Section Of Arc Research Articles

EVEREST SPHEROID IN METRES

AbstractThe parameters of the Everest spheroid were obtained by George Everest by an arc-measuring method. In this method, sections of meridional arcs are measured by triangulation. Astronomical observations are made at selected points along the arc between the terminals. The differences between geodetic and astronomical latitudes are found out on a preliminary reference spheroid. The position of the arcs on the preliminary reference spheroid and the parameters of the spheroid are then changed to minimise the differences between geodetic and astronomic latitudes. Each separate arc gives a separate solution. Several arc measurements are then combined to give a common spheroid. Everest deduced the parameters of his spheroid from consideration of the arcs Punnae–Kalianpur and Greenwich–Formentera.

Experimental and theoretical study of a stationary high-current arc in a supersonic nozzle flow

In a previous paper (Hermann et al 1974) a detailed experimental and theoretical investigation of an arc in a supersonic nozzle flow was initiated by discussing the high-pressure arc section near the stagnation point.This paper is a continuation of this work for the section further downstream, especially within the nozzle. Extensive measurements of temperature, flow velocity, pressure and electric field strength are described. Theoretical results are obtained by a two-zone model.A detailed comparison between theory and experiment allows for the first time a complete quantitative discussion of all effects influencing the arc and the flow. Compared with the arc in the high-pressure section the influence of radiative energy transfer decreases. Instead, flow turbulence becomes the dominating exchange mechanism.

Archean Quench-Texture Tholeiites

Tholeiitic metabasalts and metaandesites from sub-greenschist metavolcanics in the Abitibi volcanic belt northeast of Noranda–Rouyn display delicate and ornamental crystals indicative of rapid or supercooling. These textures compare directly with those observed in modern sea-floor basalts. The textural and chemical data suggest that these Archean rocks may represent a complete (?) section of an island arc, from the deeper stratigraphic levels (mostly monotonous tholeiites) to the more typical island-arc superstructure with intermingled calcalkaline and tholeiitic series. The deeper section can only be a relic of ancient oceanic lithosphere if the Archean sea floor had a wider range in chemistry than the modern-day equivalent.

A theoretical and experimental investigation of the parameters for an electric arc

A new method is presented for the determination of the temperature distribution over the cross section of a cylindrical arc, as well as of the volt-ampere characteristics, and these are compared with experimental data.

Cross-Section Deformation Effects in the Vibration of Thin-Walled Beams of Arc Section

Differential equations describing the coupling of ordinary bending motion with cross-sectional distortion are obtained for thin-walled beams of circular-arc cross-section using Hamilton's principle. In deriving the theory the cross-sectional deformation is assumed to take the form of the characteristic functions of a curved beam of the shape of the section. The variation with wavelength of the frequency spectra which result from the coupling is obtained. Experimental results showing the effects of the variation of the parameters of the beam geometry on the natural frequencies are in reasonable agreement with the theory.

Fundamental Research on the Cold-Roll Forming of Metal Strips

The experimental and the theoretical researchs were performed on the cold-roll forming of metal strips to the cross section of circular arc through a set of the upper roll and the lower. From the experiment, it was found that the membraneous strain in the strip was negligibly small as compared with the bending strain. Therefore, the cold-roll forming was treated as a biaxial bending problem. The roll force and torque were analyzed by means of the strain energy method. The theoretical results were in good agreement with the experimental results.

Analysis of Interoceptive Reflexes in Experimental Tuberculosis

It was shown that in its common effect upon healthy cats, tuberculin first of all inhibits reflexes arising from the chemoreceptors. This effect was most marked in perfusion experiments on the intestine, as well as in experiments with the carotid sinus reflex. Inhibition of reflexes from mechanoreceptors of the urinary bladder was less marked. The assumption is made that in its general effect, tuberculin inhibits the central neural elements of the afferent section of the reflex arc associated with tissue chemoreceptors.

The Centre of Shear for Sections Bounded by Two Circular Arcs

In two recent notes Jacobs and Duncan considered the St. Venant torsion and flexure problems for beams of aerofoil cross section and have given methods for determining the centre of shear once the torsion function for the section has been found. The purpose of the present note is to give results for the location of the centre of shear for a limited range of cross sections bounded by two circular arcs for which the torsion function has long been known. The calculations shed some light on the relative influence of camber and thickness on the location of the centre of shear and are compared with the well known results for thin circular arc sections illustrated in the Structural Data Sheet 00.06.04.

Photographic Study of A-C Arcs in Flowing Liquids

I. Introduction THE importance of fluid flow in aiding arc extinction in circuit interrupters has long been known. Two general types of explanation of the large effect found have been offered. Slepian1,2,3 who seems to have been the first to stress the importance of the motion of the gases liberated by the arc from the surrounding oil or solid insulation in oil breakers and expulsion fuses, sought the explanation in reduced arc section at current zero, and increased diffusion rate of ions and molecules arising from the turbulence. Other investigators have expressed similar views, at least in part.4,5

Torsional Stability of Cylindrical Shells

T design of thin-walled cylindrical shells carrying compressive loads can be greatly simplified by means of diagrams of ellipse of critical stress. For a given form of cross-section and material, only one diagram is necessary. The average critical stress has an elliptical relation to certain dimensionless parameters of the geometry of the shell. Economical shells should have high torsional rigidity. Examples of the design of equal-legged angles and circular arc sections are here given, together with some of the experimental results.

III. Rectification of logarithmic errors in the measurements of two sections of the meridional arc of India. In a letter to Professor Stokes, Sec. R. S. By Colonel Everest, F. R. S

It will be in your recollection, that some years ago, at the request of the Court of Directors of the East India Company, I compiled from the General Report of the Great Trigonometrical Survey of India, a work entitled “An Account of the Measurement of two Sections of the Meridional Arc of India,” executed by myself and my assistants, an impression of which (printed in 1847) was presented to the Royal Society. In reference to the work in question, I now have to mention that in the computation of the meridional triangles ( vide pp. 240 to 248) there have been some errors committed in taking out the logarithms of the twelfth triangle (p. 241) and the twentieth triangle (p. 243); and as from the nature of that series, the purpose of which is to project the sides of the principal triangles on the meridian, any such error must run through all the computations subsequent to it, I have had the whole series recomputed, and now forward for submission to the Royal Society, a sheet containing a revised synopsis ( vide p. 248), such as it would have been, but for the errors adverted to, to which it is my wish that the utmost publicity should be given.