Fatigue behavior of GFRP-concrete composite decks: An experimental and numerical study

Xiaodong Song,Yili Huang,Qiao Huang,Huakai Zheng 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.3

In order to ensure the safety of glass fiber reinforced polymer (GFRP)-concrete composite bridge deck, its static and fatigue behaviors were studied by both experimental and numerical method in this paper. First, static and fatigue loading tests were carried out to investigate the mechanical properties of the GFRP-concrete composite slab. The experimental results indicated that the composite bridge deck had a good fatigue resistance. Then, a finite element model was built and the accuracy of the model was verified by comparing the simulated results with the static experiment. Third, corresponding constitutive models and failure criterions were introduced to simulate the fatigue performance of GFRP-concrete composite slab by using both finite element method and theoretical layered method. Generally, the calculated values were in good agreement with the test values, and the proposed method can be used to predict the deflection and strain of the components. Finally, parametric analysis was conducted to investigate the stiffness degradation of the composite structure.

Green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in greenhouse with high temperature

Xiaodong Wang,Xingguo Liu1,Boqiang Qin,Zhaojun Gu,Hao Xu,Hao Zhu,Guofeng Cheng,Huang Liu 한국생태학회 2015 Journal of Ecology and Environment Vol.38 No.3

In order to understand the mechanisms of conversion between different algal dominance, an experiment was performed in a greenhouse from 22 June to 10 July 2011. The experiment included a treatment group subjected to three instances of nutrient enrichment and a control with no nutrient enrichment. The initial water was dominated by Ankistrodesmus of Chlorophyta. The average water temperature at 08:30 h and 14:00 h during the experiment was 31.6°C and 34.6°C, respec¬tively. The results showed that the total nitrogen (TN), total phosphorus (TP), dissolved total nitrogen (DTN), dissolved total phosphorus (DTP), and soluble reactive phosphorus (SRP) concentrations in the treatment were significantly higher than in the control (P < 0.05). However, the TN/TP and DTN/DTP in the control was higher than in the treatment (P < 0.05). The dominant algae in the control did not change during the experiment, while the dominant algae in the treat¬ment switched to Planktothrix of Cyanophyta on day 9. The chlorophyll a (Chl-a), wet weight of all algae, wet weight of Cyanophyta, and percentage of Cyanophyta in the control were all significantly lower than in the treatment (P < 0.05). Amounts of zooplankton, especially rotifers, were present at the end of the experimental period. The density of rotifers between the control and treatment was not significantly different (P > 0.05), while the copepod density in the treatment was higher than in the control (P < 0.05). We conclude that green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in a greenhouse with elevated temperature

Morphology characterization of micro-gap oil film of tilting pad hydrostatic bearing under extreme working conditions

Xiaodong Yu,Yanan Feng,Yan Zhao,Dianbin Huang,Jianhua Jiao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

Taking the hydrostatic support of the tiltable oil pad double rectangular cavity as the object, the fluid-thermal-solid coupling deformation analysis of the friction pair is carried out, and the three-dimensional morphology of the micro-gap oil film is obtained. An oil film thickness test device is built to verify the rationality of the numerical simulation method. It is found that the elastic deformations of rotational workbench and base under extreme loads are both concave deformations, the thermal deformations are both convex deformations, and the maximum thermal deformation is mainly concentrated on the outer oil sealing edge. The deformation of the downstream side oil sealing edge is higher than that of the reverse side oil sealing edge. The minimum oil film thickness is the minimum distance between the downstream side oil sealing edge and the lower surface of the hydrostatic guideway of the rotational workbench, where tribological failure is prone to occur.

ONE-STEP AND CONTROLLABLE SELF-ASSEMBLY OF Au/TiO2/CARBON SPHERES TERNARY NANOCOMPOSITES WITH A NANOPARTICLE MONOSHELL WALL

XIAODONG HAO,YUXIN ZHANG,JIA LIU,MENG DONG,MING HUANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2012 NANO Vol.7 No.4

In this work, stable and well dispersed colloidal Au/TiO2 binary nanoparticles (NPs) were synthesized initially. Meanwhile, they were immobilized simultaneously on colloidal carbon spheres (CSs), one of popular hard templates, to prepare hybrid self-assembly nanostructures. The morphology and crystal structure of these nanocomposites (NCs) were characterized by ¯eld emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), powder X-ray di®raction (XRD), thermogravimetric (TGA) and N2 sorption analysis. By controlling the NPs size, ratio of Au/TiO2 NPs, process temperature and time, and concentration of surfactants (e.g., MPA), Au/TiO2@CSs NCs could be tailored into core-shell nanostructures with various surface coverages of Au NPs and/or TiO2NPs. Interestingly, hollow spheres with a binary-nanoparticle monoshell could be achieved by calcinations of typical Au/TiO2@CSs NCs. In principle, these novel hybrid nanostructures with controllable functionality and high-surfacearea traits could be very promising photocatalysts for waste water treatment.

Green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in greenhouse with high temperature

Wang, Xiaodong,Liu, Xingguo,Qin, Boqiang,Gu, Zhaojun,Wu, Zongfan,Xu, Hao,Zhu, Hao,Cheng, Guofeng,Liu, Huang The Ecological Society of Korea 2015 Journal of Ecology and Environment Vol.38 No.3

In order to understand the mechanisms of conversion between different algal dominance, an experiment was performed in a greenhouse from 22 June to 10 July 2011. The experiment included a treatment group subjected to three instances of nutrient enrichment and a control with no nutrient enrichment. The initial water was dominated by Ankistrodesmus of Chlorophyta. The average water temperature at 08:30 h and 14:00 h during the experiment was $31.6^{\circ}C$ and $34.6^{\circ}C$, respectively. The results showed that the total nitrogen (TN), total phosphorus (TP), dissolved total nitrogen (DTN), dissolved total phosphorus (DTP), and soluble reactive phosphorus (SRP) concentrations in the treatment were significantly higher than in the control (P < 0.05). However, the TN/TP and DTN/DTP in the control was higher than in the treatment (P < 0.05). The dominant algae in the control did not change during the experiment, while the dominant algae in the treatment switched to Planktothrix of Cyanophyta on day 9. The chlorophyll a (Chl-a), wet weight of all algae, wet weight of Cyanophyta, and percentage of Cyanophyta in the control were all significantly lower than in the treatment (P < 0.05). Amounts of zooplankton, especially rotifers, were present at the end of the experimental period. The density of rotifers between the control and treatment was not significantly different (P > 0.05), while the copepod density in the treatment was higher than in the control (P < 0.05). We conclude that green algae dominance quickly switches to cyanobacteria dominance after nutrient enrichment in a greenhouse with elevated temperature.

The association between glaucoma and all-cause mortality in middle-aged and elderly Chinese people: results from the China Health and Retirement Longitudinal Study

Xiaoxu Huang,Mengqiao Xu,Minwen Zhou,Wenjia Liu,Xiaohuan Zhao,Xiaodong Sun 한국역학회 2023 Epidemiology and Health Vol.45 No.-

OBJECTIVES: This population-based, prospective cohort study investigated the association between glaucoma and mortality in older adults. METHODS: Participants aged 45 years or older at baseline (47.9% male) were enrolled in 2011 for the China Health and Retirement Longitudinal Study (CHARLS). All-cause mortality was observed during 7 years of follow-up. The baseline data were collected in the 2011 CHARLS, and participants were followed up for 7 years (until 2018). The risk of all-cause mortality was investigated using Cox proportional-hazards regression with age as the time scale, adjusting for significant risk factors and comorbid conditions. RESULTS: Among the 14,803 participants included, the risk of all-cause death was significantly higher among people with glaucoma than among those without glaucoma, after adjustment for other confounders (hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.04 to 2.03). In a subgroup analysis based on the mean age of death, among those who were 75 years and older (n=1,231), the risk of all-cause death was significantly higher in patients with glaucoma than in those without glaucoma (HR, 1.89; 95% CI, 1.24 to 1.89). CONCLUSIONS: Participants with glaucoma had a higher risk of all-cause mortality, especially those aged 75 years and above. Our findings revealed potential mechanisms underlying an association between glaucoma and all-cause mortality. They also highlighted the importance of glaucoma management to prevent premature death in middle-aged and older adults.

Cloning of porcine chemerin, ChemR23 and GPR1 and their involvement in regulation of Lipogenesis

( Jianfeng Huang ),( Jian Zhang ),( Ting Lei ),( Xiaodong Chen ),( Yan Zhang ),( Lulu Zhou ),( An Yu ),( Zhilong Chen ),( Ronghua Zhou ),( Zaiqing Yang ) 생화학분자생물학회 (구 한국생화학분자생물학회) 2010 BMB Reports Vol.43 No.7

Chemerin is a novel adipokine which is abundant in adipose tissue to promote adipocyte differentiation and with significant relativity to BMI and insulin sensitivity. We report here the molecular characterization of porcine chemerin and its receptors ChemR23 and GPR1, as well as their transcriptional regulation during lipogenesis. Chemerin was mainly expressed in liver, intestine, kidney and adipose tissue, consistent with the expression pattern of GPR1, but not ChemR23, which was predominantly present in spleen and temperately in adipose tissue. We further investigated the lipogenesis-related transcriptional activation of PPARγ and KLF15 on chemerin and its receptors. The data showed that KLF15, but not PPARγ, can up-regulate the mRNA level of chemerin, ChemR23 and GPR1, which was consistent with the results of luciferase assay that confirmed the effect of KLF15 on ChemR23 promoter. Taken together, our data provide basic molecular information for the further investigation on the function of chemerin in lipogenesis. [BMB reports 2010; 43(7): 491-498]

Half-metallicity and spin transport studies on quaternary CoCuMnSb Heusler alloy

Yinsheng Huang,Chao Jing,Yanning Wu,Yuanlei Zhang,Zhe Li,Xiaodong Sun,Miaofu Ye 한국물리학회 2019 Current Applied Physics Vol.19 No.11

Herein, the crystalline structure and spin transport properties of CoCuMnSb (CCMS) half-metallic Heusler alloy have been investigated with ab-initio calculations and nonequilibrium Green's function. Experimental and theoretical results reveal that CCMS alloy stabilizes in a highly ordered LiMgPdSn-type structure with lattice parameters of a=6.113 Å and α=90°, which match well with the reported lattice parameters of GaSb. Furthermore, the theoretical calculations indicate that CCMS exhibits perfect polarized spin at the Fermi level. Therefore, we have designed CCMS/GaSb heterostructure and CCMS/GaSb/CCMS magnetic tunnel junction (MTJ). Our architecture exhibits effective spin filtering and the MTJ produces a dramatic magnetoresistance ratio (~445). These outstanding properties marks CCMS as a strong system for applications in spintronics.

Experimental and Theoretical Study on the Flexural Performance of GFRP-Concrete-Steel Composite Beams

Zhaojie Tong,Xiaodong Song,Qiao Huang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.8

A novel GFRP (glass fiber-reinforced polymer)-concrete-steel composite beam bridge was proposed to prolong the service life of bridges. In order to investigate the flexural behavior of the composite beams, four-point bending tests and push-out tests were conducted. First, GFRP-concrete-steel composite beams with different interface types were fabricated and tested. Experimental results indicated the concrete ultimate strain and the ultimate deflection were increased because of the confining effect provided by GFRP plates. The GFRP-concrete interface had no obvious effect on flexural stiffness and flexural capacity. The slip effect of GFRPconcrete- steel beams was similar to that of steel-concrete beams. The failure process of GFRP-concrete-steel beams was different from that of steel-concrete beams due to the effect of the GFRP plate. Then, push-out specimens were tested to investigate the slip effect between GFRP-concrete decks and steel beams. The effect of GFRP plates on the studs was insignificant because of the large stud hole, and a regression formula of load-slip relationship was presented based on the experimental results. Finally, finite element model and theoretical model were employed to analyze the deflection calculation method and the flexural capacity calculation method, respectively.

A general methodology for reliability-based robust design optimization of computation-intensive engineering problems

Lai Xiongming,Huang Ju,Zhang Yong,Wang Cheng,Zhang Xiaodong 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.5

As for complex engineering structures, their single deterministic solutions need to be calculated with the help of computation-intensive finite element software, and the corresponding computation time always lasts very long. When referring to robust design optimization of complex engineering structures, the above expensive job should be repeatedly carried out for a considerable amount of time during the full optimization process. Hence, such repetitive jobs may be difficult to complete for most engineering applications. Aiming at this problem, the paper proposes a general methodology for reliability-based robust design optimization (RBRDO). Firstly, the improved formulation of the RBRDO problem is proposed based on the conventional RBRDO form, and the original probabilistic constraint functions in the improved formulation are changed into the deterministic ones by means of employing the performance measure approach (PMA). Secondly, the above-mentioned improved RBRDO problem is approximately replaced by a new sequence of approximate suboptimizations. For each suboptimization, its original PMA functions are replaced by the approximate explicit form only concerning the deterministic design variables rather than random variables. In this way, each suboptimization is deterministic. Furthermore, the trust-region method is adopted to ensure that the new sequence of suboptimization converge to the original improved RBRDO problem. Lastly, a test problem and three applications are adopted to demonstrate the effectiveness and efficiency of the above-proposed methods.PACS(optional, as per journal): 75.40.-s; 71.20.LP