scholarly journals Experimental researches in voltaic electricity

1837 ◽  
Vol 3 ◽  
pp. 98-101
Keyword(s):  
Copper Wire ◽  
Electric Circuit ◽  
Dissimilar Metals ◽  
Square Root ◽  
Liquid Part ◽  
Magnetic Action ◽  
Electro Magnetic ◽  
Different Diameters ◽  
Experimental Researches ◽  
Dilute Nitric Acid

The author adduces many facts in refutation of the theory by which Volta endeavoured to explain the development of electricity in galvanic circles. He shows that the contact of dissimilar metals is not necessary for producing that effect, for galvanic action may be obtained by employing only one metal, if the two ends of the same copper wire be coiled into helices of different diameters, and immersed into dilute nitric acid. The experiments of Mr. Parrot of St. Petersburgh are cited as leading to results totally different to those on which Volta rested the foundations of this theory. The author points out several important marks of distinction between voltaic and common electricity, and denies that the latter is capable of passing into the former. He shows by an experiment that the free electricity developed by heat is independent of that developed by galvanic action. Chemical decompositions are effected in a totally different manner by voltaic and by ordinary electricity; for in the former case the two elements of the decomposed substance are found disengaged at the opposite poles, but in the latter they are developed at the same point, and appear more as the effect of a cleavage of the molecules by the mechanical agency of electricity. The author conceives that in a galvanic circle of zinc and copper with interposed water, the superior attraction of the zinc for oxygen produces an arrangement of the molecules of the water such that the particles of oxygen entering into the composition of each are all turned towards the zinc. This definite arrangement produces in its turn, by production on the neutral electric fluid contained in the metal, a corresponding definite arrangement of the two electricities along the whole electric circuit. Hence electro-magnetic effects may be obtained without any chemical decomposition; this latter effect taking place only when the attraction of the metal for one of the elements of the fluid is greater than that between the two elements of the fluid: and upon this principle the author conceives that the phænomena of the secondary piles of Ritter, and those observed by M. de la Rive, may be explained. By adopting the theory of the successive decomposition and recomposition of each particle of fluid in the line of action, we avoid the necessity of supposing the transference of the disengaged element through the intervening mass of fluid. Whatever circumstance favours the decomposition of the water, will also increase the power of the voltaic arrangement. Conformably to these views we find that all liquids whose component parts go to the same pole are non-conductors of voltaic electricity. A given section of a liquid is capable of conducting only a limited quantity of electric influence. It was also found by experiment that when sulphuric acid was employed, the quantity of electro-magnetic action in the connecting wire is exactly proportional to the quantity of water decomposed in the liquid part of the circuit. This quantity is, within certain limits, inversely proportional to the square root of the distance between the plates.

XIII. Introductory research on the Induction of magnetism by electrical currents

1856 ◽  
Vol 146 ◽  
pp. 287-295
Keyword(s):  
Copper Wire ◽  
The Other ◽  
Electrical Currents ◽  
Molecular Changes ◽  
General Law ◽  
Linear Dimensions ◽  
The Subject ◽  
Different Dimensions ◽  
Different Diameters ◽  
Experimental Researches

The researches of Jacobi and Lenz led them some years ago to the announcement as a law, that when two bars of iron of different diameters but equal to one another in length and surrounded with coils of wire of the same length carry equal streams of electricity, the magnetism developed in the bars is proportional to their respective diameters. Experiments which I made about the same time threw doubts on my mind as to the general accuracy of the above proposition, for I found that the magnetism induced in straight bars of a variety of dimensions varying from ⅓ to 1 inch in diameter, and from 7 inches to one yard in length, was nearly proportional to the length of the wire and the intensity of the current it conveyed, irrespectively of the shape or magnitude of the bars. The valuable experimental researches which have recently been made by Weber, Robinson, Müller, Dub and others, refer chiefly to the attraction of the keeper or submagnet, and are not calculated to confirm or disprove either of the above propositions; and the correct view is probably that of Professor Thomson, who considers both of them as corollaries (applying to the particular conditions under which the experiments were made) of the general law, that “similar bars of different dimensions, similarly rolled with lengths of wire proportional to the squares of their linear dimensions and carrying equal currents, cause equal forces at points similarly situated with reference to them*.” I have been induced to undertake some further experiments with an endeavour to elucidate the subject, and also to open the way to the investigation of the molecular changes which occur during magnetization. I procured four iron bars one yard long and of the respective diameters and 1/6, ¼, ½ and 1 inch, their weights being 1736, 3802, 14560, and 55060 grs. Each bar was wound with 56 feet of copper wire 1/40th of an inch in diameter covered with silk, the number of convolutions being 1020, 712, 388, and 207 respectively. The smallest bar was closely covered throughout its entire length, but on account of the larger surface of the other bars the coils had to be distributed upon them as evenly as possible. Four other bars were also procured of the same diameters as the above. They were however twice as long, weighing 3500, 7624, 29944, and 108574 grs., and were wrapped with double the length of wire, forming 2060, 1435, 768, and 418 convolutions respectively.

scholarly journals XII. A new current weigher and a determination of the electromotive force of the normal Weston cadmium cell

1908 ◽  
Vol 207 (413-426) ◽  
pp. 463-544 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic System ◽  
Electric Circuit ◽  
Secular Variations ◽  
System Of Units ◽  
Electro Magnetic ◽  
The Magnetic Field ◽  
A Current ◽  
Mutual Action

A Current can be measured absolutely in the electro-magnetic system of units either by means of the action of the current on a magnet, or of the current on a current. The former method has the disadvantage that at least two independent measurements are necessary. For example, in using an electro-magnetic balance, the strength of the magnet acted on by the electric circuit has to be determined, as well as the force exerted on the magnet by the circuit. In galvanometers, either of the sine or tangent type, the magnetic field produced by the electric circuit is compared with the earth’s horizontal field, the strength of which is determined independently. Further, as the strength of artificial magnets cannot be regarded as truly constant, and the earth’s field is subject to diurnal and secular variations, this class of measurement is not ideal. In the electrodynamic class of measurement the mutual action between two or more coils carrying current takes the form of a torque, as in electrodynamometers, or a direct force, as in current weighers. In electrodynamometers the torque may be measured with a bifilar suspension, the torsion of a wire or spring, or by means of a gravity balance. Current weigher measurements are almost always made by direct comparison with gravity, which is believed to be constant, and is known to a higher degree of accuracy than the strengths of any magnet or magnetic field that has yet been measured.

scholarly journals Experimental researches in electricity

1837 ◽  
Vol 3 ◽  
pp. 91-93
Keyword(s):  
Electric Current ◽  
Copper Wire ◽  
The Other ◽  
Great Length ◽  
Electrical Currents ◽  
Electric Current Passing ◽  
Electrical Condition ◽  
The Moment ◽  
Electrical Induction ◽  
Experimental Researches

This paper is divided into four parts: the first being on the Induction of Electric Currents; the second, on the Evolution of Electricity from Magnetism; the third, on a new Electrical Condition of Matter; and the fourth, on Arago’s Magnetic Phænomena. The author defines electrical induction to be the power which electrical currents possess of inducing any particular state upon matter in their immediate neighbourhood. A great length of copper wire, 1-20th of an inch in diameter, was wound round a cylinder of wood so as to compose two helices, the coils of which were intermixed, but prevented from touching each other by interposed threads of twine and calico. One helix was connected with a voltaic battery, and the other with a galvanometer. No effect was perceived on the latter, with a battery of 10 plates; a slight effect only with one of 100 plates; and a distinct deflection of the needle of the galvanometer occurred when the contact was made with a battery of 120 plates. While the contact was preserved, the needle returned to its natural position, and was unaffected by the electric current passing through the wire connected with the battery; but on breaking the connexion, the needle of the galvanometer was again deflected, but in a direction contrary to that of its former deflection. Hence it is inferred that the electric current sent by the battery through one wire, induced a similar current through the other wire, but only at the moment the contact was made; and a current in the contrary direction when the passage of the electricity was suddenly interrupted. These transitory currents, resembling waves, were found to be capable of magnetizing needles placed within the helix. Collateral currents, either in the same or in opposite directions, exert no permanent inductive power on each other.

scholarly journals To the determination of non-washable speed in the channels bed consisting of disconnected soils

2021 ◽  
Vol 264 ◽  
pp. 03011
Author(s):  
Luqmon Samiev ◽  
Qudratjon Rakhimov ◽  
Zaytuna Ibragimova ◽  
Davron Allayorov
Keyword(s):  
Experimental Data ◽  
Velocity Distribution ◽  
Deformation Process ◽  
Laboratory Studies ◽  
Trapezoidal Shape ◽  
Sand Particles ◽  
Different Diameters ◽  
Experimental Researches ◽  
Positive Results

This article analyzes the factors that influence the deformation process in the channel. When assessing the deformation process in channels consisting of disconnected soils, the method for determining nonwashable speed was analyzed, taking into account the trapezoidal shape of the channel, and, based on laboratory studies, a dependence was proposed for determining the non-washable speed. The values of the proposed dependencies are compared with the calculated values of the formulas of I.I. Levi, C.E. Mirtskhulava, V.A. Velikanova, B.I. Studenichnikov and A.M. Latyshenkov and obtained positive results. The proposed dependencies for the determination of non-washable speed are improved, taking into account turbulence and the laws of velocity distribution over the stream's depth. In the experimental researches, were used sand particles with different diameters d ≤ 0.315mm; 0.315mm < d ≤ 0.63mm; 0.63mm < d ≤1.25mm 1.25mm < d ≤ 2.5mm 2.5mm < d ≤ 5.0mm. Based on the analysis of the experimental data, the coefficients are as follows: η1 = 1.41 for the bottom of the channel and η2 = 1.52 for side slopes. The reliability of the results is justified by comparing the proposed calculation method with a study of other authors. Based on the research, constructed a plot of the velocity distribution and the depth of the stream. In these diagrams, preservation of the change in velocity along the depth of the flow was observed under various modes of motion. In all experiments, a process was observed-the smallest value of the flow velocity at the bottom and the highest at a depth of (0.8–0.9) h from the water level.

On the Nonlinear Multi-Physics Dynamics of a Mechanical Oscillator Coupled to an Electro-Magnetic Circuit

2012 ◽  
Author(s):  
Ioannis T. Georgiou ◽  
Francesco Romeo
Keyword(s):  
Electric Circuit ◽  
Coupled System ◽  
Fast Time ◽  
Mechanical Oscillator ◽  
Quadratic Nonlinearities ◽  
System Functioning ◽  
Harmonic Voltage ◽  
Numerical Tools ◽  
Electro Magnetic

The dynamics of a nonlinear electro-magneto-mechanical coupled system is addressed. Such a system exhibits a rich dynamic behavior arising from the involved quadratic nonlinearities that can be explored by relying on both analytical and numerical tools. It will be shown that the global multi-physics dynamic can be effectively handled to make the system functioning either as a sensor or an actuator for applications in the micro electromechanical context. Towards this goal, the roles played by the electro-magnetic and mechanical components in the resulting complex response, encompassing bifurcations as well as possible transitions from regular to chaotic motion, will be highlighted by means of Poincaré sections. Moreover, when the linear frequency of the circuit is larger than that of the mechanical oscillator, the dynamics exhibits slow and fast time scales. Therefore we analyze the mechanical oscillator forced (actuated) via harmonic voltage excitation of the electric circuit; when the forcing frequency is close to that of the mechanical oscillator, the long term dynamics are expected to evolve in a purely slow timescale, in the presence of dissipation, with no interaction with the fast time scale. We show this by assuming the existence of a slow invariant manifold, computing it analytically, and verifying its existence via numerical experiments on both full- and reduced-order systems.

II. Experimental researches in electricity.-twenty-second series (continued)

1849 ◽  
Vol 139 ◽  
pp. 19-41 ◽  
Keyword(s):  
Electric Current ◽  
The Body ◽  
Pure Zinc ◽  
Muriatic Acid ◽  
Magnetic Action ◽  
Original Direction ◽  
The Masses ◽  
Close Form ◽  
Magnetic Poles ◽  
Experimental Researches

2535. Zinc.—Plates of zinc broken out of crystallized masses gave irregular indications, and, being magnetic from the impurity in them, the effects might be due entirely to that circumstance. Pure zinc was thrown down electro-chemically on platina from solutions of the chloride and the sulphate. The former occurred in ramifying dendritic associations of small crystal; the latter in a compact close form. Both were free from magnetic action and freely diamagnetic, but neither showed any trace of the magnecrystallic action. 2536. Titanium.—Some good crystals of titanium obtained from the bottom of an iron furnace, were cleansed by the alternate action of acids and fluxes until as clear from iron as I could procure them. They were bright, well-formed and magnetic (2371), and contained iron, I think, diffused through their whole mass, for nitro-muriatic acid, by long boiling, continually removed titanium and iron from them. These crystals had a certain magnetic property which I am inclined to refer to their crystalline condition. When between the poles of the electro-magnet, they set; and when the electric current was discontinued, they still set between the poles of the enfeebled magnet as they did before. If left to itself a crystal always took the same position, showing that it was constantly rendered magnetic in the same direc­tion. But if a crystal was placed and kept in another position between the magnetic poles whilst the electric current was on, and afterwards the current suspended, and then the crystal set free, it pointed between the poles of the enfeebled magnet in this new direction; showing that the magnetism was in a different direction in the body of the crystal to that which it had before. If now the magnet were reinvigorated by the electric current, the crystal instantly spun round and took a magnetic state in the first or original direction. The crystals could in fact become magnetized in any direction, but there was one direction in which they could be magnetized with a facility and force greater than in any other. From the appearances I am inclined to refer this to the crystalline condition, but it may be due to an irregular diffusion of iron in the masses of titanium. The crystals were too small for me to make out the point clearly.

IV. Experimental researches in electricity. ─Twenty-fifth series

1851 ◽  
Vol 141 ◽  
pp. 85-122
Keyword(s):  
Stable Equilibrium ◽  
Copper Wire ◽  
External Diameter ◽  
The North ◽  
Hot Air ◽  
Freely Suspended ◽  
Magnetic Meridian ◽  
Experimental Researches ◽  
Requisite Amount ◽  
Magnetic Observatories

2969. Believing that experiment may do much for the development of the general principles of atmospheric magnetism, and produce rapidly a body of facts on which philosophers may proceed hereafter to raise a superstructure, I endeavoured to find some means of representing practically the action of the atmosphere, when heated by the sun, upon the terrestrial magnetic curves. The object was to obtain some central arrangement of force which should deflect these curves or lines as they are deflected in a diamagnetic conductor or globe of hot air (2877.), and then apply the results obtained by such an arrangement as a partial test to the various cases supplied by the magnetic observatories scattered over the earth. At first I endeavoured, for the sake of convenience, to attain this desired end by means of a horseshoe magnet, employing the lines which passed from pole to pole to disturb and rearrange the earth’s force; but the comparative weakness of the terrestrial force near the magnet, and the great prominence of the poles of the latter, gave rise to many inconveniences, which soon caused me to reject that method and have recourse to a ring-helix and voltaic apparatus. Considering the new use to which this helix is to be applied, the interest of the results, and the instruction that may be drawn from them, I shall be excused for being somewhat elementary in the description of its character and action. 2970. The helix consisted of about 12 feet of covered copper wire formed into a ring having about twenty-five convolutions, and being 1½ inch in external diameter. The continuations of the wire were twisted together so as to neutralize any magnetic effect which they could produce, and were long enough to reach to a voltaic arrangement, and yet allow free motion of the helix. The requisite amount of magnetic power in the helix may be judged of by the following considerations: —Suppose a declination needle freely suspended; and then the helix placed at a distance in the prolongation of the needle with its axis in a line with the latter, and with that side to­wards the needle which will at small distances cause repulsion. The needle will point, in the magnetic meridian, with a certain amount of force; but as the helix is brought near it will point with less force, and within a certain distance will no longer point in the magnetic meridian, but either on one or the other side of it. There is a given distance within which the needle, when in the magnetic meridian, is in a position of unstable equilibrium, but beyond which it has a position of stable equilibrium, the distance varying with the strength of the exciting electric current. The power of the helix should be such, that when end on to the needle the latter has a position of stable equilibrium in the meridian. One pair of plates is quite sufficient to make the helix as magnetic as is needful for distances varying from 4 to 24 inches. When a needle is properly arranged with either a magnet or a helix to the north or south of it as above described, if the magnet or helix be moved west the near end of the needle will move east, and contrariwise.

scholarly journals VIII. Experimental researches in electricity.—thirteenth series

1838 ◽  
Vol 128 ◽  
pp. 125-168 ◽  
Keyword(s):  
Secondary Effect ◽  
General Difference ◽  
Different Diameters ◽  
Experimental Researches ◽  
Considerable Size

1480. Let us now direct our attention to the general difference of the positive and negative disruptive discharge, with the object of tracing, as far as possible, the cause of that difference, and whether it depends on the charged conductors principally, or on the interposed dielectric; and as it appears to be great in air and nitrogen (1476.), let us observe the phenomena in air first. 1481. The general case is best understood by a reference to surfaces of considerable size rather than to points, which involve (as a secondary effect) the formation of currents (1562.). My investigation, therefore, was carried on with balls and terminations of different diameters, and the following are some of the principal results.

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