Fengxia Shi^1,2, Guangbiao Zhao^1,*, Yucai Tang¹, Haonan Zhan¹, Pengcheng Wang¹

Sound & Vibration, Vol.58, pp. 101-117, 2024, DOI:10.32604/sv.2024.047082

Abstract In order to study the effect of splitter blades on the internal and external sound field of the hydraulic turbine, the paper chose a centrifugal pump with a specific speed n_s = 33 reversed as a hydraulic turbine as the research object, and added the short blades on the original impeller to form a new splitter impeller. Based on the Re-Normalization Group (RNG) k-ε turbulence model to conduct numerical simulation for the hydraulic turbine, this thesis calculated the internal and external acoustic field by means of the acoustic boundary element (BEM) and finite element (FEM) and analyzed the noise radiation… More >

Yujie Duan¹, Jianguo Liang^1,*, Jianglin Liu¹, Haifeng Gao¹, Yinhui Li², Jinzhu Zhang¹, Xinyu Wen³

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 1239-1261, 2024, DOI:10.32604/cmes.2023.044400

Abstract In the fiber winding process, strong disturbance, uncertainty, strong coupling, and fiber friction complicate the winding constant tension control. In order to effectively reduce the influence of these problems on the tension output, this paper proposed a tension fluctuation rejection strategy based on feedforward compensation. In addition to the bias harmonic curve of the unknown state, the tension fluctuation also contains the influence of bounded noise. A tension fluctuation observer (TFO) is designed to cancel the uncertain periodic signal, in which the frequency generator is used to estimate the critical parameter information. Then, the fluctuation signal is reconstructed by a… More >

L. Cheng^a , Y. L. Zhang^a,† , J. F. Li^b

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-7, 2022, DOI:10.5098/hmt.19.32

Abstract The internal characteristics during rotational speed fluctuation have an important influence on centrifugal pump to avoid or utilize its transient performance. In this paper, a circulation piping system that includes a low-specific-speed centrifugal pump is established to study the energy distribution characteristics in a centrifugal pump during speed fluctuation. The unsteady flow in the entire system is numerically calculated with a user-defined function, the sliding grid method, and the RNG k-ε turbulence model. Then, the energy distribution of the transient flow field in the centrifugal pump model during speed fluctuation is diagnosed with vortex dynamics by using flow section and… More >

Zixiong Wang, Qiuying Chen, Sang-Joon Lee^*

CMC-Computers, Materials & Continua, Vol.75, No.2, pp. 2443-2459, 2023, DOI:10.32604/cmc.2023.037553

Abstract The rapid expansion of the non-fungible token (NFT) market has attracted many investors. However, studies on the NFT price fluctuations have been relatively limited. To date, the machine learning approach has not been used to demonstrate a specific error in NFT sale price fluctuation prediction. The aim of this study was to develop a prediction model for NFT price fluctuations using the NFT trading information obtained from OpenSea, the world’s largest NFT marketplace. We used Python programs to collect data and summarized them as: NFT information, collection information, and related account information. AdaBoost and Random Forest (RF) algorithms were employed… More >

Guodong Liu^1,2,*, Zhijun Zhou¹, Shiqiang Xu¹, Wenjing Mi²

CMES-Computer Modeling in Engineering & Sciences, Vol.133, No.2, pp. 351-375, 2022, DOI:10.32604/cmes.2022.020335

Abstract Water level variations have caused numerous dam slope collapse disasters around the world, illustrating the large influence of water level fluctuations on dam slopes. The required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil–water characteristic curve (SWCC) on the stability of the upstream dam slope. The results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC, which would be more evident… More >

Magdalini Ntetsika, Panayiotis Papadopoulos^*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1243-1258, 2021, DOI:10.32604/cmes.2021.017404

Abstract A new and computationally efficient version of the immersed boundary method, which is combined with the coarse-graining method, is introduced for modeling inextensible filaments immersed in low-Reynolds number flows. This is used to represent actin biopolymers, which are constituent elements of the cytoskeleton, a complex network-like structure that plays a fundamental role in shape morphology. An extension of the traditional immersed boundary method to include a stochastic stress tensor is also proposed in order to model the thermal fluctuations in the fluid at smaller scales. By way of validation, the response of a single, massless, inextensible semiflexible filament immersed in… More >

Emad H. El-Zohri¹, Hegazy Rezk^2,3,*, Basem Alamri⁴, Hamdy A. Ziedan⁵

Intelligent Automation & Soft Computing, Vol.30, No.1, pp. 201-213, 2021, DOI:10.32604/iasc.2021.018700

Abstract Microgrids are hybrid power systems that consist of several distributed generation resources and local loads that can supply electrical power to remote or specific areas. The integration of microgrids with the utility network is one of the most recent technologies developed in countries like Egypt. One area of study is how the integration of smart microgrids and utility systems can be used to solve power quality problems such as voltage sags, increased use of distributed generators, deep energy, and power loss. This paper is aimed at investigating a possible solution to some common and dangerous power quality issues associated with… More >

Tian Liwei^1,2,*, Feng Li¹, Sun Yu³, Guo Yuankai⁴

Intelligent Automation & Soft Computing, Vol.29, No.3, pp. 855-868, 2021, DOI:10.32604/iasc.2021.016805

Abstract The prediction of the “ups and downs” of stock market prices is one of the important undertakings of the financial market. Since accurate prediction helps foster considerable economic benefits, stock market prediction has attracted significant interest by both investors and researchers. Efforts into building an accurate, stable and effective model to predict stock prices’ movements have been proliferating at a fast pace, to meet such a challenge. Firstly, this paper uses a correlation analysis to analyze the attributes of a stock dataset, processing missing values, determining the data attributes to be retained data, then divide it in a training set… More >

Wenhui Zhao¹, Yibo Yin^1,*, Lu Mao², Konglu Zhong³, Guanghui Yuan⁴, Hai Huang⁵, Yige Yang⁶

Energy Engineering, Vol.118, No.4, pp. 1009-1026, 2021, DOI:10.32604/EE.2021.014650

Abstract Changes in the energy price system will determine the direction of evolution of the energy industry structure. As a country where coal is the dominant energy source, what is the effect of coal price fluctuations on China’s industry development costs and energy consumption structure? To investigate this problem, this paper utilized an economy–energy–environment computable general equilibrium model. In this study, four aspects were analyzed: Energy supply side, proportion of renewable energy consumption, macroeconomy, and changes in CO₂ emissions. The results of this study show that an increase of 10%–20% in coal prices contributes to a shift into using renewable energy,… More >

Misook Seo¹, In-Kyung Song², Hye-Mee Kwon², Byungdoo Andrew Lee², Won-Jung Shin^2,*

Congenital Heart Disease, Vol.16, No.2, pp. 123-136, 2021, DOI:10.32604/CHD.2021.012626

Abstract Background: In patients with cyanotic congenital heart disease (CHD), cerebral oxygenation may be maintained by elevations in hematocrit (Hct). Hemodilution accompanying cardiopulmonary bypass (CPB), however, can disrupt cerebral oxygen balance, leading to fluctuations in cerebral oxygen saturation (ScO₂). The present study investigated the effects of Hct changes on the fluctuation of ScO₂ during CPB in cyanotic CHD using performance measurement (PM). Methods: Children with CHD (51 acyanotic and 46 cyanotic) who had undergone cardiac surgery using CPB were enrolled. Median performance error (MDPE), median absolute performance error (MDAPE), and wobble parameters of ScO₂ were calculated before (reference value), during, and… More >