scholarly journals Distortion of a Toroidal Field by Convection

1958 ◽  
Vol 8 ◽  
pp. 1087-1088
Author(s):  
D. W. Allan ◽  
E. C. Bullard
Keyword(s):  
External Field ◽  
Magnetic Force ◽  
The Body ◽  
Toroidal Field ◽  
Finite Conductivity ◽  
Terrestrial Magnetism ◽  
Conducting Body ◽  
Material Forming ◽  
Lines Of Force

In a perfectly conducting body the lines of magnetic force move with the material; the total number crossing the surface in either direction is therefore constant, and cannot be changed by motions of the material forming the body. Both in terrestrial magnetism and in sunspots, large changes in the external field are observed which do involve a change in the total number of lines and cannot be explained by a mere crowding together of lines of force that already cross the surface. In these phenomena loops of field must emerge through the surface, and the theory must involve the finite conductivity of the material.

scholarly journals Magnetic behaviour of supraconducting tin spheres

1935 ◽  
Vol 151 (873) ◽  
pp. 316-333 ◽  
Author(s):  
K. Mendelssohn ◽  
J. D. Babbitt ◽  
Frederick Alexander Lindemann
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Force ◽  
Magnetic Behaviour ◽  
The Body ◽  
Whole Body ◽  
Measured Field ◽  
Lines Of Force ◽  
As If ◽  
Field Strengths

Until a year ago it was generally accepted that if a body is made supraconducting while in a magnetic field the lines of magnetic force were "frozen in," i. e ., whatever lines of force passed through the body at the time when it became supraconducting remained there afterwards, unaffected by any change in the external field, so long as the body was supraconducting. Meissner and Ochsenfeld, however, showed that this supposition was not true. They measured field strengths in the immediate neighbourhood of cylinders which had been cooled to supraconductivity in an external magnetic field, and found that the field of force was then of the same nature as that to be expected in the neighbourhood of perfectly diamagnetic bodies. Thus it appeared that when a body becomes supraconducting in a magnetic field the lines of force are all pressed out of the body, and the induction inside the body falls to zero. At the same time, however, these authors report on another experiment, the result of which appears to us not entirely in accordance with the assumption that the induction in the whole body became zero. They measured the field strengths inside and outside a hollow cylinder, after it had become supraconducting in a field perpendicular to its axis, and found again that the field strength outside was as if the cylinder were almost perfectly diamagnetic, but the field inside was appreciably the same as if the cylinder were non-supraconducting. We therefore made a number of experiments, hoping to find out more exactly the nature of the phenomenon.

A case of thermal boundary-layer separation by a magnetic field

1970 ◽  
Vol 67 (3) ◽  
pp. 671-676
Author(s):  
E. R. D'sa
Keyword(s):  
Thermal Boundary Layer ◽  
Field Component ◽  
Magnetic Force ◽  
Blunt Body ◽  
Boundary Layer Separation ◽  
Angular Speed ◽  
External Flow ◽  
The Body ◽  
Force Coefficient ◽  
Diffusivity Ratio

In (1) the velocity and magnetic fields were studied in the stagnation point region of a magnetized blunt body rotating with angular speed Ω. Some familiarity with this paper is assumed here: briefly, the nose section of the body was approximated by a disc of thickness t and conductivity σ′ and a perturbation solution was derived for small values of the diffusivity ratio ε (= ν/λ) and of the magnetic force coefficient N = σB2/4ρa. B is the uniform normal field component at the upperside (z = 0) of the disc, a is the strength of the external flow, p and σ are the density and conductivity of the fluid. The other two governing parameters are ω = Ω/a and β = σ′/σL, where L = (λ/a)½.

scholarly journals XVII. Contributions to terrestrial magnetism. — No. VII

1846 ◽  
Vol 136 ◽  
pp. 237-336 ◽  
Keyword(s):  
New York ◽  
Magnetic Force ◽  
The Arctic ◽  
General View ◽  
Magnetic Survey ◽  
Terrestrial Magnetism ◽  
North American Continent ◽  
The North ◽  
Common Unit ◽  
The Moment

Containing a Magnetic Survey of a considerable portion of the North American Continent. From the moment that the fact was known, that the locality of the maximum of the magnetic Force in a hemisphere is not coincident, as was previously supposed, with the locality where the dip of the needle is 90°, researches in terrestrial magnetism assumed an interest and importance greatly exceeding that which they before pos­sessed; for it was obvious that the hypothesis which then generally prevailed regard­ing the distribution of the magnetic Force at the surface of the globe, and which had been based on a too-limited induction, was erroneous, and that even the broad out­ line of the general view of terrestrial magnetism had to be recast. The observations on which this discovery rested, (being those which I had had an opportunity of making in 1818, 1819 and 1820 within the Arctic Circle, and at New York in 1822,) were published in 1825*; they constituted, I may be permitted to say, an important feature in the views, which led the British Association in the year 1835 to request that a report should be prepared, in which the state of our knowledge in respect to the variations of the magnetic Force at different parts of the earth’s sur­face should be reviewed, and, as is customary in the reports presented to that very useful institution, that those measures should be pointed out which appeared most desirable for the advancement of this branch of science. In the maps attached to the report, the isodynamic lines on the surface of the globe were drawn simply in conformity with observations, and unmixed with hypothesis of any sort. The obser­vations collected for that purpose were not those of any particular individual or of any single nation, but embodied the results obtained by all persons who up to that period had taken part in such researches, subjected to such amount of discussion only as conveyed a knowledge of the modes of observation severally employed, and reduced the whole to a common unit.

SECULAR CHANGES OF THE MAGNETIC ELEMENTS, OTTAWA, 1500–1930

1933 ◽  
Vol 9 (1) ◽  
pp. 94-96
Author(s):  
W. H. Herbert
Keyword(s):  
Magnetic Force ◽  
Secular Changes ◽  
Terrestrial Magnetism ◽  
Permanent Change ◽  
Magnetic Elements ◽  
Made In

In this paper is presented a table of the various elements of terrestrial magnetism at Ottawa from 1500 to 1930 and explains how the values were derived from old magnetic observations made in America, and not from theory. Among other points, it shows that though the total magnetic force has been declining at Ottawa for some time, yet the total magnetic force and the magnetic elements evidently go through cycles and none have apparently suffered permanent change during the time considered.

Effects of heat and mass transfer on the peristaltic motion of Sutterby fluid in an inclined channel

2020 ◽  
Vol 16 (6) ◽  
pp. 1357-1372 ◽  
Author(s):  
Faseeha Atlas ◽  
Maryiam Javed ◽  
Naveed Imran
Keyword(s):  
Heat Transfer ◽  
Magnetic Force ◽  
Fluid Model ◽  
The Body ◽  
Content Type ◽  
Long Wavelength ◽  
Symmetric Channel ◽  
Diseased Part ◽  
Fluid Parameter ◽  
Mass And Heat Transfer

PurposeThe purpose of this paper is to study the peristaltic mechanism of Sutterby fluid in a symmetric channel with mass and heat transfer.Design/methodology/approachMass and heat transfer are investigated in the assumption of Reynolds number and the long wavelength. The velocity, temperature and concentration terms for small values of Sutterby fluid parameter are achieved.FindingsGraphical results have been introduced for various important parameters. The effects of emerging key parameters are also highlighted.Originality/valueSutterby fluid model is one that represents the high polymer aqueous solutions. It is now strongly believed that any diseased part of the body would be cured better when exposed to magnetic force when compared with a drug. Peristalsis with mass and heat transfer occurs in treatment to destroy the unwanted tissues, hemodialysis and oxygenation process, etc.

Rocking the Boat: Jonah and the New Historicism

1997 ◽  
Vol 5 (4) ◽  
pp. 364-402
Author(s):  
Yvonne Sherwood
Keyword(s):  
Body Weight ◽  
Cultural Background ◽  
The Body ◽  
New Historicism ◽  
Defining Moment ◽  
The Third ◽  
The Bible ◽  
The Moment ◽  
Critical Imagination ◽  
Lines Of Force

AbstractThis reading is about critical versions of texts and how they survive (or over-live) in the critical imagination. It looks at three readings of the book of Jonah, from 1550, 1781-2 and 1860, the first freezing the moment where Jonah is catapulted from the boat as the narrative's single defining moment, the second abstracting the image of Jonah looking out over Nineveh and snarling over God's change of mind, and the third zooming in on the body of the whale, its species, jawsize and body weight. In each case it is clear that the book of Jonah (and thus the Bible) is not hermetically sealed off from culture nor merely read against a cultural background, but that the "Bible" and "Society," text and context, are held in complex and reciprocal lines of force. The story of Jonah, the whale, God and the Ninevites is a stage where the transformed fears and anxieties of cultures are acted out, and gives back to society a transformed, idealised, picture of itself.

scholarly journals Increasing the operating depth of an autonomous underwater vehicle using an intelligent magnetic field

2021 ◽  
Vol 10 (3) ◽  
pp. 207
Author(s):  
Ali Jebelli ◽  
Arezoo Mahabadi ◽  
Mustapha C. E. Yagoub
Keyword(s):  
Magnetic Force ◽  
Autonomous Underwater Vehicle ◽  
Autonomous Underwater Vehicles ◽  
The Body ◽  
Body Structure ◽  
Frictional Drag ◽  
High Mechanical Strength ◽  
Robot Performance ◽  
Design And Manufacture ◽  
Robot Body

<p>Designing and manufacturing a suitable body is one of the most effective factors in increasing the efficiency of autonomous underwater vehicles (AUVs). In fact, increasing the propulsive power of an AUV by reducing the frictional drag on its body and incre asing its maneuverability will positively affect key parts of the AUV’s hardware and software such as control system, sensors, AUV vision, batteries and thrusters. On the other hand, a suitable body should have features such as lightness, underwater vehicl e’s balance, high mechanical strength, and enough space for equipment. Therefore, the design and manufacture of the body requires a lot of analysis in terms of body material, aerodynamic calculations, etc., increases the overall cost. This paper aims to re duce the stress in the body of a Polytetrafluoroethylene ( PTFE ) underwater robot and to increase its operating depth without changing the body’s structure by using fuzzy logic to intelligently controlling the magnetic force generated by the repulsion betwe en the coil and the cylindrical magnet, which saves energy, reduces battery consumption, and increases system performance. The results show that the robot performance depth increases by more than 50% without changing the robot body structure.</p>

scholarly journals Contributions to terrestrial magnetism, No. 2

1843 ◽  
Vol 4 ◽  
pp. 287-289
Keyword(s):  
Magnetic Force ◽  
Volcanic Rocks ◽  
Mean Value ◽  
Full Detail ◽  
Terrestrial Magnetism ◽  
Independent Determination ◽  
Magnetic Elements ◽  
Future Improvement ◽  
Made In

This paper is the second of a series, in which the author purposes to communicate to the Royal Society the results of magnetic observations in different parts of the globe, having for their object to supply the requisite data for deducing the numerical elements corresponding to the present epoch of the general theory of terrestrial magnetism. It consists of two sections; the first comprises the observations of Captain Belcher, R. N., and the officers of H. M. S. Sulphur, at twenty-nine stations on the west coast of America, and the adjacent islands, between the latitudes of 60° 21' N. and 18° 05' S, The second contains a new determination, by the same officers, of the magnetic elements at Otaheite, made in consequence of the discrepancies in the results obtained by previous observers, and of a note in M. Gauss’s Allgemeine Theorie, in which Otaheite is spoken of as a highly important station for the future improvement of the calculations of the theory. Abstracts are given of the original observations which are deposited in the Hydrographic Office of the Admiralty, as well as a full detail of the processes of reduction by which their results have been computed. The values of the horizontal and total intensities are expressed in terms by which the results of observation are immediately comparable with the maps of MM. Gauss and Weber in the “Atlas des Erdmagnetismus.” By an investigation into the “probable error” of a single independent determination of the magnetic intensity with Hansteen’s apparatus, derived from the data furnished by Captain Belcher’s observations, the author shows the extreme improbability that the differences in the results obtained at Otaheite by Messrs. Erman, FitzRoy and Belcher, should be occasioned by instrumental or observational error. They are also far greater than can, with any degree of probability, be ascribed to periodical or accidental variations in the magnetic force from its mean value. The only known cause adequate to their explanation is what may with propriety be termed Station error ; that is, local disturbing influences, in an island composed chiefly of volcanic rocks, and where the spot of observation selected by the different observers may not have been precisely the same.

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