Roller Screw and Threaded Chain Speed Reducer: An Experimental Evaluation

We are developing a speed reducer that can be considered a transformation of a worm gear reducer: the worm is replaced by an inverted roller screw, and the gear is replaced by a threaded chain drive. This configuration lessens wear, increases load capacity, and improves efficiency. The threaded chain consists of nut-shaped links. This paper presents the results of tests carried out on a prototype with a reduction ratio of 46.

Analysis of secondary makeup characteristics of drill collar joint and prediction of downhole equivalent impact torque of Well SDTK1

Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.

Comprehensive Survey of the Landscape of Digital Twin Technologies and Their Diverse Applications

The concept of the digital twin,also known colloquially as the DT,is a fundamental principle within Industry 4.0 framework.In recent years,the concept of digital siblings has generated considerable academic and practical interest.However,academia and industry have used a variety of interpretations,and the scientific literature lacks a unified and consistent definition of this term.The purpose of this study is to systematically examine the definitional landscape of the digital twin concept as outlined in scholarly literature,beginning with its origins in the aerospace domain and extending to its contemporary interpretations in the manufacturing industry.Notably,this investigationwill focus on the research conducted on Industry 4.0 and smartmanufacturing,elucidating the diverse applications of digital twins in fields including aerospace,intelligentmanufacturing,intelligent transportation,and intelligent cities,among others.

基于嵌入式的通信电源控制器软件升级系统设计

研究了一种用于通信电源控制器的软件升级系统。系统基于GD32F405RG芯片开发,在APP阶段使用RS485通信总线作为信息传输方式接收升级程序,再利用CRC等校验算法验证信息传输的正确性,接着将升级程序存储到片外存储芯片W25Q128JVSQ并重启通信电源控制器;在BootLoader阶段将升级程序搬运到GD32F405RG的内部FLASH,同样验证通过后跳转运行。文中详细介绍了系统的总体设计和具体实现方法。测试结果表明,系统在15分钟内成功完成了对通信电源控制器的软件升级,升级后通信电源控制器正常运行。这种软件升级方法降低了升级通信电源维护过程的经济投入,提高了通信电源的可持续性和稳定性。

Nonlinear Analysis of Axial-load and Stress Distribution for Threaded Connection

Analytical method for the distributions of axial-load and stress is based on elastic assumption, but the threaded connections are often in plastic deformation stage in practice. Meanwhile the strain in the threaded connection is difficult to measure. So it is necessary to study the reliable numerical method. At present neither the convergence analysis of the computational results nor the elastic-plastic analysis in the loading-unloading process are studied. In this paper, von Mises plasticity and kinematic hardening model is used to describe the material response. A new convergence criterion for nonlinear finite element analysis of the loading-unloading process is proposed. An axisymmetric finite element model according to the proposed convergence criterion is developed and used to analyze the distributions of axial-load and stress. It can be conclude that the stress distribution analysis is more dependent on the mesh density than the axial-load distribution analysis. The stress distribution result indicates that with increasing of applied load, the engaged threads close to the nut-bearing surface become plastic firstly. The axial-load distribution result reveals that the load percentage carried by single thread depends on the position of thread and load intensity. When the load is relatively small, the applied load is mainly carried by the engaged threads near the nut-bearing surface, when the load is larger, the differences of percentages for all threads become small. The proposed convergence analyzing procedure is applicable for other nonlinear analyses. The obtained distributions of axial-load and stress can be a reference of engineering application.

Phase-field simulation of dendritic solidification using a full threaded tree with adaptive meshing

Simulation of the microstructure evolution during solidifi cation is greatly benefi cial to the control of solidifi cation microstructures. A phase-fi eld method based on the full threaded tree(FTT) for the simulation of casting solidifi cation microstructure was proposed in this paper, and the structure of the full threaded tree and the mesh refi nement method was discussed. During dendritic growth in solidifi cation, the mesh for simulation is adaptively refi ned at the liquid-solid interface, and coarsened in other areas. The numerical results of a threedimension dendrite growth indicate that the phase-fi eld method based on FTT is suitable for microstructure simulation. Most importantly, the FTT method can increase the spatial and temporal resolutions beyond the limits imposed by the available hardware compared with the conventional uniform mesh. At the simulation time of 0.03 s in this study, the computer memory used for computation is no more than 10 MB with the FTT method, while it is about 50 MB with the uniform mesh method. In addition, the proposed FTT method is more effi cient in computation time when compared with the uniform mesh method. It would take about 20 h for the uniform mesh method, while only 2 h for the FTT method for computation when the solidifi cation time is 0.17 s in this study.

Temperature field simulations during selective laser melting process based on fully threaded tree

Selective laser melting(SLM) is a promising technique for additive manufacturing. During SLM of metallic powder, the temperature field and thermal history are important to understand physical phenomena involved. The purpose of this study is to simulate the temperature field during the SLM process of a hollow cylinder shape part based on a fully threaded tree(FTT) technique, and to analyze the temperature variation with time in different regions of the part. A revised model for temperature field simulation in the SLM process was employed, which includes the transition of powder-to-dense sub-model and a moving volumetric Gaussian distribution heat source sub-model. The FTT technique is then adopted as an adaptive mesh strategy in the simulation. The simulation result shows that during the SLM process of cylinder part, the temperature of inner powder bed is obviously higher than external one. The temperature at the internal of the molten pool is also higher than external, which may lead to differences in microstructures and other properties between the two regions.

Object detection of artifact threaded hole based on Faster R-CNN

In order to improve the accuracy of threaded hole object detection,combining a dual camera vision system with the Hough transform circle detection,we propose an object detection method of artifact threaded hole based on Faster region-ased convolutional neural network(Faster R-CNN).First,a dual camera image acquisition system is established.One industrial camera placed at a high position is responsible for collecting the whole image of the workpiece,and the suspected screw hole position on the workpiece can be preliminarily selected by Hough transform detection algorithm.Then,the other industrial camera is responsible for collecting the local images of the suspected screw holes that have been detected by Hough transform one by one.After that,ResNet50-based Faster R-CNN object detection model is trained on the self-built screw hole data set.Finally,the local image of the threaded hole is input into the trained Faster R-CNN object detection model for further identification and location.The experimental results show that the proposed method can effectively avoid small object detection of threaded holes,and compared with the method that only uses Hough transform or Faster RCNN object detection alone,it has high recognition and positioning accuracy.

Growth of threaded AlN whiskers by a physical vapor transport method

Threaded aluminum nitride （A1N） whiskers are grown by a physical vapor transport method in a radio-frequency induction heating furnace. The resultant whiskers are characterized by X-ray diffraction, Raman scattering, scanning electron microscopy, transmission electron microscopy and photoluminescence. The analysis shows that the whiskers are single-crystalline, wurtzite AIN. The threaded A1N whiskers are 0.5 μm^100 μm in diameter and several millimeters in length in the fiber direction, and have lots of tiny sawteeth on the surface. The morphology of this threaded A1N whisker is beneficial for bonding when the whisker is used in composite. The growth of the whiskers is dominated by the vapor-solid （VS） mechanism, and the particular morphology might result from an oscillating condition produced in the radio-frequency induction heating furnace.

Sealing Reliability and Sensitivity Analysis for a Premium Threaded Connection Based on Kriging Model

In order to analyze the sealing performance of a new designed premium threaded connection,this paper studies the sealing reliability and sensitivity of the premium threaded connection at its most dangerous load condition based on Kriging model.The load condition of premium threaded connection in deep well is so complex that the most dangerous load point of premium threaded connection under the typical series loads is studied by finite element analysis(FEA) method firstly.Since the FEA of the premium threaded connection is too time-consuming,Kriging model which is accurate and efficient for multidimensional and highly nonlinear problems is built to calculate the sealing reliability of the premium threaded connection at the most dangerous load point.Finally,the sealing sensitivity analysis of the premium threaded connection is performed by the method of variance-based global sensitivity analysis.The work in this paper could contribute for the analysis and further improvement of the premium threaded connection.

Pull-out Behaviour of Axially Loaded Screwed-in Threaded Rods Embedded in CLT Elements: Experimental Study

Experimental investigation on the pull-out behaviour,including the withdrawal capacity,slip stiffness and inter-facial shear stress,of axially loaded screwed-in threaded rod embedded in cross laminated timber(CLT)was con-ducted.Specimens with varying embedment length and different number of threaded rods were tested in this study.To prevent premature splitting failure of timber,some specimens were reinforced in the direction perpen-dicular to the timber grain with self-tapping screws.Test results showed that the screwed-in threaded rod con-nections exhibited good pull-out behaviour with high withdrawal capacity and slip stiffness.Within a certain range,the withdrawal capacity increases considerably with the increase of embedment length,while the average interfacial shear stress shows the opposite tendency.The self-tapping screws played an important role on reducing the splitting of the timber and improving the withdrawal capacity and slip stiffness of the screwed-in threaded rod.Additionally,for the specimens with self-tapping screw reinforcements,the improvement of withdrawal capacity and stiffness when increasing the number of threaded rods are much more obvious than that of the speci-mens without the self-tapping screws,due to the change of failure modes.

STRENGTH DESIGN OF PREMIUM THREADED CASING CONNECTION

Using premium casing connections instead of API ones is one of the mosteffective technique to prevent casing failure. The factors contribute to the strength of premiumcasing connections are studied with FEA and full-scale test. The criterions are presented thatensure the connection's strength higher than the pipe. At the same time, the method is given todecrease the peak stress of the connection so as to improve its anticorruption property. At last,full-scale tests are done to test the strength of the connections designed with the methoddescribed, the results show that the connection's strength is higher than the pipe. This indicatedthat the method described is effective in designing premium casing connection.

INFLUENCE OF THREAD PITCH ON LOAD DISTRIBUTION ON THREADED END OF PRESSURE CYLINDER

One of the design methods for closing the end of a pressure cylinder is to screw down a screw plug on the threaded end of the cylinder. In this case, there is the problem of stress concentration in the threaded end of the pressure cylinder. To solve the problem, it is necessary to know accurately the load distribution on the threaded end of the cylinder. To find the load distribution on the threaded end of the pressure cylinder engaged with the screw plug, the following experiments are carried out. Applying the tensile load between the screw plug and the pressure cylinder and regarding the situation above as equivalent to the situation in which the internal pressure is applied, the load distribution is measured with the strain gauge. The influence of thread pitch on the load distribution on the threaded end of the cylinder is presented and an optimum pitch for design is discussed.

基于BL602的RT Thread移植方法研究

RT Thread是一款嵌入式实时操作系统,因其易于移植、可裁剪性好等特点备受广大嵌入式开发者的喜爱。BL602芯片内含一个32位的RISC V架构的微处理器,兼具高性能、超低功耗等特点。但目前关于将RT Thread实时操作系统移植到BL602芯片上还没有成熟的方案,针对这一现象,给出了将RT Thread移植到BL602上的详细方案。通过剪裁源码、修改配置文件、修改系统时钟、添加串口输出、采用轮询或中断回调实现串口输入等操作进行移植。实验结果表明,移植到BL602上的RT Thread操作系统可以正常运行,并且具备任务管理、任务调度等功能。本文提出的移植方案不仅可以降低BL602的开发难度、提高CPU的利用率,而且为其他RTOS移植提供了参考。

The dynamic response of a high-density polyethylene slow-release structure under launching overload

Based on the 60 mm artillery grenade,a slow-release structure was designed to reduce the severity of ammunitions response to accidental thermal stimulation and improve the thermal stability of ammunitions.The slow-release structure was made of high-density polyethylene(HDPE) and connected the fuse and the projectile body through internal and external threads.To study the safety of the slowrelease structure under artillery launching overload,mechanical analysis of the slow-release structure was simulated via finite element analysis(FEA).The impacts of various factors(e.g.,fuse mass,number of threads,and nominal diameter of internal threads of the slow-release structure) on the connection strength of the slow-release structure were studied.A strength-prediction model based on the fuse mass and internal thread parameters was established by fitting the maximum effective stress of the slowrelease structure.This led to good prediction results.In conclusion,this study provides references and theoretical support for the design of thermal protection structures insensitive to ammunition.

Summary and clinical application of Zhuang medicine medicated thread moxibustion

Zhuang medicine medicated thread moxibustion is a kind of external therapy with ethnic medicine characteristics that spreads in Guangxi Zhuang region.It has a wide range of clinical application and significant curative effect,and can be used to treat diseases such as internal medicine,surgery,dermatology,gynecology,pediatrics,and five sense organs.Through reviewing and combing the literature on the Zhuang medicine medicated thread moxibustion in recent years,this paper summarizes and prospects its clinical application,with a view to further explaining the basic principles and application rules of Zhuang medicine medicated thread moxibustion and digging its clinical value.

Evolution of microstructure, stress and dislocation of AlN thick film on nanopatterned sapphire substrates by hydride vapor phase epitaxy

A crack-free AlN film with 4.5 μm thickness was grown on a 2-inch hole-type nano-patterned sapphire substrates(NPSSs) by hydride vapor phase epitaxy(HVPE). The coalescence, stress evolution, and dislocation annihilation mechanisms in the AlN layer have been investigated. The large voids located on the pattern region were caused by the undesirable parasitic crystallites grown on the sidewalls of the nano-pattern in the early growth stage. The coalescence of the c-plane AlN was hindered by these three-fold crystallites and the special triangle void appeared. The cross-sectional Raman line scan was used to characterize the change of stress with film thickness, which corresponds to the characteristics of different growth stages of AlN. Threading dislocations(TDs) mainly originate from the boundary between misaligned crystallites and the c-plane AlN and the coalescence of two adjacent c-plane AlN crystals, rather than the interface between sapphire and AlN.

Security Threads and IoT Security

One of the technologies that have attracted the most attention recently across a variety of applications is the Internet of Things (IoT). The Internet of Things (IoT) is the combination of sensor, embedded computing, and communication technologies. The goal of the Internet of Things is to provide seamless services to anything, everywhere, at any time. The internet of things (IoT) technologies plays a vital role everywhere after the internet and information and communication technology, ushering in the fourth disruptive technology revolution (ICT). For real-time processing, communication, and monitoring, the smart items are linked together through wired or wireless connections. Implementing the IoT system presents security and privacy challenges since IoT devices are incompatible with current security standards based on tradition. This paper discusses IoT security strands, mitigation strategies, and privacy issues. This study’s major objective is to get more knowledge about security threats, mitigation techniques, and privacy concerns in IoT devices. The authors also mentioned a few cutting-edge technologies that can address general security problems. This study’s major objectives are to find research gaps in IoT security and match solution paradigms. The advent and rapid growth of the Internet of Things (IoT), which offers innumerable benefits, facilities, and applications including smart grids, smart homes, smart cities, and intelligent transportation systems (ITS), have an impact on everyone’s life. However, the deployment and use of sensing devices exposes IoT-based systems and applications to many security flaws and attacks. Furthermore, the lack of standardization brought on by the diversity of devices and technologies makes integrating security in the IoT a severe problem. The purpose of this review paper is to highlight the numerous security threats, challenges, and attacks that IoT-enabled applications face.

Causal Circular Narrative and Time-Space Construction of the Movie Little Big Woman

Chinese film Little Big Woman takes the father’s funeral as the main line to tell the story of family affection and real-life emotional entanglements.In the narrative with multiple clues,we go back to find the hidden reasons,and the gradually clear reflection of the past is related to the real situation of the characters.Causal cycle narrative is not only a narrative strategy,but also a narrative logic with deep Chinese traditional cultural and philosophical connotations.

瑞萨电子推出首款支持新Matter协议的Wi-Fi开发套件

作为物联网技术的卓越开发商,瑞萨将在未来所有Wi-Fi、BLE和Thread产品中支持Matter协议全球半导体解决方案供应商瑞萨电子(TSE:6723)今日宣布,推出首款支持新Matter协议的开发套件,同时宣布将在未来所有Wi-Fi、低功耗蓝牙?(BLE),和IEEE 802.15.4(Thread)方案中,以及最近收购的Dialog Semiconductor和Celeno Communications产品上,提供对Matter的支持。