检索结果-南通市图书馆

Modeling the collapse of the Plasco *** I:Reconstruction of fire

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Building Simulation 2022年第4期15卷 583-596页

作者： Aatif Ali Khan Ramakanth Veera Venkata Domada Xinyan Huang Mustesin Ali Khan asif usmani Department of Building Services Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina Research Institute for Sustainable Urban Development The Hong Kong Polytechnic UniversityKowloonHong KongChina

In recent years,fires in tall buildings have become more frequent,which costs billions of dollars each year and the loss of many human *** facade fire in the Grenfell tower made the structure uninhabitable,and the collapse of the three World Trade Center(WTC)towers is the total structural failure caused by *** such events,no well-defined methodology exists to reconstruct both fire and structural behaviors and carrys out the forensic investigation of a building *** Part I paper collects the evidence of the Plasco Building fire and generates a coherent timeline to reconstruct the fire *** vertical and horizontal fire spread of the building is reconstructed using computational fluid dynamics(CFD)fire modeling and calibrated against the evidence *** spatio-temporal temperature history from the fire modeling provides realistic fire scenarios to simulate the structural *** fire simulation results are used as boundary conditions to be transferred to a finite element analysis tool for a detailed structural analysis to determine the likely collapse mechanism of the Plasco Building in Part *** methodology presented in this paper to reconstruct the fire can also guide the structural fire safety engineers to improve the building fire-safety and life-safety strategies.

关键词： building fire safety high-rise buildings fire investigation fire modeling structure failure

油罐车火灾下钢-混凝土组合梁桥结构响应研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

防灾减灾工程学报 2016年第3期36卷 444-452页

作者：李国强许炎彬 asif usmani 同济大学土木工程学院防灾国家重点实验室上海200092 同济大学土木工程学院上海200092 爱丁堡大学工程学院

采用数值模拟方法,研究钢-混凝土组合梁式公路桥在大型车辆火灾下的结构响应,考察桥梁形式、火灾工况及荷载比的影响。首先以规范给定的烃类火灾升温曲线及CFD模拟实际油罐车火灾所得到的升温曲线作为温度边界条件,用ABAQUS建立了8个有... 详细信息

采用数值模拟方法,研究钢-混凝土组合梁式公路桥在大型车辆火灾下的结构响应,考察桥梁形式、火灾工况及荷载比的影响。首先以规范给定的烃类火灾升温曲线及CFD模拟实际油罐车火灾所得到的升温曲线作为温度边界条件,用ABAQUS建立了8个有限元模型进行计算,得出了构件内部温度场,发现实际火灾下斜交桥受火跨最高温度低于正交桥的,但整体温度更高;实际火灾较规范火灾下结构升温更快,最高温度更高;随后以受火升温结果作为温度荷载,通过恒载升温分析,考察了共计18个案例的结构响应,发现正交桥和斜交桥在火灾下的破坏模式有较大差别,前者出现不适于继续承载的变形,同时伴随着远端支座腹板屈曲的局部破坏,而后者主要体现为远端支座腹板严重屈曲;最后提出了针对钢-混凝土组合梁桥抗火措施和设计思路的建议。

关键词：钢-混凝土组合梁桥车辆火灾参数化分析受火升温结构响应

基于OpenSees的火灾下钢结构连续性倒塌分析

在线全文

学校读者我要写书评

暂无评论

防灾减灾工程学报 2015年第1期35卷 1-5页

作者：姜健 asif usmani 李国强同济大学土木工程学院上海200092 爱丁堡大学工程与环境学院同济大学土木工程防灾国家重点实验室上海200092

主要研究了火灾下平面钢框架的连续性倒塌模式和机制。应用OpenSees软件,对某5跨8层平面钢框架结构模型进行数值分析,研究了荷载比、梁柱刚度比和火灾场景对结构倒塌模式的影响。结果表明,随着荷载比的增大,结构倒塌模式由侧向倾倒式倒... 详细信息

主要研究了火灾下平面钢框架的连续性倒塌模式和机制。应用OpenSees软件,对某5跨8层平面钢框架结构模型进行数值分析,研究了荷载比、梁柱刚度比和火灾场景对结构倒塌模式的影响。结果表明,随着荷载比的增大,结构倒塌模式由侧向倾倒式倒塌变为整体下沉式倒塌;当梁柱刚度比较小时,由于梁的悬链性效应,使结构发生偏向受火开间的侧向位移直至倒塌(弱梁机制),当梁的刚度比较大时,破坏首先发生在框架底层柱,结构呈整体下沉式倒塌(强梁机制);火灾中水平和竖向分布易分别引起结构局部和整体的倒塌。

关键词： OpenSees 钢结构抗火连续性倒塌荷载比梁柱刚度比火灾场景

Finite element analysis of non-newtonian flow:theory and software

在线全文

学校读者我要写书评

暂无评论

Cartesian Product Based Transfer Learning Implementation for Brain Tumor Classification

1999年

作者： Hou-Cheng Huang Zheng-Hua Li and asif S. usmani

来源：畅想之星图书光盘版（南... 评论

在线全文

畅想之星图书光盘版（南通市图书馆镜像）

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第11期73卷 4369-4392页

作者： Irfan Ahmed usmani Muhammad Tahir Qadri Razia Zia asif Aziz Farheen Saeed Electronic Engineering Department Sir Syed University of Engineering&TechnologyKarachi75300Pakistan Department of Computer Science Bahria University Karachi CampusKarachi75260Pakistan Christus Trinity Clinic TexasUSA

Knowledge-based transfer learning techniques have shown good performance for brain tumor classification,especially with small ***,to obtain an optimized model for targeted brain tumor classification,it is challenging to select a pre-trained deep learning(DL)model,optimal values of hyperparameters,and optimization algorithm(solver).This paper first presents a brief review of recent literature related to brain tumor ***,a robust framework for implementing the transfer learning technique is *** the proposed framework,a Cartesian product matrix is generated to determine the optimal values of the two important hyperparameters:batch size and learning *** extensive exercise consisting of 435 simulations for 11 state-of-the-art pre-trained DL models was performed using 16 paired hyperparameters from the Cartesian product matrix to input the model with the three most popular solvers(stochastic gradient descent with momentum(SGDM),adaptive moment estimation(ADAM),and root mean squared propagation(RMSProp)).The 16 pairs were formed using individual hyperparameter values taken from literature,which generally addressed only one hyperparameter for optimization,rather than making a grid for a particular *** proposed framework was assessed using a multi-class publicly available dataset consisting of glioma,meningioma,and pituitary *** assessment shows that ResNet18 outperforms all other models in terms of accuracy,precision,specificity,and recall(sensitivity).The results are also compared with existing state-of-the-art research work that used the same *** comparison was mainly based on performance metric“accuracy”with support of three other parameters“precision,”“recall,”and“specificity.”The comparison shows that the transfer learning technique,implemented through our proposed framework for brain tumor classification,outperformed all existing *** the best of our knowledge,the proposed framework is a

关键词： Deep transfer learning Cartesian product hyperparameter optimization magnetic resonance imaging(MRI) brain tumor classification

Predicting minimum fluidization velocities of multi-component solid mixtures

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2013年第3期11卷 309-316页

作者： Mohammad asif Chemical Engineering Department King Saud University

Employing well-established mixing rules for mean properties, appropriate expressions are derived for predicting minimum fluidization velocities of multi-component solid mixtures in terms of mono- component values for the velocity and the bed voidage at incipient fluidization. Based on flow regime and the mixing level of constituent species, it is found that these relationships differ significantly from each other, whether related to size-different or density-different mixtures. For mixed beds of size-different mixtures, the effect of volume contraction is accounted for by the mean voidage term, which is absent for segregated beds. Incorporating the volume-change of mixing leads to values of the mixture minimum fluidization velocities even lower than corresponding values for segregated bed, thus conforming to the trend reported in the literature. Size-different mixtures exhibit flow regime dependence irrespective of whether the bed is mixed or segregated. On the other hand, the mixing of constituent species does not affect the minimum fiuidization velocity of density-different mixtures, as the difference in the expres- sions for a segregated and a mixed system is rather inconsequential. Comparison with experimental data available in the literature is made to test the efficacy of the minimum fluidization velocity expressions derived here.

关键词： Minimum fluidization velocity Multi-component solid mixtures Flow regime Bed void fraction Volume-change of mixing

'SoS Call' at the Other Edge of Chaos

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2016年第1期29卷 133-150页

作者： MAHMOOD asif Institute of Business & Management University of Engineering and Technology

The focus of this study is to understand and pave the way to build theory of System of Systems(SoS).The authors try to marshal the established thoughts and develop new insights to shed light on the *** the research thrashes the proposed rudimentary concepts,yet they are important to caste clarity to lay the concrete foundation for the emerging concept of *** first part of the paper discusses about the conceptual milieu of *** tries to help resolve their identity crisis by proposing two edges of *** and monolithic systems self-organize at two opposite *** the research work defines SoS locus on extended system of systems methodology(E-SoSM) framework,and dissects it to decode its contradictory and aberrant *** this understanding,the second part traces out the incapacitation of traditional military techniques for asymmetric warfare,typifying with a friendly fire incident of the current Afghan *** through this lens,conjures up that military SoS and anti SoS(enemy) fight to annihilate each other during the clashes of systems of systems in the theater of war.

关键词： Complex system of systems edges of chaos emergence guerrilla warfare self-organization

Effect of volume-contraction on incipient fluidization of binary-solid mixtures

在线全文

学校读者我要写书评

暂无评论

Particuology 2011年第2期9卷 101-106页

作者： Mohammad asif Chemical Engineering Department King Saud University

Towards the development of a predictive model for computing the minimum fluidization velocity, the volume-contraction phenomenon arising from the mixing of unequal solid species is accounted for in the prediction of the bed void fraction of binary-solid mixtures at the incipient fluidization conditions. Com- parison with experimental data obtained from the literature clearly shows that significantly improved predictions are obtained except for cases where the stratification pattern whether arising from the slow defluidization or the difference in the densities of the two species affects the mixing of the constituent species.

关键词： Binary solid mixture Bed void fraction Volume-contraction Minimum fluidization velocity

Understanding the low temperature electrochemistry of magnesium-lithium hybrid ion battery in all-phenyl-complex solutions

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2021年第5期30卷 383-390页

作者： Muhammad Rashad Muhammad asif School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003JiangsuChina Bernal Institute Department of Chemical SciencesUniversity of LimerickLimerick V94 T9PXIreland

Magnesium-lithium hybrid ion batteries have emerged as a new class of energy storage systems owing to dendrite free cycling of magnesium anode and possibility of practice of numerous conventional lithium *** present work,we used hybrid ion strategy to analyze the performance of lithium titanate based lithium cathode,magnesium metal anode,and all-phenyl complex(APC)electrolytes at different temperatures(25℃,10℃,0℃,-10℃,and-20℃).The hybrid ion battery exhibited excellent rate performance(228 m Ah g^(-1)/20 m A g^(-1) and 163 mAh g^(-1)/1000 mA g^(-1))with stable voltage plateaus at 0.90 and 0.75 V,which corresponds to specific energy of 178 Wh kg^(-1) at room temperature(25℃).Experimental results revealed that APC-THF solutions have strong potential to suppress the freezing of electrolyte solutions owing to low boiling point of *** low temperature electrochemical testing revealed the reversible capacities of 213.4,165.5,143.8,133.2 and 78.56 mAh g^(-1) at 25,10,0,-10,and-20℃,***,ex-situ XRD,SEM,and EIS tests were carried out to understand the reaction kinetics of both Mg2+and Li+ions inside the lithium titanate *** hope this work will shed light on low temperature prospective of electrochemical devices for use in cold environments.

关键词： Mg ion battery Mg-Li hybrid ion batteries Electrochemical properties Low temperature Energy storage