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A rate-dependent Prandtl-Ishlinskii model for piezoelectric actuators using the dynamic envelope function

Meiju YANG,Chunxia LI,Guoying GU,Limin ZHU

《机械工程前沿（英文）》 2015年 第10卷 第1期   页码 37-42 doi: 10.1007/s11465-015-0326-1

摘要：

In this paper, a novel rate-dependent Prandtl-Ishlinskii (P-I) model is proposed to characterize the rate-dependent hysteresis nonlinearity of piezoelectric actuators. The new model is based on a modified rate-dependent play operator, in which a dynamic envelope function is introduced to replace the input function of the classical play operator. Moreover, a dynamic density function is utilized in the proposed P-I model. The parameters of the proposed model are identified by a modified particle swarm optimization algorithm. Finally, experiments are conducted on a piezo-actuated nanopositioning stage to validate the proposed P-I model under the sinusoidal inputs. The experimental results show that the developed rate-dependent P-I model precisely characterize the rate-dependent hysteresis loops up to 1000 Hz.

关键词： piezoelectric actuators     hysteresis     Prandtl-Ishlinskii     rate-dependent    

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Effect of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete

Alireza DANESHYAR, Hamid MOHAMMADNEZHAD, Mohsen GHAEMIAN

《结构与土木工程前沿（英文）》 2021年 第15卷 第2期   页码 346-363 doi: 10.1007/s11709-021-0694-z

摘要： Seismic modeling of massive structures requires special caution, as wave propagation effects significantly affect the responses. This becomes more crucial when the path-dependent behavior of the material is considered. The coexistence of these conditions renders numerical earthquake analysis of concrete dams challenging. Herein, a finite element model for a comprehensive nonlinear seismic simulation of concrete gravity dams, including realistic soil–structure interactions, is introduced. A semi-infinite medium is formulated based on the domain reduction method in conjunction with standard viscous boundaries. Accurate representation of radiation damping in a half-space medium and wave propagation effects in a massed foundation are verified using an analytical solution of vertically propagating shear waves in a viscoelastic half-space domain. A rigorous nonlinear finite element model requires a precise description of the material response. Hence, a microplane-based anisotropic damage–plastic model of concrete is formulated to reproduce irreversible deformations and tensorial degeneration of concrete in a coupled and rate-dependent manner. Finally, the Koyna concrete gravity dam is analyzed based on different assumptions of foundation, concrete response, and reservoir conditions. Comparison between responses obtained based on conventional assumptions with the results of the presented comprehensive model indicates the significance of considering radiation damping and employing a rigorous constitutive material model, which is pursued for the presented model.

关键词： soil–structure interaction     massed foundation     radiation damping     anisotropic damage    

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考虑时变效应的水电工程运行安全风险分析方法

张社荣,严磊

《中国工程科学》 2011年 第13卷 第12期   页码 51-55

摘要：

针对水电工程风险因子的时变特性，用随机过程的方法模拟结构抗力与荷载作用，分析水电工程结构特性与运行方式，综合运用改进层次分析法、时变可靠度理论和风险率阈值，建立水电工程运行安全风险率评估模型。以土石坝工程为算例，详细展示时变风险率评估方法的分析流程。算例表明，工程运行安全风险率与服役时间及设计标准有着密切关系；考虑时变效应，风险率随时间推移而逐渐增大，其与设计标准的交点反映结构技术性使用寿命。应用文章提出的评估模型，预测运行期风险率变化趋势，可为水电工程的安全运行和风险决策提供科学依据。

关键词： 水电工程运行安全     风险分析     风险率评估     时变可靠度     改进层次分析法    

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Data-driven approach to solve vertical drain under time-dependent loading

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 696-711 doi: 10.1007/s11709-021-0727-7

摘要： Currently, the vertical drain consolidation problem is solved by numerous analytical solutions, such as time-dependent solutions and linear or parabolic radial drainage in the smear zone, and no artificial intelligence (AI) approach has been applied. Thus, in this study, a new hybrid model based on deep neural networks (DNNs), particle swarm optimization (PSO), and genetic algorithms (GAs) is proposed to solve this problem. The DNN can effectively simulate any sophisticated equation, and the PSO and GA can optimize the selected DNN and improve the performance of the prediction model. In the present study, analytical solutions to vertical drains in the literature are incorporated into the DNN–PSO and DNN–GA prediction models with three different radial drainage patterns in the smear zone under time-dependent loading. The verification performed with analytical solutions and measurements from three full-scale embankment tests revealed promising applications of the proposed approach.

关键词： vertical drain     artificial neural network     time-dependent loading     deep learning network     genetic algorithm     particle swarm optimization    

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Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

《结构与土木工程前沿（英文）》 2016年 第10卷 第1期   页码 112-120 doi: 10.1007/s11709-015-0322-x

摘要： Corrosion of embedded rebars is a classical deterioration mechanism of reinforced concrete structures exposed to chloride environments. Such environments can be attributed to the presence of seawater, deicing or sea-salts, which have high concentrations of chloride ion. Chloride ingress into concrete, essential for inducing rebar corrosion, is a complex interaction between many physical and chemical processes. The current study proposes two chloride ingress parameter models for fly ash concrete, namely: 1) surface chloride content under tidal exposure condition; and 2) chloride binding. First, inconsistencies in surface chloride content and chloride binding models reported in literature, due to them not being in line with past research studies, are pointed out. Secondly, to avoid such inconsistencies, surface chloride content and chloride binding models for fly ash concrete are proposed based upon the experimental work done by other researchers. It is observed that, proposed models are simple, consistent and in line with past research studies reported in literature.

关键词： binding isotherms     chloride ingress     concrete     fly ash     surface chloride content    

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GDF15 negatively regulates chemosensitivity via TGFBR2-AKT pathway-dependent metabolism in esophageal

《医学前沿（英文）》 2023年 第17卷 第1期   页码 119-131 doi: 10.1007/s11684-022-0949-7

摘要： Treating patients with esophageal squamous cell carcinoma (ESCC) is challenging due to the high chemoresistance. Growth differentiation factor 15 (GDF15) is crucial in the development of various types of tumors and negatively related to the prognosis of ESCC patients according to our previous research. In this study, the link between GDF15 and chemotherapy resistance in ESCC was further explored. The relationship between GDF15 and the chemotherapy response was investigated through in vitro and in vivo studies. ESCC patients with high levels of GDF15 expression showed an inferior chemotherapeutic response. GDF15 improved the tolerance of ESCC cell lines to low-dose cisplatin by regulating AKT phosphorylation via TGFBR2. Through an in vivo study, we further validated that the anti-GDF15 antibody improved the tumor inhibition effect of cisplatin. Metabolomics showed that GDF15 could alter cellular metabolism and enhance the expression of UGT1A. AKT and TGFBR2 inhibition resulted in the reversal of the GDF15-induced expression of UGT1A, indicating that TGFBR2-AKT pathway-dependent metabolic pathways were involved in the resistance of ESCC cells to cisplatin. The present investigation suggests that a high level of GDF15 expression leads to ESCC chemoresistance and that GDF15 can be targeted during chemotherapy, resulting in beneficial therapeutic outcomes.

关键词： GDF15     esophageal squamous cell carcinoma     chemoresistance     cellular metabolism     TGFBR2     AKT    

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Analysis of dispatching rules in a stochastic dynamic job shop manufacturing system with sequence-dependent

Pankaj SHARMA,Ajai JAIN

《机械工程前沿（英文）》 2014年 第9卷 第4期   页码 380-389 doi: 10.1007/s11465-014-0315-9

摘要：

Stochastic dynamic job shop scheduling problem with consideration of sequence-dependent setup times are among the most difficult classes of scheduling problems. This paper assesses the performance of nine dispatching rules in such shop from makespan, mean flow time, maximum flow time, mean tardiness, maximum tardiness, number of tardy jobs, total setups and mean setup time performance measures viewpoint. A discrete event simulation model of a stochastic dynamic job shop manufacturing system is developed for investigation purpose. Nine dispatching rules identified from literature are incorporated in the simulation model. The simulation experiments are conducted under due date tightness factor of 3, shop utilization percentage of 90 % and setup times less than processing times. Results indicate that shortest setup time (SIMSET) rule provides the best performance for mean flow time and number of tardy jobs measures. The job with similar setup and modified earliest due date (JMEDD) rule provides the best performance for makespan, maximum flow time, mean tardiness, maximum tardiness, total setups and mean setup time measures.

关键词： scheduling     stochastic dynamic job shop     sequence-dependent setup times     dispatching rule     simulation    

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Numerical analysis of vehicle-bridge coupling vibration concerning nonlinear stress-dependent damping

Pengfei LI; Jinquan ZHANG; Shengqi MEI; Zhenhua DONG; Yan MAO

《结构与土木工程前沿（英文）》 2022年 第16卷 第2期   页码 239-249 doi: 10.1007/s11709-021-0804-y

摘要： Damping is known to have a considerable influence on the dynamic behavior of bridges. The fixed damping ratios recommended in design codes do not necessarily represent the complicated damping characteristics of bridge structures. This study investigated the application of stress-dependent damping associated with vehicle-bridge coupling vibration and based on that investigation proposed the stress-dependent damping ratio. The results of the investigation show that the stress-dependent damping ratio is significantly different from the constant damping ratio (5%) defined in the standard specification. When vehicles travel at speeds of 30, 60, and 90, the damping ratios of the bridge model are 3.656%, 3.658%, and 3.671%, respectively. The peak accelerations using the regular damping ratio are 18.9%, 21.3%, and 14.5% of the stress-dependent damping ratio, respectively. When the vehicle load on the bridge is doubled, the peak acceleration of the mid-span node increases by 5.4 times, and the stress-related damping ratio increases by 2.1%. A corrugated steel-web bridge is being used as a case study, and the vibration response of the bridge is compared with the measured results. The acceleration response of the bridge which was calculated using the stress-dependent damping ratio is significantly closer to the measured acceleration response than that using the regular damping ratio.

关键词： vehicle-bridge vibration system     dynamic analysis     stress-dependent damping     energy dissipation    

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Time-dependent metabolomics uncover dynamic metabolic adaptions in MCF-7 cells exposed to bisphenol A

《环境科学与工程前沿（英文）》 2023年 第17卷 第1期 doi: 10.1007/s11783-023-1604-5

摘要：

● Metabolomic temporal profiling of cells exposed to xenobiotics.

关键词： Metabolomics     BPA     MCF-7     Temporal profiling     Metabolic adaption     Dysregulation correlation    

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The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1411-9

摘要：

• Actual SAORs was determined using MLVSS and temperature.

关键词： Specific ammonia oxidation rate     Sequencing batch reactor     Biomass     Temperature coefficient     Model simulation    

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Use of float consumption rate in resource leveling of construction projects

Atilla DAMCI, Gul POLAT, Firat Dogu AKIN, Harun TURKOGLU

《工程管理前沿（英文）》 2022年 第9卷 第1期   页码 135-147 doi: 10.1007/s42524-020-0118-0

摘要： The management of resources has been claimed to be as important as scheduling methods. Inefficiency in managing resources may bring about severe delays and cost overruns caused by resource shortages in some cases and/or idle resources in others. Therefore, resources should be utilized efficiently to prevent project failures. Resource leveling is one of the approaches that are used for the management of resources. It aims to minimize fluctuations, peaks, and valleys in resource utilization without changing the completion time of a project and the number of resources required. Although the main principle behind traditional resource leveling is achieving an even flow of resources while the original project duration remains unchanged, the literature supports the need to develop an efficient model that discriminates among the activities that are selected for participation in resource leveling. For this purpose, this study has developed a model that considers the float consumption rates of activities in resource leveling. The float consumption rate is the percentage that is set to determine the maximum amount of float which will be consumed to shift the start time of the activity. The proposed model allows a scheduler to assign float consumption rates to each activity that can be used during the resource leveling procedure. When the required information is inputted, the proposed model automatically changes the required daily resources as it shifts the noncritical activities along their available total float times. The proposed model is expected to minimize the likelihood of severe delays and cost overruns. The model is demonstrated by constructing a network and its resource utilization histograms.

关键词： resource management     resource leveling     float consumption rate     scheduling    

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China’s carbon neutrality: an extensive and profound systemic reform

《环境科学与工程前沿（英文）》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1614-3

摘要：

● China has pledged ambitious carbon peak and neutrality goals for mitigating global climate change.

关键词： Carbon neutrality     Energy structure     Technology-dependent society     Coordinated mitigation for air pollutants and CO2    

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Modeling temperature and moisture dependent emissions of carbon dioxide and methane from drying dairy

Enzhu HU, Pakorn SUTITARNNONTR, Markus TULLER, Scott B. JONES

《农业科学与工程前沿（英文）》 2018年 第5卷 第2期   页码 280-286 doi: 10.15302/J-FASE-2018215

摘要： Greenhouse gas emissions due to biological degradation processes of animal wastes are significant sources of air pollution from agricultural areas. The major environmental controls on these microbe-induced gas fluxes are temperature and moisture content. The objective of this study was to model the effects of temperature and moisture content on emissions of CO and CH during the ambient drying process of dairy manure under controlled conditions. Gas emissions were continuously recorded over 15 d with paired fully automated closed dynamic chambers coupled with a Fourier Transformed Infrared gas analyzer. Water content and temperature were measured and monitored with capacitance sensors. In addition, on days 0, 3, 6, 9, 12 and 15, pH, moisture content, dissolved organic carbon and total carbon (TC) were determined. An empirical model derived from the Arrhenius equation confirmed high dependency of carbon emissions on temperature and moisture content. Results indicate that for the investigated dairy manure, 6.83% of TC was lost in the form of CO and 0.047% of TC was emitted as CH . Neglecting the effect of temperature, the moisture contents associated with maximum gas emissions were estimated as 0.75 and 0.79 g·g for CO and CH , respectively.

关键词： carbon dioxide     dairy manure     methane     moisture     temperature    

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Cofactor engineering in cyanobacteria to overcome imbalance between NADPH and NADH: A mini review

Jongmoon Park,Yunnam Choi

《化学科学与工程前沿（英文）》 2017年 第11卷 第1期   页码 66-71 doi: 10.1007/s11705-016-1591-1

摘要： Cyanobacteria can produce useful renewable fuels and high-value chemicals using sunlight and atmospheric carbon dioxide by photosynthesis. Genetic manipulation has increased the variety of chemicals that cyanobacteria can produce. However, their uniquely abundant NADPH-pool, in other words insufficient supply of NADH, tends to limit their production yields in case of utilizing NADH-dependent enzyme, which is quite common in heterotrophic microbes. To overcome this cofactor imbalance and enhance cyanobacterial fuel and chemical production, various approaches for cofactor engineering have been employed. In this review, we focus on three approaches: (1) utilization of NADPH-dependent enzymes, (2) increasing NADH production, and (3) changing cofactor specificity of NADH-dependent enzymes from NADH to NADPH.

关键词： NADH-dependent enzyme     NADPH-dependent enzyme     transhydrogenase     site-directed mutagenesis     enzyme engineering    

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One-dimensional consolidation of over-consolidated soil under time-dependent loading

XIE Kanghe, WANG Kun, CHEN Guohong, HU Anfeng

《结构与土木工程前沿（英文）》 2008年 第2卷 第1期   页码 67-72 doi: 10.1007/s11709-008-0009-7

摘要： The problem of one-dimensional consolidation of over-consolidated saturated soil under time-dependent loading was studied based on semi-analytical method. The relevant computer code was developed by FORTRAN programming, and one-dimensional consolidation behavior of over-consolidated soil was investigated. It is shown that, unlike this described by traditional Terzaghi’s consolidation theory, the rate of excess pore water pressure dissipation is different from that of settlement developing. The magnitude of load and that of pre-consolidation pressure as well as the loading rate has all significant influence on consolidation. With the increasing of pre-consolidation pressure and loading rate, the rate of consolidation increases correspondingly. However, an increase in load will slow down the consolidation rate.

关键词： different     FORTRAN programming     Terzaghi ’     pre-consolidation     magnitude    

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标题 作者 时间 类型 操作

A rate-dependent Prandtl-Ishlinskii model for piezoelectric actuators using the dynamic envelope function

Meiju YANG,Chunxia LI,Guoying GU,Limin ZHU

期刊论文

Effect of seismic wave propagation in massed medium on rate-dependent anisotropic damage growth in concrete

Alireza DANESHYAR, Hamid MOHAMMADNEZHAD, Mohsen GHAEMIAN

期刊论文

考虑时变效应的水电工程运行安全风险分析方法

张社荣,严磊

期刊论文

Data-driven approach to solve vertical drain under time-dependent loading

期刊论文

Chloride binding and time-dependent surface chloride content models for fly ash concrete

S. MUTHULINGAM,B. N. RAO

期刊论文

GDF15 negatively regulates chemosensitivity via TGFBR2-AKT pathway-dependent metabolism in esophageal

期刊论文

Analysis of dispatching rules in a stochastic dynamic job shop manufacturing system with sequence-dependent

Pankaj SHARMA,Ajai JAIN

期刊论文

Numerical analysis of vehicle-bridge coupling vibration concerning nonlinear stress-dependent damping

Pengfei LI; Jinquan ZHANG; Shengqi MEI; Zhenhua DONG; Yan MAO

期刊论文

Time-dependent metabolomics uncover dynamic metabolic adaptions in MCF-7 cells exposed to bisphenol A

期刊论文

The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic

期刊论文

Use of float consumption rate in resource leveling of construction projects

Atilla DAMCI, Gul POLAT, Firat Dogu AKIN, Harun TURKOGLU

期刊论文

China’s carbon neutrality: an extensive and profound systemic reform

期刊论文

Modeling temperature and moisture dependent emissions of carbon dioxide and methane from drying dairy

Enzhu HU, Pakorn SUTITARNNONTR, Markus TULLER, Scott B. JONES

期刊论文

Cofactor engineering in cyanobacteria to overcome imbalance between NADPH and NADH: A mini review

Jongmoon Park,Yunnam Choi

期刊论文

One-dimensional consolidation of over-consolidated soil under time-dependent loading

XIE Kanghe, WANG Kun, CHEN Guohong, HU Anfeng

期刊论文