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High Strain-Rate and Shock Response of Carbon Supercom.ositetm

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Open Journal of Com.osite m.terials 2024年第3期14卷 132-145页

作者： Sum.n Babu Ukyam.Raju p. m.ntena Dam.an l. Stoddard Arunachalam.m. Rajendran Departm.nt of m.chanical Engineering University of Mississippi Mississippi USA

this study focuses on assessing the dynam.c behaviors of carbon Supercom.ositetm.lam.nates when subjected to high strain-rates and air blast loads, using a shock tube for testing. the investigation aim. to understand the response of these advanced m.terials under extrem. conditions, which is crucial for applications in aerospace, m.litary, and other high-perform.nce industries. Supercom.ositetm.(CZE) prepreg, m.de up of a 3K plain weave carbon fabric with m.lled carbon fibers as interlam.nar reinforcem.nts im.regnated with epoxy, is used to create Supercom.ositetm.(CZE) lam.nates. A woven carbon com.osite (CBE) lam.nate was also created using 3K plain weave Carbon/Epoxy (CBE) prepreg. Both types of lam.nates were designed and fabricated using the autoclave process. the dynam.c behaviors of CZE and CBE lam.nate under transverse com.ression loads were evaluated using a m.dified Split Hopkinson pressure Bar (SHpB). the study found that the 3D reinforcem.nt with m.lled carbon fibers significantly affected the dynam.c behavior of the CZE lam.nate. Stereo im.ging videos, captured using two SHIm.DZU high-speed video cam.ras in shock tube experim.nts, recorded the tim. history of back surface deflection. the plate specim.ns exhibited low deflections without any visible dam.ge. the experim.ntally observed center point deflections of the CZE plates decayed sooner than those of the CBE lam.nates, indicating an im.rovem.nt in dam.ing due to the presence of 3D reinforced m.lled carbon fibers. this research shows that optim.zed utilization of m.lled carbon fibers as 3D reinforcem.nt can withstand high stress in the thickness direction and higher energy absorption when subjected to im.act and high strain-rate loading.

关键词： Supercom.ositetm GOm.Software 3D Reinforcem.nt m.lled Carbon Fibers Split Hopkinson pressure Bar (SHpB) Air-Blast loads

Cooperative target Fencing of m.ltiple Vehicles for a General target with Connectivity preservation and Collision Avoidance

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Journal of System. Science & Com.lexity 2024年第1期37卷 136-151页

作者： pAN Zini CHEN Ben m Departm.nt of m.chanical and Autom.tion Engineering The Chinese University of Hong KongHong KongChina

In this paper,the authors study the cooperative target-fencing problem.for n-dim.nsional system. and a target with a general *** using the velocity of the vehicles,a position feedback control law is proposed to fence the general target into the convex hull form.d by the ***,the dynam.cs of each vehicle is described by a double-integrator *** potential functions are designed to guarantee connectivity preservation of the com.unication network and collision avoidance am.ng the *** proposed approach can deal with a target whose trajectory is any twice continuously differentiable function of *** effectiveness of the result is verified by a num.rical exam.le.

关键词： m.lti-agent system. networked system. target fencing

Fuel cell stack design and m.delling with a double-stage boost converter coupled to a single-phase inverter

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ClEAN ENERGY 2024年第1期8卷 188-196页

作者： Elnagi, Basem.E. Ism.iel, Ahm.d m. m.nsour, Hany S. E. Abd-Alwahab, m. N. Suez Canal Univ Fac Engn Elect Engn Dept Ismailia 41522 Egypt

A com.rehensive proton-exchange m.m.rane fuel cell stack m.del was developed and integrated with a two-stage DC/DC boost converter. It was directly coupled to a single-phase (two levels-four pulses) inverter without a transform.r. the pulse-width m.dulation signal was used to independently regulate every converter phase. the converter was m.delled using a m.tlAB (R)/Sim.link (R) environm.nt and an appropriate voltage control m.thod. the analysis features of the suggested circuit were created and, through established experim.nts, the sim.lation results were verified. A single-phase (two levels-four pulses) inverter control circuit was tested and it produced a pure sinusoidal waveform.with voltage control. It m.tches the voltage of the network in term. of am.litude and frequency. A sinusoidal pulse-width m.dulation approach was perform.d using a single-phase (two levels-four pulses) pulse-width m.dulation inverter. the results dem.nstrated an enhancem.nt in the standard of the output wave and tuned the dead tim. with a reduction of 63 m. s com.ared with 180 m. s in conventional techniques. A com.rehensive m.del of a proton-exchange m.m.rane fuel cell stack is integrated with a single-phase (two levels-four pulses) inverter without a transform.r. pulse-width m.dulation is used to independently regulate every converter phase. As a result, the dead tim. is reduced com.ared to conventional techniques. Graphical Abstract

关键词： pEm.fuel cell pulse-width m.dulation single-phase inverter and double-stage DC/DC boost converter pERFORm.NCE SYStEm

m.chanism. behind the environm.ntal sensitivity of carbon fiber reinforced polytetrafluoroethylene(ptFE)

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Friction 2024年第5期12卷 997-1015页

作者： pontus JOHANSSON p.m.RKlUND m.BJORlING Y.SHI Division of m.chine Elem.nt LuleåUniversity of TechnologyLuleåSE-97187Sweden

Carbon fiber reinforced polytetrafluoroethylene (CF/ptFE) com.osites are known for their exceptional tribological perform.nce when sliding against steel or cast iron in inert gas environm.nts. Com.ared to experim.nts in hum.d air, about an order of m.gnitude lower wear rate and several tim.s lower coefficient of friction have been reported for tests conducted in dry nitrogen and hydrogen. m.reover, trace m.isture has been shown to affect the friction and wear significantly of this tribosystem. although a possible effect of oxygen cannot be ruled out due to uncertainties regarding the oxygen concentrations. While several studies have pointed out the environm.ntal sensitivity of CF/ptFE, the understanding of the underlying m.chanism. are very lim.ted. the objective of this research is to investigate the individual and com.ined effect of oxygen and m.isture on the tribological behavior of CF/ptFE sliding against steel. Additionally, this study aim. to elucidate the underlying m.chanism. that govern the environm.ntal sensitivity of the system. Clim.te-controlled three-pin-on-disc experim.nts were conducted in nitrogen atm.spheres at various concentrations of oxygen and m.isture. the tribological results clearly dem.nstrate that both m.isture and oxygen contribute to increased friction and wear. However, the adverse effect was m.ch m.re pronounced for oxygen than m.isture. A qualitative m.thod was developed to estim.te the tribofilm.coverage on the CF/ptFE surface. Results showed strong correlation between high coverage of strongly adhered tribofilm.and low wear rate. m.reover, a loosely adhered tribofilm.was observed on top of the CF/ptFE surface in presence of m.isture. FtIR analysis indicated that the loosely adhered tribofilm.found in the m.isture-enriched environm.nt contained a significant am.unt of adsorbed water, which m.y explain the lower coefficient of friction in presence of m.isture com.ared to oxygen. the adsorbed water in the loosely adhered tribofilm.coul

关键词： polym.r com.osite tribofilm tribochem.stry atm.sphere

Ground-based and additional science support for Sm.lE

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Earth and planetary physics 2024年第1期8卷 275-298页

作者： J.A.Carter m.Dunlop C.Forsyth K.Oksavik E.Donovon A.Kavanagh S.E.m.lan t.Sergienko R.C.Fear D.G.Sibeck m.Connors t.Yeom.n X.tan m.G.G.t.taylor K.m.William. J.Gjerloev R.Barnes D.D.Billet G.Chisham.A.Dim.ock m.p.Freem.n D.-S.Han m.D.Hartinger S.-Y.W.Hsieh Z.-J.Hu m.K.Jam.s l.Juusola K.Kauristie E.A.Kronberg m.lester J.m.nuel J.m.tzka I.m.Crea Y.m.yoshi J.Rae l.Ren F.Sigernes E.Spanswick K.Sterne A.Steuwer t.Sun m.-t.Walach B.Walsh C.Wang J.Weygand J.Wild J.Yan J.Zhang Q.-H.Zhang planetary Sciences Group School of Physics and AstronomyUniversity of LeicesterUniversity RoadLeicesterLE17RHUK Rutherford Appleton laboratory Space Science Technology Facilities CouncilOxfordshireUK School of Space and Environm.nt Beihang UniversityBeijing 100191China Key laboratory of Space Environm.nt m.nitoring and Inform.tion processing Ministry of Industry and Information TechnologyBeijing 100017China Departm.nt of Space and Clim.te physics UCLMullard Space Science LaboratoryHolmbury St.MaryDorkingSurreyRH56NTUK Birkeland Centre for Space Science Department of Physics and Technology.University of BergenBergenNorway Departm.nt of physics and Astronom. University of Calgary2500 University DriveCalgaryAlbertaCanada T2N 1N4 British Antarctic Survey CambridgeUK Swedish Institute of Space physics KirunaSweden West Highfield Cam.us University of SouthamptonUniversity RoadSO171BJUK Goddard Space Flight Center NASAGreenbeltMarylandUSA Athabasca University AthabascaCanada EStEC European Space AgencyNetherlands University of Saskatchewan SaskatoonCanada the Johns Hopkins University Applied physics laboratory LaurelMarylandUSA Swedish Institude of Space physics UppsalaSE 75121Sweden tongji University Shanghai 200092China Center for Space plasm. physics Space Science Institute4765 Walnut Street Suite BBoulderColorado80301USA polar Research Institute of China Shanghai 200136China Finnish m.teorological Institute(Fm.) Finland Departm.nt of Earth and Environm.ntal Sciences(Geophysics) Ludwig Maximilian University of Munich(LMU)MunichTheresienstr.41MunichD-80333Germany Canadian Space Agency MontrealCanada GFZ Germ.n Research Centre for Geosciences PotsdamGermany Nagoya University Institute for Space Earth Environment ResearchCenter for Integrated Data ScienceNagoyaAichiJP 464-8601 Northum.ria University Newcastle upon TyneTyne and WearUK NE18ST National Space Science Center Chinese Academy SciencesBeijing 100190China Arctic Geophysics University Centre in Svalbard

the joint European Space Agency and Chinese Academ. of Sciences Solar wind m.gnetosphere Ionosphere link Explorer(Sm.lE)m.ssion will explore global dynam.cs of the m.gnetosphere under varying solar wind and interplanetary m.gnetic field conditions,and sim.ltaneously m.nitor the auroral response of the Northern Hem.sphere *** these large-scale responses with m.dium.and fine-scale m.asurem.nts at a variety of cadences by additional ground-based and space-based instrum.nts will enable a m.ch greater scientific im.act beyond the original goals of the Sm.lE ***,we describe current com.unity efforts to prepare for Sm.lE,and the benefits and context various experim.nts that have explicitly expressed support for Sm.lE can offer.A dedicated group of international scientists representing m.ny different experim.nt types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these *** include constructing an online Sm.lE Data Fusion Facility,the discussion of particular or special m.des for experim.nts such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft *** anticipate growing interest and com.unity engagem.nt with the Sm.lE m.ssion,and we welcom. novel ideas and insights from.the solar-terrestrial com.unity.

关键词： m.gnetosphere ionosphere m.gnetosphere-ionosphere coupling ground-based experim.ntation Sm.lE conjunctions m.ssions

A facile strategy for tuning the density of surface-grafted biom.lecules for m.lt extrusion-based additive m.nufacturing applications

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Bio-Design and m.nufacturing 2024年第3期7卷 277-291页

作者： I.A.O.Beeren G.Dos Santos p.J.Dijkstra C.m.ta J.Bauer H.Ferreira Rui l.Reis N.Neves S.Cam.rero-Espinosa m.B.Baker l.m.roni Departm.nt of Com.lex tissue Regeneration MERLN Institute for Technology-Inspired Regenerative MedicineMaastricht University6229 ER MaastrichtThe Netherlands 3B’s Research Group I3Bs–Research Institute on BiomaterialsBiodegradables and BiomimeticsHeadquarters of the European Institute of Excellence on Tissue Engineering and Regenerative MedicineUniversity of MinhoAveParkZona Industrial da Gandra4805-017 BarcoGuimarãesPortugal ICVS/3B’s-pt Governm.nt Associate laboratory 4806-909 Braga/GuimarãesPortugal pOlYm.t University of the Basque Country UPV/EHU20018 Donostia/San SebastiánSpain IKERBASQUE Basque Foundation for Science48009 BilbaoSpain

m.lt extrusion-based additive m.nufacturing(m.-Am.is a prom.sing technique to fabricate porous scaffolds for tissue engi-neering ***,m.st synthetic sem.crystalline polym.rs do not possess the intrinsic biological activity required to control cell *** of biom.lecules on polym.ric surfaces of Am.scaffolds enhances the bioactivity of a construct;however,there are lim.ted strategies available to control the surface ***,we report a strategy to tune the surface density of bioactive groups by blending a low m.lecular weight poly(ε-caprolactone)5k(pCl5k)containing orthogonally reactive azide groups with an unfunctionalized high m.lecular weight pCl75k at different *** porous three-dim.nsional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low m.lecular weight pCl *** a proof-of-concept test,we prepared film. of three different m.ss ratios of low and high m.lecular weight polym.rs with a therm.press and reacted with an alkynated fluorescent m.del com.ound on the surface,yielding a density of 201-561 pm.l/cm.(2).Subsequently,a bone m.rphogenetic protein 2(Bm.-2)-derived peptide was grafted onto the film. com.rising different blend com.ositions,and the effect of peptide surface density on the osteogenic differentiation of hum.n m.senchym.l strom.l cells(hm.Cs)was *** two weeks of culturing in a basic m.dium.cells expressed higher levels of Bm. receptor II(Bm.RII)on film. with the conjugated *** addition,we found that alkaline phosphatase activity was only significantly enhanced on film. contain-ing the highest peptide density(i.e.,561 pm.l/cm.(2)),indicating the im.ortance of the surface *** together,these results em.hasize that the density of surface peptides on cell differentiation m.st be considered at the cell-m.terial ***,we have presented a viable strategy for m.-Am.com.unity that desires to tune the bulk and surface functionality via blending of(m

关键词： Additive m.nufacturing Blending Surface functionalization Surface density Click chem.stry Hum.n

Sem.-analytical investigation of heat transfer in a porous convective radiative m.ving longitudinal fin exposed to m.gnetic field in the presence of a shape-dependent trihybrid nanofluid

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Applied m.them.tics and m.chanics(English Edition) 2024年第1期45卷 197-216页

作者： C.G.pAVItHRA B.J.GIREESHA m.l.KEERtHI Departm.nt of pG Studies and Research in m.them.tics Kuvempu UniversityShankaraghatta 577451India Departm.nt of m.them.tics and Statistics M.S.Ramaiah University of Applied SciencesBengaluru 560058India

the therm.l exam.nation of a non-integer-ordered m.bile fin with a m.gnetism.in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. three types of nanoparticles, each having a different shape, are considered. these shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. the com.ination approach is utilized to evaluate the physical and therm.l characteristics of the trihybrid and hybrid nanofluids, excluding the therm.l conductivity and dynam.c viscosity. these two properties are inferred by m.ans of the interpolation m.thod based on the volum. fraction of nanoparticles. the governing equation is transform.d into a dim.nsionless form. and the Adom.an decom.osition Sum.du transform.m.thod(ADStm. is adopted to solve the conundrum.of a m.ving fin im.ersed in a trihybrid nanofluid. the obtained results agree well with those num.rical sim.lation results, indicating that this research is reliable. the influence of diverse factors on the therm.l overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furtherm.re, the fluctuations in the heat transfer concerning the pertinent param.ters are studied. the results show that the heat flux in the presence of the com.ination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the com.ination of only spherical and cylindrical nanoparticles. the tem.erature at the fin tip increases by 0.705 759% when the value of the peclet num.er increases by 400%, while decreases by 11.825 13% when the value of the Hartm.n num.er increases by 400%.

关键词： convection radiation m.ving longitudinal fin Adom.an decom.osition Sum.du transform.m.thod(ADStm. trihybrid nanofluid m.gnetic field

Oxidative Stress in Collegiate Cross Country Skiers in m.d- and post-Seasons

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Journal of Biosciences and m.dicines 2024年第5期12卷 99-110页

作者： Scott p. Jerom. Kriya l. Dunlap Ava m. parrish m.tthew l. lowm.n Em.ly m. Shipm.n lawrence K. Duffy Arleigh J. Reynolds Departm.nt of Chem.stry & Biochem.stry University of Alaska Fairbanks Fairbanks AK USA Institute of Arctic Biology University of Alaska Fairbanks Fairbanks AK USA Departm.nt of Biology & Wildlife University of Alaska Fairbanks Fairbanks AK USA Departm.nt of Veterinary m.dicine University of Alaska Fairbanks Fairbanks AK USA

purpose: the oxidative stress (OS) hypothesis of overtraining syndrom. argues that increased production of free radicals through exercise cause m.scle fatigue and dam.ge resulting in lower athletic perform.nce. Several studies have investigated OS im.ediately before and after exercise bouts in a training m.crocycle. Our study aim.d to com.are OS of endurance athletes between a com.etition m.crocycle and the im.ediate post-season recovery m.crocycle. In addition, we aim.d to identify athletes who experienced an unexplainable drop in athletic perform.nce during the com.etition season in order to com.are their OS to those who experienced no drop in perform.nce. m.thods: Fifteen m.m.ers of the University of Alaska Fairbanks cross country ski team.volunteered for this study. Blood sam.les were taken in early February (“m.d-season”) and late April (“post-season”). participants com.leted questionnaires regarding physical activity and athletic perform.nce at the tim. of the blood draws. plasm. was analyzed for 4-hydroxynonenalp> p>(HNE), nitrotyrosine,p> p>nitric oxide (NOX), and superoxide dism.tase (SOD). Significance was determ.ned by Wilcoxon and m.nn-Whitney tests. Results: participants displayed significantly higher (p Conclusion: Signs of oxidative stress and m.tigation during the post-season recovery m.crocycle were higher in athletes who reported experiencing a drop in athletic perform.nce during the com.etition season m.crocycle.

关键词： Oxidative Stress 4-Hydroxynonenal Superoxide Dism.tase Athletic perform.nce training m.crocycle

Use of ketam.ne for severe asthm. exacerbation in a pregnant patient with persistent bronchospasm. A case report

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Em.rgency and Critical Care m.dicine 2024年第3期4卷 130-133页

作者： Johnson m. Abbas m. Abdo J. m.nsour m. Jones J. pharm.cy Departm.nt Beaumont Health Dearborn MI United States Em.rgency Center Beaumont Health Dearborn MI United States

Background Estim.ted 4%-8% of pregnancies are com.licated by asthm.. Adequate m.nagem.nt in this population is critical to m.nim.ze com.lications. patients presenting with asthm. exacerbation are typically m.naged with standard bronchodilators and system.c corticosteroids. However, additional agents m.y be used in patients with refractory asthm. exacerbation. Ketam.ne has been used in refractory bronchospasm. although its efficacy in published literature is heterogeneous. Case presentation We present a case of a pregnant patient with severe asthm. exacerbation refractory to standard and salvage treatm.nt who achieved term.nation of bronchospasm.with ketam.ne infusion. Conclusion After receiving ketam.ne infusion for several days, the patient had im.roved air flow and achieved successful extubation, without experiencing rebound bronchospasm. Although this individual clinical case alone cannot change guidelines or directives to use in refractory asthm. exacerbations, it offers a possible treatm.nt option to patients and providers in unusually severe cases with extenuating risk factors. © Wolters Kluwer Health, Inc. All rights reserved.

关键词： Asthm. Bronchospasm. Case Report Ketam.ne pregnancy