bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lyman-α polarization from cosmological ionization fronts. Part I. Radiative transfer simulations
Authors: Yang Yuanyuan , Koivu Emily , Zeng Chenxiao , Long Heyang , Hirata Christopher M. 
Published: May 2023

Abstract
In this paper, we present the formalism of simulating Lyman-α emission and polarization around reionization (z = 8) from a plane-parallel ionization front. We accomplish this by using a Monte Carlo method to simulate the production of a Lyman-α photon, its propagation through an ionization front, and the eventual escape of this photon. This paper focuses on the relation of the input parameters of ionization front speed U, blackbody temperature T
bb, and neutral hydrogen density n
HI, on intensity I and polarized intensity P as seen by a distant observer. The resulting values of intensity range from 3.18 × 10-14 erg/cm2/s/sr to 1.96 × 10-9 erg/cm2/s/sr , and the polarized intensity ranges from 5.73 × 10-17 erg/cm2/s/sr to 5.31 × 10-12 erg/cm2/s/sr. We found that higher T
bb, higher U, and higher n
HI contribute to higher intensity, as well as polarized intensity, though the strongest dependence was on the hydrogen density. The dependence of viewing angle of the front is also explored. We present tests to support the validity model, which makes the model suitable for further use in a following paper where we will calculate the intensity and polarized intensity power spectrum on a full reionization simulation.
Thermal buckling behavior of metal/composite wall panels
Authors: Deng Wen-liang , Wang Bin-Wen , Lei Kai , Wu Jing-Tao 
Published: May 2023

Abstract
This paper has carried out the research on the thermal buckling behavior of the metal/composite composite structure wall panel. The thermal buckling behavior of the hybrid structure has been studied from analytical methods, finite element methods and experimental tests. Aiming at the thermal buckling behavior of the hybrid structure from room temperature 20°C to -55°C, non-contact optical testing technology is used to obtain the thermal buckling deformation parameters of the entire temperature history, and the critical heat of the hybrid structure is obtained through theoretical solution, simulation and data judgment methods. The buckling temperature reveals the thermal buckling deformation law of the mixed structure wall panel under the aircraft temperature envelope. Conclusion: The change of structural off-plane displacement is the manifestation of structural buckling instability.Although buckling instability occurs in the wall structure during the cooling process, the structure can still be restored to a normal state without post-buckling. The slope of structural deformation changes dramatically after -15°C, basically showing a linear relationship; the theoretical solution, simulation method and data judgment method determine the critical temperature of structural thermal buckling with a maximum difference of 4.8°C. The test data judgment method can be used for thermal buckling Determination of critical load.
Three-dimensional numerical study on the interaction between RDC and NGV
Authors: Xue Sainan , Yang Bo , Liu Denghang , Xia Zhenjuan , Ma Hu 
Published: May 2023

Abstract
In this paper, the three-dimensional numerical method is used to study the change of the internal flow field distribution characteristics of a RDC with a deflector installed at the outlet, using the premixed gas of kerosene and air as reactants. It is found that the total pressure in the front section of the combustor has been improved. Different configurations of deflectors were designed. It was found that the flow field in the combustion chamber could not be significantly changed by changing the number of blades, but the maximum average total pressure and the total pressure loss in the mixing section could be effectively improved by adjusting the angle of incidence. Because the propagation direction of rotating detonation wave and the deflector blade have directionality, the study found that when the two directions are opposite, the reflected shock wave formed at the inlet of the deflector changes greatly, the working environment of the fixed blade is worse, the uniformity of gas after passing the deflector decreases, the flow field along the axial average total pressure loss increases significantly, and the peak value of the total pressure shifts significantly downstream. The study of the interaction between NGV and RDC provides a basis for the design of the rotaing detonation turbine engine.
Parameter modelling of fleet gas turbine engines using gated recurrent neural networks
Authors: Shuai M , Yafeng W , Hua Z , Linfeng G 
Published: May 2023

Abstract
Oriented by the gas-path fault diagnosis of aircraft engines, this work presents a novel parameter modelling scheme for fleet gas turbine engines based on gated recurrent neural networks. Four dynamic models are constructed based on the long short-term memory (LSTM) network and gated recurrent unit (GRU) network to predict the total temperature at the high-pressure turbine outlet of gas turbine engines. We apply the dynamic networks to model the engine parameters by solving a sequence-to-feature regression problem. The proposed scheme is assessed through a comprehensive comparison study on training performance, validation performance, generalization, robustness against noise, and extrapolation performance. The results showed that the proposed network models performed a promising performance on parameter modelling. For the proposed four network models, the NARX-based models have better one-step-ahead prediction performance, while the state-space-based models have better long-term prediction performance. The discussion of the results also showed that the GRU network was an effective data-driven model for parameter modelling of gas turbine engines.
Numerical study of nozzle erosion in a hybrid rocket motor with wagon wheel fuel grain
Authors: Jiang Xianzhu , Tian Hui , Diao Chengyong , Yu Ruipeng , Zhao Sheng , Zhu Hao 
Published: May 2023

Abstract
Nozzle erosion directly affects the design quality of hybrid rocket motors, and it is a critical issue that restricts the practical application of hybrid rocket motors. In this paper, coupled numerical simulations of combustion flow field and thermochemical erosion of a graphite nozzle in a hybrid rocket motor with multi-port wagon wheel fuel grain are carried out. The results indicate that distributions of temperature, species and erosion rate in the flow field of hybrid rocket motor with wagon wheel grain show symmetrical characteristics related to the grain shape. The erosion rate decreases at first and then increases at the convergent section of throat insert, and it reaches the maximum value at the transition arc between convergent section and straight section of the throat. The maximum erosion rates at the central hole (position A) and outer edge of wheel holes (position B) are 0.0625 mm/s and 0.0902 mm/s, respectively. The erosion rate increases slowly in the straight section of the throat and it decreases gradually in the divergent section. Circumferentially inhomogeneous ablation occurs in the throat, and the erosion rate at the front end of throat straight section varies from 0.0484 mm/s to 0.0809 mm/s. The main oxidizing species causing thermochemical erosion are H2O and OH. At position A in the front end of throat straight section, erosion rates caused by H2O and OH are 66.50% and 30.48%, respectively. With the increase of oxidizer mass flow rate, the combustion chamber pressure increases linearly, and the erosion rate at position A in the front end of throat straight section gradually increases, but the growth rate decreases.
An advanced warning model of airplane hard landing based on Adaboost
Authors: Zhang R , Cai L Y T , Huang D J , Gao C Y 
Published: May 2023

Abstract
This paper breaks through the limitation of establishing early warning logic in the time dimension of the previous hard landing early warning model. In this research, flight altitude has been set as the scale of the corresponding early warning logic. According to the specific characteristics of the original flight parameter data set, the data preprocessing methods have been studied. The application of oversampling and frequency compression methods effectively solved the problems of different sample size and multi-frequency flight parameters in the original data set. On this basis, the method of ensemble learning is used to establish the early warning model of aircraft hard landing based on Adaboost. Further, the model is optimized to ensure the accuracy and generalization ability of the early warning model. Verified by the case study of the actual flight parameter data of Airbus A320 aircraft, the early warning model can realize high-precision prediction of hard landing events, which is of great significance for the improvement of the landing safety level of the aircraft in constructing both.
Double three-phase permanent magnetic motor based on the smallest copper consumption and maximum torque single phase lack of phase compromise and tolerance error control
Authors: Song Bing , Cui Yebing , Zhang Xinbin , Fang Cheng , Wang Kai 
Published: May 2023

Abstract
In multiphase motors, the consumption of stator copper and the output of torque are a pair of constraints affecting motor control performance. According to the constraint relationship between the them, this paper proposes a method to balance the consumption of copper and the output of torque by using the weight coefficient. Through this method, the efficient control of fault-tolerant motors can be realized, and the balance of output torque and efficiency can be realized. Finally, the accuracy of the control strategy is verified by the motor loading platform.
Influence of cavitation state and launch angle on water-exit process of vehicle based on moving domain method
Authors: Li Jiamin , Zheng Jian , Jing Shibo 
Published: May 2023

Abstract
This paper, aiming at the water-exit process of the vehicle with cavitation, based on the moving domain method coupled with the SDOF (six degrees of freedom) solver, using VOF (volume of fluid) multiphase model and the Schnerr-Sauer cavitation model, carrying out numerical simulation research on multi-conditions. Comparing vertical launch vehicles with different water-exit Ca (cavitation number) cases, the sudden decrease in cavitation number is closely related to the cavitation state, and there is a maximum influent cavitation state of the cavitation collapse on the process of the water-exit. Comparing different initial launch angle cases, it is found that there is a most unstable launch angle, which makes the angular deflection of the vehicle the most severe during the water-exit process.
Research on the association algorithm of space-target track segments
Authors: Jia Senhao , Sun Shaoyong , Qu Weizhi , Jin He , Li Libin 
Published: May 2023

Abstract
In order to improve the tracking continuity and stability of space targets, the track segments association algorithms are studied. The extrapolation prediction based on the C-W motion model in the main spacecraft orbital coordinates is carried out. The model of space target is used to forecast and extrapolate the trajectory of the interrupted target. Based on the extrapolation of the terminated track, the track segments are associated by using the extrapolation results and the state update values at the first few moments of each track segment after the interruption. In this way, the association and fusion of the orbit of the space target interruption is completed. The results can improve the tracking accuracy of space targets and the trajectory association.
The effect of reflux schemes in hydrogen peroxide electric pump on anti-cavitation of inducer
Authors: Gu Xiaoming , Tian Hui , Wang Jiangning , Lu Yudong , Jiang Xianzhu , Zhu Hao 
Published: May 2023

Abstract
Hydrogen peroxide electric pump supply system can provide an improvement to hybrid rocket motor performance. Due to the physical and chemical properties of hydrogen peroxide, a canned pump scheme is more suitable to be used in hybrid rocket motor. The high-temperature liquid between the rotor and stator of the electric pump, returning to the inlet of the inducer, has a considerable influence on the anti-cavitation performance. The numerical simulation results show that the optimal reflux scheme is different when the inlet pressure range of the inducer is different. When the inlet pressure of the inducer is 0.4 MPa, the performance of the inducer is less affected by the reflux schemes, and the optimal scheme is the axial scheme in the simulation. When the inlet pressure is 0.12 MPa and there is a large cavitation area in the inducer, the radial reflux scheme is better than the axial and mixed reflux. When the inlet pressure is 0.1 MPa and the cavitation areas almost extend to the whole blade passage, the radial reflux scheme is much better than the axial and mixed reflux.
Fault detection and isolation of electromechanical actuator based on SAE-BiLSTM
Authors: Tao Xinxin , Guo Yingqing , Zhao Wanli , Zhou Qifan , Xu Kejie 
Published: May 2023

Abstract
The control technology of electromechanical actuator(EMA) and its fault diagnosis is one of the key problems of multi-electric aircraft study. The method based on deep learning is used to diagnose and isolate the classic faults of EMA. The simulation model of EMA is modeling according to the working principle and control law. Four typical faults of EMA are studied,including return channel jam, spall, motor fault, and position sensor fault. Sparse Auto Encoder (SAE) algorithm can perform adaptive extraction of sensor data, which preserves dimensionality reduction and compression while preserving important features. Bidirectional Long Short Term Memory (BiLSTM) neural network is used to effectively process the time series data, which considering both past and future data during the fault diagnosis process. The established EMA model is simulated to obtain normal and faulty data sets, which are used to train the network by SAE-BiLSTM algorithm, and then the trained network is used for online fault diagnosis. After the experiment, SAE-BiLSTM algorithm can well complete the EMA fault detection and isolation.
Numerical analysis of separation dynamics for space debris removal payload based on solid thruster
Authors: Tao Xiaoyu , Yang Haibo , Deng Hanyu , Zhou Hao 
Published: May 2023

Abstract
Aiming at the current mainstream flying anchor payload for space debris removal, a solid thruster was proposed as the separation driving force, and a complete dynamic model of the spacecraft platform and payload were established. The effects of the gap between the directional button and the directional tube, thrust eccentricity and the initial attitude of the platform on the target accuracy under the flying anchor payload were studied. The analysis results showed that the initial attitude of the platform was the main factor affecting the target accuracy of the flying anchor payload. The control gap between 0.1mm ~ 0.25mm can effectively reduce the displacement of payload separation and the influence of disturbance on the platform.
A SysML-centric integration framework for helicopter fuel system development
Authors: Zhao H , Wu W K , Hu X M , Guo Y Q , Zhang C , Hao G X 
Published: May 2023

Abstract
Data and model exchange between SysML (Systems Modeling Language) Modeling tools and other system development tools is a critical aspect of Model-Based Systems Engineering (MBSE). This paper introduces an application of the SysML-centric integration framework, which allows integrating multi-disciplinary engineering models into a SysML Modeling environment. A design practice of helicopter fuel system is then presented to illustrate how to combine the external simulation models within the SysML Models to explore the performance and verify corresponding requirements. In this case, FMI (Functional Mock-up Interface) based co-simulation creates a bridge between SysML Modeling tools and simulation tools in the SysML-centric integration framework. According to the practice, we believe it will significantly improve model consistency and traceability to provide early evaluation of concepts during conceptual design phase.
Research on transition state control strategy of propfan engine based on SAC algorithm
Authors: Zhou Jiang-tao , Wang Ya-fan , Yang Zhao-xing , Zhao Dong-zhu 
Published: May 2023

Abstract
The engine performance search control plays a key role in the engine operation. How to find a suitable algorithm to make the control process fast and stable without exceeding various engine constraints is very important. With the continuous development of deep reinforcement learning in recent years, not only many deep reinforcement learning algorithms have emerged, but also deep reinforcement learning has made rapid development in the field of control. Considering the strong perception and decision-making ability of the deep reinforcement learning algorithm, and in order to adapt to the strong nonlinearity of the engine model and avoid falling into the local optimal value, this paper uses the SAC (Soft Actor Critical, SAC) algorithm to optimize the transition state performance. By introducing the strategy information entropy into the objective function, the search stability of the algorithm and the final optimization effect are significantly improved. Finally, the SAC algorithm is compared with the DDPG algorithm to optimize the transition state performance, and the results show that the SAC algorithm has a better optimization effect on the transition state performance.
Can data sharing really provide added value? Practical data sharing recommendations for the wind energy sector
Authors: Barber S , Hammer F , Henderson C 
Published: May 2023

Abstract
The digital era offers many opportunities to the wind energy industry and research community and digitalisation is one of the key drivers for reducing project costs and risks. The WeDoWind framework has been developed in order to address one of the main challenges to a successful exploitation of digitalisation in wind energy - data sharing and collaboration. The main innovation of this framework is the way it creates tangible incentives to motivate different types of people to actually share data and knowledge in practice. In this work, we carry out a detailed analysis of the strengths and weaknesses of the WeDoWind framework based on a survey filled out by participants of two use case studies and observations from the WeDoWind development team. The results show that the framework successfully enhances collaboration and data sharing in the sector. The results allowed a set of practical data sharing recommendations for the wind energy sector to be developed, which are being continuously improved based on our experience with the WeDoWind framework. They can be applied by anyone wishing to share data effectively and efficiently.
Offshore wind in the race for ocean space: A forecast to 2050
Authors: Pettersen S S , Aarnes Ø , Arnesen B , Pretlove B , Ervik A K , Rusten M 
Published: May 2023

Abstract
This paper reports on recent results on the race for space in our ocean, based on DNVs forecasting efforts into the Blue Economy. We find that the world will see a large increase in the usage of ocean area by offshore installations for energy and food production, with the European area for installations growing close to five-fold to 2050. If not carefully managed, the energy transition in the ocean risks triggering a race for space and conflicts with other stakeholders. By introducing the Spatial Competition Index (SCI), we propose a new indicator to measure the level of competition among ocean industries and nature. SCI forecasts to 2050 reveal that shallow waters close to shore will face significant increases in pressure from ocean industries. This indicates that there is a need for co-existence to be considered in new offshore wind development projects, and for developers to increasingly consider floating structures.
Effect of curtailment scenarios on the loads and lifetime of offshore wind turbine generator support structures
Authors: Robbelein Koen , Daems P.J. , Verstraeten T. , Noppe N. , Weijtjens W. , Helsen J. , Devriendt C. 
Published: May 2023

Abstract
Curtailment is a known phenomenon for wind turbine operators of both onshore and offshore wind turbine generators (WTG). Curtailment refers to the situation in which the power output of all WTG’s within a windfarm is forced below the expected power output at the occurring environmental conditions. A direct consequence of curtailment is the loss of power production. In the present contribution further consequences of curtailment of an offshore wind farm (OWF) are studied from the perspective of the support structure, in specific the foundation. In relation to curtailment a couple of potentially critical operational conditions impacting the fatigue consumption of the support structure can be identified. Besides the standstill during operational windspeed conditions, in specific damaging for the +7MW generation WTG’s, curtailment introduces repeated transitions between operational conditions. Since transitions between operational conditions of a WTG are known to be a cause of high fatigue loads in the structural components of the WTG, their increased occurrence due to curtailment might also have an impact on the fatigue consumption of the support structure. With the growing interest of the industry to quantify and potentially optimize the structural lifetime consumption in view of potential lifetime extension of OWF assets, any potential fatigue damaging operational condition is to be investigated. The present work focusses on the investigation of the impact these transitional load cycles may have on the structural lifetime of the WTG foundation. To assess the impact on lifetime, the assessment of the damage equivalent loads (DEL) derived from structural health monitoring (SHM) data are used as a data-driven alternative for model-based load simulations. In the present work such data-driven lifetime assessment studies the impact of curtailment regimes with different frequency of stop and start cycles on the structural lifetime. The study is performed based on 1 year of SHM data collected from two OWF’s. The assessment demonstrates that the impact of additional transitional load cycles on the structural fatigue life consumption is to be considered when defining a long-term curtailment strategy for an OWF.