Shaped cassegrain reflector antenna

Design equations are developed to compute the reflector surfaces required to produce uniform illumination on the main reflector of a cassegrain system when the feed pattern is specified. The final equations are somewhat simple and straightforward to solve (using a computer) compared to the ones which exist already in the literature. Step by step procedure for solving the design equations is discussed in detail

RFI emitter location techniques

The possibility is discussed of using Doppler techniques for determining the location of ground based emitters causing radio frequency interference with low orbiting satellites. An error analysis indicates that it is possible to find the emitter location within an error range of 2 n.mi. The parameters which determine the required satellite receiver characteristic are discussed briefly along with the non-real time signal processing which may by used in obtaining the Doppler curve. Finally, the required characteristics of the satellite antenna are analyzed

On the Second Fundamental Theorem of Asset Pricing

Let $X^1,\ldots, X^d$ be sigma-martingales on $(\Omega,{\cal F}, P)$. We show that every bounded martingale (with respect to the underlying filtration) admits an integral representation w.r.t. $X^1,\ldots, X^d$ if and only if there is no equivalent probability measure (other than $P$) under which $X^1,\ldots,X^d$ are sigma-martingales. From this we deduce the second fundamental theorem of asset pricing- that completeness of a market is equivalent to uniqueness of Equivalent Sigma-Martingale Measure (ESMM)

Initial stages of cavitation damage and erosion on copper and brass tested in a rotating disk device

In view of the differences in flow and experimental conditions, there has been a continuing debate as to whether or not the ultrasonic method of producing cavitation damage is similar to the damage occurring in cavitating flow systems, namely, venturi and rotating disk devices. In this paper, the progress of cavitation damage during incubation periods on polycrystalline copper and brass tested in a rotating disk device is presented. The results indicate several similarities and differences in the damage mechanism encountered in a rotating disk device (which simulates field rotary devices) and a magnetostriction apparatus. The macroscopic erosion appears similar to that in the vibratory device except for nonuniform erosion and apparent plastic flow during the initial damage phase

A short, cylindrical antenna as a diagnostic probe for measuring collision frequencies in a collision-dominated, non-Maxwellian plasma

Effects of particle collisions on antiresonant characteristics of cylindrical antennas used in electron plasma temperature and density measurement

Origin and evolution of Gneiss-Charnockite rocks of Dharmapuri District, Tamil Nadu, India

A low- to high-grade transition area in Dharmapuri district was investigated petrologically and geochemically. The investigation confirmed the presence of a continuous section through a former lower crust, with felsic charnockites predominating the lower part and felsic gneisses the upper part. The structure of original gneisses is preserved in charnockites and the latter show petrographic evidence for prograde metamorphism. The prograde metamorphism is of isochemical nature as revealed by the similarity of compositions of tonalitic gneisses and tonalitic charnockites. However, the depletion of LIL elements particularly Rb, caused variation in K/Rb ratios from low values (345) in the gneisses in upper part to higher values (1775) in the charnockites in the lower crust. This variation in K/Rb ratio in a north to south traverse is related to the progressive break-down of hydrous minerals under decreasing H2O and increasing CO2 fluid conditions. Metasomatism and partial melting has also taken place to a limited extent along shear planes and weak zones. During cooling the H2O circulation affected substantial auto-regression in the transition zone resulting in the formation of second generation biotite