2,309 research outputs found
Combustion/particle sizing experiments at the Naval Postgraduate School Combustion Research Laboratory
Particle behavior in combustion processes is an active research area at NPS. Currently, four research efforts are being conducted: (1) There is a long standing need to better understand the soot production and combustion processes in gas turbine combustors, both from a concern for improved engine life and to minimize exhaust particulates. Soot emissions are strongly effected by fuel composition and additives; (2) A more recent need for particle sizing/behavior measurements is in the combustor of a solid fuel ramjet which uses a metallized fuel. High speed motion pictures are being used to study rather large burning particles; (3) In solid propellant rocket motors, metals are used to improve specific impulse and/or to provide damping for combustion pressure oscillations. Particle sizing experiments are being conducted using diode arrays to measure the light intensity as a function of scattering angle; (4) Once a good quality hologram is attained, a need exists for obtaining the particle distributions from hologram in a short period of time. A Quantimet 720 Image Analyzer is being used to reconstruct images
Particle sizing in rocket motor studies utilizing hologram image processing
A technique of obtaining particle size information from holograms of combustion products is described. The holograms are obtained with a pulsed ruby laser through windows in a combustion chamber. The reconstruction is done with a krypton laser with the real image being viewed through a microscope. The particle size information is measured with a Quantimet 720 image processing system which can discriminate various features and perform measurements of the portions of interest in the image. Various problems that arise in the technique are discussed, especially those that are a consequence of the speckle due to the diffuse illumination used in the recording process
Issues in microenterprise employment, production and coping strategies in post-devaluation Dakar : the case of garment-making and woodworking firms
Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1996.Includes bibliographical references (p. 85-87).by John C. Powers, Jr.M.C.P
Ceramic component reliability with the restructured NASA/CARES computer program
The Ceramics Analysis and Reliability Evaluation of Structures (CARES) integrated design program on statistical fast fracture reliability and monolithic ceramic components is enhanced to include the use of a neutral data base, two-dimensional modeling, and variable problem size. The data base allows for the efficient transfer of element stresses, temperatures, and volumes/areas from the finite element output to the reliability analysis program. Elements are divided to insure a direct correspondence between the subelements and the Gaussian integration points. Two-dimensional modeling is accomplished by assessing the volume flaw reliability with shell elements. To demonstrate the improvements in the algorithm, example problems are selected from a round-robin conducted by WELFEP (WEakest Link failure probability prediction by Finite Element Postprocessors)
Magnetoplasmadynamic thrustor research Final report
Radiation-cooled and water-cooled magnetoplasmadynamic thrustors tested in 10 to kW power range with 1000 to 5000 sec specific impuls
COMMENTARY. tear strength of five elastomeric impression materials at two setting times and two tearing rates
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73584/1/j.1708-8240.2008.00177.x.pd
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