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优化 2

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Study of simultaneous saccharification and fermentation for steam exploded wheat straw to ethanol

LUO Peng, YANG Chuanmin, LIU Zhong, WANG Gaosheng

《化学科学与工程前沿（英文）》 2008年第2卷第4期页码 447-451 doi: 10.1007/s11705-008-0069-1

摘要： Although simultaneous saccharification and fermentation (SSF) has been investigated extensively, the optimum condition for SSF of wheat straw has not yet been determined. Dilute sulfuric acid impregnated and steam explosion pretreated wheat straw was used as a substrate for the production of ethanol by SSF through orthogonal experiment design in this study. Cellulase mixture (Celluclast 1.5 l and -glucosidase Novozym 188) were adopted in combination with the yeast AS2.1. The effects of reaction temperature, substrate concentration, initial fermentation liquid pH value and enzyme loading were evaluated and the SSF conditions were optimized. The ranking, from high to low, of influential extent of the SSF affecting factors to ethanol concentration and yield was substrate concentration, enzyme loading, initial fermentation liquid pH value and reaction temperature, respectively. The optimal SSF conditions were: reaction temperature, 35°C; substrate concentration, 100 g·L; initial fermentation liquid pH, 5.0; enzyme loading, 30 FPU·g. Under these conditions, the ethanol concentration increased with reaction time, and after 72 h, ethanol was obtained in 65.8% yield with a concentration of 22.7 g·L.

关键词： optimal SSF substrate concentration optimum condition enzyme loading ethanol concentration

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Direct ethanol production from rice straw by coculture with two high-performing fungi

Maki TAKANO, Kazuhiro HOSHINO

《化学科学与工程前沿（英文）》 2012年第6卷第2期页码 139-145 doi: 10.1007/s11705-012-1281-6

摘要： To develop efficient and economical direct ethanol production from fine rice straw crashed mechanically, two high-performing fungi, which can secret hyperactive cellulases and/or ferment effectively various sugars, were selected from some strains belong to preserved in our laboratory. The simultaneous saccharification and fermentation (SSF) by coculture with these fungi was investigated. The screening of high-performing fungi resulted in the selection of NBRC 4572 as an ethanol-producing fungus and NBRC 5398 as a cellulase-secreting fungus. The strain 4572 produced ethanol aerobically from glucose and xylose in high yields of 0.420 g/g at 36 h and 0.478 g/g at 60 h, respectively, but secreted fairly low cellulases. On the other hand, the strain 5398 also produced ethanol from glucose in yield of 0.340 g/g though it had a little growth in xylose culture. However, it secreted hyperactive cellulases that are essential for hydrolysis of rice straw in culture and the maximum activities of endo-β-glucanase and β-glucosidase were 2.11 U/L and 1.47 U/L, respectively. In SSF of rice straw by coculture with two fungi selected, the ethanol production reached 1.28 g/L after 96 h when the inoculation ratio of the strain 5398 to the strain 4572 was 9.

关键词： Mucor circinelloides ethanol production cellulase secretion SSF coculture rice straw

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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

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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

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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

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Simultaneous saccharification and fermentation of wheat bran flour into ethanol using coculture of amylotic

K. Manikandan, T. Viruthagiri

《化学科学与工程前沿（英文）》 2009年第3卷第3期页码 240-249 doi: 10.1007/s11705-009-0205-6

摘要： Studies on simultaneous saccharification and fermentation (SSF) of wheat bran flour, a grain milling residue as the substrate using coculture method were carried out with strains of starch digesting and nonstarch digesting and sugar fermenting in batch fermentation. Experiments based on central composite design (CCD) were conducted to maximize the glucose yield and to study the effects of substrate concentration, pH, temperature, and enzyme concentration on percentage conversion of wheat bran flour starch to glucose by treatment with fungal α-amylase and the above parameters were optimized using response surface methodology (RSM). The optimum values of substrate concentration, pH, temperature, and enzyme concentration were found to be 200 g/L, 5.5, 65°C and 7.5 IU, respectively, in the starch saccharification step. The effects of pH, temperature and substrate concentration on ethanol concentration, biomass and reducing sugar concentration were also investigated. The optimum temperature and pH were found to be 30°C and 5.5, respectively. The wheat bran flour solution equivalent to 6% ( / ) initial starch concentration gave the highest ethanol concentration of 23.1 g/L after 48 h of fermentation at optimum conditions of pH and temperature. The growth kinetics was modeled using Monod model and Logistic model and product formation kinetics using Leudeking-Piret model. Simultaneous saccharificiation and fermentation of liquefied wheat bran starch to bioethanol was studied using coculture of amylolytic fungus and nonamylolytic sugar fermenting .

关键词： simultaneous saccharification and fermentation (SSF) starch coculture fermentation statistical experimental design bioethanol Monod model

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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

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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

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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

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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

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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

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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

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Fuel optimal control of parallel hybrid electric vehicles

PU Jinhuan, YIN Chenliang, ZHANG Jianwu

《机械工程前沿（英文）》 2008年第3卷第3期页码 337-342 doi: 10.1007/s11465-008-0057-7

摘要： A mathematical model for fuel optimal control and its corresponding dynamic programming (DP) recursive equation were established for an existing parallel hybrid electric vehicle (HEV). Two augmented cost functions for gear shifting and engine stop-starting were designed to limit their frequency. To overcome the problem of numerical DP dimensionality, an algorithm to restrict the exploring region was proposed. The algorithm significantly reduced the computational complexity. The system model was converted into real-time simulation code by using MATLAB/RTW to improve computation efficiency. Comparison between the results of a chassis dynamometer test, simulation, and DP proves that the proposed method can compute the performance limitation of the HEV within an acceptable time period and can be used to evaluate and optimize the control strategy.

关键词： mathematical Comparison computational complexity dimensionality corresponding

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Simulation of the optimal heat rejection pressure for transcritical CO

Junlan YANG, Yitai MA, Minxia LI, Hua TIAN

《能源前沿（英文）》 2010年第4卷第4期页码 522-526 doi: 10.1007/s11708-010-0027-8

摘要： In order to optimize and control transcritical CO refrigeration cycle, a mathematical model was developed to simulate the system performance. The simulation results show that a maximum COP exists at the optimal heat rejection pressure not only for throttle valve cycle but also for expander cycle. Also, the optimal heat rejection pressures of the throttle valve cycle are greater than those of the expander cycle under the same condition. In order to further obtain correlation of the optimal heat rejection pressure for transcritical CO expander cycle, it is necessary to analyze the impact degree of compressor efficiency, expander efficiency, gas cooler outlet temperature and evaporation temperature. Based on the simulation results, the values of the optimal heat rejection pressure for the expander cycle were regressed in terms of gas cooler outlet temperature and evaporation temperature at given compressor efficiency and expander efficiency. Finally, two types of polynomial correlations were obtained. One is cubic form, with an average deviation of less than 0.5% and the other is simplified form, with an average deviation of less than 1%. It is, therefore, convenient to use either correlation to simulate the performance of transcritical CO expander cycle.

关键词： transcritical CO₂ cycle optimal heat rejection pressure simulation expander

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Optimal design of a linkage–cam mechanism-based redundantly actuated parallel manipulator

《机械工程前沿（英文）》 2021年第16卷第3期页码 451-467 doi: 10.1007/s11465-021-0634-6

摘要： A redundantly actuated parallel manipulator (RAPM) with mixed translational and rotational degrees of freedom (DOFs) is challenged for its dimensionally homogeneous Jacobian modeling and optimal design of architecture. In this paper, a means to achieve redundant actuation by adding kinematic constraints is introduced, which reduces the DOFs of the end-effector (EE). A generic dimensionally homogeneous Jacobian is developed for this type of RAPMs, which maps the generalized velocities of three points on the EE to the joint velocities. A new optimization algorithm derived from this dimensionally homogeneous Jacobian is proposed for the optimal design of this type of RAPMs. As an example, this paper presents a spatial RAPM involving linkages and cam mechanisms. This RAPM has 4 DOFs and 6 translational actuations. The linkage lengths and the position of the universal joints of the RAPM are optimized based on the dimensionally homogeneous Jacobian.

关键词： redundant actuation parallel manipulator linkage–cam mechanism Jacobian optimal design