Seismic response and failure analyses of pile-supported transmission towers on layered ground

Haiyang Pan,Chao Li,Li Tian 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.2

Transmission towers have come to represent one of the most important infrastructures in today’s society, which may suffer severe earthquakes during their service lives. However, in the conventional seismic analyses of transmission towers, the towers are normally assumed to be fixed on the ground without considering the effect of soil-structure interaction (SSI) on the pile-supported transmission tower. This assumption may lead to inaccurate seismic performance estimations of transmission towers. In the present study, the seismic response and failure analyses of pile-supported transmission towers considering SSI are comprehensively performed based on the finite element method. Specifically, two detailed finite element (FE) models of the employed pile-supported transmission tower with and without consideration of SSI effects are established in ABAQUS analysis platform, in which SSI is simulated by the classical p-y approach. A simulation method is developed to stochastically synthesize the earthquake ground motions at different soil depths (i.e. depth-varying ground motions, DVGMs). The impacts of SSI on the dynamic characteristic, seismic response and failure modes are investigated and discussed by using the generated FE models and ground motions. Numerical results show that the vibration mode shapes of the pile-supported transmission towers with and without SSI are basically same; however, SSI can significantly affect the dynamic characteristic by altering the vibration frequencies of different modes. Neglecting the SSI and the variability of earthquake motions at different depths may cause an underestimate and overestimate on the seismic responses, respectively. Moreover, the seismic failure mode of pile-supported transmission towers is also significantly impacted by the SSI and DVGMs.

Student

Haiyang Li 한국콘텐츠학회 2016 ICCC International Digital Design Invitation Exhib Vol.2016 No.5

A Pilot Study of Clinical Evaluation and Formation Mechanism of Irritable Bowel Syndrome-like Symptoms in Inflammatory Bowel Disease Patients in Remission

( Haiyang Wang ),( Xiaojing Zhao ),( Xiufang Cui ),( Meifeng Wang ),( Chunhua Jiao ),( Jiajia Li ),( Yan Yang ),( Yi Li ),( Hongjie Zhang ) 대한소화기기능성질환·운동학회 2021 Journal of Neurogastroenterology and Motility (JNM Vol.27 No.4

Background/Aims Some inflammatory bowel disease (IBD) patients in remission suffer from irritable bowel syndrome (IBS)-like symptoms (IBD-IBS). The pathogenesis has not yet been elucidated. The study aim is to evaluate relationships among quality of life (QOL), psychological status, and visceral sensitivity, and explore the formation mechanism of IBD-IBS. Methods Forty-seven patients with Crohn’s disease in remission, 24 ulcerative colitis in remission, 26 IBS, and 20 healthy controls were included in the study. The abdominal pain, QOL, anxiety, and depression were evaluated through questionnaires. Visceral sensitivity was measured by rectal balloon distension. The serum levels of 5-hydroxytryptamine (5-HT) and nerve growth factor (NGF) were measured by enzyme-linked immunosorbent assay. The expressions of tryptase, 5-HT, NGF, and related receptors in colonic tissues were detected by immunohistochemistry and western blot. Results Prevalence of IBS-like symptoms in Crohn’s disease and ulcerative colitis patients in clinical remission was 29.8% and 50.0%, respectively. The QOL was lower, the anxiety/depression scores were higher in IBD-IBS patients than those without IBS-like symptoms. Additionally, patients with IBD-IBS existed visceral hypersensitivity. Besides, abdominal pain was associated with poor QOL, visceral hypersensitivity, anxiety, and depression in IBD-IBS patients. The number of mast cells (MCs) and expressions of 5-HT, NGF, and related receptors were higher in IBD-IBS patients than those with no such symptoms. The serum levels of 5-HT and NGF positively correlated with abdominal pain and visceral hypersensitivity. Conclusion IBD-IBS patients may have low QOL and psychological abnormalities, as wells as visceral hypersensitivity which may be related to increased 5-HT and NGF levels released from activated mast cells. (J Neurogastroenterol Motil 2021;27:612-625)

LINC00703 Acts as a Tumor Suppressor via Regulating miR-181a/KLF6 Axis in Gastric Cancer

Yang, Haiyang,Peng, Minqi,Li, Yanjiao,Zhu, Renjie,Li, Xiang,Qian, Zhengjiang The Korean Gastric Cancer Association 2019 Journal of gastric cancer Vol.19 No.4

Purpose: Long noncoding RNA 00703 (LINC00703) was found originating from a region downstream of Kruppel-like factor 6 (KLF6) gene, having 2 binding sites for miR-181a. Since KLF6 has been reported as a target of miR-181a in gastric cancer (GC), this study aims to investigate whether LINC00703 regulates the miR-181a/KLF6 axis and plays a functional role in GC pathogenesis. Materials and Methods: GC tissues, cell lines, and nude mice were included in this study. RNA binding protein immunoprecipitation (RIP) and pull-down assays were used to evaluate interaction between LINC00703 and miR-181a. Quantitative real-time polymerase chain reaction and western blot were applied for analysis of gene expression at the transcriptional and protein levels. A nude xenograft mouse model was used to determine LINC00703 function in vivo. Results: We revealed that LINC00703 competitively interacts with miR-181a to regulate KLF6. Overexpression of LINC00703 inhibited cell proliferation, migration/invasion, but promoted apoptosis in vitro, and arrested tumor growth in vivo. LINC00703 expression was found to be decreased in GC tissues, which was positively correlated with KLF6, but negatively with the miR-181a levels. Conclusions: LINC00703 may have an anti-cancer function via modulation of the miR-181a/KLF6 axis. This study also provides a new potential diagnostic marker and therapeutic target for GC treatment.

Critical seismic incidence angle of transmission tower based on shaking table tests

Li Tian,Xu Dong,Haiyang Pan,Guodong Gao,Aiqiang Xin 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.2

Transmission tower-line systems have come to represent one of the most important infrastructures in today’s society. Recent strong earthquakes revealed that transmission tower-line systems are vulnerable to earthquake excitations, and that ground motions may arrive at such structures from any direction during an earthquake event. Considering these premises, this paper presents experimental and numerical studies on the dynamic responses of a 1000 kV ultrahigh-voltage (UHV) transmission tower-line system under different seismic incidence angles. Specifically, a 1:25 reduced-scale experimental prototype model is designed and manufactured, and a series of shaking table tests are carried out. The influence of the seismic incidence angle on the dynamic structural response is discussed based on the experimental data. Additionally, the incidence angles corresponding to the maximum peak displacement of the top of the tower relative to the ground (referred to herein as the critical seismic incidence angles) are summarized. The experimental results demonstrate that seismic incidence angle has a significant influence on the dynamic responses of transmission tower-line systems. Subsequently, an approximation method is employed to orient the critical seismic incidence angle, and a corresponding finite element (FE) analysis is carried out. The angles obtained from the approximation method are compared with those acquired from the numerical simulation and shaking table tests, and good agreement is observed. The results demonstrate that the approximation method can properly predict the critical seismic incidence angles of transmission tower-line systems. This research enriches the available experimental data and provides a simple and convenient method to assess the seismic performance of UHV transmission systems.

Seismic failure analysis and safety assessment of an extremely long-span transmission tower-line system

Li Tian,Haiyang Pan,Ruisheng Ma,Xu Dong 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.71 No.3

Extremely long-span transmission tower-line system is an indispensable portion of an electricity transmission system, and its failures or collapse can impact on the entire electricity grid, affect the modern life, and cause great economic losses. It is therefore imperative to investigate the failure and safety of the transmission tower subjected to ground motions. In the present study, a detailed finite element (FE) model of a representative extremely long-span transmission tower-line system is established. A segmental damage indicator (SDI) is proposed to quantitatively assess the damage level of each segment of the transmission tower under earthquakes. Additionally, parametric studies are conducted to investigate the influence of different ground motions and incident angles on the ultimate capacity and weakest segment of the transmission tower. Finally, the collapse fragility curve in terms of the maximum SDI value and PGA is plotted for the exampled transmission tower. The results show that the proposed SDI can quantitatively assess the damage level of the segments, and thus determine the ultimate capacity and weakest segment of the transmission tower. Moreover, the different ground motions and incident angles have a significant influence on the SDI values of the transmission tower, and the collapse fragility curve is utilized to evaluate the collapse resistant capacity of the transmission tower subjected to ground motions.

Influence of Water on the Methanation Performance of Mo-Based Sulfur-Resistant Catalysts with and without Cobalt Additive

Haiyang Wang,Can Lin,Zhenhua Li,Baowei Wang,Xinbin Ma 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.1

The activities of Mo-based and Co-containing Mo-based catalysts for sulfur-resistant methanation in the presence and the absence of water are compared. When water was added to the Mo-based catalyst, its methanation activity decreased and the activity could not be recovered even after the water was removed from the system. However, for the Co-containing Mo-based catalysts, the formation of Co9S8 improved not only the methanation activity of the catalyst as active sites but also the stability of the catalyst especially in water-containing hydrogenation. The deactivation of the Mo-based catalyst in the presence of water is mainly due to reduction of the external acid sites and fewer molybdenum sulfide (MoS2) stacks. The addition of Co protects the active MoS2 phase, thereby preventing the deactivation of the catalyst in the presence of water.

Seismic response control of transmission tower-line system using SMA-based TMD

Li Tian,Mengyao Zhou,Canxing Qiu,Haiyang Pan,Kunjie Rong 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.1

This study proposes a new shape memory alloy-tuned mass damper (SMA-TMD) and investigates the effectiveness of this damper in reducing and controlling the vibrations of a transmission tower-line system under various seismic excitations. Based on a practical transmission line system and considering the geometric nonlinearity of this system, the finite element (FE) software ANSYS is used to create an FE model of the transmission tower-line system and simulate the proposed SMA-TMD. Additionally, the parameters of the SMA springs are optimized. The effectiveness of a conventional TMD and the proposed SMA-TMD in reducing and controlling the vibrations of the transmission tower-line system under seismic excitations is investigated. Moreover, the effects of the ground motion intensity and frequency ratio on the reduction ratio (η) of the SMA-TMD are studied. The vibration reduction effect of the SMA-TMD under various seismic excitations is superior to that of the conventional TMD. Changes in the ground motion intensity and frequency ratio have a significant impact on the η of the SMA-TMD. As the ground motion intensity and frequency ratio increase, the η values of the SMA-TMD first increase and then decrease. Studying the vibration reduction effects of the SMA-TMD can provide a reference for the practical engineering application of this damper.

Precursor effect on catalytic properties of Mo-based catalyst for sulfur-resistant methanation

Haiyang Wang,Xinbin Ma,Zhenhua Li,Baowei Wang,Shaodong Qin,Shouli Sun,Qi Sun 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.12

The catalytic activity of Mo-based catalysts prepared from (NH4)6Mo7O24 and (NH4)2MoS4 was com-pared in the sulfur resistant methanation process. The catalyst using oxide precursor had relatively higher activity thanthe catalyst using sulfide precursor, and the presulfidation procedure almost had no effect on the catalytic performanceof the catalyst using oxide precursor. In view of the characterization results, it could be supposed that the amorphousMoS2 was more active for sulfur-resistant methanation than the crystalline MoS2. The molybdenum sulfides and oxideswith lower valence states (Mo4+, Mo5+) could be responsible for the catalytic activity and make a possible contributionto the carbon monoxide methanation in the reaction condition.

A Fuzzy Evaluation Method of Power Transformer Insulation Health State Based on Multi-weight Fusion

Li Jifang,Zhang Haiyang,Wang Zhiyue,Feng Zhen 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

During the evaluation of transformer insulation health state, the weight of each evaluation indicator has a signifi cant infl uence on its evaluation result. To overcome the existing problem of determining the weight of evaluation indicators by a single method, this paper proposes a comprehensive weight fuzzy evaluation method based on multi-weight fusion. Firstly, the proposed method uses principal component analysis (PCA) method to determine the objective weight of each evaluation indicator based on the measured data of the power transformer. Then years of practical experiences from industry experts are introduced to subjectively study the relative importance of the evaluation indicator’s infl uences on the insulation health states and to build the relative importance of judgment matrix of relative relationship. The subjective weight of each indicator is determined by using the analytic hierarchy process. Next, the objective weight and the subjective weight are fused by using the least square method to obtain the comprehensive weight of the evaluation indicator. And insulation health values and insulation health levels of the power transformers are obtained by using fuzzy comprehensive evaluation. Finally, example analysis and comparison are carried out by using the actual operating data of the transformer. Compared with the single principal component analysis method, the correct rate of the comprehensive weighting method of the evaluation indicator proposed in this paper is improved by 5.9%, which is 10.7% higher than that of the single analytic hierarchy process. The results verify the eff ectiveness and practicability of the method proposed in this paper. The proposed method provides a scientifi c basis for the maintenance and overhaul of the transformer. It has a very important practical signifi cance for improving the stability of the power grid and ensuring the normal and orderly progress of the national economy.