bluuebunny/crossref_metadata_2025 huggingface dataset:
Shell-Model Study of Nuclear Weak Rates relevant to Astrophysical Processes in Stars
Authors: Suzuki IToshio , Shimizu Noritaka , Tsunoda Yusuke , Otsuka Takaharu , Nomoto Kenichi
Published: March 2023

New shell-model Hamiltonians which can successfully describe spin responses in nuclei are used to evaluate nuclear weak rates in stellar environments. The e-capture andβ-decay rates for the nuclear pair with31Mg-31Al, in the island of inversion, which have been pointed out to be important for the cooling of neutron star crusts, are studied by shell-model calculations with the effective interaction insd-pfshell obtained by the extended Kuo-Krenciglowa (EKK) method. The weak rates induced by the Gamow-Teller transitions between the low-lying states in the nuclear pair lead to a nuclear Urca process. The spin-dipole strengths and e-capture rates for78Ni are evaluated by shell-model with fullpf-sdgshells including up to 5p-5h excitations outside filling configurations of78Ni. The e-capture rates obtained are compared with RPA calculations and the effective rate formula. Weak rates for the second-forbidden transition in20Ne are evaluated by the multipole expansion method of Walecka as well as the Behrens-Bühring method within sd-shell. Difference in the rates between the two methods is found to be rather small as far as the conserved-vector-current (CVC) relation is satisfied. Possible important contributions of the forbidden transition to the heating of the ONeMg core by double e-captures on20Ne in a late stage of the evolution of the core and implications on the final fate of the core, whether core-collapse or thermonuclear explosion, are discussed.
Conjectured Hole States (7Be, 19F) and p-h states (8Be) of the CSM
Authors: Gai Moshe
Published: March 2023

The remarkable success of the Algebraic Cluster Model (ACM) to describe the N=Z even-even light nuclei, 8Be, 12C, 16O and 20Ne, and the neighbouring nuclei with one particle added, 9Be, 9B, 13C, 21Ne and 21Na, using the Cluster Shell Model (CSM), lead us to consider the phenomenology of data on conjectured hole states of the CSM in 7Be and 19F, and conjectured high lying particle-hole states (p-h) in 8Be.

We propose the first application of the Cluster Shell Model (CSM) of Della Rocca and Iachello to conjectured p-h states in 8Be. We demonstrate a few essential phenomenological features of the CSM in 8Be: 1) All predicted conjectured p-h states of the CSM, and only the predicted p-h states, are observed near thresholds and up to 19.5 MeV in 8Be. 2) The states are observed in the predicted order, with positive parity states below negative parity states. 3) Some of the conjectured p-h states are already known to have the predicted rotational structure of the deformed p-h states. 4) The rotational structures observed at high excitations in the conjectured p-h bands in 8Be, resemble the ground state bands of 8Be, 9Be and 9B, with similar moment of inertia.

Based on these observations we contemplate new measurements of the spectroscopy of 8Be at energies above 19.5 MeV, where our knowledge of states in 8Be is incomplete. We examine the observed B(M1)s and B(E2)s in these nuclei and contemplate a measurement of the B(E2) of the iso-baric Analog transition in 8Li.
Research on Intrinsic and Environmental Conditions Hazard Analysis Methods for Civil Aircraft
Authors: Yu Jie
Published: March 2023

SAE ARP 4761 stipulates that an area safety analysis must be performed in every area of the aircraft to ensure the safety requirements of the equipment. The study proposes the Intrinsic Hazard Analysis and environmental conditions hazard analysis methods to identify potential neighboring hazard sources, assess the weakness of the area, and solve the problem of incomplete input of area safety analysis. The IEHA analysis method has been verified and applied in the actual type of work, which plays the role of systematic and comprehensive identification of hazard sources and discovery of potential risks, and has practical engineering application for the development of domestic large aircraft. It provides a good theoretical basis and technical reserve for establishing the method and process of civil aircraft safety design verification.
Research on Cutting Parameters Database Based on Spacecraft Product Characteristics
Authors: Liu Hanliang , Yang Kai , Zhao Wei , Hu Xingping , Feng Changxi , Wu Di , Diao Zhenkuan , Qiao Kun , Wu Fei
Published: March 2023

Cutting parameters affect the production and processing efficiency and the quality of products. The characteristics of single-piece and small-batch production of spacecraft products result in a large number of cutting parameters. Due to the lack of centralized management methods, cutting parameters in the production site are not unified, which seriously affects the processing efficiency and quality of products. In response to a large number of cutting parameters and the lack of centralized management, the production resource library is completed by establishing a spacecraft product feature pedigree. Taking the product characteristics as the carrier, the production resources as the optional factors, and the forces in the cutting process as the evaluation criteria, the whole life management mechanism of cutting parameters is established to unify the cutting parameters in the production process and complete the establishment of the cutting parameter database. The interface between the programming platform and the cutting parameters library is developed for a low reuse rate of cutting parameters. With typical features as the carrier, the cutting parameters are packaged and transmitted to the programming platform to provide reliable cutting parameters for feature automatic programming, which improves the reuse rate of cutting parameters and simplifies the numerical control programming operation. The results show that the reuse times of cutting parameters are more than 8000 times, effectively ensuring the machining efficiency and quality consistency of products.
Numerical Investigation of Cooling Characteristics of a Double-sided Composite Impeller with a New Micro Gas Turbine
Authors: Huang Jiaxin , Zhang Cheng , Long Yongqiang
Published: March 2023

In order to achieve a micro gas turbine engine with higher thermal cycle parameters and higher aerodynamic performance, a double-sided composite impeller has been designed innovatively based on structures combined, thermal cycle process integration, and existing impingement cooling technology with the help of additive manufacturing technology, which is expected to increase the turbine inlet temperature and break the material limit. The double-sided composite impeller is numerically simulated by the method of gas-thermal coupling. The results showed that: First, compared with the turbine without cooling, the maximum turbine wall temperature and average turbine wall temperature of the turbine with impingement cooling technology decreased by more than 166.33K and 213.79K, respectively, and the minimum cooling efficiency and the average cooling efficiency of the turbine with impingement cooling technology increased by more than 34.32% and 46.8% respectively. Second, the physical property differences of nickel alloy materials in the same category have no obvious influence on the cooling characteristics of turbines. Finally, for GH4220 material, the turbine inlet temperature can be increased by more than 520K when the turbine material is kept in a stable working temperature range. This study opens the way for the higher turbine inlet temperature or the use of low-cost, lightweight materials such as titanium alloys.
Kinematic Analysis of 5-axis CNC Laser Processing Machine Based on GSN Control Card
Authors: Sun Yingjie , Yao Kun , Yuan Minghai , Mao Kefu
Published: March 2023

The five axis CNC laser machining machine is widely used in the processing industry with high efficiency and precision and other advantages. Based on the basic principle of kinematics theory on the multi-body system, this paper describes the homogeneous coordinate transformation law of the five-axis laser machining machine tool based on GSN control card, and analyzes the solution of the motion trajectory and converts it into the incremental data of the position of each axis in the coordinate system of the machine tool, which solves the correctness, universality and automation of the numerical control system. It provides a powerful help for the five axis CNC laser machining machine based on GSN control card.
Self-gravity Simulation Method Based on Distance-controlled Mesh Encryption
Authors: Lin Zhiyong , Qiang Li’e , Zhao Shuhong
Published: March 2023

In the space-borne gravitational wave (GW) detection mission, the self-gravity noise caused by the deformation and residual jitter of the satellite platform is an important source of the total acceleration noise. In order to estimate the magnitude of the noise, the gravity acceleration and gravity gradient at the TM need to be carefully evaluated, which requires high accuracy of the self-gravity simulation. After the satellite component is divided into several mass cells by using the grid generation technology, if the number of cells is too small, the total gravity and gravity gradient obtained by superimposing the gravity between each cell and the TM will deviate greatly from the true value. On the other hand, directly densifying all single cells will produce a large number of new cells, reducing the simulation efficiency. Aiming at these problems, we present here the self-gravity simulation method based on distance-controlled grid refinement, analysis of subdivision unit size, unit and the distance between the test quality and the relationship between the simulation error, select the appropriate scaling factor to encrypt the initial mesh. It is expected to reduce the number of units on the premise of meeting the precision requirements of self-gravity simulation and then improve the simulation efficiency. The model test shows that when the grid cells are hexahedral, compared with simulation results using uniformly mesh encryption, the accuracy of the self-gravity simulation results based on distance-controlled is an order of magnitude higher, and the total number of grid cells used is less.
Model Predictive Control of Aerodynamic Heat Simulation Heating System with Discrete-time Linear Extended State Observer
Authors: Bai Zhiqing , Zhang Guangming , Wang Gang , Deng Ke , Lv Xiaodong
Published: March 2023

In this paper, a novel Model Predictive Control (MPC) scheme based on discrete-time Linear Extended State Observer (LESO) is proposed for the Aerodynamic Heat Simulation Heating System (AHSHV). First of all, the mathematical model and the predictive model of AHSHV are established, while the unknown terms of the predictive model can be observed by discrete-time LESO. Next, the cost function is constructed for rolling optimization control, and the rolling optimization replaces global optimization with local optimization. Each local optimal control is a feedback correction, and the combination of rolling optimization and feedback correction ensures the performance of the control system. Finally, the simulations and comparison results verify that the MPC scheme proposed in this paper performs better than the traditional PID control scheme in terms of static characteristics, dynamic characteristics, and robustness.
FPGA-Based Time-to-Digital Converter for Pulsed Laser Ranging
Authors: Wu Qishen , Zhang Yan
Published: March 2023

This paper implements a Time-to-digital Converter (TDC) in a field-programmable gate array (FPGA), which is made for a single-photon-counting-based pulsed laser ranging system. The fine time is measured by the Tapped Delay Line (TDL) constructed in an internal dedicated carry chain of the FPGA. The length of the TDC is longer than one clock period, and the whole CARRY4 is utilized as a delay unit. The proposed TDC is made up of the fine time measurement module, encoder, coarse time counter, and data transport module, which are achieved in a resource-tensed FPGA Xilinx-ZYNQ. As this paper is done in a shared FPGA, the presented TDC can replace the ASIC-TDC GP22 as the TOF measurement module. By measuring the same time interval and modifying the fixed error in TDC, the results show that the time resolution can reach 53 ps. Compared with the ASIC-TDC GP22, both linearity and measurement range are improved in the proposed TDC, which makes the pulsed laser ranging system more flexible and integrated.
Influence of Characteristic Parameter on Extrusion Stress with Working Surface of the Zigzag-shroud Blade
Authors: Li Shifeng , Zhang Jianqiang , Chen Suling
Published: March 2023

Taking a high aspect ratio and low-pressure turbine blade as an example, the research on the influence of zigzag-shroud characteristic parameters on the circumferential tightness and extrusion stress of the working surface, the comprehensive influence law of the zigzag-shroud key parameters on blades strength can be obtained to reduce the zigzag-shroud stress level to the allowable range. It is found that the engagement angle (β) and pre-torsion angle (△β) are the two key parameters to determine the tightness of the contact surface. When the engagement angle is 40.9°, the extrusion strength of the zigzag-shroud working surface is the highest. At the same time, it is found that the pre-torsion angle and circumferential degree (△S) are proportional to the extrusion stress of the working surface, and there is an “optimal window” for both circumferential degree and pre-torsion angle. The best circumferential degree is 0.22 mm, and the optimal pre-torsion angle range is from 30’ to 1° by the calculation model.
Multi-airport System Route Network Optimization Based on Differentiated Positioning
Authors: Wang Xueyao , Guo Xin
Published: March 2023

Air routes in China’s existing multi-airport system are unreasonable and homogeneous, leading to a significant gap in utilization between different airports and a waste of airport resources. One differentiated positioning model is proposed to optimize the air route network to solve the above problems. Balanced development of airports and passenger costs are considered in the model. Finally, the model is validated using the 2019 route network dataset in the Beijing-Tianjin-Hebei multi-airport system (BTH MAS). The optimization results for the multi-airport system show an average increase of 15% in airports utilization, an average increase of 6% in the differentiated realization rate, an 8% reduction in the average cost of passenger travel fees, and a 17% reduction in route repetition with no reduction in the number of connections to destination airports.
Research Progress in Numerical Simulation of Aircraft Wing Flow Field
Authors: Ma Zongren , Tang Zhengyang , Wang Ruixuan , Yu Zhuoyuan
Published: March 2023

Computational fluid dynamics has important application value and theoretical significance in engineering. Fluid mechanics has emerged as a way out of many engineering design problems. In recent years, applying fluid mechanics in the aircraft field has brought a breakthrough to problems that could not be solved previously. This paper mainly introduces the development history of the application of computational fluid dynamics in the direction of the wing and the specific application of this technology in the numerical simulation of the wing flow field. The aerodynamic characteristics of aircraft wings are related to the flight performance of the aircraft. The influence of wing aerodynamic characteristics, wing lift drag coefficient, and wing noise is a hot research issue. The influence of flow field research methods (such as numerical simulation) on the optimization and improvement process of the wing is analyzed, and the numerical results and simulation results of the flow field are found. The future development trend of the wing is proposed. Finally, it is believed that changes in airfoils will have a significant impact on aircraft performance.
Spatial and Temporal Distribution of Near-Surface Methane Concentration in Northwest China Based on GOSAT Satellite Data
Authors: Lian Haotian , Shi Xiaoqi , Shen Yufei , Wang Chuyu
Published: March 2023

Methane (CH4) is a common greenhouse gas that plays an important role in global warming and affects people’s production and life. In order to study the temporal and spatial distribution situation of methane concentration in northwest China (Shaanxi, Gansu, Ningxia, Xinjiang, Qinghai), this article used L4B level data products monitored by GOSAT satellite from 2009 to 2019 to study the temporal and spatial distribution characteristics of near-surface methane concentration in northwest China. The results of the analysis were as follows. Firstly, the annual average concentration of near-surface methane in northwest China was in a rising state, and the maximum annual average concentration increment was in 2016. Secondly, seasonal variation of methane concentration: Autumn>Summer>Spring>Winter. Finally, spatial variation of the annual average methane concentration: Shaanxi, Ningxia, and southern Gansu>northwest Xinjiang>other northwest China regions. The methane concentration decreased from the bottom to the top gradually.
Ultra Short-term Load Optimal Dispatching Method for Micro Grid Considering Demand Side Response
Authors: Zhu Tao , Yang Kang , Li Lanqing , Cui Zhanfei , Lu Qiuyun
Published: March 2023

With the development of the economy, the electricity demand is also increasing. However, the traditional micropower supply bears the problems of excessive load growth and unstable voltage. Therefore, this paper takes power generation as the research object. First, the principle of output optimization based on schedulability, reserve capacity, and intermittent operation frequency of units is analyzed. Then, the relationship between the optimal solution and the minimum power consumption time is calculated by establishing a mathematical model to solve the algorithm, and the difference between the two results is compared. Finally, the power system is simulated on Matlab software, and the method and effect are verified by numerical simulation. The simulation results show that with the same microgrid power configuration, there is a 3.5% load transfer at time-sharing prices and a 6.4% load transfer at real-time prices through price-based demand response. The optimization objective of demand response, namely the cumulative sum of the difference between new energy power generation and load, is 15312 kW · h per year when the fixed price is implemented, 54134 kW · h is for the time of use price, and 451645 kW · h is for real-time price. The response effect of real-time price is optimal.
Vibro-acoustics time domain FEM-BEM analysis of a Titian Stradivari violin: the role of the bridge
Authors: Kaselouris Evaggelos , Dimitriou Vasilis
Published: March 2023

The acoustic behaviour of the violin is defined during manufacturing since the vibrational acoustic properties of the instrument are related to the top plate’s vibrational modes in a direct way. An important component of the violin assembly is the bridge. The bridge transfers the excitation forces from the strings to the soundboard via the bridge feet and acts as a sound filter. In this study the Titian Stradivari violin CAD geometry of the soundboard, including the f-holes and bass bar, and the bridge is modelled, and time domain coupled finite element method-boundary element method, vibro-acoustic, simulations are performed to analyse the interference of the instrument’s sound with its structural components. A comparison of the vibroacoustic behaviour for the soundboard with and without the bridge enlightens the crucial role of the bridge. This initial computational approach will be extended, with similar studies on the role of every structural component of the violin individually, aiming to decode the full violin soundbox vibroacoustic behaviour and provide key insights for violinmakers on how structural changes affect the quality of the emitted sound.
Technologies and Applications of Pipeline-type Oil-gas-water Separation
Authors: Zhang Jun , Su Lide , Han Jipu , Sa Qier , Wang Juntao , Chai Weichen , Li Bingyu , Zhong Xingfu
Published: March 2023

The separation of oil, gas, and water mixture is an important process in the production of crude oil. Traditional separation tanks are large, heavy, long in separation time, and high cost to manufacture. This paper introduces a separation technology with the main characteristics of the pipeline structure. This technology uses the principles of centrifugation, expansion, air flotation, and gravity separation. Pipes and other equipment are the core equipment, which has the advantages of flexible process composition, small footprint, and high separation efficiency. This technology can be used for rapid oil, gas, and water separation, solving the problems of expansion, upgrading old oilfield stations, realizing the purpose of re-injection of water in-situ, energy saving, and reducing emissions.
Analysis of Aircraft Parking Stability Based on Atmosphere Boundary Theory
Authors: Liu J , Ge J L , Yang H , Chen W S , Wu J H , Qu Q L
Published: March 2023

Based on numerical simulation technology, the aerodynamic load research of civil aircraft parked on the ground is conducted. The CRM model parked on the ground is established by CFD software. Based on the atmospheric boundary layer theory, the seven incoming flow conditions for numerical calculation are designed. And the aerodynamic loads’ change of the aircraft model is calculated when the -90° sideslip angle. The result shows that the mooring load on the nose landing gear mainly comes from the longitudinal load caused by the upwards pitching moment on the flat tail and the lateral load caused by the yaw moment; since the rolling moment coefficient is less than the pitching moment coefficient by two orders of magnitude, which hardly affects the mooring load. The study provides a reference for reducing the mooring load of civil aircraft under heavy wind conditions.
Structure design of a radar display console muffler
Authors: Kang Ji , Zhang Liang Juan , Liu Sheng Sheng , Lv Zhao Hui
Published: March 2023

Radar display console is an equipment which is closely associated with people as a medium of human-computer interaction. However, for the sake of heat dissipation, draught fans in display console make continuous noise when radar is on operation, the noise dose harm to human health. In order to reduce the noise, an impedance compound muffler is designed in this paper, and then the acoustic characteristics of muffler is studied by simulation method. In the end, the simulation results are verified by means of noise spectrum analyser, as a result, the muffler obtains good silencing effect and the maximum sound level of the radar display console is reduced by 3dB.
Underwater source localization based on a matrix distance measurement
Authors: Guo Yuyan , Gong Xianyi
Published: March 2023

In this paper, a matrix distance measurement is introduced to underwater source localization. Matched field processing (MFP) and beamforming(BF) are widely used methods that both make the correlation between data and copy vectors. We proposed statistical matched field processing (SMFP) and statistical beamforming (SBF) in this paper that measure the distance between data and copy cross-spectral density matrices (CSDMs) in place of the correlation of the two vectors. As CSDM is Hermitian and positive semidefinite, Riemann distance is suitable. Matrix-matrix comparison increases the dimension of the system compared with vector-vector correlation, so as to include environmental uncertainty. SMFP and SBF are compared with conventional matched field processing (CMFP) and conventional beamforming (CBF) respectively in simulations. The results show that SMFP and SBF achieve satisfactory localization performances.
Numerical investigation of submerged impinging jet based on different turbulent models
Authors: Ge Jie , Wang Chuan , Yao Yulong , Chen Xinxin
Published: March 2023

In today’s world, the loss of effective storage capacity caused by reservoir siltation has reached 50 billion cubic meters per year. As a high impact and simple water jet technology, submerged jet impact can have a powerful washout effect on submerged sediment. On this article, the submerged impinging jet is numerically computed with importing the Wray–Agarwal (W-A) turbulence models in FLUENT. Then, the streaming field analysis of the jet under different conditions is carried out and compared to the PIV test outcomes. To validate the effectiveness of the W-A turbulence models for predicting the streaming field of submerged impinging jet. The results show that, relative to other turbulence models, the calculated findings of the Wray–Agarwal turbulence model are in much closer accordance with the test data.
Study on the relationship between intercalation rate of melt-blown nonwovens and process parameters based on correlatio n analysis
Authors: Guo Hongze , Gao Ke , Liu Yingchang , Yu Yue
Published: March 2023

The melt-blown nonwoven material is an important raw material for mask production, which has attracted much attention. There are many technological parameters for the preparation of intercalated melt-blown nonwovens, and there are interactive effects among the parameters, which are more complicated after intercalation airflow. In order to better study the regulation mechanism of product performance, our team established a mathematical model of process parameters with structural variables and a mathematical model of structural variables with product performance based on 25 groups of control experiments and experimental data of fixed intercalation rate. Also, we tried to solve different problems with the models. Based on correlation analysis and partial correlation analysis, the preparation process parameters of intercalated melt-blown nonwovens are explored to some extent, and the influence of intercalation rate is analyzed, which provides a relatively reliable theoretical basis for industrial production.
Design of TaCu alloy coating for orthopaedic materials and study on dissolution behavior of copper ions
Authors: Yu Xiaoming , Guo Zhaoxin , Yi Haowei
Published: March 2023

In this study, tantalum copper (TaCu) alloy coating was designed and fabricated by the chemical vapor deposition (CVD) method, while the process was explored through COMSOL Multiphysics software. The influence of deposition temperature on coating quality was studied in combination with our previous work. In addition, the galvanic corrosion behavior of TaCu coating in Hank’s solution was simulated through this software. The COMSOL Multiphysical software can be used to simulate the process that TaCu coated on the surface of titanium(Ti) alloy substrate by chemical vapor deposition. The deposition quality was affected by the direction of the deposition airflow. Cu ion dissolution makes the coating thickness decrease uniformly, Cu ion dissolution accelerates due to galvanic corrosion, and the antibacterial ability of the coating can be improved due to Cu ion dissolution.
Adsorption and diffusion of sodium on boron-doped carbon nanotube
Authors: Fan Kaimin , Ni Jiangfeng , Tang Jing , Ding Ruiqiang , Zhu Hongwei
Published: March 2023

The first principles have been performed to investigated the performance of the boron-doped (B-doped) carbon nanotube for sodium-ion batteries. The Na adsorption energies at H1 and B1 sites are -2.821 eV and -2.523 eV, which have decreased by 0.985 and 0.846 eV as compared with pure CNT, respectively. The results indicate that B-doped CNT is beneficial for Na adsorption. The Na diffusing between two hollow sites across the TC1 and B1 sites shows low barriers of 0.309 eV. Additionally, the projected density of states (PDOS) shows that B-doped CNT exhibits metallicity and non-magnetic properties with Na adsorption, which is beneficial for electron transfer. The PDOS move towards higher energy levels, which is beneficial to enhance conductivity. These results suggest that B-doped CNT shows high performance as anode for sodium-ion batteries.
The Novel Nanoscale Compound and its Suppressing Lattice Thermal Conductivity in Cu-Ni-Sn-S systems
Authors: Liu Shuqiang , Zhang Yingjie , Li Enliang , Li Chao
Published: March 2023

The microstructure research of eco-friendly thermoelectric material is key to optimizing thermoelectrical properties. The microstructures of Cu2Ni0.1Sn0.9S3 ceramic with low thermal conductivity were studied using X-Ray diffraction, transmission electron microscopy and X-ray energy dispersive spectroscopy. The cubic metastable Cu26-x
Ni4+x
Sn4S32 nanoprecipitates embedded in the matrix were observed. This metastable nanoprecipitate shows certain orientation relationships with the matrixs and unclear interface area. Finally, the occupation semiorder of Cu atoms in Cu26-x
Ni4+x
Sn4S32 nanoprecipitates, coherent heterointerfaces between Cu26-x
Ni4+x
Sn4S32 and matrix can scattered phonon of similar wavelength to suppress lattice thermal conductivity.
Liquid Concentration Measurement Based on Liquid Contact Angle
Authors: Wang Xiahui , Ye Wenjie , Chen Xiye , Chen Qinghua , Xu Guowang , Liu Yukuai
Published: March 2023

Different concentrations of the same liquid or liquids with different solutes have different surface tensions. The macroscopic phenomenon is that they have different wetting effects on the same solid surface. The liquid contact angle can describe the wetting effect. Therefore, this paper proposes a method for measuring the liquid concentration using the liquid contact angle. A glass plate with a hydrophobic layer and an angle-measuring device forms the detection part. The glass plate is placed horizontally, and the solution to be tested is dropped on the surface of the glass plate. Solutions with different concentrations have different liquid-solid interfacial tension and liquid-gas interfacial tension, resulting in different liquid contact angles, which can achieve rapid and accurate measurement of solution concentration. Experiments show that the liquid contact angle of ethanol solution decreases with the increase of liquid concentration. Different volumes of ethanol solutions with the same concentration have substantially the same liquid contact angle. This experimental method has the advantages of being simple and easy to operate, having a wide range of applications, not easily limited by the type of detection solution, having a large concentration measurement range, having less sample usage, free from electromagnetic interference, and having real-time online detection.
Simulations of Magnetic Field Variations Around Rectangular Defects of Ferromagnetic Materials
Authors: Jorge Montes de Oca‑Mora Natanael , María Woo‑Garcia Rosa , Elizabeth Vázquez-Valdes Suany , Leobardo Herrera‑May Agustín , Sánchez Adrián , Arturo Cerón‑Álvarez Carlos , Restrepo Johans , Algredo‑Badillo Ignacio , Lopez‑Huerta Francisco
Published: March 2023

The ferromagnetic structures require techniques of defects inspection for their structural monitoring. The early detection of these defects can prevent structural failures that cause economic losses and environment damages. Herein, we present a model for numerical simulations of the magnetic field variations around rectangular defects in ferromagnetic materials by Python programming language. These simulations can predict the behavior of the magnetic field variation caused by rectangular defects considering the study of the magnetic domains of the ferromagnetic material. The numerical simulations of magnetic field around three rectangular defects with different depths (1, 3, and 5 mm) and the same width of 3 mm are studied. The results of the numerical simulations agree well with the behavior of cracks. The proposed model can be used to estimate potential structural failures in ferromagnetic structures.
Investigation of the bright and dark line on the inner wall of a thin-walled copper tube by drawing with a floating plug
Authors: Liu Jinsong , Li Wang , Chen Dayong
Published: March 2023

In this paper, it was investigated that the defects of the bright and dark lines on the inner wall of a thin-walled copper tube by drawing with a floating plug based on analyzing the stress distribution. The experiments were conducted by employing a stereomicroscope, metallographic microscope and scanning electron microscope, respectively, meanwhile the three-dimensional finite element was applied to study the defect. It was demonstrated by the research results that the large gap between the sizing section of the plug and the outer die caused the inner wall bright and dark lines. The wall thickness was increased when the tube passed by the area without inner support which gave rise to local material uplift along the radial direction. The raised material became folds due to the effect of “leveling” when the tube pass by the conical section and the sizing sections. The fold was the essence of the bright and dark line by macroscopic scale observation. The bright and dark line was ultimately eliminated by adopting the drawing die with reasonable geometrical parameters according to experimental and simulated results.
Study on mechanical properties of PVC modified by new core-shell toughener
Authors: Chang Jun , Jin Meng-yue , Wang Bin , Hu Yu-hong , Zheng Wen-jie
Published: March 2023

To expand the application field of PVC and make PVC resin high-performance, much research has been done on the toughening modification of PVC at home and abroad. ACR tougheners with different core-shell ratios were prepared by core-shell emulsion polymerization, which was used to blend PVC resin. In the experiment, the tensile and impact properties of PVC/ACR blends were tested and the fracture morphology was observed. The impact properties of PVC blends with toughened particles with different core-shell ratios were investigated and compared with the commercial ACR-401 toughener. The best combination of toughening effect was obtained: when the PVC/ACR blend ratio was 100:3.5, the tensile strength of PVC toughened by ACR7030 core-shell particles was 22.78MPa, and the impact strength was 8.67 kJ/m, which was superior to the commercial ACR-401 toughener. Therefore, ACR7030 can significantly enhance the mechanical properties of PVC, and the toughened PVC shows ductile fracture.
Design of Loading and Unloading Mechanism of Spring Steel Cloth Fixture for Computer Embroidery Machine
Authors: Yin Haibin , Long Dekun
Published: March 2023

At present, the computer embroidery machine industry mainly uses manpower to disassemble the spring steel cloth clamp, which is very inefficient. This research designed a spring steel cloth clamp loading and unloading mechanism to solve this problem. First of all, the scheme of the loading and unloading mechanism of the spring steel cloth clamp is proposed. The mathematical model is established, and the simulation verification is carried out on this basis. Then the structural design is carried out. Finally, the prototype of the loading and unloading mechanism of the spring steel cloth clamp was trial produced, and continuous loading and unloading tests were carried out. The results show that the loading and unloading mechanism can automatically and continuously load and unload the spring steel cloth clips, meeting the design requirements. It also provides a solution for the embroidery machine industry to solve the time-consuming problem of manually loading and unloading spring steel cloth clips.
Experimental Research on Pipeline Corrosion Monitoring Technology Based on FSM
Authors: Qi Yonggang , Duan Rujiao , Fu Zhiqiang , Shi Xiushan
Published: March 2023

The field fingerprint method (FSM), a new online corrosion monitoring method, has a good application prospect. Of all the corrosion defects of pressure pipes, local small corrosion pits are the most commonly seen, and it is also the focus of FSM research. Based on the FSM method, this paper conducts experimental research on the common round and rectangular small corrosion pits of pressure pipes. The results show that the FSM method is sensitive to small volume defects, and the small corrosion pits with the minimum detectable depth of 0.5 mm can accurately reflect the defect growth process, this being of great significance to the safe operation of pipelines.
Bending of shape memory alloy nanobeams incorporating surface effects based on the Euler-Bernoulli beam model
Authors: Li Shoubao , Jia Xiaoli , Zheng Lei , Ke Liaoliang , Yang Jie , Kitipornchai Sritawat
Published: March 2023

Shape memory alloys (SMA) are widely used in micro-electro-mechanical systems due to shape memory effect and hyperelasticity. The surface effects on mechanical properties cannot be ignored because of their small structure size. Based on Euler Bernoulli beam theory and Gurtin-Murdoch surface elasticity theory, the influence of tension-compression asymmetry factors on SMA beams is considered, and a phase transformation mechanical model of SMA nanobeams considering surface effects is established. The effects of surface effects on load, curvature and neutral axis displacement are investigated The study demonstrates that regardless of whether considering the surface effect, the neutral axis displacement initially increases and subsequently decreases with the growth of the dimensionless bending moment. The neutral axis displacement of nanobeams can be significantly affected by taking surface effects into account. When considering the surface effect, the difference in neutral axis displacement of the nanobeam increases as the nanobeam’s size diminishes. Neglecting surface effects will underestimate the bending stiffness of the microbeam.
Failure Hazard Assessment of Three Gorges Ship Lift Drive System Based on Combined Weighting and TOPSIS Method
Authors: Chen Zhuo , Li Quangen , Li Xuefei , Li Zhiyuan , Liu Zhongming , Li Youhua
Published: March 2023

As the core subsystem of the ship lift, the drive system of the Three Gorges ship lift provides power for the operation of the ship lift, and its failure will directly affect the stable and safe operation of the ship lift. In view of the shortcomings of the existing evaluation methods for the failure hazard of the Three Gorges ship lift drive system, such as strong subjectivity and unreasonable weight of evaluation indexes, a failure hazard evaluation method for the Three Gorges ship lift drive system was proposed based on combined weighting and TOPSIS method. The effectiveness and feasibility of this method are verified by simulation of the Three Gorges ship lift drive system, which provides a new evaluation method for failure hazard analysis of key components of the Three Gorges ship lift.
The interactions between incoming shot flow and structural target in a Flap Shot Peening process
Authors: Feng Ruoqi , Lin Musen
Published: March 2023

A novel numerical modeling approach capable of computing and simulating the Flap Shot Peening (FSP) dynamic process of industrial interest was proposed by the coupling of the Discrete Element Method (DEM) and Finite Element Method (FEM). During the process of shots impacting the metallic target, the shot flow and the target were respectively modeled by DEM and FEM, and the interaction between the shots and structure was efficiently evaluated by DEM-FEM. This approach can be employed to rationally control and regulate the FSP multiple parameters, which would induce an appropriate distribution of Compressive Residual Stress (CRS) within the target to provide additional resistance to the treated component. In this paper, a benchmark was first performed to verify the computational method successfully. Further, the influence of variant mass flow rates on the target was also investigated. The result shows that low mass flow rates can be replaced by a higher mass flow rate in case both were able to generate a similar shot effect.
Study on the Influence of Tool Tip Radius on the Tooth Root Strength of Helical Cylindrical Gear
Authors: Lu Daixing , Sha Jiajia , Shen Ye
Published: March 2023

The bending fatigue strength of the tooth is an important index to measure the bearing capacity of the gear. The tooth root transition curve has a great influence on the bending strength of the gear. The profile of the tooth root transition curve depends on the shape of the tooltip. Therefore, the geometry of the tooltip must be considered in the simulation process of tooth profile generation. Contact analysis of helical gears with accurate geometric models is carried out in this paper. After generating tooth profiles machined by tools with different tip radii using MATLAB software, the three-dimensional model of involute helical cylindrical gears is established in CREO, and the stress distribution of gears under diverse load conditions is analyzed by FE software. In the end, it is concluded that the size of the tooltip fillet radius has a great influence on the maximum bending strength of the tooth root, and the strength of the tooth root decreases by increasing the tool tip radius.
A tilting system design and simulation of ground penetrating radar
Authors: DeKun Chen , Yuan Xue , SiYuan Tao , Peng Lan , NianLi Lu
Published: March 2023

In this paper, a tilting system of ground penetrating radar by 5R1C 6-bar linkage mechanism is proposed. The kinematic function of hydraulic cylinder and the output angle is given in explicit format. The quasi-static formulation of the tilting system is proposed to calculate the shaft and revolute force. The simulation of mechanism via ADAMS and an experiment is made to verify the design. The maximum stress is exposed in curved shaft and the worst working condition is the tilt condition. It proves the validity of tilting system that both mechanism and hydraulic system work well in the loading condition and unloading condition.
Design of High Energy Single Longitudinal Mode 355 nm UV Laser
Authors: Li Tianzhi , Guo Chuan , Zhang Chaofan
Published: March 2023

355 nm laser is a widely applied light source, of which the two features mostly used are the damaging effect and propagation characteristic in the atmosphere. Thus, higher laser energy has always been required to perform better damage and provide further propagation range. We demonstrate high energy single longitudinal ultraviolet (UV) laser using a nonlinear optical crystal of lithium triborate (LBO) cut at θ=90° and φ= 37° with sizes of 10 mm × 10 mm × 30 mm in type I phase-matching, the source light from a single longitudinal mode (SLG) inject master oscillator power amplifier (MOPA) operated at a repetition rate of 5 Hz with a pulse duration of 10 ns. The maximum output energy of 0.308 J of 355 nm UV laser was reached through a total pump energy of 1.82 J 1064 nm and 532 nm laser with an nonlinear conversion efficiency of 16.9%. The experimental results prove that the LBO crystal is a reliable candidate for high-energy UV laser generation. The output high energy 355 nm laser has great application potential in material processing, microchip manufacturing and remote sensing.
Design of single cycle current control method based on single-phase full bridge inverter circuit
Authors: Zheng Yan , Sun Jiyuan , Li Pin , Tian Chunlin
Published: March 2023

To achieve accurate control of the large inductive load, a single-phase full bridge inverter circuit topology with a simple structure is proposed. The current control on inductive load is realized by using the single-cycle control method, and the size and direction of the current can be adjusted at any time. The loading part is equivalent to the coil and resistance, the control principle of the circuit is analyzed, and the calculation formula of the duty cycle is calculated. The simulation results show that the designed circuit structure can control the current with a large inductive load
Research and design of a deformation monitoring system for the platform and canopy of a railway station
Authors: Xia Li Yin , Yuan Ma Yin
Published: March 2023

In this paper, the deformation of the platform and canopy of a high-speed railway station is studied, and an online monitoring system for platform canopy deformation is designed to solve the problem of online monitoring of platform canopy deformation. Due to the conventional one-dimensional measurement has been difficult to meet the needs of high-speed railway industrial production and daily life. Nowadays, laser radar and binocular cameras for three-dimensional data measurement have gradually emerged. At present, there is almost no three-dimensional data acquisition equipment with high measurement accuracy, low price, and a high degree of automation in the market. Given the lack of this equipment in the market, this paper presents a three-dimensional data acquisition system based on a laser rangefinder. By collecting, processing, and analyzing the data of the platform and canopy, the purpose of prediction can be achieved, and then the abnormal response, damage, and degradation of the structure can be found in time. The study shows that the monitoring system is helpful to detect deformation and give early warning, and effectively prevent the occurrence of hazards.
Optimization Design of Thin Wall Angular Contact Ball Bearing Based on MATLAB Genetic Algorithm
Authors: Chen Yulian , Li Junwen , Chen Chanyuan
Published: March 2023

The bearing for industrial robots is desired to have a long service life. To address that, an optimization study was conducted on a thin wall angular contact ball bearing used for a robot. Firstly, an optimization model was established with the basic rated life as the objective function and the curvature radius coefficient of the inner ring groove, curvature radius coefficient of the outer ring groove, ball diameter, pitch diameter, and the number of balls as the design variables. Then, taking the angular contact ball bearing ZR76/82C as an example, the optimization model was solved quickly based on a genetic algorithm via MATLAB software in two ways: calling the ga function and optimization toolbox, and the optimal structural parameters of the bearing were obtained. After the optimization, the basic rated life of the bearing was increased by 52%. The orthogonal test optimization design method was applied to validate the calculations, and the validation results showed that the two optimization results were very close to each other. The results show that the two approaches based on MATLAB genetic algorithm are efficient and feasible for solving optimization issues, and are of reference value for the study of solving other optimization issues.
Methods for Non-destructive Testing of Welding Residual Stresses in Aluminum Alloys
Authors: Liu Huaying , Gan Shiming , Zhang Jiaxin
Published: March 2023

There will be large residual stress after welding, and the residual stress will affect the service life of the aluminum alloy welding structure. Therefore, aluminum alloy welding residual stress needs to be accurately detected. Compared with the lossy method, the nondestructive testing method can produce negligible damage to aluminum alloy, which will not affect the reuse of aluminum alloy and can detect the residual stress. This paper summarizes the nondestructive testing methods of welding residual stress in aluminum alloy and their advantages, disadvantages, and applicability, which lay a foundation for rapid nondestructive testing of welding residual stress in aluminum alloy.
Noise source separation and identification of excavator cab based on EEMD-PCA-ICA-ST
Authors: lin Jianpei , Zhu Jianxin , liu Qiang
Published: March 2023

In order to effectively separate and identify the noise source of excavator cab, this paper adopts the methods of ensemble empirical mode decomposition (EEMD), principal component analysis (PCA), independent component analysis (ICA) and S-transform (ST) to study. Firstly, EEMD is used to decompose the single channel noise signal collected at the driver’s position into multiple intrinsic mode functions (IMF); Secondly, PCA is used to reduce the dimension of IMFs to remove the redundant IMF; Next, ICA processing is performed on the remaining IMFs to obtain independent IC components; Finally, S-transform is used to analyze the time-frequency of IC component, and the source of IC component is identified by prior experience. The results show that the main noise sources are the vibration radiation noise of related parts in the cab, the combustion noise of diesel engine and the fan noise. After identifying the main noise sources, the next step is to study the contribution of these noise sources, which provides a new idea for noise control.