Mathematical Model Relating Dynamic Dewatering Process of Fresh Mortar and Its Composition

Tao Ji,Xiaoying Zhang,Xiong Zhang,Yong-juan Zhang,Caiyong Gu,Weihua Li 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

The composition and properties of raw materials have significant influences on water retention capacity of mortar, but the basic origin remains unclear. To clarify the movement of water inside mortar and the mechanism of water retention, the dynamic dewatering experiment was designed and the mathematical model describing the dewatering process of mortar was set up in this work. The model proved to be effective according to the results from dynamic dewatering experiment. The study demonstrated that capillary gradual contraction model is suitable for describing early dewatering process of fresh mortar and the parameters in the dewatering equation are relevant to the properties of raw materials, which certify that the model is of physical significance. Moreover, influencing factors such as water properties and binding materials properties were obtained and their relationship with water retention of mortar were discussed theoretically based on capillary gradual contraction model.

MiR-26a promotes apoptosis of porcine granulosa cells by targeting the 3β-hydroxysteroid-Δ24-reductase gene

Zhang, Xiaodong,Tao, Qiangqiang,Shang, Jinnan,Xu, Yiliang,Zhang, Liang,Ma, Yingchun,Zhu, Weihua,Yang, Min,Ding, Yueyun,Yin, Zongjun Asian Australasian Association of Animal Productio 2020 Animal Bioscience Vol.33 No.4

Objective: Apoptosis of ovarian granulosa cells (GCs) affects mammalian follicular development and fecundity. This study aimed to explore the regulatory relationship between microRNA-26a (miR-26a) and the 3β-hydroxysteroid-Δ24-reductase gene (DHCR24) gene in porcine follicular granular cells (pGCs), and to provide empirical data for the development of methods to improve the reproductive capacity of pigs. Methods: The pGCs were transfected with miR-26a mimic, miR-26a inhibitor and DHCR24-siRNA in vitro. The cell apoptosis rate of pGCs was detected by the flow cytometry. The secretion levels of estradiol (E2) and progesterone (P) in pGCs were detected by enzyme-linked immunosorbent assay. Double luciferase validation system was used to detect the binding sites between miR-26a and DHCR24 3'-UTR region. Qualitative real-time polymerase chain reaction and Western blotting were used to verify the DHCR24 mRNA and protein expression in pGCs, respectively, after transfecting with miR-26a mimic and miR-26a inhibitor. Results: Results showed that enhancement of miR-26a promoted apoptosis, and inhibited E2 and P secretion in pGCs. Meanwhile, inhibition of DHCR24 also upregulated the Caspase-3 expression, reduced the BCL-2 expression, promoted pGCs apoptosis, and inhibited E2 and P secretion in pGCs. There were the binding sites of miR-26a located within DHCR24 3'-UTR. Up-regulation of miR-26a inhibited DHCR24 mRNA and protein expression in pGCs. Conclusion: This study demonstrates that miR-26a can promote cell apoptosis and inhibit E2 and P secretion by inhibiting the expression of DHCR24 in pGCs.

Optimizing the Imaging Protocol for Ex Vivo Coronary Artery Wall Using High-Resolution MRI: An Experimental Study on Porcine and Human

Jiong Yang,Tao Li,Xiaoming Cui,Weihua Zhou,Xin Li,Xinwu Zhang 대한영상의학회 2013 Korean Journal of Radiology Vol.14 No.4

Objective: To optimize the MR imaging protocol for coronary arterial wall depiction in vitro and characterize the coronary atherosclerotic plaques. Materials and Methods: MRI examination was prospectively performed in ten porcine hearts in order to optimize the MR imaging protocol. Various surface coils were used for coronary arterial wall imaging with the same parameters. Then, the image parameters were further optimized for high-resolution coronary wall imaging. The signal-noise ratio (SNR) and contrast-noise ratio (CNR) of images were measured. Finally, 8 human cadaver hearts with coronary atherosclerotic plaques were prospectively performed with MRI examination using optimized protocol in order to characterize the coronary atherosclerotic plaques. Results: The SNR and CNR of MR image with temporomandibular coil were the highest of various surface coils. High-resolution and high SNR and CNR for ex vivo coronary artery wall depiction can be achieved using temporomandibular coil with 512 x 512 in matrix. Compared with histopathology, the sensitivity and specificity of MRI for identifying advanced plaques were: type IV-V (lipid, necrosis, fibrosis), 94% and 95%; type VI (hemorrhage), 100% and 98%; type VII (calcification), 91% and 100%; and type VIII (fibrosis without lipid core), 100% and 98%, respectively. Conclusion: Temporomandibular coil appears to be dramatically superior to eight-channel head coil and knee coil for ex vivo coronary artery wall imaging, providing higher spatial resolution and improved the SNR. Ex vivo high-resolution MRI has capability to distinguish human coronary atherosclerotic plaque compositions and accurately classify advanced plaques.

A rolling bearing fault diagnosis strategy based on improved multiscale permutation entropy and least squares SVM

Yongjian Li,Weihua Zhang,Qing Xiong,Dabing Luo,Guiming Mei,Tao Zhang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

A novel rolling bearing fault diagnosis strategy is proposed based on Improved multiscale permutation entropy (IMPE), Laplacianscore (LS) and Least squares support vector machine-Quantum behaved particle swarm optimization (QPSO-LSSVM). Entropy-basedconcepts have attracted attention recently within the domain of physiological signals and vibration data collected from human body orrotating machines. IMPE, which was developed to reduce the variability of entropy estimation in time series, was used to obtain moreprecise and reliable values in rolling element bearing vibration signals. The extracted features were then refined by LS approach to form anew feature vector containing main unique information. By constructing the fault feature, the effective characteristic vector was input toQPSO-LSSVM classifier to distinguish the health status of rolling bearings. The comparative test results indicate that the proposed methodologyled to significant improvements in bearing defect identification.

Uncertainty Analysis of Dynamic Thermal Rating of Overhead Transmission Line

Xing Zhou,Yanling Wang,Xiaofeng Zhou,Weihua Tao,Zhiqiang Niu,Ailing Qu 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.2

Dynamic thermal rating of the overhead transmission lines is affected by many uncertain factors. The ambienttemperature, wind speed and wind direction are the main sources of uncertainty. Measurement uncertainty isan important parameter to evaluate the reliability of measurement results. This paper presents the uncertaintyanalysis based on Monte Carlo. On the basis of establishing the mathematical model and setting the probabilitydensity function of the input parameter value, the probability density function of the output value is determinedby probability distribution random sampling. Through the calculation and analysis of the transient thermalbalance equation and the steady- state thermal balance equation, the steady-state current carrying capacity, thetransient current carrying capacity, the standard uncertainty and the probability distribution of the minimumand maximum values of the conductor under 95% confidence interval are obtained. The simulation resultsindicate that Monte Carlo method can decrease the computational complexity, speed up the calculation, andincrease the validity and reliability of the uncertainty evaluation.

Uncertainty Analysis of Dynamic Thermal Rating of Overhead Transmission Line

Zhou, Xing,Wang, Yanling,Zhou, Xiaofeng,Tao, Weihua,Niu, Zhiqiang,Qu, Ailing Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.2

Dynamic thermal rating of the overhead transmission lines is affected by many uncertain factors. The ambient temperature, wind speed and wind direction are the main sources of uncertainty. Measurement uncertainty is an important parameter to evaluate the reliability of measurement results. This paper presents the uncertainty analysis based on Monte Carlo. On the basis of establishing the mathematical model and setting the probability density function of the input parameter value, the probability density function of the output value is determined by probability distribution random sampling. Through the calculation and analysis of the transient thermal balance equation and the steady- state thermal balance equation, the steady-state current carrying capacity, the transient current carrying capacity, the standard uncertainty and the probability distribution of the minimum and maximum values of the conductor under 95% confidence interval are obtained. The simulation results indicate that Monte Carlo method can decrease the computational complexity, speed up the calculation, and increase the validity and reliability of the uncertainty evaluation.

Study on Thermal Load Capacity of Transmission Line Based on IEEE Standard

Song, Fan,Wang, Yanling,Zhao, Lei,Qin, Kun,Liang, Likai,Yin, Zhijun,Tao, Weihua Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.3

With the sustained and rapid development of new energy sources, the demand for electric energy is increasing day by day. However, China's energy distribution is not balanced, and the construction of transmission lines is in a serious lag behind the improvement of generating capacity. So there is an urgent need to increase the utilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowable operating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the static thermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique can improve the utilization of transmission capacity to a certain extent. In this paper, the meteorological parameters affecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation of overhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-year actual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under given confidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing the relevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basis for the wind power grid integration and grid intelligence. The results show that the thermal load potential of transmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving the absorptive capacity of power grid.

Experimental dynamic performance of an Aluminium-MRE shallow shell

Tanju Yildirim,Jiawei Zhang,Guru Prakash Neupane,Yuechuan Tao,Jiang Bingnong,Weihua Li 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.1

The nonlinear dynamics of a directly forced clamped-clamped-free-free magneto-rheological elastomer (MRE) sandwich shell has been experimentally investigated. Experiments have been conducted on an aluminium shallow shell (shell A) and an MRE-aluminium sandwich shallow shell with single curvature (shell B). An electrodynamic shaker has been used to directly force shells A and B in the vicinity of their fundamental resonance frequency; a laser displacement sensor has been used to measure the vibration amplitude to construct the frequency-response curves. It was observed that for an aluminium shell (shell A), that at small forcing amplitudes, a weak softening-type nonlinear behaviour was observed, however, at higher forcing amplitudes the nonlinear dynamical behaviour shifted and a strong hardening-type response occurred. For the MRE shell (shell B), the effect of forcing amplitude showed softening at low magnetic fields and hardening for medium magnetic fields; it was also observed the mono-curved MRE sandwich shell changed dynamics to quasiperiodic displacement at some frequencies, from a periodic displacement. The presence of a magnetic field, initial curvature, and forcing amplitude has significant qualitative and quantitative effects on the nonlinear dynamical response of a mono curved MRE sandwich shell.

Study on Thermal Load Capacity of Transmission Line Based on IEEE Standard

Fan Song,Yanling Wang,Lei Zhao,Kun Qin,Likai Liang,Zhijun Yin,Weihua Tao 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.3

With the sustained and rapid development of new energy sources, the demand for electric energy is increasingday by day. However, China’s energy distribution is not balanced, and the construction of transmission lines isin a serious lag behind the improvement of generating capacity. So there is an urgent need to increase theutilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowableoperating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the staticthermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique canimprove the utilization of transmission capacity to a certain extent. In this paper, the meteorological parametersaffecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation ofoverhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-yearactual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under givenconfidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing therelevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basisfor the wind power grid integration and grid intelligence. The results show that the thermal load potential oftransmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving theabsorptive capacity of power grid.

The impacts of resveratrol on the retinal degeneration in a rat model of retinitis pigmentosa induced by alkylation: an in-vivo study

Weiming Yan,Yan Sun,Yutong Wang,Wangjiao Liang,Yuxin Xia,Weihua Yan,Meizhu Chen,Tao Chen,Dongliang Li 한국통합생물학회 2023 Animal cells and systems Vol.27 No.1

Upregulation of Sirtuin Type 1 (SIRT1), a nicotinamide adeninedinucleotide (NAD+)-dependentdeacetylase, has been proved to protect against ample ocular diseases, while its effect onretinitis pigmentosa (RP) has not been illustrated. The study was aimed to explore the impactsof resveratrol (RSV), a SIRT1 activator, on the photoreceptor degeneration in a rat model of RPinduced by N-methyl-N-nitrosourea (MNU), an alkylation. The rats were induced RP phenotypesvia the intraperitoneal injection of MNU. The electroretinogram was conducted and revealedthat RSV could not prevent the decline of retinal function in the RP rats. The optical coherencetomography (OCT) and the retinal histological examination were performed and showed thatthe reduced thickness of the outer nuclear layer (ONL) was not preserved by RSV intervention. The immunostaining technique was applied. Afther the MNU administration, the number of theapoptotic photoreceptors in the ONL throughout the retinasand the number of microglia cellspresent among the outer part throughout the retinas were not significantly reduced by RSV. Western blotting was also performed. The data showed that the level of SIRT1 protein wasdecreased after MNU administration, while RSV was not able to obviously alleviate thedownregulation. Our data together indicated that RSV was not able to rescue thephotoreceptor degeneration in the MNU-induced RP rats, which might be due to the MNUinducedconsumption of the NAD+.