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  • 1
    Electronic Resource
    Electronic Resource
    Phase separation induced by a chain polymerization: Polysulfone-modified epoxy/anhydride systems (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 36 (1998), S. 1349-1359 
    Details
    ISSN: 0887-6266
    Keywords: reaction-induced phase separation ; polysulfone-epoxy blends ; epoxy-anhydride networks ; polysulfone-modified epoxies ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reaction-induced phase separation in a blend of a commercial polysulfone (PSu) with diepoxide-cyclic anhydride monomers, was studied. The diepoxide was based on diglycidylether of bisphenol A (DGEBA) and the hardener was methyl tetrahydrophthalic anhydride (MTHPA), used in stoichiometric proportion. Benzyldimethylamine (BDMA) was used as initiator. PSu had no influence on the polymerization kinetics, the gel conversion, and the overall heat of reaction per epoxy equivalent. A kinetic model including initiation, propagation, and termination steps was used to estimate the distribution of linear and branched species in the first stages of the chain-wise copolymerization. This distribution, together with the PSu distribution, were taken into account in a thermodynamic model of the blend. The interaction parameter was fitted from experimental determinations of conversions at the start of phase separation, obtained under different conditions. The thermodynamic model was used to explain the complex morphologies developed in materials containing different PSu concentrations as well as their dynamic mechanical response. The shift in glass transition temperatures was explained by the fractionation of different species during the phase separation process. Phase inversion produced a significant decrease of the elastic modulus in the glassy state and a thermoplastic-like behavior of the material in the rubbery region. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1349-1359, 1998
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Some aspects of curing novolac with hexamethylenetetramine (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 311-318 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Curing novolac with hexamethylenetetramine in closed molds at T = 190°C was studied. Cured products were examined with the following experimental techniques: sol fraction determination, % N fixed in sol and gel fractions, and IR spectra. The fraction of fixed N decreased from 1 to 0.5 when the hexa mass fraction was increased from 0 to 0.3 in the mixture with novolacs. A segregation of the fixed N in the sol fraction was observed. Azomethine derivatives were present, their amounts increasing with the hexa mass fraction. Curing was described by a reaction scheme similar to the one derived from studies with model phenols. A simplified scheme was adequate for the prediction of the minimum hexa amount necessary to gel the system at full conversion.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170200205
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  • 3
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    Mining and beneficiation of lunar ores (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The beneficiation of lunar plagioclase and ilmenite ores to feedstock grade permits a rapid growth of the space manufacturing economy by maximizing the production rate of metals and oxygen. A beneficiation scheme based on electrostatic and magnetic separation is preferred over conventional schemes, but such a scheme cannot be completely modeled because beneficiation processes are empirical and because some properties of lunar minerals have not been measured. To meet anticipated shipping and processing needs, the peak lunar mining rate will exceed 1000 tons/hr by the fifth year of operation. Such capabilities will be best obtained by automated mining vehicles and conveyor systems rather than trucks. It may be possible to extract about 40 kg of volatiles (60 percent H2O) by thermally processing the less than 20 micron ilmenite concentrate extracted from 130 tons of ilmenite ore. A thermodynamic analysis of an extraction process is presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Resources and Space Settlements; p 275-288
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  • 4
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    A geologic assessment of potential lunar ores (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Although bulk lunar soil is not a suitable feedstock for extracting metals, certain minerals such as anorthite and ilmenite can be separated and concentrated. These minerals can be considered as potential ores of aluminum, silicon, titanium, andiron. A separation and metal extraction plant could also extract large amounts of oxygen and perhaps hydrogen from these minerals. Anorthie containing 19 percent aluminum and 20 percent silicon can be concentrated from some highland soils where it is present in amounts up to 60 percent. Ilmenite containing 32 percent titanium and 37 percent iron can be concentrated from some mare soils where it is present in amounts up to 10 percent. The ideal mining site would be located at the boundary between a high-titanium mare and a high-aluminum highlands. Such area may exist around the rims of some eastern maria, particularly Tranquilitatis. A location on Earth with raw materials as described above would be considered an economically valuable ore deposit if conventional terrestrial resources were not available.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA. Ames Res. Center Space Resources and Space Settlements; p 243-255
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  • 5
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    Report of Workshop on Methodology for Evaluating Potential Lunar Resources Sites (1981)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The type and quantity of lunar materials needed to support a space power satellite program was used to define the type and quality of geological information required to certify a site for exploitation. The existing geological, geochemical, and geophysical data are summarized. The difference between these data and the required data for exploitation is used to define program requirements. Most of these requirements involve linear extensions of existing capabilities, fuller utilization of existing data, or expanded use of automated systems.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-TM-58235 , JSC-17058 , Houston, TX; United States
    Format: application/pdf
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  • 6
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    Handbook of lunar materials (1980)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The physical, chemical, thermodynamic, and geologic data on lunar rocks, minerals, and processes are summarized, and a set of data metals that might be extracted from lunar materials is presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA-RP-1057
    Format: application/pdf
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  • 7
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    Experimentally reproduced textures and mineral chemistries of high-titanium mare basalts (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Many of the textures, morphologies, and mineral chemistries of the high-titanium mare basalts have been experimentally duplicated using single-stage cooling histories. Lunar high-titanium mare basalts are modeled in a 1 m thick gravitationally differentiating flow based on cooling rates, thermal models, and modal olivine contents. The low-pressure equilibrium phase relations of a synthetic high-titanium basalt composition were investigated as a function of oxygen fugacity, and petrographic criteria are developed for the recognition of phenocrysts which were present in the liquid at the time of eruption.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Science Conference; Mar 17, 1975 - Mar 21, 1975; Houston, TX
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  • 8
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    The system anorthite-forsterite-fayalite-silica to 2 kbar with lunar petrologic applications (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Near-liquidus phase relations in the magnesium-rich portion of the system anorthite-forsterite-fayalite-silica have been determined from synthesis experiments at 1 atm and 2 kbar at oxygen fugacities near the iron-wuestite buffer. The major-element chemistries of KREEP basalts are similar to peritectic liquids, L/ol,px,an/, produced experimentally. The reaction L/ol,px,an/ is well-located at low pressures. It intersects the join anorthite-enstatite-ferrosilite at Fe/(Fe+Mg) equals 0.45 (atomic ratio), and is peritectic only for Fe/(Fe+Mg) not greater than 0.45. Although positions of the equilibria, L/an,ol/ and L/ol,px/, differ significantly at 1 atm from their positions at 2 kbar, the position of the piercing point, L/ol,px,an/, on the anorthite-enstatite-ferrosilite join is not sensitive to pressure. The composition of liquids produced by partial melting of troctolites and pyroxenites in the lunar crustal environment will be affected by pressure, whereas liquids derived from gabbroic assemblages will not.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Science Conference; Mar 17, 1975 - Mar 21, 1975; Houston, TX
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  • 9
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    Experimental modeling of the cooling history of Apollo 12 olivine basalts (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: An analog of the Apollo 12 olivine vitrophyres has been crystallized in a 1-atm gas-mixing furnace at cooling rates ranging between 1250 and 0.7 C/hr and isothermally at degrees of supercooling ranging from 10 C to 325 C. Mineral chemistry, crystal shapes, grain sizes and textures are systematically related to cooling rate and degree of supercooling. At linear cooling rates not exceeding 40 C/hr the texture is porphyritic - large olivine crystals are set in a groundmass of finer-grained pyroxene, plagioclase, and ilmenite; a later generation of olivine never crystallizes. There are three shapes of olivine crystals in the Apollo 12 olivine vitrophyres: glomerocrysts of subhedral crystals, large subequant skeletons, and highly elongate skeletons. These result from three generations of nucleation and a two-stage cooling history - a slow preeruption stage and a rapid continuously increasing posteruption stage. It seems likely that the Apollo 12 olivine basalt magmas were erupted with olivine crystals in suspension. The nucleation temperature of olivine in cooling-rate experiments is dependent on the experimental technique, and hence results of cooling experiments should be applied with caution.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Science Conference; Mar 17, 1975 - Mar 21, 1975; Houston, TX
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  • 10
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    Experimentally reproduced textures and mineral chemistry of Apollo 15 quartz normative basalts (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Lunar Science Conference; Mar 18, 1974 - Mar 22, 1974; Houston, TX
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