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Journal of Jiangsu University(Natural Science Eidtion)
 
2012 Vol.33 Issue.1
Published 2012-01-10
Article
Article
1 Fruit recognition and positioning technology of litchi picking manipulator
XIONG Juntao, ZOU Xiangjun, CHEN Lijuan, PENG Hongxing, WU Dingzhong
The color features of mature litchi in natural environment were analyzed, and the HSV color model was chosen for threshold segmentation to remove complex background. The fuzzy C-means clustering method (FCM) was used to segment litchi fruit and peduncle. The experimental results show that the effective recognition accuracy of litchi fruit and peduncle reaches 93.3%. The maximum distance between fruit centroid and peduncle was calculated to determine litchi picking point. The color image matching method based on hue component of color image and the limiting binding method were used to realize stereo match of picking point. The positioning experimental results show that the depth value error is less than 3 cm with error rate less than 5.64%，which can meet the visual accurate position requirements of litchi picking manipulator in practical work.
2012 Vol. 33 (1): 1-5 [Abstract] ( 4035 ) [HTML 1KB] [ PDF 2596KB] ( 4198 )
6 Liquid fermentation experiment of mutagenic strainfrom Phellinus igniarius
MA Haile, YAN Jingkun, ZHU Ziping, ZHENG Huihua, YANG Xiaoming
Phellinus igniarius strain S1 mutagenized with laser and UV was chosen to study the conditions of liquid fermentation by singlefactor experiment. Based on quadratic orthogonal rotation combination design，the optimum conditions were determined as media amount of 120 mL with inoculum size of 17 mL,and fermentation temperature of 26 ℃ at rotate speed of 135 r·min-1. According to verification experiment， the actual mycelial yield was at the range of （24.47±0.80） g·L-1. The compact fermentor experiment was conducted based on the designed optimum conditions. The results show that the optimum fermentation conditions  were with stirring speed of 180 r·min-1 at temperature of 29 ℃ with air flow of 6 L·min-1.The mycelia and expolysaccharide yields can reach the range of （68.23±2.51）g and （10.23±0.35）g, respectively.
2012 Vol. 33 (1): 6-10 [Abstract] ( 1817 ) [HTML 1KB] [ PDF 1634KB] ( 1901 )
11  High-peed photography analysis on seed movement in seedchamber of clamping dibber wheel
WANG Jikui, GUO Kangquan, LV Xinmin , JIANG Bei, LI Bin
Abstract: To reveal the regularity of cotton-seed movement in circular ring seed-chamber of clamping precision seeding dibber wheel, high-speed photography analysis technique was employed to analyze the pattern of detinted cotton-seed movement. The conception of seed critical depth was proposed through observing the seed movement in different circumstance. The seeds slide as a whole on the inner side of seed-chamber without any seed going up when the seed depth is less than critical depth value. In the opposite situation， a circulation movement of seed is obtained in seed-chamber. If the seeds do not fall along the seed surface，seeds will slide down along the inner ring as a whole without circulation movement, or it will rise up along the inner ring with circulatory motion in seedchamber. Seeds with circulation movement are divided into two driving layers with a seed center zone between the two seed layers. Equipped with dibbler，rotating seeds are brought up at inner side in seedchamber, and a seed ring appears when the rotating speed of the dibbler is over 105 r·min-1.
2012 Vol. 33 (1): 11-15 [Abstract] ( 1333 ) [HTML 1KB] [ PDF 1576KB] ( 2083 )
16 Feature compression of storedgrain insects based onkernel Fisher discrimination analysis
ZHANG Hong-Tao, MAO Han-Ping, HAN Lv-Hua
Due to the characteristics of stored-grain insects with multi-species and high similarity among various species，a insects feature compression method was proposed based on kernel Fisher discrimination analysis (KFDA). According to Gaussian RBF kernel function, ten selected morphological digital insect features were analyzed by KFDA. The sample data were mapped from input space to high dimensional feature space through a nonlinear mapping function to extract. nonlinear features of raw space by Fisher discrimination analysis (FDA). According to classifier recognition ratio，KFDA was compared with FDA, principle component analysis (PCA) and kernel principle component analysis (KPCA) . Based on the first four features from KFDA，nine species of storedgrain insects in graindepot were automatically recognized by the nearest neighbor classifier with correct identification ratio of 93.33% for validation set. The results show that KFDA is sensitive to  nonlinear features of insects. The feature dimensions can be effectively reduced with high separability among species by KFDA.
2012 Vol. 33 (1): 16-20 [Abstract] ( 1425 ) [HTML 1KB] [ PDF 1347KB] ( 2004 )
21 Design of automatic vehicle anti-deflection system based on chassis dynamometer
SU Jian, MU Le, LIU Xiaolu, ZHANG Donglin, XU Guan
To solve the deflection problem of front-wheel-drive vehicle at high speed on chassis dynamo-meter, force characteristics and movement instability were studied. The axial force of blocking-wheel was selectively analyzed at different relative position between axle of blockingwheel and center of vehicle wheel after holding wheels. Based on SolidWorks platform, virtual prototype technology was applied to design the vehicle anti-deflection blocking-wheel to automatically adapt the position and diameter of vehicle wheel. The axial force on blocking-wheel was detected by sensor. The relative position between blocking-wheel axial and vehicle wheel center was identified to automatically position blocking-wheel with vehicle wheel. The vehicle deflection was prevented without slipping by blocking-wheels. The result shows that the proposed system can effectively realize pure rolling without vehicle deflection and without friction loss.
2012 Vol. 33 (1): 21-24 [Abstract] ( 1440 ) [HTML 1KB] [ PDF 2155KB] ( 1798 )
25 Acoustic-vibration optimization based on panel acoustic contribution analysis of vehicle body
WANG Erbing, ZHOU Hong, XU Gang, FENG Jun, SHI Wen
The vehicle body panels were optimized to reduce incar structural noise at low frequency. By the method of substructure mode synthesis, the structural dynamic model was set up with the boundary condition of operational vibration response for acoustic boundary element model (BEM). According to acoustic transfer vector (ATV) results, the driverrightear position was selected as acoustic response point to analyze acoustic contribution of vehicle body panels.Based on the panel contribution analysis, the key panels to incar noise were located to restrain the vibration of these crucial panels. At idle speed,the experimental validation indicates that the acoustic level of incar noise is markedly improved with the main peaks decrease of 5.70 dB and incar noise overall level decrease of  3.89 dB. Incar structural noise can be controlled by the methed of panel contribution analysis.
2012 Vol. 33 (1): 25-29 [Abstract] ( 1598 ) [HTML 1KB] [ PDF 0KB] ( 638 )
30 Forming method of tailor weld blanks based onmixed H2／H∞control
WANG Chunyan, ZHAO Wanzhong, WANG Yu, XU Xiaohong
 To solve the deficiency of constant blank holder force (BHF) method in stamping process of tailor weld blanks (TWBs), the mixed H2/H∞ control strategy for variable BHF was proposed. The control objective for the mixed H2/H∞ control was established to design control model, control algorithm and control logic. Based on the proposed model, the feedback numerical simulation was used to discuss the influence of mixed H2/H∞ control method on TWBs defect. In order to verify the simulation result, the optimal BHF curve under mixed H2/H∞ control was input to hydraulic press to realize variable BHF hydraulic press. The simulation and test results show that the inner side panel of automotive body can be successfully stamped based on the mixed H2/H∞ control strategy for variable BHF. Considering stamping trip and blank holder board position, the proposed BHF determination approach can avoid wrinkling and cracking under constant BHF with good robustness.
2012 Vol. 33 (1): 30-33 [Abstract] ( 1464 ) [HTML 1KB] [ PDF 2494KB] ( 1783 )
34 Kinetics analysis of catalytic processes for marine diesel Urea-SCR system
ZHU Yuanqing, ZHOU Song, LIU Miao, WANG Jinyu
According to the characteristics of Urea-SCR system, kinetics analysis of catalytic processes for marine diesel Urea-SCR system was carried out by computational fluid dynamics (CFD) coupled with chemical reaction kinetics. Based on 3-dimensional transient model, DeNOx rates and NH3-slips under different urea solution consumption rates, effects of fast SCR reaction on the catalytic processes and distributions of different specie concentrations were discussed. The results show that high DeNOx rate and low NH3-slip are obtained at optimal (NH2)2CO/NOx ratio of 0.475 for high load of marine diesel. The experimental DeNOx rate is consistent with calculated value with error less than 5%. DeNOx rate at high load can be further enhanced by increasing NO2/NO ratio to 1∶1 with obvious decrease of NH3slip.
2012 Vol. 33 (1): 34-38 [Abstract] ( 3360 ) [HTML 1KB] [ PDF 1800KB] ( 3723 )
39 Numerical simulation of supercavitating flow around hydrofoil
YANG Minguan, YIN Bixing, KANG Can
Based on Reynolds average method,supercavitating flow around ys930 hydrofoil were simulated by RNG k-ε model and Mixture two-phase model to obtain the relations among critical cavitation numbers of each supercavitation form, attack angle, and Reynolds number were obtained. Empirical formulas between critical cavitation numbers and Reynolds number in different conditions of attack angle were determined, and coefficient intervals were provided. The results show that the supercavitation development comprises three stages of cavity formation, two phases coexistence and fully developed phase. The critical cavitation numbers in each stage increase consistently with the increase of attack angle in a linear relationship. Because of re-entrant jet, a counterclockwise vortex makes cavity go off the suction side of the hydrofoil and falls off downstream. In different cavitation numbers, cavity falls off in different positions, leading to the change of cavity length.
2012 Vol. 33 (1): 39-43 [Abstract] ( 1573 ) [HTML 1KB] [ PDF 1511KB] ( 1893 )
44 Experiment of transcutaneous energy transmission system for heart pump
JING Teng, XU Hongxia, WANG Hao, WANG Fangqun, QIAN Kunxi
Most power supply of artificial heart was provided by wire across skin, which might cause infection and was inconvenient to patient daily life. To solve this problem, based on electromagnetic induction, a transcutaneous energy transmission system was designed to transfer power by non-contact coupling. Wireless energy transmission efficiency of artificial heart implemented in human body was realized by the proposed system. The effects of transformer secondary windings coil, switching frequency and transformer air gap size on the system were investigated by experiments. The results show that the transformer has best performance with primary coil of 30 circles and secondary coils of 60 circles. When frequency reaches 40 kHz, the system has maximum transmission efficiency. The transmission efficiency decreases with the increase of gap size. The efficiency is 60％ to 80％ in the air gap range of 0-3 mm, while it decreases obviously for the air gap over 3 mm.
2012 Vol. 33 (1): 44-48 [Abstract] ( 1543 ) [HTML 1KB] [ PDF 1978KB] ( 2301 )
49 Experiment on heat transfer characteristics of single loop pulsating heat pipe
SU Lei, ZHANG Hong, DING Leijiang, DING Rui
The heat transfer characteristics of steady state for single loop red copper-water pulsating heat pipe were investigated under the conditions of air-cooling and constant heating power. The characteristics of wall temperature distribution along tube length, and the variety rules of condenser and evaporator temperature rise or drop, heat transfer temperature difference and heat transfer thermal resistance with heat input power were discussed. The effects of charging ratio and pipe diameter on heat transfer performance were also analyzed. The results show that the heat transfer temperature difference and the average temperature of condenser and evaporator increase with the increasing of heat transfer power, while thermal resistance decreases. The effects of pipe diameter, charging ratio and heat power on thermal resistance are obvious for small heat input power. Reducing filling ratio or increasing internal diameter and heat power can reduce thermal resistance of heat pipe significantly. However, pipe
2012 Vol. 33 (1): 49-54 [Abstract] ( 1673 ) [HTML 1KB] [ PDF 1873KB] ( 2368 )
55 Novel blind estimation method for OFDM over-sampling rate
LIU Mingqian, LI Bingbing, TANG Ningjie
To solve the poor performance of traditional blind orthogonal frequency division multiplexing(OFDM) oversampling rate estimation method at low signal to noise ratio(SNR) and multipath channel conditions, a novel blind OFDM oversampling rate estimation method was proposed based on the spectrum characteristics of OFDM baseband sampling signals. The improved moving covariance method was adopted to estimate the carrier frequency, and to establish the power spectrum of received signal by Welch method. An optimal cosine rolloff filter was designed with an optimal rolloff factor to make the cutoff frequency of the designed filter approach that of sampling signal. The oversampling rate was estimated based on the spectrum characteristics of oversampling signals to realize blind estimation for different OFDM signals oversampling rate. The simulation results show that the mean square error(MSE) of OFDM signals oversampling rate is less than 0.2 at the conditions of -2 dB SNR and multipath channel. The proposed method has good estimation performance at the conditions of low SNR and multipath channel without any prior knowledge.
2012 Vol. 33 (1): 55-59 [Abstract] ( 2691 ) [HTML 1KB] [ PDF 1747KB] ( 3752 )
60 Full decoupling control of bearingless switched reluctance motor based on support vector machine inverse system
ZHOU Yunhong, SUN Yukun, HUANG Yonghong
In view of the magnetic saturation, non-linearity and coupling, it was very difficult to establish mathematic model and realize decoupling for bearingless switched reluctance motor (BSRM). Based on least squares support vector machine (LS-SVM), a novel mathematic model involving magnetic saturation was proposed to establish inverse system  to decouple radial suspending forces and torque. The closedloop decoupling control experiments were conducted on dSPACE platform to verify the decoupling ability and the robustness with time-variant parameters. The results show that the proposed method has advantages of both nonlinear approximation ability of LSSVM and decoupling linearization character of inverse system method.  The constructed LS-SVM inverse system decoupling controller has strong autoadaptive performance and robustness. The unsuitability for magnetic-saturated condition of existing models and corresponding decoupling methods which are based on nonsaturation hypothesis can be solved.
2012 Vol. 33 (1): 60-64 [Abstract] ( 1881 ) [HTML 1KB] [ PDF 1607KB] ( 2057 )
65 Multi-robot formation control and stability analysis for limited communication
JIANG Limei, ZHANG Rubo
To eliminate the influence of limited communication on formation control for multi-robot system, a distributed formation control algorithm based on communication delay was proposed by consensus theory. A formation graph was employed to describe the network topology of robots, and some related matrixes were introduced to represent the formation graph form a desired formation condition by matrix control theories. According to Lyapunov stability theorem, delayindependent and delaydependent stable conditions were obtained respectively in the form of linear matrix inequality (LMI). The multirobot system was verified to converge to the desired geometry formation and velocity asymptotically by the proposed algorithm. Simulations of multirobot formation were performed to verify the effectiveness of formation control strategy and the correctness of conclusions. The results show that the multirobot system can form the desired formation by the proposed algorithm under stable condition.
2012 Vol. 33 (1): 65-70 [Abstract] ( 1668 ) [HTML 1KB] [ PDF 1899KB] ( 2570 )
71 Noise source impedance modeling and measurement error analysis based on insertion loss method
SHI Guosheng, ZHAO Yang, YAN Wei, DONG Yinghua, ZHU Zhiyi
In order to solve the impedance matching problem for conducted EMI filter designing of artificial mains network (AMN) impedance, noise source impedance, load impedance and EMI filter impedance, the error theoretical model and equivalent circuits of insertion loss (IL) method were established. The measurement accuracy and system error of series and parallel IL methods were analyzed to provide improved test condition and methods. Series IL method was used when the measured impedance was much larger than load impedance. Parallel IL method was utilized when the measured impedance was much smaller than load impedance. The load impedance was altered when the measured impedance approximately equaled to load impedance. Theoretical analysis and experimental results show that the proposed method can extract EMI noise impedance effectively in certain range, where it can also realize the maximum impedance adapter between noise impedance and EMI filter. The proposed method has good validity for EMI filter design and conducted EMI noise suppression.
2012 Vol. 33 (1): 71-76 [Abstract] ( 1453 ) [HTML 1KB] [ PDF 2258KB] ( 2330 )
77 Automatic Web services composition based on improved HTN planning
XIAO Yihong, ZHOU Xianzhong, ZHU Liang, SU Zhenglian, LU Xiaoming
In order to solve complex problems by automatical compositing of several Web services for no exact single one, an ontology language of web services called OWL-S was applied in semantic encapsulation of Web services with an AI planning method called hierarchical task network (HTN) as technical means. Based on the similarity analysis of OWL-S and HTN, the operator and method definitions of HTN were redefined, and the conventional HTN planning algorithm was extended to semantic HTN. Based on a set of OWL-S descriptions and improved HTN planning, a planner frame for supporting services composition was introduced to establish experimental system. The results of case study show that automatic Web services composition with domain ontology can be availably realized by the improved HTN planning algorithm.
2012 Vol. 33 (1): 77-82 [Abstract] ( 1636 ) [HTML 1KB] [ PDF 2447KB] ( 2244 )
83 Numerical modeling of laser-induced picosecond ultrasound in micro-nano thin films
XU Boqiang, ZHANG Ziguo, XU Chenguang, XU Guidong, YANG Xiaoping
Based on two temperature model(TTM) and thermalelastic theory, finite element numerical model of femtosecond laser-induced picosecond ultrasound was applied in investigating laser interaction of Al/Si3N4 and Al/Si3N4/Si multilayer thin films. The temperature fields of electron and lattice in Al film were caculated by the finite element method to analyze the surface displacement response and strain in  thin films. The computational result from TTM theory was compared with that from classical fourier heat transfer theory. The comparison indicates that TTM theory is suitable for picosecond ultrasonic investigation. According to numerical analysis, the strain amplitude is small with wide waveform. The peaks of displacement response spectrum on Al surface are induced by ultrasound reflection within the interface of films.
2012 Vol. 33 (1): 83-87 [Abstract] ( 1476 ) [HTML 1KB] [ PDF 1964KB] ( 2348 )
88 DC／AC test of electric property for silicone rubber matrix conductive composites
LIAO Bo, ZHOU Guoqing, LIU Zhuodian
The voltage-current characteristics of carbon and carbon fiber reinforced silicone rubbermatrix conductive composites were tested under DC or AC voltage. The result shows that the conductive compo-sites have non-ohmic behavior with nonlinear relationship of voltage and current. The current output is not affected for small change of AC excitation frequency, but decreases significantly with the frequency increase for large change. The sample impedance decreases with the increase of frequency in different AC frequency test. Tunnel conductivity (capacitance impedance) exists simultaneously with lap joint/contacts conductivity (resistance impedance) in the conductive composites, and the tunnel current is main factor for above phenomenon. The results show that it is important to know the excitation power model during electric property test of conductive composites.
2012 Vol. 33 (1): 88-91 [Abstract] ( 1908 ) [HTML 1KB] [ PDF 1530KB] ( 2829 )
92 Adhesion and friction properties of GeSbTe phase change films prepared by magnetron sputtering
FU Yongzhong, CHENG Guanggui, WANG Quan
The GeSbTe films were prepared with different RF magnetron sputtering time at  room temperature. The surface topography, thickness, adhesion and friction properties of films were investigated by atomic force microscopy(AFM), Talystep and TriboIndenter nanomechanical test system. The results show that the surface roughness decreases with the increasing of sputtering time, while the thickness and quality increase. The tip diameter(TD), relative humidity(RH),normal load(NL) applied the tip are important factors on adhesion and friction properties of films. The adhesion and friction between the tip and GeSbTe films can be reduced obviously by the decreasing of TD and RH. The frictional performance can be improved by enhancing surface quality and choosing appropriate NL on the tip.
2012 Vol. 33 (1): 92-95 [Abstract] ( 1409 ) [HTML 1KB] [ PDF 1597KB] ( 2274 )
96 Laser bending experiment and mechanical properties analysis of C194 copper alloy sheet
HUANG Shu, ZHOU Jianzhong, HU Lingling, YANG Xiaodong
The laser bending test of C194 copper alloy was conducted by pulsed lasers to investigate the effect of laser parameters on bending angle. The tensile strength, load displacement curve, microhardness, surface topography and surface roughness before bending were compared with those after bending. The results indicate that the bending angle increases firstly and then decreases with the increase of laser power and defocusing distance. The bending angle decreases with the increases of scanning velocity,while increases with the increase of scanning times. The relationship between scanning times and bending angle shows approximate linearity for low scanning cycle. The tensile strength is decreased by the increase of laser power, while increased by refining grain at low power condition. There is no obvious stiffening in bended specimen with average surface hardness increasing by 3.3%. The surface roughness and section roughness in x, y direction of sheet metal are increased at different degree by the uneven temperature field induced from laser bending process.
2012 Vol. 33 (1): 96-101 [Abstract] ( 1906 ) [HTML 1KB] [ PDF 2362KB] ( 2220 )
102 Concentration recombinant of α-acetolactate decarboxylase with ultrafiltration membrane and enzymatic cleaning
MENG Jianzong, Qi-Xianghui, LI Cong, WU Huade, NONG Cuifei
α-Acetolactate decarboxylase was concentrated from Bacillus subtilis with polyethersulfone(PES) ultrafiltration membrane.The effects of temperature and pH value on membrane flux were investigated to determine the recovery conditions of chemical and enzymatic cleaning of ultrafiltration membrane. The result show that membrane flux is affected strongly by pH value of enzyme solution. After 10fold concentration, the permeate flux at pH of 5.1 is only 20.3% of that at pH of 7.1.The recovery of αacetolactate decarboxylase can reach 89.6% at the optimum ultrafiltration conditions for pressure of 0.1 MPa, temperature of 35 ℃, and pH value of 7.1. During enzymatic cleaning, the high neutral protease activity of 1.25×104 U·L-1 can result in membrane refouling. The best cleaning effect can be achieved by combining neutral protease of 1.25×104 U·L-1 and sodium hypochlorite of 1% with flux recovery rate of 97.0%.
2012 Vol. 33 (1): 102-105 [Abstract] ( 2056 ) [HTML 1KB] [ PDF 1796KB] ( 1811 )
106 Synthesis of mesoporous Zr-MCM-41 and its catalytic performance for tert-butylation of phenol
JIANG Tingshun, QI Liwen, WU Duolin, ZHOU Xuping, ZHAO Qian
Zr-MCM-41 mesoporous molecular sieves with different Si/Zr molar ratios were hydrothermally synthesized and characterized by XRD, TEM and N2 physical adsorption. SO2-4/Zr-MCM-41 catalysts were prepared by wet impregnation method with H2SO4 solution. The results reveal that the synthesized MCM-41 samples show typical mesoporous structure, and the specific surface area and pore volume of samples decrease gradually with the decrease of Si/Zr molar ratio.When the Si/Zr molar ratio equals to 5, the mesoporous framework of sample is disorder without any hexagonal mesoporous structure. The SO2-4/Zr-MCM-41 catalyst exhibits high catalytic activity for alkylation reaction of phenol with increased 4-tert-butyl-phenol selectivity and decreased 2,4di-t-butyl phenol selectivity for enhanced temperature. Under optimum catalytic condition with tertbutyl alcohol to phenol molar ratio of 2, WHSV of 2 h-1 and reaction time of 2 h at 140 ℃, phenol conversion can reach 82.9%.
2012 Vol. 33 (1): 106-109 [Abstract] ( 1835 ) [HTML 1KB] [ PDF 1731KB] ( 1732 )
110 Experimental and numerical study of thick soft ground improved by vacuum-surcharge preloading
WANG Zhiqiang, TANG Tongzhi, HUANG Kangli, MING Jingping, LIU Jiacai
To improve the deep strengthening effect, vacuum surcharge preloading method was applied in expressway to change the form of vertical drainage channel. 150 mm width prefabricated vertical drain(PVD) and 100 mm modified bag sandwell were used respectively as vertical drainage body. The bag sandwell was inserted with 10 m long and 8 mm in diameter plastic small tube. The strengthening efficiencies of the two new drainage bodies for deep soft soil were verified by comparison experiments. The results show that attenuation of vacuum pressure is small in 150 mm width PVD with large settlement in preloading period, while the vacuum pressure transmit depth can be increased in 8 mm diameter plastic tube. Based on modified Cambridge model, the soil rheology and reload deformation characteristics after unload were considered to improve the constitutive soil model, and to propose corresponding finite element calculate method.The actual example validation indicates that the data fine accuracy and regularity of calculate values are consistent with those of test values.
2012 Vol. 33 (1): 110-114 [Abstract] ( 1425 ) [HTML 1KB] [ PDF 1609KB] ( 2393 )
115 Fatigue damage model of prestressed concrete beamssuffered freeze-thawing
LIU Ronggui, ZHANG Yiduo, CHEN Yu, LIU Tao
In order to inverstigate the rigidity deterioration regulation of the accumulative fatigue damage under freeze-thaw enviorment, a fatigue experiment of seven prestressed concrete beams was conducted for different freezethawing times. The experiment results indicate that freezethawing effect can aggravate the deflection development of test beams in fatigue experiment. The remaining rigidity of test beams shows a course of a three-stage deterioration characteristic, and displays a linear deterioration during the second stage with 66% initial rigidity at fracture. A model was proposed to describe the relation between accumulative damage of D and cycling life ratio of n/Nf. The freezethawing effect on accumulative damage was considered to provide valuable reference in fatigue life prediction of prestressed concrete beams in cold region.
2012 Vol. 33 (1): 115-119 [Abstract] ( 1473 ) [HTML 1KB] [ PDF 1951KB] ( 1798 )
120 Carbon footprint estimation of transportation industry in China
LUO Xi, ZHANG Shaoliang, BIAN Xiaohong, ZHANG Weiwei
According to the data of energy consumption and transport turnover from 2004 to 2008 in China, carbon footprint of transportation industry was estimated through carbon footprint model. The results show that total carbon footprint from transportation energy consumption in China is growing continuously, and increases from 3.702 534×108 t in 2004 to 4.884 943×108 t in 2008 with an average annual increase of 7.17%.The direct carbon footprint from terminal fossil energy use in 5 years accounts for 89.06%. Carbon footprint from diesel consumption accounts for the largest proportion in total carbon footprint with 46.65%. The second proportion of carbon footprint is from gasoline consumption with 17.85%, and shows a similar rising trend from diesel consumption to that year after year. Per unit conversion turnover carbon footprint shows an obvious declining trend, and drops from 485.72 kg·(104 t·km)-1 in 2004 to 408.45 kg·(104 t·km)-1 in 2008 with average annual decline of 4.24%.
2012 Vol. 33 (1): 120-124 [Abstract] ( 1714 ) [HTML 1KB] [ PDF 1622KB] ( 3341 )
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