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Table of Content

    25 February 2012, Volume 40 Issue 2
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    Architecture & Civil Engineering
    Analysis of Pancake Collapse of RC Space Slab-Column Structures under Earthquake
    Wu Bo Wang Ming-jun
    2012, 40(2):  1-6. 
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    Based on the test results of two three-story RC ( Reinforced Concrete) space slab-column structure models with weak stories,the interstory shear force-time curve during the pancake collapse under earthquake is analyzed for each story and is compared with that before the collapse. Then,the equivalent interstory shear force and its impulse on each story in the impact process are approximately estimated and compared with the lateral impulse to the upper structure of a simple model in the static initial state. The results show that ( 1) pancake collapse impact results in equivalent interstory shear forces with large values and very short durations in each story of the test model,which is a challenge to the lateral deformation-resisting capacity of non-weak stories; ( 2) with the increase in the structural weight over the weak story,the interstory shear forces in the impact process significantly increase;
    and ( 3) under the pancake collapse impact,the lateral impulse to the upper structure of a simple model in the static initial state is about 4 ～ 5 times that of the test model at the same location with an equivalence point being zero percentage.

    Analytical Algorithm of Transverse Vibration Frequency of Cables with Intermediate Flexible Supports
    Li Ping-jie Wang Rong-hui Ma Niu-jing
    2012, 40(2):  7-12,18. 
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    In this paper,a beam model with intermediate flexible supports under axial force is established by taking the elastic support reaction as a compelling force loading on the beam and by comprehensively taking into consideration the vibration factors of cables such as the axial force,the bending stiffness and the boundary condition of the ends.  Based on the model,an analytical algorithm is proposed to calculate the transverse vibration frequency of the cables with intermediate flexible supports. The analytical results are then compared with the test ones under different axial forces. It is found that only a small deviation with a maximum of 1.6% is observed,which means that the proposed algorithm is feasible.

    Monitoring and Analysis of Wind Effect on Membrane Roof of Expo Axis
    Zhu Bing-hu Zhang Qi-lin
    2012, 40(2):  13-18. 
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    In order to deeply investigate the wind pressure distribution and wind vibration characteristics of complex cable-membrane roof in real environment,a two-year wind effect monitoring of the Expo Axis was carried out. By analyzing the data recorded in a strong wind process in July,2011,the wind environment and wind pressure distribution of the roof were obtained and compared with those obtained by wind tunnel test. Analytical results indicate that ( 1) negative wind pressure predominates at the wind inflow side of the roof of the Expo Axis,while positive wind pressure predominates at the other side; ( 2) the pulse wind pressure on the edge of the wind inflow side is high,while that at the other side is relatively low; ( 3) both the average and the pulse wind pressure coefficients decrease with the roof height; ( 4) the average wind pressure coefficient is basically insensitive to the wind speed; and ( 5) though the wind pressure coefficient measured in real environment is less than that measured by wind tunnel test,they both possess similar distribution trend.

    Mechanics
    Stress Analysis of Box Girder with Corrugate Steel Webs Under Torsion
    Yang Bing-wen Li Ya-le Wan Shui Zhang Jian-dong
    2012, 40(2):  19-22,34. 
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    As compared with common concrete box girders,box girders with corrugated steel webs are of lower torsional rigidity and greater torsional normal stress due to their structural particularity. In order to deeply investigate the warping stress loading on the box girders with corrugated steel webs under torsion,corrugated steel webs are taken as orthotropic plates based on the theory and the mechanical characteristics of box girders,with corrugated steel webs,and a torsion differential equation of box girders with corrugated steel webs is deduced by using the second theory of Wu. Then,the constraint torsional normal stress and shear stress are calculated by employing the initial parameter method,and the results are compared with the test ones. It is found that the stress analysis in this paper is correct and more precise.

    Mechanical Properties of the Double Main Cables Suspension Bridge (Ⅱ)
    Chai Sheng-bo Xiao Ru-cheng Sun Bin
    2012, 40(2):  23-28. 
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    This paper deals with the mechanical properties of a suspension bridge with double main cables under unbalance load. The double-main cable system can be equivalent to a virtual main cable according to the distribution of the load between the top cable and the bottom cable. Under single-span load,the cable force on the load span increases,the load on the adjacent span transfers from the bottom cable to the top cable,and the sag of the virtual cable decreases,so that the cable force balances with the load span. According to the equivalent relation of the cable force between the load span and the adjacent span,the distribution ratio of the cable force loading on the top cable and the bottom cable is obtained by calculating the sag of the virtual cable. Moreover,a finite element model is established to verify the proposed theory,and the results are compared with the theoretical ones. It is found that both the deformation of the pylon and the mid-span deflection of the double-main cable system under unbalanced live loads are much less than those of the traditional suspension bridge.

    Molecular Dynamics Simulation of Tensile Properties of Graphene Sheets
    Han Qiang Huang Ling-yan
    2012, 40(2):  29-34. 
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    In this paper,the mechanical properties of monolayer and multilayer graphene sheets under tension in two directions were investigated via molecular dynamics simulation,and the corresponding stress-strain relationships and tensile failure modes were discussed. Then,the size effect and the layer effect on the tensile properties of graphene sheets were analyzed by respectively changing the size of the monolayer graphene sheet and the layer number of the multilayer graphene sheet. The results show that ( 1) the monolayer graphene sheet,of which the elastic moduli are respectively 1078.02GPa ( armchair) and 1041.53GPa ( zigzag) ,is isotropic in the linear stretched elastic deformation stage,and its tensile properties are insensitive to size; ( 2) the multilayer graphene sheet is of a stress-strain relationship similar to that of the monolayer graphene sheet and it shows a more obvious isotropic nature in the linear stretched elastic deformation stage; and ( 3) the tensile failure of armchair graphene sheets starts from one side and extends inwards along the 45°direction,while that of zigzag graphene sheets starts from both sides and extends inwards in a symmetrical manner.

    Molecular Dynamics Simulation of Buckling of Defective Double-Wall Carbon Nanotubes Under Axial Compression
    Xin Hao Han Qiang
    2012, 40(2):  35-38,44. 
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    In order to fully reveal the mechanical properties of double-wall carbon nanotubes ( DWCNTs) ,the bulking of the nanotubes under axial compression is investigated through the molecular dynamics simulation,and the bearing properties and the deformation of the individual inner and outer layers are emphatically analyzed and compared by taking into consideration the defect of the inner tube. The results show that,for a double-wall nanotube fabricated with two single-wall nanotubes,the bearing capacities of both the inner and the outer tubes greatly improve even though the inner tube is defective,and that,when the force is exerted only on the inner tube,the deformations of the inner and the outer tubes are inharmonious.

    Space-Time Unsteady Flow of Moving Grids in Pelton Bucket Based on Differential Geometry
    Shen Na Han Feng-qin Kubota Takashi
    2012, 40(2):  39-44. 
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    In order to apply the concept of unsteady flow in space and time domains to the design of Pelton buckets,a numerical visualization of the complicated unsteady water film flow on the free surface of a rotating bucket is indispensable. In this paper,the inner surface of a bucket is described by using the boundary-fitted grids with nonorthogonal curvilinear local coordinates. Then,the natural basic vectors and their partial differentials are precisely
    acquired based on the differential geometry,and the local curvature along the inner surface,the geodesic and the small surface area of the bucket are obtained. Moreover,the moving grids of the water film are successfully projected onto the bucket’s inner surface,and a projection algorithm is proposed to numerically visualize the moving grids of the unsteady water film flowing from the bucket cutout and the water separation edge. The visualization results are finally compared with the photos taken in the model test,which verifies the effectiveness of the proposed method.

    Traffic & Transportation Engineering
    Performance Analysis of Simulation of Pedestrian Traffic in Public Buildings
    Weng Xiao-xiong Huang De-jian Li Sheng-fu
    2012, 40(2):  45-49,69. 
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    The pedestrian traffic system in public buildings is a nonlinear stochastic dynamic system with uncertain cluster density and interactive individuals. At present,computer dynamic simulation is one of the effective methods to investigate the dynamic characteristics of pedestrian traffic flow in public buildings. In this paper,aiming at the difference in simulation results of pedestrian evacuation obtained by several major simulation softwares in the same scene,the performance differences of the simulation software models are discussed,the simulation error due to the discrete space is analyzed,and the accuracy of the simulation models is evaluated by means of fidelity analysis. By comparing the simulated results of the travel time in the channels of the metro station with the experimental ones,it is found that the simulation performance of pedestrian traffic is closely related to the building environment,and that fidelity is important to the simulation model. Moreover,case study indicates that the multi-agent simulation model based on continuous vector space is of a fidelity up to 87% for reproducing the pedestrian behaviors in complex public buildings.

    Reliability of Regional Bus Scheduling Problem
    Wei Ming Jin Wen-zhou Sun Bo
    2012, 40(2):  50-56. 
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    As the emergencies such as traffic congestion may interfere with vehicles to complete a trip on time and may further result in the failure of relevant bus scheduling scheme,it is highly necessary to establish a high-reliability scheme which adapts to the traffic environment change. In this paper,based on the assumption that the delay time caused by uncertain factors follows the normal distribution and that the regional bus scheduling problem can be regarded as a set-partitioning problem of“part of trips are completed by a vehicle”,the concept of reliability is introduced to formulate the regional bus scheduling scheme as a multi-objective programming problem with the minimum cost of vehicles as the previous objective and with the maximum reliability as the secondary objective. Then,the constraint method is used to convert the secondary objective into the corresponding constraint,which makes the model to be a single-objective programming problem. Moreover,an improved genetic algorithm,which redesigns a chromosome coding,a fitness function,a heuristic procedure for population initialization and the crossover /mutation operation according to the features of bus scheduling,is designed to solve the problem. An example is finally given to show the correctness and effectiveness of the proposed model and algorithm.

    Parallel Microscopic Simulation System of Mixed Traffic Based on Multi-Core Technology
    Li Shan-shan Qian Da-lin Wang Jiu-zhou
    2012, 40(2):  57-62. 
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    In order to speed up the microscopic simulation of mixed traffic,a simulation platform based on the multi-core parallel computing technology is proposed. The proposed platform is described in two aspects,namely the functional structure and the design as well as the implementation of the simulation process. Then,some key algorithms for implementing the microscopic simulation,namely the initial transportation network segmentation algorithm, the crossing border algorithm of vehicles and the dynamic load-balancing algorithm,are designed and implemented. Simulated results show that the adoption of multi-core parallel computing technology greatly improves the microscopic simulation efficiency of mixed traffic.

    Dynamic Analyses of Travel Time and Route Choice Probability of Users in Accidents
    Chen Ling-juan Liu Hai-xu Pu Yun
    2012, 40(2):  63-69. 
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    In order to reveal the interaction and its evolution rule between route travel time and route choice probability in traffic accidents,a quasi-dynamic model is established based on the link transmission model and the LOGIT model,and the methods to calculate the travel time and the traffic flow density are respectively presented. Then,the corresponding queue dispersing and dissipating courses are analyzed. The results indicate that the route travel time and the route choice probability rise and subside alternately and remain in a concussed condition during the accident and in the queue dispersing process,and that the queue spot transfers in the accident duration and in the clearing period.

    Nonlinear Output Feedback Control of Dynamic Positioning System of Ships
    Du Jia-Lu Li Wen-hua Zheng Kai Yu Shuang-he
    2012, 40(2):  70-75,91. 
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    In order to overcome the non-measurability of the velocity of dynamic positioning ships,a nonlinear observer-controller scheme with separate stability for the observer is proposed based on the nonlinear mathematical model of ship movement with environmental disturbances. The proposed scheme implements the output feedback control of ship dynamic positioning systems with position and orientation measurements only. The resulting output feedback closed-loop control system of dynamic positioning ships is proved to be globally and asymptotically stable by applying the cascaded nonlinear system theory,and the designed output feedback control law forces the ship position and orientation to globally and asymptotically converge to their desired values. Simulation results on a supply ship verify the effectiveness of the proposed output control law for the dynamic positioning of ships.

    Modeling and Optimization of Shift Process of a Novel Power Shift Transmission
    Tan Di Luo Yu-tao
    2012, 40(2):  76-81. 
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    Proposed in this paper is a novel power shift transmission that inherits the advantages of power shift of dual-clutch transmission and achieves more speed ratios with limited gear pairs. Then,based on further analyses of the structure and the mechanism of the transmission,a dynamic simulation model containing the shift dynamics models and the shift control models is established for the vehicle drive system,and the factors affecting the shift quality are analyzed and optimized. Moreover,in order to verify the shift performance,the proposed simulation model is applied to the successive upshift of the transmission. The results show that the novel power shift transmission not only achieves 2( n + m) speed ratios with n + m fixed-axis gear pairs but also ensures high power shift quality.

    Sliding Characteristics of Traction Drive Device Under Hydraulic Pressing
    Shen Chu-jing Yuan Shi-hua Wei Chao
    2012, 40(2):  82-86. 
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    In this paper,the transmission principle of the traction drive device under hydraulic pressing was analyzed,and the variations of the traction coefficients of the inner and outer friction pairs with the transmission ratio were explored. Then,a method to analyze the sliding characteristics of the traction drive device was investigated. Moreover,a mathematical model and a method to investigate the transmission traction characteristics were proposed based on the elasto-hydrodynamic lubrication theory,which were then used to explore the power characteristics of the friction pairs under different slide-roll ratios and normal pressing forces and to obtain the input and output powers at different total sliding rates. The results show that (1) at a constant sliding rate,the transmission power of the traction drive device under hydraulic pressing increases with the normal pressing force and tends to a constant when the shear stress approaches the ultimate value; (2) under a constant normal pressing force,the transmission power first increases and then decreases with the increase in the sliding rate; and (3) at a constant transmission power,the sliding rate decreases with the increase in the normal pressing force,which may result in high transmission efficiency.

    Experimental Investigation into Pavement Performance of Buton Rock Asphalt Mixtures
    Huang Wen-tong Xu Guo-yuan
    2012, 40(2):  87-91. 
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    In order to evaluate the properties of asphalt mixtures modified by Buton rock asphalt ( BRA) ,A-70 asphalt was used as the base asphalt to test the pavement performances of modified asphalt mixtures with different BRA dosages. The results show that (1) the Marshall stability,the splitting strength and the water stability of BRA mixtures are all higher than those of A-70 asphalt and SBS modified asphalt mixtures; (2) the dynamic stability of BRA mixtures is much stronger than that of A-70 asphalt mixtures but is similar to that of SBS modified asphalt mixtures; (3) though BRA helps to effectively improve the low-temperature performance of asphalt mixtures,its dosage should not exceed 25% in engineering because the low-temperature performance of the mixtures degrades when the BRA dosage increases from 20% to 25%.

    Investigation into Close-Grained Gradation of Aggregates Skeleton Under Strong Interlocked Force via PFC2D Numerical Test
    Jiang Ying-jun Ren Jiao-long Li Di Xu Yin-shan
    2012, 40(2):  92-98,103. 
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    In order to well optimize the mineral gradation,a method to numerically test the compactness and the California bearing ratio ( CBR) of aggregates via PFC2D was proposed. Then,based on the reliability analysis,the variation laws of the compactness and the CBR were analyzed respectively for synthetic coarse aggregates,synthetic fine aggregates and coarse-fine combined aggregates,and a close-grained gradation of aggregates skeleton under strong interlocked force was proposed. Moreover,the mechanical performances of the aggregates skeleton were verified through laboratory tests. The results show that the optimal mass ratios of the coarse aggregates with the diameters of 19~31.5mm,9.5~19mm and 4.75~9.5mm are respectively 0 ∶ 20 ∶ 10,60 ∶ 30 ∶ 10,60 ∶ 20 ∶ 20 and 50 ∶ 30 ∶ 20,while those of the fine aggregates with the diameters of 2.36~4.75mm,0.6~2.36mm and less than 0.6mm are respectively 38.5 ∶ 16.5 ∶ 45、33 ∶ 22 ∶ 45,36 ∶ 24 ∶ 40 and 30 ∶ 30 ∶ 40,and that the optimal mass ratio of coarse-fine combined aggregates is 65 ∶ 35. It is also found that the graded broken stone composed of the aggregates skeleton with close-grained gradation under strong interlocked force is of excellent mechanical properties because its CBR and compressive strength are respectively 1.16 and 1.12 times those of the standard gradation.

    Fatigue Performances of Modified Asphalts Based on Cumulative Dissipated Energy Ratio
    Meng Yong-jun Zhang Xiao-ning
    2012, 40(2):  99-103. 
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    In this paper,the rheological properties of different modified asphalts are experimentally investigated,and the fatigue performance index based on the cumulative dissipated energy ratio ( DER) is analyzed. Then,the fatigue performances of modified asphalts with different block ratios are discussed and compared according to the DER. Moreover,according to the fatigue performances of modified asphalts,some bending fatigue tests are carried out. The results show that DER is effective in evaluating the fatigue performances of modified asphalts and can be used as a reference index of the fatigue performances of modified asphalts.

    Coupled Hydro-Mechanical Analysis of Saturated Asphalt Pavement Under Moving Traffic Loads
    Luo Su-ping Dan Han-cheng Li Liang Li Ling
    2012, 40(2):  104-111. 
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    In order to reveal the mechanism of water-induced damage to asphalt pavement,a three-layer surface course-base course-subgrade physical model is established based on the Biot´s dynamic consolidation theory,and the governing equations of the three layers are deduced for the saturated asphalt pavement under moving traffic loads. Then,by utilizing the Fourier series expansion and the Fourier transform,the semi-analytical solution and the numerical solution are obtained for multiple physical fields in the surface course. Moreover,the dry pavement is compared with the saturated one in terms of stress distribution and pore water pressure distribution,and the effect of drainage boundary condition at the surface course bottom on the dynamic response of pavement as well as the effect of the shear modulus of pavement on the pore water pressure distribution is analyzed. It is found that,for the saturated asphalt pavement,higher tensile stress and larger tensile stress area are generated under moving traffic loads and that fully drained boundary greatly affects the distributions and values of pore water pressure and pore water velocity in the surface course with high permeability. However,it only has a slight effect on the surface course with low permeability,except for the small region near the surface course bottom. It is also found that the maximum pore water pressure decreases with the increase in the shear modulus of the surface course and the base course.

    Analytical Research on Groundwater Seepage and Reinforcement Parameters of Mountain Tunnels
    Liu Fu-sheng Xu Guo-yuan Huang Wen-tong
    2012, 40(2):  112-117,123. 
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    In order to investigate the seepage pressure and discharge of mountain tunnels and reveal the effect of grouting reinforcement parameters on groundwater seepage,the distribution law of seepage pressure and the formulas of seepage discharge are deduced based on the assumption that there exists a radial stable and isotropic seepage around a circular tunnel. Then,a case study is performed. It is found that the distribution of the seepage pressure is nonlinear and that the reinforcement rim and the primary support greatly reduce the seepage pressure loading on the lining and the groundwater discharge in drainage conditions. The seepage discharge of the unlined tunnel calculated by the proposed formulas is close to the actual monitoring data,which means that the proposed method is feasible in evaluating the water inflow of similar tunnels. Moreover,according to the correlation between the reinforcement parameters and the seepage pressure as well as the seepage discharge,it can be deduced that,with the decrease
    in the permeability coefficient and with the increase in the reinforcement rim thickness,both the seepage pressure on the secondary lining and the seepage discharge decrease sharply at first,and then remain unchanged when the reinforcement parameters increase to certain values.

    Power & Electrical Engineering
    Method to Evaluate Energy-Saving Potential of Regional Main Power Grid and Its Application
    Jiang Jin-liang Liu Han-lin Zhang Yong-jun
    2012, 40(2):  118-123. 
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    In this paper,several effective means of reducing the active power loss and a method to evaluate the energy-saving potential are proposed for regional main power grid. The investigation mainly involves the optimal replacement of heavy transmission lines,the economic operation of the main transformer,the load distribution optimization,the optimal dispatching of power plants and the reactive power optimization. Then,a general idea of energysaving planning is presented,and a case study is performed on an actual regional main power grid to evaluate the energy-saving potential according to a series of flow and reactive power optimization calculation. Finally,a relevant energy-saving planning is worked out and its energy-saving effectiveness is verified.

    Identification and Correction of Abnormal Electric Load Data Based on Density Evaluation
    Chen Liang Wen Fu-shuan Tong Shu-lin
    2012, 40(2):  124-129. 
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    In general,there exist some abnormal data in the electric load database derived from the SCADA system. As these abnormal data may reduce the accuracy of the short-term load forecasting,they should be identified and corrected before their employment. In this paper,both the horizontal and the vertical continuities of electric loads are taken into consideration,and a two-dimension load data set is arranged according to the date. Then,a density evaluation-based method is presented to identify and correct the abnormal data in two dimensions,and a case study is finally performed to verify the effectiveness of the proposed method.

    Sliding-Mode Variable-Structure Control of CCM Buck Converter Based on Exact Feedback Linearization
    Le Jiang-yuan Xie Yun-xiang Ji Yu-pi Zhang Zhi
    2012, 40(2):  130-135,160. 
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    Based on the differential geometry theory and the affine nonlinear model of Buck converters,the corresponding nonlinear coordinate change matrix and nonlinear state variable feedback equations are deduced,and an exact feedback linearization model is then established. The proposed model is used to design a sliding-mode variable-structure controller by selecting suitable linear switching function and exponential reaching law. It is shown by comparison that the proposed sliding-mode variable-structure control method based on exact feedback linearization is of high dynamic response performance,excellent steady-stage error-regulating characteristics and strong robustness.

    Experimental Investigation into Measurement Accuracy of Oxide Scale in Boiler Tube Based on Magnetic Field Intensity
    Liu Ding-ping Cui Zhi-peng
    2012, 40(2):  136-141. 
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    It is easy to form oxide scale on the surface of the stainless steel used in supercritical utility boiler tube under the action of high-temperature and high-pressure steam. As the flake of the scale may jam the boiler tube and lead to overtemperature tube burst,it is necessary to detect the scale and take some measures in advance. In this paper,several detection methods of oxide scale were compared and the magnetic-field measurement accuracy
    was experimentally investigated under the conditions of different clearances between the probe and the tube,different deflection angles between the probe and the tube diameter and different relative positions of the permanent magnet and the scale. It is indicated that ( 1) when the clearance,the deflection angle and the relative position are respectively less than 1.07mm,within 25.9° and less than 26.4°,the measurement error can be controlled within 5%; ( 2 ) the clearance between the probe and the tube is the main factor that affects the measurement; and ( 3) the measured magnetic field intensity exponentially increases with the deflection angle and the relative position.

    Characteristics and Load of Non-Point Source Pollution of Urban Rainfall Runoff in Guangzhou，China
    Huang Guo-ru Nie Tie-feng
    2012, 40(2):  142-148. 
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    In this paper,a part of the drainage area in Xinhepu Community in Guangzhou city was selected as the research region and was divided into three typical types of land surfaces,namely the residential area,the road and the grass. Then,the water quality for several rainfall events on the three types of land surfaces was monitored in terms of chemical oxygen demand ( COD) ,biological oxygen demand ( BOD5 ) as well as the concentrations of total suspended solids ( TSS) ,total nitrogen ( TN) ,total phosphorus ( TP) and ammoniacal nitrogeon. Moreover,the relationship between TSS and COD was discussed,and the space-time change law of the pollutants as well as the first flush effect of the runoff was analyzed. Finally,a non-point source pollution model of rainfall runoff was established based on the storm water management model ( SWMM) and the corresponding model parameters were determined according to the observation data. The results show that ( 1) there is no obvious relationship between TSS and COD; ( 2) the first flush effect is obvious in both the residential area and the road,but is not obvious in the grass; and ( 3) the proposed model is of high accuracy and it helps to reasonably simulate the non-point source pollution load varying with the rainfall intensity,the rainfall type and the recurrence period,and provides a reference for the non-point source pollution control of urban runoff.

    Pulping Effluent Treatment with Ozone Catalyzed by Activated Carbon and Alumina Loaded or Unloaded with Titanium Dioxide
    Lei Li-rong Li You-ming Ma Li-ming
    2012, 40(2):  149-155. 
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    In order to improve the treatment efficiency of pulping effluent with ozone,activated carbon ( AC) ,alumina and their compounds TiO2 /AC and TiO2 /Al2O3 prepared via the sol-gel method were respectively used as catalysts to enhance the treatment,and the catalysts were characterized by means of SEM and XRD. The results indicate that the four kinds of catalysts all possess catalytic ability and effectively improve the removals of chemical oxygen demand ( CODCr ) and chroma of the effluent. Kinetics analysis shows that,with the catalysis of the four kinds of catalysts,the CODCr degradation process follows the apparent second-order kinetic equation; and that the TiO2 loaded on AC or Al2O3 helps to improve the reaction rate constant. Moreover,GC-MS results indicate that both the ozonation and the catalytic ozonation are effective in degrading the toxic organic compounds in the effluent such as alkyl benzenes,esters and chlorinated hydrocarbons.

    Determination of Chemical Oxygen Demand of Papermaking Wastewater via Dual-Wavelength Ultraviolet Spectroscopy
    Wang Yu-feng Chen Ke-fu Mo Li-huan Zhou Zhi-ming
    2012, 40(2):  156-160. 
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    This paper deals with the feasibility of direct COD ( chemical oxygen demand) determination for papermaking wastewater via ultraviolet spectroscopy,with two kinds of papermaking wastewater being used in the experiments. The results show that ( 1) the two kinds of papermaking wastewater both possess the maximum UV absorption wavelength of 272nm although they are of different sources; ( 2) there is a good correlation between the UV absorbance at 272nm and the COD; and ( 3) by using 546nm as a reference wavelength,the interference of suspended solids in the wastewater with the UV absorbance is eliminated and the correlation curve becomes more accurate. Moreover,as compared with the standard testing method of COD,the proposed dual-wavelength method is of high precision and accuracy that well meet the requirements of Standard HJ /T 377—2007 Water Quality On-Line Automatic Monitor of Chemical Oxygen Demand ( CODCr ) ,which means that it is feasible in the rapid determination of COD for papermaking wastewater.

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