摘要:

The paper has for its principal object the theoretical and experimental investigation of the electric field produced when a current flows in an electrolytic cell having plane parallel electrodes.On the theoretical side a general expression for the electrolytic conductance is derived in terms of the stream flux and the potential difference between the electrodes, and is applied to special problems of complex transformations. The distribution of the electric stress along the surface of parallel plane electrodes is also determined mathematically (see Section 1).The experimental work has been planned with two objects in view : (1) To verify the theoretical results by means of experiments in which the mathematical conditions are represented with sufficient and reasonable accuracy (see Sections 2 and 3) ; and (2) to apply the theoretical results for the solution of certain practical questions, and to investigate experimentally how far such applications agree with test results (see Section 4). Both objects have been in some measure satisfactorily attained.On the side of electro-physics the validity of Ohm's law is proved for any elemental current in the electrolyte by a direct experiment devised for this purpose (see Section. 3). The significance of this result lies first in its providing tangible evidence of the coincidence of stream lines with lines of force everywhere in the electrolytic medium, and secondly, in its proving that under certain conditions an electrolytic may be taken to represent a perfect homogeneous dielectric with something approaching mathematical precision. As an example of the practical application of this theorem, a method is derived for calculating the conductance of such apparatus as metal-refining and simple electro-deposition tanks, and certain types of liquid rheostats. A practical chart which is provided for this purpose may prove useful to the designers of such apparatus (see Section 4).Furthermore, the results obtained may find a field of application in the measurement of electrical and magnetic phenomena where the distribution of energy is analogous to that shown to exist in the electrolytic cell, as, for example, the capacity of an irregular system of conductors or the eluctance of a magnetic circuit.

DOI:10.1049/jiee-1.1924.0041

出版商:IEE    

年代:1924

数据来源: IET

DOI:10.1049/jiee-1.1924.0042

出版商:IEE    

年代:1924

数据来源: IET

摘要:

The author makes a plea for British investigation and design in order to produce a lift more especially suitable to conditions in this country than is possible by following American practice too closely. A number of problems requiring investigation are referred to. The essential parts of a lift and the factors of cost are stated. The advisability of consulting specialist engineers with regard to new construction is suggested. A complaint is made that lift makers are often consulted too late in the development of a new building to enable them to offer the best and most economical scheme. It is maintained that a lift service is more important than the provision of stairs.The methods employed by the author in calculating the lift capacity required in a building are outlined. A plea is advanced for the employment of lifts of higher running speed and improved acceleration, and the method adopted by the author in an investigation of acceleration problems is described.A comparison is made between drum and sheave driving. The effects of the position of the winding engine and of rope-reeving upon maintenance cost are discussed. Types of worm gearing and methods of control are described and the limitations of automatic control emphasized. Microdrive and decelerator devices for attaining automatic floor levelling are detailed and reference is made to a new system of control—the “Auto-Pilot.”Safety devices employed in connection with passenger lifts are described, and the record and infrequency of accidents are discussed and commented upon.

DOI:10.1049/jiee-1.1924.0046

出版商:IEE    

年代:1924

数据来源: IET

摘要:

The paper contains a mathematical analysis of the effect of an atmospheric upon a wireless receiver. The choice of functions representing the atmospheric has been governed by information contained inProceedings of the Royal Society, A, vol. 103. The effect of each of several wave-forms is calculated and the results are compared. The effect is calculated of an atmospheric acting respectively on a tuned antenna, on an aperiodic antenna, on a tuned loop aerial, and also the combination of each of these with a selective amplifier. In each case a formula is derived which gives the ratio of signal to atmospheric, and it is shown that for a given wave-length these formulæ are identical. The possible advantage to be got from the use of an aperiodic antenna or of a slightly distuned periodic circuit is considered in detail. Finally, the rectified current produced by the atmospheric is compared with that produced by the signal, and it is shown that the decrement of the aerial should always be reduced to the point where ringing or bad shaping of signals commences.

DOI:10.1049/jiee-1.1924.0051

出版商:IEE    

年代:1924

数据来源: IET