Comparison of long-term behavior between prestressed concrete and corrugated steel web bridges

Yulin Zhan,Fang Liu,Zhongguo John Ma,Zhiqiang Zhang,Zengqiang Duan,Ruinian Song 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.6

Prestressed concrete (PC) bridges using corrugated steel webbing have emerged as one of the most promising forms of steel-concrete composite bridge. However, their long-term behavior is not well understood, especially in the case of largespan bridges. In order to study the time-dependent performance, a large three-span PC bridge with corrugated steel webbing was compared to a similar conventional PC bridge to examine their respective time-dependent characteristics. In addition, a threedimensional finite element method with step-by-step time integration that takes into account cantilever construction procedures was used to predict long-term behaviors such as deflection, stress distribution and prestressing loss. These predictions were based upon four well-established empirical creep prediction models. PC bridges with a corrugated steel web were observed to have a better long-term performance relative to conventional PC bridges. In particular, it is noted that the pre-cambering for PC bridges with a corrugated steel web could be smaller than that of conventional PC bridges. The ratio of side-to-mid span has great influence on the long-term deformation of PC bridges with a corrugated steel web, and it is suggested that the design value should be between 0.4 and 0.6. However, the different creep prediction models still showed a weak homogeneity, thus, the further experimental research and the development of health monitoring systems are required to further progress our understanding of the long-term behavior of PC bridges with corrugated steel webbing.

Effect of Sodium Tripolyphosphate on Clay Tolerance of Polycarboxylate Superplasticizer

Hongbo Tan,Yulin Guo,Baoguo Ma,Jian Huang,Benqing Gu,Fubing Zou 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

High fluidity concrete has been widely used in modern civil engineering project to ensure that the highly efficient construction process canbe achieved. Generally, the fluidity can be obtained with the incorporation of superplasticizer system composed of polymers and retarders. Sodium tripolyphosphate (STPP), a commonly used retarder in cement-based material, can obviously increase the dispersion ofpolycarboxylate superplasticizer (PCE), and this has been widely employed in real concrete. However, the effect of STPP on clay toleranceof PCE has not been confirmed until now, and it is still uncertain whether STPP in PCE system has positive or negative effect on workabilityof fresh concrete with poor-quality aggregates containing montmorillonite (Mt) which is one of the most harmful clay minerals. In this study,the effect of STPP on fluidity of cement-Mt paste with PCE has been investigated. The fluidity was tested with mini slump to assess the claytolerance of PCE. The adsorption amount of PCE and STPP in Mt suspension was tested with total organic carbon analyzer and inductivecoupled plasma emission spectrometer to characterize the adsorption behavior. The interlayer spacing was evaluated with X-rayDiffractometer and the structure of intercalated Mt by PCE was characterized with Fourier-transform infrared spectrometer and thermogravimetric analyzer, and these results were used to illustrate the effect of STPP on intercalation of PCE. Finally, the dispersion model wasproposed to reveal the mechanism behind. The results show that STPP can disperse the Mt particles and increase adsorption amount of PCEin Mt suspension, thereby accelerating rather than hindering the intercalation of PCE into Mt. The fluidity of cement-Mt paste with PCESTPPsystem is depended on the added dosage of STPP: with the dosage less than 0.20%, the contribution of STPP to dispersing the cementparticles predominates, hence increasing the fluidity of the paste and improving the clay tolerance; while with the dosage more than 0.20%,the acceleration of the intercalation of PCE resulting from STPP becomes predominant, thereby reducing the fluidity of the paste. This resultcan provide useful experience for the improvement in clay tolerance of PCE in real concrete with poor aggregate containing Mt.

The combination of deoxynivalenol and zearalenone at permitted feed concentrations causes serious physiological effects in young pigs

Feng Chen,Yulin Ma,Chunyi Xue,Jingyun Ma,Qingmei Xie,Genhu Wang,Yingzuo Bi,Yongchang Cao 대한수의학회 2008 JOURNAL OF VETERINARY SCIENCE Vol.9 No.1

This study was to investigate the effects of the combination of deoxynivalenol (DON) and zearalenone (ZON) on pigs. Twenty-four weaning piglets were divided into a control group fed a diet free of mycotoxins and a toxin group fed a diet containing 1 mg/kg DON and 250 μg/kg ZON. The results showed that supplementation of DON and ZON in diets had extensive effects on pigs. More specifically, DON and ZON caused levels of total protein, albumin, and globulin in sera to decrease (p < 0.05) by 14.5%, 6.5% and 11.3%, respectively, and at the same time increased (p < 0.05) the serum enzyme activities of γ-glutamyltransferase, aspartate aminotransferase and alanine aminotransferase by 72.0%, 32.6% and 36.6%, respectively. In addition, DON and ZON decreased (p < 0.05) the level of anticlassical swine fever antibody titers by 14.8%. Real-time PCR showed that DON and ZON caused the mRNA expression levels of IFN-γ, TNF-α, IL-2, to decrease (p < 0.05) by 36.0%, 29.0% and 35.4%, respectively. Histopathological studies demonstrated that DON and ZON caused abnormalities in the liver, spleen, lymph nodes, uterus, and kidney. The concentrations of DON and ZON used in this study are in line with the published critical values permitted by BML. Our study clearly put the standard and adequacy of safety measures for these toxins into question. The authors suggest that with the increasing availability of cellular and molecular technologies, it is time to revisit the safety standards for toxins in feeds so as to make feeds safer, providing consumers with safer products. This study was to investigate the effects of the combination of deoxynivalenol (DON) and zearalenone (ZON) on pigs. Twenty-four weaning piglets were divided into a control group fed a diet free of mycotoxins and a toxin group fed a diet containing 1 mg/kg DON and 250 μg/kg ZON. The results showed that supplementation of DON and ZON in diets had extensive effects on pigs. More specifically, DON and ZON caused levels of total protein, albumin, and globulin in sera to decrease (p < 0.05) by 14.5%, 6.5% and 11.3%, respectively, and at the same time increased (p < 0.05) the serum enzyme activities of γ-glutamyltransferase, aspartate aminotransferase and alanine aminotransferase by 72.0%, 32.6% and 36.6%, respectively. In addition, DON and ZON decreased (p < 0.05) the level of anticlassical swine fever antibody titers by 14.8%. Real-time PCR showed that DON and ZON caused the mRNA expression levels of IFN-γ, TNF-α, IL-2, to decrease (p < 0.05) by 36.0%, 29.0% and 35.4%, respectively. Histopathological studies demonstrated that DON and ZON caused abnormalities in the liver, spleen, lymph nodes, uterus, and kidney. The concentrations of DON and ZON used in this study are in line with the published critical values permitted by BML. Our study clearly put the standard and adequacy of safety measures for these toxins into question. The authors suggest that with the increasing availability of cellular and molecular technologies, it is time to revisit the safety standards for toxins in feeds so as to make feeds safer, providing consumers with safer products.

Design and simulation of 500 MHz single cell superconducting RF cavity for SILF

Sun Yanbing,Ma Wei,Yuan Nan,Ge Yulin,Yang Zhen,Zou Liping,Lu Liang 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.1

Shenzhen Innovation Light source Facility (SILF) is a 3.0 GeV fourth generation diffraction limited synchrotron light source currently under construction in Shenzhen. The SILF storage ring is proposed to use two 500 MHz single cell superconducting radio frequency (SRF) cavities to provide 2.4 MV RF voltage. In this study, we examined the geometric structure of mature CESR superconducting cavities and adopted a beam-pipe-type extraction scheme for high-order modes (HOM). One of the objectives of SRF cavity design and optimization in this study is to reduce Ep/Eacc and Bp/Eacc as much as possible to reduce power loss and ensure stable operation of the cavity. To reduce the risk of beam instability and thermal breakdown, the HOM and Multipacting (MP) are simulated. Moreover, the mechanical properties of the cavity are analyzed, including frequency sensitivity from pressure of liquid helium (LHe), stress, tuning, Lorentz force detuning (LFD), the microphone effect, and buckling. By comprehensive design and optimization of 500 MHz single-cell SRF cavities, a superconducting cavity for SILF storage ring was developed. This paper will detailed present the design and simulation.

An Octree-Based Two-Step Method of Surface Defects Detection for Remanufacture

Yan He,Wen Ma,Yufeng Li,Chuanpeng Hao,Yulin Wang,Yan Wang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.2

Accurate and quick detection has a significant bearing on overall productivity of remanufacture. 3D scanning technologies have been widely applied in defects detection by comparing the damaged model with the nominal model. In this process, a huge amount of point cloud data is required to ensure detection accuracy whereas resulting in large storage space and long processing time of detection. This paper proposed an efficient two-step method based on octree to detect defects accurately and quickly for remanufacturing. In this method, the damaged point cloud and the nominal point cloud are first registered. Then a two-step detection approach is developed to extract the surface defects, coarse detection and detailed extraction, where the octree method is applied to create an effective topology of discrete points and perform the Boolean operation for defects extraction. In coarse detection, rough location and size information of the defects are acquired from the whole point cloud data. Based on coarse detected boundary box containing defects, the detailed extraction step is applied to extract corresponding defects shape accurately. The feasibility of proposed method was validated by using a case to detect defects of a damaged turbine blade and the detection results can be used to generate restoration tool path. The results show that the proposed method outperforms state-of-art defects detection methods, which can reduce time by 74.03% and reduce error by 36.86%, respectively.

Effect of sodium gluconate on dispersion of polycarboxylate superplasticizer with different grafting density in side chain

Fubing Zou,Hongbo Tan,Yulin Guo,Baoguo Ma,Xingyang He,Yang Zhou 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.55 No.-

Sodium gluconate is a commonly used retarder, and the incorporation of SG has been accepted as the most efficient way to improve the basic performance of polycarboxylate superplasticizer (PCE) system in real concrete. However, this improvement cannot be always achieved, and the main reason for this uncertainty is because the interaction between PCE and SG has not completely understood. In order to gain deeper insight into this interaction, adsorption behavior and dispersion mechanism of PCE-SG system involved in two kinds of PCE with different grafting density of carboxyl groups in side chain have been investigated. Specifically, the dispersion was assessed with the fluidity of the cement paste, and adsorption behavior was estimated with total organic carbon and zeta potential. The combination between PCE and SG was characterized with conductivity, dynamic light scattering, and X-ray photoelectron spectroscopy. Finally, several models were proposed to illustrate the mechanism behind. The results show that gluconate grafted as side chain of PCE and the increase in length of PEO chain caused by addition of SG can provide contribution to dispersion. Competitive adsorption between SG and PCE would take place to reduce the dispersion, and the declining degree depends on the relative adsorption between PCE and SG. Dispersion of PCE-SG is not only dependent on added dosage of SG, but also decided by molecular structure of PCE. This result provides guidance on how to promote the basic performance of the PCE-retarder system in real engineering practice.

Periparturient stocking density affects lying and ruminating behavior and one-week-calf performance of Holstein cows

Jiang Mingming,Alugongo Gibson Maswayi,Xiao Jianxin,Li Congcong,Ma Yulin,Li Tingting,Cao Zhijun,Liu Dasen 아세아·태평양축산학회 2021 Animal Bioscience Vol.34 No.4

Objective: This study aimed to investigate the effect of stocking density on the behavior, productivity, and metabolism of periparturient Holstein cows as well as calf performance. Methods: A total of 48 periparturient cows were randomly assigned into three groups at 28 days (±3 days) before their expected calving date. The stocking densities of the groups, relative to the standard cubicle and feed bunk number, were i) 80% (13 cows), ii) 100% (16 cows), and iii) 120% (19 cows). Lying and rumination behavior was recorded using electronic data loggers and HR-Tags from d -21 (“d-” means days before calving) until the calving date, d 0. Lying time was assessed to determine the diurnal total hours spent lying per day. Rumination time was averaged in 2 hours interval periods over 24 hours during the experimental period. Results: Cows in the 80% group spent more time lying and ruminating between d -21 and d -7 and tended to ruminate more between d -14 and d 0. Calcium levels tended to be higher for cows in the 80% group, no other observable differences were found in monitored blood parameters. Moreover, 3.5% fat corrected milk and energy corrected milk yields were higher in 80% group in the first month of lactation. No other observable differences were found in the yield and composition of colostrum and milk in the first 10 months of lactation. The growth and performance of calves in the first week of life was not affected by stocking density of the dams. Conclusion: We concluded that lower stocking density may increase lying and ruminating behavior of prepartum Holstein cows. However, this did not translate into improved productivity and metabolism. Objective: This study aimed to investigate the effect of stocking density on the behavior, productivity, and metabolism of periparturient Holstein cows as well as calf performance.Methods: A total of 48 periparturient cows were randomly assigned into three groups at 28 days (±3 days) before their expected calving date. The stocking densities of the groups, relative to the standard cubicle and feed bunk number, were i) 80% (13 cows), ii) 100% (16 cows), and iii) 120% (19 cows). Lying and rumination behavior was recorded using electronic data loggers and HR-Tags from d -21 (“d-” means days before calving) until the calving date, d 0. Lying time was assessed to determine the diurnal total hours spent lying per day. Rumination time was averaged in 2 hours interval periods over 24 hours during the experimental period.Results: Cows in the 80% group spent more time lying and ruminating between d -21 and d -7 and tended to ruminate more between d -14 and d 0. Calcium levels tended to be higher for cows in the 80% group, no other observable differences were found in monitored blood parameters. Moreover, 3.5% fat corrected milk and energy corrected milk yields were higher in 80% group in the first month of lactation. No other observable differences were found in the yield and composition of colostrum and milk in the first 10 months of lactation. The growth and performance of calves in the first week of life was not affected by stocking density of the dams.Conclusion: We concluded that lower stocking density may increase lying and ruminating behavior of prepartum Holstein cows. However, this did not translate into improved productivity and metabolism.