检索结果-南通市图书馆

Pavement sustainability index fo. highway infrastructures： A case study o. Maryland

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fro.tiers o. Structural and Civil Engineering 2018年第2期12卷 192-200页

作者： Stella o. o.AZEE-IGBINEDIo. o.udare owolabi Mo.tgo.ery Co.nty Department of Transportation 100 Edison Park Drive Gaithersburg MD 20878 USA Department o. Civil Engineering Morgan State University 1700 East Cold Spring Lane Baltimore MD 21251 USA

Pavement deterio.atio. creates co.ditio.s that undermine their perfo.mances, which gives rise to.the need fo. maintenance and rehabilitatio.. This paper develo.s a mathematical multi-linear regressio. analysis （MLRA） mo.el to.determine a pavement sustainability index （PSTI） as dependent variable fo. flexible pavements in Maryland. Fo.r catego.ies o. pavement perfo.mance evaluatio. indicato.s are subdivided into.seven pavement co.ditio. indices and analyzed as independent variables fo. each sectio. o. pavement. Data are co.lected fro. five different ro.dways using field evaluatio.s and existing database. Results indicate that co.fficient o. determinatio. （R^2） is co.related and significant, R^2 = 0.959. o. the seven independent variables, present serviceability index （PSI） is the mo.t significant with a co.fficient value o. 0.032, present serviceability rating （PSR） co.fficient value=0.028, and internatio.al ro.ghness index （IRI） co.fficient value = -0.001. Increasing each unit value o. co.fficients fo. PSI and PSR wo.ld increase the value o. PSTI; thereby pro.iding a mo.e sustainable pavement infrastructure; which explains the significance o. the mo.el and why IR/ will mo.t likely impact enviro.mental, eco.o.ic and so.ial values.

关键词： pavement indices sustainability pavement perfo.mance flexible pavements

Mo.eling and Simulatio. o. Micro.tructurally Small Crack Fo.matio. and Gro.th in No.ched Nickel-base Superallo. Co.po.ent

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Jo.rnal o. Materials Science & Techno.o.y 2014年第3期30卷 203-212页

作者： G.M.owolabi H.A.Whitwo.th Department o. Mechanical Engineering Howard University

Studies o. micro.tructurally small fatigue cracks have illustrated that hetero.eneo.s micro.tructural features such as inclusio.s, po.es, grain size distributio. as well as precipitate size distributio. and vo.ume fractio. create sto.hasticity in their behavio. under cyclic lo.ds. Therefo.e, to.enhance safe-life and damage-to.erance appro.ches, accurate mo.eling o. the influence o. these hetero.eneo.s micro.tructural features o. micro.tructurally small crack fo.matio. and gro.th fro. stress raisers is necessary. In this wo.k, co.putatio.al micro.echanics was used to.predict the high cycle fatigue o. micro.tructurally small crack fo.matio. and gro.th in no.ched po.ycrystalline nickel-base superallo.s and to.quantify the variability in the driving fo.ce fo. fo.matio. and gro.th o. micro.tructurally small crack fro. no.ch ro.t in the matrix with no.-metallic inclusio.s. The framewo.k invo.ves co.putatio.al mo.eling to.o.tain three-dimensio.al perspectives o. micro.tructural features influencing fatigue crack gro.th in no.ched nickel-base superallo.s, which acco.nts fo. the effects o. no.lo.al no.ch ro.t plasticity, lo.ding, micro.tructural variability, and extrinsic defects o. lo.al cyclic plasticity at the micro.tructure-scale level. This appro.ch can be used to.explo.e sensitivity o. minimum fatigue lifetime to.micro.tructures. The simulatio. results o.tained fro. this framewo.k were calibrated to.existing experimental results fo. po.ycrystalline nickel-base superallo.s.

关键词： Micro.tructuraliy small crack Crystal plasticity Nickel-base superallo. Fatigue life

Shear Band Fo.matio. in AISI 4340 Steel Under Dynamic Impact Lo.ds:Mo.eling and Experiment

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2013年第4期26卷 378-384页

作者： Daniel o.o. Gbadebo.owolabi Akindele o.eshi Ho.ace Whitwo.th Department o. Mechanical Engineering Howard University Department o. Mechanical Engineering University of Saskatchewan57 Campus DriveSaskatoonSKS7N 5A9Canada

In this study, the o.currence o. the adiabatic shear bands in AISI 4340 steel under high velo.ity impact lo.ding was investigated using finite element analysis and experimental tests. The cylindrical specimen subjected to.the impact lo.d was divided into.different regio.s separated by no.es using finite element metho. in ABAQUS enviro.ment with bo.ndary co.ditio.s specified. The material pro.erties were assumed to.be lo.er in the regio. where the pro.ability o. strain lo.alizatio. is high based o. prio. experimental results in o.der to.initialize the fo.matio. o. the adiabatic shear bands. The finite element mo.el was used to.determine the maximum flo. stress, the strain hardening, the thermal so.tening, and the time to.reach the critical strain fo. the fo.matio. o. adiabatic shear bands. Experimental results sho. that defo.med bands were fo.med at lo. strain rates and there was a minimum strain rate required fo. the fo.matio. o. the transfo.med band in the allo. and the cracks were initiated and pro.agated alo.g the transfo.med bands leading to.fragmentatio. under the impact lo.ding. The susceptibility o. the adiabatic shear bands to.cracking was markedly influenced by the strain-rates and the initial material micro.tructure. The simulatio. results o.tained were co.pared with the experimental results o.tained fro. the AISI 4340 steel under high strain-rate lo.ding in co.pressio. using split impact Ho.kinso. bars. A go.d agreement between the experimental and simulatio. results was o.tained.

关键词： Adiabatic shear bands Finite element mo.el Strain hardening Thermal so.tening Jo.nso.-Co.k mo.el AISI 4340 steel

Reservo.r Evaluatio. and Vo.umetric Analysis o. Rancho.Field, Niger Delta, Using Well Lo. and 3D Seismic Data

在线全文

学校读者我要写书评

暂无评论

o.en Jo.rnal o. Geo.o.y 2019年第13期9卷 974-987页

作者： A. o. owolabi B. o. o.ang o. P. o.etade o. B. Akindele Department o. Mining Engineering Federal University of Technology Akure Nigeria Department o. Geo.o.y University of Calabar Calabar Nigeria

Explo.atio. and explo.tatio. fo. hydro.arbo. are asso.iated with a lo. o. co.plexities, it is therefo.e necessary to.integrate available geo.o.ic mo.els fo. accurate hydro.arbo. pro.pecting and risk analysis. This study is aimed at determining the structural, petro.hysical and vo.umetric parameters fo. reservo.r evaluatio. within the Rancho.field. 3D seismic data was used fo. evaluating the hydro.arbo. po.ential o. the field. A suite o. well lo.s but no. limited to.gamma ray lo.s (GR), deep resistivity lo. (DRES), neutro. lo. (NPHI) and density lo. (RHo.) fro. fo.r (4) wells were emplo.ed in characterising dynamic pro.erties o. the reservo.rs. The GR lo. was used in litho.o.y identificatio. while the resistivity lo. was used in identifying pro.able hydro.arbo. bearing sands. A co.relatio. exercise was carried o.t to.identify lateral co.tinuity and disco.tinuity o. facies acro.s the wells. Thereafter petro.hysical parameters were analysed fro. the suite o. wire line lo.s. Majo. faults were mapped o. the 3D seismic data and identified hydro.arbo. bearing sand to.s fro. the well lo.s were mapped as ho.izo.s o. the seismic sectio., maps were generated and vo.umetric analysis was do.e. Nine (9) hydro.arbo. sands (Sands A - I) were identified within the study area. The well lo. revealed an alternatio. o. sand and shale layers as well as shale layers increased in thickness with depth, while the sand bo.ies reduced in thickness with depth which characterized the Abgada Fo.matio. o. the Niger Delta. The effective po.o.ities o. the sands range fro. 21% - 31%, the permeability ranges fro. 28% - 44%, 70% - 80% fo. the net to.gro.s, vo.ume o. shale range fro. 14% - 40% and hydro.arbo. saturatio. ranges fro. 63% - 82%. Twelve (12) faults were mapped within the study area and the structural styles revealed a fault assisted clo.ures. The vo.umetric analysis sho.ed that Sand F had Sto.k Tank o.l Initially In Place (STo.IP) o. 5,050,000,000 bbls o. o.l and Sand G had STo.IP o. 17,870

关键词： Neutro. Lo. Density Lo. Sto.k Tank o.l Initially In Place Gro.s Ro.k Vo.ume

Analysis o. Mathematics and Numerical Pattern Fo.matio. in Superdiffusive Fractio.al Multico.po.ent System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2017年第6期9卷 1438-1460页

作者： Ko.ade M.owolabi Abdo. Atangana Institute fo. Gro.ndwater Studies Faculty of Natural and Agricultural SciencesUniversity of the Free StateBloemfontein 9300South Africa

In this wo.k,we examine the mathematical analysis and numerical simulatio. o. pattern fo.matio. in a subdiffusive multico.po.ents fractio.al-reactio.diffusio. system that mo.els the spatial interrelatio.ship between two.preys and predato. *** majo. result is centered o. the analysis o. the system fo. linear *** o. the main mo.el reflects that the dynamical system is lo.ally and glo.ally asympto.ically *** pro.o.e so.e useful theo.ems based o. the existence and permanence o. the species to.validate o.r theo.etical *** and efficient metho.s in space and time are fo.mulated to.handle any space fractio.al reactio.-diffusio. *** numerically present the co.plexity o. the dynamics that are theo.etically *** simulatio. results in o.e,two.and three dimensio.s sho. so.e amazing scenario..

关键词： Asympto.ically stable co.xistence Fo.rier spectral metho. numerical simulatio.s predato.-prey fractio.al multi-species system

Analysis and Dynamics o. Illicit Drug Use Described by Fractio.al Derivative with Mittag-Leffler Kernel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Co.puters, Materials & Co.tinua 2020年第12期65卷 1905-1924页

作者： Berat Karaagac Ko.ade Matthew owolabi Ko.takkaran So.ppy Nisar Faculty o. Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh CityVietnam Department o. Mathematics Educatio. Faculty of EducationAdıyaman UniversityAdıyamanTurkey Department o. Mathematical Sciences Federal University of TechnologyAkureNigeria Department o. Mathematics College of Arts and SciencesWadi AldawaserPrince Sattam Bin Abdulaziz UniversityAl KharjSaudi Arabia

Illicit drug use is a significant pro.lem that causes great material and mo.al lo.ses and threatens the future o. the *** this reaso.,illicit drug use and related crimes are the mo.t significant criminal cases examined by *** paper aims at mo.eling the illegal drug use using the Atangana-Baleanu fractio.al derivative with Mittag-Leffler ***,in this wo.k,the existence and uniqueness o. so.utio.s o. the fractio.al-o.der Illicit drug use mo.el are discussed via Picard-Lindelöf theo.em which pro.ides successive appro.imatio.s using a co.vergent *** the stability analysis fo. bo.h disease-free and endemic equilibrium states is co.ducted.A numerical scheme based o. the kno.n Adams-Bashfo.th metho. is designed in fractio.al fo.m to.appro.imate the no.el Atangana-Baleanu fractio.al o.erato. o. o.der 0o. results based o. different values o. fractio.al o.der,which also.serve as co.tro. parameter,are presented to.justify the theo.etical findings.

关键词： Atangana-Baleanu fractio.al o.erato. illicit drug use existence and uniqueness o. so.utio.s stability analysis

Effects o. regenerative mechanical vibratio. o. the mechanical integrity o. ceramic diesel particulate filters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Jo.rnal o. Advanced Ceramics 2018年第1期7卷 5-16页

作者： Gbadebo.owolabi Akindele o.ESHI Paul RAGALLER AlexANDer SAPPo. Department o. Mechanical Engineering Howard University Department o. Mechanical Engineering University of Saskatchewan CTS Co.po.atio. Bo.to. Inno.atio. o.fice

In this study, the effects o. mechanical vibratio. o. the mechanical pro.erties o. ceramic diesel particulate filters(DPFs) were investigated. The go.l is to.determine ho. the mechanical vibratio. used in the regenerative ash cleaning pro.ess fo. these filters affects their mechanical integrity during subsequent reuse. Bo.h virgin and vibrated DPF samples were subjected to.co.pressive and 3-po.nt flexural lo.ding at three different lo.ding rates alo.g axial and tangential directio.s. Statistical analysis was co.ducted to.determine the significance o. variatio. in the co.pressive and flexural strengths o. the DPFs as a result o. expo.ure to.mechanical vibratio.. The results sho. that there is no.statistically significant difference in bo.h co.pressive and flexural strengths o. the virgin DPFs and the DPFs subjected to.the same level o. mechanical vibratio. typically used in ash cleaning o. DPFs. When the intensity o. vibratio. was do.bled, the dro. in co.pressive strength became statistically significant, but less than 10% under axial lo.ding. Ho.ever, no.dro. in flexural strength was o.served fo. DPFs subjected to.this high intensity o. mechanical vibratio.. The safe thresho.d fo. mechanical vibratio. o. ceramic filters is co.sidered to.be much higher than that currently used in vibratio.-based ash cleaning pro.ess.

关键词： diesel particulate filter(DPF) co.dierite mechanical testing filter regeneratio. vibratio. based ash cleaning techno.o.y

Co.pariso. o. Functio.al Pro.erties between Native and Chemically Mo.ified Starches fro. Acha (<i>Digitaria</i>Stapf) Grains

在线全文

学校读者我要写书评

暂无评论

Fo.d and Nutritio. Sciences 2014年第2期5卷 222-230页

作者： B. I. o.u-owolabi o. o. o.ayinka A. A. Adegbemile K. o. Adebo.ale Department o. Chemistry University of Ibadan Ibadan Nigeria Department o. Enviro.mental Management and To.ico.o.y College of Environmental Resources and Management Federal University of Agriculture Abeokuta Nigeria.

Acha grain (Digitariaexilis) starch was iso.ated and subjected to.chemical mo.ificatio.s by acetylatio., benzylatio., succinylatio., carbo.ymethylatio. and acid-thining. Functio.al pro.erties (swelling, so.ubility, gelatio., o.l and water abso.ptio. capacities, alkaline water retentio.) and rheo.o.ical pro.erties o. the native and mo.ified starches were determined. Swelling po.er and so.ubility o. the starch samples increased with increase in temperature. Swelling po.er and so.ubility were pH dependent, with maximum values o.tained at pH 12 in bo.h native and mo.ified starches. Increasing degree o. alkalinity increased bo.h so.ubility and swelling capacity. Water abso.ptio. capacities o. chemically mo.ified starches decreased, but acetylated starch, ATAS sho.ed higher value co.pared to.the native and also.chemically mo.ified starches impro.ed o.l abso.ptio. capacity o. the native starch. The mo.ified starches sho.ed increase in alkaline water retentio.. Gelatio. studies revealed that ACAS had higher LGC than the native while so.e chemically mo.ified starches did no. alter the gelatio. capacity o. the native starch except fo. BAS and ACAS with LGC o. 10% and 16% v/w. There were significant differences in functio.al pro.erties between native and chemically mo.ified starches fro. acha, so.chemical mo.ificatio. impro.ed functio.al pro.erties. Chemical mo.ificatio.s increased pasting temperature except fo. ATAS and BAS. Set-back values were reduced after mo.ificatio.s, indicating that mo.ificatio. wo.ld minimize starch retro.radatio..

关键词： (Digitariaexilis Stafp) Functio.al Pro.erties Chemical Mo.ificatio. Rheo.o.ical Pro.erties Starches

Develo.ment o. a particle swarm o.timizatio. based suppo.t vecto. regressio. mo.el fo. titanium dio.ide band gap characterizatio.

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Jo.rnal o. Semico.ducto.s 2019年第2期40卷 49-55页

作者： Tao.eed o.owolabi Physics and Electro.ics Department Adekunle Ajasin University Co.puter Info.matio. System Department College of Computer Science and Information Technology Imam Abdulrahman bin Faisal University Physics Department King Fahd University of Petroleum and Minerals

Energy band gap o. titanium dio.ide(Tio.2) semico.ducto. plays significant ro.es in many practical applicatio.s o. the semico.ducto. and determines its appro.riateness in techno.o.ical and industrial applicatio.s such as UV abso.ptio., pigment,pho.o.catalysis, po.lutio. co.tro. systems and so.ar cells amo.g o.hers. Substitutio. o. impurities into.crystal lattice structure is the mo.t co.mo.ly used metho. o. tuning the band gap o. Tio.2 fo. specific applicatio. and eventually leads to.lattice disto.tio.. This wo.k utilizes the disto.tio. in the lattice structure to.estimate the band gap o. do.ed Tio.2, fo. the first time, thro.gh hybridizatio. o. a particle swarm o.timizatio. algo.ithm(PSo. with a suppo.t vecto. regressio.(SVR) algo.ithm fo. develo.ing a PSo.SVR mo.el. The precisio. and accuracy o. the develo.ed PSo.SVR mo.el was further justified by applying the mo.el fo. estimating the effect o. co.alt-sulfur co.do.ing, nickel-io.ine co.do.ing, tungsten and indium do.ing o. the band gap o. Tio.2 and excellent agreement with the experimentally repo.ted values was achieved. Practical implementatio. o. the pro.o.ed PSo.SVR mo.el wo.ld further widen the applicatio.s o. the semico.ducto. and reduce the experimental stress invo.ved in band gap determinatio. o. Tio.2.

关键词： band gap lattice disto.tio. crystal lattice parameters particle swarm o.timizatio. suppo.t vecto. regressio. titanium dio.ide