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  • FLUID MECHANICS AND HEAT TRANSFER  (68)
  • LIFE SCIENCES (GENERAL)  (51)
  • 1980-1984  (119)
  • 1982  (119)
  • 1
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    Effect of space flight on bone strength (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: To test the possibility that spaceflight has a deleterious effect on bone mechanical properties, femur breaking strength by torsional loading in rats that had been flown for 19 days aboard Cosmos 936 was determined. The results showed that femurs from flight rats were less stiff than the flight controls, and failed under torsion at a lower torque and energy of absorption. The defect was corrected following space flight and could be prevented during space flight by centrifuging the rats at 1 x g. Altered bone geometry due to inhibition of bone formation at the periosteal surface provides the most likely explanation for the decrease in bone strength during spaceflight.
    Keywords: LIFE SCIENCES (GENERAL)
    Type: p. S-75
    Format: text
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  • 2
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    Mean flowfields in axisymmetric combustor geometries with swirl (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Six flowfield configurations are investigated with sidewall angles of 90 and 45 deg, and swirl vane angles of 0, 45, and 70 deg. It is found that central recirculation zones occur for the swirling flow cases investigated, which extend from the inlet to x/D = 1.7, where x is the axial polar coordinate, and D is the test section diameter. Five-hole pitot probe pressure measurements are used to determine time-mean velocities, and corresponding flow situations are predicted and compared to results of experimental data. Excellent agreement is found for the nonswirling flow, although poor agreement is found for swirling flow cases, especially near the inlet. The discrepancy is attributed to the lack of realism in the turbulence model, and/or to inaccurate specification of time-mean velocity and turbulence energy distributions at the inlet.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA PAPER 82-0177 , Aerospace Sciences Meeting; Jan 11, 1982 - Jan 14, 1982; Orlando, FL
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    NASA TECHNICAL REPORTS
  • 3
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    Effects of hypergravity on rat liver regeneration (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The effects of centrifugation on liver regrowth were examined by measuring mitotic activity. The results indicate that the increased gravity caused a delay in the onset of mitotic activity and a significant decrease in overall mitotic activity.
    Keywords: LIFE SCIENCES (GENERAL)
    Type: Space Gerontology; p 53-54
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  • 4
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    Evidence for arrested bone formation during spaceflight (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Addressing the question of whether the bone formed in space is unusual, the morphology of bone made at the tibial diaphysis of rats before, during, and after spaceflight is studied. Evidence of arrest lines in the bone formed in space is reported suggesting that bone formation ceases along portions of the periosteum during spaceflight. Visualized by microradiography, the arrest lines are shown to be less mineralized than the surrounding bone matrix. When viewed by scanning electron microscopy, it is seen that bone fractures more readily at the site of an arrest line. These observations are seen as suggesting that arrest lines are a zone of weakness and that their formation may result in decreased bone strength in spite of normalization of bone formation after flight. The occurrence, location, and morphology of arrest lines are seen as suggesting that they are a visible result of the phenomenon of arrested bone formation.
    Keywords: LIFE SCIENCES (GENERAL)
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  • 5
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    Atrophy of rat skeletal muscles in simulated weightlessness (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A hypokinetic rat model was used for elucidation of the mechanism of skeletal muscle wasting which occurs in weightlessness. Rats were suspended from a back-harness with the head tilted downward and the hind limbs totally unloaded. A progressive decrease in the size of the soleus muscle from suspended rats was observed as a function of time. The rate of protein degradation of the homogenates from the soleus muscles of suspended and control animals was not significantly different. The rate of cell-free protein synthesis was severely repressed in the atrophied muscle. An initial rise in the levels of plasma glucose and corticosterone was observed on the second day of suspension, but they subsequently returned to normal values.
    Keywords: LIFE SCIENCES (GENERAL)
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  • 6
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    Calcium transport from the intestine and into bone in a rat model simulating weightlessness (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The objective of this study was to determine whether a defect in transport of calcium in the duodenum was related to decreased bone formation in the suspended rat. Rats were suspended by the tail at a 40 deg angle for up to 15 days. Ca-45 was injected into the ligated duodenum in situ 15 minutes prior to sacrific. Blood, tibia, vertebra and humerus were obtained for total calcium and Ca-45 analyses. Intestinal calcium transport did not appear to be significantly altered by suspension. However, by 5 days of suspension a significant decrease in accumulation of Ca-45 into tibia and vertebra was observed. A trend of decreasing bone mineral and mass was established in tibia and vertebra by the fifth day of suspension. The humerus failed to demonstrate a significant weight decrease or change in Ca-45 accumulation after 15 days of suspension. Results from this simulated weightlessness model suggest that transport of calcium from intestine into bone is decreased within 5 days of suspension. This deficiency appears to be associated with a progressive decrease in total mass of non-weightbearing bones.
    Keywords: LIFE SCIENCES (GENERAL)
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  • 7
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    Space Shuttle orbiter entry heating and TPS response: STS-1 predictions and flight data (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Aerothermodynamic development flight test data from the first orbital flight test of the Space Transportation System (STS) transmitted after entry blackout is given. Engineering predictions of boundary layer transition and numerical simulations of the orbiter flow field were confirmed. The data tended to substantiate preflight predictions of surface catalysis phenomena. The thermal response of the thermal protection system was as expected. The only exception is that internal free convection was found to be significant in limiting the peak temperature of the structure in areas which do not have internal insulation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Langley Research Center Computational Aspects of Heat Transfer in Struct.; p 327-347
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  • 8
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    Normal modes of a compound drop (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The modes are characterized by their frequency, the attendant displacement of fluid boundaries, and the flow pressure fields within the fluids. The drops consist of three fluids; a core fluid, a fluid shell surrounding the core, and a host fluid surrounding the shell. These fluids are assumed to be inviscid and incompressible, and the core and the shell to be concentric. The theory is obtained by linearization of the equations of fluid motion to the lowest order of nonlinearity that yields the normal modes. Numerical values of mode frequencies and the associated relative displacements of the fluid boundaries are presented for several specific systems, and the results compared with observations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 7-14
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  • 9
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    Generation of a strong core centering force in a submillimeter compound droplet system (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: By amplitude-modulating the driving voltage of an acoustic levitating apparatus, a strong core centering force was generated in a submillimeter compound droplet system suspended by the radiation pressure in a gaseous medium. Depending on the acoustic characteristics of the droplet system, it was found that the technique can be utilized advantageously in the multiple-layer coating of an inertial confinement fusion pellet.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 107-111
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  • 10
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    Acoustically induced oscillation and rotation of a large drop in space (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: A 2.5 cm diameter water drop was successfully deployed and manipulated in a triaxial acoustic resonance chamber during a 240 sec low-gravity SPAR rocket flight. Oscillation and rotation were induced by modulating and phase shifting the signals to the speakers. Portions of the film record were digitized and analyzed. Spectral analysis brought out the n = 2, 3, 4 free oscillation modes of the drop, its very low-frequency center-of-mass motion in the acoustic potential well, and the forced oscillation frequency. The drop boundaries were least-square fitted to general ellipses, providing eccentricities of the distorted drop. The normalized equatorial area of the rotating drop was plotted vs a rotational parameter, and was in excellent agreement with values derived from the theory of equilibrium shapes of rotating liquid drops.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Proc. of the 2d Intern. Colloq. on Drops and Bubbles; p 31-38
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