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Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

《机械工程前沿（英文）》 2011年 第6卷 第4期   页码 383-391 doi: 10.1007/s11465-011-0244-9

摘要：

Finite element models are often used to simulate impact and contact dynamics responses of multibody dynamical systems. However, such a simulation remains very inefficient because very small integration time step must be used when solving the involved differential equations, especially when the involved contact stiffness is high. Although many model reduction techniques have been available to improve the efficiency of finite element based simulations, these techniques cannot be readily applied to contact dynamics simulations due to the high nonlinearity of the contact dynamics models. This paper presents a model reduction approach for finite-element based multibody contact dynamics simulation, based on a modified Lyapunov balanced truncation method. An example is presented to demonstrate that, by applying the model reduction the simulation process is significantly speeded up and the resulting error is bounded within an acceptable level. The performance of the method with respect to some influential factors such as element size, shape and contact stiffness is also investigated.

关键词： contact dynamics     dynamic simulation     model reduction     finite element method    

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Selective reduction of NO by photo-SCR with ammonia in an annular fixed-film photoreactor

YiangChen CHOU, Young KU

《环境科学与工程前沿（英文）》 2012年 第6卷 第2期   页码 149-155 doi: 10.1007/s11783-010-0296-9

摘要： Gaseous NO was photocatalytically reduced at room temperature by photo-assisted selective catalytic reduction (photo-SCR) with ammonia over TiO in this study. NO reduction efficiency and N selectivity were determined from gases composition at the outlet stream of photoreactor. Effect of operating conditions, e.g. light intensity and inlet concentrations of ammonia and oxygen, on the NO reduction efficiency and N selectivity were discussed to determine the feasible operating condition for photocatalytic reduction of NO. Experimental results showed that selective catalytic reduction of NO with ammonia over TiO in the presence of oxygen was a spontaneous reaction in dark. The photoirradiation on the TiO surface caused remarkable photocatalytic reduction of NO to form N , NO , and N O under 254 nm UV illuminations, while almost 90% of N selectivity was achieved in this study. The ammonia and oxygen molecules played the roles of reductant and oxidant for NO reduction and active sites regeneration, respectively. The reduction of NO was found to be increased with the increase of inlet ammonia and oxygen concentrations until specific concentrations because of the limited active sites on the surface of TiO . The kinetic model proposed in this study can be used to reasonably describe the reaction mechanism of photo-SCR.

关键词： photo-SCR     photocatalysis     NO reduction     Eley-Rideal model    

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Model reduction techniques for dynamics analysis of ultra-precision linear stage

Xuedong CHEN, Zhixin LI

《机械工程前沿（英文）》 2009年 第4卷 第1期   页码 64-70 doi: 10.1007/s11465-009-0009-x

摘要： Spring-damping elements are used to simplify the internal interaction in the proposed finite element (FE) model of an ultra-precision linear stage. The dynamics behavior is studied. The comparison between mode shapes from the eigenvalue analysis shows that the components, except the translator, can represent system dynamics characteristics. A reduction approach is used to simplify the system in a dynamic studied. There is little difference between the vibration mode and the response analysis. The experimental modal analysis proves the validity of the reduction approach, which can be generalized to the development and dynamics characteristic study of a complex system model to obviously save computational resource.

关键词： dynamics analysis     air-bearing     linear stage     reduction    

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Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial

《化学科学与工程前沿（英文）》 2022年 第16卷 第12期   页码 1726-1734 doi: 10.1007/s11705-022-2188-5

摘要： Chemical looping reforming of methane is a novel and effective approach to convert methane to syngas, in which oxygen transfer is achieved by a redox material. Although lots of efforts have been made to develop high-performance redox materials, a few studies have focused on the redox kinetics. In this work, the kinetics of SrFeO3−δ–CaO∙MnO nanocomposite reduction by methane was investigated both on a thermo-gravimetric analyzer and in a packed-bed microreactor. During the methane reduction, combustion occurs before the partial oxidation and there exists a transition between them. The weight loss due to combustion increases, but the transition region becomes less inconspicuous as the reduction temperature increased. The weight loss associated with the partial oxidation is much larger than that with combustion. The rate of weight loss related to the partial oxidation is well fitted by the Avrami–Erofeyev equation with n = 3 (A3 model) with an activation energy of 59.8 kJ∙mol‒1. The rate law for the partial oxidation includes a solid conversion term whose expression is given by the A3 model and a methane pressure-dependent term represented by a power law. The partial oxidation is half order with respect to methane pressure. The proposed rate law could well predict the reduction kinetics; thus, it may be used to design and/or analyze a chemical looping reforming reactor.

关键词： chemical looping reforming     SrFeO3−δ/CaO·MnO nanocomposite     reduction kinetics     Avrami–Erofeyev model     pressure-dependent term    

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Fuzzy stochastic long-term model with consideration of uncertainties for deployment of distributed energy

Iraj AHMADIAN,Oveis ABEDINIA,Noradin GHADIMI

《能源前沿（英文）》 2014年 第8卷 第4期   页码 412-425 doi: 10.1007/s11708-014-0315-9

摘要： This paper presents a novel modified interactive honey bee mating optimization (IHBMO) base fuzzy stochastic long-term approach for determining optimum location and size of distributed energy resources (DERs). The Monte Carlo simulation method is used to model the uncertainties associated with long-term load forecasting. A proper combination of several objectives is considered in the objective function. Reduction of loss and power purchased from the electricity market, loss reduction in peak load level and reduction in voltage deviation are considered simultaneously as the objective functions. First, these objectives are fuzzified and designed to be comparable with each other. Then, they are introduced into an IHBMO algorithm in order to obtain the solution which maximizes the value of integrated objective function. The output power of DERs is scheduled for each load level. An enhanced economic model is also proposed to justify investment on DER. An IEEE 30-bus radial distribution test system is used to illustrate the effectiveness of the proposed method.

关键词： component     distributed energy resources     fuzzy optimization     loss reduction     interactive honey bee mating optimization (IHBMO)     voltage deviation reduction     stochastic programming    

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多目标自适应优化模型预测控制——降低氧化锌回转窑的碳排放 Article

Ke Wei, Keke Huang, Chunhua Yang, Weihua Gui

《工程（英文）》 2023年 第27卷 第8期   页码 96-105 doi: 10.1016/j.eng.2023.01.017

摘要：

The zinc oxide rotary kiln, as an essential piece of equipment in the zinc smelting industrial process, is presenting new challenges in process control. China's strategy of achieving a carbon peak and carbon neutrality is putting new demands on the industry, including green production and the use of fewer resources; thus, traditional stability control is no longer suitable for multi-objective control tasks. Although researchers have revealed the principle of the rotary kiln and set up computational fluid dynamics (CFD) simulation models to study its dynamics, these models cannot be directly applied to process control due to their high computational complexity. To address these issues, this paper proposes a multi-objective adaptive optimization model predictive control (MAO-MPC) method based on sparse identification. More specifically, with a large amount of data collected from a CFD model, a sparse regression problem is first formulated and solved to obtain a reduction model. Then, a two-layered control framework including real-time optimization (RTO) and model predictive control (MPC) is designed. In the RTO layer, an optimization problem with the goal of achieving optimal operation performance and the lowest possible resource consumption is set up. By solving the optimization problem in real time, a suitable setting value is sent to the MPC layer to ensure that the zinc oxide rotary kiln always functions in an optimal state. Our experiments show the strength and reliability of the proposed method, which reduces the usage of coal while maintaining high profits. 

关键词： Zinc oxide rotary kiln     Model reduction     Sparse identification     Real-time optimization     Model predictive control     Process control    

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Does environmental infrastructure investment contribute to emissions reduction? A case of China

Xiaoqian SONG, Yong GENG, Ke LI, Xi ZHANG, Fei WU, Hengyu PAN, Yiqing ZHANG

《能源前沿（英文）》 2020年 第14卷 第1期   页码 57-70 doi: 10.1007/s11708-019-0654-7

摘要： Environmental infrastructure investment (EII) is an important environmental policy instrument on responding to greenhouse gas (GHG) emission and air pollution. This paper employs an improved stochastic impact by regression on population, affluence and technology (STRIPAT) model by using panel data from 30 Chinese provinces and municipalities for the period of 2003–2015 to investigate the effect of EII on CO emissions, SO emissions, and PM pollution. The results indicate that EII has a positive and significant effect on mitigating CO emission. However, the effect of EII on SO emission fluctuated although it still contributes to the reduction of PM pollution through technology innovations. Energy intensity has the largest impact on GHG emissions and air pollution, followed by GDP per capita and industrial structure. In addition, the effect of EII on environmental issues varies in different regions. Such findings suggest that policies on EII should be region-specific so that more appropriate mitigation policies can be raised by considering the local realities.

关键词： environmental infrastructure investment (EII)     CO2 emission     SO2 emission     PM2.5 pollution     stochastic impact by regression on population     affluence and technology (STIRPAT) model     governance    

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Electrocatalytic reduction of NO to NH in ionic liquids by P-doped TiO nanotubes

《化学科学与工程前沿（英文）》 2023年 第17卷 第6期   页码 726-734 doi: 10.1007/s11705-022-2274-8

摘要： Designing advanced and cost-effective electrocatalytic system for nitric oxide (NO) reduction reaction (NORR) is vital for sustainable NH3 production and NO removal, yet it is a challenging task. Herein, it is shown that phosphorus (P)-doped titania (TiO2) nanotubes can be adopted as highly efficient catalyst for NORR. The catalyst demonstrates impressive performance in ionic liquid (IL)-based electrolyte with a remarkable high Faradaic efficiency of 89% and NH3 yield rate of 425 μg·h−1·mgcat.−1, being close to the best-reported results. Noteworthy, the obtained performance metrics are significantly larger than those for N2 reduction reaction. It also shows good durability with negligible activity decay even after 10 cycles. Theoretical simulations reveal that the introduction of P dopants tunes the electronic structure of Ti active sites, thereby enhancing the NO adsorption and facilitating the desorption of *NH3. Moreover, the utilization of IL further suppresses the competitive hydrogen evolution reaction. This study highlights the advantage of the catalyst−electrolyte engineering strategy for producing NH3 at a high efficiency and rate.

关键词： nitric oxide reduction reaction     electrcatalysis     ammonia production     phosphorus-doped titania    

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Enhancement of extracellular Cr(VI) reduction for anammox recovery using hydrazine: performance, pathways

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1715-z

摘要：

● N2H4 addition enhanced and recovered anammox performance under Cr(VI) stress.

关键词： Extracellular Cr(VI) reduction     Electron transfer     Anammox     Hydrazine     Cr(VI) inhibition    

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Achieving air pollutant emission reduction targets with minimum abatement costs: An enterprise-level

《环境科学与工程前沿（英文）》 2022年 第16卷 第2期 doi: 10.1007/s11783-021-1459-6

摘要：

• Quantification of efficiency and fairness of abatement allocation are optimized.

关键词： Pollutant emission reduction allocation     Emission reduction measures     Total abatement cost     Economic efficiency     Abatement space    

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Recent advances and challenges of nitrogen/nitrate electro catalytic reduction to ammonia synthesis

《能源前沿（英文）》 doi: 10.1007/s11708-023-0908-2

摘要： The Haber-Bosch process is the most widely used synthetic ammonia technology at present. Since its invention, it has provided an important guarantee for global food security. However, the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution. Under the serious pressure of energy and environment, a green, clean, and sustainable ammonia synthesis route is urgently needed. Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia, which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar, wind, or water energy, without greenhouse gas and toxic gas emissions. Herein, the basic mechanism of the nitrogen reduction reaction (NRR) to ammonia and nitrate reduction reaction (NO3− RR) to ammonia were discussed. The representative approaches and major technologies, such as lithium mediated electrolysis and solid oxide electrolysis cell (SOEC) electrolysis for NRR, high activity catalyst and advanced electrochemical device fabrication for NO3 − RR and electrochemical ammonia synthesis were summarized. Based on the above discussion and analysis, the main challenges and development directions for electrochemical ammonia synthesis were further proposed.

关键词： electrochemical ammonia synthesis     nitrogen     nitrate     nitrogen reduction reaction (NRR) to ammonia     nitrate reduction reaction (NO–3 RR)    

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Strength reduction factors for structural rubbercrete

Bashar S. MOHAMMED,N. J. AZMI

《结构与土木工程前沿（英文）》 2014年 第8卷 第3期   页码 270-281 doi: 10.1007/s11709-014-0265-7

摘要： Many researches have been carried out to study the fresh and hardened properties of concrete containing crumb rubber as replacement to fine aggregate by volume, yet there is no specific guideline has been developed on the mix design of the rubbercrete. The experimental program, which has been developed and reported in this paper, is designed and executed to provide such mix design guidelines. A total of 45 concrete mixes with three different water to cement ratio (0.41, 0.57 and 0.68) were cast and tested for fresh and mechanical properties of rubbercrete such as slump, air content, unit weight, compressive strength, flexural strength, splitting tensile strength and modulus of elasticity. Influence of mix design parameters such as percentage of crumb rubber replacement, cement content, water content, fine aggregate content, and coarse aggregate content were investigated. Three levels of slump value (for conventional concrete mixes) has been selected; low, medium and high slump. In each slump level, water content was kept constant. Equations for the reduction factors (RFs) for compressive strength, flexural strength, splitting tensile strength and modulus of elasticity have been developed. These RFs can be used to design rubbercrete mixes based on the conventional mix (0% crumb rubber content)

关键词： crumb rubber     recycled tire     mix design     reduction factor     strength     modulus elasticity    

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A review of Pt-based electrocatalysts for oxygen reduction reaction

Changlin ZHANG, Xiaochen SHEN, Yanbo PAN, Zhenmeng PENG

《能源前沿（英文）》 2017年 第11卷 第3期   页码 268-285 doi: 10.1007/s11708-017-0466-6

摘要： Development of active and durable electrocatalyst for oxygen reduction reaction (ORR) remains one challenge for the polymer electrolyte membrane fuel cell (PEMFC) technology. Pt-based nanomaterials show the greatest promise as electrocatalyst for this reaction among all current catalytic structures. This review focuses on Pt-based ORR catalyst material development and covers the past achievements, current research status and perspectives in this research field. In particular, several important categories of Pt-based catalytic structures and the research advances are summarized. Key factors affecting the catalyst activity and durability are discussed. An outlook of future research direction of ORR catalyst research is provided.

关键词： oxygen reduction reaction (ORR)     electrocatalysis     platinum catalyst     activity     durability    

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Reduction of CeO

Elena Yu. KONYSHEVA

《化学科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 249-261 doi: 10.1007/s11705-013-1333-6

摘要： Reduction behavior of pure and doped CeO , the multi-phase La Sr CoO ? CeO , La Sr MnO ? CeO , and La Ni Fe O ? CeO composites, was studied under hydrogen containing atmosphere to address issues related to the improvement of electrochemical and catalytic performance of electrodes in fuel cells. The enhanced reduction of cerium oxide was observed initially at 800°C in all composites in spite of the presence of highly reducible transition metal cations that could lead to the increase in surface concentration of oxygen vacancies and generation of the electron enriched surface. Due to continuous reduction of cerium oxide in La Sr CoO ? CeO and La Sr MnO ? CeO (up to 10 h) composites the redox activity of the Ce /Ce pair could be suppressed and additional measures are required for reversible spontaneous regeneration of Ce . After 3 h exposure to H -Ar at 800°C the reduction of cerium oxides and perovskite phases in La Ni Fe O ? CeO composites was diminished. The extent of cerium oxide involvement in the reduction process varies with time, and depends on its initial deviation from oxygen stoichiometry (that results in the larger lattice parameter and the longer pathway for O transport through the fluorite lattice), chemical origin of transition metal cations in the perovskite, and phase diversity in multi-phase composites.

关键词： reduction of cerium oxide     composites     perovskites     catalyst under hydrogen containing atmosphere    

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Scale up of reactors for carbon dioxide reduction

《化学科学与工程前沿（英文）》 2023年 第17卷 第1期   页码 116-122 doi: 10.1007/s11705-022-2178-7

摘要： In recent times there has been a great deal of interest in the conversion of carbon dioxide into more useful chemical compounds. On the other hand, the translation of these developments in electrochemical reduction of carbon dioxide from the laboratory bench to practical scale remains an underexplored topic. Here we examine some of the major challenges, demonstrating some promising strategies towards such scale-up, including increased electrode area and stacking of electrode pairs in different configurations. We observed that increasing the electrode area from 1 to 10 cm2 led to only a 4% drop in current density, with similarly small penalties realised when stacking sub-cells together.

关键词： CO2 reduction     electrochemical cell     electrosynthesis     upscaling    

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标题 作者 时间 类型 操作

Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

期刊论文

Selective reduction of NO by photo-SCR with ammonia in an annular fixed-film photoreactor

YiangChen CHOU, Young KU

期刊论文

Model reduction techniques for dynamics analysis of ultra-precision linear stage

Xuedong CHEN, Zhixin LI

期刊论文

Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial

期刊论文

Fuzzy stochastic long-term model with consideration of uncertainties for deployment of distributed energy

Iraj AHMADIAN,Oveis ABEDINIA,Noradin GHADIMI

期刊论文

多目标自适应优化模型预测控制——降低氧化锌回转窑的碳排放

Ke Wei, Keke Huang, Chunhua Yang, Weihua Gui

期刊论文

Does environmental infrastructure investment contribute to emissions reduction? A case of China

Xiaoqian SONG, Yong GENG, Ke LI, Xi ZHANG, Fei WU, Hengyu PAN, Yiqing ZHANG

期刊论文

Electrocatalytic reduction of NO to NH in ionic liquids by P-doped TiO nanotubes

期刊论文

Enhancement of extracellular Cr(VI) reduction for anammox recovery using hydrazine: performance, pathways

期刊论文

Achieving air pollutant emission reduction targets with minimum abatement costs: An enterprise-level

期刊论文

Recent advances and challenges of nitrogen/nitrate electro catalytic reduction to ammonia synthesis

期刊论文

Strength reduction factors for structural rubbercrete

Bashar S. MOHAMMED,N. J. AZMI

期刊论文

A review of Pt-based electrocatalysts for oxygen reduction reaction

Changlin ZHANG, Xiaochen SHEN, Yanbo PAN, Zhenmeng PENG

期刊论文

Reduction of CeO

Elena Yu. KONYSHEVA

期刊论文

Scale up of reactors for carbon dioxide reduction

期刊论文