High-altitude observations of a luminous wake behind two Black Brant II rockets

1968 ◽  
Vol 46 (24) ◽  
pp. 2753-2754 ◽  
Author(s):  
D. D. Wallis ◽  
C. D. Anger
Keyword(s):  
High Altitude ◽  
Circular Cone ◽  
Black Brant ◽  
Half Angle ◽  
Luminous Region

Measurements of a luminous region following two Black Brant II rockets are presented. This luminous region or wake appears as a circular cone of half angle 4° and length less than 1 km lying along the trajectory of the rocket, with vertex near the rocket. The wake was observed between 80 and 115 km at 4278 Å, but was not observed at 5577 Å.

On fluid motions induced by an electric current source

1971 ◽  
Vol 46 (1) ◽  
pp. 25-32 ◽  
Author(s):  
C. Sozou
Keyword(s):  
Electromagnetic Field ◽  
Linear Problem ◽  
Flow Problem ◽  
Current Source ◽  
Inviscid Flow ◽  
Circular Cone ◽  
Infinite Plane ◽  
Half Angle ◽  
Whole Space ◽  
Electric Current Source

In this paper we consider the flow field induced in an incompressible viscous conducting fluid, occupying the interior of a right circular cone, by an electriccurrent source situated at the vertex of the cone. We assume that the velocity field is small and its effect on the electromagnetic field is negligible. A similarity solution is obtained for the non-linear problem. This solution is an adaptation of Slezkin's solution for the momentum transfer through a viscous jet and, apart from the numerical solution of a Riccati type of equation, is exact. In particular, we investigate the case when the half angle of the cone is ½π and the fluid occupies the whole space on one side of an infinite plane. We also consider the corresponding inviscid flow problem that was recently investigated by another author and suggest that the solution obtained is not physically realistic.

Finite Fringe Holographic Interferometry Applied to a Right Circular Cone at Angle of Attack

1972 ◽  
Vol 39 (4) ◽  
pp. 897-903 ◽  
Author(s):  
R. C. Jagota ◽  
D. J. Collins
Keyword(s):  
Holographic Interferometry ◽  
Present Report ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Density Field ◽  
Circular Cone ◽  
Governing Equations ◽  
Wind Tunnel Experiments ◽  
Three Dimensional Flow ◽  
Half Angle

The successful application of holography to the study of three-dimensional flow fields due to phase objects has been reported in the literature. The present report extends this technique to the study of density fields around opaque bodies as would normally be encountered in wind tunnel experiments. The density field around a 10-deg half-angle cone at 0 and 10-deg angle of attack has been investigated by means of the finite fringe holographic interferometry. The three-dimensional density field obtained from the reduction of the interferograms was found to agree with that obtained from an analytical solution of the governing equations.

Contrast of Filament Bright Rims

1994 ◽  
Vol 144 ◽  
pp. 365-367
Author(s):  
E. V. Kononovich ◽  
O. B. Smirnova ◽  
P. Heinzel ◽  
P. Kotrč
Keyword(s):  
High Altitude ◽  
Line Profile ◽  
Line Center ◽  
Magnetic Structures ◽  
The Mean

AbstractThe Hα filtergrams obtained at Tjan-Shan High Altitude Observatory near Alma-Ata (Moscow University Station) were measured in order to specify the bright rims contrast at different points along the line profile (0.0; ± 0.25; ± 0.5; ± 0.75 and ± 1.0 Å). The mean contrast value in the line center is about 25 percent. The bright rims interpretation as the bases of magnetic structures supporting the filaments is suggested.

Clean Electron Microscope Substrate Films Used for Micrometeorite Collection and Study

1967 ◽  
Vol 25 ◽  
pp. 366-367
Author(s):  
D. M. Davies ◽  
R. Kemner ◽  
E. F. Fullam
Keyword(s):  
Thin Film ◽  
Electron Microscope ◽  
High Altitude ◽  
Amyl Acetate ◽  
Temperature Variations ◽  
Film Forming ◽  
Film Specimen ◽  
Particulate Contaminants

All serious electron microscopists at one time or another have been concerned with the cleanliness and freedom from artifacts of thin film specimen support substrates. This is particularly important where there are relatively few particles of a sample to be found for study, as in the case of micrometeorite collections. For the deposition of such celestial garbage through the use of balloons, rockets, and aircraft, the thin film substrates must have not only all the attributes necessary for use in the electron microscope, but also be able to withstand rather wide temperature variations at high altitude, vibration and shock inherent in the collection vehicle's operation and occasionally an unscheduled violent landing.Nitrocellulose has been selected as a film forming material that meets these requirements yet lends itself to a relatively simple clean-up procedure to remove particulate contaminants. A 1% nitrocellulose solution is prepared by dissolving “Parlodion” in redistilled amyl acetate from which all moisture has been removed.

Resolution Attainable With the Present Day STEM

1973 ◽  
Vol 31 ◽  
pp. 230-231 ◽  
Author(s):  
J. S. Wall ◽  
J. P. Langmore ◽  
H. Isaacson ◽  
A. V. Crewe
Keyword(s):  
Spherical Aberration ◽  
Focal Length ◽  
Incident Beam ◽  
Scanning Transmission Electron Microscope ◽  
Aperture Size ◽  
Magnetic Lens ◽  
Peak Intensity ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Half Angle

The scanning transmission electron microscope (STEM) constructed by the authors employs a field emission gun and a 1.15 mm focal length magnetic lens to produce a probe on the specimen. The aperture size is chosen to allow one wavelength of spherical aberration at the edge of the objective aperture. Under these conditions the profile of the focused spot is expected to be similar to an Airy intensity distribution with the first zero at the same point but with a peak intensity 80 per cent of that which would be obtained If the lens had no aberration. This condition is attained when the half angle that the incident beam subtends at the specimen, 𝛂 = (4𝛌/Cs)¼

Low-workfunction field-emission source for high-resolution EELS

1987 ◽  
Vol 45 ◽  
pp. 132-133
Author(s):  
P. E. Batson
Keyword(s):  
High Resolution ◽  
Energy Loss ◽  
Electron Probe ◽  
Collection Efficiency ◽  
Electron Sources ◽  
Wien Filter ◽  
Half Angle ◽  
Thermal Emitter ◽  
Electron Energy Loss ◽  
Intrinsic Energy

In recent years,instrumentation for electron energy loss spectroscopy (EELS) has been steadily improved to increase energy resolution and collection efficiency. At present 0.40eV at 10mR collection half angle is available with commercial magnetic sectors (e.g. Gatan, Inc. and VG Microscopes, Ltd.), and 70meV at 10mR has been demonstrated by use of a Wien filter within a large deceleration field. When these high resolution spectrometers are coupled to the modern small electron probe instrument, we obtain a tool which promises to reveal local changes in bandstructure and bonding near defects and interfaces in heterogeneous materials.Unfortunately, typical electron sources have intrinsic energy widths which limit attainable spectroscopic resolution in the absence of some monochromation system. For instance, the W thermal emitter has a half width of about 1eV.

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