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Reaction kinetics of CaC

Renxing Wang,Zhenyu Liu,Leiming Ji,Xiaojin Guo,Xi Lin,Junfei Wu,Qingya Liu

《化学科学与工程前沿（英文）》 2016年 第10卷 第4期   页码 517-525 doi: 10.1007/s11705-016-1585-z

摘要： The production of CaC from coke/lime powders and compressed powder pellets are low cost and fast processes. A number of studies have reported the reaction kinetics of these reactions but they are still not well understood and the proposed kinetic models are not comparable due to differences in the reaction conditions. Therefore the reaction behavior of CaO/C powders (0.074 mm) and cubes (5 mm × 5 mm × (4.6–5.1) mm) compressed from a mixture of powders have been studied using thermal gravimetric analysis (TGA) at 1700– 1850 °C. Kinetic models were obtained from the TGA data using isoconversional and model-fitting methods. The reaction rates for the compressed feeds were lower than those for the powder feeds. This is due to the reduced surface area of the compressed samples which inhibits heat transfer from the surrounding environment (or the heating source) to the sample. The compression pressure had little influence on the reaction rate. The reaction kinetics of both the powder and the compressed feeds can be described by the contracting volume model ( ) = 3(1− ) , where is the conversion rate of reactant. The apparent activation energy and pre-exponential factor of the powder feed were estimated to 346–354 kJ?mol and 5.9 × 10 min , respectively, whereas those of the compressed feed were 305–327 kJ?mol and 3.6 × 10 min , respectively.

关键词： calcium carbide     kinetic model     activation energy     pre-exponential factor    

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Quantitatively assessing the pre-grouting effect on the stability of tunnels excavated in fault

Xiao YAN, Zizheng SUN, Shucai LI, Rentai LIU, Qingsong ZHANG, Yiming ZHANG

《结构与土木工程前沿（英文）》 2019年 第13卷 第6期   页码 1393-1404 doi: 10.1007/s11709-019-0563-1

摘要： Pre-grouting is a popular ground treatment strategy utilized to enhance the strength and stability of strata during the excavation of a tunnel through a fault zone. Two important questions need to be answered during such an excavation. First, how should the grouting size be determined? Second, when should excavation begin after grouting? These two questions are conventionally addressed through empirical experience and standard criteria because a reliable quantitative approach, which would be preferable, has not yet been developed. To address these questions, we apply a recently proposed numerical approach known as discontinuity layout optimization, an efficient node-based upper bound limit analysis method. A case study is provided utilizing a tunnel located in a stratum characterized by complicated geological conditions, including soft soil and a fault zone. The factor of safety is used to quantitatively assess the stability of the tunnel section. The influences of the grouted zone thickness and the time-dependent material properties of the grouted zone on the stability of the tunnel section are evaluated, thereby assisting designers by quantitatively assessing the effects of pre-grouting.

关键词： pre-grouting     stability analysis     factor of safety     discontinuity layout optimization    

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General closed-form inverse kinematics for arbitrary three-joint subproblems based on the product of exponential

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0681-7

摘要： The inverse kinematics problems of robots are usually decomposed into several Paden–Kahan subproblems based on the product of exponential model. However, the simple combination of subproblems cannot solve all the inverse kinematics problems, and there is no common approach to solve arbitrary three-joint subproblems in an arbitrary postural relationship. The novel algebraic geometric (NAG) methods that obtain the general closed-form inverse kinematics for all types of three-joint subproblems are presented in this paper. The geometric and algebraic constraints are used as the conditions precedent to solve the inverse kinematics of three-joint subproblems. The NAG methods can be applied in the inverse kinematics of three-joint subproblems in an arbitrary postural relationship. The inverse kinematics simulations of all three-joint subproblems are implemented, and simulation results indicating that the inverse solutions are consistent with the given joint angles validate the general closed-form inverse kinematics. Huaque III minimally invasive surgical robot is used as the experimental platform for the simulation, and a master–slave tracking experiment is conducted to verify the NAG methods. The simulation result shows the inverse solutions and six sets given joint angles are consistent. Additionally, the mean and maximum of the master–slave tracking experiment for the closed-form solution are 0.1486 and 0.4777 mm, respectively, while the mean and maximum of the master–slave tracking experiment for the compensation method are 0.3188 and 0.6394 mm, respectively. The experiments results demonstrate that the closed-form solution is superior to the compensation method. The results verify the proposed general closed-form inverse kinematics based on the NAG methods.

关键词： inverse kinematics     Paden–Kahan subproblems     three-joint subproblems     product of exponential     closed-form solution    

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Ultrasonic linear motor using the L-B mode Langevin transducer with an exponential horn

SHI Shengjun, CHEN Weishan, LIU Junkao, ZHAO Xuetao

《机械工程前沿（英文）》 2008年 第3卷 第2期   页码 212-217 doi: 10.1007/s11465-008-0026-1

摘要： An ultrasonic linear motor is proposed and fabricated by using the longitudinal and bending vibration double mode bolt-clamped Langevin type transducer to meet high power and speed requirements in the aerospace and semiconductor ind

关键词： longitudinal     vibration     bolt-clamped     semiconductor     ultrasonic    

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应用指数平滑技术预测边坡位移

沈良峰

《中国工程科学》 2007年 第9卷 第6期   页码 94-97

摘要：

应用趋势型指数平滑模型根据其观测值的数据特点（具线性趋势），选取趋势型二次指数平滑的线性 预测公式和相应at，bt的计算公式及合适的平滑系数值进行计算，预测了某市滑坡区５号监测点的位移量。预 测结果表明，该方法应用于斜坡变形位移的预测，可使预测值与实际位移值之间的误差很小。

关键词： 指数平滑     预测边坡位移     自适应过滤    

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指数多项式均匀样条模型

赵颜利,平萍,刘凤玉

《中国工程科学》 2008年 第10卷 第7期   页码 147-152

摘要：

给出了k（ k ≥ ３） 阶指数多项式的均匀样条模型。该类模型具有很多与B 样条模型相同的性质，并 且增加了一个可调节的形状参数。由该模型构造的曲线，通过改变形状参数的取值，可以调整曲线接近其控 制多边形的程度。应用于CAD/CAM领域，可作为几何造型的一种新的有效模型。

关键词： 指数多项式样条函数     B样条函数     形状参数    

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Minimization of total energy consumption in an m-machine flow shop with an exponential time-dependent

Lingxuan LIU, Zhongshun SHI, Leyuan SHI

《工程管理前沿（英文）》 2018年 第5卷 第4期   页码 487-498 doi: 10.15302/J-FEM-2018042

摘要：

This study investigates an energy-aware flow shop scheduling problem with a time-dependent learning effect. The relationship between the traditional and the proposed scheduling problem is shown and objective is to determine a job sequence in which the total energy consumption is minimized. To provide an efficient solution framework, composite lower bounds are proposed to be used in a solution approach with the name of Bounds-based Nested Partition (BBNP). A worst-case analysis on shortest process time heuristic is conducted for theoretical measurement. Computational experiments are performed on randomly generated test instances to evaluate the proposed algorithms. Results show that BBNP has better performance than conventional heuristics and provides considerable computational advantage.

关键词： flow shop     energy-aware scheduling     learning effect     nested partition     worst-case error bound    

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Nonlinear analysis of pre-tensioned glass wall facade by stability function with initial imperfection

Siu-Lai CHAN, Yaopeng LIU, Andy LEE,

《结构与土木工程前沿（英文）》 2010年 第4卷 第3期   页码 376-382 doi: 10.1007/s11709-010-0086-2

摘要： Pre-tensioned high strength trusses using alloy steel bar are widely used as glass wall supporting systems because of the high degree of transparency. The breakage of glass panes in this type of system occurs occasionally, likely to be due to error in design and analysis in addition to other factors like glass impurity and stress concentration around opening in a spider system. Most design does not consider the flexibility of supports from finite stiffness of supporting steel or reinforced concrete beams. The resistance of lateral wind pressure of the system makes use of high tension force coupled with the large deflection effect, both of which are affected by many parameters not generally considered in conventional structures. In the design, one must therefore give a careful consideration on various effects, such as support settlement due to live loads and material creep, temperature change, pre-tension force, and wind pressure. It is not uncommon to see many similar glass wall systems fail in the wind load test chambers under a design wind speed. This paper presents a rigorous analysis and design of this type of structural systems used in a project in Hong Kong, China. The stability function with initial curvature is used in place of the cubic function, which is only accurate for linear analysis. The considerations and analysis techniques are believed to be of value to engineers involved in the design of the structural systems behaving nonlinearly.

关键词： tension system     glass wall     nonlinear analysis     pre-tensioning     second-order analysis    

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A pre-compensation method of the systematic contouring error for repetitive command paths

D. L. ZHANG,Y. H. CHEN,Y. P. CHEN

《机械工程前沿（英文）》 2015年 第10卷 第4期   页码 367-372 doi: 10.1007/s11465-015-0367-5

摘要：

For a repetitive command path, pre-compensating the contouring error by modifying the command path is practical. To obtain the pre-compensation value with better accuracy, this paper proposes the use of a back propagation neural network to extract the function of systematic contouring errors. Furthermore, by using the extracted function, the contouring error can be easily pre-compensated. The experiment results verify that the proposed compensation method can effectively reduce contouring errors.

关键词： contouring error     pre-compensation     motion control system     back propagation (BP) neural network    

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Experimental and parametrical investigation of pre-stressed ultrahigh-performance fiber-reinforced concrete

《结构与土木工程前沿（英文）》 2023年 第17卷 第3期   页码 411-428 doi: 10.1007/s11709-023-0928-3

摘要： In this study, ultrahigh-performance fiber-reinforced concrete (UHPFRC) used in a type B70 concrete sleeper is investigated experimentally and parametrically. The main parameters investigated are the steel fiber volume fractions (0%, 0.5%, 1%, and 1.5%). Under European standards, 35 UHPFRC sleepers are subjected to static bending tests at the center and rail seat sections, and the screw on the fastening system is pulled out. The first cracking load, failure load, failure mode, crack propagation, load–deflection curve, load–crack width, and failure load from these tests are measured and compared with those of a control sleeper manufactured using normal concrete C50. The accuracy of the parametric study is verified experimentally. Subsequently, the results of the study are applied to UHPFRC sleepers with different concrete volumes to investigate the effects of the properties of UHPFRC on their performance. Experimental and parametric study results show that the behavior of UHPFRC sleepers improves significantly when the amount of steel fiber in the mix is increased. Sleepers manufactured using UHPFRC with a steel fiber volume fraction of 1% and a concrete volume less than 25% that of standard sleeper B70 can be used under the same loads and requirements, which contributes positively to the cost and surrounding environment.

关键词： pre-stressed concrete sleeper     ultrahigh performance fiber-reinforced concrete     pull-out test     static bending test     steel fiber     aspect ratio     volume fraction    

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Investigation into viability of using two-stage (pre-placed aggregate) concrete in Irish setting

John O’MALLEY, Hakim S. ABDELGADER,

《结构与土木工程前沿（英文）》 2010年 第4卷 第1期   页码 127-132 doi: 10.1007/s11709-010-0007-4

摘要： Two-stage (pre-placed aggregate) concrete (TSC) consists of coarse aggregate, which is first deposited into the formwork, and grout, which is later pumped into the formwork from the bottom up to bind the stone together into a monolith. During the course of this study the formation of grout for two stage concrete was investigated using readily available 5 mm sand mixed in a slow speed paddle mixer.  Silica fume and a superplasticizer were used in the mix to see if the necessary stability and fluidity could be achieved without the use of a specialized plant, essentially to see if TSC could be produced on a small scale using native Irish aggregates. A much higher degree of sedimentation was recorded during testing than was expected. As a result, the use of 5 mm sand and a slow speed mixer in combination were found to be not conducive to the successful production of TSC grout, without further research and testing.

关键词： grout     pre-placed     concrete     two-stage concrete (TSC)    

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Optimization of denitrifying phosphorus removal in a pre-denitrification anaerobic/anoxic/post-aeration+ nitrification sequence batch reactor (pre-A

Weihua Zhao, Meixiang Wang, Jianwei Li, Yu Huang, Baikun Li, Cong Pan, Xiyao Li, Yongzhen Peng

《环境科学与工程前沿（英文）》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1084-1

摘要：

A novel two sludge pre-A2NSBR system was developed.

Advanced N and P removal was optimized to treat real domestic wastewater.

Nitrifiers and PAOs were enriched with 19.41% and 26.48%, respectively.

Acetate was demonstrated as the high-quality carbon source type.

关键词： Denitrifying phosphorus removal     C/N ratio     Nitrate recycling     Carbon source type     Biological nutrient removal     Pre-A2NSBR system    

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Evaluation of the static and dynamic structural performance of segmental pre-stressed concrete box girder

Ali Fadhil NASER, Zonglin WANG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 164-177 doi: 10.1007/s11709-013-0196-8

摘要： The objectives of this study are to explain the repairing and strengthening methods which are used to improve the structural performance of the bridge structure, to analyze the static and dynamic responses after strengthening, and to evaluate the performance of the bridge structure after repairing and strengthening. The methods of repairing and strengthening include reconstruction the deck of the bridge by casting 10 cm layer of concrete, strengthening the web and bottom floor of box girders of middle spans and side spans by sticking the steel plates, strengthening the whole bridge structure by using external pre-stressing tendons, and treatment the cracks. The results of theoretical analysis show that the values of tensile stress and vertical deflection are decreased and the compressive stress is increased after strengthening. There are not tensile stresses are appeared in the sections of the bridge structure. The modal analysis results show that the value of natural frequency is equal to 2.09 Hz which is more than the values before strengthening which is equal to 1.64 Hz, indicating that the stiffness of the bridge structure is improved and the strengthening process is effective to improve the cracks resistance and bearing capacity of the bridge structure.

关键词： structural performance     steel plates     external pre-stressing     cracks     grouting method     static    

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Techno-economic comparison of three technologies for pre-combustion CO

Simon Roussanaly, Monika Vitvarova, Rahul Anantharaman, David Berstad, Brede Hagen, Jana Jakobsen, Vaclav Novotny, Geir Skaugen

《化学科学与工程前沿（英文）》 2020年 第14卷 第3期   页码 436-452 doi: 10.1007/s11705-019-1870-8

摘要： This paper compares the techno-economic performances of three technologies for CO capture from a lignite-based IGCC power plant located in the Czech Republic: (1) Physical absorption with a Rectisol-based process; (2) Polymeric CO -selective membrane-based capture; (3) Low-temperature capture. The evaluations show that the IGCC plant with CO capture leads to costs of electricity between 91 and 120 €·MWh , depending on the capture technology employed, compared to 65 €·MWh for the power plant without capture. This results in CO avoidance costs ranging from 42 to 84 €· , mainly linked to the losses in net power output. From both energy and cost points of view, the low-temperature and Rectisol based CO capture processes are the most efficient capture technologies. Furthermore, partial CO capture appears as a good mean to ensure early implementation due to the limited increase in CO avoidance cost when considering partial capture. To go beyond the two specific CO -selective membranes considered, a cost/membrane property map for CO -selective membranes was developed. This map emphasise the need to develop high performance membrane to compete with solvent technology. Finally, the cost of the whole CCS chain was estimated at 54 €· once pipeline transport and storage are taken into consideration.

关键词： carbon capture and storage (CCS)     techno-economic comparison     pre-combustion capture     physical solvent     low-temperature capture    

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Hybrid flexural components: Testing pre-stressed steel and GFRP bars together as reinforcement for flexural

Mohammed FARUQI, Oved I. MATA, Francisco AGUINIGA

《结构与土木工程前沿（英文）》 2018年 第12卷 第3期   页码 352-360 doi: 10.1007/s11709-017-0453-3

摘要：

Concrete members historically have used either pre-stressed steel or steel bars. In recent years there has been an increased interest in the use of fiber reinforced polymer (FRP) materials. However, the flexure behavior of a hybrid system reinforced by the combination of pre-stressed steel and glass fiber reinforced (GFRP) is still relatively unknown. The purpose of this work is to study this. Two slabs of 100 and 150-millimeter thickness, with a span of 2.1 m reinforced with both pre-stressing steel and GFRP were constructed and tested to failure using ACI 318-11 and ACI 440.1R-15. The concrete had strength of 31 MPa and the slabs were respectively reinforced with 5#4 bars and 3#5 bars. Each slab had 37.41 mm2 prestressing wire with a failure stress of 1722.5 MPa. The experimental flexural strength and deflection of slabs were compared with their respective sizes theoretical slabs. The theoretical slabs were either reinforced with pre-stressed steel or GFRP rebars, or a hybrid system. It was found that the hybrid system produces better results.

关键词： Partial pre-stressing     composite structures     GFRP bars    

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标题 作者 时间 类型 操作

Reaction kinetics of CaC

Renxing Wang,Zhenyu Liu,Leiming Ji,Xiaojin Guo,Xi Lin,Junfei Wu,Qingya Liu

期刊论文

Quantitatively assessing the pre-grouting effect on the stability of tunnels excavated in fault

Xiao YAN, Zizheng SUN, Shucai LI, Rentai LIU, Qingsong ZHANG, Yiming ZHANG

期刊论文

General closed-form inverse kinematics for arbitrary three-joint subproblems based on the product of exponential

期刊论文

Ultrasonic linear motor using the L-B mode Langevin transducer with an exponential horn

SHI Shengjun, CHEN Weishan, LIU Junkao, ZHAO Xuetao

期刊论文

应用指数平滑技术预测边坡位移

沈良峰

期刊论文

指数多项式均匀样条模型

赵颜利,平萍,刘凤玉

期刊论文

Minimization of total energy consumption in an m-machine flow shop with an exponential time-dependent

Lingxuan LIU, Zhongshun SHI, Leyuan SHI

期刊论文

Nonlinear analysis of pre-tensioned glass wall facade by stability function with initial imperfection

Siu-Lai CHAN, Yaopeng LIU, Andy LEE,

期刊论文

A pre-compensation method of the systematic contouring error for repetitive command paths

D. L. ZHANG,Y. H. CHEN,Y. P. CHEN

期刊论文

Experimental and parametrical investigation of pre-stressed ultrahigh-performance fiber-reinforced concrete

期刊论文

Investigation into viability of using two-stage (pre-placed aggregate) concrete in Irish setting

John O’MALLEY, Hakim S. ABDELGADER,

期刊论文

Optimization of denitrifying phosphorus removal in a pre-denitrification anaerobic/anoxic/post-aeration+ nitrification sequence batch reactor (pre-A

Weihua Zhao, Meixiang Wang, Jianwei Li, Yu Huang, Baikun Li, Cong Pan, Xiyao Li, Yongzhen Peng

期刊论文

Evaluation of the static and dynamic structural performance of segmental pre-stressed concrete box girder

Ali Fadhil NASER, Zonglin WANG

期刊论文

Techno-economic comparison of three technologies for pre-combustion CO

Simon Roussanaly, Monika Vitvarova, Rahul Anantharaman, David Berstad, Brede Hagen, Jana Jakobsen, Vaclav Novotny, Geir Skaugen

期刊论文

Hybrid flexural components: Testing pre-stressed steel and GFRP bars together as reinforcement for flexural

Mohammed FARUQI, Oved I. MATA, Francisco AGUINIGA

期刊论文