Showing papers by "National Technical University of Athens published in 1969"
TL;DR: In this paper, a new method for the determination of the compressive strength of rock σ c in situ or in test blocks has been developed based on the relationship U 0 = k 0. (P − P 0 ) obtained in drilling a rock by a diamond drill, where U 0 is the penetration rate of the rock per revolution of the bit at the instant of commencing drilling; P is the drilling thrust and P 0 and k 0 are constants.
15 citations
01 Feb 1969
TL;DR: In this paper, the authors describe the behavior of a rod-rod gap of 120cm under impulse voltages of a front duration of 2μs and a tail duration of 1000μs.
Abstract: This paper describes the behaviour of a rod-rod gap of 120cm under impulse voltages of a front duration of 2μs and a tail of 1000μs. The results were obtained mainly by measuring the field at the electrode surface by a method which permitted simultaneous recordings at both ends of the gap. Photographs were taken of the discharge in the gap using a still camera with an f0.95 lens. The discharges at both electrodes have been studied and various observations made about the mechanisms that lead to the breakdown of the gap, in particular the influence of space charges in the gap.
2 citations