Design of a Bimorph Piezoelectric Energy Harvester for Railway Monitoring

Li, Jingcheng,Jang, Shinae,Tang, Jiong The Korean Society for Nondestructive Testing 2012 한국비파괴검사학회지 Vol.32 No.6

Wireless sensor network is one of prospective methods for railway monitoring due to the long-term operation and low-maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree-of-freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from $2.06m/s^2$ base excitation compared to stand-alone piezoelectric energy harvester without tip mass.

New Development of Researches in Psychology of Physical Education in China

Li Jingcheng,육조영 한국스포츠리서치 2005 한국 스포츠 리서치 Vol.16 No.3

Design of a Bimorph Piezoelectric Energy Harvester for Railway Monitoring

Jingcheng Li,Shinae Jang,Jiong Tang 한국비파괴검사학회 2012 한국비파괴검사학회지 Vol.32 No.6

Wireless sensor network is one of prospective methods for railway monitoring due to the long-term operation and low-maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree-of-freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s<SUP>2</SUP> base excitation compared to stand-alone piezoelectric energy harvester without tip mass.

Robust Stability Conditions for DMC Controller with Uncertain Time Delay

Yang Ge,Jingcheng Wang,Chuang Li 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.2

For Networked Control Systems (NCSs), the conventional Dynamic Matrix Control (DMC) may not applicable due to the unknown transmission delay. The uncertain time delay was usually converted to constant time delay by using registers. This paper addresses the stability problem for single-input-single-output (SISO) linear NCSs with uncertain time delay via DMC controller. A novel DMC controller which is effective for such NCSs has been proposed. Applying Jury’s dominant coefficient lemma, the sufficient stability and stabilization conditions are presented. Finally, numerical examples are given to demonstrate the theoretical results.

H_∞ Control of Networked Control Systems with Packet Disordering with an Improved Prediction-based Method

Yan Song,Jingcheng Wang,Yuanhao Shi,Chuang Li 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.5

This paper is concerned with H_∞ control of networked control systems (NCSs) with both network-induced delay and packet disordering taken into account. A switching-based method depends on different cases of prediction numbers is presented to model the NCSs as a switched system. With the application of an improved prediciton-based method to compensate for the time delay and packet disordering, H_∞ controller is designed by solving the linear matrix inequalities (LMIs). The proposed method can be applied variously due to all kinds of prediciton numbers of the consective disordering packet have been considered, which means that our techniques are less conservative than existing lit-eratures. Finally numerical examples and simulations are used to illustrate the effectiveness and valid-ity of the proposed switching-based method and the improved prediction-based H∞ controller design synthesis.

Magnetic Flux Leakage Image Enhancement using Bidimensional Empirical Mode Decomposition with Wavelet Transform Method in Oil Pipeline Nondestructive Evaluation

Liang Chen,Jingcheng Li,Yakai Zeng,Yongqiang Chen,Wei Liang 한국자기학회 2019 Journal of Magnetics Vol.24 No.3

The magnetic flux leakage (MFL) method is the most widely used and cost-effective inspection technique for oil pipeline. However, noise is inevitable in the process of data collection; thus, the image enhancement method can be more intuitive to identify the defects in an oil pipeline MFL inspection. In this paper, the bidimensional empirical mode decomposition (BEMD) method has been used to study oil pipeline MFL images. The MFL image is decomposed into a finite number of two-dimensional intrinsic mode functions (BIMF) and a residual component by the BEMD. The wavelet transform (WT) was used to remove the noise in the BIMF. The image was then reconstructed by retaining the basic information and removing the noise. The results show that the noise is effectively removed and the detail of the MFL image is well preserved. Thus, the BEMD with WT method for oil pipeline MFL image enhancement is better than the mean filtering method and the WT method.

Phosphorus removal and recovery from wastewater by highly efficient struvite crystallization in an improved fluidized bed reactor

Bin Lu,Jingcheng Xu,Ming Zhang,Weihai Pang,Li Xie 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.11

Phosphorus is the crucial factor causing eutrophication in the aquatic ecology. The high phosphorus loading in water bodies may result from the direct disposal of untreated wastewater. In this study, a fluidized bed reactor (FBR) was specially developed to remove and recover phosphorus effectively and efficiently via struvite crystallization. Different physiochemical and hydraulic conditions, including hydraulic retention time (HRT), pH, and molar ratios of Mg : P, N: P and Ca :Mg, were explored to optimize the performance of this improved FBR. For the continuous operating trials, promising removal and recovery efficiencies were achieved at the phosphorus concentration of 25.0mg/L: >90% of phosphorus could be removed under the optimum condition (pH=9, HRT=12 h, Mg : P=1.25 and N : P= 7.5). Increasing the recycle flow rate and prolonging the contact time could also enhance the FBR efficiency. The crystal products obtained in FBR were analyzed in terms of composition and structure. Results indicated that almost pure struvite (>99%) was achieved at low calcium concentrations, which could be considered as a high quality fertilizer.

Rapid full-scale expansion joint monitoring using wireless hybrid sensor

장신애,Sushil Dahal,Jingcheng Li 국제구조공학회 2013 Smart Structures and Systems, An International Jou Vol.12 No.4

Condition assessment and monitoring of bridges is critical for safe passenger travel, public transportation, and efficient freight. In monitoring, displacement measurement capability is important to keep track of performance of bridge, in part or as whole. One of the most important parts of a bridge is the expansion joint, which accommodates continuous cyclic thermal expansion of the whole bridge. Though expansion joint is critical for bridge performance, its inspection and monitoring has not been considered significantly because the monitoring requires long-term data using cost intensive equipment. Recently, a wireless smart sensor network (WSSN) has drawn significant attention for transportation infrastructure monitoring because of its merits in low cost, easy installation, and versatile on-board computation capability. In this paper, a rapid wireless displacement monitoring system, wireless hybrid sensor (WHS), has been developed to monitor displacement of expansion joints of bridges. The WHS has been calibrated for both static and dynamic displacement measurement in laboratory environment, and deployed on an in-service highway bridge to demonstrate rapid expansion joint monitoring. The test-bed is a continuous steel girder bridge, the Founders Bridge, in East Hartford, Connecticut. Using the WHS system, the static and dynamic displacement of the expansion joint has been measured. The short-term displacement trend in terms of temperature is calculated. With the WHS system, approximately 6% of the time has been spent for installation, and 94% of time for the measurement showing strong potential of the developed system for rapid displacement monitoring.

Quantitatively Decoupling the Impact of Preload and Internal Mechanism Motion on Pyrotechnic Separation Shock

Shihui Xiong,Yanhua Li,Yaokun Ye,Jingcheng Wang,Huina Mu,Yuquan Wen 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.5

Pyrotechnic separation devices are widely used in space separation systems. However, these devices produce high-frequency, high-amplitude shock responses during operation, which endangers the safety of space systems. Hence, it is imperative to study the shock mechanism and characteristics during the unlocking process of a pyrotechnic separation device. This paper uses LS-DYNA finite element software and experiments to analyze the separation characteristics of the separation nut and predict its shock response, quantitatively decoupling the impact of preload and internal mechanism motion on separation shock. The results indicate that the shock response caused by the impact on the inner sleeve is the primary contributor to the total shock response of the separation nut (approximately 55% of the total response). The shock response caused by the release of the strain energy is very small, accounting for less than 5% of the total shock response. Adjusting the preload force without changing the charge and structure of the separation device did not have a clear impact on reducing the shock. This study shows that the shock of the separation device can be decreased by reducing the impact on the inner sleeve.

Rapid full-scale expansion joint monitoring using wireless hybrid sensor

Jang, Shinae,Dahal, Sushil,Li, Jingcheng Techno-Press 2013 Smart Structures and Systems, An International Jou Vol.12 No.3

Condition assessment and monitoring of bridges is critical for safe passenger travel, public transportation, and efficient freight. In monitoring, displacement measurement capability is important to keep track of performance of bridge, in part or as whole. One of the most important parts of a bridge is the expansion joint, which accommodates continuous cyclic thermal expansion of the whole bridge. Though expansion joint is critical for bridge performance, its inspection and monitoring has not been considered significantly because the monitoring requires long-term data using cost intensive equipment. Recently, a wireless smart sensor network (WSSN) has drawn significant attention for transportation infrastructure monitoring because of its merits in low cost, easy installation, and versatile on-board computation capability. In this paper, a rapid wireless displacement monitoring system, wireless hybrid sensor (WHS), has been developed to monitor displacement of expansion joints of bridges. The WHS has been calibrated for both static and dynamic displacement measurement in laboratory environment, and deployed on an in-service highway bridge to demonstrate rapid expansion joint monitoring. The test-bed is a continuous steel girder bridge, the Founders Bridge, in East Hartford, Connecticut. Using the WHS system, the static and dynamic displacement of the expansion joint has been measured. The short-term displacement trend in terms of temperature is calculated. With the WHS system, approximately 6% of the time has been spent for installation, and 94% of time for the measurement showing strong potential of the developed system for rapid displacement monitoring.