U75V rail steel rods underwent continuous-drive friction welding (CDFW). Joint properties were evaluated through microstructural analysis and mechanical testing (tensile, impact, microhardness). The thermo-mechanical behaviour of the CDFW process was simulated by finite element method, while a computed continuous cooling transformation diagram used to predict phase transformation, microstructures, hardness variations. By reducing spindle speed 1000 r/min, peak temperature in weld centre zone...

Underwater communication is particularly challenging for small submarine robots that have limited power and size constraints. Inspired by weakly electric fish, a novel current (termed electrocommunication) system has been developed underwater in our previous studies. However, collision problems sometimes occur during multiple because the electrocommunication network shares common channel. In this paper, new CSMA/CA-based presented to solve problem. An efficient circuit channel state (busy or...

In the present paper, continuous-drive friction welding (CDFW) technology has been successfully applied to join U75V rail steel. The base metal (BM) of steel is lamellar pearlite, and weld zone could be clearly divided into three subzones (i.e., heat affected zone, thermo-mechanical (TMAZ), central (CWZ)). Electron back-scattered diffraction examinations revealed martensitic evolution in TMAZ CWZ, suggesting that experienced high temperature, severe plastic deformation, fast cooling rate...

Current underwater communication typically includes acoustic, optical, radio frequency, and magneto-inductive channels. Wireless sensor networks are usually built on these four However, vulnerable to complex aquatic environments. In nature, weakly electric fish able communicate electrically (called electrocommunication), which is 'invisible' most other animals, convey information such as species, courtship, environmental conditions. Inspired by the electrocommunication of fish, an artificial...

A nuclear power plant is a complex coupling system, which features multi-physics between reactor physics and thermal-hydraulics in the core, as well multi-circuit primary circuit secondary by shared steam generator (SG). Especially pebble-bed modular HTR plant, different supply modules are further coupled together through main pipes related equipment circuit, since special configuration of multiple connects to turbine. The JFNK (Jacobian-Free Newton–Krylov) method provides promising...

Underwater wireless communication technology has been restricting the development of undersea resources for decades. We have proposed an effective underwater method (electrocommunication) small robots in our previous studies. In this article, we further study how electrode distance/spacing affects range electrocommunication between robotic fish models. The working principle is simplified by electric dipole model. Based on model, maximum theoretical distance derived as <tex...

System model is fundamental for accurate motion control of the robot. However, due to complexity aquatic environments and special fin-driven structure, it difficult dynamically system robotic fish. This paper proposes an experimental modeling method yaw a freely swimming fish through identification. Tail deflection corresponding angular velocity robot are obtained by series open-loop experiments. Both notch filter low-pass adopted get rid oscillation disturbance in velocity. By simplifying...

Due to the challenging communication and control systems, few underwater multi-robot coordination systems are currently developed. In nature, weakly electric fish can organize their collective activities using electrocommunication in turbid water. Inspired by this mechanism, we developed an artificial system for robots our previous work. study, coordinate a group of bio-inspired electrocommunication. We first design time division multiple access (TDMA) network protocol avoid conflicts during...

To research the optimal path problem in wireless sensor network (WSN), Genetic Algorithms, Differential Evolution, Particle Swarm Optimization and Dijkstra algorithm are used this study. Experimental comparisons show that different algorithms may represent obvious difference under size. During small-scale network, needs least run time obtains highest success rate to find solutions. However, Evolution provide better performance than big-scale network. In a word, up greater adaptability among...

This article presents a rotatory friction welding (RFW) method for U75V steel rail, aiming to mitigate challenges related property discrepancies between the as-welded joints and rail base metal (BM) narrow heat-affected zone (HAZ) in conventional flash-butt (FBW) joints. A rotational intermediate plate is designed rails with non-axisymmetric cross-sections, necessitating stationary during RFW. Advantages include achieving relatively uniform heat input maintaining peak temperature of contact...

The decay branch ratio is evaluated nuclear data related to the heat calculation in reactor safety analysis. Decay are inherently subjected “sum-to-one” constraint, making it difficult generate perturbed samples while preserving their suggested statistics a library of data. Therefore, stochastic-sampling-based uncertainty analysis method hindered quantifying contribution calculation. In present work, two alternative sampling methods introduced, based on Dirichlet and generalized...

An ER430LNb ferritic stainless steel wire was used for a gas metal arc welding (GMAW) test. The characteristics of droplet transfer and its corresponding voltage current waveforms were investigated using high-speed camera synchronous acquisition electrical signals. weld formation, patterns microstructures under different parameters observed, the effect level on frequency discussed. As results show, there three typical during GMAW wire, namely short circuit transfer, mix spray transfer. With...

Visible light communication(VLC) has shown in explosive growth recent years, and LEDs based visible wireless communication the potential to change lives future with applications such as LiFi, smart lighting indoor positioning. Due low bandwidth of LED devices, VLC systems using LDs(laser diodes) sources can achieve faster transmission speed. In this paper, we propose a high-speed system automatic alignment function red laser. Each tranceiver be moved angle view another, aligned real time...

Two novel methods of obtaining microduplex structures, ferrite plus spherical carbides, in ultrahigh strength steels (~2000MPa) are introduced. One is through an adequate deformation just below the austenite-ferrite equilibrium transformation temperature (i.e. Ae 3 temperature, ~983K) followed by water quenching. The directly leads to formation a (ferrite carbides) structure. microstructure evolution during includes pearlite transformation, cementite spheroidization and recrystallization....

Matrix is a mathematical object, commonly used in scientific computing and engineering calculation.In the data structure we are not interested itself, but how to store elements matrix, make various operations can run effectively.The main purpose of compressed storage more same nonzero share unit according distribution matrix element, while zero don't allocate space.In this paper, studied multi-vector problems lower half banded obtained row column priority address mapping function for first...