Table of Content

25 February 2014, Volume 42 Issue 2

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Chemistry & Chemical Engineering

Application of High- Efficiency Bamboo Lignin- Based Dispersant to Coal Phenol- Water Slurry

Yang Dong- jie Li Xu- zhao Li Hui- jing Jiang Hong- yan Li Qiong

2014, 42(2):  1-7.  doi:10.3969/j.issn.1000-565X.2014.02.001

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A series of high- efficiency bamboo lignin- based dispersants for the pulping of coal phenol- water slurrywere prepared by using bamboo black liquor as the main raw material. Then,the influences of relative molecularmass and sulfonation degree of the dispersant on the slurry fluidity were investigated. Furthermore, the effects of thetype and dosage of additive,the dispersant do- sage and the pulping temperature on the pulping performance and thestability properties of coal phenol- water slurry were discussed.The results indicate that (1) as compared withFDN,the dispersant with moderate sulfonation degree and medium relative molecular mass possesses better pulpingperformance in reducing the viscosity of coal phenol- water slurry; (2) the combination of sodium tripolyphosphateand the dispersant may reduce the apparent viscosity of the slurry and 15% is a suitable dosage of sodium tri-polyphosphate; (3) the apparent viscosity of the slurry continuously decreases with the increase of dispersant do-sage; (4) with the increase of pulping temperature,the apparent viscosity of the slurry first decreases and then in-creases,with its minimum occurring at 55℃; and (5) coal phenol- water slurry shows best stability properties atthe optimal dispersant dosage of 0.75%.

Preparation of Sodium Thiosulfate Pentahydrate as a Phase- Change Thermal- Storage Material

Gao Xue- nong Hu Xiao- dong Chen Si- ting Fang Yu- tang

2014, 42(2):  8-13,20.  doi:10.3969/j.issn.1000-565X.2014.02.002

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In order to overcome its supercooling and phase separation,Na₂S₂O₃ ·5H₂O ,a kind of phase- changematerial,was modified,with CaSO₄ ·2H₂O,naphthol as the nucleating agents,and with carboxymethyl cellulose(CMC),activated clay and solvable paraffin as the thickening agents. Then,the thermal storage/release perfor-mance of the modified Na₂S₂O₃ ·5H₂O  was investigated by using the cooling curve and the DSC analysis.The re-sults indicate that (1) CaSO₄ ·2H₂O,naphthol and naphthol- NaCl all play important role in the modification of Na₂S₂O₃ ·5H₂O ; (2) as compared with CMC，solvable paraffin and activated clay are of higher thickening effi-ciency for Na₂S₂O₃ ·5H₂O - CaSO₄ ·2H₂O with the same dosage of thickening agent; (3) Na₂S₂O₃ ·5H₂O  modi-fied with CaSO₄ ·2H₂O and activated clay achieves the crystallization and releases thermal energy at above 27℃,with the highest exothermic temperature varying from 43 to 48℃ and with an exothermic duration being more than80min; (4) Na₂S₂O₃ ·5H₂O modified with naphthol- NaCl possesses good stability and is of a phase- change tem-perature varying from 41 to 46℃ at different times of heat storing- releasing circulation,and the heat release evenlasts for more than 70 min; and (5) the phase change enthalpy of modified Na₂S₂O₃ ·5H₂O  varies from 150 to180J/g,while no phase separation occurs in the thermal storage/release process.

Comparison of ECF Short- Sequence Bleaching Processes for Bagasse Pulp

Li Jun He Shui- lin Li Zhi Xu Jun Mo Li- huan

2014, 42(2):  14-20.  doi:10.3969/j.issn.1000-565X.2014.02.003

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In this paper,first,three typical element chlorine- free (ECF) short- sequence bleaching processes,namely D₀ EpD,OpDEp and OpD,were comparatively investigated.Then,the difference in delignification rate be-tween the chlorine dioxide delignification (D₀ ) and the peroxide- reinforced oxygen delignification (Op) was re-vealed,and the effect of pre- delignification on the subsequent bleaching was analyzed.Finally,the AOX (Absor-bable Organic Halides) emission and the direct chemical cost during the bleaching were discussed.The results in-dicate that (1) D₀ possesses high delignification selectivity; for instance,the delignification rate reaches 40% at aClO₂ dosage of only 0.8% and continuously increases with ClO₂ dosage; (2) Op can not only delignify the residuallignin in pulp but also remarkably improve the pulp brightness to a value much higher than that of D₀ pulp; (3)OpDEp bleaching is more effective than D₀ EpD bleaching at the same chemical dosage in the subsequent bleachingbecause it may result in higher pulp brightness; (4) the final brightness of OpDEp bleached pulp is about 12 per-centage points higher than that of OpD bleached pulp; and (5) at the same pulp brightness,the AOX emitted du-ring the OpDEp bleaching is only about half of that emitted during the D₀ EpD bleaching,and the direct chemicalcost of OpDEp bleached pulp is 40. 00 Yuan/t lower than that of D₀ EpD bleached pulp,which means that OpDEpbleaching is of higher environmental and economic benefits.

Mechanism of Interaction of Resveratrol Dimer with Cobra Neurotoxin

Ye Yong Xing Hai- ting Guo Ya

2014, 42(2):  21-26,32.  doi:10.3969/j.issn.1000-565X.2014.02.004

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The interaction of various resveratrol dimers with cobra neurotoxin (NT) was simulated with DiscoveryStudio software.Then,the dimer was photo- induced by light with a wavelength of 365 nm,and the UV- Vis andfluo- rescence spectra of NT mixed with resveratrol were analyzed at different resveratrol concentrations and illumina-tion durations.Finally,the binding energy and some other parameters of the interaction were calculated.The re-sults show that (1) resveratrol dimer is of higher binding energy and stronger interaction than the monomer; (2)some changes occur in the spectra after the illumination,such as enhanced ultra- violet absorption,red- shifted ab-sorption peak,fluorescence quenching and new emission peak; (3) the fluorescence quenching is a static quench-ing with a rate constant of 5.62 × 10 12 L/( mol · s); (4) the binding constant of resveratrol and NT is 5.12 ×10 5 L/mol,the number of binding sites is 1,and the binding distance is 3.40 nm,which may easily resultin non- radiation energy transfer; (5) as illustrated by synchronous fluorescence spectra,the dimer can interact withtyrosin and tryptophan residues of NT and hydroxyl hydrogen bonds may contribute to the improvement of hydrophi-licity; and (6) the main interaction site of NT with resveratrol dimer is the tryptophan residue.

Butanol Production from Corn Stover by Fermentation with Clostridium acetobutylicum

Ma Xiao- jian Zhang Xia Chang Chun

2014, 42(2):  27-32.  doi:10.3969/j.issn.1000-565X.2014.02.005

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In this paper,butanol was prepared from the enzymatic hydrolysate supermatant of steam- exploded cornstover,with Clostridium acetobutylicum as the experimental bacterium. Then,the effects of supermatant concentra-tion,initial pH value and microbial inoculation quantity on butanol yield were investigated,and the optimal dosagesof nutrient elements were determined by orthogonal test.The results show that,under optimal conditions,that is,asupermatant sugar content of 57.5g/L,an initial pH value of 6.3,an inoculation quantity of 6%,a fermentationtemperature of 37 ℃,and a nutrient elements addition of yeast extract 0.8g/L + CH₃ COONH₄ 6. 0g/L + KH₂ PO₄ 0. 5g/L + nicotinamide 0.25g/L,the butanol yield is up to 9.726g/L.Moreover,it is also found that there existsome inhibitors for the solvent production from steam- exploded corn stover enzymatic hydrolysate,and that a smallamount of nicotinamide may effectively promote butanol production.

Synthesis and Properties of Transparent Fluorinated Polyurethane Coatings

2014, 42(2):  33-38.  doi:10.3969/j.issn.1000-565X.2014.02.006

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Polyisocyanate and dihydric alcohols with different fluorocarbon chain lengths were used as raw materialsto synthesize a series of fluorinated isocyanate prepolymers,and the prepolymers were then reacted with self- maderandom copolymerized polyester polyol to prepare transparent fluorinated polyurethane coatings.Afterwards,avariety of analytical methods were used to characterize the structure and properties of the coatings,and the effect offluorocarbon chains on the coating properties was finally discussed.The results indicate that (1) the introduction offluorocarbon chains increases the internal short- range ordered structure in polyurethanes,with an increase degreebeing inversely proportional to the length of fluorocarbon chains,which leads to a decline of coating transparency;(2) the mechanical properties of polyurethanes degrade with the introduction of fluorocarbon chains,and the degra-dation slows down in the presence of moderate micro- phase separation in fluorinated polyurethanes; (3) the intro-duction of fluorine improves the thermal resistance of polyurethanes,especially under the condition of shorter fluoro-carbon chains; (4) the fluorine in fluorinated polyurethanes may migrate to the surface and reduces the surface en-ergy,and the migration degree is related to the crystallization degree of fluorinated isocyanate; and (5) moderatecrosslinking and the migration of fluorine may lead to excellent water resistance of fluorinated polyurethanes.

Effective Thermal Conductivity of Graphite- Based Microfluids

Cui Guo- gen Xiao- xi Ding Jing Yang Jian- ping

2014, 42(2):  39-43.  doi:10.3969/j.issn.1000-565X.2014.02.007

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Graphite- based microfluids were prepared via the one- step chemical method,and the effective thermalconductivity of the microfluids was measured by means of the transient hot wire method under the conditions of dif-ferent graphite contents,different ultrasonic time,different microwave time and base fluids.The results show that(1) the addition of graphite in the base fluids greatly improves the effective thermal conductivity of the microfluids;(2) the effective thermal conductivity of microfluids increases with the increase of the graphite content; (3) the ef-fective thermal conductivities of graphite- based microfluids in three base fluids (DI water,ethylene glycol and dim-ethicone) respectively increase by 102． 09%,93.17% and 225.69% at the graphite content of 1. 0%; (4) at thesame graphite content,the same ultrasonic time and microwave time,dimethicone may result in the largest effectivethermal conductivity increment while DI water may result in the smallest one; and (5) with the prolonging of ultra-sonic time and microwave time,the increment of effective thermal conductivity of graphite- based microfluids signifi-cantly reduces.

Certification of Dienestrol Purity Reference Material and Its Uncertainty Evaluation

2014, 42(2):  44-49,56.  doi:10.3969/j.issn.1000-565X.2014.02.008

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In this paper,first,certified reference material (CRM) for the purity determination of dienestrol wasprepared by means of semi- preparative high- performance liquid chromatography. Next,a qualitative analysis of theraw materials was performed by using liquid chromatography- mass spectrometry,1H NMR,13C NMR and infraredspectroscopy.Then,the content of organic main ingredients in the prepared CRM was determined via the multi- labcertification with HPLC,and the homogeneity and stability of the CRM were measured. Moreover, the contents ofwater,ash,volatile materials and inorganic elements were analyzed,with an uncertainty evaluation of the CRM be-ing finally carried out.The results indicate that (1) the prepared CRM possesses good homogeneity and is of a sta-ble storage period of 12 months; (2) the contents of water,ash,volatile materials and inorganic elements in theprepared CRM of dienestrol are all less than 0.1%; and (3) the prepared CRM is of a certified purity of 99.4%and a relative expanded uncertainty of 0.6% (k =2).

Architecture & Civil Engineering

Mechanical Properties of Waste Concrete- Participated Recycled Concrete

Zhu Ci- mian Li Tan

2014, 42(2):  50-56.  doi:10.3969/j.issn.1000-565X.2014.02.009

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In order to reduce the production cost of recycled aggregate and improve the utilization rate of waste con-crete in common engineering application of recycled concrete,a new type of recycled concrete material named wasteconcrete- participated recycled concrete was prepared by straightly blending wet and broken waste concrete blockwith fresh concrete. The maximum size of waste concrete block for blending is up to 50 ～80mm,which may expandthe superiority of waste concrete in reducing the production cost and improving its utilization rate.Then,mechani-cal behavior studies were conducted for the 150 or 300mm module specimens and the slabs of waste concrete- partici-pated recycled concrete. The results show that,even when the participation rate of waste concrete reaches 30% ～40%,the compressive strength,tensile strength and elastic modulus of the prepared recycled concrete are veryclose to those of common concrete in the same strength grade,which means that the recycled concrete possessesideal mechanical properties. Moreover,it is also found that both the punching bearing capacity and the failure cha-racteristics of the recycled concrete slabs are very close to those of common concrete slabs.

Stochastic Analysis of Compressive Capacity of Thin- Wall Circular Steel Tubular Columns Filled with Demolished Concrete Blocks Based on Fiber Beam Element

Zhao Xin- yu Wu Bo Yang Yong

2014, 42(2):  57-63,80.  doi:10.3969/j.issn.1000-565X.2014.02.010

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First,based on the calculation framework of the fiber beam element model,a stochastic numericalmethod to analyze the compressive capacity of thin- wall circular steel tubular columns filled with demolished con-crete blocks(DCBs) and fresh concrete(FC) is proposed by introducing the technique of generating random DCBsparticles and subsequently packing them randomly in the cross- sections at integration points of a fiber beam ele-ment.Then,a computer program is accordingly developed,and the validity of the proposed method is initially veri-fied by comparing the numerical results with the published test ones.The comparison shows that the non- uniformdistribution of DCBs in column cross- sections has no significant effect on the initial stiffness of the columns,but hasa certain effect,which increases with the decrease of steel wall thickness,on the compressive softening behavior.Finally,with the help of the proposed method,the compressive capacity of the columns affected by such parametersas the length- to- diameter ratio,the steel wall thickness,the replacement ratio of DCBs and the strength differencebetween the new and the old concrete in the steel tube,is investigated.The results indicate that,when the replace-ment ratio of DCBs varies from 25% to 40% or the strength difference between the new and the old concrete is notlarger than 15 MPa,the influence of the non- uniform distribution of DCBs on the compressive capacity of thecolumns is similar,while the influence increases with the decrease of the steel wall thickness or the length- to- diam-eter ratio at small eccentricity as well as with the decrease of the eccentricity.

Effect of Simulated Drying- Wetting Environment on Water Influence Depth in Concrete

Liu Peng Song Li Yu Zhi- wu

2014, 42(2):  64-73.  doi:10.3969/j.issn.1000-565X.2014.02.011

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In this paper,first,an equilibration time ratio model of water influence depth in concrete is established,and the equilibration time ratio in simulated environment,which is influenced by three parameters,namely,thewater- to- cement ratio,the initial concrete saturation,and the environment saturation around concrete surface,is in-vestigated.Then,the relationships between the three parameters and the water influence depth in concrete are ana-lyzed via numerical calculation,and a model describing the water influence depth is constructed. Finally,thedifferences and similarities of the solving methods for equilibration time ratio are discussed.The results show that(1) different solving methods help to obtain the same equilibrium time ratio that basically accords with the test re-sults; (2) there exists an obvious exponential relationship between the equilibration time ratio and such parametersas the water- to- cement ratio,the initial concrete saturation and the environment saturation around concrete surface;and (3) the water influence depth in concrete is linear to the square root of wetting time.

Research on Concrete Creep and Relaxation Based on the Generalized Kelvin Model with Variable Coefficients

Zhang Jun Duan Ya- hui

2014, 42(2):  74-80.  doi:10.3969/j.issn.1000-565X.2014.02.012

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In this paper,first,a Dirichlet series expression of concrete creep based on the generalized Kelvin mod-el with variable coefficients is suggested,and a creep expression with nine parameters is proposed based on the con-tinuous retardation spectrum.Then,an expression of relaxation coefficient rate is derived and a rate- type superposi-tion algorithm is further proposed to calculate the relaxation coefficient.Finally,by using some experimental data,the suggested creep expression and the rate- type superposition algorithm are respectively compared with the commonones.The results indicate that (1) the proposed creep expression possesses explicit physical meaning and helps toavoid negative creep; (2) the creep expression with nine parameters is of higher fitting precision,as compared withthe expression with eight parameters; and (3) the proposed rate- type superposition algorithm helps to avoid the er-ror propagation existing in the traditional superposition algorithm and greatly improves the fitting precision of theearly- age concrete at longer lag- time stage.

Laboratory Test and Parameter Back Analysis of Residual Strength of Slip Zone Soils

Liu Dong Chen Xiao- ping

2014, 42(2):  81-87.  doi:10.3969/j.issn.1000-565X.2014.02.013

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Systematic ring shear tests of the sand clay in an ancient landslide were carried out in laboratory to revealthe effect of coarse grain content on the residual shear character and residual strength of slip zone soils,and a backanalysis was carried out with multiple similar sections.Then,the calculated residual strength was comprehensivelycompared with that obtained by laboratory test,with a suitable residual strength of ancient landslide being recom-mended.The results show that (1) the ring shear test is an ideal method to obtain the residual strength under largeshear displacement; (2) different from common clay,the slip zone soil is of no obvious strain- softening character,and the strain softening becomes weaker when the coarse grain content increases; and (3) at high coarse grain con-tent,the equivalent residual internal friction angle nonlinearly increases with the coarse grain content.

Numerical Method of Determining Installation Force for Parallel Strand Cables

Zhang Zhuo- jie Wang Rong- hui

2014, 42(2):  88-95,102.  doi:10.3969/j.issn.1000-565X.2014.02.014

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Based on the basic stretch- draw principle of parallel strand stay cables,formulas respectively describingthe configuration of target state and the unstressed cable length were set up according to the catenary theory.Then,two problems existing in the stretch- draw process of parallel strand stay cables were put forward,and the corre-sponding solving methods were proposed and a calculation program was compiled with Matlab to determine the sin-gle strand initial tension.Finally,a case study on the Tongling rail- road cable- stayed bridge under construction wasconducted.The results show that the proposed method is effective and reliable,and that it may provide theoreticalreferences for the construction of parallel strand stay cables.

Traffic & Transportation Engineering

Investigation into Generation of Transit Station OD Matrix Based on Coulomb's Law

Zhao Shu- zhi Zhang Xiao- liang Liu Hua- sheng Gao Xiang- tao

2014, 42(2):  96-102.  doi:10.3969/j.issn.1000-565X.2014.02.015

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In order to obtain a reasonable public transit assignment,by introducing the Coulomb's Law,intercelland intracell models for generating transit station OD matrix are proposed according to the distribution of transit sta-tions in a traffic zone.Then,the models are optimized according to the characteristics of different transit stations.Moreover,a sensitivity coefficient analysis is carried out and the corresponding solving model is constructed.Final-ly,the effectiveness of the model is verified through a case study.The results show that the proposed model is ofhigh theoretical and practical value and helps to improve the reliability of the forecast of transit passenger flow.

Practical Method of MNP Model Parameter Estimation and Its Application to Forecast of Trip Mode Choice

Yu Li- jun Wang Lei- yun

2014, 42(2):  103-108,138.  doi:10.3969/j.issn.1000-565X.2014.02.016

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As estimating MNP model parameters using the SML- GHK method is sensitive to the initial values,apractical method for initial value determination and parameter estimation is proposed.It uses the Bayesian approachto define the initial values of MNP model parameters,and adopts the simulated maximum likelihood based on GHKframework to estimate the MNP model parameters.Then,a case study is performed to verify the effectiveness of theproposed method.The results show that (1) the proposed method is applicable and effective,especially for small-scale samples; (2) using parameters defined by the proposed approach,better trip mode share forecast results canbe achieved ; and (3) it is a useful tool for transport planners to exam the probability variations of trip mode choiceresulted by transport policy changes.

Prediction of Expressway Travel Time Based on Adaptive Interpolation Kalman Filtering

Zhao Jian- dong Wang Hao Liu Wen- hui

2014, 42(2):  109-115.  doi:10.3969/j.issn.1000-565X.2014.02.017

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Poor adaptability of Kalman filtering algorithm may result in inaccurate prediction of expressway traveltime when the traffic flow between two expressway toll stations is non- stationary.In order to solve this problem,aprediction algorithm based on the equidistant interpolation and the Sage- Husa adaptive Kalman filtering is proposed.In the investigation,first,data from manual toll collection and electronic toll collection are merged together to cal-culate the average travel time.Then,the time series between real- time and historical travel time is reconstructedvia the equidistant interpolation,and a prediction model based on the Sage- Husa adaptive Kalman filtering is con-structed with the help of the least square method.Moreover,a prediction system of expressway travel time is deve-loped and is finally applied to the real- time prediction of the travel time between two toll stations.Case study resultsof an expressway section show that,in the three states,namely,the normal state,the accident state,and the holi-day state,the proposed algorithm is able to restrict the average relative error of all periods or of a random accidentwithin 7.5% or 10%,respectively.

Optimization of Vehicle Routing Problem Based on Multiple Customer Characteristics

Wang Yong Mao Hai- jun Liu Yong He Jie

2014, 42(2):  116-124.  doi:10.3969/j.issn.1000-565X.2014.02.018

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In order to overcome the shortcomings of the traditional vehicle routing optimization study in terms ofcustomers' commodity demand characteristics,a clustering analysis- based routing optimization using multiple cus-tomer characteristics is proposed.In the investigation,first,linguistic variables are represented by trapezoidal fuzzynumber to implement a comprehensive evaluation of both customers and sub- criterion indices.Next,the sub- criteri-on indices are integrated into a major criterion index via fuzzy integration,and the integrated major criterion value issplit into four sub- criterion values for clustering operation,with a clustering validity index being designed to choosereasonable clustering results.Then,the fuzzy TOPSIS method is used to calculate the customer priority weights foreach cluster.Moreover,evaluation functions for selected customer services are established and are combined withthe dynamic programming method for vehicle routing optimization.Finally,the effectiveness of the proposed methodis verified through an example,and is compared with the existing methods.The results show that the proposedmethod is superior to the method only based on distance measure or customer priority weights,and that it helps toobtain reasonable vehicle routing even in the presence of large- scale customers.

Behavior Model of Urban Trip Chains in Multi- Mode Transportation Network

Zhou Jia- zhong Zhang Dian- ye

2014, 42(2):  125-131.  doi:10.3969/j.issn.1000-565X.2014.02.019

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In order to overcome the deficiencies of the existing behavior models of trip chains for urban transporta-tion,the basic concept of the urban trip chain and the possible paths in a simple trip chain were analyzed,and amodel based on the entropy- maximizing (EM) model was proposed to describe the trip chain behavior in a multi-mode transportation network,in which origin- destination constraints and travel distance constraints were introduced.Then,the corresponding parameter estimation procedure and prior probability setting method were given.Finally,the model was applied to the analysis of sample data of the resident trip survey in the inner city of Chengdu,with itseffectiveness being verified by 5 benchmark indexes including the travel distance of trip chains,the trip flow be-tween zones of trip chains,the number of trip chains approaching different zones,the individuals of different tripchains and the individuals of different types of trip chains.The results show that the proposed model accords wellwith real values,so that it can be used as an effective modeling tool for analyzing urban transportation travel.

Data Mining Method of Road Transportation Management Information Based on Rough Set and Association Rule

Zheng Xiao- feng Wang Shu

2014, 42(2):  132-138.  doi:10.3969/j.issn.1000-565X.2014.02.020

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As the data of the road transportation management information system are mostly inconsistent,impreciseand incomplete,a novel data mining method,which combines the rough set analysis with the classical associationrule,is proposed based on the system induction idea and the attribute reduction method of the rough set theory.Then,the relationship among the rule number,the support degree and the confidence is analyzed by using therough set method,and the reliability and validity of the proposed method is verified through a case study.The re-sults indicate that the proposed method can realize an attribute reduction of 33.3%,which means that the methodis effective in solving the problems existing in the real road transportation management system.

Prediction of Fatigue Life of Asphalt Mixture Based on Strain Control

Wu Zhi- yong Zhang Xiao- ning You Hong Yuan Miao- miao Wan Cheng

2014, 42(2):  139-144.  doi:10.3969/j.issn.1000-565X.2014.02.021

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Four- point bending beam fatigue tests of three kinds of graded asphalt mixtures were carried out in thestrain control mode,and two criteria for fatigue life prediction,namely the catastrophe point of the relative changerate of dissipated energy (Criterion 1) and the stiffness modulus decreasing to 50% of the initial stiffness modulus(Criterion 2),were compared.Then,two fatigue life prediction models respectively corresponding to the two crite-ria were constructed.The results show that (1) the initial stiffness modulus of the mixture decreases with the in-crease of strain level and nominal maximum particle size; (2) when Criterion 1 is used as the failure criterion,thesame mixture mostly destroys with the same stiffness modulus at different strain levels,the destruction stiffnessmodulus of different mixtures decreases with increase of nominal maximum particle size,and the predicted fatiguelife is longer than that predicted by Criterion 2; (3) the fatigue life of asphalt mixture significantly decreases withthe increase of the strain level and the nominal maximum particle size; and (4) the fatigue life prediction modelcorresponding to Criterion 1 is of higher accuracy.