Applications of Aluminum Alloys in Rail Transportation

This chapter focus on the latest applications of aluminum alloys in rail transportation field. The typical high-strength aluminum alloys used on high speed train is introduced. The unique properties of aluminum alloys are analyzed. The detailed application is illustrated including car-body, gear box and axle box tie rod. The main challenges encountered in the application are also mentioned. The key manufacturing techniques, such as casting, forming, welding, are analyzed. Finally, the future improvement directions for better application is summarized. It is expected to set up a bridge for materials providers, equipment manufacturers and end-users, thereby promoting the advance of manufacturing technology and application of aluminum alloys in wider fields

Ultra-high strength metal matrix composites (MMCs) with extended ductility manufactured by size-controlled powder and spherical cast tungsten carbide

The main challenge of particle reinforced metal matrix composites (MMCs) is balancing strength and ductility. This research uses type 420 stainless steel and spherical cast tungsten carbide (WC/W2C) with a similar powder size and range as raw powders to manufacture laser powder bed fusion (LPBF) 420 + 5 wt% WC/W2C MMCs. LPBF 420 + 5 wt% WC/W2C MMCs contain austenite, martensite, and W-rich carbides (WC/W2C, FeW3C, M6C, and M7C3) from nanometre to micrometre scale. The well-balanced composition creates a crack-free reaction layer between the reinforced particles and matrix. This reaction layer consists of two distinct layers, depending on the element concentration. The LPBF 420 + 5 wt% WC/W2C MMCs achieved an excellent compressive strength of ∼5.5 GPa and a considerable fracture strain exceeding 50 %. The underlying mechanisms for the improved mechanical properties are discussed, providing further insight to advance the application of MMCs via additive manufacturing

EMS software development for micro Grid-I

With the exhausted of conventional energy sources, the global energy problem is more and more severe. As a result, renewable and sustainable energy sources will take an important role in the future’s power system. The micro grid is known as a system in which renewable or non-conventional electricity generators employed. Considering the complexion and unpredictability of the micro grid, and the purpose of protecting the power equipments and decreasing the cost, it is important to design a EMS software of a micro grid, which is the objective of the whole project. However, for this project, it is mainly about the design of the PV mode of the software. The following report is divided into 6 chapters. The first chapter is an introduction of the project. Second chapter is the literature review, where gives detailed introduction on the micro grid, PV system, power flow analysis and MPPT. Chapter three discuss on the C# program language and gives detailed information of this software. Chapter four introduce the implement of the PV mode. Chapter five is on the micro grid overall simulation. Finally, the last two chapters will be the simulation result and the summary of this project. At the end of this project, a working software program was successfully developed and tested and it satisfies the initial requirements.Bachelor of Engineerin

Surface failure analysis of a field-exposed copper-clad plate in a marine environment with industrial pollution

The corrosion behavior and electrochemical migration mechanism of a copper-clad plate (PCB-Cu) in a marine atmospheric environment with industrial pollution were studied in field exposure experiments. The results showed that corrosion was initiated from activity locations with low potential. With extended exposure time, the amount of corrosion products increased and gradually formed a double layer structure. The inner layer corrosion products were mainly Cu2O; the outer layer mainly included CuCO3.Cu(OH)(2), Cu(OH)(2).CuO.HCl, CuSO4.3Cu(OH)(2) andCuSO(3).3Cu(OH)(2). When a 12V bias voltage was applied, an anomalous electrochemical migration (ECM) phenomenon was observed: a Cu dendrite was produced near the anode and migrated toward the cathode. Finally, ECM led to the bridge connection of the two metallization stripes and caused a short circuit in the PCB-Cu. (C) 2016 Elsevier B.V. All rights reserved

A Survey on Depth Ambiguity of 3D Human Pose Estimation

Depth ambiguity is one of the main challenges of three-dimensional (3D) human pose estimation (HPE). The recent strategies of disambiguating have brought significant progress and remarkable breakthroughs in the field of 3D human pose estimation (3D HPE). This survey extensively reviews the causes and solutions of the depth ambiguity. The solutions are systematically classified into four categories: camera parameter constraints, temporal consistency constraints, kinematic constraints, and image cues constraints. This paper summarizes the performance comparison, challenges, main frameworks, and evaluation metrics, and discusses some promising future research directions

A Survey on Depth Ambiguity of 3D Human Pose Estimation

Depth ambiguity is one of the main challenges of three-dimensional (3D) human pose estimation (HPE). The recent strategies of disambiguating have brought significant progress and remarkable breakthroughs in the field of 3D human pose estimation (3D HPE). This survey extensively reviews the causes and solutions of the depth ambiguity. The solutions are systematically classified into four categories: camera parameter constraints, temporal consistency constraints, kinematic constraints, and image cues constraints. This paper summarizes the performance comparison, challenges, main frameworks, and evaluation metrics, and discusses some promising future research directions

Quality Evaluation Algorithm for Chest Compressions Based on OpenPose Model

Aiming at the problems of the low evaluation efficiency of the existing traditional cardiopulmonary resuscitation (CPR) training mode and the considerable development of machine vision technology, a quality evaluation algorithm for chest compressions (CCs) based on the OpenPose human pose estimation (HPE) model is proposed. Firstly, five evaluation criteria are proposed based on major international CPR guidelines along with our experimental study on elbow straightness. Then, the OpenPose network is applied to obtain the coordinates of the key points of the human skeleton. The algorithm subsequently calculates the geometric angles and displacement of the selected joint key points using the detected coordinates. Finally, it determines whether the compression posture is standard, and it calculates the depth, frequency, position and chest rebound, which are the critical evaluation metrics of CCs. Experimental results show that the average accuracy of network behavior detection reaches 94.85%, and detection speed reaches 25 fps

Surface failure mechanism of PCB-ENIG in typical outdoor atmospheric environments

Electroless nickel/immersion gold (ENIG)-plated printed circuit boards (PCBs) were exposed to typical atmospheric environments in China for prolonged periods to understand the mechanism of corrosion failure. Results showed that the corrosion products that covered PCB-ENIG played a protective role by filling, covering, and coating surface defects. Under Turpan atmospheric environment, the plating layer was prone to damage easily, resulting in loss of protective properties. The corrosion mechanism was mainly microporous corrosion, in which halo-shaped macropores with a raised nucleus in the center were formed. When electrical bias was applied, PCB-ENIG was prone to electrochemical migration (ECM) caused by galvanic effects in the form of localized corrosion. Both Ni and Cu elements were involved in the ECM process. The synergistic effect of contaminated medium and high humidity is the critical factor of the ECM-induced PCB-ENIG corrosion. (C) 2017 Elsevier Ltd. All rights reserved

The Electrochemical Behavior and Characteristics of Passive Film on 2205 Duplex Stainless Steel Under Various Hydrogen Charging Conditions

The electrochemical behavior and the characteristic of 2205 duplex stainless steel (UNS S32205) under various hydrogen charging conditions in borate buffer solution containing chloride ion were evaluated by potentiodynamic measurements, electrochemical impedance spectroscopy, capacitance measurements (Mott-Schottky approach), and anodic polarization experiments. The results indicate that the hydrogen generated by the cathodic charging process decreased the corrosion resistance of 2205 duplex stainless steel, especially the pitting resistance of passive film. As a result of the hydrogen charging, the semiconductor characteristic of the passive film changed from n-type and p-type coexisting to only n-type existing, and the pitting susceptibility increased. Along with the charging process, the critical concentration of chloride for breakdown of passive film decreased and the repassivation process was prevented by hydrogen