13,005 research outputs found
Stephen F. Austin Eagle, 1981-82, Volume 34
No full textYearbook for Stephen F. Austin High School in Port Arthur, Texas includes photographs of and information about the school, student body, teachers, and organizations. The index begins on page 203
Service-oriented models for audiovisual content storage
No full textWhat are the important topics to understand if involved with storage services to hold digital audiovisual content? This report takes a look at how content is created and moves into and out of storage; the storage service value networks and architectures found now and expected in the future; what sort of data transfer is expected to and from an audiovisual archive; what transfer protocols to use; and a summary of security and interface issues
Aaron Foley talks about his relationship with Detroit
No full textAaron Foley speaks about his relationship with Detroit for Marcus Lyon's i.Detroit project. Foley explains how he came into his role as Detroit's storyteller, and the importance of Detroit as a community
Stephen F. Austin Eagle, 1980, Volume 32
No full textYearbook for Stephen F. Austin High School in Port Arthur, Texas includes photographs of and information about the school, student body, teachers, and organizations
Phase relations and fractionation sequences in potassic magma series modelled in the system CaMgSi2O6-KAlSiO4-Mg2SiO4SiO2-F2O-1 at 1 bar to 18 kbar
No full textLiquidus phase relations in the system diopside-kalsilite-forsterite-quartz with 3 wt% F were examined at 1 bar and the locations of important invariant points were determined at 18 kbar. At all pressures within this range a large liquidus field for fluorphlogopite (Phl) exists, and has a large influence on both melting and fractionation processes. One eutectic point was found to the silica-rich side of the plane Lc-Fo-Di at Di(1)Ks(30)Fo(2)Qz(67), where a melt coexists with San, Qz, Phl and Di at 840 degrees C and 1 bar. Another eutectic point must exist in the silica-poor part of the system because the phase topology determines that thermal barriers must exist. At this point a feldspathoid, either Lc or Ks, must coexist with Fo, Phl and a Ca-bearing phase such as Di. The exact location and phase assemblage were not determined, but the equilibrium melt must have a composition rich in Di (>29 wt%) and extremely poor in Qz (<8 wt%). The composition of the first eutectic moves towards lower SiO2 contents with increasing pressure (Di(3)Ks(40)Fo(1)Qz(56) at 18 kbar), whereas the second does not exist at 18 kbar due to the disappearance of Lc as a stable liquidus phase. Liquids which coexist with mafic minerals such as En, Fo, Phl and Di are important for the genesis of potassium-rich mafic rocks by partial melting in the mantle and for the early stages of fractional crystallisation. The equilibrium melt at the invariant point Fo + En + Phl + Di + L at 1125 degrees C is very poor in Fo and Di components at atmospheric pressure (Di(5)Ks(37)Fo(5)Qz(53)), whereas at Is kbar the melt contains large amounts of Fo and Di (Di(19)Ks(31)Fo(28)Qz(21)), and has a composition close to that of natural lamproites. Kamafugites do not correspond to melts in this system under any of the studied conditions, and appear to require CO2 in the source. Fractionation processes from primitive: potassic basanite melts are controlled principally by the size (and not the mere presence) of the liquidus phase field for phlogopite: at high pressures where the Phl field is large, olivine is eliminated early from the fractionating assemblage and Cpx + Phl fractionation may lead to relatively silica-rich rock differentiates such as trachytes. At low pressures, extensive olivine and restricted Phl crystallisation prevents silica enrichment in the melt, resulting in phonolitic differentiates. Later crystallisation of alkali feldspar accentuates the trends laid down in the early stages of fractionation
AC-6-U.S. Naval Planes Flying in Formation, Langley Field, VA/Thank-You Card from Stephen Tury to the Hungarian Defense Council.
No full textThis postcard, which depicts U.S. Naval planes flying in formation, was sent to the Hungarian Defense Council by Private Stephen Tury. The Council was organized in New Brunswick by leaders of local Hungarian churches and societies. During the Second World War it sent supplies, such as the carton of cigarettes Tury is thanking it for, to members of the military of Hungarian descent from the New Brunswick area
Trace element and Nd–Sr isotopic composition of ultramafic lamprophyres from the East Antarctic Beaver Lake area
No full textThe trace element and Nd-Sr isotopic compositions of Cretaceous (110-117 Ma) ultramafic lamprophyres from the Beaver Lake area in East Antarctica, which are developed as sill, dyke and plug intrusions. have been investigated. Rare earth elements of lamprophyres are strongly fractionated, with LREE > 100 times chondrite, whereas HREE are < 10 times chondrite, presumably indicating the presence of residual garnet in the source region. A characteristic feature of the Beaver Lake rocks is low concentrations of Zr and Hf (Zr, 50-150 ppm: Hf, 1.0-5.0 ppm) and to a lesser extent Nb (17-90 ppm) which cause strong negative anomalies in the normalized trace element patterns. Eruption age-corrected Nd isotope values vary within narrow ranges (epsilon Nd-(t) = + 2.1 to + 4.3), whereas Sr isotope values show more variation (Sr-87/Sr-86((t)) = 0.704336-0.706431), similar to the isotopic compositions of other ultramafic lamprophyres. The genesis of the ultramafic lamprophyres is explained as a result of the gradual widening of the Lambert-Amery rift during the Phanerozoic. An increase in the geothermal gradient from cold continental conditions beneath the Archean block to the west may have resulted in grazing of the peridotite solidus at depths greater than 110 km. The initial carbonate-rich melts migrated upwards and froze as carbonate-bearing veins in the overlying lithosphere. Later upward and outward migration of the asthenosphere beneath the rift caused remelting of the veined region, resulting in melts of ultramafic lamprophyre composition with a mixed geochemical abundance and isotope signature from carbonate-rich veins and depleted peridotite wall-rock. The CO2-rich component of the lamprophyres is derived principally from the vein assemblage, from which phlogopite gives rise to the variable Sr isotopes, and baddeleyite to the differing Zr and Hf abundances. The difference between the lamprophyre facies of the Beaver Lake intrusions can be explained by minor amounts of olivine and Cr-spinel fractionation. (C) 2001 Elsevier Science B.V, All rights reserved
Author Stephen Flynn Discusses Resiliency
No full textCenter for Homeland Defense and Security, PRESS RELEASESOn September 25, Author Stephen E. Flynn stopped by the Center’s National Capital Region campus to speak with CHDS Master’s degree students about his latest book, answer questions and discuss..
The effect of crystal orientation on the wetting behaviour of silicate melts on the surfaces of spinel peridotite minerals
No full textThe effect of crystal anisotropy on wetting angles of equilibrium silicate melts on crystal faces of spinet, diopside. enstatite and olivine has been determined experimentally by the sessile melt drop technique. The anisotropy (A) over tilde gamma(SL), of solid-liquid interfacial energies (gamma(SL) (max')-gamma(SL) (min)) can be related to the wetting angles, psi, by (A) over tilde gamma(SL) proportional to \cos psi (max) - cos psi (min)\ = Pw ((A) over tilde gamma(SL)). Normalising to the smallest wetting angle gives values of P-w for diopside = 0.0728, olivine = 0.0574, orthopyroxene=0.01521, and spinel=0.0075. Crystal anisotropy influences grain-scale morphology of small-degree partial melts. permeability and the melt connectivity threshold, phi(c). Results show that, at sufficient melt fractions. diopside should increase permeability in a peridotitic matrix, whereas enstatite should lower it. Despite its low anisotropy, spinet contributes positively to permeability and phi(c) because of its high surface energies. These results suggest that harzburgitic mineral matrices typical of the suberatonic mantle should impede the movement of low-degree partial melts, whereas melts should flow more easily through spinet lherzolites
Cs-Rb-Ba systematics in phengite and amphibole: an assessment of fluid mobility at 2.0 GPa in eclogites from Trescolmen, Central Alps
No full textEclogites from Trescolmen that contain abundant hydrous minerals (phengite, amphibole, paragonite, zoisite, talc, apatite) show petrographic evidence for fluid infiltration under conditions of 2.0 to 1.8 GPa, 650 degreesC. Large ion lithophile elements (LILE, e.g. Cs, Rb, Ba and Sr) were analysed by in-situ techniques in all eclogite mineral phases in order to characterize the behaviour of fluid-mobile elements at high pressure. In-situ analysis of carefully-chosen metamorphic assemblages circumvents the problem of partial late-stage alteration, which can severely influence the calculated element budgets of whole-rock samples. Phengite is the dominant host for Cs, Rb, and Ba in both eclogite and adjacent garnet mica schist samples, and incorporates > 90% of the budgets of these elements in whole rocks. LILE contents of phengites in phengite-rich rocks are likely to record the Cs/Rb and Ba/Rb ratios of their host rock protoliths. The LILE patterns of eclogite are consistent with protoliths derived from basalt that underwent seafloor alteration, whereas those of mica schist are almost identical to average upper continental crust. In contrast, LILE patterns of eclogite samples that lack phengite, but do contain amphibole, are unlike any plausible protolith, but are identical to those of amphibole in phengite-bearing samples. This observation points to homogenization of the LILE in different lithologies, which we correlate with petrographic evidence for fluid infiltration. Because phengite in garnet mica schist has a strong capacity to buffer the fluid with respect to Cs, Rb, and Ba, homogenization of amphiboles is best explained by fluid infiltration from the surrounding metapelites into eclogite bodies, implying at least metre-scale fluid mobility. The amphibole homogenization can be most easily modelled by a pervasive open-system fluid flux through the eclogites, possibly facilitated by ductile deformation during the early stages of uplift. Simple calculations give minimum fluid-rock ratios of similar to0.001 to 0.004. Demonstration of the mobility of very small volumes of fluid through eclogite is an important prerequisite of many subduction zone models that try to explain across-are variations in trace element geochemistry. The low fluid-rock ratios from this study are not in contrast with oxygen isotope heterogeneities reported from other eclogite localities. Fluid mobile elements such as Cs, Rb and Ba are more sensitive indicators of small volume, fluid-rock interaction and are therefore potentially valuable for understanding fluid infiltration processes in systems where oxygen isotope shifts are not large enough to be detectable
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