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  • Aircraft Design, Testing and Performance  (1)
  • Hamster  (1)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 19 (1991), S. 406-418 
    ISSN: 0741-0581
    Keywords: Vascular corrosion casting ; Emphysema ; Vasculature ; Elastase ; Hamster ; Lung ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Vascular corrosion casts of normal and elastase-induced emphysemic hamster lungs, prepared with a low viscosity resin mixture consisting of Mercox and Sevriton, were observed by scanning electron microscopy. Casts were quantitated by measuring vascular volume or determining non-alveolar air space using confocal laser scanning microscopy. Normal lung casts were characterized by well-organized fields of alveoli (about 70 μm in diameter) connected by distinct alveolar ducts. Emphysemic lung casts exhibited numerous bullae (often as large as 0.5 mm in diameter). The vasculature of the bullae indicated that they were formed by destruction of alveolar walls and subsequent coalescence of numerous alveolae. Remnants of alveolar walls, consisting of shallow ridges of capillaries, lined the bases of the bullae. Vascular volumes expressed as cast volume/total tissue volume were calculated at 20% and 12% for uninflated and inflated lungs, respectively, for both control and emphysemic lungs. Four months after elastase instillation, non-alveolar air space of the emphysemic lungs was increased by 73% over controls. These observations indicate that elastase emphysema results, initially, in remodeling of the alveolar structure (bullae formation) and loss of surface area for gas exchange, rather than from extensive loss of vasculature. Vascular corrosion casting is a useful technique for monitoring emphysema both morphologically and quantitatively.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2019-08-17
    Description: As part of an investigation to increase the power output of the V-1710-93 engine at altitude, the engine-stage supercharger was combined with a constant-area vaneless diffuser designed to improve the performance of the engine-stage supercharger at the rated engine operating point. The performance of the modified supercharger was investigated in a variable-component supercharger test rig and compared with that of the standard supercharger with an 8-vaned diffuser. A separate evaluation of the component efficiencies and a study of the flow characteristics of the modified supercharger was made possible by internal diffuser instrumentation. At the volume flow required by the engine for rated operating conditions, the modified supercharger increased the over-all adiabatic efficiency 0.05 and the over-all pressure coefficient 0.035. Furthermore, the capacity of the engine-stage supercharger was increased by replacing the standard 8-vaned diffuser with the vaneless diffuser. The peak over-all adiabatic efficiency for the modified supercharger, however, was 0.05 to 0.07 lower than that of the standard unit over the range of tip speeds investigated. The improved performance of the modified supercharger at rated engine operating conditions resulted from a shift of the point of peak adiabatic efficiency and pressure coefficient of the standard supercharger to a higher flow. The energy loss through the vaneless diffuser was found to be small. Because of the restricted diffuser diameter, however, diffusion was inadequate, which resulted in a relatively small static-pressure rise through the diffuser, high diffuser-exit velocities, and excessive collector-case losses.
    Keywords: Aircraft Design, Testing and Performance
    Type: NACA-RM-E6K22
    Format: application/pdf
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