Experimental investigation on flow field around a flapping plate with single degree of freedom

Hanyu Wang,Chuan Lu,Wenhai Qu,Jinbiao Xiong Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

Undesirable flapping motion of discs can cause the failure of swing check valves in nuclear passive safety systems. Time-resolved particle image velocimetry (PIV) was employed to investigate the flow characteristics around a free-to-rotate plate and the motion response, with the Reynolds numbers, based on the hydraulic diameter of the channel, from 1.32 × 10⁴ to 3.95 × 10⁴. Appreciable flapping motion (±3.52°) appeared at the Reynolds number of 2.6 × 10⁴ with the frequency of 5.08 Hz. In the low-Reynolds-number case, the plate showed negligible flapping. In the high-Reynolds-number case, the deflection angle increased with reduced flapping amplitude. The torque from the fluid determined the flapping amplitude. In the low-Reynolds-number case, Karman vortices were absent. With increasing Reynolds numbers, Karman vortices developed behind the plate with larger deflection angles. Strong interaction between the wake flow from the leading and trailing edge of the plate was observed. Based on power spectrum density (PSD) analysis, the vortex shedding frequency coincided with the flapping frequency, and the amplitude was positively correlated to the strength of the vortices. Proper orthogonal decomposition (POD) modes evince that, in the case of appreciable motion, coherent structures exhibited a larger spatial scale, enhancing the magnitude of the external torque on the plate.

Horizontal and vertical crossover of sine cosine algorithm with quick moves for optimization and feature selection

Hu Hanyu,Shan Weifeng,Tang Yixiang,Heidari Ali Asghar,Chen Huiling,Liu Haijun,Wang Maofa,Escorcia-Gutierrez José,Mansour Romany F,Chen Jun 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.6

The sine cosine algorithm (SCA) is a metaheuristic algorithm proposed in recent years that does not resort to nature-related metaphors but explores and exploits the search space with the help of two simple mathematical functions of sine and cosine. SCA has fewer parameters and a simple structure and is widely used in various fields. However, it tends to fall into local optimality because it does not have a well-balanced exploitation and exploration phase. Therefore, in this paper, a new, improved SCA algorithm (QCSCA) is proposed to improve the performance of the algorithm by introducing a quick move mechanism and a crisscross mechanism to SCA and adaptively improving one of the parameters. To verify the effectiveness of QCSCA, comparison experiments with some conventional metaheuristic algorithms, advanced metaheuristic algorithms, and SCA variants are conducted on IEEE CEC2017 and CEC2013. The experimental results show a significant improvement in the convergence speed and the ability to jump out of the local optimum of the QCSCA. The scalability of the algorithm is verified in the benchmark function. In addition, QCSCA is applied to 14 real-world datasets from the UCI machine learning database for selecting a subset of near-optimal features, and the experimental results show that QCSCA is still very competitive in feature selection (FS) compared to similar algorithms. Our experimental results and analysis show that QCSCA is an effective method for solving global optimization problems and FS problems.

Rapid Microwave Irradiation Synthesis and Photoelectrochemical Performance of Cu3BiS3 nanoparticles

Wei Wang,Guowei Zhi,Liu Liu,Yujie  Fei,QinYang Sheng,Yushi Shi,Hanyu Yao,Hongqiang Qian 대한금속·재료학회 2022 ELECTRONIC MATERIALS LETTERS Vol.18 No.6

A photocatalytic material with high performance and low cost plays a decisive role in the industrialization of photocatalytichydrogen evolution. In this work, Cu3BiS3 nanoparticles were successfully synthesized by the microwave irradiationmethod, and the formation mechanism of Cu3BiS3 was studied. The Cu3BiS3 was a nanorod structure with 122 nm diameterand 41 nm length. The band gap was 1.31 eV and the EVB was located at 0.15 eV from the Mott-Schottky analysis. The Cu3BiS3 electrode exhibited an excellent HER performance with an onset potential of 870 mV, a Tafel slope of 251.07mV/dec. And the charge transfer resistance (Rct) of Cu3BiS3 electrode was 7.2 Ω. The electrode also revealed the goodphotoelectric response ability. The electrode also revealed the good photoelectric response ability and good stability bytime course of the photocurrents. This work provided a fast, low-cost method to prepare the Cu3BiS3 for photocatalysiswater splitting.

Experimental investigation of amplitude-dependent self-excited aerodynamic forces on a 5:1 rectangular cylinder

Qi Wang,Bo Wu,Haili Liao,Hanyu Mei 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.34 No.1

This paper presents a study on amplitude-dependent self-excited aerodynamic forces of a 5:1 rectangular cylinder through free vibration wind tunnel test. The sectional model was spring-supported in a single degree of freedom (SDOF) in torsion, and it is found that the amplitude of the free vibration cylinder model was not divergent in the post-flutter stage and was instead of various stable amplitudes varying with the wind speed. The amplitude-dependent aerodynamic damping is determined using Hilbert Transform of response time histories at different wind speeds in a smooth flow. An approach is proposed to extract aerodynamic derivatives as nonlinear functions of the amplitude of torsional motion at various reduced wind speeds. The results show that the magnitude of A2*, which is related to the negative aerodynamic damping, increases with increasing wind speed but decreases with vibration amplitude, and the magnitude of A3* also increases with increasing wind speed but keeps stable with the changing amplitude. The amplitude-dependent aerodynamic derivatives derived from the tests can also be used to estimate the post-flutter response of 5:1 rectangular cylinders with different dynamic parameters via traditional flutter analysis.

Influence of synergistic effect of phosphate on corrosion resistance of self-assembled superhydrophobic composite film on 6061 aluminum alloy surfaces

Likui Wang,Shichen Lu,Feng Xie,Hanyu Liu,Jiaping Li,Wei Shang,Zhe Zhang,Yuqing Wen 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.128 No.-

Aluminum (Al) alloys are used in a wide range of applications due to their advantages. However, theexisting corrosion protection methods have insufficient protection ability and cannot achieve longtermprotection. In this paper, reactive protective film on the surface of aluminum alloys using 1-hydroxyethyl-1,1-diphosphonic acid (HEDP) molecules. Then, Lauric acid/Graphene (LA/rGO) film is usedto prepared on the surface of HEDP film. SEM, XRD, EDS, Raman, XPS and WCA were conducted to analyzephysical and chemical features of coatings. The total resistance of the film reaches 1.0 1020 Xcm2, in asalt spray test using 5wt% NaCl as the corrosion medium, corrosion spots appeared on day 28 with a corrosioninhibition efficiency of 99.99%. Theoretical studies with quantum chemical calculations haveshown that HEDP/LA/rGO composite films can be adsorbed on Al alloy surfaces through P-O-Al and PO-C chemical bonding. The influence of phosphate synergistic effect on the corrosion resistance of theself-assembled superhydrophobic composite film on the surface of 6061 aluminum alloy is discussed. This study presents a scientific and innovative design concept to develop coatings with excellent corrosionprotection for aluminum alloy, and then extend their application to certain areas.

Prevalence and risk factors of colorectal cancer in Asia

Martin CS Wong,Hanyue Ding,Jingxuan Wang,Paul SF Chan,Junjie Huang 대한장연구학회 2019 Intestinal Research Vol.17 No.3

Globally, colorectal cancer (CRC) is a substantial public health burden, and it is increasingly affecting populations in Asian countries. The overall prevalence of CRC is reported to be low in Asia when compared with that in Western nations, yet it had the highest number of prevalent cases. This review described the prevalence of CRC in Asia according to the International Agency for Research on Cancer from World Health Organization (WHO) database and summarized its major risk factors. Non-modifiable factors include genetic factors, ethnicity, age, gender, family history and body height; smoking, alcohol drinking, weight, Westernized diet, physical inactivity, chronic diseases and microbiota were involved in environmental factors. These risk factors were separately discussed in this review according to published literature from Asian countries. CRC screening has been playing an important role in reducing its disease burden. Some recommendations on its screening practices have been formulated in guidelines for Asia Pacific countries.

Failure analysis for hoisting wire ropes with local accumulated broken wire damage on the surface

Ping Zhou,Gongbo Zhou,Lianfeng Han,Xiaodong Yan,Hanyu Wang,Zhenzhi He 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

Surface broken wire (BW) damage to hoisting steel wire ropes (SWR) is unavoidable during the service process, and it continues to accumulate locally during the evolution process. The specific influence analysis of the surface damage with local cumulative BWs on the performance of the hoisting SWR is insufficient at present, which seriously affects the safety of the rope system. In this paper, a failure analysis method for the state of surface cumulative BW rope based on the integration of finite element (FE) and mechanical tension is proposed. First, a method for creating an FE model of surface BW damage is presented, and the stress-strain distribution features of damaged section under tensile load are revealed. Then, the residual mechanical strength of SWR under local cumulative BW damage is determined by performing a tensile test. Finally, based on the analysis of FE and breaking behavior, combined with the regulations, the state of the damaged SWR is comprehensively evaluated. The results show that the breaking position of the SWR under mechanical tension is the maximum stress distribution in the simulation analysis, which verifies the consistency between the simulation and the experiment; and the accumulation degree and distribution of local BW affect the residual mechanical strength of the SWR. This method explores the influence of different degrees of local BW damage on the mechanical properties of the SWR, which provides a direct basis for the non-destructive evaluation of the SWR state.