TRANSIENT FIELDS OF A VERTICAL DIPOLE OVER A HOMOGENEOUS CURVED GROUND

1956 ◽  
Vol 34 (1) ◽  
pp. 27-35 ◽  
Author(s):  
James R. Wait
Keyword(s):  
Dielectric Constant ◽  
Linear Function ◽  
Radiation Field ◽  
Step Function ◽  
Finite Conductivity ◽  
Function Form ◽  
The Earth ◽  
Vertical Antenna ◽  
A Current

Expressions are derived for the transient fields of a short vertical antenna, situated on a smooth spherical conducting earth, and energized by a current which is discontinuous in time. When the antenna current is a linear function of time, the radiation field on a flat perfectly conducting earth is of step-function form. The departure from the step shape of the field is shown to be due to the finite conductivity and dielectric constant of the ground, the induction and static fields of the antenna, and the curvature of the earth.

scholarly journals Eigenmode analysis of ballooning perturbations in the inner magnetosphere of the Earth

2007 ◽  
Vol 25 (6) ◽  
pp. 1391-1403 ◽  
Author(s):  
A. S. Parnowski
Keyword(s):  
Stability Criterion ◽  
Geomagnetic Field ◽  
Finite Conductivity ◽  
Nonlinear Structures ◽  
Magnetic Hydrodynamics ◽  
Longitudinal Displacement ◽  
Inner Magnetosphere ◽  
Transversal Displacement ◽  
The Earth ◽  
Eigenmode Analysis

Abstract. We analyze coupled Alfvén and slow magnetosonic eigenmodes in a dipole geomagnetic field with different ionospheric conductivities in the framework of ideal magnetic hydrodynamics (MHD) with finite pressure. We use numerical and, if possible, analytical methods to describe eigenmode frequencies, growth rates and eigenfunctions. The spectrum of Alfvén and slow magnetosonic modes is discrete and equidistant. The frequencies of the first Alfvén and slow magnetosonic eigenmodes are estimated as ~1 Hz and ~1 mHz, respectively. In the case of finite conductivity, periodic and aperiodic modes are separated and their interaction analyzed. It was shown that periodic and aperiodic perturbations can mutually transform into each other. A new flute stability criterion is derived (α~4.25), which is stricter than the Gold criterion (α=20/3). Here, as usual, α=−L/p dp/dL. For flute perturbations, the deviations of transversal displacement from a constant are calculated. An approximation for longitudinal displacement is derived. We determined the position of the main longitudinal peak, which can be responsible for nonlinear structures observed by Freja. An influence of nonlinear terms in pressure is estimated as well.

scholarly journals Characteristic Analysis of longitudinal vibration Sucker Rod String With Variable Equivalent Stiffness

2018 ◽  
Vol 153 ◽  
pp. 06009 ◽  
Author(s):  
Jian Lv ◽  
Mingming Xing
Keyword(s):  
Longitudinal Vibration ◽  
Step Function ◽  
Load Force ◽  
System Response ◽  
Equivalent Stiffness ◽  
Function Form ◽  
Characteristic Analysis ◽  
Response Curves ◽  
Sucker Rod ◽  
Force Excitation

Considering the influence of variable equivalent stiffness on system response, the equivalent stiffness is defined as a step function, and a mathematical model of nonlinear longitudinal vibration of sucker rod string (SRS) is built. The dynamic response under displacement and load force excitation is solved by fourth-order Runge-Kutta method with zero initial condition. The results show the steady-state responses under the displacement and load force excitation of different function forms are different. The response curves of both displacement and velocity under the displacement and load force excitation of cosine function form have larger fluctuation than it under the displacement and load force excitation of sine function form. Therefore, the characteristic analysis of SRS plays an important role in understanding the influence of the excitation form and sensitive parameters on steady response.

scholarly journals XXVII. On the relative speed of the electric wave through submarine cables of different lengths, and a unit of speed for comparing electric cables by bisecting the electric wave

1863 ◽  
Vol 12 ◽  
pp. 211-216
Keyword(s):  
The Other ◽  
Relative Speed ◽  
Submarine Cable ◽  
Electric Wave ◽  
Retarding Effect ◽  
The Earth ◽  
Current Flows ◽  
Electric Cables ◽  
Submarine Cables ◽  
A Current

The present paper gives the results of some experiments which were undertaken to determine, first, the relative speed of the electric wave through cables of various lengths; secondly, the retarding effect of the iron covering of the cable; and thirdly, methods for the increase of the speed of the electric wave. When a long submarine cable or subterranean wire is connected at one end through a galvanometer to the earth, and the other end is connected with a battery, a current flows through it, deflecting the galvanometer-needle.

REPLY BY D. RANKIN TO THE DISCUSSION BY J. T. WEAVER

Geophysics ◽  
1963 ◽  
Vol 28 (3) ◽  
pp. 490-490
Author(s):  
D. Rankin
Keyword(s):  
Electromagnetic Field ◽  
Plane Wave ◽  
Radiation Field ◽  
Free Space ◽  
Wave Incident ◽  
Induction Field ◽  
The Earth ◽  
Plane Wave Incident

I am indebted to Weaver if he has indeed clarified certain points which I had previously considered to be obvious. Cagniard (1953) states explicitly the magnitude of the wavelengths in free space and it is further implicit in the work of Rankin (1962) that it is indeed this same electromagnetic field which is being considered. The plane wave aspect of the problem arises from the extent of and not the distance from the source so that truly it is the induction field and not the radiation field that is under discussion. I had believed, until this note by Weaver, that d’Erceville and Kunetz (1962) also considered a plane wave incident on the earth and in fact that I was merely following both Cagniard and d’Erceville and Kunetz in this matter. The consistency of the results would tend to confirm this belief.

scholarly journals THE MAGNETIC PROPERTIES MEASUREMENT OF COIL FOR GRAVITATIONAL ACCELERATION DETERMINATION

2020 ◽  
Vol 5 (2) ◽  
pp. 119-128
Author(s):  
Cherly Salawane ◽  
Supriyadi Supriyadi ◽  
Ronaldo Talapessy ◽  
Mirtha Yunitha Sari Risakotta
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Field Strength ◽  
Electric Current ◽  
Graphical Method ◽  
Current Strength ◽  
Gravitational Acceleration ◽  
The Earth ◽  
The Magnetic Field ◽  
A Current

The value of the gravitational acceleration of the earth above the earth’s surface depends on the position of the latitude and longitude of the earth’s surface, in other words, because the shape of the earth’s surface is not round like a ball. The magnitude of gravity is not the same everywhere on the surface of the earth. The purpose of this study is to analyze the value of the earth’s gravitational acceleration in a laboratory using a current balance with a graphical method. Fluctuations in the value of the magnetic field strength (B) and the value of the electric current strength (i) on the current balance cause the value of laboratory gravitational acceleration (glab) to vary in the transfer of electric charge (q) according to coil type. The magnitude of the earth’s gravitational acceleration value obtained in a laboratory with a current balance for each type of coil is as follows: SF-37 glab-nr=9.89 m/s2, SF-38 glab-nr=9.90 m/s2, SF-39 glab-nr=9.76 m/s2, SF-40 glab-nr=9.95 m/s2, SF-41 glab-nr=9.75 m/s2 dan SF-42 glab-nr=9.93 m/s2. The results obtained indicate that the value of the earth’s gravitational acceleration in a laboratory close to the literature value is the value of the glab-nr in the SF-37 coil type of 9.89 m/s2.

scholarly journals Investigation of environment waste resultant from incorrect excretion of stock car rubbers and determination quantity, a current situation and fate of them (a case study: Ahvaz, Iran)

2015 ◽  
Vol 37 ◽  
pp. 260
Author(s):  
Mohsen Eslami ◽  
Farzaneh Fakeri Raof ◽  
Mohammad Jorjor Zadeh
Keyword(s):  
Automobile Industry ◽  
Well Being ◽  
Healthy Environment ◽  
The Earth ◽  
The World ◽  
In The Wild ◽  
Natural Equilibrium ◽  
Equilibrium Growth ◽  
A Current

A healthy environment is an absolute necessity for the well-being of all governments' policy. The population on the earth is expanding rapidly which goes hand in hand in the degradation of the environment at large measures. The human’s appetites for needs are disarranging the environments natural equilibrium. Growth of automobile industry in the world due to dignity to the parallel with increasing the production of rubber in the world. So increasing the disposal of worn tires is one of the world's great challenges. Annually, large amount of rubbers in the world is prepared. The rubber used in normal conditions can't be easily decomposed and make environmental pollution. This study was performed in Ahvaz metropolitan. The information in this study was achieved by questionnaire were asked of 40 shops, who was activated in the tire field. After this research revealed turned out about 300 shops were activated in the field of tires at the time of this study(2014), Also revealed 2700 tire rings out of cycle per day in Ahvaz .in this study (68%) questionnaire, believed that the tires after release from the workshop are collected by badger. (22%) believed that collected by municipal. Also (7%) of questionnaire believed that they didn't have any information about the release tires. At least only (3%) believed that himself collect damaged tires in their workshops. The application of the tire after collection in the idea of responded following: 15 person of questionnaire believe the tires sold after release from the workshop. 9 person said tires left in the wild. 8 persons believed that tires buried in a special place, Also 6 persons of questionnaire believed that tires are getting burned. At the end 2 persons of questionnaire believed that they don't know the fate of tires. At least some of the environmental hazards caused by incorrect tire were buried as were recommendation to improve.

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