Structural reliability updating using experimental data

Lisha Zhu,Xianzhen Huang,Cong Yuan,Zunling Du 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

Conventional reliability analysis requires the information from an existing structure, such as a mechanical model and random distributed inputs. In many engineering problems, a state monitoring system commonly provides experimental or monitoring data, which can be used to update the initial estimation for structural reliability to reduce prediction uncertainty. A critical issue in this process is the manner in which the existing information and new data can be reasonably integrated into a reliability estimation. In this paper, Bayesian updating approach is applied to incorporate the additional data. Firstly, a theoretical model is established to predict the prior distribution of the limit state function (LSF) with the first-order reliability method. Then, the Bayesian inference theory is applied to update the probability distribution parameters of LSF using the acquired experimental or monitoring data. The analytical form of the LSF’s posterior distribution is derived under the assumption that the experimental test error follows a normal distribution. To improve accuracy, a second-order reliability method is proposed based on the theory of saddlepoint approximation. Markov chain Monte Carlo simulation is used to derive a general method for updating the LSF’s distribution using the experimental or monitoring data. Finally, three numerical examples are provided to illustrate the proposed framework’s validity.

Numerical study on the cavitating flow through poppet valves concerning the influence of flow instability on cavitation dynamics

Cong Yuan,Lisha Zhu,Shiqi Liu,Du Zunling,He Li 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

The flow dynamics of the cavitating jet through poppet valves inevitably suffers from the influence of varying openness, but the relevant mechanism remains unclear. Hence, the present study conducts a numerical study on the cavitating flow phenomenon inside poppet valves with two valve seat structures, in order to examine the flow mechanisms underlying varying cavitation phenomenon at different openness. According to the results, the overall cavitation distribution as well as the morphology feature follows a similar pattern due to the same inception mechanism irrelevant of the openness amount. However, examination of the dynamic behaviors confirms discernable variation in 2 coupling effects between flow instability and cavitation. The flow separation at the poppet trailing edge produces non-cavitation flow instability at 0.4 mm openness and attached cavitation at 0.8 mm, which amalgamate with upstream-shed vortex cavitation. The stably attached cavitation within the chamfered groove at 0.4 mm, as the source of non-cavitation flow instability, and the detached cavitation at 0.6 and 0.8 mm openness produce vortex cavitation at the free shearing side. The substantial variation in these two coupling effects contributes sensibly to the increase in the overall cavitation intensity. Meanwhile, the weakened coupling effect between the free shearing vortex and wall shearing vortex, as a consequence of increased potential core thickness at larger openness, leads to the attenuated vortex cavitation at the wall poppet side. Additionally, the vortex cavitation at free shearing side has a larger size in the chamfered valve seat case, due to the coupling of shed flow instability with the Kelvin-Helmholtz instability. As a conclusion, the inception mechanism for the cavitation remains unchanged with openness, while the difference in flow instabilities as well as the associated coupling effects with cavitation contributes to the variation in cavitation intensity.

Superior adsorption of Re(VII) by anionic imprinted chitosan-silica composite: Adsorption performance, selectivity and mechanism study

Ying Xiong,Lisha Xie,Long Zhu,Yuejiao Wang,Weijun Shan,Zhenning Lou,Junshuo Cui,Haibiao Yu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

In this study, a three-dimensional chitosan/mesoporous silica composite material (I-CTS-KIT-6) was successfullysynthesized by one-step method using ion imprinting technology. To overcome the enormouscost problem, MoO4 2 with similar radius to ReO4was selected as template ion. In addition, the adsorbentwas prepared by using glutaraldehyde and chitosan as crosslinking agents and monomers and TEOS assilicon source in the process of imprinting. The effects of pH values, mass of chitosan and templateion, contact time, temperature and concentration on Re(VII) adsorption were studied. The resultsrevealed that the I-CTS-KIT-6 has the saturated adsorption capacity of 368.8 mg g1 at pH 3.0 for Re(VII), and the adsorption process corresponded to Langmuir isotherm and pseudo-second-order kinetics. Especially, the I-CTS-KIT-6 has higher selectivity for rhenium ions compared with the non-imprintedadsorbent. To verify the adsorption mechanism, density functional theory (DFT) was adopted to analyzethe binding patterns of Re(VII) with the I-CTS-KIT-6. The test analysis and calculation results further mentionedthat the adsorption mechanism is mainly three N atoms of I-CTS-KIT-6 coordinated with threeoxygen atoms of ReO4, which provides the theoretical foundations and explanations for adsorptionprocess.

Temperature dependent defence of Nicotiana tabacum against Cucumber mosaic virus and recovery occurs with the formation of dark green islands

Feifei Zhao,Yanan Li,Li-juan Chen,Lisha Zhu,Han Ren,Honghui Lin,Dehui Xi 한국식물학회 2016 Journal of Plant Biology Vol.59 No.3

Temperature is an important environmental factor controlling plant growth, development, and immune response. However, the role of temperature in plant disease resistance is still elusive. In the present study, the potential effects of temperature on the interaction between Nicotiana tabacum and Cucumber mosaic virus (CMV) were investigated. Our results indicated that N. tabacum plants displayed severe symptoms at early stage of post inoculation at high temperature (HT, 28°C), associated with higher viral replication level, more serious stress damages. By contrast, low temperature (LT, 18°C) effectively delayed the replication of CMV compared with elevated temperatures. Additionally, quantitative real-time PCR analyses revealed that lower temperatures (≤ 24°C) promote salicylic acid (SA) dependent responses, whereas higher temperatures (> 24°C) activate the genes expression of jasmonic acid (JA) pathway. Interestingly, the dark green islands (DGIs) appeared much earlier in CMV-inoculated plants grown at HT compared with those at LT and the accumulation of virus small interfering RNAs in plants were significantly up-regulated under elevated temperatures at early stage of post inoculation. Taken together, these results indicated that temperature changes had important effects on plant defence response, and different temperatures could induce different immune pathways of N. tabacum against CMV infection.

A Single-Arm Phase II Study of Nab-Paclitaxel Plus Gemcitabine and Cisplatin for Locally Advanced or Metastatic Biliary Tract Cancer

Ting Liu,Qing Li,Zhen Lin,Chunhua Liu,Wei Pu,Shasha Zeng,Jun Lai,Xuebin Cai,Lisha Zhang,Shuyang Wang,Miao Chen,Wei Cao,Hongfeng Gou,Qing Zhu 대한암학회 2024 Cancer Research and Treatment Vol.56 No.2

Purpose Patients with advanced biliary tract cancer (BTC) have a poor survival. We aim to evaluate the efficacy and safety of nab-paclitaxel plus gemcitabine and cisplatin regimen in Chinese advanced BTC patients.Materials and Methods Eligible patients with locally advanced or metastatic BTC administrated intravenous 100 mg/m² nab-paclitaxel, 800 mg/m² gemcitabine, and 25 mg/m² cisplatin every 3 weeks. The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS) and adverse events, while exploratory endpoint was the association of biomarkers with efficacy.Results After the median follow-up of 25.0 months, the median PFS and OS of 34 enrolled patients were 7.1 months (95% confidence interval [CI], 5.4 to 13.7) and 16.4 months (95% CI, 10.9 to 23.6), respectively. The most common treatment-related adverse events at ≥ 3 grade were neutropenia (26.5%) and leukopenia (26.5%). Survival analyses demonstrated that carcinoembryonic antigen (CEA) levels could monitor patients’ survival outcomes. A significant increase in the number of infiltrating CD4+ cells (p=0.008) and a decrease in programmed death-1–positive (PD-1+) cells (p=0.032) were observed in the response patients.Conclusion In advanced BTC patients, nab-paclitaxel plus gemcitabine and cisplatin regimen showed therapeutic potential. Potential prognostic factors of CEA levels, number of CD4+ cells and PD-1+ cells may help us maximize the efficacy benefit.