Thermionic cathode life test studies

An update on the life testing of commerical, high current density impregnated tungsten cathodes is presented. The B-type cathodes, operated at a current density of 2 A/cm2 and a cathode temperature of 1100 C have now been run satisfactorily for more than four years. The M-cathode, at the same current density but at an operating temperature of only 1010 C, have been tested for more than three years. The M-cathodes show no degradation in current over their present operating life whereas the current from the B-cathodes degrade about 6 percent after four years of operation

Dual Fronts Propagating into an Unstable State

The interface between an unstable state and a stable state usually develops a single confined front travelling with constant velocity into the unstable state. Recently, the splitting of such an interface into {\em two} fronts propagating with {\em different} velocities was observed numerically in a magnetic system. The intermediate state is unstable and grows linearly in time. We first establish rigorously the existence of this phenomenon, called ``dual front,'' for a class of structurally unstable one-component models. Then we use this insight to explain dual fronts for a generic two-component reaction-diffusion system, and for the magnetic system.Comment: 19 pages, Postscript, A

MS

thesisThis study was made to determine the value of efficiency studies of various aspects of coal mining. Studies were made of air coursings and the effect of adding or eliminating air courses on fan performance. Mine characteristics were compared under different conditions of fans9 stopped and running, at several blade settings. Power costs were compared for various quantities and circumstances. A detailed study of a hoist indicated that it was underloaded even though it was causing the loaders to be delayed. Steps were taken to correct the defect. The results of this analysis indicate that efficiency studies of mining operations and equipment can save much money for a mining company

Hiligaynon Reference Grammar

Humanities Open Book Program, a joint initiative of the National Endowment for the Humanities and the Andrew W. Mellon FoundationThe Philippines series of the PALI Language Texts, under the general editorship of Howard P. McKaughan, consists of lesson textbooks, grammars, and dictionaries for seven major Filipino languages

Golden Shiner, Bluegill, and Green Sunfish Production in a small Lake

A small lake located 43 miles southeast of Dallas in Kauf­man County, owned by Dr. Ozro T. Woods, was treated with rotenone in February, 1952. With a surface area of about two acres, the lake contained 5.4 acre-feet of water, with a maximum depth of six feet. It was constructed in 1947 and filled the same year

Non-conventional control of the flexible pole-cart balancing problem

Emerging techniques of intelligent or learning control seem attractive for applications in manufacturing and robotics. It is however important to understand the capabilities of such control systems. In the past the inverted pendulum has been used as a test case. The thesis begins with an examination of whether the inverted pendulum or polecart balancing problem is a representative problem for experimentation for learning controllers for complex nonlinear systems. Results of previous research concerning the inverted pendulum problem are presented to show that this problem is not sufficiently testing. This thesis therefore concentrates on the control of the inverted pendulum with an additional degree of freedom as a testing demonstrator problem for learning control system experimentation. A flexible pole is used in place of a rigid one. The transverse displacement of the flexible pole adds a degree of freedom to the system. The dynamics of this new system are more complex as the system needs additional parameters to be defIned due to the pole's elastic deflection. This problem also has many of the signifIcant features associated with flexible robots with lightweight links as applied in manufacturing. Novel neural network and fuzzy control systems are presented that control such a system both in simulation and real time. A fuzzy-genetic approach is also demonstrated that allows the creation of fuzzy control systems without the use of extensive knowledge