Shear behavior of steel I-girder with stiffened corrugated web, Part II: Numerical study
作者：
He, Jun;Wang, Sihao;Liu, Yuqing* ;Wang, Dalei* ;Xin, Haohui
期刊：
Thin-Walled Structures ,2020年147:106025 ISSN：0263-8231
通讯作者：
Liu, Yuqing;Wang, Dalei
作者机构：
[He, Jun] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.;[Liu, Yuqing; Wang, Sihao; Liu, YQ; Wang, Dalei] Tongji Univ, Dept Bridge Engn, Shanghai, Peoples R China.;[Xin, Haohui] Delft Univ & Technol, Civil Engn & Geosci, Delft, Netherlands.
通讯机构：
[Liu, YQ; Wang, DL] T;Tongji Univ, Dept Bridge Engn, Shanghai, Peoples R China.
关键词：
Analytical models evaluation;Composite bridge;Finite element analysis;Parametric studies;Shear capacity;Stiffened corrugated steel web
摘要：
For long-span composite bridges with corrugated steel webs, the encased concrete near the intermediate support section increases the weight of the girder, reduces pre-stressing efficiency, and causes difficulties in the construction process. The authors in the companion paper [1] proposed a corrugated steel web with vertical or/and horizontal stiffeners to replace or shorten the length of concrete encasement. In parallel with experimental study described in the companion paper, this paper further investigates the shear performance of proposed stiffened corrugated steel webs by numerical and analytical methods. Firstly, finite element (FE) models considering material nonlinearity, welding residual stress, and geometric imperfection were established and validated against the experimental results. Then the effects of web thickness, corrugation depth, height and thickness of stiffeners on shear strength and failure modes were analyzed based on the validated FE models. Finally, both experimental and numerical shear strength were used to evaluate the applicability of existing calculation methods proposed by different scholars to predict the shear capacity of stiffened corrugated steel web. The comparisons reveal that calculation methods proposed by Hassanein & Kharoob [2] and Leblouba et al. [3] predict the shear capacity of pure corrugated steel web more accurately, and all existing calculation methods underestimate corrugated steel web with vertical stiffeners. Therefore, the analytical model for accurately predicting shear strength of stiffened corrugated steel web need to be developed, which will be investigated in subsequent studies.
语种：
英文
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Chitosan oligosaccharide-based dual pH responsive nano-micelles for targeted delivery of hydrophobic drugs.
作者：
Wang, Yulong* ;Khan, Avik;Liu, Yanxin;Feng, Jing;Dai, Lei;...
期刊：
Carbohydrate Polymers ,2019年223:115061 ISSN：0144-8617
通讯作者：
Wang, Yulong;Ni, Yonghao
作者机构：
[Wang, Yulong; Liu, Yanxin] Changsha Univ Sci & Technol, Sch Chem & Food Engn, Changsha 410004, Hunan, Peoples R China.;[Ni, Yonghao; Wang, Yulong; Liu, Yanxin; Dai, Lei; Feng, Jing; Alam, Nur; Khan, Avik; Wang, Guanhua; Tong, Li] Univ New Brunswick, Dept Chem Engn, Fredericton, NB E3B 5A3, Canada.;[Feng, Jing] Beijing Inst Petrochem Technol, Coll Chem Engn, Beijing 102617, Peoples R China.;[Dai, Lei] Shaanxi Univ Sci & Technol, Coll Bioresources Chem & Mat Engn, Xian 710021, Shaanxi, Peoples R China.;[Ni, Yonghao] POB 4400, Fredericton, NB E3B 5A3, Canada.
通讯机构：
[Wang, Yulong] C;[Ni, Yonghao] P;Changsha Univ Sci & Technol, Sch Chem & Food Engn, Changsha 410004, Hunan, Peoples R China.;POB 4400, Fredericton, NB E3B 5A3, Canada.
关键词：
Chitosan oligosaccharide;Drug delivery;Dual pH responsive nano-micelles (DPRNs);Genistein;Nano-micelles
摘要：
In this study, chitosan oligosaccharide (COS)-vanillin imine (COS-Vani Imine)-based dual pH responsive nanomicelles (DPRNs) were synthesized. The resultant DPRNs were used for encapsulating genistein and its ultimate release upon pH change. The overall concept of DPRNs for the targeted delivery of hydrophobic anticancer drugs was successfully demonstrated. The DPRNs were spherical in shape, nanoscale in dimension (71.2-163.4 nm), with dual pH response. The encapsulation/loading of genistein into DPRNs was achieved and the resultant genistein-loaded DPRNs were stable under the physiological pH ((similar to)7.4); under the cancer cell extracellular pH ((similar to)6.8), the amino groups in COS is protonated, thus becoming positively charged, facilitating their adsorption onto negatively charged cancer cells. Under the cancer cell intracellular pH ((similar to)5.0), the genistein-loaded DPRNs were destroyed as a result of the cleavage of pH sensitive benzoic imine, thereby releasing the loaded genistein.
语种：
英文
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Synthesis and photocatalytic property of V2O5@TiO2 core-shell microspheres towards gaseous benzene
作者：
Li, Yangfan;Wang, Linlin;Li, Zhaolong;Liu, Yueli* ;Peng, Zhuoyin* ;...
期刊：
Catalysis Today ,2019年321:164-171 ISSN：0920-5861
通讯作者：
Liu, Yueli;Peng, Zhuoyin
作者机构：
[Wang, Linlin; Zhou, Min; Zhang, Chao; Li, Zhaolong; Liu, Yueli; Li, Yangfan; Jin, Wei] Wuhan Univ Technol, Sch Mat Sci & Engn, State Key Lab Silicate Mat Architectures, Wuhan 430070, Hubei, Peoples R China.;[Peng, Zhuoyin; Li, Zhaolong] Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Efficient & Clean Energy Utilizat, Changsha 410111, Hunan, Peoples R China.
通讯机构：
[Liu, Yueli] W;[Peng, Zhuoyin] C;Wuhan Univ Technol, Sch Mat Sci & Engn, State Key Lab Silicate Mat Architectures, Wuhan 430070, Hubei, Peoples R China.;Changsha Univ Sci & Technol, Sch Energy & Power Engn, Key Lab Efficient & Clean Energy Utilizat, Changsha 410111, Hunan, Peoples R China.
关键词：
Charge recombination;Gaseous benzene;Photocatalytic performance;V2O5@TiO2 core-shell microspheres
摘要：
In the present work, V2O5 microspheres with the diameters ranging from 1 to 2 μm are prepared by a facile hydrothermal progress, and then V2O5@TiO2 core-shell microspheres are successfully synthesized by a solution method. It is found that the light absorption intensity of V2O5@TiO2 core-shell microspheres is greatly enhanced compared with those of V2O5 microspheres and P25 in UV and visible light ranges. The photodegradation rate towards gaseous benzene of V2O5@TiO2-20% core-shell microspheres is the best one, and it will increase from 27.8% and 10% (pure V2O5 microspheres) to be 100% and 71.8% after 75 min’ irradiation under UV and visible light irradiation, respectively. The reason lies in the fact that the formation of V2O5@TiO2 core-shell microspheres may favor for the light absorption as well as the effective separation of the photoexcited electrons and holes. © 2018 Elsevier B.V.
语种：
英文
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Accurate prediction of potential druggable proteins based on genetic algorithm and Bagging-SVM ensemble classifier
作者：
Lin, Jianying;Chen, Hui;Li, Shan;Liu, Yushuang;Li, Xuan;...
期刊：
Artificial Intelligence in Medicine ,2019年98(Jul.):35-47 ISSN：0933-3657
通讯作者：
Yu, Bin
作者机构：
[Lin, Jianying; Chen, Hui; Li, Shan; Liu, Yushuang; Yu, Bin] Qingdao Univ Sci & Technol, Coll Math & Phys, Qingdao 266061, Shandong, Peoples R China;[Lin, Jianying; Chen, Hui; Li, Shan; Liu, Yushuang; Yu, Bin] Qingdao Univ Sci & Technol, Artificial Intelligence & Biomed Big Data Res Ctr, Qingdao 266061, Shandong, Peoples R China;[Lin, Jianying; Chen, Hui; Li, Xuan] Chinese Acad Sci, Shanghai Inst Biol Sci, Inst Plant Physiol & Ecol, Key Lab Synthet Biol,CAS Ctr Excellence Mol Plant, Shanghai 200032, Peoples R China;[Yu, Bin] Changsha Univ Sci & Technol, Sch Math & Stat, Changsha 410114, Hunan, Peoples R China;[Yu, Bin] Univ Sci & Technol China, Sch Life Sci, Hefei 230027, Anhui, Peoples R China
通讯机构：
[Yu, Bin] Q;Qingdao Univ Sci & Technol, Coll Math & Phys, Qingdao 266061, Shandong, Peoples R China.
关键词：
Druggable proteins;Feature extraction;Genetic algorithm;Support vector machine;Bagging;Ensemble classifier
摘要：
Discovering and accurately locating drug targets is of great significance for the research and development of new drugs. As a different approach to traditional drug development, the machine learning algorithm is used to predict the drug target by mining the data. Because of its advantages of short time and low cost, it has received more and more attention in recent years. In this paper, we propose a novel method for predicting druggable proteins. Firstly, the features of the protein sequence are extracted by combining Chou's pseudo amino acid composition (PseAAC), dipeptide composition (DPC) and reduced sequence (RS), getting the 591 dimension of drug target dataset. Then, the feature information of druggable proteins dataset is selected by genetic algorithm (GA). Finally, we use Bagging ensemble learning to improve SVM classifier to get the final prediction model. The predictive accuracy rate reaches 93.78% by using 5-fold cross-validation and compared with other state-of-the-art predictive methods. The results indicate that the method proposed in this paper has a high reference value for the prediction of potential drug targets, which will successfully play a key role in the drug research and development. The source code and all datasets are available at https://github.com/QUST-AIBBDRC/GA-Bagging-SVM. © 2019 Elsevier B.V.
语种：
英文
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Synthesis and reaction mechanism of an alkali-activated metakaolin-slag composite system at room temperature
作者：
Peng, Hui;Cui, Chao;Liu, Zhen;Cai, C. S.;Liu, Yang*
期刊：
Journal of Materials in Civil Engineering ,2019年31(1) ISSN：0899-1561
通讯作者：
Liu, Yang
作者机构：
[Liu, Yang; Peng, Hui] Changsha Univ Sci & Technol, Sch Civil Engn, Natl Local Joint Engn Lab Technol Long Term Perfo, Changsha 410004, Hunan, Peoples R China.;[Cui, Chao; Liu, Zhen] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;[Cai, C. S.; Liu, Zhen] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.;[Cai, C. S.] Changsha Univ Sci & Technol, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Liu, Yang] C;Changsha Univ Sci & Technol, Sch Civil Engn, Natl Local Joint Engn Lab Technol Long Term Perfo, Changsha 410004, Hunan, Peoples R China.
关键词：
Blast furnace practice;Blast furnaces;Compressive strength;Curing;Fourier transform infrared spectroscopy;Gelation;Geopolymers;Inorganic polymers;Reaction products;Scanning electron microscopy;Temperature;X ray diffraction;Activator module;Ambient temperature curing;Cementitious composites;Curing temperature;Geopolymer;Ground granulated blast furnace slag;Metakaolins;Reaction mechanism;Slags;composite;kaolin;polymer;reaction kinetics;slag;temperature
摘要：
Synthesis of geopolymer using metakaolin (MK) usually requires a relatively high curing temperature, which limits the application of MK-based geopolymers in the practice of civil engineering.With the goal of developing a cementitious composite that can be cured at room temperature, in the present study, ground granulated blast furnace slag powder was incorporated into MK for the synthesis of a geopolymer. With the aid of compressive strength tests, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM), the influence of slag's impact on the consistency, gelling time, and mechanical properties of the gelling system, as well as the reaction mechanism of the composite system, were investigated. The results showed that the incorporation of slag into MK improved the consistency of the slurry and shortened the setting time. A high-strength paste was synthesized successfully using the MK-slag composite system under ambient temperature curing. Results of XRD and FTIR analyses indicated that MK geopolymerization and slag hydration occurred simultaneously in the MK-slag composite system via alkali activation. The structure of hardened paste consists of both C-S-H-type and N-A-S-H-type gels. The activator module and the MK/slag mass ratio were the main factors affecting the strength of the synthesized products: when the slag replacement ratio was no more than 40%, the strength of the reaction products decreased with an increase of the activator module; when the slag replacement ratio reached or exceeded 60%, the strength of the reaction products increased with the increasing activator module. © 2018 American Society of Civil Engineers.
语种：
英文
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High synergistic effects of natural-based tea saponin in intumescent flame-retardant coatings for enhancement of flame retardancy and pyrolysis performance
作者：
Qian, Wei;Li, Xiangzhou* ;Zhou, Jun;Liu, Yanxin;Wu, Zhiping
期刊：
Progress in Organic Coatings ,2019年127:408-418 ISSN：0300-9440
通讯作者：
Li, Xiangzhou
作者机构：
[Liu, Yanxin; Zhou, Jun; Li, Xiangzhou; Wu, Zhiping; Qian, Wei] Cent South Univ Forestry & Technol, Sch Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.;[Qian, Wei] Guangdong Polytech Environm Protect Engn, Nanhai 528216, Foshan, Peoples R China.;[Li, Xiangzhou] State Key Lab Ecol Appl Technol Forest Area South, Changsha 410004, Hunan, Peoples R China.;[Liu, Yanxin] Changsha Univ Sci & Technol, Sch Chem & Bioengn, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Li, Xiangzhou] C;Cent South Univ Forestry & Technol, Sch Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
关键词：
Tea saponin;CTS-IFRCs;Synergistic effects;Multi-stage gas phase flame-retardant mechanism;Pyrolysis kinetic performance
摘要：
Tea saponin intumescent flame-retardant coatings (TS-IFRCs) is a green and high-efficiency flame-retardant coating based on natural-based tea saponin (TS), and has been confirmed with superior flame retardancy. The present study determined and assessed the effects of TS on the flame-retardant mechanism in composite tea saponin intumescent flame-retardant coatings (CTS-IFRCs) through the analysis of TG-DSC, FT-IR, SEM-EDS and pyrolysis kinetics. It has been demonstrated from the results that TS, synergized with other components in CTS-IFRCs, has direct and significant impacts on the char layer microstructure, flame retardancy and pyrolysis performance, these influences contributed to the double effects of TS as a blowing agent in gas phase flame-retardant mechanism, and as a carbon agent in condensed phase flame-retardant mechanism. High synergistic effects of natural-based TS revealed in this study have provided effective theoretical basis for emerging environmentally friendly bio-based flame-retardant materials and explored a new way for the utilization of TS.
语种：
英文
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Preparation and Characterization of Camellia oleifera Nut Shell-based Bioadsorbent and its Application for Heavy Metals Removal
作者：
Liu, Yanxin;Li, Xiangzhou* ;Wang, Yulong;Zhou, Jun;He, Wanting
期刊：
BIORESOURCES ,2019年14(1):234-250 ISSN：1930-2126
通讯作者：
Li, Xiangzhou
作者机构：
[Liu, Yanxin; Zhou, Jun; Li, Xiangzhou] Cent South Univ Forestry & Technol, Sch Mat & Engn, Changsha 410004, Hunan, Peoples R China.;[Liu, Yanxin; Wang, Yulong; He, Wanting] Changsha Univ Sci & Technol, Sch Chem & Bioengn, Changsha 410004, Hunan, Peoples R China.;[Li, Xiangzhou] State Key Lab Ecol Appl Technol Forest Area South, Changsha 410004, Hunan, Peoples R China.;[Liu, Yanxin; Wang, Yulong] Univ New Brunswick, Limerick Pulp & Paper Ctr, Dept Chem Engn, Fredericton, NB E3B 5A3, Canada.
通讯机构：
[Li, Xiangzhou] C;[Li, Xiangzhou] S;Cent South Univ Forestry & Technol, Sch Mat & Engn, Changsha 410004, Hunan, Peoples R China.;State Key Lab Ecol Appl Technol Forest Area South, Changsha 410004, Hunan, Peoples R China.
关键词：
Bioadsorbent;Camellia oleifera nut shell;Heavy metal;Kinetics;Thermodynamics
摘要：
As a renewable agricultural solid waste, Camellia oleifera nut shell (CONS) is often discarded or burned, causing adverse environmental impact and a waste of resources. The purpose of this work was to develop a CONS-based bioadsorbent for the removal of heavy metals. Both CONS and ethanol/NaOH-modified CONS (MCONS) were prepared. The specimens were characterized using physiochemical composition, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX). The effects of pH, initial metal concentration, adsorbent dosage, adsorption time, and temperature on the Cr(VI) and Cu(II) removal were evaluated. The adsorption kinetics, isotherms, and thermodynamics were determined. The MCONS sample had a higher carboxyl group content and surface area than the CONS sample, which helped explain its enhanced adsorption performance of heavy metals. The maximum uptake capacity of Cr(VI) and Cu(II) was 16.39 mg/g and 27.26 mg/g for MCONS, compared with 6.34 mg/g and 9.89 mg/g for CONS. The adsorption kinetics for CONS and MCONS fit well with the pseudo-second-order kinetic model. The adsorption isotherms fit well to the Langmuir model. The thermodynamic analyses revealed that the adsorption process was spontaneous and exothermic. © 2019 North Carolina State University.
语种：
英文
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Evaluating Probabilistic Traffic Load Effects on Large Bridges Using Long-Term Traffic Monitoring Data
作者：
Lu, Naiwei;Ma, Yafei* ;Liu, Yang
期刊：
Sensors ,2019年19(22):5056 ISSN：1424-8220
通讯作者：
Ma, Yafei
作者机构：
[Ma, Yafei; Lu, Naiwei; Liu, Yang] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Liu, Yang] Hunan Univ Sci, Sch Civil Engn, Zhuzhou 412007, Peoples R China.
通讯机构：
[Ma, Yafei] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
structural safety;traffic load;probabilistic extrapolation;bridge engineering;traffic load effect;stochastic traffic flow;level-crossing rate
摘要：
With the steadily growing of global transportation market, the traffic load has increased dramatically over the past decades, which may develop into a risk source for existing bridges. The simultaneous presence of heavy trucks that are random in nature governs the serviceability limit for large bridges. This study investigated probabilistic traffic load effects on large bridges under actual heavy traffic load. Initially, critical stochastic traffic loading scenarios were simulated based on millions of traffic monitoring data in a highway bridge in China. A methodology of extrapolating maximum traffic load effects was presented based on the level-crossing theory. The effectiveness of the proposed method was demonstrated by probabilistic deflection investigation of a suspension bridge. Influence of traffic density variation and overloading control on the maximum deflection was investigated as recommendations for designers and managers. The numerical results show that the congested traffic mostly governs the critical traffic load effects on large bridges. Traffic growth results in higher maximum deformations and probabilities of failure of the bridge in its lifetime. Since the critical loading scenario contains multi-types of overloaded trucks, an effective overloading control measure has a remarkable influence on the lifetime maximum deflection. The stochastic traffic model and corresponding computational framework is expected to be developed to more types of bridges.
语种：
英文
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考虑轴重相关的随机车流荷载效应
作者：
李明;刘扬;杨兴胜
期刊：
浙江大学学报.工学版 ,2019年53(1):78-88 ISSN：1008-973X
通讯作者：
Liu, Y.
作者机构：
长沙理工大学桥梁工程安全控制技术与装备湖南省工程技术研究中心;[杨兴胜] 四川交通职业技术学院;[李明; 刘扬] 长沙理工大学
通讯机构：
Hunan Province Research Center for Safety Control Technology and Equipment of Bridge Engineering, Changsha University of Science and Technology, Changsha, China
关键词：
桥梁工程;荷载效应;随机车流;轴重相关
摘要：
为了给桥梁验算的设计荷载提供参考,基于宜泸高速WIM实测数据,分析随机车流参数尤其是轴重相关性.应用MATLAB平台编制随机车流模拟程序,采用影响线法分析随机车流的荷载效应,探讨考虑轴重相关与不考虑时荷载效应的差别.研究结果表明:轴重具有多峰分布的特点,轴重之间具有较强的相关性,当模拟随机车流时,若不考虑车辆参数的相关性,则会造成较大误差;采用非参数核密度估计-Copula方法,利用t-Copula函数作为连接函数的轴重联合分布函数,可以较准确地描述车辆轴重联合分布;考虑轴重相关情况下的荷载效应代表值比不考虑时高约45%,与实测车流荷载效应代表值更加接近;各车道随机车流对简支梁桥的荷载效应代表值差别不大,但均已超过现行规范公路-I级车道荷载的荷载效应,效应比最大值为1.34.
语种：
中文
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Experimental Investigation of Bond between Near-Surface-Mounted CFRP Strips and Concrete under Freeze-Thawing Cycling
作者：
Peng, Hui;Liu, Yang;Cai, C. S.;Yu, Jun;Zhang, Jianren*
期刊：
Journal of Aerospace Engineering ,2019年32(1) ISSN：0893-1321
通讯作者：
Zhang, Jianren
作者机构：
[Liu, Yang; Zhang, Jianren; Peng, Hui] Changsha Univ Sci & Technol, Sch Civil Engn, Natl Local Joint Engn Lab Technol Long Term Perfo, Changsha 410004, Hunan, Peoples R China.;[Cai, C. S.] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.;[Cai, C. S.] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;[Yu, Jun] Cent S Univ, Sch Civil Engn, Changsha 410075, Hunan, Peoples R China.
通讯机构：
[Zhang, Jianren] C;Changsha Univ Sci & Technol, Sch Civil Engn, Natl Local Joint Engn Lab Technol Long Term Perfo, Changsha 410004, Hunan, Peoples R China.
关键词：
Carbon fiber reinforced plastics;Compressive strength;Concrete additives;Concretes;Debonding;Deterioration;Durability;Fiber reinforced plastics;Freezing;Friction;Frost resistance;High performance concrete;Reducing agents;Reinforced concrete;Reinforced plastics;Reinforcement;Thawing;Air entraining agents;Carbon fiber reinforced polymer;Experimental investigations;Freeze-thaw cycles;High strength concretes;Near surface mounted;Structural strengthening;Water-reducing agents;Bond length
摘要：
The technique of prestressing near-surface-mounted (NSM) carbon fiber-reinforced polymer (CFRP) has good potential and future prospects for structural strengthening due to its improvement of the bond between the CFRP and concrete. However, notably few investigations have been conducted to study the bond durability of the NSM CFRP-concrete interface. The present study was undertaken to increase the understanding of the durability of the bond between the NSM CFRP and concrete under freeze-thaw cycles. Pull-out tests were conducted to investigate the influence of freeze-thaw cycles on the interfacial bond with ordinary concrete and concrete with high strength or additional frost resistance. The mechanism of freeze-thaw cycles degrading the bond of the NSM CFRP is discussed. Additionally, the influence of the distance between concrete edge and groove (edge distance) and the bond length on the bond durability was studied. It was found that, first, freeze-thaw cycling results in a significant decrease in compressive strength of ordinary concrete but a unremarkable degradation of strength of high-strength concrete and concrete with water-reducing agents and admixtures of air-entraining agents. Second, freeze-thaw cycling also leads to a relatively significant decrease in the bond of the NSM CFRP systems with ordinary concrete; however, it has no substantial impact on the bond of specimens of concrete with high strength or frost resistance. This indicates that the deterioration of the bond of NSM CFRP under freeze-thaw cycles is caused by the degradation of concrete. Third, a decrease in the edge distance results in cone-shaped cracks at the loaded end. Finally, when the failure mode remains debonding at the NSM CFRP-concrete interface, the NSM CFRP system with a longer bond length exhibits more significant degradation in bond capacity compared with that with a shorter bond length. This is because the residual friction stress at the debonding interface also decreases due to freeze-thaw cycling; thus, a longer bond length corresponds to a great loss of residual friction force at the debonding zone. © 2018 American Society of Civil Engineers.
语种：
英文
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Probabilistic fatigue life prediction for concrete bridges using Bayesian inference
作者：
Yuan, Ming* ;Liu, Yun;Yan, Donghuang;Liu, Yongming
期刊：
Advances in Structural Engineering ,2019年22(3):765-778 ISSN：1369-4332
通讯作者：
Yuan, Ming
作者机构：
[Yuan, Ming; Yan, Donghuang] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Liu, Yun] Hunan Commun Polytech, Inst Rd & Bridge Engn, Changsha, Hunan, Peoples R China.;[Liu, Yongming] Arizona State Univ, Sch Engn Matter Transport & Energy, Tempe, AZ USA.
通讯机构：
[Yuan, Ming] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
Bayesian network;bridge;concrete;fatigue life prediction;nonlinear
摘要：
A probabilistic fatigue life prediction framework for concrete bridges is proposed in this study that considers the stress history from the construction stage to the operation stage. The proposed fatigue analysis framework combines the fatigue crack growth-based material life prediction model and a nonlinear structural analysis method. A reliability analysis is proposed using the developed probabilistic model to consider various uncertainties associated with the fatigue damage. A Bayesian network is established to predict the fatigue life of a concrete bridge according to the proposed framework. The proposed methodology is demonstrated using an experimental example for fatigue life prediction of a concrete box-girder. Comparison with experimental data of fatigue life shows a satisfactory accuracy using the proposed methodology, and the ratio of the posterior predicted mean (updating time n = 8) to the test value decreases to 33%–1% in the current investigation. © The Author(s) 2018.
语种：
英文
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Interface Debonding Detection of Precast Segmental Concrete Beams (PSCBs) Using Piezoceramic Transducer-Based Active Sensing Approach
作者：
Liu, Yang;Zhang, Ming;Yin, Xinfeng* ;Hei, Chuang;Wang, Lei
期刊：
Mathematical Problems in Engineering ,2019年2019:1-11 ISSN：1024-123X
通讯作者：
Yin, Xinfeng
作者机构：
[Yin, Xinfeng; Wang, Lei; Liu, Yang; Zhang, Ming] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Hei, Chuang] Univ Houston, Dept Mech Engn, Houston, TX 77204 USA.
通讯机构：
[Yin, Xinfeng] C;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
Adhesives;Concrete aggregates;Damage detection;Debonding;Epoxy resins;Frequency domain analysis;Piezoelectric ceramics;Precast concrete;Time domain analysis;Transducers;Actuators and sensors;Concrete specimens;Debonding damage;Experimental research;Interface debonding;Piezoceramic sensors;Piezoceramic transducer;Smart aggregates;Concrete beams and girders
摘要：
An active sensing approach using piezoceramic induced stress wave is proposed to provide monitoring and early warning for the development of interface debonding damage of precast segmental concrete beams (PSCBs). Three concrete specimens with toothed interfaces were fabricated and bonded with high-strength epoxy resin adhesive to form PSCBs. Smart aggregates (SAs) embedded in concrete specimens are used as actuators and sensors. The PSCBs are subjected to periodic loading with hydraulic jack to test the different degrees of debonding damage. The experimental results of time-domain and frequency-domain analysis clearly show that the amplitude of the signal received by the piezoceramic sensor is reduced when debonding crack occurs. The energy analysis and damage index based on wavelet packet can be used to determine the existence and severity of interface debonding damage in PSCBs. The experimental research validates the feasibility of monitoring the interface debonding damage in PSCBs using SA transducers based on active sensing technique. © 2019 Yang Liu et al.
语种：
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Microstructure and microhardness property of the interface between a metakaolin/GGBFS-based geopolymer paste and granite aggregate
作者：
Peng, Hui;Cui, Chao;Cai, C. S.;Liu, Yang;Liu, Zhen*
期刊：
Construction and Building Materials ,2019年221:263-273 ISSN：0950-0618
通讯作者：
Liu, Zhen
作者机构：
[Liu, Yang; Peng, Hui] Changsha Univ Sci & Technol, Natl Local Joint Engn Lab Technol Long Term Perfo, Changsha 410004, Hunan, Peoples R China.;[Cui, Chao; Liu, Yang; Peng, Hui] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;[Cai, C. S.; Liu, Zhen] Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.;[Cui, Chao] Inner Mongolia Univ Technol, Sch Civil Engn, Key Lab Civil Engn Struct & Mech, Hohhot 010051, Peoples R China.
通讯机构：
[Liu, Zhen] L;Louisiana State Univ, Dept Civil & Environm Engn, Baton Rouge, LA 70803 USA.
关键词：
Geopolymer;Metakaolin/GGBFS;Granite aggregate;ITZ;Bond strength
摘要：
The application of geopolymers as an alternative to Portland cement has received significant attention in concrete development due to the promotion of sustainability. Interfacial transition zone (ITZ) has been characterized as the weakest link in ordinary Portland cement concrete and usually deteriorates the mechanical properties and durability of concrete. To further understand the performance of geopolymeric concrete, the microstructure and properties of the interface zone in geopolymeric concrete are investigated in this study. Metakaolin and ground granulated blast-furnace slag (GGBFS) were used as the raw materials for geopolymer synthesis. Cubic splitting tests were conducted to investigate the interfacial bond strength between the geopolymer and the granite aggregate for different activator moduli and liquid/solid ratios. The morphology and mechanical properties of the ITZ between the geopolymer and granite aggregate were studied with the aids of scanning electron microscopy, energy-dispersive X-ray spectroscopy, and microhardness testing. The results indicate that the bond strength between the geopolymer and aggregate is higher than that between the cement paste and granite aggregate, and it decreases with the increase of the activator modulus and liquid/solid ratio. An ITZ was observed between the geopolymer paste and granite aggregate, and its microstructure and chemical components were different from those of the geopolymer. Obvious inhomogeneity can be observed for the ITZ along the aggregate body. The microhardness of the ITZ is lower than that of the geopolymer binder, and an increase in the activator modulus and liquid/solid ratio leads to an increase in the width of the crack in the ITZ and a decrease in the microhardness. © 2019 Elsevier Ltd
语种：
英文
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Finding the informative and concise set through approximate skyline queries
作者：
Yin, Bo* ;Wei, Xuetao* ;Liu, Yonghe
期刊：
Expert Systems with Applications ,2019年119:289-310 ISSN：0957-4174
通讯作者：
Yin, Bo;Wei, Xuetao
作者机构：
[Yin, Bo] ChangSha Univ Sci & Technol, Sch Comp & Commun Engn, Hunan Prov Key Lab Intelligent Proc Big Data Tran, Changsha, Hunan, Peoples R China.;[Wei, Xuetao] Univ Cincinnati, Sch Informat Technol, Cincinnati, OH 45221 USA.;[Wei, Xuetao] Univ Cincinnati, Dept Elect Engn & Comp Syst, Cincinnati, OH 45221 USA.;[Liu, Yonghe] Univ Texas Arlington, Dept Comp Sci & Engn, Arlington, TX 76019 USA.
通讯机构：
[Yin, Bo] C;[Wei, Xuetao] U;ChangSha Univ Sci & Technol, Sch Comp & Commun Engn, Hunan Prov Key Lab Intelligent Proc Big Data Tran, Changsha, Hunan, Peoples R China.;Univ Cincinnati, Sch Informat Technol, Cincinnati, OH 45221 USA.;Univ Cincinnati, Dept Elect Engn & Comp Syst, Cincinnati, OH 45221 USA.
关键词：
Approximate queries;Multi-criteria data analysis;Similarity;Skyline queries
摘要：
Querying databases to search for "best" objects matching users' preferences is a fundamental problem of intelligent systems and applications. The skyline query is an important tool for solving such a best-matching problem from the concept of multi-criteria optimization. However, it has the size problem as the size of the results of a skyline query grows superlinearly with the number of criteria. Here, we propose to find both the informative and concise set of skyline, a refined skyline set without similar objects. The informativeness requires the reduced set to cover the skyline, i.e., for every skyline point in the original dataset, there exists a close point in the reduced set, which help users to understand the skyline in more detail and make a better decision. The conciseness requires the size of the reduced set that can cover the skyline is as smaller as possible, which help users to make a quick decision. Finding both the informative and concise set of skyline will boost the usability of intelligent systems. More specifically, we propose two new skyline queries to find the informative and concise set of skyline: minimum skyline query, and extended minimum skyline query. The main idea is to return the minimum number of approximation objects, in which there is an object within a predefined distance threshold for each skyline object. The difference of the two query types is that the former one selects approximation objects only from skyline set, while the latter one selects from the whole dataset. We present an exact solution which computes minimum skyline in linear time for a 2d-space. As both minimum skyline and extended minimum skyline problems are NP-hard for dimensionality at least three, we present greedy solutions that obtain a 1 + ln R approximation of the optimums. A comprehensive performance evaluation demonstrates that the size of skyline set can be effectively reduced by using the proposed (extended) minimum skyline queries and our proposed algorithms have promising results. (C) 2018 Elsevier Ltd. All rights reserved.
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英文
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Deformation behaviour of AZ31 magnesium alloy sheet hybrid actuating with Al driver sheet and temperature in magnetic pulse forming
作者：
Xu, Junrui* ;Xie, Xueyun;Wen, Zhisheng;Cui, Junjia;Zhang, Xu;...
期刊：
Journal of Manufacturing Processes ,2019年37:402-412 ISSN：1526-6125
通讯作者：
Xu, Junrui;Liu, Yang
作者机构：
[Xie, Xueyun; Wen, Zhisheng; Xu, Junrui; Liu, Yang; Zhu, Daibo] Xiangtan Univ, Minist Educ, Engn Res Ctr Complex Tracks Proc Technol & Equipm, Xiangtan 41105, Peoples R China.;[Xu, Junrui] Xiangtan Univ, Key Lab Welding Robot & Applicat Technol Hunan Pr, Xiangtan 411105, Peoples R China.;[Xu, Junrui] Huazhong Univ Sci & Technol, State Key Lab Mat Proc & Die & Mould Technol, Wuhan, Hubei, Peoples R China.;[Cui, Junjia] Hunan Univ, Coll Mech & Vehicle Engn, State Key Lab Adv Design & Mfg Vehicle Body, Changsha, Hunan, Peoples R China.;[Zhang, Xu] Hunan Univ, Coll Automot & Mech Engn, Changsha Univ Sci & Technol, Changsha, Hunan, Peoples R China.
通讯机构：
[Xu, JR; Liu, Y] X;Xiangtan Univ, Minist Educ, Engn Res Ctr Complex Tracks Proc Technol & Equipm, Xiangtan 41105, Peoples R China.
关键词：
Deformation;Dynamic recrystallization;Grain refinement;Magnesium alloys;Magnetism;Microstructure;Strain rate;Temperature;AZ31 magnesium alloy sheet;Az31 sheets;Deformation behaviour;Driver sheet;Dynamic recrystallization (DRX);Experimental analysis;Increasing temperatures;Magnetic pulse;Magnesium printing plates
摘要：
In this paper, formability of AZ31 sheet in magnetic pulse forming hybrid actuating with driver sheet and temperature were investigated. The effects of discharge parameters, driver sheet and temperature were investigated on bulging by the experimental analysis. Forming height, thickness of AA1060 driver sheet, forming limit curve (FLC), fracture morphology and microstructure were performed to analyze causes of deformation behaviour for driver sheet and temperature. Analysis of driver sheet and temperature effects reveals that the optimum thickness of the driver sheet and temperature are 1 mm and 200 ℃ respectively. The FLC results show increased by increasing temperature from 25 ℃ to 200 ℃ and then decreased by increasing the temperature such as 250 ℃. Compared with quasi-static forming, the temperature effect for formability is unremarkable in magnetic pulse forming with driver sheet. Demonstrating similar drawability and strechability of AZ31 sheet appeared. Microstructure reveals that high strain rate effect, yield strength decreasing (because of temperature effect) and grain refinement are main reasons to affect the formability of AZ31 sheet in magnetic pulse forming with driver sheet and temperature. However, dynamic recrystallization (DRX) is not observed which is usually accompanied at temperatures higher than 150 ℃ in quasi-static forming. © 2018
语种：
英文
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Mechanical characterization of a unidirectional pultruded composite lamina using micromechanics and numerical homogenization
作者：
Xin, Haohui;Mosallam, Ayman;Liu, Yuqing* ;Veljkovic, Milan;He, Jun
期刊：
Construction and Building Materials ,2019年216:101-118 ISSN：0950-0618
通讯作者：
Liu, Yuqing
作者机构：
[Xin, Haohui; Liu, Yuqing] Tongji Univ, Dept Bridge Engn, Shanghai, Peoples R China.;[Xin, Haohui; Veljkovic, Milan] Delft Univ Technol, Fac Geosci & Engn, Delft, Netherlands.;[Mosallam, Ayman] Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA USA.;[He, Jun] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.
通讯机构：
[Liu, Yuqing] T;Tongji Univ, Dept Bridge Engn, Shanghai, Peoples R China.
关键词：
Engineering constants;Micro-mechanic analysis;Mohr-Coulomb plastic criterion;Numerical homogenization;Pultruded unidirectional GFRP lamina
摘要：
In this paper, analytical and numerical homogenization methods are proposed to effectively simulate the macroscopic characteristics of a pultruded composite lamina. A continuum damage model was implemented via user material subroutine to model fiber failure, while the Mohr-Coulomb plastic criterion is employed to model matrix damage. In order to simulate the damage of the fiber-matrix interface, the relationship between traction and displacement is established. The proposed theoretical and numerical models were verified by tensile, compressive, and shear test results. The outcomes of this study indicated that both theoretical, numerical prediction values agree well with experimental verification results confirming the validity of the proposed methodology in providing a reliable reference for structural design of pultruded fiber reinforced polymeric (FRP) composite structures. © 2019 Elsevier Ltd
语种：
英文
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Graphene coated carbon felt as a high-performance electrode for all vanadium redox flow batteries
作者：
Xia, Lu;Zhang, Qingfa;Wu, Chun;Liu, Yaru;Ding, Mei* ;...
期刊：
Surface and Coatings Technology ,2019年358:153-158 ISSN：0257-8972
通讯作者：
Ding, Mei;Cheng, Yuanhang
作者机构：
[Xia, Lu; Wu, Chun; Jia, Chuankun; Ding, Mei; Ye, Jiaye] Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Hunan, Peoples R China.;[Xia, Lu; Ye, Jiaye] Chongqing Univ, Sch Mat Sci & Engn, State Key Lab Mech Transmiss, Chongqing 400044, Peoples R China.;[Zhang, Qingfa] Jining Univ, Dept Chem & Chem Engn, Qufu 273155, Peoples R China.;[Liu, Yaru] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Cheng, Yuanhang] Natl Univ Singapore, Dept Mat Sci & Engn, Singapore, Singapore.
通讯机构：
[Ding, Mei] C;[Cheng, Yuanhang] N;Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Hunan, Peoples R China.;Natl Univ Singapore, Dept Mat Sci & Engn, Singapore, Singapore.
会议名称：
9th International Conference on Technological Advances of Thin Films and Surface Coatings (ThinFilms)
会议时间：
JUL 17-20, 2018
会议地点：
Shenzhen, PEOPLES R CHINA
会议主办单位：
[Xia, Lu;Wu, Chun;Ding, Mei;Ye, Jiaye;Jia, Chuankun] Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Hunan, Peoples R China.^[Xia, Lu;Ye, Jiaye] Chongqing Univ, Sch Mat Sci & Engn, State Key Lab Mech Transmiss, Chongqing 400044, Peoples R China.^[Zhang, Qingfa] Jining Univ, Dept Chem & Chem Engn, Qufu 273155, Peoples R China.^[Liu, Yaru] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.^[Cheng, Yuanhang] Natl Univ Singapore, Dept Mat Sci & Engn, Singapore, Singapore.^[Jia, Chuankun] Nankai Univ, Minist Educ, Key Lab Adv Energy Mat Chem, Tianjin 300071, Peoples R China.
关键词：
Catalyst;Electrode;Graphene;Nafion binder;Vanadium redox flow battery
摘要：
Graphene deposited on the surface of a carbon felt (CF) using a solution coating method has been developed as a high-performance positive electrode for an all vanadium redox flow battery (VRB). A key to obtain excellent electrochemical activity towards the VO2+/VO2+ redox couple is to wrap the CF using the graphene with high specific surface area and superb conductivity. It is found that the dipping times of CF into the graphene/Nafion solution significantly affect its electrochemical activity. The cyclic voltammetry (CV) results indicate that with 5 dipping times, the graphene coated CF (G/CF) exhibits the highest peak current and lowest peak potential difference towards the VO2+/VO2+ redox couple. More importantly, the VRB assembled with our novel G/CF cathodic electrode shows a decreased polarization during charge/discharge process compared with the control VRB with the pristine CF. Consequently, both the voltage efficiency and energy efficiency of the VRB with G/CF electrode have increased compared to the one with pristine CF. Our work provides a simple solution coating process to fabricate graphene modified CF electrode for VRB with high performance and this simple method is believed to be promising in other electrocatalysts applications.
语种：
英文
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Preparation, Characterization, and Antioxidant Activities of Cellulose Nanocrystals/Genistein Nanocomposites
作者：
Wang, Yue;Wang, Yulong* ;Liu, Yanxin;Liu, Qingjian;Jang, Jinwon;...
期刊：
BIORESOURCES ,2019年14(1):336-348 ISSN：1930-2126
通讯作者：
Wang, Yulong
作者机构：
[Wang, Yue; Wang, Yulong; Liu, Yanxin; Han, Junyuan; Liu, Qingjian] Changsha Univ Sci & Technol, Coll Chem & Biol Engn, Changsha 410114, Hunan, Peoples R China.;[Liu, Yanxin] Qilu Univ Technol, Minist Educ China, Key Lab Pulp & Paper Sci & Technol, Jinan 250353, Shandong, Peoples R China.;[Jang, Jinwon] Dalhousie Univ, Fac Med Sci, Halifax, NS B3H 4R2, Canada.
通讯机构：
[Wang, Yulong] C;Changsha Univ Sci & Technol, Coll Chem & Biol Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
Antioxidation activity;Cellulose nanocrystals;Dissolution rate;Genistein;Nanocomposite
摘要：
Genistein (GEN), a typical isoflavone compound, exhibits desirable pharmacological activities, such as antioxidation, anti-inflammatory, anti-angiogenesis, and anti-cancer properties. However, the pharmaceutical application of GEN is limited because of its poor water solubility in aqueous systems. In this study, cellulose nanocrystals (CNCs) and cetyltrimethylammonium bromide (CTAB)-coated CNCs were used as carriers for GEN to improve its dissolution rate and antioxidant activity in aqueous systems. The CNC/GEN and CNC/CTAB/GEN nanocomposites were successfully prepared and characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and X-ray diffraction analysis. The results showed that the nanonized GEN performed better and its crystalline structure decreased because of the formation of the CNC/GEN and CNC/CTAB/GEN nanocomposites. The GEN dissolution rates in the CNC/GEN and CNC/CTAB/GEN nanocomposites increased to 72.1% and 92.5% at 120 min, respectively, compared with that of the original GEN (0.85%). Furthermore, the in vitro antioxidant activity of the GEN, which was evaluated by the hydroxyl radical scavenging efficiency, was remarkably enhanced. Based on the above results, CNCs as nanocarriers are a useful method for improving the dissolution and antioxidant activities of GEN in aqueous system. © 2019 North Carolina State University.
语种：
英文
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Fatigue Reliability Evaluation of Orthotropic Steel Bridge Decks Based on Site-Specific Weigh-in-Motion Measurements
作者：
Lu, Naiwei* ;Liu, Yang;Deng, Yang
期刊：
International Journal of Steel Structures ,2019年19(1):181-192 ISSN：1598-2351
通讯作者：
Lu, Naiwei
作者机构：
[Lu, Naiwei; Liu, Yang] Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;[Lu, Naiwei] Leibniz Univ Hannover, Inst Risk & Reliabil, D-31509 Hannover, Germany.;[Deng, Yang] Beijing Univ Civil Engn & Architecture, Beijing Adv Innovat Ctr Future Urban Design, Beijing 100044, Peoples R China.
通讯机构：
[Lu, Naiwei] C;[Lu, Naiwei] L;Changsha Univ Sci & Technol, Sch Civil Engn, Changsha 410114, Hunan, Peoples R China.;Leibniz Univ Hannover, Inst Risk & Reliabil, D-31509 Hannover, Germany.
关键词：
Bridge decks;Developing countries;Gaussian distribution;Reliability;Sampling;Steel bridges;Stochastic models;Stochastic systems;Suspensions (fluids);Traffic control;Weigh-in-motion (WIM);Welded steel structures;Welding;Welds;Fatigue reliability;Gaussian Mixture Model;Gross vehicle weight;Orthotropic bridge decks;Traffic volumes;Fatigue of materials
摘要：
The fast-growing traffic loads may become a safety hazard for existing bridges especially in developing countries. One of the problems induced by heavy traffic loads is the fatigue damage accumulation of the welded joints in steel bridge decks. This study utilized a stochastic traffic flow model and a novel computational framework for estimating fatigue reliability of orthotropic steel bridge decks using site-specific traffic data. The stochastic traffic flow is demonstrated as an effective approach for converting the probabilistic characteristics of the site-specific traffic data into the fatigue stress spectrum modeling of steel bridge decks. In addition, the traffic growth and control measures can be considered in the stochastic traffic flow for lifetime fatigue reliability estimation of the bridge deck. The proposed computational framework involves a meta-model approximated by neural networks that can greatly reduce the computational effort. Orthotropic steel bridge decks in a long-span suspension bridge is chosen as prototype to illustrate the effective of the stochastic traffic flow model and the computational framework. Numerical results show the following conclusions: firstly, the efficiency and accuracy of the framework is associated with the number of training samples, where approximately 180 training samples is essential for training the 6-types of meta-models; secondly, a annual growth rate of the vehicle weight of 0.5% leads to the fatigue reliability index of the bridge in the 100th year decrease from 5.94 to 0.92. The numerical result may provide a theoretical basis for how to control overloaded trucks for ensuring the bridge safety. © 2018, Korean Society of Steel Construction.
语种：
英文
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A Group-Based Buffer Management for SSD
作者：
Liu, Yan;Xu, Jilong;Xie, Guoqi* ;Zhang, Zaimei;Li, Keqin
期刊：
Journal of Circuits, Systems and Computers ,2019年28(12):1950213 ISSN：0218-1266
通讯作者：
Xie, Guoqi
作者机构：
[Liu, Yan; Xie, Guoqi; Xu, Jilong] Hunan Univ, Coll Comp Sci & Elect Engn, Changsha, Hunan, Peoples R China.;[Zhang, Zaimei] Changsha Univ Sci & Technol, Sch Econ & Management, Changsha, Hunan, Peoples R China.;[Li, Keqin] SUNY Albany, Dept Comp Sci, Albany, NY 12222 USA.
通讯机构：
[Xie, Guoqi] H;Hunan Univ, Coll Comp Sci & Elect Engn, Changsha, Hunan, Peoples R China.
关键词：
Buffer management;Buffer schemes;cache;erase counts;Garbage collection;Sequentiality;write count;Write operations;Electrical engineering
摘要：
Random writes limit the application of SSDs significantly because of their poor latency and high garbage collection overhead. Traditional page-based and block-based buffer management algorithms cannot achieve both high buffer hit ratio and good destage sequentiality at the same time. In this paper, we propose a hybrid scheme called the group-based buffer management (GBBM). To improve buffer hit ratio and decrease write/erase counts, GBBM divides buffer space into Page Region and Group Region. The frequently accessed data pages are placed at the Page Region, while infrequently accessed random written data are grouped in the Group Region. GBBM has been evaluated extensively through simulations. The write counts of GBBM show an average decrease of 12.7% compared with page-level buffer scheme. Compared with hybrid buffer management such as CBM, GBBM decreases the average write/erase count by 14.3%/12.1%. The write hit ratio of GBBM shows a 4.5% improvement as compared with PAB. The proposed GBBM can significantly reduce the number of write operations while maintaining a relatively high buffer hit ratio. © 2019 World Scientific Publishing Company.
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