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Comparative impact behaviours of ultra high performance concrete columns reinforced with polypropylene vs steel fibres

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Defence Technology（防务技术） 2024年第10期40卷 138-153页

作者： Thong m.Pham harrison Hyde maw K.Kaung Yan Zhuge Duong T.Tran Des Vlietstra Tung m.Tran uniSA STEMUniversity of South AustraliaMawson LakesSA 5095Australia BG&E Pty Ltd Wellington StreetPerthWA6000Australia Austral Construction Pty Ltd St Georges TerracePerthWA6000Australia Centre for Infrastructural monitoring and Protection(CImP) Curtin UniversityKent StBentleyWA 6102Australia barchip Australia Pty Ltd U 26 Qualtroughq StreetWoolloongabbaQueensland4102Australia Sustainable Developments in Civil Engineering Research Group Faculty of Civil EngineeringTon Duc Thang UniversityHo Chi Minh City72915Viet Nam

Polypropylene(PP)fibres have primarily used to control shrinkage cracks or mitigate explosive spalling in concrete structures exposed to fire or subjected to impact/blast loads,with limited investigations on capacity *** study unveils the possibility of using PP micro-fibres to improve the impact behaviour of fibre-reinforced ultra-high-performance concrete(FRuHPC)*** show that the addition of fibres significantly improves the impact behaviour of FRuHPC columns by shifting the failure mechanism from brittle shear to favourable flexural *** addition of steel or PP fibres affected the impact responses *** fibres considerably increased the peak impact force(up to 18%)while PP micro-fibres slightly increased the peak(3%-4%).FRuHPC significantly reduced the maximum midheight displacement by up to 30%(under 20impact)and substantially improved the displacement recovery by up to 100%(under 20impact).FRuHPC with steel fibres significantly improved the energy absorption while those with PP micro-fibres reduced the energy absorption,which is different from the effect of PP-macro fibre reported in the *** optimal fibre content for micro-PP fibres is 1%due to its minimal fibre usage and low peak and residual *** study highlights the potential of FRuHPC as a promising material for impact-resistant structures by creating a more favourable flexural failure mechanism,enhancing ductility and toughness under impact loading,and advancing the understanding of the role of fibres in structural performance.

关键词： ultra high-performance concrete Steel fibre Polypropylene micro-fibre Fibre volume fraction Impact loading Pendulum tests Columns

Applying machine Learning Approach to Explore Childhood Circumstances and Self-Rated Health in Old Age-China and the uS,2020-2021

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China CDC weekly 2024年第11期6卷 213-218,I0008-I0013页

作者： Shutong Huo Derek Feng Thomas m.Gill Xi Chen Department of Health Society&BehaviorPublic HealthUniversity of CaliforniaIrvineCAUSA Department of Statistics and Data Science Yale UniversityNew HavenCTUS Department of Internal medicine Yale School of MedicineNew HavenCTUS Department of Health Policy and management Yale School of Public HealthNew HavenCTUS Department of Economics Yale UniversityNew HavenCTUS.

Introduction:Childhood circumstances impact senior health,prompting the introduction of machine learning methods to assess their individual and collective contributions to senior ***:using health and retirement study(HRS)and China Health and Retirement Longitudinal Study(ChaRLS),we analyzed 2,434 American and 5,612 Chinese participants aged 60 and *** inference trees and forests were employed to estimate the influence of childhood circumstances on self-rated health(SRH).Results:The conventional method estimated higher inequality of opportunity(IOP)values in both China(0.039,accounting for 22.67%of the total Gini coefficient 0.172)and the uS(0.067,accounting for 35.08%of the total Gini coefficient 0.191).In contrast,the conditional inference tree yielded lower estimates(China:0.022,accounting for 12.79%of 0.172;uS:0.044,accounting for 23.04%of 0.191),as did the forest(China:0.035,accounting for 20.35%of 0.172;uS:0.054,accounting for 28.27%of 0.191).Childhood health,financial status,and regional differences were key determinants of senior *** conditional inference forest consistently outperformed others in predictive accuracy,as demonstrated by lower out-of-sample mean squared error(mSE).Discussion:The findings emphasize the need for early-life interventions to promote health equity in aging *** learning showcases the potential in identifying contributing factors.

关键词： collective inequality estimates

Effect of neutral polymeric bonding agent on tensile mechanical properties and damage evolution of NEPE propellant

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Defence Technology（防务技术） 2024年第2期32卷 357-367页

作者： m.Wubuliaisan Yanqing Wu Xiao Hou Kun Yang Hongzheng Duan Xinmei Yin State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China The Fourth Institute of China Aerospace Science and Technology Corporation Xi'an710025PR China School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081PR China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyHubei441003PR China

Introducing Neutral Polymeric bonding agents(NPba) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could improve the adhesion between filler/matrix interface, thereby contributing to the development of new generations of the NEPE propellant with better mechanical properties. Therefore,understanding the effects of NPba on the deformation and damage evolution of the NEPE propellant is fundamental to material design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different amounts of NPba. The damage evolution in terms of interface debonding is further investigated using a cohesive-zone model(CZm). Experimental results show that the initial modulus and strength of the NEPE propellant increase with the increasing amount of NPba while the elongation decreases. meanwhile, the relaxation rate slows down and a higher long-term equilibrium modulus is reached. Experimental and numerical analyses indicate that interface debonding and crack propagation along filler-matrix interface are the dominant damage mechanism for the samples with a low amount of NPba, while damage localization and crack advancement through the matrix are predominant for the ones with a high amount of NPba. Finally, crosslinking density tests and simulation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

关键词： Solid propellant Bonding agent mechanical properties Damage evolution Cohesive-zone model Interface debonding

高原世居藏族与移居汉族健康青年足底压力分布特征对比

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皮革科学与工程 2024年第1期34卷 93-100页

作者：孙鑫娄本敬谢露边巴三峡大学附属仁和医院湖北宜昌443000 西藏大学医学院西藏拉萨850000 西藏大学高原医学研究中心西藏拉萨850000

探讨高原世居藏族与移居汉族健康青年足底压力分布规律,比较两个民族青年人群足底压力特征差异。为构建高原人群步态数据库提供基础数据。运用意大利mPS足底压力测试系统对经过筛选的西藏大学在校世居与移居高原健康青年160人进行双足... 详细信息

探讨高原世居藏族与移居汉族健康青年足底压力分布规律,比较两个民族青年人群足底压力特征差异。为构建高原人群步态数据库提供基础数据。运用意大利mPS足底压力测试系统对经过筛选的西藏大学在校世居与移居高原健康青年160人进行双足足底压力测试,对获取的数据进行统计学分析。结果表明:(1)站立时男性接触面积、女性峰值压强、平均压强、足弓指数在民族间存在差异(Pm5)区域的接触面积、T1、T2~5、第2跖骨(m2)区域的压力峰值、足中部(mF)区域的峰值压强以及T1、T2~5、第1跖骨(m1)、m2、第3跖骨(m3)、第4跖骨(m4)、m5区域的冲量在民族间存在差异(Pm4、m5、足跟内侧(mH)、足跟外侧(LH)区域的接触面积,T1、T2~5、m2区域的压力峰值,T1、m1、m4区域的峰值压强,T1、T2~5、m4区域的平均压强,以及T1、T2~5、m1、m2、m5、mH区域的冲量在民族间存在差异(Pm2)和冲量(T1、T2~5、m1、m2、m4、m5)与民族呈现显著的相关性。世居藏族与移居汉族青年足底压力测试指标存在显著差异,且足底各区域参数的分布规律不同。两个民族的健康青年足底压力分布具有其独特性。

关键词：高海拔民族大学生足底压力步态

Correction of failure in antenna array using matrix pencil technique

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Chinese Physics B 2017年第6期26卷 491-498页

作者： S u Khan m K A Rahim Advanced RF & microwave Research Group Department of Communication Engineering Faculty of Electrical Engineering Universiti Teknologi Malaysia 81310 Skudai Johor Malaysia

In this paper a non-iterative technique is developed for the correction of faulty antenna array based on matrix pencil technique（mPT）. The failure of a sensor in antenna array can damage the radiation power pattern in terms of sidelobes level and nulls. In the developed technique, the radiation pattern of the array is sampled to form discrete power pattern information set. Then this information set can be arranged in the form of hankel matrix（Hm） and execute the singular value decomposition（SVD）. By removing nonprincipal values, we obtain an optimum lower rank estimation of Hm. This lower rank matrix corresponds to the corrected pattern. Then the proposed technique is employed to recover the weight excitation and position allocations from the estimated matrix. Numerical simulations confirm the efficiency of the proposed technique, which is compared with the available techniques in terms of sidelobes level and nulls.

关键词： array correction low rank estimation matrix pencil technique singular value decomposition

Promotion of structural plasticity in area V2 of visual cortex prevents against object recognition memory deficits in aging and Alzheimer's disease rodents

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Neural Regeneration Research 2024年第8期19卷 1835-1841页

作者： Irene Navarro-Lobato mariam masmudi-martín manuel F.López-Aranda Juan F.López-Téllez Gloria Delgado Pablo Granados-Durán Celia Gaona-Romero marta Carretero-Rey Sinforiano Posadas maría E.Quiros-Ortega Zafar u.Khan Laboratory of Neurobiology Centro de Investigaciones Médico Sanitarias(CIMES)University of MalagaMalagaSpain Department of medicine Faculty of MedicineUniversity of MalagaMalagaSpain Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas(CIBERNED) Institute of Health Carlos IIIMadridSpain the Donders Institute for Brain Cognition and Behaviour Radboud UniversityNijmegenThe Netherlands the Brain metastasis Group National Cancer Research Centre(CNIO)MadridSpain the Department of Neurobiology University of California-Los AngelesLos AngelesCAUSA

memory deficit,which is often associated with aging and many psychiatric,neurological,and neurodegenerative diseases,has been a challenging issue for *** till now,all potential drug candidates have failed to produce satisfa ctory ***,in the search for a solution,we found that a treatment with the gene corresponding to the RGS14414protein in visual area V2,a brain area connected with brain circuits of the ventral stream and the medial temporal lobe,which is crucial for object recognition memory(ORm),can induce enhancement of *** this study,we demonstrated that the same treatment with RGS14414in visual area V2,which is relatively unaffected in neurodegenerative diseases such as Alzheimer s disease,produced longlasting enhancement of ORm in young animals and prevent ORm deficits in rodent models of aging and Alzheimer’s ***,we found that the prevention of memory deficits was mediated through the upregulation of neuronal arbo rization and spine density,as well as an increase in brain-derived neurotrophic factor(BDNF).A knockdown of BDNF gene in RGS14414-treated aging rats and Alzheimer s disease model mice caused complete loss in the upregulation of neuronal structural plasticity and in the prevention of ORm *** findings suggest that BDNF-mediated neuronal structural plasticity in area V2 is crucial in the prevention of memory deficits in RGS14414-treated rodent models of aging and Alzheimer’s ***,our findings of RGS14414gene-mediated activation of neuronal circuits in visual area V2 have therapeutic relevance in the treatment of memory deficits.

关键词： behavioral performance brain-derived neurotrophic factor cognitive dysfunction episodic memory memory circuit activation memory deficits memory enhancement object recognition memory prevention of memory loss regulator of G protein signaling

An Integral method for Solving Dynamic Equations with Fluid–Solid Coupling

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Acta mechanica Solida Sinica 2024年第1期37卷 99-108页

作者： Xin Zhang Jie Liu Pu Xue Shuowen Yan Yahao Xu m.S.Zahran School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China School of mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China Department of Civil Engineering Military Technical CollegeCairo 11435Egypt

In this work,a new methodology is presented to mainly solve the fluid–solid interaction(FSI)*** methodology combines the advantages of the Newmark precise integral method(NPIm)and the dual neural network(DNN)*** NPIm is employed to modify the exponential matrix and loading vector based on the DNN integral *** involves incorporating the basic assumption of the Newmark-βmethod into the dynamic equation and eliminating the acceleration term from the dynamic equilibrium *** a result,the equation is reduced to a first-order linear equation ***,the PIm is applied to integrate the system step by step within the *** DNN method is adopted to solve the inhomogeneous term through fitting the integrand and the original function with a pair of neural networks,and the integral term is solved using the Newton–Leibniz *** examples demonstrate that the proposed methodology significantly improves computing efficiency and provides sufficient precision compared to the DNN *** is particularly evident when analyzing large-scale structures under blast loading conditions.

关键词： Newmark precise integral method(NPIm) Dual neural networks(DNN) Fluid-solid interaction(FSI) Dynamic time-history analysis Blast loading

Study of K^(*)(892)^(0)andФ(1020)meson production in proton–proton and Pb–Pb collisions at√S_(NN)=2.76 TeV

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Communications in Theoretical Physics 2021年第2期73卷 89-95页

作者： Y Ali m Ahmed A Arif Q Ali u Tabassam u Rubab m Suleymanov Department of Physics COMSATS UniversityPark RoadIslamabad44000Pakistan Institute for Physical Problems Baku Suate UniversityBakuAZ 1000Azrbajan

In this paper,we describe a study of charged particle yield as a function of pT for K^(*)(892)0 and phgr(1020)mesons in proton–proton(pp)and Pb–Pb collisions at√S_(NN)=2.76 TeV in the central rapidity region of|y|mportant ratio,the nuclear modification factor,to study the effects of the medium in the most central region,i.e.0%–5%*** data simulation,we used the EPOS-LHC and EPOS-1.99 *** check the validity of these models'simulations,we compared the data obtained from these monte Carlo simulation programs with ALICE experimental data for√S_(NN)=2.76 *** was concluded that the models'predictions for the phgr-meson in pp and for the most central Pb-Pb collisions disagreed with the ALICE data,and that the difference increased with *** may be connected with the essential role of collective parton behaviors which could not have been taken into account by the *** K^(*)0 mesons,both programs gave almost the same predictions,and with pT in the interval pT>3 GeV c^(−1),the predictions were very close to the experimental *** models gave higher predictions for the soft pT interval and lower predictions for the hard *** values of the RAA distributions were lower than unity and both models were very close to the ALICE *** is very interesting that the models were not able to describe the pT distributions,but they gave good predictions for their *** may possibly be due to parton collective *** observed some additional suppression of K^(*)0 at low values of pT with respect to phgr-mesons,which may be related to the role of the masses of the particles in soft *** rising trend for R_(AA)in the region from pT=10 GeV c^(−1)to 20 GeV c^(−1) observed by the ALICE experiment was absent for theФ-mesons.

关键词： Quark Gluon Plasma EPOS-LHC nuclear modification factor

microstructural Development of Ti-B Alloyed Layer for hard Tissue Applications

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Journal of materials Science & Technology 2013年第6期29卷 565-572页

作者： A.miklaszewski m.u.Jurczyk m.Jurczyk Institute of materials Science and Engineering Poznan University of TechnologyM.Sklodowska-Curie 5 Sq.60-965 PoznanPoland mother's and Child's Health Division Poznan University of Medical SciencesPolna 3360-535 PoznanPoland

microstructural development was analyzed due to the effect of different sizes of precursor powders during surface plasma alloying modification on titanium surface. Ti-B nano and micropowders with 10 wt% B were deposited onto microcrystalline titanium substrate by plasma alloying. As a result, modified surface layer composed of Ti matrix and TiB borides was obtained. The type of the powder precursor influenced recasting process, possible occurrence of porosity and finally the obtained properties and microstructure of the surface layer. Different morphologies and sizes of TiB phase from micro, submicro to even nano increased the hardness and wear resistance of the obtained surface layers. Discussed results referred to a strong TiB precipitation dispersion provided by a fine elements homogenization during mechanical alloying process. Additionally, results of in vitro test with normal human osteoblast cells revealed proper cellular adhesion to modified surfaces. Scanning electron microscopy observation revealed the influence of gas pore size on culturing osteoblast colony. The proposed surface alloying was an effective method of producing TiB phase dispersed in α-Ti matrix with high hardness, good corrosion resistance and good cytocompatibility. Results confirmed that different types of the precursor powders influenced the properties of the surface layer. TiB phase dispersed in α-Ti matrix layer can offer new structural and biofunctional properties for innovative products in hard tissue applications.

关键词： Titanium TiB phase Nano and micro precursors microstructure Corrosion resistance Cytocompatibility