Mechanical behavior of coiled tubing over wellhead and analysis of its effect on downhole buckling

Le Zhao,Mingzhong Gao,Cunbao Li,Linyun Xian 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.2

This study build finite element analysis (FEA) models describing the bending events of coiled tubing (CT) at the wellhead and trips into the hole, accurately provide the state of stress and strain while the CT is in service. The bending moment and axial force history curves are used as loads and boundary conditions in the diametrical growth models to ensure consistency with the actual working conditions in field operations. The simulation diametrical growth results in this study are more accurate and reasonable. Analysis the factors influencing fatigue and diametrical growth shows that the internal pressure has a first-order influence on fatigue, followed by the radius of the guide arch, reel and the CT diameter. As the number of trip cycles increase, fatigue damage, residual stress and strain cumulatively increase, until CT failure occurs. Significant residual stresses remain in the CT cross-section, and the CT exhibits a residual curvature, the initial residual bending configuration of CT under wellbore constraints, after running into the hole, is sinusoidal. The residual stresses and residual bending configuration significantly decrease the buckling load, making the buckling and buckling release of CT in the downhole an elastic-plastic process, exacerbating the helical lockup. The conclusions drawn in this study will improve CT models and contribute to the operational and economic success of CT services.

Field trial of expandable profile liners in a deep sidetrack well section and optimizable schemes approach for future challenges

Le Zhao,Yulin Tu,Heping Xie,Mingzhong Gao,Fei Liu 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.2

This study discusses challenges of running expandable profile liners (EPLs) to isolate trouble zones in directional section of a deep well, and summary the expandable profile liner technology (EPLT) field trial experience. Technically, the trial result reveals that it is feasible to apply the EPLT solving lost-circulation control problem and wellbore instability in the deep directional section. Propose schemes for optimizing the EPLT operation procedure to break through the existing bottleneck of EPLT in the deep directional section. Better-performing transition joints are developed to improve EPL string reliability in high borehole curvature section. High-performing and reliable expanders reduce the number of trips, offer excellent mechanical shaping efficiency, simplify the EPLT operation procedure. Application of the expansion and repair integrated tool could minimize the risk of insufficient expansion and increase the operational length of the EPL string. The new welding process and integrated automatic welding equipment improve the welding quality and EPL string structural integrity. These optimization schemes and recent new advancements in EPLT can bring significant economic benefits and promote the application of EPLT to meet future challenges.

Biomimetic-inspired highly sensitive flexible capacitive pressure sensor with high-aspect-ratio microstructures

Zhao Le,Yu Shihui,Li Junjun,Song Zichen,Wu Muying,Wang Xiuyu,Wang Xiaohu 한국물리학회 2021 Current Applied Physics Vol.31 No.-

The high sensitivity flexible capacitive pressure sensor (FCPS) manufactured in a fast and efficient way has friendly man-machine interaction function. In this paper, a high-sensitivity FCPS is developed by using a twostep template method to reproduce biomimetic microtower polydimethylsiloxane (PDMS) from the lotus leaf surface. The capacitive sensor is composed of a PDMS dielectric layer and the Cu nanowire electrodes sandwiching in the middle, with a high sensitivity of ~1.207 kPa 1, a low detection limit of less than 0.02 kPa and a fast response time of 61.6 ms. Particularly, the sensing performance can be kept basically unchanged when bent at a 5 mm radius. Moreover, the FCPS can withstand 4000 repeated tests and maintain stable performance, and the sensitivity is almost the same in the process of loading and unloading, suggesting the high robustness. These results demonstrates the FCPSs have potential applications in electronic wearables, human health monitoring and uneven surface applications.

A calculation on the Metal-Film Mixing by Intense Pulse Ion Beam (IPIB)

Le, X.Y.,Yan, S.,Zhao, W.J.,Wang, Y.G.,Xue, J.M. The Korean Vacuum Society 2003 Applied Science and Convergence Technology Vol.12 No.1

In this paper, we studied, by numerical calculation, a system, which was composed of metal-film and metal-substrate irradiated by IPIB with beam ion energy 250 keV, current density 10 to 250 A/$\textrm{cm}^2$. While the IPIB irradiation was going on, an induced effect named mixing occurred. In this case, metal-film and part of metal-substrate melted and mixed. The mixing state was kept as it was in melting phase due to the fast cooling rate. Our works were simulating the heating and cooling process via our STEIPIB program and tried to find proper parameters for a specific film-substrate system, 500 nmtitanium film coated on aluminum, to get best mixing results. The parameters calculated for such Ti-Al system were compared with the experimental results and were in good accordance to the experimental results.

Yaw wind effect on flutter instability of four typical bridge decks

Le-Dong Zhu,You-Lin Xu,Zhenshan Guo,Guang-Zhao Chang,Xiao Tan 한국풍공학회 2013 한국풍공학회지 Vol.17 No.3

When evaluating flutter instability, it is often assumed that incident wind is normal to the longitudinal axis of a bridge and the flutter critical wind speed estimated from this direction is most unfavorable. However, the results obtained in this study via oblique sectional model tests of four typical types of bridge decks show that the lowest flutter critical wind speeds often occur in the yaw wind cases. The four types of bridge decks tested include a flat single-box deck, a flat π-shaped thin-wall deck, a flat twin side-girder deck, and a truss-stiffened deck with and without a narrow central gap. The yaw wind effect could reduce the critical wind speed by about 6%, 2%, 8%, 7%, respectively, for the above four types of decks within a wind inclination angle range between -3° and 3°, and the yaw wind angles corresponding to the minimal critical wind speeds are between 4° and 15°. It was also found that the flutter critical wind speed varies in an undulate manner with the increase of yaw angle, and the variation pattern is largely dependent on both deck shape and wind inclination angle. Therefore, the cosine rule based on the mean wind decomposition is generally inapplicable to the estimation of flutter critical wind speed of long-span bridges under skew winds. The unfavorable effect of yaw wind on the flutter instability of long-span bridges should be taken into consideration seriously in the future practice, especially for supper-long span bridges in strong wind regions.

Synthetic Approaches to Natural Antioxidant Benzastatin E, F and G Analogues

Le, Thanh Nguyen,Yang, Su-Hui,Khadka, Daulat Bikram,Cho, Suk-Hee,Zhao, Chao,Cho, Won-Jea Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.12

For synthesis of benzastatin E, F and G analogues, the indole-2-carbaldehydes with or without substituents at C-5 position were prepared as key intermediates. Several synthetic attempts to achieve benzastatin E-G analogues were suggested using the indole-2-carbaldehyde intermediates.

S100A14 Promotes the Growth and Metastasis of Hepatocellular Carcinoma

Zhao, Fu-Tao,Jia, Zhan-Sheng,Yang, Qun,Song, Le,Jiang, Xiao-Jing Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6

Background: S100A14 has recently been implicated in the progress of several types of cancers. This study aimed to investigate the clinical significance and possible mechanisms of action of S100A14 in the invasion and metastasis of hepatocellular carcinoma (HCC). Methods: S100A14 expression in HCC was detected at mRNA and protein levels and its prognostic significance was assessed. Functional roles of S100A14 in HCC were investigated using MTT, BrdU, wound healing, transwell invasion assay and HCC metastatic mouse model. Results: S100A14 was significantly elevated in HCC tissues, correlated with multiple tumor nodes, high Edmondson-Steiner grade and vascular invasion. Multivariate Cox analysis showed that the S100A14 expression level was a significant and independent prognostic factor for overall survival (OS) of HCC patients (hazard ratio=1.98, 95% confidence interval=1.14-3.46, P=0.013). S100A14 promoted cell proliferation, invasion and metastasis of HCC in vitro and in vivo. Conclusion: These results suggest S100A14 is a novel prognostic marker and therapeutic target for HCC.

Sodium tanshinone IIA sulfonate attenuates angiotensin II-induced collagen type I expression in cardiac fibroblasts in vitro

Le Yang,Xiao-Jing Zou,Xiang Gao,Hao Chen,Jin-Long Luo,Zhao-Hua Wang,Qian-Sheng Liang,Guang-Tian Yang 생화학분자생물학회 2009 Experimental and molecular medicine Vol.41 No.7

Cardiac fibrosis occurs after pathological stimuli to the cardiovascular system. One of the most important factors that contribute to cardiac fibrosis is angiotensin II (Ang II). Accumulating studies have suggested that reactive oxygen species (ROS) plays an important role in cardiac fibrosis and sodium tanshinone IIA sulfonate (STS) possesses antioxidant action. We therefore examined whether STS depresses Ang II-induced collagen type I expression in cardiac fibroblasts. In this study, Ang II significantly enhanced collagen type I expression and collagen synthesis. Meanwhile, Ang II depressed matrix metalloproteinase- 1 (MMP-1) expression and activity. These responses were attenuated by STS. Furthermore, STS depressed the intracellular generation of ROS, NADPH oxidase activity and subunit p47phox expression. In addition, N-acetylcysteine the ROS scavenger, depressed effects of Ang II in a manner similar to STS. In conclusion, the current studies demonstrate that anti-fibrotic effects of STS are mediated by interfering with the modulation of ROS. Cardiac fibrosis occurs after pathological stimuli to the cardiovascular system. One of the most important factors that contribute to cardiac fibrosis is angiotensin II (Ang II). Accumulating studies have suggested that reactive oxygen species (ROS) plays an important role in cardiac fibrosis and sodium tanshinone IIA sulfonate (STS) possesses antioxidant action. We therefore examined whether STS depresses Ang II-induced collagen type I expression in cardiac fibroblasts. In this study, Ang II significantly enhanced collagen type I expression and collagen synthesis. Meanwhile, Ang II depressed matrix metalloproteinase- 1 (MMP-1) expression and activity. These responses were attenuated by STS. Furthermore, STS depressed the intracellular generation of ROS, NADPH oxidase activity and subunit p47phox expression. In addition, N-acetylcysteine the ROS scavenger, depressed effects of Ang II in a manner similar to STS. In conclusion, the current studies demonstrate that anti-fibrotic effects of STS are mediated by interfering with the modulation of ROS.

Fermented Pu-erh Tea Increases In Vitro Anticancer Activities in HT-29 Cells and Has Antiangiogenetic Effects on HUVECs

Zhao, Xin,Song, Jia-Le,Kim, Jong-Deog,Lee, Jong-Suk,Park, Kun-Young Begell House Inc. 2013 Journal of environmental pathology, toxicology, an Vol.32 No.4

Fatigue Behavior of Welded Thin-Walled T-joints between Circular and Square Hollow Secitons

Le-Wei Tong,X.L. Zhao,F.R.Mashiri,P.Grundy,Hong-Zhi Zheng 한국강구조학회 2006 International Journal of Steel Structures Vol.6 No.3

The fatigue behaviour of thin-walled CHS-to-SHS T-joints (t < 4 m) under in-plane bending are studied in this paper. Thefailure modes observed in the fatigue tests are described. Surface crack growth was recorded at progressive stages of fatiguelife, from initiation, through-thickness life and end of test failure. The characteristics of fatigue crack initiation and propagationare described. The stress concentration factors (SCFs) along the weld toes at both the circular brace and the square chord are-dimensional joint parameters on SCFs are discussed. The resultant SCFs are compared to both the SCFs from CHS and RHSparametric formulae in IIW guidelines. Both the fatigue tests and FE analyses showed that the hot spot locations of the CHS-to-SHS T-joints were located at the weld toe of the square hollow section chord.