bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Automotive Collision Avoidance Lower Position Controller Based on GA Optimization
Authors: Huang Yuhao , Ni Fuyin
Published: July 2024

To improve the control stability of the lower controller in the vehicle collision avoidance system, and solve the problem of traditional fuzzy PID not providing good dynamic performance under large parameter changes, a lower controller for vehicle collision avoidance based on genetic algorithm optimized fuzzy proportional-integral-derivative (PID) control was studied. The vehicle collision avoidance system collects real-time motion information of the preceding vehicle through millimeter-wave radar and calculates the safety distance. The safety distance model and upper controller of the system calculate the required acceleration of the vehicle. Afterwards, the expected acceleration of the vehicle is controlled by the lower controller of fuzzy PID. At the same time, the improved GA is used to adjust the PID parameters, solving the problem of poor robustness of the lower controller. A simulation platform was built to simulate the longitudinal vehicle collision avoidance control system jointly. The simulation results show that the lower controller designed based on this control algorithm has better stability and meets the collision avoidance requirements, providing an important basis for the development of vehicle control systems.
Experimental Study and Influencing Factors Analysis of the Electric Gear Urea Pump Supply Performance
Authors: Tian Bingqi , Sun Lijing , Mao Liwei
Published: July 2024

An experimental study on four electric gear urea pumps was carried out, and the variation rules of supply flow rate, speed, and volumetric efficiency of the urea pumps were obtained. Test results show that the volumetric efficiency will be affected by the coupling of multiple factors simultaneously, showing complex nonlinearity. A simulation model whose accuracy was verified by test data was established for analyzing the influencing factors of supply performance. With the increase in speed, the variation of volumetric efficiency has a linear relationship with the change of radial clearance and a quadratic parabola relationship with the change of axial clearance. In the range of working speed, the influence of radial clearance on volumetric efficiency is more significant, while the influence of axial clearance on volumetric efficiency will be gradually enhanced with increasing speed. The radial tolerance range should be as small as possible to ensure the consistency of the urea pump’s volumetric efficiency.
Youla Parameterized Adaptive Hybrid Control for Active Vibration Control Platform
Authors: Yang Cong , Liu Tianqi , Li Feng , Wu Zhizheng
Published: July 2024

To increase the vibration attenuation of the damped platforms, an adaptive hybrid vibration control algorithm based on Youla (Q) parameterization is proposed, where the vehicle suspension platform is considered as an application example. First, an inner controller is designed to keep the hybrid control system stable. Then, the controller is extended to the Youla parameterized controller set. Finally, the Q-parameters are adjusted online by using a recursive least squares (RLS) adaptive algorithm to eliminate vibration disturbances. Simulation results demonstrate that the hybrid algorithm is capable of effectively suppressing the vibration signals.
Research on cooperative control of vehicle path tracking and lateral stability
Authors: Chen Luran , Liu Zhikun , Yin Dejun
Published: July 2024

This study presents a novel trajectory tracking control approach integrating steering angle and wheel torque output. Unlike conventional hierarchical methods, it considers front wheel steering angle and direct swing torque control simultaneously. Utilizing Model Predictive Control for autonomous vehicles, the system employs path tracking deviation as the state variable, front wheel steering angle, and overall additional yaw moment as control inputs. The coordinated control strategy enhances vehicle stability and contributes to heading angle changes, improving trajectory tracking accuracy. Simulation results in Matlab/Simulink demonstrate the validity and superiority of the proposed method in trajectory tracking and vehicle stability.
Reliability analysis of aerospace planetary roller screw mechanism considering multiple failure modes
Authors: Zhang Ming , Fan Yuanxun , Zhang Changhui , Song Hongzhou
Published: July 2024

Faults in planetary roller screw mechanisms under typical aerospace operating conditions are usually caused by the combined effects of multiple coupled failure modes. Reliability analysis methods that ignore correlation often lead to significant errors. In this paper, the failure models of the planetary roller screw mechanism under fatigue elastic failure, wear failure, and fracture failure are analyzed based on the stress-strength interference model, and failure functional functions are provided. The improved O. Ditlevsen second-order reliability bound theory is used to characterize the relationships between multiple failure modes. Using this method, reliability analysis and calculation of planetary roller screw pairs considering multiple failure modes have been performed, verifying the rationality and effectiveness of this method.
Study on Hot Weather Operation Flight Test of Civil Aircraft Fuel System
Authors: Zhao Shiyang , Ji Kelin
Published: July 2024

As one of the important on-board systems of an airplane, the fuel system of a civil aircraft mainly supplies fuel to the engine and APU of the aircraft, and it is necessary to ensure that the pressure and flow rate of the fuel supply meets the needs of the engine and APU under each kind of probable operating conditions. This paper studies the specific requirements of the airworthiness regulations for the fuel system to work under hot climate conditions. At the same time, it explores how to show the compliance of the fuel system with the airworthiness regulations through the flight test method, which covers the determination of the flight test parameters, the control of the hot fuel temperature, the test modification, the implementation of the flight test mission and the analysis of the results. This paper provides a reference for the implementation of the hot weather operation of similar types of aircraft fuel systems.
Loss model of low pressure compressor for mechanical vapor recompression system
Authors: Le Wang , Pengtao Huang , Jun Xiao , Maofei Geng
Published: July 2024

Low pressure compressor (LPC) serves the role of enhancing pressure levels of secondary steam at nominal pressure ratios (1.5), procured from the evaporator as a primary thermal energy source. A loss model has been proficiently proposed to rapidly predict the performance of the LPC. Instead of conventional lump sum loss equations, the model adopts well-established one-dimensional (1D) loss formulations scattered across scholarly publications. Given an explicit configuration of the LPC, the environmental conditions, rotational velocity, and capacity, static and total temperatures, static and total pressures, pressure reductions, polytropic head, and efficiencies of each individual segment of the compressor can be calculated. Validation of this model was done using computational fluid dynamics (CFD) analysis. This model renders it feasible to conduct a parametric examination of the impact of each loss apparatus on the LPC’s capability, thereby aiding designers in substantiating design choices that minimize these losses and consequently positively influencing the comprehensive efficiency.
Circuit Breaker Fault Diagnosis Method Based on Integrated OCSSA-VMD-CNN-BiLSTM Method
Authors: Liu Wanli , Xu Mingshen , Zhang Jingzhong , Guo Haoxuan , Kang Di , Dou Longjiang
Published: July 2024

The paper proposes a novel approach to diagnose circuit breaker faults by integrating OCSSA, VMD, CNN, and BiLSTM algorithms. Firstly, OCSSA optimizes the parameters of VMD to reduce noise interference. Then, VMD decomposes the circuit breaker operating signals into characteristic signals. Secondly, CNN captures mechanical fault characteristics from the decomposed signals. Finally, BiLSTM applies CNN’s results for feature classification. Experimental results show that combining improved VMD with the CNN-BiLSTM model achieves a fault classification accuracy rate of 99.5%, surpassing other traditional models such as VMD-CNN-BiLSTM and ELMD in accuracy and robustness.
Simulation Study on Defect Damage Behavior of Fe under Irradiation Environment
Authors: Liu Chengwei , Yin Jian , Liu Zekun , Huang Xinming , Wei Shaochong , Zhang Wenli , Wei Pengyu , Zou Yang , Chen Guoxing
Published: July 2024

As a commonly used structural material in nuclear power plants, Reactor pressure vessel (RPV) steel is subjected to high-energy neutron irradiation from the reactor core for a long time, and the service environment is harsh. The accumulation of point defects (interstitial atoms and vacancies) generated by irradiation over a long period can seriously affect the microstructure of the material. The macroscopic properties of the material changed until the material failed, which threatened the safety and operation stability of nuclear power plants. This paper used the method of molecular dynamics to simulate the cascade collision process of Fe in the irradiation environment. The relationship between different factors and radiation damage defects was studied. Firstly, the quantity of the Frenkel pairs increases rapidly in the irradiation environment, and then recombination occurs after reaching the peak, which makes the quantity of the Frenkel pairs decrease rapidly. Finally, the quantity of Frenkel pairs is in a stable trend. When PKA energy and temperature increase, the higher the quantity of Frenkel pairs at the peak is, the higher the recombination rate of defects is. Meanwhile, the larger the cluster size of interstitial atoms and vacancies is, the greater the corresponding quantity of clusters is. As PKA energy increases, the quantity of residual Frenkel pairs at stability increases, while the number of residual Frenkel pairs at stability decreases with temperature. This is attributed to the intense thermal motion of molecules at high temperatures, resulting in the quantity of Frenkel pairs decreasing at the stable stage. Therefore, by simulating the irradiation damage process of Fe, the prediction of material irradiation damage under a neutron irradiation environment is provided, and the service life of materials can be provided with theoretical guidance.
Construction and Experimental Research of Active Vibration Control System of Voice Coil Motor with Integral Acceleration Feedback
Authors: Pu Huayan , Xiong Jing , Wang Min
Published: July 2024

The skyhook control technology is widely used in active vibration isolation and has proven effective. However, the absolute speed sensor used in the skyhook control technology is easily affected by external factors and may be easily damaged. There are few application scenarios for the skyhook control technology. To overcome this limitation, a brand-new approach is proposed for the design of an isolator that involves a voice coil motor (VCM) and an accelerometer. First of all, the proposed structure is introduced, and the dynamic model is established to achieve an analytical solution. Then, an integral acceleration feedback (IAF) algorithm is introduced and simulations are carried out. Finally, a prototype is constructed to verify its vibration isolation performance. From the experimental results, it can be concluded that the proposed active vibration control system (AVCS) can effectively reduce the peak value near the natural frequency, with a peak value reduction of 14.77 dB. Compared with the simulation results, the peak change rate at 12.5 Hz is 3.92%. AVCS with IAF can be applied to more application scenarios with a similar isolation effect to skyhook control technology.
Capacity assessment of railway axle journal bearing addressing a localized rolling contact fatigue failure mechanism
Authors: Xin Min , Bian Zhi-Hong , Zhao Yong-Xiang
Published: July 2024

A framework for assessing the capacity of railway axle journal bearings is presented after elaborating on the locale rolling contact fatigue (RCF) failure mechanism. Three phases are conducted, including the determination of bearing service loads, finite element analysis (FEA) on the localized RCF stresses of bearing components, and the life-related capacity assessment on the bearings and bearing components. Results prove that wheel-track (WT) contact forces inspected by an instrumented wheel set can be transferred into bearing service loads. Two-step FEA from the global wheel set to the local bearings is used to obtain localized RCF stresses at dangerous locations around the bearing contact regions. After determining the locations, a life-related capacity assessment is performed by evaluating equivalent RCF stresses and lives at the locations to determine the weakest bearing component. Typical practice is given in agreement with FEA. This method deals with the FEA of bearing structures, material cyclic stress-strain curves, and probabilistic RCF life curves. Therefore, this work greatly enhances the development of rail-bearing materials, innovative structures, and capacity assessment.
Study on primary frequency modulation control strategy based on wind-fire cooperation
Authors: Li Kai
Published: July 2024

Due to the increasing proportion of wind power in the power system, the wind turbine should have the ability of primary frequency modulation when integrated into the power system. At the wind turbine level, different methods are adopted according to different wind speeds, which can get the wind turbine fully joined in the system. Secondly, this paper gives full consideration to the characteristics of thermal and wind power units and proposes a joint primary frequency modulation method between the thermal and wind farms. The output of wind and thermal power is determined by adding a frequency divider. The system stability and reaction speed are effectively enhanced.
Design and Simulation Analysis of Antenna Structure for Active Phased Array Radar
Authors: Cai Sen , Yang Zhen , Li Jingxiao , Lu Dongdong , Shi Tongwu
Published: July 2024

This article adopts a modular design concept to design an active phased array radar antenna system structure and elaborates on its structural layout design and thermal design content. A finite element model of the antenna structure framework was established, and the rationality of its structural and thermal design was verified through static and thermal simulation analysis.
Simulation and Experimental Correction of Thermal Errors in Electric Spindles
Authors: Zhang Yu , Zhang Qiangang
Published: July 2024

The heat generated by the spindle leads to thermal deformation, which can seriously affect machining accuracy. ANSYS software is used to establish the heat-fluid-solid coupling simulation model of the electric spindle. Temperature rise and thermal error experiments of the electric spindle are carried out. We modified the theoretical and empirical values used in the simulation according to the experimental data. Experimentally, it is demonstrated that the precision of the simulation increased by 27% after modification.
Identification Method of Transmission Line Parameters Considering Impact of Electro Thermal Coupling Effect
Authors: Wu Yifan , Dong Xiaoming , Yu Shunxiang , Fan Jingdong
Published: July 2024

Studies for high voltage power networks generally ignore line resistance with the assumption of being far less than line reactance. However, this treatment could cause certain errors in analysing low-voltage distributed networks, causing the assumption to no longer be applicable. Such errors could be significant considering the impact of load carrying and ambient conditions, such as online resistance or temperature due to electro-thermal coupling (ETC). Then, it becomes an open question to accurately capture the system state of distribution networks due to changed line parameters. Integrating new style energy sources, such as renewable power generation, energy storage applications, and adjustable power load, will promote the deployment of measurement devices at distribution networks. With the assumption of sufficient accumulated data offered by online monitoring terminals, this study proposes a nonlinear regression method—Levenberg-Marquardt—to identify the parameters of the line. However, since it is difficult to access practical data, this study employs the electro-thermal coupling power flow (ETCPF) to simulate line operation and take the results as monitoring data for case studies. The identification results under various data volumes and error levels demonstrate the reliability and accuracy of the proposed approach.
Adaptability Analysis of Differential Protection for Output Transformers in Wind Power Plants
Authors: Yang Xuemei , Li Hanjiang , Ni Yingqian , Deng Bowen , Ren Tingting
Published: July 2024

After large-scale integration of wind farms into the power grid, according to the requirements of the State Grid’s wind power grid connection operation guidelines, wind farms should have low-voltage ride-through capability. The short-circuit current of wind farms will have a significant impact on the identification of excitation inrush currents in the transformers sent out by the wind farms, and the saturation of current transformers will also have an impact on differential protection. Analysis shows that after the wind power is connected, the harmonic components contained in the fault current output by the wind farm will cause the second harmonic braking component to malfunction, and there is a risk of transformer differential protection rejecting operation. At the same time, it will make the current transformer more susceptible to saturation, and the saturation of TA will increase the differential current of the transformer, which may cause misoperation of the transformer differential protection.
Multi-Objective Optimization Design of 40 MW High-Temperature Superconducting Motor
Authors: Jia Shiqi , Zhang Dong , Wang Lei , Zhang Jiancheng , Zhang Guomin
Published: July 2024

To reduce the length of the superconducting wire of the superconducting motor, the no-load back EMF E and the magnetic field component perpendicular to the wire B⊥ were selected as the optimization goals. Therefore, a multi-objective optimization method based on the Response Surface Method (RSM) and Genetic Algorithm (GA) was proposed by taking a high-temperature superconducting motor (HTSM) with a rated power of 40 MW as the research object. Firstly, the overall structure, mathematical model, and output characteristics of HTSM were introduced. Secondly, the sample points required for constructing the RSM equation were obtained by Finite Element Analysis (FEA), and the multi-objective optimization of the RSM equations was performed by applying GA to obtain the Pareto optimal frontier. Finally, the calculated optimal design was simulated and verified. Compared with the initial design, the E of the optimized HTSM was increased by 4.47%, and the B⊥ was reduced by 4.83%. Based on the motor parameters obtained by multi-objective optimization, the final optimized design of HTSM was obtained. The length of the superconducting wire used in the motor has been reduced by 10.2%, which greatly reduces the cost.
Model-free three-vector predictive current control of permanent magnet synchronous motor based on improved sliding mode observer
Authors: Huang Nan , Zhang Yufeng , Tian Beibei
Published: July 2024

To address the complexity of vector selection in the conventional predictive current control strategy and the reduction of control system robustness when the motor parameters change, this paper proposes a finite-set model-free three-vector predictive current control method for permanent magnet synchronous motor based on the improved sliding-mode perturbation observer. According to the mathematical model of a permanent magnet synchronous motor under perturbation, a new hyperlocal model is established, and the conventional vector traversal optimization method is optimized to obtain the necessary basic voltage vector by analyzing the function with one judgment. Meanwhile, the sliding mode perturbation observer is designed using the fast exponential convergence law to observe the unknown part. Finally, by experimentally contrasting the proposed technique with the conventional three-vector model predictive current control, the method suggested in this paper can successfully reduce the current pulsation and inhibit the system perturbation caused by the parameter change, ensuring the steady state performance of the motor, as demonstrated by the experimental comparison with the conventional three-vector model predictive current control method.
Influence Law of Electromagnetic Induction Heating Parameters on the Leveling Effect in Thin Plates
Authors: Wang Yefan , Li Shengrong , He Zixi
Published: July 2024

In order to analyze the influence of electromagnetic induction heating parameters on the leveling effect of thin plates after welding, and summarize their influence rules, this paper first introduces the principle of induction heating, further reveals the mechanism of electromagnetic induction heating to control the deformation of thin plates, and discusses the parameters that affect the process of electromagnetic induction heating. Based on this, the electromagnetic induction heating under different gap distances, current intensity, and heating frequency is simulated by finite element simulation software. The experimental verification is carried out, which lays the foundation for selecting the appropriate electromagnetic induction heating-related parameters.
Analysis and Modeling Study on the Effect of Working Parameters of Portable Neutron Tubes on Target Current
Authors: Li Zhuoxi , Guo Wei , Chen Yiting , Xu Pengcheng , Liu Guocai
Published: July 2024

As an important parameter index of sealed neutron tubes, their high-pressure side target current directly affects neutron yield. The working parameters of a neutron tube affect the target current. Using self-developed neutron tubes, the influence of operating parameters of neutron tubes on target current was studied. The effect curves of gas pressure, anode high pressure, and target high pressure on neutron yield were obtained, and the secondary electron suppression characteristics of the target current were obtained. Further, we analyze and fit a multi-parameter coupling model for the target current, to provide a theoretical basis for establishing the working state and improving the performance of sealed neutron tubes.
Direct Writing Highly Conductive Silver Pattern on Flexible Substrate Based on Particle-Free and Ionic Liquid-Assisted Ink
Authors: Xie Xiaosheng , Wu Zijian , Pan Daocheng , Shi Xinan
Published: July 2024

Particle-free silver inks have the advantage of low sintering temperature, high stability, and easy synthesis over traditional nanoparticle-based silver inks, which have been widely applied in the printing electronic industry. In this paper, we develop a novel particle-free and ionic liquid-assisted silver ink consisting of silver acetate and formic acid/iso-propanolamine liquid that can be used to print highly conductive silver patterns at low sintering temperatures. A variety of continuous and consistent silver circuits with a resistivity of 7.7 µΩ·cm can be printed by a dispenser machine, which is only 4.8 times bulk silver. Furthermore, the low-resistivity silver patterns can be also printed on the flexible polyimide foil, which maintains the stability of resistivity and mechanical properties after bending multiple times, demonstrating that our ionic liquid-assisted silver ink can be applied in flexible electronic devices. Besides, our particle-free silver ink can be utilized to write electric circuits directly with a ball-point pen.
2 μm Low-noise Narrow-linewidth Single-frequency Fiber Laser Based on Self-injection Locking Technique
Authors: Gao Ruixiang , Fang Qiang , Xu Yang , Gao Song , Jiang Peiheng , Fu Shijie , Sheng Quan , Shi Wei
Published: July 2024

Based on the self-injection locking technique, we demonstrate a low-noise and narrow linewidth of 2 μm single-frequency distributed Bragg reflection fiber laser with an optical self-injection feedback loop (OSIFL). The OSIFL consists of a piece of delay fiber and two polarization-maintaining optical couplers, which can effectively narrow down the linewidth and suppress the relative intensity noise (RIN) of the laser. It was observed that the laser linewidth was narrowed down from the initial 6.5 kHz to 1.6 kHz while the laser relaxation oscillation peak was reduced from -100.3 dB/Hz to -113.5 dB/Hz. Experimental results demonstrate that by extending the photon lifetime we can effectively narrow down the linewidth and significantly reduce the RIN of the laser. This research is of great significance for promoting the development and application of 2 μm single-frequency lasers.
Ground Fault Routing Method for Flexible Grounding System Based on Transient Zero Sequence Current Comparison
Authors: Liu Cuicui , Wang Xiaoshuai , Xue Yongduan
Published: July 2024

As a new development direction of the domestic medium voltage distribution network, the flexible grounding method has a rapid expansion trend, and accordingly, the ground fault protection scheme needs to follow up quickly. This paper calculates and analyzes the distribution characteristics of transient electric quantities in the system under different fault conditions by establishing the transient equivalent model of shunt small resistor casting and cutting in the flexible grounding system. It is found that if transition resistance is small, the application of parallel small resistors will cause the transient zero sequence current amplitude of the faulty line to be maximum and have opposite polarity to the healthy line. When transition resistance is high, distribution characteristics of the transient zero sequence current projection component are also the same. Based on the above features, a flexible grounding system ground fault routing method is proposed, which can cope with a variety of ground fault situations in engineering practice with high reliability, and the correctness of the method is verified through simulation.
Analysis of Influence of Different Running Speeds on Lubrication Performance of Plain Bearings
Authors: Zhang Guangming , Shen Jifei , Zhu Hongxiu , Xiao Run
Published: July 2024

Given the influence of the running speed of rotating machinery on the lubrication performance of sliding bearings, based on the hydrodynamic lubrication theory, a numerical analysis model of hydrodynamic lubrication of rolling bearings is established and solved by the finite difference method. The lubrication characteristics of rolling bearings, such as oil film pressure, oil film temperature, oil film thickness, and temperature rise at different running speeds (10 r/min, 30 r/min, 120 r/min, 160 r/min), are obtained. The results show that the sliding bearing shows different trends at different rotational speeds, the maximum oil film temperature is 70.49℃, the film thickness ratio corresponding to the minimum oil film thickness is much more than 3, and the maximum oil film pressure and temperature rise meet the allowable requirements.
Simulation and Experimental Study of Mooring Function Composite Fragile Cover
Authors: Mao Yafei , Yu Jingui , Zhang Qiaoxin
Published: July 2024

Under the requirement that the fragile cover does not eject debris during missile launches, and to meet the demands of rapid combat, there is an urgent need for a lightweight missile launching system. Enhancing the effective utilization area of the fragile cover is an effective way to realize the lightweight of the missile launching system. This paper utilizes the properties of carbon fiber composite materials to design a novel frangible cover with mooring functionality and establishes numerical models for the cover’s pressure and bursting dynamics. In the pressure finite element model, the Tasi-Wu failure criterion is employed for damage assessment. In the bursting dynamics finite element model, a cohesive element is used to simulate the elastic behavior and damage evolution of the weak area, while a membrane element is employed to simulate the mooring function. Comparative analysis of numerical results with experimental data reveals minor discrepancies, with errors of 5.44% for maximum deformation under pressure and 8.1% for bursting force, respectively, validating the model’s rationality and effectiveness. Results from both experimental tests and finite element analyses demonstrate the successful implementation of mooring functionality in the segmented body. The effective utilization area of the cover was increased by 71.13%. This research provides a feasible direction for subsequent studies on non-ejecting frangible covers.
Evaluation Method of Generatrix Straightness Coefficient and Application in AZ31 Magnesium Alloy Panel
Authors: Li Yanjuan , Wang Zhongtang , Liu Quan
Published: July 2024

An evaluation method of the generatrix straightness coefficient for magnesium alloy panel is proposed. The generatrix straightness coefficient and characterization parameter are defined. The reasonable process parameters for equal curvature grid panels were determined, and various specifications of magnesium alloy grid panels were processed. For the magnesium alloy grid panel, with an increase in the curvature radius of the panel, the deviation of generatrix straightness and generatrix straightness coefficient of each point is reduced. The deviation of generatrix straightness at the junction of the transverse is the smallest. The deviation of generatrix straightness at the center of the grid is the maximum. The deviation of generatrix straightness at the junction of transverse and longitudinal ribs was minimal. The maximum deviation of generatrix straightness is 0.097 mm, and the maximum generatrix straightness coefficient is 0.277%.
Comprehensive Evaluation Study of Innovative Measurement Techniques in Surface Roughness within Manufacturing Processes
Authors: Guo Zizhou , Li Shuncai , Wang Xin
Published: July 2024

With the advancement of modern technology, numerous advanced methods for measuring surface roughness have emerged. These are categorized into contact and non-contact methods, such as optical, ultrasonic, and machine vision measurements. By researching and integrating various characteristics, including cutting parameters, vibration, and force signals, with workpiece texture images, a comprehensive model for predicting surface roughness is formed. These novel multidimensional feature prediction equations significantly enhance practicality and accuracy in assessing the surface quality of machined workpieces, marking a clear advancement over traditional measurement techniques.
Analysis of Novel Materials for Active Homogeneous Fields in High-field Nuclear Magnetic Resonance
Authors: Yan Ming , Wang Yaohui , Wang Heyang , Wu Pengfei
Published: July 2024

Nuclear magnetic resonance (NMR) spectroscopy, based on its extremely high backfield, can be used for the imaging and analysis of matter, which has given mankind a clearer perception of the composition of matter. The homogeneity of the magnet is the key to imaging. This paper analyzes the characteristics of various novel materials with active homogeneous fields regarding critical temperature, critical magnetic field, critical current and stress structure. The results show that YBCO and Bi-2223 strip structures cannot be wound when making coils, and with the change of rotation angle, the stronger the electromagnetic force on the strip, the greater the strain, which makes it difficult to fabricate uniform-field coils with high precision. In contrast, the feasibility of Bi-2212 in superconducting uniform-field coils is basically satisfied, and it has better performance.
An exactly solvable asymmetric K-exclusion process
Authors: Ayyer Arvind , Misra Samarth
Published: July 2024

We study an interacting particle process on a finite ring with L sites with at most K particles per site, in which particles hop to nearest neighbors with rates given in terms of t-deformed integers and asymmetry parameter q, where t > 0 and

q
⩾
0

are parameters. This model, which we call the (q, t) asymmetric simple K-exclusion process (ASEP), reduces to the usual ASEP on the ring when K = 1 and to a model studied by Schütz and Sandow (Phys. Rev. E, 1994) when

t
=
q
=
1

. This is a special case of the misanthrope process and as a consequence, the steady state does not depend on q and is of product form, generalizing the same phenomena for the ASEP. What is interesting here is the steady state weights are given by explicit formulas involving t-binomial coefficients, and are palindromic polynomials in t. Interestingly, although the (q, t) K-ASEP does not satisfy particle-hole symmetry, its steady state does. We analyze the density and calculate the most probable number of particles at a site in the steady state in various regimes of t. Lastly, we construct a two-dimensional exclusion process on a discrete cylinder with height K and circumference L which projects to the (q, t) K-ASEP and whose steady state distribution is also of product form. We believe this model will serve as an illustrative example in constructing two-dimensional analogues of misanthrope processes.

Simulations are attached as ancillary files.
Root patterns and exact surface energy of the spin-1 Heisenberg model with generic open boundaries
Authors: Dong Jiasheng , Lu Pengcheng , Cao Junpeng , Yang Wen-Li , Marquette Ian , Zhang Yao-Zhong
Published: July 2024

We investigate the thermodynamic limit and exact surface energy of the isotropic spin-1 Heisenberg chain with integrable generic open boundary conditions by a novel Bethe ansatz method. We obtain the homogeneous (or two-term) Bethe ansatz like equations for the zero roots of the transfer matrix. Based on the patterns of the zero roots, we analytical calculate the densities of zero roots and the surface energies of the model in all regimes of the boundary parameters.
Exploratory data analysis & EDS analysis on tool chip adhesion under dry and nano minimum quantity lubrication machining environment
Authors: Manohar R Gowri , R Rajaraman
Published: July 2024

Adhesion, abrasion, plowing and transverse displacement are the major causes of origin of friction. During dry machining of ductile materials, chips are fused with the rake face of the cutting tool and contribute to the formation of the built up edge. Built up edge protects the rake face of the tool from wear, but makes the machined surface rough. To improve the tribological properties and to decrease the tool-chip adhesion, cutting fluids are used. Cutting fluids are added to the machining zone to minimise cutting temperature and friction, but they result in environmental and health degradation. Surface texturing of tools is a potential way to modify the tribological properties of mating surfaces in order to increase the tribological qualities and decrease the tool-chip adhesion. The performance of surface textured tools depends upon orientation, dimple depth, width and pattern. Under lubrication regime, microholes in surface textured tools acts both as lubrication reservoir and traps wear debris to reduce abrasive wear. Nano Minimum Quantity Lubrication (nano-MQL) is an advanced lubrication technique used in machining processes, specifically designed to minimize the use of lubricants while maintaining effective lubrication. This method involves delivering an extremely small amount of high-performance lubricant directly to the cutting zone. The MoS2 lubricant with sunflower oil is typically in the form of nanodroplets, which are much smaller than conventional minimum quantity lubrication (MQL) droplets. The Exploratory Data Analysis (EDA) methodology enables the identification of patterns, trends, and outliers within the collected data, offering insights into the complex interplay of factors affecting the machining of Aluminium Alloy AA2024. At a spindle speed of 3500 rpm the feed force decreases by 37% under dry environment when compared with nano-MQL environment. Under dry environment average surface roughness reduces by 27% when compared with nano-MQL environment.
Conference travel on par with Africa’s per-capita carbon footprint
Authors: Allen Michael
Published: July 2024

Travel to more than 350 astronomy meetings in 2019 resulted in the emission of 42,500 tonnes of carbon dioxide.
IOP launches new inclusion programme
Authors: Banks Michael
Published: July 2024

The Institute of Physics (IOP) has launched a new award to help universities attract, support and retain a diverse physics community.
Recruiting and retaining good physics teachers
Authors: Follows Mike
Published: July 2024

A response to the careers article by Katherine Skipper (May 2024) about the upcoming “teacher degree apprenticeships” – a new route into teaching in which students will spend 40% of their time at university and the rest working in a school.
Missing pioneers
Authors: Swinbank Elizabeth
Published: July 2024

A response to Emma Chapman’s feature article on the development of radio astronomy (April 2024), which looked at how it grew from amateur roots to the professional discipline we know today.
The right stuff and the red stuff
Authors: Harris Margaret
Published: July 2024

Margaret Harris reviews Cosmonaut: a Cultural History by Cathleen S Lewis.
The weird and wonderful world of physics
Authors: Banks Michael
Published: July 2024

Featuring the noise produced by a school of fish, a quantum-inspired escape room and a new coffee lab, Michael Banks picks his favourite stories and quotes from the past month.
Lift-connected surface codes
Authors: Old Josias , Rispler Manuel , Müller Markus
Published: July 2024

We use the recently introduced lifted product to construct a family of quantum low density parity check codes (QLDPC codes). The codes we obtain can be viewed as stacks of surface codes that are interconnected, leading to the name lift-connected surface (LCS) codes. LCS codes offer a wide range of parameters—a particularly striking feature is that they show interesting properties that are favorable compared to the standard surface code. For example, already at moderate numbers of physical qubits in the order of tens, LCS codes of equal size have lower logical error rate or similarly, require fewer qubits for a fixed target logical error rate. We present and analyze the construction and provide numerical simulation results for the logical error rate under code capacity and phenomenological noise. These results show that LCS codes attain thresholds that are comparable to corresponding (non-connected) copies of surface codes, while the logical error rate can be orders of magnitude lower, even for representatives with the same parameters. This provides a code family showing the potential of modern product constructions at already small qubit numbers. Their amenability to 3D-local connectivity renders them particularly relevant for near-term implementations.
Pattern classification of bearing faults in PMSM based on time domain feature ensembles
Authors: G Geetha , P Geethanjali
Published: July 2024

This research aims to identify an effective feature-based pattern classification technique that uses vibration and current data to identify bearing conditions. The authors attempted non-conventional time-domain features to detect the bearing conditions in permanent magnet synchronous motors (PMSM). This work employs two case studies utilizing eight datasets from Paderborn University to identify the bearing conditions of three and twelve classes. In this work, support vector machine, k-nearest neighbor, random forest, decision tree, and naive Bayes classifiers with 10% holdout validation are applied to study 31 feature combinations. This study also examines the Henry gas solubility optimization technique for feature selection to identify the most discriminating features. The results indicate that four feature ensembles consisting of 2 to 5 features performed better with the support vector machine, k-nearest neighbor, and random forest classifiers. In contrast to previous relevant studies, the proposed features are useful in identifying PMSM-bearing conditions with the highest accuracy of 99.8% and 99% using current signals for 3 and 12 classes respectively for combined current operating conditions.
Transformer oil temperature sensing utilizing bundle plastic optical fiber sensor
Authors: Kadar Muhammad Sazlan Abdul , Ngajikin Nor Hafizah , Yaacob Maslina , Yasin Muhammad Zakir Md , Talib Mohd Aizam , Cholan Noran Azizan
Published: July 2024

A bundle plastic optical fiber (POF) that works based on an intensity modulation technique is experimentally demonstrated to sense the temperature of transformer oil. The sensor was developed using a bundle POF that is located perpendicular to an aluminum reflective film with an airgap cavity between these two elements. The simplicity of the architecture allows the development of an economical optical sensor system. To avoid interference effects by other substances in the oil, the sensor head is encapsulated with a metal protecting tube. The temperature measurement was realized in this study by monitoring the output light intensity in the visible light spectrum. For linearity range from 40 °C to 75 °C, the tested sensor exhibits a sensitivity of 0.0064 °C−1, a linearity coefficient of 0.95 and a resolution of 1.56 °C. These results demonstrate the suitability of the developed sensor for temperature oil monitoring in an electrical power transformer system.
Design, computational analysis and experimental study of a high amplification piezoelectric actuated microgripper
Authors: Das Tilok Kumar , Shirinzadeh Bijan
Published: July 2024

Increasing applications of compliant microgripper demands flexibility in working with a wide range of micro-objects which requires a large workspace, high precision motion, low parasitic motion, and satisfactory bandwidth control. To meet the requirement of pick and place manipulation tasks, a high amplification piezoelectric actuated microgripper is proposed and investigated in this paper. The high amplification of the microgripper is achieved using a compound amplifier. The compound amplifier is assisted to magnify the embedded piezoelectric actuator’s displacement. Two cascaded lever-type mechanisms are symmetrically connected with a bridge-type mechanism and form a three-stage amplification mechanism-based compound amplifier. Further, the four-bar parallelogram mechanisms are integrated with the third-stage displacement amplification mechanisms to linearize the output motion of the microgripper jaws. The characteristics of the microgripper were evaluated by computational analysis and validated using experimental investigations. Further, the design parameters are identified from the geometrical model of the individual displacement transmission mechanisms to perform a response surface optimization on the configured mechanism by the computational method. The design optimization of the microgripper resulted in a high displacement amplification ratio with a large workspace. The experimental investigations show that the designed microgripper is capable of achieving a high displacement amplification ratio of 34.5 and a total output displacement of 529.4 μm. Further, the characteristics of the microgripper such as motion resolution, and parasitic motion indicate that it will be able to perform high-precision micro-object grasping/releasing tasks.
Research on tool remaining useful life prediction algorithm based on machine learning
Authors: Ge Yong , Teo Hiu Hong , Moey Lip Kean , Tayier Walisijiang
Published: July 2024

Tool wear during machining significantly impacts workpiece quality and productivity, making continuous monitoring and accurate prediction essential. In this context, the present study develops an efficient tool wear prediction system to enhance production reliability and reduce tool costs. It is worth noting that conventional methods, including support vector regression, autoencoders, attention mechanisms, CNNs, and RNNs, have limitations in feature extraction and efficiency. Aiming at resolving these limitations, a multiscale convolutional neural network (MDCNN)-based algorithm is proposed for predicting the remaining life of milling cutters. The algorithm uses preprocessing techniques like wavelet transform and principal component analysis for noise reduction and feature extraction. It then extracts temporal data features using convolutional layers of different scales and employs a self-attention mechanism for feature encoding. Validation on the PHM2010 milling cutter wear dataset with 10-fold cross-validation demonstrates that the MDCNN model achieves a wear prediction accuracy of 97%, a recall rate of 98%, and an F1 score of 97%. The MDCNN model effectively processes multi-band data and captures complex temporal features, confirming its efficiency and accuracy in predicting milling cutter wear and remaining service life.
Why place matters
Authors: Furlong Jamie , Jennings Will
Published: July 2024

This final empirical chapter begins from the premise that there are places where demographic composition cannot fully account for the electoral performance of Labour or Conservatives. It explores, through qualitative case studies, two such areas where Labour (Merseyside) and Conservative (Lincolnshire) support are systematically under-predicted by statistical models. Using interviews with local political actors and experts and the iterative exploration and observation of constituencies within these two regions, we identify the place-based, contextual factors that help explain their unusual political characteristics. We argue that to understand the electoral geography of England and Wales, it is important to consider the role of local and regional (real or imagined) identities, culture, histories, economies, and party organization, which all, at least in the minds of local activists and observers, play a key role in shaping electoral competition. In short, place matters.
Equal Deeds, Different Needs
Authors: Bauer Alexander Max , Romann Jan
Published: July 2024

In a vignette study with a quota sample of the German population (n = 400), subjects had to redistribute a good between two hypothetical persons who contributed equally to the available amount but differed in quantity needed and the reason for their neediness. Within subjects, it was tested for the effects of need, accountability, and resource availability. Between subjects, kinds of needs were varied: Persons needed the good to survive, to live a decent life, to participate in society, or to be autonomous. Despite equal productivity, the mean share allocated to the needier person was significantly higher than an equal share. However, this share turned out significantly smaller when the needier person was accountable for needing more. Nonetheless, even if accountable, the needier person still got a share larger than their contribution. When there was a surplus of resources, the needier person got a higher share than when resources were scarce.
The Need for Measure Calibration in Experimental Philosophy
Authors: Cova Florian
Published: July 2024

Experimental philosophy purports to investigate folk intuitions about a wide array of topics. But can we be sure that the measures used by experimental philosophers succeed in capturing the intuitions they were intended to? Such questions about the content validity of measures in experimental philosophy have been at the heart of many methodological debates. In this chapter, my first goal is to argue that calibration methods—the fact of using measures on control cases in which we already know what participants’ answers should be if the measure is reliable—constitute a powerful, albeit underused, tool to make progress on such methodological debates. My second goal is then to show that calibration methods can also prove valuable when trying to improve existing measures. Thus, through three original studies, I show how calibration methods can be used to improve existing measures of participants’ intuitions about the objectivity of certain truths.