Structural health monitoring of high-speed railway tracks using diffuse ultrasonic wave-based condition contrast: theory and validation

Kai Wang,Wuxiong Cao,Zhongqing Su,Pengxiang Wang,Xiongjie Zhang,Lijun Chen,Ruiqi Guan,Ye Lu 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.2

Despite proven effectiveness and accuracy in laboratories, the existing damage assessment based on guided ultrasonic waves (GUWs) or acoustic emission (AE) confronts challenges when extended to real-world structural health monitoring (SHM) for railway tracks. Central to the concerns are the extremely complex signal appearance due to highly dispersive and multimodal wave features, restriction on transducer installations, and severe contaminations of ambient noise. It remains a critical yet unsolved problem along with recent attempts to implement SHM in bourgeoning high-speed railway (HSR). By leveraging authors' continued endeavours, an SHM framework, based on actively generated diffuse ultrasonic waves (DUWs) and a benchmark-free condition contrast algorithm, has been developed and deployed via an all-in-one SHM system. Miniaturized lead zirconate titanate (PZT) wafers are utilized to generate and acquire DUWs in long-range railway tracks. Fatigue cracks in the tracks show unique contact behaviours under different conditions of external loads and further disturb DUW propagation. By contrast DUW propagation traits, fatigue cracks in railway tracks can be characterised quantitatively and the holistic health status of the tracks can be evaluated in a real-time manner. Compared with GUW- or AE-based methods, the DUW-driven inspection philosophy exhibits immunity to ambient noise and measurement uncertainty, less dependence on baseline signals, use of significantly reduced number of transducers, and high robustness in atrocious engineering conditions. Conformance tests are performed on HSR tracks, in which the evolution of fatigue damage is monitored continuously and quantitatively, demonstrating effectiveness, adaptability, reliability and robustness of DUW-driven SHM towards HSR applications.

Effect of asymmetrical tip clearances on energy performance and cavitation characteristics of NACA0009 hydrofoil in tidal energy

Like Wang,Xingqi Luo,Jinling Lu,Jianjun Feng,Guojun Zhu,Wei Wang,Kai Wang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.9

Tidal energy is an important renewable energy that uses the potential energy created by the rising and falling of ocean tides to generate electricity. The tip leakage vortex (TLV) and cavitation caused by the tip leakage flow have adverse effects on the energy conversion efficiency and stable operation of the tubular turbine. The selection of the tip clearance shape is critical. Therefore, the effects of four different combinations of asymmetrical tip clearance shapes on the energy and cavitation characteristics of hydrofoils are studied in this paper. The results show that the TLV remains unchanged when tipwall and endwall are sinusoidal and cosine curve shaped, respectively. When tip clearance is the combination of a flat tipwall and a sinusoidal endwall, the lift-drag ratio decreases by 10.72 %. The high shear stress region of tipwall near leading edge decreases. The flow resistance of the leakage flow decreases, and the leakage flow becomes more serious. The cavitation volume is 2.5 times that under the original flat tip clearance. When tip clearance is the combination of a flat tipwall and a cosine endwall, and the lift-drag ratio increases by 9.67 %. The shear stress increases, the leakage flow decreases. The swirling strength around the center of the vortex core is weakened. The cavitation volume is 3.81, with a decrease of nearly 30 %. A proper asymmetrical tip clearance can effectively improve the energy performance and cavitation characteristics of hydrofoils. This study provides theoretical support for the design and optimization of hydraulic machine with tip clearance.

Removal characteristics of Cd(II) ions from aqueous solution on ordered mesoporous carbon

Linhang Lu,Haibo Zhao,Lu Yan,Guowei Wang,Yulin Mao,Xin Wang,Kai Liu,Xiufang Liu,Qian Zhao,Tingshun Jiang 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.10

Ordered mesoporous carbon (CMK-3) was synthesized using SBA-15 mesoporous molecular sieve as a template and sucrose as carbon source. The materials were characterized by XRD, TEM and N2 physical adsorption technique. The resulting CMK-3 was used as adsorbent to remove Cd(II) ions from aqueous solution. The effect of pH, contact time and temperature on adsorption process was investigated in batch experiments. The results showed that the removal percentage could reach ca. 90% at the conditions of initial Cd(II) ions concentration of 20 mg/L, dose of 20mg, pH 6.5, contact time of 3h and 293K. Langmuir and Freundlich models were employed to describe the adsorption equilibrium. The kinetics data were described by the pseudo-first-order and pseudo-second-order models, respectively. The adsorption isotherm was well fitted to the Langmuir model, and the adsorption process was well described by the pseudo-second-order kinetic model.

Prognosis and Clinicopathology of CXCR4 in Colorectal Cancer Patients: a Meta-analysis

Li, Lu-Ning,Jiang, Kai-Tong,Tan, Peng,Wang, Ai-Hua,Kong, Qing-Yin,Wang, Cui-Yue,Lu, Hua-Rong,Wang, Jing Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9

The chemokine receptor 4 (CXCR4) has been widely used in diagnosis and prognosis of colorectal cancer (CRC). However, there is no current consensus on the impact of CXCR4 on CRC patients. The purpose of this study was to evaluate the prognostic and clinicopathological importance of CXCR4 in CRC patients. Databases, such as PubMed, Cochrane library, CBM and EMBASE updated to 2014 were searched to include eligible articles. We analysed correlations between CXCR4 expression and clinicopathological features and overall survival (OS). A total of 1, 055 CRC patients from twelve studies were included in the study. The pooled odds ratios (ORs) which indicated CXCR4 expression was likely to be associated with TNM stage (OR=0.43, CI=0.34-0.55, P<0.00001), lymph node status (OR=2.23, CI=1.23-4.05, P=0.008) and vascular invasion (OR=2.21, CI=1.11-4.39, P=0.02). Poor overall survival of CRC cancer was found to be significantly related to CXCR4 overexpression (hazard ratio (HR) 1.36 CI=1.17-1.59, P<0.0001), whereas combined ORs revealed that CXCR4 expression had no correlation with gender or differentiation. Based on the published studies, CXCR4 overexpression in patients w ith CRC indicates poor survival outcome and clinicopathological factors.

WHY TILAPIAS FROM CHINA ARE THE CHEAPEST? AN ANALYSIS BASED ON STATISTICS

Lu Jianzhen,Wang Kai 한국수산과학회 양식분과 2015 한국수산과학회 양식분과 학술대회 Vol.2015 No.5

Kojic Acid Protects C57BL/6 Mice from Gamma-irradiation Induced Damage

Wang, Kai,Liu, Chao,Di, Chan-Juan,Ma, Cong,Han, Chun-Guang,Yuan, Mei-Ru,Li, Peng-Fei,Li, Lu,Liu, Yong-Xue Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.1

The radioprotective effects of a single administration of kojic acid (KA) against ionizing radiation were evaluated via assessment of 30-day survival and alterations of peripheral blood parameters of adult C57BL/6 male mice. The 30-day survival rate of mice pretreated with KA (75 or 300 mg/kg body weight, KA75 or KA300) subcutaneously 27 h prior to a lethal dose (8 Gy, 153.52 cGy/min) of gamma irradiation was higher than that of mice irradiated alone (40% or 60% vs 0%). It was observed that the white blood cell (WBC) count/the red blood cell (RBC) count, haemoglobin content, haematocrit and platelet count of mice with or without KA pretreatment as exposed to a sub-lethal dose (4 Gy, 148.14 cGy/min) of gamma irradiation decreased maximally at day 4/day 8 post-irradiation. Although the initial WBC values were low in KA300 or WR-2721 (amifostine) groups, they significantly recovered to normal at day 19, whereas in the control group they did not. The results from the cytotoxicity and cell viability assays demonstrated that KA could highly protect Chinese hamster ovary (CHO) cells against ionizing radiation with low toxicity. In summary, KA provides marked radioprotective effects both in vivo and in vitro.

Tazarotene-Induced Gene 1 Interacts with DNAJC8 and Regulates Glycolysis in Cervical Cancer Cells

Wang, Chun-Hua,Shyu, Rong-Yaun,Wu, Chang-Chieh,Chen, Mao-Liang,Lee, Ming-Cheng,Lin, Yi-Yin,Wang, Lu-Kai,Jiang, Shun-Yuan,Tsai, Fu-Ming Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.6

The tazarotene-induced gene 1 (TIG1) protein is a retinoidinducible growth regulator and is considered a tumor suppressor. Here, we show that DnaJ heat shock protein family member C8 (DNAJC8) is a TIG1 target that regulates glycolysis. Ectopic DNAJC8 expression induced the translocation of pyruvate kinase M2 (PKM2) into the nucleus, subsequently inducing glucose transporter 1 (GLUT1) expression to promote glucose uptake. Silencing either DNAJC8 or PKM2 alleviated the upregulation of GLUT1 expression and glucose uptake induced by ectopic DNAJC8 expression. TIG1 interacted with DNAJC8 in the cytosol, and this interaction completely blocked DNAJC8-mediated PKM2 translocation and inhibited glucose uptake. Furthermore, increased glycose uptake was observed in cells in which TIG1 was silenced. In conclusion, TIG1 acts as a pivotal repressor of DNAJC8 to enhance glucose uptake by partially regulating PKM2 translocation.

Decellularized Human Umbilical Artery Exhibits Adequate Endothelialization in Xenogenic Transplantation

Kai Hsia,Tien-Shiang Wang,Chin-Su Liu,Chih-Kuan Su,Chien-Chin Chen,Chang-Ching Yeh,Hsinyu Lee,Chao-Ling Yao,Tsung-Yu Tseng,Shih-Hwa Chiou,Hsu Ma,Chih-Hsun Lin,Jen-Her Lu 한국생물공학회 2023 Biotechnology and Bioprocess Engineering Vol.28 No.3

Decellularized human umbilical arteries (dHUA) is an off-the-shelf graft that can potentially serve as vascular scaffolds in tissue engineering of small-diameter vascular grafts. This research aimed to investigate that dHUA could exhibit adequate endothelialization for a long term in xenogenic transplantation. 13 dHUAs were implanted in rat abdominal aortas up to 90 days. Rats were divided into three groups in terms of survival period: Group 1, one to seven days (n = 6); Group 2, 14 to 30 days (n = 4) and Group 3, 90 days (n = 3). The explants were analyzed by histological, immunohistochemistry and magnetic resonance angiography (MRA) examination. Allograft implantation of 12 decellularized rat abdominal aortas` were processed the same way as the rat in order to make a comparison for survival rates (Group 1, n = 5; Group 2, n = 4; Group 3, n = 3). The results demonstrated that the survival rates of xenograft and allograft implantation were estimated to be 59.2% vs. 58.3% in Group 1, 50.7% vs. 58.3% in Group 2 and 3. Grafts harvested from Group 2 were showed CD31, endothelial nitric oxide synthase expression at intima, and α-smooth muscle actin, CD45, CD68 and CD168 expression at the tunica externa. A layer structure with obvious endothelialization and fiber regeneration/orientation could be inspected from the explants of Group 3. MRA demonstrated the patency of dHUA on day 30 and 90. In conclusion, more than 50% dHUA maintained patency in the xenogenic model till 90 days after surgery. A mature vessel-like functional structure with intact endothelial layer was observed then. This warrants further study in the reinforcement of decellularized vascular scaffolds.

A Privacy-preserving and Energy-efficient Offloading Algorithm based on Lyapunov Optimization

Lu Chen,Hongbo Tang,Yu Zhao,Wei You,Kai Wang 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.8

In Mobile Edge Computing (MEC), attackers can speculate and mine sensitive user information by eavesdropping wireless channel status and offloading usage pattern, leading to user privacy leakage. To solve this problem, this paper proposes a Privacy-preserving and Energy-efficient Offloading Algorithm (PEOA) based on Lyapunov optimization. In this method, a continuous Markov process offloading model with a buffer queue strategy is built first. Then the amount of privacy of offloading usage pattern in wireless channel is defined. Finally, by introducing the Lyapunov optimization, the problem of minimum average energy consumption in continuous state transition process with privacy constraints in the infinite time domain is transformed into the minimum value problem of each timeslot, which reduces the complexity of algorithms and helps obtain the optimal solution while maintaining low energy consumption. The experimental results show that, compared with other methods, PEOA can maintain the amount of privacy accumulation in the system near zero, while sustaining low average energy consumption costs. This makes it difficult for attackers to infer sensitive user information through offloading usage patterns, thus effectively protecting user privacy and safety.

Cancer Research Advances Regarding the CKLF-like MARVEL Transmembrane Domain Containing Family

Lu, Jia,Wu, Qian-Qian,Zhou, Ya-Bo,Zhang, Kai-Hua,Pang, Bing-Xin,Li, Liang,Sun, Nan,Wang, Heng-Shu,Zhang, Song,Li, Wen-Jian,Zheng, Wei,Liu, Wei Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.6

The CKLF-like MARVEL transmembrane domain-containing family (CMTM) is a novel family of genes first reported at international level by Peking University Human Disease Gene Research Center. The gene products act between chemokines and the transmembrane-4 superfamily. Located in several human chromosomes, the CMTMs CKLF and CMTM1 to CMTM8 may be unregulated in tumors and act as potential tumor suppressor genes with important roles in the immune, male reproductive and hematopoietic systems. In-depth studies in recent years established a close relation between CMTMs and tumorigenesis and metastasis. The CMTM family has a significant clinical value in diagnosis and treatment of diseases linked to tumors and the immune system.