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Error Estimates for Finite-Element Navier-Stokes Solvers without Standard Inf-Sup Conditions

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Chinese Annals of Mathematics,Series B 2009年第6期30卷 743-768页

作者： robert l.pego Department of Mathematical Sciences and Center for Nonlinear Analysis Carnegie Mellon University PittsburghPA 15213USA

The authors establish error estimates for recently developed finite-element methods for incompressible viscous flow in domains with no-slip boundary *** methods arise by discretization of a well-posed extended Navier-Stokes dynamics for which pressure is determined from current velocity and force *** methods use C1 elements for velocity and C0 elements for pressure.A stability estimate is proved for a related finite-element projection method close to classical time-splitting methods of Orszag,Israeli,DeVille and Karniadakis.

关键词： Time-dependent incompressible flow Projection method Backward facing step Driven cavity Stokes pressure leray projection Obtuse corner Recycling

Assessment of portable FTIR and Raman spectroscopy for the detection of 2,3-dimethyl-2,3-dinitrobutane(DMDNB)in plastic explosives

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Defence Technology（防务技术） 2024年第4期34卷 11-18页

作者： Jacky Cailes robert Dunsmore Kathryn l.linge ChemCentre PO Box 1250PerthAustralia

The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of ***,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the *** this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within *** both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB *** all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex *** testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the ***,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for *** is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.

关键词： Explosive ICAO taggants 2,3-Dimethyl-2,3-dinitrobutane(DMDNB) Fourier transform infrared(FTIR) Raman

The influence of various grease compositions and silver nanoparticle additives on electrically induced rolling-element bearing damage

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Friction 2024年第4期12卷 796-811页

作者： Samuel BOND robert l.JACKSON German MIllS Department of Chemistry and Biochemistry Auburn UniversityAuburn 36849-5412USA Department of Mechanical Engineering Auburn UniversityAuburn 36849-5412USA

leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films,but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact *** findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver(Ag)*** rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without *** forces and electrical resistance were monitored continuously during the tests;surface changes were characterized by means of optical spectroscopy,stylus profilometry,and scanning electron microscopy(SEM)including compositional analysis using energy dispersive spectroscopy(EDS).The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear ***-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon *** findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles;some greases containing other additives exhibit a similar,although less pronounced,effect.

关键词： electric motor bearings wheel bearings electric vehicles arcing electrically induced bearing damage pitting leakage current stray current

Science and reflections: With some thoughts to young applied scientists and engineers

维普期刊数据库评论

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维普期刊数据库

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Earthquake Science 2024年第5期37卷 459-493页

作者： robert l Nowack Department of Earth Atmospheric and Planetary SciencesPurdue UniversityWest LafayetteIN47906USA

I provide some science and reflections from my experiences working in geophysics,along with connections to computational and data sciences,including recent developments in machine learning.I highlight several individuals and groups who have influenced me,both through direct collaborations as well as from ideas and insights that I have learned *** my reflections are rooted in geophysics,they should also be relevant to other computational scientific and engineering fields.I also provide some thoughts for young,applied scientists and engineers.

关键词： geophysics computational and data science applied science and engineering

Epidemiology of insertional and midportion Achilles tendinopathy in runners:A prospective cohort study

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Journal of Sport and Health Science 2024年第2期13卷 256-263页

作者： Wenbo Chen Kyra l.A.Cloosterman Sita M.A.Bierma-Zeinstra Marienke van Middelkoop robert-Jan de Vos Department of Orthopaedic Surgery and Sports Medicine Erasmus MC University Medical CenterRotterdam 3015GDthe Netherlands Department of General Practice Erasmus MC University Medical CenterRotterdam 3015GDthe Netherlands Department of Sports Medicine Huashan HospitalFudan UniversityShanghai 200040China

Background:Achilles tendinopathy(AT)is a common problem among *** is only limited evidence for risk factors for AT,and most studies have not defined the AT *** study has compared the incidence and risk factors between insertional AT and midportion AT,though they are considered *** study aimed to assess incidence and risk factors of AT based on data from a large prospective *** secondary aim was to explore differences in risk factors between insertional and midportion ***:Participants were recruited from among registered runners at registration for running *** were completed at baseline,1 month before the event,1 week before the event,and 1 month after the *** concerning demographics,training load,registered events,and running-related injuries were collected at *** follow-up questionnaires collected information about new injuries.A pain map was used to diagnose midportion and insertional *** primary outcome was the incidence of *** logistic regression analysis was applied to identify risk factors for the ***:We included 3379 participants with a mean follow-up of 20.4 *** incidence of AT was 4.2%.The proportion of insertional AT was 27.7%and of midportion AT was 63.8%;the remaining proportion was a combined type of insertional and midportion *** had a significantly higher incidence(5%,95%confidence interval(95%CI):4.1%-6.0%)than women(2.8%,95%CI:2.0%-3.8%).AT in the past12 months was the most predominant risk factor for new-onset AT(odds ratio(OR)=6.47,95%CI:4.27-9.81).This was similar for both subcategories of AT(insertional:OR=5.45,95%CI:2.51-11.81;midportion:OR=6.96,95%CI:4.24-11.40).Participants registering for an event with a distance of 10/10.55 km were less likely to develop a new-onset AT(OR=0.59,95%CI:0.36-0.97)or midportion AT(OR=0.47,95%CI:0.23-0.93).Higher age had a significant negative association with insertional AT(OR=0.97,95%CI:0.9

关键词： Achilles tendon injury Incidence Risk factor Running-related injury

Public health importance of light intensity physical activity

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Journal of Sport and Health Science 2024年第5期13卷 674-675页

作者： robert Ross Ian Janssen Mark S.Tremblay School of Kinesiology and Health Studies Queen’s UniversityKingstonON K7L 3N6Canada School of Medicine Division of Endocrinology and MetabolismQueen’s UniversityKingstonON K7L 3N6Canada Healthy Active living and Obesity Research Group Children’s Hospital of Eastern Ontario Research InstituteOttawaON K1H 8L1Canada Department of Pediatrics University of OttawaOttawaON K1H 8L1Canada

*** intensity physical activity(PA)benefits health PA guidelines worldwide recommend that adults accumulate 150 min of moderate intensity or 75 min of vigorous intensity PA(moderate-to-vigorous PA(MVPA))weekly to achieve health benefits.1-3 Absent from these guidelines are recommendations for light intensity PA(lPA,e.g.,walking at a leisurely pace of 3 km/h or less,equivalent to 1.5-2.9 metabolic equivalents).

关键词： intensity light benefits

Effects of soil metal(loid)s pollution on microbial activities and environmental risks in an abandoned chemical smelting site

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Journal of Environmental Sciences 2024年第9期143卷 60-70页

作者： Hao li Jun Yao Jianli liu Ning Min Geoffrey Sunahara Dongyang Men robert Duran School of Water Resources and Environment Research Center of Environmental Science and EngineeringChina University of Geosciences(Beijing)Beijing 100083China Department of Natural Resource Sciences McGill University21111Lakeshore DriveSte-Anne-de-BellevueQuebecH9X 3V9Canada Equipe Environnement et Microbiologie MELODY groupUniversitéde Pau et des Pays de l’AdourE2S-UPPAIPREM UMR CNRS 5254BP 115564013 Pau CedexFrance

Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological *** samples were collected from different depths(0 to 13 m)and analyzed for metal(loid)s content and fractionation,as well as microbial *** potential ecological risk indices for the different soil depths(ordered from high to low)were:1 m(D-1)>surface(S-0)>5 m(D-5)>13 m(D-13)>9 m(D-9),ranging between 1840.65-13,089.62,and representing extremely high environmental risks,of which Cd(and probably not arsenic)contributed to the highest environmental risk.A modified combined pollution risk index(MCR)combining total content and mobile proportion of metal(loid)s,and relative toxicities,was used to evaluate the degree of contamination and potential environmental *** the near-surface samples(S-0 and D-1 layers),the MCR considered that As,Cd,Pb,Sb,and Zn achieved high and alarming degrees of contamination,whereas Fe,Mn,and Ti were negligible or low to moderate pollution *** microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity *** analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics(pl metabolic activity in the D-1 layer was low presumably due to heavy metal *** activity indicators and microcalorimetric growth rate(k)measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites.

关键词： Abandoned chemical smelting sites Microbial activities Modified combined pollution risk Microcalorimetry Enzymatic activities

Excess dietary lys reduces feed intake, stimulates jejunal CCK secretion and alters essential and non‑essential blood AA profile in pigs

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Journal of Animal Science and Biotechnology 2024年第3期15卷 1336-1346页

作者： Maximiliano Muller Elout Van liefferinge Alan Tilbrook robert van Barneveld Eugeni Roura Centre for Nutrition and Food Sciences Queensland Alliance for Agriculture and Food InnovationThe University of QueenslandBrisbaneQueensland 4072Australia laboratory of Animal Nutrition and Animal Product Quality(lANUPRO) Department of Animal Sciences and Aquatic EcologyGhent University339000 GhentFlandersBelgium Centre for Animal Science Queensland Alliance for Agriculture and Food Innovation and the School of Veterinary ScienceThe University of QueenslandBrisbaneQueensland 4072Australia SunPork Group BrisbaneQueensland 4009Australia

Background Commercial diets are frequently formulated to meet or exceed nutrient levels including those of lim-iting essential amino acids(AA)covering potential individual variations within the ***,the provision of dietary excess of AA,such as lys,may lead to reduced appetite and growth in *** mechanisms modulat-ing these responses have not been extensively *** study evaluated the effect of lys dietary excesses on performance and satiety biomarkers in post weaning *** Twenty-four pigs aged 21 d and weighing 6.81±0.12kg(mean±SEM)were individually housed and offered 1 of 4 dietary treatments for 3weeks:a diet containing a standardized ileal digestible lys reaching 100%(T0),120%(T1),150%(T2)or 200%(T3)of the NRC(2012)*** the end of the experiment,blood samples from the cephalic vein of the T0 and T3 groups were obtained for AA *** addition,primary intestinal cultures from T0 pigs were used,following their humane killing,to evaluate the effect of lys on gut hormone secretion and AA sensors gene expression under ex vivo *** Feed intake was linearly reduced(Plevels of lys during the third-and first-week post weaning,*** con-centration(Plutamate receptor 1 and the solute carrier family 7 member 2(Pl jejunum tissues incubated with lys at 20mmol/l when compared to the control(lys 0mmol/l).Plasma lys and Glu(Plasma levels of His,Val,Thr,leu(Pln(Plower in T3 than T0 *** The present results confirm that excess dietary lys inhibits hunger in ***,the results provide evidence of pre-and post-absorptive mechanisms modulating these *** dietary excesses should be nar-rowed,when possible,to avoid negative effects of

关键词： Amino acid Blood Cholecystokinin Feed intake lysine Pig Satiety

Three-stage pyrolysis–steam reforming–water gas shift processing of household,commercial and industrial waste plastics for hydrogen production

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Waste Disposal and Sustainable Energy 2024年第1期6卷 25-37页

作者： Rayed Alshareef robert Sait-Stewart Mohamad A.Nahil Paul T.Williams School of Chemical and Process Engineering University of LeedsLeedsLS29JTUK

Five common single plastics and nine different household,commercial and industrial waste plastics were processed using a three-stage(i)pyrolysis,(ii)catalytic steam reforming and(iii)water gas shift reaction system to produce *** of plastics produces a range of different hydrocarbon species which are subsequently catalytically steam reformed to produce H_(2)and CO and then undergo water gas shift reaction to produce further H_(2).The process mimics the commercial process for hydrogen production from natural *** of the single polyalkene plastics(high-density polyethylene(HDPE),low-density polyethylene(lDPE),and polypropylene(PP))produced similar H_(2)yields between 115 mmol and 120 mmol per gram *** though PS produced an aromatic product slate from the pyrolysis stage,further stages of reforming and water gas shift reaction produced a gas yield and composition similar to that of the polyalkene plastics(115 mmol H_(2)per gram plastic).PET gave significantly lower H_(2)yield(41 mmol per gram plastic)due to the formation of mainly CO,CO_(2)and organic acids from the pyrolysis stage which were not conducive to further reforming and water gas shift reaction.A mixture of the single plastics typical of that found in municipal solid waste produced a H_(2)yield of 102 mmol per gram *** the gas yields and composition from the single plastics enabled an estimation of the yields from a simulated waste plastic mixture and a‘real-world’waste plastic mixture to be *** different household,commercial and industrial waste plastic mixtures produced H_(2)yields between 70 mmol and 107 mmol per gram *** H_(2)yield and gas composition from the single waste plastics gave an indication of the type of plastics in the mixed waste plastic samples.

关键词： Waste plastic Hydrogen Catalyst Pyrolysis reforming Water gas shift