Equations for the comparison of the ballistic limit of single and double wall structures

1969 ◽  
Author(s):  
R. MADDEN
Keyword(s):  
Ballistic Limit ◽  
Wall Structures ◽  
Double Wall

scholarly journals Explorer 46 Meteoroid Bumper Experiment: Earth Orbital Debris Interpretation

1985 ◽  
Vol 85 ◽  
pp. 97-97 ◽  
Author(s):  
D.J. Kessler
Keyword(s):  
Aluminum Oxide ◽  
Size Range ◽  
Interplanetary Dust ◽  
Orbital Debris ◽  
Earth Orbit ◽  
Solid Rocket Motors ◽  
Rocket Motors ◽  
Wall Structures ◽  
Solid Rocket ◽  
Double Wall

AbstractThe Meteoroid Bumper Experiment on Explorer 46 (launched 1972) was placed in Earth orbit to evaluate the effectiveness of using double-wall structures against meteoroids. This paper re-examines the data from this experiment. Certain sets of sensors were found to be penetrated much more frequently than other sets. The most plausible explanation is that nearly all of the penetrations were from an Earth orbiting population of particulates. In addition, because a large percentage of the penetrations occured soon after solid rocket motors were fired in space, the particulates are most likely 75 μm diameter aluminum oxide. Aluminum oxide particulates are a major exhaust product from solid rocket motors. The size of particulates from most current solid rocket motors is found to range between 0.1 μm to 20 μm. Modeling the orbits of particulates from these rockets predicts that measurements in Earth orbit of interplanetary dust in this size range are also likely to include Earth orbiting particulates from solid rocket motors.

Modified Cour-Palais/Christiansen damage equations for double-wall structures

2006 ◽  
Vol 33 (1-12) ◽  
pp. 645-654 ◽  
Author(s):  
H.-G. Reimerdes ◽  
D. Nölke ◽  
F. Schäfer
Keyword(s):  
Wall Structures ◽  
Double Wall

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Ruthenium red and alcian blue effects on outer structures of methanotrophic bacteria

1988 ◽  
Vol 46 ◽  
pp. 72-73
Author(s):  
T.A. Fassel ◽  
M.J. Schaller ◽  
C.C. Remsen
Keyword(s):  
Research Effort ◽  
Ruthenium Red ◽  
Outer Cell ◽  
Methanotrophic Bacteria ◽  
En Bloc ◽  
Methylosinus Trichosporium ◽  
Wall Structures ◽  
Methylomonas Albus ◽  
Type Strains ◽  
Outer Cell Wall

Methane, a contributor to the “greenhouse effect”, is oxidized in the natural environment by methanotrophic bacteria. As part of a comprehensive research effort, we have been examining the ultrastructure of methanotrophs. These microorganisms have complex outer cell wall structures similar to those frequently found in other chemol itho- trophic bacteria. (1,2)In our work, we have focused on the “type” strains of Methylomonas albus BG8 and Methylosinus trichosporium OB3b. Between Spurr and LR White embedding resins, we found a difference 1n the preservation of an outer cup layer of BG8 external to the peripheral membranes. Cells from the same sample embedded in Spurr consistently lacked this feature (FIG. 1). This effect was overcome by an en bloc ruthenium red (RR) protocol that resulted in successful retention of the cup layer in Spurr resin (FIG. 2). For OB3b cells, the en bloc RR protocol resulted in an exterior bead feature distinguishable in thin section (FIG. 4) that previously was seen only by SEM.

Architecture of Radiolitid Rudist (Mollusca) Shell-Wall Structures and its Phylogenetic Implications

1975 ◽  
Vol 33 ◽  
pp. 686-687
Author(s):  
David H. Sturm ◽  
Bob F. Perkins
Keyword(s):  
Phylogenetic Relationships ◽  
Outer Wall ◽  
Shell Microstructure ◽  
Shell Wall ◽  
Wall Structures ◽  
Phylogenetic Implications ◽  
Cellular Wall ◽  
Superfamily Analysis ◽  
Central Texas

Each of the seven families of rudists (Mollusca, Bivalvia, Hippuritacea) is characterized by distinctive shell-wall architectures which reflect phylogenetic relationships within the superfamily. Analysis of the complex, calcareous, cellular wall of the attached valve of the radiolite rudist Eoradiolites davidsoni (Hill) from the Comanche Cretaceous of Central Texas indicates that its wall architecture is an elaboration of the simpler monopleurid rudist wall and supports possible radiolite-monopleurid relationships.Several well-preserved specimens of E. davidsoni were sectioned, polished, etched, and carbon and gold coated for SEM examination. Maximum shell microstructure detail was displayed by etching with a 0.7% HC1 solution from 80 to 100 seconds.The shell of E. davidsoni comprises a large, thick-walled, conical, attached valve (AV) and a small, very thin, operculate, free valve (FV) (Fig. 1a). The AV shell is two-layered with a thin inner wall, in which original structures are usually obliterated by recrystallization, and a thick, cellular, outer wall.

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