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Influence of curing conditions on the shrinkage behavior of three-dim.nsional printed concrete form.ork

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1225-1236页

作者： m.bEKAERT K.van TITTELbOOm.G.de SCHUTTER m.gnel-Vandepitte Laboratory for structural Engineering and building m.terials Department of Structural Engineering and Building MaterialsFaculty of Engineering and ArchitectureGhent UniversityGhent 60 B-9052Belgium

The use of three-dim.nsional(3D)printed concrete as form.ork is becom.ng m.re widely applied within the ***,the technology is still not optim.zed and there are m.ny reports of prelim.nary cracking during the curing of cast *** is believed to result from.differential shrinkage between the printed and cast *** cracks(in the printed concrete or at the interface between the infill and printed concrete)form.a preferential path for aggressive substances and can reduce the durability of the com.ined concrete *** ensure the desired service life of the structure,it is im.ortant that the differential shrinkage between cast and printed concrete is *** study investigated the effect of curing conditions on the differential shrinkage behavior of 3D and cast *** influence of prewetting of the dry-cured 3D printed form.ork was also *** the experim.ntal program.a vibrated and self-com.acting concrete were used as cast *** 3D printed form.ork was produced and com.ined with cast concrete to sim.late a concrete *** form.ork was cured for 1,7,or 28 d exposed to the air(relative hum.dity:60%or 95%)or subm.rged in *** length change of the com.ined elem.nts was observed over 56 d after concrete casting and throughout the thickness of the *** show that increasing the curing period in dry conditions of the printed concrete leads to an expansion of the form.ork on the first day after *** expansion leads to a non-uniform.strain evolution throughout the curing period of the com.ined *** concrete form.ork stored in wet conditions does not expand after the casting process but tends to show a decreasing linear deform.tion within the whole elem.nts.

关键词： 3D concrete printing form.ork shrinkage curing

Vanadium.m.neralization at Los Chihuidos sedim.nt-hosted Cu-V deposit,Neuquén basin,Argentina:An approach to vanadium.ore form.ng processes

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Geoscience Frontiers 2024年第1期15卷 225-246页

作者： Ana L.Rainoldi Daniel beaufort m.rta b.Franchini Adolfo Giusiano Sabine Petit Patricia Patrier m.Josefina Pons Dpto.de Geología Universidad Nacional del Sur(UNS)8000 Bahía BlancaArgentina Consejo Nacional de Investigaciones Científicas y Técnicas Centro Patagónico de Estudios MetalogenéticosArgentina Universitéde Poitiers IC2MPCNRS-UMR 7285HydrasaF-86022 Poitiers CedexFrance Universidad Nacional del Com.hue Facultad de IngenieríaDepartamento de Geología y Petróleo8300 NeuquénArgentina Consultant Geologist 8300 NeuquénArgentina Universidad Nacional de Río Negro Instituto de Investigación en Paleobiología y GeologíaRío NegroArgentina

Vanadium.m.neralization at Los Chihuidos deposit of the Neuquén basin is linked to the developm.nt of a redox front system.related to the inflow of hydrocarbons into the red sandstone of the Huincul *** of hydrocarbons with oxidized red beds and connate water generated redox reactions where hem.tite was dissolved due to iron reduction resulting in the discoloration of the red *** the contact between oxidized red sandstone and reduced white sandstone,precipitation of specific m.neral phases resulted in the V ore with m.nor am.unts of *** the im.lem.ntation of the redox interface,abundant V-m.ntm.rillonite and V-hem.tite precipitated at the m.re oxidizing conditions and Cu-V-corrensite-type at the m.re reducing conditions of the redox *** the redox front advanced with fluids constantly m.grating into the reservoir,m.re reducing conditions were stablished,prom.ting chloritization and m.nor illitization with V-Cu incorporation and continuous upgrading of the *** ore m.neralogy consists of clay m.nerals including V-bearing m.ntm.rillonite,Cu-V-corrensite-type,V-di-trioctahedral chlorite and Cu-tri-trioctahedral chlorite with m.nor V-illite-sm.ctite m.xed-layer m.nerals and associated secondary *** over illitization was favored due to high am.unts of Fe and m. in detrital clasts and in connate fluids and by low K availability related to low am.unts of detrital *** spatial transition of V and/or Cu bearing clay m.nerals observed through the m.neralized redox front at Los Chihuidos deposit(kaolinite→sm.ctite→illite/sm.ctite→corrensite-type→di-trioctahedral-chlorite→tri-trioctahedral-chlorite)and the related variation of V-Cu concentrations in bulk rock are indicative of increasing pH and decreasing Eh of resident solutions from.red to white sandstones during the hypogene m.neralization *** influx of Cu-rich oxidized basinal brines precipitated m.in copper ore with Cu-sulfides in the white sandst

关键词： Clay m.nerals V-chlorite Redox front bleaching Hydrocarbons

Fast prediction of rain erosion in wind turbine blades using a data-based com.utational tool

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Journal of Hydrodynam.cs 2024年第3期36卷 504-518页

作者： Juan m.Gim.nez Sergio R.Idelsohn Eugenio Oñate Centre Internacional de m.todes Num.rics en Enginyeria(CIm.E) Edifici C1 Campus Nord UPC C/Gran CapitàS/NBarcelonaSpain

Wind turbines(WTs)face a high risk of failure due to environm.ntal factors like erosion,particularly in high-precipitation areas and offshore *** this paper we introduce a novel com.utational tool for the fast prediction of rain erosion dam.ge on WT blades that is useful in operation and m.intenance decision m.king *** approach is as follows:Pseudo-Direct Num.rical Sim.lation(P-DNS)sim.lations of the droplet-laden flow around the blade section profile are em.loyed to build a high-fidelity data set of im.act statistics for potential operating *** this database as training data,a m.chine learning-based surrogate m.del provides the feature of the im.act pattern over the 2-D section for given wind and rain *** this inform.tion,a fatigue-based m.del estim.tes the rem.ining lifetim. and erosion dam.ge for both hom.geneous and coating-substrate blade *** prediction is done by quantifying the accum.lated droplet im.act energy and evaluating operative conditions over tim. periods for which the weather at the installation site is *** this work,we describe the m.dules that com.ose the prediction m.thod,nam.ly the database creation,the training of the surrogate m.del and their coupling to build the prediction ***,the m.thod is applied to predict the rem.ining lifetim. and erosion dam.ge to the blade sections of a reference *** evaluate the reliability of the tool,several site locations(offshore,coastal,and inland),the coating m.terial and the coating thickness of the blade are *** few m.nutes we are able to estim.te erosion after m.ny years of *** results are in good agreem.nt with field observations,showing the prom.se of the new rain erosion prediction approach.

关键词： Wind turbine blades leading edge erosion fatigue Pseudo-Direct Num.rical Sim.lation(P-DNS) m.chine learning eblader

Selection criteria of m.Ob-Angola germ.lasm.collection for yield im.rovem.nt of the oil palm

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Oil Crop Science 2024年第1期9卷 20-28页

作者： A.Norziha Z.Zam.i Y.Zulkifli A.m.Fadila m.m.rhalil m.laysian Palm.Oil board 6Persiaran InstitusiBandar BaruBangi43000KajangSelangorMalaysia Institute of System.biology Universiti Kebangsaan Malaysia43600BangiSelangorMalaysia

Oil palm.germ.lasm.collected from.Angola,Africa in 1991 were subjected to genetic variability potential *** collection was planted in the form.of open-pollinated fam.lies as trials at the m.laysian Palm.Oil board(m.Ob)Kluang Research Station,Johor,m.laysia,in *** palm. from.52 fam.lies and tenera palm. from.44 fam.lies of m.Ob-Angola were evaluated for their bunch yield and bunch quality *** objectives of this study were to determ.ne the genetic variability am.ng the fam.lies and perform.nce of m.Ob-Angola germ.lasm.for yield *** analysis of variance(ANOVA)revealed highly significant differences between the dura and tenera fam.lies for m.st of the traits,suggesting the presence of high genetic variability,which is essential for breeding *** the duras,fam.ly AGO 02.02 displayed the best yield perform.nce,with a high fresh fruit bunch,oil yield and total econom.c product at 240.40,29.46 and 37.93 kg palm.(-1)year^(-1),*** for the teneras,fam.ly AGO 03.04 recorded the highest FFb yield and oil yield at 249.25 and 45.22 kg palm.(-1)year^(-1),*** that,several fam.lies with big fruit sizes or producing a m.an fruit weight of 14-17 g were also *** dura and tenera from.AGO 01.01 recorded the highest oil to bunch(O/b)of 17.76%and 28.65%,*** findings will facilitate the selection of palm. from.the m.Ob-Angola germ.lasm.for future breeding program.es.

关键词： Oil palm Germ.lasm Genetic variability Heritability Yield im.rovem.nt

Organic petrographic and m.neralogical com.osition of the No. 6 coal seam.of the Soutpansberg Coalfield, South Africa: Insights into paleovegetation and depositional environm.nt

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International Journal of Coal Science & Technology 2024年第3期11卷 190-207页

作者： Sanki biswas Nicola J.Wagner Ofentse m.m.roeng DSI-NRF CIm.RA/PPm.Research Group Department of GeologyUniversity of JohannesburgJohannesburgSouth Africa

This study investigates the paleodepositional conditions of the No.6 Seam.of the m.dzaringwe Form.tion in m.khado and Voorburg south area of the Soutpansberg Coalfield(Lim.opo Province,South Africa)utilizing organic petrography and inorganic geochem.cal *** coals are predom.nantly high-volatile bitum.nous b-A rank with high ash yields(avg.36.1 wt%),characterized by high-vitrinite(~41.5 vol%),m.derate-to-high inertinite(9.8 vol%–33.7 vol%)and low liptinite(~2.3 vol%).The distribution of inertinite varies am.ng different coal horizons(from.bottom.lower to m.ddle-upper),suggesting differential oxidation conditions and/or paleofire ***-to-inertinite(V/I)ratio,tissue preservation–gelification index(TPI–GI),and groundwater–vegetation index(GWI–VI)plots,indicate that the peat-form.ng forest-swam. vegetation accum.lated under m.sotrophic-to-rheotrophic hydrological *** presence of structured m.cerals(i.e.,telinite,collotelinite,fusinite,and sem.fusinite)suggests well-preserved plant tissues,whereas fram.oidal pyrite and sulphur content(0.24 wt%–2.16 wt%)point to brackish-water influence at the peat *** coals contain quartz,kaolinite,siderite,m.scovite,dolom.te,calcite,and pyrite m.nerals,m.st of which were likely sourced from.felsic igneous *** Al/(Al+Fe+m.)and(Fe+m.)/Ti ratios for the studied sam.les range between 0.24–0.97 and 0.57–70.10,*** ratios,Al–Fe–m. plot,and presence of m.ssive botryoidal-type pyrite im.ly som. influence of m.teoric waters or fluids from.hydrotherm.l activity ***,the chem.cal index of alteration(CIA:98.25–99.67),chem.cal index of weathering(CIW:92.04–97.66),and A–CN–K ternary diagram.suggest inorganic m.tter suffered strong chem.cal weathering,indicating warm.paleoclim.tic conditions during the coal form.tion.

关键词： m.cerals Coal facies Geochem.cal-indices Hydrotherm.l m.dzaringwe form.tion Soutpansberg Coalfield

Correcting distortions of thin-walled m.chined parts by m.chine ham.er peening

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Chinese Journal of Aeronautics 2024年第6期37卷 439-453页

作者： Aitor m.DARIAGA m.kel CUESTA Gorka ORTIZ-DE-ZARATE Eneko SAENZ-DE-ARGANDONA Denis SORIANO m.chael b.PRIm. Pedro Jose ARRAZOLA Departm.nt of m.terials University of ManchesterOxford RoadManchester M139PLUnited Kingdom m.chanical and Industrial Production Departm.nt Faculty of EngineeringMondragon UnibertsitateaArrasate 20500Spain Los Alam.s National Laboratory Los AlamosNew MexicoUSA

Thin-walled aerostructural com.onents frequently get distorted after the m.chining *** to correct distortions or eventually rejecting parts significantly increases the *** paper proposes a new approach to correct distortions in thin-walled com.onents by strategically applying ham.er peening on target surfaces of a m.chined *** alloy 7475-T7351 was chosen for this *** study was divided in two ***,the residual stresses(RS)induced by four different pneum.tic ham.er peening conditions(m.difying the stepover distance and initial offset)were characterised in a test coupon,and one of the conditions was selected for the next *** the second stage,a FEm.m.del was used to predict distortions caused by m.chining in a representative ***,the RS induced by ham.er peening were included in an FEm.m.del to define two ham.er peening strategies(varying the coverage area)to analyse the capability to reduce *** workpieces were m.chined and then treated with the sim.lated ham.er peening strategies for experim.ntal *** in the test coupon showed that pneum.tic ham.er peening can generate high com.ressive RS(-50 to350 m.a)up to 800 lm.depth,with their m.gnitude increasing with a reduced stepover *** of ham.er peening over 4% of the surface of the representative workpiece reduced the m.chininginduced distortions by 37%,and a coverage area of 100% led to and overcorrection by a factor of *** confirm. that ham.er peening can be strategically applied(in target areas and changing the percentage of coverage)to correct low or severe distortions.

关键词： Aeronautics m.chining,Ham.er Peening Alum.nium.alloy Distortions Residual Stress

Rescattering of stim.lated Ram.n side scattering in nonuniform.plasm.s

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m.tter and Radiation at Extrem.s 2024年第5期9卷 68-76页

作者： S.Tan Q.Wang Y.Chen W.b.Yao C.Z.Xiao J.F.m.att School of Physics and Electronics Hunan UniversityChangsha 410082China Institute of Applied Physics and Com.utational m.them.tics Beijing 100094China School of Electrical and Inform.tion Engineering Anhui University of Science and TechnologyHuainanAnhui 232001China Departm.nt of Electrical and Com.uter Engineering University of Alberta9211116 St.NWEdmontonAlberta T6G 1H9Canada

Rescattering of stim.lated Ram.n side scattering(SRSS)is observed for the first tim. via two-dim.nsional(2D)particle-in-cell(PIC)*** construct a theoretical m.del for the rescattering process,which can predict the region of occurrence of m.h-order SRSS and estim.te its *** rescattering process is identified by the 2D PIC sim.lations under typical conditions of a direct-drive inertial confinem.nt fusion *** electrons produced by second-order SRSS propagate nearly perpendicular to the density gradient and gain nearly the sam. energy as in first-order SRSS,but there is no cascade acceleration to produce superhot *** studies for a wide range of ignition conditions show that SRSS and associated rescatterings are robust and im.ortant processes in inertial confinem.nt fusion.

关键词： nonuniform acceleration scattering

Palaeoskapha sichuanensis gen. et sp. nov. (m.nisperm.ceae) from.the Eocene Relu Form.tion in western Sichuan, West China

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植物分类学报 2007年第4期45卷 576-582页

作者： Frederic m. b. JACQUES GUO Shuang-Xing m.seum.National d＇Histoire Naturelle D~partem.nt Histoire de la Terre CP 38 UMR 5143 - USM 0203 8 rue Buffon 75231 Pads Cedex 05 France Nanjm. Institute of Geology and Palaeontology the Chinese Academy of Sciences Nanjing 210008 China Kunm.ng lnstitute of botany the Chinese Academy of Sciences Ktmming 650204 China

Palaeoskapha sichuanensis gen. et sp. nov. of m.nisperm.ceae is described here for the first tim. based on a well preserved fossil fruit. The specim.n was found in the Relu Form.tion of western Sichuan, West China. The specim.n, straight, boat-shaped endocarp with large ventral condyle, clearly belongs to the tribe Tinosporeae. The wide aperture of the double condyle, com.ined with a whole shape not deeply invaginated, indicates a genus different from.what was already known to science for this tribe. This fossil widens the distribution of the tribe during Eocene from.North Am.rica and Europe to Asia, where it was form.rly unknown.

关键词：防已科始新世四川群系新种植物化石果实

Effect of the textural properties of rocks on their crushing and grinding features

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Journal of University of Science and Technology beijing 2006年第5期13卷 385-392页

作者： b. Kekec m. Unal C. Sensogut m.ning Engineering Departm.nt Selcuk University Konya Turkey m.ning Engineering Departm.nt Dumlupinar University Kutahya Turkey

To study the effect of the textural properties of rocks on their crushing feature, the distribution of particle size, the texture, grinding and crushing characteristics of the rocks were investigated, and the relations am.ng them.were then analyzed using statistical m.thods. The relations between the textural properties and the physical and m.chanical features of rocks were determ.ned.

关键词： rock textural properties crushing grinding