Vision-based displacement test method for high-rise building shaking table test

The vision-based displacement measurement system was developed, which using digital video camcorder to test the deformation of high-rise structures. It is more economical than contact and contact-less displacement sensors. A series of tests were conducted to investigate the precision, serviceability, and stability of the vision-based displacement method. The results show that, the proposed method can effectively test the dynamic displacement, moreover, the method can be effectively applied to test the displacement caused by vibration which contains various frequency components. Based on the system, the deformation of high-rise building structure was tested. The results show that, the displacement obtained by vision-based can illustrate the free-vibration characteristics of structure well, meanwhile, this method can test bidirectional displacement in shaking table test and practical engineering

Configuration Designs and Parametric Optimum Criteria of an Alkaline Water Electrolyzer System for Hydrogen Production

National Natural Science Foundation [51076134]; Fundamental Research Fund for the Central Universities, People's Republic of ChinaAn alkaline water electrolyzer system for hydrogen production and its semi-empirical equations are directly used to analyze and optimize the performance of the system. The results obtained through thermodynamic-electrochemical analysis show clearly that for such an alkaline water electrolyzer system, there exist some optimal values of the electrolyte concentration under different operating temperatures and the Joule heat resulting from the irreversibilities inside the alkaline water electrolyzer is larger than the additional heat needed in the water splitting process. Consequently, some new configurations for utilizing the surplus heat in the alkaline water electrolyzer are put forward to improve the performance of the system. The general performance of these new configurations is discussed, from which the lower bound of the operating current density is determined. In order to further optimize the characteristics of these configurations, a multi-objective function including both the efficiency and hydrogen production rate is originally put forward and used to determine the upper bound of the operating current density. The optimum criteria of main parameters and the optimally working region of the alkaline water electrolyzer system are given. In addition, the effects of some important parameters on the performance of the system are analyzed in detail

Efficiency Calculation and Configuration Design of a PEM Electrolyzer System for Hydrogen Production

A PEM electrolyzer system for hydrogen production is established and the corresponding efficiency is derived. Based on semi-empirical equations, thermodynamic-electrochemical modeling of water splitting reaction is systematically carried out. It is confirmed that the Joule heat resulting from the irreversibilities inside the PEM electrolyzer is larger than that needed in the water splitting process in the whole region of the electric current density. Some alternative configurations are designed to improve the overall performance of the system and the corresponding expressions of the efficiency are also derived. The curves of the efficiency varying with the electric current density are presented and the efficiencies of the different configurations are compared. The optimally operating region of the electric current density is determined. The effects of some of the important parameters on the performance of the PEM electrolyzer system are analyzed in detail. Some significant results for the optimum design strategies of a practical PEM electrolyzer system for hydrogen production are obtained.Fujian Natural Science Foundation; Fundamental Research Fund for the Central Universities, People's Republic of China [201112G006

Performance Analysis and Multi-Objective Optimization of a Molten Carbonate Fuel Cell-Braysson Heat Engine Hybrid System

A new hybrid system consisting of a molten carbonate fuel cell (MCFC) and a Braysson heat engine is established, in which multi-irreversibilities resulting from the overpotentials in the electrochemical reaction, heat leak from the MCFC to the environment, non-perfect regeneration in the regenerator, and finite-rate heat transfer in the Braysson heat engine are taken into account. Analytical expressions for the efficiency and power output of the hybrid system are derived through thermodynamic-electrochemical analyses, from which the general characteristics of the system are revealed and the optimum criteria of some of the main parameters such as the current density, efficiency and power output are given. The influence of the irreversible losses on the performance of the hybrid system is discussed. Moreover, a multi-objective function including both the power output and efficiency is introduced and used to further subdivide the parametric optimum regions according to different requirements which are often faced in the design and operation of practical fuel cell systems. The results obtained here are very general and may be directly used to derive the variously interesting conclusions of the hybrid system operated under different special cases.National Natural Science Foundation [51076134]; Fundamental Research Fund of Xiamen Universities, People's Republic of China [201112G006

Development of an integrated power distribution system laboratory platform using modular miniature physical elements: A case study of fault location

The main shortcomings of the software-based power engineering education are a lack of physical understanding of phenomena and hands-on experience. Existing scaled-down analogous educational power system platforms cannot be widely used for experiments in universities due to the high cost, complicated operation, and huge size. An integrated power distribution system laboratory platform (PDSLP) using modular miniature physical elements is proposed in this paper. The printed circuit board (PCB) and microelectronic technology are proposed to construct each physical element. Furthermore, the constructed physical elements are used to set up an integrated PDSLP based on modular assembly technology. The size of the proposed cost-efficient PDSLP is significantly reduced, and the reliability of the proposed PDSLP can be improved greatly because the signal transmission path is shortened and a number of welding points are reduced. A PDSLP for fault location in neutral non-effectively grounded distribution systems (NGDSs) is selected as a typical experimental scenario and one scaled-down distribution network with three feeders is subsequently implemented and discussed. The measured zero-sequence currents by our proposed PDSLP when a single-phase earth fault occurred can reveal the true features of the fault-generated signals, including steady-state and transient characteristics of zero-sequence currents. They can be readily observed and used for students to design corresponding fault location algorithms. Modular renewable energy sources and other elements can be designed, implemented and integrated into the proposed platform for the laboratory education of the active distribution networks in the future

Preparation and Separation Properties of Electrospinning Modified Membrane with Ionic Liquid Terminating Polyimide/Polyvinylpyrrolidone@Polydopamine

In this paper, superhydrophilic polyimide (PI) membranes were prepared using the electrostatic spinning method, capped with a hydrophilic ionic liquid (IL), and blended with polyvinylpyrrolidone (PVP). Using this preparation, the surface of the fiber membranes was coated in polydopamine (PDA) by means of an in-growth method. Scanning electron micrographs showed prepared blend films can form continuous fibers, for whom the distributions of diameter and pore were uniform. Post-modification (carried out by adding hydrophilic substances), the ability of the membrane surface to adhere to water was also significantly improved. The water contact angle was reduced from 128.97 ± 3.86° in unmodified PI to 30.26 ± 2.16°. In addition, they displayed a good separation effect on emulsified oil/water mixtures. The membrane flux reached a maximum value of 290 L·m−2·h−1, with a maximum separation efficiency reached of more than 99%. After being recycled 10 times, the separation efficiency maintained a level exceeding 95%. The purpose of this study is to demonstrate the simplicity and efficiency of this experiment, thereby providing new ideas for the future application of membrane separation technology in wastewater treatment

Configuration design and performance optimum analysis of a solar-driven high temperature steam electrolysis system for hydrogen production

Fujian Natural Science Foundation [2012J05097]; National Natural Science Foundation [51076134]; Zhejiang Natural Science Foundation; Fundamental Research Fund for the Central Universities, People's Republic of China [201112G006]A new solar-driven high temperature steam electrolysis system for hydrogen production is presented, in which the main energy consumption processes such as steam electrolysis processes, heat transfer processes, and product compression processes are included. The detailed thermodynamic-electrochemical modeling of the solid oxide steam electrolysis (SOSE) is carried out, and consequently, the electrical and thermal energy required by every energy consumption process are determined. The efficiency of the system is derived, from which the effects of some of the important parameters such as the operating temperature, component thickness of the SOSE, leakage resistance, effectiveness of heat exchangers, and inlet rate of water on the performance of the system are discussed. It is found that the efficiency attains its maximum when a proper current density is chosen. The ratio of the required electric energy to the total energy input of the system is calculated, and consequently, the problem how to rationally operate the solar concentrating beam splitting device is investigated. The results obtained will be helpful for further understanding the optimal design and performance improvement of a practical solar-driven high temperature steam electrolysis system for hydrogen production. Copyright (c) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved