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.

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.

Experimental Study on Pull-Out Behavior of Wedge-Grouted Rockbolt in Wind Turbine Tower Foundation

Haiyang Gao,Lianguang Wang,Xue Li,Yaosheng Zhang 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.6

To investigate the the pull-out behaviors of wedge-grouted rockbolts and grouted rockbolts in strongly weathered and moderately weathered rocks, the rockbolts with lengths of 8.0 m, 10.5 m and 13.0 m were tested under freeze–thaw cycle and cyclic load. The test result shows that the minimum anchoring length of wedge-grouted rockbolt is less than 3.0 m and of grouted rockbolt is less than 4.0 m in the strongly weathered or moderately weathered rock. The effect of the wedge head on restricting the deformation of the rockbolt is not obvious when the anchoring length is less than 6.0 m. Freeze–thaw cycle had little effect on the stiffness and deformation of the two kinds of rockbolts. The wedge-grouted rockbolts have better deformation performance than the grouted rockbolts. The bonding force between the rockbolt and the grout or the grout and the surrounding rock is greater than the tensile strength of the rockbolt. Furthermore, the calculation models of shear stress and axial strain can provide reasonable predictions for two kinds of rockbolts, and the development trends of strain and shear stress under different pullout loads were calculated.

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.

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.

Study on Preparation and Properties of PAI Materials Containing Trifluoromethyl in Side Chain

Haiyang Yang,Duxin Li,Jun Yang,Jin Wang,Shunchang Gan,Kaikai Cao,Yufeng Liu 한국고분자학회 2021 Macromolecular Research Vol.29 No.10

Polyamide-imide (PAI) materials with good heat resistance, excellent friction, wear properties, and low water absorption were prepared by acyl chloride process with diamine monomer containing trifluoromethyl in the side chain. The results showed that PAI prepared from 2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]- 4,4'-diamine without flexible hinge group had the best heat resistance, with T g as high as 302.6℃ and T d5% as 490.1℃. With the increase of the proportion of flexible hinge groups in diamine monomer, the thermal properties of PAI materials would decrease. The wear mechanism of PAI prepared from 2,2'-bis(trifluoromethyl)- [1,1'-biphenyl]-4,4'-diamine was mainly adhesive wear. With the increase of the proportion of flexible hinge groups in diamine monomer, the wear mechanism would change from abrasive wear, slight adhesive wear to severe adhesive wear. The friction coefficient and wear loss of PAI prepared by 1,4-bis(4-amino-2-trifluoromethylphenoxy) benzene were the smallest, which were 0.4706 and 3.5, respectively. PAI synthesized by diamine monomer containing trifluoromethyl had low water absorption and high water contact angle. With the increasing flexibility of monomer containing trifluoromethyl diamine, the elongation at break and tensile strength of the material increased gradually.