Contact flexible microstrip applicators (CFMA) in a range from microwaves up to short waves

The present paper continues the account of wireless investigations of the ionized regions of the upper atmosphere given in two previous papers. The results discussed in it consist chiefly of measurements of the equivalent heights of the ionized regions made simultaneously at two or three receiving stations with wave-lengths of the order of 100 metres. The frequency-change method of measuring the equivalent height was used throughout. 2. Extension of Equivalent Height Measurements to the Use of Short Waves . The experiments described previously were continued with shorter wave-lengths with two objects in view. In the first place it had been found that 400-metre waves penetrated the lower ionized region (E region) only on certain nights, and then only during the few hours before dawn. This result clearly showed that penetration of this region was most likely when the density of ionization was least. But, according to most theories of wireless propagation, a greater electronic density is required to reflect or refract short waves than is the case with long waves, so that it was anticipated that by reducing the wave-length below 400 metres it might be possible to penetrate E region over a longer period of time during the night than had been possible when 400-metre waves had been used. In this way it was hoped to make a more detailed study of the variation of the equivalent height of the upper region (F region) which had been found to reflect 400-metre waves on the occasion when they had penetrated the normal E region. Secondly, since it is known that the attenuation of the ground waves increases rapidly as the wave-length is reduced below, say, 400 metres, it was expected that, with the use of shorter waves, the ratio of the values of downcoming wave intensity and ground wave intensity would be much increased at all stations. Such an increase, it was expected, would make it possible to continue the measurements of equivalent heights, in general, a good deal further into the daylight hours. Such daylight measurements on longer waves had previously been found difficult, because of the relative weakness of the intensity of the downcoming waves as compared with that of the ground waves.

Download Full-text

Drop-impact hydrodynamics: Short waves on a surface of the crown

Doklady Physics ◽

10.1134/s1028335813070021 ◽

2013 ◽

Vol 58 (7) ◽

pp. 296-300 ◽

Cited By ~ 11

Author(s):

Yu. D. Chashechkin ◽

V. E. Prokhorov

Keyword(s):

Drop Impact ◽

Short Waves

Download Full-text

EROSION AROUND A PILE DUE TO CURRENT AND BREAKING WAVES

Coastal Engineering Proceedings ◽

10.9753/icce.v21.102 ◽

1988 ◽

Vol 1 (21) ◽

pp. 102 ◽

Cited By ~ 2

Author(s):

E.W. Bijker ◽

C.A. De Bruyn

Keyword(s):

Shear Stress ◽

Breaking Waves ◽

Velocity Profiles ◽

Long Waves ◽

Orbital Velocity ◽

Bottom Shear Stress ◽

Normal Waves ◽

Short Waves ◽

A Current

Tests have been performed on a vertical pile subject to current only and to a combination of current with normal waves and current with breaking waves. The scour around the pile produced by current only is decreased by normal short waves superimposed upon that current and increased when breaking waves are superimposed upon the current. After analysis of the velocity profiles in the undisturbed area upstream of the pile and next to the pile, the following explanation is found for this phenomenon. When normal short waves are superimposed upon a current, the bottom shear stress of the combination of current with waves is increased more in the undisturbed area than next to the pile in the scour area. This results in a decrease of the scour around the pile. Due to the large values of the orbital velocity under breaking waves this effect is reversed for the combination of a current with breaking and relatively long waves. This results in an increase of the scour around the pile.

Download Full-text

📚 og 📞 - En 😍 📖

Passage - Tidsskrift for litteratur og kritik ◽

10.7146/pas.v29i72.19771 ◽

2014 ◽

Vol 29 (72) ◽

Author(s):

Lone Koefoed Hansen

Keyword(s):

Social Media ◽

Short Waves

Lone Koefoed Hansen: “📚 and 📞: A 😍 📖”Reflecting on the intersections of literature and the smartphone language emoji, the essay discusses a range of contemporary examples of emoji literature as well as recent appropriations or translations of literature to emoji, often happening in spontaneous and short waves on social media.

Download Full-text