friendly Marine biofouling

Quantifying source-sink relationships in leaf-color modified rice genotypes during grain filling

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Journal of Integrative Agriculture 2024年第9期23卷 2923-2940页

作者： Zhenxiang Zhou paul CStruik Junfei Gu Peter e.L.van der Putten Zhiqin Wang Jianchang Yang Xinyou Yin Centre for Crop Systems Analysis Department of Plant SciencesWageningen University&ResearchWageningen 6700 AKThe Netherlands College of Agriculture Yangzhou UniversityYangzhou 225009China

Leaf-color modification can affect canopy photosynthesis,with potential effects on rice yield and yield *** source-sink relationships through crop management is often used to improve crop *** study investigated whether and how modifying leaf color alters source-sink relationships and whether current crop cultivation practices remain applicable for leaf-color modified *** collected data of total biomass and nitrogen(N)accumulation in rice genotypes of four genetic backgrounds and their leaf-color modified variants(greener or yellower)were analyzed,using a recently established modelling method to quantify the source-sink(im)balance during grain *** all leaf-color variants,only one yellower-leaf variant showed a higher source capacity than its normal *** was associated with greater post-flowering N-uptake that prolonged the functional leaf-N duration,and this greater post-flowering N-uptake was possible because of reduced pre-flowering N-uptake.A density experiment showed that current management practices(insufficient planting density accompanied by abundant N application)are unsuitable for the yellower-leaf genotype,ultimately limiting its yield ***-color modification affects source-sink relationships by regulating the N trade-off between pre-and post-flowering uptake,as well as N translocation between source and sink *** best exploit leaf-color modification for improving crop productivity,adjustments of crop management practices are required.

关键词： source-sink relationship biomass nitrogen Oryza sativa leaf-color modification

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The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： paul B.Wignall David P.G.Bond School of earth & environment University of Leeds School of environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(ecades) and the overwhelming evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern Boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Plant-available water capacity of soils at a regional scale:Analysis of fixed and dynamic field capacities

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Pedosphere 2024年第3期34卷 590-605页

作者： Vinod PHOGAT paul RPeTRIe Casandra COLLINS Marcos BONADA South Australian Research and Development Institute GPO Box 397Adelaide SA 5001(Australia) School of Agriculture Food and WineWaite Research InstituteUniversity of AdelaideWaite CampusPMB1Glen Osmond SA 5064(Australia) College of Science and engineering Flinders UniversityBedford Park SA 5042(Australia) The University of New South Wales Sydney NSW 2052(Australia) ARC Training Centre for Innovative Wine Production University of AdelaidePMB1Glen Osmond SA 5064(Australia)

estimation of the plant-available water capacity(PAWC)of soils at a regional scale helps in adopting better land use planning,developing suitable irrigation schedules for crops,and optimizing the use of scarce water *** the current study,72 soil profiles were sampled from the Barossa region of South Australia to estimate pedo-transfer functions deduced from easily estimated soil *** functions were then used to estimate the fixed(10 and 33 kPa)and dynamic pressure head(h_(fc))water contents at field capacity(FC)for minimum drainage flux(0.01 and 0.001 cm d^(-1)),which serves as the upper boundary for plant-available water in *** estimated residual water content was corrected for subsoil constraints,especially the exchangeable sodium percentage(eSP).The results showed that the mean values of h_(fc)in sand-dominated light and medium textured soils(i.e.,sand,loamy sand,sandy loam,and loam)varied in a narrow range(15.8-18.2 kPa),whereas those in the clay-dominated heavy textured soils(i.e.,clay loam)showed a wide range(11.3-49.3 kPa).There were large differences in PAWC for dynamic FC(PAWC_(fc))and fixed FC at 10 kPa(PAWC10),33 kPa(PAWC33),and a mix of 10and 33 kPa(PAWC_(10,33))pressure heads depending on soil ***,the difference between PAWC at 10 kPa and h_(fc)(ΔPAWC_(10))was positive,whereas that between 33 kPa and h_(fc)(ΔPAWC_(33))was negative across all ***,the estimation of PAWC assuming a fixed FC at 10 and 33 kPa pressures(i.e.,PAWC_(10,33))for sandy,clay,and silty soils reduced the difference between fixed and dynamic pressure PAWCs toe *** estimation of PAWC was improved by incorporating the impact of subsoil constraints,such as high eSP,which was more pronounced for clay and silty *** findings demonstrate the inherent inconsistencies between static pressure and flux-based dynamic FC estimations in *** heterogeneity,intra-texture variability,subsoil constraints,and swell

关键词： crop lower limit drained upper limit pedo-transfer function soil hydraulic parameter soil texture

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Understanding the catalysis of chromium trioxide added magnesium hydride for hydrogen storage and Li ion battery applications

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Journal of Magnesium and Alloys 2024年第3期12卷 1117-1130页

作者： D.Pukazhselvan IhsanÇaha Catarina de Lemos Sergey M.Mikhalev Francis Leonard Deepak Duncan paul Fagg Department of Mechanical engineering TEMA-Centre for Mechanical Technology and AutomationUniversity of AveiroAveiro 3810-193Portugal LASI-Intelligent Systems Associate Laboratory Guimarães 4800-058Portugal Nanostructured Materials Group International Iberian Nanotechnology Laboratory(INL)Avenida Mestre Jose VeigaBraga 4715-330Portugal

This study explores how the chemical interaction between magnesium hydride(MgH_(2))and the additive CrO_(3) influences the hydrogen/lithium storage characteristics of MgH_(2).We have observed that a 5 wt.%CrO_(3) additive reduces the dehydrogenation activation energy of MgH_(2) by 68 kJ/mol and lowers the required dehydrogenation temperature by 80℃.CrO_(3) added MgH_(2) was also tested as an anode in an Li ion battery,and it is possible to deliver over 90%of the total theoretical capacity(2038 mAh/g).evidence for improved reversibility in the battery reaction is found only after the incorporation of additives with MgH_(2).In depth characterization study by X-ray diffraction(XRD)technique provides convincing evidence that the CrO_(3) additive interacts with MgH_(2) and produces Cr/MgO *** free energy analyses confirm the thermodynamic feasibility of conversion from MgH_(2)/CrO_(3) to MgO/Cr,which is well supported by the identification of Cr(0)in the powder by X ray photoelectron spectroscopy(XPS)*** high resolution transmission electron microscopy(HRTeM)and energy dispersive spectroscopy(eDS)we found evidence for the presence of 5 nm size Cr nanocrystals on the surface of MgO rock salt *** is also convincing ground to consider that MgO rock salt accommodates Cr in the *** observations support the argument that creation of active metal–metal dissolved rock salt oxide interface may be vital for improving the reactivity of MgH_(2),both for the improved storage of hydrogen and lithium.

关键词： Hydrogen storage Rechargeable batteries Binary hydrides Metal oxides Catalytic mechanism.

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Decision-Making and Management of Self-Care in Persons with Traumatic Spinal Cord Injuries: A Preliminary Study

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Journal of Behavioral and Brain Science 2024年第2期14卷 47-63页

作者： paul e. Plonski Jasmin Vassileva Ryan Shahidi paul B. Perrin William Carter Lance L. Goetz Amber Brochetti James M. Bjork Institute for Drug and Alcohol Studies Virginia Commonwealth University Richmond VA USA Richmond Veterans Affairs Medical Center Richmond VA USA Department of Psychiatry Virginia Commonwealth University Richmond VA USA Department of Psychology Virginia Commonwealth University Richmond VA USA Department of Physical Medicine and Rehabilitation Virginia Commonwealth University Richmond VA USA Department of Spinal Cord Injury Cleveland Veterans Affairs Medical Center Cleveland OH USA Department of Pharmacology and Toxicology Virginia Commonwealth University Richmond VA USA

Patients and physicians understand the importance of self-care following spinal cord injury (SCI), yet many individuals with SCI do not adhere to recommended self-care activities despite logistical supports. Neurobehavioral determinants of SCI self-care behavior, such as impulsivity, are not widely studied, yet understanding them could inform efforts to improve SCI self-care. We explored associations between impulsivity and self-care in an observational study of 35 US adults age 18 - 50 who had traumatic SCI with paraplegia at least six months before assessment. The primary outcome measure was self-reported self-care. In LASSO regression models that included all neurobehavioral measures and demographics as predictors of self-care, dispositional measures of greater impulsivity (negative urgency, lack of premeditation, lack of perseverance), and reduced mindfulness were associated with reduced self-care. Outcome (magnitude) sensitivity, a latent decision-making parameter derived from computationally modeling successive choices in a gambling task, was also associated with self-care behavior. These results are preliminary;more research is needed to demonstrate the utility of these findings in clinical settings. Information about associations between impulsivity and poor self-care in people with SCI could guide the development of interventions to improve SCI self-care and help patients with elevated risks related to self-care and secondary health conditions.

关键词： Spinal Cord Injury Self-Care Decision-Making Paraplegia Impulsive Behavior Health Care

Virtual brain twins: from basic neuroscience to clinical use

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National Science Review 2024年第05期 72-86页

作者： Huifang e.Wang paul Triebkorn Martin Breyton Borana Dollomaja Jean-Didier Lemarechal Spase Petkoski Pierpaolo Sorrentino Damien Depannemaecker Meysam Hashemi Viktor K.Jirsa Aix Marseille Université Institut National de la Santéet de la Recherche Médicale Institut de Neurosciences des Systèmes(INS) UMR1106 Service de Pharmacologie Clinique et Pharmacosurveillance AP–HM

Virtual brain twins are personalized, generative and adaptive brain models based on data from an individual's brain for scientific and clinical use. After a description of the key elements of virtual brain twins,we present the standard model for personalized whole-brain network models. The personalization is accomplished using a subject's brain imaging data by three means:(1) assemble cortical and subcortical areas in the subject-specific brain space;(2) directly map connectivity into the brain models, which can be generalized to other parameters; and(3) estimate relevant parameters through model inversion, typically using probabilistic machine learning. We present the use of personalized whole-brain network models in healthy ageing and five clinical diseases: epilepsy, Alzheimer's disease, multiple sclerosis, Parkinson's disease and psychiatric disorders. Specifically, we introduce spatial masks for relevant parameters and demonstrate their use based on the physiological and pathophysiological hypotheses. Finally, we pinpoint the key challenges and future directions.

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Acetabular cup size trends in total hip arthroplasty

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World Journal of Orthopedics 2024年第1期15卷 39-44页

作者： Daniel Patrick McKenna Alex Price Timothy McAleese Darren Dahly paul McKenna May Cleary Department of Trauma and Orthopaedics University Hospital WaterfordWaterford X91 ER8EIreland Department of epidemiology and Public Health University College CorkCork T12 XF62Ireland

BACKGROUND Total hip arthroplasty(THA)is a common procedure for end stage *** learning curve for THA is complex and *** of the most difficult skills to master is acetabular *** wish to identify if experience in arthroplasty leads to preservation of more bone *** To investigate if increasing surgeon experience will predict an ever decreasing acetabular cup *** A retrospective case series of four attending orthopaedic surgeons was *** uncemented elective total hip arthroplasties since appointment were selected for *** size of acetabular cup used was noted and logistic regression was used to identify if a trend to smaller cups *** A total of 1614 subjects were included with a mean age of 64 *** cups were on average 0.18mm smaller per year(95%confidence interval-0.25 to-0.11,Peon trends showed cup sizes to decrease 0.27 mm/year for surgeon A,0.02 mm/year for surgeon B,0.15 mm/year for surgeon C and 0.29 mm/year for surgeon *** of the four surgeons had a more pronounced trend to smaller cups for male subjects than their female *** We found increasing surgeon experience to be associated with an ever-decreasing acetabular cup *** acetabular cup size may act as a surrogate marker of surgical proficiency by virtue of decreased acetabular reaming.

关键词： Hip Arthroplasty Acetabulum Cup Learning