Stress-intensity factor and crack opening for a linearly viscoelastic strip with a slowly propagating central crack
Linearly viscoelastic strip with slowly propagating central crack, calculating stress intensity factor and crack opening size
SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Linearly viscoelastic strip with slowly propagating central crack, calculating stress intensity factor and crack opening size
Arterial baroreceptor reflex action in rabbits, noting central noradrenergic neuron participation
Spinning centrally clamped thin shallow spherical shell free vibration numerical analysis by considering perturbation about equilibrium configuration
Retinal adaptation to prism-displaced hand image in terms of sensorimotor coordination central control change
Grand Tour missions centralized data handling, describing computer aided telemetry system and self testing and repairing control computer
Central nervous tissue sensitivity, considering direct sensing of gravitational stimuli of vibratory character
Visual perceptual masking under binocular and dichoptic conditions separating peripheral and central interference effects
Fission track and K-Ar ages of coexisting minerals in drill core from heat-flow boreholes in western central Sierra Nevada batholith
Central panel luminance effect on peripheral visual detection time in search tasks
The central computer and sequencer subsystem has been an important part of the Mariner series of interplanetary spacecraft since their inception. As with other spacecraft subsystems, the CC&S has increased in complexity and capability with each spacecraft project. This report describes the design, fabrication, and test associated with the development of the Mariner Mars 1971 CC&S subsystem.
Hole-in-the-Ground, a volcanic explosion crater, located in central Oregon is described. The morphology of the soil and rocks and the topography of the crater indicate the sequential happenings during the eruption. Geophysical measurements also indicate a domical intrusion below the crater floor, extending upward as a ring dike around the margins of the crater. The volume of ejecta was determined for four major eruptions. Varied analyses were made of the pyroclastic debris, rocks, cinders, and soil.
The work of the Central Atlantic Regional Ecological Test Site (CARETS) project is discussed. The primary aim of CARETS is to test the hypothesis that data from ERTS-A can be made an integral part of a regional land resources information system, encompassing both inventory of the resource base and monitoring of changes, along with their effects on the quality of the environment. Another objective of the project is to determine scaling factors for developing land use information and regional analysis for regions of any given size.
The author has identified the following significant results. Prior to the actual testing of data from ERTS-1, the principal scientific results to date are the establishment of a model or design for a regional land use information system based on remote sensor data and a firm establishment of the RB-57 type high altitude aircraft data base as an important tool in land use mapping. Preliminary user evaluations of the resulting land use data have been favorable, and one of the states, Maryland, has adopted the USGS-GAP land use system as a first step towards mapping their entire state. The State is funding an extension (to the west) of the part of Maryland not covered by CARETS (Central Atlantic Regional Ecological Test Site), using the GAP land use classification and mapping procedures.
Three subjects performed from 15 to 20 bouts of 10-min bicycle ergometer exercise in a 26 C ambient. The procedure imposed a consistent pattern of internal (esophageal) temperature increase in the presence of a constant mean skin temperature. Body weight loss was continuously recorded and rate of evaporative loss due to sweating was calculated during each minute of exercise. It was confirmed that both local and total sweating are functions of internal temperature at a fixed constant mean skin temperature. In the presence of a constant central drive for sweating, the sweating response could be modified at the periphery according to the area-specific characteristics and/or by local temperature.
The central power crisis, and the present and relatively near-time contributions that aerospace technology is making to help solve this crisis are discussed. The principal emphasis is placed on the prospects of aerospace derived magnetohydrodynamic (MHD) large scale power generation. The strides that the Soviet Union is making in this field with the startup of the new U-25 plant near Moscow, having a total power capability of 75 MW, are reviewed. A much smaller program in the U.S. is outlined, and prospects of future benefits are discussed.
A technique for the noninvasive measurement of CVP in man was developed. The method involves monitoring venous velocity at a point in the periphery with a transcutaneous Doppler ultrasonic velocity meter while the patient performs a forced expiratory maneuver. The idea is the CVP is related to the value of pressure measured at the mouth which just stops the flow in the vein. Two improvements were made over the original procedure. First, the site of venous velocity measurement was shifted from a vein at the antecubital fossa (elbow) to the right external jugular vein in the neck. This allows for sensing more readily events occurring in the central veins. Secondly, and perhaps most significantly, a procedure for obtaining a curve of relative mean venous velocity vs mouth pressure was developed.
Significant quantities that affect the internal structure of the sun are examined for factors that reduce the temperature near the sun's center. The four factors discussed are: opacity, central black hole, thermal instability, and additional neutrino sources.
The author has identified the following significant results. Information obtained by remote sensing from three altitude levels: ERTS-1 (565 miles), U-2 (60,000 feet), and C-130 aircraft (15,000 feet) illustrates the possible application of multilevel sensing in mineral exploration. Distinction can be made between rocks of greenstone belts and rocks of granite-granite gneiss areas by using ERTS-1 imagery in portions of the Precambrian of central Wyoming. Study of low altitude color and color infrared photographs of the mafic terrain revealed the presence of metasedimentary rocks with distinct layers that were interpreted as amphibolite by photogeologic techniques. Some of the amphibolite layers were found to be iron formation when examined in the field. To our knowledge this occurrence of iron formation has not been previously reported in the literature.