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Crack identification method of highway tunnel based on image processing

Journal of Traffic and Transportation Engineering(English Edition) 2023年第3期10卷 469-484页

作者： Guansheng Yin Jianguo gao Jianmin Gao Chang Li Mingzhu Jin Minghui Shi Hongliang Tuo Pengfei Wei School of Sciences Chang'an UniversityXi'an 710064China School of Transportation Science and Engineering Civil Aviation University of ChinaTianjin 300300China School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

In this paper,the images of tunnel surface are obtained by tunnel lining rapid inspection system,and tunnel crack forest dataset(TCFD)is established.The disaster characteristics of tunnel cracks are analyzed and summarized.Solutions of tunnel crack segmentation(TCS)method are developed for the detection and recognition of cracks on tunnel lining.According to the image features of the tunnel lining and the optical principal of detection equipment,effective image pre-processing steps are carried out before crack extraction.The tunnel image of TCFD is divided into appropriate number of blocks to magnify the local features of tunnel cracks.Local threshold segmentation method is used to traverse the blocks successively,and the first target block with crack is obtained.The seed in the target block were obtained by adaptive localization method and mapped to the whole image.Region growing is performed through crack seed until complete tunnel crack is extracted.The results show that the precision,recall rate and F-measure of tunnel cracks under the TCS method can reach 92.58%,93.07%and 92.82%without strong interference.According to the binary images processed by TCS method,the projection images of different types of tunnel cracks and their respective laws are obtained.Furthermore,the TCS method is implemented and deployed as a GUI software application.

关键词： Tunnel engineering Crack identification Image binarization Tunnel crack Region growing Contrast limited adaptive histogram equalization

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A new method to forecast multi-time scale load of natural gas based on augmentation data-machine learning model

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Chinese Journal of Chemical Engineering 2022年第8期35卷 166-175页

作者： Denglong Ma Ruitao Wu Zekang Li Kang Cen Jianmin Gao Zaoxiao Zhang School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Civil Engineering and Architecture Southwest Petroleum UniversityChengdu 610500China School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710049China

Gas load forecasting is important for the economic and reliable operation of the city gas transmission and distribution system.In this paper,a nonlinear autoregressive model(NARX)with exogenous inputs,support vector machine(SVM),Gaussian process regression(GPR)and ensemble tree model(ETREE)were used to predict and compare the gas load based on the gas load data in a certain region for past 3 years.The results showed that the prediction errors for most of days were higher than 10%.Further,simulation data were generated by considering the gas load variation trend,which was then combined with historical data to form the augmentation data set to train the model.The test results indicated that the prediction error of daily gas load in one year reduced to below 7%with a machine learning prediction method based on augmentation data.In addition,the model based on augmentation data set still performed better than original data in predicting the monthly gas load in last year as well as daily gas load in last month and week.Therefore,the method based on augmentation data proposed in this paper is a potentially good tool to forecast natural gas load.

关键词： Natural gas Machine learning Prediction Neural network Augmentation data

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Gas leakage recognition for CO2 geological sequestration based on the time series neural network

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Chinese Journal of Chemical Engineering 2020年第9期28卷 2343-2357页

作者： Denglong Ma Jianmin Gao Zhiyong gao Hongquan Jiang Zaoxiao Zhang Juntai Xie School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049China School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an 710049China

The leakage of stored and transported CO2 is a risk for geological sequestration technology. One of the most challenging problems is to recognize and determine CO2 leakage signal in the complex atmosphere background. In this work, a time series model was proposed to forecast the atmospheric CO2 variation and the approximation error of the model was utilized to recognize the leakage. First, the fitting neural network trained with recently past CO2 data was applied to predict the daily atmospheric CO2. Further, the recurrent nonlinear autoregressive with exogenous input(NARX) model was adopted to get more accurate prediction. Compared with fitting neural network, the approximation errors of NARX have a clearer baseline, and the abnormal leakage signal can be seized more easily even in small release cases. Hence, the fitting approximation of time series prediction model is a potential excellent method to capture atmospheric abnormal signal for CO2 storage and transportation technologies.

关键词： Leakage identification Process safety Gas leakage Monitoring carbon sequestration CO2 storage

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Acoustic Nonlinearity Parameters Due to Microstructural Defects

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Acta Mechanica Solida Sinica 2018年第5期31卷 525-534页

作者： Xiang gao jianmin Qu Department of Mechanical Engineering Tufts University Medford MA 02155 USA

This study presents a general approach to derive the acoustic nonlinearity parameters induced by various types of dislocation configurations including dislocation strings （monopoles）, dislocation dipoles, dislocation pileups and extended dislocations. It is found that expressions of the acoustic nonlinearity parameter induced by such a variety of dislocation con- figurations share a common mathematical form. They are all scaled with （Lch/b）n, where Lch is a characteristic length of the dislocation configuration, b is the magnitude of the Burgers vector, and n is either 3 or 4. Semiquantitative analysis is presented to compare the magnitudes of the acoustic nonlinearity parameters among different types of dislocation configurations.

关键词： Nonlinear ultrasound Nondestructive evaluation Acoustic nonlinearity parameter Microstructural defects Dislocations

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Effect of aging treatment on the precipitation transformation and age hardening of Mg-Gd-Y-Zn-Zr alloy

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Journal of Magnesium and Alloys 2023年第12期11卷 4628-4643页

作者： Mu Meng Honglei Zhang Zhi gao Genxing Lei jianmin Yu College of Materials Science and Engineering North University of ChinaXueyuan Road 3Taiyuan 030051China Beijing North Vehicle Group Corporation ZhuJiaFen 5th LiBeijing 100072China

In this study, the precipitation transformation and age hardening of solution-treated Mg-9Gd-4Y-2Zn-0.5Zr(wt.%) alloy were investigated at different aging treatment parameters. The precipitation sequences of the alloy aged at 200℃, 250℃ and 300℃ are β’’(DO19) → β’(BCO) → β(FCC), β’’(DO19) → β’(BCO) → β_(1)(FCC) → β(FCC) and β(FCC), respectively. The streaks sequences of the alloy aged at 200℃, 250℃ and 300℃ are SF, SF → 14H-LPSO and SF → 14H-LPSO, respectively. For the alloy aged at 200℃ and 250℃, the increase in hardness with increasing aging time is contributed from the increase in precipitate volume fraction and the transformation from β’’ to β’ phase with basal → prismatic and spherical → spindle-like precipitate changes. The decrease in hardness after the peak-aging stage is attributed to the appearance of micro-sized β precipitates. Because of the smaller size of precipitates and the triangular arrangement of β’ precipitate, the hardness of the alloy aged at 200℃ is higher than that aged at 250℃. For the alloy aged at 300℃, the appearance of only micro-sized β precipitate and its coarsening with increasing aging time leads to the lowest hardness and an overall decrease in hardness with the aging time.

关键词： Mg-Gd-Y-Zn-Zr alloy Aging treatment Precipitation transformation Age hardening

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Boosting the direct conversion of NH4HCO3 electrolyte to syngas on Ag/Zn zeolitic imidazolate framework derived nitrogen-carbon skeleton

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化学科学与工程前沿:英文版 2023年第9期17卷 1196-1207页

作者： Huiyi Li Jianmin Gao Jingjing Shan Qian Du Yu Zhang Xin Guo Shaohua Wu Zhijiang Wang Institute of Combustion Engineering School of Energy Science and EngineeringHarbin Institute of TechnologyHarbin150001China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001China Harbin Bolier Co. Ltd.Harbin150040China Department of Environmental Engineering Shanxi UniversityTaiyuan030006China

The electrochemical reduction of NH4HCO3 to syngas can bypass the high energy consumption of high-purity CO_(2)release and compression after the ammonia-based CO_(2)capture process.This technology has broad prospects in industrial applications and carbon neutrality.A zeolitic imidazolate framework-8 precursor was introduced with different Ag contents via colloid chemical synthesis.This material was carbonized at 1000℃to obtain AgZn zeolitic imidazolate framework derived nitrogen carbon catalysts,which were used for the first time for boosting the direct conversion of NH4HCO3 electrolyte to syngas.The AgZn zeolitic imidazolate framework derived nitrogen carbon catalyst with a Ag/Zn ratio of 0.5:1 achieved the highest CO Faradaic efficiency of 52.0%with a current density of 1.15 mA·cm^(−2)at−0.5 V,a H2/CO ratio of 1-2(−0.5 to−0.7 V),and a stable catalytic activity of more than 6 h.Its activity is comparable to that of the CO_(2)-saturated NH4HCO3 electrolyte.The highly discrete Ag-N_(x)and Zn-N_(x)nodes may have combined catalytic effects in the catalysts synthesized by appropriate Ag doping and sufficient carbonization.These nodes could increase active sites of catalysts,which is conducive to the transport and adsorption of reactant CO_(2)and the stability of*COOH intermediate,thus can improve the selectivity and catalytic activity of CO.

关键词： Ag catalyst zeolitic imidazolate framework CO_(2)electroreduction ammonium bicarbonate electrolyte syngas

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Design and experiment of low-frequency ultrasonic nozzle integrating air-assistant system and acoustic levitation mechanism

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International Journal of Agricultural and Biological Engineering 2020年第6期13卷 25-33页

作者： Jianmin Gao Mazhar Hussian Tunio Yiming Chen Rui He School of Agricultural Engineering Jiangsu UniversityZhenjiang 212013China

Ultrasonic atomization nozzles are generally divided into two categories:high frequency and low-frequency ultrasonic atomization nozzles.Compared with high-frequency ultrasonic atomization nozzles(working frequencies>1 MHz),low-frequency ultrasonic atomization nozzles are not sensitive to clarity,temperature and viscosity of the liquid.However,they can control atomization quantity precisely,but the sizes of droplets generated by them are relatively large.In aeroponics cultivation,and precision welding,in such both cases,precise spraying control and tiny droplet sizes are expected.Therefore,how to decrease droplet size using low-frequency ultrasonic atomization nozzles is a valuable issue.In this paper a 60 kHz low-frequency ultrasonic atomization nozzle integrating air-assistant system and acoustic levitation mechanism was proposed and designed.Furthermore,the design was verified by FEA(Finite Element Analyzes)and impedance analyzer PV70A,and the verified results indicated relative design error was 0.49%.Driving voltage,spout angle,air pressure and levitating ball were taken as influential factors in the experimental protocol to the character in spray properties of this designed nozzle.A laser particle size analyzer was used to measure droplet sizes.Experiment results indicated that:the diameters of droplets generated by this nozzle at driving voltage 46 V were smaller than those at 40 V driving voltage;Both the assistant air and levitation mechanism could effectively change the diameters and uniformity of droplets;The minimum values of D10,D50,and D90(D10,D50 and D90 were mean diameters when cumulative percentages of the samples’diameter were 10%,50%and 90%,respectively)were 23.06μm,31.14μm and 41.38μm,respectively.However,all those minimum values were presented at the same run(spout angle 0°,air pressure 0.05 MPa,having levitated ball,driving voltage 46 V);Levitating ball above the atomization surface would make droplet sizes more uniform and tinier.More importantly,the famous Lang equation which assumes that d

关键词： nozzle ultrasonic atomization droplet sonic levitation air-assistant

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Experimental study of ultrasonic atomizer effects on values of EC and pH of nutrient solution

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International Journal of Agricultural and Biological Engineering 2018年第5期11卷 59-64页

作者： Imran Ali Lakhiar Xingda Liu Guanqun Wang Jianmin Gao School of Agricultural Equipment Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

The objectives of this research were to reveal how main working parameters of ultrasonic atomizers would influence key properties of the atomized nutrient solution in an aeroponics system.The Yamazaki tomato nutrient solution was selected as a nutrient example.Uniform design(UD)method U_(12)(12^(2)×13)was adopted to arrange the test.In this test,spraying time and interval time were taken as quantitative factors with 12 levels(10,20,30,40,50,60,70,80,90,100,110,and 120 min,respectively),and ultrasonic atomizer frequency was taken as qualitative factor with 3 conditions(28 kHz,107 kHz,1.7 MHz).Based on test data,two regression formulations used to predict the values ofΔEC,andΔpH of atomized Yamazaki tomato nutrient solution was established and inspected.The spraying interval time of ultrasonic atomizers had no significant effect on EC and pH of the atomized Yamazaki tomato nutrient solution;the ultrasonic atomizer frequency was more effective than spraying time on the values of EC and pH;the values of EC and pH became maximum at(f_(3),T_(1))=(1.7 MHz,120 min)and minimum at(f_(1),T_(1))=(28 kHz,10 min).It was concluded that the effect of high-frequency(1.7 MHz)ultrasonic atomizer on EC and pH of the Yamazaki tomato nutrient solution was beyond the standard value for tomato growth.Therefore,the high-frequency(1.7 MHz)ultrasonic atomizer is not suitable for aeroponics cultivation when using the Yamazaki tomato nutrient solution as aeroponics nutrient solution.

关键词： aeroponics tomato nutrient solution EC pH ultrasonic atomizer frequency spray time interval time uniform design

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Residential PV capacity estimation and power disaggregation using net metering measurements

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Global Energy Interconnection 2022年第6期5卷 590-603页

作者： Bo Liu jianmin Tian Wenpeng Luan Yi gao Xiaohui Wang Shuai Luo School of Electrical and Information Engineering Tianjin UniversityTianjin 300072P.R.China Economic and Technical Research Institute State Grid Tianjin Electric Power CompanyTianjin 300171P.R.China Artificial Intelligence Application Department China Electric Power Research InstituteBeijing 100089P.R.China

As the intermittency and uncertainty of photovoltaic(PV)power generation poses considerable challenges to the power system operation,accurate PV generation estimates are critical for the distribution operation,maintenance,and demand response program implementation because of the increasing usage of distributed PVs.Currently,most residential PVs are installed behind the meter,with only the net load available to the utilities.Therefore,a method for disaggregating the residential PV generation from the net load data is needed to enhance the grid-edge observability.In this study,an unsupervised PV capacity estimation method based on net metering data is proposed,for estimating the PV capacity in the customer’s premise based on the distribution characteristics of nocturnal and diurnal net load extremes.Then,the PV generation disaggregation method is presented.Based on the analysis of the correlation between the nocturnal and diurnal actual loads and the correlation between the PV capacity and their actual PV generation,the PV generation of customers is estimated by applying linear fitting of multiple typical solar exemplars and then disaggregating them into hourly-resolution power profiles.Finally,the anomalies of disaggregated PV power are calibrated and corrected using the estimated capacity.Experiment results on a real-world hourly dataset involving 260 customers show that the proposed PV capacity estimation method achieves good accuracy because of the advantages of robustness and low complexity.Compared with the state-of-the-art PV disaggregation algorithm,the proposed method exhibits a reduction of over 15%for the mean absolute percentage error and over 20%for the root mean square error.

关键词： Behind-the-meter Residential photovoltaic Capacity estimation Power disaggregation Net metering

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High-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Ce_(2)O_(7):A potential thermal barrier material with improved thermo-physical properties

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Journal of Advanced Ceramics 2022年第4期11卷 615-628页

作者： Yun XUE Xiaoqin ZHAO Yulong AN Yijing WANG Meizhen gao Huidi ZHOU jianmin CHEN Key Laboratory of Science and Technology on Wear and Protection of Materials Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Key Lab for Magnetism and Magnetic Materials of MOE School of Physical Science and TechnologyLanzhou UniversityLanzhou 730000China

High-entropy oxides(HEOs)are widely researched as potential materials for thermal barrier coatings(TBCs).However,the relatively low thermal expansion coefficient(TEC)of those materials severely restricts their practical application.In order to improve the poor thermal expansion property and further reduce the thermal conductivity,high-entropy(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Ce_(2)O_(7) is designed and synthesized in this work.The as-prepared multicomponent material is formed in a simple disordered fluorite structure due to the high-entropy stabilization effect.Notably,it exhibits a much higher TEC of approximately 12.0×10^(−6) K^(−1) compared with those of other high-entropy oxides reported in the field of TBCs.Besides,it presents prominent thermal insulation behavior with a low intrinsic thermal conductivity of 0.92 W·m^(−1)·K^(−1) at 1400℃,which can be explained by the existence of high concentration oxygen vacancies and highly disordered arrangement of multicomponent cations in the unique high-entropy configuration.Through high-temperature in-situ X-ray diffraction(XRD)measurement,this material shows excellent phase stability up to 1400℃.Benefiting from the solid solution strengthening effect,it shows a higher hardness of 8.72 GPa than the corresponding single component compounds.The superior thermo-physical performance above enables(La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Ce_(2)O_(7) a promising TBC material.

关键词： high-entropy oxides(HEOs) (La_(0.2)Nd_(0.2)Sm_(0.2)Eu_(0.2)Gd_(0.2))_(2)Ce_(2)O_(7) defective fluorite structure thermal expansion coefficient(TEC) thermal conductivity thermal barrier coating(TBC)

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