Vibration based bridge scour evaluation: A data-driven method using support vector machines

Zhang, Zhiming,Sun, Chao,Li, Changbin,Sun, Mingxuan Techno-Press 2019 Structural monitoring and maintenance Vol.6 No.2

Bridge scour is one of the predominant causes of bridge failure. Current climate deterioration leads to increase of flooding frequency and severity and thus poses a higher risk of bridge scour failure than before. Recent studies have explored extensively the vibration-based scour monitoring technique by analyzing the structural modal properties before and after damage. However, the state-of-art of this area lacks a systematic approach with sufficient robustness and credibility for practical decision making. This paper attempts to develop a data-driven methodology for bridge scour monitoring using support vector machines. This study extracts features from the bridge dynamic responses based on a generic sensitivity study on the bridge's modal properties and selects the features that are significantly contributive to bridge scour detection. Results indicate that the proposed data-driven method can quantify the bridge scour damage with satisfactory accuracy for most cases. This paper provides an alternative methodology for bridge scour evaluation using the machine learning method. It has the potential to be practically applied for bridge safety assessment in case that scour happens.

Condition assessment of stay cables through enhanced time series classification using a deep learning approach

Zhiming Zhang,Jin Yan,Liangding Li,Hong Pan,Chuan-Zhi Dong 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.29 No.1

Stay cables play an essential role in cable-stayed bridges. Severe vibrations and/or harsh environment may result in cable failures. Therefore, an efficient structural health monitoring (SHM) solution for cable damage detection is necessary. This study proposes a data-driven method for immediately detecting cable damage from measured cable forces by recognizing pattern transition from the intact condition when damage occurs. In the proposed method, pattern recognition for cable damage detection is realized by time series classification (TSC) using a deep learning (DL) model, namely, the long short term memory fully convolutional network (LSTM-FCN). First, a TSC classifier is trained and validated using the cable forces (or cable force ratios) collected from intact stay cables, setting the segmented data series as input and the cable (or cable pair) ID as class labels. Subsequently, the classifier is tested using the data collected under possible damaged conditions. Finally, the cable or cable pair corresponding to the least classification accuracy is recommended as the most probable damaged cable or cable pair. A case study using measured cable forces from an in-service cable-stayed bridge shows that the cable with damage can be correctly identified using the proposed DL-TSC method. Compared with existing cable damage detection methods in the literature, the DL-TSC method requires minor data preprocessing and feature engineering and thus enables fast and convenient early detection in real applications.

Flow Velocity Deviation of Spinning Solution Under Multi-field Coupling

Zhiming Zhang,Da Hong,Xinyu Huang,Kang Liu,Qiao Xu,Zhen Chen,Qiaoling Ji,Changjin Ke 한국섬유공학회 2023 Fibers and polymers Vol.24 No.10

Rotating jet spinning uses the centrifugal force generated by the high-speed rotation of the motor to keep the spinning solution ejected from the nozzle to form nanofibers. At present, the research work on rotating jet spinning mainly involves the materials, properties and applications of fibers, parameter influence and jet trajectory, while there are few studies on the optimization of spinning core components. In this paper, by analyzing the force and flow state of spinning solution in the flow channel of spinning nozzle, it is found that the maximum velocity region of spinning solution will be offset. The reason for this phenomenon is that the spinning solution is subjected to Coriolis force in the rotating system, resulting in the secondary flow of solution. The relationship between nozzle parameters, solution parameters as well as process parameters, and the outlet velocity of solution was sought, and the structure of spinning nozzle was optimized. The factors affecting velocity offset in straight-tube nozzles and bent-tube nozzles are simulated. High-speed centrifugal spinning experiments were conducted using both unoptimized and optimized nozzles.

Effects of Surface Machining by a Lathe on Microstructure of Near Surface Layer and Corrosion Behavior of SA182 Grade 304 Stainless Steel in Simulated Primary Water

( Zhiming Zhang ),( Jianqiu Wang ),( En-hou Han ),( Wei Ke ) 한국부식방식학회(구 한국부식학회) 2019 Corrosion Science and Technology Vol.18 No.1

To find proper lathe machining parameters for SA182 Grade 304 stainless steel (SS), six kinds of samples with different machining surface states were prepared using a lathe. Surface morphologies and microstructures of near surface deformed layers on different samples were analysed. Surface morphologies and chemical composition of oxide films formed on different samples in simulated primary water with 100 μg/L O₂ at 310 ℃ were characterized. Results showed that surface roughness was mainly affected by lathe feed. Surface machining caused grain refinement at the top layer. A severely deformed layer with different thicknesses formed on all samples. In addition to high defect density caused by surface deformation, phase transformation, residual stress, and strain also affected the oxidation behaviour of SA182 Grade 304 SS in the test solution. Machining parameters used for # 4 (feed, 0.15 mm/r; back engagement, 2 mm; cutting speed, 114.86 m/min) and # 6 (feed,0.20 mm/r; back engagement, 1 mm; cutting speed, 73.01 m/min) samples were found to be proper for lathe machining of SA182 Grade 304 SS.

Identification and Characterization of EDT1 Conferring Drought Tolerance in Rice

Tao Wu,Mingxing Zhang,Hongjia Zhang,Kai Huang,Mojun Chen,Chen Chen,Xue Yang,Zhao Li,Haoyuan Chen,Zhiming Ma,Xunming Zhang,Wenzhu Jiang,Xinglin Du 한국식물학회 2019 Journal of Plant Biology Vol.62 No.1

Basic Leucine Zipper (bZIP) transcription factors(TFs) play important roles in many processes, especially inabiotic stress response in plants. In this study, we characterizeda new gene EHANCED DROUGHT TOLERANCE 1 (EDT1),member of group E of bZIP transcription factor family inrice. The EDT1 protein contains one bZIP domain, oneputative nuclear localization signal (NLS) and six conservedphosphorylation sites. The expression of EDT1 is suppressedby several abiotic stresses, such as cold, droutht, and salt. Corresponding with expression patterns, several stress-associatedcis-acting elements were found in the EDT1 promoter. Theresults of subcellular localization and transactivation abilityanalyses indicated that EDT1 was localized in the nucleusand functioned as a nuclear protein, with its transactivationactivity primarily located in N-terminal. Transgenic riceoverexpressing EDT1 showed drought tolerance that hasbeen significantly improved. Real-time PCR analysis revealedthat some stress-related genes, such as OsbZIP12, SNAC1,OsLEA3, OsbZIP16, OsbZIP10 and OsABI2 were up-regulatedin EDT1 overexpression lines. These results indicate thatEDT1 plays a positive role in drought tolerance and providesvaluable targets for breeding drought-tolerant rice cultivars.

High Power Gto Thyristors with the New Anode-Shorts Structure

Zhang Changli,Wu Jijun,Chen Zhiming 전력전자학회 1995 ICPE(ISPE)논문집 Vol.1995 No.10

An 1000-A 3000-V gate turn-off thyristor( GTO) with the ringed anode-shorts has been developed. To achieve the low on- state voltage and switching loss, the optimum device design and processing technologies are presented here. It is also confirmed that the device with ringed anode- shorts has a faster decay rates which have strongly effects on the switching loss. As a result, the improved device design gives more reliability than that of symmetri­cal GTO during the turn-off period.

POWER GTO WITH COMPENSATED RING ANODE-SHORT

Zhang Changli,Chen Zhiming,S.C.Kim,W.G.Min,J.M.Park,N.K.Kim,E.D.Kim 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

This paper gives the novel design of compensated ring anode-short for power GTO thyristor. By means of this design the power GTO of Φ63.5mm 2500A/4500V reaches more uniform turn-off compared with conventional ring shorts GTO, resulting in higher turn-off ability and low tail current/tail time.<br/>

ZnO nanowire array ultraviolet photodetectors with self-powered properties

Zhiming Bai,Xiaoqin Yan,Xiang Chen,Hanshuo Liu,Yanwei Shen,Yue Zhang 한국물리학회 2013 Current Applied Physics Vol.13 No.1

A ZnO nanowire (NW) array ultraviolet photodetector (PD) with Pt Schottky contacts has been fabricated on a glass substrate. Under UV light illumination, this PD showed a high photo-to-dark current ratio of 892 at 30 V bias. Interestingly, it was also found that this PD had a high sensitivity of 475 without external bias. This phenomenon could be explained by the asymmetric Schottky barrier height (SBH) at the two ends causing different separation efficiency of photogenerated electronehole pairs, which resulted in the formation of photocurrent. It is anticipated to have potential applications in self-powered UV detection field.

Differential expression of heat shock protein 90, 70, 60 in chicken muscles postmortem and its relationship with meat quality

Zhang, Muhan,Wang, Daoying,Geng, Zhiming,Sun, Chong,Bian, Huan,Xu, Weimin,Zhu, Yongzhi,Li, Pengpeng Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.1

Objective: The aim of this study was to investigate the expression of heat shock protein (HSP) 90, 70, and 60 in chicken muscles and their possible relationship with quality traits of meat. Methods: The breast muscles from one hundred broiler chickens were analyzed for drip loss and other quality parameters, and the levels of heat shock protein (HSP) 90, 70, and 60 were determined by immunoblots. Results: Based on the data, chicken breast muscles were segregated into low (drip loss${\leq}5%$), intermediate (5%<drip loss<9.5%) and high (drip loss${\geq}9.5$) drip loss groups. The expression of HSP90 and HSP60 were significantly lower in the high drip loss group compared to that in the low and intermediate drip loss group (p<0.05), while HSP70 was equivalent in abundance in all groups (p>0.05). Conclusion: Results of this study suggests that higher levels of HSP90 and HSP60 may be advantageous for maintenance of cell function and reduction of water loss, and they could act as potential indicator for better water holding capacity of meat.

The Deviation Characteristics of High-speed Train Running Time in Section and its Effect on Transport Capacity

Zhiming Yuan,Qi Zhang,Tao Wang,Feng Chen 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.10

Starting from the phenomenon that a large number of trains’ actual arrival & departure time deviate from specified time in train working diagram in the database of high speed railway dispatching system, the paper analyzes the defects of current train running time calculation method. Based on data mining theory, a section running time deviation calculation model for high speed railway train is proposed. Then the properties of train section running time deviation are studied in three different cases (non-stop both at the start and the end of section, stop at the end of section, and departure at the start of section) with the data from a Chinese railway bureau dispatching system, and its further influence on carrying capacity is analyzed. The results show that three deviation cases all fit Gauss distribution and the accumulative deviation time can increase the transport capacity for more than 1 million passengers per year.