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  • 1
    Electronic Resource
    Electronic Resource
    Petrology of gabbroic xenoliths in 1960 Kilauea basalt: crystalline remnants of prior (1955) magmatism (1994)
    Springer
    Bulletin of volcanology 56 (1994), S. 62-74 
    Details
    ISSN: 1432-0819
    Keywords: basalt ; gabbro ; xenolith ; Kilauea ; basalt crystallization ; basalt phases ; cumulate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The 1960 Kapoho lavas of Kilauea's east rift zone contain 1–10 cm xenoliths of olivine gabbro, olivine gabbro-norite, and gabbro norite. Textures are poikilitic (ol+sp+cpx in pl) and intergranular (cpx+pl±ol±opx). Poikilitic xenoliths, which we interpret as cumulates, have the most primitive mineral compositions, Fo82.5, cpx Mg# 86.5, and An80.5. Many granular xenoliths (ol and noritic gabbro) contain abundant vesicular glass that gives them intersertal, hyaloophitic, and overall ‘open’ textures to suggest that they represent ‘mush’ and ‘crust’ of a magma crystallization environment. Their phase compositions are more evolved (Fo80-70, cpx Mg# 82-75, and An73-63) than those of the poikilitic xenoliths. Associated glass is basaltic, but evolved (MgO 5 wt%; TiO2 3.7–5.8 wt%). The gabbroic xenolith mineral compositions fit existing fractional crystallization models that relate the origins of various Kilauea lavas to one another. FeO/MgO crystal-liquid partitioning is consistent with the poikilitic ol-gabbro assemblage forming as a crystallization product from Kilauea summit magma with ∼8 wt% MgO that was parental to evolved lavas on the east rift zone. For example, least squares calculations link summit magmas to early 1955 rift-zone lavas (∼5 wt% MgO) through ∼28–34% crystallization of the ol+sp+cpx+pl that comprise the poikilitic ol-gabbros. The other ol-gabbro assemblages and the olivine gabbro-norite assemblages crystallized from evolved liquids, such as represented by the early 1955 and late 1955 lavas (∼6.5 wt% MgO) of the east rift zone. The eruption of 1960 Kapoho magmas, then, scoured the rift-zone reservoir system to entrain portions of cumulate and solidification zones that had coated reservoir margins during crystallization of prior east rift-zone magmas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279729
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Asymmetric nafion/(zirconium oxide) hybrid membranes via in situ sol-gel chemistry (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 62 (1996), S. 417-426 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Nafion-in situ sol-gel reactions were affected for Zr(OBu)4 that permeated low water content membranes unidirectionally. IR peaks reflecting ZrO2 and incomplete hydrolysis of ZrOBu groups near both surfaces were detected. Vibrations of Zr(OEt)4 detected near both sides arise from alkoxy exchange in the presence of the solvent EtOH. Unreacted alkoxy group bands are more distinct near the nonpermeated surface. An IR band for the ZnOBu group diminishes, whereas that for ZnOEt increases with increasing time near the permeated surface due to progressive alkoxy exchange. The ZrO2 band becomes more intense with time near the permeated surface. X-ray spectroscopy/scanning electron microscopy studies of Zr concentration across the membrane thickness verified compositional asymmetry. CO2 gas permeability versus upstream pressure plots are monotonically increasing, suggesting diffusion accompanied by complex plasticization. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    [Perfluorosulfonate ionomer]/[SiO2-TiO2] nanocomposites via polymer-in situ sol-gel chemistry: Sequential alkoxide procedure (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 34 (1996), S. 873-882 
    Details
    ISSN: 0887-6266
    Keywords: perfluorosulfonate ionomer ; sol-gel reaction ; silica/titania core-shell ; nanocomposite ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In situ sol-gel chemistry was used to create inorganic/perfluoro-organic hybrids wherein titanium oxide outer regions of SiO2[1 - x/4](OH)x nanoparticles, which were preformed in Nafion® membranes, were created by postreaction with tetrabutyltitanate (TBT). U-shaped Si and Ti distributions across the membrane thickness direction were determined via x-ray energy dispersive spectroscopy. Ti/Si ratio profiles are also U-shaped, indicating more Ti relative to Si in near-surface regions. IR spectroscopy verified structural bonding of TiO4 units onto SiO2 nanoparticles and indicated that alkoxide hydrolysis is not complete. Reacted silicon oxide nanophases retain the topological unconnectedness possessed by the corresponding unreacted phase. IR bands signifying molecular loops and linear fragments of Si(SINGLE BOND)O(SINGLE BOND)Si groups are seen. 29Si solid-state NMR spectroscopy indicated that, for an inorganic uptake of 16.3 wt %, the Q3 state of SiO4 is most populated although Q4 is only slightly less prominent and Q2 and Q1 are either small or absent. The silicon oxide component, although not being predominantly linear, retains a measure of uncondensed SiOH groups. Tensile stress vs. strain analyses suggested that TBT postreaction links nanoparticles, causing them to be contiguous over considerable distances. This percolative intergrowth occurs in near-surface regions generating a glassy zone. © 1996 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Small-angle X-ray scattering studies of Nafion®/[silicon oxide] and Nafion®/ORMOSIL nanocomposites (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 34 (1996), S. 1917-1923 
    Details
    ISSN: 0887-6266
    Keywords: SAXS ; Nafion® ; ORMOSIL ; sol-gel reaction ; nanocomposite ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The small angle X-ray scattering technique was used to probe structural heterogeneity on the scale of nanometers within Nafion®/[silicon oxide], Nafion®/[ORMOSIL], and Nafion®/[dimethylsiloxane] hybrid membranes. The results of this study reinforced the working hypothesis of morphological template action for the in situ growth of silicon oxide, or organically modified silicon oxide phases in perfluorosulfonate ionomers via sol-gel reactions for silicon alkoxide or/and silicon alkylalkoxide precursors. Nanophase separation persists when incorporated silicon oxide particles are postreacted with ethoxytrimethylsilane but postreaction with diethoxydimethylsilane generates co-continuous phases that do not generate ionomer SAXS peaks, presumably due to a more homogeneous Si atom distribution within the ionomer. These hybrids are true nanocomposites, as structural heterogeneity exists on the scale of ∼ 5 nm. The variation of the small angle upturn for these hybrids is explained in terms of long-range inhomogeneities in ionomers. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Asymmetric [Nafion®]/[silicon oxide] hybrid membranes via the in situ sol-gel reaction for tetraethoxysilane (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 34 (1996), S. 2383-2392 
    Details
    ISSN: 0887-6266
    Keywords: asymmetric membranes ; Nafion® ; silicon oxide ; sol-gel reaction ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Asymmetric silicon oxide composition profiles along a direction perpendicular to the plane of Nafion® sulfonate films were created via in situ sol-gel reactions for one-sided tetraethoxysilane permeation, as verified by EDAX/ESEM. For K+ form membranes, we propose the existence of an IR spectral signature of molecular branches in addition to those characteristic of linear and cyclic fragments in the silicon oxide phase. The molecular structure of the silicon oxide phase is more interconnected than linear in K+ form membranes. For H+ form membranes, there appears to be an increasing degree of molecular linearity within the silicon oxide phase with increasing uptake. IR spectra indicate that molecular connectivity on the permeated side is lower, on the average, than that on the nonpermeated side. The inverse relationship between gas permeability and upstream pressure in steady-state helium gas transmission experiments suggests the dual-mode sorption of gases, which is in harmony with the multiphasic nature of these membranes. © 1996 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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