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Damage response of conventionally reinforced two-way spanning concrete slab under eccentric impacting drop weight loading

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Defence Technology（防务技术） 2023年第1期19卷 12-34页

作者： S.M.Anas mehtab alam Mohd Shariq Department of Civil Engineering Faculty of Engineering and TechnologyJamia Millia Islamia(A Central University)Accredited with grade A++ by NAACNew Delhi110025DelhiIndia Department of Civil Engineering Netaji Subhas University of Technology(West Campus)New Delhi110073DelhiIndia

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 *** due to rock/boulder falls do occur on the structures located especially in hilly *** loadings are not predictable but may cause severe damage to the slab/*** stimulates structural engineers and researchers to investigate and understand the dynamic response of RC structures under such impulsive *** 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/*** 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 *** 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 response using these two models is analyzed and compared with the impact test *** 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 *** reveal that the HJC model gives a little overestimation of peak displacement,maximum acceleration,and damage of the slab while the predictions given by

关键词： RC slabs Impact loading Eccentric impacts Concrete models Finite element analysis Damage profiles Stresses Peak acceleration Failure modes Damage dissipation energy Cracking Drop-weight locations

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Estimating the maximum impact force of dry granular flow based on pileup characteristics

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Journal of Mountain Science 2019年第10期16卷 2435-2452页

作者： XIAO Si-you SU Li-jun JIANG Yuan-jun mehtab alam LI Cheng LIU Dao-chuan Key Laboratory of Mountain Hazards and Earth Surface Processes and Institute of Mountain Hazards andEnvironmentChinese Academy of SciencesChengdu610041China University of Chinese Academy of Sciences Beijing100049China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing100101China Sichuan Highway Planning DesignResearch Institute LtdChengdu610041China

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 *** influence of the interaction between the flowing layer and dead zone on the impact force is *** this study,we classified two impact models with respect to the pileup characteristics of the dead ***,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 *** 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 *** 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 *** results in a decrease in the volume of the dead zone at the moment of maximum NIRF with increases in the slope *** such,the maximum NIRF mainly comprises the instant impact force of the flowing layer,so hydro-dynamic models are effective for estimating the maximum *** models will benefit from further study of the components and distribution of the impact force of dry granular flow.

关键词： Dry granular flow Tilted retaining wall Impact force Discrete element method Pileup height

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基于界面黏结的含根土抗剪强度极限值估算模型

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岩土力学 2021年第8期42卷 2173-2184页

作者：夏鑫姜元俊苏立君 mehtab alam 李佳佳中国科学院水利部成都山地灾害与环境研究所四川成都610041 中国科学院大学北京100049 四川农业大学水利水电学院四川雅安625014

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... 详细信息

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。

关键词：含根土根-土界面黏结强度抗剪强度力学模型

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Location-allocation modeling for emergency evacuation planning with GIS and remote sensing:A case study of Northeast Bangladesh

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Geoscience Frontiers 2021年第3期12卷 169-185页

作者： Mahfuzur Rahman Ningsheng Chen MdMonirul Islam Ashraf Dewan Hamid Reza Pourghasemi Rana Muhammad AliWashakh Nirdesh Nepal Shufeng Tian Hamid Faiz mehtab alam Naveed Ahmed Key Laboratory for Mountain Hazards and Earth Surface Process Institute of Mountain Hazards and Environment(IMHE)Chinese Academy of Sciences(CAS)Chengdu 610041China University of Chinese Academy of Sciences(UCAS) Beijing 100049China Department of Civil Engineering International University of Business Agriculture and Technology(IUBAT)Dhaka 1230Bangladesh School of Earth and Planetary Sciences Curtin UniversityKent StBentleyWA 6102Australia Department of Natural Resources and Environmental Engineering College of AgricultureShiraz UniversityShirazIran School of Architecture Neijiang Normal UniversityNeijiang 641100China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China Global Institute for Interdisciplinary Studies Kathmandu 3084Nepal

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 *** use of location-allocation models(LAMs)for evacuation in regard to flood victims is essential to minimize disaster *** 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)*** of the MLMs and MCDM techniques were assessed considering the area under the receiver operating characteristic(AUROC)*** 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.

关键词： Natural disasters Emergency evacuation centers Flooding Machine learning Multi-criteria decision making Location-allocation model

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Seismic Response and Stability Analysis of Single Hinged Articulated Tower

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Open Journal of Civil Engineering 2013年第4期3卷 234-241页

作者： Prashant Atreya Nazrul Islam mehtab alam Syed Danish Hasan Civil Engineering Department Islamic University Madina KSA Department of Civil Engineering Jamia Millia Islamia University New Delhi India University Polytechnic Aligarh Muslim University Aligarh India

Study of dynamic stability phenomenon in transient systems has always created interest amongst the researchers because of its inherent non-linearities. Offshore structures subjected to wave, earthquake or wind loads or a combination of these loads show non-linear transient behaviour. As oceanic waves are better modelled as stochastic process, there is a need to investigate the stochastic stability of flexible offshore structures as well. Present study has been carried out to determine seismic response of Single Hinged Articulated Tower (SHAT) under different categories of wave loads and earthquake followed by its dynamic stability analysis. Different phases of wave/earthquake loading on SHAT have been explored to investigate dynamic instabilities existing during each phase. Two dimensional phase plots have been used to identify phases of dynamic instability existing within the responses of SHAT under various conditions of loading.

关键词： Single Hinged Articulated Tower Earthquake Time History Phase Plot

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Flooding and its relationship with land cover change, population growth, and road density

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Geoscience Frontiers 2021年第6期12卷 16-35页

作者： 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 Key Laboratory for Mountain Hazards and Earth Surface Process Institute of Mountain Hazards and Environment(IMHE)Chinese Academy of Sciences(CAS)Chengdu 610041China University of Chinese Academy of Sciences(UCAS) Beijing 100049China Department of Civil Engineering International University of Business Agriculture and Technology(IUBAT)Dhaka 1230Bangladesh Academy of Plateau Science and Sustainability Xining 810016China Development Research Initiative Dhaka 1216Bangladesh Department of Natural Resources and Environmental Engineering College of AgricultureShiraz UniversityShiraz 71454Iran School of Architecture Neijiang Normal UniversityNeijiang 641100China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China School of Civil Engineering Central South UniversityChangsha 410075China Chengdu Institute of Geology and Mineral Resources China Geological SurveyChina School of Earth and Planetary Sciences Curtin UniversityKent StBentleyWA 6102Australia

Bangladesh experiences frequent hydro-climatic disasters such as *** disasters are believed to be associated with land use changes and climate ***,identifying the factors that lead to flooding is *** 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 ***,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 *** 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 *** Pearson correlation coefficient for RCF and RD was calculated to be *** findings highlight the significant association between floods and causative *** 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.

关键词： Hydro-climatic disasters Machine learning algorithms Statistical model Ensemble model Relative change in flooding areas

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Neural network study of the nuclear ground-state spin distribution within a random interaction ensemble

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Nuclear Science and Techniques 2024年第3期35卷 216-227页

作者： Deng Liu alam Noor A Zhen-Zhen Qin Yang Lei School of Mathematics and Physics Southwest University of Science and TechnologyMianyang 621010China School of Nuclear Science and Technology Southwest University of Science and TechnologyMianyang 621010China

The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and the corresponding ground-state spins as labels or output *** quantum many-body system problem exceeds the capability of our optimized NNs in terms of accurately predicting the ground-state spin of each sample within the ***,our NN model effectively captured the statistical properties of the ground-state spin because it learned the empirical regularity of the ground-state spin distribution in TBRE,as discovered by physicists.

关键词： Neural network Two-body random ensemble Spin distribution of nuclear ground state

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Erratum to:Estimating the maximum impact force of dry granular flow based on pileup characteristics

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Journal of Mountain Science 2022年第7期19卷 2138-2138页

作者： XIAO Si-you SU Lijun JIANG Yuan-jun mehtab alam LI Cheng LIU Dao-chuan Key Laboratory of Mountain Hazards and Earth Surface Processes and Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu610041China University of Chinese Academy of Sciences Beijing100049China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing100101China Sichuan Highway Planning DesignResearch Institute LtdChengdu610041China

The Acknowledgements chapter is missing in the original article The Acknowledgements chapter should beas *** 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 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).

关键词： jointly Pioneer characteristics

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The link between intracellular calcium signaling and exosomal PD-L1 in cancer progression and immunotherapy

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Genes & Diseases 2024年第1期11卷 321-334页

作者： Md Rakibul alam Md Mizanur Rahman Zhiguo Li Department of Toxicology and Cancer Biology College of MedicineUniversity of KentuckyLexingtonKY 40506USA Department of Medicine(Nephrology) Faculty of Medicine and DentistryUniversity of AlbertaEdmontonAlberta T6E2H7Canada

Exosomes are small membrane vesicles containing microRNA,RNA,DNA fragments,and proteins that are transferred from donor cells to recipient *** cells release exo-somes to reprogram the factors associated with the tumor microenvironment(TME)causing tu-mor metastasis and immune *** evidence revealed that cancer cell-derived exosomes carry immune inhibitory molecule program death ligand 1(PD-L1)that binds with re-ceptor program death protein 1(PD-1)and promote tumor progression by escaping immune ***,some FDA-approved monoclonal antibodies are clinicallyused for cancer treatment by blocking PD-1/PD-L1 *** notable treatment outcomes,some pa-tients show poor drug *** PD-L1 plays a vital role in lowering the treatment response,showing resistance to PD-1/PD-L1 blockage therapy through recapitulating the ef-fect of cell surface *** enhance therapeutic response,inhibition of exosomal PD-L1 is *** signaling is the central regulator of tumorigenesis and can regulate exosome biogenesis and secretion by modulating Rab GTPase family and membrane fusion ***-mune checkpoints are also connected with calcium signaling and calcium channel blockers like amlodipine,nifedipine,lercanidipine,diltiazem,and verapamil were also reported to suppress cellular PD-L1 ***,to enhance the PD-1/PD-L1 blockage therapy response,the reduction of exosomal PD-L1 secretion from cancer cells is in our therapeutic *** this review,we proposed a therapeutic strategy by targeting calcium signaling to inhibit the expression of PD-L1-containing exosome levels that could reduce the anti-PD-1/PD-L1 therapy resistance and increase the patient's drug response rate.

关键词： Calcium signaling CD8^(+)T cells Exosomal PD-L1 Exosomes biogenesis Immunosuppression Immunotherapy

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Effect of Fluidic Diode on Performance of Unidirectional Impulse Turbine

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Journal of Thermal Science 2024年第3期33卷 807-814页

作者： DODDAMANI Hithaish ABDUS Samad MANABU Takao SHINYA Okuhara M M ASHRAFUL alam Department of Ocean Engineering Indian Institute of Technology MadrasChennai600036India Department of Mechanical Engineering National Institute of TechnologyMatsue CollegeShimane6908518Japan Center of Support Practical Education National Institute of TechnologyMatsue CollegeShimane6908518Japan Department of Transportation Engineering Osaka Sangyo UniversityDaito5748530Japan

A pair of unidirectional turbines(UT)can operate in oscillatory airflow without additional ***,this arrangement suffers from poor flow rectification.A fluidic diode(FD)offers variable hydrodynamic resistance based on the flow direction,and this can be coupled with UT to improve flow *** this work,a numerical investigation on the effect of FD with UT is presented using the commercial fluid dynamics software ANSYS Fluent 16.1 with k-ωSST turbulence closure *** domains of UT and FD are numerically validated individually with experimental ***,both are coupled to obtain the combined effect,and these results are compared with the analytical *** was observed that coupling FD with UT improved the unit's performance at the lower flow coefficient(<1),but its performance decreased as the flow coefficient *** to the diode's presence,fluid leaving the turbine experiences higher resistance at a higher flow coefficient,which decreases the overall performance of the combined unit.

关键词： wave energy oscillating water column unidirectional impulse turbine fluidic diode flow rectification

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