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Life-cycle cost analysis of optimal timing of pavement preservation

Zilong WANG,Hao WANG

《结构与土木工程前沿(英文)》 2017年 第11卷 第1期   页码 17-26 doi: 10.1007/s11709-016-0369-3

摘要: Optimal application of pavement preservation or preventive maintenance is critical for highway agencies to allocate the limited budget for different treatments. This study developed an integrated life-cycle cost analysis (LCCA) model to quantify the impact of pavement preservation on agency cost and vehicle operation cost (VOC) and analyzed the optimal timing of preservation treatments. The international roughness index (IRI) data were extracted from the long-term pavement performance (LTPP) program specific pavement studies 3 (SPS-3) to determine the long-term effectiveness of preservation treatments on IRI deterioration. The traffic loading and the initial IRI value significantly affects life extension and the benefit of agency cost caused by pavement preservation. The benefit in VOC is one to two orders greater in magnitude as compared to the benefit in agency cost. The optimal timing calculated based on VOC is always earlier than the optimal timing calculated based on agency cost. There are considerable differences among the optimal timing of three preservation treatments.

关键词: pavement preservation     life-cycle cost analysis     agency cost     vehicle operation cost    

Optimal Timing and Recycling Operation Mode for Electro-Mechanical Products Active Remanufacturing

Wang Gao,Tao Li,Shi-tong Peng,Liang Wang,Hong-chao Zhang

《工程管理前沿(英文)》 2016年 第3卷 第2期   页码 115-122 doi: 10.15302/J-FEM-2016019

摘要: The uncertainties of remanufactured products in multi-life cycle service, such as injury and restoration process route, are comprehensively analyzed in the present study from perspectives of cost and the environment. Based on life cycle assessment method and the life cycle cost analysis, the optimal timing model of active remanufacturing for electro-mechanical products is established considering these uncertainties. In addition, regarding the active remanufacturing as its guidance, this study explores the economic efficiency and corresponding operation mode of electro-mechanical products when recycling in the optimal timing. To validate the optimal timing model for electro-mechanical products active remanufacturing, a specific type of product is taken as a case study with mathematical statistics method and Monte Carlo simulation.

关键词: electro-mechanical products     active remanufacturing     optimal timing     reverse logistics     recycling mode    

Effects of fuel combination and IVO timing on combustion and emissions of a dual-fuel HCCI combustion

Xin LIANG, Jianyong ZHANG, Zhongzhao LI, Jiabo ZHANG, Zhen HUANG, Dong HAN

《能源前沿(英文)》 2020年 第14卷 第4期   页码 778-789 doi: 10.1007/s11708-020-0698-8

摘要: This paper experimentally and numerically studied the effects of fuel combination and intake valve opening (IVO) timing on combustion and emissions of an n-heptane and gasoline dual-fuel homogeneous charge compression ignition (HCCI) engine. By changing the gasoline fraction (GF) from 0.1 to 0.5 and the IVO timing from –15°CA ATDC to 35°CA ATDC, the in-cylinder pressure traces, heat release behaviors, and HC and CO emissions were investigated. The results showed that both the increased GF and the retarded IVO timing delay the combustion phasing, lengthen the combustion duration, and decrease the peak heat release rate and the maximum average combustion temperature, whereas the IVO timing has a more obvious influence on combustion than GF. HC and CO emissions are decreased with reduced GF, advanced IVO timing and increased operational load.

关键词: homogeneous charge compression ignition     dual-fuel     n-heptane     gasoline     intake valve opening timing    

Effect of ignition timing and hydrogen fraction on combustion and emission characteristics of natural

WANG Jinhua, HUANG Zuohua, LIU Bing, ZENG Ke, YU Jinrong, JIANG Deming

《能源前沿(英文)》 2008年 第2卷 第2期   页码 194-201 doi: 10.1007/s11708-008-0035-0

摘要: An experimental study on the combustion and emission characteristics of a direct-injection spark-ignited engine fueled with natural gas/hydrogen blends under various ignition timings was conducted. The results show that ignition timing has a significant influence on engine performance, combustion and emissions. The interval between the end of fuel injection and ignition timing is a very important parameter for direct-injection natural gas engines. The turbulent flow in the combustion chamber generated by the fuel jet remains high and relative strong mixture stratification is introduced when decreasing the angle interval between the end of fuel injection and ignition timing giving fast burning rates and high thermal efficiencies. The maximum cylinder gas pressure, maximum mean gas temperature, maximum rate of pressure rise and maximum heat release rate increase with the advancing of ignition timing. However, these parameters do not vary much with hydrogen addition under specific ignition timing indicating that a small hydrogen fraction addition of less than 20% in the present experiment has little influence on combustion parameters under specific ignition timing. The exhaust HC emission decreases while the exhaust CO concentration increases with the advancing of ignition timing. In the lean combustion condition, the exhaust CO does not vary much with ignition timing. At the same ignition timing, the exhaust HC decreases with hydrogen addition while the exhaust CO and CO do not vary much with hydrogen addition. The exhaust NO increases with the advancing of ignition timing and the behavior tends to be more obvious at large ignition advance angle. The brake mean effective pressure and the effective thermal efficiency of natural gas/hydrogen mixture combustion increase compared with those of natural gas combustion when the hydrogen fraction is over 10%.

Multi-stage dual replica bit-line delay technique for process-variation-robust timing of lowvoltageSRAMsense

Shou-biao TAN,Wen-juan LU,Chun-yu PENG,Zheng-ping LI,You-wu TAO,Jun-ning CHEN

《信息与电子工程前沿(英文)》 2015年 第16卷 第8期   页码 700-706 doi: 10.1631/FITEE.1400439

摘要: A multi-stage dual replica bit-line delay (MDRBD) technique is proposed for reducing access time by suppressing the sense-amplifier enable (SAE) timing variation of low voltage static random-access memory (SRAM) applications. Compared with the traditional technique, this strategy, using statistical theory, reduces the timing variation by using multi-stage ideas, meanwhile doubling the replica bit-line (RBL) capacitance and discharge path simultaneously in each stage. At a supply voltage of 0.6 V, the simulation results show that the standard deviations of the SAE timing and cycle time with the proposed technique are 69.2% and 47.2%, respectively, smaller than that with a conventional RBL delay technique in TSMC 65 nm CMOS technology (Taiwan Semiconductor Manufacturing Company, Taiwan).

关键词: Process-variation-robust     Sense amplifier (SA)     Replica bit-line (RBL) delay     Timing variation    

Smart product design for automotive systems

A. Galip ULSOY

《机械工程前沿(英文)》 2019年 第14卷 第1期   页码 102-112 doi: 10.1007/s11465-019-0527-0

摘要: Automobiles evolved from primarily mechanical to electro-mechanical, or mechatronic, vehicles. For example, carburetors have been replaced by fuel injection and air-fuel ratio control, leading to order of magnitude improvements in fuel economy and emissions. Mechatronic systems are pervasive in modern automobiles and represent a synergistic integration of mechanics, electronics and computer science. They are smart systems, whose design is more challenging than the separate design of their mechanical, electronic and computer/control components. In this review paper, two recent methods for the design of mechatronic components are summarized and their applications to problems in automotive control are highlighted. First, the combined design, or co-design, of a smart artifact and its controller is considered. It is shown that the combined design of an artifact and its controller can lead to improved performance compared to sequential design. The coupling between the artifact and controller design problems is quantified, and methods for co-design are presented. The control proxy function method, which provides ease of design as in the sequential approach and approximates the performance of the co-design approach, is highlighted with application to the design of a passive/active automotive suspension. Second, the design for component swapping modularity (CSM) of a distributed controller for a smart product is discussed. CSM is realized by employing distributed controllers residing in networked smart components, with bidirectional communication over the network. Approaches to CSM design are presented, as well as applications of the method to a variable-cam-timing engine, and to enable battery swapping in a plug-in hybrid electric vehicle.

关键词: mechatronics     automotive control     co-design     component swapping modularity     active suspensions     variable camshaft timing engine     plug-in hybrid electric vehicle    

A global synthesis of the effectiveness and ecological impacts of management interventions for species

《环境科学与工程前沿(英文)》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1741-x

摘要:

Spartina abundance decreases over time by chemical control.

关键词: Plant invasion     Biodiversity     Meta-analysis     Restoration     Salt marshes     Treatment timing    

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 473-486 doi: 10.1007/s11709-020-0608-5

摘要: Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted. However, these previous studies did not consider the effects of climate change, such as acceleration in the deterioration of durability, on mixture design. This study presents a procedure for the optimal mixture design of ternary blended concrete considering climate change and durability. First, the costs of CO emissions and material are calculated based on the concrete mixture and unit prices. Total cost is equal to the sum of material cost and CO emissions cost, and is set as the objective function of the optimization. Second, strength, slump, carbonation, and chloride ingress models are used to evaluate concrete properties. The effect of different climate change scenarios on carbonation and chloride ingress is considered. A genetic algorithm is used to find the optimal mixture considering various constraints. Third, illustrative examples are shown for mixture design of ternary blended concrete. The analysis results show that for ternary blended concrete exposed to an atmospheric environment, a rich mix is necessary to meet the challenge of climate change, and for ternary blended concrete exposed to a marine environment, the impact of climate change on mixture design is marginal.

关键词: ternary blended concrete     climate change     optimal mixture design     carbonation     chloride ingress    

Numerical investigation and optimal design of fiber Bragg grating based wind pressure sensor

Xiangjie WANG, Danhui DAN, Rong XIAO, Xingfei YAN

《结构与土木工程前沿(英文)》 2017年 第11卷 第3期   页码 286-292 doi: 10.1007/s11709-017-0415-9

摘要: A wind pressure sensor based on fiber Bragg grating (FBG) for engineering structure was investigated in this paper. We established a transaction model of wind pressure to strain and proposed a method of temperature compensation. By finite element analysis, the basic parameters of the sensor were optimized with the aim of maximum strain under the basic wind pressure proposed in relative design code in China taking geometrical non-linearity into consideration. The result shows that the wind pressure sensor we proposed is well performed and have good sensing properties, which means it is a technically feasible solution.

关键词: wind pressure measurement     wind pressure sensor     fiber Bragg grating     optimal design    

A PLATFORM TO AID SELECT THE OPTIMAL TOOL TO DESIGN GUIDE RNAS

《农业科学与工程前沿(英文)》   页码 296-305 doi: 10.15302/J-FASE-2022479

摘要:

● Summaries on sgRNAs design.

关键词: CRISPR/Cas     Aid-TG     gene editing     sgRNA design     web server    

Solving multi-objective optimal power flow problem considering wind-STATCOM using differential evolution

Belkacem MAHDAD, K. SRAIRI

《能源前沿(英文)》 2013年 第7卷 第1期   页码 75-89 doi: 10.1007/s11708-012-0222-x

摘要: In this paper, a simple strategy based differential evolution was proposed for solving the problem of multi-objective environmental optimal power flow considering a hybrid model (Wind-Shunt-FACTS). The DE algorithm optimized simultaneously a combined vector control based active power of wind sources and reactive power of multi STATCOM exchanged with the electrical power system to minimize fuel cost and emissions. The proposed strategy was examined and applied to the standard IEEE 30-bus with smooth cost function to solve the problem of security environmental economic dispatch considering multi distributed hybrid model based wind and STATCOM controllers. In addition, the proposed approach was validated on a large practical electrical power system 40 generating units considering valve point effect. Simulation results demonstrate that choosing the installation of multi type of FACTS devices in coordination with many distributed wind sources is a vital research area.

关键词: differential evolution     multi-objective function     optimal power flow     economic dispatch     valve point effect     environment     wind source     STATCOM    

Trajectory planning of mobile robots using indirect solution of optimal control method in generalized

M. NAZEMIZADEH, H. N. RAHIMI, K. AMINI KHOIY

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 23-28 doi: 10.1007/s11465-012-0304-9

摘要:

This paper presents an optimal control strategy for optimal trajectory planning of mobile robots by considering nonlinear dynamic model and nonholonomic constraints of the system. The nonholonomic constraints of the system are introduced by a nonintegrable set of differential equations which represent kinematic restriction on the motion. The Lagrange’s principle is employed to derive the nonlinear equations of the system. Then, the optimal path planning of the mobile robot is formulated as an optimal control problem. To set up the problem, the nonlinear equations of the system are assumed as constraints, and a minimum energy objective function is defined. To solve the problem, an indirect solution of the optimal control method is employed, and conditions of the optimality derived as a set of coupled nonlinear differential equations. The optimality equations are solved numerically, and various simulations are performed for a nonholonomic mobile robot to illustrate effectiveness of the proposed method.

关键词: mobile robot     trajectory planning     nonlinear dynamic     optimal control    

Structural optimal design of a swing vane compressor

Junjie MA,Xiang CHEN,Zongchang QU

《能源前沿(英文)》 2019年 第13卷 第4期   页码 764-769 doi: 10.1007/s11708-016-0449-z

摘要: In this paper, a novel swing vane rotary compressor (SVC) was introduced, which had significant advantages—simple mechanism, reduced frictional loss, reliable operation, and a comparatively higher compression ratio. Based on the swing vane compressor geometry model, thermodynamic model and kinetic model, the mathematical model of optimum design was established, and further theoretical and experimental studies were conducted. The length of the cylinder, radius of the rotor and cylinder were defined as design variables and the reciprocal of EER as objective function. The complex optimization method was adopted to study the structure of the swing vane compressor. The theoretical model could provide an effective method for predicting compressor performance, which would also contribute to structural optimization of the SVC. The study shows that the friction loss of the compressor are greatly reduced by optimized design in a given initial value, and the EER increased by 8.55%.

关键词: swing vane compressor     simulation     optimization design    

Linear quadratic optimal controller for cable-driven parallel robots

Saeed ABDOLSHAH,Erfan SHOJAEI BARJUEI

《机械工程前沿(英文)》 2015年 第10卷 第4期   页码 344-351 doi: 10.1007/s11465-015-0364-8

摘要:

In recent years, various cable-driven parallel robots have been investigated for their advantages, such as low structural weight, high acceleration, and large workspace, over serial and conventional parallel systems. However, the use of cables lowers the stiffness of these robots, which in turn may decrease motion accuracy. A linear quadratic (LQ) optimal controller can provide all the states of a system for the feedback, such as position and velocity. Thus, the application of such an optimal controller in cable-driven parallel robots can result in more efficient and accurate motion compared to the performance of classical controllers such as the proportional-integral-derivative controller. This paper presents an approach to apply the LQ optimal controller on cable-driven parallel robots. To employ the optimal control theory, the static and dynamic modeling of a 3-DOF planar cable-driven parallel robot (Feriba-3) is developed. The synthesis of the LQ optimal control is described, and the significant experimental results are presented and discussed.

关键词: accuracy     cable-driven parallel robot     linear quadratic optimal control    

Multi-objective optimal allocation strategy for the energy internet in Huangpu District, Guangzhou, China

Pei LI, Guotian CAI, Yuntao ZHANG, Shangjun KE, Peng WANG, Liping GAO

《能源前沿(英文)》 2020年 第14卷 第2期   页码 241-253 doi: 10.1007/s11708-020-0660-9

摘要: To improve the overall efficiency of the energy system, the basic structure for the energy internet of coordination and optimization of “generation-grid-load-storage” of Huangpu District, Guangzhou, China is designed, while the arrangement for the output of centralized and distributed energy module and energy storage are proposed. Taking economic benefit maximization, environmental benefit maximization and energy efficiency maximization as sub-objectives, the mathematical model of multi-objective optimal allocation and operation strategy of the energy internet is established considering supply-demand balance constraints, equipment characteristic constraints, operation mode constraints, and energy conditions constraints. The calculation results show that without considering the outsourced electricity, the balanced strategy, the economic development strategy, the environmental protection strategy, and the energy efficiency strategy are obtained by calculation, which are all superior to the traditional energy supply strategy. Moreover, considering the outsourced electricity, the proportion of outsourced electricity to total electricity is 19.8%, which is the system optimization of the energy internet under certain power demand. Compared with other strategies without outsourced electricity, the outsourced electricity strategy can have a certain emission reduction effect, but at the same time reduce the economic benefit. Furthermore, the huge difference in demand for thermal and cooling load between industrial and commercial areas results in the installed capacity of gas distributed energy stations in industrial areas being nearly twice as large as that in commercial areas. The distributed photovoltaic power generation is allocated according to the proportion of the installed roof areas of photovoltaic power generation system in residential, industrial, and commercial areas.

关键词: generation-grid-load-storage     energy internet     economy-environment-energy efficiency     multi-objective optimal allocation     mathematical model    

标题 作者 时间 类型 操作

Life-cycle cost analysis of optimal timing of pavement preservation

Zilong WANG,Hao WANG

期刊论文

Optimal Timing and Recycling Operation Mode for Electro-Mechanical Products Active Remanufacturing

Wang Gao,Tao Li,Shi-tong Peng,Liang Wang,Hong-chao Zhang

期刊论文

Effects of fuel combination and IVO timing on combustion and emissions of a dual-fuel HCCI combustion

Xin LIANG, Jianyong ZHANG, Zhongzhao LI, Jiabo ZHANG, Zhen HUANG, Dong HAN

期刊论文

Effect of ignition timing and hydrogen fraction on combustion and emission characteristics of natural

WANG Jinhua, HUANG Zuohua, LIU Bing, ZENG Ke, YU Jinrong, JIANG Deming

期刊论文

Multi-stage dual replica bit-line delay technique for process-variation-robust timing of lowvoltageSRAMsense

Shou-biao TAN,Wen-juan LU,Chun-yu PENG,Zheng-ping LI,You-wu TAO,Jun-ning CHEN

期刊论文

Smart product design for automotive systems

A. Galip ULSOY

期刊论文

A global synthesis of the effectiveness and ecological impacts of management interventions for species

期刊论文

Impacts of climate change on optimal mixture design of blended concrete considering carbonation and chloride

Xiao-Yong WANG

期刊论文

Numerical investigation and optimal design of fiber Bragg grating based wind pressure sensor

Xiangjie WANG, Danhui DAN, Rong XIAO, Xingfei YAN

期刊论文

A PLATFORM TO AID SELECT THE OPTIMAL TOOL TO DESIGN GUIDE RNAS

期刊论文

Solving multi-objective optimal power flow problem considering wind-STATCOM using differential evolution

Belkacem MAHDAD, K. SRAIRI

期刊论文

Trajectory planning of mobile robots using indirect solution of optimal control method in generalized

M. NAZEMIZADEH, H. N. RAHIMI, K. AMINI KHOIY

期刊论文

Structural optimal design of a swing vane compressor

Junjie MA,Xiang CHEN,Zongchang QU

期刊论文

Linear quadratic optimal controller for cable-driven parallel robots

Saeed ABDOLSHAH,Erfan SHOJAEI BARJUEI

期刊论文

Multi-objective optimal allocation strategy for the energy internet in Huangpu District, Guangzhou, China

Pei LI, Guotian CAI, Yuntao ZHANG, Shangjun KE, Peng WANG, Liping GAO

期刊论文