12,915 research outputs found
A study of stratospheric gases catalytically reacting on alumina
A vacuum system developed to study stratospheric gases reacting on Al2O3. Special attention was given to the reactions of HCl, SO2, and O3. Efforts were made to detect atoms and/or molecules produced by catalytic action of Al2O3 with mass spectrometer
Injector element characterization methodology
Characterization of liquid rocket engine injector elements is an important part of the development process for rocket engine combustion devices. Modern nonintrusive instrumentation for flow velocity and spray droplet size measurement, and automated, computer-controlled test facilities allow rapid, low-cost evaluation of injector element performance and behavior. Application of these methods in rocket engine development, paralleling their use in gas turbine engine development, will reduce rocket engine development cost and risk. The Alternate Turbopump (ATP) Hot Gas Systems (HGS) preburner injector elements were characterized using such methods, and the methodology and some of the results obtained will be shown
Managing Diversity and Glass Ceiling Initiatives as National Economic Imperatives
Glass Ceiling ReportGlassCeilingBackground5ManagingDiversity.pdf: 11584 downloads, before Oct. 1, 2020
Ultra thin gage plastic film
Process utilizing specially modified conventional equipment, with changes in process temperature, pressure, and cooling requirements produces ultra thin 1.56 micron /0.0614 mil/ thick polyethylene film
Servo-Stabilization of Low-Frequency Oscillations in a Liquid Bipropellant Rocket Motor
The recent work of H. S. Tsien concerning the servostabilization of rocket motors is extended to the liquid bipropellant rocket motor. It is shown that by use of a feedback system containing a device to sense the combustion chamber pressure, a suitably designed amplifier, and a servomechanism which governs the propellant How, the low-frequency oscillations which occur in the rocket configuration may be stabilized for any value of combustion time lag. A method is given for determining a transfer function of the feedback loop which will assure stable operation. The technique of the Satche diagram is employed in stability analysis
An investigation of the plastic fracture of high strength steels
Three generally recognized stages of plastic fracture in high strength steels are considered in detail. These stages consist of void initiation, void growth, and void coalescence. A brief review of the existing literature on plastic fracture is included along with an outline of the experimental approach used in the investigation
Temperature sensitivity of Eppley broadband radiometers
Broadband radiometers manufactured by Eppley Laboratories Inc. are commonly used to measure irradiance from both ground-based and aircraft platforms. Namely, the pyranometer (Model PSP) measures irradiance in the .3 to 3.0 micron spectral region while the pyrgeometer (Model PIR) senses energy in the 4 to 50 micron region. The two instruments have a similar thermopile construction but different filters to achieve the appropriate spectral selection. During the fall of 1986, the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) commenced with the first cirrus Intensive Field Observation (IFO) conducted in Central Wisconsin. Due to the nature of this field project, pyranometers and pyrgeometers manufactured by Eppley were flown on NCAR's high altitude research aircraft, the Sabreliner. Inherent in the construction of these radiometers is temperature compensation circuitry designed to make the instrument sensitivity nominally constant over a temperature range from -20 to +40 C. Because the Sabreliner flew at high altitudes where temperatures were as cold as -70 C, it was necessary to determine the radiometers relative sensitivity to temperatures below -20 C and apply appropriate corrections to the FIRE radiation data set. A procedure to perform this calibration is outlined. It is meant to serve as a supplement to calibration procedures
Radiative properties of cirrus clouds inferred from broadband measurements during FIRE
It is well known that clouds are significant modulators of weather and climate because of their effects on the radiation field and thus on the energy balance of the earth atmosphere system. As a result, the accurate prediction of weather and climate depends to a significant degree on the accuracy with which cloud radiation interactions can be described. The broadband radiative and microphysical properties of five cirrus cloud systems are reported, as observed from the NCAR Sabreliner during the FIRE first Cirrus IFO, in order to better understand cirrus cloud-radiation interactions. A broadband infrared (BBIR) radiative transfer model is used to deduce BBIR absorption coefficients in order to assess the impact of the cirrus clouds on infrared radiation. The relationships of these absorption coefficients to temperature and microphysical characteristics are explored
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