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Hydration characteristics of cementitious composites containing calcium silicate slag powder
Ru Bai,Ju Zhang,Changwang Yan,Shuguang Liu,Xiaoxiao Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7
A significant portion of calcium silicate slag (CSS) waste is deposited in open landfills, leadingto various environmental concerns. CSS powder with high content of active β-C2S is apotential supplementary cementitious material. This study determined the isothermal hydrationheat flows of cementitious composites containing 0 − 40% CSS powder using an isothermalcalorimeter. The hydration kinetics and parameters were simulated and analyzed usingKrstulovic-Dabic model. Results indicated that the first exothermic peak of the cementitiouscomposite containing CSS powder shifted to the left and was significantly higher compared toPortland cement. The second exothermic peak also shifted to the left, but its value decreasedsignificantly. The cumulative hydration heat of the cementitious composite graduallydecreased with increasing of CSS powder content. The simulations from the kinetic modelshowed that the hydration rate of the entire process decreased with the increase of CSSpowder incorporation. These findings are expected to provide guidance for the use of CSSpowder in low-heat mortars or concrete.
Delayed Strength Development of Composite Cementitious with Calcium Silicate Slag
Ru Bai,Ju Zhang,Changwang Yan,Shuguang Liu,Xiaoxiao Wang,Zhijie Yang,Hao Jing 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.6
Using pulverized calcium silicate slag (CSS) to replace part of Portland cement (PC) as composite cementitious material is the most energy-saving and clean treatment method. The main objective of this study was to investigate the delayed strength development of the CSS-PC composite cementitious. The compressive strength of the composite cementitious with 10% to 40% CSS was tested, the delayed strength was calculated, and the delayed age was analyzed. Results showed that the delayed strength and delayed age increased with the increase in the substitution rate of CSS, which was determined by the ratio of C2S and C3S. Moreover, a compressive strength prediction model of CSS–PC composite cementitious was established based on the “core-shell” hydration model. The calculated value was compared with the specification value of each country to analyze whether the compressive strength of CSS-PC composite cementitious meets the engineering requirements.
Comparative Study on Anti-interference of Nondestructive Testing System with Annular Array Probes
Ru Bai,Zhiwei Li,Tengda Yang,Boyan Li,Aiyu Dou,Jiakun Tu,Jiaqi Li,Chuanjia Kou,Zhenghong Qian 한국자기학회 2024 Journal of Magnetics Vol.29 No.1
A pulsed eddy current nondestructive testing (PECT) system with annular array probes is designed for inner defect detection of metal pipelines. Tunneling magnetoresistance (TMR) array probes are applied to detect the magnetic signal generated by the inner surface defect of the metal pipelines. Compared to single probe structure, the annular array probes have advantages of high sensitivity, large scanning area and internal realtime detection. However, since many probes are densely arranged in the array, signal interference may occur between adjacent probes. Therefore, two methods of anti-interference, magnetic shielding and time-sharing excitation, are proposed in this work. By modeling and simulation, the working principles of the two antiinterference modes are analyzed and compared respectively. The experimental results show that both methods can reduce the interference between adjacent TMR probes. Compared with the time-sharing excitation method, the magnetic shielding method exhibits better performance with stronger differential signal peak and smaller error, and proves to be a more effective method for the defect detection of the metal pipelines.
Wen, Ru-Min,Zhang, Yi-Jing,Ma, Sha,Xu, Ying-Li,Chen, Yan-Su,Li, Hai-Long,Bai, Jin,Zheng, Jun-Nian Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9
Background: The neutrophil-to-lymphocyte ratio (NLR) is a strong predictor of mortality in patients with colorectal, lung, gastric cancer, pancreatic and metastatic renal cell carcinoma. We here evaluated whether preoperative NLR is an independent prognostic factor for non-metastatic renal cell carcinoma (RCC). Materials and Methods: Data from 327 patients who underwent curative or palliative nephrectomy were evaluated retrospectively. In preoperative blood routine examination, neutrophils and lymphocytes were obtained. The predictive value of NLR for non-metastatic RCC was analyzed. Results: The NLR of 327 patients was $2.72{\pm}2.25$. NLR <1.7 and NLR ${\geq}1.7$ were classified as low and high NLR groups, respectively. Chi-square test showed that the preoperative NLR was significantly correlated with the tumor size (P=0.025), but not with the histological subtype (P=0.095)and the pT stage (P=0.283). Overall survival (OS) and disease-free survival (DFS) were assessed using the Kaplan-Meier method. Effects of NLR on OS (P=0.007) and DFS (P=0.011) were significant. To evaluate the independent prognostic significance of NLR, multivariate COX regression models were applied and identified increased NLR as an independent prognostic factor for OS (P=0.015), and DFS (P=0.019). Conclusions: Regarding patient survival, an increased NLR represented an independent risk factor, which might reflect a higher risk for severe cardiovascular and other comorbidities. An elevated blood NLR may be a biomarker of poor OS and DFS in patients with non-metastatic RCC.
Quasi-nanocrystalline ZrB2 powder synthesized by saltassisted combustion and its formation mechanism
Faqi Zhan,Ru Bai,Xiao Liu,Ke Xu,Hua Zhang,Min Zhu,Yuehong Zheng,Shipeng Xu,Jie Sheng,Peiqing La 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.4
Nanoscale ceramic powders are very important for sintering densification and deviceization. A new salt-assisted combustionsynthesis process was used to prepare pure quasi-nanocrystalline zirconium diboride (ZrB2) powder on a large scale. TheZrO2-B2O3-Mg system with single NaCl salt and NaCl-KCl mixed salts as diluents was adopted to prepare ZrB2 powders. The results show that high-purity ZrB2 quasi-nanocrystalline powder with average size of ~105 nm and purity of 99.24% wasobtained by adding molten salts diluent. The impurity mainly existed in the form of Mg0.2Zr0.8O1.8 phase and Mg3B2O6 phase. The effects of diluent content and type on the adiabatic temperature, powder purity, particle size and microstructure of thesystem were studied. This work will provide theoretical basis and technical support for large-scale preparation of boride nanoceramicpowders.
Guided waves of porous FG nanoplates with four edges clamped
Zhao, Jing-Lei,She, Gui-Lin,Wu, Fei,Yuan, Shu-Jin,Bai, Ru-Qing,Pu, Hua-Yan,Wang, Shilong,Luo, Jun Techno-Press 2022 Advances in nano research Vol.13 No.5
Based on the nonlocal strain gradient (NSG) theory and considering the influence of moment of inertia, the governing equations of motion of porous functionally graded (FG) nanoplates with four edges clamped are established; The Galerkin method is applied to eliminate the spatial variables of the partial differential equation, and the partial differential governing equation is transformed into an ordinary differential equation with time variables. By satisfying the boundary conditions and solving the characteristic equation, the dispersion relations of the porous FG strain gradient nanoplates with four edges fixed are obtained. It is found that when the wave number is very small, the influences of nonlocal parameters and strain gradient parameters on the dispersion relation is very small. However, when the wave number is large, it has a great influence on the group velocity and phase velocity. The nonlocal parameter represents the effect of stiffness softening, and the strain gradient parameter represents the effect of stiffness strengthening. In addition, we also study the influence of power law index parameter and porosity on guided wave propagation.
Jing-Lei Zhao,Xu Chen,Gui-Lin She,Yan Jing,Ru-Qing Bai,Jin Yi,Hua-Yan Pu,Jun Luo 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.6
This paper presents an investigation on the free vibration characteristics of functionally graded nanocomposite double-beams reinforced by single-walled carbon nanotubes (SWCNTs). The double-beams coupled by an interlayer spring, resting on the elastic foundation with a linear layer and shear layer, and is simply supported in thermal environments. The SWCNTs gradient distributed in the thickness direction of the beam forms different reinforcement patterns. The materials properties of the functionally graded carbon nanotube-reinforced composites (FG-CNTRC) are estimated by rule of mixture. The first order shear deformation theory and Euler-Lagrange variational principle are employed to derive the motion equations incorporating the thermal effects. The vibration characteristics under several patterns of reinforcement are presented and discussed. We conducted a series of studies aimed at revealing the effects of the spring stiffness, environment temperature, thickness ratios and carbon nanotube volume fraction on the nature frequency.