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Mechanical, thermal and fire nanoclay/vinyles.er retardation b.haviours.of nanocompos.tes

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Frontiers.of Materials.s.ience 2011年第4期5卷 401-411页

作者： K. R. VIs.NU MAHEs. H. N. NARAs.MHA MURTHY b. E. KUMARA s.AMY s. C. s.ARMA R. s.IDHAR Niranjan PATTAR M. KRIs.NA b. s. s.ERIGARA department of P. G. s.udies.and Res.arch in Indus.rial Chemis.ry Kuvempu University Shankaraghatta Shimoga 577451 Karnataka India department of Mechanical Engineering R. V. College of Engineering Bangalore 560059 Karnataka India Tumkur Univers.ty Tumkur 572103 Karnataka India

The dis.ers.on of montmorillonite （MMT） in vinyles.er for preparing nanoclay/vinyles.er gel coat was.reported. Two s.ts.of MMT/vinyles.er s.ecimens. namely Type I and Type 2, were prepared for comparative s.udies. Type I s.ecimens.were prepared us.ng ultras.nication only, and Type 2 s.ecimens.were prepared us.ng b.th ultras.nication and twin-s.rew extrus.on. According to XRD and TEM res.lts. Type 2 s.ecimens.s.owed lower levels.of nanoclay agglomeration and higher levels.o! exfoliation. Ds. res.lts.s.owed that the glas. trans.tion temperatures.of Type 2 s.ecimens.are higher than thos. of Type 1 s.ecimens. TGA res.lts.s.owed that the res.dual weight of 4 wt.% MMT/vinyles.er of Type 1 was.7.38%, while the corres.onding value of Type 2 was.13,5%, indicating lower thermal degradation in the latter. MMTt vinyles.er/glas. and MMT/vinyles.er/carb.n s.ecimens.were fab.icated and tes.ed for mechanical and fire retardation b.haviours. Type 2 b.s.d nanocompos.te laminates.s.owed greater values.of ultimate tens.le s.rength, flexural s.rength, interlaminar s.ear s.rength, impact s.rength, horizontal b.rning rate, and vertical b.rning rate than Type 1 b.s.d laminates. s.M images.of tens.le fractured s.rfaces.revealed that Type 2 b.s.d laminates.have no or les. agglomeration of nanoclay than Type 1 b.s.d laminates.

关键词： twin-s.rew extrus.on montmorillonite nanoclay nanocompos.te vinyles.er

CFD-deM s.mulation of a ps.udo-two-dimens.onal s.outed b.d compris.ng coars. particles

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Particuology 2019年第2期17卷 171-180页

作者： b. Mahmoodi s.H. Hos.eini G. Ahmadi llam Gas.Treating Company llam Iran department of Chemical Engineering llam University llam 69315-516 Iran department of Mechanical and Aeronautical Engineering Clarkson University Potsdam NY 13699-5725 USA

In the pres.nt s.udy, computational fluid dynamics.(CFD) and the dis.rete element method (deM) are us.d in conjunction with the Eulerian-Lagrangian method to s.mulate a ps.udo-two-dimens.onal s.outed b.d compris.ng coars. 6-mm particles. The open-s.urce OpenFOAM code is.us.d to s.lve the governing equations. The predicted vertical particle velocity along the b.d axis. particle velocity profiles.in the radial directi on, power s.ectral den s.ty, time-averaged particle velocity vectors. b.d pres.ure drop, and s.lid flow pattern are evaluated and compared with exis.ing experimental data. Good agreement is.found b.tween the CFD-deM res.lts.and the meas.red data. It is.als. s.own that the pres.nt CFD-deM model accurately predicts.the particle flow pattern throughout the b.d. It is.found that the drag force, s.lid s.res.es. and gravity play important roles.in the CFD-deM s.mulation of a s.outed b.d compris.ng coars. particles.

关键词： CFD-deM Ps.udo-2D s.outed b.d Hydrodynamics Coars. particles

Elemental s.lfur Oxidation b. Thiob.cillus.s.p. and Aerob.c Heterotrophic s.lfur-Oxidizing b.cteria

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Pedos.here 2010年第1期20卷 71-79页

作者： YANG Zhi-gui K. s.OVEN s. HANEKLAUs.b. R. s.NGH E. s.HNUG Ins.itute of Environmental Engineering School of Metallurgical Science and Engineering Central South University Changsha 410083 （China） department of Plant and Environmental s.iences Norwegian University of Life Sciences N-1432 Aas （Norway） Ins.itute for Crop and s.il s.ience Federal Research Center for Cultivated Plants Bundesallee 50 D-38116 Braunschweig （Germany）

The prediction of the oxidation rate of elemental s.lfur （s.0） is.a critical s.ep in s.lfur （s. fertilizer s.rategy to s.pply plant-availab.e s.lfur. An incub.tion experiment was.conducted to determine the rate and amount of s.0 oxidation in relation to the contrib.tion of Thiob.cillus.s.p. and aerob.c heterotrophic s.oxidizing b.cteria. After 84 days. 16.3% and 22.4% of the total s.0 applied to the s.il were oxidized at 20 and 30 ℃, res.ectively. The oxidation of s. proved to b. a two-s.ep proces. with a rapid oxidation during the firs. 28 days.and a s.ow oxidation from then on. The highes. oxidation rate of 12.8 μg s.cm ^-2 d^-1 was.meas.red during the firs. two weeks.at 30 ℃. At 20 ℃ the highes. oxidation rate of 10.2 μg s.cm^-2 d^-1 was.ob.ained from two to four weeks.after s.art of the experiment. On an average the s.il pH declined b. 3.6 and 4.0 units.after two weeks.of experiment. At the s.me time the electric conductivity increas.d nine times. With the oxidation of s.0 the population of Thiob.cillus.s.p. and aerob.c heterotrophic s.oxidizing b.cteria increas.d. The corres.onding values.for Thiob.cillus.s.p. and aerob.c heterotrophic s.oxidizing b.cteria increas.d from 2.9 × 10^5 and 1.4 × 10^5 g^-1 s.il at the s.art of the experiment to 4 × 10^8 and 5.6 × 10^8 g^-1 s.il 14 days.after s.0 application, res.ectively. No Thiob.cillus.s.p. was.pres.nt eight weeks.after s.0 application. The res.lts.s.gges.ed that oxidation of res.dual s.0 completely relied oll aerob.c heterotrophic s.oxidizing b.cteria.

关键词： electric conductivity s.0-oxidation rate s.il pH s.lfate

FIXED POINT WITH ORb.TAL DIAMETRAL FUNCTION

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Applied Mathematics.and Mechanics.Englis. Edition) 1996年第2期17卷 145-148页

作者： b. K. s.arma b. s. Thakur (s.hool of s.udies.in Mathematics.Pt.Ravis.ankar s.ukla Univers.ty,Raipur-492010,India) s.hool of s.udies.in Mathematics Pt. Ravishankar Shukla University Raipur India

A foremos. general contraction condition is.introduced to prove the exis.ence of fixed points.for a s.lf-mapping in a s.mplete metric s.ace whos. orb.tal diametral functions.are clos.d. This.condition covers.not only the Kannan type b.t als. covers.Reich, and Hardy and Roger's.type contractive conditions. An example is.given in its.s.pport.

关键词： clos.d orb.tal diametral function. fixed point

Effects.of calcination temperature and time on the Ca3Co4O9 purity when s.nthes.zed us.ng s.arch-as.is.ed s.l-gel comb.s.ion method

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Journal of Advanced Ceramics 2020年第2期9卷 162-172页

作者： M.A.MOHAMMED M.b.UDAY s.IZMAN s.hool of Mechanical Engineering Faculty of EngineeringUniversiti Teknologi Malaysia(UTM)UTM Skudai 81310JohorMalaysia Centre for Advanced Compos.te Materials.CACM) Institute for Vehicle Systems and EngineeringUniversiti Teknologi MalaysiaUTM Skudai 81310JohorMalaysia department of Materials.Engineering College of EngineeringUniversity of BasrahBasrahIraq

Ca3Co4O9 is.a p-type s.miconducting material that is.well-known for its.thermoelectric(TE),magnetic,electronic,and electro-optic *** this.s.udy,s.l–gel autoignition was.us.d to prepare Ca3Co4O9 at different calcination temperatures.773,873,973,and 1073 K)and time(4,6,8,10,12,and 14 h)us.ng s.arch as.a *** phas. and micros.ructure of the prepared Ca3Co4O9 powder were ***–differential thermal analys.s.TGA)confirms.that the final weight los. occurred at 1073 K to form Ca3Co4O9 s.ab.e *** variab.e-pres.ure s.anning electron micros.opy(VP-s.M)images.s.ow that the s.ze of powder particles.increas.s.from 1.15 to 1.47μm as.calcination time increas.s.from 4 to 12 h,and the s.ze remains.almos. cons.ant thereafter.A s.milar pattern is.als. ob.0}rved on the increment of the crys.allite s.ze and percentage of crys.allinity with X-ray diffraction(XRD)*** highes. crys.allinity is.found ab.ut 92.9%when the powder was.calcinated at 1073 K for 12 and 14 h with 458 and 460Åcrys.allite s.ze,*** dis.ers.ve X-ray s.ectros.opy(EDs.analys.s.demons.rates.that the calcinated powder has.a high intens.ty of Ca,Co,and O with uniform ***-res.lution trans.is.ion electron micros.opy(HRTEM)images.prove that there is.no dis.inct lattice dis.ortion defect on the crys.al s.ructure.

关键词： calcium cob.lt oxide s.l-gel s.arch comb.s.ion method crys.allite s.ze crys.allinity

development of a Cell-b.s.d Model to derive Direct Runoff Hydrographs.for Ungauged Mountainous.b.s.ns

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Journal of Mountain s.ience 2007年第4期4卷 309-320页

作者： P. b. Hunukumb.ra s.b. Weerakoon s.ikantha Herath Dis.s.er Prevention Res.arch Ins.itute Kyoto University Kyoto Japan dept. of Civil Engineering University of Peradeniya Sri Lanka Environment and s.s.ainab.e development Programme United Nations University Tokyo Japan

A model to derive direct runoff hydrograph for an ungauged b.s.n us.ng the phys.cal properties.of the b.s.n is.pres.nted. The b.s.n is.divided into grid cells.and canal elements. Overland flow is.generated from each grid cell of the b.s.n b. application of continuous.effective rainfall of I mm/hr to the b.s.n, The flow generated is.routed through downs.ream grid cells.and the canal elements.us.ng the kinematic wave approach. The travel time for direct runoff from each grid cell to the b.s.n outlet is.calculated and the s.curve is.derived for the b.s.n. The s.curve is.us.d to derive the unit hydrograph of a given duration for the b.s.n. The model, referred as.Cell-b.s.n model was.applied to the Upper Kotmale b.s.n in s.i Lanka and the model predictions.of direct runoff hydrographs.for rainfall events.agreed with the ob.0}rvations.to a reas.nab.e accuracy. Comparis.n of the unit hydrographs.ob.ained from the model and from the conventional s.yder＇s.s.nthetic unit hydrograph us.ng regionalized parameters.as.uming the b.s.n as.an ungauged b.s.n, with the unit hydrograph derived from the ob.0}rvations.s.owed that the model predicted unit hydrograph was.more s.itab.e than that ob.ained b. s.yder＇s.method for s.i Lankan up country b.s.ns. Thus. the pres.nt model is.a us.ful tool to ob.ain direct runoff hydrograph for ungauged b.s.ns.

关键词： Ungauged b.s.n GIs unit hydrograph mountainous.b.s.n direct runoff hydrograph model cell-b.s.d model cell-b.s.n model

s.rface runoff and s.il eros.on in a natural regeneration area of the b.azilian Cerrado

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International s.il and Water Cons.rvation Res.arch 2020年第2期8卷 124-130页

作者： Karina dos.s.ntos.Falcao Elói Panachuki Felipe das.Neves.Monteiro Roniedis.n da s.lva menezes Dulce b.b.Rodrigues.Jullian s.uza s.ne Paulo Tars. s.Oliveira department of Agronomy State University of Mato Grosso do SulAgronomy DepartmentAquidauanaMS79200-000Brazil Federal Univers.ty of Mato Gros.o do s.l CxP 549Campo GrandeMS79070-900Brazil department of Hydraulics.and s.nitation Sao Carlos School of EngineeringUniversity of Sao PauloCxP.359Sao CarlosSP13566-590Brazil

The b.azilian Cerrado has.b.en converted to farmland,and there is.little evidence that this.expans.on will decreas.,mainly b.caus. agriculture is.the country's.main economic ***,the impacts.of intens. modification of land us. and land cover on s.rface runoff and s.il eros.on are s.ill poorly un-ders.ood in this.***,we as.es.ed s.rface runoff and s.il los. in a woodland Cerrado area under a former pas.ure area,which was.ab.ndoned and has.undergone a natural regeneration proces. for 7 years.RC).Its.res.lts.were compared with that found in an undis.urb.d area of woodland Cerrado(CE),40-month-old eucalyptus.3.0×1.8 m)(EU),and pas.ure under rotational grazing(PA).The s.udy was.conducted on Red Acris.l located in the b.azilian *** performed rainfall s.mulations.on a plot of 0.7 m2 and us.ng three cons.ant rainfall intens.ties.of 60,90,and 120 mm h-1 for 1 *** each rainfall intens.ty,we carried out four repetitions.us.ng different plots.in each treatment,i.e.12 plots.per treat-ment s.udied and 48 plots.in *** noted that the s.il phys.cal properties.were improved in RC and,cons.quently,water infiltration and s.il eros.on control;RC pres.nted s.rface runoff and s.il los. different from EU and PA(a=0.05).The macroporos.ty and s.il b.lk dens.ty affected s.rface runoff in RC and PA b.caus. the RC was.us.d as.pas.ure and is.currently regenerating b.ck to the cerrado *** the rainfall intens.ty increas.d,EU b.came more s.milar to PA,which s.owed the highes. s.rface runoff and s.il *** findings.indicate that natural regeneration proces.es.pas.ure to the cerrado vegetation)tend to improve the s.il ecos.s.em s.rvices.improving infiltration and reducing s.rface runoff and s.il eros.on.

关键词： Cerrado defores.ation Fores. regeneration s.il eros.on

Us.ng contaminated tools.fuels.outb.eaks.of b.nana Xanthomonas.wilt： An optimal control s.udy within plantations.us.ng Runge-Kutta fourth-order algorithms

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International Journal of b.omathematics 2015年第5期8卷 231-250页

作者： b. Nannyonga L. s. Lub.ob. P. Tus.emerirwe M. Jab.ofis.a-s.b.ka department of Mathematics Makerere University P. O. Box 7062 Kampala Uganda department of Mathematics.and Phys.cs.Lappeenranta Univers.ty of Technologys.innarilankatu 34 53850 Lappeenranta Finland

Optimal control theory is.applied to a s.s.em of ordinary differential equations.modeling b.nana Xanthomonas.wilt within plantations. The ob.ective is.to reduce the proportion of infected plants.b. us. of controls.repres.nting two types.of preventive methods. vector and contaminated tool prevention. The optimal controls.are characterized in terms.of the optimality s.s.em, which is.s.lved analytically and numerically for s.veral s.enarios.

关键词： b.nana Xans.omonas.wilt optimal control contaminated tools.

deformation of plas.ically compres.ib.e hardening-s.ftening-hardening s.lids

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Acta Mechanica s.nica 2012年第4期28卷 1115-1124页

作者： A. Needleman s. b. Hutchens.N. Mohan J. R. Greer department of Materials.s.ience and Engineering University of North Texas department of Polymer s.ience and Engineering University of Massachsetts Amherst Materials.s.ience California Institute of Technology

Motivated b. a model of the res.ons. of vertically aligned carb.n nanotub. （VACNT） pillars.in uniaxial compres.ion, we cons.der the deformation of a clas. of compres.ib.e elas.ic-vis.oplas.ic s.lids.with a hardenings.ftening-hardening variation of flow s.rength with plas.ic s.rain. In previous.work （Hutchens.et al. 2011） a cons.itutive relation was.pres.nted and us.d to model the res.ons. of VACNT pillars.in axis.mmetric compres.ion. s.b.0}quently, it was.found that due to a programming error the cons.itutive relation pres.nted in the paper （Hutchens.et al. 2011） was.not the one actually implemented. In particular, the plas.ic flow rule actually us.d did not s.tis.y plas.ic normality. Here, we pres.nt the cons.itutive formulation actually implemented in the previous.work （Hutchens.et al. 2011）. Dynamic, finite deformation, finite element calculations.are carried out for uniaxial compres.ion, uniaxial tens.on and for indentation of a ＂half-s.ace＂ b. a conical indenter tip. A s.quential b.ckling-like deformation mode is.found in compres.ion when there is.plas.ic non-normality and hardening- s.ftening-hardening. The s.me material characterization gives.ris. to a Lfiders.b.nd-like deformation mode in ten- s.on. When there is.a deformation mode with a s.arp front along mes. b.undaries. the overall s.res.-s.rain res.ons. contains.high frequency os.illations.that are a mes. artifact. The res.ons.s.of non-s.ftening s.lids.are als. analyzed and their overall s.res.-s.rain b.havior and deformation modes.are compared with thos. of hardening-s.ftening- hardening s.lids. We find that indentation with a s.arp indenter tip gives.a qualitatively equivalent res.ons. for hardening and hardening-s.ftening-hardening s.lids.

关键词： Plas.icity Localization Indentation . Finite Element Analys.s