bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overload Response Analysis of UAV in Severe Weather
Authors: Zhu Ting , Xia Shenglin , He Shiwei , Huang Kunshan 
Published: June 2022

Abstract
Turbulence will occur when the aircraft passes through the gust area, which will affect the handling quality and ride quality of the aircraft, increase the bending moment of the wing root and shorten the fatigue life of the structure. At present, in engineering calculation, when the gust load of UAV is considering, the UAV is usually regarded as a rigid body according to the general specification, and the overload response is obtained by solving the dynamic equations of rigid body. The flexibility of UAV is not considered, and the more realistic harsh wind field environment is not considered, so there is a certain deviation between the results and the actual values. Therefore, the gust load was studied considering the aircraft elasticity and the more realistic harsh wind field environment, and compares the calculation results with that considering the standard wind field, and makes a full assessment of the gust overload of UAV. It provides the basis for the design of aircraft structure strength and flight safety, and has important engineering significance.
Study on effect of boundary conditions on simulation of wind flow in mountainous area
Authors: Yin Yuan , Li Yangsen , Lin Ruizong , Liu Zhiwei , Fu Benzhao , Huang Guo , Zhang Hongjie 
Published: June 2022

Abstract
The simulation analysis of wind flow in mountainous area can assist the design of the transmission line. The conventional square computational domain is not conducive for the condition of different wind directions. In this paper, a circular computational domain is proposed for the solution of wind flow in mountainous area in the condition of different wind directions. A square computational domain and a circular one are used to solve the wind flow around the standard hill model. The simulation accuracy of the circular computational domain is verified by the wind profiles at the windward slope, the top of the slope and the leeward slope.
Numerical simulation of sound scattering by a convected vortex
Authors: Ma Ruixuan , Wu Conghai , Han Shuaibin , Zhang Shuhai 
Published: June 2022

Abstract
The sound scattering by a convected isentropic vortex is numerically studied by solving the linearized Euler equations (LEE) with high-fidelity finite-difference methods and non-reflecting boundary conditions. Our computations are in good agreement with previous studies. Simulations for the scattering from a Taylor vortex at a range of convected velocity reveal that the convection of the vortex leads to the spectral broadening of the incident waves. The power spectral density analyses of the scattered pressure in the frequency domain show that the range of the spectral broadening is strongly influenced by convected velocity. This fact can be explained by the relative motion between the vortex and observer associated with the Doppler factor. The sidebands originating from the scattered fields at a fixed point in the frequency domain can be associated with the scattered beams observed in the case of scattering by a steady vortex.
CFD analysis of flow field and hydrodynamic compensation of poppet valve
Authors: Li Ruichuan , Liu Jilu , Ding Xinkai , Cheng Yi , Liu Qi 
Published: June 2022

AbstractThe steady-state hydrodynamic force of cartridge valve poppet valve core reduces the stability of cartridge valve. A circular arc structure is added to the main valve core of the poppet valve to compensate the steady-state flow force. Referring to the structure and parameters of the actual cartridge poppet valve, the three-dimensional geometric model of the flow channel in the valve is established with UG software. CFD method is used to calculate and analyze the flow state of fluid in the poppet valve under the working state of the valve core, and the influence of the arc size and position of the valve core on the steady-state hydrodynamic compensation of the main valve core is studied. The results show that the circular arc structure can realize the hydrodynamic compensation of the valve core and increase the stability of the valve core. When the opening amount is small, properly increasing the height h of the circular arc structure can increase the static hydrodynamic compensation of the valve core; Keep the circular arc structure size L less than 1mm, and the static hydrodynamic compensation effect of the valve core is better.
Lattice Boltzmann simulations of gas bubble transport in proton exchange membrane water electrolysis cells
Authors: Li Gang 
Published: June 2022

Abstract
Gas/liquid two-phase transport is the key fundamental scientific issue in the proton exchange membrane (PEM) water electrolysis cell, which has important effects on the overall performance of water electrolysis and microstructure optimization. In this study, a combination of the lattice Boltzmann two-phase model and the QSGS numerical method was used to numerically model the porous diffusion layer and the micro-channel structure, and investigate the effects of porosity and wettability properties on the gas/liquid two-phase transport process. Simulation results show that the value of porosity will obviously affect the association and distribution pattern of solid particles inside the porous diffusion layer, and the reduction of porosity will cause the association part of solid particles to be narrower and longer, resulting in complex and variable pore channels. Some closed pore channels will appear inside the diffusion layer, which is not conducive to the smooth transmission of gas bubbles. In addition, the increase of contact angle will enhance the interaction force between the bubble and the solid wall, making it difficult for the bubble to fall off from the solid surface. Moreover, the increased interaction force will slow down the sliding speed of gas bubbles, which will result in the fusion of more gas bubbles and increase the risk of blocking the flow micro-channel. This study has initially grasped the mechanisms of micro/meso scale gas bubble transport in the PEM water electrolysis cell, which will provide theoretical basis for the optimized development of high-performance water electrolysis system for hydrogen production.
Study on Rebounding Height of Capsule-shaped Object Based on Serial Coefficient of Restitution
Authors: Pang Bowen , Wang Xinkai , Shuo Liu , Guo Junxi , Hao Guancheng , Pan Wang , Ju Liping 
Published: June 2022

Abstract
The capsule-shaped object, when vertically released at certain initial angular velocity, can easily rebound to exceed the release height. The high-speed camera is used to record experimental images. The software, Tracker, is used to track experimental data. Finally, serial coefficient of restitution and spin parameter can be statistically summarized. MATLAB is used to process images to obtain the correlation between relevant data of the capsule rebounding status and serial coefficient of restitution, and bases for spin direction changes before and after rebounding of the capsule. ANSYS is employed to obtain simulation data. At last, evidence is provided to substantiate that the serial coefficient of restitution can, under some conditions, allow the capsule-shaped object can rebound higher than the release height, and that the spin direction and status of the capsule-shaped object can be identified by the value of spin parameter.
The water impact load study for seaplane during get-off and alighting process on rough water
Authors: Huang Miao , Wu Bin , Li Chenghua 
Published: June 2022

Abstract
The scaled model tank test on rough water of a seaplane is conducted, and then we study the influence rules of wave length, wave height and test velocity on water load systematically, the results turn out to the that: the water load decreases as the wave length goes up, it decreases rapidly when the model moves at relatively high speed and slowly when model moves at low speed. as the test velocity goes up, the water load increases much more rapidly at short wave length than that at long wave length. when the model remains navigation status, the water load change slightly but rapidly in a linear fashion as to wave height when model remains planning status. in conclusion, the water load gets relatively high value at the status of higher speed and shorter wave length, and relatively low value at the status of lower speed and longer wave length.
Formation of accretion disk by hydrodynamic subcritical transition
Authors: He Ziting 
Published: June 2022

Abstract
This work employs input-output analysis that is computationally efficient to provide insight into the dominant length scale the transition mechanism in rotating plane Couette flow that is relevant to the accretion disk. We also incorporate componentwise analysis to isolate the effect of different input body forces and different output velocity responses. We compared results associated with three different Reynolds numbers and rotation numbers considering both the overall effect and the effect under isolated input and output directions. We observe different patterns in which the maximum energy amplification strength changes as Reynolds number and rotation number change. We also derive the scaling law of the largest input-output gain over Reynolds number and rotation number, which suggests a higher rotation rate is playing a stabilizing role. We observe that the maximum amplification at rotation number equal to one shows symmetry against the lift-up mechanism in non-rotating plane Couette flow. As the stabilizing effect of rotation is further increased, we observe the most amplified flow structures are more elongated in the spanwise direction reminiscent of the Taylor-Proudman effect.
Design of Gas Drainage Monitoring System Based on Siemens S7-1500 PLC and WinCC
Authors: Wang ZuXun 
Published: June 2022

Abstract
In order to ensure the reliable and stable operation of the gas drainage system and ensure the safe production of coal mines, a gas drainage monitoring system is designed. The monitoring system adopts Siemens S7-1500 series PLC as the core control unit. By configuring function modules and cooperating with WinCC configuration software to carry out the program design of the upper computer, the one-key control and automatic regulating of the gas drainage system is realized. The monitoring system adopts smart sensors, and improves the anti-interference ability of the system through digital signal transmission, adopts PID and cascade PID advanced control strategies to control the flow and pressure, and improves the regulating accuracy of the drainage system, adopts the limit threshold method and data mutation method combined with early warning reduces the unplanned shutdown of the drainage pump and improves the working efficiency of the drainage pump.
Human joints estimation system of rescue robot with occlusion
Authors: Fang Zhenghui , Wang Anna , Bu Chunguang , Sui Jin , Fan Xiaoliang 
Published: June 2022

Abstract
The human body is often in a partially visible state during rescue at the disaster site. At the same time, when the human body is grasped, the camera located on the actuator at the end of the robotic arm cannot fully bring the human body into the field of view. The existing human pose estimation algorithms do not perform well in this situation, and a joint detection method that can estimate the complete human pose through partial human body information and can perform data refresh in real time is required. We use the occlusion part classification module to extract the weight vector, re-weight it and the joint features extracted from AlphaPose, and add human body geometric constraints when generating 3D human body joints to obtain more accurate 3D human body joint positions. Finally, the robot is successfully used to complete the human grasping experiment, which verifies the effectiveness of the algorithm.
Motion Planning of Unmanned Aerial Vehicle Based on Rapid-exploration Random Tree Algorithm
Authors: Cai Fake , Liu Danyang , Yuan Weihan , Ding Shuo , Ning Yongxu , Yue Chenyang 
Published: June 2022

Abstract
In the study of route planning problems in complex environments, in order to reduce the flight cost of unmanned aerial vehicles (UAVs), it is necessary to achieve a better balance between planning time and path quality. This paper utilizes the Rapid-exploration Random Tree (RRT) algorithm for motion planning of a fixed-wing UAV and a multi-rotor UAV (i.e., a quad-rotor UAV), and gives the origin and destination locations on a 3-D map. By following aerodynamic constraints such as maximum roll angle, flight path angle, and airspeed, a collision-free and flight-friendly path is found through simulation. In addition, this paper employs a path smoothing algorithm to simplify the 3-D Dubins path and generates the shortest trajectory. The simulation results show that the RRT and the optimization method have faster convergence speed and shorter search time, reduce redundant planning points, shorten the planning track, and improve the track planning efficiency.
Direct detection of charged particles with SiPMs
Authors: Carnesecchi F. , Vignola G. , Agrawal N. , Alici A. , Antonioli P. , Arcelli S. , Bellini F. , Cavazza D. , Cifarelli L. , Colocci M. , Durando S. , Ercolessi F. , Garbini M. , Giacalone M. , Hatzifotiadou D. , Jacazio N. , Margotti A. , Malfattore G. , Nania R. , Noferini F. , Pinazza O. , Preghenella R. , Ricci R. , Rignanese L. , Rubini N. , Scapparone E. , Scioli G. , Strazzi S. , Tripathy S. , Zichichi A. 
Published: June 2022

Abstract
The direct response of Silicon PhotoMultipliers being
traversed by a MIP charged particle have been studied in a
systematic way for the first time. Using beam test data, time
resolution and the crosstalk probability have been measured. A
characterization of the SiPM by means of a laser beam is also
reported. The results obtained for different sensors indicate a
measured time resolution around 40–70 ps. Although particles are
expected to traverse only one SPAD per event, crosstalk measurements
on different sensors indicate an unexpected higher value with
respect to the one related to the sensor noise.
Predicting nitrate leaching loss in temperate rainfed cereal crops: relative importance of management and environmental drivers
Authors: Tamagno Santiago , Eagle Alison J , McLellan Eileen L , van Kessel Chris , Linquist Bruce A , Ladha Jagdish Kumar , Lundy Mark E , Pittelkow Cameron M 
Published: June 2022

Abstract
Nitrate (NO3) leaching from agriculture represents the primary source of groundwater contamination and freshwater ecosystem degradation. At the field level, NO3 leaching is highly variable due to interactions among soil, weather and crop management factors, but the relative effects of these drivers have not been quantified on a global scale. Using a global database of 82 field studies in temperate rainfed cereal crops with 961 observations, our objectives were to (a) quantify the relative importance of environmental and management variables to identify key leverage points for NO3 mitigation and (b) determine associated changes in crop productivity and potential tradeoffs for high and low NO3 loss scenarios. Machine learning algorithms (XGboost) and feature importance analysis showed that the amount and intensity of rainfall explained the most variability in NO3 leaching (up to 24 kg N ha−1), followed by nitrogen (N) fertilizer rate and crop N removal. In contrast, other soil and management variables such as soil texture, crop type, tillage and N source, timing and placement had less importance. To reduce N losses from global agriculture under changing weather and climatic conditions, these results highlight the need for better targeting and increased adoption of science-based, locally adapted management practices for improving N use efficiency. Future policy discussions should support this transition through different instruments while also promoting more advanced weather prediction analytics, especially in areas susceptible to extreme climatic variation.
The influence of local waste management culture on individual recycling behavior
Authors: Kountouris Yiannis 
Published: June 2022

Abstract
The transition towards sustainable consumption and production requires public engagement and support. In this context, understanding the determinants of individual pro-environmental behavior can assist in sustainability policy design, and contribute to explaining cross-country and regional differences in its implementation and effectiveness. This paper examines the influence of local waste management culture on individual recycling behavior. To isolate the impact of location-specific norms, habits and traditions comprising waste management culture from the confounding effect of contemporaneous local economic and social conditions, we use data from over 40 000 domestic immigrants in Greece. Estimating models relating individual recycling activity in the region of current residence to recycling practices in the region of origin, we find robust evidence that region of origin waste management practices have quantitatively and statistically significant influence on individual recycling behavior: a 10 percentage point increase in the prevalence of recycling in the region of origin, increases the probability a subject recycles by 0.9 percentage points. The results suggest that locally prevailing waste management norms and practices influence individual recycling behavior independently of local economic, social and environmental circumstances. Designing effective sustainability policy may need to account for regional variation in norms and preferences, and encourage investment in the development of sustainable waste management culture.
Stretched lignin/polyacrylonitrile blended carbon nanofiber as high conductive electrode in electric double layer capacitor
Authors: Kumar Manish , Taira Shogo , Pakkang Nutthira , Shigetomi Kengo , Uraki Yasumitsu 
Published: June 2022

Abstract
In this study, lignin-based conducting carbon nanofiber mat was prepared by electrospinning followed by a thermal treatment. Lignin is a sustainable carbon precursor. Polyacrylonitrile (PAN) acts as a binder polymer, which increases the viscosity of the lignin solution using dimethylformamide solvent and helps in the formation of a stable nanofiber. The mixture solution was electrospun, followed by stabilisation and carbonisation to yield carbon nanofibers (CNFs). A fixed amount of external load was provided to the lignin fiber mat during the stabilisation procedure and then carbonised to yield stretched carbon nanofibers (S-CNFs). On stretching the mat, surface conductivity was enhanced by 3 times, and the surface area by 1.3 times compared to that of non-stretched CNFs. Finally, the electric double layer capacitor (EDLC) was assembled with the resulting (CNFs and S-CNFs) nanofiber mat using 6 M of KOH aqueous solution. S-CNFs mat exhibits a specific capacitance of 266 F g−1, which was higher than that of CNFs, i.e. 258 F g−1 at a scan rate of 5 mVs−1 .
Enhanced relaxor behavior and high energy storage efficiency in niobium substituted (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 ceramics
Authors: P Vineetha , Jose Roshan , Vijay Ammu , S Charan Prasanth , K Venkata Saravanan 
Published: June 2022

Abstract
The microstructure, dielectric properties, relaxor behavior, and energy storage efficiency of un-substituted and niobium (Nb) substituted (Ba0.85 Ca0.15)(Zr0.1 Ti0.9) 1-x NbxO3 (for x = 0, 0.02 and 0.05) samples prepared by the solid-state reaction method has been studied in detail. All the samples exhibited perovskite structure with no trace of impurity. Composition-dependent phase transition was also observed on the addition of Niobium. At room temperature, the co-existence of rhombohedral and tetragonal phases is observed in the unsubstituted samples. As the composition changes from x = 0.02 to x = 0.05, a structural change from tetragonal to cubic is observed. A remarkable reduction in grain size, from 90 μm (for x = 0) to 1.21 μm for (x = 0.05), is observed with the addition of Niobium. This result suggests that Niobium acts as a grain growth inhibiter in barium calcium zirconium titanate (BCZT) ceramics. The effect of Niobium on transition temperature is studied from the temperature-dependent dielectric permittivity graph. It was clear that the transition temperature shifted to a lower temperature region, and for x = 0.05, at a very low temperature (−23 °C/250 K) the tetragonal to cubic transition was observed. At x = 0.05, the temperature-dependent dielectric permittivity showed a broadened curve, indicating a diffuse phase transition. The diffuse phase transition in Nb substituted samples is explained by Uchino and Nomura modified Curie Weiss law.
Moreover, the observations on temperature-dependent dielectric permittivity measurements at various frequencies suggest that the substitution of Nb5+ induces relaxor behavior. The energy storage efficiency of unsubstituted and Nb substituted samples was calculated from the polarization versus electric field graph. A high storage efficiency of 84% was obtained for the Nb substituted sample (x = 0.05) at 12 kV cm−1. Enhanced relaxor behavior and increased storage efficiency were observed in (Ba0.85 Ca0.15)(Zr0.1 Ti0.9) 1-x NbxO3 at x = 0.05. Thus we suggest that these are promising materials for energy storage applications.
Improved sensitivity on detection of Cu and Cr in liquids using glow discharge technology assisted with LIBS
Authors: SUN Duixiong , WANG Yarui , SU Maogen , HAN Weiwei , DONG Chenzhong 
Published: June 2022

Abstract
Laser-induced breakdown spectroscopy-assisted glow discharge (LIBS-GD) for analysis of elements in liquid was proposed, and it was applied to detect heavy metals in highly sensitive mixed solutions of Cu and Cr. During the experiments of GD and LIBS-GD, the experimental parameters have been optimized and the optimal voltage is 450 V, laser energy is 60 mJ, and the delay time is 4000 ns. Furthermore, the calibration curves of Cu and Cr under GD and LIBS-GD experiments have been established, and the limits of detection (LODs) of Cu and Cr were obtained with the method of GD and LIBS-GD, respectively. The LOD of Cu decreased from 3.37 (GD) to 0.16 mg l−1 (LIBS-GD), and Cr decreased from 3.15 to 0.34 mg l−1. The results prove that the capability of elemental detection under LIBS-GD has improved compared with the GD method. Therefore, LIBS-GD is expected to be developed into a highly sensitive method for sewage detection.