Life Prediction and Long-Term Durability of Coated Steel Bars in Magnesium Oxychloride Concrete

Penghui Wang,Hongxia Qiao,Kefan Chen,Yuanke Li,Qiong Feng 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.7

The solution to the problem of corrosion of the steel bars in magnesium oxychloride cement concrete (MOCC) is to apply a coating that protects the steel. To investigate the coating’s long-term protective effect on the steel, a solution immersion accelerated corrosion test was carried out on coated reinforced MOCC for up to 2,160 days. Electrochemical tests were conducted every 90 days to measure the polarization curve and AC impedance during the steel bars’ corrosion process. Then, the corrosion current density that characterizes the corrosion of a coated steel bar was used as a degradation index, and the time to the coated steel bar’s corrosion was predicted based on the Wiener function. It was concluded that after 2,160 days of solution immersion, the coated steel bars’ corrosion current density was 0.063 μA·cm−2, indicating that the coating protected the steel bars in MOCC from corrosion well. Thdroughout the immersion process, the specimen’s corrosion current density showed a steady and increasing trend, and its polarization impedance showed a volatile growth trend. The degradation of the coated steel bars also obeyed the Wiener degradation process, and the bars reached a severely rusted state at 21,800d with a corrosion time of R0.6(t) is 10,650d.

Visual Analysis of the Protective Effect of Asphalt Coating on MOCC against Steel Corrosion and Rust Crack Formation

Penghui Wang,Hongxia Qiao,Qiong Feng,Cuizhen Xue 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

The constant current energization accelerated test was carried out to study the effect of asphalt coating on delaying reinforcement corrosion and rust-induced cracks in coated reinforced magnesium oxychloride cement concrete (CRMOCC). CRMOCC with different degrees of damage was scanned by adopting X-ray computed tomography (X-CT) technology, and the spatial information of rust and rust-induced cracks were analyzed visually and quantitatively. In addition, Scanning Electron Microscope (SEM) was used to analyze the non-uniformity of rust-induced crack formation. The results showed that the corrosion amount of coated reinforcement after energization was only 81.6% of that of uncoated reinforcement. Besides, no crack no cracking was observed on CRMOCC after 480h’s energization, while the rust-induced crack of reinforced magnesium oxychloride cement concrete (RMOCC) was 0.11 mm. The coating reduced the potential of rust-induced crack formation such that only three areas in CRMOCC were cracked, while RMOCC had cracks in eight areas. This study also found that interface transition zone (ITZ) played a dominant role in the formation of rust-induced cracks. The surface crack width in CRMOCC had an exponential relation with the crack volume and it had a linear relation with the volume of corrosion products. Further, there was an exponential relation between the volume loss of the reinforcement and the formation of rust-induced cracks. The correlation between surface crack width, corrosion products volume, rust-induced cracks volume and steel volume can be described by quadric surface. Results by SEM analysis indicated that in the ITZ of CRMOCC, Mg and O elements were the two main elements in the hydration products that were loose and needle-like. Furthermore, Si and O elements were the dominant materials in the non-interface transition zone (NITZ), resulting in relatively dense hydration products.

Standardized Treatment and Shortened Depression Course can Reduce Cognitive Impairment in Adolescents With Depression

Penghui Cao,Junjie Tan,Xuezhen Liao,Jinwei Wang,Lihuan Chen,Ziyan Fang,Nannan Pan 대한소아청소년 정신의학회 2024 소아청소년정신의학 Vol.35 No.1

Objectives: This study aimed to explore the influence of depression severity, disease course, treatment status, and other factors on cognitive function in adolescents with depressive disorders. Methods: Participants who met the inclusion criteria were enrolled in the study. Sociodemographic data of each participant were recorded, including age, sex, and family history of mental disorders. Zung’s Self-Rating Depression Scale was used to assess depression status in adolescents. Moreover, P300 and mismatch negativity (MMN) were used to objectively evaluate the participants’ cognitive function. Results: Only 26.8% of the adolescents with depression received standard antidepressant treatment. The latencies of N2 (267.80±23.34 ms), P3 (357.71±32.09 ms), and MMN (212.10±15.61 ms) in the adolescent depression group were longer than those in the healthy control group (p<0.01). Further analysis revealed that the latency of MMN was extended with increased levels of depression in adolescents. The MMN latency was short in participants with depression receiving standardized treatment. Furthermore, the latency of MMN was positively correlated with the severity and duration of depression (correlation coefficients were 0.465 and 0.479, respectively) (p<0.01). Conclusion: Receiving standardized treatment and shortening the course of depression can reduce cognitive impairment in adolescents with depression.

Water film covering characteristic on horizontal fuel rod under impinging cooling condition

Zhang Penghui,Wang Bowei,Chen Ronghua,Su G.H.,Tian Wenxi,Qiu Suizheng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11

Jet impinging device is designed for decay heat removal on horizontal fuel rods in a low temperature heating reactor. An experimental system with a fuel rod simulator is established and experiments are performed to evaluate water film covering capacity, within 0.0287e0.0444 kg/ms mass flow rate, 0 e164.1 kW/m2 heating flux and 13.8e91.4C feeding water temperature. An effective method to obtain the film coverage rate by infrared equipment is proposed. Water film flowing patterns are recoded and the film coverage rates at different circumference angles are measured. It is found the film coverage rate decreases with heating flux during single-phase convection, while increases after onset of nucleate boiling. Besides, film coverage rate is found affected by Marangoni effect and film accelerating effect, and surface wetting is significantly facilitated by bubble behavior. Based on the observed phenomenon and physical mechanism, dry-out depth and initial dry-out rate are proposed to evaluate film covering potential on a heating surface. A model to predict film coverage rate is proposed based on the data. The findings would have reliable guide and important implications for further evaluation and design of decay heat removal system of new reactors, and could be helpful for passive containment cooling research.

The influence of leveler Brilliant Green on copper superconformal electroplating based on electrochemical and theoretical study

Yaqiang Li,Penghui Ren,Yuanhang Zhang,Shengxu Wang,Jinqiu Zhang,Peixia Yang,Anmin Liu,Guangzhao Wang,Zhidong Chen,Maozhong An 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

Finding proper additive to achieve copper superconformal electrodeposition is significantly important. Brilliant Green exhibits excellent suppressing ability to the copper electrodeposition according to electrochemicalanalysis. Meanwhile, 100 mg/L was selected as the optimum value based on the convectiondependentadsorption behavior analysis of Brilliant Green. The interaction among three different additiveswas also investigated by applying chronopotentiometry as well as Brilliant Green compete to absorbon the cathode surface with SPS. Besides, the introduction of Brilliant Green can improve the transport ofcupric ions (Cu2+). The nucleation and growth of copper deposition is 3D diffusion-controlled instantaneousgrowth process at high overpotential but 3D diffusion-controlled mixing growth process at lowoverpotential. The synergistic suppressing mechanism was proposed to explain strong suppressing effectof BG on reduction of Cu2+ and the reaction pathways was studied theoretically. Copper interconnectlayer with high FP values (80.52 % to 84.38 %) was obtained with low SDT (about 28 lm) after electroplatingprocess was optimized. The surface morphology under the influence of Brilliant Green is compactand uniform and the grain size is reduced by Brilliant Green.

Cyclic response of self-centering SRC walls with frame beams as boundary

Lu Sui,Hanheng Wu,Penghui Tang,Tao Gong,Yifan Wang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.1

In recent years, earthquake resilient structures have become a research focus in the field of seismic engineering. In order to improve the resilience of steel frame - concrete wall panel structures, an innovative self-centering SRC wall panels with replaceable energy dissipaters is presented in the paper. For this purpose, the tested subassembly involving the self-centering SRC walls with frame beams as boundary was presented. The wall panels used in steel moment frames can provide the lateral resistance for structures. Test models of the wall panels with partial framed beams as boundary were suggested. The full-scale specimens were tested under cyclic lateral loads. The configuration of energy dissipaters and initial force of PT steel bars were varied to study their impacts on lateral behavior of the walls. Furthermore, the numerical models based on ABAQUS were developed. The parameter studies, including diameter of PT tendons, beam profile, beam span and wall width, were then conducted. The PT tendons can provide self-centering ability and the dampers are used to dissipate energy. The failure of the wall panels is mainly concentrated on energy dissipaters. This case makes it possible to repair the walls easily.

The inflammation regulation effects of Enterococcus faecium HDRsEf1 on human enterocyte-like HT-29 cells

Zhongyuan Tian,Lu Yang,Penghui Li,Yuncai Xiao,Jian Peng,Xiliang Wang,Zili Li,Mei Liu,Dingren Bi,Deshi Shi 한국통합생물학회 2016 Animal cells and systems Vol.20 No.2

Enterococcus faecium HDRsEf1 strain used as a probiotic to inhibit intestine inflammation and improve animal growth performance has been proved by our research team; however, it remains unclear how HDRsEf1 was recognized by intestine cells and how it activates the downstream pathway which benefit intestine health. In this study, HDRsEf1 was used to stimulate HT-29 cell line to partially uncover the intestine benefit mechanism of HDRsEf1. The results of cell viability assays showed that HDRsEf1 had no toxicity on HT-29 at concentrations up to 1 × 108 CFU/mL, HDRsEf1 could upregulate the TLR1, TLR2, and TLR6 mRNA level, especially TLR2, and significantly downregulate the mRNA level of TLR4, TLR5, TLR7, TLR8, but did not significantly affect the mRNA or protein level of MyD88, which suggests that HDRsEf1 activates the TLR2 pathway in an MyD88-independent pattern. HDRsEf1 could significantly downregulate the mRNA level of pro-inflammatory factors IL-1β, IL-6, IL-8, IL-12p35, IL-17, and TNF-α and did not affect the anti-inflammatory factors IL-10, PPAR-γ, and TSLP; besides HDRsEf1 did not upregulate the degradation of IκB in HT-29 cells. By contrast, enterohemorrhagic E. coli (EHEC) O157:H7 strongly up-regulated the mRNA level of pro-inflammatory factors IL-1β, IL-6, IL-8, IL-23, and TNF-α, downregulated obviously anti-inflammatory factor PPAR-ɣ, and obviously upregulated the degradation of IκB, which suggested that HDRsEf1 may act as an antagonist to regulate intestine inflammation response to intestine pathogen. These findings shed a light on the intestine benefit mechanism of HDRsEf1.

Prediction of steel corrosion in magnesium cement concrete based on two dimensional Copula function

Qiong Feng,Hongxia Qiao,Penghui Wang,Wei Gong 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.2

In order to solve the life prediction problem of damaged coating steel bar in magnesium cement concrete, this study tries to establish the marginal distribution function by using the corrosion current density as a single degradation factor. Representing the degree of steel corrosion, the corrosion current density were tested in electrochemical workstation. Then based on the Copula function, the joint distribution function of the damaged coating was established. Therefore, it is indicated that the corrosion current density of the bare steel and coated steel bar can be used as the boundary element to establish the marginal distribution function. By using the Frank-Copula function of Copula Archimedean function family, the joint distribution function of the damaged coating steel bar was successfully established. Finally, the life of the damaged coating steel bar has been lost in 7320d. As a new method for the corrosion of steel bar under the multi-dimensional factors, the two-dimensional Copula function has certain practical significance by putting forward some new ideas.

Accelerated Life Testing of Concrete based on Three-parameter Weibull Stochastic Approach

Xiangke Guo,Hongxia Qiao,Binrong Zhu,Penghui Wang,Shaoyong Wen 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4

Due to the time-varying characteristics of the durability of a concrete structure, a long duration of exposure and monitoring in natural conditions is required. The present research provided the indoor accelerated life testing of concrete, which simulated the special natural environments in the Xining area, including solar radiation, dry-wet circulation, freeze-thaw cycle, and salt corrosion. The measured dynamic modulus was taken as an evaluation index for the durability of concrete, and the change of the relative dynamic modulus of the specimen was studied. Meanwhile, a two-parameter Weibull distribution and three-parameter Weibull distribution were proposed based on the stochastic analysis method in order to assess the durability of concrete structure. It has been observed that the indoor accelerated life testing of concrete can make up for the shortcomings of long-term exposure under natural conditions. The variation of the relative dynamic modulus can effectively reflect the durability of the concrete degradation process. By contrasting two methods of stochastic analysis, the three-parameter Weibull distribution method is better to fit the accelerated lifedata of concrete specimens and to evaluate the durability of concrete structures during service.

SALT-INDUCED CHLOROPLAST PROTEIN (SCP) is Involved in Plant Tolerance to Salt Stress in Arabidopsis

Yong Zhuang,Yangxuan Liu,Yuxiang Li,Ming Wei,Yuying Tang,Penghui Li,Zhijian Liu,Hui Li,Weizao Huang,Songhu Wang 한국식물학회 2019 Journal of Plant Biology Vol.62 No.6

Soil salinization threats the agricultural productionand food security worldwide. Salt stress induced plantsenescence and chloroplast degradation. However, it remainslargely unknown how the chloroplast-localized proteins affectplant response to salt stress. Here, we characterized a novelgene (At5g39520) in Arabidopsis, which is induced by saltstress and encodes a chloroplast-localized protein. Thus, thisgene was named SALT-INDUCED CHLOROPLAST PROTEIN(SCP). A T-DNA insertion mutant of SCP gene (scp-1)showed the enhanced tolerance to salt stress, as indicated bythe increased survival rates, fresh weights and chlorophyllcontents compared with wild type plants under salt treatment. Salt-induced leaf senescence was also delayed in scp-1 mutant. The scp-1 complementation line and SCP overexpressionlines displayed the hypersensitivity to salt stress. The qRTPCRanalysis indicated that the transcripts of CHLOROPLASTVESICULATION (CV), which mediates stress-inducedchloroplast degradation, were altered in scp-1 mutant andSCP overexpression lines. Taken together, our results suggestthat SCP gene plays a negative role in response to salt stress andhas potential application for genetic modification of improvingplant tolerance to salt stress.