Tensile behavior of unnotched and notched tungsten-copper laminar composites

Relations were studied between the tensile strengths of unnotched and of notched, and elastic moduli of unnotched laminar sheet or foil composites and the amounts of reinforcement. Tungsten was used as the reinforcement and copper as the matrix, and the tests were run at room temperature. Three thicknesses of tungsten (i.e., 0.00254, 0.0127, and 0.0254 cm (0.001, 0.005, and 0.010 in) were used and the nominal volume fraction of tungsten was varied from about 0.05 to 0.95. It was found that the tensile strength of the unnotched specimens could be related to the amount of reinforcement, as could the elastic moduli, and that these values could be predicted by use of the rule of mixtures. The tensile strengths of the notched laminar composites could be predicted by use of the rule of mixtures using strengths for notched constituents, provided notch effects did not predominate

Effect of discontinuities as a means to alleviate thermal expansion mismatch damage in laminar composites

An investigation of Nichrome/tungsten laminar composites showed that intentionally introduced discontinuities, such as perforations through or grooves on the surface of the matrix laminae, improved thermal expansion mismatch damage resistance. It was found that specimens having smooth matrix laminate surfaces were virtually destroyed by delamination in 21 or fewer fast cool cycles in which they were water quenched from 981 C. Specimens having interior matrix laminae with discontinuities and relatively thin, nondiscontinuous, surface matrix laminae resisted 50 similar cycles without evident delamination damage

Metal-metal reinforced laminar composites

Two prototype laminar composites have shown potential for high strength and high temperature applications. These composites might be made with less in-place anisotropy and be less expensive than comparable fiber composites

Self-protecting solid state isolated switch

Solid state switch has following capabilities: (1) Hybrid or IC from compatible with direct mounting on solar array substrate; (2) Continuous signal is not required to hold it in either on or off state; (3) Separate signal lines for on and off control; (4) Electrically isolated from input signals; and (5) Current surges will not cause switch failure

Price Determination for Corn and Wheat: The Role of Market Factors and Government Programs

Annual models for U.S. farm prices for corn and wheat are developed based on market factors as well as government agricultural commodity programs. The pricing relationships utilize a stocks-to-use modeling framework to capture the effects of market supply and demand factors on price determination. This formulation is augmented by factors that represent the changing role of agricultural policies, particularly government price support and stockholding programs. For wheat, international market effects as well as wheat feed use and related crosscommodity pricing considerations also are included. Model properties and model performance measures are presented. Additionally, recent price-forecasting applications of the models are discussed. The relatively simple structure of the estimated price models and their small data requirements lend themselves to use in price-forecasting applications in conjunction with market analysis of supply and demand conditions. In particular, the models have been implemented into USDAís short-term market analysis and long-term baseline projections. In these applications, the models provide an analytical framework to forecast prices and a vehicle for making consistency checks among the Departmentís supply, demand, and price forecasts.corn, wheat, farm price, price determination, stocks-to-use ratio, price supports, commodity programs, forecasts, Crop Production/Industries, Demand and Price Analysis,

Electrode current distributions in MGD CHANNELS

Current distribution to and electric field behavior of segmented electrodes in linear magnetogasdynamic generato

Metal-metal laminar composites for high temperature applications

A study was conducted to obtain indications of the potentialities of laminar metal-metal composites for elevated temperature use. Most of the composites consisted of multiple layers or laminae of tungsten alternated with laminae of Nichrome V, a ductile, weaker but oxidation-resistant alloy. Composites with 50 volume percent of each phase were tested in tension and stress rupture at temperatures of 871 and 1093 C (1600 and 2000 F) and in impact at 23 and 524 C (73 and 975 F). A tension and a short time stress-rupture test was conducted on specimens of 77 v/o W-Re-Hf-C/23 v/o Inconel alloy 600 at 1093 C (2000 F)

Maclisp extensions

A common subset of selected facilities available in Maclisp and its derivatives (PDP-10 and Multics Maclisp, Lisp Machine Lisp (Zetalisp), and NIL) is decribed. The object is to add in writing code which can run compatibly in more than one of these environments