Failure of morphology of (0 deg)8 graphite/epoxy as influenced by environments and processing

Optical and scanning electron microscopy were used to investigate the failure morphology of graphite/epoxy specimens which had been tested until tensile failure. Failure morphology was studied as a function of the quality control variables of specimen preparation technique, prepreg batch, and cure condition, and also as a function of the environmental parameters of temperature and moisture content. Defective specimens were found to exhibit a low energy failure morphology. Poor specimen edge preparation and one batch of prepreg when tested at elevated temperature or moisture content also exhibited energy failure morphology. Postcuring had no effect on strength but did slightly alter failure morphology. Temperature or moisture appeared to decrease flaw sensitivity and thus increase strength; however, moisture also appeared to increase interfacial debonding between filament and matrix. When combined moisture and temperature increased interfacial debonding and made the epoxy matrix more prone to fracture

Barium cloud evolution and striation formation in the magnetospheric release on September 21, 1971

The joint NASA-Max Planck Institute Barium Ion Cloud (BIC) Experiment on September 21, 1971 involved the release of 1.7 kg of neutral barium at an altitude of 31,500 km at a latitude of 6.93 deg N. and a longitude of 74.40 deg W. A theoretical model describing the barium neutral cloud expansion and the ion cloud formation is developed. The mechanism of formation of the striational features observed in the release is also discussed. Two candidate instabilities, which may contribute to striation formation, are examined. The drift instability stemming from the outwardly directed drag force exerted on the ions by the outstreaming neutrals is rejected on the grounds that the ion density is too low during the collision-dominated phase of the cloud expansion to support this kind of instability. The joint action of Rayleigh-Taylor and flute instabilities plausibly accounts for the observed striational structure. This same mechanism may well be operative at times of sudden injection of plasma into the inner magnetosphere during geomagnetic storms and may thus contribute to the formation of field-alined inhomogeneities which serve as whistler ducts

Automatic navigation of a long range rocket vehicle

The flight of a rocket vehicle in the equatorial plane of a rotating earth is considered with possible disturbances in the atmosphere due to changes in density, in temperature, and in wind speed. These atmospheric disturbances together with possible deviations in weight and in moment of inertia of the vehicle tend to change the flight path away from the normal flight path. The paper gives the condition for the proper cut-off time for the rocket power, and the proper corrections in the elevator angle so that the vehicle will land at the chosen destination in spite of such disturbances. A scheme of tracking and automatic navigation involving a high-speed computer and elevator servo is suggested for this purpose

Integrated gas turbine engine-nacelle

A nacelle for use with a gas turbine engine is provided with an integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine. The nacelle is entirely supported in its spacial relationship with the engine by means of the webbed structure. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus, while the outer surface of the nacelle defines a streamlined envelope for the engine

Integrated gas turbine engine-nacelle

A nacelle for use with a gas turbine engine is presented. An integral webbed structure resembling a spoked wheel for rigidly interconnecting the nacelle and engine, provides lightweight support. The inner surface of the nacelle defines the outer limits of the engine motive fluid flow annulus while the outer surface of the nacelle defines a streamlined envelope for the engine

FEDERAL COURTS-MOTION FOR JUDGMENT UNDER RULE 50(B)POWER OF CIRCUIT COURT OF APPEALS TO DIRECT ENTRY OF JUDGMENT CONTRARY TO VERDICT DIRECTED BY THE TRIAL COURT

In an action for breach of warranty, defendants\u27 motion for a directed verdict was denied and verdict was directed for plaintiff. Defendants\u27 motion for a new trial was denied, and no motion was made for judgment in accordance with their previous motion for directed verdict. The circuit court of appeals reversed and remanded, with directions to enter judgment for defendants. On certiorari, held, reversed. Since defendants had not made timely motion for judgment under Rule 50 (b), the circuit court had no power to direct entry of judgment in their favor. Globe Liquor Co. v. San Roman, (U.S. 1948) 68 S.Ct. 246

A Thousand Humiliations: What Brown Could Not Do

Part One of this Article examines the Brown decisions and the aftermath. Part Two revisits the desegregation saga post-Green v. County School Board of New Kent County, Virginia, and the subsequent political and judicial forces which would doom desegregation efforts. Part Three examines the role that suburbanization and interstate highway transportation policies contributed to the frustration of desegregation efforts. This Article concludes by positing that in the context of modern public school reform, the promise of Brown is still elusive due to proposed legislative solutions, which once again, marginalize the interests of African-Americans

Tribute to Professor Judith P. Lipton

Tribute to Professor Judith P. Lipton