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Understanding the role of nano-TiO on the toxicity of Pb on through modeling–Is it additive or synergistic?

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-021-1493-4

摘要:

• A two-compartment model is able to quantify the effect of nano-TiO2 on Pb toxicity.

关键词: Algae     C. dubia     Lead     Nano-TiO2     Synergistic toxicity     Two-compartment toxicokinetic-toxicodynamic model    

受限空间火灾模型研究进展

郑昕,袁宏永

《中国工程科学》 2004年 第6卷 第3期   页码 68-74

摘要:

火灾模型是从工程科学的角度出发,分析研究火灾的发生、发展,烟气蔓延以及火灾对周围环境诸如建筑设备、森林植被及大气环境等影响的数学模型。介绍了广泛应用于建筑物内部受限空间的场、区域、网模型以及经验模型的理论思想与数学方程,分析了4种模型在相应环境下应用的合理性,并对火灾模型的发展做出了展望。

关键词: 受限空间     场模型     区域模型     网模型     场区网模型     经验模型    

火灾环境下钢构件升温过程的模型研究

史聪灵,霍然,李元洲,彭伟,姚斌

《中国工程科学》 2003年 第5卷 第12期   页码 66-72

摘要:

对良好分层情况下的室内火灾进行建模,研究了实际火灾环境下的钢构件升温过程。在全尺寸的实验房间开展了油池火燃烧实验,通过不同的羽流模型和溢流模型,预测室内温度和钢构件温度的变化,并对羽流模型的适用性和影响计算的一些参量做了分析。最后对一个候机厅内钢架结构的零售商店的设定火灾进行构件升温预测。

关键词: 火灾环境     双区模型     钢构件温度     羽流模型    

空调硬卧车内气流组织的数值模拟研究

张登春

《中国工程科学》 2004年 第6卷 第9期   页码 66-72

摘要:

空调车内气流组织研究是车厢内热环境控制的基础,合理的车内气流组织可有效地改善乘客的冷热舒适性。采用k-ε湍流模型对25K型空调硬卧车内气流组织进行了数值模拟,研究了不同送风方式和送风参数下车内空气流场和温度场分布规律,并与实验结果进行了对照,两者基本一致。研究结果对于改善硬卧车内人体冷热舒适性提供了理论依据,对车内气流组织优化设计有指导意义。

关键词: 硬卧车     湍流模型     气流组织     数值模拟    

Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller

Zhiyi YU, Guoyu WANG, Shuliang CAO

《机械工程前沿(英文)》 2009年 第4卷 第1期   页码 53-59 doi: 10.1007/s11465-009-0006-0

摘要: This paper presents an extended two-fluid model based on the Navier-Stokes equations and the standard turbulence model, to simulate the three-dimensional air-water bubbly flow in turbo machinery. In the governing equations, the drag force and added mass force are added and the additional source terms arising from fluctuations of gas volume fraction are considered. The discrete equations are solved using a developed two-phase semi-implicit method for pressure-linked equations, consistent (SIMPLEC) algorithm in body-fitted coordinates with a staggered grid system. Simulation is then carried out for the pure liquid flow and air-water two-phase flow with the inlet gas volume fraction being 15% in a multiphase rotodynamic pump impeller and the pump head performance is predicted. Comparison with experimental results shows the reliability and commonality of the numerical model.

关键词: two-fluid model     multiphase rotodynamic pump     SIMPLEC algorithm     numerical simulation    

Modified landfill gas generation rate model of first-order kinetics and two-stage reaction

Jiajun CHEN , Hao WANG , Na ZHANG ,

《环境科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 313-319 doi: 10.1007/s11783-009-0025-4

摘要: This investigation was carried out to establish a new domestic landfill gas (LFG) generation rate model that takes into account the impact of leachate recirculation. The first-order kinetics and two-stage reaction (FKTSR) model of the LFG generation rate includes mechanisms of the nutrient balance for biochemical reaction in two main stages. In this study, the FKTSR model was modified by the introduction of the outflow function and the organic acid conversion coefficient in order to represent the in-situ condition of nutrient loss through leachate. Laboratory experiments were carried out to simulate the impact of leachate recirculation and verify the modified FKTSR model. The model calibration was then calculated by using the experimental data. The results suggested that the new model was in line with the experimental data. The main parameters of the modified FKTSR model, including the LFG production potential (), the reaction rate constant in the first stage (), and the reaction rate constant in the second stage () of 64.746 L, 0.202 d, and 0.338 d, respectively, were comparable to the old ones of 42.069 L, 0.231 d, and 0.231 d. The new model is better able to explain the mechanisms involved in LFG generation.

关键词: landfill gas (LFG)     generation rate model     first-order kinetics     two-stage reaction     outflow function    

Sustainability performance analysis of environment innovation systems using a two-stage network DEA model

《工程管理前沿(英文)》   页码 425-438 doi: 10.1007/s42524-022-0205-5

摘要: The term environmental innovation system refers to an innovation network composed of enterprises, universities, and research institutions involved in the development and diffusion of environmental technology, with the participation of a government. An environmental innovation system not only exerts important impact on the achievement of carbon neutrality but also affects social and economic activities. Investigations on environmental innovation system performance constantly assume a single-stage independent system while ignoring its internal structure. However, such systems are composed of environmental innovation research and development (R&D) and environmental innovation conversion subsystems. A two-stage data envelopment analysis (DEA) model is developed in this study to analyze the efficiency of Chinese regional environmental innovation system by opening the “black box” and considering shared resources. Empirical results indicated that China presents high overall environmental innovation efficiency although some regions need to improve. Regions with low efficiencies in both environmental innovation R&D (EIR) and environmental innovation conversion (EIC) subsystems should expand their investment in and strengthen the management of environmental innovation resources. Regions with low EIR efficiency should improve the absorption and transformation of environmental innovation achievements. Regions with low EIC efficiency should increase investment in the commercialization of environmental innovation achievements and encourage green economy industries, such as new energy, art, tourism, and environmental protection.

关键词: data envelopment analysis     environmental efficiency     environmental innovation system     shared resources     two-stage structure    

Developing a new model for simultaneous scheduling of two grand projects based on game theory and solvingthe model with Benders decomposition

Loghman PIRI, Vahidreza GHEZAVATI, Ashkan HAFEZALKOTOB

《工程管理前沿(英文)》 2022年 第9卷 第1期   页码 117-134 doi: 10.1007/s42524-020-0115-3

摘要: Grand infrastructure projects, such as dam, power plant, petroleum, and gas industry projects, have several contractors working on them in several independent sub-projects. The concern of reducing the duration of these projects is one of the important issues among various aspects; thus, our aim is to fulfill the requirements by using the game theory approach. In this study, a mixed-integer programming model consisting of game theory and project scheduling is developed to reduce the duration of projects with a minimum increase in costs. In this model, two contractors in successive periods are entered into a step-by-step competition by the employer during dynamic games, considering an exchange in their limited resources. The optimum solution of the game in each stage are selected as the strategy, and the resources during the game are considered to be renewable and limited. The strategy of each contractor can be described as follows: 1) share their resources with the other contractor and 2) not share the resources with the other contractor. This model can act dynamically in all circumstances during project implementation. If a player chooses a non-optimum strategy, then this strategy can immediately update itself at the succeeding time period. The proposed model is solved using the exact Benders decomposition method, which is coded in GAMS software. The results suggest the implementation of four step-by-step games between the contractors. Then, the results of our model are compared with those of the conventional models. The projects’ duration in our model is reduced by 22.2%. The nominal revenue of both contractors has also reached a significant value of 46078 units compared with the relative value of zero units in the original model. Moreover, we observed in both projects the decreases of 19.5%, 20.9%, and 19.7% in the total stagnation of resources of types 1, 2, and 3, respectively.

关键词: project scheduling     resource leveling between projects     constrained resources     game theory     Benders decomposition    

A two-dimensional numerical model for eutrophication in Baiyangdian Lake

Xudong WANG, Shushen ZHANG, Suling LIU, Jingwen CHEN

《环境科学与工程前沿(英文)》 2012年 第6卷 第6期   页码 815-824 doi: 10.1007/s11783-011-0383-6

摘要: Hydrodynamic, physical, and biochemical processes in the Baiyangdian Lake water environment were analyzed comprehensively. An eutrophication eco-dynamics model including the effects of reed resistance on flow was coupled with the hydrodynamics governing equations. An improvement on the Water Quality Analysis Simulation Program (WASP, a modeling system introduced by the US Environmental Protection Agency) is established, which uses the zooplankton kinetic equation. The model simulates water quality constituents associated with eutrophication in the lake, including phytoplankton, zooplankton, nitrogen, phosphorus, dissolved oxygen, and others. Various kinetic coefficients were calibrated using measured data or information from relevant literature, to study eutrophication in the lake. The values calculated by the calibrated model agree well with field data, including ammonia nitrogen, total nitrogen, total phosphorus and dissolved oxygen. Changes related to nutrition and dissolved oxygen during the processes were simulated. The present model describes the temporal variation of water quality in Baiyangdian Lake with reasonable accuracy. Deviations between model-simulated and observed values are discussed. As an ideal tool for environmental management of the lake, this model can be used to predict its water quality, and be used in research to examine the eutrophication process.

关键词: eutrophication     eco-dynamics     hydrodynamics     improved Water Quality Analysis Simulation Program (WASP) model     Baiyangdian Lake    

地铁客室通风板模型数值模拟及实验研究 Article

陶羽, 杨明智, 钱博森, 伍钒, 王田天

《工程(英文)》 2019年 第5卷 第2期   页码 329-336 doi: 10.1016/j.eng.2018.12.007

摘要:

列车客室内流场研究是轨道列车设计及优化中的关键一环。内流场特性对车内温度分布及乘客舒适性有着显著影响。针对内流场的实验研究可获得较准确的结果,但需要大量时间和经济成本。数值模拟相对于实验可在更短时间内获得内流场特性。本文采用两种简化模型(多孔介质模型和多孔阶跃面模型)来提升轨道列车客室内流场数值模拟的计算效率。将两种简化模型及原始模型的数值模拟结果与实验数据进行比较。结果表明,多孔介质模型的结果与原始模型结果以及实验数据吻合得较好,其流场特性参数(温度和速度)的数值误差较小,最大数值误差为4.71%。在原始模型和多孔介质模型的数值模拟结果中,同一参数之间的数值误差在1% 以内。采用多孔介质模型替代原始模型进行地铁列车客室内流场数值模拟,所占用的计算资源相应减少了25%,且其结果保持了很好的准确性。

关键词: 数值模拟     实验     通风板模型     地铁    

零方程湍流模型在列车车厢内气流数值模拟中的应用

杨培志,顾小松

《中国工程科学》 2006年 第8卷 第1期   页码 26-29

摘要:

采用k-ε湍流模型对列车车厢内气流进行数值模拟需要消耗大量的计算时间,为此,提出了采用零方程湍流模型对列车车厢内的气流组织进行数值模拟;分别采用零方程湍流模型与k-ε湍流模型对列车车厢内的空气流动及传热进行了数值计算,经分析比较可知,该两种湍流模型的数值计算结果吻合程度较好,采用零方程湍流模型可大大缩短计算时间,利用其简单、快捷的特点,可以为列车空调系统的工程设计提供简便的数值模拟方法。

关键词: 空调     零方程湍流模型     数值模拟     列车    

有固相析出的多效两段蒸发系统模型与过程模拟

李玲,阮奇

《中国工程科学》 2008年 第10卷 第10期   页码 54-60

摘要:

建立了带有冷凝水闪蒸的有固相析出的多效两段蒸发系统的常规设计数学模型,模型将系统的相平衡关系用回归式表达,使模型可以用计算机编程求解,避免了手工计算结合查相图的烦琐的计算过程;利用矩阵方程具有结构清晰和高度模块化的特点,将系统的物料衡算和热量衡算方程组写成矩阵方程的形式,只要保留或舍弃矩阵方程中的相关块矩阵,模型就能代表没有冷凝水闪蒸或没有固相析出的多效两段蒸发系统常规设计模型;采用迭代法结合矩阵法来求解模型,算例表明,冷凝水闪蒸对多效两段蒸发系统是有效的节能措施,算法收敛速度快、收敛稳定性好。

关键词: 固相析出     多效两段蒸发数学模型     冷凝水闪蒸    

Application of a weakly compressible smoothed particle hydrodynamics multi-phase model to non-cohesive

Rasoul MEMARZADEH, Gholamabbas BARANI, Mahnaz GHAEINI-HESSAROEYEH

《结构与土木工程前沿(英文)》 2018年 第12卷 第3期   页码 412-424 doi: 10.1007/s11709-017-0432-8

摘要:

The subject of present study is the application of mesh free Lagrangian two-dimensional non-cohesive sediment transport model applied to a two-phase flow over an initially trapezoidal-shaped sediment embankment. The governing equations of the present model are the Navier-Stocks equations solved using Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) method. To simulate the movement of sediment particles, the model considers a powerful two-part technique; when the sediment phase has rigid behavior, only the force term due to shear stress in the Navier-Stokes equations is used for simulation of sediment particles’ movement. Otherwise, all the Navier-Stokes force terms are used for transport simulation of sediment particles. In the present model, the interactions between different phases are calculated automatically, even with considerable difference between the density and viscosity of phases. Validation of the model is performed using simulation of available laboratory experiments, and the comparison between computational results and experimental data shows that the model generally predicts well the flow propagation over movable beds, the induced sediment transport and bed changes, and temporal evolution of embankment breaching.

关键词: WCSPH method     non-cohesive sediment transport     rheological model     two-part technique     two-phase dam break    

An efficient two-stage approach for structural damage detection using meta-heuristic algorithms and groupmethod of data handling surrogate model

Hamed FATHNEJAT, Behrouz AHMADI-NEDUSHAN

《结构与土木工程前沿(英文)》 2020年 第14卷 第4期   页码 907-929 doi: 10.1007/s11709-020-0628-1

摘要: In this study, the performance of an efficient two-stage methodology which is applied in a damage detection system using a surrogate model of the structure has been investigated. In the first stage, in order to locate the damage accurately, the performance of the modal strain energy based index for using different numbers of natural mode shapes has been evaluated using the confusion matrix. In the second stage, to estimate the damage extent, the sensitivity of most used modal properties due to damage, such as natural frequency and flexibility matrix is compared with the mean normalized modal strain energy (MNMSE) of suspected damaged elements. Moreover, a modal property change vector is evaluated using the group method of data handling (GMDH) network as a surrogate model during damage extent estimation by optimization algorithm; in this part of methodology, the performance of the three popular optimization algorithms including particle swarm optimization (PSO), bat algorithm (BA), and colliding bodies optimization (CBO) is examined and in this regard, root mean square deviation ( ) based on the modal property change vector has been proposed as an objective function. Furthermore, the effect of noise in the measurement of structural responses by the sensors has also been studied. Finally, in order to achieve the most generalized neural network as a surrogate model, GMDH performance is compared with a properly trained cascade feed-forward neural network (CFNN) with log-sigmoid hidden layer transfer function. The results indicate that the accuracy of damage extent estimation is acceptable in the case of integration of PSO and MNMSE. Moreover, the GMDH model is also more efficient and mimics the behavior of the structure slightly better than CFNN model.

关键词: two-stage method     modal strain energy     surrogate model     GMDH     optimization damage detection    

Two-echelon Emergency Response Problem and Simulation Considering Secondary Disasters

Han-peng Zhang,Yi Liao,Hui-xia Luo

《工程管理前沿(英文)》 2014年 第1卷 第3期   页码 318-321 doi: 10.15302/J-FEM-2014042

摘要: It is necessary for subsequent resource distribution planning that get expected relief time considering secondary disasters after natural disaster. The goal of this research is to develop a two-echelon emergency resource distribution model under condition of secondary disasters. Taking minimal maximize relief time as criterion of relief performance, we developed response strategies and simulation model to get the expected value. Numerical studies of this paper presented the result of response strategies.

关键词: simulation     secondary disasters     two-echelon vehicle routing model    

标题 作者 时间 类型 操作

Understanding the role of nano-TiO on the toxicity of Pb on through modeling–Is it additive or synergistic?

期刊论文

受限空间火灾模型研究进展

郑昕,袁宏永

期刊论文

火灾环境下钢构件升温过程的模型研究

史聪灵,霍然,李元洲,彭伟,姚斌

期刊论文

空调硬卧车内气流组织的数值模拟研究

张登春

期刊论文

Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller

Zhiyi YU, Guoyu WANG, Shuliang CAO

期刊论文

Modified landfill gas generation rate model of first-order kinetics and two-stage reaction

Jiajun CHEN , Hao WANG , Na ZHANG ,

期刊论文

Sustainability performance analysis of environment innovation systems using a two-stage network DEA model

期刊论文

Developing a new model for simultaneous scheduling of two grand projects based on game theory and solvingthe model with Benders decomposition

Loghman PIRI, Vahidreza GHEZAVATI, Ashkan HAFEZALKOTOB

期刊论文

A two-dimensional numerical model for eutrophication in Baiyangdian Lake

Xudong WANG, Shushen ZHANG, Suling LIU, Jingwen CHEN

期刊论文

地铁客室通风板模型数值模拟及实验研究

陶羽, 杨明智, 钱博森, 伍钒, 王田天

期刊论文

零方程湍流模型在列车车厢内气流数值模拟中的应用

杨培志,顾小松

期刊论文

有固相析出的多效两段蒸发系统模型与过程模拟

李玲,阮奇

期刊论文

Application of a weakly compressible smoothed particle hydrodynamics multi-phase model to non-cohesive

Rasoul MEMARZADEH, Gholamabbas BARANI, Mahnaz GHAEINI-HESSAROEYEH

期刊论文

An efficient two-stage approach for structural damage detection using meta-heuristic algorithms and groupmethod of data handling surrogate model

Hamed FATHNEJAT, Behrouz AHMADI-NEDUSHAN

期刊论文

Two-echelon Emergency Response Problem and Simulation Considering Secondary Disasters

Han-peng Zhang,Yi Liao,Hui-xia Luo

期刊论文