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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

Dose-response associations,physical activity intensity and mortality risk:A narrative review

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Journal of Sport and Health Science 2024年第1期13卷 24-29页

作者： Ulf Ekelund Miguel Adriano Sanchez-Lastra Knut Eirik Dalene jakob Tarp Department of Sport Medicine Norwegian School of Sport SciencesOslo 0806Norway Department of Chronic Diseases Norwegian Institute of Public HealthOslo 0213Norway Department of Special Didactics Faculty of Education and Sports SciencesUniversity of VigoPontevedra 36005Spain Well-Move Research Group Galicia-Sur Health Research Institute(SERGAS-UVIGO)Vigo 36213Spain

Physical activity is consistently associated with reduced mortality,decreased risk for non-communicable diseases,and improved mental health in observational *** controlled trials and observational Mendelian randomization studies support causal links between physical activity and health ***,the scarcity of evidence from randomized controlled trials,along with their inherent challenges like exposure contrasts,healthy volunteer biases,loss to follow-up,and limited real-world dose-response data,warrants a comprehensive *** review advocates synthesizing insights from diverse study designs to better understand the causal relationship between physical activity,mortality risk,and other health ***,it summarizes recent research since the publication of current physical activity *** observational studies utilizing device-measured physical activity underscore the importance of every minute of activity and suggest that all intensity levels confer health benefits,with vigorous-intensity potentially requiring lower volumes for substantial *** guidelines,informed by device-measured physical activity studies,may offer refined age-specific recommendations,emphasize vigorous-intensity physical activity,and include daily step counts as a simple,easily assessable metric using commercial wearables.

关键词： Accelerometers Non-communicable diseases Public health Sedentary behavior

Multifunctional SnO_(2) QDs/MXene Heterostructures as Laminar Interlayers for Improved Polysulfide Conversion and Lithium Plating Behavior

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Nano-Micro Letters 2024年第11期16卷 156-169页

作者： Shungui Deng Weiwei Sun Jiawei Tang Mohammad Jafarpour Frank Nüesch jakob Heier Chuanfang Zhang College of Materials Science and Engineering Sichuan UniversityChengdu 610065People’s Republic of China Laboratory for Functional Polymers Swiss Federal Laboratories for Materials Science and Technology(EMPA)Überlandstrasse 1298600 DübendorfSwitzerland Institute of Materials Science and Engineering Ecole Polytechnique Fédérale de Lausanne(EPFL)Station 121015 LausanneSwitzerland Key Laboratory of Quantum Materials and Devices of Ministry of Education School of PhysicsSoutheast UniversityNanjing 211189People’s Republic of China SEU‑FEI Nano‑Pico Center Key Laboratory of MEMS of Ministry of EducationSoutheast UniversityNanjing 210096People’s Republic of China

Poor cycling stability in lithium–sulfur(Li–S)batteries necessitates advanced electrode/electrolyte design and innovative interlayer *** catalysis has emerged as a promising approach,leveraging the adsorption and catalytic performance on lithium polysulfides(LiPSs)to inhibit LiPSs shuttling and improve redox *** this study,we report an ultrathin and laminar SnO_(2)@MXene heterostructure interlayer(SnO_(2)@MX),where SnO_(2) quantum dots(QDs)are uniformly distributed across the MXene *** combined structure of SnO_(2) QDs and MXene,along with the creation of numerous active boundary sites with coordination electron environments,plays a critical role in manipulating the catalytic kinetics of sulfur *** Li–S cell with the SnO_(2)@MX-modified separator not only demonstrates superior electrochemical performance compared to cells with a bare separator but also induces homogeneous Li deposition during *** a result,an areal capacity of 7.6 mAh cm^(-2) under a sulfur loading of 7.5 mg cm^(-2) and a high stability over 500 cycles are *** work demonstrates a feasible strategy of utilizing a laminar separator interlayer for advanced Li–S batteries awaiting commercialization and may shed light on the understanding of heterostructure catalysis with enhanced reaction kinetics.

关键词： Lithium-sulfur battery Heterogeneous catalysis Heterostructure Redox kinetics Lithium dendrites

Towards an enhanced understanding of the particle size effect on conversion/alloying lithium-ion anodes

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Materials Futures 2024年第1期3卷 150-164页

作者： jakob Asenbauer Dominik Horny Mayokun Olutogun Katrin Schulz Dominic Bresser Helmholtz Institute Ulm(HIU) 89081 UlmGermany Karlsruhe Institute of Technology(KIT) 76021 KarlsruheGermany Institute for Applied Materials(IAM) Karlsruhe Institute of Technology(KIT)76131 KarlsruheGermany Karlsruhe University of Applied Sciences 76133 KarlsruheGermany

Conversion/alloying materials(CAMs)represent a potential alternative to graphite as a Li-ion anode active material,especially for high-power *** far,however,essentially all studies on CAMs have been dealing with nano-sized particles,leaving the question of how the performance(and the de-/lithiation mechanism in general)is affected by the particle ***,we comparatively investigate four different samples of Zn_(0.9)Co_(0.1)O with a particle size ranging from about 30 nm to a few *** results show that electrodes made of larger particles are more susceptible to fading due to particle displacement and particle *** results also show that the conversion-type reaction in particular is affected by an increasing particle size,becoming less reversible due to the formation of relatively large transition metal(TM)and alloying metal nanograins upon lithiation,thus hindering an efficient electron transport within the initial particle,while the alloying contribution remains essentially *** generality of these findings is confirmed by also investigating Sn_(0.9)Fe_(0.1)O_(2) as a second CAM with a substantially greater contribution of the alloying reaction and employing Fe instead of Co as a TM dopant.

关键词： particle size conversion alloying anode lithium-ion battery

Influence of symmetric and asymmetric rolling on texture evolution of work-hardened AA 5xxx aluminium alloy

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Transactions of Nonferrous Metals Society of China 2024年

作者： Matja? Godec Stefan Zaefferer jakob Kraner ?rtomir Donik Irena Paulin Institute of Metals and Technology Max-Planck-Institut für Eisenforschung， Max-Planck-Strasse 1 Impol 2000 d.d.， Partizanska cesta 38

The textures and microstructures of hot- and cold-rolled sheets of an AA 5454 aluminium alloy were studied， with special attention paid to comparing the texture development for the symmetric and asymmetric cold rolling. Scanning electron microscopy with electron-backscatter diffraction was used to monitor the development of the microstructure in the differently deformed and additionally annealed samples. Details of the formations and transformations of individual texture components occurring during the rolling processes were observed and discussed. The average grain sizes， textures and mechanical properties were correlated and explained for the symmetric and asymmetric cold-rolled samples. The asymmetric rolling is beneficial in terms of deep drawability because it reduces the planar anisotropy of the annealed material due to the decrease of the Cube， Goss， Rotated Cube and η- fibre texture components and the same time strengthens X1- and X2-fibre texture components which are shear texture components and improve deep drawability. During the asymmetric cold rolling， the temperature increases due to friction， triggering recrystallisation processes and leading to larger grains. It was also confirmed that asymmetric cold rolling uses less rolling force and consequently less energy to produce a final material with better formability， particularly earing.

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Dielectric and physico-chemical behavior of single thermally thick wood blocks under microwave assisted pyrolysis

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Particuology 2024年第3期86卷 291-303页

作者： Nicole Vorhauer-Huget jakob Seidenbecher Supriya Bhaskaran Francesca Schenkel Lucas Briest Suresh Gopalkrishna Jan Barowski Andrea Dernbecher Liane Hilfert Ilona Rolfes Alba Dieguez-Alonso Otto von Guericke University Magdeburg Universitatsplatz 239106MagdeburgGermany Ruhr University Bochum Institute of Microwave SystemsUniversitatsstraβe 15044801BochumGermany

Pyrolysis of thermally thick beech wood blocks with a size of around 2.5×8×6 cm^(3)(width×length×height)was carried out in a lab scale microwave reactor with a frequency of 2.45 GHz,operated,both,at 300 W and 600 W under inert conditions,using N_(2) at around 400 mbar absolute *** microwave cavity had a size of 20×20×20 cm^(3).The specific energy supply referred to the untreated wood block was 4-8 W/g,with slight variations depending on the initial water *** mass loss and the reflected microwave power were in-situ monitored during the *** sample surface and chamber temperatures were measured with a pyrometer and a thermocouple,***-chemical and dielectric properties of the produced solids were investigated and compared to those of chars produced under conventional pyrolysis using the same raw *** is shown that the complex dielectric permittivity of the solid products changed drastically during the pyrolysis process,with increasing heating properties as the conversion process *** was easily achieved using 60o W without ***,300 W was not enough to achieve a high conversion degree,independently of the irradiation ***,together with the physico-chemical analyses of the solids,hinted to the importance of the transport kinetics in thermally thick materials,although further investigationis still required.

关键词： Microwave assistedpyrolysis Conventional pyrolysis Dielectric measurements Penetration depth Elemental analysis

Leisure-time physical activity and all-cause mortality and cardiovascular disease in adults with type 2 diabetes:Cross-country comparison of cohort studies

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Journal of Sport and Health Science 2024年第2期13卷 212-221页

作者： jakob Tarp Mengyun Luo Miguel Adriano Sanchez-Lastra Knut Eirik Dalene Borja del Pozo Cruz Mathias Ried-Larsen Reimar Wernich Thomsen Ulf Ekelund Ding Ding Department of Clinical Epidemiology Aarhus University&Aarhus University HospitalAarhus 8200Denmark Prevention Research Collaboration Sydney School of Public HealthThe University of SydneyCamperdownNSW 2006Australia Charles Perkins Centre the University of SydneyCamperdownNSW 2050Australia Department of Sports Medicine Norwegian School of Sports SciencesOslo 0806Norway Department of Special Didactics Faculty of Education and Sports SciencesUniversity of VigoPontevedra 36005Spain Well-Move Research Group Galicia Sur Health Research Institute(IIS Galicia Sur)SERGAS-UVIGOVigo 36213Spain Department of Chronic Diseases Norwegian Institute of Public HealthOslo 0473Norway Centre for Active and Healthy Ageing Department of Sports Science and Clinical BiomechanicsUniversity of Southern DenmarkOdense 5230Denmark Faculty of Education University of CadizCadiz 11519Spain Biomedical Research and Innovation Institute of Cadiz(INiBICA)Research Unit Puerta del Mar University HospitalUniversity of CadizCadiz 11009Spain The Centre of Inflammation and Metabolism&the Centre for Physical Activity Research RigshospitaletUniversity of CopenhagenCopenhagen 2100Denmark Department of Sports Science and Clinical Biomechanics University of Southern DenmarkOdense 5230Denmark

Purpose:This study aimed to quantify the dose-response association and the minimal effective dose of leisure-time physical activity(PA)to prevent mortality and cardiovascular disease in adults with type 2 ***:Cross-country comparison of 2 prospective cohort studies including 14,913 and 17,457 population-based adults with type 2 diabetes from the UK and *** leisure-time PA was self-reported and categorized by metabolic equivalent hours per week(MET-h/week)according to World Health Organization recommendations:none,below recommendation(>0-7.49 MET-h/week);at recommended level(7.5-14.9 MET-h/week);above recommendation(>15 MET-h/week).Mortality and cardiovascular disease data were obtained from national ***:During a median follow-up of 12.4 and 9.7 years,in the UK and China cohorts,repectively,higher levels of leisure-time PA were inversely associated with all-cause(1571 and 2351 events)and cardiovascular mortality(392 and 1060 events),mostly consistent with a linear dose-response *** below,at,and above recommendations,compared with no activity,yielded all-cause mortality hazard ratios of0.94(95%confidence interval(95%CI):0.79-1.12),0.90(95%CI:0.74-1.10),and 0.85(95%CI:0.70-1.02)in British adults and 0.87(95%CI:0.68-1.10),0.88(95%CI:0.74-1.03),and 0.77(95%CI:0.70-0.85)in Chinese *** with cardiovascular mortality were more pronounced in British adults(0.80(95%CI:0.58-1.11),0.75(95%CI:0.52-1.09),and 0.69(95%CI:0.48-0.97))but less pronounced in Chinese adults(1.06(95%CI:0.76-1.47),1.01(95%CI:0.80-1.28),and 0.79(95%CI:0.69-0.92)).PA at recommended levels was not associated with lower rates of major adverse cardiovascular events(2345 and 4458 events).Conclusion:Leisure-time PA at the recommended levels was not convincingly associated with lower mortality and had no association with risk of major adverse cardiovascular events in British or Chinese adults with type 2 ***-time PA above current recom

关键词： Complications Epidemiology Exercise Prevention

Intraoperative application of three-dimensional printed guides in total hip arthroplasty: A systematic review

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World Journal of Orthopedics 2024年第7期15卷 660-667页

作者： Tim P Crone Bart M W Cornelissen jakob Van Oldenrijk Pieter Koen Bos Ewout S Veltman Department of Orthopedic Surgery and Sports Medicine Erasmus Medical CenterRotterdam 3015 GDNetherlands Department of Oral and Maxillofacial Surgery Erasmus Medical CenterRotterdam 3015 GDNetherlands

BACKGROUND Acetabular component positioning in total hip arthroplasty(THA)is of key importance to ensure satisfactory post-operative outcomes and to minimize the risk of *** majority of acetabular components are aligned freehand,without the use of navigation *** specific instruments(PSI)and three-dimensional(3D)printing of THA placement guides are increasingly used in primary THA to ensure optimal *** To summarize the literature on 3D printing in THA and how they improve acetabular component *** PubMed was used to identify and access scientific studies reporting on different 3D printing methods used in *** studies with 236 hips in 228 patients were *** studies could be divided into two main categories;3D printed models and 3D printed *** 3D printing in THA helped improve preoperative cup size planning and post-operative Harris hip scores between intervention and control groups(P=0.019,P=0.009).Otherwise,outcome measures were heterogeneous and thus difficult to *** overarching consensus between the studies is that the use of 3D guidance tools can assist in improving THA cup positioning and reduce the need for revision THA and the associated *** The implementation of 3D printing and PSI for primary THA can significantly improve the positioning accuracy of the acetabular cup component and reduce the number of complications caused by malpositioning.

关键词： Total hip arthroplasty Three-dimensional printing Hip replacement surgery Three-dimensional planning Surgical guides

Device-measured physical activity and sedentary time in the Nordic countries:A scoping review of population-based studies

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Journal of Sport and Health Science 2024年第5期13卷 650-660页

作者： Ing-Mari Dohrn jakob Tarp Jostein Steene-Johannessen Tommi Vasankari Maria Hagströmer Division of Physiotherapy Department of NeurobiologyCare Sciences and SocietyKarolinska Institutet14183 HuddingeSweden Department of Sports Medicine Norwegian School of Sports Sciences0806 OsloNorway UKK Institute for Health Promotion Research 33500 TampereFinland Faculty of Medicine and Health Technology Tampere University33100 TampereFinland Academic Primary Health Care Centre Region Stockholm13365 StockholmSweden

Purpose:The purpose of this scoping review was to summarize and describe the methodology and results from population-based studies of physical activity and sedentary time measured with devices in the Nordic countries(Denmark,Finland,Iceland,Norway,and Sweden)and published in 2000 or ***:A systematic search was carried out in PubMed and Web of Science in June 2023 using predefined search ***:Fourteen unique research projects or surveillance studies were ***,2 surveillance studies published by national agencies were included,resulting in a total of 16 studies for *** surveillance systems exist in Finland and Norway,with regular survey waves in school-aged children/adolescents and *** Denmark,recent nationally representative data have been collected in school children *** far,Sweden has no regular national surveillance system using device-based data *** studies were found from *** first study was conducted in 2001 and the most recent in 2022,with most data collected from 2016 to *** studies included children/adole scents 6-18 years,no study included *** total 11 studies included adults,of which 8 also covered older *** study focused specifically on older *** analytical sample size ranged from 205 to 27,*** methodology is presented,such as information on sampling strategy,device type and placement,wear protocols,and physical activity classification *** of physical activity and sedentary time in children/adolescents,adults,and older adults across the Nordic countries are ***:A growing implementation of device-based population surveillance of physical activity and sedentary behavior in the Nordic countries has been *** variety of devices,placement,and data procedures both within and between the Nordic countries highlights the challenges when it comes to comparing study outcomes as well as the need for more standa

关键词： Accelerometer Light intensity Moderate-vigorous intensity Surveillance Wearable devices