Fracture behavior of fly ash concrete containing silica fume

Peng Zhang,Ji-Xiang Gao,Xiao-Bing Dai,Tian-Hang Zhang,Juan Wang 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.59 No.2

Effect of silica fume on fresh properties, compressive strength at 28 days and fracture behavior of fly ash concrete composite were studied in this paper. Test results indicated that the fluidity and flowability of fly ash concrete composites decreased and fly ash concrete composite are more cohesive and appear to be sticky with the addition of silica fume. Addition of silica fume was very effective in improving the compressive strength at 28 days of fly ash concrete composite, and the compressive strength of fly ash concrete composite has a trend of increase with the increase of silica fume content. Results also indicated that all the fracture parameters of effective crack length, fracture toughness, fracture energy, the critical crack opening displacement and the maximum crack opening displacement of fly ash concrete composite decreased with the addition of silica fume. When the content of silica fume increased from 3% to 12%, these fracture parameters decreased gradually with the increase of silica fume content. Furthermore, silica fume had great effect on the relational curves of the three-point bending beam specimen. As the silica fume content increased from 3% to 12%, the areas surrounded by the three relational curves and the axes were becoming smaller and smaller, which indicated that the capability of concrete composite containing fly ash to resist crack propagation was becoming weaker and weaker.

Association Between Organic Dust Exposure and Adult-Asthma: A Systematic Review and Meta-Analysis of Case-Control Studies

Yan Zhang,Bing Ye,Hongling Zheng,Wei Zhang,Lin Han,Peng Yuan,Chao Zhang 대한천식알레르기학회 2019 Allergy, Asthma & Immunology Research Vol.11 No.6

Background: Exposure to organic dust has been widely investigated as a potential risk factor for asthma with different results. To clarify a potential relationship, we performed the present meta-analysis to integrate the results of studies examining the association of organic dust exposure with asthma. Methods: A comprehensive literature search in the electronic databases including EMBASE, PubMed and Cochrane Library databases (up to August 2018) was conducted. The adjusted odds ratios (ORs) with corresponding 95% confidence interval (CI) for organic dust exposure and asthma were retrieved and pooled to generate summary effect estimates in Revman 5.2. Results: Database searches retrieved 1,016 records. A total of 17 studies containing 3,619 cases and 6,585 controls were finally included in our meta-analysis. The summary estimates suggested that organic dust exposure was positively associated with asthma (OR, 1.48; 95% CI, 1.26–1.75; P < 0.00001), whether among population-based case-control studies (OR, 1.24; 95% CI, 1.13–1.35; P < 0.00001) or hospital-based case-control studies (OR, 2.79; 95% CI, 1.27–6.12; P = 0.01). Subgroup analysis showed that paper/wood (OR, 1.62; 95% CI, 1.38–1.90; P < 0.00001), flour/grain (OR, 1.48; 95% CI, 1.11–1.97; P = 0.008), and textile dust (OR, 1.50; 95% CI, 1.08–2.09; P = 0.02) exposure were significantly associated with asthma. Conclusions: Based on the studies evaluated, our meta-analysis results prompt that organic dust exposure is a risk factor inducing asthma, although precise analysis focus on specific organic dust materials is still warranted.

Experimental Investigation of a Curved Bridge under Hanging-Wall and Footwall Ground Motions

Peng Su,Xiaoyi Zhu,Bing Xue,Yanjiang Chen,Bing Zhang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.2

Shaking table test is an important means for the seismic research of structures, and many scholars have conducted shaking table tests on bridge structures. However, relatively few studies have focused on a curved bridge with a longitudinal slope. In this research, a 1/10-scale test model of a curved bridge with the different pier hights was designed by the principle of structural test similarity. The seismic records in the hanging-wall (HW), footwall (FW), and neutral zones were selected to conducted shaking table tests. Results showed that the seismic spectrum and peak value are remarkably affected by HW ground motions and have strong destructive power. The dynamic response of the curved bridge is remarkable under HW seismic records. The motion form of main girder is spatial and produces obvious rotation under HW seismic records. The displacement response of the curved bridge is closely related to the height of piers and the angle between pier displacement and seismic input directions. The displacement responses at the beam end and the bearing displacement are related to the motion state of the main girder.

Finite Element Simulation of the Tube Preforming and Hydroforming Process for an Automobile Subframe

Bing Yang,Shuhui. Li,Peng Hu,Zhongqin. Lin,Weigang Zhang 한국소성가공학회 2005 한국소성가공학회 컨퍼런스 Vol.2005 No.11

Effects of zinc sources and levels of zinc amino acid complex on growth performance, hematological and biochemical parameters in weanling pigs

Zhang, Yi,Ward, Terry Lynn,Ji, Fei,Peng, Chucai,Zhu, Lin,Gong, Limin,Dong, Bing Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.8

Objective: The objective of the study was to investigate the effects of zinc amino acid complex (ZnAA) on growth performance, hematological and biochemical parameters in weanling pigs. Methods: In Exp. 1, a total of 216 Duroc${\times}$Landrace${\times}$Large White weanling pigs were assigned randomly to 6 dietary treatments. Each treatment had 6 replicates (pens) with 6 pigs each. The diets were corn-soybean meal based with supplementation of 0, 20, 40, 80, 120 mg Zn/kg from ZnAA or 40 mg Zn/kg from feed-grade zinc sulfate. The experiment lasted 42 days. In Exp. 2, a total of 180 weanling pigs were assigned randomly to 3 dietary treatments supplemented with 0, 80, or 800 mg Zn/kg from ZnAA. Results: In Exp. 1, pigs fed 40 to 80 mg Zn/kg from ZnAA had higher (p<0.05) average daily gain (ADG) than the unsupplemented group during d 0 to 14. During d 0 to 42, the pigs fed 20 to 120 mg Zn/kg from ZnAA had increased (p<0.05) ADG. Pigs fed 20 to 120 mg/kg Zn from ZnAA had lower feed:gain (p<0.05), increased the activity of serum Cu-Zn superoxide dismutase on d 14, and increased serum Zn levels on d 42 (p<0.05). In Exp. 2, pigs fed diets with 800 mg Zn/kg had increased average daily feed intake during d 15 to 28 (p<0.05) compared to the unsupplemented group. During d 0 to 28, the pigs fed supplemental Zn had increased ADG (p<0.05). On d 14 and d 28, pigs fed supplemental Zn had higher the serum alkaline phosphatase activities (p<0.05). No significant differences were observed in the hematological parameters and organ indices. Conclusion: Supplementation with 20 to 80 mg/kg Zn from ZnAA improved the growth performance in weaned pigs. The piglets can tolerate up to 800 mg/kg Zn from ZnAA with limited potential health effects.

Efficacy of Cranial Electrotherapy Stimulation Combined with Biofeedback Therapy in Patients with Functional Constipation

( Bing Yan Gong ),( Hong Mei Ma ),( Xiao Ying Zang ),( Si Yuan Wang ),( Yi Zhang ),( Nan Jiang ),( Xi Peng Zhang ),( Yue Zhao ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2016 Journal of Neurogastroenterology and Motility (JNM Vol.22 No.3

Background/Aims A large number of studies have shown that function constipation (FC) has an extremely high incidence of mental and psychological disorders. Cranial electrotherapy stimulation (CES) was applied to the treatment of psychological disorders such as anxiety and depression. We explored the effects of CES combined with biofeedback therapy (BFT) on the psychological state, clinical symptoms, and anorectal function in patients with FC. Methods A total of 74 patients with FC were randomly divided into 2 groups. The control group received BFT. CES combined with BFT was carried out in the experiment group. All patients were assessed using the self-rating anxiety scale (SAS), self-rating depression scale (SDS), and Wexner constipation score at baseline and the end of each course. Anorectal manometry and balloon expulsion tests were performed before and after treatment. Results After treatment, the participants in the experiment group had significantly lower score SAS, SDS, and Wexner constipation scores than the control group (all P < 0.05). The number of successful expulsion in the experiment group was larger than the control group (P = 0.016). Conclusions CES combined with BFT was effective in improving the psychological status of anxiety, depression, and bowel symptoms in patients with FC. (J Neurogastroenterol Motil 2016;22:497-508)

The Admissible Multiperiod Mean Variance Portfolio Selection Problem with Cardinality Constraints

Peng Zhang,Bing Li 대한산업공학회 2017 Industrial Engineeering & Management Systems Vol.16 No.1

Uncertain factors in finical markets make the prediction of future returns and risk of asset much difficult. In this paper, a model,assuming the admissible errors on expected returns and risks of assets, assisted in the multiperiod mean variance portfolio selection problem is built. The model considers transaction costs, upper bound on borrowing risk-free asset constraints, cardinality constraints and threshold constraints. Cardinality constraints limit the number of assets to be held in an efficient portfolio. At the same time, threshold constraints limit the amount of capital to be invested in each stock and prevent very small investments in any stock. Because of these limitations, the proposed model is a mix integer dynamic optimization problem with path dependence. The forward dynamic programming method is designed to obtain the optimal portfolio strategy. Finally, to evaluate the model, our result of a meaning example is compared to the terminal wealth under different constraints.

Stiffness Modeling and Optimization of a 3-DOF Parallel Robot in a Serial-Parallel Polishing Machine

Peng Xu,Bing Li,Chi-Fai Cheung,Ju-Fan Zhang 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.4

Polishing is a kind of finishing process that can effectively reduce the surface defects and improve the form accuracy. This paper presents a novel hybrid machine with 6 degrees of freedom (DOF) serial-parallel topological structure used as an ultra-precision polishing equipment which is composed of a 3-DOF parallel robot, a 2-DOF serial robot and a turntable providing a redundant DOF. Due to the complexity of structure, stiffness performance evaluation of the parallel robot becomes a challenge. As a result, a theoretical model of the parallel robot based on the virtual work principle and the deformation superposition principle is formulated for analyzing the stiffness performance. With the developed model, a multi-objective dimensional optimization method is developed to maximize both the workspace volume and the global stiffness performance of the parallel robot. Artificial intelligence approach based on genetic algorithms is implemented to obtain an optimal combination of structural parameters. The effectiveness of this method is validated by simulation and the parallel robot with optimized structural parameters has a workspace with higher stiffness performance, hence justifies its suitability for high precision polishing.

The Admissible Multiperiod Mean Variance Portfolio Selection Problem with Cardinality Constraints

Zhang, Peng,Li, Bing Korean Institute of Industrial Engineers 2017 Industrial Engineeering & Management Systems Vol.16 No.1

Uncertain factors in finical markets make the prediction of future returns and risk of asset much difficult. In this paper, a model,assuming the admissible errors on expected returns and risks of assets, assisted in the multiperiod mean variance portfolio selection problem is built. The model considers transaction costs, upper bound on borrowing risk-free asset constraints, cardinality constraints and threshold constraints. Cardinality constraints limit the number of assets to be held in an efficient portfolio. At the same time, threshold constraints limit the amount of capital to be invested in each stock and prevent very small investments in any stock. Because of these limitations, the proposed model is a mix integer dynamic optimization problem with path dependence. The forward dynamic programming method is designed to obtain the optimal portfolio strategy. Finally, to evaluate the model, our result of a meaning example is compared to the terminal wealth under different constraints.

Removal of methylene blue from aqueous solutions by adsorption onto chemically activated halloysite nanotubes

Peng Luo,Bing Zhang,Yafei Zhao,Jinhua Wang,Haoqin Zhang,Jindun Liu 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.3

This study examines the adsorption behavior of methylene blue (MB) from aqueous solutions onto chemically activated halloysite nanotubes. Adsorption of MB depends greatly on the adsorbent dose, pH, initial concentration,temperature and contact time. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms and the Langmuir model agrees very well with experimental data. The maximum adsorption capacities for MB ranged from 91.32 to 103.63 mg·g^(−1 )between 298 and 318 K. A comparison of kinetic models applied to the adsorption data was evaluated for pseudo-first-order, pseudo-second-order, Elovich and intra-particle diffusion equation. The results showed the adsorption process was well described by the pseudo-second-order and intra-particle diffusion mode. Thermodynamic parameters suggest that the adsorption is spontaneous and endothermic. The obtained results indicated that the product had the potential to be utilized as low-cost and effective alternative for dye removal in wastewater.