Engine Misfire Fault Detection Based on the Channel Attention Convolutional Model

To accurately diagnosemisfire faults in automotive engines,we propose a Channel Attention Convolutional Model,specifically the Squeeze-and-Excitation Networks(SENET),for classifying engine vibration signals and precisely pinpointing misfire faults.In the experiment,we established a total of 11 distinct states,encompassing the engine’s normal state,single-cylinder misfire faults,and dual-cylinder misfire faults for different cylinders.Data collection was facilitated by a highly sensitive acceleration signal collector with a high sampling rate of 20,840Hz.The collected data were methodically divided into training and testing sets based on different experimental groups to ensure generalization and prevent overlap between the two sets.The results revealed that,with a vibration acceleration sequence of 1000 time steps(approximately 50 ms)as input,the SENET model achieved a misfire fault detection accuracy of 99.8%.For comparison,we also trained and tested several commonly used models,including Long Short-Term Memory(LSTM),Transformer,and Multi-Scale Residual Networks(MSRESNET),yielding accuracy rates of 84%,79%,and 95%,respectively.This underscores the superior accuracy of the SENET model in detecting engine misfire faults compared to other models.Furthermore,the F1 scores for each type of recognition in the SENET model surpassed 0.98,outperforming the baseline models.Our analysis indicated that the misclassified samples in the LSTM and Transformer models’predictions were primarily due to intra-class misidentifications between single-cylinder and dual-cylinder misfire scenarios.To delve deeper,we conducted a visual analysis of the features extracted by the LSTM and SENET models using T-distributed Stochastic Neighbor Embedding(T-SNE)technology.The findings revealed that,in the LSTMmodel,data points of the same type tended to cluster together with significant overlap.Conversely,in the SENET model,data points of various types were more widely and evenly dispersed,demonstrating its effectiveness in distinguishing between different fault types.

SEFormer:A Lightweight CNN-Transformer Based on Separable Multiscale Depthwise Convolution and Efficient Self-Attention for Rotating Machinery Fault Diagnosis

Traditional data-driven fault diagnosis methods depend on expert experience to manually extract effective fault features of signals,which has certain limitations.Conversely,deep learning techniques have gained prominence as a central focus of research in the field of fault diagnosis by strong fault feature extraction ability and end-to-end fault diagnosis efficiency.Recently,utilizing the respective advantages of convolution neural network(CNN)and Transformer in local and global feature extraction,research on cooperating the two have demonstrated promise in the field of fault diagnosis.However,the cross-channel convolution mechanism in CNN and the self-attention calculations in Transformer contribute to excessive complexity in the cooperative model.This complexity results in high computational costs and limited industrial applicability.To tackle the above challenges,this paper proposes a lightweight CNN-Transformer named as SEFormer for rotating machinery fault diagnosis.First,a separable multiscale depthwise convolution block is designed to extract and integrate multiscale feature information from different channel dimensions of vibration signals.Then,an efficient self-attention block is developed to capture critical fine-grained features of the signal from a global perspective.Finally,experimental results on the planetary gearbox dataset and themotor roller bearing dataset prove that the proposed framework can balance the advantages of robustness,generalization and lightweight compared to recent state-of-the-art fault diagnosis models based on CNN and Transformer.This study presents a feasible strategy for developing a lightweight rotating machinery fault diagnosis framework aimed at economical deployment.

A Latency-Aware and Fault-Tolerant Framework for Resource Scheduling and Data Management in Fog-Enabled Smart City Transportation Systems

Thedeployment of the Internet of Things(IoT)with smart sensors has facilitated the emergence of fog computing as an important technology for delivering services to smart environments such as campuses,smart cities,and smart transportation systems.Fog computing tackles a range of challenges,including processing,storage,bandwidth,latency,and reliability,by locally distributing secure information through end nodes.Consisting of endpoints,fog nodes,and back-end cloud infrastructure,it provides advanced capabilities beyond traditional cloud computing.In smart environments,particularly within smart city transportation systems,the abundance of devices and nodes poses significant challenges related to power consumption and system reliability.To address the challenges of latency,energy consumption,and fault tolerance in these environments,this paper proposes a latency-aware,faulttolerant framework for resource scheduling and data management,referred to as the FORD framework,for smart cities in fog environments.This framework is designed to meet the demands of time-sensitive applications,such as those in smart transportation systems.The FORD framework incorporates latency-aware resource scheduling to optimize task execution in smart city environments,leveraging resources from both fog and cloud environments.Through simulation-based executions,tasks are allocated to the nearest available nodes with minimum latency.In the event of execution failure,a fault-tolerantmechanism is employed to ensure the successful completion of tasks.Upon successful execution,data is efficiently stored in the cloud data center,ensuring data integrity and reliability within the smart city ecosystem.

Integrated Equipment with Functions of Current Flow Control and Fault Isolation for Multiterminal DC Grids

The multi-terminal direct current(DC)grid has extinctive superiorities over the traditional alternating current system in integrating large-scale renewable energy.Both the DC circuit breaker(DCCB)and the current flow controller(CFC)are demanded to ensure the multiterminal DC grid to operates reliably and flexibly.However,since the CFC and the DCCB are all based on fully controlled semiconductor switches(e.g.,insulated gate bipolar transistor,integrated gate commutated thyristor,etc.),their separation configuration in the multiterminal DC grid will lead to unaffordable implementation costs and conduction power losses.To solve these problems,integrated equipment with both current flow control and fault isolation abilities is proposed,which shares the expensive and duplicated components of CFCs and DCCBs among adjacent lines.In addition,the complicated coordination control of CFCs and DCCBs can be avoided by adopting the integrated equipment in themultiterminal DC grid.In order to examine the current flow control and fault isolation abilities of the integrated equipment,the simulation model of a specific meshed four-terminal DC grid is constructed in the PSCAD/EMTDC software.Finally,the comparison between the integrated equipment and the separate solution is presented a specific result or conclusion needs to be added to the abstract.

ELECTRO-THERMAL EFFECTS AND DEFORMATION RESPONSE OF CARBON FIBER MAT CEMENT BEAMS

A carbon fiber mat is a sheet composed of intercrossing short carbon fibers,which has more stable and lower electrical resistivity compared with dispersed short carbon fiber mixed in cement.Thereby carbon fiber mat cement could exhibit obvious electro-thermal effect.When electrified,the temperature of composite structures made up of cement mortar and carbon fiber mat will rise rapidly.If the temperature field is not uniform,temperature difference will cause structures to deform,which can be used to adjust the deformation of structures.The temperature field and deformation response driven by the electro-thermal effects of a type of carbon fiber mat cement beams are studied.Firstly,the temperature and deformation responses are studied using theories of thermal conduction and elasticity.Secondly,experimental results are given to verify the theoretical solution.These two parts lay the foundation for temperature and deformation adjustment.

Model of Polysilicon Electro-thermal Micro Actuator and Research of Micro Scale Effect

A type of crank beam electro-thermal micro actuator was prescribed. Mechanical model of the actuator was established, and the static characteristic was analyzed.Comparing the theoretical analysis with experimental data, it is found that the thermodynamic character of material in micro actuator has a different variable regularity contrasted to that used in macro scale machines. It is the micro scale effect that results in the deviation between the simulating result and experimental results. The thermodynamic expression of polysilicon, which was fitted by means of the experimental data concerned, was used to modify the mechanical model. The modified model, in which the micro scale thermodynamic characteristic was considered, was more reasonable and could make the optimal design and control strategies analyzing the straight-line micro actuator more feasible.

Microstructure and wear resistance of electro-thermal explosion sprayed stellite coating used for remanufacturing

Electro-thermal explosion directional spraying was used to prepare the stellite coating on substrate of the AISI 1045 steel. The morphologies of cross-section and worn scar, porosity, distribution of elements, micro- hardness and wear resistance of the coating were determined by means of SEM, EDAX, micro-hardness tester and sliding wear tester. Because of the compact construction, good bonding and high hardness, the coating is characterized by good wear resistance. The results show that the mainly failure mode of the stellite coating is micro- plowing.

STUDY ON THE THERAPEUTIC EFFECT AND MECHANISMS OF ELECTRO-THERMAL NEEDLING FOR TREATMENT OF VULVAL LEUKOPLASIA

In the present paper,444 patients with vulvar leukoplasia were treated by selectingacupoints in the local area and along the meridian plus Qugu（CV 2）and Huiyin（CV 1）and usingelectro-thermal needling.The total effective rate was up to 100.0％and the cure rate 87.3％.Theelectro-thermal effect directly acted on the affected area but strengthened the immunologic function ofthe whole body and raised the content of serum copper.

ELECTRO-THERMAL MOXIBUSTION ON ACUPOINTS FOR TREATMENT OF 98 CASES OF SCIATICA

98 patients with sciatica are treated.by stimubting acupoints using a self-made electro-thermal moxibustion instrument.Results show that 82 cases arecured,8 improved and 5 effective,with the total effective rate of 96.9％.The temperature relesed from this instrument is adjustable.The electro-thermal moxibustion therapy is short in treatment duration and rapid in taking effect.Ithas no needling-induced pain and no side-effects,and is accepted preferably by patients.

基于AHRFaultSegNet深度学习网络的地震数据断层自动识别

断层识别是地震数据解释的重要环节之一。深度学习技术的发展有效提高了断层自动识别的效率和准确性。然而,目前在断层的自动识别任务中,如何准确捕捉断层细微结构并有效抵抗噪声干扰仍然是一个具有挑战性的问题。为此,在HRNet网络的基础上,构建了一种基于解耦自注意力机制的高分辨率断层识别网络模型AHRFaultSegNet。对于自注意力机制解耦,结合空间注意力和通道注意力,代替HRNet中并行传播的卷积层,在减少传统自注意力机制计算量的同时,模型可以在全局范围内计算输入特征的相关性,更准确地建模非局部特征;对解耦自注意力使用残差连接来保留原始特征,在加速模型训练的同时,使模型能够更好地保持细节信息。实验结果表明,所提出的网络模型在Dice、Fmeasure、IoU、Precision、Recall等性能评价指标上均优于其他常见的断层自动识别网络模型。通过对合成地震数据与实际地震数据等进行测试,证明了该方法对断层细微结构具有良好的识别效果并且具有良好的抗噪能力。

High-temperature corrosion-resistance performance of electro-thermal explosion spraying coating

As a new spraying technology used in the remanufacturing engineering, electro-thermal explosion spraying holds a lot of advantages. Electro-thermal explosion spraying coating aliquation phenomena are reduced and non-crystal, micro-crystal and millimicron-crystal and other microstructure are formed. The corrosion-resistance ability of electro-thermal explosion spraying coating in high temperature environment was surveyed respectively. SEM equipped with EDS was employed to analyze the microstructure of spraying coating before and after corrosion. The corrosion-resistance mechanism of the spraying coating was discussed.

Gouge stability controlled by temperature elevation and obsidian addition in basaltic faults and implications for moonquakes

Basalt is a major component of the earth and moon crust.Mineral composition and temperature influence frictional instability and thus the potential for seismicity on basaltic faults.We performed velocitystepping shear experiments on basalt gouges at a confining pressure of 100 MPa,temperatures in the range of 100-400℃ and with varied obsidian mass fractions of 0-100%under wet/dry conditions to investigate the frictional strength and stability of basaltic faults.We observe a transition from velocity-neutral to velocity-weakening behaviors with increasing obsidian content.The frictional stability response of the mixed obsidian/basalt gouges is characterized by a transition from velocitystrengthening to velocity-weakening at 200℃ and another transition to velocity-strengthening at temperatures>300℃.Conversely,frictional strengths of the obsidian-bearing gouges are insensitive to temperature and wet/dry conditions.These results suggest that obsidian content dominates the potential seismic response of basaltic faults with the effect of temperature controlling the range of seismogenic depths.Thus,shallow moonquakes tend to occur in the lower lunar crust due to the corresponding anticipated higher glass content and a projected temperature range conducive to velocity-weakening behavior.These observations contribute to a better understanding of the nucleation mechanism of shallow seismicity in basaltic faults.

Characterization and spatial analysis of coseismic landslides triggered by the Luding Ms 6.8 earthquake in the Xianshuihe fault zone, Southwest China

On September 5, 2022, a magnitude Ms 6.8 earthquake occurred along the Moxi fault in the southern part of the Xianshuihe fault zone located in the southeastern margin of the Tibetan Plateau,resulting in severe damage and substantial economic loss. In this study, we established a coseismic landslide database triggered by Luding Ms 6.8 earthquake, which includes 4794 landslides with a total area of 46.79 km^(2). The coseismic landslides primarily consisted of medium and small-sized landslides, characterized by shallow surface sliding. Some exhibited characteristics of high-position initiation resulted in the obstruction or partial obstruction of rivers, leading to the formation of dammed lakes. Our research found that the coseismic landslides were predominantly observed on slopes ranging from 30° to 50°, occurring at between 1000 m and 2500 m, with slope aspects varying from 90° to 180°. Landslides were also highly developed in granitic bodies that had experienced structural fracturing and strong-tomoderate weathering. Coseismic landslides concentrated within a 6 km range on both sides of the Xianshuihe and Daduhe fault zones. The area and number of coseismic landslides exhibited a negative correlation with the distance to fault lines, road networks, and river systems, as they were influenced by fault activity, road excavation, and river erosion. The coseismic landslides were mainly distributed in the southeastern region of the epicenter, exhibiting relatively concentrated patterns within the IX-degree zones such as Moxi Town, Wandong River basin, Detuo Town to Wanggangping Township. Our research findings provide important data on the coseismic landslides triggered by the Luding Ms 6.8 earthquake and reveal the spatial distribution patterns of these landslides. These findings can serve as important references for risk mitigation, reconstruction planning, and regional earthquake disaster research in the earthquake-affected area.

Dynamic Vision Enabled Contactless Cross-Domain Machine Fault Diagnosis With Neuromorphic Computing

Dear Editor,This letter presents a novel dynamic vision enabled contactless cross-domain fault diagnosis method with neuromorphic computing.The event-based camera is adopted to capture the machine vibration states in the perspective of vision.

Design and Fabrication of 2-DOF Micromirror Array Based on Electro-Thermal Actuators

With surface- and bulk-micromachining, an 8 × 8 mirrors array is designed, fabricated and tested, which is based on electro-thermal actuators and can be addressed individually. The micromirror is square shaped, 4-corner-actuated. Its dimension is 200 μm × 200 μm. The substrate below it is caved away to ensure a tilt at an angle as large as possible. To protect the etch-sensitive features on the front side of the wafer undamaged during wet deep silicon etch on the backside, the wax protective coating process is used. Mirror actuated by powering an alternative pair of heaters will tilt in 2-DOF. If its 4 cantilevers/heaters are powered synchronously, it will move in a piston mode. The effective arrays are more than 80% out of the three finished wafers. When the ramp voltage frequency applied to a pair of neighboring cantilevers is 5 Hz at 10 V, the average tilting angle can be ± 8°.

Microstructure and Deposition Mechanism of C/SiCN Composites Prepared by Rapid Electro-thermal Pyrolysis CVD

Carbon fiber-reinforced silicon carbonitride ceramic matrix composites （C/SiCN） were prepared by rapid electro-thermal pyrolysis CVD using liquid polymer hexamethyldisilazane （HMDS, （CH3）3SiNHSi（CH3）3） as precursor. Microstructure morphology and production technique of C/SiCN composites were investigated. Scanning electron microscopy and transmission electron microscopy were respectively employed to characterize microstructures of the as-received C/SiCN composites samples. The high temperature pyrolysis of HMDS results in destruction of molecular chain, fracture of bonds, as well as liquid-gas-solid conversion from polymer to ceramic. Microstructures observation indicates that there is a high degree of coalescence between SiCN matrix and C fiber. The deposition model of liquid precursor electro-thermal pyrolysis CVD is different from that of gas precursor isothermal chemical vapor infiltration. Rapid liquid flow and slow gas diffusion are key factors for the difference of two methods. Preparation of rapid electro-thermal pyrolysis CVD consists of four steps including liquid polymer infiltration, polymer pyrolysis, rapid deposition of pyrolyzed substances and rapid densification, respectively.

Autonomous Recommendation of Fault Detection Algorithms for Spacecraft

Dear Editor, This letter deals with the problem of algorithm recommendation for online fault detection of spacecraft. By transforming the time series data into distributions and introducing a distribution-aware measure, a principal method is designed for quantifying the detectabilities of fault detection algorithms over special datasets.

The MW5.5 earthquake on August 6,2023,in Pingyuan,Shandong,China:A rupture on a buried fault

On August 6,2023,a magnitude MW5.5 earthquake struck Pingyuan County,Dezhou City,Shandong Province,China.This event was significant as no large earthquakes had been recorded in the region for over a century,and no active fault had been previously identified.This study collects 1309 P-wave arrival times and 866 S-wave arrival times from 74 seismic stations less than 200 km to the epicenter to constrain the spatial distribution of the mainshock and its 125 early aftershocks by the double difference earthquake relocation method,and selects 864 P-waveforms from 288 stations located within 800 km of the epicenter to constrain the focal mechanism solution of the mainshock through centroid moment tensor inversion.The relocation and the inversion indicate,the Pingyuan MW5.5 earthquake was caused by a rupture on a buried fault,likely an extensive segment of the Gaotang fault.This buried fault exhibited a dip of approximately 75°to the northwest,with a strike of 222°,similar to the Gaotang fault.The rupture initiated at the depth of 18.6 km and propagated upward and northeastward.However,the ground surface was not broken.The total duration of the rupture was~6.0 s,releasing the scalar moment of 2.5895×1017 N·m,equivalent to MW5.54.The moment rate reached the maximum only 1.4 seconds after the rupture initiation,and the 90%scalar moment was released in the first 4.6 s.In the first 1.4 seconds of the rupture process,the rupture velocity was estimated to be 2.6 km/s,slower than the local S-wave velocity.As the rupture neared its end,the rupture velocity decreased significantly.This study provides valuable insights into the seismic characteristics of the Pingyuan MW5.5 earthquake,shedding light on the previously unidentified buried fault responsible for the seismic activity in the region.Understanding the behavior of such faults is crucial for assessing seismic hazards and enhancing earthquake preparedness in the future.

THE FUZZY NUMERICAL VALUE SIMULATION OF NANOMETER ELECTRO-THERMAL IN HOT-WORKING

The fuzzy numerical value analysis method is adopted for the first time, which solves the problem of nanometer electro-thermal in filming process, The key technique is embodied by controlling the time distribution, temperature and press in the filming process. The concrete technique of filming is showed by establishing the fuzzy mumbership function of above three indexes, which improves the precision of the materials of nanometer electro-thermal in hot-working. At the same time, the principles of the fuzzy relationship mapping inversion （FRMI） is put forward, Therefore, the standardization and continuity can be met.

Study on Approach of Static Security Assessment Accounting for Electro-thermal Coupling

A static security assessment approach considering electro-thermal coupling of transmission lines is proposed in this paper. Combined with the dynamic thermal rating technology and energy forecasting, the approach can track both the electrical variables and transmission lines’ temperature varying trajectory under anticipated contingencies. Accordingly, it identifies the serious contingencies by transmission lines’ temperature violation rather than its power flow, in this case the time margin of temperature rising under each serious contingency can be provided to operators as warning information and some unnecessary security control can also be avoided. Finally, numerical simulations are carried out to testify the validity of the proposed approach.