bluuebunny/crossref_metadata_2025_split huggingface dataset:
High velocity impact on generic CFRP blade specimen: baseline free method for impact localisation and damage assessment on complex structures
Authors: Cuomo Stefano , Bätzel Tim , Modler Niels , Hornig Andreas , Meo Michele 
Published: May 2022

AbstractNowadays components made of unidirectional composite materials are largely diffused in many engineering fields, such as automotive, railways, marine and aerospace. Main drawback of this class of materials lies in their low out-of-plane properties making them very sensible to impulsive loads such as impact events. After a collision with an external object, composites structures could be affected by damage, sometimes not visible from visual inspections (barely visible damage) hence with detrimental consequences on structure resistance and strength. Therefore, it is fundamental in terms of safety to continuously assess the healthy state of structures during their life and determine whether an impact event has occurred and if it caused damage or not. This work proposes a baseline free methodology to determine the coordinates of very high velocity impact on complex structures and evaluate if damage has occurred during the impact by only acquiring signal during the impact event. The technique overcomes the common limitations of previous technique presented in literature, i.e.a prioriknowledge of mechanical properties, vibration response analysis, wave propagation direction dependency, sensor locations. The routine developed is based first on the estimation of the power of the acoustic emission generated by impact events, at sensors location, then the power information through the entire structure is reconstructed exploiting radial basis function network. The actual impact estimation is finally obtained using a weighted method. Furthermore, damage assessment is conducted with a novel method based on Hilbert–Huang transform and mode decomposition. Experimental tests were performed on a generic carbon fibre reinforced polymers blade specimen with a complex stacking sequence and embedded sensors. Two test configurations at different velocities were considered: one at 90 m s−1and one at 190 m s−1. Before and afterwards the actual impact tests, the blade was excited as well with a modal hammer (pre and post impact). The results from the impact analysis highlighted the validity and reliability of the proposed method, with a high level of accuracy in terms of impact localisation estimation, and qualitative integrity state was effectively evaluated.
The power threshold of H-mode access in mixed hydrogen–tritium and pure tritium plasmas at JET with ITER-like wall
Authors: Birkenmeier G. , Solano E.R. , Lerche E. , Taylor D. , Gallart D. , Mantsinen M.J. , Delabie E. , Carvalho I.S. , Carvalho P. , Pawelec E. , Hillesheim J.C. , Parra Diaz F. , Silva C. , Aleiferis S. , Bernardo J. , Boboc A. , Douai D. , Litherland-Smith E. , Henriques R. , Kirov K.K. , Maggi C.F. , Mailloux J. , Maslov M. , Rimini F.G. , Silburn S.A. , Sirén P. , Weisen H. 
Published: May 2022

Abstract
The heating power to access the high confinement mode (H-mode), P
LH, scales approximately inversely with the isotope mass of the main ion plasma species as found in (protonic) hydrogen, deuterium and tritium plasmas in many fusion facilities over the last decades. In first dedicated L–H transition experiments at the Joint European Torus (JET) tokamak facility with the ITER-like wall (ILW), the power threshold, P
LH, was studied systematically in plasmas of pure tritium and hydrogen–tritium mixtures at a magnetic field of 1.8 T and a plasma current of 1.7 MA in order to assess whether this scaling still holds in a metallic wall device. The measured power thresholds, P
LH, in Ohmically heated tritium plasmas agree well with the expected isotope scaling for metallic walls and the lowest power threshold was found in Ohmic phases at low density. The measured power thresholds in ion cyclotron heated plasmas of pure tritium or hydrogen–tritium mixtures are significantly higher than the expected isotope mass scaling due to higher radiation levels. However, when the radiated power is taken into account, the ion cyclotron heated plasmas exhibit similar power thresholds as a neutral beam heated plasma, and are close to the scaling. The tritium plasmas in this study tended to higher electron heating fractions and, when heated with ion cyclotron waves, to relatively higher radiation fractions compared to other isotopes potentially impeding access to sustained H-modes.
Mathematical verification of dual-frequency characteristic in rotating cavitations
Authors: Yoon Youngkuk , Song Seung Jin 
Published: May 2022

Abstract
Unlike other common rotating instabilities such as rotating stall, unsteady pressure measurement of inducer rotating cavitation had shown dual-frequency characteristic: the Fourier transformation of the pressure signals showed two distinct frequency peaks. It was assumed that the dual-frequency characteristic is originated from the non-linear interaction between the actual oscillation frequency of the cavity and the blade passing frequency. However, the manifestation of the rotating cavitation as dual-frequency peaks has only been observed experimentally and yet explained theoretically. Thus, based on the oscillating nature of the rotating cavitation, the present paper provides mathematical framework to show that the dual-frequency characteristics can be derived from the phase-locked oscillating cavities. The rotating cavitation is first expressed with respect to the rotating frame, and then transformed into the stationary frame to determine frequency peaks. The predicted frequency peak of the rotating cavitation unsteady pressure signal well captures the experimental results from previous research.
Numerical investigation of rotating cavitation in a three blade inducer
Authors: Mu Zhendong , Chen Tairan , Liang Wendong 
Published: May 2022

Abstract
The rotating cavitation in the inducer has a crucial influence on the safety and operation efficiency of heavy-duty liquid rocket engines. The objective of this paper is to investigate the rotating cavitation behaviors in the inducer and the influence of thermodynamic effects on the inducer performance, under a wide range of operating conditions. The cavitating flows through a three-blade inducer with room temperature water and liquid oxygen was numerically investigated. The numerical approaches considering the thermal effects are verified by the experimental data. The results show that as the inlet pressure decreases, cavity firstly grows near the blade tip clearance and extends to the blade surface. As the pressure further decreases, the cavity volume becomes larger and blocks the entire flows passage. It causes the dramatic drop of head performance of inducer. A periodical evolution of cavity volume in each blade was analyzed. The characteristic frequency and radial force amplitude of rotating cavitation generally agreed with the experimental measurements. The results show that the variation of radial force on the hub is related to the evolution of the cavity area. At the same cavitation number and flow rate coefficient, the breakdown point of liquid oxygen is later than that of room temperature water due to the thermodynamic effects.
Numerical analysis of the cavitating flow in an axial flow waterjet pump with special emphasis on the tip leakage flow and tip leakage vortex
Authors: Zhao Xiaoyang , Chen Tairan , Huang Biao , Wang Guoyu 
Published: May 2022

Abstract
Due to the structural design requirements, tip leakage flow is a common phenomenon in the field of axial flow rotating machinery. The tip leakage flow interacts with the mainstream and induce complex tip leakage vortex. When the local pressure drops to the saturation pressure, cavitation may occur in flow passage and the vortex core. The tip leakage cavitating flow has a huge effect on the flow stability, which may reduce the efficiency of the waterjet pump. In the present study, Zwart cavitation model and SST k-ω turbulence model are employed to simulate the cavitating flow. The new proposed Liutex criterion has been used to capture the vortex structures in the flow passage and the tip gap. The vorticity transport equation in cylindrical coordinates is also used to discuss the variation tendency of the vorticity in the vicinity of the gap region under cavitation condition. The evolution of the cavitation is proved to be vital important for the formation and the breakdown of the tip leakage vortex. By analyzing the vorticity transport equation, the stretching term is shown to be the decisive factor.
Internal flow characteristics of water-ring of pump-turbine during pump mode’s starting-up
Authors: Zhang Fei , Chen Shuai , Chen Zhenmu , Zhu Baoshan 
Published: May 2022

Abstract
Synchronous condenser mode is an important process for the conversion of pumped storage units. The compressed air is injected into the runner passage to reduce the input power under the condition of pump mode’s starting-up. In this study, a pump turbine model with medium specific speed was utilized for investigating the internal flow characteristic of water-ring. Unsteady state analysis was conducted with the turbulence model of RNG k-ε and multiphase flow model of VOF. The internal flow of the vaneless and the tandem cascade spaces was examined under the water-ring phenomenon. The results show that the air and water form an interface in the vaneless space obviously and a certain thickness of water-ring was formed. Water-ring prevents the air from runner passage into casing, which play a sealing role.
Aeroacoustic simulation of broadband sound generated from a cross-flow fan using immersed boundary-lattice Boltzmann method
Authors: Kusano K , Furukawa M , Sakoda K , Fukui T 
Published: May 2022

Abstract
In this study, we investigated the capability of the immersed boundary-lattice Boltzmann method (IB-LBM) in simulating the broadband sound generated from a cross-flow fan. The present method is based on the lattice Boltzmann equation with the D3Q27 particle velocity model, and the cascaded collision operator was used to stably simulate high-Reynolds-number flows. Furthermore, the direct-forcing approach was used to consider rotating blades in the regular lattice. To capture turbulence eddies in the rotor, we used a high-resolution grid that contained approximately 340 million nodes. The simulation successfully captured the fundamental flow features of the cross-flow fan such as the eccentric vortex, and the simulation results were consistent with the experimental results in terms of the time-averaged velocity distribution at the outlet of the fan. In addition, by resolving turbulent eddies in the impeller, the simulation successfully predicted the broadband sound spectrum in the frequency range of 2 kHz or less.
The relation between internal flow and loss mechanism of unshrouded runners
Authors: Nagata Shunsuke , Irie Tatsuya , Miyagawa Kazuyoshi 
Published: May 2022

Abstract
High efficiency, low-cost, and reliable hydraulic turbines are in high demand for hydroelectric power generation, especially in medium and small-scale power plants. The authors’ laboratory has been developing unshrouded, i.e., band-opened runners of turbines to meet the demand. Those runners feature highly efficient performance and less expensive manufacturing costs produced by cutting, not by casting. For the sake of developing further improved unshrouded runners, it is necessary to understand their loss mechanism in detail. Therefore, in this study, the internal flow and the loss mechanism are investigated experimentally and computationally, with two different specific speed hydro turbine runners. First, Euler’s theoretical head on each runner is discussed to identify if they are influenced by the distinct specific speed. It demonstrated that the low specific speed turbine consumes greater potential energy in centrifugal force. Secondary, the loss mechanism in the unshrouded runners is investigated. The result showed that the dominant loss is caused by a tip leakage vortex developed by the collision of a leakage flow at the tip clearance and a secondary flow.
Measurement of dynamic stress and optimized start-up method for prototype Francis turbine
Authors: Mukai T , Shima R , Nakazono M , Tezuka K 
Published: May 2022

Abstract
This paper describes the measurement method and results of dynamic stress for a prototype high head Francis turbine runner, blades of which had fatigue cracks near the root of the blade outlet band side within one-year operation. In order to specify the cause of the cracks, first of all, dynamic stress of the runner blade was measured throughout complete one cycle operation including start-up, no load operation, increase/decrease of load and stopping. Excessive variable strain at the portion near the crack occurred at very low rotational speed during start-up. The large strains occurring during start-up are not due to Rotor-Stator Interaction, other definite cyclic forced vibration or resonance, but the stochastic vibration. Consequently, start-up mode survey was conducted with dynamic stress measurement. As a conclusion, maintaining a small guide vane opening below a certain rotational speed is an effective indicator to reduce the strain during start-up and to minimize the damage caused by this phenomenon.
GLSTM-DTA: Application of Prediction Improvement Model Based on GNN and LSTM
Authors: Liang Yigao , Jiang Shaohua , Gao Min , Jia Fengjiao , Wu Zaoyang , Lyu Zhijian 
Published: May 2022

Abstract
Most prediction models of drug-target binding affinity (DTA) treated drugs and targets as sequences, and feature extraction networks could not sufficiently extract features. Inspired by DeepDTA and GraphDTA, we proposed an improved model named GLSTM-DTA for DTA prediction, which combined Graph Neural Network (GNN) and Long Short-Term Memory Network (LSTM). The feature extraction block consists of two parts: GNN block and LSTM block, which extract drug features and protein features respectively. The novelty of our work is using LSTM, instead of Convolutional neural network (CNN) to extract protein sequence features, which is facilitating to capture long-term dependencies in sequence. In addition, we also converted drugs into graph structures and use GNN for feature extraction. The improved model performs better than DeepDTA and GraphDTA. The comprehensive results prove the advantages of our model in accurately predicting the binding affinity of drug-targets.
Development and Validation of AEBS Anti-slip Control Model for In-wheel Motor Drive EV in AMESim Co-simulation with Matlab/Simulink
Authors: Yang Yu , Liu Yang , Wang Chao 
Published: May 2022

Abstract
The Advanced Emergency Braking System (AEBS) is an intelligent vehicle active safety system to avoid certain sorts of collisions. Recent researches on AEBS emphasized radar, lasers and video camera technologies mostly, also controller developments were studied from Vehicle to Vehicle (V2V) to Vehicle to Pedestrian(V2P) and other aspects with different scenarios, aiming to enhance the active safety of the vehicle. However, most of the current systems focus little on braking performance of AEBS, especially for EV with distributed drive system, like in-wheel motors. In this paper, A 15 Degree of Freedom (DOF) distributed drive Electric Vehicle (EV) model was created and an Anti-slip Controller of AEBS based on the logic threshold method was built. To validate this control strategy, a co-simulation platform between Simulink and AMESim was established and vehicle braking dynamic of four in-wheel motor drive EV was evaluated. Results display that the designed controller not only enhanced the braking performance of AEBS under sudden braking on slippery surface condition, but also meet the requirement of UNECE braking regulation which has practical meanings in boosting active safety of a four in-wheel motor drive EV and development of industrialization.
Simulation and Optimization Design for Energy Absorption Characteristics of Multi-cell Thin-walled Structures
Authors: Ou Disheng , Yao Jiaxiang 
Published: May 2022

Abstract
Based on muti-cell thin-walled structures, construct variety of circular, octagonal, hexagonal multi-cell thin-walled tubes, energy absorption characteristics were studied. Used ANSYS to 12 different cross-sectional shapes of thin-walled tubes axial compression characteristics to nonlinear numerical simulation. The best cross-sectional shape was determined by comparing the energy absorption of different cross-sectional shapes. The thickness of inner and outer walls of thin-walled tubes and stiffened ribs were taken as design variables. Taking the strain energy density and peak force as targets, a response surface model was fitted and multi-objective optimization was performed. The optimization results show that strain energy density and compression efficiency are improved under premise of small peak force.
Simulation and Calculation of Sea State Bias Based on the Electromagnetic Backscattering from the Simulated Nonlinear Rough Sea Surface
Authors: Tian Jiasheng , Shi Jian 
Published: May 2022

Abstract
Due to the improvement of satellite orbit determination technology, sea state bias(SSB) has become the main source of altimeter height measurement error. In this paper, the physical mechanism and causes of SSB are simulated and analyzed by electromagnetic scattering, and the SSB correction method and model are given. Firstly, this paper simulates and studies four kinds of nonlinear rough sea surface and their electromagnetic scattering characteristics for the first time, calculates SSB from the physical mechanism of SSB, and analyzes the physical mechanism and process causes of SSB from the electromagnetic scattering characteristics. Secondly, a fitting model to correct SSB is proposed in terms of the electromagnetic simulation. Finally, the paper compares the “true value of SSB” of HY-2B satellite radar altimeter in China’s offshore waters with SSB calculated by the simulating model. The comparison results show that they are consistent with a weak bias, indicating that it is an effective method to correct SSB by simulating nonlinear rough sea surface and its electromagnetic scattering. It is expected to improve the accuracy of SSB correction by the new way of simulating the physical mechanism and causes of SSB.
A Novel Downlink Transmission Scheme for NOMA Systems
Authors: Sheng B 
Published: May 2022

Abstract
Non-orthogonal multiple access (NOMA) technique can considerably increase the spectral efficiency by serving multiple users simultaneously at the same time-frequency resource, but with different transmit powers. However, superimposing multiple users’ data symbols on the same time-frequency resources will inevitably increase amplitude fluctuation of the composite signal which makes its instantaneous power vary largely at transmitter. To prevent the case of low power appearing, a novel downlink transmission scheme is put forward in this paper. Instead of the original data sequence, its cyclically shifted version with the highest power is transmitted. Since the received signal always has a high signal-to-noise ratio (SNR), up to 3dB gain in bit error rate (BER) performance can be achieved which validates the effectiveness of the cyclically shifting method.
Optimized Design and Implementation of Testing Laboratory Based on Blockchain Technology
Authors: Yuan Jiamei , Ding Jianshun , Ma Yifeng , Zhou Yonggang , Liu Yongge , Chen Yue 
Published: May 2022

Abstract
Traditional testing laboratories suffer from inefficient management of testing equipment, high maintenance efficiency costs, non-transparent testing processes and easy tampering of testing data. This paper makes use of blockchain technology somewhat to optimise the design of data traceability for testing laboratories. Through the optimised design of this paper, an intelligent testing process is achieved for the traditional testing laboratory. At the same time, the level of secure storage of data is improved, making the testing process and test results safer and more reliable. This paper uses blockchain technology to optimise the testing laboratory and achieves significant results. The novel way of using blockchain technology to do data traceability explored in this paper has reference significance and application value for the optimisation and upgrading of traditional laboratories.
A Two-stage Inexact Programming with Value-at-risk under Uncertainty
Authors: Kong Xiangming , Wang Donglin , Zhao Jing , Cheng Rong 
Published: May 2022

Abstract
Measuring risks for two-stage programming model has certain theoretical and actual significance. Therefore, a model of two-stage inexact programming with value-at-risk (TIPV) has been developed. The highlights of TIPV are (1) it can reflect the effects of uncertain parameters including random variables and intervals of fuzzy boundary; and (2) the potential risks of recourse can be revealed. A solution algorithm is developed through considering uncertainties, two-stage and VaR comprehensively.
A Method of Constructing Power System Dispatcher Personas Based on Convolutional Neural Network
Authors: Shi Hujun , Zhang Yunju 
Published: May 2022

Abstract
The recommendation algorithm has been applied in many fields and achieved pretty results in recent years. The personas for a large number of dispatchers in the power system are an indispensable step in the process of intelligent recommendation. In order to recommend dispatchers of different levels according to different operation scenarios, the aim of dispatcher personas is the classification of business level. In this paper, we focused on constructing dispatcher personas of Chinese power system. Unlike of the previous research work, we used convolutional neural network(CNN) to create dispatcher personas. The contributions of this paper are reflected in the following aspects: 1. dataset were built automatically based on internal data; 2. a CNN text classifier were trained to construct the dispatcher personas; 3. the effectiveness of the model is proved by experiments on real data. The experimental results show that the method proposed in the paper is superior to the baseline method and the average accuracy is 96%.
An Improved Schema of Brain-computer Interface Based on Motor Imagery with Eye Movement
Authors: Yu Hao , Deng Yifei , Yan Fuwu , Guan Zhizhou , Peng Fuming 
Published: May 2022

Abstract
Motor imagery (MI) can induce electroencephalogram (EEG) and realize human-computer interaction, but this kind of interaction has poor robustness and low stability. To solve these problems, we improved MI paradigms with eye movement and proposed convolutional neural network classification models based on attention mechanism. We conducted a comparative study to evaluate the performance of MI with different eye movement patterns, i.e. smooth pursuit MI (PMI), saccade MI (SMI) and pure MI. The differences between Squeeze-Excitation (SE) module and Convolutional Block Attention Module (CBAM) module were also explored. The results of power spectral density (PSD) showed that PMI paradigm induced the most significant event-related desynchronization (ERD) phenomenon and the average classification accuracy for PMI signals was also the best in the three paradigms. The combined EEGNet and SE framework achieved an average classification accuracy of 90.77%, which performed better than the model without attention module. PMI can optimize attention allocation of subjects, assist in the construction of motion thinking, and improve the quality of MI signals. EEGNet with SE module showed improved classification performance.