Distribution characteristic of hydrodynamic pressure in the ballastless track crack under the train load

Shihao Cao,Rongshan Yang,Luhui Shi,Jiali Li,Xueyi Liu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.2

In the areas which have rich rain and poor drainage, there may be obvious water damage existed in the interlamination of ballastless track. The damage is mainly caused by repeated hydraulic fracturing. Aimed at this problem, the calculation model of water pressure under the train load was established on the basis of fluid-structure interaction theory, and the influence of crack geometry and train operation condition on water pressure were analyzed. The results show that, when the train is close to and far away from the location of the crack, the water pressure changes periodically under the train load, and the pressure peak occurs at the crack front. Simultaneously, the positive and negative pressure may both exist in the crack. The crack geometry affects the distribution of water pressure significantly, the value of water pressure is inversely proportional to the vertical opening of crack, and proportional to the cubic polynomial of horizontal crack depth. The water pressure increases firstly with the increase of longitudinal crack length, then decreases gradually and tends to be stable finally. The train operation condition is also an important factor affecting the distribution of water pressure, the value of water pressure is linear with the axle load, and proportional to the square of train speed. These research results will provide a hydraulic boundary condition for further study of water damage mechanism.

Structural Relationship between Motivation, Involvement, Satisfaction and Loyalty of University Basketball Participants in China

( Qiwei Yang ),( Xin Qi ),( Shihao Huang ),( Chuan Yi ),( Yinggang Chen ) 아시아스포츠융합과학회 2021 Asia Pacific Journal of Applied Sport Sciences Vol.2 No.2

PURPOSE The main purpose of this study is to test the structural relationship between motivation, involvement, satisfaction and loyalty of university basketball participants in China. METHOD The study took the participants of basketball clubs from five universities in Hunan Province as the subject. 846 questionnaires were collected and 800 were used in this study. SPSS24 and AMOS were used for this research. RESULT The results show that the motivation of basketball club’s participants has a significant positive impact on involvement, satisfaction and loyalty; Involvement has a significant positive effect on satisfaction and loyalty; Satisfaction has significant positive influence to loyalty. Finally, involvement and satisfaction can play a partial mediating role between motivation and loyalty. CONCLUSION This study verifies the structural relationship between motivation, involvement, satisfaction and loyalty of Chinese college basketball club participants. Motivation is the most important factor affecting participants’ loyalty, while involvement has the least impact on participants’ satisfaction and loyalty. Consequently, the PE management staff in university should attach more importance the motivation of participants in order to attract more students to participate in basketball activity and maintain their interests.

Numerical investigation of the critical heat fl ux in a 5 × 5 rod bundle with multi-grid

Wei Liu,Zemin Shang,Shihao Yang,Lixin Yang,Zihao Tian,Yu Liu,Xi Chen,Qian Peng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5

To improve the heat transfer efficiency of the reactor fuel assembly, it is necessary to accurately calculatethe two-phase flow boiling characteristics and the critical heat flux (CHF) in the fuel assembly. In thispaper, a Eulerian two-fluid model combined with the extended wall boiling model was used tonumerically simulate the 5 5 fuel rod bundle with spacer grids (four sets of mixing vane grids and foursets of simple support grids without mixing vanes). We calculated and analyzed 11 experimental conditions under different pressure, inlet temperature, and mass flux. After comparing the CHF and thelocation of departure from the nucleate boiling obtained by the numerical simulation with the experimental results, we confirmed the reliability of computational fluid dynamic analysis for the prediction ofthe CHF of the rod bundle and the boiling characteristics of the two-phase flow. Subsequently, weanalyzed the influence of the spacer grid and mixing vanes on the void fraction, liquid temperature, andsecondary flow distribution. The research in this article provides theoretical support for the design of fuelassemblies

Acupuncture treatment for Hashimoto's thyroiditis: An exploratory randomized controlled trial

Shanze Wang,Chao Yang,Weimei Zeng,Hongfang Tian,Shihao Du,Jiping Zhao 한국한의학연구원 2024 Integrative Medicine Research Vol.13 No.1

Background: Hashimoto's thyroiditis (HT) has a high incidence rate and unresolved clinical symptoms. Although Hand Yangming Meridian Penetrating Acupuncture has been used to treat thyroid diseases in China, there is no randomized controlled trial (RCT) on HT. Methods: This exploratory RCT aims to preliminarily evaluate the efficacy, safety, and feasibility of Hand Yangming Meridian Penetrating Acupuncture in the treatment of HT. Included subjects were randomly assigned to the acupuncture group and the waiting treatment group at a ratio of 1:1. Subjects in the acupuncture group received 16 weeks of acupuncture treatment, followed by a 16-week follow-up observation phase. Subjects in the waiting group received thyroxine supplementation for 16 weeks, followed by 16 weeks of compensation treatment. Serum thyroid peroxidase antibody (TPOab) and thyroglobulin antibody (TGab) levels were the main indicators, and Thyroid-Related Patient-Reported Outcome short form (ThyPRO-39), MOS Item Short Form Health Survey (SF-36), and Hospital Anxiety and Depression Scale (HADS) scores were also recorded. Results: In total, 58 subjects were included. After 16 weeks of treatment, there was no statistical difference in the changes in TPOab levels between the two groups, but the TGab level in the acupuncture group was significantly lower than in the waiting group (difference: −141.97 [95 % CI: −222.4 to −61.5], P = 0.011). Moreover, the total ThyPRO-39 and SF-36 scores were statistically different between the two groups (PThyPRO-39 < 0.001, PSF-36 = 0.005). There was no statistical difference in HADS between the two groups. Conclusions: Hand Yangming Meridian Penetrating Acupuncture may be safe and feasible for HT hypothyroidism to improve symptoms and reduce TGab levels. Trial registration number: This trial was registered at Acupuncture-Moxibustion Clinical Trial Registry: AMCTR-IOR-19000308 (ChiCTR1900026830, https://www.chictr.org.cn/searchprojEN.html).

A review on the risk, prevention and control of cooling water intake blockage in coastal nuclear power plants

Heshan Lin,Shuyi Zhang,Ranran Cao,Shihao Yu,Wei Bai,Rongyong Zhang,Jia Yang,Li Dai,Jianxin Chen,Yu Zhang,Hongni Xu,Kun Liu,Xinke Zhang Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.2

In recent decades, numerous instances of blockages have been reported in coastal nuclear power plants globally, leading to serious safety accidents such as power reduction, manual or automatic power loss, or shutdown of nuclear power units. Loss or shortage of cooling water may compromise the reliability of the cooling water system, thus threatening the operational safety of power plants and resulting in revenue reduction. This study provides a comprehensive review of the current state of cooling water system safety in coastal nuclear power plants worldwide and the common challenges they face, as well as the relevant research on cooling water system safety issues. The research overview and progress in investigation methods, outbreak mechanisms, prevention and control measures, and practical cases of blockages were summarized. Despite existing research, there are still many shortcomings regarding the pertinence, comprehensiveness and prospects of related research, and many problems urgently need to be solved. The most fundamental concern involves understanding the list of potential risks of blockages and their spatially distributed effects in surrounding waters. Furthermore, knowledge of the biological cycles and ecological habits of key organisms is essential for implementing risk prevention and control and for building a scientific and effective monitoring system.

Cavitation optimization of single-orifi ce plate using CFD method and neighborhood cultivation genetic algorithm

Yu Zhang,Jiang Lai,Chao He,Shihao Yang 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5

Single-orifice plate is wildly utilized in the piping system of the nuclear power plant to throttle anddepressurize the fluid of the pipeline. The cavitation induced by the single-orifice plate may cause someserious vibration of the pipeline. This study aims to find the optimal designs of the single-orifice platesthat may have weak cavitation possibilities. For this purpose, a new single-orifice plate with aconvergent-flat-divergent hole was modeled, a multi-objective optimization method was proposed tooptimize the shape of a single-orifice plate, while computational fluid dynamics method was adopted toobtain the fluid physical quantities. The reciprocal cavitation number and the developmental integralwere treated as cavitation indexes (e.g., objectives for the optimization algorithm). Two non-dominantdesigns ultimately achieved illustrated obvious reduction in the cavitation indexes at a Reynolds number Re ¼ 1 105 defined based on fluid velocity. Besides, the sensitivity analysis and temperature effectswere also performed. The results indicated that the convergent angle of the single-orifice plate dominants the cavitation behavior globally. The optimal designs of single-orifice plates result in lowerdownstream jet areas and lower upstream pressure. For a constant Reynolds number, the higher temperature of liquid water, the easier it is to undergo cavitation. Whereas there is a diametric phenomenonfor a constant fluid velocity. Moreover, the regression models were carried out to establish the mathematical relation between temperature and cavitation indexes

Toward Understanding the Adsorption And Inhibition Mechanism of Cu‑MBTA Passivation Film on Copper Surface: A Combined Experimental and DFT Investigation

Mengrui Liu,Da Yin,Baimei Tan,Fan Yang,Xiaoqin Sun,Pengcheng Gao,Shihao Zhang,Yazhen Wang 대한금속·재료학회 2021 ELECTRONIC MATERIALS LETTERS Vol.17 No.1

The adsorption and passivation reactions of 5-methyl benzotriazole (MBTA) with different copper samples (as received, citricacid treated and citric acid and KIO4treated) were studied. The experiments were characterized by contact angle measurement,potentiodynamic polarization curve, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The results showed that the adsorption behavior of MBTA on different treated surfaces was different and MBTA was preferentiallyadsorbed on the surface of citric acid treated copper. Based on the density functional theory, quantum chemicaldescriptors such as the frontier molecular orbital energies EHOMO,ELUMOand the energy gap between them, molecularelectrostatic potential, and Fukui function had been calculated and discussed. The adsorption mechanism of MBTA andcopper surface was further revealed, which had positive significance for the corrosion inhibition of copper surface in copperinterconnection CMP.