Surge Type Research Articles

Basal Hot Spot on a Surge Type Glacier

DEEP temperature measurements of ice on the Fox Glacier, Yukon, indicate a zone of basal ice at the pressure melting point and the discovery of this temperate basal ice supports surge theories which require basal melting.

Lightning protection of cable-connected high-voltage distribution substations by surge diverters

For devising a general guidline on lightning protecting of distribution substations connected to overhead lines through cables, the surge voltages at both ends of the cable are derived for various types of incident lightning surges. The substation is represented by an open-circuited cable, which would result in surge voltages at the cable terminations equal to, or more severe than, the surge voltages for practical installations. The results are used to assess:(i) whether protective devices are needed(ii) when they are needed, whether surge diverters at one end of the cable provide adequate protection.Attention is paid to the surge strength of the line insulation, as on it depend the types of incident lightning surge to be used in devising general guidelines.

A two-dimensional numerical sea model

The model has, in the first place, been developed for the detailed investigation of various types of North Sea storm surge, particularly the external surge. As in some earlier investigations the linearized hydrodynamical equations are solved numerically by using a finite-difference grid and a step-by-step procedure in time. However, a special feature of the present approach is that, within the basic grid system, it is possible to choose a general form of sea boundary: the computations are then carried out accordingly, on a digital computer, using an Algol program . In this sense the aim has been to develop a numerical tool of fairly wide application for the study of surge and tidal phenomena in adjacent seas. For the North Sea, surges experienced at several ports around the shores of the Sea have been compared with those derived numerically. Also, contour lines of sea-level disturbance have been drawn showing patterns of surge development. Perhaps for the first time, the continental shelf sea surrounding the British Isles has been treated as a single dynamical unit, and the influence of flow through the Strait of Dover on surge levels in the North Sea has been studied. The work has laid out guide lines for future research involving the application of numerical models to problems of storm surges and tides in British waters. A first step has been taken towards the establishment of a surge forecasting system for the east coast o f England based on dynamical principles.

Some terrestrial effects of flares and surge type filaments

Тщательное рассмотрение крупного наблюдательного материала касающегося активной области из 5 мая 1958 г. указывает на тесную физическую связь между волокнами типа “surge” и вспышкой, которую они сопровождают. Во время появления “surge” повышается аномальная рентгеновская змиссия, излуаемая вспышкой. Зто аномальное коротковолновое излучение появляется и во время возниковения протуберанцев типа “surge” на лимбе солнечного диска. Зто показывает, что такая рентгеновская змиссия сопровождающая вспышки и волокна типа “surge” вероятнее всего возникает в той области короны, которая участвует в комплексном продессе вспышки.

The active region on the west solar limb during the eclipse of 25 February 1952.

view Abstract Citations (3) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The active region on the west solar limb during the eclipse of 25 February 1952. Athay, R. G. ; Evans, J. W. ; Roberts, W. O. Abstract At the Khartoum eclipse there was an active region at io0S latitude on the west limb. This region was first observed as a small sunspot group and plage area near the east limb on 12 February. One flare was reported in this region on 13 February, one on i6 February, two on 24 February and two on 25 February."2 The west limb spectrograms of the chromospheric flash obtained by the High Altitude Observatory showed a small region of enhanced emission and immediately adjacent to it a small region of greatly reduced emission. Moon profile pictures taken at Khartoum showed that the observed effects could not be attributed to irregularities in the moon's profile. A few degrees away from these regions there was a bright prominence that appeared to be of a surge type. The region of reduced emission showed mainly in the chromospheric lines. There was also an apparent decrease in the coronal line intensities in the lowest levels of the corona, but there was no marked decrease in the continuum intensity. The decrease in the line intensities apparently resulted from either a cloud of absorbing matter or an actual decrease in chromospheric emission. The region of enhanced emission showed a maximum in the continuum and all chromospheric and coronal line intensities. The greatest increase in chromospheric lines was in He+, X4686. The yellow coronal line, X5694, showed in this region on our spectrograms. It did not show at any other positions, and to our knowledge has not been observed at previous eclipses. Lyot and Doilfus have also reported this coronal line and four new coronal lines from observations at Khartoum.3 All of these lines were found in this region of enhanced emission. The intensities of all of the chromospheric lines decreased much more slowly with height in this region than in an east limb region previously analyzed,4 which seemed to represent the undisturbed chromosphere. It was suggested that the region of enhanced emission was caused by a limb flare. A preliminary interpretation of the data from this region showed that both the electron density and kinetic temperature were greater than in the east limb region, and that the temperature increased less rapidly with height. A more detailed analysis of this region will be published elsewhere. This work was supported by the Office of Naval Research and carried out in cooperation with the Naval Research Laboratory. Publication: The Astronomical Journal Pub Date: June 1954 DOI: 10.1086/106983 Bibcode: 1954AJ.....59..182A full text sources ADS |

A THEORY OF NORTH SEA SURGES

The analysis of a large number of observations of North Sea surges by R. H. Corkan has enabled him to make a classification of them into types. One type of surge appears to be due to the passage of an atmospheric depression over the entrance to the North Sea. By simplifying the mathematical conditions it is possible to predict the results of the passage of such a depression. These are largely in conformity with the observations. In particular it is shown that the surge produced is a progressive one, passing from the entrance to the North Sea to the closed end and increasing uniformly in amplitude.

Mechanical demonstrator of traveling waves

By means of the device described in this article, which simulates in a mechanical sense the electrical phenomena of traveling waves on power-transmission lines, various types of surges may be visualized and relations fundamental in transmission theory may be deduced.

Characteristics of the new station-type autovalve lightning arrester

THIS PAPER is a description of the characteristics of a new line of station-type autovalve arresters. These arresters are designed to limit the surge voltage to a low value for all types of surges, and at the same time to have high enough 60-cycle breakdown and cut off characteristics to be practically free from trouble due to transient 60-cycle overvoltages.