Distortion of a Magnetic Field by the Motion of a Cylindrical Conductor


Book Description

Motion of a conductor relative to a magnetic field distorts the field. This paper considers a cylindrical slug moving in a two-dimensional magnetic field, represented by the vector potential A sub 0 theta, where the partial derivative of A sub 0 with respect to theta = 0. Maxwell's equations are solved for the distorted potential A theta in the form of a rapidly converging series A = & A sub n. The A sub n's are given in a form suitable for evaluation by a digital computer. The nonequivalence of the apparently analogous problem of a stationary slug in a time-varying field is noted and discussed. (Author).




An Algorithm for the Deformation Method of Quadratic Programming


Book Description

The following paper represents work to date on the deformation method for quadratic programming and thus may be regarded as a sequel to Zahl, S. (1964) A Deformation Method for Quadratic Programming, Research Note AFCRL-63-132. It gives an explanation of a modified Iverson programming language and uses this to give a detailed algorithm for the Zahl Deformation Method of Quadratic Programming.




Earth-to-space Communications at Millimeter Wavelengths


Book Description

It is expected that with the exploration of outer space, a requirement for high data rate earth-to-space communication channels will arise. A program to investigate the feasibility of using the millimeter-wave region of the spectrum for this application is presented. The theory of atmospheric attenuation resulting from losses due to absorption, scattering and refraction processes is reviewed and used to estimate propagation losses produced by atmospheric gases, clouds and precipitation. Curves of total atmospheric attenuation and noise level as a function of meteorological parameters and antenna elevation angle are also presented. A series of experiments designed to obtain as much information as possible on the limitations imposed by the atmosphere on millimeter-wave propagation is considered. Although experiments using natural celestial bodies such as the sun, moon, planets and galaxies as radio sources are emphasized, those which would utilize aircraft, rockets and satellites are also mentioned. Finally, the characteristics of a recently installed precision 29-ft antenna designed to operate at 35 Gc (wavelength = 8.6 mm) with a traveling-wave maser as a preamplifier for the radiometer are outlined along with the specific experiments for which this antenna system will be used. (Author).







Nonlinear Terms in the Generalized Ohm's Law


Book Description

It is shown that a spatial gradient in the steady flow of an ionized gas introduces terms into the generalized Ohm's law that represent an exchange of momentum between the electrons and the gas flow. Depending upon the flow geometry and gas compressibility this electrokinetic exchange can behave like a generator, a Hall current, or a resistive current. The scale of the phenomenon is L = +/V, where V is fluid velocity, + is electron-positive charge collision time. Electrokinetic conditions apply largely at boundaries. In a resistive medium with a static B-field, the principal condition for electron-flow interchange is that magnetic pressure dominate dynamic pressure. At the boundary of a plasma jet the scale over which EK terms are important is of the order of 1 mm. Only geometry and scale considerations are used in the momentum equation. The electrokinetic generation of surface currents is as fundamental for describing moving media as spacecharge effects are in the static case. (Author).




On the Theory of Boolean Formulas


Book Description

The theory of substitutions for Boolean formulas developed in a previous report is applied here to the determination of those s-tuples of formulas that may be allowable replacements for s -tuples of sub-formulas of given Boolean formulas. The criteria of allowability are very general and flexible, yet may be expressed with great precision and ease. The results formalize and extend various known isolated instances. They may be used for the study of a large number of problems in the theory and application of Boolean formulas and functions.










Asymptotic Solutions of Dipoles in a Semi-infinite Medium


Book Description

A theoretical analysis is made of the electromagnetic fields in two homogeneous media separated by a plane interface with a point source located in the denser medium. The solution is expressed in the form of integrals which cannot be evaluated explicitly. Asymptotic evaluations of the integrals have been made by many investigators using the saddlepoint technique. In the present work, all known asymptotic results are presented in one comprehensive form, using a modification of the method suggested by Lighthill for the asymptotic evaluation of the Fourier integrals. The regions of validity of the solutions are indicated wherever possible. The advantage of this method over others is its ease and simplicity. The present results agree term by term with the earlier ones of Banos and Wesley (1953-1954), and Paul (1959), who investigated the case of a source and receiver close to the interface, and an arbitrary location of source and receiver, respectively. The results obtained in the report are also compared with those of Stein (1955). (Author).