Pipelines are widely used for the transportation of hydrocarbon fluids over millions of miles all over the world. The structures of the pipelines are designed to withstand several environmental loading conditions to ensure safe and reliable distribution from point of production to the shore or distribution depot. However, leaks in pipeline networks are one of the major causes of innumerable losses in pipeline operators and nature. Incidents of pipeline failure can result in serious ecological disasters, human casualties and financial loss. In order to avoid such menace and maintain safe and reliable pipeline infrastructure, substantial research efforts have been devoted to implementing pipeline leak detection and localisation using different approaches. This paper discusses pipeline leakage detection technologies and summarises the state-of-the-art achievements. Different leakage detection and localisation in pipeline systems are reviewed and their strengths and weaknesses are highlighted. Comparative performance analysis is performed to provide a guide in determining which leak detection method is appropriate for particular operating settings. In addition, research gaps and open issues for development of reliable pipeline leakage detection systems are discussed.

Recent Advances in Pipeline Monitoring and Oil Leakage Detection Technologies: Principles and Approaches

Identification of the structural damage mechanism of BFRP bars reinforced concrete beams using smart transducers based on time reversal method

A new analytical method of strain and deformation of pipeline under fault movement

Reinforced concrete is of vital importance in many civil and industrial structural applications. The effective bonding between steel and concrete is the core guarantee of the safe operation of the structures. Corrosion or other interface debonding in steel-concrete is a typical failure mode during the long service period of the structures, which can severely reduce the load-bearing capacity. The Non-destructive Evaluation technique has been applied to civil engineering structures in recent years. This paper investigates the evaluation of reinforced concrete structures that have interface defects, including the cross-sectional loss and cracks, by using the piezoceramic induced ultrasonic wave and time reversal method. Ultrasonic wave is used as actuating wave to obtain the signals with defect information. Time reversal method is applied to localize and characterize defect along the interface of the steel-concrete and to image the defect through the cross-sectional scanning. Experiments were conducted to perform Nondestructive Evaluation by using six reinforced concrete components with different levels of defects. The invisible damages were made by the cutting part of the steel and embedding a table tennis ball inside concrete structures. The results show that the time reversed method can locate and evaluate the defects along the steel reinforced concrete, and the obtained defect images at the cross-section of the concrete structure are accurate.

https://www.mdpi.com/1424-8220/18/12/4176/pdf

Detection of Defects in Reinforced Concrete Structures Using Ultrasonic Nondestructive Evaluation with Piezoceramic Transducers and the Time Reversal Method.

With the rapid development of the manufacturing industry, industrial automation equipment represented by computer numerical control (CNC) machine tools has put forward higher and higher requirements for the machining accuracy of parts. Compared with the multi-axis serial platform solution, the parallel platform solution is theoretically more suitable for high-precision machining equipment. There are many parallel platform solutions, but not one can provide a common physical platform to test the effectiveness of a variety of control algorithms. To achieve the goals, this paper is based on the Stewart six degrees of freedom parallel platform, and it mainly studies the platform construction. This study completed the mechanical structure design of the parallel platform. Based on the microprogrammed control unit (MCU) + pre-driver chip + three-phase full bridge solution, we have completed the circuit design of the motor driver. We wrote the program of MCU to drive six parallel robotic arms as well as the program of the parallel platform control center on the PC, and we completed the system joint debugging. The closed-loop control effect of the parallel platform workspace pose is realized.

/pdf/a-novel-architecture-of-a-six-degrees-of-freedom-parallel-319gcjcb.pdf

A Novel Architecture of a Six Degrees of Freedom Parallel Platform

Piezoceramic induced Lamb waves are often used for imaging based damage detection, especially for plate like structures. The dispersion effect of the Lamb waves deteriorates the performance of most of imaging methods, since the waveform of the dispersion signals will spread out. In this paper, an imaging method which can compensate the dispersion is developed. In the proposed method, the phase induced by the propagation distance is compensated firstly. After that, the phase deviation generated by the dispersion effect is compensated. Via the two compensations, the proposed method can derive an accurate location of the target with a clean imaging map. An experiment using a plate like structure with four piezoceramic transducer was conducted. In the experiment, the four piezoceramic sensors were used to obtain the signals of the scatterer that simulated the damage on an aluminum plate. The experimental results show that since the dispersion effect is compensated, the target's image based on the proposed method is about 10 cm × 14 cm, which is about a quarter of that of using the back-projection imaging method.

http://iopscience.iop.org/article/10.1088/1361-665X/26/2/025017/pdf

An imaging algorithm for damage detection with dispersion compensation using piezoceramic induced lamb waves

Due to the diffraction limit, the systems to localize signal sources used to suffer from the low resolution issue, which also occurs in the pipeline leakage localization. For a pressurized pipeline that carries gas, a leakage will generate a negative pressure wave (NPW) that propagates along the pipeline. The NPW can be detected by piezoceramic transducers that are bonded on the surface of the pipeline. Via processing NPW signals, the locations of the leakages can be obtained. However, since the wavelengths of the NPW signals are several meters, the resolution is meter sized. In this paper, a novel pipeline leakage localization method which can adjust the resolution is developed to improve the localization resolution. The proposed method includes a formula to adjust the localization resolution based on the time reversal technique. Via adjusting the parameter of the formula, various localization resolutions can be obtained. We investigated the performance of the proposed method in an experiment with a 55.8 m PVC pipeline equipped with two manually controllable leakage points. With the help of the piezoceramic transducers, the experimental results show that the proposed method can deliver the resolutions which represent a significant improvement, as compared with that of the conventional time reversal localization method. Furthermore, the proposed method can be used for other passive detection.

A Time Reversal Based Pipeline Leakage Localization Method With the Adjustable Resolution

With the continuous development of social economy, private cars have become more and more, and the traffic pressure is also increasing. To more accurately recognize vehicles violating traffic rules, the problem of recognition and optimization of license plate targets has become an urgent task with certain practical significance and guiding significance. In this paper, the license plate recognition (LPR) system is taken as the main research object, which is improved and optimized. Firstly, an improved neural network model is established by applying the improved convolutional neural network (CNN) algorithm to the license plate recognition system and based on the improved activation function, and the relevant experimental results are obtained; meanwhile compared with the traditional CNN model, the corresponding experimental results are obtained; finally, the experimental conclusions are obtained, i.e., the LPR system using improved CNN algorithm has better performance in recognizing license plate target and can more accurately recognize licence plates which are shielded. Therefore, the improved neural network model has great development potential in the application of the LPR system.

Recognition Optimization of License Plate Targets Based on Improved Neural Network Model

In this study, a novel field-oriented control (FOC) algorithm was proposed in a 60° coordinate system for controlling the speed of permanent magnet synchronous motors. The FOC algorithm consists of several parts in which the reference currents and feedback currents are transformed into the representation form in a 60° coordinate system. Current regulators are typically used in a 60° coordinate system to directly obtain the reference voltage vector. The proposed FOC structure was established by incorporating the space vector pulse width modulation algorithm in a 60° coordinate system. The proposed FOC structure simplified the FOC algorithm and reduced its computational burden. The feasibility of the proposed method was verified through simulations and experiments.

/pdf/a-novel-field-oriented-control-algorithm-for-permanent-1tb5l0w9.pdf

A Novel Field-Oriented Control Algorithm for Permanent Magnet Synchronous Motors in 60° Coordinate Systems

In the wireless power transfer systems using microwave, power conversion efficiency (PCE) represents a major challenge, especially at low input power levels. In this paper, a cooperative wireless power transmission method based on time reversal technology is developed to achieve a high input voltage. The performance of the proposed approach is investigated by using numerical experiments. Experimental results indicate that the input voltage can increase by more than 5.5 times over that of the general wireless power transmission.

Yue Song

Papers

An imaging algorithm for damage detection with dispersion compensation using piezoceramic induced lamb waves

A Time Reversal Based Pipeline Leakage Localization Method With the Adjustable Resolution

Recognition Optimization of License Plate Targets Based on Improved Neural Network Model

A Novel Field-Oriented Control Algorithm for Permanent Magnet Synchronous Motors in 60° Coordinate Systems

Cooperative wireless power transmission method based on time reversal technology