Showing papers in "CTIT technical reports series in 1977"

Calibration of the SSJ/3 sensor on the DMSP satellites

Abstract: : The SSJ/3 sensor is designed to measure electrons from 50 eV to 20 keV. This is accomplished by using two head assemblies with common signal processing and voltage sources. The low-energy head assembly selects 50.0 to 1,000 eV electrons over eight channels with a normalization factor H = 0.000043 sq cm- ster. The high-energy assembly similarly selects 1.00 to 20.0 keV electrons over eight channels with an H-factor equal to 0.000013 sq cm-ster. Energy resolution is approximately 10% for an isotropic incident flux. An electron beam was used to determine angular and energy response. These measurements were compared with results from a Monte-Carlo computer code and approximate analytic methods to determine the final normalizations. (Author)

Nuclear emulsion measurements of the dose contribution from tissue disintegration stars on the Apollo-Soyuz mission

Abstract: A total of 996 disintegration stars were prong-counted in two 100 micron llford K.2 emulsions from the dosimeter of the Docking Pilot on Apollo-Soyuz. The change of slope of the distribution at a prong number of about 6 or 7 indicates 219 stars as originating in gelatin. Applying the QF values set forth in official regulations to the energy spectra of the proton and a alpha prongs of the gelatin stars leads to a tissue star dose of 7.8 millirad or 45 millirem. The quoted values do not include the dose contribution from star-produced neutrons since neutrons do not leave visible prongs in emulsion. Nuclear theory, in good agreement with measurements of galactic radiation in the earth's atmosphere, indicates that the dose equivalent from neutrons is about equal to the one from all ionizing secondaries of stars. Application of this proposition to the star prong spectrum found on Apollo-Soyuz would set the total tissue star dose for the mission at approximately 90 millirem.

Design of Electrostatic Analyzer.

Abstract: : This instrument is designed to detect and analyze precipitating electrons in the energy range from 50 eV to 20 keV. It is one of the supplementary sensors on board the Block 5D configuration satellites of the Defense Meteorological Satellite Program. Differential energy analysis is performed by a pair of electrostatic analyzers (ESA) in which a time sequenced variable electrostatic field deflects electrons of selected energies toward and exit aperture where they are counted by Channeltron Electron Multipliers (CEM). The small ESA covers energies ranging from 50 eV to 1 keV; the larger, 1 keV to 20 keV. The dwell time at each energy level is 98 ms, with both analyzers operating simultaneously. A complete 16 point spectrum is produced once per second and the 16 data words are transferred to the satellite on command. Figure 1 shows SSJ/3 with its test console. (Author)

Anomalous infrared emission from condensing and cooling steam clouds

Abstract: : The 10-micrometer wavelength, anomalous infrared emission from condensing and cooling clouds of saturated steam at atmospheric pressure was measured. Radiant emittance values were observed which were three to four times those calculated for water droplets and water vapor present in the clouds. Near 100 C, luminescence-like activity was observed confirming earlier observations by other workers.

Basic and Applied Research in Materials

Abstract: : Research has been carried out in two areas: heterogeneous catalysis and materials for energy storage. In the first project, standard batches of Pt/ SiO2 catalysts were prepared and characterized utilizing a variety of techniques, e.g., x-ray diffraction, isotopic exchange between deuterium and cyclopentane, etc. The purpose of these studies is to elucidate information on the nature of the catalyst crystallites, the effect of the support upon the catalyst behavior, the effect of metallic particle size on catalytic characteristics and the effect of the method of catalyst preparation upon catalytic activity. The results of the final sets of measurements are presented.

Testing of Turbulence Models by Exact Numerical Solution of the Navier-Stokes Equations.

Abstract: : This report presents preliminary results from a continuing study in which the validity of models used in large-eddy simulations of turbulent flow is tested by comparison with results from an exact simulation using the Navier-Stokes equations The results to date are for models of the eddy-viscosity type applied to a homogeneous isotropic incompressible flow More complicated flows and models will be considered in future phases of this study (Author)

Improved dual-mode electron gun

Abstract: : An advanced non-intercepting gridded gun was designed, fabricated, and preliminary tested. The use of magnetic flux in the cathode region preserves the beam diameter when the grid voltage is reduced for a lower power mode of operation. This will result in a more stable TWT performance, since the gain difference associated with the two modes is significantly reduced. (Author)

AOIPS data base management systems support for GARP data sets

Abstract: A data base management system is identified, developed to provide flexible access to data sets produced by GARP during its data systems tests. The content and coverage of the data base are defined and a computer-aided, interactive information storage and retrieval system, implemented to facilitate access to user specified data subsets, is described. The computer programs developed to provide the capability were implemented on the highly interactive, minicomputer-based AOIPS and are referred to as the data retrieval system (DRS). Implemented as a user interactive but menu guided system, the DRS permits users to inventory the data tape library and create duplicate or subset data sets based on a user selected window defined by time and latitude/longitude boundaries. The DRS permits users to select, display, or produce formatted hard copy of individual data items contained within the data records.

Development of an Improved Separator Material for Alkaline Silver-Zinc Batteries

Abstract: : This work was a preliminary investigation to determine if polyphenylquinoxaline (PPQ) or a codispersed mixture of polyvinylpyrrolidone (PVP) with PPQ could be used to replace cellophane as a separator in the zinc- silver oxide battery. The primary purpose was to compare its dimensional and chemical stability with cellophane and to determine if methods could be developed to lower its high inherent electrical resistance. Dimensional measurements were made in 45% KOH at 298 K (25 C) and 353 K (80 C). Chemical stability to oxidation was observed in KOH solution saturated with silver oxide at 353 K. In an effort to lower the resistance of these thin film membranes, various methods were studied to develop porosity. Included among these were extraction of the PVP in boiling water, pyrolysis of the PVP, swelling of the films with phenol, and precipitation of the PPQ from acetone. Increasing the molecular weight of the PVP appears very promising and additional studies are recommended since these polymers have good potential use as separators.

Backscattering of Radar Waves by Vegetated Terrain.

Abstract: : This report presents a vector theory for the backscattering of electromagnetic radar waves from vegetation. The basic technique employed in the solution required simulating the vegetation with a random medium. This medium possesses an electrical permittivity that is generated by a continuous random process and is characterized by a particular probability density function. A solution for the radar backscatter coefficient is obtained in terms of the statistical characteristics of the random medium. A comparison of the theory with experimental data is given. Insight is given into the nature of depolarization, but explicit results for the depolarized terms are not obtained at this time because of the complexity and difficulty of the solution. Some of the conclusions of this work are: a theory has been developed for computing the like polarized (HH and VV) radar backscatter coefficients from certain types of vegetation by using a vector renormalization approach; no rigorous quantitative comparison of theory with experiment was possible; however, qualitative comparisons indicate reasonable agreement; and although no explicit solution was obtained for the depolarization components, it was learned that one cause of depolarization is the anisotropy associated with the correlation function of the dielectric fluctuations. (Author)

Methods for the evaluation of alternative disaster warning systems

Abstract: For each of the methods identified, a theoretical basis is provided and an illustrative example is described. The example includes sufficient realism and detail to enable an analyst to conduct an evaluation of other systems. The methods discussed in the study include equal capability cost analysis, consumers' surplus, and statistical decision theory.