ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Space Sciences (General)  (2)
  • 1,3-dioxane and 1,4-dioxane  (1)
  • 1
    ISSN: 1572-8927
    Keywords: Freezing points ; enthalpies ; aqueous solutions ; Gibbs energy ; tetrahydropyran ; 1,3-dioxane and 1,4-dioxane ; 1,3,5-trioxane ; solute-solute interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The enthalpies of dilute aqueous solutions of tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 1,2,5-trioxane, and an equimolal mixture of tetrahydropyran and 1,3,5-trioxane were measured at 25°C and at molalities from about 0.1 to 1.0 mol kg1. The freezing points of the same aqueous solutions (except for 1,3-dioxane) were measured over a similar molality range. The results were used to calculate the enthalpies and Gibbs free energies of the pair-wise interactions of the above solutes in dilute aqueous solutions at 25°C. From these results, the additivity principle proposed by Savage and Wood was used to get the Gibbs free energy and enthalpies of interaction for the ether-ether and ether-methylene groups. Because of the limited number of measurements, the interaction parameters were not determined with great precision. Nevertheless, the standard errors for the predicted enthalpies and Gibbs free energies are quite reasonable. The signs and magnitudes are similiar to those determined for other polar groups.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2018-06-06
    Description: Previous work by our group has shown that an aerogravity assist maneuver at the moon Titan could be used to capture a spacecraft into a closed orbit about Saturn if a nominal atmospheric profile at Titan is assumed. The present study extends that work and examines the impact of atmospheric dispersions, variations in the final target orbit and low density aerodynamics on the aerocapture maneuver. Accounting for atmospheric dispersions substantially reduces the entry corridor width for a blunt configuration with a lift-to-drag ratio of 0.25. Moreover, the choice of the outbound hyperbolic excess speed (with respect to Titan) strongly influences the corridor width. Given the influence of these two parameters, certain mission scenarios may be feasible using a blunt aeroshell, while other mission designs would likely require a biconic vehicle with a higher lift-to-drag ratio. Preliminary simulations indicate that the same technique may be feasible for capture into orbit about Neptune using the tenuous atmosphere of Triton.
    Keywords: Space Sciences (General)
    Type: 2nd International Planetary Probe Workshop; 49-57; NASA/CP-2004-213456
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2019-07-13
    Description: Previous work by our group has shown that an aerogravity assist maneuver at the moon Triton might be used to capture a spacecraft into a closed orbit about Neptune if a nominal atmospheric density profile at Triton is assumed. The present study extends that work and examines the impact of atmospheric dispersions, especially important in light of the very low density and large degree of uncertainty of Triton s atmosphere. Additional variables that are analyzed in the current study include ballute size and cut time and variations in the final target orbit. Results indicate that while blunt-body, rigid aeroshells penetrate too closely to the surface to be practical, ballutes of modest size show promise for this maneuver. Future studies will examine the application of inflatable aeroshells and rigid aeroshells with higher lift-to-drag ratios such as biconics and lifting bodies.
    Keywords: Space Sciences (General)
    Type: 3rd International Planetary Proe Workshop (IPPW-3); Jun 27, 2005 - Jul 01, 2005; Anavyssos; Greece
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...