Impedance characteristics of Aluminum Alloy stranded conductors in the frequency range 40 Hz to 150 kHz

Author(s):  
Andras Mohos ◽  
Jozsef Ladanyi
2019 ◽  
Vol 174 ◽  
pp. 105862 ◽  
Author(s):  
András Mohos ◽  
József Ladányi ◽  
Dániel Divényi
Keyword(s):  

Author(s):  
Taehee Han ◽  
Hossein Salehfar ◽  
Nilesh V. Dale ◽  
Mike D. Mann ◽  
Jivan N. Thakare

Impedance characteristics of a 6 kW proton exchange membrane (PEM) electrolyzer stack are presented under various operating conditions. An electrolyzer stack was operated under room temperature and partial current range (0 to 80 A). The whole stack impedance spectrums were measured by three different power supply configurations. The total sweeping frequency range (0.5 Hz to 20 kHz) is divided into low frequency (0.5 to 20 Hz), middle frequency (20 Hz to 1 kHz), and high frequency (1 to 20 kHz). Each frequency range required a different measurement setup to measure the whole stack impedance data. In this study, the partial impedance spectrums at low and high frequency ranges are successfully measured and analyzed. The measured data is verified with Kramers-Kronig relations. Measurement issues at the middle frequency region are discussed.


Solid Earth ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 2351-2368
Author(s):  
Bogdan Grecu ◽  
Felix Borleanu ◽  
Alexandru Tiganescu ◽  
Natalia Poiata ◽  
Raluca Dinescu ◽  
...  

Abstract. After the World Health Organization declared COVID-19 a pandemic in March 2020, Romania followed the example of many other countries and imposed a series of restrictive measures, including restricting people's mobility and closing social, cultural, and industrial activities to prevent the spread of the disease. In this study, we analyze continuous vertical component recordings from the stations of the Romanian Seismic Network – one of the largest networks in Europe, consisting of 148 stations – to explore the seismic noise variation associated with the reduced human mobility and activity due to the Romanian measures against COVID-19 in detail. We focused our investigation on four frequency bands – 2–8, 4–14, 15–25 and 25–40 Hz – and found that the largest reductions in seismic noise associated with the lockdown correspond to the high-frequency range of 15–40 Hz. We found that all the stations with large reductions in seismic noise (>∼  40 %) are located inside and near schools or in buildings, indicating that at these frequencies the drop is related to the drastic reduction of human activity in these edifices. In the lower-frequency range (2–8 and 4–14 Hz) the variability of the noise reduction among the stations is lower than in the high-frequency range, corresponding to about 35 % on average. This drop is due to reduced traffic during the lockdown, as most of the stations showing such changes in seismic noise in these bands are located within cities and near main or side streets. In addition to the noise reduction observed at stations located in populated areas, we also found seismic noise lockdown-related changes at several stations located far from urban areas, with movement of people in the vicinity of the station explaining the noise reductions.


2021 ◽  
Author(s):  
Bogdan Grecu ◽  
Felix Borleanu ◽  
Alexandru Tiganescu ◽  
Natalia Poiata ◽  
Raluca Dinescu ◽  
...  

Abstract. After the World Health Organization declared COVID-19 a pandemic in March 2019, Romania followed the example of many other countries and imposed a series of restrictive measures, including restricting people's mobility and closing social, cultural and industrial activities to prevent the spread of the disease. In this study, we analyze continuous vertical component recordings from the stations of the Romanian Seismic Network – one of the largest networks in Europe containing 148 stations – to explore in detail the seismic noise variation associated with the reduced human mobility and activity in Romania due to COVID-19. We focused our investigation on four frequency bands – 2–8 Hz, 4–14 Hz, 15–25 Hz and 25–40 Hz – and found that the largest reductions in seismic noise associated with the lockdown corresponds to the high frequency range, from 15 to 40 Hz. We found that all the stations with large reductions in seismic noise (> ~40 %) are located inside and near schools or in buildings, indicating that at these frequencies the drop is related to the drastic reduction of human activity in these edificies. In the lower frequency range (2–8 Hz and 4–14 Hz) the variability of the noise reduction among the stations is lower than in the high frequency range, and the noise level is reduced by up to 35 %. This drop is due to reduced traffic during the lockdown, as most of the stations showing such changes in seismic noise in these bands are located within cities, near main or side streets. In addition to the noise reduction observed at stations located in populated areas, we also found seismic noise lockdown-related changes at several stations located far from urban areas, with movement of people in the vicinity of the station explaining the noise reductions. Apart from the opportunity to investigate in more detail the seismic noise characteristics due to human mobility and activity, we show that noise reduction during the lockdown has also improved the earthquake detection capability of the accelerometers located in noisy urban environments.


RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 13733-13741 ◽  
Author(s):  
Cancan Zhang ◽  
Zhen Zhen ◽  
Liyan Ma ◽  
Kongshuang Zhao

Two nonaqueous ionic liquid (IL) microemulsions (toluene/TX-100/[bmim][PF6] and [bmim][BF4]/TX-100/benzene) were studied by dielectric spectroscopy covering a wide frequency range (40 Hz to 110 MHz).


2001 ◽  
Vol 1 (1/2) ◽  
pp. 3-7 ◽  
Author(s):  
S. Uyeda ◽  
T. Nagao ◽  
K. Hattori ◽  
M. Hayakawa ◽  
K. Miyaki ◽  
...  

Abstract. Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range ∆F = 0.5 – 40 Hz) and meteorological recordings, together with seismo-acoustic (∆F = 30 – 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations ( ∆F = 0.003 – 30 Hz), three-component electric potential variations ( ∆F < 1.0 Hz), and VLF transmitter’s signal perturbations ( ∆F ~ 10 – 40 kHz).


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