Effects of pulse voltage rising edge on discharge evolution of He APPJ in dielectric tube

We have studied the interactions of Ba ion with K channels. Ba2+ blocks these channels when applied either internally or externally in millimolar concentrations. Periodic depolarizations enhance block with internal Ba2+, but diminish the block caused by external Ba2+. At rest, dissociation of Ba2+ from blocked channels is very slow, as ascertained by infrequent test pulses applied after washing Ba2+ form either inside or outside. The time constant for recovery from internal and external Ba2+ is the same. Frequent pulsing greatly shortens recovery time constant after washing away both Ba2+in and Ba2+out. Block by Ba2+ applied internally or externally is voltage dependent. Internal Ba2+ block behaves like a one-step reaction governed by a dissociation constant (Kd) that decreases e-fold/12 mV increase of pulse voltage: block deepens with more positive pulse voltage. For external Ba2+, Kd decreases e-fold/18 mV as holding potential is made more negative: block deepens with increasing negativity. Millimolar external concentrations of some cations can either lessen (K+) or enhance (NH+4, Cs+) block by external Ba2+. NH+4 apparently enhances block by slowing exist of Ba ions from the channels. Rb+ and Cs+ also slow clearing of Ba ions from channels. We think that (a) internally applied Ba2+ moves all the way through the channels, entering only when activation gates are open; (b) externally applied Ba2+ moves two-thirds of the way in, entering predominantly when activation gates are closed; (c) at a given voltage, Ba2+ occupies the same position in the channels whether it entered from inside or outside.

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Lightning protection of the object located on the slope

Herald of the Ural State University of Railway Transport ◽

10.20291/2079-0392-2021-1-93-103 ◽

2021 ◽

pp. 93-103

Author(s):

A. A. Kosyakov ◽

Keyword(s):

Pulse Voltage ◽

Lightning Protection ◽

Engineering Practice ◽

Protection Device ◽

Lightning Strikes ◽

Protection Zones ◽

Pulse Voltage Generator ◽

Voltage Generator ◽

Protected Object

The article points out the drawback of all the current instructions for the lightning protection device: the lack of instructions for calculating the lightning protection zones of an object located on a slope. The methods of applying the current instructions for the lightning protection device when placing an object on a slope are given, based on the assumption that lightning strikes the lightning rods vertically and perpendicular to the slope. The features of the choice of lightning protection characteristics (calculated points of the protected object, calculated heights of lightning rods, methods of constructing lightning protection zones) are described. A method for calculating the lightning protection zones of an object located on a slope is proposed, based on the assumption that lightning strikes lightning rods perpendicular to the slope, in particular, the concept of the axis of a conditional lightning rod shifted on the object plan for calculating lightning protection zones is introduced. The consequences of the application in engineering practice of the methodology for calculating the lightning protection zones of an object located on a slope, based on the assumption that lightning strikes the lightning rods perpendicular to the slope, are indicated. Using a pulse voltage generator, tests were performed on a model of a lightning rod located on a slope in order to determine the direction of lightning strikes-vertical or perpendicular to the slope. It was determined experimentally that the proposed method for calculating the lightning protection zones of an object located on a slope, based on the assumption that lightning strikes lightning rods perpendicular to the slope, should be used in cases where the protected objects are located on slopes with an angle of more than 25°.

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