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| 1 | 基于界面黏结的含根土抗剪强度极限值估算模型显示文摘目前根系力学固土定量评估模型中缺乏对根-土界面黏结作用的考虑,为提高量化模型精度及适用性,以广泛应用的Wu模型为基础,结合含根土中根系的破坏模式,通过界面黏结强度参数量化根-土界面间的黏结作用,建立了基于界面黏结的含根土抗剪强度极限值估算模型,考虑了含根土中土体应力、根径、根长、根系与剪切方向初始夹角的影响。含根土直剪试验的实测结果均在估算模型计算值范围内,其中根系与剪切方向夹角为45°时实测值接近模型计算最大值,夹角为90°时实测值接近模型计算极限值的平均值。与Wu模型计算值相比,估算模型精度平均提高了5倍。模型参数敏感性分析表明,根系提供的土体附加强度受根系数量参数、尺寸参数及界面黏结强度参数的影响较大。 | 夏鑫 姜元俊 苏立君 MEHTAB Alam 李佳佳 | 2021 | 岩土力学2021，42，8： | 4 |
| 2 | Location-allocation modeling for emergency evacuation planning with GIS and remote sensing:A case study of Northeast Bangladesh显示文摘This work developed models to identify optimal spatial distribution of emergency evacuation centers(EECs)such as schools,colleges,hospitals,and fire stations to improve flood emergency planning in the Sylhet region of northeastern Bangladesh.The use of location-allocation models(LAMs)for evacuation in regard to flood victims is essential to minimize disaster risk.In the first step,flood susceptibility maps were developed using machine learning models(MLMs),including:Levenberg-Marquardt back propagation(LM-BP)neural network and decision trees(DT)and multi-criteria decision making(MCDM)method.Performance of the MLMs and MCDM techniques were assessed considering the area under the receiver operating characteristic(AUROC)curve.Mathematical approaches in a geographic information system(GIS)for four well-known LAM problems affecting emergency rescue time are proposed:maximal covering location problem(MCLP),the maximize attendance(MA),p-median problem(PMP),and the location set covering problem(LSCP).The results showed that existing EECs were not optimally distributed,and that some areas were not adequately served by EECs(i.e.,not all demand points could be reached within a 60-min travel time).We concluded that the proposed models can be used to improve planning of the distribution of EECs,and that application of the models could contribute to reducing human casualties,property losses,and improve emergency operation. | Mahfuzur Rahman Ningsheng Chen MdMonirul Islam Ashraf Dewan Hamid Reza Pourghasemi Rana Muhammad AliWashakh Nirdesh Nepal Shufeng Tian Hamid Faiz Mehtab Alam Naveed Ahmed | 2021 | Geoscience Frontiers2021，12，3： | 3 |
| 3 | Flooding and its relationship with land cover change, population growth, and road density显示文摘Bangladesh experiences frequent hydro-climatic disasters such as flooding.These disasters are believed to be associated with land use changes and climate variability.However,identifying the factors that lead to flooding is challenging.This study mapped flood susceptibility in the northeast region of Bangladesh using Bayesian regularization back propagation(BRBP)neural network,classification and regression trees(CART),a statistical model(STM)using the evidence belief function(EBF),and their ensemble models(EMs)for three time periods(2000,2014,and 2017).The accuracy of machine learning algorithms(MLAs),STM,and EMs were assessed by considering the area under the curve—receiver operating characteristic(AUC-ROC).Evaluation of the accuracy levels of the aforementioned algorithms revealed that EM4(BRBP-CART-EBF)outperformed(AUC>90%)standalone and other ensemble models for the three time periods analyzed.Furthermore,this study investigated the relationships among land cover change(LCC),population growth(PG),road density(RD),and relative change of flooding(RCF)areas for the period between 2000 and 2017.The results showed that areas with very high susceptibility to flooding increased by 19.72%between 2000 and 2017,while the PG rate increased by 51.68%over the same period.The Pearson correlation coefficient for RCF and RD was calculated to be 0.496.These findings highlight the significant association between floods and causative factors.The study findings could be valuable to policymakers and resource managers as they can lead to improvements in flood management and reduction in flood damage and risks. | Mahfuzur Rahman Chen Ningsheng Golam Iftekhar Mahmud Md Monirul Islam Hamid Reza Pourghasemi Hilal Ahmad Jules Maurice Habumugisha Rana Muhammad Ali Washakh Mehtab Alam Enlong Liu Zheng Han Huayong Ni Tian Shufeng Ashraf Dewan | 2021 | Geoscience Frontiers2021，12，6： | 3 |
| 4 | Damage response of conventionally reinforced two-way spanning concrete slab under eccentric impacting drop weight loading显示文摘Reinforced concrete(RC)structures are generally designed to carry quasi-static gravity loads through almost indispensable components namely slab,however,it may be subjected to high intense loads induced from the impact of projectiles generated by the tornado,falling construction equipment,and also from accidental explosions during their construction and service lifespan.Impacts due to rock/boulder falls do occur on the structures located especially in hilly areas.Such loadings are not predictable but may cause severe damage to the slab/structure.It stimulates structural engineers and researchers to investigate and understand the dynamic response of RC structures under such impulsive loading.This research work first investigates the performance of 1000×1000×75 mm^(3)conventionally reinforced two-way spanning normal strength concrete slab with only tension reinforcement(0.88%)under the concentric impact load(1035 N)using the finite element method based computer code,ABAQUS/Explicit-v.6.15.The impact load is delivered to the centroid of the slab using a solid-steel cylindroconical impactor(drop weight)with a flat nose of diameter 40 mm,having a total mass of 105 kg released from a fixed height of 2500 mm.Two popular concrete constitutive models in ABAQUS namely;Holmquist-Johnson-Cook(HJC)and Concrete Damage Plasticity(CDP),with strain rate effects as per fib MODEL CODE 2010,are used to model the concrete material behavior to impact loading and to simulate the damage to the slab.The slab response using these two models is analyzed and compared with the impact test results.The strain rate effect on the reinforcing steel bars has been incorporated in the analysis using the Malvar and Crawford(1998)approach.A classical elastoplastic kinematic idealization is considered to model the steel impactor and support system.Results reveal that the HJC model gives a little overestimation of peak displacement,maximum acceleration,and damage of the slab while the predictions given by the CDP model are in reasonable agreement with the experimental test results/observations available in the open literature.Following the validation of the numerical model,analyses have been extended to further investigate the damage response of the slab under eccentric impact loadings.In addition to the concentric location(P1)of the impacting device,five locations on a quarter of the slab i.e.,two along the diagonal(P2&P3),the other two along the mid-span(P4&P5),and the last one(P6)between P3 and P5,covering the entire slab,are considered.Computational results have been discussed and compared,and the evaluation of the most damaging location(s)of the impact is investigated.It has been found that the most critical location of the impact is not the centroid of the slab but the eccentric one with the eccentricity of 1/6th of the span from the centroid along the mid-span section. | S.M.Anas Mehtab Alam Mohd Shariq | 2023 | Defence Technology(防务技术)2023，19，1： | 1 |
| 5 | Estimating the maximum impact force of dry granular flow based on pileup characteristics显示文摘The maximum normal impact resultant force(NIRF)is usually regarded as the sum of the static earth pressure of the dead zone and the dynamic impact pressure of the flowing layer.The influence of the interaction between the flowing layer and dead zone on the impact force is ignored.In this study,we classified two impact models with respect to the pileup characteristics of the dead zone.Then,we employed the discrete element method to investigate the influences of the pileup characteristics on the impact force of dry granular flow on a tilted rigid wall.If the final pileup height is equal to the critical value,the maximum NIRF can be estimated using a hydrostatic model,because the main contribution to the maximum NIRF is the static earth pressure of the dead zone.If the final pileup height is less than the critical value,however,the particles in the dead zone are squeezed along the slope surface by the impact ofthe flowing layer on the dead zone,and because of shear effects,the flowing layer causes an entrainment in the dead zone.This results in a decrease in the volume of the dead zone at the moment of maximum NIRF with increases in the slope angle.As such,the maximum NIRF mainly comprises the instant impact force of the flowing layer,so hydro-dynamic models are effective for estimating the maximum NIRF.Impact models will benefit from further study of the components and distribution of the impact force of dry granular flow. | XIAO Si-you SU Li-jun JIANG Yuan-jun MEHTAB Alam LI Cheng LIU Dao-chuan | 2019 | Journal of Mountain Science2019，16，10： | 1 |
| 6 | Erratum to:Estimating the maximum impact force of dry granular flow based on pileup characteristics显示文摘The Acknowledgements chapter is missing in the original article The Acknowledgements chapter should beas follows.Acknowledgements The authors give sincere acknowledgement to Strategic Priority Research Program of Chinese Academy of Sciences(XDA 20030301)and the National Natural Science Foundation of China(Grant No.41761144077)for the completion of this research.The research presented in this paper was also jointly supported by the CAS Pioneer Hundred Talents Program and the National Natural Science Foundation of China(Grant No.41502334). | XIAO Si-you SU Lijun JIANG Yuan-jun MEHTAB Alam LI Cheng LIU Dao-chuan | 2022 | Journal of Mountain Science2022，19，7： | 0 |
| 7 | 吉贾尔-帕坦喀喇昆仑公路沿线落石和边坡稳定性数值研究显示文摘在中巴经济走廊的重要通道喀喇昆仑公路(KKH)沿线,由于构造运动和降雨渗透对破碎岩石和边坡稳定性的不利作用,造成了大量落石和不稳定边坡。利用数值软件DIPS、GeoRock 2D和SLIDE对巴基斯坦北部吉贾尔-帕坦喀喇昆仑公路沿线的落石和边坡稳定性进行了数值研究;以喀喇昆仑公路沿线两个主要的易受落石影响的路段为例,研究落石和边坡的失稳机理。对4组节理进行的赤平投影分析表明:两处边坡断面均易发生平面破坏和楔形破坏。基于极限平衡理论,在静力条件下,边坡断面1的安全系数为0.917,处于不稳定状态,边坡断面2的安全系数为1.131,处于欠稳定状态;但在地震条件下,两处断面边坡的安全系数均小于1,处于不稳定状态。研究结果表明,边坡断面1和断面2的落石回弹高度分别为33m和29m。边坡断面1的落石速度在0.5~44m/s,总动能达到1135.099kJ,而边坡断面2的落石具有0.5~40.901m/s的速度和973.012kJ的破坏能力。研究表明,KKH沿线的落石和滑坡具有极大的破坏潜力。 | ALI Izaz 苏立君 ASGHAR Aamir ALAM Mehtab 刘振宇 董志博 FAIZ Hamid | 2021 | 土木与环境工程学报(中英文)2021，43，1： | 0 |
| 8 | Acetylcholinesterase and Cytotoxic Activity of Chemical Constituents of Clutia lanceolata Leaves and its Molecular Docking Study显示文摘Phytochemical investigations of the ethanolic extract of leaves of Clutia lanceolata(Family:Euphorbiaceae)resulted in the isolation of four compounds viz.3,4-dihydroxy-2-methylbenzoic acid(1),2,20-dihydroxy-1,10-binaphthyl(2),1,3,8-trihydroxy-6-methylanthracene-9,10-dione(3)and 5-hydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,4,6-trien-3-one(4).Although all the isolated compounds were known but this was the first report from this plant source.Their structures were established on the basis of chemical and physical evidences viz.elemental analysis,FT-IR,1 H-NMR,13CNMR and mass spectral analysis.Structure of compound 2 and 4 was further authenticated by single-crystal X-ray analysis and density functional theory calculations.The isolated compounds(1–4)were screened for AChE enzyme inhibition assay in which compound 3 and 4 were found to be more potent AChE inhibitor.Molecular docking study of potent AChE inhibitor was performed to find the probable binding mode of the compounds into the active site of receptor.Moreover,the isolated compounds were also screened for in vivo cytotoxicity by brine shrimp lethality assay. | Mehtab Parveen Faheem Ahmad Ali Mohammed Malla Shaista Azaz Mahboob Alam Omer A.Basudan Manuela Ramos Silva Pedro S.Pereira Silva | 2016 | Natural Products and Bioprospecting2016，6，6： | 0 |
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