scholarly journals Comparison of Mechanical and Low-Frequency Dielectric Properties of Thermally and Thermo-Mechanically Aged Low Voltage CSPE/XLPE Nuclear Power Plant Cables

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2728
Author(s):  
Ramy S. A. Afia ◽  
Ehtasham Mustafa ◽  
Zoltán Ádám Tamus
Keyword(s):  
Dielectric Properties ◽  
Mechanical Stress ◽  
Nuclear Power ◽  
Low Voltage ◽  
Low Frequency ◽  
Polymeric Materials ◽  
Central Frequency ◽  
Clear Trend ◽  
Service Period ◽  
Aging Factors

During the service period of low-voltage nuclear cables, multiple stresses influence the aging of polymeric materials of cables. Thermal and radiation stresses are considered service aging factors in qualification tests, while the standards usually do not prescribe mechanical stress. CSPE/XLPE insulated nuclear cable samples were exposed to thermal and combined thermo-mechanical aging for more than 1200 h at 120 °C. The real and imaginary parts of permittivity were measured in the 200 μHz to 50 mHz range as dielectric properties. The Shore D hardness of the samples was measured to analyze the mechanical characteristics of the cable. To characterize the dielectric spectrum, derived quantities, namely central real and imaginary permittivities and real and imaginary permittivities’ central frequencies were calculated. The change of dielectric spectra did not show a clear trend with aging, but the imaginary permittivity’s central frequency was higher by 0.5 mHz in the case of thermo-mechanically aged samples. The Shore D hardness was also higher on the thermo-mechanically aged samples. These findings show the combined aging has a higher impact on the insulation properties. Hence, involving the mechanical stress in the aging procedure of cable qualification enables the design of more robust cables in a harsh environment.

A review of high-power magnetoplasmodynamic electric propulsion designs and studies of RSC Energia

2020 ◽  
pp. 112-133
Author(s):  
Victor V. SINYAVSKIY
Keyword(s):  
Service Life ◽  
Electric Power ◽  
High Power ◽  
Electric Propulsion ◽  
Nuclear Power ◽  
Materials Science ◽  
Low Voltage ◽  
Power Input ◽  
Design Bureau ◽  
Rocket Propulsion

At the initiative of S.P.Korolev, in 1959, Special Design Bureau No.1 (now RSC Energia) established the High-temperature Power Engineering and Electric Propulsion Center which was tasked with development of nuclear electric propulsion for heavy interplanetary vehicles. Selected as the source of electric power was a nuclear power unit based on a thermionic converter reactor, and selected as the engine was a stationary low-voltage magnetoplasmodynamic (MPD) high-power (0.5–1.0 MW) thruster which had thousands of hours of service life. The paper presents the results of extensive efforts in research, development, design, materials science experiments, and tests on the MPD-thruster, including the results of development and 500-hours life tests of an MPD-thruster with a 500-600 kW electric power input that used lithium propellant. The world’s first lithium 17 kW MPD-thruster was built and successfully tested in space. The paper points out that to this day nobody has surpassed the then achievements of RSC Energia neither in thruster output during long steady-state operation, nor in performance and service life. Key words: Martian expeditionary vehicle, nuclear electric rocket propulsion system, electric rocket thruster, magnetoplasmodynamic thruster, lithium, cathode, anode, barium, electric propulsion tests in space.

Fault Detection for Low-Voltage Residential Distribution Systems With Low-Frequency Measured Data

2020 ◽  
Vol 14 (4) ◽  
pp. 5265-5273
Author(s):  
Mehdi Shafiei ◽  
Faranak Golestaneh ◽  
Gerard Ledwich ◽  
Ghavameddin Nourbakhsh ◽  
Hoay Beng Gooi ◽  
...  
Keyword(s):  
Fault Detection ◽  
Distribution Systems ◽  
Low Voltage ◽  
Low Frequency ◽  
Measured Data ◽  
Residential Distribution

Low voltage and low frequency current mirror using a two-MOS subthreshold OP-Amp

1996 ◽  
Vol 32 (7) ◽  
pp. 605 ◽  
Author(s):  
K. Tanno ◽  
O. Ishizuka ◽  
Z. Tang
Keyword(s):  
Low Voltage ◽  
Low Frequency ◽  
Current Mirror ◽  
Op Amp ◽  
Frequency Current

Low-Frequency Dielectric Properties of Acenaphtene

1993 ◽  
Vol 229 (1) ◽  
pp. 221-223
Author(s):  
B. Kucharska ◽  
J. Michalski ◽  
A. Szymaǹski ◽  
J. [sgrave]viatek
Keyword(s):  
Dielectric Properties ◽  
Low Frequency

scholarly journals Novel neuronal and astrocytic mechanisms in thalamocortical loop dynamics

2002 ◽  
Vol 357 (1428) ◽  
pp. 1675-1693 ◽  
Author(s):  
Vincenzo Crunelli ◽  
Kate L. Blethyn ◽  
David W. Cope ◽  
Stuart W. Hughes ◽  
H. Rheinallt Parri ◽  
...  
Keyword(s):  
Low Voltage ◽  
Electrical Coupling ◽  
Low Frequency ◽  
Network Activity ◽  
Thalamic Neuron ◽  
Cellular Mechanisms ◽  
Brain Areas ◽  
Sensory Stimuli ◽  
Loop Dynamics ◽  
Intracellular Ca

In this review, we summarize three sets of findings that have recently been observed in thalamic astrocytes and neurons, and discuss their significance for thalamocortical loop dynamics. (i) A physiologically relevant ‘window’ component of the low–voltage–activated, T–type Ca 2+ current ( I Twindow ) plays an essential part in the slow (less than 1 Hz) sleep oscillation in adult thalamocortical (TC) neurons, indicating that the expression of this fundamental sleep rhythm in these neurons is not a simple reflection of cortical network activity. It is also likely that I Twindow underlies one of the cellular mechanisms enabling TC neurons to produce burst firing in response to novel sensory stimuli. (ii) Both electrophysiological and dye–injection experiments support the existence of gap junction–mediated coupling among young and adult TC neurons. This finding indicates that electrical coupling–mediated synchronization might be implicated in the high and low frequency oscillatory activities expressed by this type of thalamic neuron. (iii) Spontaneous intracellular Ca 2+ ([Ca 2+ ] i ) waves propagating among thalamic astrocytes are able to elicit large and long–lasting N –methyl–D–aspartate–mediated currents in TC neurons. The peculiar developmental profile within the first two postnatal weeks of these astrocytic [Ca 2+ ] i transients and the selective activation of these glutamate receptors point to a role for this astrocyte–to–neuron signalling mechanism in the topographic wiring of the thalamocortical loop. As some of these novel cellular and intracellular properties are not restricted to thalamic astrocytes and neurons, their significance may well apply to (patho)physiological functions of glial and neuronal elements in other brain areas.

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