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dynamic effect of water penetration on steel corrosion in carbonated mortar: A neutron imaging, electrochemical, and modeling study

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CEMENT 2022年 9卷

作者： Zhidong Zhang Pavel Trtik Fangzhou Ren Thilo Schmid Christopher H. Dreimol Ueli Angst Durability of Engineering Materials Institute for Building Materials ETH Zurich HCP G 31.1 Leopold-Ruzicka-Weg 4 Zurich 8093 Switzerland Laboratory for Neutron Scattering and Imaging (LNS) Paul Scherrer Institut (PSI) Villigen 5232 Switzerland Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin 150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin 150090 China Wood Materials Science Institute for Building Materials ETH Zürich Zürich 8093 Switzerland Cellulose and Wood Materials Laboratory EMPA Dübendorf 8600 Switzerland

Carbonation may potentially lead to corrosion of steel bars in reinforced concrete. This concern presents a major barrier against the implementation of sustainable low-clinker cementitious materials in the design of reinforced concrete structures. Various studies have documented the relationship between different equilibrium moisture states in carbonated concrete and the corrosion rate of the embedded steel. However, limited attempts were focused on visually observing the dynamic (time-dependent) behavior of moisture penetration into concrete and the related corrosion state and rate. Moreover, there is a lack of data on the local moisture state in the cementitious matrix in the steel-concrete interfacial zone. In this study, liquid water uptake in carbonated mortar was in-situ and over time monitored by neutron imaging. The corrosion state of embedded steel was monitored by means of electrochemical measurements. This combined experiment revealed that the arrival of the waterfront at the steel surface led to a sharp decrease of the steel potential. The corrosion rate increased from negligibly low values (<1 µm/year) to about 31 µm/year within a couple of minutes. Based on the neutron images, it is concluded that the moisture ingress through the concrete cover is locally affected by the heterogeneity of projected (depth-averaged) porosity distribution, and that large obstacles such as entrapped air have an effect. These observations were further confirmed by numerical simulation results of water transport, which also showed that liquid water permeability of the studied carbonated mortar determined by the inverse analysis is much higher than reported values in the literature. Overall, this study highlights the importance of considering the dynamic and coupled corrosion and moisture transport behavior during the periods which active corrosion can occur in carbonated concrete exposed to cyclic wetting/drying conditions.

关键词： Cement-based materials Carbonation Durability Corrosion Water imbibition Microstructure

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Study on Discharge Mechanism and Electromagnetic Radiation Characteristics of Trichel Pulsed Discharge Mode Transition

Study on Discharge Mechanism and Electromagnetic Radiation C...

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中国物理学会第二十二届全国静电学术年会

作者： Wang Chuang Chen Xi Tang Kai Li Peng-fei Science and Technology on Electromechanical Dynamic Control Laboratory China Beijing Institute of Technology Beijing 100081People's Republic of China

The Trichel pulse stage is an important stage of negative corona *** the applied voltage increases,there is a significant discharge mode transition process in the Trichel pulse *** this paper,the discharge mechanism and radiation characteristics of different discharge modes of Trichel pulse stage are studied by needle-plate discharge *** characteristics of Trichel pulse current during mode transition were *** the same time,the time-domain waveforms and spectrum characteristics of EM radiation signals are *** discharge mechanism and EM radiation characteristics of the Trichel pulse discharge mode transition process were theoretically *** results show that the Trichel pulse discharge will change from random pulse sequence mode to continuous pulse mode as the applied voltage *** the random pulse sequence mode,the Trichel pulse sequence appears *** randomness of the pulse sequence is due to the random generation of seed *** time domain waveform of EM radiation appears randomly in *** continuous pulse mode,Trichel pulses appear *** field emission caused by a stable cathode sheath is the main reason for maintaining pulse *** EM radiation signals appear *** frequency of the EM radiation signal does not change during the mode *** maximum amplitude of the signal decreases but the average power increases.

关键词： negative corona discharge Trichel pulse mode transition EM radiation

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Analysis and research of online measurement technology in inner bore of EML 7

Analysis and research of online measurement technology in in...

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2017 7th International Workshop on Computer science and Engineering, WCSE 2017

作者： Cao, Ronggang Dong, Erwa Xu, Xiangcai Beijing Institute of Technology Beijing China Science and Technology on Electromechanical Dynamic Control Laboratory China

ISBN: (纸本)9789811136719

With the development of science and technology, as a new concept weapon electromagnetic gun has important strategic significance. In the process of launch, there are some damages including wear, corrosion, gouging and transition for the rail-gun. In order to study damage mechanism of the electromagnetic rail-gun during launch, it is necessary to detect the bore profile of electromagnetic rail-gun. The bore of rail-gun has the structural characteristics of closed, invisible and narrow space makes inconvenience for the measurement of the contour, so the online measurement and analysis of the rail-gun bore is very important. By comparing different methods of measurement, laser triangle method of non-contact is the heart of the way using in this paper. The laser triangle method has the characteristics of high precision and non-contact, and can realize on-line nondestructive measurement of arbitrary cross section of the rail bore. Through the comparison of the ideal contour and the measured profile of the electromagnetic rail-gun, the damage profile can be obtained. Using this bore profile scanner of electromagnetic rail-gun designed by this method, we can get two-dimensional profile images.

关键词： Nondestructive examination

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Roll estimation algorithm based on Sage-Husa adaptive Kalman filtering with rotation criteria 13

Roll estimation algorithm based on Sage-Husa adaptive Kalman...

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2017 13th IEEE International Conference on Electronic Measurement & Instruments (ICEMI)

作者： Wang Jiawei Qi Keyu Xu Guotai Qian Rongzhao Yan Jie School of Astronautics Northwestern Polytechnical University Science and Technology on Electromechanical Dynamic Control Laboratory

ISBN: (纸本)9781509050369;9781509050352

According to the problem of increasing error caused by irresistible measuring noise in traditional EKF method within trajectory, a new solution of roll estimation for correction fuze, enlightened by axial output of gyro can be treated as rotation compensation for system noise, using SHAKF with rotation criteria is proposed. Firstly, based on the simulating comparison of estimation precision between traditional EKF and SHAKF methods, the result indicates that the roll measuring error of the new solution conspicuously lower than that of EKF's, the mean value of measuring error is 0.26 deg and the variance of that is 0.97 deg,that means the adaptivity of filter can follow the innovation to make estimated state convergence and eventually decreases the absolute error of roll angle. Furthermore, the new SHAKF algorithm is also verified by in-lab testing with MEMS three-axis turntable under an actually varying rotation setting, and the result shows that the estimation error always below 4.2 degs in dynamic range changing from 30 r/s to 1 r/s.

关键词： 2-D Course Correction Fuze dual-spin stabilized projectile roll estimation Sage-Husa adaptive Kalman filtering rotation compensation

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Roll angle estimation of guided gun-launched projectile using MEMS angular rate gyro and magnetometer

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Journal of Physics: Conference Series 2019年第1期1209卷

作者： R Z Qian G T Xu K H Yang Y Y Xu Science and Technology on Electromechanical Dynamic Control Laboratory 710065 Xi'an China Xi'an Institute of Electromechanical Information Technology Xi'an 710065 China

The previous method to estimate roll angle of guided gun-launched projectile can be completely invalid in case of GPS is disabled in battlefield. To solve that problem, this paper proposes roll angle estimation used MEMS angular rate gyro and magnetometer. Comparing to the previous method with GPS, the addition of magnetometer outputs increases the measurement accuracy, but increases the dimension and nonlinearity of the measurement model. Therefore the Extended Kalman Filter is introduced. Through trajectory simulation, this study indicates that the absolute roll estimation error is less than 7 degrees after 3 seconds in whole flight trajectory, which is completely met the guided system requirement.

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The Development Ideas and Experimental Verification on Cloud technology of Satellite control Center System

The Development Ideas and Experimental Verification on Cloud...

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IEEE Chinese Guidance, Navigation and control Conference (CGNCC)

作者： Yuan Wang Junlin Xiong Yang Zhang Ying Zhang Department of Automation University of Science and Technology of China Anhui China State key Laboratory of Astronautic Dynamic Xian Satellite Control Center Xian China

ISBN: (数字)9781538611715

ISBN: (纸本)9781538611722

With the continuous development of spaceflight industry in recent years, the number of on-orbit satellites is rapidly increasing, the scale of the Satellite control Center (SCC) is becoming larger and larger, and the complexity and difficulty of operating and maintenance of which is becoming more and more. Therefor the improvement of the reliability, recovery and the efficiency of resource utilization has become an important issue faced by the development of SCC system. As a resource management technology of computer system, cloud technology has a great advantage in improving resource utilization, reducing management costs and enhancing security, etc. Meanwhile these solutions of cloud technology service mode provide a good technical approach and ideas for new requirements of TT&C (track, telemetry and control). This paper summarizes the current application status of cloud technology in SCC system, puts forward the development ideas, and qualitative and quantitative analyzes the key technical indicators of the application of cloud technology in SCC system, which has certain reference significance for the subsequent development of SCC system.

关键词： Cloud computing Satellites Servers Virtualization Real-time systems Telemetry Software

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The Design of Satellite Telemetry Data Storage and Analysis Software based on HBase Database*

The Design of Satellite Telemetry Data Storage and Analysis ...

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IEEE Chinese Guidance, Navigation and control Conference (CGNCC)

作者： Yuan Wang Junlin Xiong Yang Zhang Xun Fang Department of Automation University of Science and Technology of China Anhui China State key Laboratory of Astronautic Dynamic Xi’an Satellite Control Center Xi’an China

ISBN: (数字)9781538611715

ISBN: (纸本)9781538611722

After decades of development, the Satellite control Center (SCC) has accumulated massive spacecraft telemetry data including all history information of on-orbit working status data of satellites and spaceships. The current SCC system adopts the architecture of a relational database mounted by NAS to manage data. In recent years, with more refined management of on-orbit satellites, the long-term trend analysis of satellite telemetry data is needed on qualitative quantitative analysis of satellite components' performance, satellite failure status and so on. The performance of the current database system is poor, and the big data processing capacity is limited, which is difficult to meet engineering requirements. With the rapid development of the big data technology, a series of processing architectures adapting to mass data are generated, which provide the technical approach for solving the problem of telemetry data analysis and mining. The paper designs the satellite telemetry data storage and analysis architecture based on HBase, which is the first time to introduce the non-relational database into the design of SCC database, breaks through the current system bottlenecks. The prototype experiment shows that it is able to realize the second level response of telemetry data extraction and analysis in condition of the large time span, which has a significance for further engineering application.

关键词： Telemetry Satellites Databases Computer architecture Market research Servers Data analysis

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Design, Simulation and Fabrication of a Time-Delay Device Based on Micro-Channel

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IOP Conference Series: Materials science and Engineering 2019年第4期563卷

作者： Qiaoran Zhao Li Sui Ping Song School of Mechatronical Engineering Beijing Institute of Technology Beijing 100081 China Science and Technology on Electromechanical Dynamic Control Laboratory Beijing 100081 China

With the development of micro-machining technology, the application of microchannel is becoming more and more popular. In this paper, we design a set of time-delay device based on micro-channel and micro-fluidics technology. This paper describes the time-delay device's working principle and analyses the micro-channel's flow characteristics by simulation method based on Coventerware. From studies on the micro-channel's cross section, geometry and dimension parameters, the micro-channel's optimal form and dimension can be obtained. Finally, this paper chooses ultra-machining process to fabricate the time-delay device.

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The vertical placement ultra - thin flameproof baffle of the fuze

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Journal of Physics: Conference Series 2019年第1期1209卷

作者： C C Sun H B Liu X Zhao Xi'an Institute of Electromechanical Information Technology Xi'an 710065 China Science and Technology on Electromechanical Dynamic Control Laboratory Xi'an Shaanxi 710065 China

In order to meet the operational requirements of a new type of intelligent small penetrating submunition fuze with large overload of target base, a new type of ultra-thin vertical fuze flameproof baffle is proposed. Vertical arrangement of fuze ultra-thin flame-proof board uses the three layers of different vertical composite plate structure of metal materials, the overall size for the 1.6mm thickness, the length of vertical is 20mm, upper and lower layer 0.3mm thickness of tungsten-copper alloy plate, respectively, the middle layer of 304 stainless steel. The simulation and test results show that the ultra-thin vertical fuze baffle can resist the penetration overload of 120,000g, and guarantee the safety of 12m dropping and explosion isolation.

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Theoretical analysis and experimental study of a perforated piezoelectric cantilever

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IOP Conference Series: Materials science and Engineering 2019年第3期563卷

作者： Huaiwei Su Li Sui Ping Song Yousong Lu School of Mechatronical Engineering Beijing Institute of Technology Beijing 100081 China Science and Technology on Electromechanical Dynamic Control Laboratory Beijing 100081 China

Piezoelectric energy harvesters have been studied extensively because they show considerable promise for use in both military and commercial applications. In order to improve the output capability of the piezoelectric energy harvester, the perforated piezoelectric cantilevers were designed in this work. To study how the hole on the cantilever affected the output characteristics, this paper analysed the position and size of the hole separately. The results show that, perforating the cantilever can cause stress concentration of the piezoelectric cantilever, and improve the output capacity.

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