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A methodology of implementing target mixing ratio for asphalt mixture

Yucheng HUANG, Lun JI, Rui WEN, Ming ZHANG

《结构与土木工程前沿(英文)》 2017年 第11卷 第3期   页码 308-314 doi: 10.1007/s11709-017-0405-y

摘要: In order to implement the objective mix design of hot mix asphalt adequately during the construction process, the significance of objective mixing ratio was elaborated, and the variability of materials and its control method were analyzed. An engineering example is used to illustrate the debugging process of asphalt mixture batching & mixing plant and the dynamic quality management methods. The results show that the set of methods can not only implement the objective mixing ratio of hot mix asphalt adequately, but also control production during the construction process effectively.

关键词: asphalt mixture     target mixing ratio     mix design implementation     batching & mixing plant debugging    

Characterization of micro-mixing in a novel impinging streams reactor

Hui HU, Zhiming CHEN, Zhen JIAO

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 58-64 doi: 10.1007/s11705-009-0106-8

摘要: This paper presents an experimental investigation of a novel impinging stream reactor (ISR) with the aim of high mixing intensity. The integral mixing quality in the reactor was measured with the iodide-iodate reaction and showed excellent mixing performance. The impact of the operating parameters, such as fluxes, circulation and inter-nozzle distances, was investigated in terms of segregation index. The results showed that the increase of flux, the decrease of inter-nozzle distance and a suitable circulation can improve the micro-mixing efficiency. Based on turbulence theory, it was estimated that the characteristic micro-mixing time was 0.002—0.02 s, which was much shorter than that in the stirred tank reactor. The micro-mixing time was related to the segregation index, which was in good agreement with those in the literature.

关键词: micro-mixing     impinging streams reactor     turbulent mixing     mass transfer    

Chemical probe systems for assessing liquid–liquid mixing efficiencies of reactors

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1323-1335 doi: 10.1007/s11705-022-2275-7

摘要: Liquid–liquid mixing, including homogeneous and heterogeneous mixing, widely exists in the chemical industry. How to quantitatively characterize the mixing performance is important for reactor assessment and development. As a convenient and direct method for mixing characterization, the chemical probe method uses some special test reactions to characterize the mixing results. Here, the working principle and selection requirements of this method are introduced, and some common chemical probe systems for homogeneous and heterogeneous mixing processes are reviewed. The characteristics and applications of these systems are illustrated. Finally, the development of the new system is proposed.

关键词: mixing     chemical probe     liquid–liquid     heterogeneous    

Combined static mixers for high viscous fluids mixing

Zhenhao XI, Weizhen SUN, Ling ZHAO, Zhaoyan LIU

《化学科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 93-96 doi: 10.1007/s11705-009-0112-x

摘要: A new static mixer Cross-over-Disc has been invented to strip off the boundary layer and to make strong radial mixing. The pressure drop of Cross-over-Disc is 12—26 times as large as that of empty pipe with equivalent diameter and length. The mixing performance of Cross-over-Disc with 14 elements has been investigated in the viscosity range of 190—250 Pa?s by decoloration method, and the gray analysis of images shows that mixing inhomogeneity is about 7.5% and 9.4% for the mixing ratio of 5∶1 and 10∶1, respectively. Furthermore, mixing inhomogeneity for a combination of static mixing elements (four from Cross-over-Disc and three pairs from Sulzer-type) can be decreased to 2.1%—3.1% within a reasonable range of pressure drop.

关键词: static mixer     Cross-over-Disc     pressure drop     mixing performance     high viscous fluid    

Reliability-based settlement analysis of embankments over soft soils reinforced with T-shaped deep cement mixing

Chana PHUTTHANANON; Pornkasem JONGPRADIST; Daniel DIAS; Xiangfeng GUO; Pitthaya JAMSAWANG; Julien BAROTH

《结构与土木工程前沿(英文)》 2022年 第16卷 第5期   页码 638-656 doi: 10.1007/s11709-022-0825-1

摘要: This paper presents a reliability-based settlement analysis of T-shaped deep cement mixing (TDM) pile-supported embankments over soft soils. The uncertainties of the mechanical properties of the in-situ soil, pile, and embankment, and the effect of the pile shape are considered simultaneously. The analyses are performed using Monte Carlo Simulations in combination with an adaptive Kriging (using adaptive sampling algorithm). Individual and system failure probabilities, in terms of the differential and maximum settlements (serviceability limit state (SLS) requirements), are considered. The reliability results for the embankments supported by TDM piles, with various shapes, are compared and discussed together with the results for conventional deep cement mixing pile-supported embankments with equivalent pile volumes. The influences of the inherent variabilities in the material properties (mean and coefficient of variation values) on the reliability of the piled embankments, are also investigated. This study shows that large TDM piles, particularly those with a shape factor of greater than 3, can enhance the reliability of the embankment in terms of SLS requirements, and even avoid unacceptable reliability levels caused by variability in the material properties.

关键词: T-shaped deep cement mixing piles     piled embankments     settlement     reliability analysis     soil uncertainties    

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

《环境科学与工程前沿(英文)》 2016年 第10卷 第5期 doi: 10.1007/s11783-016-0861-y

摘要: Four types of S-rich particles are identified by SEM/FESEM-EDX With on-line observation, characteristics of S-rich particles are discovered Intensities of formation of S-rich particles are seasonally different Direct individual analysis using Scanning Electron Microscopy combined with online observation was conducted to examine the S-rich particles in PM of two typical polluted haze episodes in summer and winter from 2014 to 2015 in Beijing. Four major types of S-rich particles, including secondary CaSO particles (mainly observed in summer), S-rich mineral particles (SRM), S-rich water droplets (SRW) and (C, O, S)-rich particles (COS) were identified. We found the different typical morphologies and element distributions of S-rich particles and considered that (C, O, S)-rich particles had two major mixing states in different seasons. On the basis of the S-rich particles’ relative abundances, S concentrations and their relationships with PM as well as the seasonal comparison, we revealed that the S-participated formation degrees of SRM and SRW would enhance with increasing PM concentration. Moreover, C-rich matter and sulfate had seasonally different but significant impacts on the formation of COS.

关键词: S-rich particles     Morphology     Element distribution     Mixing state    

Dispersion of a novel phenolic rigid organic filler in isotactic polypropylene matrix by solution-mixingand melt-mixing

Dongming QI, Xiaoli ZHAO, Zhijie CHEN, Peng HUANG, Jun CAO

《化学科学与工程前沿(英文)》 2012年 第6卷 第4期   页码 395-402 doi: 10.1007/s11705-012-1269-2

摘要: A novel phenolic rigid organic filler (named KD) with a high melting point was dispersed in an isotactic polypropylene (iPP) matrix by solution-mixing and/or melt-mixing. A series of KD/iPP blends was prepared with or without addition of maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer. Influences of MAPP and mixing methods on the filler dispersion were studied using polaried optical microscope (POM), scanning electron microscope (SEM) and tensile test. The filler particles are always inclined to form large irregular aggregates in the iPP matrix due to their significant differences in polarity and solubility in solvent. However, an iPP/MAPP/KD (PMK) blend containing filler particles with a quasi-spherical shape (~97.8 nm in diameter) and narrow particle size distribution (polydispersity index= 1.076) was successfully prepared by incorporating MAPP to reduce the interfacial tension and surface free energy between the dispersion phase and the continuous phase, and adopting a spray-drying method after solution-mixing to suppress the increase of the size of the dispersed phase during the removal of solvent.

关键词: dispersion     rigid organic filler     isotactic polypropylene     mixing    

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2161-2161 doi: 10.1007/s11705-009-0143-3

摘要: RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

关键词: tee junction     Momentum exchange coefficient     RETRACTED    

Reliability analysis of the control system of large-scale vertical mixing equipment

YANG Mingjin, LI Xiwen, LI Shaoping, YANG Shuzi

《机械工程前沿(英文)》 2008年 第3卷 第2期   页码 133-138 doi: 10.1007/s11465-008-0037-y

摘要: The control system of vertical mixing equipment is a concentrate distributed monitoring system (CDMS). A reliability analysis model was built and its analysis was conducted based on reliability modeling theories such as the graph theory, Markov process, and redundancy theory. Analysis and operational results show that the control system can meet all technical requirements for high energy composite solid propellant manufacturing. The reliability performance of the control system can be considerably improved by adopting a control strategy combined with the hot spared redundancy of the primary system and the cold spared redundancy of the emergent one. The reliability performance of the control system can be also improved by adopting the redundancy strategy or improving the quality of each component and cable of the system.

关键词: composite     redundancy     monitoring     vertical     technical    

ALKALINE PRETREATMENT AND AIR MIXING FOR IMPROVEMENT OF METHANE PRODUCTION FROM ANAEROBIC CO-DIGESTION

《农业科学与工程前沿(英文)》 2023年 第10卷 第3期   页码 424-436 doi: 10.15302/J-FASE-2023506

摘要:

● Integration of alkaline pretreatment and air mixing for co-digestion was validated.

关键词: sodium hydroxide     air injection     cumulative methane yield     kinetic modeling analysis     digestate    

Online single particle analysis of chemical composition and mixing state of crop straw burning particles

Juntao HUO,Xiaohui LU,Xinning WANG,Hong CHEN,Xingnan YE,Song Gao,Deborah S. Gross,Jianmin CHEN,Xin YANG

《环境科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 244-252 doi: 10.1007/s11783-015-0768-z

摘要: Fresh straw burning (SB) particles were generated in the laboratory by the combustion of rice straw and corn straw. The chemical composition and mixing state of the fresh SB particles were investigated by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS). Based on the mass spectral patterns, the SB particles were clustered into four major types: Salt, Organic Carbon (OC), Elemental Carbon (EC), and internally mixed particles of EC and OC (EC-OC). In addition, particles containing ash, polycyclic aromatic hydrocarbons, heavy metals or nicotine were also observed. Physical and chemical changes of the SB particles immediately after the emission were analyzed with highly time-resolved data. During the aging processes, the average particle size increased steadily. Freshly emitted organic compounds were gradually oxidized to more oxygenated compounds in the OC-containing particles. Meanwhile, an important displacement reaction (2KCl+ → K SO + 2Cl ) was observed. The marker ions for SB particles were optimized and applied to identify the SB particles in the ambient atmosphere. The fluctuation of the number fraction of ambient SB particles sorted by ATOFMS agrees well with that of water soluble K measured by an online ion chromatography, demonstrating that the optimized marker ions could be good tracers for SB particles in field measurements.

关键词: crop straw burning particles     mixing state     aging process     ATOFMS     ion markers    

Continuous reaction performances of benzene alkylation with long chain olefins catalyzed by ionic liquid

QIAO Congzhen, LI Chengyue

《化学科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 69-73 doi: 10.1007/s11705-008-0014-3

摘要: Based on a compulsive mixing-reacting-separating-recycling small experimental setup,the continuous reaction performances of benzene alkylation with long chain olefins catalyzed by [BMIM]Cl-AlCl ionic liquid were investigated. Three different situations including normal continuous operation mode (reagent materials), sidetrack feeding from different axial positions along the static mixing reactor (reagent materials) and normal continuous alkylation using industrial paraffin and olefins materials were examined. Even under the relatively hypecritical reaction conditions, the single pass conversion of pure 1-dodecene could reach to nearly 100.0%, and the selectivity of 2-phenyl isomer was higher than 37.7%. Although the positions along the reactor for sidetrack feeding were different, the 100.0% single pass conversion of 1-dodecene was also attained before the outlet of the reactor. The refined industrial olefins as raw material could meet with the requirements of continuous alkylation. The influences of impurities such as di-olefins and non-benzene aromatics on the catalytic activity and stability should be studied further.

关键词: stability     different     hypecritical     compulsive mixing-reacting-separating-recycling     non-benzene    

A method for predicting consolidation settlements of floating column improved clayey subsoil

Jinchun CHAI, Supasit PONGSIVASATHIT,

《结构与土木工程前沿(英文)》 2010年 第4卷 第2期   页码 241-251 doi: 10.1007/s11709-010-0024-3

摘要: A method of predicting the consolidation settlement-time curve of floating soil-cement column on improved soft clayey subsoil has been proposed. The degree of the consolidation (()) of the system is calculated by the double soil-layer consolidation theory, and the methods for evaluating the equivalent hydraulic conductivity () and the coefficient of volume compressibility () of the part of the column improved layer have been proposed. The effectiveness of the method was verified by comparing predictions with the results of finite element analysis (FEA) using a unit cell model. The consolidation settlement (()) can be calculated by the method of treating a part of the column improved layer as an unimproved layer and using the corresponding average () value. By comparing the predicted results with the measurements of laboratory model tests and three case histories in Fukuoka, Japan, the effectiveness of the proposed methods has been verified. It is suggested that the method can be used for designing the soft clayey subsoil improvement using floating soil-cement columns.

关键词: cement depth mixing     ground improvement     consolidation     settlement    

深层搅拌桩墙围护结构裂缝成因探讨

高文华,王祥秋,陈秋南,张志敏

《中国工程科学》 2005年 第7卷 第12期   页码 88-91

摘要:

针对基坑支护中深层搅拌桩墙围护结构出现的开裂,采用Mindlin厚板理论对其受力与变形性状进行弹塑性分析,建立了墙体的厚板力学模型和三维有限元分析模型,并编制了有限元分析程序;基于墙体受到纵向弯矩、横向弯矩和扭矩的综合作用,提出采用等效弯矩法评价墙体的综合抗弯性能;利用所编制的程序,获得了某基坑深层搅拌桩墙围护结构墙体水平位移和等效弯矩的空间分布规律;计算结果表明,墙体东侧环球广场横向支撑附加力的作用是使墙体形成破裂面的主要原因。

关键词: 裂缝     深层搅拌桩墙     厚板     等效弯矩     三维有限元    

Transient process of methane-oxygen diffusion flame-street establishment in a microchannel

《能源前沿(英文)》 2022年 第16卷 第6期   页码 988-999 doi: 10.1007/s11708-021-0755-y

摘要: “Flame-street” is an interesting diffusion flame behavior in which a series of flame-segments is separately distributed along the mixing layer in a narrow channel. This experimental phenomenon was experimentally and numerically investigated with the focus on the steady-state, thermo-chemical flame structures in previous literature. In the present paper, the dynamic formation process of a methane-oxygen diffusion flame-street structure was simulated with a reacting flow solver developed based on the open-source framework OpenFOAM. By imposing a certain amount of ignition-energy near the channel outlet, a reaction-kernel was formed and bifurcated. Subsequently, three separate flames were consecutively generated from this kernel and propagated within the channel. The whole process was completed within 15 ms and all the discrete flames were eventually in a steady-state. Interestingly, different propagation features were observed for the three flame segments: The leading flame experienced a flame shape/type change from a tribrachial structure in its fast-propagating phase to a long, trailing diffusion tail after being anchored to the inlet. The successive flame had a much lower propagation speed, keeping its two wing-like (fuel-lean premixed and fuel-rich premixed) structure while moving toward its stabilization location, which was approximately in the middle of the channel. The last flame, after the ignition source was turned-off, was immediately convected a bit downstream, and eventually featured a similar two-branch-like structure as the second one. Moreover, chemical insights for the premixed and diffusion branches of the leading flame were also provided with the change of significance of some key elementary reactions focused on, in order to attain a detailed profiling of the flame-type transition. This paper is a first-ever one discussing the transient formation of flame-streets in literature and is believed to be useful for obtaining a comprehensive understanding of this unique flame characteristics from a dynamic point of view.

关键词: micro-combustion     flame-street     diffusion flame     mixing layer     flame propagation speed    

标题 作者 时间 类型 操作

A methodology of implementing target mixing ratio for asphalt mixture

Yucheng HUANG, Lun JI, Rui WEN, Ming ZHANG

期刊论文

Characterization of micro-mixing in a novel impinging streams reactor

Hui HU, Zhiming CHEN, Zhen JIAO

期刊论文

Chemical probe systems for assessing liquid–liquid mixing efficiencies of reactors

期刊论文

Combined static mixers for high viscous fluids mixing

Zhenhao XI, Weizhen SUN, Ling ZHAO, Zhaoyan LIU

期刊论文

Reliability-based settlement analysis of embankments over soft soils reinforced with T-shaped deep cement mixing

Chana PHUTTHANANON; Pornkasem JONGPRADIST; Daniel DIAS; Xiangfeng GUO; Pitthaya JAMSAWANG; Julien BAROTH

期刊论文

Characteristics and mixing state of S-rich particles in haze episodes in Beijing

Jun Hu, Fengkui Duan, Kebin He, Yongliang Ma, Shuping Dong, Xiande Liu

期刊论文

Dispersion of a novel phenolic rigid organic filler in isotactic polypropylene matrix by solution-mixingand melt-mixing

Dongming QI, Xiaoli ZHAO, Zhijie CHEN, Peng HUANG, Jun CAO

期刊论文

RETRACTED ARTICLE: Momentum exchange coefficient for two jet flows mixing in a tee junction

期刊论文

Reliability analysis of the control system of large-scale vertical mixing equipment

YANG Mingjin, LI Xiwen, LI Shaoping, YANG Shuzi

期刊论文

ALKALINE PRETREATMENT AND AIR MIXING FOR IMPROVEMENT OF METHANE PRODUCTION FROM ANAEROBIC CO-DIGESTION

期刊论文

Online single particle analysis of chemical composition and mixing state of crop straw burning particles

Juntao HUO,Xiaohui LU,Xinning WANG,Hong CHEN,Xingnan YE,Song Gao,Deborah S. Gross,Jianmin CHEN,Xin YANG

期刊论文

Continuous reaction performances of benzene alkylation with long chain olefins catalyzed by ionic liquid

QIAO Congzhen, LI Chengyue

期刊论文

A method for predicting consolidation settlements of floating column improved clayey subsoil

Jinchun CHAI, Supasit PONGSIVASATHIT,

期刊论文

深层搅拌桩墙围护结构裂缝成因探讨

高文华,王祥秋,陈秋南,张志敏

期刊论文

Transient process of methane-oxygen diffusion flame-street establishment in a microchannel

期刊论文