bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conjugate heat transfer in the mode of thermal gravitational-capillary convection in the model of a fuel tank, after a sudden heating of the sidewall
Authors: Mitin K. A. , Berdnikov V. S. , Bodneva N. I. , Ryabov V. O. 
Published: December 2021

Abstract
The evolution of unsteady gravitational-capillary convection in a layer of ethyl alcohol with a free surface after sudden electric heating of one of the vertical walls of a rectangular cavity was investigated numerically. The effect of the incoming flow of hot liquid on the time evolution of the temperature field on the opposite thin metal wall of the cavity was investigated. The calculations were carried out by the finite element method in the conjugate two-dimensional formulation with the Prandtl number Pr = 16, and the range of Grashof numbers determined by the heat flux density, 33·103 ≤ Gr ≤ 28·106. It is shown that the maximum local temperature gradients occur on the wall near the liquid-gas interface.
Dynamics of bubble growth during boiling at microgravity
Authors: Ronshin F , Sielaff A , Tadrist L , Stephan P , Kabov O 
Published: December 2021

Abstract
The purpose of this investigation is to study the mechanisms of boiling heat transfer in microgravity conditions. The RUBI (Reference mUltiscale Boiling Investigation) is an experiment where the basic phenomena of boiling heat transfer processes on a heated surface are investigated on the ISS (International Space Station). The special focus is paid to the coupling of macroscopic bubble dynamics from nucleation, growth and detachment combined with the microscopic phenomena in the thin films and micro layers on the heater, underneath the boiling bubbles. The image treatment program has been developed in order to extract the bubble volume as well as the contact angle from the experimental images. The first data of the bubble growth dynamics have been obtained and analysed.
Spatiotemporal distribution of the temperature field inside the thin heated foil during impacting liquid spray
Authors: Cheverda V V , Gigola T G , Somwanshi P M 
Published: December 2021

Abstract
The spatiotemporal distribution of the temperature inside a constantan foil during impacting spray is resolved experimentally in the present work. The received infrared image sequence will be used to find the local and average heat transfer coefficient of the foil. In the future, the results obtained will be used to calculate the heat flux in the region of the contact line of each drop.
The study of spray impact on the heated sapphire plate
Authors: Gigola T G , Cheverda V V 
Published: December 2021

Abstract
The process of the liquid spray impact on the heated surface is studied experimentally using the IR-transparent sapphire plate method. The spatiotemporal distribution of the temperature field on the sapphire substrate surface during impacting spray is received. The obtained experimental data are an important step in a study of the local characteristics of heat transfer in the areas of the contact lines during liquid spray impact on the heated surface. Further, the local heat fluxes and heat transfer coefficients will be determined by solving the problem of thermal conductivity in the sapphire substrate.
Assessment of the technical condition of lift guides using a magnetic field
Authors: Lonkwic P , Krakowski T , Ruta H 
Published: December 2021

Abstract
The systems that monitor individual components of machines and devices are under constant development. The ability to detect damages at an early stage allows failures to be prevented, so any uncontrolled downtime can be predicted in a controlled manner. Continuous monitoring of technical condition is an activity that also helps to reduce the losses due to equipment failures. However, not all areas can be monitored continuously. Such areas include lift guides where wear and tear can occur naturally, i.e. through abrasion of the material layer due to interaction with moving guide shoes or after emergency braking. Emergency braking causes local damages to the guide through plastic deformation of its surface resulting from indentation of the knurled roller of the brake. Such places are cleaned mechanically, which results in local reduction of the cross-sectional area. In such a case, it is difficult to continuously assess the technical condition of guides due to the prevailing operating conditions. Therefore, a concept of a head enabling assessment of the technical condition of guides at every stage of their operation has been developed. This article presents the novel concept of a magnetic head used for assessing the technical condition of lift guide rails that are the running track of lifting equipment. The initial tests were performed on the original test setup. The concept of the developed measuring head was verified for correct operation on specially prepared flat bars with holes. The results obtained in the form of laboratory tests proved that the proposed measuring head concept can be applied to the measurements under real conditions.
Numerical analysis of undercut anchor effect on rock
Authors: Jonak J , Karpiński R , Wójcik A 
Published: December 2021

Abstract
The paper presents the results of a numerical analysis using the Finite Element Method (FEM) of the friction issue in the contact between the undercut anchor head and rock during anchor pull-out. Formation of failure zone of rock medium was analysed assuming different Coulomb friction coefficients in the contact zone of conical anchor head with a rock. The problem is interesting as regards practical aspects of rock mass loosening during anchor pull-out. The analysis revealed a significant effect of the friction coefficient on the propagation and extent of the failure zone. Increasing the friction factor significantly decreases the extent of the failure zone measured on a free rock surface.
Composite plate analysis made in an unsymmetric configuartion
Authors: Falkowicz K 
Published: December 2021

Abstract
The work presents a thin-walled plate element with the central rectangular cut-out which can be use as an elastic or load-bearing element. Plates were made of carbon epoxy laminate and subjected to uniform compression. Plates were simply supported on shorter edges, and loaded axial load. The study included analysis of the critical and weakly post-critical behavior using experimental and numerical methods. Numerical analysis was performed with using linear analysis of eigenvalue problem to determination critical loads. The second step connected nonlinear analysis of structure with initiated geometrically imperfection corresponding to the flexural-torsional buckling mode of the plate. To the numerical calculations the commercial ABAQUS program was used.
Simulation research of the strength of an engine mount in an aircraft piston diesel engine
Authors: Magryta P , Pietrykowski K 
Published: December 2021

Abstract
The article presents strength simulations of a mount for mounting the test engine. Mounted on a stationary test stand, this mount consists of external fixings, fixings to stabilize the engine and tubular elements as a truss. These tubular elements are pipes made of seamless black steel. The material of the truss is S235JR steel. The article examines three different versions of the mount: mount no. 1 - initial mount, mount no. 2 - mount after a modification of pipe arrangement, mount no. 3 - mount after a modification of pipe wall thickness. For each version of the mount and subsequent calculation steps, the same boundary conditions and results legend were assumed. All calculations were made in Catia v5 in the Generative Structure Analysis module. To reflect the conditions prevailing during the engine operation on the test bench, the following conditions as mount load were adopted: gravity from the engine mass as 1000 N; engine thrust as 5000 N, and engine torque as 227 Nm. First, the model was pre-calculated to check the influence of mesh size on the obtained results. 2 mm parabolic tetrahedral elements were used in a computational grid. All subsequent steps of the mount modification showed a positive effect of reducing the maximum stress values or their mitigation as dispersion over a larger area. The changes made it possible to eliminate potentially dangerous areas of stress accumulation points. The material used has a strength several times greater than the stresses occurring in the tested elements. It was found that no further modifications to the mount are required and it is possible to use the created geometry on the test stand.
FEM analysis of manufacturing of a hollow product with an outer flange in a four-stage cold forming process
Authors: Wójcik Ł , Bulzak T , Winiarski G 
Published: December 2021

Abstract
The paper presents the results of a FEM computer simulation of the cold forming process of a hollow sleeve forgings with an outer flange. Numerical simulations were carried out in DEFORM 2D / 3D. For the numerical calculations of the forming process the axisymmetric calculation module was used. As the test object, a tubular workpiece with an outer diameter of Ø50 mm and a wall thickness of 10 mm made of 42CrMo4 steel was used. The process of forming the rotary sleeve was conducted in four stages consisting of two technologies. The first stage of the research was the analysis and selection of parameters of the extrusion process, which was used for the first stage of forming. The processes of free extrusion and the use of a container were analysed. Furthermore different die angles and different wall thickness reductions were used. The products obtained in the extrusion process were upset in three conical blanks. The aim of the study was to analyse the numerical accuracy of the designed process of forming the hollow shaft with flange. The analysis of the results was based on the deformation intensity distribution maps, the Cockroft-Latham criterion distribution and the progress of the forming forces. On the basis of the conducted research, it was concluded that the presented process of forging a hollow product with a flange in four stages is possible to carry out correctly.
Modeling and optimizations of mixing and aeration processes in bioreactors with activated sludge
Authors: Zaburko J , Łagód G , Widomski M K , Szulżyk-Cieplak J , Szeląg B , Babko R 
Published: December 2021

Abstract
Mixing aimed at homogenization of the volume of bioreactors with the activated sludge is of great importance for the proper course of the wastewater treatment process. It affects both the efficiency of pollutants removal and the properties of the activated sludge related to its sedimentation. The mixing process in bioreactors can be carried out in different ways. In batch bioreactors in the aeration phase or flow bioreactors in aerobic chambers, mixing is carried out through aeration systems. These systems should aerate the activated sludge flocs for efficient biological treating of wastewater, as well as effectively homogenize the volume of the bioreactor. Hence, it is important to choose such a design of the aeration system and its operation settings that provide the amount of air ensuring the exact amount of oxygen for the implementation of technological processes, counteract sedimentation of sludge at the bottom of the reactor, are reliable as well as economical in operation (demand of electric energy). The paper presents the model studies aimed at optimization of the design and settings of aeration and mixing systems used in active sludge bioreactors.
Optimal Design of Antenna for Radio Frequency Energy Acquisition System
Authors: Li Xinzhe , Ren Ming , Tian Haoyang 
Published: December 2021

Abstract
At present, many sensors are gradually developing in the direction of ultra-low power consumption, miniaturization, and low cost, which makes radio frequency energy acquisition technology a popular research field with a wide range of applications. However, traditional sensors are generally powered by batteries, which greatly increases the size of the device. Furthermore, antenna is an important module for radio frequency energy acquisition, and optimization of its sensitivity and other performance is particularly important. This article uses HFSS electromagnetic simulation software to simulate antenna elements and arrays made of PTFE, and simulates various parameters. And optimization, an antenna array element whose port impedance characteristics and unit antenna gain both meet the design requirements is constructed. Finally, the gain of the 2×2 array antenna after parameter optimization is 13.8dB, which greatly improves the gain of the receiving antenna.
Selection of Weld Structure of Bogies Based on Sub-Model
Authors: Guo Shuo , Yu JianGuo , Su Shuaishuai 
Published: December 2021

Abstract
In order to effectively deal with the problems in the allowable fatigue strength data of weld joints of steering structures, it is necessary to carry out comparative tests and analyses according to various structural stress methods and data. Therefore, on the basis of understanding the applied strength standard of bogie welded structure in China, and aiming at the application of weld structural stress at the present stage, this paper constructs the fatigue diagram and S-N curve of Q345 weld seam based on the actual tested structural stress, and starts with the result study.
Application of Multi-dimensional Technology in Water Conservation Monitoring of Power Transmission and Transformation Production and Construction Project
Authors: Lei Lei , Wu Jian , Zhang Yapeng , Wan Hao , Bai Xiaochun , Liu Xin , Wang Liang 
Published: December 2021

Abstract
Under the background of the new era, as the production and construction projects of soil and water conservation began to fully promote the “integration of heaven and earth”, the traditional application technology has been unable to meet the needs of practical development, and the power transmission and transformation production and construction projects put forward higher application requirements. Therefore, on the basis of understanding the current implementation of soil and water conservation monitoring work, this paper analyzes how to reasonably use UAV technology in practical monitoring work according to the multi-dimensional technical means proposed in the new era, and conducts performance analysis according to the practical verification.
Research on Information Security Protection of Active Distribution Network Based on Trusted Computing
Authors: Liu Xuesong , Jin Chengming , Chen Zhiyong , Song Ge 
Published: December 2021

Abstract
In the continuous innovation and development of smart power grid in China, active distribution network as an important part, the corresponding information security protection work has received the attention of the whole society. On the basis of understanding the current operation of smart grid system, this paper analyzes and discusses the practical application cases by clarifying the safety protection and safe and credible protection schemes of active distribution network.
Composite Control Strategy of Output Current of LCL Photovoltaic Grid-Connected Inverter
Authors: Li Shengqing , Li Xinluo , Wu Qiang , Long Xiafei 
Published: December 2021

Abstract
In order to further optimize the output current harmonic suppression effect of photovoltaic grid-connected inverters, a composite control strategy of LCL type photovoltaic grid-connected inverter output current is proposed. This strategy combines proportional complex integral (PCI) control and repetitive control (RC) in parallel, draws a composite control block diagram, introduces a transfer function, and designs PCI and RC control parameters. Prove that the compound control can reduce current harmonics, achieved the purpose of reducing the steady-state error of the fundamental frequency. And adopts a new PCI composite control strategy, which helps to save the cost of the control system. By building the MATLAB/Simulink simulation platform and establishing the PCI+RC composite control model of LCL photovoltaic grid-connected inverter, the comparison of the simulation results shows that compared with the PI+RC control strategy, the total harmonic distortion rate of the grid-connected current is reduced by 25.77. %, significantly improving the quality of grid-connected current.
Research on High-Temperature Cooling Flight Test Technology of a Certain Type of Civil Aircraft Generator
Authors: Wu Jingtao , Cai Jin , Ma Ming 
Published: December 2021

Abstract
The high-temperature special flight test is one of the important special meteorological flight tests for civil aircraft airworthiness certification flight test, and generator high-temperature cooling flight test is also very important as the key flight test subject of high-temperature special flight test. The purpose of this paper is to summarize and study the airworthiness background, technical research, technical preparation, technical implementation, and data analysis results of a certain type of civil aircraft generator high-temperature cooling flight test, to provide guidance and help for subsequent civil aircraft generator high-temperature cooling flight test.
Design of High-efficiency LED Driver Power Supply Based on Improved Particle Swarm Optimization
Authors: Zhang Fanghui , Qiu Huimin 
Published: December 2021

Abstract
The photoelectric properties of LED are affected by driving current and ambient temperature. To solve the problem of light wane caused by excessive current and overheating, LLC resonant converter with soft switching was chosen as the main topology, improving the power efficiency, and reducing the heat of the LED driver. Firstly, the soft-switching conditions of the LLC resonant converter are analyzed, and the constraint equation is obtained. Then, an improved particle swarm optimization algorithm is proposed to optimize the resonant parameters. The weight of particles is dynamically and adaptively changed to balance the global and local optimization performance of particles. Finally, the controller is designed to realize constant current. This design improves the efficiency of the LED driver. At the same time, the light wane is effectively suppressed by stable output current, and the rationality of the selected parameters is verified by simulation and experiment.
Active Damper Frequency Division Control Method for Cluster Resonance of Photovoltaic Inverters
Authors: Li Shengqing , Huang Simin , Luo Zhaoxu , He Yuanming 
Published: December 2021

Abstract
Aiming at the harmonic resonance problem of photovoltaic inverter cluster system when it is incorporated into weak power grid, an active damper frequency division control method is proposed to suppress the harmonic resonance. Firstly, the voltage signal measured by the voltage transformer is separated according to the frequency, and then the harmonic conductance value of the frequency band is controlled respectively according to the harmonic voltage. Finally, the output current is feedback controlled by the generalized integral PI controller, so as to realize the impedance remolding of the photovoltaic inverter cluster system. This method can adjust the value of virtual conductance in different frequency band adaptively according to the harmonic voltage, so as to suppress the harmonic resonance problem of photovoltaic inverter cluster more effectively. The simulation results of Matlab/Simulink demonstrate the correctness and effectiveness of the proposed frequency division control method.
Research on Radio Frequency Energy Acquisition Technology Used in Partial Discharge Sensors
Authors: Li Xinzhe , Ren Ming , Tian Haoyang 
Published: December 2021

Abstract
To solve the energy supply problem of distributed sensor nodes for power equipment condition monitoring, the radio frequency energy acquisition technology scheme and low power consumption control method suitable for this type of sensor are studied. In the research of radio frequency energy technology, a high-gain radio frequency receiving unit is designed to convert a specific frequency high-frequency spatial electromagnetic wave into a AC small signal, and a radio frequency-voltage doubler rectifier unit is designed to convert the AC small signal into a DC signal and boost it, a supporting energy management unit is designed to control the energy interaction with the back-end sensor and provide a reliable and stable DC voltage to the partial discharge sensor. In terms of low-power control, the hardware adopts frequency-reduction detection and low-power devices, and the software proposes a work mode switching strategy, forming an ultra-low power design and application scheme for partial discharge sensors.
Research on Electromagnetic Force of Hybrid Electromagnetic Levitation Needle Driving System
Authors: Xiong Tao , Yin Wenshu , Li Dongdong , Zhang Chengjun , Zuo Xiaoyan 
Published: December 2021

Abstract
Hybrid electromagnetic levitation drive system is the core of the needle drive structure, and its performance directly determines the size of the needle drive force. According to the initial design results, the simulation model of the needle drive is established in the electromagnetic field simulation software Maxwell, and the influence of the structural parameters of the hybrid electromagnetic drive system:, the material of the iron core, the number of coil turns on its static characteristics is analyzed. The simulation results show that at the same height, when the isolation ring material is aluminum, the time for the permanent magnet needle to rise to the highest position is the shortest.
A New Type of Super-Sparse Matrix Converter with Γ Source and Its Characteristics Analysis
Authors: Li Shengqing , Yan Shi , Zheng Jian , Zhang Heng 
Published: December 2021

Abstract
To solve the problem of low voltage transmission in ultra sparse matrix converter (USMC), a novel ultra sparse matrix converter (USMC) is proposed. The new USMC topology contains of a Γ source boost circuit in the DC link. By increasing the output voltage of DC link, the inverter stage can output higher voltage, thus widening the range of voltage transmission ratio. Furthermore, combined with the SVPWM modulation strategy, the voltage transfer ratio of the new USMC topology is derived, which lays a theoretical foundation for the application of USMC. Finally, Matlab / Simulink simulation results verify the correctness and feasibility of the topology.
Research on Intelligent Monitoring and Maintenance Technology of Substation Based on Digital Twin
Authors: Wang He , Lin Peng , Hou Zhansheng , Sun Shijun 
Published: December 2021

Abstract
The design, research and development, test, operation and maintenance of power grid substation equipment are relatively independent. Related problems in each link cannot be comprehensively managed from the perspective of the full life cycle of equipment. Operation and maintenance personnel need to face data monitoring, network monitoring, equipment monitoring, business system monitoring, fault diagnosis and repair and other business scenarios. There are many types of information, complex association relationship, abstract and inefficient operation and maintenance information, “man-machine-object” can not be two-way cooperation and interaction, fault diagnosis and troubleshooting difficulties. Digital substation intelligent monitoring operational digital twin applications, digital intelligent substation operations provide operational monitoring service ability, realize the grid digital substation twin modeling and environment reconstruction, false or true merged superposition, two-way coordinated interaction, twin intelligence operations and panoramic visual monitoring, field devices for power grid operation maintenance, resource scheduling, and construction planning to provide guidance, Fully guarantee the safe and reliable operation of power grid equipment, realize the full life cycle management of power grid equipment, and improve the level of intelligence, visualization and digitalization of power grid.