Evaluation of SHM With the Electromechanical Impedance Method Using a High Voltage Excitation Signal in High Frequencies

2019 ◽  
Author(s):  
Eric C. Nolan ◽  
Mohsen Safaei ◽  
Steven R. Anton
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Impedance Method ◽  
Fe Model ◽  
Structure Damage ◽  
Electromechanical Impedance ◽  
Excitation Signal ◽  
Voltage Amplifier ◽  
High Speed Data Acquisition

Abstract Structural health monitoring (SHM) has originally been used for static structures. With the development of high-speed data acquisition technology, SHM systems can monitor structures in seconds. Advanced SHM systems for use in dynamic environments require operation in the microsecond timescale. One promising approach is the electromechanical impedance (EMI) technique. The EMI method monitors the impedance of a structure, and damage is indicated by changes in the impedance. Standard impedance measuring hardware are not practical for microsecond detection due to their slow sampling speeds. Faster impedance measuring techniques have been developed and allow for customizable excitation signals. Researchers have also considered taking measurements at higher frequencies to decrease the measurement time. Past works indicate sensitivity to damage is limited above 600 kHz. The goal of this study is to evaluate the sensitivity of the EMI method to damage with a high voltage excitation signal. It was hypothesized that increasing the voltage would increase damage sensitivity at higher frequencies. In this study, the amplitude of the excitation signal was increased using a high frequency voltage amplifier. A PZT disk bonded to a cantilevered aluminum beam was used as the test structure. Damage was created by decreasing the length of the beam. Finite element (FE) simulation was also employed to achieve a better understanding of the experiment. From the results of the experiment and FE model, using a higher excitation voltage has proven not to increase the sensitivity level of the EMI method. Higher voltages do improve the precision of the measurement by increasing the signal to noise ratio.

scholarly journals Digital imaging fluorescence microscopy: spatial heterogeneity of photobleaching rate constants in individual cells.

1985 ◽  
Vol 100 (4) ◽  
pp. 1309-1323 ◽  
Author(s):  
D M Benson ◽  
J Bryan ◽  
A L Plant ◽  
A M Gotto ◽  
L C Smith
Keyword(s):  
Rate Constants ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Experimental Conditions ◽  
Excitation Light ◽  
Illumination Time ◽  
Probe Concentration ◽  
High Speed Data Acquisition ◽  
High Speed Data

Photobleaching and related photochemical processes are recognized experimental barriers to quantification of fluorescence by microscopy. We have measured the kinetics of photobleaching of fluorophores in living and fixed cells and in microemulsions, and have demonstrated the spatial variability of these processes within individual cells. An inverted fluorescence microscope and a high-sensitivity camera, together with high-speed data acquisition by a computer-controlled image processor, have been used to control precisely exposure time to excitation light and to record images. To improve the signal-to-noise ratio, 32 digital images were integrated. After correction for spatial variations in camera sensitivity and background fluorescence, the images of the relative fluorescence intensities for 0.065 micron2 areas in the object plane were obtained. To evaluate photobleaching objectively, an algorithm was developed to fit a three-parameter exponential equation to 20 images recorded from the same microscope field as a function of illumination time. The results of this analysis demonstrated that the photobleaching process followed first-order reaction kinetics with rate constants that were spatially heterogeneous and varied, within the same cell, between 2- and 65-fold, depending on the fluorophore. The photobleaching rate constants increased proportionally with increasing excitation intensity and, for benzo(a)pyrene, were independent of probe concentration over three orders of magnitude (1.25 microM to 1.25 mM). The propensity to photobleach was different with each fluorophore. Under the cellular conditions used in these studies, the average rates of photobleaching decreased in this order: N-(7-nitrobenz-2-oxa-1,3-diazole)-23,24-dinor-5-cholen-22-amine-3 beta-ol greater than acridine orange greater than rhodamine-123 greater than benzo(a)pyrene greater than fluorescein greater than tetramethylrhodamine greater than 1,1'dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine. The photobleaching appears to be an oxidation reaction, in that the addition of saturated solutions of Na2S2O5 to mineral oil microemulsions eliminated photobleaching of N-(7-nitrobenz-2-oxa-1,3-diazole)-23,24-dinor-5-cholen-22-amine-3 beta-ol or benzo(a)pyrene. We identified experimental conditions to observe, without detectable photobleaching, fluorophores in living cells, which can not be studied anaerobically. Useful images were obtained when excitation light was reduced to eliminate photobleaching, as determined from zero-time images calculated from the exponential fit routine.(ABSTRACT TRUNCATED AT 400 WORDS)

Researches on Channel Mismatch Effects in Time-Interleaved ADC System

2013 ◽  
Vol 655-657 ◽  
pp. 978-983
Author(s):  
Hui Yong Sun ◽  
Peng Cao
Keyword(s):  
High Speed ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Mismatch Error ◽  
Signal To Noise ◽  
Gain Error ◽  
Channel Mismatch ◽  
High Speed Data Acquisition ◽  
Interleaved Adc ◽  
Time Interleaved

The Time-Interleaved ADC（TIADC) is an effective method for implement ultra high-speed data acquisition. However, the errors of channel mismatch are seriously degrade the signal-to-noise ratio of the system, such as Time-skew error, Gain error and Offset error. This paper have done some researches and analysis, and given the modeling of the three channels mismatch. What's more, it also given a detailed analysis of error and the method of measure it, derived the formula of signal to noise and distortion ratio(SINAD) and spurious free dynamic range(SFDR). All of them provide a reference for the tolerance range of TIADC channel mismatch error. Meanwhile, the result of this paper has provided a theoretical basis for eliminating TIADC channel mismatch error.

scholarly journals Separate-type scanner and wideband high-voltage amplifier for atomic-resolution and high-speed atomic force microscopy

2013 ◽  
Vol 84 (4) ◽  
pp. 043705 ◽  
Author(s):  
Kazuki Miyata ◽  
Satoshi Usho ◽  
Satoshi Yamada ◽  
Shoji Furuya ◽  
Kiyonori Yoshida ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
High Voltage ◽  
High Speed ◽  
Atomic Resolution ◽  
Force Microscopy ◽  
Separate Type ◽  
Atomic Force ◽  
Voltage Amplifier

High-speed electron counting system for TV scan-rate secondary-electron images of SEM

1991 ◽  
Vol 49 ◽  
pp. 512-513
Author(s):  
S. Yamada ◽  
T. Ito ◽  
K. Gouhara ◽  
Y. Uchikawa
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Pulse Height ◽  
Counting System ◽  
Main Amplifier ◽  
Electron Counting ◽  
Scan Rate ◽  
High Speed Data Acquisition ◽  
High Speed Data ◽  
New System

We reported a system for counting secondary electrons (SEs), with which SE image quality of SEM such as signal to noise ratio (SNR) and linearity were improved, in particular under the condition of low irradiation. The system had been developed for slow-scan rates (over 6 sec/flame). The TVscan rate (1/30 sec/frame) is often used to avoid charging of insulators and biological specimens. We developed a high speed electron counting system with which SE images can be obtained in the TVscan rate. This paper describes the new system attached to an SEM, and some experimental results obtained with it.A schematic diagram of the new system is shown in FIG.1, which consists of four main parts; Everhart-Thornley type detector (DT), main amplifier (MA), counter (CNT) and image processor (IP). In designing the system we took precautions for high speed data acquisition in the TV-scan rate. As described in the previous papers, the thermal noise and the fluctuations of the pulse height of the SE signal contained in the output of the DT can be removed through the CNT.

Design Aspects of a High-Speed High-Voltage PMSM for Aerospace Application

2017 ◽  
Vol 10 (3) ◽  
pp. 122
Author(s):  
Flur Ismagilov ◽  
Nikita Uzhegov ◽  
Vyacheslav Vavilov ◽  
Denis Gusakov
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Aerospace Application

A High-Voltage High-Speed AC Switch Based on Controlled Vacuum Surge Arresters

2018 ◽  
Vol 4 (4) ◽  
pp. 4-13
Author(s):  
Vladimir A. SIDOROV ◽  
◽  
Gennady D. DOMASHENKO ◽  
Marat R. AKHMETGAREYEV ◽  
Yurii V. SHCHERBAKOV ◽  
...  
Keyword(s):  
High Voltage ◽  
High Speed ◽  
Surge Arresters

40 Gb/s High-speed mode-division multiplexing transmission employing NRZ modulation format

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Rabiu Imam Sabitu ◽  
Nafizah Goriman Khan ◽  
Amin Malekmohammadi
Keyword(s):  
System Performance ◽  
High Speed ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Threshold Power ◽  
Modulation Format ◽  
Transmission Distance ◽  
Mode Division Multiplexing ◽  
Speed Mode

AbstractThis report examines the performance of a high-speed MDM transmission system supporting four nondegenerate spatial modes at 10 Gb/s. The analysis adopts the NRZ modulation format to evaluate the system performance in terms of a minimum power required (PN) and the nonlinear threshold power (PTH) at a BER of 10−9. The receiver sensitivity, optical signal-to-noise ratio, and the maximum transmission distance were investigated using the direct detection by employing a multimode erbium-doped amplifier (MM-EDFA). It was found that by properly optimizing the MM-EDFA, the system performance can significantly be improved.

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