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Sample records for volcanic glass extracted

  1. Water in volcanic glass: From volcanic degassing to secondary hydration

    Science.gov (United States)

    Seligman, Angela N.; Bindeman, Ilya N.; Watkins, James M.; Ross, Abigail M.

    2016-10-01

    Volcanic glass is deposited with trace amounts (0.1-0.6 wt.%) of undegassed magmatic water dissolved in the glass. After deposition, meteoric water penetrates into the glass structure mostly as molecular H2O. Due to the lower δD (‰) values of non-tropical meteoric waters and the ∼30‰ offset between volcanic glass and environmental water during hydration, secondary water imparts lighter hydrogen isotopic values during secondary hydration up to a saturation concentration of 3-4 wt.% H2O. We analyzed compositionally and globally diverse volcanic glass from 0 to 10 ka for their δD and H2Ot across different climatic zones, and thus different δD of precipitation, on a thermal conversion elemental analyzer (TCEA) furnace attached to a mass spectrometer. We find that tephrachronologically coeval rhyolite glass is hydrated faster than basaltic glass, and in the majority of glasses an increase in age and total water content leads to a decrease in δD (‰), while a few equatorial glasses have little change in δD (‰). We compute a magmatic water correction based on our non-hydrated glasses, and calculate an average 103lnαglass-water for our hydrated felsic glasses of -33‰, which is similar to the 103lnαglass-water determined by Friedman et al. (1993a) of -34‰. We also determine a smaller average 103lnαglass-water for all our mafic glasses of -23‰. We compare the δD values of water extracted from our glasses to local meteoric waters following the inclusion of a -33‰ 103lnαglass-water. We find that, following a correction for residual magmatic water based on an average δD and wt.% H2Ot of recently erupted ashes from our study, the δD value of water extracted from hydrated volcanic glass is, on average, within 4‰ of local meteoric water. To better understand the difference in hydration rates of mafic and felsic glasses, we imaged 6 tephra clasts ranging in age and chemical composition with BSE (by FEI SEM) down to a submicron resolution. Mafic tephra

  2. Volcanic glasses, their origins and alteration processes

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    Friedman, I.; Long, W.

    1984-01-01

    Natural glass can be formed by volcanic processes, lightning (fulgarites) burning coal, and by meteorite impact. By far the most common process is volcanic - basically the glass is rapidly chilled molten rock. All natural glasses are thermodynamically unstable and tend to alter chemically or to crystallize. The rate of these processes is determined by the chemical composition of the magma. The hot and fluid basaltic melts have a structure that allows for rapid crystal growth, and seldom forms glass selvages greater than a few centimeters thick, even when the melt is rapidly cooled by extrusion in the deep sea. In contrast the cooler and very viscous rhyolitic magmas can yield bodies of glass that are tens of meters thick. These highly polymerized magmas have a high silica content - often 71-77% SiO2. Their high viscosity inhibits diffusive crystal growth. Basalt glass in sea water forms an alteration zone called palagonite whose thickness increases linearly with time. The rate of diffusion of water into rhyolitic glass, which follows the relationship - thickness = k (time) 1 2, has been determined as a function of the glass composition and temperature. Increased SiO2 increases the rate, whereas increased CaO, MgO and H2O decrease the rate. The activation energy of water diffusion varies from about 19 to 22 kcal/mol. for the glasses studied. The diffusion of alkali out of rhyolite glass occurs simultaneously with water diffusion into the glass. The rate of devitrification of rhyolitic glass is a function of the glass viscosity, which in turn is a function of water content and temperature. Although all of the aforementioned processes tend to destroy natural glasses, the slow rates of these processes, particularly for rhyolitic glass, has allowed samples of glass to persist for 60 million years. ?? 1984.

  3. Organic Entrainment and Preservation in Volcanic Glasses

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    Wilhelm, Mary Beth; Ojha, Lujendra; Brunner, Anna E.; Dufek, Josef D.; Wray, James Joseph

    2014-01-01

    Unaltered pyroclastic deposits have previously been deemed to have "low" potential for the formation, concentration and preservation of organic material on the Martian surface. Yet volcanic glasses that have solidified very quickly after an eruption may be good candidates for containment and preservation of refractory organic material that existed in a biologic system pre-eruption due to their impermeability and ability to attenuate UV radiation. Analysis using NanoSIMS of volcanic glass could then be performed to both deduce carbon isotope ratios that indicate biologic origin and confirm entrainment during eruption. Terrestrial contamination is one of the biggest barriers to definitive Martian organic identification in soil and rock samples. While there is a greater potential to concentrate organics in sedimentary strata, volcanic glasses may better encapsulate and preserve organics over long time scales, and are widespread on Mars. If volcanic glass from many sites on Earth could be shown to contain biologically derived organics from the original environment, there could be significant implications for the search for biomarkers in ancient Martian environments.

  4. Paleoarchean trace fossils in altered volcanic glass

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    Staudigel, Hubert; Furnes, Harald; DeWit, Maarten

    2015-01-01

    Microbial corrosion textures in volcanic glass from Cenozoic seafloor basalts and the corresponding titanite replacement microtextures in metamorphosed Paleoarchean pillow lavas have been interpreted as evidence for a deep biosphere dating back in time through the earliest periods of preserved life on earth. This interpretation has been recently challenged for Paleoarchean titanite replacement textures based on textural and geochronological data from pillow lavas in the Hooggenoeg Complex of the Barberton Greenstone Belt in South Africa. We use this controversy to explore the strengths and weaknesses of arguments made in support or rejection of the biogenicity interpretation of bioalteration trace fossils in Cenozoic basalt glasses and their putative equivalents in Paleoarchean greenstones. Our analysis suggests that biogenicity cannot be taken for granted for all titanite-based textures in metamorphosed basalt glass, but a cautious and critical evaluation of evidence suggests that biogenicity remains the most likely interpretation for previously described titanite microtextures in Paleoarchean pillow lavas. PMID:26038543

  5. Paleoarchean trace fossils in altered volcanic glass.

    Science.gov (United States)

    Staudigel, Hubert; Furnes, Harald; DeWit, Maarten

    2015-06-02

    Microbial corrosion textures in volcanic glass from Cenozoic seafloor basalts and the corresponding titanite replacement microtextures in metamorphosed Paleoarchean pillow lavas have been interpreted as evidence for a deep biosphere dating back in time through the earliest periods of preserved life on earth. This interpretation has been recently challenged for Paleoarchean titanite replacement textures based on textural and geochronological data from pillow lavas in the Hooggenoeg Complex of the Barberton Greenstone Belt in South Africa. We use this controversy to explore the strengths and weaknesses of arguments made in support or rejection of the biogenicity interpretation of bioalteration trace fossils in Cenozoic basalt glasses and their putative equivalents in Paleoarchean greenstones. Our analysis suggests that biogenicity cannot be taken for granted for all titanite-based textures in metamorphosed basalt glass, but a cautious and critical evaluation of evidence suggests that biogenicity remains the most likely interpretation for previously described titanite microtextures in Paleoarchean pillow lavas.

  6. A cryptoendolithic community in volcanic glass.

    Science.gov (United States)

    Herrera, Aude; Cockell, Charles S; Self, Stephen; Blaxter, Mark; Reitner, Joachim; Thorsteinsson, Thorsteinn; Arp, Gernot; Dröse, Wolfgang; Tindle, Andrew G

    2009-05-01

    Fluorescent in situ hybridization (FISH) and 16S rDNA analysis were used to characterize the endolithic colonization of silica-rich rhyolitic glass (obsidian) in a barren terrestrial volcanic environment in Iceland. The rocks were inhabited by a diverse eubacterial assemblage. In the interior of the rock, we identified cyanobacterial and algal 16S (plastid) sequences and visualized phototrophs by FISH, which demonstrates that molecular methods can be used to characterize phototrophs at the limits of photosynthetically active radiation (PAR). Temperatures on the surface of the dark rocks can exceed 40 degrees C but are below freezing for much of the winter. The rocks effectively shield the organisms within from ultraviolet radiation. Although PAR sufficient for photosynthesis cannot penetrate more than approximately 250 mum into the solid rock, the phototrophs inhabit cavities; and we hypothesize that by weathering the rock they may contribute to the formation of cavities in a feedback process, which allows them to acquire sufficient PAR at greater depths. These observations show how pioneer phototrophs can colonize the interior of volcanic glasses and rocks, despite the opaque nature of these materials. The data show that protected microhabitats in volcanic rocky environments would have been available for phototrophs on early Earth.

  7. Approximate chemical analysis of volcanic glasses using Raman spectroscopy

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    Morgavi, Daniele; Hess, Kai‐Uwe; Neuville, Daniel R.; Borovkov, Nikita; Perugini, Diego; Dingwell, Donald B.

    2015-01-01

    The effect of chemical composition on the Raman spectra of a series of natural calcalkaline silicate glasses has been quantified by performing electron microprobe analyses and obtaining Raman spectra on glassy filaments (~450 µm) derived from a magma mingling experiment. The results provide a robust compositionally‐dependent database for the Raman spectra of natural silicate glasses along the calcalkaline series. An empirical model based on both the acquired Raman spectra and an ideal mixing equation between calcalkaline basaltic and rhyolitic end‐members is constructed enabling the estimation of the chemical composition and degree of polymerization of silicate glasses using Raman spectra. The model is relatively insensitive to acquisition conditions and has been validated using the MPI‐DING geochemical standard glasses1 as well as further samples. The methods and model developed here offer several advantages compared with other analytical and spectroscopic methods such as infrared spectroscopy, X‐ray fluorescence spectroscopy, electron and ion microprobe analyses, inasmuch as Raman spectroscopy can be performed with a high spatial resolution (1 µm2) without the need for any sample preparation as a nondestructive technique. This study represents an advance in efforts to provide the first database of Raman spectra for natural silicate glasses and yields a new approach for the treatment of Raman spectra, which allows us to extract approximate information about the chemical composition of natural silicate glasses using Raman spectroscopy. We anticipate its application in handheld in situ terrestrial field studies of silicate glasses under extreme conditions (e.g. extraterrestrial and submarine environments). © 2015 The Authors Journal of Raman Spectroscopy Published by John Wiley & Sons Ltd PMID:27656038

  8. Glass shards, pumice fragments and volcanic aerosol particles - diagenesis a recorder of volcanic activity?

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    Obenholzner, J. H.; Schroettner, H.; Poelt, P.; Delgado, H.

    2003-04-01

    Detailed SEM/EDS studies of Triassic (Southern Alps, A, I, Sl) and Miocene (Mixteca Alta, Mexico) tuffs revealed that volcanic glass shards can be replaced by zeolites (analcite), chlorites and smectites preserving the shape of primary shards (1). The Triassic pyroclastic deposits have been incorporated in the pre-Alpine burial diagenesis, the Miocene pyroclastic deposits are bentonites. The volcanologist is impressed by the circumstances that million years old pyroclast relict textures can be sized. Shape parameters obtained by image analysis can be compared with much younger pyroclastic deposits (2). Both deposits have not been effected by shearing. The alteration of pumice fragments of Triassic age is not a simple replacement process. Intergrowth of different illites and chlorites and probably vesicle filling by SiO2 and subsequent overgrowth make a reconstruction sometimes difficult. These processes are accompanied by the formation of REE-, Y- and Zr-bearing minerals as well as with the alteration of zircons. Studies of recently erupted ash from Popocatepetl volcano reveal the presence of a variety of µm-sized contact-metamorphosed clasts being a part of the volcanic ash (3). Such clasts should be present in many older pyroclastic deposits, especially where volcanoes had been situated on massive sedimentary units providing contact metamorphism in the realm of a magma chamber or during magma ascent. Volcanic aerosol particles collected in 1997 from the passively degassing plume of Popocatepetl volcano revealed in FESEM/EDS analysis (H. Schroettner and P. Poelt) a wide spectrum of fluffy, spherical and coagulated spherical particles (µm-sized). Under pre-vacuum conditions they remained stable for ca. 3 years (3). In nature the fate of these particles in the atmosphere is unknown. Are there relicts in marine, lacustrine sediments and ice cores, which could be used as proxies of volcanic activity? (1) Obenholzner &Heiken,1999. Ann.Naturhist.Mus.Wien, 100 A, 13

  9. Volcanic glass signatures in spectroscopic survey of newly proposed lunar pyroclastic deposits

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    Besse, S.; Sunshine, J.M.; Gaddis, L.R.

    2014-01-01

    Moon Mineralogy Mapper spectroscopic observations are used to assess the mineralogy of five sites that have recently been proposed to include lunar dark mantle deposits (DMDs). Volcanic glasses have, for the first time, clearly been identified at the location of three of the proposed pyroclastic deposits. This is the first time that volcanic glasses have been identified at such a small scale on the lunar surface from remote sensing observations. Deposits at Birt E, Schluter, and Walther A appear to be glassy DMDs. Deposits at Birt E and Schluter show (1) morphological evidence suggesting a likely vent and (2) mineralogical evidence indicative of the presence of volcanic glasses. The Walther A deposits, although they show no morphological evidence of vents, have the spectroscopic characteristics diagnostic of volcanic glasses. The deposits of the Freundlich-Sharonov basin are separated in two areas: (1) the Buys-Ballot deposits lack mineralogical and morphological evidence and thus are found to be associated with mare volcanism not with DMDs and (2) the Anderson crater deposits, which do not exhibit glassy DMD signatures, but they appear to be associated with possible vent structures and so may be classifiable as DMDs. Finally, dark deposits near the crater Kopff are found to be associated with likely mare volcanism and not associated with DMDs. The spectral identification of volcanic glass seen in many of the potential DMDs is a strong indicator of their pyroclastic origin.

  10. Effects of rolling on wind-induced detachment thresholds of volcanic glass on Mars

    NARCIS (Netherlands)

    S.J. de Vet; J.P. Merrison; M.C. Mittelmeijer-Hazeleger; E.E. van Loon; L.H. Cammeraat

    2014-01-01

    Dunes in the northern lowlands on planet Mars are composed of volcanic sands with high contents of volcanic glass and these deposits are mobilised and transported by winds in the present-day surface environment. In this experimental study we measured fluid thresholds for detachment of Mars-analogue

  11. Massive Volcanic Glass: Natural Pozzolan in the West of São Paulo State

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    Tarcísio José Montanheiro

    2011-04-01

    Full Text Available Some occurrences of massive volcanic glass have been recorded in the western region of São Paulo State duringgeological mapping and prospecting and technological characterization of pozzolanic materials. The massive volcanic glassis associated with trachydacites from the Serra Geral Formation. The geometry of these layers has not been determined yetbecause they are covered by sediments. These rocks were identified as natural pozzolans because their active component,volcanic glass, reacted with lime forming a calcium silicate. The technological properties of the cement produced using suchpozzolans were improved. Furthermore, the use of pozzolans reduces carbon dioxide emission and limestone extractionsince pozzolans replace part of the portland clinker in the final product. This paper presents results of some studies onmassive volcanic glass as an active component of pozzolans. In addition to that, this paper discusses the importance of thisfinding for construction industry and the great potential of pozzolanic materials, due to the considerable size of Serra GeralFormation in Brazil.

  12. Control of Montmorillonite Surface Coatings on Quartz Grains in Bentonite by Precursor Volcanic Glass

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    Wendlandt, R. F.; Harrison, W. J.

    2008-12-01

    The pathogenic tendencies of respirable-sized quartz grains may be dependent on inherent characteristics of the quartz as well as external factors. Surface coatings on quartz are of particular interest as they modify both physical and chemical properties of quartz grain surfaces and sequester the grain from contact with reactive lung fluids. Wendlandt et al. (Appl. Geochem. 22, 2007) investigated the surface properties of respirable-sized quartz grains in bentonites and recognized pervasive montmorillonite surface coatings on the quartz that resisted removal by repeated vigorous washings and reaction with HCl. To understand the persistence of montmorillonite coatings on quartz grains of igneous origin, volcanic ash deposits of varying age and degree of alteration to montmorillonite were sampled in Utah, including the distal Lava Creek (c. 0.64 Ma) and Bishop Tuffs (c. 0.74 Ma), and SW Colorado (Conejos Fm, San Juan Volcanic Field) for comparison with commercial grade Cretaceous-age "western" and "southern" bentonites. Quartz grains, hand-picked from these samples, were analyzed using FE-SEM and HRTEM. Continuous coatings of volcanic glass occur on quartz grains from the distal volcanic ash samples. As glass alteration to montmorillonite becomes more extensive, quartz grain surfaces start to display patches of montmorillonite. These patches become continuous in extent on quartz grains from the bentonites. Late precipitation of opal- CT lepispheres is consistent with the alteration reaction for volcanic glass: Volcanic glass + H2O = montmorillonite + SiO2(am) + ions(aq). HRTEM of quartz grains reveals an amorphous surface layer, consistent with a volcanic glass coating. Our results indicate that persistent montmorillonite coatings on quartz grains in bentonites are related to precursor volcanic glass coatings on these grains. The absence of glass coatings on other mineral grains in bentonite (feldspar, biotite) may be a consequence of the presence of strong cleavage

  13. Biologically mediated dissolution of volcanic glass in seawater

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    Staudigel, H; Yayanos, A; Chastain, R; Davies, G.T.; Verdurmen, E.A Th; Schiffmann, P; Bourcier, R; de Baar, H.J.W.

    1998-01-01

    We studied the effects of biological mediation on the dissolution of basaltic glass in seawater. Experiments with typical seawater microbial populations were contrasted with a sterile control, and reactions were monitored chemically and isotopically. Biologically mediated experiments produce twice

  14. Long-term stability of hydrogen isotope ratios in hydrated volcanic glass

    Science.gov (United States)

    Cassel, Elizabeth J.; Breecker, Daniel O.

    2017-03-01

    The advancement of conceptual and numerical geodynamic models necessitates quantitative, orogen-scale paleoelevation data. Felsic volcanic glasses, which record the hydrogen isotope compositions (δD) of meteoric water shortly after deposition, provide several advantages as a paleoelevation proxy. Questions remain, however, about the reliability of this relatively new proxy, including the effect of hydrofluoric (HF) acid abrasion in the preparation of glass shards for hydrogen isotope analysis and the stability of hydrogen isotope ratios in hydrated glass shards over geologic time (106-107 years). HF acid abrasion of natural ancient glass shards results in systematic shifts in glass δD values away from modern water δD values. To evaluate the effectiveness of HF acid abrasion, we treated 70-150 μm glass shards separated from various natural tephras with deuterium-labeled water (DLW; δD = +18,205‰) for up to 400 days. For all glasses, this treatment resulted in elevated δD values in comparison to untreated samples. HF acid abrasion after DLW exposure, however, removed this effect and restored glass shards to their original untreated δD values in samples older than 104 years. HF acid abrasion removes hydrous alteration precipitates at the glass surface without measurably changing the δD values of the underlying hydrated glass, regardless of abrasion duration or glass composition. Additionally, 45-34 Ma glasses record δD values that directly reflect their depositional environments as determined by stratigraphy: glasses from tuffs deposited in demonstrably evaporative lacustrine environments have relatively high δD values compared to glasses from contemporaneous tuffs deposited in nearby fluvial environments, which have much lower δD values. The preservation of δD values that systematically vary with original depositional environment, despite >30 Myr of post-hydration exposure to the same meteoric water, indicates that these volcanic glasses resisted

  15. Comparative analyses of glass fragments from brittle fracture experiments and volcanic ash particles

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    Dürig, Tobias; Mele, Daniela; Dellino, Pierfrancesco; Zimanowski, Bernd

    2012-04-01

    Explosive volcanic eruptions are characterized by the rapid fragmentation of a magmatic melt into ash particles. In order to describe the energy dissipation during fragmentation it is important to understand the mechanism of material failure. A quantitative description of fragmentation is only possible under controlled laboratory conditions. Industrial silicate glasses have a high structural affinity with magmatic melts and have the advantage of being transparent, which allows the study of the evolution of fractures by optical methods on a time scale relevant for explosive volcanism. With this aim, a series of low speed edge-on hammer impact experiments on silicate glass targets has been conducted, leading to the generation of fragments in the grain-size spectra of volcanic ash. In order to verify the general transferability of the experimentally generated fragmentation dynamics to volcanic processes, the resulting products were compared, by means of statistical particle-shape analyses, to particles produced by standardized magma fragmentation experiments and to natural ash particles coming from deposits of basaltic and rhyolitic compositions from the 2004 Grimsvötn and the Quaternary Tepexitl tuff-ring eruptions, respectively. Natural ash particles from both Grimsvötn and Tepexitl show significant similarities with experimental fragments of thermally pre-stressed float glasses, indicating a dominant influence of preexisting stresses on particle shape and suggesting analogous fragmentation processes within the studied materials.

  16. Sintering of Glass in Hydrous Atmospheres and its Implications for Welding of Volcanic Deposits

    Science.gov (United States)

    von Aulock, F. W.; Wadsworth, F. B.; Lavallée, Y.; Vasseur, J.

    2014-12-01

    Volcanic ash sintering can occur during hot deposition or upon reheating, and recently published models have improved our understanding of viscous sintering timescales at magmatic temperatures. However, in most volcanic environments, water is present either from meteoric or magmatic sources. Water significantly lowers the viscosity of liquids and therefore should alter the onset temperature and timescales of sintering. The diffusion of water in melts and glasses at low (sub-liquidus) temperatures and pressures, and the partitioning between water vapor and dissolved water species are poorly understood. We investigate the impact of a water rich Ar -atmosphere on viscous sintering at temperatures close to the glass transition. Synthetic near-spherical soda-lime silica glass beads with a well-constrained size of about 10-350μm (produced by Spheriglass) were heated in simultaneous thermal analyses of both differential scanning calorimetry and thermogravimetry. Glass transition temperature onset and mass stayed consistent under argon atmosphere during successive heating cycles at a rate of 10 °C.min-1. Contrastingly, preliminary results show that, when heated, closely packed in a water-argon atmosphere (1) there is a measurable water uptake during timescales as short as 2 hours, and (2) sintering is more efficient and densification takes place at lower temperatures and/or within shorter timescales. Sintering of volcanic materials reduces both porosity and permeability of volcanic products. The process of sintering is, however, limited by quenching of the material shortly after eruption. External water present during deposition could allow welding of pyroclastic deposits at conditions and timescales otherwise not achievable from the deposited pyroclasts alone.. Viscous sintering in a water-rich atmosphere may enhance resorption and encourage the formation of vesicle-free obsidian.

  17. U-series dating of pillow rim glass from recent volcanism at an Axial Volcanic Ridge

    Science.gov (United States)

    Thomas, L. E.; van Calsteren, P. W.; Jc024 Shipboard Party

    2010-12-01

    Visual observations using camera systems on the tethered ROV Isis deployed during the 2008 JC024 cruise to the Mid Atlantic Ridge at 45°N showed1 numerous monogenetic volcanoes that are essentially piles of lava pillows. The pillows are usually ˜1m diameter and >2m long and form mounds with average dimensions around 300m diameter, ˜150m altitude, and 0.005km3 volume. Small protrusions, 10-50cm long, which are numerous on pillows appear to be the youngest regions, were sampled using the pincers on the hydraulic arms of Isis, and returned to the surface. On the surface, any glass crust on the pillow protrusions was chiselled off using clean tools and double bagged in polythene. In the laboratory a portion of the glass was crushed in a jeweller’s roller mill and sieved using stainless steel sieves to obtain a sufficient amount of the fraction 0.125-0.250mm for hand picking, using a binocular microscope with the glass submerged in a mix of water and iso-propyl alcohol. The samples were subsequently leached using the procedure of Standish & Sims2. Samples were spiked with a mixed 229Th-236U spike and the U, Th and Ra fractions were separated and purified using standard chemistry methods. U and Th isotope ratios were determined using a Nu Instruments MC-ICPMS and Ra isotope ratios were determined using a MAT-262-RPQII TIMS instrument. The U-series data were evaluated using a MathCad program based on published4,5,6 equations. The data can be successfully modelled by assuming the ‘accepted’ mantle upwelling rate for the region of 11mm.y-1. The U-Th characteristics are mostly derived during ‘porous flow’ magma upwelling in the garnet stability zone, ranging to a depth of 60km with incipient melting starting at 70km. Above 60km depth the melt fraction will be >3% and the mantle mineralogy devoid of phases that fractionate U-Th significantly. Moreover, at melt fractions >3%, channel flow will be dominant and magma will transit to eruption on time-scales that are

  18. 3.5 billion years of glass bioalteration: Volcanic rocks as a basis for microbial life?

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    Staudigel, Hubert; Furnes, Harald; McLoughlin, Nicola; Banerjee, Neil R.; Connell, Laurie B.; Templeton, Alexis

    2008-08-01

    Alteration textures in volcanic glass from the seafloor fall into two classes, one suggestive of abiotic/diffusive hydration and chemical exchange, and another likely to be caused by microbial, cavity-forming, congruent dissolution. Glass bioalteration is common in submarine lavas throughout the world's ocean, dominant in the upper 300 m of the oceanic crust, and found in all well-preserved ophiolites and greenstone belts dating back to 3.5 Ga. It may yield a significant fraction of the global biomass and geochemical fluxes and is relevant to the development of the earliest life on Earth. We present a critical review concerning these glass bioalteration textures and present new data on their microchemical environment. We explore arguments for their biogenicity and further develop the prevalent model for their formation by relating corrosion morphology to the mechanism of microbial dissolution. Biological alteration produces conspicuous micron-scale granular and tubular textures. Granular glass alteration is well explained by colonizing microbes that selectively dissolve the glass in their contact area, forming a sponge-like interconnected network of micron-sized cavities along glass surfaces. Tubular alteration meanwhile, is more likely to be caused by filamentous cell extensions in a process similar to fungal tunneling of soil feldspars and marine carbonates. While we see clear functional similarities to fungal dissolution behavior, we do not know whether fungal or prokaryotic organisms are involved. However, this functional constraint may eventually help to identify potential microbes responsible for these features, potentially including eukaryotic or prokaryotic organisms. Yet, we caution that these organisms may be difficult to identify and to study, because they are likely to be sparsely distributed, slow growing, and difficult to cultivate.

  19. Adhesion Between Volcanic Glass and Spacecraft Materials in an Airless Body Environment

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    Berkebile, Stephen; Street, Kenneth W., Jr.; Gaier, James R.

    2012-01-01

    The successful exploration of airless bodies, such as the Earth s moon, many smaller moons of the outer planets (including those of Mars) and asteroids, will depend on the development and implementation of effective dust mitigation strategies. The ultrahigh vacuum environment (UHV) on the surfaces of these bodies, coupled with constant ion and photon bombardment from the Sun and micrometeorite impacts (space weathering), makes dust adhesion to critical spacecraft systems a severe problem. As a result, the performance of thermal control surfaces, photovoltaics and mechanical systems can be seriously degraded even to the point of failure. The severe dust adhesion experienced in these environments is thought to be primarily due to two physical mechanisms, electrostatic attraction and high surface energies, but the dominant of these has yet to be determined. The experiments presented here aim to address which of these two mechanisms is dominant by quantifying the adhesion between common spacecraft materials (polycarbonate, FEP and PTFE Teflon, (DuPont) Ti-6-4) and a synthetic noritic volcanic glass, as a function of surface cleanliness and triboelectric charge transfer in a UHV environment. Adhesion force has been measured between pins of spacecraft materials and a plate of synthetic volcanic glass by determining the pull-off force with a torsion balance. Although no significant adhesion is observed directly as a result of high surface energies, the adhesion due to induced electrostatic charge is observed to increase with spacecraft material cleanliness, in some cases by over a factor of 10, although the increase is dependent on the particular material pair. The knowledge gained by these studies is envisioned to aid the development of new dust mitigation strategies and improve existing strategies by helping to identify and characterize mechanisms of glass to spacecraft adhesion for norite volcanic glass particles. Furthermore, the experience of the Apollo missions

  20. Quantitative micro-Raman analysis of volcanic glasses: influence and correction of matrix effects

    Science.gov (United States)

    Di Muro, Andrea

    2014-05-01

    . Geochimica et Cosmochimica Acta, 74, 5641-5656. Mercier, M., Di Muro, A., Giordano, D., Métrich, N.,Pichavant, M., Clocchiatti, R., Montagnac, G. (2009) The influence of glass polymerization and oxidation on micro-Raman water analysis in alumino-silicate glasses. Geochimica et Cosmochimica Acta, 73, 197-217 Di Muro, A., Métrich, N., Mercier, M., Giordano, D., Massare, D., Montagnac, G. (2009) Micro-Raman determination of iron redox state in dry natural glasses : application to peralkaline rhyolites and basalts. Chemical Geology (Special volume on experimental techniques for the study of hydrothermal fluids and silicate melts) 259:78-88. Di Muro A, Villemant B, Montagnac G, Scaillet B, Reynard B (2006) The influence of glass composition on the determination of water content and speciation by Raman spectrometry. Geochimica and Cosmochimica Acta, 70, 2868-2884 Di Muro A, Giordano D., Villemant B, Montagnac G, Romano C. (2006) Influence of composition and thermal history of volcanic glasses on water content determination by microRaman spectrometry. Applied Geochemistry (Special volume on developments in analytical geochemistry). 21, 802-812. Application Di Muro, A., Staudacher, T., Ferrazzini, V., Villemant, B., Besson, P., Garofalo, C. (2014) Tracking magma injection in the Piton de la Fournaise volcanic edifice after the 2007 Summit Caldera Collapse by Pele's Hair Composition. Chapman Special Volume on Hawaiian volcanoes, AGU Books. Ardia, P., Di Muro, A., Giordano, D., Massare, D., Sanchez-Valle, C., Schmidt, M.W. (2014) Densification mechanisms of haplogranite glasses as a function of water content and pressure based on density and Raman data. Under review, submitted to Geochimica et Cosmochimica Acta. Métrich, N, Allard, P., Aiuppa, A., Bani, P., Bertagnini, A., Belhadj, O., Di Muro, A., Garaebiti, E., Massare, D., Parello, F., Shinohara, H. (2011) Magma and volatile feeding of post-caldera Yasur volcanism and block resurgence in Tanna island (Vanuatu arc). Journal of

  1. Growth and preservation of subsurface bio-signatures in submarine volcanic glass

    Science.gov (United States)

    Banerjee, N.; Muehlenbachs, K.; Furnes, H.

    2003-04-01

    We suggest that an unlikely substrate, altered submarine basalt, may preserve early biomarkers. Basalts are likely to be returned by any extra-terrestrial sample return mission and should be assessed for their potential in recording and preserving biological traces. Bioalteration of MORB glass in sub-seasurface pillow rims and tuffs has been documented. Petrographic evience of fossil microbial alteration is seen in two textures: tubular and granular. Tubular textures are characterized by micron-scale, tubular to vermicular, channel-like features and branching bodies extending into fresh glass. Granular textures appear as solid bands, semicircles or irregular patches of individual and/or coalesced spherical bodies with irregular protrusions into fresh glass. These textures are observed to extend away from fractures and grain boundaries, where liquid water was once present, into fresh glass. Detailed SEM imaging of these features in thin sections and on grain mounts of freshly exposed surfaces have revealed complex channels, delicate filament-like structures, and material resembling desiccated biofilm. The channels are highly convoluted and are occasionally filled with clay minerals, probably smectite. X-ray element maps show elevated levels of C, N, P, and K associated with the microbial alteration features. Micron sized grains of iron sulphides have also been identified at the margin of some of these features, possibly resulting from reduction of seawater sulphate by microbes. Carbon isotope ratios of disseminated carbonate in microbially altered volcanic glass are variably depleted by as much as -20 per mil, suggesting biologic fractionation. We have also treated samples with nucleic acid stains that specifically bind to DNA and RNA revealing DNA/RNA associated with areas of suspected microbial alteration. However, the evolutionary history of glass bioalteration or its preservability in the geological record is not known. We searched for evidence of ancient

  2. Hydrogen isotopes in lunar volcanic glasses and melt inclusions reveal a carbonaceous chondrite heritage.

    Science.gov (United States)

    Saal, Alberto E; Hauri, Erik H; Van Orman, James A; Rutherford, Malcolm J

    2013-06-14

    Water is perhaps the most important molecule in the solar system, and determining its origin and distribution in planetary interiors has important implications for understanding the evolution of planetary bodies. Here we report in situ measurements of the isotopic composition of hydrogen dissolved in primitive volcanic glass and olivine-hosted melt inclusions recovered from the Moon by the Apollo 15 and 17 missions. After consideration of cosmic-ray spallation and degassing processes, our results demonstrate that lunar magmatic water has an isotopic composition that is indistinguishable from that of the bulk water in carbonaceous chondrites and similar to that of terrestrial water, implying a common origin for the water contained in the interiors of Earth and the Moon.

  3. Preliminary Hydrogen Isotope Data from Volcanic Glass in the Peruvian Andes

    Science.gov (United States)

    White, E.; Cassel, E. J.

    2016-12-01

    The Central Andes contain the highest ocean-continent subduction-driven plateau in the world, and are a model for the complex interactions between climate and topography. Existing tectonic models for Andean orogenesis vary widely in both the timing and driving mechanisms of surface uplift. Proposed mechanisms include early Cenozoic uplift in the west during contractional deformation, gradual late Cenozoic surface uplift resulting from continuous crustal thickening and shortening, and rapid late Cenozoic surface uplift from delamination of the South American lithosphere. To constrain the orogenic and climate history of southern Peru, we are using hydrogen isotope data from volcanic glasses sampled from Eocene-Pleistocene vitric ignimbrites deposited from the Pacific coast across the Western Cordillera magmatic arc and northern Altiplano. Ignimbrites are partially welded to unwelded, range in thickness from 10-65m, and are composed of 5-35% phenocrysts of biotite, quartz, and feldspar, with up to 40% lithic and pumice clasts. Many ignimbrites consist of multiple flow units and interbedded fluvial sediments and are commonly underlain or capped by andesitic, basaltic, and dacitic flows. Initial hydrogen isotope values from ancient meteoric water preserved in volcanic glasses (δDglass) from 40-2 Ma show decreasing δD values for samples located in the high Western Cordillera, while samples closer to the Pacific coast show little variation in δD over the past 40 Ma. Further sampling over a greater geographic range, coupled with new high precision geochronology and modeling of the influence of topography and climate on isotope distillation rates, is needed to determine the most likely drivers for changes in δD values and to quantify the magnitude of those changes. δDglass values will be compared with multiple topographic scenarios using a three-dimensional isotope-tracking global climate model, calibrated with modern hydrogen isotope values from soil, precipitation

  4. Intumescence and pore structure of alkali-activated volcanic glasses upon exposure to high temperatures

    Science.gov (United States)

    Erdogan, S. T.

    2015-12-01

    Structures formed with ground perlite, a natural volcanic glass, activated with NaOH solutions, are shown to possess the ability to expand up to ~225 % of their original volumes upon exposure to temperatures in the 200-600 °C range. Porous solid with 3-7 MPa compressive strength and ˜450 kg/m3 or higher density are obtained. The observed expansion is believed to occur due to a loss of silanol condensation water, as vapor and is accompanied by an up to ~20 % loss in mass. A drop in pH to near-neutral values supports this idea. The size and total amount of pores in the final solid are controlled by concentration of the NaOH solution and thermal processing conditions. The pores formed are observed to be ~1-10 μm to mm-sized. The ability of perlite-based solids to intumesce over specific temperature ranges could be beneficial in applications where absorption of thermal energy is necessary, such as passive fire protection.

  5. Statistical extraction of volcanic sulphate from non-Polar ice cores

    NARCIS (Netherlands)

    Moore, J.C.; Beaudon, E.; Kang, S.; Divine, D.; Isaksson, E.; Pohjola, V.A.; van de Wal, R.S.W.

    2012-01-01

    Ice cores from outside the Greenland and Antarctic ice sheets are difficult to date because of seasonal melting and multiple sources (terrestrial, marine, biogenic and anthropogenic) of sulfates deposited onto the ice. Here we present a method of volcanic sulfate extraction that relies on fitting

  6. Statistical extraction of volcanic sulphate from non-Polar ice cores

    NARCIS (Netherlands)

    Moore, J.C.; Beaudon, E.; Kang, S.; Divine, D.; Isaksson, E.; Pohjola, V.A.; van de Wal, R.S.W.

    2012-01-01

    Ice cores from outside the Greenland and Antarctic ice sheets are difficult to date because of seasonal melting and multiple sources (terrestrial, marine, biogenic and anthropogenic) of sulfates deposited onto the ice. Here we present a method of volcanic sulfate extraction that relies on fitting su

  7. Late Paleogene topography of the Central Rocky Mountains and western Great Plains region using hydrogen isotope ratios in volcanic glass

    Science.gov (United States)

    Rossetto, G.; Fricke, H. C.; Cassel, E. J.; Evanoff, E.

    2015-12-01

    The Central Rocky Mountains (CRM), located in southern Wyoming, Colorado, and northern New Mexico, are characterized by the highest elevation basins (up to 2500 m) and mountains (over 4000 m) in the North American Cordillera. The timing and drivers for surface uplift of the CRM have not been conclusively determined. The goal of this study is to constrain the timing of surface uplift of the CRM by comparing hydrogen isotope ratios of hydration waters (δDglass) in late Paleogene volcanic glasses preserved in felsic tuffs deposited in CRM basins to δDglass values from glasses of similar age (34.9 to 32.2 Ma) preserved in tuffs from the surrounding Great Plains. The tuffs deposited in the Great Plains, to the north and east of the CRM, are currently at elevations of 1100-1600 m. Volcanic glass hydrates shortly after deposition, preserving the δD of ancient meteoric water on geologic timescales, and can thus be used as a proxy for ancient precipitation δD values. Volcanic glasses from the CRM have δDglass values that are an average of ~31‰ higher than δDglass values from the Great Plains, while modern day precipitation δD values in the CRM are ~25‰ lower than δD values in the Great Plains. These results suggest that the uplift of the CRM relative to the surrounding Great Plains occurred after ~32 Ma. This requires a mechanism such as mantle upwelling or differential crustal hydration, not solely Laramide tectonism, to uplift the CRM to current elevations. Elevation, however, may not have been the only control on the spatial distribution of precipitation δD values across the western US. Similar to the modern, mixing of Pacific and Gulf coast air masses likely occurred during the latest Paleogene, driving regional variability in δD values of precipitation.

  8. Selective Extraction Methods for Aluminium, Iron and Organic Carbon from Montane Volcanic Ash Soils

    Institute of Scientific and Technical Information of China (English)

    B. JANSEN; F. H. TONNEIJCK; J. M. VERSTRATEN

    2011-01-01

    Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle.Given the central role of A1 and Fe in stabilizing organic matter in volcanic ash soils,we assessed various extraction methods of A1,Fe,and C fractions from montane volcanic ash soils in northern Ecuador,aiming at elucidating the role of A1 and Fe in stabilizing soil organic matter (SOM).We found extractions with cold sodium hydroxide,ammonium oxalate/oxalic acid,sodium pyrophosphate,and sodium tetraborate to be particularly useful.Combination of these methods yielded information about the role of the mineral phase in stabilizing organic matter and the differences in type and degree of complexation of organic matter with Al and Fe in the various horizons and soil profiles.Sodium tetraborate extraction proved the only soft extraction method that yielded simultaneous information about the Al,Fe,and C fractions extracted.It also appeared to differentiate between SOM fractions of different stability.The fractions of copper chloride- and potassium chloride-extractable A1 were useful in assessing the total reactive and toxic Al fractions,respectively.The classical subdivision of organic matter into humic acids,fulvic acids,and humin added little useful information.The use of fulvic acids as a proxy for mobile organic matter as done in several model-based approaches seems invalid in the soils studied.

  9. Complex Indigenous Organic Matter Embedded in Apollo 17 Volcanic Black Glass Surface Deposits

    Science.gov (United States)

    Thomas-Keprta, Kathie L.; Clemett, S. J.; Ross, D. K.; Le, L.; Rahman, Z.; Gonzalez, C.; McKay, D. S.; Gibson, E. K.

    2013-01-01

    Papers presented at the first Lunar Science Conference [1] and those published in the subsequent Science Moon Issue [2] reported the C content of Apollo II soils, breccias, and igneous rocks as rang-ing from approx.50 to 250 parts per million (ppm). Later Fegley & Swindle [3] summarized the C content of bulk soils from all the Apollo missions as ranging from 2.5 (Apollo 15) to 280 ppm (Apollo 16) with an overall average of 124+/- 45 ppm. These values are unexpectedly low given that multiple processes should have contributed (and in some cases continue to contribute) to the lunar C inventory. These include exogenous accretion of cometary and asteroidal dust, solar wind implantation, and synthesis of C-bearing species during early lunar volcanism. We estimate the contribution of C from exogenous sources alone is approx.500 ppm, which is approx.4x greater than the reported average. While the assessm ent of indigenous organic matter (OM) in returned lunar samples was one of the primary scientific goals of the Apollo program, extensive analysis of Apollo samples yielded no evidence of any significant indigenous organic species. Furthermore, with such low concentrations of OM reported, the importance of discriminating indigenous OM from terrestrial contamination (e.g., lunar module exhaust, sample processing and handling) became a formidable task. After more than 40 years, with the exception of CH4 [5-7], the presence of indigenous lunar organics still remains a subject of considerable debate. We report for the first time the identification of arguably indigenous OM present within surface deposits of black glass grains collected on the rim of Shorty crater during the Apollo 17 mission by astronauts Eugene Cernan and Harrison Schmitt.

  10. Apollo 15 yellow-brown volcanic glass: Chemistry and petrogenetic relations to green volcanic glass and olivine-normative mare basalts

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, S.S.; Schmitt, R.A.; (Oregon State Univ., Corvallis (USA)); Delano, J.W. (State Univ. of New York, Albany (USA))

    1988-10-01

    Apollo 15 yellow-brown glass is one of twenty-five, high Mg, primary magmas emplaced on the lunar surface in pyroclastic eruptions. Forty spherules of this glass were individually analyzed by electron microprobe and INAA for major- and trace-elements. The abundances demonstrate that this primary magma was produced by partial melting of differentiated cumulates in the lunar mantle. Models are developed to explain the possible source-regions of several Apollo 15 and Apollo 12 low-Ti mare magmas as being products of hybridization involving three ancient differentiated components of a primordial lunar magma ocean: (a) early olivine {plus minus} orthopyroxene cumulates; (b) late-stage clinopyroxene + pigeonite + ilmenite + plagioclase cumulates; and (c) late-stage inter-cumulus liquid.

  11. Petrography and geochemistry of achnelithic tephra from Las Herrerías Volcano (Calatrava volcanic field, Spain): Formation of nephelinitic achneliths and post-depositional glass alteration

    Science.gov (United States)

    Carracedo-Sánchez, M.; Sarrionandia, F.; Arostegui, J.; Errandonea-Martin, J.; Gil-Ibarguchi, J. I.

    2016-11-01

    We present the results of a petrographic and geochemical study carried out on a layer of achnelithic tephra outcropping at the base of the volcanic cone of Las Herrerías (Miocene-Quaternary volcanic region of Campo de Calatrava, Spain). The tephra, with a composition of nephelinite and ash (volcanic maar lake. Afterwards, there was no more water circulation through the achnelithic tephra, which was sealed from water by overlying hydrovolcanic tuff deposits. It was this isolation that made possible the preservation of glass to the present day.

  12. Alteration textures in terrestrial volcanic glass and the associated bacterial community.

    Science.gov (United States)

    Cockell, C S; Olsson-Francis, K; Herrera, A; Meunier, A

    2009-01-01

    Alteration textures were examined in subglacial (hyaloclastite) deposits at Valafell, Southern Iceland. Pitted and 'elongate' alteration features are observed in the glass similar to granular and tubular features reported previously in deep-ocean basaltic glasses, but elongate features generally did not have a length to width ratio greater than five. Elongate features were found in only 7% of surfaces. Crystalline basalt clasts, which are incorporated into the hyaloclastite, did not display elongate structures. Pitted alteration features were poorly defined in crystalline basalt, comprising only 4% of the surface compared to 47% in the case of basaltic glass. Examination of silica-rich glass (obsidian) and rhyolite similarly showed poorly defined pitted textures that comprised less than 15% of the surface and no elongate features were observed. These data highlight the differences in alteration textures between terrestrial basaltic glass and previously studied deep-ocean and subsurface basaltic glass, and the important role of mineralogy in controlling the type and abundance of alteration features. The hyaloclastite contains a diverse and abundant bacterial population, as determined by 16S rDNA analysis, which could be involved in weathering the glass. Despite the presence of phototrophs, we show that they were not involved in the production of most alteration textures in the basaltic glass materials we examined.

  13. E-MORB glasses from the Gakkel Ridge (Arctic Ocean) at 87°N: evidence for the Earth's most northerly volcanic activity

    OpenAIRE

    R. Mühe; Bohrmann, H.; Garbe-Schönberg, Dieter; Kassens, Heidemarie

    1997-01-01

    During the ARCTIC '91 expedition aboard RV Polarstern (ARK VIII/3) to the Central Arctic Ocean, a box corer sample on the Gakkel Ridge at 87 degrees N and 60 degrees E yielded a layer of sand-sized, dark brown volcanic glass shards at the surface of the sediment core. These shards have been investigated by petrographic, mineralogical, geochemical and radiogenic isotope methods. The nearly vesicle-free and aphyric glass shards bear only minute microphenocrysts of magnesiochromite and olivine (...

  14. Measurements of an ion beam diameter extracted into air through a glass capillary

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Natsuko, E-mail: fujita.natsuko@jaea.go.jp [Graduate School of Humanities and Sciences, Nara Women’s University, Nara, 630 8506 (Japan); Yamaki, Atsuko [Graduate School of Humanities and Sciences, Nara Women’s University, Nara, 630 8506 (Japan); Ishii, Kunikazu; Ogawa, Hidemi [Department of Physics, Nara Women’s University, Nara, 630 8506 (Japan)

    2013-11-15

    To establish techniques for in-air materials analysis using a glass capillary, we studied the beam distribution extracted in air as a function of the distance between the exit of the capillary and the target. We measured three-dimensional intensity distributions of the extracted beams, and compared the observed results with the model calculation. The comparison showed that the glass capillary technique is designed to reduce a divergence of the beam extracted into the air by a beam-focusing effect.

  15. Marine-continental tephra correlations: Volcanic glass geochemistry from the Marsili Basin and the Aeolian Islands, Southern Tyrrhenian Sea, Italy

    Science.gov (United States)

    Albert, P. G.; Tomlinson, E. L.; Smith, V. C.; Di Roberto, A.; Todman, A.; Rosi, M.; Marani, M.; Muller, W.; Menzies, M. A.

    2012-06-01

    Major, minor and trace element analysis of volcanic glass in proximal and distal (Lipari (Monte Pilato; 776 cal AD); (2) Vulcano; and (3) Campi Flegrei (Soccavo 1; 11,915-12,721 cal years BP). Whether a polymictic coarse grained volcaniclastic turbidite in the Marsili Basin originated from collapse on Salina remains unresolved because multi-elemental analysis raises doubt about the published correlation to the Pollara region. It is evident that correlation of proximal continental and distal marine tephras, at a high level of confidence, requires a full complement of major, minor and trace element data. In conjunction with considerations of the mineralogy and morphology of juvenile deposits these data help define petrological lineages such that precise provenance can be established. Whilst a precise proximal-distal match must be based on identical major, minor and trace element concentrations it is clear that resurgent activity from a single volcano can produce magmas with identical compositions. In such cases stratigraphic relationships must complement any geochemical study. Occasionally proximal stratigraphies may be unrepresentative of the complete eruptive history because of a lack of exposure due to burial by more recent effusive and explosive activity, or sector collapse which can remove vital stratigraphy particularly on volcanic islands.

  16. Indigenous Carbonaceous Phases Embedded Within Surface Deposits on Apollo 17 Volcanic Glass Beads

    Science.gov (United States)

    Thomas-Keprta, K. L.; Clemett, S. J.; Ross, D. K.; Le, L.; McKay, D. S.; Gibson, E. K.; Gonzalez, C.

    2012-01-01

    The assessment of indigenous organic matter in returned lunar samples was one of the primary scientific goals of the Apollo program. Prior studies of Apollo samples have shown the total amount of organic matter to be in the range of approx 50 to 250 ppm. Low concentrations of lunar organics may be a consequence not only of its paucity but also its heterogeneous distribution. Several processes should have contributed to the lunar organic inventory including exogenous carbonaceous accretion from meteoroids and interplanetary dust particles, and endogenous synthesis driven by early planetary volcanism and cosmic and solar radiation.

  17. FE-SEM, FIB and TEM Study of Surface Deposits of Apollo 15 Green Glass Volcanic Spherules

    Science.gov (United States)

    Ross, Daniel K.; Thomas-Keprta, K. L.; Rahman, Z.; Wentworth, S. J.; McKay, D. S.

    2011-01-01

    Surface deposits on lunar pyroclastic green (Apollo 15) and orange (Apollo 17) glass spherules have been attributed to condensation from the gas clouds that accompanied fire-fountain eruptions. The fire fountains cast molten lava high above the lunar surface and the silicate melt droplets quenched before landing producing the glass beads. Early investigations showed that these deposits are rich in sulfur and zinc. The deposits are extremely fine-grained and thin, so that it was never possible to determine their chemical compositions cleanly by SEM/EDX or electron probe x-ray analysis because most of the excited volume was in the under-lying silicate glass. We are investigating the surface deposits by TEM, using focused ion beam (FIB) microscopy to extract and thin the surface deposits. Here we report on chemical mapping of a FIB section of surface deposits of an Apollo green glass bead 15401using the ultra-high resolution JEOL 2500 STEM located at NASA Johnson Space Center.

  18. Assimilation in lunar basalts and volcanic glasses: Implications for a heterogenous mantle source region

    Science.gov (United States)

    Finnila, A. B.; Hess, P. C.; Rutherford, M. J.

    1993-01-01

    Several scientists have called on assimilation of anorthositic crustal material or KREEP compositions to explain various lunar lithologies. In order to address the practicality of such processes, some techniques for calculating how much assimilation is possible in magma chambers and dikes based on thermal energy balances and simple fluid mechanical constraints are outlined. In a previous effort, it was demonstrated that dissolution of plagioclase in an iron-free basalt was too slow to contaminate magmas, and that the energy cost of melting plagioclase-rich crustal material was prohibitive both in magma chambers and in dike conduits. This analysis was extended to include dissolution rates in an orange glass composition and to quantitatively predict the maximum contamination possible due to assimilation of both lunar crustal material and KREEP.

  19. Self-sustained vibrations in volcanic areas extracted by Independent Component Analysis: a review and new results

    Science.gov (United States)

    de Lauro, E.; de Martino, S.; Falanga, M.; Palo, M.

    2011-12-01

    We investigate the physical processes associated with volcanic tremor and explosions. A volcano is a complex system where a fluid source interacts with the solid edifice so generating seismic waves in a regime of low turbulence. Although the complex behavior escapes a simple universal description, the phases of activity generate stable (self-sustained) oscillations that can be described as a non-linear dynamical system of low dimensionality. So, the system requires to be investigated with non-linear methods able to individuate, decompose, and extract the main characteristics of the phenomenon. Independent Component Analysis (ICA), an entropy-based technique is a good candidate for this purpose. Here, we review the results of ICA applied to seismic signals acquired in some volcanic areas. We emphasize analogies and differences among the self-oscillations individuated in three cases: Stromboli (Italy), Erebus (Antarctica) and Volcán de Colima (Mexico). The waveforms of the extracted independent components are specific for each volcano, whereas the similarity can be ascribed to a very general common source mechanism involving the interaction between gas/magma flow and solid structures (the volcanic edifice). Indeed, chocking phenomena or inhomogeneities in the volcanic cavity can play the same role in generating self-oscillations as the languid and the reed do in musical instruments. The understanding of these background oscillations is relevant not only for explaining the volcanic source process and to make a forecast into the future, but sheds light on the physics of complex systems developing low turbulence.

  20. Can alteration experiments on impact melts from El'gygytgyn and volcanic glasses shed new light on the formation of the Martian surface?

    Science.gov (United States)

    Hellevang, Helge; Dypvik, Henning; Kalleson, Elin; Pittarello, Lidia; Koeberl, Christian

    2013-07-01

    This investigation involved three specimens: an altered felsic sample of impactite from the ICDP El'gygytgyn drill core D1c, and two reference volcanics from Iceland, namely a rhyolitic glass and a basaltic glass. The goal of this work was to better understand the alteration of impact melt and volcanic glass, and to apply the results to an investigation of alteration processes below the surface of Mars. Hydrothermal batch alteration experiments with the El'gygytgyn sample showed formation of various silica phases such as cristobalite, opal, and quartz. According to geochemical modeling, zeolites were also expected, but zeolite minerals already present in the impactite prior to the experiment may have masked possible experimental zeolite growth. Basaltic glass was altered to smectite, talc, and opal. The accompanying numerical modeling gave results that were similar or comparable to the laboratory experiments. Rhyolitic glass was kinetically more stable than basaltic glass, and showed only minor formation of calcite and feldspar during the 3-week experiment. The study showed that closed-system isochemical alteration of both siliceous and mafic glasses and melts results in the formation of smectites and zeolites. Therefore, to link alteration features on Mars to specific physical conditions, the exact identity of the mineral phases present in surface rocks must be known. Moreover, our simulations on closed-system isochemical alteration showed that the fraction of zeolites and silica formed relative to smectite depends on the source mineral altered. Therefore, fractions of these mineral groups present in the Martian soil may be used to better predict source rock characteristics.

  1. Paralavas in the Cretaceous Paraná volcanic province, Brazil - A genetic interpretation of the volcanic rocks containing phenocrysts and glass

    Directory of Open Access Journals (Sweden)

    SÉRGIO B. BAGGIO

    Full Text Available ABSTRACT The occurrences of glassy rocks containing long and curved phenocrysts in the Paraná volcanic province, South America, are here interpreted as paralavas. The large number of thin (0.1-0.5 m dikes and sills of glassy volcanic rocks with hopper, hollow or curved, large crystals of clinopyroxene (up to 10 cm, plagioclase (up to 1 cm, magnetite and apatite are contained in the core of thick (>70 m pahoehoe flows. They are strongly concentrated in the state of Paraná, coincident with the presence of the large number of dikes in the Ponta Grossa arch. These rocks were previously defined as pegmatites, although other names have also been used. A paralava is here interpreted as the product of melting of basaltic rocks following varied, successive processes of sill emplacement in high-kerogen bituminous shale and ascent of the resultant methane. As the gas reached the lower portion of the most recent lava flow of the volcanic pile, the methane reacted with the silicate and oxide minerals of the host volcanic rock (1,000 ºC and thus elevated the local temperature to 1,600 ºC. The affected area of host rock remelted (possibly 75 wt.% and injected buoyantly the central and upper portion of the core. This methane-related mechanism explains the evidence found in the paralavas from this volcanic province, one of the largest in the continents.

  2. Self-sustained vibrations in volcanic areas extracted by Independent Component Analysis: a review and new results

    Directory of Open Access Journals (Sweden)

    E. De Lauro

    2011-12-01

    Full Text Available We investigate the physical processes associated with volcanic tremor and explosions. A volcano is a complex system where a fluid source interacts with the solid edifice so generating seismic waves in a regime of low turbulence. Although the complex behavior escapes a simple universal description, the phases of activity generate stable (self-sustained oscillations that can be described as a non-linear dynamical system of low dimensionality. So, the system requires to be investigated with non-linear methods able to individuate, decompose, and extract the main characteristics of the phenomenon. Independent Component Analysis (ICA, an entropy-based technique is a good candidate for this purpose. Here, we review the results of ICA applied to seismic signals acquired in some volcanic areas. We emphasize analogies and differences among the self-oscillations individuated in three cases: Stromboli (Italy, Erebus (Antarctica and Volcán de Colima (Mexico. The waveforms of the extracted independent components are specific for each volcano, whereas the similarity can be ascribed to a very general common source mechanism involving the interaction between gas/magma flow and solid structures (the volcanic edifice. Indeed, chocking phenomena or inhomogeneities in the volcanic cavity can play the same role in generating self-oscillations as the languid and the reed do in musical instruments. The understanding of these background oscillations is relevant not only for explaining the volcanic source process and to make a forecast into the future, but sheds light on the physics of complex systems developing low turbulence.

  3. Enhancing extraction efficiency of mid-infrared fluorescence in chalcogenide glass via photonic crystal

    Science.gov (United States)

    Zhang, Jun; Zhang, Peiqing; Ma, Beijiao; Dai, Shixun; Zhang, Wei; Nie, Qiuhua

    2016-04-01

    The use of rare earth-doped chalcogenide glass is an attractive method to develop mid-infrared sources. In this work, Er3+-doped chalcogenide glass is prepared, and photonic crystal (PC) pattern is designed to improve the extraction efficiency of light emission from the sample surface. The finite difference time domain simulation shows that the light extraction efficiency from the sample surface can be 1.62 times stronger than that from the sample without PC structure by introducing a simple two-dimensional (2D) PC structure into glass samples. This improvement was the result of the efficient light diffraction on the surface because of the integrated 2D PC. Results in this work offer a potential in developing midinfrared light sources.

  4. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

    The temperature dependence of the viscosity of most glassforming liquids is known to depart significantly from the classical Arrhenius behaviour of simple fluids. The discovery of an unexpected correlation between the extent of this departure and the Poisson ratio of the resulting glass could lead...... to new understanding of glass ageing and viscous liquid dynamics....

  5. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

    The temperature dependence of the viscosity of most glassforming liquids is known to depart significantly from the classical Arrhenius behaviour of simple fluids. The discovery of an unexpected correlation between the extent of this departure and the Poisson ratio of the resulting glass could lead...... to new understanding of glass ageing and viscous liquid dynamics....

  6. Formation of the Yandangshan volcanic-plutonic complex (SE China) by melt extraction and crystal accumulation

    Science.gov (United States)

    Yan, Li-Li; He, Zhen-Yu; Jahn, Bor-ming; Zhao, Zhi-Dan

    2016-12-01

    The association of volcanic and shallow plutonic rocks in caldera may provide important clues to the geochemical evolution of silicic magma systems. The Yandangshan caldera is a typical example of late Mesozoic volcanic-plutonic complex in SE China. It is composed of a series of rhyolitic extrusives and subvolcanic intrusions of porphyritic quartz syenites. In this work, we conducted petrological and geochemical studies, as well as zircon dating, on the coexisting volcanic and plutonic rocks from the Yandangshan caldera. The results of SHRIMP and LA-ICP-MS zircon U-Pb dating revealed that the crystallization of the rhyolitic extrusives and subvolcanic intrusions was contemporaneous within analytical errors and in a short period (104-98 Ma). Geochemically, the volcanic rocks are characterized by high Rb/Sr and Rb/Ba ratios and depletion in Ba, Sr, P, Eu and Ti, while the shallow plutons show high K, Ba, Al, Fe and low Rb/Sr and Rb/Ba ratios with insignificant negative Eu anomalies. The volcanic and plutonic rocks have a similar range of zircon Hf isotopic compositions (εHf(t) = - 10.0 to + 1.5) and TDM2 model ages of 2.10-1.23 Ga. They also have comparable whole-rock Sr and Nd isotopic compositions ((87Sr/86Sr)i = 0.7084-0.7090; εNd(t) = - 7.8 to - 6.5) and zircon oxygen isotopic compositions (δ18O mainly = 4.5 to 6.0‰). We argue that the volcanic-plutonic complex of the Yandangshan caldera was formed by reworking of Paleoproterozoic lower crusts in the eastern Cathaysia block, and that the complex could be linked by fractional crystallization and crystal accumulation in a shallow magma chamber. The volcanic rocks represent the highly fractionated end-member, whereas the subvolcanic intrusions of porphyritic quartz syenites could be the residual crystal mushes. This case study could have a general implication for the genetic relationship between volcanic and shallow plutonic rocks in calderas.

  7. Feasibility of lead extraction from waste Cathode-Ray-Tubes (CRT) funnel glass through a lead smelting process.

    Science.gov (United States)

    Lv, Jianfang; Yang, Hongying; Jin, Zhenan; Ma, Zhiyuan; Song, Yan

    2016-11-01

    A novel and effective process for extracting lead from the hazardous waste Cathode Ray Tubes (CRT) funnel glass is presented. The technological breakthrough of this process is introducing the discarded CRT funnel glass to traditional lead smelting. In this study, the influences of amount of carbon addition, calcium-silicate ratio, temperature, holding time and funnel glass addition on lead extraction efficiency were investigated to determine the optimal operational parameters. With a glass addition of less than 30wt%, a high extraction yield of 97.5% of lead from the mixture of funnel glass and lead slag was successfully obtained by controlling the C/PbO molar ratio, CaO/SiO2 ratio, temperature, treatment time at 0.9, 0.8, 1200°C, 60min, respectively. The main crystalline phases of the residues were calcium silicate slag, and an amorphous glass phase appears at a glass addition more than 30wt%. Thermodynamic calculation shows that the proportion of liquid phase in the slag first increased and then decreased, when the addition of glass is increased, while the viscosity of the slag exhibited a continuous decrease. Thus, based on all the results, it is concluded that the process proposed in this paper is an effective and promising approach for reutilization of obsolete CRT funnel glass. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Safer DNA extraction from plant tissues using sucrose buffer and glass fiber filter.

    Science.gov (United States)

    Takakura, Koh-Ichi; Nishio, Takayuki

    2012-11-01

    For some plant species, DNA extraction and downstream experiments are inhibited by various chemicals such as polysaccharides and polyphenols. This short communication proposed an organic-solvent free (except for ethanol) extraction method. This method consists of an initial washing step with STE buffer (0.25 M sucrose, 0.03 M Tris, 0.05 M EDTA), followed by DNA extraction using a piece of glass fiber filter. The advantages of this method are its safety and low cost. The purity of the DNA solution obtained using this method is not necessarily as high as that obtained using the STE/CTAB method, but it is sufficient for PCR experiments. These points were demonstrated empirically with two species, Japanese speedwell and common dandelion, for which DNA has proven difficult to amplify via PCR in past studies.

  9. Mapping Activity Variations for Ru2O3 in Lunar Volcanic Green Glass Analogs Using Differential Pulse Voltammetry

    Science.gov (United States)

    Malum, K. M.; Colson, R. O.; Sawarynski, M.

    2001-01-01

    Using differential pulse voltammetry, we are mapping variations in activities for NiO and Ru2O3 as a function of compositional variation for compositions centered around an Apollo 15 green glass analog. Additional information is contained in the original extended abstract.

  10. Antimicrobial thin films based on ayurvedic plants extracts embedded in a bioactive glass matrix

    Science.gov (United States)

    Floroian, L.; Ristoscu, C.; Candiani, G.; Pastori, N.; Moscatelli, M.; Mihailescu, N.; Negut, I.; Badea, M.; Gilca, M.; Chiesa, R.; Mihailescu, I. N.

    2017-09-01

    Ayurvedic medicine is one of the oldest medical systems. It is an example of a coherent traditional system which has a time-tested and precise algorithm for medicinal plant selection, based on several ethnopharmacophore descriptors which knowledge endows the user to adequately choose the optimal plant for the treatment of certain pathology. This work aims for linking traditional knowledge with biomedical science by using traditional ayurvedic plants extracts with antimicrobial effect in form of thin films for implant protection. We report on the transfer of novel composites from bioactive glass mixed with antimicrobial plants extracts and polymer by matrix-assisted pulsed laser evaporation into uniform thin layers onto stainless steel implant-like surfaces. The comprehensive characterization of the deposited films was performed by complementary analyses: Fourier transformed infrared spectroscopy, glow discharge optical emission spectroscopy, scanning electron microscopy, atomic force microscopy, electrochemical impedance spectroscopy, UV-VIS absorption spectroscopy and antimicrobial tests. The results emphasize upon the multifunctionality of these coatings which allow to halt the leakage of metal and metal oxides into the biological fluids and eventually to inner organs (by polymer use), to speed up the osseointegration (due to the bioactive glass use), to exert antimicrobial effects (by ayurvedic plants extracts use) and to decrease the implant price (by cheaper stainless steel use).

  11. Extraction technique for the determination of oxygen-18 in water using preevacuated glass vials

    Science.gov (United States)

    Socki, R. A.; Karlsson, H. R.; Gibson, E. K. Jr; Gibson EK, J. r. (Principal Investigator)

    1992-01-01

    The need for a rapid, inexpensive technique for routine 18O/16O extraction from water has arisen recently through applications in the medical sciences and in hydrology. The traditional experimental technique for determining the oxygen isotope composition of water, the CO2-H2O equilibration method, is tedious, time consuming, and involves the use of custom-made glass apparatus. Furthermore, because of potential memory effects from one sample to the next, the glassware needs to be thoroughly cleaned between runs. A few attempts have been made to improve upon the method. Attempts to analyze water directly in the source of the mass spectrometer produced large memory effects and questionable results. Commercially available apparatus for automated extraction of 18O/16O from water is generally prohibitively expensive and often is designed to interface only with the manufacturer's own mass spectrometer. The method described in this paper utilizes inexpensive, off-the-shelf, preevacuated, glass vials. Preevacuated vials have been used by others for the isotopic analysis of breath CO2 and are well tested. The vials can be purchased in bulk from scientific apparatus suppliers at a relatively low cost. These are coupled with a simplified extraction line consisting of a stainless steel syringe needle and a glass cold trap. Vials are filled with CO2 and H2O and shaken in a constant-temperature water bath for at least 90 min. Since the vials are discarded after use, no cleaning is necessary, essentially eliminating any memory effect. Reproducibility is generally better than +/- 0.05%. The only reagents required are gaseous CO2 for equilibration, a dry ice/alcohol mixture for trapping water, and liquid nitrogen for transferring the CO2.

  12. Extraction technique for the determination of oxygen-18 in water using preevacuated glass vials

    Science.gov (United States)

    Socki, R. A.; Karlsson, H. R.; Gibson, E. K. Jr; Gibson EK, J. r. (Principal Investigator)

    1992-01-01

    The need for a rapid, inexpensive technique for routine 18O/16O extraction from water has arisen recently through applications in the medical sciences and in hydrology. The traditional experimental technique for determining the oxygen isotope composition of water, the CO2-H2O equilibration method, is tedious, time consuming, and involves the use of custom-made glass apparatus. Furthermore, because of potential memory effects from one sample to the next, the glassware needs to be thoroughly cleaned between runs. A few attempts have been made to improve upon the method. Attempts to analyze water directly in the source of the mass spectrometer produced large memory effects and questionable results. Commercially available apparatus for automated extraction of 18O/16O from water is generally prohibitively expensive and often is designed to interface only with the manufacturer's own mass spectrometer. The method described in this paper utilizes inexpensive, off-the-shelf, preevacuated, glass vials. Preevacuated vials have been used by others for the isotopic analysis of breath CO2 and are well tested. The vials can be purchased in bulk from scientific apparatus suppliers at a relatively low cost. These are coupled with a simplified extraction line consisting of a stainless steel syringe needle and a glass cold trap. Vials are filled with CO2 and H2O and shaken in a constant-temperature water bath for at least 90 min. Since the vials are discarded after use, no cleaning is necessary, essentially eliminating any memory effect. Reproducibility is generally better than +/- 0.05%. The only reagents required are gaseous CO2 for equilibration, a dry ice/alcohol mixture for trapping water, and liquid nitrogen for transferring the CO2.

  13. Differentiating the Bishop ash bed and related tephra layers by elemental-based similarity coefficients of volcanic glass shards using solution inductively coupled plasma-mass spectrometry (S-ICP-MS)

    Science.gov (United States)

    Knott, J.R.; Sarna-Wojcicki, A. M.; Montanez, I.P.; Wan, E.

    2007-01-01

    Volcanic glass samples from the same volcanic center (intra-source) often have a similar major-element composition. Thus, it can be difficult to distinguish between individual tephra layers, particularly when using similarity coefficients calculated from electron microprobe major-element measurements. Minor/trace element concentrations in glass can be determined by solution inductively coupled plasma mass spectrometry (S-ICP-MS), but have not been shown as suitable for use in large tephrochronologic databases. Here, we present minor/trace-element concentrations measured by S-ICP-MS and compare these data by similarity coefficients, the method commonly used in large databases. Trial samples from the Bishop Tuff, the upper and lower tuffs of Glass Mountain and the tuffs of Mesquite Spring suites from eastern California, USA, which have an indistinguishable major-element composition, were analyzed using S-ICP-MS. The resulting minor/trace element similarity coefficients clearly separated the suites of tephra layers and, in most cases, individual tephra layers within each suite. Comparisons with previous instrumental neutron activation analysis (INAA) elemental measurements were marginally successful. This is important step toward quantitative correlation in large tephrochronologic databases to achieve definitive identification of volcanic glass samples and for high-resolution age determinations. ?? 2007 Elsevier Ltd and INQUA.

  14. Melt extraction in mush zones: The case of crystal-rich enclaves at the Sabatini Volcanic District (central Italy)

    Science.gov (United States)

    Masotta, M.; Mollo, S.; Gaeta, M.; Freda, C.

    2016-04-01

    A peculiar feature of the Sabatini Volcanic District (SVD, central Italy) is the occurrence of crystal-poor pumices and crystal-rich enclaves within the same eruptive host-deposit. The stratigraphic sequence of pumices and enclaves indicates the tapping of a stratified magma chamber, where a crystal-poor phonolitic magma lay on top of a more primitive crystal-rich magma. The crystal-rich enclaves are genetically related to the pumices and record the evolution of a solidification front, in which a more differentiated melt was produced, extracted and eventually erupted. We collected and analyzed crystal-rich enclaves from one of the largest phonolitic eruptions at the SVD and used their petrological and geochemical features to reconstruct magma differentiation and crystal-melt separation in the solidification front. On this basis, three groups of enclaves have been identified: porphyritic enclaves, holocrystalline enclaves and sanidinites. The mineralogical variability faithfully reproduces the spatial and temporal evolution expected of a solidification front, from early-to-intermediate crystallization conditions (porphyritic and holocrystalline type) to the late stage of solidification (sanidinites), in which the percolation of a more differentiated melt through the crystal mush triggered the instability of the solidification front. Results from numerical models indicate that gravitational instability is the most efficient mechanism to explain melt extraction in mush zones of medium-sized (~ 10 km3), short-lived (~ 104 years) magma chambers.

  15. Characterization of Glasses in One Type of Alumina Rich Fly Ash by Chemical Digestion Methods: Implications for Alumina Extraction

    Directory of Open Access Journals (Sweden)

    Lijun Zhao

    2016-01-01

    Full Text Available In recent years, one type of alumina rich fly ash (ARFA with about 50 wt% of alumina has been extensively investigated for alumina extraction in China. Due to the silica in ARFA, alumina extraction would have to generate a huge amount of solid waste. There is a growing interest in the glasses in ARFA, because they are composed mainly of silica and could be removed prior to alumina extraction. In this work, the glasses in ARFA have been investigated by chemical methods, that is, acid and base digestions. The chemical compositions have been measured by XRF for ARFA from the digestion processes. The K2O standard, XRD, and FTIR spectroscopies were successfully used to define the digestions processes, and size analysis and SEM-EDX provided rich information on particle transformations. As a result, acid and base digestion methods were found to produce very similar results for the glasses in ARFA. The K2O standard was attributed to the formation of glasses by illites, and TiO2 and Fe2O3 were proposed to originate from ilmenite in alumina rich coals (ARC. Some implications of the results were also discussed for the alumina extraction from ARFA.

  16. A micro-scale investigation of melt production and extraction in the upper mantle based on silicate melt pockets in ultramafic xenoliths from the Bakony-Balaton Highland Volcanic Field (Western Hungary)

    DEFF Research Database (Denmark)

    Bali, Eniko; Zanetti, A.; Szabo, C.;

    2008-01-01

    Mantle xenoliths in Neogene alkali basalts of the Bakony-Balaton Highland Volcanic Field (Western Hungary) frequently have melt pockets that contain silicate minerals, glass, and often carbonate globules. Textural, geochemical and thermobarometric data indicate that the melt pockets formed at rel...

  17. SUBJOULE DIODE-PUMPED YTTERBIUM-ERBIUM GLASS LASER WITH CAVITY DUMPING FOR CATARACT EXTRACTION

    Directory of Open Access Journals (Sweden)

    A. V. Belikov

    2015-11-01

    Full Text Available Subject of Study. The paper discusses the breadboarding results of compact diode pumped laser. The laser is based on Yb,Er:glass slab active element and frustrated total internal reflection (FTIR shutter and features of the impact of generated pulses at the water-containing media. The transmitter working in cavity dumping mode provides generation of single microsecond pulses or regular trains of these pulses with peak power up to 100 kW and average output power up to 8 W. The laser allows varying output parameters of radiation in wide range and is designed for the usage in technology and biomedical applications. The possibilities of the laser radiation parameters adapting for application in a compact laser cataract extraction complex are examined. Method. The energy efficient for three level active medium method of lasing pulses repetition rate increasing was investigated, which comprises the generation of pulse trains by several FTIR shutter switching on one pump pulse. We carried out analysis of application possibility for microsecond laser pulses with peak power of tens of kilowatts at wavelength of 1,54 μm in the processing of water-containing tissues. The acoustic response on the interaction of radiation with a model environment was studied. Main Results. In the modulation mode of useful (active losses lasing pulses have been obtained with microsecond duration and energy more than 100 mJ and trains of pulses with total energy of 0,5 J at the effective pulse repetition rate of more than 50 Hz. The minimal permissible period of laser pulses in train (300 μs has been established experimentally on the basis of optoacoustic studies. It meets the criteria of operation noninvasiveness consisting in prevention of the risk of posterior lens capsule damage with laser radiation. Practical Relevance. The results obtained with the layout of diode pumped Yb,Er:glass laser with cavity dumping and slab active element are presently record for diode

  18. A glass capillary based microfluidic electromembrane extraction of basic degradation products of nitrogen mustard and VX from water.

    Science.gov (United States)

    Tak, Vijay; Kabra, Ankur; Pardasani, Deepak; Goud, D Raghavender; Jain, Rajeev; Dubey, D K

    2015-12-24

    In this work, a glass capillary based microfluidic electromembrane extraction (μ-EME) was demonstrated for the first time. The device was made by connecting an auxillary borosilicate glass tubing (O.D. 3mm, I.D. 2mm) perpendicular to main borosilicate glass capillary just below one end of the capillary (O.D. 8mm, I.D. 1.2mm). It generated the distorted T-shaped device with inlet '1' and inlet '2' for the introduction of sample and acceptor solutions, respectively. At one end of this device (inlet '2'), a microsyringe containing acceptor solution along with hollow fiber (O.D. 1000μm) was introduced. This configuration creates the micro-channel between inner wall of glass capillary and outer surface of hollow fiber. Sample solution was pumped into the system through another end of glass capillary (inlet '1'), with a micro-syringe pump. The sample was in direct contact with the supported liquid membrane (SLM), consisted of 20% (w/w) di-(2-ethylhexyl)phosphate in 2-nitrophenyl octyl ether immobilized in the pores of the hollow fiber. In the lumen of the hollow fiber, the acceptor phase was present. The driving force for extraction was direct current (DC) electrical potential sustained over the SLM. Highly polar (logP=-2.5 to 1.4) basic degradation products of nitrogen mustard and VX were selected as model analytes. The influence of chemical composition of SLM, extraction time, voltage and pH of donor and acceptor phase were investigated. The model analytes were extracted from 10μL of pure water with recoveries ranging from 15.7 to 99.7% just after 3min of operation time. Under optimized conditions, good limits of detection (2-50ngmL(-1)), linearity (from 5-1000 to 100-1000ngmL(-1)), and repeatability (RSDs below 11.9%, n=3) were achieved. Applicability of the proposed μ-EME was proved by recovering triethanolamine (31.3%) from 10μL of five times diluted original water sample provided by the Organization for the Prohibition of Chemical Weapons during 28th official

  19. Effect of storage conditions on the biological activity of phenolic compounds of blueberry extract packed in glass bottles.

    Science.gov (United States)

    Srivastava, Anita; Akoh, Casimir C; Yi, Weiguang; Fischer, Joan; Krewer, Gerard

    2007-04-04

    Recent research suggests that blueberries are rich in total polyphenols and total anthocyanins. Phenolic compounds are highly unstable and may be lost during processing, particularly when heat treatment is involved. There is no systematic study available providing information on the fate of phenolic compounds during storage and how that affects their biological activity. We provide a systematic evaluation of the changes observed in total polyphenols (TPP), total anthocyanins (TACY), Trolox equivalent antioxidant capacity (TEAC), phenolic acids, and individual anthocyanins of blueberry extract stored in glass bottles and the ability of blueberry extract to inhibit cell proliferation. The extract was stored at different temperatures (-20 +/- 1, 6 +/- 1, 23 +/- 1, and 35 +/- 1 degrees C). Two cultivars, Tifblue and Powderblue, were chosen for the study. The recoveries of TPP, TACY, and TEAC in blueberry extract after pressing and heating were approximately 25, approximately 29, and approximately 69%, respectively, for both cultivars. The recovery of gallic acid, catechin, and quercetin was approximately 25%. Ferulic acid was not detected in the final extract in both Tifblue and Powderblue cultivars. The recovery of peonidin, malvidin, and cyanidin glycosides was approximately 20% in the final extract in both cultivars. Losses due to storage were less when compared with initial losses due to processing. At -20 degrees C, no statistically significant loss of TPP, TACY, and TEAC was observed up to 30 days (P blueberry extract in order to retain the bioactive components.

  20. Nature, Source and Composition of Volcanic Ash in Surficial Sediments Around the Zhongsha Islands

    Institute of Scientific and Technical Information of China (English)

    YAN Quanshu; SHI Xuefa; WANG Xinyu

    2008-01-01

    Volcanic detrital sediments are a unique indicator for reconstructing the petrogenetie evolution of submarine volcanic terrains. Volcanic ash in surficial sediments around the Zhongsha Islands includes three kinds of volcanogenic detritus, i.e., brown volcanic glass, colorless volcanic glass and volcanic scoria. The major element characteristics show that bimodal volcanic activity may have taken place in the northern margin of the South China Sea, with brown volcanic glass and colorless volcanic glass repre-senting the maric end-member and felsie end-member, respectively. Fractional crystallization is the main process for magma evolu-tion. The nature of the volcanic activity implies that the origin of volcanic activity was related to extensional tectonic settings, which is corresponding to an extensional geodynamie setting in the Xisha Trench, and supports the notion, which is based on geophysical data and petrology, that there may exist a mantle plume around the Hainan Island.

  1. Catastrophic volcanism

    Science.gov (United States)

    Lipman, Peter W.

    1988-01-01

    Since primitive times, catastrophes due to volcanic activity have been vivid in the mind of man, who knew that his activities in many parts of the world were threatened by lava flows, mudflows, and ash falls. Within the present century, increasingly complex interactions between volcanism and the environment, on scales not previously experienced historically, have been detected or suspected from geologic observations. These include enormous hot pyroclastic flows associated with collapse at source calderas and fed by eruption columns that reached the stratosphere, relations between huge flood basalt eruptions at hotspots and the rifting of continents, devastating laterally-directed volcanic blasts and pyroclastic surges, great volcanic-generated tsunamis, climate modification from volcanic release of ash and sulfur aerosols into the upper atmosphere, modification of ocean circulation by volcanic constructs and attendent climatic implications, global pulsations in intensity of volcanic activity, and perhaps triggering of some intense terrestrial volcanism by planetary impacts. Complex feedback between volcanic activity and additional seemingly unrelated terrestrial processes likely remains unrecognized. Only recently has it become possible to begin to evaluate the degree to which such large-scale volcanic processes may have been important in triggering or modulating the tempo of faunal extinctions and other evolutionary events. In this overview, such processes are examined from the viewpoint of a field volcanologist, rather than as a previous participant in controversies concerning the interrelations between extinctions, impacts, and volcanism.

  2. Extraction of glass-wafers electrical properties based on S-parameters measurements of coplanar waveguides

    OpenAIRE

    Mendes, P. M.; Polyakov, A.; Bartek, M.; Burghartz, J.N.; Correia, J.H.

    2003-01-01

    The measured S-parameters of a coplanar waveguide (CPW) propagating the dominant mode were used to obtain the electrical permittivity and the dielectric loss tangent of three different glass wafers: non-alkaline Schott AF45, Corning Pyrex #7740 and Hoya SD-2. These properties were obtained up to 10 GHz. The obtained values were used together with the CPW model in ADS to obtain the simulated S-parameters for the used CPW cell. The obtained results shows good agreement b...

  3. The Use of High-Resolution Pléiades Images to Extract Volcanic-Cloud Top Heights and Plume Elevation Models: examples on Mount Etna (Italy) and Mount Ontake (Japan)

    Science.gov (United States)

    de Michele, Marcello; Raucoules, Daniel; Corradini, Stefano; Merucci, Luca; spinetti, claudia

    2017-04-01

    Accurate and spatially-detailed knowledge of Volcanic Cloud Top Height (VCTH) and velocity is crucial in volcanology. As an example, the ash/gas dispersion in the atmosphere, their impact and lifetime around the globe, greatly depends on the injection altitude. The VCTH is critical for ash dispersion modelling and air traffic security. Furthermore, the volcanic plume height during explosive volcanism is the primary parameter for estimating mass eruption rate. Satellite remote sensing offers a comprehensive and safe way to estimate VCTH. Recently, it has been shown that high spatial resolution optical imagery from Landsat-8 OLI sensor can be used to extract Volcanic Cloud Top Height with a precision of 250 meters and an accuracy or 300m (de Michele et al., 2016). This method allows to extract a Plume Elevation Model (PEM) by jointly measuring the parallax between two optical bands acquired with a time lag varying from 0.1 to 2.5 seconds depending on the bands chosen and the sensors employed. The measure of the parallax is biased because the volcanic cloud is moving between the two images acquisitions, even if the time lag is short. The precision of our measurements is enhanced by compensating the parallax by measuring the velocity of the volcanic cloud in the perpendicular-to-epipolar direction (which is height independent) and correcting the initial parallax measurement. In this study, we push this methodology forward. We apply it to the very high spatial resolution Pleiades data (1m pixel spacing) provided by the French Space Agency (CNES). We apply the method on Mount Etna, during the 05 September 2015 eruptive episode and on Mount Ontake eruption occurring on 30 September 2014. We are able to extract VCTH as a PEM with high spatial resolution and improved precision. Since Pléiades has an improved revisit time (1day), our method has potential for routine monitoring of volcanic plumes in clear sky conditions and when the VCTH is higher than meteo clouds.

  4. Surface functionalization of bioactive glasses with natural molecules of biological significance, part II: Grafting of polyphenols extracted from grape skin

    Science.gov (United States)

    Zhang, Xin; Ferraris, Sara; Prenesti, Enrico; Verné, Enrica

    2013-12-01

    Polyphenols, as one of the most important family of phytochemicals protective substances from grape fruit, possess various biological activities and health-promoting benefits, for example: inhibition of some degenerative diseases, cardiovascular diseases and certain types of cancers, reduction of plasma oxidative stress and slowing aging. The combination of polyphenols and biomaterials may have good potential to reach good bioavailability and controlled release, as well as to give biological signaling properties to the biomaterial surfaces. In this research, conventional solvent extraction was developed for obtaining polyphenols from dry grape skins. The Folin&Ciocalteu method was used to determine the amount of total polyphenols in the extracts. Surface functionalization of two bioactive glasses (SCNA and CEL2) was performed by grafting the extracted polyphenols on their surfaces. The effectiveness of the functionalization was tested by UV spectroscopy, which analyzes the amount of polyphenols in the uptake solution (before and after functionalization) and on solid samples, and XPS, which analyzes the presence of phenols on the material surface.

  5. Influence of anisotropy of magnetic susceptibility (AMS) on paleomagnetic sampling in volcanic glasses: a case study on rheomorphic ignimbrites of the Yellowstone hotspot-track, southern Idaho

    Science.gov (United States)

    Finn, D.; Coe, R. S.; Murphy, J.; Bodiford, S.; Kelly, H.; Foster, S.; Spinardi, F.; Reichow, M. K.; Knott, T.; Branney, M. J.

    2012-12-01

    Large-scale explosive volcanism, associated with the Yellowstone hotspot, occurred in the central Snake River Plain between 12.5-8 Ma. It is characterized by unusually high-temperature, intensely welded, rheomorphic rhyolitic ignimbrites, typical of what is now known as 'Snake River (SR)-type volcanism'. Individual eruption volumes likely exceed 450 km3 but are poorly known due to the difficulty of correlating units between widely spaced (50-200 km) exposures along the north and south of the plain, when some occurred too close-spaced in time for radiometric resolution. Our goal is to use a combination of paleomagnetic, petrographic, chemical and field characterization to establish robust correlations, allowing us to develop a regional stratigraphy, and constrain ignimbrite eruption volumes and frequencies. This presentation focuses on how to sample rheomorphic, SR-type ignimbrites for paleomagnetic studies given the potential effects of hot, rheomorphic deformation. Individual SR-type ignimbrite cooling-units have an upper and lower glassy margins (vitrophyre) enclosing a lithoidal (microcrystalline) zone. We have sampled dozens of ignimbrites in detail and have observed that the lithoidal interiors are preferable to the glassy margins for paleomagnetic studies. We hypothesize that the glassy margins retain an anisotropic fabric related to emplacement compaction and/or shearing that affects their ability to accurately record the magnetic field during cooling. In the lithoidal interiors this anisotropic fabric was overprinted by continued grain growth and/or alteration and, therefore, may accurately record the paleomagnetic field. Paleomagnetic samples from vitrophyres generally have a higher anisotropy in magnetic susceptibility than lithoidal samples. The remanent magnetic directions recorded in samples with high anisotropy of magnetic susceptibility are often deflected away from the site mean and closer to the plane of easy magnetic susceptibility. Since the

  6. Alteration of glass as a possible source of clay minerals on Mars

    Science.gov (United States)

    Gooding, J. L.; Keil, K.

    1978-01-01

    Thermodynamic calculations show that, under present Martian surface conditions, favorable gas-solid weathering products of feldspar glasses should include beidellites (clays of the montmorillonite series) + carbonates + quartz. The gas-solid weathering of mafic silicate glass ( of volcanic or impact origin) may similarly favor the production of metastable Fe-rich montmorillonite clays. Simple mass-balance calculations suggest that gas-solid weathering of Martian proto-regolith containing 10% glass could conceivably produce a global blanket of clays at a rate of at least 0.4 cm/b.y. The production rate should be expected to increase significantly with the glass content and rate of reworking of the proto-regolith and with the availability of water. Complete extraction of altered glass from a lunar-like proto-regolith might yield a global Martian clay blanket about 10-100 cm in thickness.

  7. Evaluation of plutonium(IV) extraction rate between nitric acid and tri-n-butylphosphate solution using a glass chip microchannel.

    Science.gov (United States)

    Yamamoto, Masahiko; Taguchi, Shigeo; Sato, Soichi; Surugaya, Naoki

    2015-05-01

    Extraction of Pu(IV) with tri-n-butylphosphate is performed using a glass chip microchannel to evaluate the extraction rate. Two-phase flow forms in the microchannel by introducing a solution of Pu(IV) and tri-n-butylphosphate with flow rates above 5 μL/min. The Pu(IV) extraction reaction proceeds at the interface between the two phases. To evaluate the extraction rate, the contact time between the two phases is varied from 0.48 to 4.8 s by changing the confluent length of the microchannel and the flow rate. The Pu concentration of each phase collected from the microchannel is measured with an alpha liquid scintillation counter, and the contact time dependence of Pu(IV) extraction is obtained. An extraction model based on diffusion in the microchannel and the reaction at the interface is proposed and applied to determine the extraction rate. The extraction process is assumed to follow pseudo-first-order kinetics, and the extraction rate constant of Pu(IV) is determined to be 1.5 × 10(-2) cm/s. The investigation demonstrates that a microfluidic device can be a new tool to determine Pu(IV) extraction rates.

  8. Volcanic rock properties control sector collapse events

    Science.gov (United States)

    Hughes, Amy; Kendrick, Jackie; Lavallée, Yan; Hornby, Adrian; Di Toro, Giulio

    2017-04-01

    Volcanoes constructed by superimposed layers of varying volcanic materials are inherently unstable structures. The heterogeneity of weak and strong layers consisting of ash, tephra and lavas, each with varying coherencies, porosities, crystallinities, glass content and ultimately, strength, can promote volcanic flank and sector collapses. These volcanoes often exist in areas with complex regional tectonics adding to instability caused by heterogeneity, flank overburden, magma movement and emplacement in addition to hydrothermal alteration and anomalous geothermal gradients. Recent studies conducted on the faulting properties of volcanic rocks at variable slip rates show the rate-weakening dependence of the friction coefficients (up to 90% reduction)[1], caused by a wide range of factors such as the generation of gouge and frictional melt lubrication [2]. Experimental data from experiments conducted on volcanic products suggests that frictional melt occurs at slip rates similar to those of plug flow in volcanic conduits [1] and the bases of mass material movements such as debris avalanches from volcanic flanks [3]. In volcanic rock, the generation of frictional heat may prompt the remobilisation of interstitial glass below melting temperatures due to passing of the glass transition temperature at ˜650-750 ˚C [4]. In addition, the crushing of pores in high porosity samples can lead to increased comminution and strain localisation along slip surfaces. Here we present the results of friction tests on both high density, glass rich samples from Santaguito (Guatemala) and synthetic glass samples with varying porosities (0-25%) to better understand frictional properties underlying volcanic collapse events. 1. Kendrick, J.E., et al., Extreme frictional processes in the volcanic conduit of Mount St. Helens (USA) during the 2004-2008 eruption. J. Structural Geology, 2012. 2. Di Toro, G., et al., Fault lubrication during earthquakes. Nature, 2011. 471(7339): p. 494-498. 3

  9. Volcanic gas

    Science.gov (United States)

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  10. Clinical Effect of Antioxidant Glasses Containing Extracts of Medicinal Plants in Patients with Dry Eye Disease: A Multi-Center, Prospective, Randomized, Double-Blind, Placebo-Controlled Trial.

    Science.gov (United States)

    Choi, Won; Kim, Jae Chan; Kim, Won Soo; Oh, Han Jin; Yang, Jee Myung; Lee, Jee Bum; Yoon, Kyung Chul

    2015-01-01

    To investigate the clinical efficacy and safety of wearable antioxidant glasses containing extracts of medicinal plants in patients with mild dry eye disease (DED). Fifty patients with mild DED were randomly assigned to wear either extracts of antioxidant medicinal plants containing (N = 25) or placebo glasses (N = 25). Patients wore the glasses for 15 min three times daily. The ocular surface disease index (OSDI) score, tear film break up time (BUT), and Schirmer's test were evaluated and compared within the group and between the groups at baseline, 4 weeks, and 8 weeks after treatment. OSDI score and tear film BUT were significantly improved in the treatment group at 4 and 8 weeks after wearing glasses (all P plants were effective in improving in DED both subjectively and objectively. Wearing antioxidants glasses might be a safe and adjunctive therapeutic option for DED. ISRCTN registry 71217488.

  11. Volcanic Catastrophes

    Science.gov (United States)

    Eichelberger, J. C.

    2003-12-01

    The big news from 20th century geophysics may not be plate tectonics but rather the surprise return of catastrophism, following its apparent 19th century defeat to uniformitarianism. Divine miracles and plagues had yielded to the logic of integrating observations of everyday change over time. Yet the brilliant interpretation of the Cretaceous-Tertiary Boundary iridium anomaly introduced an empirically based catastrophism. Undoubtedly, decades of contemplating our own nuclear self-destruction played a role in this. Concepts of nuclear winter, volcanic winter, and meteor impact winter are closely allied. And once the veil of threat of all-out nuclear exchange began to lift, we could begin to imagine slower routes to destruction as "global change". As a way to end our world, fire is a good one. Three-dimensional magma chambers do not have as severe a magnitude limitation as essentially two-dimensional faults. Thus, while we have experienced earthquakes that are as big as they get, we have not experienced volcanic eruptions nearly as great as those preserved in the geologic record. The range extends to events almost three orders of magnitude greater than any eruptions of the 20th century. Such a calamity now would at the very least bring society to a temporary halt globally, and cause death and destruction on a continental scale. At maximum, there is the possibility of hindering photosynthesis and threatening life more generally. It has even been speculated that the relative genetic homogeneity of humankind derives from an evolutionary "bottleneck" from near-extinction in a volcanic cataclysm. This is somewhat more palatable to contemplate than a return to a form of Original Sin, in which we arrived at homogeneity by a sort of "ethnic cleansing". Lacking a written record of truly great eruptions, our sense of human impact must necessarily be aided by archeological and anthropological investigations. For example, there is much to be learned about the influence of

  12. The anti-adherence effect of Piper betle and Psidium guajava extracts on the adhesion of early settlers in dental plaque to saliva-coated glass surfaces.

    Science.gov (United States)

    Razak, Fathilah Abdul; Rahim, Zubaidah Haji Abd

    2003-12-01

    The aqueous extracts of Piper betle and Psidium guajava were prepared and tested for their anti-adherence effect on the adhesion of early plaque settlers (Strep. mitis, Strep. sanguinis and Actinomyces sp.). The saliva-coated glass surfaces were used to simulate the pellicle-coated enamel surface in the oral cavity. Our results showed that the anti-adherence activities of Piper betle and Psidium guajava extracts towards the bacteria were different between the bacterial species. Psidium guajava was shown to have a slightly greater anti-adherence effect on Strep. sanguinis by 5.5% and Actinomyces sp. by 10% and a significantly higher effect on Strep. mitis (70%) compared to Piper betle. The three bacterial species are known to be highly hydrophobic, and that hydrophobic bonding seemed to be an important factor in their adherence activities. It is therefore suggested that the plant extracts, in expressing their anti-adherence activities, could have altered the hydrophobic nature of the bonding between the bacteria and the saliva-coated glass surfaces.

  13. Volcanic ash particles as carriers of remanent magnetization in deep-sea sediments from the Kerguelen Plateau

    Science.gov (United States)

    Heider, Franz; Ko¨rner, Ulrike; Bitschene, Peter

    1993-07-01

    Carbonate sediments from the Kerguelen Plateau (ODP Leg 120) of Eocene to Pliocene age were investigated with rock magnetic, petrographic and geochemical methods to determine the carriers of remanent magnetization. Magnetic methods showed that the major magnetic minerals were titanomagnetites slightly larger than single domain particles. Submicrometre to micrometre-size grains of titanomagnetite were identified as inclusions in volcanic glass particles or as crystals in lithic clasts. Volcanic fallout ash particles formed the major fraction of the magnetic extract from each sediment sample. Three groups of volcanic ashes were identified: trachytic ashes, basaltic ashes with sideromelane and tachylite shards, and palagonitic ashes. These three groups could be equally well defined based on their magnetic hysteresis properties and alternating field demagnetization curves. The highest coercivities of all samples were found for the tachylite, due to the submicrometre-size titanomagnetite inclusions in the matrix. Trachytic ashes had intermediate magnetic properties between the single-domain-type tachylites and the palagonitic (altered) basaltic ashes with low coercivities. Samples which contained mixtures of these different volcanic ashes could be distinguished from the three types of ashes based on their magnetic characteristics. There was neither evidence of biogenic magnetofossils in the transmission electron micrographs nor did we find magnetic particles derived from continental Antarctica. The presence of dispersed volcanic fallout ashes between visible ash layers suggests continuous explosive volcanic activity on the Kerguelen Plateau in the South Indian Ocean since the early Eocene. The continuous fallout of volcanic ash from explosive volcanism on the Kerguelen Archipelago is the source of the magnetic particles and thus responsible for the magnetostratigraphy of the nannofossil oozes drilled during Leg 120.

  14. Identifying the AD 1257 Salamas volcanic event from micron-size tephra composition in two East Antarctic ice cores

    Science.gov (United States)

    Petit, Jean Robert; Narcisi, Biancamaria; Batanova, Valentina G.; Joël, Savarino; Komorowski, Jean Christophe; Michel, Agnes; Metrich, Nicole; Besson, Pascale; Vidal, Celine; Sobolev, Alexander V.

    2016-04-01

    A wealth of valuable data about the history of explosive volcanic history can be extracted from polar ice successions. Both the volatile by-products and the solid silicate (tephra) components of volcanic plumes can be incorporated into snow layers, providing tools for chronostratigraphic correlations and for interpretation of climate-volcanism interactions. Volcanic events from low-latitude regions are of particular interest as the related sulphate aerosol travelling through the stratosphere can reach the polar sheets forming inter-hemispheric (Greenland and Antarctica) signals preserved in the ice. Within the glaciological record of globally significant volcanic markers, the AD1259 signal represents one of most prominent events over the last thousands years. Its source has been long debated. On the basis of recent field investigations (Lavigne et al., 2013; Vidal et al., 2015), it has been proposed that Mount Samalas on Lombok Island (Indonesia) represents the source responsible for the polar event. With the goal of bringing distal tephrochronological evidence to source identification, we have attempted to identify volcanic ash associated to the AD 1259 sulphate pulse. To this purpose we used firn and ice-core samples from two East Antarctic Plateau sites: Concordia-Dome C (75°06' S, 123°20' E, 3233 m) and Talos Dome (72°49'S, 159°11'E, 2315 m). Our high-resolution studies included sample processing in a Class 100 clean room using established ultra-clean procedures for insoluble microparticle analyses, Coulter counter grain size measurements, scanning electron microscope observations and the geochemical (major elements) composition from the recently set ISTERRE Jeol JXA 8230 Superprobe and calibrated for small particles analysis. Despite the difficulty of studying such minute fragments, within both cores we located and characterised multiple tiny (micron-size) glass shards concomitant with the volcanic peak. We present preliminary results alongside comparison

  15. Sedimentary response to volcanic activity in the Okinawa Trough since the last deglaciation

    Institute of Scientific and Technical Information of China (English)

    蒋富清; 李安春; 李铁刚

    2010-01-01

    To investigate the relationship between volcanic activity and sediment record on regional and temporal scales,158 surface sediment samples were collected from the East China Sea Shelf to the northern Okinawa Trough (OT),and two cores recovered in the northern and southern OT,respectively.Mineralogy,grain-size,and geochemical analyses of those samples show that:1) volcanic glass,volcanic-type pyroxene,hypersthenes,and magnetite increase in sediment influenced by volcanic activity;2) sediment grain sizes (and...

  16. Clinical Effect of Antioxidant Glasses Containing Extracts of Medicinal Plants in Patients with Dry Eye Disease: A Multi-Center, Prospective, Randomized, Double-Blind, Placebo-Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Won Choi

    Full Text Available To investigate the clinical efficacy and safety of wearable antioxidant glasses containing extracts of medicinal plants in patients with mild dry eye disease (DED.Fifty patients with mild DED were randomly assigned to wear either extracts of antioxidant medicinal plants containing (N = 25 or placebo glasses (N = 25. Patients wore the glasses for 15 min three times daily. The ocular surface disease index (OSDI score, tear film break up time (BUT, and Schirmer's test were evaluated and compared within the group and between the groups at baseline, 4 weeks, and 8 weeks after treatment.OSDI score and tear film BUT were significantly improved in the treatment group at 4 and 8 weeks after wearing glasses (all P < 0.001. Compared to the placebo group, the OSDI scores were significantly lower in the treatment group at 8 weeks (P = 0.007. The results of the Schirmer's test showed significant improvement in the treatment group at 4 weeks (P = 0.035, however there were no significant differences between the other groups or within the groups. No adverse events were reported during the study.Antioxidant glasses containing extracts of medicinal plants were effective in improving in DED both subjectively and objectively. Wearing antioxidants glasses might be a safe and adjunctive therapeutic option for DED.ISRCTN registry 71217488.

  17. Volcanic hazard management in dispersed volcanism areas

    Science.gov (United States)

    Marrero, Jose Manuel; Garcia, Alicia; Ortiz, Ramon

    2014-05-01

    Traditional volcanic hazard methodologies were developed mainly to deal with the big stratovolcanoes. In such type of volcanoes, the hazard map is an important tool for decision-makers not only during a volcanic crisis but also for territorial planning. According to the past and recent eruptions of a volcano, all possible volcanic hazards are modelled and included in the hazard map. Combining the hazard map with the Event Tree the impact area can be zoned and defining the likely eruptive scenarios that will be used during a real volcanic crisis. But in areas of disperse volcanism is very complex to apply the same volcanic hazard methodologies. The event tree do not take into account unknown vents, because the spatial concepts included in it are only related with the distance reached by volcanic hazards. The volcanic hazard simulation is also difficult because the vent scatter modifies the results. The volcanic susceptibility try to solve this problem, calculating the most likely areas to have an eruption, but the differences between low and large values obtained are often very small. In these conditions the traditional hazard map effectiveness could be questioned, making necessary a change in the concept of hazard map. Instead to delimit the potential impact areas, the hazard map should show the expected behaviour of the volcanic activity and how the differences in the landscape and internal geo-structures could condition such behaviour. This approach has been carried out in La Palma (Canary Islands), combining the concept of long-term hazard map with the short-term volcanic scenario to show the expected volcanic activity behaviour. The objective is the decision-makers understand how a volcanic crisis could be and what kind of mitigation measurement and strategy could be used.

  18. The trace-element characteristics of Aegean and Aeolian volcanic arc marine tephra

    Science.gov (United States)

    Clift, Peter; Blusztajn, Jerzy

    1999-10-01

    High-silica volcanic ashes are found within deep-sea sediments throughout the Eastern Mediterranean. Although coring by Ocean Drilling Program has penetrated Lower Pliocene (˜4 Ma) sediments, few ashes older than 400 k.y. have been recovered, suggesting a young initiation to subaerial Aegean Arc volcanism. Ashes derived from the Aegean volcanic front were cored south and east of the arc, and are typified by medium-K, calc-alkaline major-element compositions, contrasting with high-K ashes from the Aeolian Arc found in the Ionian Sea and as far east as Crete. Ion microprobe analysis of individual glass shards shows that all the ashes have a light rare earth element (LREE)-enriched pattern after normalizing against a chondrite standard. Aeolian Arc-derived ashes show greater enrichment than those from the Aegean area. Within the latter set, two groups are discernible, a mildly enriched set similar to the volcanoes of the arc volcanic front, and a more enriched group corresponding to lavas from the backarc region or possible from western Anatolia. Multi-element `spider diagrams' also show a bimodal division of enriched and depleted Aegean ashes, possibly caused by source depletion due to melt extraction in the Aegean backarc followed by remelting under the volcanic front. Relative Nb depletion, a characteristic of arc volcanism, is seen to be modest in Aegean and non-existent in Aeolian ashes. Using B/Be as a proxy for the flux of material from the subducting slab, this influence is seen to be low in the Aeolian Arc but higher than at Vesuvius. B/Be is higher again in the Aegean Arc. These differences may reflect the rate of subduction in each system. Data suggest caution is required when correlating ashes solely on the basis of major elements, as alkaline ashes from the central part of the study may be derived from Italy or from the Aegean backarc.

  19. Friction in volcanic environments

    Science.gov (United States)

    Kendrick, Jackie E.; Lavallée, Yan

    2016-04-01

    Volcanic landscapes are amongst the most dynamic on Earth and, as such, are particularly susceptible to failure and frictional processes. In rocks, damage accumulation is frequently accompanied by the release of seismic energy, which has been shown to accelerate in the approach to failure on both a field and laboratory scale. The point at which failure occurs is highly dependent upon strain-rate, which also dictates the slip-zone properties that pertain beyond failure, in scenarios such as sector collapse and pyroclastic flows as well as the ascent of viscous magma. High-velocity rotary shear (HVR) experiments have provided new opportunities to overcome the grand challenge of understanding faulting processes during volcanic phenomena. Work on granular ash material demonstrates that at ambient temperatures, ash gouge behaves according to Byerlee's rule at low slip velocities, but is slip-weakening, becoming increasingly lubricating as slip ensues. In absence of ash along a slip plane, rock-rock friction induces cataclasis and heating which, if sufficient, may induce melting (producing pseudotachylyte) and importantly, vesiculation. The viscosity of the melt, so generated, controls the subsequent lubrication or resistance to slip along the fault plane thanks to non-Newtonian suspension rheology. The shear-thinning behaviour and viscoelasticity of frictional melts yield a tendency for extremely unstable slip, and occurrence of frictional melt fragmentation. This velocity-dependence acts as an important feedback mechanism on the slip plane, in addition to the bulk composition, mineralogy and glass content of the magma, that all influence frictional behaviour. During sector collapse events and in pyroclastic density currents it is the frictional properties of the rocks and ash that, in-part, control the run-out distance and associated risk. In addition, friction plays an important role in the eruption of viscous magmas: In the conduit, the rheology of magma is integral

  20. Volcanic hazard assessment in monogenetic volcanic fields

    OpenAIRE

    Bartolini, Stefania

    2014-01-01

    [eng] One of the most important tasks of modern volcanology, which represents a significant socio-economic implication, is to conduct hazard assessment in active volcanic systems. These volcanological studies are aimed at hazard that allows to constructing hazard maps and simulating different eruptive scenarios, and are mainly addressed to contribute to territorial planning, definition of emergency plans or managing volcanic crisis. The impact of a natural event, as a volcanic eruption, can s...

  1. Glass bead cultivation of fungi

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, H.

    2013-01-01

    Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads that allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum...... and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier...... to specific nutrient factors. •Fungal growth on glass beads eases and improves fungal RNA extraction....

  2. Volcanic ash plume identification using polarization lidar: Augustine eruption, Alaska

    Science.gov (United States)

    Sassen, Kenneth; Zhu, Jiang; Webley, Peter W.; Dean, K.; Cobb, Patrick

    2007-01-01

    During mid January to early February 2006, a series of explosive eruptions occurred at the Augustine volcanic island off the southern coast of Alaska. By early February a plume of volcanic ash was transported northward into the interior of Alaska. Satellite imagery and Puff volcanic ash transport model predictions confirm that the aerosol plume passed over a polarization lidar (0.694 mm wavelength) site at the Arctic Facility for Atmospheric Remote Sensing at the University of Alaska Fairbanks. For the first time, lidar linear depolarization ratios of 0.10 – 0.15 were measured in a fresh tropospheric volcanic plume, demonstrating that the nonspherical glass and mineral particles typical of volcanic eruptions generate strong laser depolarization. Thus, polarization lidars can identify the volcanic ash plumes that pose a threat to jet air traffic from the ground, aircraft, or potentially from Earth orbit.

  3. Experimental generation of volcanic lightning

    Science.gov (United States)

    Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel; Kueppers, Ulrich; Scheu, Bettina; Dingwell, Donald B.

    2014-05-01

    Ash-rich volcanic plumes that are responsible for injecting large quantities of aerosols into the atmosphere are often associated with intense electrical activity. Direct measurement of the electric potential at the crater, where the electric activity in the volcanic plume is first observed, is severely impeded, limiting progress in its investigation. We have achieved volcanic lightning in the laboratory during rapid decompression experiments of gas-particle mixtures under controlled conditions. Upon decompression (from ~100 bar argon pressure to atmospheric pressure), loose particles are vertically accelerated and ejected through a nozzle of 2.8 cm diameter into a large tank filled with air at atmospheric conditions. Because of their impulsive character, our experiments most closely represent the conditions encountered in the gas-thrust region of the plume, when ash is first ejected from the crater. We used sieved natural ash with different grain sizes from Popocatépetl (Mexico), Eyjafjallajökull (Iceland), and Soufrière Hills (Montserrat) volcanoes, as well as micrometric glass beads to constrain the influence of material properties on lightning. We monitored the dynamics of the particle-laden jets with a high-speed camera and the pressure and electric potential at the nozzle using a pressure transducer and two copper ring antennas connected to a high-impedance data acquisition system, respectively. We find that lightning is controlled by the dynamics of the particle-laden jet and by the abundance of fine particles. Two main conditions are required to generate lightning: 1) self-electrification of the particles and 2) clustering of the particles driven by the jet fluid dynamics. The relative movement of clusters of charged particles within the plume generates the gradient in electrical potential, which is necessary for lightning. In this manner it is the gas-particle dynamics together with the evolving particle-density distribution within different regions of

  4. Volcanic ash: What it is and how it forms

    Energy Technology Data Exchange (ETDEWEB)

    Heiken, G.

    1991-09-13

    There are four basic eruption processes that produce volcanic ash: (1) decompression of rising magma, gas bubble growth, and fragmentation of the foamy magma in the volcanic vent (magmatic), (2) explosive mixing of magma with ground or surface water (hydrovolcanic), (3) fragmentation of country rock during rapid expansion of steam and/or hot water (phreatic), and (4) breakup of lava fragments during rapid transport from the vent. Variations in eruption style and the characteristics of volcanic ashes produced during explosive eruptions depend on many factors, including magmatic temperature, gas content, viscosity and crystal content of the magma before eruption, the ratio of magma to ground or surface water, and physical properties of the rock enclosing the vent. Volcanic ash is composed of rock and mineral fragments, and glass shards, which is less than 2 mm in diameter. Glass shard shapes and sizes depend upon size and shape of gas bubbles present within the magma immediately before eruption and the processes responsible for fragmentation of the magma. Shards range from slightly curved, thin glass plates, which were broken from large, thin-walled spherical bubble walls, to hollow needles broken from pumiceous melts containing gas bubbles stretched by magma flow within the volcanic vent. Pumice fragments make up the coarser-grained portions of the glass fraction. Particle sizes range from meters for large blocks expelled near the volcanic vent to nanometers for fine ash and aerosol droplets within well-dispersed eruption plumes. 18 refs., 6 figs., 1 tab.

  5. Naturally occurring glasses: analogues for radioactive waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.C.; Haaker, R.F.

    1979-04-01

    Volcanic glasses are very often altered by weathering and leaching and recrystallize to their fine-grained equivalents (rhyolites, felsites). The oldest volcanic glasses are dated at 40 million years before the present, but the majority are much younger. Devitrification textures was produced experimentally; and hydration rates for volcanic glasses were determined as a function of composition, temperature, and climate. Presence of water and temperature are the most important rate controlling variables. Even material that may still be described as glassy often exhibits evidence of alteration and recrystallization. Of the volcanic glasses that are preserved in the geologic record, it would be rare to describe such a glass as pristine. Despite the common alteration and recrystallization effects observed in volcanic glasses, glasses formed as a result of impact, tektites and lunar glasses, may occur in substantially unaltered form. In the case of tektites, their resistance to alteration is a result of their high SiO/sub 2/ content and low alkali content. Lunar glasses have been preserved for hundreds of millions of years because they exist in an environment with a low oxygen fugacity and an extremely low water vapor partial presssure. Thus one might expect glasses of particular compositions or in specific types of environment to be stable for long periods of time. These conclusions are applied to radioactive waste disposal over several time periods (0-30h, 30h-20y, 20-200y).

  6. Naturally occurring glasses: analogues for radioactive waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.C.; Haaker, R.F.

    1979-04-01

    Volcanic glasses are very often altered by weathering and leaching and recrystallize to their fine-grained equivalents (rhyolites, felsites). The oldest volcanic glasses are dated at 40 million years before the present, but the majority are much younger. Devitrification textures was produced experimentally; and hydration rates for volcanic glasses were determined as a function of composition, temperature, and climate. Presence of water and temperature are the most important rate controlling variables. Even material that may still be described as glassy often exhibits evidence of alteration and recrystallization. Of the volcanic glasses that are preserved in the geologic record, it would be rare to describe such a glass as pristine. Despite the common alteration and recrystallization effects observed in volcanic glasses, glasses formed as a result of impact, tektites and lunar glasses, may occur in substantially unaltered form. In the case of tektites, their resistance to alteration is a result of their high SiO/sub 2/ content and low alkali content. Lunar glasses have been preserved for hundreds of millions of years because they exist in an environment with a low oxygen fugacity and an extremely low water vapor partial presssure. Thus one might expect glasses of particular compositions or in specific types of environment to be stable for long periods of time. These conclusions are applied to radioactive waste disposal over several time periods (0-30h, 30h-20y, 20-200y).

  7. Energetics of glass fragmentation: Experiments on synthetic and natural glasses

    Science.gov (United States)

    Kolzenburg, S.; Russell, J. K.; Kennedy, L. A.

    2013-11-01

    Natural silicate glasses are an essential component of many volcanic rock types including coherent and pyroclastic rocks; they span a wide range of compositions, occur in diverse environments, and form under a variety of pressure-temperature conditions. In subsurface volcanic environments (e.g., conduits and feeders), melts intersect the thermodynamically defined glass transition temperature to form glasses at elevated confining pressures and under differential stresses. We present a series of room temperature experiments designed to explore the fundamental mechanical and fragmentation behavior of natural (obsidian) and synthetic glasses (Pyrex™) under confining pressures of 0.1-100 MPa. In each experiment, glass cores are driven to brittle failure under compressive triaxial stress. Analysis of the load-displacement response curves is used to quantify the storage of energy in samples prior to failure, the (brittle) release of elastic energy at failure, and the residual energy stored in the post-failure material. We then establish a relationship between the energy density within the sample at failure and the grain-size distributions (D-values) of the experimental products. The relationship between D-values and energy density for compressive fragmentation is significantly different from relationships established by previous workers for decompressive fragmentation. Compressive fragmentation is found to have lower fragmentation efficiency than fragmentation through decompression (i.e., a smaller change in D-value with increasing energy density). We further show that the stress storage capacity of natural glasses can be enhanced (approaching synthetic glasses) through heat treatment.

  8. Obsidian hydration dating of volcanic events

    Science.gov (United States)

    Friedman, I.; Obradovich, J.

    1981-01-01

    Obsidian hydration dating of volcanic events had been compared with ages of the same events determined by the 14C and KAr methods at several localities. The localities, ranging in age from 1200 to over 1 million yr, include Newberry Craters, Oregon; Coso Hot Springs, California; Salton Sea, California; Yellowstone National Park, Wyoming; and Mineral Range, Utah. In most cases the agreement is quite good. A number of factors including volcanic glass composition and exposuretemperature history must be known in order to relate hydration thickness to age. The effect of composition can be determined from chemical analysis or the refractive index of the glass. Exposure-temperature history requires a number of considerations enumerated in this paper. ?? 1981.

  9. Analysis of glass fibre sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2014-01-01

    Glass fibre reinforced polymer composites are widely used for industrial and engineering applications which include construction, aerospace, automotive and wind energy industry. During the manufacturing glass fibres, they are surface-treated with an aqueous solution. This process and the treated...... surfaces are called sizing. The sizing influences the properties of the interface between fibres and a matrix, and subsequently affects mechanical properties of composites. In this work the sizing of commercially available glass fibres was analysed so as to study the composition and chemical structures....... Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  10. Marine mesocosm bacterial colonisation of volcanic ash

    Science.gov (United States)

    Witt, Verena; Cimarelli, Corrado; Ayris, Paul; Kueppers, Ulrich; Erpenbeck, Dirk; Dingwell, Donald; Woerheide, Gert

    2015-04-01

    Volcanic eruptions regularly eject large quantities of ash particles into the atmosphere, which can be deposited via fallout into oceanic environments. Such fallout has the potential to alter pH, light and nutrient availability at local scales. Shallow-water coral reef ecosystems - "rainforests of the sea" - are highly sensitive to disturbances, such as ocean acidification, sedimentation and eutrophication. Therefore, wind-delivered volcanic ash may lead to burial and mortality of such reefs. Coral reef ecosystem resilience may depend on pioneer bacterial colonisation of the ash layer, supporting subsequent establishment of the micro- and ultimately the macro-community. However, which bacteria are involved in pioneer colonisation remain unknown. We hypothesize that physico-chemical properties (i.e., morphology, mineralogy) of the ash may dictate bacterial colonisation. The effect of substrate properties on bacterial colonisation was tested by exposing five substrates: i) quartz sand ii) crystalline ash (Sakurajima, Japan) iii) volcanic glass iv) carbonate reef sand and v) calcite sand of similar grain size, in controlled marine coral reef aquaria under low light conditions for six months. Bacterial communities were screened every month by Automated Ribosomal Intergenic Spacer Analysis of the 16S-23S rRNA Internal Transcribed Spacer region. Multivariate statistics revealed discrete groupings of bacterial communities on substrates of volcanic origin (ash and glass) and reef origin (three sands). Analysis of Similarity supported significantly different communities associated with all substrates (p=0.0001), only quartz did not differ from both carbonate and calcite sands. The ash substrate exhibited the most diverse bacterial community with the most substrate-specific bacterial operational taxonomic units. Our findings suggest that bacterial diversity and community composition during colonisation of volcanic ash in a coral reef-like environment is controlled by the

  11. Sorption isotherms, thermodynamic properties and glass transition temperature of mucilage extracted from chia seeds (Salvia hispanica L.).

    Science.gov (United States)

    Velázquez-Gutiérrez, Sandra Karina; Figueira, Ana Cristina; Rodríguez-Huezo, María Eva; Román-Guerrero, Angélica; Carrillo-Navas, Hector; Pérez-Alonso, César

    2015-05-05

    Freeze-dried chia mucilage adsorption isotherms were determined at 25, 35 and 40°C and fitted with the Guggenheim-Anderson-de Boer model. The integral thermodynamic properties (enthalpy and entropy) were estimated with the Clausius-Clapeyron equation. Pore radius of the mucilage, calculated with the Kelvin equation, varied from 0.87 to 6.44 nm in the temperature range studied. The point of maximum stability (minimum integral entropy) ranged between 7.56 and 7.63kg H2O per 100 kg of dry solids (d.s.) (water activity of 0.34-0.53). Enthalpy-entropy compensation for the mucilage showed two isokinetic temperatures: (i) one occurring at low moisture contents (0-7.56 kg H2O per 100 kg d.s.), controlled by changes in water entropy; and (ii) another happening in the moisture interval of 7.56-24 kg H2O per 100 kg d.s. and was enthalpy driven. The glass transition temperature Tg of the mucilage fluctuated between 42.93 and 57.93°C.

  12. Microbially Mediated Glass Alteration in the Geological Record: Textural clues for Microbial Functions.

    Science.gov (United States)

    Staudigel, H.; Furnes, H.; McLoughlin, N.; Banerjee, N.

    2007-12-01

    Fe and Mn oxidizing microbes interact with their environment through the microbially mediated formation of Fe/Mn oxides and through the corrosion textures they may leave behind in the solids they colonize and from which they extract nutrients. Understanding the geo-biology of Fe and Mn oxidation may focus on the study of the microbes themselves, the mineral products, its biocorrosion features and the relationships between these types of observations. We have reviewed our own data on glass bio-corrosion and in particular the wider literature on microbial mineral tunneling to develop a two stage biocorrosion model for volcanic glass that offers feedback for our understanding of the mechanisms and the dynamics of microbial dissolution. Traces of microbially mediated dissolution of volcanic glass are commonly observed in volcanic glass found in submarine volcanoes on the seafloor, and in uplifted submarine volcanoes of almost any geological age back to the origin of life. Two main bioalteration textures care observed, granular and tubular. Based on a comparison of these features in particular with tunneling by ectomycorrhizal fungi, we propose two distinct types of biocorrosion that affects glass: (1) Granular alteration textures, made up of colonies of microbe-sized, near spherical mineral - filled cavities that form irregular clusters ranging to a tens of micron thick bands at the glas surfaces. These granular textures are interpreted as the result of microbial colonization. accompanied by dissolution of the glass in their contact surface, deposition of authigenic minerals and the formation of a biofilm, that eventually seals the glass from easy access by seawater for hydration, or from microbes accessing Fe (II) in the glass. (2) The most spectacular bioalteration feature, repesented by the formation of tubes cannot be easily formed by the former mechanism because near spherical, individual microbes are likely not to produce the directionality that is required to

  13. Glass sealing

    Energy Technology Data Exchange (ETDEWEB)

    Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

    1996-04-01

    Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

  14. Volcanic activity: a review for health professionals.

    Science.gov (United States)

    Newhall, C G; Fruchter, J S

    1986-03-01

    Volcanoes erupt magma (molten rock containing variable amounts of solid crystals, dissolved volatiles, and gas bubbles) along with pulverized pre-existing rock (ripped from the walls of the vent and conduit). The resulting volcanic rocks vary in their physical and chemical characteristics, e.g., degree of fragmentation, sizes and shapes of fragments, minerals present, ratio of crystals to glass, and major and trace elements composition. Variability in the properties of magma, and in the relative roles of magmatic volatiles and groundwater in driving an eruption, determine to a great extent the type of an eruption; variability in the type of an eruption in turn influences the physical characteristics and distribution of the eruption products. The principal volcanic hazards are: ash and larger fragments that rain down from an explosion cloud (airfall tephra and ballistic fragments); flows of hot ash, blocks, and gases down the slopes of a volcano (pyroclastic flows); "mudflows" (debris flows); lava flows; and concentrations of volcanic gases in topographic depressions. Progress in volcanology is bringing improved long- and short-range forecasts of volcanic activity, and thus more options for mitigation of hazards. Collaboration between health professionals and volcanologists helps to mitigate health hazards of volcanic activity.

  15. EXTRACT

    DEFF Research Database (Denmark)

    Pafilis, Evangelos; Buttigieg, Pier Luigi; Ferrell, Barbra

    2016-01-01

    The microbial and molecular ecology research communities have made substantial progress on developing standards for annotating samples with environment metadata. However, sample manual annotation is a highly labor intensive process and requires familiarity with the terminologies used. We have the...... and text-mining-assisted curation revealed that EXTRACT speeds up annotation by 15-25% and helps curators to detect terms that would otherwise have been missed.Database URL: https://extract.hcmr.gr/....

  16. Lunar Pyroclastic Eruptions: Basin Volcanism's Dying Gasps

    Science.gov (United States)

    Kramer, G. Y.; Nahm, A.; McGovern, P. J.; Kring, D. A.

    2011-12-01

    The relationship between mare volcanism and impact basins has long been recognized, although the degree of influence basin formation has on volcanism remains a point of contention. For example, did melting of magma sources result from thermal energy imparted by a basin-forming event? Did basin impacts initiate mantle overturn of the unstable LMO cumulate pile, causing dense ilmenite to sink and drag radioactive KREEPy material to provide the thermal energy to initiate melting of the mare sources? Did the dramatically altered stress states provide pathways ideally suited for magma ascent? The chemistry of sampled lunar volcanic glasses indicates that they experienced very little fractional crystallization during their ascent to the surface - they have pristine melt compositions. Volatile abundances, including recent measurements of OH [1,2] suggest that the mantle source of at least the OH-analyzed glasses have a water abundance of ~700 ppm - comparable to that of Earth's upper mantle. More recently, [3] showed that the abundance of OH and other volatiles measured in these glasses is positively correlated with trace element abundances, which is expected since water is incompatible in a magma. Volatile enrichment in a deep mantle source would lower the melting temperature and provide the thrust for magma ascent through 500 km of mantle and crust [4]. We are exploring the idea that such basin-related lunar pyroclastic volcanism may represent the last phase of basaltic volcanism in a given region. Remote sensing studies have shown volcanic glasses are fairly common, and often found along the perimeter of mare-filled basins [5]. Recent modeling of the stresses related to the basin-forming process [6,7] show that basin margins provide the ideal conduit for low-volume lunar pyroclastic volcanism (compared with the high output of mare volcanism). Schrödinger's basin floor is largely composed of a compositionally uniform impact breccia. The exceptions are two distinct and

  17. Volcanic ash and its enigma: A case study from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.

    -1 JOURNAL GEOLOGICAL SOCIETY OF INDIA Vol 60, August 2002, pp.127-130 Volcanic Ash and its Enigma: A Case Study from the Central Indian Ocean Basin J. N. PATTAN National Institute of Oceanography. Dona Paula. 403 004. Goa, India. Email: pattan... is reported. Keywords: Ash layer. Glass shards, Youngest Toba Tuff, Terrigenous influx, Indian Ocean. INTRODUCTION Marine ash layers provide information about cyclicity of volcanism. volcanic production rate and volume, eruption duration, geochemical...

  18. Particle analysis of volcanic ash with Electron Microscopy

    Science.gov (United States)

    Lieke, K. I.; Kristensen, T. B.; Koch, C. B.; Korsholm, U. S.; Sørensen, J. H.; Bilde, M.

    2012-04-01

    Since the airspace closure over Europe due to the Eyjafjalla eruption in 2010, volcanic ash has come more in the focus of atmospheric science. The airspace closure accompanying the Grímsvötn eruption in 2011 clearly indicates that there is still a great need to increase the scientific understanding of the properties and impacts of volcanic ash particles. Determination of particle characteristics, preferably in near real time, serves as an important input to transport models in operational use for decision support and guidance of authorities. We collected particles before and after the Grímsvötn volcanic ash arrived at Copenhagen, Denmark, between 23 May and 31 May 2011, as well as at a number of other locations. The analysis of meteorological conditions shows that the particle collection performed before arrival of the volcanic ash may serve as a good reference sample. We have thus been able to identify significant differences in aerosol chemical composition during a volcanic ash event over Copenhagen. These results are compared to volcanic ash particles collected on Iceland. We provide unique data about single-particle structure, chemical composition, size and morphology of volcanic ash particles. Single-particle analysis by SEM, and mineralogical studies by XRD and TEM prove that the particles are composed of glass of a characteristic composition and small, nm sized minerals attached to the large (up to tens of µm) glass fragments. The derived information about volcanic ash particles can be used by transport models, resulting in improved information to the authorities in case of new volcanic ash events over Scandinavia or Europe.

  19. Melting Behavior of Volcanic Ash relevant to Aviation Ash Hazard

    Science.gov (United States)

    Song, W.; Hess, K.; Lavallee, Y.; Cimarelli, C.; Dingwell, D. B.

    2013-12-01

    Volcanic ash is one of the major hazards caused by volcanic eruptions. In particular, the threat to aviation from airborne volcanic ash has been widely recognized and documented. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in-flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The primary cause of engine thrust loss is that the glass in volcanic ash particles is generated at temperatures far lower than the temperatures in the combustion chamber of a jet engine ( i.e. > 1600 oC) and when the molten volcanic ash particles leave this hottest section of the engine, the resolidified molten volcanic ash particles will be accumulated on the turbine nozzle guide vanes, which reduced the effective flow of air through the engine ultimately causing failure. Thus, it is essential to investigate the melting process and subsequent deposition behavior of volcanic ash under gas turbine conditions. Although few research studies that investigated the deposition behavior of volcanic ash at the high temperature are to be found in public domain, to the best our knowledge, no work addresses the formation of molten volcanic ash. In this work, volcanic ash produced by Santiaguito volcano in Guatemala in November 8, 2012 was selected for study because of their recent activity and potential hazard to aircraft safety. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the sintering and fusion phenomena as well as determine the volcanic ash melting behavior by using characteristic temperatures by means of hot stage microscope (HSM), different thermal analysis (DTA) and Thermal Gravimetric Analysis (TGA) to

  20. Complex Volcanism at Oppenheimer U Floor-Fractured Crater

    Science.gov (United States)

    Gaddis, L. R.; Bennett, K.; Horgan, B.; McBride, Marie; Stopar, J.; Lawrence, S.; Gustafson, J. O.; Giguere, T.

    2017-01-01

    Recent remote sensing studies have identified complex volcanism in the floor-fractured crater (FFC) Oppenheimer U, located in the northwest floor of Oppenheimer crater (35.2degS, 166.3degW, 208 km dia., Figure 1) within the "South Pole - Aitken basin" (SPA) region of the lunar far side. Up to 15 sites of pyroclastic volcanism have been identified in the floor of Oppenheimer crater. Studies of Moon Mineralogy Mapper data (M3, 0.4-3 microns, 86 bands, [5]) indicated that the pyroclastic deposits are comprised of mixtures of clinopyroxene and iron-rich glass, with the Oppenheimer U deposit showing variable composition within the FFC and having the most iron-rich volcanic glass thus far identified on the Moon. Here we examine the floor of Oppenheimer U in more detail and show evidence for possible multiple eruptive vents.

  1. A quantitative X-ray diffraction inventory of the tephra and volcanic glass inputs into the Holocene marine sediment archives off Iceland: A contribution to V.A.S.T.

    Science.gov (United States)

    Andrews, John T.; Kristjansdottir, Greta B.; Eberl, Dennis D.; Jennings, Anne E.

    2013-01-01

    This paper re-evaluates how well quantitative x-ray diffraction (qXRD) can be used as an exploratory method of the weight percentage (wt%) of volcaniclastic sediment, and to identify tephra events in marine cores. In the widely used RockJock v6 software programme, qXRD tephra and glass standards include the rhyodacite White River tephra (Alaska), a rhyolitic tephra (Hekla-4) and the basaltic Saksunarvatn tephra. Experiments of adding known wt% of tephra to felsic bedrock samples indicated that additions ≥10 wt% are accurately detected, but reliable estimates of lesser amounts are masked by amorphous material produced by milling. Volcaniclastic inputs range between 20 and 50 wt%. Primary tephra events are identified as peaks in residual qXRD glass wt% from fourth-order polynomial fits. In cores where tephras have been identified by shard counts in the > 150 µm fraction, there is a positive correlation (validation) with peaks in the wt% glass estimated by qXRD. Geochemistry of tephra shards confirms the presence of several Hekla-sourced tephras in cores B997-317PC1 and -319PC2 on the northern Iceland shelf. In core B997-338 (north-west Iceland), there are two rhyolitic tephras separated by ca. 100 cm with uncorrected radiocarbon dates on articulated shells of around 13 000 yr B.P. These tephras may be correlatives of the Borrobol and Penifiler tephras found in Scotland. The number of Holocene tephra events per 1000 yr was estimated from qXRD on 16 cores and showed a bimodal distribution with an increased number of events in both the late and early Holocene.

  2. Volcanic signals in oceans

    KAUST Repository

    Stenchikov, Georgiy L.

    2009-08-22

    Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

  3. Volcanic Rocks As Targets For Astrobiology Missions

    Science.gov (United States)

    Banerjee, N.

    2010-12-01

    Almost two decades of study highlight the importance of terrestrial subaqueous volcanic rocks as microbial habitats, particularly in glass produced by the quenching of basaltic lava upon contact with water. On Earth, microbes rapidly begin colonizing glassy surfaces along fractures and cracks exposed to water. Microbial colonization of basaltic glass leads to enhanced alteration through production of characteristic granular and/or tubular bioalteration textures. Infilling of formerly hollow alteration textures by minerals enable their preservation through geologic time. Basaltic rocks are a major component of the Martian crust and are widespread on other solar system bodies. A variety of lines of evidence strongly suggest the long-term existence of abundant liquid water on ancient Mars. Recent orbiter, lander and rover missions have found evidence for the presence of transient liquid water on Mars, perhaps persisting to the present day. Many other solar system bodies, notably Europa, Enceladus and other icy satellites, may contain (or have once hosted) subaqueous basaltic glasses. The record of terrestrial glass bioalteration has been interpreted to extend back ~3.5 billion years and is widespread in modern oceanic crust and its ancient metamorphic equivalents. The terrestrial record of glass bioalteration strongly suggests that glassy or formerly glassy basaltic rocks on extraterrestrial bodies that have interacted with liquid water are high-value targets for astrobiological exploration.

  4. Development of an inductively coupled plasma mass spectrometry method for quantification of extracted tungsten from glass prefilled syringes used as a primary packaging for pharmaceutical and therapeutic protein products.

    Science.gov (United States)

    Fujimori, Kiyoshi; Lee, Hans; Phillips, Joseph; Nashed-Samuel, Yasser

    2013-01-01

    Leachable tungsten is associated with protein aggregation and precipitation in glass prefilled syringes, and this may trigger immunogenicity concerns. Determining the level of leachable tungsten from glass prefilled syringes is critical for assuring quality of certain biopharmaceutical drug products. An inductively coupled plasma mass spectrometry (ICP/MS) quantification method was developed to determine elemental tungsten in syringe extracts. The syringe was extracted using 0.5% ammonium hydroxide (pH 11), heat (75 °C), and sonication. The resulting extraction solution was diluted 10 fold prior to ICP/MS analysis. Syringes from three syringe lots containing known low (average 28.0 ng), medium (average 189.4 ng), and high (average 631.9 ng) levels of tungsten were extracted three times each. All syringes with total tungsten greater than 14 ng had extraction efficiency greater than 90% with the first two extractions combined. The calibration curve range was 0.1-200 μg/L tungsten with iridium as the internal standard, and the correlation coefficient was ≥1.0000. The limit of detection at 0.05 μg/L tungsten and limit of quantification at 0.1 μg/L tungsten were determined as having a signal-to-noise ratio greater than 40 and 80 times compared with the blank, respectively. The ICP/MS method was selective for tungsten and iridium in the presence of other metals. Accuracies of spiked tungsten, at three different levels, in syringe extracts were >99% with precision relative standard deviation (RSD) (n = 5) of ≤1%. The matrix effect of the syringe extract media and carryover of tungsten and internal standard were negligible. Onboard stability of the syringe extracts over three days had a tungsten concentration RSD (n = 3) of ≤1%. Syringe extractions performed with 0.45-0.55% ammonium hydroxide had spike recoveries ≥99% and demonstrated extraction solution robustness. Quantified residual tungsten in syringes extract by ammonium hydroxide and analyzed by ICP

  5. Mechanical Properties of Man-Made Mineral glass fibres

    DEFF Research Database (Denmark)

    Lund, Majbritt Deichgræber; Yue, Yuanzheng

    In nature basaltic volcanic glass fibres are know from Hawaii as Pele's hair, formed by droplets of lava thrown into the air during volcanic eruption. The concept of glass fibre formation by an air stream dragging fibres from drops of melt is copied in industry to form basaltic glass wool fibres......; man-made mineral glass fibres. The basaltic melt is prevented from crystallizing due to the high cooling rate, forming the mineral glass wool fibres. Basaltic mineral wool fibres are of high interest in industry due to their good chemical durability and excellent heat and sound insulation properties...... of the information gained from the mechanical tests, fracture characteristics of individual glass fibres are imaged by scanning electron microscopy. The fracture surfaces showed to fall in three groups; 1) surfaces including fracture mirror, mist and hackle, 2) bend fracture surfaces and 3) surfaces including pores...

  6. Volcanic Rocks and Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanoes have contributed significantly to the formation of the surface of our planet. Volcanism produced the crust we live on and most of the air we breathe. The...

  7. Recycle Glass in Foam Glass Production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

  8. Cosmos & Glass

    DEFF Research Database (Denmark)

    Beim, Anne

    1996-01-01

    The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne.......The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne....

  9. Glass Glimpsed

    DEFF Research Database (Denmark)

    Lock, Charles

    2015-01-01

    Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology.......Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology....

  10. Volcanic hazards to airports

    Science.gov (United States)

    Guffanti, M.; Mayberry, G.C.; Casadevall, T.J.; Wunderman, R.

    2009-01-01

    Volcanic activity has caused significant hazards to numerous airports worldwide, with local to far-ranging effects on travelers and commerce. Analysis of a new compilation of incidents of airports impacted by volcanic activity from 1944 through 2006 reveals that, at a minimum, 101 airports in 28 countries were affected on 171 occasions by eruptions at 46 volcanoes. Since 1980, five airports per year on average have been affected by volcanic activity, which indicates that volcanic hazards to airports are not rare on a worldwide basis. The main hazard to airports is ashfall, with accumulations of only a few millimeters sufficient to force temporary closures of some airports. A substantial portion of incidents has been caused by ash in airspace in the vicinity of airports, without accumulation of ash on the ground. On a few occasions, airports have been impacted by hazards other than ash (pyroclastic flow, lava flow, gas emission, and phreatic explosion). Several airports have been affected repeatedly by volcanic hazards. Four airports have been affected the most often and likely will continue to be among the most vulnerable owing to continued nearby volcanic activity: Fontanarossa International Airport in Catania, Italy; Ted Stevens Anchorage International Airport in Alaska, USA; Mariscal Sucre International Airport in Quito, Ecuador; and Tokua Airport in Kokopo, Papua New Guinea. The USA has the most airports affected by volcanic activity (17) on the most occasions (33) and hosts the second highest number of volcanoes that have caused the disruptions (5, after Indonesia with 7). One-fifth of the affected airports are within 30 km of the source volcanoes, approximately half are located within 150 km of the source volcanoes, and about three-quarters are within 300 km; nearly one-fifth are located more than 500 km away from the source volcanoes. The volcanoes that have caused the most impacts are Soufriere Hills on the island of Montserrat in the British West Indies

  11. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  12. Size limits for rounding of volcanic ash particles heated by lightning.

    Science.gov (United States)

    Wadsworth, Fabian B; Vasseur, Jérémie; Llewellin, Edward W; Genareau, Kimberly; Cimarelli, Corrado; Dingwell, Donald B

    2017-03-01

    Volcanic ash particles can be remelted by the high temperatures induced in volcanic lightning discharges. The molten particles can round under surface tension then quench to produce glass spheres. Melting and rounding timescales for volcanic materials are strongly dependent on heating duration and peak temperature and are shorter for small particles than for large particles. Therefore, the size distribution of glass spheres recovered from ash deposits potentially record the short duration, high-temperature conditions of volcanic lightning discharges, which are hard to measure directly. We use a 1-D numerical solution to the heat equation to determine the timescales of heating and cooling of volcanic particles during and after rapid heating and compare these with the capillary timescale for rounding an angular particle. We define dimensionless parameters-capillary, Fourier, Stark, Biot, and Peclet numbers-to characterize the competition between heat transfer within the particle, heat transfer at the particle rim, and capillary motion, for particles of different sizes. We apply this framework to the lightning case and constrain a maximum size for ash particles susceptible to surface tension-driven rounding, as a function of lightning temperature and duration, and ash properties. The size limit agrees well with maximum sizes of glass spheres found in volcanic ash that has been subjected to lightning or experimental discharges, demonstrating that the approach that we develop can be used to obtain a first-order estimate of lightning conditions in volcanic plumes.

  13. Precambrian Lunar Volcanic Protolife

    Directory of Open Access Journals (Sweden)

    Jack Green

    2009-06-01

    Full Text Available Five representative terrestrial analogs of lunar craters are detailed relevant to Precambrian fumarolic activity. Fumarolic fluids contain the ingredients for protolife. Energy sources to derive formaldehyde, amino acids and related compounds could be by flow charging, charge separation and volcanic shock. With no photodecomposition in shadow, most fumarolic fluids at 40 K would persist over geologically long time periods. Relatively abundant tungsten would permit creation of critical enzymes, Fischer-Tropsch reactions could form polycyclic aromatic hydrocarbons and soluble volcanic polyphosphates would enable assembly of nucleic acids. Fumarolic stimuli factors are described. Orbital and lander sensors specific to protolife exploration including combined Raman/laser-induced breakdown spectrocsopy are evaluated.

  14. Glass microsphere lubrication

    Science.gov (United States)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  15. Halogen behaviours during andesitic magma degassing: from magma chamber to volcanic plume

    Science.gov (United States)

    Balcone-Boissard, H.; Villemant, B.; Boudon, G.; Michel, A.

    2009-04-01

    Halogen (F, Cl, Br and I) behaviours during degassing of H2O-rich silicic magmas are investigated using volatile content analysis in glass (matrix glass and melt inclusions) of volcanic clasts (pumice and lava-dome fragments) in a series of plinian, vulcanian and lava dome-forming eruptions. Examples are taken from andesitic systems in subduction zones: Montagne Pelée and Soufrière Hills of Montserrat (Lesser Antilles) and Santa Maria-Santiaguito (Guatemala). Halogens behaviour during shallow degassing primarily depends on their incompatible character in melts and on H2O solubility. But variations in pre-eruptive conditions, degassing kinetics and syn-eruptive melt crystallisation, induce large variations in halogen extraction efficiency during H2O degassing, up to prevent halogen loss. In all studied systems, Cl, Br and I are not fractionated neither by differentiation nor by degassing processes: thus Cl/Br/I ratios remain well preserved in melts from reservoirs to eruption. These ratios measured in erupted clasts are characteristic of pre-eruptive magma compositions and may be used to trace deep magmatic processes. Moreover, during plinian eruptions, Cl, Br and I are extracted by H2O degassing but less efficiently than predicted by available experimental fluid-melt partition coefficients, by a factor as high as 5. F behaves as an incompatible element and, contrary to other halogens, is never significantly extracted by degassing. Degassing during lava dome-forming eruptions of andesitic magmas occurs mainly at equilibrium and is more efficient at extracting halogens and H2O than explosive degassing. The mobility of H2O and halogens depends on their speciation in both silicate melts and exsolved fluids which strongly varies with pressure. We suggest that the rapid pressure decrease during highly explosive eruptions prevents complete volatile speciation at equilibrium and consequently strongly limits halogen degassing.

  16. Lung problems and volcanic smog

    Science.gov (United States)

    ... releases gases into the atmosphere. Volcanic smog can irritate the lungs and make existing lung problems worse. ... deep into the lungs. Breathing in volcanic smog irritates the lungs and mucus membranes. It can affect ...

  17. Volcanism and Oil & Gas In Northeast China

    Institute of Scientific and Technical Information of China (English)

    Shan Xuanlong

    2000-01-01

    Based on study on the relation with volcanic rock and oil & gas in Songliao Basin and Liaohe Basin in northeast China, author proposes that material from deep by volcanism enrichs the resources in basins, that heat by volcanism promotes organic matter transforming to oil and gas, that volcanic reservoir is fracture, vesicular, solution pore, intercrystal pore.Lava facies and pyroclastic facies are favourable reservoir. Mesozoic volcanic reservoir is majority of intermediate, acid rock,but Cenozoic volcanic reservoir is majority of basalt. Types of oil and gas pool relating to volcanic rock include volcanic fracture pool, volcanic unconformity pool, volcanic rock - screened pool, volcanic darpe structural pool.

  18. Modeling volcanic ash dispersal

    CERN Document Server

    CERN. Geneva

    2010-01-01

    The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard...

  19. Properties of volcanic soils in cold climate conditions

    Science.gov (United States)

    Kuznetsova, Elena

    2017-04-01

    Layers of volcanic ash and the Andosol soils derived from them may play an important role in preserving snow and ice as well as developing permafrost conditions in the immediate vicinity of volcanoes of high elevation or those situated at high latitudes, and land areas, often distant from volcanic activity that are either prone to permafrost or covered by snow and ice, but are affected by the deposition of subaerial ash. The special properties of volcanic ash that are responsible are critically reviewed particularly in relation to recent research in Kamchatka in the Far East of Russia. Of particular importance are the thermal properties and the unfrozen water contents of ash layers and the rate at which the weathering of volcanic glass takes place. Volcanic glass is the most easily weathered component of volcanic ejecta (Shoji et al., 1993; Kimble et al., 2000). There are many specific environmental conditions, including paleoclimate and present-day climate, the composition of volcanic tephra and glaciation history, which cause the differences in weathering and development of volcanic ash soils (Zehetner et al., 2003). The preservation of in situ, unweathered, and unaltered surficial ash-fall deposits in the cold regions has important implications for paleoclimate and glacial history. Ash-fall deposits, which trap and preserve the soils, sediments, and landforms on which they fall, can be used to resolve local climate conditions (temperature and moisture) at the ash site during ash-fall deposition. The preservation of detailed sedimentary features (e.g. bedding in the ash, sharpness of stratigraphic contacts) can tell us about their post-depositional history, whether they have been redeposited by wind or water, or overridden by glaciers (Marchant et al., 1996). Weathering of volcanic glass results in the development of amorphous clay minerals (e.g. allophane, opal, palagonite) but this takes place much slower in cold than under warmer climate conditions. Only few

  20. THE MEANING OF VOLCANIC ASH CHARACTERISTICS FOUND IN THE ARCHAEOLOGICAL POTTERY OF CHICHEN ITZA, YUCATAN, MEXICO

    OpenAIRE

    Chung, Heajoo; Song, Youngsun

    2014-01-01

    The Yucatan peninsula is a limestone based karst region. However, most of the pottery fragments from the Mayan Postclassic period of Chichen Itza, Yucatan, Mexico, contain volcanic materials as temper. Petrographic thin section analysis of pottery from Chichen Itza and related Yucatan archaeological sites shows that volcanic materials in the paste composition have two distinguishing characteristics. The glass shards and pumice frag-ments found in the pottery are fresh in form, mineralogically...

  1. Carbothermal reduction process of silica formed from shirasu volcanic ash using solar furnace

    OpenAIRE

    Hatakeyama Keisuke; Sato Keigo; Nishioka Kensuke

    2016-01-01

    Metallurgical grade silicon was formed using Shirasu volcanic ash as starting material with solar furnace. The solar furnace was composed of two parts: Fresnel lens and reacting furnace. The reacting furnace was composed of a cylindrical vacuum chamber and quartz glass plate functioning to guide the concentrated sunlight into the furnace, and was placed at the focal point of the Fresnel lens. The sample was made from a mixture of silica formed from Shirasu volcanic ash and carbon, and placed ...

  2. International Database of Volcanic Ash Impacts

    Science.gov (United States)

    Wallace, K.; Cameron, C.; Wilson, T. M.; Jenkins, S.; Brown, S.; Leonard, G.; Deligne, N.; Stewart, C.

    2015-12-01

    Volcanic ash creates extensive impacts to people and property, yet we lack a global ash impacts catalog to organize, distribute, and archive this important information. Critical impact information is often stored in ephemeral news articles or other isolated resources, which cannot be queried or located easily. A global ash impacts database would improve 1) warning messages, 2) public and lifeline emergency preparation, and 3) eruption response and recovery. Ashfall can have varying consequences, such as disabling critical lifeline infrastructure (e.g. electrical generation and transmission, water supplies, telecommunications, aircraft and airports) or merely creating limited and expensive inconvenience to local communities. Impacts to the aviation sector can be a far-reaching global issue. The international volcanic ash impacts community formed a committee to develop a database to catalog the impacts of volcanic ash. We identify three user populations for this database: 1) research teams, who would use the database to assist in systematic collection, recording, and storage of ash impact data, and to prioritize impact assessment trips and lab experiments 2) volcanic risk assessment scientists who rely on impact data for assessments (especially vulnerability/fragility assessments); a complete dataset would have utility for global, regional, national and local scale risk assessments, and 3) citizen science volcanic hazard reporting. Publication of an international ash impacts database will encourage standardization and development of best practices for collecting and reporting impact information. Data entered will be highly categorized, searchable, and open source. Systematic cataloging of impact data will allow users to query the data and extract valuable information to aid in the development of improved emergency preparedness, response and recovery measures.

  3. Exploring Hawaiian Volcanism

    Science.gov (United States)

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken

    2013-02-01

    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai`i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO's founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists' understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  4. Exploring Hawaiian volcanism

    Science.gov (United States)

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken

    2013-01-01

    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai‘i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO’s founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists’ understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  5. The Relative Rates of Secondary Hydration in Basalt and Rhyolite, and the use of δD as a Paleoclimate Indicator: Implications for Paleoenvironmental and Volcanic Degassing Studies

    Science.gov (United States)

    Seligman, A. N.; Bindeman, I. N.

    2014-12-01

    The δD-H2O correlation is important for volcanic degassing and secondary hydration trends. We utilize the caibration of the TC/EA - MAT 253 continuous flow system, which permits us to analyze wt.% H2O and its δD extracted from 1-8 mg of glass with as little as 0.1 wt% H2O. Tephra that has been secondarily hydrated with meteoric water is widely used as a paleoenvironmental tool, but the rate of secondary hydration, the relative amounts of primary magmatic (degassed) and secondary meteoric water, and the retention of primary and secondary δD values are not well understood. To quantify these processes, we use a natural experiment involving dated Holocene tepha in Kamchatka and Oregon. Our research illustrates the drastic difference in hydration rates between silicic (hydrated after ~1.5 ka) and mafic tephra, which is not hydrated in the Holocene (similar to results for submarine volcanic glasses), and andesitic tephra with intermediate degrees of hydration. The 0.05-7.3 ka basaltic scoria from Klyuchevskoy volcano retains ≤0.45 wt.% primary magmatic H2O, with δD values from -99 to -121 ‰. Four other 0.05-7.6 ka basaltic tephra units from Kamchatka with 65 wt.% have higher (1.5 -3.4) wt.% H2O and δD values between -115 - -160 ‰. We interpret the lower δD values and higher water contents (opposite of the magmatic degassing trend) to be a characteristic of secondary hydration in regions of higher latitude such as Kamchatka and Oregon. We are also investigating 7.7 ka Mt. Mazama tephra in Oregon that are known to be fully hydrated and cover nearly 5000 km2 northeast of Crater Lake and range in elevation from ~1.3-1.9 km to understand the δD and δ18O details of the hydrated water's correspondence with local Holocene meteoric waters. In the future, we plan to use a combination of δD in mid-high latitude precipitation to delineate δD-H2O hydration trends to better understand the distinction between primary magmatic and secondary meteoric water in volcanic

  6. Subdiffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi

    2016-01-01

    A comparative study is performed on volcanic seismicities at Mt.Eyjafjallajokull in Iceland and Mt. Etna in Sicily, Italy, from the viewpoint of science of complex systems, and the discovery of remarkable similarities between them regarding their exotic spatio-temporal properties is reported. In both of the volcanic seismicities as point processes, the jump probability distributions of earthquakes are found to obey the exponential law, whereas the waiting-time distributions follow the power law. In particular, a careful analysis is made about the finite size effects on the waiting-time distributions, and accordingly, the previously reported results for Mt. Etna [S. Abe and N. Suzuki, EPL 110, 59001 (2015)] are reinterpreted. It is shown that spreads of the volcanic earthquakes are subdiffusive at both of the volcanoes. The aging phenomenon is observed in the "event-time-averaged" mean-squared displacements of the hypocenters. A comment is also made on presence/absence of long term memories in the context of t...

  7. Determination of Reactive Surface Area of Melt Glass

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier,W.L.; Roberts, S.; Smith, D.K.; Hulsey, S.; Newton,L.; Sawvel, A.; Bruton, C.; Papelis, C.; Um, W.; Russell, C. E.; Chapman,J.

    2000-10-01

    A comprehensive investigation of natural and manmade silicate glasses, and nuclear melt glass was undertaken in order to derive an estimate of glass reactive surface area. Reactive surface area is needed to model release rates of radionuclides from nuclear melt glass in the subsurface. Because of the limited availability of nuclear melt glasses, natural volcanic glass samples were collected which had similar textures and compositions as those of melt glass. A flow-through reactor was used to measure the reactive surface area of the analog glasses in the presence of simplified NTS site ground waters. A measure of the physical surface area of these glasses was obtained using the BET gas-adsorption method. The studies on analog glasses were supplemented by measurement of the surface areas of pieces of actual melt glass using the BET method. The variability of the results reflect the sample preparation and measurement techniques used, as well as textural heterogeneity inherent to these samples. Based on measurements of analog and actual samples, it is recommended that the hydraulic source term calculations employ a range of 0.001 to 0.01 m{sup 2}/g for the reactive surface area of nuclear melt glass.

  8. Volcanism on Mars. Chapter 41

    Science.gov (United States)

    Zimbelman, J. R.; Garry, W. B.; Bleacher, J. E.; Crown, D. A.

    2015-01-01

    Spacecraft exploration has revealed abundant evidence that Mars possesses some of the most dramatic volcanic landforms found anywhere within the solar system. How did a planet half the size of Earth produce volcanoes like Olympus Mons, which is several times the size of the largest volcanoes on Earth? This question is an example of the kinds of issues currently being investigated as part of the space-age scientific endeavor called "comparative planetology." This chapter summarizes the basic information currently known about volcanism on Mars. The volcanoes on Mars appear to be broadly similar in overall morphology (although, often quite different in scale) to volcanic features on Earth, which suggests that Martian eruptive processes are not significantly different from the volcanic styles and processes on Earth. Martian volcanoes are found on terrains of different age, and Martian volcanic rocks are estimated to comprise more than 50% of the Martian surface. This is in contrast to volcanism on smaller bodies such as Earth's Moon, where volcanic activity was mainly confined to the first half of lunar history (see "Volcanism on the Moon"). Comparative planetology supports the concept that volcanism is the primary mechanism for a planetary body to get rid of its internal heat; smaller bodies tend to lose their internal heat more rapidly than larger bodies (although, Jupiter's moon Io appears to contradict this trend; Io's intense volcanic activity is powered by unique gravitational tidal forces within the Jovian system; see "Volcanism on Io"), so that volcanic activity on Mars would be expected to differ considerably from that found on Earth and the Moon.

  9. Triple oxygen and sulfur isotope analyses of sulfate extracted from voluminous volcanic ashes in the Oligocene John Day Formation: insight into dry climate conditions and ozone contribution to supereruptions

    Science.gov (United States)

    Workman, J.; Bindeman, I. N.; Martin, E.; Retallack, G.; Palandri, J. L.; Weldon, N.

    2014-12-01

    Large volume pyroclastic silicic eruptions emit hundreds of megatons of SO2 into the troposphere and stratosphere that is oxidized into sulfuric acid (H2SO4) by a variety of reactions with mass independent oxygen signatures (MIF), Δ17O>0. Sulfuric acid is then preserved as gypsum in parental volcanic deposits. Diagenic effects are mass dependent and can dilute, but otherwise do not affect MIF ratios. Pleistocene Yellowstone and Bishop tuffs and modern volcanic eruptions preserved under arid climate conditions in North American playa lakes, preserve small amounts of volcanic sulfate as gypsum. This gypsum's Δ17O>0, in combination with isotopic variations of δ18O, δ33S and δ34S is distinct from sedimentary sulfate and reveals its original MIF sulfate isotopic signal and the effect of super eruptions on the atmosphere, and ozone consumption in particular. We use linear algebraic equations to resolve volcanic versus sedimentary (MIF=0) sources. We have found that many large volume ignimbrites have very high initial Δ17O in volcanic sulfate that can only be acquired from reaction with stratospheric ozone. We here investigate nine thick (>2 m) ash beds ranging in age from ~33-23 Ma in the John Day Formation of central Oregon, including massive 28.6 Ma Picture Gorge tuff of newly identified Crooked River supercaldera. The 28.6 Ma Picture Gorge tuff (PGT) has the highest measured Δ17O of 3.5‰, and other tuffs (Tin Roof, Biotite, Deep Creek) have +1.3 to 3.4‰ Δ17O excesses. Sulfate from modern smaller tropospheric eruptions studied for comparison have a resolvable 0.4‰ range consistent with liquid-phase based H2O2 oxidation. The PGT is coeval with the ignimbrite flare-up in western N. America, the 28-29 Ma eruption of the 5000 km3 Fish Canyon tuff and the 28 Ma Never Summer Field eruption in Nebraska-Colorado that have the highest measured Δ17O of 6‰ (Bao et al. 2003). We speculate on the climatic/atmospheric effects of these multiple ~28 Ma supereruptions

  10. Volcanic Ash Nephelometer Probe Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes may enable unprecedented observations of...

  11. Volcanic Eruptions and Climate

    Science.gov (United States)

    Robock, A.

    2012-12-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  12. System of Volcanic activity

    Directory of Open Access Journals (Sweden)

    P. HÉDERVARI

    1972-06-01

    Full Text Available A comparison is made among the systems of B. G.
    Escher (3, of R. W. van Bemmelen (1 and that of the author (4. In this
    connection, on the basis of Esclier's classification, the terms of "constructiv
    e " and "destructive" eruptions are introduced into the author's system and
    at the same time Escher's concept on the possible relation between the depth
    of magma-chamber and the measure of the gas-pressure is discussed briefly.
    Three complementary remarks to the first paper (4 011 the subject of system
    of volcanic activity are added.

  13. Halide laser glasses

    Energy Technology Data Exchange (ETDEWEB)

    Weber, M.J.

    1982-01-14

    Energy storage and energy extraction are of prime importance for efficient laser action and are affected by the line strengths and linewidths of optical transitions, excited-state lifetimes, nonradiative decay processes, spectroscopic inhomogeneities, nonlinear refractive index, and damage threshold. These properties are all host dependent. To illustrate this, the spectroscopic properties of Nd/sup 3 +/ have been measured in numerous oxide, oxyhalide, and halide glasses. A table summarizes the reported ranges of stimulated emission cross sections, peak wavelengths, linewidths, and radiative lifetimes associated with the /sup 4/F/sub 3/2/ ..-->.. /sup 4/I/sub 11/2/ lasing transition.

  14. Volcanic gas composition, metal dispersion and deposition during explosive volcanic eruptions on the Moon

    Science.gov (United States)

    Renggli, C. J.; King, P. L.; Henley, R. W.; Norman, M. D.

    2017-06-01

    The transport of metals in volcanic gases on the Moon differs greatly from their transport on the Earth because metal speciation depends largely on gas composition, temperature, pressure and oxidation state. We present a new thermochemical model for the major and trace element composition of lunar volcanic gas during pyroclastic eruptions of picritic magmas calculated at 200-1500 °C and over 10-9-103 bar. Using published volatile component concentrations in picritic lunar glasses, we have calculated the speciation of major elements (H, O, C, Cl, S and F) in the coexisting volcanic gas as the eruption proceeds. The most abundant gases are CO, H2, H2S, COS and S2, with a transition from predominantly triatomic gases to diatomic gases with increasing temperatures and decreasing pressures. Hydrogen occurs as H2, H2S, H2S2, HCl, and HF, with H2 making up 0.5-0.8 mol fractions of the total H. Water (H2O) concentrations are at trace levels, which implies that H-species other than H2O need to be considered in lunar melts and estimates of the bulk lunar composition. The Cl and S contents of the gas control metal chloride gas species, and sulfide gas and precipitated solid species. We calculate the speciation of trace metals (Zn, Ga, Cu, Pb, Ni, Fe) in the gas phase, and also the pressure and temperature conditions at which solids form from the gas. During initial stages of the eruption, elemental gases are the dominant metal species. As the gas loses heat, chloride and sulfide species become more abundant. Our chemical speciation model is applied to a lunar pyroclastic eruption model with isentropic gas decompression. The relative abundances of the deposited metal-bearing solids with distance from the vent are predicted for slow cooling rates (<5 °C/s). Close to a volcanic vent we predict native metals are deposited, whereas metal sulfides dominate with increasing distance from the vent. Finally, the lunar gas speciation model is compared with the speciation of a H2O-, CO

  15. Volcan Reventador's Unusual Umbrella

    Science.gov (United States)

    Chakraborty, P.; Gioia, G.; Kieffer, S. W.

    2005-12-01

    In the past two decades, field observations of the deposits of volcanoes have been supplemented by systemmatic, and sometimes, opportunistic photographic documentation. Two photographs of the umbrella of the December 3, 2002 eruption of Volcan Reventador, Ecuador, reveal a prominently scalloped umbrella that is unlike any umbrella previously documented on a volcanic column. The material in the umbrella was being swept off a descending pyroclastic flow, and was, therefore, a co-ignimbrite cloud. We propose that the scallops are the result of a turbulent Rayleigh-Taylor (RT) instability with no precedents in volcanology. We ascribe the rare loss of buoyancy that drives this instability to the fact that the Reventador column fed on a cool co-ignimbrite cloud. On the basis of the observed wavelength of the scallops, we estimate a value for the eddy viscosity of the umbrella of 4000 ~m2/s. This value is consistent with a previously obtained lower bound (200 ~m2/s, K. Wohletz, priv. comm., 2005). We do not know the fate of the material in the umbrella subsequent to the photos. The analysis suggests that the umbrella was negatively buoyant. Field work on the co-ignimbrite deposits might reveal whether or not the material reimpacted, and if so, where and whether or not this material was involved in the hazardous flows that affected the main oil pipeline across Ecuador.

  16. Uranium series, volcanic rocks

    Science.gov (United States)

    Vazquez, Jorge A.

    2014-01-01

    Application of U-series dating to volcanic rocks provides unique and valuable information about the absolute timing of crystallization and differentiation of magmas prior to eruption. The 238U–230Th and 230Th-226Ra methods are the most commonly employed for dating the crystallization of mafic to silicic magmas that erupt at volcanoes. Dates derived from the U–Th and Ra–Th methods reflect crystallization because diffusion of these elements at magmatic temperatures is sluggish (Cherniak 2010) and diffusive re-equilibration is insignificant over the timescales (less than or equal to 10^5 years) typically associated with pre-eruptive storage of nearly all magma compositions (Cooper and Reid 2008). Other dating methods based on elements that diffuse rapidly at magmatic temperatures, such as the 40Ar/39Ar and (U–Th)/He methods, yield dates for the cooling of magma at the time of eruption. Disequilibrium of some short-lived daughters of the uranium series such as 210Po may be fractionated by saturation of a volatile phase and can be employed to date magmatic gas loss that is synchronous with volcanic eruption (e.g., Rubin et al. 1994).

  17. Volcanic Eruptions and Climate

    Science.gov (United States)

    LeGrande, Allegra N.; Anchukaitis, Kevin J.

    2015-01-01

    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  18. Preliminary characterization of glass fiber sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2013-01-01

    Glass fiber surfaces are treated with sizing during manufacturing. Sizing consists of several components, including a film former and a silane coupling agent that is important for adhesion between glass fibers and a matrix. Although the sizing highly affects the composite interface and thus...... the strength of the composites, little is known about the structure and chemistry of the sizing. A part of sizing was extracted by soxhlet extraction. The fibers were subsequently burned and some fibers were merely burned for analysis of glass fiber and sizing. The results showed that the analyzed fibers had...

  19. Mare glasses from Apollo 17 - Constraints on the moon's bulk composition

    Science.gov (United States)

    Delano, J. W.; Lindsley, D. H.

    1983-01-01

    Two previously unreported varieties of mare volcanic glass have been discovered in Apollo 17 samples. Twenty-three chemical types of volcanic glass have now been analyzed from the six Apollo landing sites. These volcanic glasses, which may be samples of primary magmas derived from the differentiated lunar mantle, define two linear arrays that seem to reflect regional, if not global, regularities among the source regions of these melts. Additional systematics among these glasses have been used to estimate the bulk composition of the moon. The results suggest that the refractory lithophile elements are present at abundances of 1.7 x chondrites. The silicate portion of the moon appears to have a major-element composition similar to a volatile (Si, Na, K)-depleted, earth's upper mantle. The theory involving an earth-fission origin of the moon can be tested further through trace element analyses on the volcanic glasses, and through determination of the N/Ar-36 ratio and noble gas isotopes from primordial lunar gas trapped within vesicles associated with mare volcanic glass.

  20. Characterization of fine volcanic ash from explosive eruption from Sakurajima volcano, South Japan

    Science.gov (United States)

    Nanayama, F.; Furukawa, R.; Ishizuka, Y.; Yamamoto, T.; Geshi, N.; Oishi, M.

    2013-12-01

    distributions of volcanic ash from Sakurajima volcano have basically characteristics of unimodal and gaussian. Mode of distributions are 150 - 200 micron at 5 km and 70-80 micron at 20 km respectively from the Showa crater. Mode and deviation of the grain size distribution are function of distance from the source. Fine volcanic ash less than 1 micron in diameter is few and exists in every samples. Component of volcanic ash samples are dark-colored dense glass shard (ca. 50%), light-colored dense glass shard (10%), variously colored and vesiculated glass shard (10%), free crystal (20%), lithic fragment (10%), and altered fragment (less than 5%) which are mostly having similar ratio in every location suggesting single source process of the eruption. We also found fine volcanic ash samples less than 10 micron are frequently aggregated. The present study includes the result of "Research and Development of Margin Assessment Methodology of Decay Heat Removal Function against External Hazards" entrusted to Japan Atomic Energy Agency by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT).

  1. Comparative Analysis of Volcanic Inflation—Deflation Cycles

    Science.gov (United States)

    Walwer, D.; Ghil, M.; Calais, E.

    2016-12-01

    GPS geodetic data together with INSAR images are often used to formulate kinematic models of the sources of volcanic deformations. The increasing amount of data now available allows one to produce time series that are several years long and thus capture continuously the history of volcanic deformations, in particular their nonlinear behavior. This information is highly valuable in helping understand the dynamics of volcanic systems.Nonlinear deformation signals are, however, difficult to extract from the background noise inherent in the GPS time series. It is also arduous to unravel the signal of interest from other nonlinear signals, such as the seasonal oscillations associated with mass variations in the atmosphere, the ocean, and the hydrological reservoirs. Here we use Multichannel Singular Spectrum Analysis (M-SSA) — an advanced, data-adaptive method for time series analysis that exploits simultaneously the temporal and spatial correlations of geophysical fields — to extract such deformation signals.We apply M-SSA to GPS data sets from four volcanoes: Akutan, Alaska; Okmok, Alaska; Westdahl, Alaska; and Piton de la Fournaise, La Reunion. Our analyses show that all four volcanoes share similar features in their deformation history, suggesting similarities in the dynamics that generate the inflation-deflation cycles. In particular, all four volcanic systems exhibit sawtooth-shaped oscillations with slow inflations followed by slower deflations, with time scales that vary from 6 months to 4 years. This relation of dynamical similarity is further highlighted by the phase portrait reconstruction of the four systems in the plane of deformation vs. rate-of-deformation, as obtained from the deformation signals extracted from the GPS time series using M-SSA.The inflating phase of these oscillations is followed by eruptions at Okmok volcano and at Piton de la Fournaise. These analysis results suggest that these volcanic inflation—deflation cycles are associated

  2. Comprehensive analytical methodology to determine hydrocarbons in marine waters using extraction disks coupled to glass fiber filters and compound-specific isotope analyses.

    Science.gov (United States)

    Ternon, Eva; Tolosa, Imma

    2015-07-24

    Solid-phase extraction of both aliphatic (AHs) and aromatic polycyclic hydrocarbons (PAHs) from seawater samples was evaluated using a GFF filter stacked upon an octadecyl bonded silica (C18) disk. Stable-isotope measurements were developed on hydrocarbons extracted from both GFF and C18-disks in order to characterize the source of hydrocarbons. A clear partition of hydrocarbon compounds between the dissolved and the particulate phase was highlighted. PAHs showed a higher affinity with the dissolved phase (recoveries efficiency of 48-71%) whereas AHs presented strong affinity with the particulate phase (up to 76% of extraction efficiency). Medium volumes of seawater samples were tested and no breakthrough was observed for a 5L sample. Isotopic fractionation was investigated within all analytical steps but none was evidenced. This method has been applied to harbor seawater samples and very low AH and PAH concentrations were achieved. Due to the low concentration levels of hydrocarbons in the samples, the source of hydrocarbons was determined by molecular indices rather than isotopic measurements and a pyrolytic origin was evidenced. The aliphatic profile also revealed the presence of long-chain linear alkylbenzenes (LABs). The methodology presented here would better fit to polluted coastal environments affected by recent oil spills.

  3. Volcanic studies at Katmai

    Energy Technology Data Exchange (ETDEWEB)

    1989-12-31

    The Continental Scientific Drilling Program (CSDP) is a national effort supported by the Department of Energy, the US Geological Survey, and the National Science Foundation. One of the projects proposed for the CSDP consists of drilling a series of holes in Katmai National Park in Alaska to give a third dimension to the model of the 1912 eruption of Novarupta, and to investigate the processes of explosive volcanism and hydrothermal transport of metals (Eichelberger et al., 1988). The proposal for research drilling at Katmai states that ``the size, youth, elevated temperature, and simplicity of the Novarupta vent make it a truly unique scientific target.`` The National Park Service (NPS), which has jurisdiction, is sympathetic to aims of the study. However, NPS wishes to know whether Katmai is indeed uniquely suited to the research, and has asked the Interagency Coordinating Group to support an independent assessment of this claim. NPS suggested the National Academy of Sciences as an appropriate organization to conduct the assessment. In response, the National Research Council -- the working arm of the Academy -- established, under the aegis of its US Geodynamics Committee, a panel whose specific charge states: ``The proposed investigation at Katmai has been extensively reviewed for scientific merit by the three sponsoring and participating agencies. Thus, the scientific merit of the proposed drilling at Katmai is not at issue. The panel will review the proposal for scientific drilling at Katmai and prepare a short report addressing the specific question of the degree to which it is essential that the drilling be conducted at Katmai as opposed to volcanic areas elsewhere in the world.``

  4. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina

    The extensive Quaternary volcanism in the Payenia volcanic province, Mendoza, Argentina, is investigated in this study by major and trace element analyses, Sr, Nd, Hf and Pb-isotopic analyses and Zr-Hf isotope dilution data on samples from almost the entire province. The samples are mainly...... in basalts from all the studied volcanic fields in Payenia is signs of lower crustal contamination indicating assimilation of, in some cases, large amounts of trace element depleted, mafic, plagioclase-bearing rocks. The northern Payenia is dominated by backarc basalts erupted between late Pliocene to late...

  5. The Source of Volcanic Ash in Late Classic Maya Pottery at El Pilar, Belize

    Science.gov (United States)

    Catlin, B. L.; Ford, A.; Spera, F. J.

    2007-12-01

    The presence of volcanic ash used as temper in Late Classic Maya pottery (AD 600-900) at El Pilar has been long known although the volcano(s) contributing ash have not been identified. We use geochemical fingerprinting, comparing compositions of glass shards in potsherds with volcanic sources to identify the source(s). El Pilar is located in the Maya carbonate lowlands distant from volcanic sources. It is unlikely Maya transported ash from distant sites: ash volumes are too large, the terrain too rugged, and no draft animals were available. Ash layer mining is unlikely because mine sites have not been found despite intensive surveys. Nearest volcanic sources to El Pilar, Belize and Guatemala, are roughly 450 km to the south and east. The ash found in potsherds has a cuspate morphology. This suggests ash was collected during, or shortly after, an ash airfall event following eruption. Analyses of n=333 ash shards from 20 ceramic (pottery) sherds was conducted by electron microprobe for major elements, and LA-ICPMS for trace elements and Pb isotopes. These analyses can be compared to volcanic materials from candidate volcanoes in the region. The 1982 El Chichon eruption caused airfall deposition (pot firing on glass compositional changes, experiments were conducted in which high silica volcanic glass was fired with clay according to heating schedules used by Maya potters. Two important changes are that Na is rapidly lost preferentially to K and that the Si/Ca ratio decreases due to Ca diffusion from matrix into glass during firing. One expects that ratios of the refractory trace elements such as La/Yb and Zr/Hf are less susceptible to modification. Further experiments of trace element mobility during firing are underway.

  6. Source identification of volcanic ashes by geochemical analysis of well preserved lacustrine tephras in Nahuel Huapi National Park

    Energy Technology Data Exchange (ETDEWEB)

    Daga, Romina [Laboratorio de Analisis por Activacion Neutronica, Centro Atomico Bariloche, 8400 Bariloche (Argentina)], E-mail: romina@cab.cnea.gov.ar; Ribeiro Guevara, Sergio [Laboratorio de Analisis por Activacion Neutronica, Centro Atomico Bariloche, 8400 Bariloche (Argentina); Sanchez, Maria Lidia [Universidad Nacional de Rio Cuarto, 5800 Rio Cuarto (Argentina); Arribere, Maria [Laboratorio de Analisis por Activacion Neutronica, Centro Atomico Bariloche, 8400 Bariloche (Argentina)

    2008-10-15

    Well preserved volcanic ashes produced in recent events, recovered from sedimentary sequences extracted from three lakes belonging to Nahuel Huapi National Park, Northern Patagonia, were geochemically characterized in order to reveal patterns that allow the identification of the source. Two water bodies are situated in the direct impact area of volcanoes Calbuco and Puyehue-Cordon Caulle, while the third, lake Moreno, is situated in-between. The sedimentary sequences were dated by {sup 210}Pb and {sup 137}Cs techniques; the elemental composition was determined by Instrumental Neutron Activation Analysis. Distinctive patterns were found out when comparing glass shards, and also white pumice but in a lesser degree, of tephra layers extracted from lake Ilon, related mostly to volcano Calbuco events, and lake Nahuel Huapi (Brazo Rincon site), associated to Puyehue-Cordon Caulle eruptions. The geochemical parameters that showed decisive differences were SiO{sub 2} and Na{sub 2}O+K{sub 2}O contents, the Eu anomaly, Rare Earth element ratios; the concentration of incompatible elements Cs, Rb, Th, Hf, Ta and Zr, and the compatible elements Cr and V. The six upper tephra layers extracted from lake Moreno showed geochemical patterns that allowed clear association with Calbuco and Puyehue-Cordon Caulle sources. These results set up the base for tephrochronological applications in historical periods in Nahuel Huapi National Park area.

  7. Io. [theories concerning volcanic activity

    Science.gov (United States)

    Johnson, T. V.; Soderblom, L. A.

    1983-01-01

    A report on the continuing investigation of Io is presented. Gravitational resonance is discussed as the cause of Io's volcanism, and the volcanic activity is explained in terms of sulfur chemistry. Theories concerning the reasons for the two main types of volcanic eruptions on Io are advanced and correlated with geographical features of the satellite. The sulfur and silicate models of the calderas are presented, citing the strengths and weaknesses of each. Problems of the gravitational resonance theory of Io's heat source are then described. Finally, observations of Io planned for the Galileo mission are summarized.

  8. Volcanic Lightning in the Laboratory: The Effect of Ultra-Rapid Melting on Ash Particles

    Science.gov (United States)

    Mueller, S.; Keller, F.; Helo, C.; Buhre, S.; Castro, J. M.

    2016-12-01

    Lightning discharge is a common process occurring at explosive volcanic eruptions. During the formation of ash plumes, the dynamical interaction of ash particles creates charges which can, given a sufficiently large charge gradient, cause lightning discharges within the plume (`plume lightning') or from ground to plume (`near-vent lightning'), respectively. Given the extreme heat release during the short duration of a discharge (potentially > 30.000 K), it is likely that the ash particles suspended in a plume are, in any form, affected by volcanic lightning. Genareau et al. (2015) found evidence of glass spherules and glass aggregates in ash deposits of two explosive eruptions (Eyjafjallajökull, Mt. Redoubt), and linked them to short-term melting processes induced by volcanic lightning (analogue to fulgurites). In order to systematically investigate the potential impact of lightning on air-suspended ash we have designed a new experimental setup. An electric arc between two electrodes is generated by a 400 Amp arc welding device. Ash-sized sample material is then blown into the established lightning arc, and a certain proportion of the injected silicate glasses and/or minerals is melted due to the high temperatures in and around the plasma channel. In a first set of experiments, we have used natural volcanic ash from Laacher See Tephra (Eifel, Germany) in distinct size fractions between 36 and 250 microns, in order to qualitatively investigate melting and amalgamation features. Spherule and aggregate textures similar to those reported by Genareau et al. (2015) were successfully reproduced during these experiments. In a second set of experiments, homogenized phonolitic glass fragments, in different size fractions, were subjected to the electric arc and subsequently analyzed under the EMP, in order to investigate effects of "flash melting" on major element glass chemistry. Genareau K, Wardman JB, Wilson TM, McNutt SR, Izbekov P (2015): Lightning-induced volcanic

  9. Influence of mesostasis in volcanic rocks on the alkali-aggregate reaction

    KAUST Repository

    Tiecher, Francieli

    2012-11-01

    Mesostasis material present in the interstices of volcanic rocks is the main cause of the alkali-aggregate reaction (AAR) in concretes made with these rock aggregates. Mesostasis often is referred to as volcanic glass, because it has amorphous features when analyzed by optical microscopy. However, this study demonstrates that mesostasis in the interstitials of volcanic rocks most often consists of micro to cryptocrystalline mineral phases of quartz, feldspars, and clays. Mesostasis has been identified as having different characteristics, and, thus, this new characterization calls for a re-evaluation of their influence on the reactivity of the volcanic rocks. The main purpose of this study is to correlate the characteristics of mesostasis with the AAR in mortar bars containing basalts and rhyolites. © 2012 Elsevier Ltd. All rights reserved.

  10. Glass Fibers: Quo Vadis?

    Directory of Open Access Journals (Sweden)

    Edith Mäder

    2017-02-01

    Full Text Available Since the early 1930s, the process of melting glass and subsequently forming fibers, in particular discontinuous fiber glass or continuous glass filaments, evolved into commercial-scale manufacturing.[...

  11. Volcanic ash supports a diverse bacterial community in a marine mesocosm

    Science.gov (United States)

    Verena Witt,; Paul M Ayris,; Damby, David; Corrado Cimarelli,; Ulrich Kueppers,; Donald B Dingwell,; Gert Wörheide,

    2017-01-01

    Shallow-water coral reef ecosystems, particularly those already impaired by anthropogenic pressures, may be highly sensitive to disturbances from natural catastrophic events, such as volcanic eruptions. Explosive volcanic eruptions expel large quantities of silicate ash particles into the atmosphere, which can disperse across millions of square kilometres and deposit into coral reef ecosystems. Following heavy ash deposition, mass mortality of reef biota is expected, but little is known about the recovery of post-burial reef ecosystems. Reef regeneration depends partly upon the capacity of the ash deposit to be colonised by waterborne bacterial communities and may be influenced to an unknown extent by the physiochemical properties of the ash substrate itself. To determine the potential for volcanic ash to support pioneer bacterial colonisation, we exposed five well-characterised volcanic and coral reef substrates to a marine aquarium under low light conditions for 3 months: volcanic ash, synthetic volcanic glass, carbonate reef sand, calcite sand and quartz sand. Multivariate statistical analysis of Automated Ribosomal Intergenic Spacer Analysis (ARISA) fingerprinting data demonstrates clear segregation of volcanic substrates from the quartz and coral reef substrates over 3 months of bacterial colonisation. Overall bacterial diversity showed shared and substrate-specific bacterial communities; however, the volcanic ash substrate supported the most diverse bacterial community. These data suggest a significant influence of substrate properties (composition, granulometry and colour) on bacterial settlement. Our findings provide first insights into physicochemical controls on pioneer bacterial colonisation of volcanic ash and highlight the potential for volcanic ash deposits to support bacterial diversity in the aftermath of reef burial, on timescales that could permit cascading effects on larval settlement.

  12. Automatic classification of seismo-volcanic signatures

    Science.gov (United States)

    Malfante, Marielle; Dalla Mura, Mauro; Mars, Jérôme; Macedo, Orlando; Inza, Adolfo; Métaxian, Jean-Philippe

    2017-04-01

    The prediction of volcanic eruptions and the evaluation of their associated risks is still a timely and open issue. For this purpose, several types of signals are recorded in the proximity of volcanoes and then analysed by experts. Typically, seismic signals that are considered as precursor or indicator of an active volcanic phase are detected and manually classified. In this work, we propose an architecture for automatic classification of seismo-volcanic waves. The system we propose is based on supervised machine learning. Specifically, a prediction model is built from a large dataset of labelled examples by the means of a learning algorithm (Support Vector Machine or Random Forest). Four main steps are involved: (i) preprocess the signals, (ii) from each signal, extract features that are useful for the classes discrimination, (iii) use an automatic learning algorithm to train a prediction model and (iv) classify (i.e., assign a semantic label) newly recorded and unlabelled examples. Our main contribution lies in the definition of the feature space used to represent the signals (i.e., in the choice of the features to extract from the data). Feature vectors describe the data in a space of lower dimension with respect to the original one. Ideally, signals are separable in the feature space depending on their classes. For this work, we consider a large set of features (79) gathered from an extensive state of the art in both acoustic and seismic fields. An analysis of this feature set shows that for the application of interest, 11 features are sufficient to discriminate the data. The architecture is tested on 4725 seismic events recorded between June 2006 and September 2011 at Ubinas, the most active volcano of Peru. Six main classes of signals are considered: volcanic tremors (TR), long period (LP), volcano-tectonic (VT), explosion (EXP), hybrids (HIB) and tornillo (TOR). Our model reaches above 90% of accuracy, thereby validating the proposed architecture and the

  13. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  14. Volcanic eruptions observed with infrasound

    Science.gov (United States)

    Johnson, Jeffrey B.; Aster, Richard C.; Kyle, Philip R.

    2004-07-01

    Infrasonic airwaves produced by active volcanoes provide valuable insight into the eruption dynamics. Because the infrasonic pressure field may be directly associated with the flux rate of gas released at a volcanic vent, infrasound also enhances the efficacy of volcanic hazard monitoring and continuous studies of conduit processes. Here we present new results from Erebus, Fuego, and Villarrica volcanoes highlighting uses of infrasound for constraining quantitative eruption parameters, such as eruption duration, source mechanism, and explosive gas flux.

  15. Los volcanes y los hombres

    OpenAIRE

    García, Carmen

    2007-01-01

    Desde las entrañas de la tierra, los volcanes han creado la atmósfera, el agua de los océanos, y esculpido los relieves del planeta: son, pues, los zahoríes de la vida. Existen volcanes que los hombres explotan o cultivan, y otros sobre los cuales se han construido observatorios en los que se llevan a cabo avanzadas investigaciones científicas.

  16. Volcanic hazards and aviation safety

    Science.gov (United States)

    Casadevall, Thomas J.; Thompson, Theodore B.; Ewert, John W.; ,

    1996-01-01

    An aeronautical chart was developed to determine the relative proximity of volcanoes or ash clouds to the airports and flight corridors that may be affected by volcanic debris. The map aims to inform and increase awareness about the close spatial relationship between volcanoes and aviation operations. It shows the locations of the active volcanoes together with selected aeronautical navigation aids and great-circle routes. The map mitigates the threat that volcanic hazards pose to aircraft and improves aviation safety.

  17. Volcanic Zone, New Zealand

    Directory of Open Access Journals (Sweden)

    Graham J. Weir

    2001-01-01

    Full Text Available A conceptual model of the Taupo Volcanic Zone (TVZ is developed, to a depth of 25 km, formed from three constant density layers. The upper layer is formed from eruption products. A constant rate of eruption is assumed, which eventually implies a constant rate of extension, and a constant rate of volumetric creation in the middle and bottom layers. Tectonic extension creates volume which can accomodate magmatic intrusions. Spreading models assume this volume is distributed throughout the whole region, perhaps in vertical dykes, whereas rifting models assume the upper crust is thinned and the volume created lies under this upper crust. Bounds on the heat flow from such magmatic intrusions are calculated. Heat flow calculations are performed and some examples are provided which match the present total heat output from the TVZ of about 4200 MW, but these either have extension rates greater than the low values of about 8 ± 4 mm/a being reported from GPS measurements, or else consider extension rates in the TVZ to have varied over time.

  18. A Disequilibrium Melting Spectrum: Partially Melted Crustal Xenoliths from the Wudalianchi Volcanic Field, NE China.

    Science.gov (United States)

    McLeod, C. L.; McGee, L. E.

    2015-12-01

    Disequilibrium melting has been established as a common process occurring during crustal anatexis and thus demonstrates that crustal assimilation by ascending mantle-derived magmas is likley not a closed system. Observations of extreme compositional heterogeneity within partial melts derived from crustal xenoliths have been documented in several recent examples, however, the retention or transfer of elements to and from residues and glasses, and their relative contributions to potential crustal contaminants warrants further investigation. Sampled lavas from the Huoshaoshan volcano in the Holocene Wudalianchi volcanic field of Northeast China contain crustal xenoliths which preserve a spectrum of partial melting both petrographically and geochemically, thus providing an excellent, natural example of crustal anatexis. Correlations exist between the volume of silicic glass preserved within the xenoliths and bulk rock SiO2 (70-83 wt%), Al2O3 (16-8 wt%), glass 87Sr/86Sr (0.715-0.908), abundances of elements common in feldspars and micas (Sr, Ba, Rb) and elements common in accessory minerals (Y, Zr, Nb). These correlations are likely associated with the consumption of feldspars and micas and the varying retention of accessory phases during partial melting. The xenoliths which contain the greater volumes of silicic glass and residual quartz (interpreted as being the most melted) were found within pahoehoe lava, whilst the least melted xenoliths were found within scoria of the summit cone of Huoshaoshan; thus it is interpreted that the extent of melting is linked to the immersion time in the lava. Small-scale (mm) mingling and transfer of material from the enclosing lava to the xenolith is observed, however, modelling of potential contaminant compositions is inconsistent with crustal contamination during lava petrogenesis. It is inferred that crustal contamination in sampled lavas is localized within the open magmatic system and most likely occurs at the contact zone

  19. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    system; this glass though has a long lifetime before ending up in the waste. Altogether these product types add up to 82% of the production of the European glass industry (IPCC, 2001). Recycling of glass in terms of cleaning and refilling of bottles as well as the use of broken glass in the production......Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...... of new glass containers is well established in the glass industry. This chapter describes briefly howglass is produced and howwaste glass is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of glass recycling....

  20. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...... system; this glass though has a long lifetime before ending up in the waste. Altogether these product types add up to 82% of the production of the European glass industry (IPCC, 2001). Recycling of glass in terms of cleaning and refilling of bottles as well as the use of broken glass in the production...... of new glass containers is well established in the glass industry. This chapter describes briefly howglass is produced and howwaste glass is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of glass recycling....

  1. Oxidation of shallow conduit magma: Insight from μ-XANES analysis on volcanic ash particle

    Science.gov (United States)

    Miwa, T.; Ishibashi, H.; Iguchi, M.

    2014-12-01

    Redox state of magma is important to understand dynamics of volcanic eruptions because magma properties such as composition of degassed volatiles, stability field of minerals, and rheology of magma depend on redox state. To evaluate redox state of magma, Fe3+/ΣFe ratio [= Fe3+/( Fe3++ Fe2+)] of volcanic glass has been measured non-destructively by Fe-K edge μ-XANES (micro X-ray Absorption Near Edge Structure) spectroscopy (e.g., Cottrell and Kelly, 2011). We performed textural, compositional, and Fe-K edge μ-XANES analyses on volcanic ash to infer oxidation process of magma at shallow conduit during eruption at Bromo Volcano, Indonesia. The volcanic ash particles were collected in 24th March 2011 by real-time sampling from ongoing activity. The activity was characterized by strombolian eruption showing magma head ascended to near the ground surface. The ash sample contains two type of volcanic glasses named as Brown and Black glasses (BrG and BlG), based on their color. Textual analysis shows microlite crystallinities are same in the two type of glasses, ranging from 0 to 3 vol.%. EPMA analyses show that all of the glasses have almost identical andesitic composition with SiO2 = 60 wt.%. In contrast, Fe-K edge μ-XANES spectra with the analytical method by Ishibashi et al. (in prep) demonstrate that BrG (Fe3+/ΣFe = 0.20-0.26) is more oxidized than BlG (Fe3+/ΣFe = 0.32-0.60). From combination of the glass composition, the measured Fe3+/ΣFe ratio and 1060 degree C of temperature (Kress and Carmichael, 1991), the oxygen fugacities are estimated to be NNO and NNO+4 for BrG and BlG, respectively. The volcanic glasses preserve syn-eruptive physicochemical conditions by rapid quenching due to their small size ranging from 125 to 250 μm. Our results demonstrate that BrG and BlG magmas are textually and chemically identical but their redox conditions are different at the eruption. The oxidation of magma can be caused by following two processes; 1) diffusive transport

  2. Benefits of a STEAM Collaboration in Newark, New Jersey: Volcano Simulation through a Glass-Making Experience

    Science.gov (United States)

    Gates, Alexander E.

    2017-01-01

    A simulated physical model of volcanic processes using a glass art studio greatly enhanced enthusiasm and learning among urban, middle- to high-school aged, largely underrepresented minority students in Newark, New Jersey. The collaboration of a geoscience department with a glass art studio to create a science, technology, engineering, arts, and…

  3. Magma storage under Iceland's Eastern Volcanic Zone

    Science.gov (United States)

    Maclennan, J.; Neave, D.; Hartley, M. E.; Edmonds, M.; Thordarson, T.; Morgan, D. J.

    2014-12-01

    The Eastern Volcanic Zone (EVZ) of Iceland is defined by a number of volcanic systems and large basaltic eruptions occur both through central volcanoes (e.g. Grímsvötn) and on associated fissure rows (e.g. Laki, Eldgjá). We have collected a large quantity of micro-analytical data from a number of EVZ eruptions, with the aim of identifying common processes that occur in the premonitory stages of significant volcanic events. Here, we focus on the AD 1783 Laki event, the early postglacial Saksunarvatn tephra and the sub-glacially erupted Skuggafjöll tindar and for each of these eruptions we have >100 olivine-hosted or plagioclase-hosted melt inclusion analyses for major, trace and volatile elements. These large datasets are vital for understanding the history of melt evolution in the plumbing system of basaltic volcanoes. Diverse trace element compositions in melt inclusions hosted in primitive macrocrysts (i.e. Fo>84, An>84) indicate that the mantle melts supplied to the plumbing system of EVZ eruptions are highly variable in composition. Concurrent mixing and crystallisation of these melts occurs in crustal magma bodies. The levels of the deepest of these magma bodies are not well constrained by EVZ petrology, with only a handful of high-CO2 melt inclusions from Laki providing evidence for magma supply from >5 kbar. In contrast, the volatile contents of melt inclusions in evolved macrocrysts, which are close to equilibrium with the carrier liquids, indicate that final depths of inclusion entrapment are 0.5-2 kbar. The major element composition of the matrix glasses shows that the final pressure of equilibration between the melt and its macrocryst phases also occurred at 0.5-2 kbar. The relationship between these pressures and seismic/geodetic estimates of chamber depths needs to be carefully evaluated. The melt inclusion and macrocryst compositional record indicates that injection of porphyritic, gas-rich primitive melt into evolved/enriched and degassed shallow

  4. Volatile Evolution of Magma Associated with the Solchiaro Eruption in the Phlegrean Volcanic District (Italy)

    Science.gov (United States)

    Esposito, R.; Bodnar, R. J.; de Vivo, B.; Lima, A.; Fedele, L.; Shimizu, N.; Hunter, J.

    2009-12-01

    The Phlegrean volcanic district (PVD) in southern Italy is one of the best known volcanic hazard areas in the world. More than 1.5 million people live in close proximity to the volcanic centers. The PVD comprises three volcanic fields: the Campi Flegrei caldera and the islands of Ischia and Procida. We studied volatiles plus major and trace elements in the magma associated with the Solchiaro eruption on the Island of Procida, Italy, to gain a better understanding of the relationship between pre-eruptive volatiles and magmatic evolution. The Solchiaro eruption is one of the more primitive products erupted in the PVD and provides information on the source of later more evolved magmas associated with this volcanic system. The composition of the magma before eruption was determined by analyzing 104 melt inclusions (MIs) in forsteritic olivine, glass embayment plus rim glasses, and high vesciculated glasses selected from 4 representative samples. The composition of MIs was recalculated and ranges from basaltic to trachy-basaltic. Among major elements potassium shows the highest variability, from 0.5 to 6 wt%. MI define a continuous trend based on major and minor element compositions. Embayments matrix glass and high vesciculated glasses define a field that suggests a discontinuous process. Compatible to incompatible trace element ratios in early melts are highly variable and represent the melt phase before or at the very beginning of assimilation-fractional crystallization (FCA) processes. Intermediate melt compositions reflect continuing FCA processes, late melt compositions suggest that the FCA process was aborted before eruption. Volatile contents of early melt are highly variable and reflect source heterogeneities, and the melts are interpreted to be undersaturated. Intermediate melts were volatile saturated and H2O-CO2 contents define a degassing path. Depths of trapping of MI range from 4.4 to 2.2 km, and are calculated based on Newman and Lowenstern (2002) and

  5. Mantle updrafts and mechanisms of oceanic volcanism

    Science.gov (United States)

    Anderson, Don L.; Natland, James H.

    2014-10-01

    Convection in an isolated planet is characterized by narrow downwellings and broad updrafts-consequences of Archimedes' principle, the cooling required by the second law of thermodynamics, and the effect of compression on material properties. A mature cooling planet with a conductive low-viscosity core develops a thick insulating surface boundary layer with a thermal maximum, a subadiabatic interior, and a cooling highly conductive but thin boundary layer above the core. Parts of the surface layer sink into the interior, displacing older, colder material, which is entrained by spreading ridges. Magma characteristics of intraplate volcanoes are derived from within the upper boundary layer. Upper mantle features revealed by seismic tomography and that are apparently related to surface volcanoes are intrinsically broad and are not due to unresolved narrow jets. Their morphology, aspect ratio, inferred ascent rate, and temperature show that they are passively responding to downward fluxes, as appropriate for a cooling planet that is losing more heat through its surface than is being provided from its core or from radioactive heating. Response to doward flux is the inverse of the heat-pipe/mantle-plume mode of planetary cooling. Shear-driven melt extraction from the surface boundary layer explains volcanic provinces such as Yellowstone, Hawaii, and Samoa. Passive upwellings from deeper in the upper mantle feed ridges and near-ridge hotspots, and others interact with the sheared and metasomatized surface layer. Normal plate tectonic processes are responsible both for plate boundary and intraplate swells and volcanism.

  6. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina

    primitive basalts and trachybasalts but also more evolved samples from the retroarc region and the larger volcanoes Payún Matrú and Payún Liso are presented. The samples cover a broad range of compositions from intraplate lavas similar to ocean island basalts to arc andesites. A common feature found...... Pleistocene times. These basalts mark the end of a period of shallow subduction of the Nazca slab beneath the Payenia province and volcanism in the Nevado volcanic field apparently followed the downwarping slab in a north-northwest direction ending in the Northern Segment. The northern Payenia basalts...... the literature. The Nevado basalts have been modelled by 4-10 % melting of a primitive mantle added 1-5 % upper continental crust. In the southern Payenia province, intraplate basalts dominate. The samples from the Payún Matrú and Río Colorado volcanic fields are apparently unaffected by the subducting slab...

  7. Glass-silicon column

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Conrad M.

    2003-12-30

    A glass-silicon column that can operate in temperature variations between room temperature and about 450.degree. C. The glass-silicon column includes large area glass, such as a thin Corning 7740 boron-silicate glass bonded to a silicon wafer, with an electrode embedded in or mounted on glass of the column, and with a self alignment silicon post/glass hole structure. The glass/silicon components are bonded, for example be anodic bonding. In one embodiment, the column includes two outer layers of silicon each bonded to an inner layer of glass, with an electrode imbedded between the layers of glass, and with at least one self alignment hole and post arrangement. The electrode functions as a column heater, and one glass/silicon component is provided with a number of flow channels adjacent the bonded surfaces.

  8. Episodes of volcanic activity and their environmental effects in the Okinawa Trough during the last 150 ka

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A piston core Z14-6 was used in this study. The core, 896 cm long, was collected from eastern slope of the Okinawa Trough (27°07′N, 127°27′E, water depth 739m). The δ18O and δ13C values of the sediment bearing planktonic foraminifera G. sacculifer and N. dutertrei were determined; and the abundance of volcanic glass was analyzed. The volcanic glass content high occurred in early stage of polar ice-sheet growth period, or the beginning of cold climate periods corresponding to Milankovitch cycles (Peak Ⅰ, Ⅱ and Ⅴ are corresponding to the beginnings of oxygen isotopic stages 2, 4 and 6, and Peak Ⅲ and Ⅳ are matching oxygen isotopic stage 5b-5d.). It might be possible that volcanic episodes and climate changes were responding to orbital forcing in the Okinawa Trough in late Quaternary. The δ18O difference between N. dutertrei and G. sacculifer shows no clear correlation to the volcanic glass content high, which suggests that the volcanic eruptions did not influence the structure of upper water column. However, the low δ13C difference between G. sacculifer and N. dutertrei is coeval with the volcanic glass high or sub-high content. This fact suggests that volcanic eruptions might influence the reduction in vertical nutritional gradient and carbon cycle process in upper water column. A possible mechanism is that huge quantity of ash and dust had weakened the light intensity, resulting in photosynthesis reduction, productivity decrease, and biological pumping.

  9. Bedout basement rise, offshore northwestern Australia: evidence of an unshocked mafic volcanic hyaloclastite volcanic breccia

    Science.gov (United States)

    Glikson, A.

    2004-12-01

    Core samples from Bedout-1 (3035.8-3044.95 m.), Bedout basement rise, offshore northwestern Australia, were examined by optical microscopy, SEM, EDS and WDS spectrometry. At this stratigraphic depth level Becker et al. (2004) interpret cryptocrystalline alteration zones around and within plagioclase in terms of shock-induced transformation of feldspar into diaplectic maskelynite glass _u postulating a ~200 km-large impact structure and thereby an impact connection of the Permian-Triassic boundary mass extinction. However, the breccia is dominated by fragments of microlitic basalt and ophitic-textured dolerite with well preserved igneous textures, showing no evidence of shock metamorphism. Euhedral pseudomorphs of chlorite and amphibole, probably after pyroxene, protrude into or are enveloped by euhedral albite-twinned calcic plagioclase (andesine to bytownite). Minor phases include euhedral ilmenite needles and subhedral magnetite grains. Plagioclase is altered by cryptocrystalline albite and microcrystalline albite-chlorite matrix along crystal boundaries, along twin lamella and within internal oscillatory crystal zones, consistent with burial metamorphosed hydrovolcanic basalts and spilites (e.g. Amstutz, 1974). The volcanic fragments are set within, and injected by, microcrystalline intergranular mesostasis of mixed mineral fragments and volcanic meta-glass. Becker et al. (2004) refer to the breccia in part as product of Mg-rich sediments (e.g. dolomites). However, apart from the pristine igneous textures of the breccia, the transition element levels (chlorite in dolerite fragment "C Ni 97-160 ppm; Co 75-152 ppm; Cu 69-204 ppm; mesostasis "C Ni 29-45 ppm; Co 18-52 ppm; Cu 26-110 ppm) are consistent with Fe-rich basalts but exceed common abundances in carbonates and marls (BVTP, 1981; Wedepohl, 1978). No shock metamorphic features, such as planar deformation features (PDF), are observed in the feldspar or in any other phases. No criteria for discriminating

  10. Atmospheric chemistry in volcanic plumes.

    Science.gov (United States)

    von Glasow, Roland

    2010-04-13

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis.

  11. Climatic impact of volcanic eruptions

    Science.gov (United States)

    Rampino, Michael R.

    1991-01-01

    Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

  12. Morphology and composition of condensates on Apollo 17 orange and black glass

    Science.gov (United States)

    Mckay, David S.; Wentworth, Sue J.

    1992-01-01

    Lunar soil sample 74220 and core samples 74001/2 consist mainly of orange glass droplets, droplet fragments, and their crystallized equivalents. These samples are now generally accepted to be pyroclastic ejecta from early lunar volcanic eruptions. It has been known since early examination of these samples that they contain surface coatings and material rich in volatile condensible phases, including S, Zn, F, Cl, and many volatile metals. The volatiles associated with these orange and black glasses (and the Apollo 15 green glasses) may provide important clues in understanding the differentiation and volcanic history of the Moon. In addition, condensible volatiles can be mobilized and concentrated by volcanic processes. We have reviewed many of our existing photomicrographs and energy dispersive analysis (EDXA) of grain surfaces and have reexamined some of our older SEM mounts using an improved EDXA system capable of light-element detection and analysis (oxygen, nitrogen, and carbon). The results from these investigations are presented.

  13. Aurorae and Volcanic Eruptions

    Science.gov (United States)

    2001-06-01

    Thermal-IR Observations of Jupiter and Io with ISAAC at the VLT Summary Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). . They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io , the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere. PR Photo 21a/01 : ISAAC image of Jupiter (L-band: 3.5-4.0 µm) . PR Photo 21b/01 : ISAAC image of Jupiter (Narrow-band 4.07 µm) . PR Photo 21c/01 : ISAAC image of Jupiter (Narrow-band 3.28 µm) . PR Photo 21d/01 : ISAAC image of Jupiter (Narrow-band 3.21 µm) . PR Photo 21e/01 : ISAAC image of the Jovian aurorae (false-colour). PR Photo 21f/01 : ISAAC image of volcanic activity on Io . Addendum : The Jovian aurorae and polar haze. Aladdin Meets Jupiter Thermal-infrared images of Jupiter and its volcanic moon Io have been obtained during a series of system tests with the new Aladdin detector in the Infrared Spectrometer And Array Camera (ISAAC) , in combination with an upgrade of the ESO-developed detector control electronics IRACE. This state-of-the-art instrument is attached to the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory. The observations were made on November 14, 2000, through various filters that isolate selected wavebands in the thermal-infrared spectral region [1]. They include a broad-band L-filter (wavelength interval 3.5 - 4.0 µm) as well as several narrow-band filters (3.21, 3.28 and 4.07 µm). The filters allow to record the light from different components of the Jovian atmosphere

  14. Geopulsation, Volcanism and Astronomical Periods

    Institute of Scientific and Technical Information of China (English)

    Yang Xuexiang; Chen Dianyou; Yang Xiaoying; Yang Shuchen

    2000-01-01

    Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.

  15. Volcanic eruptions and solar activity

    Science.gov (United States)

    Stothers, Richard B.

    1989-01-01

    The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

  16. Geochemical study for volcanic surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Panichi, C.; La Ruffa, G. [Consiglio Nazionale delle Ricerche, International Institute for Geothermal Research Ghezzano, PI (Italy)

    2000-07-01

    For years, geologists have been striving to reconstruct volcanic eruptions from the analysis of pyroclastic deposits and lava flows on the surface of the earth and in the oceans. This effort has produced valuable information on volcanic petrology and magma generation, separation, mixing, crystallisation, and interaction with water in phreatomagmatic and submarine eruptions. The volcanological process are tied to the dynamics of the earth's crust and lithosphere. The mantle, subducted oceanic crust, and continental crust contain different rock types and are sources of different magmas. Magmas consist primarily of completely or partially molten silicates containing volatile materials either dissolved in the melt or as bubbles of gas. The silicate and volatile portions affect the physical properties of magma and, therefore, the nature of a volcanic eruption.

  17. Models of volcanic eruption hazards

    Energy Technology Data Exchange (ETDEWEB)

    Wohletz, K.H.

    1992-01-01

    Volcanic eruptions pose an ever present but poorly constrained hazard to life and property for geothermal installations in volcanic areas. Because eruptions occur sporadically and may limit field access, quantitative and systematic field studies of eruptions are difficult to complete. Circumventing this difficulty, laboratory models and numerical simulations are pivotal in building our understanding of eruptions. For example, the results of fuel-coolant interaction experiments show that magma-water interaction controls many eruption styles. Applying these results, increasing numbers of field studies now document and interpret the role of external water eruptions. Similarly, numerical simulations solve the fundamental physics of high-speed fluid flow and give quantitative predictions that elucidate the complexities of pyroclastic flows and surges. A primary goal of these models is to guide geologists in searching for critical field relationships and making their interpretations. Coupled with field work, modeling is beginning to allow more quantitative and predictive volcanic hazard assessments.

  18. Classification of volcanic ash particles from Sakurajima volcano using CCD camera image and cluster analysis

    Science.gov (United States)

    Miwa, T.; Shimano, T.; Nishimura, T.

    2012-12-01

    Quantitative and speedy characterization of volcanic ash particle is needed to conduct a petrologic monitoring of ongoing eruption. We develop a new simple system using CCD camera images for quantitatively characterizing ash properties, and apply it to volcanic ash collected at Sakurajima. Our method characterizes volcanic ash particles by 1) apparent luminance through RGB filters and 2) a quasi-fractal dimension of the shape of particles. Using a monochromatic CCD camera (Starshoot by Orion Co. LTD.) attached to a stereoscopic microscope, we capture digital images of ash particles that are set on a glass plate under which white colored paper or polarizing plate is set. The images of 1390 x 1080 pixels are taken through three kinds of color filters (Red, Green and Blue) under incident-light and transmitted-light through polarizing plate. Brightness of the light sources is set to be constant, and luminance is calibrated by white and black colored papers. About fifteen ash particles are set on the plate at the same time, and their images are saved with a bit map format. We first extract the outlines of particles from the image taken under transmitted-light through polarizing plate. Then, luminances for each color are represented by 256 tones at each pixel in the particles, and the average and its standard deviation are calculated for each ash particle. We also measure the quasi-fractal dimension (qfd) of ash particles. We perform box counting that counts the number of boxes which consist of 1×1 and 128×128 pixels that catch the area of the ash particle. The qfd is estimated by taking the ratio of the former number to the latter one. These parameters are calculated by using software R. We characterize volcanic ash from Showa crater of Sakurajima collected in two days (Feb 09, 2009, and Jan 13, 2010), and apply cluster analyses. Dendrograms are formed from the qfd and following four parameters calculated from the luminance: Rf=R/(R+G+B), G=G/(R+G+B), B=B/(R+G+B), and

  19. Volcanic ash at Santiaguito dome complex, Guatemala

    Science.gov (United States)

    Hornby, Adrian; Kendrick, Jackie; Lavallée, Yan; Cimarelli, Corrado; von Aulock, Felix; Rhodes, Emma; Kennedy, Ben; Wadsworth, Fabian

    2015-04-01

    Dome-building volcanoes often suffer episodic explosions. Examination of eruptive activity at Santiaguito dome complex (Guatemala) reveals that gas-and-ash explosions are concordant with rapid inflation/ deflation cycles of the active dome. During these explosions strain is accommodated along marginal faults, where tensional fracture mechanisms and friction dominate, complicating the model of ash generation by bubble rupture in magma. Here, we describe textural features, morphology and petrology of ash collected before, during and after a dome collapse event at Santiaguito dome complex on the 28th November 2012. We use QEM-scan (on more than 35000 grains), laser diffraction granulometry and optical and scanning microscopy to characterise the samples. The ash samples show a bimodal size distribution and a range of textures, crystal content and morphologies. The ash particles are angular to sub-angular and are relatively dense, so do not appear to comprise of pore walls. Instead the ash is generally blocky (>70%), similar to the products of shear magma failure. The ash samples show minor variation before, during and after dome collapse, specifically having a smaller grain size and a higher fraction of phenocrysts fragments before collapse. Textural analysis shows vestiges of chemically heterogeneous glass (melt) filaments originating from the crystals and crosscut by fragmentation during volcanic ash formation. High-velocity friction can induce melting of dome lavas, producing similar disequilibrium melting textures. This work shows the importance of deformation mechanisms in ash generation at lava domes and during Vulcanian activity.

  20. Recurrence models of volcanic events: Applications to volcanic risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.M. [Los Alamos National Lab., Las Vegas, NV (United States); Picard, R.; Valentine, G. [Los Alamos National Lab., NM (United States); Perry, F.V. [New Mexico Univ., Albuquerque, NM (United States)

    1992-03-01

    An assessment of the risk of future volcanism has been conducted for isolation of high-level radioactive waste at the potential Yucca Mountain site in southern Nevada. Risk used in this context refers to a combined assessment of the probability and consequences of future volcanic activity. Past studies established bounds on the probability of magmatic disruption of a repository. These bounds were revised as additional data were gathered from site characterization studies. The probability of direct intersection of a potential repository located in an eight km{sup 2} area of Yucca Mountain by ascending basalt magma was bounded by the range of 10{sup {minus}8} to 10{sup {minus}10} yr{sup {minus}1 2}. The consequences of magmatic disruption of a repository were estimated in previous studies to be limited. The exact releases from such an event are dependent on the strike of an intruding basalt dike relative to the repository geometry, the timing of the basaltic event relative to the age of the radioactive waste and the mechanisms of release and dispersal of the waste radionuclides in the accessible environment. The combined low probability of repository disruption and the limited releases associated with this event established the basis for the judgement that the risk of future volcanism was relatively low. It was reasoned that that risk of future volcanism was not likely to result in disqualification of the potential Yucca Mountain site.

  1. Controls on volcanism at intraplate basaltic volcanic fields

    Science.gov (United States)

    van den Hove, Jackson C.; Van Otterloo, Jozua; Betts, Peter G.; Ailleres, Laurent; Cas, Ray A. F.

    2017-02-01

    A broad range of controlling mechanisms is described for intraplate basaltic volcanic fields (IBVFs) in the literature. These correspond with those relating to shallow tectonic processes and to deep mantle plumes. Accurate measurement of the physical parameters of intraplate volcanism is fundamental to gain an understanding of the controlling factors that influence the scale and location of a specific IBVF. Detailed volume and geochronology data are required for this; however, these are not available for many IBVFs. In this study the primary controls on magma genesis and transportation are established for the Pliocene-Recent Newer Volcanics Province (NVP) of south-eastern Australia as a case-study for one of such IBVF. The NVP is a large and spatio-temporally complex IBVF that has been described as either being related to a deep mantle plume, or upper mantle and crustal processes. We use innovative high resolution aeromagnetic and 3D modelling analysis, constrained by well-log data, to calculate its dimensions, volume and long-term eruptive flux. Our estimates suggest volcanic deposits cover an area of 23,100 ± 530 km2 and have a preserved dense rock equivalent of erupted volcanics of least 680 km3, and may have been as large as 900 km3. The long-term mean eruptive flux of the NVP is estimated between 0.15 and 0.20 km3/ka, which is relatively high compared with other IBVFs. Our comparison with other IBVFs shows eruptive fluxes vary up to two orders of magnitude within individual fields. Most examples where a range of eruptive flux is available for an IBVF show a correlation between eruptive flux and the rate of local tectonic processes, suggesting tectonic control. Limited age dating of the NVP has been used to suggest there were pulses in its eruptive flux, which are not resolvable using current data. These changes in eruptive flux are not directly relatable to the rate of any interpreted tectonic driver such as edge-driven convection. However, the NVP and other

  2. Ground-based analysis of volcanic ash plumes using a new multispectral thermal infrared camera approach

    Science.gov (United States)

    Williams, D.; Ramsey, M. S.

    2015-12-01

    Volcanic plumes are complex mixtures of mineral, lithic and glass fragments of varying size, together with multiple gas species. These plumes vary in size dependent on a number of factors, including vent diameter, magma composition and the quantity of volatiles within a melt. However, determining the chemical and mineralogical properties of a volcanic plume immediately after an eruption is a great challenge. Thermal infrared (TIR) satellite remote sensing of these plumes is routinely used to calculate the volcanic ash particle size variations and sulfur dioxide concentration. These analyses are commonly performed using high temporal, low spatial resolution satellites, which can only reveal large scale trends. What is lacking is a high spatial resolution study specifically of the properties of the proximal plumes. Using the emissive properties of volcanic ash, a new method has been developed to determine the plume's particle size and petrology in spaceborne and ground-based TIR data. A multispectral adaptation of a FLIR TIR camera has been developed that simulates the TIR channels found on several current orbital instruments. Using this instrument, data of volcanic plumes from Fuego and Santiaguito volcanoes in Guatemala were recently obtained Preliminary results indicate that the camera is capable of detecting silicate absorption features in the emissivity spectra over the TIR wavelength range, which can be linked to both mineral chemistry and particle size. It is hoped that this technique can be expanded to isolate different volcanic species within a plume, validate the orbital data, and ultimately to use the results to better inform eruption dynamics modelling.

  3. Effect of gas emissions from Tianchi volcano (NE China) on environment and its potential volcanic hazards

    Institute of Scientific and Technical Information of China (English)

    GUO; Zhengfu; LIU; Jiaqi; HAN; Jingtai; HE; Huaiyu; DAI; Guoliang; YOU; Haitao

    2006-01-01

    The Tianchi volcano in the Changbai Mountains is located on the boundary between China and North Korea. There are many times of eruptions of the Tianchi volcano during the Holocene. One of its large eruptions occurred around 1000 years ago dated by 14C method and historical records. Composition of products of the largest Tianchi volcanic eruption studied is characterized by comenditic Plinian fallout and unwelded ignimbrite, which are mainly distributed in China and North Korea. Caldera is about 4.4 km long and 3.4 km wide, which had filled with water (e.g. Tianchi Lake). The Tianchi volcanic cone is about 2700 m high above sea level. The Tianchi Lake is located on the summit of the volcanic cone, that is also highest peak of the Changbai Mountains in northeastern China. This study analyzed Cl, F, S and H2O concentrations of melt inclusions in the phenocryst minerals (anorthoclase and quartz) and co-existing matrix glasses using the electron microprobe and estimated environmental effect of Tianchi volcanic gases. The authors proposed a new method to evaluate future eruption of active volcano and estimate potential volcanic hazards based on contents of volatile emissions. Using this method, we made a perspective of future volcanic hazard in this region.

  4. lead glass brick

    CERN Multimedia

    When you look through the glass at a picture behind, the picture appears raised up because light is slowed down in the dense glass. It is this density (4.06 gcm-3) that makes lead glass attractive to physicists. The refractive index of the glass is 1.708 at 400nm (violet light), meaning that light travels in the glass at about 58% its normal speed. At CERN, the OPAL detector uses some 12000 blocks of glass like this to measure particle energies.

  5. A quantitative model for volcanic hazard assessment

    OpenAIRE

    W. Marzocchi; Sandri, L.; Furlan, C

    2006-01-01

    Volcanic hazard assessment is a basic ingredient for risk-based decision-making in land-use planning and emergency management. Volcanic hazard is defined as the probability of any particular area being affected by a destructive volcanic event within a given period of time (Fournier d’Albe 1979). The probabilistic nature of such an important issue derives from the fact that volcanic activity is a complex process, characterized by several and usually unknown degrees o...

  6. Widespread Weathered Glass on the Surface of Mars

    Science.gov (United States)

    Horgan, Briony; Bell, James F., III

    2012-01-01

    Low albedo sediments cover >10(exp 7) sq km in the northern lowlands of Mars, but the composition and origin of these widespread deposits have remained ambiguous despite many previous investigations. Here we use near-infrared spectra acquired by the Mars Express OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activite') imaging spectrometer to show that these sediments exhibit spectral characteristics that are consistent with both high abundances of iron-bearing glass and silica-enriched leached rinds on glass. This interpretation is supported by observations of low-albedo soil grains with possible rinds at the Phoenix Mars Lander landing site in the northern lowlands. By comparison with the extensive glass-rich dune fields and sand sheets of Iceland, we propose an explosive volcanic origin for these glass-rich sediments. We also propose that the glassy remnant rinds on the sediments are the result of post-depositional alteration, as these rinds are commonly formed in arid terrestrial volcanic environments during water-limited, moderately acidic leaching. These weathered, glass-rich deposits in the northern lowlands are also colocated with the strongest concentrations of a major global compositional surface type previously identified in mid-infrared spectra, suggesting that they may be representative of global processes. Our results provide potential confirmation of models suggesting that explosive volcanism has been widespread on Mars, and also raise the possibilities that glass-rich volcaniclastics are a major source of eolian sand on Mars and that widespread surficial aqueous alteration has occurred under Amazonian climatic conditions.

  7. Volcanic forcing in decadal forecasts

    Science.gov (United States)

    Ménégoz, Martin; Doblas-Reyes, Francisco; Guemas, Virginie; Asif, Muhammad; Prodhomme, chloe

    2016-04-01

    Volcanic eruptions can significantly impact the climate system, by injecting large amounts of particles into the stratosphere. By reflecting backward the solar radiation, these particles cool the troposphere, and by absorbing the longwave radiation, they warm the stratosphere. As a consequence of this radiative forcing, the global mean surface temperature can decrease by several tenths of degrees. However, large eruptions are also associated to a complex dynamical response of the climate system that is particularly tricky do understand regarding the low number of available observations. Observations seem to show an increase of the positive phases of the Northern Atlantic Oscillation (NAO) the two winters following large eruptions, associated to positive temperature anomalies over the Eurasian continent. The summers following large eruptions are generally particularly cold, especially over the continents of the Northern Hemisphere. Overall, it is really challenging to forecast the climate response to large eruptions, as it is both modulated by, and superimposed to the climate background conditions, largely driven themselves by internal variability at seasonal to decadal scales. This work describes the additional skill of a forecast system used for seasonal and decadal predictions when it includes observed volcanic forcing over the last decades. An idealized volcanic forcing that could be used for real-time forecasts is also evaluated. This work consists in a base for forecasts that will be performed in the context of the next large volcanic eruption.

  8. Delimitation of volcanic edifices for landscape characterization and planning

    Science.gov (United States)

    Melis, Maria Teresa; Mundula, Filippo; Dessì, Francesco; Danila Patta, Elisabetta; Funedda, Antonio; Cioni, Raffaello

    2014-05-01

    The European Landscape Convention, recently adopted in Italy, indicates specific landforms to be selected as special protected sites. Active and inactive volcanic edifices, defined as the products of evolution of aggradational (lava effusion, pyroclastic deposition, magma intrusion) and degradational processes (erosion, deformation, gravitative phenomena), are one of the specific landforms to be protected. In order to protect these sites, management and planning measures are to be defined and shared with the local communities. In the framework of the Regional Landscape Management Plan of Sardinia (Italy), a detailed study aimed at identifying and delimiting Cenozoic volcanic edifices was performed. The large geological and morphological variability of the volcanic edifices of Sardinia in terms of type, dimension, age, integrity (a measure of the wholeness and intactnes of the volcanic edifice), geology and paleomorphology of the substrate, does not allow the definition of an automatic procedure for extracting the boundaries to delimit the volcanic edifices. In addition, quantitative geomorphological studies in the field of volcanology are confined to specific volcano types, and landscape literature does not suggest any universal criteria for delimiting volcanic edifices, except for the use of the concave breaks in slope at their base (Euillades et al., Computers and Geosciences, 2013). As this simple criterion can be unequivocally applied only in the ideal case of symmetric cones or domes built up on a planar surface, we developed a multidisciplinary methodology based on the integrated analysis of geological, geomorphological and morphometrical data of each edifice. The process of selection and delimitation of the volcanic edifices is the result of the following steps: i) a literature based delimitation of the volcanic edifice; ii) a preliminary delimitation through photo-interpretation and the use of geological criteria; and iii) a final refinement based on the

  9. A Volcanic Hydrogen Habitable Zone

    Science.gov (United States)

    Ramirez, Ramses M.; Kaltenegger, Lisa

    2017-03-01

    The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N2–CO2–H2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N2–CO2–H2O–H2) can be sustained as long as volcanic H2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H2 warming is reduced in dense H2O atmospheres. The atmospheric scale heights of such volcanic H2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

  10. ACTIVITIES OF ACACIA NILOTICA EXTRACTS

    African Journals Online (AJOL)

    DR. AMINU

    The water, chloroform and interface fractions were separated in glass ... (Ciulei, 1994), saponins (Turner and Brain, 1975), .... computer loaded with Finney program (Guerrero and. Robledo .... interface extracts appears to have the highest.

  11. Microstructuring of glasses

    CERN Document Server

    Hülsenberg, Dagmar; Bismarck, Alexander

    2008-01-01

    As microstructured glass becomes increasingly important for microsystems technology, the main application fields include micro-fluidic systems, micro-analysis systems, sensors, micro-actuators and implants. And, because glass has quite distinct properties from silicon, PMMA and metals, applications exist where only glass devices meet the requirements. The main advantages of glass derive from its amorphous nature, the precondition for its - theoretically - direction-independent geometric structurability. Microstructuring of Glasses deals with the amorphous state, various glass compositions and their properties, the interactions between glasses and the electromagnetic waves used to modify it. Also treated in detail are methods for influencing the geometrical microstructure of glasses by mechanical, chemical, thermal, optical, and electrical treatment, and the methods and equipment required to produce actual microdevices.

  12. Sr, Nd, Pb Isotope geochemistry and magma evolution of the potassic volcanic rocks, Wudalianchi, Northeast China

    Science.gov (United States)

    Junwen, W.; Guanghong, X.; Tatsumoto, M.; Basu, A.R.

    1989-01-01

    Wudalianchi volcanic rocks are the most typical Cenozoic potassic volcanic rocks in eastern China. Compositional comparisons between whole rocks and glasses of various occurrences indicate that the magma tends to become rich in silica and alkalis as a result of crystal differentiation in the course of evolution. They are unique in isotopic composition with more radiogenic Sr but less radiogenic Pb.87Sr /86 Sr is higher and143Nd/144Nd is lower than the undifferentiated global values. In comparison to continental potash volcanic rocks, Pb isotopes are apparently lower. These various threads of evidence indicate that the rocks were derived from a primary enriched mantle which had not been subjected to reworking and shows no sign of incorporation of crustal material. The correlation between Pb and Sr suggests the regional heterogeneity in the upper mantle in terms of chemical composition. ?? 1989 Institute of Geochemistry, Chinese Academy of Sciences.

  13. Infrared Transparent Selenide Glasses.

    Science.gov (United States)

    1997-03-14

    crystalline halides, silica and fluoride glasses, and chalcogenide glasses. Crystalline halides undergo plastic deformation and are hygroscopic...mainly for applications operating at wavelengths less than 3 microns. Silicate and fluoride glasses have been developed as optical fiber amplifiers...activity. Preferred rare earths includes praseodymium, neodymium, erbium, cerium , dysprosium, holmium, thulium, terbium, ytterbium or mixtures of

  14. How Volcanism Controls Climate Change

    Science.gov (United States)

    Ward, P. L.

    2013-12-01

    Large explosive volcanoes eject megatons of sulfur dioxide into the lower stratosphere where it spreads around the world within months and is oxidized slowly to form a sulfuric-acid aerosol with particle sizes that grow large enough to reflect and scatter solar radiation, cooling Earth ~0.5C for up to 3 years. Explosive eruptions also deplete total column ozone ~6% causing up to 3C winter warming at mid-latitudes over continents. Global cooling predominates. Extrusive, basaltic volcanoes deplete ozone ~6% but do not eject much sulfur dioxide into the lower stratosphere, causing net global warming. Anthropogenic chlorofluorocarbons (CFCs) deplete ozone ~3% for up to a century while each volcanic eruption, even small ones, depletes ozone twice as much but for less than a decade through eruption of halogens and ensuing photochemical processes. The 2010 eruption of Eyjafjallajökull, the 2011 eruption of Grímsvötn, plus anthropogenic CFCs depleted ozone over Toronto Canada 14% in 2012, causing an unusually warm winter and drought. Total column ozone determines how much solar ultraviolet energy with wavelengths between 290 and 340 nanometers reaches Earth where it is absorbed most efficiently by the ocean. A 25% depletion of ozone increases the amount of this radiation reaching Earth by 1 W m-2 for overhead sun and 0.25 W m-2 for a solar zenith angle of 70 degrees. The tropopause is the boundary between the troposphere heated from below by a sun-warmed Earth and the stratosphere heated from above by the Sun through photodissociation primarily of oxygen and ozone. The mean annual height of the tropopause increased ~160 m between 1980 and 2004 at the same time that northern mid-latitude total column ozone was depleted by ~4%, the lower stratosphere cooled ~2C, the upper troposphere warmed ~0.1C, and mean surface temperatures in the northern hemisphere rose ~0.5C. Regional total ozone columns are observed to increase as rapidly as 20% within 5 hours with an associated 5

  15. Late Cenozoic volcanism in the western Woodlark Basin area, SW Pacific: the sources of marine volcanic ash layers based on their elemental and Sr-Nd isotope compositions

    Science.gov (United States)

    Lackschewitz, K. S.; Mertz, D. F.; Devey, C. W.; Garbe-Schönberg, C.-D.

    2002-12-01

    Tephra fallout layers and volcaniclastic deposits, derived from volcanic sources around and on the Papuan Peninsula, form a substantial part of the Woodlark Basin marine sedimentary succession. Sampling by the Ocean Drilling Program Leg 180 in the western Woodlark Basin provides the opportunity to document the distribution of the volcanically-derived components as well as to evaluate their chronology, chemistry, and isotope compositions in order to gain information on the volcanic sources and original magmatic systems. Glass shards selected from 57 volcanogenic layers within the sampled Pliocene-Pleistocene sedimentary sequence show predominantly rhyolitic compositions, with subordinate basaltic andesites, basaltic trachy-andesites, andesites, trachy-andesites, dacites, and phonolites. It was possible to correlate only a few of the volcanogenic layers between sites using geochemical and age information apparently because of the formation of strongly compartmentalised sedimentary realms on this actively rifting margin. In many cases it was possible to correlate Leg 180 volcanic components with their eruption source areas based on chemical and isotope compositions. Likely sources for a considerable number of the volcanogenic deposits are Moresby and Dawson Strait volcanoes (D'Entrecasteaux Islands region) for high-K calc-alkaline glasses. The Dawson Strait volcanoes appear to represent the source for five peralkaline tephra layers. One basaltic andesitic volcaniclastic layer shows affinities to basaltic andesites from the Woodlark spreading tip and Cheshire Seamount. For other layers, a clear identification of the sources proved impossible, although their isotope and chemical signatures suggest similarities to south-west Pacific subduction volcanism, e.g. New Britain and Tonga-Kermadec island arcs. Volcanic islands in the Trobriand Arc (for example, Woodlark Island Amphlett Islands and/or Egum Atoll) are probable sources for several volcaniclastic layers with ages

  16. Optimal likelihood-based matching of volcanic sources and deposits in the Auckland Volcanic Field

    Science.gov (United States)

    Kawabata, Emily; Bebbington, Mark S.; Cronin, Shane J.; Wang, Ting

    2016-09-01

    In monogenetic volcanic fields, where each eruption forms a new volcano, focusing and migration of activity over time is a very real possibility. In order for hazard estimates to reflect future, rather than past, behavior, it is vital to assemble as much reliable age data as possible on past eruptions. Multiple swamp/lake records have been extracted from the Auckland Volcanic Field, underlying the 1.4 million-population city of Auckland. We examine here the problem of matching these dated deposits to the volcanoes that produced them. The simplest issue is separation in time, which is handled by simulating prior volcano age sequences from direct dates where known, thinned via ordering constraints between the volcanoes. The subproblem of varying deposition thicknesses (which may be zero) at five locations of known distance and azimuth is quantified using a statistical attenuation model for the volcanic ash thickness. These elements are combined with other constraints, from widespread fingerprinted ash layers that separate eruptions and time-censoring of the records, into a likelihood that was optimized via linear programming. A second linear program was used to optimize over the Monte-Carlo simulated set of prior age profiles to determine the best overall match and consequent volcano age assignments. Considering all 20 matches, and the multiple factors of age, direction, and size/distance simultaneously, results in some non-intuitive assignments which would not be produced by single factor analyses. Compared with earlier work, the results provide better age control on a number of smaller centers such as Little Rangitoto, Otuataua, Taylors Hill, Wiri Mountain, Green Hill, Otara Hill, Hampton Park and Mt Cambria. Spatio-temporal hazard estimates are updated on the basis of the new ordering, which suggest that the scale of the 'flare-up' around 30 ka, while still highly significant, was less than previously thought.

  17. Sulfur K-edge XANES study of S sorbed onto volcanic ashes

    Energy Technology Data Exchange (ETDEWEB)

    Farges, F; Keppler, H [Bayerische Geoinsitut, Universitaet Bayreuth, Bayreuth (Germany); Flank, A-M; Lagarde, P, E-mail: farges@mnhn.f [CNRS UR1 Synchrotron Soleil, BP 48, 91192 Gif sur Yvette (France)

    2009-11-15

    Powders of four synthetic glasses of volcanic composition, a silica glass and crystalline quartz were equilibrated with SO{sub 2} to study the speciation of S sorbed onto their surface. These samples mimic the aerosols injected into the atmosphere during volcanic eruptions. Volcanic sulfur is known to globally affect the Earth's climate with an opposite effect to CO{sub 2}. However, absorption on ashes may reduce the amount of sulfur entering the stratosphere. S K-edge micro-XANES ({mu}XANES) spectra and {mu}XRF maps were collected at the LUCIA beamline (SOLEIL) at the SLS (Switzerland). When photoreduction is minimized, SO{sub 2} is sorbed mostly as sulfates moieties. The sorption of S is controlled by the surface structure of the powders probed. Presence of defects, non-bridging oxygens and network-modifiers (alkali and alkali-earths) enhance S-sorption as sulfate moieties onto the powders surface. Therefore, the quantity of S released to the atmosphere is highly dependant on the type of ash produced during eruptions that help to better model the climatic impact of volcanic S.

  18. Electrochemical sensor monitoring of volcanic gases

    Science.gov (United States)

    Roberts, Tjarda; Freshwater, Ray; Oppenheimer, Clive; Saffell, John; Jones, Rod; Griffiths, Paul; Braban, Christine; Mead, Iqbal

    2010-05-01

    Advances in instrumentation have fuelled a recent growth of interest in using portable sensor systems for environmental monitoring of pollution. Developments in wireless technology are enabling such systems to operate remotely and autonomously, generating a wealth of environmental data. We report here on the application of miniature Alphasense electrochemical sensors to the detection and characterisation of gases in volcanic plumes. A highly portable sensor system was developed to operate an array of 6 low cost electrochemical sensors to detect CO, H2, HCl, SO2, H2S and NO2 at 1 Hz. A miniature pump draws air over all sensors simultaneously (i.e. sensors arranged in parallel). The sensor output in these campaigns was logged on PDAs for real-time viewing, and later download (with a view to future data-streaming). The instrument was deployed at a number of volcanoes and was subject to extremely harsh conditions including highly acidic environments, low (Antarctic) temperatures, and transport over rough terrain. Analysis methods are demonstrated that consider calibration, cross-sensitivities of the sensors to multiple gases, differing sensor response times, temperature dependence, and background sensor drift with time. The analysis is applied to a range of plume field-measurements to extract gas concentrations ranging from 100's ppmv to sub-ppmv and to characterise the individual volcano emissions. Applications of similar sensor systems for real-time long-term monitoring of volcanic emissions (which may indicate and ultimately predict eruptive behavior), and UAV and balloon-borne plume sampling are now already being realised. This work focused on demonstrating the application of electrochemical sensors to monitoring of environmental pollution from volcanoes. Other applications for similar sensors include the near-source monitoring of industrial emissions, and of pollutant levels enhanced by traffic emissions in the urban environment.

  19. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  20. Multiple Glass Ceilings

    OpenAIRE

    Russo, Giovanni; Hassink, Wolter

    2011-01-01

    Both vertical (between job levels) and horizontal (within job levels) mobility can be sources of wage growth. We find that the glass ceiling operates at both margins. The unexplained part of the wage gap grows across job levels (glass ceiling at the vertical margin) and across the deciles of the intra-job-level wage distribution (glass ceiling at the horizontal margin). This implies that women face many glass ceilings, one for each job level above the second, and that the glass ceiling is a p...

  1. Source mechanisms of volcanic tsunamis.

    Science.gov (United States)

    Paris, Raphaël

    2015-10-28

    Volcanic tsunamis are generated by a variety of mechanisms, including volcano-tectonic earthquakes, slope instabilities, pyroclastic flows, underwater explosions, shock waves and caldera collapse. In this review, we focus on the lessons that can be learnt from past events and address the influence of parameters such as volume flux of mass flows, explosion energy or duration of caldera collapse on tsunami generation. The diversity of waves in terms of amplitude, period, form, dispersion, etc. poses difficulties for integration and harmonization of sources to be used for numerical models and probabilistic tsunami hazard maps. In many cases, monitoring and warning of volcanic tsunamis remain challenging (further technical and scientific developments being necessary) and must be coupled with policies of population preparedness. © 2015 The Author(s).

  2. Anomalous diffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi

    2015-01-01

    Volcanic seismicity at Mt. Etna is studied. It is found that the associated stochastic process exhibits a subdiffusive phenomenon. The jump probability distribution well obeys an exponential law, whereas the waiting-time distribution follows a power law in a wide range. Although these results would seem to suggest that the phenomenon could be described by temporally-fractional kinetic theory based on the viewpoint of continuous-time random walks, the exponent of the power-law waiting-time distribution actually lies outside of the range allowed in the theory. In addition, there exists the aging phenomenon in the event-time averaged mean squared displacement, in contrast to the picture of fractional Brownian motion. Comments are also made on possible relevances of random walks on fractals as well as nonlinear kinetics. Thus, problems of volcanic seismicity are highly challenging for science of complex systems.

  3. Volcanic ash cloud detection from MODIS image based on CPIWS method

    Science.gov (United States)

    Liu, Lan; Li, Chengfan; Lei, Yongmei; Yin, Jingyuan; Zhao, Junjuan

    2017-02-01

    Volcanic ash cloud detection has been a difficult problem in moderate-resolution imaging spectroradiometer (MODIS) multispectral remote sensing application. Principal component analysis (PCA) and independent component analysis (ICA) are effective feature extraction methods based on second-order and higher order statistical analysis, and the support vector machine (SVM) can realize the nonlinear classification in low-dimensional space. Based on the characteristics of MODIS multispectral remote sensing image, via presenting a new volcanic ash cloud detection method, named combined PCA-ICA-weighted and SVM (CPIWS), the current study tested the real volcanic ash cloud detection cases, i.e., Sangeang Api volcanic ash cloud of 30 May 2014. Our experiments suggest that the overall accuracy and Kappa coefficient of the proposed CPIWS method reach 87.20 and 0.7958%, respectively, under certain conditions with the suitable weighted values; this has certain feasibility and practical significance.

  4. Two-Level Solutions to Exponentially Complex Problems in Glass Science

    DEFF Research Database (Denmark)

    Mauro, John C.; Smedskjær, Morten Mattrup

    Glass poses an especially challenging problem for physicists. The key to making progress in theoretical glass science is to extract the key physics governing properties of practical interest. In this spirit, we discuss several two-level solutions to exponentially complex problems in glass science...

  5. Volcanic mercury in Pinus canariensis

    Science.gov (United States)

    Rodríguez Martín, José Antonio; Nanos, Nikos; Miranda, José Carlos; Carbonell, Gregoria; Gil, Luis

    2013-08-01

    Mercury (Hg) is a toxic element that is emitted to the atmosphere by both human activities and natural processes. Volcanic emissions are considered a natural source of mercury in the environment. In some cases, tree ring records taken close to volcanoes and their relation to volcanic activity over time are contradictory. In 1949, the Hoyo Negro volcano (La Palma-Canary Islands) produced significant pyroclastic flows that damaged the nearby stand of Pinus canariensis. Recently, 60 years after the eruption, we assessed mercury concentrations in the stem of a pine which survived volcano formation, located at a distance of 50 m from the crater. We show that Hg content in a wound caused by pyroclastic impacts (22.3 μg kg-1) is an order of magnitude higher than the Hg concentrations measured in the xylem before and after the eruption (2.3 μg kg-1). Thus, mercury emissions originating from the eruption remained only as a mark—in pyroclastic wounds—and can be considered a sporadic and very high mercury input that did not affect the overall Hg input in the xylem. In addition, mercury contents recorded in the phloem (9.5 μg kg-1) and bark (6.0 μg kg-1) suggest that mercury shifts towards non-living tissues of the pine, an aspect that can be related to detoxification in volcanism-adapted species.

  6. Submarine volcanoes along the Aegean volcanic arc

    Science.gov (United States)

    Nomikou, Paraskevi; Papanikolaou, Dimitrios; Alexandri, Matina; Sakellariou, Dimitris; Rousakis, Grigoris

    2013-06-01

    The Aegean volcanic arc has been investigated along its offshore areas and several submarine volcanic outcrops have been discovered in the last 25 years of research. The basic data including swath bathymetric maps, air-gun profiles, underwater photos and samples analysis have been presented along the four main volcanic groups of the arc. The description concerns: (i) Paphsanias submarine volcano in the Methana group, (ii) three volcanic domes to the east of Antimilos Volcano and hydrothermal activity in southeast Milos in the Milos group, (iii) three volcanic domes east of Christiana and a chain of about twenty volcanic domes and craters in the Kolumbo zone northeast of Santorini in the Santorini group and (iv) several volcanic domes and a volcanic caldera together with very deep slopes of several volcanic islands in the Nisyros group. The tectonic structure of the volcanic centers is described and related to the geometry of the arc and the neotectonic graben structures that usually host them. The NE-SW direction is dominant in the Santorini and Nisyros volcanic groups, located at the eastern part of the arc, where strike-slip is also present, whereas NW-SE direction dominates in Milos and Methana at the western part, where co-existence of E-W disrupting normal faults is observed. The volcanic relief reaches 1100-1200 m in most cases. This is produced from the outcrops of the volcanic centers emerging usually at 400-600 m depth and ending either below sea level or at high altitudes of 600-700 m on the islands. Hydrothermal activity at relatively high temperatures observed in Kolumbo is remarkable whereas low temperature phenomena have been detected in the Santorini caldera around Kameni islands and in the area southeast of Milos. In Methana and Nisyros, hydrothermal activity seems to be limited in the coastal areas without other offshore manifestations.

  7. The plutonic-volcanic connection: are we even on the right track? (Invited)

    Science.gov (United States)

    Lundstrom, C.; Chakraborty, P.; Zambardi, T.

    2013-12-01

    The connection between silicic volcanic and plutonic rocks is full of contradictions. Foremost, granitic plutons reflect long slow incremental emplacement yet vast amounts of aphyric ignimbrite can be erupted rapidly. Heat flow, geophysical tomography, geochronology, geochemistry and petrology all provide observations, yet we are far from any consensus. The two most popular suggestions for forming ignimbrites, extraction of partial melt from a granitic upper crust reservoir or lower crustal hot zone melting, are each inconsistent with some observations/constraints. 100% melting of a granite mush, which may be consistent with many observations, was previously proposed1 but dismissed due to the large amount of latent heat needed to completely melt a mush. This work first presents new non-traditional isotope ratio data (Fe, Si) for plutonic and volcanic rocks suites showing that like Harker diagrams, volcanics and plutonics produce identical systematic behavior with differentiation. δ56Fe forms upwardly curving trends with increasing silica whereas δ30Si increases linearly. The logical deduction is that volcanics reflect 100% mobilization of a granite mush (not necessarily melting). While the origin of NTSI variations remains debated, the systematic NTSI trends are consistent with prediction of a top-down thermal migration zone refining (TMZR) process2. In part 2, we assume TMZR generates a granitic mush and propose that an instability in this mush leads to a runaway effect that results in eruption of aphyric ignimbrite. Experiments show that wet andesite evolves to granite at the cold (400°C) end of a thermal gradient3 with hydrous peralkaline melt existing interstitially. Previous work4 shows that such melts show retrograde immiscibility, segregating into a water rich melt and a water poor melt with temperature increase. Thus, as the mush builds down into hot crust, it crosses the immiscibility boundary triggering release of the water-rich phase; buoyant rise and

  8. Glass and glass-ceramic photonic systems

    Science.gov (United States)

    Zur, Lidia; Thi Ngoc Tran, Lam; Meneghetti, Marcello; Varas, Stefano; Armellini, Cristina; Ristic, Davor; Chiasera, Alessandro; Scotognella, Francesco; Pelli, Stefano; Nunzi Conti, Gualtiero; Boulard, Brigitte; Zonta, Daniele; Dorosz, Dominik; Lukowiak, Anna; Righini, Giancarlo C.; Ramponi, Roberta; Ferrari, Maurizio

    2017-02-01

    The development of optically confined structure is a major topic in both basic and applied physics not solely ICT oriented but also concerning lighting, laser, sensing, energy, environment, biological and medical sciences, and quantum optics. Glasses and glass-ceramics activated by rare earth ions are the bricks of such structures. Glass-ceramics are nanocomposite systems that exhibit specific morphologic, structural and spectroscopic properties allowing developing new physical concepts, for instance the mechanism related to the transparency, as well as novel photonic devices based on the enhancement of the luminescence. The dependence of the final product on the specific parent glass and on the fabrication protocol still remain an important task of the research in material science. Looking to application, the enhanced spectroscopic properties typical of glass ceramic in respect to those of the amorphous structures constitute an important point for the development of integrated optics devices, including optical amplifiers, monolithic waveguide laser, novel sensors, coating of spherical microresonators, and up and down converters. This paper presents some results obtained by our consortium regarding glass-based photonics systems. We will comment the energy transfer mechanism in transparent glass ceramics taking as examples the up and down conversion systems and the role of SnO2 nanocrystals as sensitizers. Coating of spherical resonators by glass ceramics, 1D-Photonic Crystals for luminescence enhancement, laser action and disordered 1-D photonic structures will be also discussed. Finally, RF-Sputtered rare earth doped P2O5- SiO2-Al2O3-Na2O-Er2O3 planar waveguides, will be presented.

  9. Combining observations and model simulations to reduce the hazard of Etna volcanic ash plumes

    Science.gov (United States)

    Scollo, Simona; Boselli, Antonella; Coltelli, Mauro; Leto, Giuseppe; Pisani, Gianluca; Prestifilippo, Michele; Spinelli, Nicola; Wang, Xuan; Zanmar Sanchez, Ricardo

    2014-05-01

    Etna is one of the most active volcanoes in the world with a recent activity characterized by powerful lava fountains that produce several kilometres high eruption columns and disperse volcanic ash in the atmosphere. It is well known that, to improve the volcanic ash dispersal forecast of an ongoing explosive eruption, input parameters used by volcanic ash dispersal models should be measured during the eruption. In this work, in order to better quantify the volcanic ash dispersal, we use data from the video-surveillance system of Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, and from the lidar system together with a volcanic ash dispersal model. In detail, the visible camera installed in Catania, 27 km from the vent is able to evaluate the evolution of column height with time. The Lidar, installed at the "M.G. Fracastoro" astrophysical observatory (14.97° E, 37.69° N) of the Istituto Nazionale di Astrofisica in Catania, located at a distance of 7 km from the Etna summit craters, uses a frequency doubled Nd:YAG laser source operating at a 532-nm wavelength, with a repetition rate of 1 kHz. Backscattering and depolarization values measured by the Lidar system can give, with a certain degree of uncertainty, an estimation of volcanic ash concentration in atmosphere. The 12 August 2011 activity is considered a perfect test case because volcanic plume was retrieved by both camera and Lidar. We evaluated the mass eruption rate from the column height and used best fit procedures comparing simulated volcanic ash concentrations with those extracted by the Lidar data. During this event, powerful lava fountains were well visible at about 08:30 GMT and a sustained eruption column was produced since about 08:55 GMT. Ash emission completely ceased around 11:30 GMT. The proposed approach is an attempt to produce more robust ash dispersal forecasts reducing the hazard to air traffic during Etna volcanic crisis.

  10. Ambient Noise Surface Wave Tomography of the volcanic systems of eastern Iceland

    Science.gov (United States)

    Green, R. G.; Priestley, K. F.; White, R. S.

    2015-12-01

    The Vatnajökull region of central-east Iceland lies above the head of the Iceland mantle plume where the crust is thickest due to enhanced melt supply. As a result the region contains a high density of volcanic rift systems, with six large subglacial central volcanoes. Due to the ice cover, the geological structure of the area and the location of past eruptions are poorly known. Imaging of the crustal velocity heterogeneities beneath the ice sheet aims to reveal much in terms of the structure of these volcanic plumbing systems. Mapping of significant velocity changes through time may also be indicative of movement of melt around the central volcanoes; one of which (Bárðarbunga) experienced a major rifting event in August 2014 (Sigmundsson et al. Nature 2015, Green et al. Nature Geosci. 2015). We present results from tomographic imaging of the volcanic systems in the region, using continuous data from a local broadband seismic network in central-east Iceland which provides excellent ray path coverage of the volcanic systems. This is supplemented by data from the HOTSPOT and ICEMELT experiments and the permanent monitoring stations of the Icelandic Meteorological Office. We process the continuous data following Benson et al. 2007 and automatic frequency-time analysis (FTAN) routines are used to extract more than 9000 dispersion measurements. We then generate Rayleigh wave group velocity maps which we present here. We find low velocity regions beneath the Vatnajökull icecap which are bounded by the surface expression of the volcanic rift systems. The lower velocities also extend north-west to the volcanic system under the Hofsjökull ice cap, and northwards towards Askja and the volcanic systems of the northern volcanic zone. We also produce locations and focal mechanisms of earthquakes caused by magmatic and hydrothermal activity to correlate structure with the activity of the volcanic systems.

  11. Geology and Geochronology of the Central Part of Chiapanecan Volcanic Arc, Mexico.

    Science.gov (United States)

    Layer, P. W.

    2006-12-01

    The Chiapanecan Volcanic Arc (CVA) is a 150 km stretch of volcanoes irregularly aligned in a northwest direction, including El Chichón volcano located in the central portion of the State of Chiapas, southern Mexico. It lies between two great volcanic features: the Trans-Mexican Volcanic Arc to the northwest, and the Central American Volcanic Arc to the southeast, in a complex zone of the interaction of the North American, Caribbean and Cocos Plates. The central part of the CVA is composed of an irregular northwest alignment of at least 12 volcanic structures located 80 km to the southeast of El Chichón (the only currently active volcano in the CVA). These structures include one explosion crater (Navenchauc), one collapse structure (Apas), one dome complex (Tzontehuitz) and nine volcanic domes (Navenchauc, Huitepec, Amahuitz, La Iglesia, Mispía, La Lanza, Venustiano Carranza, Miguel Hidalgo and Santotón) with associated pyroclastic flow deposits. The juvenile lithics from these deposits have a porphyritic texture with phenocrysts of plagioclase (±), amphibole (±), clinopyroxene (±), orthopyroxene (±) and Fe-Ti oxides surrounded by a matrix composed by microlites of plagioclase and glass. The chemical results obtained from representative samples from the deposits and structures indicate that these belong to the series of subalkaline rocks, and fall into the calcalkaline field with medium to high contents of potassium. They vary in their composition from andesite to dacite with an interval of silica between a 56 to a 66% (wt.). The ages reported in the literature and obtained in this study by means of the K-Ar and the 40Ar/39Ar methods, respectively, indicated that volcanism was episodic and spanned a time from 2100 ky ago (Tzontehuitz) to 225 ky ago (Venustiano Carranza).

  12. Ondas ultrassônicas e pérolas de vidro: um novo método de extração de beta-galactosidase para uso em laboratório Ultrasonic waves and glass pearls: a new method of extraction of beta-galactosodade for use in laboratory

    Directory of Open Access Journals (Sweden)

    Fabiana Oliveira de Medeiros

    2008-01-01

    Full Text Available The optimization of a traditional technique of cellular disruption by abrasion was carried out and a process using ultrasonic waves associated with glass pearls to extract beta-galactosidase from Kluyveromyces marxianus proposed. In the first case, the effects of the diameter and weight of the pearls in relation to the volume of cellular suspension and amount of time for cellular disruption were evaluated. The efficiency of the new process of cellular disruption was evaluated by varying the length of time of sonification and comparing with the method of abrasion under the same conditions. The proposed method can be efficiently applied to obtain beta-galactosidase at laboratory scale.

  13. Liquid Glass: A Facile Soft Replication Method for Structuring Glass.

    Science.gov (United States)

    Kotz, Frederik; Plewa, Klaus; Bauer, Werner; Schneider, Norbert; Keller, Nico; Nargang, Tobias; Helmer, Dorothea; Sachsenheimer, Kai; Schäfer, Michael; Worgull, Matthias; Greiner, Christian; Richter, Christiane; Rapp, Bastian E

    2016-06-01

    Liquid glass is a photocurable amorphous silica nanocomposite that can be structured using soft replication molds and turned into glass via thermal debinding and sintering. Simple polymer bonding techniques allow the fabrication of complex microsystems in glass like microfluidic chips. Liquid glass is a step toward prototyping of glass microstructures at low cost without requiring cleanroom facilities or hazardous chemicals.

  14. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    The use of glass as a load carrying material in structural elements is rarely seen even though glass is a popular material for many architects. This is owed to the unreliable and low tensile strength, which is due to surface flaws and high brittleness of the material. These properties lead...... to breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  15. Radiation effects in glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ehrt, D.; Vogel, W. (Otto-Schott-Inst., Chemische Fakultaet, Friedrich-Schiller-Univ., Jena (Germany))

    1992-03-01

    Glass was produced by man about 4000 years ago. The scientific exploration of glass is very young and closely connected with Jena. Fraunhofer, Goethe, Dobereiner, Abbe, Zeiss and Schott are famous names on this field. Both crystals and glasses are solids. However, there are fundamental differences in their properties and behavior. Glass is a thermodynamically unstable state and has a defect structure compared to the crystal. Glass and its properties are subject to a variety of changes under the influence of high energy radiation. In general, effects extend from the reduction of specific ions to the collapse of the entire network. Ultraviolet and X-ray radiation effects on UV-transmitting glasses will be discussed. (orig.).

  16. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

    Jensen, Martin; Zhang, L.; Keding, Ralf;

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...... the dimension and the intensity is used to quantify and rank the homogeneity of glass products. Compared with the refractive index method, the image processing method has a wider detection range and a lower statistical uncertainty....

  17. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

    Jensen, Martin; Zhang, L.; Keding, Ralf

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...... the dimension and the intensity is used to quantify and rank the homogeneity of glass products. Compared with the refractive index method, the image processing method has a wider detection range and a lower statistical uncertainty....

  18. Raman Spectra of Glasses

    Science.gov (United States)

    1986-11-30

    17), Raman spectra, plus a , . theoretical treatment of the data, f complex fluorozirconate 14 I anions in ZBLAN glasses and melts (16), and...based ZBLAN glasses ) 17. ICORS (International Conference on Raman Spectroscopy) Proceedings, London, England. Conferencf 5-9 Sep 88. (Molten silica...RESEARCH FINAL REPORT DTIC CONTRACT N00014-81-K-0501 &JELECTE 1 MAY 81 -- 30 NOV 86 EJJAN041989 V "RAMAN SPECTRA OF GLASSES " 0 During the five years of the

  19. Diamond turning of glass

    Energy Technology Data Exchange (ETDEWEB)

    Blackley, W.S.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the critical cutting depth concepts for single point diamond turning of brittle, amorphous materials. Inorganic glasses and a brittle, thermoset polymer (organic glass) are the principal candidate materials. Interrupted cutting tests similar to those done in earlier research are Ge and Si crystals will be made to obtain critical depth values as a function of machining parameters. The results will provide systematic data with which to assess machining performance on glasses and amorphous materials

  20. Catastrophic volcanic collapse: relation to hydrothermal processes.

    Science.gov (United States)

    López, D L; Williams, S N

    1993-06-18

    Catastrophic volcanic collapse, without precursory magmatic activity, is characteristic of many volcanic disasters. The extent and locations of hydrothermal discharges at Nevado del Ruiz volcano, Colombia, suggest that at many volcanoes collapse may result from the interactions between hydrothermal fluids and the volcanic edifice. Rock dissolution and hydrothermal mineral alteration, combined with physical triggers such as earth-quakes, can produce volcanic collapse. Hot spring water compositions, residence times, and flow paths through faults were used to model potential collapse at Ruiz. Caldera dimensions, deposits, and alteration mineral volumes are consistent with parameters observed at other volcanoes.

  1. Nephelometric Dropsonde for Volcanic Ash Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes could enable unprecedented observations of...

  2. Metal Halide Optical Glasses.

    Science.gov (United States)

    1988-01-01

    while some of the multi- component "modified" glasses (e.g., ZBLAN ) could easily be cast into pieces several mm thick. 23 The difference between the...energy. 7-1 0 Typical plots pf 24 of log Iqi versus ]/Tf for ZB-I, ZBL, ZBLA, ZBLAN and ZBLALi glasses are presented in Fig. 3. These plots are linear... ZBLAN glasses are more resistant to devitrification than the corresponding ZBLLi or ZBLN glasses , although this does not appear to be manifested in

  3. Thermal vesiculation during volcanic eruptions

    Science.gov (United States)

    Lavallée, Yan; Dingwell, Donald B.; Johnson, Jeffrey B.; Cimarelli, Corrado; Hornby, Adrian J.; Kendrick, Jackie E.; von Aulock, Felix W.; Kennedy, Ben M.; Andrews, Benjamin J.; Wadsworth, Fabian B.; Rhodes, Emma; Chigna, Gustavo

    2015-12-01

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the ‘strength’ of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  4. Volcanic processes on early-forming asteroids.

    Science.gov (United States)

    Wilson, L.; Keil, K.

    2011-12-01

    A variety of meteorite groups represent samples of asteroids that formed while 26Al was still the dominant heat source in Solar System materials. These bodies differentiated to varying degrees beyond the temperature of FeNi-FeS melting, with sufficient silicate melting to allow metal core formation. The silicate melts segregated upward from the interiors to suffer various fates: intrusion at shallow levels, eruption onto the surface, or ejection into space in explosive eruptions in which the eruption speed exceeded the escape speed. These three styles of plutonic/volcanic activity were not mutually exclusive; their relative importance was a function of asteroid size and composition, with the major compositional factor being the total available volatile inventory. Much research has been concerned with whether silicate melts were extracted from the mantle during the period of mantle heating or while the mantle was cooling after reaching its peak temperature and degree of partial melting (a "magma ocean" stage). Traditionally, the relevant arguments have been based on the petrology and geochemistry of the meteorites sampling these bodies. Instead, we focus on the fluid dynamic aspects of eruption and intrusion processes and show how these impose additional limitations on various aspects of the igneous activity. For example, 40% melting of bodies the size of 4 Vesta (~250 km radius) and the Ureilite Parent Body (UPB, ~100 km radius) over the course of a 0.5 Ma heating period represent melt volume production rates of ~350 and 20 cubic meters per second, respectively, in each of what we demonstrate should have been ~4 volcanic provinces on each body. All differentiated asteroids must of necessity have had a surface layer ~10 km thick at sub-solidus temperatures controlled by conductive cooling. To erupt magma at the surface (or intrude magma at very shallow depth) through such a crust would have required the propagation of dikes within which the combination of dike width

  5. Geochemical Characteristics and Metallogenesis of Volcanic Rocks as Exemplified by Volcanic Rocks in Ertix,Xinjiang

    Institute of Scientific and Technical Information of China (English)

    刘铁庚; 叶霖

    1997-01-01

    Volcanic rocks in Ertix,Xinjiang,occurring in the collision zone between the Siberia Plate and the Junggar Plate,are distributed along the Eritix River Valley in northern Xinjiang.The volcanic rocks were dated at Late Paleozoic and can be divided into the spilite-keratophyre series and the basalt-andesite series.The spilite-keratophyre series volcanic rocks occur in the Altay orogenic belt at the southwest margin of the Siberia Plate.In addition to sodic volcanic rocks.There are also associated potassic-sodic volcanic rocks and potassic volcanic rocks.The potassic-sodic volcanic rocks occur at the bottom of the eruption cycle and control the distribution of Pb and Zn deposits.The potassic volcanic rocks occur at the top of the eruption cycle and are associated with Au and Cu mineralizations.The sodic volcanic rocks occur in the middle stage of eruption cycle and control the occurrence of Cu(Zn) deposits.The basalt-andesite series volcanic rocks distributed in the North Junggar orogenic belt at the north margin of the Junggar-Kazakstan Plate belong to the potassic sodic volcain rocks.The volcanic rocks distributed along the Ulungur fault are relatively rich in sodium and poor in potassium and are predominated by Cu mineralization and associated with Au mineralization.Those volcanic rocks distributed along the Ertix fault are relatively rich in K and poor in Na,with Au mineralization being dominant.

  6. Colonisation of freshly deposited volcanic tephra by soil fungi

    Science.gov (United States)

    Tarasenko, Inga; Opfergelt, Sophie; Stenuit, Benoît; Daily, Hélène; Bonneville, Steeve; Müller, Dirk; Delmelle, Pierre

    2016-04-01

    In active volcanic regions, soils are repeatedly exposed to eruption products, notably tephra emissions. Deposition of volcanic tephra on soil may modify water and gas exchanges between the soil surface and the atmosphere. Through chemical weathering, the silicate glass and mineral components of freshly deposited tephra act as a source of bioavailable potassium and phosphorus. In addition, opportunist fungi may be able to enhance access to these elements via physical and biochemical processes. Altogether, tephra deposition has the potential to affect biological activity and hence, nutrient cycling in the buried soil. Here we present the preliminary results of an ongoing investigation aimed at shedding light on the interaction of soil fungi with freshly deposited tephra. The study site (elevation - 1755 m a.s.l.) is a coniferous forest on the northeastern slope of Etna volcano, Sicily, which received about 20 cm of tephra in November 2013. Soil and tephra samples were collected in September 2014 and October 2015. A variety of biological, chemical and mineralogical analyses were carried out to determine fungal biomass, fungi species and tephra weathering stage. Colonisation of the fresh tephra by fungi is evidenced by the high fungal biomass measured in this material. DNA analyses further indicate that these fungi originate from the soil beneath the tephra layer. While chemical weathering of the tephra material has started, there is no clear indication that fungi colonisation is enhancing this process. We will continue to monitor fungi-tephra interaction on Etna during the next few years.

  7. Using Volcanic Ash to Remove Dissolved Uranium and Lead

    Science.gov (United States)

    McKay, David S.; Cuero, Raul G.

    2009-01-01

    Experiments have shown that significant fractions of uranium, lead, and possibly other toxic and/or radioactive substances can be removed from an aqueous solution by simply exposing the solution, at ambient temperature, to a treatment medium that includes weathered volcanic ash from Pu'u Nene, which is a cinder cone on the Island of Hawaii. Heretofore, this specific volcanic ash has been used for an entirely different purpose: simulating the spectral properties of Martian soil. The treatment medium can consist of the volcanic ash alone or in combination with chitosan, which is a natural polymer that can be produced from seafood waste or easily extracted from fungi, some bacteria, and some algae. The medium is harmless to plants and animals and, because of the abundance and natural origin of its ingredient( s), is inexpensive. The medium can be used in a variety of ways and settings: it can be incorporated into water-filtration systems; placed in contact or mixed with water-containing solids (e.g., soils and sludges); immersed in bodies of water (e.g., reservoirs, lakes, rivers, or wells); or placed in and around nuclear power plants, mines, and farm fields.

  8. Mechanical Properties and Solidiifed Mechanism of Tailings Mortar with Waste Glass

    Institute of Scientific and Technical Information of China (English)

    NING Baokuan; XU Jingwen; CHEN Sili

    2015-01-01

    In order to improve the comprehensive utilization of solid waste such as iron tailings and waste glass and so on, mechanical property test of cement tailings mortar mixed waste glass and curing mechanism research were conducted in the key materials mechanics lab of Liaoning province. The experimental results show that adding waste glass particles can improve the grain size distribution of tailings. The effect is proportional to the content. The compressive strength of tailings mortar has increased signiifcantly. The ifneness modulus of tailings mortar mixture adding waste glass powder was gradually reducing with the increase of the dosage of waste glass powder, but the compressive strength of the mixture has gradually enhanced with the increase of the dosage. Microscopic analysis shows that the waste glass particles in the mortar mainly play a role of coarse aggregate and glass powder after grinding fine below a certain size shows strong volcanic activity, which can act hydration with tailings, at the same time glass powder also, plays a role in ifne aggregate iflling. Therefore, all of glass particles and glass powder can be used as the additive material for improving and optimizing the mechanical property of tailings mortar.

  9. Lanthanoides in Glass and Glass Ceramics

    Science.gov (United States)

    Meinhardt, Jürgen; Kilo, Martin; Somorowsky, Ferdinand; Hopp, Werner

    2017-03-01

    Many types of glass contain lanthanoides; among them, special glass for optical applications is the one with the highest content of lanthanoides. The precise determination of the lanthanoides' concentration is performed by inductively coupled plasma-optical emission spectrometry (ICP-OES). However, up to now, there are no established standard processes guaranteeing a uniform approach to the lanthanoide analysis. The knowledge of the lanthanoides' concentrations is necessary on the microscale in some cases, especially if a suitable separation and recycling procedure is to be applied. Here, the analysis is performed by energy-dispersive X-ray (EDX) or wavelength-dispersive X-ray (WDX) analytics in the scanning electron microscope.

  10. Electric glass capturing markets

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, K.; Wikstroem, T.

    1996-11-01

    Electric glass has found its place on the construction market. In public buildings, electrically heatable windows are becoming the leading option for large glass walls. Studies on detached houses, both new and renovated, show that floor heating combined with electrically heatable windowpanes is the best choice with respect to resident`s comfort. (orig.)

  11. lead glass brick

    CERN Multimedia

    As well as accelerators to boost particles up to high energy, physicists need detectors to see what happens when those particles collide. This lead glass block is part of a CERN detector called OPAL. OPAL uses some 12 000 blocks of glass like this to measure particle energies.

  12. Glasses for photonic applications

    NARCIS (Netherlands)

    Richardson, K.; Krol, D.M.; Hirao, K.

    2010-01-01

    Recent advances in the application of glassy materials in planar and fiber-based photonic structures have led to novel devices and components that go beyond the original thinking of the use of glass in the 1960s, when glass fibers were developed for low-loss, optical communication applications. Expl

  13. Getting Started with Glass

    Science.gov (United States)

    White, Heather

    2007-01-01

    The metamorphosis of glass when heated is a magical process to students, yet teachers are often reluctant to try it in class. The biggest challenge in working with glass in the classroom is to simplify procedures just enough to ensure student success while maintaining strict safety practices so no students are injured. Project concepts and safety…

  14. Glass Sword of Damocles

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A string of accidents draws attention to the safety of the gleaming glass-walled skyscrapers, now common in China’s major cities On July 8, as 19-year-old Zhu Yiyi was walking past a 23-story building in Hangzhou, east China’s Zhejiang Province, shards of glass falling

  15. Electric glass capturing markets

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, K.; Wikstroem, T.

    1996-11-01

    Electric glass has found its place on the construction market. In public buildings, electrically heatable windows are becoming the leading option for large glass walls. Studies on detached houses, both new and renovated, show that floor heating combined with electrically heatable windowpanes is the best choice with respect to resident`s comfort. (orig.)

  16. Cenozoic volcanic rocks of Saudi Arabia

    Science.gov (United States)

    Coleman, R.G.; Gregory, R.T.; Brown, G.F.

    2016-01-01

    The Cenozoic volcanic rocks of Saudi Arabia cover about 90,000 km2, one of the largest areas of alkali olivine basalt in the world. These volcanic rocks are in 13 separate fields near the eastern coast of the Red Sea and in the western Arabian Peninsula highlands from Syria southward to the Yemen Arab Republic.

  17. Relationship between earthquake and volcanic eruption inferred from historical records

    Institute of Scientific and Technical Information of China (English)

    陈洪洲; 高峰; 吴雪娟; 孟宪森

    2004-01-01

    A large number of seismic records are discovered for the first time in the historical materials about Wudalianchi volcanic group eruption in 1720~1721, which provides us with abundant volcanic earthquake information. Based on the written records, the relationship between earthquake and volcanic eruption is discussed in the paper. Furthermore it is pointed that earthquake swarm is an important indication of volcanic eruption. Therefore, monitoring volcanic earthquakes is of great significance for forecasting volcanic eruption.

  18. Lakshmi Planum: A distinctive highland volcanic province

    Science.gov (United States)

    Roberts, Kari M.; Head, James W.

    Lakshmi Planum, a broad smooth plain located in western Ishtar Terra and containing two large oval depressions (Colette and Sacajawea), has been interpreted as a highland plain of volcanic origin. Lakshmi is situated 3 to 5 km above the mean planetary radius and is surrounded on all sides by bands of mountains interpreted to be of compressional tectonic origin. Four primary characteristics distinguish Lakshmi from other volcanic regions known on the planet, such as Beta Regio: (1) high altitude, (2) plateau-like nature, (3) the presence of very large, low volcanic constructs with distinctive central calderas, and (4) its compressional tectonic surroundings. Building on the previous work of Pronin, the objective is to establish the detailed nature of the volcanic deposits on Lakshmi, interpret eruption styles and conditions, sketch out an eruption history, and determine the relationship between volcanism and the tectonic environment of the region.

  19. Defense HLW Glass Degradation Model

    Energy Technology Data Exchange (ETDEWEB)

    D. Strachan

    2004-10-20

    The purpose of this report is to document the development of a model for calculating the release rate for radionuclides and other key elements from high-level radioactive waste (HLW) glasses under exposure conditions relevant to the performance of the repository. Several glass compositions are planned for the repository, some of which have yet to be identified (i.e., glasses from Hanford and Idaho National Engineering and Environmental Laboratory). The mechanism for glass dissolution is the same for these glasses and the glasses yet to be developed for the disposal of DOE wastes. All of these glasses will be of a quality consistent with the glasses used to develop this report.

  20. Geomorphological Approach for Regional Zoning In The Merapi Volcanic Area

    Directory of Open Access Journals (Sweden)

    Langgeng Wahyu Santosa

    2013-07-01

    Full Text Available Geomorphologial approach can be used as the basic for identifying and analyzing the natural resources potentials, especially in volcanic landscape. Based on its geomorphology, Merapi volcanic landscape can be divided into 5 morphological units, i.e.: volcanic cone, volcanic slope, volcanic foot, volcanic foot plain, and fluvio-volcanic plain. Each of these morphological units has specific characteristic and natural resources potential. Based on the condition of geomorphology, the regional zoning can be compiled to support the land use planning and to maintain the conservation of environmental function in the Merapi Volcanic area.

  1. Volcanism and associated hazards: the Andean perspective

    Science.gov (United States)

    Tilling, R. I.

    2009-12-01

    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.

  2. Volcanism and associated hazards: The Andean perspective

    Science.gov (United States)

    Tilling, R.I.

    2009-01-01

    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.

  3. Numerical modeling of volcanic arc development

    Science.gov (United States)

    Gerya, T.; Gorczyk, W.; Nikolaeva, K.

    2007-05-01

    We have created a new coupled geochemical-petrological-thermomechanical numerical model of subduction associated with volcanic arc development. The model includes spontaneous slab bending, subducted crust dehydration, aqueous fluid transport, mantle wedge melting and melt extraction resulting in crustal growth. Two major volcanic arc settings are modeled so far: active continental margins, and intraoceanic subduction. In case of Pacific-type continental margin two fundamentally different regimes of melt productivity are observed in numerical experiments which are in line with natural observations: (1) During continuous convergence with coupled plates highest amounts of melts are formed immediately after the initiation of subduction and then decrease rapidly with time due to the steepening of the slab inclination angle precluding formation of partially molten mantle wedge plumes; (2) During subduction associated with slab delamination and trench retreat resulting in the formation of a pronounced back arc basin with a spreading center in the middle melt production increases with time due to shallowing/stabilization of slab inclination associated with upward asthenospheric mantle flow toward the extension region facilitating propagation of hydrous partially molten plumes from the slab. In case of spontaneous nucleation of retreating oceanic subduction two scenarios of tecono-magmatic evolution are distinguished: (1) decay and, ultimately, the cessation of subduction and related magmatic activity, (2) increase in subduction rate (to up to ~12 cm/yr) and stabilization of subduction and magmatic arc growth. In the first case the duration of subduction correlates positively with the intensity of melt extraction: the period of continued subduction increases from 15,4 Myrs to 47,6 Myrs with the increase of melt extraction threshold from 1% to 9%. In scenario (1) the magmatic arc crust includes large amounts of rocks formed by melting of subducted crust atop the thermally

  4. Volcanic Ashes Intercalated with Cultural Vestiges at Archaeological Sites from the Piedmont to the Amazon, Ecuador

    Science.gov (United States)

    Valverde, Viviana; Mothes, Patricia; Andrade, Daniel

    2014-05-01

    A mineralogical analysis was done on 70 volcanic ashes; 9 corresponding to proximal samples of seven volcanoes: Cotopaxi (4500 yBP), Guagua Pichincha (3300 yBP, 1000 yBP and 1660 yAD), Cuicocha (3100 yBP), Pululahua (2400 yBP), Ninahuilca (2350 yBP and 4600 yBP) and 61 to distal ashes collected at eight archaeological sites in the Coastal, Sierra and Amazon regions of Ecuador. Cultural vestiges are from Pre-ceramic, Formative, Regional Development and Integration periods, with the exception of a site denominated Hacienda Malqui, which also has Inca vestiges. The sampling process was done in collaboration with various archaeologists in 2011-2013. The volcanic ashes were washed, dried and divided in order to obtain a representative fraction and their later analysis with binocular microscope. The microscope analysis allowed determination of the characteristics of each component of volcanic ash. These main elements are: pumice fragments, minerals, volcanic glass, lithics and exogenous material (non volcanic). The petrographic analysis of distal volcanic ash layers at each archaeological site was correlated by their components and characteristics with proximal volcanic ashes of source volcanoes. Some correlations permitted obtaining a relative age for the layers of distal volcanic ash in the archaeological sites. The petrographic analysis showed a correlation between the archaeological sites of Las Mercedes - Los Naranjos, Rumipamba and El Condado (located west of Quito) with the eruptive activity of Guagua Pichincha volcano (3300 yBP, 1000 yBP and 1660 yAD) and Pululahua volcano (2400 yBP). Also, a correlation with eruptive activity of Ninahuilca (2350 yBP), Cotopaxi (4500 yBP) and Quilotoa (800 yBP) volcanoes at Hda. Malqui (60 km west of Latacunga) was provided by mineralogy of the respective ashes expulsed by these volcanoes. The ash layers at Cuyuja (50 km east of Quito) are mostly superficial; they are associated with Quilotoa's 800 yBP plinian. Finally at the

  5. Thermal Conductivity of Foam Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used...... as thermal insulating material in building and chemical industry. The large volume of gas (porosity 90 – 95%) is the main reason of the low thermal conductivity of the foam glass. If gases with lower thermal conductivity compared to air are entrapped in the glass melt, the derived foam glass will contain...... only closed pores and its overall thermal conductivity will be much lower than that of the foam glass with open pores. In this work we have prepared foam glass using different types of recycled glasses and different kinds of foaming agents. This enabled the formation of foam glasses having gas cells...

  6. Complex explosive volcanic activity on the Moon within Oppenheimer crater

    Science.gov (United States)

    Bennett, Kristen A.; Horgan, Briony H. N.; Gaddis, Lisa R.; Greenhagen, Benjamin T.; Allen, Carlton C.; Hayne, Paul O.; Bell, James F.; Paige, David A.

    2016-07-01

    Oppenheimer crater is a floor-fractured crater located within the South Pole-Aitken basin on the Moon, and exhibits more than a dozen localized pyroclastic deposits associated with the fractures. Localized pyroclastic volcanism on the Moon is thought to form as a result of intermittently explosive Vulcanian eruptions under low effusion rates, in contrast to the higher-effusion rate, Hawaiian-style fire fountaining inferred to form larger regional deposits. We use Lunar Reconnaissance Orbiter Camera images and Diviner Radiometer mid-infrared data, Chandrayaan-1 orbiter Moon Mineralogy Mapper near-infrared spectra, and Clementine orbiter Ultraviolet/visible camera images to test the hypothesis that the pyroclastic deposits in Oppenheimer crater were emplaced via Vulcanian activity by constraining their composition and mineralogy. Mineralogically, we find that the deposits are variable mixtures of orthopyroxene and minor clinopyroxene sourced from the crater floor, juvenile clinopyroxene, and juvenile iron-rich glass, and that the mineralogy of the pyroclastics varies both across the Oppenheimer deposits as a whole and within individual deposits. We observe similar variability in the inferred iron content of pyroclastic glasses, and note in particular that the northwest deposit, associated with Oppenheimer U crater, contains the most iron-rich volcanic glass thus far identified on the Moon, which could be a useful future resource. We propose that this variability in mineralogy indicates variability in eruption style, and that it cannot be explained by a simple Vulcanian eruption. A Vulcanian eruption should cause significant country rock to be incorporated into the pyroclastic deposit; however, large areas within many of the deposits exhibit spectra consistent with high abundances of juvenile phases and very little floor material. Thus, we propose that at least the most recent portion of these deposits must have erupted via a Strombolian or more continuous fire

  7. Bioactive glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    de Aza, P. N.

    2007-04-01

    Full Text Available Since the late 1960´s, a great interest in the use of bioceramic materials for biomedical applications has been developed. In a previous paper, the authors reviewed crystalline bioceramic materials “sensus stricto”, it is to say, those ceramic materials, constituted for non-metallic inorganic compounds, crystallines and consolidates by thermal treatment of powders at high temperature. In the present review, the authors deal with those called bioactive glasses and glassceramics. Although all of them are also obtained by thermal treatment at high temperature, the first are amorphous and the second are obtained by devitrification of a glass, although the vitreous phase normally prevails on the crystalline phases. After an introduction to the concept of bioactive materials, a short historical review of the bioactive glasses development is made. Its preparation, reactivity in physiological media, mechanism of bonding to living tissues and mechanical strength of the bone-implant interface is also reported. Next, the concept of glass-ceramic and the way of its preparation are exposed. The composition, physicochemical properties and biological behaviour of the principal types of bioactive glasses and glass-ceramic materials: Bioglass®, Ceravital®, Cerabone®, Ilmaplant® and Bioverit® are also reviewed. Finally, a short review on the bioactive-glass coatings and bioactive-composites and most common uses of bioactive-glasses and glass-ceramics are carried out too.

    Desde finales de los años sesenta, se ha despertado un gran interés por el uso de los materiales biocerámicos para aplicaciones biomédicas. En un trabajo previo, los autores hicieron una revisión de los denominados materiales biocerámicos cristalinos en sentido estricto, es decir, de aquellos materiales, constituidos por compuestos inorgánicos no metálicos, cristalinos y consolidados mediante tratamientos térmicos a altas temperaturas. En el presente trabajo, los autores

  8. Contributions of vitreous natural analogs to the investigation of long-term nuclear glass behavior; Apports des analogues naturels vitreux a la validation des codes de prediction du comportement a long terme des verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Techer, I

    1999-07-01

    This study assesses the extend of the analogy between the alteration behavior in water and in a moist clay environment of aluminosilicate volcanic glass and alumino-borosilicate nuclear containment glass. Basaltic glass alteration in water initially occurs by hydrolysis processes with an activation energy on the order of 73 kJ.mol{sup -1}. As the reaction progresses, the alteration rate drops by over four orders of magnitude from the initial rate r{sub 0}, The alteration kinetics are not governed by the alteration solution chemistry alone, the glass alteration film appears to have a major role as a diffusion barrier limiting the transfer of reaction species and products. All these aspects highlight the behavioral analogy between basaltic glass and nuclear borosilicate glass in aqueous media. Conversely, the alteration reaction of obsidian-type volcanic glass involves other mechanisms than those governing the dissolution of borosilicate glass. Basaltic glass alteration is also examined in the presence of a clay environmental material, in a study of the natural basaltic glass and argillaceous pelites system of the Salagou basin in southern France, in an approach combining mineralogical, chemical and isotopic data to assess the interactions between a basaltic glass and the argillaceous pelites. Laboratory leach test results with basaltic glass and measured data for the Salagou glass in its natural environment are modeled using a code implementing a kinetic law coupling diffusive transfer of dissolved silica with a reaction affinity law. (author)

  9. Sedimentation architecture of the volcanically-dammed Alf valley in the West Eifel Volcanic Field, Germany

    Science.gov (United States)

    Eichhorn, Luise; Lange, Thomas; Engelhardt, Jörn; Polom, Ulrich; Pirrung, Michael; Büchel, Georg

    2015-04-01

    In the southeastern part of the Quaternary West Eifel Volcanic Field, the Alf valley with its morphologically wide (~ 500 m) and flat valley bottom is visibly outstanding. This flat valley bottom was formed during the Marine Isotope Stage 2 due to fluviolacustrine sediments which deposited upstream of a natural volcanic dam. The dam consisted of lava and scoria breccia from the Wartgesberg Volcano complex (Cipa 1958, Hemfler et al. 1991) that erupted ~ 31 BP (40Ar/ 39Ar dating on glass shards, Mertz, pers. communication 2014). Due to this impoundment, the Alf creek turned into a dendritic lake, trapping the catchment sediments. The overall aim is to create the sedimentation architecture of the Alf valley. In comparison to maar archives like Holzmaar or Meerfelder Maar in the vicinity, the fluviolacustrine sediments of the Alf valley show clay-silt lamination despite the water percolation. This archive covers the transition from the Last Glacial Maximum to Early Holocene (Pirrung et al. 2007). Focus of this study is the creation of a 3D model by applying the program ESRI ArcGIS 10.2 to reconstruct the pre-volcanic Alf valley. Moreover, the sedimentation architecture is reconstructed and the sediment fill quantified. Therefore, the digital elevation model with 5 m resolution from the State Survey and Geobasis Information of Rhineland-Palatinate, polreduced magnetic data measured on top of the Strohn lava stream, shear seismic data and core stratigraphies were utilized. Summarizing previous results, Lake Alf had a catchment area of ~ 55 km² (Meerfelder Maar: 1.27 km²) and a surface area of 8.2 km² (Meerfelder Maar: 0.24 km²) considering a maximum lake water level of 410 m a.s.l.. In the deepest parts (~ 50 m) of Lake Alf, lake sediments are laminated, up to 21 m thick and show a very high sedimentation rate ~ 3 mm a-1 (Dehner Maar ~ 1.5 mm a-1, (Sirocko et al. 2013)). The sediments become coarser upstream und stratigraphically above the fine-grained lake sediments

  10. Mapping the topography and cone morphology of the Dalinor volcanic swarm in Inner Mongolia with remote sensing and DEM data

    Science.gov (United States)

    Gong, Liwen; Li, Ni; Fan, Qicheng; Zhao, Yongwei; Zhang, Liuyi; Zhang, Chuanjie

    2016-09-01

    The Dalinor volcanic swarm, located south of Xilinhot, Inner Mongolia of China, was a result of multistage eruptions that occurred since the Neogene period. This swarm is mainly composed of volcanic cones and lava tablelands. The objective of this study is to map the topography and morphology of this volcanic swarm. It is based on a variety of data collected from various sources, such as the digital elevation model (DEM), Landsat images, and a 1:50,000 topographic map, in addition to various software platforms, including ArcGIS, Envi4.8, Global Mapper, and Google Earth for data processing and interpretation. The results show that the overall topography of the volcanic swarm is a platform with a central swell having great undulation, sizable gradient variations, a rough surface, and small terrain relief. According to the undulating characteristics of the line profile, the volcanic swarm can be divided into four stairs with heights of 1,280 m, 1,360 m, 1,440 m, and 1,500 m. The analysis of the swath profile characterizes the two clusters of volcanoes with different height ranges and evolution. The lava tablelands and volcanic cones are distributed in nearly EW-trending belts, where tableland coverage was delineated with superposed layers of gradients and degrees of relief. According to the morphology, the volcanic cones were classified into four types: conical, composite, dome, and shield. The formation causes and classification basis for each type of volcanic cone were analyzed and their parameters were extracted. The H/D ratios of all types of volcanic cones were then statistically determined and projected to create a map of volcanic density distribution. Based on the relationship between distribution and time sequence of the formation of different volcanic cones, it can be inferred that the volcanic eruptions migrated from the margins to the center of the lava plateau. The central area was formed through superposition of multi-stage eruptive materials. In addition

  11. Volcanic caves of East Africa - an overview

    Directory of Open Access Journals (Sweden)

    Jim W. Simons

    1998-01-01

    Full Text Available Numerous Tertiary to recent volcanoes are located in East Africa. Thus, much of the region is made up volcanic rock, which hosts the largest and greatest variety of East Africas caves. Exploration of volcanic caves has preoccupied members of Cave Exploration Group of East Africa (CEGEA for the past 30 years. The various publications edited by CEGEA are in this respect a treasure troves of speleological information. In the present paper an overview on the most important volcanic caves and areas are shortly reported.

  12. Toward Forecasting Volcanic Eruptions using Seismic Noise

    CERN Document Server

    Brenguier, Florent; Campillo, Michel; Ferrazzini, Valerie; Duputel, Zacharie; Coutant, Olivier; Nercessian, Alexandre

    2007-01-01

    During inter-eruption periods, magma pressurization yields subtle changes of the elastic properties of volcanic edifices. We use the reproducibility properties of the ambient seismic noise recorded on the Piton de la Fournaise volcano to measure relative seismic velocity variations of less than 0.1 % with a temporal resolution of one day. Our results show that five studied volcanic eruptions were preceded by clearly detectable seismic velocity decreases within the zone of magma injection. These precursors reflect the edifice dilatation induced by magma pressurization and can be useful indicators to improve the forecasting of volcanic eruptions.

  13. Shattering the Glass Ceiling

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ "Shattering the Glass Ceiling: the Myths, Opportunities and Chal lenges of Women in Corporate China" was the theme of CEIBS'first Women in Management Forum held on December l 1 on the school's main campus in Shanghai.

  14. Glass Stronger than Steel

    Science.gov (United States)

    Yarris, Lynn

    2011-03-28

    A new type of damage-tolerant metallic glass, demonstrating a strength and toughness beyond that of steel or any other known material, has been developed and tested by a collaboration of researchers from Berkeley Lab and Caltech.

  15. Glass for Solar Concentrators

    Science.gov (United States)

    Bouquet, F. L.

    1984-01-01

    Report identifies four commercially available glasses as promising reflectors for solar concentrators. Have properties of high reflectance (80 to 96 percent), lower cost than first-surface silver metalization, and resistance to environmental forces.

  16. Fission-track dating of South American natural glasses: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Bigazzi, G. [Istituto di Geoscienze e Georisorse, C.N.R., Via G. Moruzzi, 1, 56124 Pisa (Italy)]. E-mail: g.bigazzi@igg.cnr.it; Hadler Neto, J.C. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-970 Campinas SP (Brazil); Iunes, P.J. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-970 Campinas SP (Brazil); Osorio Araya, A.M. [Departamento de Fisica, Quimica e Biologia, Universidade do Estado de Sao Paulo, UNESP, 19060-900 Presidente Prudente SP (Brazil)

    2005-12-01

    Although many glass-bearing horizons can be found in South American volcanic complexes or sedimentary series, only a relatively few tephra and obsidian-bearing volcanic fields have been studied using the fission-track (FT) dating method. Among them, the volcanics located in the Sierra de Guamani (east of Quito, Ecuador) were studied by several authors. Based upon their ages, obsidians group into three clusters: (1) very young obsidians, {approx}0.2Ma old (2) intermediate-age obsidians, {approx}0.4-{approx}0.8Ma old, and (3) older obsidians, {approx}1.4-{approx}1.6Ma old. The FT method is also an efficient alternative technique for identification of the sources of prehistoric obsidian artefacts. Provenance studies carried out in South America have shown that the Sierra de Guamani obsidian occurrences were important sources of raw material for tool making during pre-Columbian times. Glasses originated from these sources were identified in sites distributed over relatively wide areas of Ecuador and Colombia. Only a few systematic studies on obsidians in other sectors were carried out. Nevertheless, very singular glasses have been recognised in South America, such as Macusanite (Peru) and obsidian Quiron (Argentina), which are being proposed as additional reference materials for FT dating. Analyses of tephra beds interstratified with sedimentary deposits revealed the performance of FT dating in tephrochronological studies. A remarkable example is the famous deposit outcropping at Farola Monte Hermoso, near Bahia Blanca (Buenos Aires Province), described for the first time by the middle of the 19th century by Charles Darwin. Considering the large number of volcanic glasses that were recognised in volcanic complexes and in sedimentary series, South America is a very promising region for the application of FT dating. The examples given above show that this technique may yield important results in different disciplinary fields.

  17. Volcanic Plume Measurements with UAV (Invited)

    Science.gov (United States)

    Shinohara, H.; Kaneko, T.; Ohminato, T.

    2013-12-01

    Volatiles in magmas are the driving force of volcanic eruptions and quantification of volcanic gas flux and composition is important for the volcano monitoring. Recently we developed a portable gas sensor system (Multi-GAS) to quantify the volcanic gas composition by measuring volcanic plumes and obtained volcanic gas compositions of actively degassing volcanoes. As the Multi-GAS measures variation of volcanic gas component concentrations in the pumped air (volcanic plume), we need to bring the apparatus into the volcanic plume. Commonly the observer brings the apparatus to the summit crater by himself but such measurements are not possible under conditions of high risk of volcanic eruption or difficulty to approach the summit due to topography etc. In order to overcome these difficulties, volcanic plume measurements were performed by using manned and unmanned aerial vehicles. The volcanic plume measurements by manned aerial vehicles, however, are also not possible under high risk of eruption. The strict regulation against the modification of the aircraft, such as installing sampling pipes, also causes difficulty due to the high cost. Application of the UAVs for the volcanic plume measurements has a big advantage to avoid these problems. The Multi-GAS consists of IR-CO2 and H2O gas analyzer, SO2-H2O chemical sensors and H2 semiconductor sensor and the total weight ranges 3-6 kg including batteries. The necessary conditions of the UAV for the volcanic plumes measurements with the Multi-GAS are the payloads larger than 3 kg, maximum altitude larger than the plume height and installation of the sampling pipe without contamination of the exhaust gases, as the exhaust gases contain high concentrations of H2, SO2 and CO2. Up to now, three different types of UAVs were applied for the measurements; Kite-plane (Sky Remote) at Miyakejima operated by JMA, Unmanned airplane (Air Photo Service) at Shinomoedake, Kirishima volcano, and Unmanned helicopter (Yamaha) at Sakurajima

  18. El Chichon volcanic ash in the stratosphere - Particle abundances and size distributions after the 1982 eruption

    Science.gov (United States)

    Gooding, J. L.; Clanton, U. S.; Gabel, E. M.; Warren, J. L.

    1983-11-01

    Volcanic ash particles collected from the stratosphere after the March/April, 1982 explosive eruption of El Chichon volcano, Mexico, were mostly 2-40 micron vesicular shards of silicic volcanic glass that varied in abundance, at 16.8-19.2 km altitude, from 200 per cu m (30-49 deg N lat.) in May to 1.3 per cu m (45-75 deg N) in October. At the minimum, the ash cloud covered latitudes 10-60 deg N in July and 10 deg S-75 deg N in October. In May and July, ash particles were mostly free, individual shards (and clusters of shards) but, by October, were intimately associated with liquid droplets (presumably, sulfuric acid). In May 1982, the total stratospheric burden of ash was at least 240 tons (2.2 x 10 to the 8th g) although the total ash injected into the stratosphere by the eruption was probably 480-8400 tons.

  19. Formation of Silicon Carbide Using Volcanic Ash as Starting Material and Concentrated Sunlight as Energy Resource

    Directory of Open Access Journals (Sweden)

    Kensuke Nishioka

    2015-01-01

    Full Text Available SiC was formed using volcanic ash as starting material and concentrated sunlight as energy resource. The solar furnace was composed of two parts: Fresnel lens and reacting furnace. The reacting furnace was composed of a cylindrical vacuum chamber and quartz glass plate functioning to guide the concentrated sunlight into the furnace and was placed at the focal point of the Fresnel lens. The sample was made from the mixture of silica formed from volcanic ash and graphite and placed in the carbon crucible inside the reacting furnace. The temperature in the carbon crucible reached more than 1500°C. After the reaction using concentrated light, β-SiC was formed. The weight % of formed SiC was 90.5%.

  20. Carbothermal reduction process of silica formed from shirasu volcanic ash using solar furnace

    Directory of Open Access Journals (Sweden)

    Hatakeyama Keisuke

    2016-01-01

    Full Text Available Metallurgical grade silicon was formed using Shirasu volcanic ash as starting material with solar furnace. The solar furnace was composed of two parts: Fresnel lens and reacting furnace. The reacting furnace was composed of a cylindrical vacuum chamber and quartz glass plate functioning to guide the concentrated sunlight into the furnace, and was placed at the focal point of the Fresnel lens. The sample was made from a mixture of silica formed from Shirasu volcanic ash and carbon, and placed in the carbon crucible inside the reacting furnace. The sample was irradiated for 3 hours, and the furnace was left until it cooled down to room temperature. After the cooling process, the sample was mixed and placed in the carbon crucible, and it was irradiated and cooled with the same processes again. After the experiment, the sample was evaluated by X-ray diffraction and the production of silicon was confirmed.

  1. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    to breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... the mechanical behavior of the beam is explained. Finally, some design criterions for reinforced glass beams are discussed....

  2. Baseline LAW Glass Formulation Testing

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States); Mooers, Cavin [The Catholic University of America, Washington, DC (United States). Vitreous State Lab.; Bazemore, Gina [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Pegg, Ian L. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Hight, Kenneth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Lai, Shan Tao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Buechele, Andrew [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Rielley, Elizabeth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Gan, Hao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Muller, Isabelle S. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Cecil, Richard [The Catholic University of America, Washington, DC (United States). Vitreous State Lab

    2013-06-13

    The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements.

  3. Development of a novel aluminum-free glass ionomer cement based on magnesium/strontium-silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Ae [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Abo-Mosallam, Hany A. [Glass Research Department, National Research Centre, Dokki, Cairo (Egypt); Lee, Hye-Young [Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Kim, Gyu-Ri [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Kim, Hae-Won [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Lee, Hae-Hyoung, E-mail: haelee@dku.edu [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of)

    2014-09-01

    The effects of strontium substitution for magnesium in a novel aluminum-free multicomponent glass composition for glass ionomer cements (GICs) were investigated. A series of glass compositions were prepared based on SiO{sub 2}-P{sub 2}O{sub 5}-CaO-ZnO-MgO{sub (1-X)}-SrO{sub X}-CaF{sub 2} (X = 0, 0.25, 0.5 and 0.75). The mechanical properties of GICs prepared were characterized by compressive strength, flexural strength, flexural modules, and microhardness. Cell proliferation was evaluated indirectly by CCK-8 assay using various dilutions of the cement and rat mesenchyme stem cells. Incorporation of strontium instead of magnesium in the glasses has a significant influence on setting time of the cements and the properties. All mechanical properties of the GICs with SrO substitution at X = 0.25 were significantly increased, then gradually decreased with further increase of the amount of strontium substitution in the glass. The GIC at X = 0.25, also, showed an improved cell viability at low doses of the cement extracts in comparison with other groups or control without extracts. The results of this study demonstrate that the glass compositions with strontium substitution at low levels can be successfully used to prepare aluminum-free glass ionomer cements for repair and regeneration of hard tissues. - Highlights: • We developed multicomponent glass compositions for a novel aluminum-free glass ionomer cement (GIC). • The effects of MgO replacement with SrO in the glasses on the mechanical properties and cell proliferation were evaluated. • Substitution of MgO with SrO at low levels led to improvement of mechanical properties and cell viability of the cements. • Microstructural degradations in the cement matrix of the GICs with strontium at high levels were observed after aging.

  4. Wastes based glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    Barbieri, L.

    2001-12-01

    Full Text Available Actually, the inertization, recovery and valorisation of the wastes coming from municipal and industrial processes are the most important goals from the environmental and economical point of view. An alternative technology capable to overcome the problem of the dishomogeneity of the raw material chemical composition is the vitrification process that is able to increase the homogeneity and the constancy of the chemical composition of the system and to modulate the properties in order to address the reutilization of the waste. Moreover, the glasses obtained subjected to different controlled thermal treatments, can be transformed in semy-cristalline material (named glass-ceramics with improved properties with respect to the parent amorphous materials. In this review the tailoring, preparation and characterization of glasses and glass-ceramics obtained starting from municipal incinerator grate ash, coal and steel fly ashes and glass cullet are described.

    Realmente la inertización, recuperación y valorización de residuos que proceden de los procesos de incineración de residuos municipales y de residuos industriales son metas importantes desde el punto de vista ambiental y económico. Una tecnología alternativa capaz de superar el problema de la heterogeneidad de la composición química de los materiales de partida es el proceso de la vitrificación que es capaz de aumentar la homogeneidad y la constancia de la composición química del sistema y modular las propiedades a fin de la reutilización del residuo. En este artículo se presentan los resultados de vitrificación en que los vidrios fueron sometidos a tratamientos térmicos controlados diferentes, de manera que se transforman en materiales semicristalinos (también denominados vitrocerámicos con mejores propiedades respecto a los materiales amorfos originales. En esta revisión se muestra el diseño, preparación y caracterización de vidrios y vitrocerámicos partiendo de

  5. Ion-Exchange Interdiffusion Model with Potential Application to Long-Term Nuclear Waste Glass Performance

    Energy Technology Data Exchange (ETDEWEB)

    Neeway, James J.; Kerisit, Sebastien N.; Liu, Jia; Zhang, Jiandong; Zhu, Zihua; Riley, Brian J.; Ryan, Joseph V.

    2016-05-05

    Abstract: Ion exchange is an integral mechanism influencing the corrosion of glasses. Due to the formation of alteration layers in aqueous conditions, it is difficult to conclusively deconvolute the process of ion exchange from other processes, principally dissolution of the glass matrix. Therefore, we have developed a method to isolate alkali diffusion that involves contacting glass coupons with a solution of 6LiCl dissolved in functionally inert dimethyl sulfoxide. We employ the method at temperatures ranging from 25 to 150 °C with various glass formulations. Glass compositions include simulant nuclear waste glasses, such as SON68 and the international simple glass (ISG), glasses in which the nature of the alkali element was varied, and glasses that contained more than one alkali element. An interdiffusion model based on Fick’s second law was developed and applied to all experiments to extract diffusion coefficients. The model expands established models of interdiffusion to the case where multiple types of alkali sites are present in the glass. Activation energies for alkali ion exchange were calculated and the results are in agreement with those obtained in glass strengthening experiments but are nearly five times higher than values reported for diffusion-controlled processes in nuclear waste glass corrosion experiments. A discussion of the root causes for this apparent discrepancy is provided. The interdiffusion model derived from laboratory experiments is expected to be useful for modeling glass corrosion in a geological repository when the silicon concentration is high.

  6. Volcanic Ash Advisory Database, 1983-2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanic ash is a significant hazard to aviation and can also affect global climate patterns. To ensure safe navigation and monitor possible climatic impact, the...

  7. Palaeoclimate: Volcanism caused ancient global warming

    Science.gov (United States)

    Meissner, Katrin J.; Bralower, Timothy J.

    2017-08-01

    A study confirms that volcanism set off one of Earth's fastest global-warming events. But the release of greenhouse gases was slow enough for negative feedbacks to mitigate impacts such as ocean acidification. See Letter p.573

  8. Volcanics in the Gulf Coast [volcanicg

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The volcanic provinces are modified after Plate 2, Principal structural features, Gulf of Mexico Basin (compiled by T.E. Ewing and R.F. Lopez) in Volume J, The...

  9. Development of a novel aluminum-free glass ionomer cement based on magnesium/strontium-silicate glasses.

    Science.gov (United States)

    Kim, Dong-Ae; Abo-Mosallam, Hany A; Lee, Hye-Young; Kim, Gyu-Ri; Kim, Hae-Won; Lee, Hae-Hyoung

    2014-09-01

    The effects of strontium substitution for magnesium in a novel aluminum-free multicomponent glass composition for glass ionomer cements (GICs) were investigated. A series of glass compositions were prepared based on SiO2-P2O5-CaO-ZnO-MgO(1-X)-SrOX-CaF2 (X=0, 0.25, 0.5 and 0.75). The mechanical properties of GICs prepared were characterized by compressive strength, flexural strength, flexural modules, and microhardness. Cell proliferation was evaluated indirectly by CCK-8 assay using various dilutions of the cement and rat mesenchyme stem cells. Incorporation of strontium instead of magnesium in the glasses has a significant influence on setting time of the cements and the properties. All mechanical properties of the GICs with SrO substitution at X=0.25 were significantly increased, then gradually decreased with further increase of the amount of strontium substitution in the glass. The GIC at X=0.25, also, showed an improved cell viability at low doses of the cement extracts in comparison with other groups or control without extracts. The results of this study demonstrate that the glass compositions with strontium substitution at low levels can be successfully used to prepare aluminum-free glass ionomer cements for repair and regeneration of hard tissues.

  10. Volcanism and associated hazards: the Andean perspective

    Directory of Open Access Journals (Sweden)

    R. I. Tilling

    2009-12-01

    Full Text Available Andean volcanism occurs within the Andean Volcanic Arc (AVA, which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions" recognized worldwide that have occurred from the Ordovician to the Pleistocene.

    The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru. The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (<0.05 km3 in 1985 of Nevado del Ruiz (Colombia killed about 25 000 people – the worst volcanic disaster in the Andean region as well as the second worst in the world in the 20th century. The Ruiz tragedy has been attributed largely to ineffective communications of hazards information and indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent

  11. Optimized Synthesis of Foam Glass from Recycled CRT Panel Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Most of the panel glass from cathode ray tubes (CRTs) is landfilled today. Instead of landfilling, the panel glass can be turned into new environment-friendly foam glass. Low density foam glass is an effective heat insulating material and can be produced just by using recycle glass and foaming...... additives. In this work we recycle the CRT panel glass to synthesize the foam glass as a crucial component of building and insulating materials. The synthesis conditions such as foaming temperature, duration, glass particle size, type and concentrations of foaming agents, and so on are optimized...... by performing systematic experiments. In particular, the concentration of foaming agents is an important parameter that influences the size of bubbles and the distribution of bubbles throughout the sample. The foam glasses are characterised regarding density and open/closed porosity. Differential scanning...

  12. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

  13. About the Mechanism of Volcanic Eruptions

    CERN Document Server

    Nechayev, Andrei

    2012-01-01

    A new approach to the volcanic eruption theory is proposed. It is based on a simple physical mechanism of the imbalance in the system "magma-crust-fluid". This mechanism helps to explain from unified positions the different types of volcanic eruptions. A criterion of imbalance and magma eruption is derived. Stratovolcano and caldera formation is analyzed. High explosive eruptions of the silicic magma is discussed

  14. Episodic Volcanism and Geochemistry in Western Nicaragua

    Science.gov (United States)

    Saginor, I.; Carr, M. J.; Gazel, E.; Swisher, C.; Turrin, B.

    2007-12-01

    The active volcanic arc in western Nicaragua is separated from the Miocene arc by a temporal gap in the volcanic record, during which little volcanic material was erupted. Previous work suggested that this gap lasted from 7 to 1.6 Ma, during which volcanic production in Nicaragua was limited or nonexistent. Because the precise timing and duration of this gap has been poorly constrained, recent fieldwork has focused on locating samples that may have erupted close to or even during this apparent hiatus in activity. Recent 40Ar/39Ar dates reveal pulses of low- level episodic volcanism at 7 Ma and 1 Ma between the active and Miocene arcs with current volcanism beginning ~350 ka. In addition, sampling from an inactive area between Coseguina and San Cristobal yielded two distinct groupings of ages; one of Tamarindo age (13 Ma) and the other around 3.5 Ma-the only samples of that age collected on-strike with the active arc. This raises the possibility the bases of the other active volcanoes contain lavas that are older than expected, but have been covered by subsequent eruptions. The Miocene arc differs from the active arc in Central America in several ways, with the latter having higher Ba/La and U/Th values due to increased slab input and changes in subducted sediment composition. Analysis of sample C-51 and others taken from the same area may shed light on the timing of this shift from high to low Ba/La and U/Th values. More importantly, it may help explain why the arc experienced such a dramatic downturn in volcanic production during this time. We also report 25 new major and trace element analyses that shed some light on the origins of these minor episodes of Nicaraguan volcanism. These samples are currently awaiting Sr and Nd isotopic analyses.

  15. Thermal Stability of Volcanic Ash versus Turbine Ingestion Test Sands: an Experimental Investigation

    Science.gov (United States)

    Cimarelli, C.; Kueppers, U.; Hess, K.; Dingwell, D. B.; Rickerby, D. S.; Madden, P. C.

    2010-12-01

    Volcanic eruptions are an inevitable natural threat. The range of eruptive styles is large and short term fluctuations of explosivity or vent position pose a large risk not necessarily confined to the immediate vicinity of a volcano. Explosive eruptions rather may also affect aviation, infrastructure and climate, regionally as well as globally. The recent eruption of Eyjafjallajökull drastically brought into common awareness how volcanic activity can affect every day’s life and disrupt air traffic. The presence of solid particles in the air ingested in jet turbines may cause harm as it 1) may deposit on surfaces upon being heated up and 2) abrade upon impact. Particles suspended in the atmosphere may have different origins, including volcanic ash, aeolian sand, or incineration residues, each of them having different chemical and physical characteristics. To date, aircraft turbine operability has been investigated - amongst other tests - through the ingestion of sands whose grains have different mineralogical nature. Due to high cooling rates, volcanic ash is usually made up of glass, i.e. an amorphous phase lacking crystallographic order. Glass and crystal behave very differently to heating up. Glass will soften - and accordingly change shape or stick to surfaces - at temperatures as low as 700 °C, depending on the chemical composition. Crystals however need higher melting temperatures; quartz for example has a melting point at around 1700 °C. Accordingly, the effect of ash on the operational reliability of aircraft turbines may not be judged solely based on knowledge commonly derived from mineral sand ingestion testing. In order to investigate the behaviour upon heating, we performed a series of experiments at ten temperature steps between 700 and 1600 °C. We used three different samples: 1) Ash from the explosive phase of Eyjafjallajökull; 2) MIL E-5007C test sand (MTS), and 3) Arizona Test Dust (ATD). MTS and ATD are commonly used for aircraft turbine

  16. Deposition or not? The fate of volcanic ash after aggregation processes

    Science.gov (United States)

    Mueller, Sebastian B.; Kueppers, Ulrich; Wadsworth, Fabian B.; Ayris, Paul M.; Casas, Ana S.; Cimarelli, Corrado; Ametsbichler, Jonathan; Delmelle, Pierre; Taddeucci, Jacopo; Jacob, Michael; Dingwell, Donald B.

    2017-04-01

    In the course of explosive volcanic eruptions, large amounts of ash are released into the atmosphere and may subsequently pose a threat to infrastructure, such as aviation industry. Ash plume forecasting is therefore a crucial tool for volcanic hazard mitigation but may be significantly affected by aggregation, altering the aerodynamic properties of particles. Models struggle with the implementation of aggregation since external conditions promoting aggregation have not been completely understood; in a previous study we have shown the rapid generation of ash aggregates through liquid bonding via the use of fluidization bed technology and further defined humidity and temperature ranges necessary to trigger aggregation. Salt (NaCl) was required for the recovery of stable aggregates, acting as a cementation agent and granting aggregate cohesion. A numerical model was used to explain the physics behind particle aggregation mechanisms and further predicted a dependency of aggregation efficiency on liquid binder viscosity. In this study we proof the effect of viscosity on particle aggregation. HCl and H2SO4 solutions were diluted to various concentrations resulting in viscosities between 1 and 2 mPas. Phonolitic and rhyolitic ash samples as well as soda-lime glass beads (serving as analogue material) were fluidized in the ProCell Lab® of Glatt Ingenieurtechnik GmbH and treated with the acids via a bottom-spray technique. Chemically driven interaction between acid liquids and surfaces of the three used materials led to crystal precipitation. Salt crystals (e.g. NaCl) have been confirmed through scanning electron microscopy (SEM) and leachate analysis. Both volcanic ash samples as well as the glass beads showed a clear dependency of aggregation efficiency on viscosity of the sprayed HCl solution. Spraying H2SO4 provoked a collapse of the fluidized bed and no aggregation has been observed. This is accounted by the high hygroscopicity of H2SO4. Dissolving CaCl2 (known to be

  17. Volcanic loading: The dust veil index

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, H.H. [Univ. of East Anglia, Norwich (United Kingdom). Climatic Research Unit

    1985-09-01

    Dust ejected into the high atmosphere during explosive volcanic eruptions has been considered as a possible cause for climatic change. Dust veils created by volcanic eruptions can reduce the amount of light reaching the Earth`s surface and can cause reductions in surface temperatures. These climatic effects can be seen for several years following some eruptions and the magnitude and duration of the effects depend largely on the density or amount of tephra (i.e. dust) ejected, the latitude of injection, and atmospheric circulation patterns. Lamb (1970) formulated the Dust Veil Index (DVI) in an attempt to quantify the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact of a particular volcanic eruptions release of dust and aerosols over the years following the event. The DVI for any volcanic eruptions are available and have been used in estimating Lamb`s dust veil indices.

  18. Small volcanic eruptions and the stratospheric sulfate aerosol burden

    Science.gov (United States)

    Pyle, David M.

    2012-09-01

    (Rampino and Self 1984, Pyle et al 1996, Self and Rampino 2012). But as yet, there is little evidence for the consequences of this scale of eruption for the climate system (Miles et al 2004), and few data against which to test simulations of stratospheric sulfur-injection 'geoengineering' scenarios of a similar scale and frequency (e.g. English et al 2012). A hint of the new volcano-observing capability came during the eruption of Eyjafjallajökull, Iceland. For a few days in April 2010 meteorological conditions, coupled with a dramatic increase in volcanic ash production, led to the wide dispersal of fine volcanic particles across northern Europe; an event which was widely tracked by ground-based and satellite-borne instruments, augmented by in situ measurements from balloons and aircraft (Bennett et al 2010, Flentje et al 2010, Harrison et al 2010, Stohl et al 2011). Despite the interest in Eyjafjallajökull at the time, this was, geologically, only a very modest eruption with limited sulfur emissions and an impact restricted mainly to the regional troposphere (e.g. Thomas and Prata 2011, Walker et al 2012). Then, in June 2011, a previously dormant volcano in north-east Africa began to erupt violently. Little is known about Nabro, which is a partially collapsed volcano that straddles the Eritrea-Ethiopia border, and has had no known historical activity (Wiart and Oppenheimer 2005). Despite the remote location, and lack of prior warning, the event and its aftermath were remarkably well captured by remote-sensing instruments, as demonstrated in the new letter by Sawamura et al (2012). Using both ground-based and satellite-borne laser-ranging (lidar) data, Sawamura et al (2012) were able to extract detailed information about the nature of the volcanic aerosol layer, and its spread around the globe. The eruption started strongly, with substantial ash plumes for the first 48 h, rising to 9-14 km altitude (Smithsonian Institution 2011, Bourassa et al 2012), that carried at

  19. Occurrence of volcanic ash in the Quaternary alluvial deposits, lower Narmada basin, western India

    Indian Academy of Sciences (India)

    Rachna Raj

    2008-02-01

    This communication reports the occurrence of an ash layer intercalated within the late Quaternary alluvial succession of the Madhumati River, a tributary of the lower Narmada River. Petrographic, morphological and chemical details of glass shards and pumice fragments have formed the basis of this study. The ash has been correlated with the Youngest Toba Tuff. The finding of ash layer interbedded in Quaternary alluvial sequences of western Indian continental margin is significant, as ash being datable material, a near precise time-controlled stratigraphy can be interpreted for the Quaternary sediments of western India. The distant volcanic source of this ash requires a fresh re-assessment of ash volume and palaeoclimatic interpretations.

  20. High spatial resolution geochemistry and textural characteristics of 'microtektite' glass spherules in proximal Cretaceous-Paleogene sections: Insights into glass alteration patterns and precursor melt lithologies

    Science.gov (United States)

    Belza, Joke; Goderis, Steven; Smit, Jan; Vanhaecke, Frank; Baert, Kitty; Terryn, Herman; Claeys, Philippe

    2015-03-01

    Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), we have conducted spatially resolved trace element analysis on fresh, unaltered microtektite glasses linked to the Cretaceous-Paleogene (K-Pg) boundary Chicxulub crater and on their surrounding alteration phases. This unique approach offers the opportunity to study in situ and at high spatial resolution both the mixing of different target lithologies and the variation of the major and trace element budget during the alteration process. In addition, two-dimensional element distribution maps reveal important geochemical information beyond the capabilities of single spot laser drilling. Glasses from two localities in opposite quadrants from the source crater were studied. At the Beloc locality (Haiti), the glass population is dominated by the presence of yellow high-Ca glass and black andesitic glass formed by admixture of carbonate/dolomite/anhydrite platform lithologies with crystalline basement. These glasses alter according to the well-established hydration-palagonitization model postulated for mafic volcanic glasses. REEs become progressively leached from the glass to below the detection limit for the applied spot size, while immobile Zr, Hf, Nb, and Ta passively accumulate in the process exhibiting both inter-element ratios and absolute concentrations similar to those for the original glass. In contrast, The Arroyo El Mimbral locality (NE Mexico) is characterized by abundant green glass fragments high in Si, Al and alkalis, and low in Mg, Ca, Fe. Low Si black glass is less abundant though similar in composition to the black glass variety at Beloc. The alteration pattern of high-Si, Al green glass at the Mimbral locality is more complex, including numerous competing reaction processes (ion-exchange, hydration, dissolution, and secondary mineral precipitation) generally controlled by the pH and composition of the surrounding fluid. All green, high-Si, Al glasses are hydrated and

  1. Volcanic plumes fast detection: a methodological proposal for an integrated approach

    Science.gov (United States)

    Bernabeo, R. Alberto; Tositti, Laura; Brattich, Erika

    2017-04-01

    The behaviour of erupting volcanoes ranges from the quiet, steady effusion of lava to highly explosive eruptions. Therefore volcanic eruptions may present a direct threat to the safety of aircraft in flight and major operational difficulties at aerodromes and in airspaces located downwind the resulting volcanic ash cloud, in particular when eruptions are of high intensity and/or prolonged. Since volcanic ash clouds and gases are not displayed on either airborne or ATC radar and are extremely difficult to identify at night, pilots must rely on reports from air traffic controllers and from other pilots to determine the location of an ash cloud or gases. As a result, there is a clear need to develop extra tools enabling the timely on-board sensing of volcanic plumes for the sake of safety purposes. Large scale eruptions may eject many cubic kilometres of glass particles and pulverized rock (volcanic ash) as well as corrosive/hazardous gases high into the atmosphere, potentially over a wide area for timescales ranging from hours to weeks or even months. Volcanic ash consists mostly of sharp-edged, hard glass particles and pulverized rock. It is very abrasive and, being largely composed of siliceous materials, has a melting temperature below the operating temperature of modern turbine engines at cruise thrust. A volcanic plume in fact contains a complex mixture of water vapour, sulphur dioxide (producing sulphuric acid as a result of gas-to particle conversions reaction catalysed by iron in cloud droplets), chlorine and other halogens, and trace elements which are highly reactive and may interact with the mineral particles to produce corrosive effects hazardous to both airframes and human health. Remotely piloted aircraft system (RPAS) or Unmanned aerial vehicles (UAV) are slowly becoming efficient platforms - with dedicated miniaturized sensors that can be used in scientific/commercial remote sensing applications - and are of fundamental support to the planning

  2. Effect of Miocene basaltic volcanism in Shanwang (Shandong Province, China) on environmental changes

    Institute of Scientific and Technical Information of China (English)

    GUO; ZhengFu; LIU; JiaQi; CHEN; XiaoYu

    2007-01-01

    Miocene (16-10 Ma) basalts, together with significantly well-preserved fossils (including animal and plant fossils) in the contemporaneously tephra-rich Maar sediments, are located in Shanwang volcanic region, Shandong Province, China. Distribution area of the basaltic eruption products is about 240 km2. Detailed field observations indicate that most of basaltic rocks are fissure eruptive products and some are central eruptives constrained by linear faults. The well-preserved fossils in the lacustrine deposits have been considered to be a result of mass mortalities. Based on physically volcanologic modeling results, eruption column of the basaltic fissure activities in the Shanwang volcanic region is estimated to have entered the stratosphere. Petrographic observations indicate that the basalts have porphyritic textures with phenocrysts of olivine, pyroxene, plagioclase feldspar and alkali feldspar setting in groundmass of plagioclase feldspar, alkali feldspar, quartz, apatite and glass. Based on observations of tephra, tuff and tuffites collected in the Maar sediments of the Shanwang area, we determined major element oxide concentrations and volatile composition of melt inclusions in phenocrysts and matrix glasses by electron microprobe analysis. Volatile (including S, Cl, F and H2O) concentrations erupted into the stratosphere were estimated by comparing pre- and post-eruptive volatile concentrations. Our determination results show that contents of S, Cl, F and H2O emitted into the stratosphere were 0.18%-0.24%, 0.03%-0.05%, 0.03%-0.05% and 0.4%-0.6%, respectively, which was characterized by high-S contents erupted. Amounts of volatiles emitted in the Shanwang volcanic region are much higher than those in eruptions which had a substantial effect on climate and environment. According to the compositions and amounts of the volatiles erupted from the Miocene basaltic volcanism in Shanwang, we propose a hypothesis that volatile-rich basaltic volcanism could result in

  3. Application of MODIS-ASTER (MASTER) simulator data to geological mapping of young volcanic regions in Baja California, Mexico

    Science.gov (United States)

    Dmochowski, Jane Ellen

    Visible, near infrared, short-wave infrared, and thermal infrared multi-channel remote sensing data, MODIS-ASTER (MASTER), are used to extract geologic information from two volcanic regions in Baja California, Mexico: Tres Virgenes-La Reforma Volcanic Region and the volcanic island of Isla San Luis. The visible and near infrared and short-wave infrared data were atmospherically corrected and classified. The resulting classification roughly delineates surfaces that vary in their secondary minerals. Attempts to identify these minerals using ENVI's Spectral Analyst(TM) were moderately successful. The analysis of the thermal infrared data utilizes the shift to longer wavelengths in the Reststrahlen band as the mineralogy changes from felsic to mafic to translate the data into values of weight percent SiO2. The results indicate that the general approach tends to underestimate the weight percent SiO2 in the image. This discrepancy is removed with a "site calibration," which provides good results in the calculated weight percent SiO2 with errors of a few percent. However, errors become larger with rugged topography or low solar angle at the time of image acquisition. Analysis of bathymetric data around Isla San Luis, and consideration of the island's alignment with the Ballenas transform fault zone to the south and volcanic seamounts nearby, suggest Isla San Luis is potentially volcanically active and could be the product of a "leaky" transform fault. The results from the image analysis in the Tres Virgenes-La Reforma Volcanic Region show the La Reforma and El Aguajito volcanic centers to be bimodal in composition and verify the most recent volcanism in the Tres Virgenes region to be basaltic-andesite. The results of fieldwork and image analysis indicate that the volcanic products of the central dome of La Reforma are likely a sequence of welded ash flow tuffs and lavas of varied composition, evidence of its origin as a caldera.

  4. Abundances of F,Cl S and P in Volcanic Magmas and Their Evolution,Wudalianchi

    Institute of Scientific and Technical Information of China (English)

    1991-01-01

    F,Cl,S and P were determined,using electron microprobe,in magmatic inclusions trapped within minerals and glass mesostasis from Wudalianchi volcanic rocks.The initial volcanic magma from Wudalianchi corresponds to the basanitic magma crystallized near the surface(pressure<91Mpa).The potential H2O content of this magma is in the range2-4wt.%.The initial composition of volcanic magmas varies regularly from early to late volcanic events.From the Middle Pleistocene to the recent eruptions(1719-1721yr.),the basicity of volcanic magma tends to increase,as reflected by an increase in MgO and CaO contents and by a progressive decrease in SiO2 and K2O contents.Meanwhile ,from early(Q2) to late(Q3) episodic eruptions of the Middle Pleistocene,the initial concentrations of chlorine in volcanic magmas range from 1430-1930 ppm to 1700 ppm and decrease to 700-970ppm for the first episodic eruption during the Holcene(Q41).The chlorine concentrations of vokanic magmas of recent eruption(Q42) are increased again to 2600-2870 ppm.A parallel evolution trend for phosphorus and chlorine concentrations in magmas has been certified:1500-5970ppm(Q2)→3500-4210ppm(Q3)→1100-3500ppm(Q41)→6800-7900ppm(Q42).The fluorine contents of volcanic magmas,from early to late volcanic events ,show the same trend:770-2470ppm→200-700ppm→700-800ppm.During the crystallization-evolution of volcanic magmas,fluorine and phosphorus tend to be enriched in residual magmas as a result of crystal-melt differentiation,for example,the fluorine contents reach 5000-6800ppm and the phosphorus contents,2.93wt.% in residual magmas.An appreciable amount of chlorine may be lost from water rich volcanic magmas prior to eruption as a result of degassing.Apparently,water serves as a gas carrier for the chlorine.The chlorine contents of residual magmas may decrease to 100-300ppm.The volcanic magmas from Wudalianchi are poor in sulfur,normally ranging from 200 to 400ppm .On account of the behavior of sulfur in magmas

  5. Sol-Gel Glasses

    Science.gov (United States)

    Mukherjee, S. P.

    1985-01-01

    Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

  6. Apollo 15 green glass - Relationships between texture and composition

    Science.gov (United States)

    Steele, Alison M.

    1992-01-01

    A suite of 365 Apollo 15 green-glass particles was analyzed by INAA and then described petrographically so that comparisons between composition and physical characteristics could be made. Nonuniform compositional distributions of crystalline and elongate particles were evident, although differences in the distribution of volatile-element coatings and extent of particle breakage were not as striking. A binomial evaluation of these textures on an intergroup basis supports the previously proposed hypothesis that the green-glass groups formed during discrete eruptive events because the groups that were defined compositionally also show significant differences in the average texture and structure of particles. Furthermore, in at least one case (Group D), intragroup differences in the distribution of vitrophyric and vitric particles were apparent. An extension of previous models for pyroclastic volcanism suggests that this feature may indicate that a systematic change in the composition of ejecta occurred as eruption progressed.

  7. Simulated Lunar Environment Spectra of Silicic Volcanic Rocks: Application to Lunar Domes

    Science.gov (United States)

    Glotch, T. D.; Shirley, K.; Greenhagen, B. T.

    2016-12-01

    Lunar volcanism was dominated by flood-style basaltic volcanism associated with the lunar mare. However, since the Apollo era it has been suggested that some regions, termed "red spots," are the result of non-basaltic volcanic activity. These early suggestions of non-mare volcanism were based on interpretations of rugged geomorphology resulting from viscous lava flows and relatively featureless, red-sloped VNIR spectra. Mid-infrared data from the Diviner Lunar Radiometer Experiment on the Lunar Reconnaissance Orbiter have confirmed that many of the red spot features, including Hansteen Alpha, the Gruithuisen Domes, the Mairan Domes, Lassell Massif, and Compton Belkovich are silicic volcanic domes. Additional detections of silicic material in the Aristarchus central peak and ejecta suggest excavation of a subsurface silicic pluton. Other red spots, including the Helmet and Copernicus have relatively low Diviner Christiansen feature positions, but they are not as felsic as the features listed above. To date, the SiO2 content of the silicic dome features has been difficult to quantitatively determine due to the limited spectral resolution of Diviner and lack of terrestrial analog spectra acquired in an appropriate environment. Based on spectra of pure mineral and glass separates, preliminary estimates suggest that the rocks comprising the lunar silicic domes are > 65 wt.% SiO2. In an effort to better constrain this value, we have acquired spectra of andesite, dacite, rhyolite, pumice, and obsidian rock samples under a simulated lunar environment in the Planetary and Asteroid Regolith Spectroscopy Environmental Chamber (PARSEC) at the Center for Planetary Exploration at Stony Brook University. This presentation will discuss the spectra of these materials and how they relate to the Diviner measurements of the lunar silicic dome features.

  8. Bio-Glasses An Introduction

    CERN Document Server

    Jones, Julian

    2012-01-01

    This new work is dedicated to glasses and their variants which can be used as biomaterials to repair diseased and damaged tissues. Bio-glasses are superior to other biomaterials in many applications, such as healing bone by signaling stem cells to become bone cells.   Key features:  First book on biomaterials to focus on bio-glassesEdited by a leading authority on bio-glasses trained by one of its inventors, Dr Larry HenchSupported by the International Commission on Glass (ICG)Authored by members of the ICG Biomedical Glass Committee, with the goal of creating a seamless textb

  9. Glass strengthening and patterning methods

    Science.gov (United States)

    Harper, David C; Wereszczak, Andrew A; Duty, Chad E

    2015-01-27

    High intensity plasma-arc heat sources, such as a plasma-arc lamp, are used to irradiate glass, glass ceramics and/or ceramic materials to strengthen the glass. The same high intensity plasma-arc heat source may also be used to form a permanent pattern on the glass surface--the pattern being raised above the glass surface and integral with the glass (formed of the same material) by use of, for example, a screen-printed ink composition having been irradiated by the heat source.

  10. Glass formation - A contemporary view

    Science.gov (United States)

    Uhlmann, D. R.

    1983-01-01

    The process of glass formation is discussed from several perspectives. Particular attention is directed to kinetic treatments of glass formation and to the question of how fast a given liquid must be cooled in order to form a glass. Specific consideration is paid to the calculation of critical cooling rates for glass formation, to the effects of nucleating heterogeneities and transients in nucleation on the critical cooling rates, to crystallization on reheating a glass, to the experimental determination of nucleation rates and barriers to crystal nucleation, and to the characteristics of materials which are most conducive to glass formation.

  11. Heavy Metal Fluoride Glasses.

    Science.gov (United States)

    1987-04-01

    i 2N E ihhhhh1112h MEmhhhhEEEohhhhE I.’....momo 111111111’-20 LA ’Ll2. AFWL-TR-86-37 AFWL-TR- 86-37 oT C ,l C ’-’ N HEAVY METAL FLUORIDE GLASSES 0nI...Secwrit CkasmfcationJ HEAVY METAL FLUORIDE GLASSES 12. PERSONAL AUTHOR(S) Reisfield, Renata; and Eyal, Mrek 13. TYPE OF REPORT 113b. TIME COVERED 114...glasses containing about 50 mole% of ZrF4 [which can be replaced by HfF 4 or TIF 4 (Refs. 1-3) or heavy metal fluorides based on PbF2 and on 3d-group

  12. Perspectives on spin glasses

    CERN Document Server

    Contucci, Pierluigi

    2013-01-01

    Presenting and developing the theory of spin glasses as a prototype for complex systems, this book is a rigorous and up-to-date introduction to their properties. The book combines a mathematical description with a physical insight of spin glass models. Topics covered include the physical origins of those models and their treatment with replica theory; mathematical properties like correlation inequalities and their use in the thermodynamic limit theory; main exact solutions of the mean field models and their probabilistic structures; and the theory of the structural properties of the spin glass phase such as stochastic stability and the overlap identities. Finally, a detailed account is given of the recent numerical simulation results and properties, including overlap equivalence, ultrametricity and decay of correlations. The book is ideal for mathematical physicists and probabilists working in disordered systems.

  13. Venus volcanism - Classification of volcanic features and structures, associations, and global distribution from Magellan data

    Science.gov (United States)

    Head, James W.; Crumpler, L. S.; Aubele, Jayne C.; Guest, John E.; Saunders, R. S.

    1992-01-01

    A classification and documentation of the range of morphologic features and structures of volcanic origin on Venus, their size distribution, and their global distribution and associations are presented based on a preliminary analysis of Magellan data. Some of the major questions about volcanism on Venus are addressed.

  14. Volcanic Supersites as cross-disciplinary laboratories

    Science.gov (United States)

    Provenzale, Antonello; Beierkuhnlein, Carl; Giamberini, Mariasilvia; Pennisi, Maddalena; Puglisi, Giuseppe

    2017-04-01

    Volcanic Supersites, defined in the frame of the GEO-GSNL Initiative, are usually considered mainly for their geohazard and geological characteristics. However, volcanoes are extremely challenging areas from many other points of view, including environmental and climatic properties, ecosystems, hydrology, soil properties and biogeochemical cycling. Possibly, volcanoes are closer to early Earth conditions than most other types of environment. During FP7, EC effectively fostered the implementation of the European volcano Supersites (Mt. Etna, Campi Flegrei/Vesuvius and Iceland) through the MED-SUV and FUTUREVOLC projects. Currently, the large H2020 project ECOPOTENTIAL (2015-2019, 47 partners, http://www.ecopotential-project.eu/) contributes to GEO/GEOSS and to the GEO ECO Initiative, and it is devoted to making best use of remote sensing and in situ data to improve future ecosystem benefits, focusing on a network of Protected Areas of international relevance. In ECOPOTENTIAL, remote sensing and in situ data are collected, processed and used for a better understanding of the ecosystem dynamics, analysing and modelling the effects of global changes on ecosystem functions and services, over an array of different ecosystem types, including mountain, marine, coastal, arid and semi-arid ecosystems, and also areas of volcanic origin such as the Canary and La Reunion Islands. Here, we propose to extend the network of the ECOPOTENTIAL project to include active Volcanic Supersites, such as Mount Etna and other volcanic Protected Areas, and we discuss how they can be included in the framework of the ECOPOTENTIAL workflow. A coordinated and cross-disciplinary set of studies at these sites should include geological, biological, ecological, biogeochemical, climatic and biogeographical aspects, as well as their relationship with the antropogenic impact on the environment, and aim at the global analysis of the volcanic Earth Critical Zone - namely, the upper layer of the Earth

  15. Genesis of petroduric and petrocalcic horizons in Latinamerica volcanic soils

    Science.gov (United States)

    Quantin, Paul

    2010-05-01

    -arid climate. A complex soil profile of petrocalcic Phaeozem, derived from 4 pyroclastic layers, shows among its successive horizons: in layer 3 the 'upper cangahua' with petrocalcic features and in layer 4 the 'lower cangahua' with hard fragipan properties. The features of the petrocalcic cangahua differ from a Mexican fragipan (Hidalgo & al 1997) by: a hard calcrete, higher alkalinity, stability in water after HCl and NaOH treatment, 2-4% of 'free silica'. The macro and micro-morphology shows: the laminar calcite crust, at the top of cangahua, with alternate micrite-sparite layers; downwards, microcalcite infillings in the voids of a prismatic structure, invading the groundmass by epigenesis of clay sheets, together whith microcrystalline opal. From these data this scenario is inferred: after a former weathering of volcanic glass to form a clayey matrix, as well amorphous silica and microcalcite coatings and infillings, then a second process, perhaps due to drier climate, produced the laminar crust formation, by invasion of microcalcite in the matrix. Conclusion. The petrocalcic horizon in Ecuador was produced by two processes: from a former phase of weathering giving a fragic horizon to a second producing the accumulation of calcite and some opal over and inside the matrix, due to climate change. The petroduric horizon in Mexico, is the product of a very complex soil transformation, from a former clayey Nitisol, through four successive processes: clay eluviation-illuviation, alternate redoximorphy, clay degradation, finally a progressive silicification over and inside the groundmass, probably due to pedoclimate change. References F. Elsass, D. Dubroeucq & M. Thiry. 2000. Clay Minerals, 35, 477-489. C. Hidalgo, P. Quantin & F. Elsass. 1997. Memorias del III Simposio Internacional sobre Suelos volcanicos endurecidos (Quito 1996), p. 65-72. - P. Quantin & C. Zebrowski. 1997. idem, p. 29-47.- J.P. Rossignol & P. Quantin. 1997. idem, p. 73-82.

  16. Volcanic Alert System (VAS) developed during the (2011-2013) El Hierro (Canary Islands) volcanic process

    Science.gov (United States)

    Ortiz, Ramon; Berrocoso, Manuel; Marrero, Jose Manuel; Fernandez-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Garcia, Alicia

    2014-05-01

    In volcanic areas with long repose periods (as El Hierro), recently installed monitoring networks offer no instrumental record of past eruptions nor experience in handling a volcanic crisis. Both conditions, uncertainty and inexperience, contribute to make the communication of hazard more difficult. In fact, in the initial phases of the unrest at El Hierro, the perception of volcanic risk was somewhat distorted, as even relatively low volcanic hazards caused a high political impact. The need of a Volcanic Alert System became then evident. In general, the Volcanic Alert System is comprised of the monitoring network, the software tools for the analysis of the observables, the management of the Volcanic Activity Level, and the assessment of the threat. The Volcanic Alert System presented here places special emphasis on phenomena associated to moderate eruptions, as well as on volcano-tectonic earthquakes and landslides, which in some cases, as in El Hierro, may be more destructive than an eruption itself. As part of the Volcanic Alert System, we introduce here the Volcanic Activity Level which continuously applies a routine analysis of monitoring data (particularly seismic and deformation data) to detect data trend changes or monitoring network failures. The data trend changes are quantified according to the Failure Forecast Method (FFM). When data changes and/or malfunctions are detected, by an automated watchdog, warnings are automatically issued to the Monitoring Scientific Team. Changes in the data patterns are then translated by the Monitoring Scientific Team into a simple Volcanic Activity Level, that is easy to use and understand by the scientists and technicians in charge for the technical management of the unrest. The main feature of the Volcanic Activity Level is its objectivity, as it does not depend on expert opinions, which are left to the Scientific Committee, and its capabilities for early detection of precursors. As a consequence of the El Hierro

  17. Thin-film solar cells on perlite glass-ceramic substrates

    Science.gov (United States)

    Petrosyan, Stepan G.; Babayan, Virab H.; Musayelyan, Ashot S.; Harutyunyan, Levon A.; Zalesski, Valery B.; Kravchenko, Vladimir M.; Leonova, Tatyana R.; Polikanin, Alexander M.; Khodin, Alexander A.

    2013-06-01

    For the first time, thin-film CIGS solar cells have been fabricated by co-evaporation on specially developed non-conducting perlite (an aluminum potassium sodium silicate natural mineral of volcanic origin) glass-ceramic substrates to develop a fully integrated photovoltaic and building element. Such glass-ceramic material can meet the physical requirements to solar cells substrates as well as the cost goals. The preliminary data presented show that CIGS solar cells deposited on ceramic substrates can exhibit efficiency higher than 10%.

  18. Volcanic spreading forcing and feedback in geothermal reservoir development, Amiata Volcano, Italia

    Science.gov (United States)

    Borgia, Andrea; Mazzoldi, Alberto; Brunori, Carlo Alberto; Allocca, Carmine; Delcroix, Carlo; Micheli, Luigi; Vercellino, Alberto; Grieco, Giovanni

    2014-09-01

    -water aquifer) and the rocks of the geothermal field, constitute ideal pathways for water recharge during vapour extraction for geothermal energy production. We think that volcanic spreading could maintain faults in a critically stressed state, facilitating the occurrence of induced and triggered seismicity.

  19. U-series data of recent volcanism at an Axial Volcanic Ridge (Invited)

    Science.gov (United States)

    van Calsteren, P. W.; Thomas, L. E.; Jc024 Shipboard Party

    2010-12-01

    The spreading rate of the Mid Atlantic Ridge, at the area around 45°N is 11mm/y. This is appropriate scaling for mantle horizontal flow and vertical upwelling. However, the accretion of oceanic crust within the median valley graben (MVG), occurs episodically on timescales much longer than years. During the 2008 JC024 cruise various geophysical and bathymetry datasets were collected as well as photographic and video evidence and some 270 rock samples, using ship-borne instruments, a deep-towed platform TOBI and a tethered ROV Isis both in demersal mode and 'flying' at 100m above the seafloor. We1 could identify the overall 'hour-glass' shape of the MVG, the location of the AVR, 'flat-top' features and some smooth areas on either side. Overall we1 counted some 8000 conical or dome-shaped hummocks, which are arranged in lineaments, mostly parallel to the spreading axis. We1 deduced that each hummock is an individual monogenetic volcano. Smooth areas between the AVR and the median valley boundary faults may indicate sheet flows which are probably burying the subsiding hummocks. For Dive 91, we1 used a MS2000 high-resolution multi-beam bathymetry echo-sounder on Isis flying at an altitude of 100m above the seafloor; to construct a bathymetry map with a vertical resolution of 20cm and a horizontal precision of 5m over an area of ˜3km2. The high-resolution bathymetry allows us to deduce that volcano dimensions average around 300m diameter, ˜150m altitude, and 0.005km3 volume and to count ˜100 volcanoes. Visual observations using the camera systems on Isis showed that individual volcanoes are essentially piles of pillow lavas, usually ˜1m diameter and >2m long of various types, sometimes leaving >10% gaps between pillows, sometimes interlocking somewhat deformed pillows. Small protrusions, 10-50cm long, which are numerous on some pillows, could be fairly easily broken off using the pincers on the hydraulic arms of Isis, and returned to the surface. Uncertainty remains

  20. Stable isotope compositions and water contents of boninite series volcanic rocks from Chichi-jima, Bonin Islands, Japan

    Science.gov (United States)

    Dobson, P.F.; O'Neil, J.R.

    1987-01-01

    Measurements of stable isotope compositions and water contents of boninite series volcanic rocks from the island of Chichi-jima, Bonin Islands, Japan, confirm that a large amount (1.6-2.4 wt.%) of primary water was present in these unusual magmas. An enrichment of 0.6??? in 18O during differentiation is explained by crystallization of 18O-depleted mafic phases. Silicic glasses have elevated ??18O values and relatively low ??D values indicating that they were modified by low-temperature alteration and hydration processes. Mafic glasses, on the other hand, have for the most part retained their primary isotopic signatures since Eocene time. Primary ??D values of -53 for boninite glasses are higher than those of MORB and suggest that the water was derived from subducted oceanic lithosphere. ?? 1987.

  1. Synthesis of ultrapure ZBLAN glass for laser refrigeration

    Science.gov (United States)

    Hehlen, Markus P.; Epstein, Richard I.; Patterson, Wendy M.

    2008-02-01

    The fluorozirconate glass ZBLAN:1%Yb 3+ was synthesized, for the first time, from fluoride precursors that were individually purified by solvent extraction and hydrofluoric (HF) gas treatment. The synthesis used aqueous solutions of high-purity commercial precursors that were subjected to ultra-filtration followed by solvent extraction using ammonium pyrrolidine dithiocarbamate (APDC) and methyl-isobutyl-ketone (MIBK). The purified metal fluorides were precipitated and treated in hot HF gas to remove water, hydroxyl (OH-), and oxide impurities. ZBLAN:1%Yb 3+ was fabricated from these precursors by melting under inert atmosphere, yielding glasses with excellent mechanical properties and having a clear, bubble-free, and crystallite-free matrix. The effect of adding 0.5 mol% of In 3+ as an oxidizer to suppress the reduction of Zr 4+ and the accompanying formation of black precipitates was studied. We found evidence for an oxidizer concentration threshold of ~0.8 mol%. Glasses made from purified fluorides formed black precipitates even with the addition of 0.5 mol% In 3+, while glasses made from commercial fluorides did not. In the latter, additional oxidizers were likely present in the form of transition-metal impurities. An In 3+ oxidizer concentration of >0.8 mol% is expected to eliminate the black precipitates in purified glasses and to yield ZBLAN:Yb 3+ glass for efficient laser cooling.

  2. Role of volcanism in climate and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Axelrod, D.I.

    1981-01-01

    Several major episodes of Tertiary explosive volcanism coincided with sharply lowered temperature as inferred from oxygen-isotope composition of foraminiferal tests in deep-sea cores. At these times, fossil floras in the western interior recorded significant changes. Reductions in taxa that required warmth occurred early in the Paleogene. Later, taxa that demand ample summer rain were reduced during a progressive change reflecting growth of the subtropic high. Other ecosystem changes that appear to have responded to volcanically induced climatic modifications include tachytely in Equidae (12 to 10 m.y. B.P.), rapid evolution of grasses (7 to 5 m.y. B.P.), evolution of marine mammals, and plankton flucuations. Although Lake Cretaceous extinctions commenced as epeiric seas retreated, the pulses of sharply lowered temperature induced by explosive volcanism, together with widespread falls of volcanic ash, may have led to extinction of dinosaurs, ammonites, cycadeoids, and other Cretaceous taxa. earlier, as Pangaea was assembled, Permian extinctions resulted not only from the elimination of oceans, epeiric seas, and shorelines, and the spread of more-continental climates, bu also from the climatic effects of major pulses of global volcanism and Gondwana glaciation.

  3. Spectral properties of Martian and other planetary glasses and their detection in remotely sensed data

    Science.gov (United States)

    Cannon, Kevin M.; Mustard, John F.; Parman, Stephen W.; Sklute, Elizabeth C.; Dyar, M. Darby; Cooper, Reid F.

    2017-01-01

    Thirty silicate glasses were synthesized as realistic analogs to those expected to exist on Mars, the Moon, and Mercury. Samples were measured using visible/near-infrared and Mössbauer spectroscopy to determine the effects of varying bulk chemistry, oxygen fugacity, and temperature on spectral properties. For Martian glasses, the fO2 during fusion strongly affects absorption band intensities in the spectra, while bulk chemistry has noticeable secondary effects on absorption band positions. Titanium and iron content drive spectral changes in lunar glasses, where Fe3+ is effectively absent. Iron-free Mercury analog glasses have much higher albedos than all other samples, and their spectral shape is a close match to some pyroclastic deposits on Mercury. Synthetic glass spectra were used as inputs into a spectral unmixing model applied to remote orbital datasets to test for the presence of glass. The model is validated against physical laboratory mixture spectra, as well as previous detections of glass-rich pyroclastic deposits on the Moon. Remote data were then used from suspected impact deposits and possible pyroclastic deposits on Mars as a new application of the model: the results reveal spatially coherent glass-rich material, and the strong spectral match of the synthetic glasses to these remotely sensed data gives new insights into the presence and character of glasses on the Martian surface. The large library of glass spectra generated here, acquired from consistently synthesized and measured samples, can serve as a resource for further studies of volcanic and impact processes on planetary bodies.

  4. Foam Glass for Construction Materials

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund

    2016-01-01

    Foaming is commonly achieved by adding foaming agents such as metal oxides or metal carbonates to glass powder. At elevated temperature, the glass melt becomes viscous and the foaming agents decompose or react to form gas, causing a foamy glass melt. Subsequent cooling to room temperature, result...... in a solid foam glass. The foam glass industry employs a range of different melt precursors and foaming agents. Recycle glass is key melt precursors. Many parameters influence the foaming process and optimising the foaming conditions is very time consuming. The most challenging and attractive goal is to make...... low density foam glass for thermal insulation applications. In this thesis, it is argued that the use of metal carbonates as foaming agents is not suitable for low density foam glass. A reaction mechanism is proposed to justify this result. Furthermore, an in situ method is developed to optimise...

  5. Determination of Trace and Volatile Element Abundance Systematics of Lunar Pyroclastic Glasses 74220 and 15426 Using LA-ICP-MS

    Science.gov (United States)

    McIntosh, E. Carrie; Porrachia, Magali; McCubbin, Francis M.; Day, James M. D.

    2017-01-01

    Since their recognition as pyroclastic glasses generated by volcanic fire fountaining on the Moon, 74220 and 15426 have garnered significant scientific interest. Early studies recognized that the glasses were particularly enriched in volatile elements on their surfaces. More recently, detailed analyses of the interiors of the glasses, as well as of melt inclusions within olivine grains associated with the 74220 glass beads, have determined high H2O, F, Cl and S contents. Such elevated volatile contents seem at odds with evidence from moderately volatile elements (MVE), such as Zn and K, for a volatile- depleted Moon. In this study, we present initial results from an analytical campaign to study trace element abundances within the pyroclastic glass beads. We report trace element data determined by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for 15426 and 74220.

  6. Geothermal surveys in the oceanic volcanic island of Mauritius

    Science.gov (United States)

    Verdoya, Massimo; Chiozzi, Paolo; Pasqua, Claudio

    2017-04-01

    Oceanic island chains are generally characterised by young volcanic systems that are predominately composed of basaltic lavas and related magmatic products. Although hot springs are occasionally present, the pervasive, massive, recent outpourings of basaltic lavas are the primary manifestation of the existence of geothermal resources. These islands may have, in principle, significant potential for the exploitation of geothermal energy. In this paper, we present results of recent investigations aimed at the evaluation of geothermal resources of the island of Mauritius, that is the emerging portion of a huge submarine, aseismic, volcanic plateau extending in the SW part of the Indian Ocean. The plateau is related to a long-lived hotspot track, whose present-day expression is the active volcano of La Réunion Island, located about 200 km SW of Mauritius. The island does not show at present any volcanic activity, but magmatism is quite recent as it dates from 7.8 to 0.03 Myr. Geochemical data from water samples collected from boreholes do not indicate the presence of mature water, i.e. circulating in high-temperature geothermal reservoirs, and argue for short-term water-rock interaction in shallow hydrogeological circuits. However, this cannot rule out that a deep magmatic heat source, hydraulically insulated from shallow aquifers, may occur. To evaluate the geothermal gradient, a 270-m-deep hole was thus drilled in the island central portion, in which the most recent volcanic activity (0.03 Myr) took place. Temperature-depth profiles, recorded after complete thermal equilibration, revealed a thermal gradient of 40 mK/m. Attempts of extracting additional thermal information were also made by measuring the temperature in a 170-m-deep deep water hole, no longer used. The results were consistent with the gradient hole, i.e. pointing to a weak or null deep-seated thermal anomaly beneath Mauritius and low geothermal potential. The deep thermal process (mantle plume) invoked

  7. Petrology and petrogenesis of the Eocene Volcanic rocks in Yildizeli area (Sivas), Central Anatolia, Turkey

    Science.gov (United States)

    Doğa Topbay, C.; Karacık, Zekiye; Genç, S. Can; Göçmengil, Gönenç

    2015-04-01

    Yıldızeli region to the south of İzmir Ankara Erzincan suture zone is situated on the large Sivas Tertiary sedimentary basin. After the northern branch of the Neotethyan Ocean was northerly consumed beneath the Sakarya Continent, a continent - continent collision occurred between the Anatolide- Tauride platform and Pontides and followed a severe intermediate magmatism during the Late Cretaceous- Tertiary period. This created an east-west trending volcanic belt along the whole Pontide range. In the previous studies different models are suggested for the Eocene volcanic succession such as post-collisional, delamination and slab-breakoff models as well as the arc model for its westernmost parts. We will present our field and geochemical data obtained from the Yıldızeli and its surroundings for its petrogenesis, and will discuss the tectonic model(s) on the basis of their geochemical/petrological aspects. Cenozoic volcanic sequences of Yıldızeli region which is the main subject of this study, overlie Pre-Mesozoic crustal meta-sedimentary group of Kırşehir Massif, Ophiolitic mélange and Cretaceous- Paleocene? flysch-like sequences. In the northern part of Yıldızeli region, north vergent thrust fault trending E-W seperates the ophiolitic mélange complex from the Upper Cretaceous-Paleocene and Tertiary formations. Volcano-sedimentary units, Eocene in age, of the Yıldızeli (Sivas-Turkey) which are intercalated with sedimentary deposits related to the collision of Anatolide-Tauride and a simultaneous volcanic activity (i.e. the Yıldızeli volcanics), exposed throughout a wide zone along E-W orientation. Yıldızeli volcanics consist of basalts, basaltic-andesites and andesitic lavas intercalated flow breccias and epiclastic, pyroclastic deposits. Basaltic andesite lavas contain Ca-rich plagioclase + clinopyroxene ± olivine with minor amounts of opaque minerals in a matrix comprised of microlites and glass; andesitic lavas are generally contain Ca

  8. Shattering women's glass ceiling

    OpenAIRE

    Camilleri Podesta, Marie Therese; Duca, Edward

    2013-01-01

    The role of women in academia has always greatly interested me. Several years ago, when I was asked to become Gender Issues Committee chairperson at the University of Malta, I readily accepted. http://www.um.edu.mt/think/shattering-womens-glass-ceiling/

  9. Glass as matter

    DEFF Research Database (Denmark)

    Beim, Anne

    2000-01-01

    Refraiming the Moderns - Substitute Windows and Glass. In general terms, the seminar has contributed to the growing interest in the problems concerning the restoration of Modern Movement architecture. More particularly, it has of course drawn our attention to modern windows, which are increasingly...

  10. What Glass Ceiling?

    Science.gov (United States)

    Lynch, Michael; Post, Katherine

    1996-01-01

    A recent study drawing on data from the Census Bureau and the Bureau of Labor Statistics suggests that the wage gap between men and women has virtually disappeared, and that the so-called "glass ceiling" results more from age and qualifications than from explicit discrimination. (SLD)

  11. Supercooled Liquids and Glasses

    OpenAIRE

    1999-01-01

    In these lectures, which were presented at "Soft and Fragile Matter, Nonequilibrium Dynamics, Metastability and Flow" University of St. Andrews, 8 July - 22 July, 1999, I give an introduction to the physics of supercooled liquids and glasses and discuss some computer simulations done to investigate these systems.

  12. Microchips on glass

    NARCIS (Netherlands)

    Keulemans, M.

    2007-01-01

    Microchips on glass. What about a mobile phone that uses a single microchip to receive all the available frequency bands, plus extras such as television, gps, and Internet access? Or, in due time, see-though implants that will monitor your state of health, and equipment that will let you see through

  13. Stained Glass and Flu

    Centers for Disease Control (CDC) Podcasts

    2017-02-01

    Dr. Robert Webster, an Emeritus member of the Department of Infectious Diseases at St. Jude Children's Research Hospital, discusses his cover art story on stained glass and influenza.  Created: 2/1/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/1/2017.

  14. Triad ''Metal - Enamel - Glass''

    Science.gov (United States)

    Mukhina, T.; Petrova, S.; Toporova, V.; Fedyaeva, T.

    2014-10-01

    This article shows how to change the color of metal and glass. Both these materials are self-sufficient, but sometimes used together. For example, enameling. In this case, the adhesion between metal substrate and stekloobraznae enamel layer, which was conducted on a stretching and a bend, was tested.

  15. Glass ceilings of professionalisation.

    Science.gov (United States)

    Stott, Dawn L

    2016-04-01

    The term glass ceiling is a political term often used to describe an unbreakable barrier that isnot visible with the human eye, but it keeps minorities from rising up i.e. it is a barrier to minoritygroups, in the past (and sometimes still) for women, that stops them from achieving theirtrue potential.

  16. Stained-Glass Pastels

    Science.gov (United States)

    Laird, Shirley

    2009-01-01

    The author has always liked the look of stained-glass windows. Usually the designs are simplified and the shapes are easier for younger students to draw. This technique seemed to be the perfect place for her fifth-graders to try their hand at color mixing. The smaller spaces and simple shapes were just what she needed for this group. Her students…

  17. Stained Glass and Flu

    Centers for Disease Control (CDC) Podcasts

    2016-02-01

    Dr. Robert Webster, an Emeritus member of the Department of Infectious Diseases at St. Jude Children's Research Hospital, discusses his cover art story on stained glass and influenza.  Created: 2/1/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/1/2016.

  18. "Stained Glass" Landscape Windows

    Science.gov (United States)

    Vannata, Janine

    2008-01-01

    Both adults and children alike marvel at the grand vivid stained-glass windows created by American artist Louis Comfort Tiffany. Today he is commonly recognized as one of America's most influential designers and artists throughout the last nineteenth and early twentieth century. In the lesson described in this article, students created their own…

  19. National volcanic ash operations plan for aviation

    Science.gov (United States)

    ,; ,

    2007-01-01

    The National Aviation Weather Program Strategic Plan (1997) and the National Aviation Weather Initiatives (1999) both identified volcanic ash as a high-priority informational need to aviation services. The risk to aviation from airborne volcanic ash is known and includes degraded engine performance (including flameout), loss of visibility, failure of critical navigational and operational instruments, and, in the worse case, loss of life. The immediate costs for aircraft encountering a dense plume are potentially major—damages up to $80 million have occurred to a single aircraft. Aircraft encountering less dense volcanic ash clouds can incur longer-term costs due to increased maintenance of engines and external surfaces. The overall goal, as stated in the Initiatives, is to eliminate encounters with ash that could degrade the in-flight safety of aircrews and passengers and cause damage to the aircraft. This goal can be accomplished by improving the ability to detect, track, and forecast hazardous ash clouds and to provide adequate warnings to the aviation community on the present and future location of the cloud. To reach this goal, the National Aviation Weather Program established three objectives: (1) prevention of accidental encounters with hazardous clouds; (2) reduction of air traffic delays, diversions, or evasive actions when hazardous clouds are present; and (3) the development of a single, worldwide standard for exchange of information on airborne hazardous materials. To that end, over the last several years, based on numerous documents (including an OFCMsponsored comprehensive study on aviation training and an update of Aviation Weather Programs/Projects), user forums, and two International Conferences on Volcanic Ash and Aviation Safety (1992 and 2004), the Working Group for Volcanic Ash (WG/VA), under the OFCM-sponsored Committee for Aviation Services and Research, developed the National Volcanic Ash Operations Plan for Aviation and Support of the

  20. Yesterday's Trash Makes Tomorrow's "Glass"

    Science.gov (United States)

    Wayne, Dale

    2010-01-01

    In this article, the author describes a glass art project inspired by Dale Chihuly. This project uses two-liter plastic soda bottles which are cut apart and trimmed. Applying heat using a hair dryer, the plastic curls and takes an uneven blown-glass quality. The "glass" is then painted using acrylic paint. (Contains 2 resources and 1 online…

  1. Yesterday's Trash Makes Tomorrow's "Glass"

    Science.gov (United States)

    Wayne, Dale

    2010-01-01

    In this article, the author describes a glass art project inspired by Dale Chihuly. This project uses two-liter plastic soda bottles which are cut apart and trimmed. Applying heat using a hair dryer, the plastic curls and takes an uneven blown-glass quality. The "glass" is then painted using acrylic paint. (Contains 2 resources and 1 online…

  2. Molecular Mobility in Sugar Glasses

    NARCIS (Netherlands)

    Dries, van den I.J.

    2000-01-01

    Glasses are liquids that exhibit solid state behavior as a result of their extremely high viscosity. Regarding their application to foods, glasses play a role in the preservation of foods, due to their high viscosity and the concomitant low molecular mobility. This thesis focuses on sugar glasses. S

  3. Glass for Solid State Devices

    Science.gov (United States)

    Bailey, R. F.

    1982-01-01

    Glass film has low intrinsic compressive stress for isolating active layers of magnetic-bubble and other solid-state devices. Solid-state device structure incorporates low-stress glasses as barrier and spacer layers. Glass layers mechanically isolate substrate, conductor, and nickel/iron layers.

  4. Sintering and foaming of barium silicate glass powder compacts

    Science.gov (United States)

    Mueller, Ralf; Reinsch, Stefan; Agea-Blanco, Boris

    2016-10-01

    The manufacture of sintered glasses and glass-ceramics, glass matrix composites and glass-bounded ceramics or pastes is often affected by gas bubble formation. Against this background, we studied sintering and foaming of barium silicate glass powders used as SOFC sealants using different powder milling procedures. Sintering was measured by means of heating microscopy backed up by XPD, DTA, Vacuum Hot Extraction (VHE) and optical and electron microscopy. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the powder compacts were uniaxially pressed and sintered in air, the milling atmosphere sig¬ni¬ficantly affected foaming. The strength of this effect increased in the order Ar ? N2 encapsulated CO2, even for powders milled in Ar and N2. Results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. Foaming could be substantially reduced by milling in water and 10 wt% HCl.

  5. Sintering and foaming of barium silicate glass powder compacts

    Directory of Open Access Journals (Sweden)

    Ralf Mueller

    2016-10-01

    Full Text Available The manufacture of sintered glasses and glass-ceramics, glass matrix composites and glass-bounded ceramics or pastes is often affected by gas bubble formation. Against this background, we studied sintering and foaming of barium silicate glass powders used as SOFC sealants using different powder milling procedures. Sintering was measured by means of heating microscopy backed up by XPD, DTA, Vacuum Hot Extraction (VHE and optical and electron microscopy. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the powder compacts were uniaxially pressed and sintered in air, the milling atmosphere sig¬ni¬ficantly affected foaming. The strength of this effect increased in the order Ar  N2 < air < CO2. Conformingly, VHE studies revealed that the pores of foamed samples predominantly encapsulated CO2, even for powders milled in Ar and N2. Results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. Foaming could be substantially reduced by milling in water and 10 wt% HCl.

  6. gPark: Vehicle Parking Management System Using Smart Glass

    Directory of Open Access Journals (Sweden)

    Rana E. Ahmed

    2016-01-01

    Full Text Available Recent advances in wearable technologies have opened new avenues for their applications in various fields. This paper presents the design, implementation, and testing results for a vehicle parking management system using smart Glass technology. The management system consists of four major interconnected applications. The most important one, running on the smart Glass, scans the vehicle number plate and extracts the related information in real time. The vehicle information is sent to the remote server for checking of any violation. The server sends the updates back to the Glass that allows the parking attendant to take further actions, if needed. The system was tested in real-life scenarios, and it was found that the detection accuracy up to 75% can be easily achieved with current hardware and software capabilities of the Google Glass.

  7. Ozone depletion following future volcanic eruptions

    Science.gov (United States)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  8. Spain as an emergency air traffic hub during volcanic air fall events? Evidence of past volcanic ash air fall over Europe during the late Pleistocene

    Science.gov (United States)

    Hardiman, Mark; Lane, Christine; Blockley, Simon P. E.; Moreno, Ana; Valero-Garcés, Blas; Ortiz, José E.; Torres, Trino; Lowe, John J.; Menzies, Martin A.

    2010-05-01

    Past volcanic eruptions often leave visible ash layers in the geological record, for example in marine or lake sedimentary sequences. Recent developments, however, have shown that non-visible volcanic ash layers are also commonly preserved in sedimentary deposits. These augment the record of past volcanic events by demonstrating that past ash dispersals have been more numerous and widely disseminated in Europe than previously appreciated. The dispersal ‘footprints' of some large late Pleistocene European eruptions are examined here in the light of the recent Eyjafjallajökull eruption. For example, the Vedde Ash which was erupted from Iceland around 12 thousand years ago, delivered distal (and non-visible) glass deposits as far south as Switzerland and as far east as the Ural Mountains in Russia, with an overall European distribution remarkably similar to the dominant tracks of the recent Eyjafjallajökull plumes. The Eyjafjallajökull eruption has demonstrated that relatively small amounts of distal volcanic ash in the atmosphere can seriously disrupt aviation activity, with attendant economic and other consequences. It has raised fundamental questions about the likelihood of larger or more prolonged volcanic activity in the near future, and the possibility of even more serious consequences than those experienced recently. Given that there are several other volcanic centres that could cause such disruption in Europe (e.g. Campania and other volcanic centres in Italy; Aegean volcanoes), a key question is whether there are parts of Europe less prone to ash plumes and which could therefore operate as emergency air traffic hubs during times of ash dispersal. Although not generated to answer this question, the recent geological record might provide a basis for seeking the answer. For example, four palaeo-records covering the time frame of 8 - 40 Ka BP that are geographically distributed across Spain have been examined for non-visible distal ash content. All four have

  9. Monitoring of the volcanic plume based on the post-fit phase residual of PPP analysis and SNR data

    Science.gov (United States)

    Ohta, Yusaku; Iguchi, Masato

    2016-04-01

    A volcanic explosion is one of the largest energy-release phenomena on earth. For example, vulcanian eruptions usually eject large amounts of rock mass, tephra, and volcanic ash. Ash fall from such events can seriously affect the structural integrity of buildings, in addition to disrupting land and air traffic. Therefore, the monitoring and prediction of ash fall is very important. In this study, using data from a dense GNSS network, we investigated the spatiotemporal development of the volcanic plume ejected by the vulcanian eruption in Sakurajima, southwestern Japan on July 24, 2012. We extracted the post-fit phase residuals (PPR) of ionosphere-free linear combinations for each satellite based on the precise point positioning approach. Temporal and spatial PPR anomalies clearly detected the movement of the volcanic plume. The maximum height of the crossing points of anomalous PPR paths was determined to be approximately 4000 m. We then compared the PPR with the signal-to-noise ratio (SNR) anomalies. Only the path passing just above the crater showed significant change in the SNR value, suggesting that the volcanic ash and the water vapor within the volcanic plume became separated after reaching a high altitude because of ash fall during the plume's lateral movement. In the presentation, we will introduce the eruption in Shin-dake (Kuchinoerabu island, southwestern Japan) on May 29, 2015 based on the SNR data.

  10. Tropical Volcanic Soils From Flores Island, Indonesia

    Directory of Open Access Journals (Sweden)

    Hikmatullah

    2010-01-01

    Full Text Available Soils that are developed intropical region with volcanic parent materials have many unique properties, and high potential for agricultural use.The purpose of this study is to characterize the soils developed on volcanic materials from Flores Island, Indonesia,and to examine if the soils meet the requirements for andic soil properties. Selected five soils profiles developed fromandesitic volcanic materials from Flores Island were studied to determine their properties. They were compared intheir physical, chemical and mineralogical characteristics according to their parent material, and climatic characteristicdifferent. The soils were developed under humid tropical climate with ustic to udic soil moisture regimes withdifferent annual rainfall. The soils developed from volcanic ash parent materials in Flores Island showed differentproperties compared to the soils derived from volcanic tuff, even though they were developed from the sameintermediary volcanic materials. The silica contents, clay mineralogy and sand fractions, were shown as the differences.The different in climatic conditions developed similar properties such as deep solum, dark color, medium texture, andvery friable soil consistency. The soils have high organic materials, slightly acid to acid, low to medium cationexchange capacity (CEC. The soils in western region have higher clay content and showing more developed than ofthe eastern region. All the profiles meet the requirements for andic soil properties, and classified as Andisols order.The composition of sand mineral was dominated by hornblende, augite, and hypersthenes with high weatherablemineral reserves, while the clay fraction was dominated by disordered kaolinite, and hydrated halloysite. The soilswere classified into subgroup as Thaptic Hapludands, Typic Hapludands, and Dystric Haplustands

  11. Ages of plains volcanism on Mars

    Science.gov (United States)

    Hauber, Ernst; Jagert, Felix; Broz, Petr

    2010-05-01

    Plain-style volcanism [1] is widespread in the Tharsis and Elysium volcanic provinces on Mars, [2,3]. Detailed images and topographic data reveal the morphology and topography of clusters of low shields and associated lava flows. The landforms of plains volcanism on Mars have all well-known terrestrial analogues in basaltic volcanic regions, such as Hawaii, Iceland, and in particular the Snake River Plains [4]. The very gentle flank slopes (Ga - 2.9 Ga). Our results indicate that Late Amazonian volcanism is more widespread in Tharsis than previously recognized. Based on our results it appears possible that Mars is volcanologically not dead yet. Ongoing work investigates the volumes of erupted products and implications for the outgassing history and atmospheric evolution of Mars. [1] Greeley R. (1982) JGR 87, 2705-2712. [2] Plescia J. (1981) Icarus, 45, 586-601. [3] Hodges C.A. and Moore H.J. (1994) Atlas of volcanic features on Mars: USGS Prof. Paper 1534, 194 p. [4] Hauber E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 69-95. [5] Wilson L. et al. (2009) J. Volcanol. Geotherm. Res. 185, 28-46. [6] Vaucher, J. et al. (2009) Icarus 204, 418-442. [7] Baratoux D. et al. (2009) J. Volcanol. Geotherm. Res. 185, 47-68. [8] Bleacher J.E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 96-102. [9] Ivanov B.A. (2001) Space Sci. Rev. 96, 87-104. [10] Hartmann W.H. and Neukum G. (2001) Space Sci. Rev. 96, 165-194 [11] Kneissl T. et al. (2010) LPS XVI, submitted. [12] Michael, G.G. and Neukum G. (2010) Earth Planet. Sci. Lett., in press. . [13] Malin M.C. et al. (2007) JGR 112, E05S04, doi: 10.1029/2006JE002808.

  12. Osmium isotopes and highly siderophile elements in lunar glasses

    Science.gov (United States)

    Horan, M.; Walker, R.; Shearer, C.; Papike, J.

    2003-04-01

    The absolute and relative abundances of the highly siderophile elements (HSE) present in planetary mantles are primarily controlled by silicate-metal partitioning during core-mantle differentiation and by later planetary accretion. Constraints on HSE distributions in the lunar mantle will provide insights to the formation and late accretionary history of not only the Moon, but also Earth. Because no samples of the lunar mantle have been collected, the only materials presently available for constraining mantle abundances are lunar volcanic rocks. The Apollo 15 green and Apollo 17 orange glasses are spherules derived from fire-fountain eruptions of mare basalts. These glasses are more primitive than the mare basalts, and probably were derived by the melting of cumulate assemblages from the lunar magma ocean in the deep interior (> 400 km). Despite our limited understanding of mantle-melt partitioning of the HSE, even for terrestrial systems, these glasses provide the best hope for constraining the HSE composition of the lunar interior. We report Os isotopic composition data and Re, Os, Ir, Ru, Pt and Pd isotope dilution concentration data for green glass (15426,164) and orange glass (74001,1217). Absolute and relative abundances of HSE are variable. The green glass has elemental ratios of the HSE and an Os isotopic composition within the range defined by chondritic meteorites, suggesting that the HSE were dominated by a meteoritic contaminant. This sample probably provides little information about the lunar interior, but may help constrain the types of meteorites impacting the lunar surface. Two size fractions (180-325 mesh and 75-180 mesh) of the orange glass were analyzed. HSE patterns for both size fractions are fractionated, having higher chondrite-normalized abundances of Pt and Pd, compared with Os and Ir. The supra-chondritic 187Os/188Os ratio (0.1339) of the finer fraction indicates modestly fractionated Re/Os relative to chondritic. The coarser size fraction

  13. Constraining the onset of flood volcanism in Isle of Skye Lava Field, British Paleogene Volcanic Province

    Science.gov (United States)

    Angkasa, Syahreza; Jerram, Dougal. A.; Svensen, Henrik; Millet, John M.; Taylor, Ross; Planke, Sverre

    2016-04-01

    In order to constrain eruption styles at the onset of flood volcanism, field observations were undertaken on basal sections of the Isle of Skye Lava Field, British Paleogene Volcanic Province. This study investigates three specific sections; Camus Ban, Neist Point and Soay Sound which sample a large area about 1500 km2 and can be used to help explain the variability in palaeo-environments at the onset of flood volcanism. Petrological analysis is coupled with petrophysical lab data and photogrammetry data to create detailed facies models for the different styles of initiating flood basalt volcanism. Photogrammetry is used to create Ortho-rectified 3D models which, along with photomontage images, allow detailed geological observations to be mapped spatially. Petrographic analyses are combined with petrophysical lab data to identify key textural variation, mineral compositions and physical properties of the volcanic rocks emplaced during the initial eruptions. Volcanism initiated with effusive eruptions in either subaerial or subaqueous environments resulting in tuff/hyaloclastite materials or lava flow facies lying directly on the older Mesozoic strata. Volcanic facies indicative of lava-water interactions vary significantly in thickness between different sections suggesting a strong accommodation space control on the style of volcanism. Camus Ban shows hyaloclastite deposits with a thickness of 25m, whereas the Soay Sound area has tuffaceous sediments of under 0.1m in thickness. Subaerial lavas overly these variable deposits in all studied areas. The flood basalt eruptions took place in mixed wet and dry environments with some significant locally developed water bodies (e.g. Camus Ban). More explosive eruptions were promoted in some cases by interaction of lavas with these water bodies and possibly by local interaction with water - saturated sediments. We record key examples of how palaeotopography imparts a primary control on the style of volcanism during the

  14. Volcanic Pipe of the Namuaiv Mountain

    Directory of Open Access Journals (Sweden)

    Vladimir K. Karzhavin

    2011-12-01

    Full Text Available This research was aimed at reconstructing thermodynamic conditions required for the studied mineral assemblages to be created and exist in nature. The results of the investigations confirm to the recent ideas about an important, even leading, role of temperature, pressure and dioxide carbon in diamond formation in volcanic pipers. The results of this theoretical research allows assuming that one of the reasons for the absence of diamonds in the Namuaiv Mountain volcanic pipe may lie in the increased content of water and oxidizing environmental conditions of their formation

  15. Volcanic Eruptions and Climate: Outstanding Research Issues

    Science.gov (United States)

    Robock, Alan

    2016-04-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. Based on observations after major eruptions of the past and experiments with numerical models of the climate system, we understand much about their climatic impact, but there are also a number of unanswered questions. Volcanic eruptions produce global cooling, and are an important natural cause of interannual, interdecadal, and even centennial-scale climate change. One of the most interesting volcanic effects is the "winter warming" of Northern Hemisphere continents following major tropical eruptions. During the winter in the Northern Hemisphere following every large tropical eruption of the past century, surface air temperatures over North America, Europe, and East Asia were warmer than normal, while they were colder over Greenland and the Middle East. This pattern and the coincident atmospheric circulation correspond to the positive phase of the Arctic Oscillation. While this response is observed after recent major eruptions, most state-of-the-art climate models have trouble simulating winter warming. Why? High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. Both tropical and high latitude eruptions can weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade have had a small effect on global temperature trends. Some important outstanding research questions include: How much seasonal, annual, and decadal predictability is possible following a large volcanic eruption? Do

  16. Tellurium in active volcanic environments: Preliminary results

    Science.gov (United States)

    Milazzo, Silvia; Calabrese, Sergio; D'Alessandro, Walter; Brusca, Lorenzo; Bellomo, Sergio; Parello, Francesco

    2014-05-01

    Tellurium is a toxic metalloid and, according to the Goldschmidt classification, a chalcophile element. In the last years its commercial importance has considerably increased because of its wide use in solar cells, thermoelectric and electronic devices of the last generation. Despite such large use, scientific knowledge about volcanogenic tellurium is very poor. Few previous authors report result of tellurium concentrations in volcanic plume, among with other trace metals. They recognize this element as volatile, concluding that volcanic gases and sulfur deposits are usually enriched with tellurium. Here, we present some results on tellurium concentrations in volcanic emissions (plume, fumaroles, ash leachates) and in environmental matrices (soils and plants) affected by volcanic emissions and/or deposition. Samples were collected at Etna and Vulcano (Italy), Turrialba (Costa Rica), Miyakejima, Aso, Asama (Japan), Mutnovsky (Kamchatka) at the crater rims by using common filtration techniques for aerosols (polytetrafluoroethylene filters). Filters were both eluted with Millipore water and acid microwave digested, and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Volcanic ashes emitted during explosive events on Etna and Copahue (Argentina) were analyzed for tellurium bulk composition and after leaching experiments to evaluate the soluble fraction of tellurium. Soils and leaves of vegetation were also sampled close to active volcanic vents (Etna, Vulcano, Nisyros, Nyiragongo, Turrialba, Gorely and Masaya) and investigated for tellurium contents. Preliminary results showed very high enrichments of tellurium in volcanic emissions comparing with other volatile elements like mercury, arsenic, thallium and bismuth. This suggests a primary transport in the volatile phase, probably in gaseous form (as also suggested by recent studies) and/or as soluble salts (halides and/or sulfates) adsorbed on the surface of particulate particles and ashes. First

  17. Emplacement Scenarios for Volcanic Domes on Venus

    Science.gov (United States)

    Glaze, Lori S.; Baloga, Steve M.; Stofan, Ellen R.

    2012-01-01

    One key to understanding the history of resurfacing on Venus is better constraints on the emplacement timescales for the range of volcanic features visible on the surface. A figure shows a Magellan radar image and topography for a putative lava dome on Venus. 175 such domes have been identified with diameters ranging from 19 - 94 km, and estimated thicknesses as great as 4 km. These domes are thought to be volcanic in origin and to have formed by the flow of viscous fluid (i.e., lava) on the surface.

  18. Volcanic air pollution hazards in Hawaii

    Science.gov (United States)

    Elias, Tamar; Sutton, A. Jeff

    2017-04-20

    Noxious sulfur dioxide gas and other air pollutants emitted from Kīlauea Volcano on the Island of Hawai‘i react with oxygen, atmospheric moisture, and sunlight to produce volcanic smog (vog) and acid rain. Vog can negatively affect human health and agriculture, and acid rain can contaminate household water supplies by leaching metals from building and plumbing materials in rooftop rainwater-catchment systems. U.S. Geological Survey scientists, along with health professionals and local government officials are working together to better understand volcanic air pollution and to enhance public awareness of this hazard.

  19. Volatile heavy metal mobility in silicate liquids: Implications for volcanic degassing and eruption prediction

    Science.gov (United States)

    MacKenzie, Jason M.; Canil, Dante

    2008-05-01

    The volatilization of Cd, Re, Tl, Pb, Sb and Te from melts in the system CaO-MgO-Al 2O 3-SiO 2 (CMAS) and Na 2O-MgO-Al 2O 3-SiO 2 (NMAS) has been investigated at 0.1 MPa and 1200-1350 °C. Experiments were conducted in air using metal-doped melts in Pt crucibles. Analysis of quenched glasses by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) normal to the melt/gas interface produced concentration profiles for Cd, Re, Tl, Pb, Sb and Te to which a semi-infinite one-dimensional diffusion model could be applied to extract diffusion coefficients ( D). The melt was also doped with Cu, Zn, In, Mo, Sn and W but concentration profiles for these metals did not develop. In the CMAS composition at 1300 °C, the fastest diffusing element was Cd having a log DCd = - 6.5 ± 0.2. The slowest element was Re with log DRe = - 7.5 ± 0.3. Diffusivities of Sb, Te, Pb and Tl have intermediate values where log DSb = - 7.1 ± 0.1, log DTe = - 7.2 ± 0.3, log DPb = - 7.1 ± 0.2, log DTl = - 7.0 ± 0.2 cm 2/s. In the NMAS composition, log DRe = - 6.5 ± 0.2, log DSb = - 6.0 ± 0.2, log DPb = - 6.1 ± 0.1, log DTl = - 5.8 ± 0.2 cm 2/s (values for Cd and Te were not determined). Differences in diffusivity of volatile heavy metal ions to a melt-gas interface lead to significant fractionation between these metals in magmas during degassing. Given the observed differences in Cd and Re diffusivities in the CMAS composition, we predict an increase in the normalized Cd/Re ratio in the gas phase with increasing bubble growth rate. Monitoring of the Cd/Re ratios in aerosols from degassing volcanoes may provide a tool for predicting volcanic eruption.

  20. The ELSA tephra stack: Volcanic activity in the Eifel during the last 500,000 years

    Science.gov (United States)

    Förster, Michael W.; Sirocko, Frank

    2016-07-01

    Tephra layers of individual volcanic eruptions are traced in several cores from Eifel maar lakes, drilled between 1998 and 2014 by the Eifel Laminated Sediment Archive (ELSA). All sediment cores are dated by 14C and tuned to the Greenland interstadial succession. Tephra layers were characterized by the petrographic composition of basement rock fragments, glass shards and characteristic volcanic minerals. 10 marker tephra, including the well-established Laacher See Tephra and Dümpelmaar Tephra can be identified in the cores spanning the last glacial cycle. Older cores down to the beginning of the Elsterian, show numerous tephra sourced from Strombolian and phreatomagmatic eruptions, including the 40Ar/39Ar dated differentiated tephra from Glees and Hüttenberg. In total, at least 91 individual tephra can be identified since the onset of the Eifel volcanic activity at about 500,000 b2k, which marks the end of the ELSA tephra stack with 35 Strombolian, 48 phreatomagmatic and 8 tephra layers of evolved magma composition. Many eruptions cluster near timings of the global climate transitions at 140,000, 110,000 and 60,000 b2k. In total, the eruptions show a pattern, which resembles timing of phases of global sea level and continental ice sheet changes, indicating a relation between endogenic and exogenic processes.

  1. Petrogenesis of Quaternary Shoshonitic Volcanism in NE Iran (Ardabil: Implication for Postcollisional Magmatism

    Directory of Open Access Journals (Sweden)

    Habib Shahbazi Shiran

    2013-01-01

    Full Text Available Trachyandesites, trachytes, andesites, and pyrocalstic rocks, with shoshonitic signature, are the main Quaternary volcanic rocks in the Sabalan region (Ardabil. Plagiocalse, K-feldspar, biotite associated with clinopyroxene, and glass are the main constituents of these lavas. Plagioclases are andesine to labradorite while clinopyroxenes have augitic composition. The Sabalan volcanic rocks show enrichment in LREEs (relative to HREEs and are characterized by enrichment in LILEs and depletion in HFSEs. Petrological observations, along with rare earth and trace elements geochemistry, suggest shoshonitic signature for Sabalan lavas. This signature highlights derivation from a subduction-related source. The Sabalan volcanic rocks are isotopically characterized by derivation from an enriched mantle source with a tendency to plot in the fields defined by island-arc basalts (IAB and OIBs (in εNd versus 87Sr/86Sr diagram. The geochemical and isotopic characteristics of the Sabalan lavas suggest that their magma has been issued via low degree partial melting of a subduction-metasomatized continental lithospheric mantle. The formation of these lavas is related to slab steepening and breakoff in a postcollisional regime.

  2. Heliostat glass survey and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Lind, M. A.; Russin, J. M.

    1978-01-01

    The glass characterization and specification task included a comprehensive survey of both foreign and domestic sources of low distortion, low iron, .125 nominal flat glass for use in heliostat applications. PNL attempted to determine the availability of production lines, estimate industry interest, lead times, and costs for producing glass for second surface heliostat mirrors for the Barstow pilot plant and future commercial plants. Glass samples representative of the industry production capability were collected and characterized. The results of the survey and analysis were used to generate a specification for the Barstow Pilot Plant glass procurement.

  3. Vitrified hillforts as anthropogenic analogues for nuclear waste glasses - project planning and initiation

    Energy Technology Data Exchange (ETDEWEB)

    Sjoblom, Rolf; Weaver, Jamie L.; Peeler, David K.; Mccloy, John S.; Kruger, Albert A.; Ogenhall, E.; Hjarthner-Jolder, E.

    2016-09-27

    Nuclear waste must be deposited in such a manner that it does not cause significant impact on the environment or human health. In some cases, the integrity of the repositories will need to sustain for tens to hundreds of thousands of years. In order to ensure such containment, nuclear waste is frequently converted into a very durable glass. It is fundamentally difficult, however, to assure the validity of such containment based on short-term tests alone. To date, some anthropogenic and natural volcanic glasses have been investigated for this purpose. However, glasses produced by ancient cultures for the purpose of joining rocks in stonewalls have not yet been utilized in spite of the fact that they might offer significant insight into the long-term durability of glasses in natural environments. Therefore, a project is being initiated with the scope of obtaining samples and characterizing their environment, as well as to investigate them using a suite of advanced materials characterization techniques. It will be analysed how the hillfort glasses may have been prepared, and to what extent they have altered under in-situ conditions. The ultimate goals are to obtain a better understanding of the alteration behaviour of nuclear waste glasses and its compositional dependence, and thus to improve and validate models for nuclear waste glass corrosion. The paper deals with project planning and initiation, and also presents some early findings on fusion of amphibolite and on the process for joining the granite stones in the hillfort walls.

  4. Geomagnetic imprint of the Persani volcanism

    Science.gov (United States)

    Besutiu, Lucian; Seghedi, Ioan; Zlagnean, Luminita; Atanasiu, Ligia; Popa, Razvan-Gabriel; Pomeran, Mihai; Visan, Madalina

    2016-04-01

    The Persani small volume volcanism is located in the SE corner of the Transylvanian Depression, at the north-western edge of the intra-mountainous Brasov basin. It represents the south-easternmost segment of the Neogene-Quaternary volcanic chain of the East Carpathians. The alkaline basalt monogenetic volcanic field is partly coeval with the high-K calc-alkaline magmatism south of Harghita Mountains (1-1.6 Ma). Its eruptions post-dated the calc-alkaline volcanism in the Harghita Mountains (5.3-1.6 Ma), but pre-dated the high-K calc-alkaline emissions of Ciomadul volcano (1.0-0.03 Ma). The major volcanic forms have been mapped in previous geological surveys. Still, due to the small size of the volcanoes and large extent of tephra deposits and recent sediments, the location of some vents or other volcanic structures has been incompletely revealed. To overcome this problem, the area was subject to several near-surface geophysical investigations, including paleomagnetic research. However, due to their large-scale features, the previous geophysical surveys proved to be an inappropriate approach to the volcanological issues. Therefore, during the summers of 2014 and 2015, based on the high magnetic contrast between the volcanic rocks and the hosting sedimentary formations, a detailed ground geomagnetic survey has been designed and conducted, within central Persani volcanism area, in order to outline the presence of volcanic structures hidden beneath the overlying deposits. Additionally, information on the rock magnetic properties was also targeted by sampling and analysing several outcrops in the area. Based on the acquired data, a detailed total intensity scalar geomagnetic anomaly map was constructed by using the recent IGRF12 model. The revealed pattern of the geomagnetic field proved to be fully consistent with the direction of magnetisation previously determined on rock samples. In order to enhance the signal/noise ratio, the results were further processed by

  5. Temperature dependence of fluctuation time scales in spin glasses

    DEFF Research Database (Denmark)

    Kenning, Gregory G.; Bowen, J.; Sibani, Paolo;

    2010-01-01

    Using a series of fast cooling protocols we have probed aging effects in the spin glass state as a function of temperature. Analyzing the logarithmic decay found at very long time scales within a simple phenomenological barrier model, leads to the extraction of the fluctuation time scale of the s...

  6. Spectral properties of simulated impact glasses produced from martian soil analogue JSC Mars-1

    Science.gov (United States)

    Moroz, L. V.; Basilevsky, A. T.; Hiroi, T.; Rout, S. S.; Baither, D.; van der Bogert, C. H.; Yakovlev, O. I.; Fisenko, A. V.; Semjonova, L. F.; Rusakov, V. S.; Khramov, D. A.; Zinovieva, N. G.; Arnold, G.; Pieters, C. M.

    2009-07-01

    To simulate the formation of impact glasses on Mars, an analogue of martian bright soil (altered volcanic soil JSC Mars-1) was melted at relevant oxygen fugacities using a pulsed laser and a resistance furnace. Reduction of Fe3+ to Fe2+ and in some cases formation of nanophase Fe0 in the glasses were documented by Mössbauer spectroscopy and TEM studies. Reflectance spectra for several size fractions of the JSC Mars-1 sample and the glasses were acquired between 0.3 and 25 μm. The glasses produced from the JSC Mars-1 soil show significant spectral variability depending on the method of production and the cooling rate. In general, they are dark and less red in the visible compared to the original JSC Mars-1 soil. Their spectra do not have absorption bands due to bound water and structural OH, have positive spectral slopes in the near-infrared range, and show two broad bands centered near 1.05 and 1.9 μm, typical of glasses rich in ferrous iron. The latter bands and low albedo partly mimic the spectral properties of martian dark regions, and may easily be confused with mafic materials containing olivine and low-Ca pyroxene. Due to their disordered structures and vesicular textures, the glasses show relatively weak absorption features from the visible to the thermal infrared. These weak absorption bands may be masked by the stronger bands of mafic minerals. Positive near-infrared spectral slopes typical of fresh iron-bearing impact or volcanic glasses may be masked either by oxide/dust coatings or by aerosols in the Mars' atmosphere. As a result, impact glasses may be present on the surface of Mars in significant quantities that have been either misidentified as other phases or masked by phases with stronger infrared features. Spectrometers with sufficient spatial resolution and wavelength coverage may detect impact glasses at certain locations, e.g., in the vicinity of fresh impact craters. Such dark materials are usually interpreted as accumulations of mafic

  7. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

    This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

  8. Controls on the surface chemical reactivity of volcanic ash investigated with probe gases

    Science.gov (United States)

    Maters, Elena C.; Delmelle, Pierre; Rossi, Michel J.; Ayris, Paul M.; Bernard, Alain

    2016-09-01

    Increasing recognition that volcanic ash emissions can have significant impacts on the natural and human environment calls for a better understanding of ash chemical reactivity as mediated by its surface characteristics. However, previous studies of ash surface properties have relied on techniques that lack the sensitivity required to adequately investigate them. Here we characterise at the molecular monolayer scale the surfaces of ash erupted from Eyjafjallajökull, Tungurahua, Pinatubo and Chaitén volcanoes. Interrogation of the ash with four probe gases, trimethylamine (TMA; N(CH3)3), trifluoroacetic acid (TFA; CF3COOH), hydroxylamine (HA; NH2OH) and ozone (O3), reveals the abundances of acid-base and redox sites on ash surfaces. Measurements on aluminosilicate glass powders, as compositional proxies for the primary constituent of volcanic ash, are also conducted. We attribute the greater proportion of acidic and oxidised sites on ash relative to glass surfaces, evidenced by comparison of TMA/TFA and HA/O3 uptake ratios, in part to ash interaction with volcanic gases and condensates (e.g., H2O, SO2, H2SO4, HCl, HF) during the eruption. The strong influence of ash surface processing in the eruption plume and/or cloud is further supported by particular abundances of oxidised and reduced sites on the ash samples resulting from specific characteristics of their eruptions of origin. Intense interaction with water vapour may result in a higher fraction of oxidised sites on ash produced by phreatomagmatic than by magmatic activity. This study constitutes the first quantification of ash chemical properties at the molecular monolayer scale, and is an important step towards better understanding the factors that govern the role of ash as a chemical agent within atmospheric, terrestrial, aquatic or biotic systems.

  9. Volcanic degassing and secondary hydration of volcanic ash and scoria: Implications for paleoaltimetry and paleoclimate studies

    Science.gov (United States)

    Seligman, A. N.; Bindeman, I. N.

    2013-12-01

    scoria. We do not observe a trend between the SiO2 wt.% (51-56 wt.%) and the water content of the samples. The δD values (between -99 × 5.6 and -121 × 1.2 per mil are near equilibrium with local postglacial meteoric waters, when incorporating a -30‰ fractionation, and provide a trend between δD and wt.% H2O, where higher water concentrations are associated with lower δD values. We also report preliminary results of δ18O in extracted water, using experimentally hydrated dacite and rhyolite glass, and a large set of natural ash (ash described above and ash from the Lava Creek Tuff of Yellowstone). These results show water-glass fractionations between -11.5 and -12.7 for experimental glasses and -2.2 to -11.4 for natural ash. We are looking into using δ18Owater in glass as a more robust and retentive proxy of past environmental waters for paleoclimate and paleoaltimetry research.

  10. Production of glass or glass-ceramic to metal seals with the application of pressure

    Science.gov (United States)

    Kelly, M.D.; Kramer, D.P.

    1985-01-04

    In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.

  11. Volcanic processes recorded by inclusions in sanidine megacrystals ejected from Quaternary Rockeskyll volcano, Eifel, Germany

    Science.gov (United States)

    Eilhard, Nicole; Schreuer, Jürgen; Stöckhert, Bernhard

    2016-04-01

    Sanidine megacrystals were ejected by a late stage explosive eruption at the Quaternary Rockeskyll volcanic complex, Eifel volcanic field, Germany. The homogeneous distribution of barium (about 1 % wt BaO equivalent to about 2 mole % celsian component) indicates that the nearly perfect single crystals must have crystallized in the Ostwald-Miers range from a huge reservoir, probably in the roof of a magma chamber. Irregularities during crystal growth caused trapping of hydrous melt inclusions, which are the objective of the present study. The inclusions show a characteristic concentric microstructure, in the following described from the sanidine host towards the inclusion center: (1) Ba is enriched by a factor of 2 to 3 in a ca. 0.01 mm wide rim, compared to the otherwise homogeneous sanidine host; (2) inwards, the continuous rim is overgrown by a thin crust of Ba enriched sanidine with irregular surface; (3) a layer of glass with a composition similar to sanidine; (4) a second, thinner layer of glass slightly reduced in Na2O and K2O, separated from the first glass layer by a sharp interface with approximately spherical shape; (5) a bubble containing a fluid phase, composed of H2O and minor CO2. This record is interpreted as follows: After crystallization of the sanidine megacrystals, a rise in temperature within the magmatic system caused some re-melting of the Ba-rich sanidine around the inclusions. Partitioning of Ba between the small included melt reservoir and the host caused formation of the Ba-rich rim (layer 1) by diffusive exchange. The onset of cooling lead to crystallization of the thin sanidine crust (layer 2). Finally, very rapid decompression and cooling during the subsequent explosive eruption caused sequential phase separation (two stages) in the remaining melt, the denser melt phase (layers 3 and 4) quenched to glass, the complementary low-density volatile-rich phase forming the central bubble. In summary, the microstructure and phase composition of

  12. Mineralogy and trace element chemistry of the Siliceous Earth of Barmer basin, Rajasthan: Evidence for a volcanic origin

    Indian Academy of Sciences (India)

    M S Sisodia; U K Singh; G Lashkari; P N Shukla; A D Shukla; N Bhandari

    2005-04-01

    We report the presence of a 3-5 cm thick loose fragmental layer in the Siliceous Earth at Matti ka Gol in the Barmer basin of Rajasthan. Petrographic, chemical and mineralogical study reveals the presence of abundant volcanic debris such as glass shards, agglutinates, hollow spheroids, kinked biotites, feldspars showing oscillatory zoning, olivines, ilmenite and native iron. The presence of similar particles in the whole section suggests that the Siliceous Earth is a volcanic ash. Stratigraphic correlation, palynological and microvertebrate data suggest that the Siliceous Earth may have deposited over a short span of time during the Upper Cretaceous to Lower Palaeocene. In view of the possibility that this section may contain K/T impact debris, we looked for grains having impact signatures. Some patches of the Siliceous Earth of Bariyara show the presence of Ni-rich (< 0.5%) vesicular glasses, sanidine spherules, magnesioferrite crystals, soot, etc., but because of their low abundance, it is not possible to establish if they are volcanic, micrometeorite ablation products or a part of the K/T impact ejecta.

  13. Breaking the glass ceiling.

    Science.gov (United States)

    Lazarus, A

    1997-03-01

    The glass ceiling is a form of organizational bias and discrimination that prevents qualified professionals from achieving positions of top governance and leadership. This article examines glass ceiling barriers that keep physicians from the upper reaches of management. While these factors apply mainly to women and minority physicians in academia, and are attributable to sexual harassment and discrimination, physicians as a class are frequently denied executive management positions. Such denial results from inadequate preparation for a career in health care administration. Important issues in the professional development of physician executives include mentoring, training and education, administrative experience, and cultural and personality factors. All of those must be considered when making the transition from medicine to management.

  14. Glasses for Mali

    CERN Multimedia

    PH Department

    2008-01-01

    We are collecting old pairs of glasses to take out to Mali, where they can be re-used by people there. The price for a pair of glasses can often exceed 3 months salary, so they are prohibitively expensive for many people. If you have any old spectacles you can donate, please put them in the special box in the ATLAS secretariat, Bldg.40-4-D01 before the Christmas closure on 19 December so we can take them with us when we leave for Africa at the end of the month. (more details in ATLAS e-news edition of 29 September 2008: http://atlas-service-enews.web.cern.ch/atlas-service-enews/news/news_mali.php) many thanks! Katharine Leney co-driver of the ATLAS car on the Charity Run to Mali

  15. New approach on volatile contents determination in silicate melt inclusions: A coupling X-ray microtomography and geochemical approach in Los Humeros caldera complex (Eastern Mexican Volcanic Belt)

    Science.gov (United States)

    Creon, L.; Levresse, G.; Carrasco Nuñez, G.

    2016-12-01

    Volatile contents and magma degassing behavior are known to affect the style, frequency, and intensity of near-surface magmatic processes. For this reason, much effort have been devoted to characterize the volatile evolution of shallow magmatic systems to better constrain volcanic history. Silicate melt inclusions (SMI) represent samples of melt that were isolated from the bulk magma at depth, thus preserving the PTX conditions of the pre-eruptive material. SMI are often affected by the formation of a bubble after trapping; this is a natural consequence of the PVTX properties of crystal-melt-volatile systems. Previous workers have recognized that bubble formation is an obstacle, which affects the interpretation of SMI trapping conditions based only on analysis of the glass phase. Indeed, they explained that bubbles can contain a significant percentage of the volatiles, particularly for those with low solubility in the melt (e.g. CO2). In this study, we propose to define the pre-eruptive PTX conditions of Los Humeros magma chamber using SMI from the various eruption events within 460 and 30 Ka. An innovative analytical coupling has been used in order to determine: (1) the volume of the SMI glass and bubble, using high resolution 3D X-ray microtomography; (2) the density and composition of the bubbles, using Raman spectroscopy; (3) the volatile element contents in glass, using NanoSIMS; and, (4) the major elements composition of the glass, using EPMA. The recalculated volatile concentrations of the total SMI (glass + bubble), illustrate clearly that the volatile content determinations using only the glass phase, underestimate drastically the total volatile content and therefore induce significant error on the determination of the pre-eruptive volcanic budget and on the constrain on the volcanic and thermal history. This study had moreover highlighted the complex evolution of Los Humeros composite magma chamber and, gave constrains for geothermal exploration purpose.

  16. Payenia volcanic province, southern Mendoza, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin; Llambias, Eduardo Jorge

    2013-01-01

    The Pleistocene to Holocene Payenia volcanic province is a backarc region of 60,000 km2 in Mendoza, Argentina, which is dominated by transitional to alkaline basalts and trachybasalts. We present major and trace element compositions of 139 rocks from this area of which the majority are basaltic...

  17. Monogenetic volcanism: personal views and discussion

    Science.gov (United States)

    Németh, K.; Kereszturi, G.

    2015-11-01

    Monogenetic volcanism produces small-volume volcanoes with a wide range of eruptive styles, lithological features and geomorphic architectures. They are classified as spatter cones, scoria (or cinder) cones, tuff rings, maars (maar-diatremes) and tuff cones based on the magma/water ratio, dominant eruption styles and their typical surface morphotypes. The common interplay between internal, such as the physical-chemical characteristics of magma, and external parameters, such as groundwater flow, substrate characteristics or topography, plays an important role in creating small-volume volcanoes with diverse architectures, which can give the impression of complexity and of similarities to large-volume polygenetic volcanoes. In spite of this volcanic facies complexity, we defend the term "monogenetic volcano" and highlight the term's value, especially to express volcano morphotypes. This study defines a monogenetic volcano, a volcanic edifice with a small cumulative volume (typically ≤1 km3) that has been built up by one continuous, or many discontinuous, small eruptions fed from one or multiple magma batches. This definition provides a reasonable explanation of the recently recognized chemical diversities of this type of volcanism.

  18. Is volcanic phenomena of fractal nature?

    Science.gov (United States)

    Quevedo, R.; Lopez, D. A. L.; Alparone, S.; Hernandez Perez, P. A.; Sagiya, T.; Barrancos, J.; Rodriguez-Santana, A. A.; Ramos, A.; Calvari, S.; Perez, N. M.

    2016-12-01

    A particular resonance waveform pattern has been detected beneath different physical volcano manifestations from recent 2011-2012 period of volcanic unrest at El Hierro Island, Canary Islands, and also from other worldwide volcanoes with different volcanic typology. This mentioned pattern appears to be a fractal time dependent waveform repeated in different time scales (periods of time). This time dependent feature suggests this resonance as a new approach to volcano phenomena for predicting such interesting matters as earthquakes, gas emission, deformation etc. as this fractal signal has been discovered hidden in a wide typical volcanic parameters measurements. It is known that the resonance phenomenon occurring in nature usually denote a structure, symmetry or a subjacent law (Fermi et al., 1952; and later -about enhanced cross-sections symmetry in protons collisions), which, in this particular case, may be indicative of some physical interactions showing a sequence not completely chaotic but cyclic provided with symmetries. The resonance and fractal model mentioned allowed the authors to make predictions in cycles from a few weeks to months. In this work an equation for this waveform has been described and also correlations with volcanic parameters and fractal behavior demonstration have been performed, including also some suggestive possible explanations of this signal origin.

  19. Monitoring and forecasting Etna volcanic plumes

    Directory of Open Access Journals (Sweden)

    S. Scollo

    2009-09-01

    Full Text Available In this paper we describe the results of a project ongoing at the Istituto Nazionale di Geofisica e Vulcanologia (INGV. The objective is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present by multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite, visual and thermal cameras, and three radar disdrometers able to detect ash dispersal and fallout. Forecasting is performed by using automatic procedures for: i downloading weather forecast data from meteorological mesoscale models; ii running models of tephra dispersal, iii plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv publishing the results on a web-site dedicated to the Italian Civil Protection. Simulations are based on eruptive scenarios obtained by analysing field data collected after the end of recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring system. The system was tested on some explosive events occurred during 2006 and 2007 successfully. The potentiality use of monitoring and forecasting Etna volcanic plumes, in a way to prevent threats to aviation from volcanic ash, is finally discussed.

  20. Supersymmetric Spin Glass

    CERN Document Server

    Gukov, S G

    1997-01-01

    The evidently supersymmetric four-dimensional Wess-Zumino model with quenched disorder is considered at the one-loop level. The infrared fixed points of a beta-function form the moduli space $M = RP^2$ where two types of phases were found: with and without replica symmetry. While the former phase possesses only a trivial fixed point, this point become unstable in the latter phase which may be interpreted as a spin glass phase.

  1. Impact of Volcanic Activity on AMC Channel Operations

    Science.gov (United States)

    2014-06-13

    IMPACT OF VOLCANIC ACTIVITY ON AMC CHANNEL OPERATIONS GRADUATE RESEARCH PROJECT Matthew D... VOLCANIC ACTIVITY ON AMC CHANNEL OPERATIONS GRADUATE RESEARCH PROJECT Presented to the Faculty Department of Operational Sciences...AFIT-ENS-GRP-14-J-11 IMPACT OF VOLCANIC ACTIVITY ON AMC CHANNEL OPERATIONS Matthew D. Meshanko, BS, MA Major, USAF

  2. Implications of volcanic erratics in Quaternary deposits of North Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby; Larsen, Ole

    1982-01-01

    Erratic boulders, petrographically similar to the volcanics exposed around Kap Washington, are found on islands and along the coast much further to the east. Isotopic measurements on two such boulders show that these volcanic rocks are of the same age as the Kap Washington volcanics. The regional...

  3. Halogen Chemistry in Volcanic Plumes (Invited)

    Science.gov (United States)

    Roberts, Tjarda

    2017-04-01

    Volcanoes release vast amounts of gases and particles in the atmosphere. Volcanic halogens (HF, HCl, HBr, HI) are co-emitted alongside SO2, and observations show rapid formation of BrO and OClO in the plume as it disperses into the troposphere. The development of 1D and Box models (e.g. PlumeChem) that simulate volcanic plume halogen chemistry aims to characterise how volcanic reactive halogens form and quantify their atmospheric impacts. Following recent advances, these models can broadly reproduce the observed downwind BrO/SO2 ratios using "bromine-explosion" chemistry schemes, provided they use a "high-temperature initialisation" to inject radicals (OH, Cl, Br and possibly NOx) which "kick-start" the low-temperature chemistry cycles that convert HBr into reactive bromine (initially as Br2). The modelled rise in BrO/SO2 and subsequent plateau/decline as the plume disperses downwind reflects cycling between reactive bromine, particularly Br-BrO, and BrO-HOBr-BrONO2. BrCl is produced when aerosol becomes HBr-depleted. Recent model simulations suggest this mechanism for reactive chlorine formation can broadly account for OClO/SO2 reported at Mt Etna. Predicted impacts of volcanic reactive halogen chemistry include the formation of HNO3 from NOx and depletion of ozone. This concurs with HNO3 widely reported in volcanic plumes (although the source of NOx remains under question), as well as observations of ozone depletion reported in plumes from several volcanoes (Mt Redoubt, Mt Etna, Eyjafjallajokull). The plume chemistry can transform mercury into more easily deposited and potentially toxic forms, for which observations are limited. Recent incorporation of volcanic halogen chemistry in a 3D regional model of degassing from Ambrym (Vanuatu) also predicts how halogen chemistry causes depletion of OH to lengthen the SO2 lifetime, and highlights the potential for halogen transport from the troposphere to the stratosphere. However, the model parameter-space is vast and

  4. Development of large-scale production of Nd-doped phosphate glasses for megajoule-scale laser systems

    Science.gov (United States)

    Ficini, Gaelle; Campbell, Jack H.

    1996-08-01

    Nd-doped phosphate glasses are the preferred gain medium for high-peak-power lasers used for inertial confinement fusion research because they have excellent energy storage and extraction characteristics. In addition, these glasses can be manufactured defect-free in large sizes and a t relatively low cost. To meet the requirements of the future megajoule size lasers, advanced laser glass manufacturing methods are being developed that would enable laser glass to be continuously produced at the rate of several thousand large plates of glass per year. This represents more than a 10 to 100-fold improvement in the scale of the present manufacturing technology.

  5. D/H and Water Concentrations of Submarine MORB Glass Around the World: Analytical Aspects, Standardization, and (re)defining Mantle D/H Ranges

    Science.gov (United States)

    Bindeman, I. N.; Dixon, J. E.; Langmuir, C. H.; Palandri, J. L.

    2015-12-01

    The advent and calibration of the Thermal Combustion Element Analyzer (TCEA) continuous flow system coupled with the large-radius mass spectrometer MAT253 permits precise (±0.02 wt.% H2O, ±1-3‰ D/H) measurements in 1-10 mg of volcanic glass (0.1 wt.% H2O requires ~10 mg glass), which permits the targeting of small amounts of the freshest concentrate. This is a >100 factor reduction in sample size over conventional methods, four times over more common Delta series instruments. We investigated in triplicate 115 samples of submarine MORB glasses ranging from water-poor (0.1-0.2wt%) to water-rich (1.2-1.5wt%). These samples were previously investigated for major and trace elements, radiogenic isotopes; a large subset of these samples coming from the FAZAR expedition were studied previously by FTIR for water concentration. We also ran samples previously studied by the conventional off-line technique: MORB glass including those from the Easter Platform and the Alvin 526-1 standard (0.2wt% H2O). We observe excellent 1:1 correspondence (1.02x+0.02, R2=0.94) of wt% water by FTIR and TCEA suggesting complete extraction of water and no dependence on water concentration. We measure 51‰ total range in D/H that correlates with all other chemical and isotopic indicators of mantle enrichment, with the heaviest values occurring in the most enriched samples. When used uncorrected values of H2 gas run against H2 gas of known composition, this range agrees nicely with previous D/H range for MORB (-30 to -90‰), measured for samples run conventionally. Uncorrected analyses of Alvin glass 526-1 gives -66‰. When run against SMOW, SLAP and -41‰ water sealed in silver cups, the range is shifted by -15‰; when standardization is done by with three commonly used mica standards as is done most commonly in different labs, the range is shifted downward by -30-32‰. There are no isotopic offsets related to total water or D/H range requiring different slope or non-linear correction

  6. Structure and petrology of newly discovered volcanic centers in the northern Kermadec-southern Tofua arc, South Pacific Ocean

    Science.gov (United States)

    Graham, Ian J.; Reyes, Agnes G.; Wright, Ian C.; Peckett, Kimberley M.; Smith, Ian E. M.; Arculus, Richard J.

    2008-08-01

    The NZAPLUME III expedition of September-October 2004 to the northern Kermadec-southern Tofua (NKST) arc, between 28°52'S and 25°07'S, resulted in the discovery of at least seven new submarine volcanic centers and a substantial caldera complex adjacent to the previously known Monowai Seamount. The volcanic centers form a sublinear chain that coincides with the Kermadec Ridge crest in the south (Hinetapeka) and diverges ˜45 km westward of the ridge crest in the north ("V") just to the south of where the Louisville Ridge intersects with the arc. All of the centers contain calderas or caldera-like structures, as well as multiple cones, domes, fissure ridges, and vent fields. All show signs of recent eruptive and current hydrothermal activity. There are strong structural controls on edifice location, with cones and fissure ridges typically associated with faulting parallel to the regional ˜12° strike of the arc front. Several of the calderas are ellipsoidal, orientated northwest-southeast in the general direction of least compressive stress. Sampled volcanic rocks, representing the most recently erupted lavas, are all low-K tholeiites. Two of the centers, Gamble and Rakahore, yielded only high-silica dacite to rhyolite (69-74 wt% silica), whereas two others, Monowai and "V," yielded only basalt to andesite (48-63 wt% silica). Mineral assemblages are plagioclase-pyroxene dominated, with accessory Fe-Ti oxides, apatite, olivine, and quartz/tridymite/cristobalite, typical of dry volcanic arc systems. Hornblende occurs only in a felsitic rhyolite from Hinepuia volcanic center, and zircon is absent. Glass contents range to 57% in basalts-andesites (mean 20%), and 97% in andesites-rhyolites (mean 59%) and other quench textures, including swallow-tailed, plumose, or dendritic crystal forms and crystallites, are common. Most lavas are highly vesicular (≤63%; mean 28%) and have low volatile contents (mostly cristobalite, indicates explosive eruption and rapid cooling

  7. Holocene explosive volcanism of the Jan Mayen (island) volcanic province, North-Atlantic

    Science.gov (United States)

    Gjerløw, Eirik; Haflidason, H.; Pedersen, R. B.

    2016-07-01

    The volcanic island Jan Mayen, located in the Norwegian-Greenland Sea, hosts the active stratovolcano of Beerenberg, the northernmost active subaerial volcano in the world. At least five eruptions are known from the island following its discovery in the 17th century, but its eruptive history prior to this is basically unknown. In this paper two sediment cores retrieved close to Jan Mayen have been studied in detail to shed light on the Holocene history of explosive volcanism from the Jan Mayen volcanic province. Horizons with elevated tephra concentrations were identified and tephra from these was analysed to determine major element chemistry of the tephra. The tephra chemistry was used to provide a link between the two cores and the land based tephra records from Jan Mayen Island. We managed to link two well-developed tephra peaks in the cores by their geochemical composition and age to Jan Mayen. One of these peaks represents the 1732 AD eruption of Eggøya while the other peak represents a previously undescribed eruption dated to around 10.3 ka BP. Two less prominent tephra peaks, one in each core, dated to approximately 2.3 and 3.0 ka BP, also have a distinct geochemical character linking them to Jan Mayen volcanism. However, the most prominent tephra layer in the cores located close to Jan Mayen and numerous other cores along the Jan Mayen ridge is the 12.1 ka BP Vedde Ash originating from the Iceland volcanic province. We find that the Holocene volcanism on Jan Mayen is much less explosive than volcanism in Iceland, and propose that either low amounts of explosive volcanic activity from the summit region of Beerenberg or small to absent glacier cover on Beerenberg is responsible for this.

  8. Volcanic lake systematics II. Chemical constraints

    Science.gov (United States)

    Varekamp, J.C.; Pasternack, G.B.; Rowe, G.L.

    2000-01-01

    A database of 373 lake water analyses from the published literature was compiled and used to explore the geochemical systematics of volcanic lakes. Binary correlations and principal component analysis indicate strong internal coherence among most chemical parameters. Compositional variations are influenced by the flux of magmatic volatiles and/or deep hydrothermal fluids. The chemistry of the fluid entering a lake may be dominated by a high-temperature volcanic gas component or by a lower-temperature fluid that has interacted extensively with volcanic rocks. Precipitation of minerals like gypsum and silica can strongly affect the concentrations of Ca and Si in some lakes. A much less concentrated geothermal input fluid provides the mineralized components of some more dilute lakes. Temporal variations in dilution and evaporation rates ultimately control absolute concentrations of dissolved constituents, but not conservative element ratios. Most volcanic lake waters, and presumably their deep hydrothermal fluid inputs, classify as immature acid fluids that have not equilibrated with common secondary silicates such as clays or zeolites. Many such fluids may have equilibrated with secondary minerals earlier in their history but were re-acidified by mixing with fresh volcanic fluids. We use the concept of 'degree of neutralization' as a new parameter to characterize these acid fluids. This leads to a classification of gas-dominated versus rock-dominated lake waters. A further classification is based on a cluster analysis and a hydrothermal speedometer concept which uses the degree of silica equilibration of a fluid during cooling and dilution to evaluate the rate of fluid equilibration in volcano-hydrothermal systems.

  9. Constraints for recently discovered ignimbrites in the Altiplano-Puna Volcanic Complex (APVC), northern Chile

    Science.gov (United States)

    Layana, S.; Aguilera, F.

    2014-12-01

    One of most voluminous ignimbrite provinces in the world (>30.000 km3) is located in the Central Andean Volcanic Zone (CAVZ), which has been continuously active since Upper Oligocene. Altiplano-Puna Volcanic Complex (APVC), located between 21 and 24ºS, is a volcano-tectonic province constituted by diverse caldera complexes and ignimbrite deposits (Upper Miocene - Lower Pleistocene) that covers an area ~50.000 km2. In this work, we present data from three new ignimbrites discovered in a portion of APVC (22°-22,4°S), with the objective to establish its origin and provenance. Were identified 3 new ignimbrites: 1) Cabana ignimbrite (>7.5 Ma), constituted by 3 pyroclastic flow and 1 pyroclastic surge units of crystal-glass rich dacitic tuffs, 80 m maximum thick, 0.18 km3 volume and 0.14 km3 DRE; 2) Inacaliri ignimbrite (7.5 Ma) constituted by two members, corresponding to glassy dacitic (basal member) and basaltic andesites (upper member) tuffs, the total thick reach up 20 m, 0.003 km3 volume and 0.002 km3 DRE; 3) Tolar ignimbrite (>1.3 Ma), constituted by a single pyroclastic flow and a basal fall glassy dacitic deposits, 50 m maximum thick, 0.04 km3 volume and 0.03 km3 DRE. Cabana ignimbrite seems to have been originated from a single caldera complex, whose cannot be recognized in the field. Inacaliri ignimbrite could be related to initial phases of building of Inacaliri and Apacheta-Aguilucho volcanic complexes, or originated to a buried caldera located below both volcanic complexes. Finally, Tolar ignimbrite corresponds to initial building stage of Toconce volcano, located 2 km at NE from these deposits.

  10. Transferability of glass lens molding

    Science.gov (United States)

    Katsuki, Masahide

    2006-02-01

    Sphere lenses have been used for long time. But it is well known that sphere lenses theoretically have spherical aberration, coma and so on. And, aspheric lenses attract attention recently. Plastic lenses are molded easily with injection machines, and are relatively low cost. They are suitable for mass production. On the other hand, glass lenses have several excellent features such as high refractive index, heat resistance and so on. Many aspheric glass lenses came to be used for the latest digital camera and mobile phone camera module. It is very difficult to produce aspheric glass lenses by conventional process of curve generating and polishing. For the solution of this problem, Glass Molding Machine was developed and is spreading through the market. High precision mold is necessary to mold glass lenses with Glass Molding Machine. The mold core is ground or turned by high precision NC aspheric generator. To obtain higher transferability of the mold core, the function of the molding machine and the conditions of molding are very important. But because of high molding temperature, there are factors of thermal expansion and contraction of the mold and glass material. And it is hard to avoid the factors. In this session, I introduce following items. [1] Technology of glass molding and the machine is introduced. [2] The transferability of glass molding is analyzed with some data of glass lenses molded. [3] Compensation of molding shape error is discussed with examples.

  11. Bioactive glass in tissue engineering

    Science.gov (United States)

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  12. Analytical Plan for Roman Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, Denis M.; Buck, Edgar C.; Mueller, Karl T.; Schwantes, Jon M.; Olszta, Matthew J.; Thevuthasan, Suntharampillai; Heeren, Ronald M.

    2011-01-01

    Roman glasses that have been in the sea or underground for about 1800 years can serve as the independent “experiment” that is needed for validation of codes and models that are used in performance assessment. Two sets of Roman-era glasses have been obtained for this purpose. One set comes from the sunken vessel the Iulia Felix; the second from recently excavated glasses from a Roman villa in Aquileia, Italy. The specimens contain glass artifacts and attached sediment or soil. In the case of the Iulia Felix glasses quite a lot of analytical work has been completed at the University of Padova, but from an archaeological perspective. The glasses from Aquileia have not been so carefully analyzed, but they are similar to other Roman glasses. Both glass and sediment or soil need to be analyzed and are the subject of this analytical plan. The glasses need to be analyzed with the goal of validating the model used to describe glass dissolution. The sediment and soil need to be analyzed to determine the profile of elements released from the glass. This latter need represents a significant analytical challenge because of the trace quantities that need to be analyzed. Both pieces of information will yield important information useful in the validation of the glass dissolution model and the chemical transport code(s) used to determine the migration of elements once released from the glass. In this plan, we outline the analytical techniques that should be useful in obtaining the needed information and suggest a useful starting point for this analytical effort.

  13. The Online GVP/USGS Weekly Volcanic Activity Report: Providing Timely Information About Worldwide Volcanism

    Science.gov (United States)

    Mayberry, G. C.; Guffanti, M. C.; Luhr, J. F.; Venzke, E. A.; Wunderman, R. L.

    2001-12-01

    The awesome power and intricate inner workings of volcanoes have made them a popular subject with scientists and the general public alike. About 1500 known volcanoes have been active on Earth during the Holocene, approximately 50 of which erupt per year. With so much activity occurring around the world, often in remote locations, it can be difficult to find up-to-date information about current volcanism from a reliable source. To satisfy the desire for timely volcano-related information the Smithsonian Institution and US Geological Survey combined their strengths to create the Weekly Volcanic Activity Report. The Smithsonian's Global Volcanism Program (GVP) has developed a network of correspondents while reporting worldwide volcanism for over 30 years in their monthly Bulletin of the Global Volcanism Network. The US Geological Survey's Volcano Hazards Program studies and monitors volcanoes in the United States and responds (upon invitation) to selected volcanic crises in other countries. The Weekly Volcanic Activity Report is one of the most popular sites on both organization's websites. The core of the Weekly Volcanic Activity Report is the brief summaries of current volcanic activity around the world. In addition to discussing various types of volcanism, the summaries also describe precursory activity (e.g. volcanic seismicity, deformation, and gas emissions), secondary activity (e.g. debris flows, mass wasting, and rockfalls), volcanic ash hazards to aviation, and preventative measures. The summaries are supplemented by links to definitions of technical terms found in the USGS photoglossary of volcano terms, links to information sources, and background information about reported volcanoes. The site also includes maps that highlight the location of reported volcanoes, an archive of weekly reports sorted by volcano and date, and links to commonly used acronyms. Since the Weekly Volcanic Activity Report's inception in November 2000, activity has been reported at

  14. Zeolitic volcanic tuffs from Macicas (Cluj County, natural raw materials used for NH4+ removal from wastewaters

    Directory of Open Access Journals (Sweden)

    Horea Bedelean

    2006-04-01

    Full Text Available Volcanic tuffs out cropping in Măcicaş area (Cluj County have been investigated and tested for their ammonium removal capacity. The zeolitic volcanic tuffs from Măcicaş are mainly represented by vitric and vitric crystal tuffs. In this region, significant amounts of volcanic glass in the pyroclastic sequence have been replaced by zeolites (between 50-80 %. The main zeolite species identified in volcanic tuffs from Măcicaş is clinoptilolite and subordinately mordenite. The zeolitic tuff samples considered in zeolitic sodium form (labeled M1-Na and M2-Na are tested in ammonium removal experiments. The ammonium ions were completely removed from 0.0716g/dm3 NH4+ solution onto 10g of zeolitic material in static regime. In dynamic regime, the ammonium ions were completely removed after 250 ml and 500 ml solution passed on M1-Na and M2-Na sample respectively. Also the zeolite exhaustion takes place after more than 1500 ml solution is processed in both cases. The ionic exchange properties suggest that the zeolitic tuff of the Măcicaş region can be used as a final stage (following the biological process in wastewater treatment plants in order to assure compliance with environmental standards.

  15. The Mixed-Alkali Effect on The Resistance of Glass to Water

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the composition of float glass, the resistance of glass to water, in which a small amount of K2O (0—1.0 wt%) was substituted for equivalent amount of Na2O, was investigated by means of glass grains testing. The components extracted from the glass and total alkalinities in extraction solution were determined by atomic absorption spectroscopy and neutralizing method, respectively. The composition of the glass was 14.4 K2O+Na2O, 4.0MgO, 8.2CaO, 1.4Al2O3, 72.0 SiO2, and the minimum extraction ratio of oxides (maximum durability) occurred at a K2O/Na2O ratio of 0.051(by weight) due to the presence of the mixed-alkali effect. The relative extraction ratio of alkali oxides (R2O) was greater than that of alkaline earth oxides (RO). By means of mixed-alkali effect and lowing relative contents of R2O in the glass, the resistance of float glass to water was improved and its mildew-proof ability was therefore increased.

  16. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATION

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2015-07-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. In this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  17. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATIONmplification

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2012-06-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. in this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  18. Using Spatial Density to Characterize Volcanic Fields on Mars

    Science.gov (United States)

    Richardson, J. A.; Bleacher, J. E.; Connor, C. B.; Connor, L. J.

    2012-01-01

    We introduce a new tool to planetary geology for quantifying the spatial arrangement of vent fields and volcanic provinces using non parametric kernel density estimation. Unlike parametricmethods where spatial density, and thus the spatial arrangement of volcanic vents, is simplified to fit a standard statistical distribution, non parametric methods offer more objective and data driven techniques to characterize volcanic vent fields. This method is applied to Syria Planum volcanic vent catalog data as well as catalog data for a vent field south of Pavonis Mons. The spatial densities are compared to terrestrial volcanic fields.

  19. Submarine Volcanic Morphology of Santorini Caldera, Greece

    Science.gov (United States)

    Nomikou, P.; Croff Bell, K.; Carey, S.; Bejelou, K.; Parks, M.; Antoniou, V.

    2012-04-01

    Santorini volcanic group form the central part of the modern Aegean volcanic arc, developed within the Hellenic arc and trench system, because of the ongoing subduction of the African plate beneath the European margin throughout Cenozoic. It comprises three distinct volcanic structures occurring along a NE-SW direction: Christianna form the southwestern part of the group, Santorini occupies the middle part and Koloumbo volcanic rift zone extends towards the northeastern part. The geology of the Santorini volcano has been described by a large number of researchers with petrological as well as geochronological data. The offshore area of the Santorini volcanic field has only recently been investigated with emphasis mainly inside the Santorini caldera and the submarine volcano of Kolumbo. In September 2011, cruise NA-014 on the E/V Nautilus carried out new surveys on the submarine volcanism of the study area, investigating the seafloor morphology with high-definition video imaging. Submarine hydrothermal vents were found on the seafloor of the northern basin of the Santorini caldera with no evidence of high temperature fluid discharges or massive sulphide formations, but only low temperature seeps characterized by meter-high mounds of bacteria-rich sediment. This vent field is located in line with the normal fault system of the Kolumbo rift, and also near the margin of a shallow intrusion that occurs within the sediments of the North Basin. Push cores have been collected and they will provide insights for their geochemical characteristics and their relationship to the active vents of the Kolumbo underwater volcano. Similar vent mounds occur in the South Basin, at shallow depths around the islets of Nea and Palaia Kameni. ROV exploration at the northern slopes of Nea Kameni revealed a fascinating underwater landscape of lava flows, lava spines and fractured lava blocks that have been formed as a result of 1707-1711 and 1925-1928 AD eruptions. A hummocky topography at

  20. Insight of the fusion behavior of volcanic ash: Implications for Volcanic ash Hazards to Aircraft Safety

    Science.gov (United States)

    Song, Wenjia; Hess, Kai-Uwe; Küppers, Ulrich; Scheu, Bettina; Cimarelli, Corrado; Lavallée, Yan; Sohyun, Park; Gattermann, Ulf; Müller, Dirk; Dingwell, Donald Bruce

    2014-05-01

    The interaction of volcanic ash with jet turbines during via ingestion of ash into engines operating at supra-volcanic temperatures is widely recognized as a potentially fatal hazard for jet aircraft. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The fusibility of volcanic ash is believed to impact strongly its deposition in the hotter parts of jet engines. Despite this, explicit investigation of ash sintering using standardized techniques is in its infancy. Volcanic ash may vary widely in its physical state and chemical composition between and even within explosive volcanic eruptions. Thus a comparative study of the fusibility of ash which involves a standard recognized techniques would be highly desirable. In this work, nine samples of fine ash, deposited from co-pyroclastic offrom nine different volcanoes which cover a broad range of chemical composition, were investigated. Eight of them were collected from 2001-2009 eruptions. Because of the currently elevated level of eruptive activity and its potential hazards to aircraft safety and the remaining one sample was collected from a 12,121 ± 114 yr B.P. eruption. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the fusion phenomena as well as determine the volcanic ash melting behavior by defining four characteristic temperatures (shrinkage temperature, deformation temperature, hemispherical temperature, and flow temperature) by means of heating microscope instrument and different thermal analysis methods. Here, we find that there are similar sticking ability and flow behavior of

  1. Low Thermal Expansion Glass Ceramics

    CERN Document Server

    Bach, Hans

    2005-01-01

    This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated. This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus g...

  2. Who will buy smart glasses?

    DEFF Research Database (Denmark)

    Rauschnabel, Philipp; Brem, Alexander; Ivens, Bjørn S.

    2015-01-01

    Recent market studies reveal that augmented reality (AR) devices, such as smart glasses, will substantially influence the media landscape. Yet, little is known about the intended adoption of smart glasses, particularly: Who are the early adopters of such wearables? We contribute to the growing body...... of research that investigates the role of personality in predicting media usage by analyzing smart glasses, particularly Google Glass. First, we integrate AR devices into the current evolution of media and technologies. Then, we draw on the Big Five Model of human personality and present the results from two...... studies that investigate the direct and moderating effects of human personality on the awareness and innovation adoption of smart glasses. Our results show that open and emotionally stable consumers tend to be more aware of Google Glass. Consumers who perceive the potential for high functional benefits...

  3. Physical chemistry of glass fracture

    Energy Technology Data Exchange (ETDEWEB)

    Michalske, T.A. [Sandia National Laboratories, Albuquerque, NM (United States)

    1993-12-31

    Since silica glass is a brittle material, its susceptibility to fracture often limits its use in technological applications. Previous studies have demonstrated that the fracture resistance of silica glass is decreased greatly by the presence of chemically reactive species such as water. By studying the effect of controlled amounts of reactive gases on the fracture rate in silica glass, the authors have developed chemical kinetics based models to describe the molecular level processes that lead to stress corrosion fracture of glass. A key aspect of our chemical kinetics based model is the measurement of the stress dependence for the hydrolysis of siloxane bonds. The authors derive the stress dependence for hydrolysis from reaction rate studies that are conducted on strained cyclosiloxane model compounds. The chemical kinetic parameter derived from model compounds is used to successfully predict the fracture behavior of bulk silica glass and the mechanical fatigue of high-strength silica glass fibers in various reactive chemical environments.

  4. Electrical charging of ash in Icelandic volcanic plumes

    CERN Document Server

    Aplin, Karen L; Nicoll, Keri A

    2014-01-01

    The existence of volcanic lightning and alteration of the atmospheric potential gradient in the vicinity of near-vent volcanic plumes provides strong evidence for the charging of volcanic ash. More subtle electrical effects are also visible in balloon soundings of distal volcanic plumes. Near the vent, some proposed charging mechanisms are fractoemission, triboelectrification, and the so-called "dirty thunderstorm" mechanism, which is where ash and convective clouds interact electrically to enhance charging. Distant from the vent, a self-charging mechanism, probably triboelectrification, has been suggested to explain the sustained low levels of charge observed on a distal plume. Recent research by Houghton et al. (2013) linked the self-charging of volcanic ash to the properties of the particle size distribution, observing that a highly polydisperse ash distribution would charge more effectively than a monodisperse one. Natural radioactivity in some volcanic ash could also contribute to self-charging of volcan...

  5. Advances in Glass Ionomer Cements

    OpenAIRE

    KAYA, Dt. Tuğba; TİRALİ, Yard. Doç. Dr. Resmiye Ebru

    2013-01-01

    In recent years there have been a number of innovations and developments with respect to glass ionomer cements and their applications in clinical dentistry. This article considers some of the recent outstanding studies regarding the field of glass ionomer cement applications, adhesion and setting mechanisms, types, advantage and disadvantages among themselves and also to enhance the physical and antibacterial properties under the title of 'Advances in Glass Ionomer Cements'. As their biologic...

  6. Structural color from colloidal glasses

    Science.gov (United States)

    Magkiriadou, Sofia

    When a material has inhomogeneities at a lengthscale comparable to the wavelength of light, interference can give rise to structural colors: colors that originate from the interaction of the material's microstructure with light and do not require absorbing dyes. In this thesis we study a class of these materials, called photonic glasses, where the inhomogeneities form a dense and random arrangement. Photonic glasses have angle-independent structural colors that look like those of conventional dyes. However, when this work started, there was only a handful of colors accessible with photonic glasses, mostly hues of blue. We use various types of colloidal particles to make photonic glasses, and we study, both theoretically and experimentally, how the optical properties of these glasses relate to their structure and constituent particles. Based on our observations from glasses of conventional particles, we construct a theoretical model that explains the scarcity of yellow, orange, and red photonic glasses. Guided by this model, we develop novel colloidal systems that allow a higher degree of control over structural color. We assemble glasses of soft, core-shell particles with scattering cores and transparent shells, where the resonant wavelength can be tuned independently of the reflectivity. We then encapsulate glasses of these core-shell particles into emulsion droplets of tunable size; in this system, we observe, for the first time, angle-independent structural colors that cover the entire visible spectrum. To enhance color saturation, we begin experimenting with inverse glasses, where the refractive index of the particles is lower than the refractive index of the medium, with promising results. Finally, based on our theoretical model for scattering from colloidal glasses, we begin an exploration of the color gamut that could be achieved with this technique, and we find that photonic glasses are a promising approach to a new type of long-lasting, non-toxic, and

  7. Microsheet Glass In Solar Concentrators

    Science.gov (United States)

    Richter, Scott W.

    1993-01-01

    Microsheet glass used as highly protective covering material for developmental concentrating reflectors for solar power systems. Together with other materials, possible to fabricate lightweight, highly reflective, accurate, and long-lived concentrators. Desirable properties include durability and smoothness. Glass not affected by ultraviolet radiation, and not degraded by atomic oxygen, found in low orbits around Earth. Though concentrators intended for use in outer space, noteworthy that terrestrial concentrator fabricated with glass sheet 0.7 mm thick.

  8. Fractionation and Mobility of Thallium in Volcanic Ashes after Eruption of Eyjafjallajökull (2010) in Iceland.

    Science.gov (United States)

    Karbowska, Bozena; Zembrzuski, Wlodzimierz

    2016-07-01

    Volcanic ash contains thallium (Tl), which is highly toxic to the biosphere. The aim of this study was to determine the Tl concentration in fractions of volcanic ash samples originating from the Eyjafjallajökull volcano. A sequential extraction scheme allowed for a study of element migration in the environment. Differential pulse anodic stripping voltammetry using a flow measuring system was selected as the analytical method to determine Tl content. The highest average content of Tl in volcanic ash was determined in the fraction entrapped in the aluminosilicate matrix (0.329 µg g(-1)), followed by the oxidizable fraction (0.173 µg g(-1)). The lowest content of Tl was found in the water soluble fraction (0.001 µg g(-1)); however, this fraction is important due to the fact that Tl redistribution among all the fractions occurs through the aqueous phase.

  9. Toughness of Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Shantanu V. Madge

    2015-07-01

    Full Text Available Bulk metallic glasses (BMGs have desirable properties like high strength and low modulus, but their toughness can show much variation, depending on the kind of test as well as alloy chemistry. This article reviews the type of toughness tests commonly performed and the factors influencing the data obtained. It appears that even the less-tough metallic glasses are tougher than oxide glasses. The current theories describing the links between toughness and material parameters, including elastic constants and alloy chemistry (ordering in the glass, are discussed. Based on the current literature, a few important issues for further work are identified.

  10. Crystallization of copper metaphosphate glass

    Science.gov (United States)

    Bae, Byeong-Soo; Weinberg, Michael C.

    1993-01-01

    The effect of the valence state of copper in copper metaphosphate glass on the crystallization behavior and glass transition temperature has been investigated. The crystallization of copper metaphosphate is initiated from the surface and its main crystalline phase is copper metaphosphate (Cu(PO)3),independent of the (Cu sup 2+)/(Cu(total)). However, the crystal morphology, the relative crystallization rates, and their temperature dependences are affected by the (Cu sup 2+)/(Cu (total)) ratio in the glass. On the other hand, the totally oxidized glass crystallizes from all over the surface. The relative crystallization rate of the reduced glass to the totally oxidized glass is large at low temperature, but small at high temperature. The glass transition temperature of the glass increases as the (Cu sup 2+)/(Cu(total)) ratio is raised. It is also found that the atmosphere used during heat treatment does not influence the crystallization of the reduced glass, except for the formation of a very thin CuO surface layer when heated in air.

  11. The strength of two reinforced glass ionomer materials.

    Science.gov (United States)

    Mazarakis, E; van der Vyver, P J; Janse van Rensburg, S D; de Wet, F A

    1994-08-01

    Preformed stainless steel crowns survive longer than multi-surface amalgams on deciduous molars. With the use of reinforced glass ionomers the bulk of the lost tooth structure can be replaced and the stainless steel crown cemented simultaneously. The purpose of this study was to compare two glass ionomer cements with regard to their shear bond strength (SBS) to the dentine of extracted primary molars and to their diametral tensile strength (DTS). The results showed that Vitremer was significantly (p < 0.01) stronger (DTS:x = 19.21; SBS:x = 7.63) than Ketac-Silver (DTS:x = 8.94; SBS:x = 2.92).

  12. Glass chemistry in volcaniclastic sediments of ODP Leg 107, Site 650, sedimentary sequence: provenance and chronological implications

    Science.gov (United States)

    Calanchi, Natale; Gasparotto, Giorgio; Romagnoli, Claudia

    1994-03-01

    A detailed chemical investigation of volcanic glass fragments from volcaniclastic strata (6 tephras, 1 volcanic debris flow, 12 volcanic turbidites) of ODP Leg 107, Site 650, sedimentary sequence, leads to a varied pattern in terms of both provenance and age constraints. The six analyzed tephra strata indicate a provenance from at least three different volcanic provinces: Aeolian, Campanian, and Sicilian Channel (Pantelleria Island). The older tephra strata (021, 018, 012) have a large amount of "orogenic" rhyodacite/rhyolite deposits that may be attributed to the Aeolian province, although no subaerial coeval volcanic activity of similar composition has so far been documented in the Aeolian Arc. Tephra 007 is related to the Pantelleria Island activity and, particularly, to an ignimbrite episode dated circa 130 ka. Tephra strata 005 and 003, have a clear Campanian provenance, and are correlated with analogous tephra layers, observed in the Tyrrhenian and Ionian seas, dated circa 107 and 60 ka respectively. In the oldest portion of the sequence (from 1.3 to 0.13 Ma), the volcaniclastic sediments were only derived from the Aeolian domain whereas in the latest 130 ka, the Campanian influx becomes much more predominant. Therefore, a general K-enrichment trend is observed in the temporal sequence of all the analyzed samples (almost 700 point analyses) which may be related both to a variation in the source area and to the specific Pleistocene magmatic evolution of the peri-Tyrrhenian volcanic provinces.

  13. Organic light emitting diode with light extracting layer

    Science.gov (United States)

    Lu, Songwei

    2016-06-14

    A light extraction substrate includes a glass substrate having a first surface and a second surface. A light extraction layer is formed on at least one of the surfaces. The light extraction layer is a coating, such as a silicon-containing coating, incorporating nanoparticles.

  14. Helium isotopic variations in volcanic rocks from Loihi Seamount and the Island of Hawaii

    Science.gov (United States)

    Kurz, M.D.; Jenkins, W.J.; Hart, S.R.; Clague, D.

    1983-01-01

    Helium isotopic ratios ranging from 20 to 32 times the atmospheric 3He 4He(RA) have been observed in a suite of 15 basaltic glasses from the Loihi Seamount. These ratios, which are up to four times higher than those of MORB glasses and more than twice those of nearby Kilauea, are strongly suggestive of a primitive source of volatiles supplying this volcanism. The Loihi glasses measured span a broad compositional range, and the 3He/4He ratios were found to be generally lower for the alkali basalts than for the tholeiites. The component with a lower 3He 4He ratio appears to be associated with olivine xenocrysts, within which fluid inclusions are probably the carrier of contaminant helium. One Loihi sample has a much lower isotopic ratio ( 30 RA) helium with some (variable) component of lithospheric contamination added during "breakthrough", while the later stages are characterized by a relaxation toward lithospheric 3He 4He ratios (??? 8 RA) due to isolation of the diapir from the mantle below (as the plate moves on), and subsequent mining of the inherited helium and contamination from the surrounding lithosphere. The abrupt contrast in 3He 4He ratios between Kilauea and Loihi, despite their close proximity, is indicative of the small lateral extent of the plume. ?? 1983.

  15. Characterization of structural relaxation in inorganic glasses using length dilatometry

    Science.gov (United States)

    Koontz, Erick

    characterization technique is comprised of three main components: experimental measurements, fitting of configurational length change, and description of glass behavior by analysis of fitting parameters. N-BK7 optical glass from Schott was used as the proof of concept glass but the main scientific interest was in three chalcogenide glasses: As40Se 60, As20Se80, and Ge17.9As19.7 Se62.4. The dilatometric experiments were carried out using a thermomechanical analyzer (TMA) on glass sample that were synthesized by the author, in all cases except N-BK7. Isothermal structural relaxation measurements were done on (12 mm tall x 3 mm x 3 mm) beams placed vertically in the TMA. The samples were equilibrated at a starting temperature (T 0) until structural equilibrium was reached then a temperature down step was initiated to the final temperature (T 1) and held isothermally until relaxation concluded. The configurational aspect of length relaxation, and therefore volume relaxation was extracted and fit with a Prony series. The Prony series parameters indicated a number of relaxation events occurring within the glass on timescales typically an order of magnitude apart in time. The data analysis showed as many as 4 discrete relaxation times at lower temperatures. The number of discrete relaxation decreased as the temperature increased until just one single relaxation was left in the temperature range just at or above Tg. In the case of N-BK7 these trends were utilized to construct a simple model that could be applied to glass manufacturing in the areas of annealing or PGM. A future development of a rather simple finite element model (FEM) would easily be able to use this model to predict the exponential-like, temperature and time dependent relaxation behaviors of the glass. The predictive model was not extended to the chalcogenide glass studied here, but could easily be applied to them in the future. The relaxation time trends versus temperature showed a definite region of transition between a

  16. Ferro and paramagnetic resonance studies of natural volcanic glasses - Teotihuacan obsidians

    Science.gov (United States)

    Chavez-Rivas, F.; Zamorano-Ulloa, R.; Galland, D.; Regnard, J. R.; Chappert, J.

    1991-11-01

    Teotihuacan black obsidians have been experimentally studied and found to be very heterogeneous magnetically. Isolated high-spin Fe(III) and Mn(II) free ions are readily identified. The well-defined first-derivative Q-band singlet at g = 2.00 is assigned to superparamagnetic centers. A strong grain-size dependence of the overall line shape is observed at X-band. Other properties of the spectral lines indicate the presence of superparamagnetic clusters of magnetite and a range order in these obsidians larger than the common short-range order of the glassy state.

  17. Indigenous Carbon Embedded in Apollo 17 Black Volcanic Glass Surface Deposits

    Science.gov (United States)

    Thomas-Keprta, Kathie L.; Ross, D. K.; Le, L.; Gonzalez, C.; McKay, D. S.; Gibson, E. K.

    2012-01-01

    The assessment of indigenous organic matter in returned lunar samples was one of the primary scientific goals of the Apollo program. The levels of such organic material were expected to be and found to be small. Previous work on this topic includes Murphy et al. [1] who reported the presence of anthropogenic organics with sub-ppm concentrations in Apollo 11 fines. In Apollo 12 samples, Preti et al. [2] detected low levels, < 10 ppb or below, of more complex organic material that may have been synthesized by abrupt heating during analysis. Kvenvolden et al. [3] detected porphyrin-like pigments at the ng to pg level in an Apollo 11 bulk sample. Hodgson et al. [4] and Ponnamperuma et al. [5] suggested that most if not all porphyrins were synthesized from rocket fuel during module landing. Chang et al. [6] reported indigenous carbon ranging from 5-20 g/g in the form of metal carbides in Apollo 11 fines. Hare et al. [7] reported amino acids at he 50 ng/g level in Apollo 11 samples but suggested the results may be explained as contamination. More recently, Clemett et al. [8] reported simple polycyclic aromatic hydrocarbons at concentrations of < 1ppm in an Apollo 16 soil. Low concentrations of lunar organics may be a consequence not only of its paucity, but also its heterogeneous distribution. If the sample size required for a measurement is large relative to the localization of organics, detection is limited not by ultimate sensitivity but rather by the ability to distinguish an indigenous signature from background contamination [9].

  18. Examination of glass-silicon and glass-glass bonding techniques for microfluidic systems

    Energy Technology Data Exchange (ETDEWEB)

    Raley, N.F.; Davidson, J.C.; Balch, J.W.

    1995-10-23

    We report here on the results of experiments concerning particular bonding processes potentially useful for ultimate miniaturization of microfluidic systems. Direct anodic bonding of continuous thin pyrex glass of 250 {mu}m thickness to silicon substrates gives multiple, large voids in the glass. Etchback of thick glass of 1200 {mu}m thickness bonded to silicon substrates gives thin continuous glass layers of 189 {mu}m thickness without voids over areas of 5 cm {times} 12 cm. Glass was also successfully bonded to glass by thermal bonding at 800{degrees}C over a 5 cm {times} 7 cm area. Anticipated applications include microfabricated DNA sequencing, flow injection analysis, and liquid and gas chromatography microinstruments.

  19. Quaternary volcanism in the Acambay graben, Mexican Volcanic Belt: Re-evaluation for potential volcanic danger in central Mexico

    Science.gov (United States)

    Aguirre-Diaz, G. J.; Pedrazzi, D.; Lacan, P.; Roldan-Quintana, J.; Ortuňo, M.; Zuniga, R. R.; Laurence, A.

    2015-12-01

    The Mexican Volcanic Belt (MVB) is best known for the major active stratovolcanoes, such as Popocatépetl, Citlaltépetl and Colima. The most common stratovolcanoes in this province are modest-size cones with heights of 800 to 1000 m. Examples are Tequila, Sangangüey, Las Navajas, Culiacán, La Joya, El Zamorano, Temascalcingo and Altamirano; these last two were formed within the Acambay Graben in central MVB. The Acambay graben (20 x 70 km) is 100 km to the NW of Mexico City, with E-W trending seismically active normal faults; in particular the Acambay-Tixmadejé fault related to a mB =7 earthquake in 1912. Within the graben there are many volcanic structures, including calderas, domes, cinder cones and stratovolcanoes; Temascalcingo and Altamirano are the largest, with about 800 and 900 m heights, respectively. Temascalcingo is mostly composed of dacitic lavas and block and ash flow deposits. Includes a 3 x 2.5 km summit caldera and a magmatic sector collapse event with the associated debris avalanche deposit. 14C ages of 37-12 ka correspond to the volcano's latest phases that produced pyroclastic deposits. A major plinian eruption formed the San Mateo Pumice with an age of <20 Ka. Altamirano volcano is poorly studied; it is andesitic-dacitic, composed of lavas, pyroclastic flow deposits, and pumice fallouts. Morphologically is better preserved than Temascalcingo, and it should be younger. 14C ages of 4.0-2.5 ka were performed in charcoal within pyroclastic flow deposits that apparently were erupted from Altamirano. An undated 3 m thick pumice fallout on the flanks of Altamirano volcano could be also Holocene. It represents a major explosive event. The relatively young ages found in volcanic deposits within the Acambay graben raise the volcanic danger level in this area, originally thought as an inactive volcanic zone. The two major volcanoes, Temascalcingo and Altamirano, should be considered as dormant volcanoes that could restart activity at any time. We

  20. Noise-induced variability of volcanic extrusions

    Science.gov (United States)

    Alexandrov, D. V.; Bashkirtseva, I. A.; Ryashko, L. B.

    2016-11-01

    Motivated by important physical applications, we study a non-linear dynamics of volcanic extrusions on the basis of a simple pressure-mass flow model. We demonstrate that the deterministic phase portrait represents either the bulbous-type curves or closed paths stretched to their left depending on the initial conditions. The period of phase trajectories therewith increases when the pressure drop between the conduit top and bottom compensates the lava column pressure in it. Stochastic forcing changes the system dynamics drastically. We show that a repetitive scenario of volcanic behaviour with intermittency of stochastic oscillations of different extrusion amplitudes and frequencies appears in the presence of noises. As this takes place, the mean values of interspike intervals characterizing the system periodicity have a tendency to grow with increasing the noise intensity. The probability distribution functions confirming this dynamic behaviour are constructed.

  1. Triggering of volcanic eruptions by large earthquakes

    Science.gov (United States)

    Nishimura, Takeshi

    2017-08-01

    When a large earthquake occurs near an active volcano, there is often concern that volcanic eruptions may be triggered by the earthquake. In this study, recently accumulated, reliable data were analyzed to quantitatively evaluate the probability of the occurrence of new eruptions of volcanoes located near the epicenters of large earthquakes. For volcanoes located within 200 km of large earthquakes of magnitude 7.5 or greater, the eruption occurrence probability increases by approximately 50% for 5 years after the earthquake origin time. However, no significant increase in the occurrence probability of new eruptions was observed at distant volcanoes or for smaller earthquakes. The present results strongly suggest that new eruptions are likely triggered by static stress changes and/or strong ground motions caused by nearby large earthquakes. This is not similar to the previously presented evidence that volcanic earthquakes at distant volcanoes are remotely triggered by surface waves generated by large earthquakes.

  2. Learning to recognize volcanic non-eruptions

    Science.gov (United States)

    Poland, Michael P.

    2010-01-01

    An important goal of volcanology is to answer the questions of when, where, and how a volcano will erupt—in other words, eruption prediction. Generally, eruption predictions are based on insights from monitoring data combined with the history of the volcano. An outstanding example is the A.D. 1980–1986 lava dome growth at Mount St. Helens, Washington (United States). Recognition of a consistent pattern of precursors revealed by geophysical, geological, and geochemical monitoring enabled successful predictions of more than 12 dome-building episodes (Swanson et al., 1983). At volcanic systems that are more complex or poorly understood, probabilistic forecasts can be useful (e.g., Newhall and Hoblitt, 2002; Marzocchi and Woo, 2009). In such cases, the probabilities of different types of volcanic events are quantified, using historical accounts and geological studies of a volcano's past activity, supplemented by information from similar volcanoes elsewhere, combined with contemporary monitoring information.

  3. Volcanic ash impacts on critical infrastructure

    Science.gov (United States)

    Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

    2012-01-01

    Volcanic eruptions can produce a wide range of hazards. Although phenomena such as pyroclastic flows and surges, sector collapses, lahars and ballistic blocks are the most destructive and dangerous, volcanic ash is by far the most widely distributed eruption product. Although ash falls rarely endanger human life directly, threats to public health and disruption to critical infrastructure services, aviation and primary production can lead to significant societal impacts. Even relatively small eruptions can cause widespread disruption, damage and economic loss. Volcanic eruptions are, in general, infrequent and somewhat exotic occurrences, and consequently in many parts of the world, the management of critical infrastructure during volcanic crises can be improved with greater knowledge of the likely impacts. This article presents an overview of volcanic ash impacts on critical infrastructure, other than aviation and fuel supply, illustrated by findings from impact assessment reconnaissance trips carried out to a wide range of locations worldwide by our international research group and local collaborators. ‘Critical infrastructure’ includes those assets, frequently taken for granted, which are essential for the functioning of a society and economy. Electricity networks are very vulnerable to disruption from volcanic ash falls. This is particularly the case when fine ash is erupted because it has a greater tendency to adhere to line and substation insulators, where it can cause flashover (unintended electrical discharge) which can in turn cause widespread and disruptive outages. Weather conditions are a major determinant of flashover risk. Dry ash is not conductive, and heavy rain will wash ash from insulators, but light rain/mist will mobilise readily-soluble salts on the surface of the ash grains and lower the ash layer’s resistivity. Wet ash is also heavier than dry ash, increasing the risk of line breakage or tower/pole collapse. Particular issues for water

  4. The structure of volcanic cristobalite in relation to its toxicity; relevance for the variable crystalline silica hazard

    Directory of Open Access Journals (Sweden)

    Horwell Claire J

    2012-11-01

    Full Text Available Abstract Background Respirable crystalline silica (RCS continues to pose a risk to human health worldwide. Its variable toxicity depends on inherent characteristics and external factors which influence surface chemistry. Significant population exposure to RCS occurs during volcanic eruptions, where ashfall may cover hundreds of square km and exposure may last years. Occupational exposure also occurs through mining of volcanic deposits. The primary source of RCS from volcanoes is through collapse and fragmentation of lava domes within which cristobalite is mass produced. After 30 years of research, it is still not clear if volcanic ash is a chronic respiratory health hazard. Toxicological assays have shown that cristobalite-rich ash is less toxic than expected. We investigate the reasons for this by determining the physicochemical/structural characteristics which may modify the pathogenicity of volcanic RCS. Four theories are considered: 1 the reactivity of particle surfaces is reduced due to co-substitutions of Al and Na for Si in the cristobalite structure; 2 particles consist of aggregates of cristobalite and other phases, restricting the surface area of cristobalite available for reactions in the lung; 3 the cristobalite surface is occluded by an annealed rim; 4 dissolution of other volcanic particles affects the surfaces of RCS in the lung. Methods The composition of volcanic cristobalite crystals was quantified by electron microprobe and differences in composition assessed by Welch’s two sample t-test. Sections of dome-rock and ash particles were imaged by scanning and transmission electron microscopy, and elemental compositions of rims determined by energy dispersive X-ray spectroscopy. Results Volcanic cristobalite contains up to 4 wt. % combined Al2O3 and Na2O. Most cristobalite-bearing ash particles contain adhered materials such as feldspar and glass. No annealed rims were observed. Conclusions The composition of volcanic

  5. Comparison of Leaching Rates of Glass-Ceramic and Glass

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>With the increase of the burn-up of the nuclear fuel, the amounts of the long-lived radionuclides increase. The solubility of actinides such as plutonium in glass is very limited. Glass-ceramic as the new

  6. POROUS WALL, HOLLOW GLASS MICROSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Sexton, W.

    2012-06-30

    Hollow Glass Microspheres (HGM) is not a new technology. All one has to do is go to the internet and Google{trademark} HGM. Anyone can buy HGM and they have a wide variety of uses. HGM are usually between 1 to 100 microns in diameter, although their size can range from 100 nanometers to 5 millimeters in diameter. HGM are used as lightweight filler in composite materials such as syntactic foam and lightweight concrete. In 1968 a patent was issued to W. Beck of the 3M{trademark} Company for 'Glass Bubbles Prepared by Reheating Solid Glass Particles'. In 1983 P. Howell was issued a patent for 'Glass Bubbles of Increased Collapse Strength' and in 1988 H. Marshall was issued a patent for 'Glass Microbubbles'. Now Google{trademark}, Porous Wall, Hollow Glass Microspheres (PW-HGMs), the key words here are Porous Wall. Almost every article has its beginning with the research done at the Savannah River National Laboratory (SRNL). The Savannah River Site (SRS) where SRNL is located has a long and successful history of working with hydrogen and its isotopes for national security, energy, waste management and environmental remediation applications. This includes more than 30 years of experience developing, processing, and implementing special ceramics, including glasses for a variety of Department of Energy (DOE) missions. In the case of glasses, SRS and SRNL have been involved in both the science and engineering of vitreous or glass based systems. As a part of this glass experience and expertise, SRNL has developed a number of niches in the glass arena, one of which is the development of porous glass systems for a variety of applications. These porous glass systems include sol gel glasses, which include both xerogels and aerogels, as well as phase separated glass compositions, that can be subsequently treated to produce another unique type of porosity within the glass forms. The porous glasses can increase the surface area compared to &apos

  7. The Zuni-Bandera Volcanic Field, NM: An Analog for Exploring Planetary Volcanic Terrains

    Science.gov (United States)

    Bleacher, J. E.; Garry, W. B.; Zimbelman, J. R.; Crumpler, L. S.; Aubele, J. C.

    2010-12-01

    The Zuni-Bandera volcanic field, near Grants, New Mexico, is comprised of volcanic deposits from several basaltic eruptions during the last million years. This vent field exhibits a diverse group of coalesced lava flows and displays well-preserved volcanic features including a’a and pahoehoe flows, collapsed lava tubes, cinder cones and low shields. The McCartys flow is a 48-km long inflated basalt flow and is the youngest in the field at around 3000 years old. Over the last three years we have used the Zuni-Bandera volcanic field, and the McCartys flow in particular, as a terrestrial analog for exploring planetary volcanic fields, and understanding the role of lava sheet inflation in flow field development. We have conducted three different styles of analog tests, 1) basic field science focused on understanding lava sheet inflation, 2) mission operations tests related to EVA design and real-time modification of traverse plans, and 3) science enabling technology tests. The Zuni-Bandera field is an ideal location for each style of analog test because it provides easy access to a diverse set of volcanic features with variable quality of preservation. However, many limitations must also be considered in order to maximize lessons learned. The McCartys flow displays well-preserved inflation plateaus that rise up to 15 m above the surrounding field. The preservation state enables textures and morphologies indicative of this process to be characterized. However, the pristine nature of the flow does not compare well with the much older and heavily modified inflated flows of Mars and the Moon. Older flows west of McCartys add value to this aspect of analog work because of their degraded surfaces, development of soil horizons, loose float, and limited exposure of outcrops, similar to what might be observed on the Moon or Mars. EVA design tests and science enabling technology tests at the Zuni-Bandera field provide the opportunity to document and interpret the relationships

  8. Volcanic alert system (VAS) developed during the 2011-2014 El Hierro (Canary Islands) volcanic process

    Science.gov (United States)

    García, Alicia; Berrocoso, Manuel; Marrero, José M.; Fernández-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Ortiz, Ramón

    2014-06-01

    The 2011 volcanic unrest at El Hierro Island illustrated the need for a Volcanic Alert System (VAS) specifically designed for the management of volcanic crises developing after long repose periods. The VAS comprises the monitoring network, the software tools for analysis of the monitoring parameters, the Volcanic Activity Level (VAL) management, and the assessment of hazard. The VAS presented here focuses on phenomena related to moderate eruptions, and on potentially destructive volcano-tectonic earthquakes and landslides. We introduce a set of new data analysis tools, aimed to detect data trend changes, as well as spurious signals related to instrumental failure. When data-trend changes and/or malfunctions are detected, a watchdog is triggered, issuing a watch-out warning (WOW) to the Monitoring Scientific Team (MST). The changes in data patterns are then translated by the MST into a VAL that is easy to use and understand by scientists, technicians, and decision-makers. Although the VAS was designed specifically for the unrest episodes at El Hierro, the methodologies may prove useful at other volcanic systems.

  9. Minerogenesis of volcanic caves of Kenya.

    Directory of Open Access Journals (Sweden)

    Rossi Antonio

    2003-01-01

    Full Text Available Kenya is one of the few countries in which karst cavities are scarce with respect to volcanic ones, which are widespread throughout the whole country. The great variability in lava composition allowed the evolution of very different cavities, some of which are amongst the largest lava tubes of the world. As normal for such a kind of cave, the hosted speleothems and cave minerals are scarce but important from the minerogenetic point of view. Anyway up to present no specific mineralogical research have been carried out therein. During the 8th International Symposium on Volcanospeleology, held in Nairobi in February 1998, some of the most important volcanic caves of Kenya have been visited and their speleothems and/or chemical deposits sampled: most of them were related to thick guano deposits once present inside these cavities. Speleothems mainly consisted of opal or gypsum, while the deposits related to guano often resulted in a mixture of sulphates and phosphates. The analyses confirmed the great variability in the minerogenetic mechanisms active inside the volcanic caves, which consequently allow the evolution of several different minerals even if the total amount of chemical deposit is scarce. Among the observed minerals kogarkoite, phillipsite and hydroxyapophyllite, must be cited because they are new cave minerals not only for the lava tubes of Kenya, but also for the world cave environment. The achieved results are compared with the available random data from previous literature in order to allow an updated overview on the secondary cave minerals of Kenya.

  10. Amazonian volcanism inside Valles Marineris on Mars

    Science.gov (United States)

    Brož, Petr; Hauber, Ernst; Wray, James J.; Michael, Gregory

    2017-09-01

    The giant trough system of Valles Marineris is one of the most spectacular landforms on Mars, yet its origin is still unclear. Although often referred to as a rift, it also shows some characteristics that are indicative of collapse processes. For decades, one of the major open questions was whether volcanism was active inside the Valles Marineris. Here we present evidence for a volcanic field on the floor of the deepest trough of Valles Marineris, Coprates Chasma. More than 130 individual edifices resemble scoria and tuff cones, and are associated with units that are interpreted as lava flows. Crater counts indicate that the volcanic field was emplaced sometime between ∼0.4 Ga and ∼0.2 Ga. The spatial distribution of the cones displays a control by trough-parallel subsurface structures, suggesting magma ascent in feeder dikes along trough-bounding normal faults. Spectral data reveal an opaline-silica-rich unit associated with at least one of the cones, indicative of hydrothermal processes. Our results point to magma-water interaction, an environment of astrobiological interest, perhaps associated with late-stage activity in the evolution of Valles Marineris, and suggest that the floor of Coprates Chasma is promising target for the in situ exploration of Mars.

  11. Venus volcanism: initial analysis from magellan data.

    Science.gov (United States)

    Head, J W; Campbell, D B; Elachi, C; Guest, J E; McKenzie, D P; Saunders, R S; Schaber, G G; Schubert, G

    1991-04-12

    Magellan images confirm that volcanism is widespread and has been fimdamentally important in the formation and evolution of the crust of Venus. High-resolution imaging data reveal evidence for intrusion (dike formation and cryptodomes) and extrusion (a wide range of lava flows). Also observed are thousands of small shield volcanoes, larger edifices up to several hundred kilometers in diameter, massive outpourings of lavas, and local pyroclastic deposits. Although most features are consistent with basaltic compositions, a number of large pancake-like domes are morphologically similar to rhyolite-dacite domes on Earth. Flows and sinuous channels with lengths of many hundreds of kilometers suggest that extremely high effusion rates or very fluid magmas (perhaps komatiites) may be present. Volcanism is evident in various tectonic settings (coronae, linear extensional and compressional zones, mountain belts, upland rises, highland plateaus, and tesserae). Volcanic resurfacing rates appear to be low (less than 2 Km(3)/yr) but the significance of dike formation and intrusions, and the mode of crustal formation and loss remain to be established.

  12. Venus volcanism: Initial analysis from Magellan data

    Science.gov (United States)

    Head, J.W.; Campbell, D.B.; Elachi, C.; Guest, J.E.; Mckenzie, D.P.; Saunders, R.S.; Schaber, G.G.; Schubert, G.

    1991-01-01

    Magellan images confirm that volcanism is widespread and has been fundamentally important in the formation and evolution of the crust of Venus. High-resolution imaging data reveal evidence for intrusion (dike formation and cryptodomes) and extrusion (a wide range of lava flows). Also observed are thousands of small shield volcanoes, larger edifices up to several hundred kilometers in diameter, massive outpourings of lavas, and local pyroclastic deposits. Although most features are consistent with basaltic compositions, a number of large pancake-like domes are morphologically similar to rhyolite-dacite domes on Earth. Flows and sinuous channels with lengths of many hundreds of kilometers suggest that extremely high effusion rates or very fluid magmas (perhaps komatiites) may be present. Volcanism is evident in various tectonic settings (coronae, linear extensional and compressional zones, mountain belts, upland rises, highland plateaus, and tesserae). Volcanic resurfacing rates appear to be low (less than 2 km3/yr) but the significance of dike formation and intrusions, and the mode of crustal formation and loss remain to be established.

  13. Halogens behaviours in Magma Degassing: Insights into Eruptive Dynamics, Hydrothermal Systems and Atmospheric Impact of Andesitic Volcanism

    Science.gov (United States)

    Villemant, B.; Balcone, H.; Mouatt, J.; Michel, A.; Komorowski, J.; Boudon, G.

    2007-12-01

    Shallow degassing of H2O in andesitic magmas determines the eruptive styles of volcanic eruptions and contributes to the hydrothermal systems developed around active volcanoes. Halogens behaviour during magma degassing primarily depends on their incompatible behaviour in the melts and on water solubility. Thus, residual contents of halogens in volcanic juvenile vitric clasts may be used as tracers of H2O degassing processes during explosive and effusive eruptions. Because of the large range of water-melt partition coefficients of halogens and their relatively low diffusion coefficients, a comparison of F, Cl, Br and I contents in volcanic clasts in function of their vesicularity and micro-cristallinity allows to precisely model the main degassing processes and to establish constraints on pre-eruptive conditions. Halogens acids (HCl, HBr and HI) extracted in the vapour phase have much more complex behaviours because of their high solubility in low temperature thermal waters, their variable condensation temperatures and their very high reactivity when mixed with low temperature and oxidizing atmospheric gases. A comparison of model compositions of high temperature gases with the composition of thermal waters, and gases from fumaroles or plumes of active volcanoes allows to characterise the shallow volcanic system and its evolutionary states. Variable halogen behaviours are discussed for a variety of eruption types (plinian, vulcanian and dome-forming) and active volcanic systems from the Lesser Antilles (Montagne Pelee, Soufrière of Guadeloupe, Soufriere Hills of Montserrat).

  14. INORGANIC PHOSPHORS IN GLASS BASED ON LEAD SILICATE GLASSES

    Directory of Open Access Journals (Sweden)

    V. A. Aseev

    2014-09-01

    Full Text Available We created and synthesized luminescent composite of the "phosphor in glass" type, based on the lead-silicate matrix and fine-dispersed powder of cerium-activated yttrium-aluminum garnet crystal. Lead-silicate system (40SiO2- 20PbO-(40-x PbF2-xAlF3, x = 0-25 was chosen as the glassy matrix. Initial glass was reduced to powder (frit for "phosphor in glass" composite with a particle size about 50 µm. Glass frit and powder of commercial YAG:Ce3+ phosphor were mixed in a ratio of 30 to 70 (wt %. Then this composite was pressed in a tablet and sintered on a quartz substrate at 823 К for 30 minutes. Thus, the plane parallel sheet for composite of the "phosphor in glass" was obtained with a diameter equal to 10 mm. For the purpose to reduce the loss of light in the presence of dispersion at a glass-phosphor boundary, optimization of glass mixture was done by adjusting the refractive index. X-ray phase and spectral-luminescent analysis of the derived composite were done. The results of these studies showed that there was no degradation of YAG: Ce powder during sintering. Dependence of luminescence intensity from temperature in the range from room temperature to 473 К was studied. It was shown, that with the phosphor in glass usage thermal quenching of luminescence was reduced in comparison with the silicone. The model of white LED was created with the "phosphor in glass" composite based on lead-silicate glasses with low temperature of vitrifying. The derived LED emits white light with a color temperature of 4370 K, and the luminous efficiency is equal to 58 lm/W. The developed luminescent composite based on the lead-silicate matrix can be used for the production of high-power white light LED.

  15. Crustal and tectonic controls on large-explosive volcanic eruptions

    Science.gov (United States)

    Sheldrake, Tom; Caricchi, Luca

    2017-04-01

    Quantifying the frequency-Magnitude (f-M) relationship for volcanic eruptions is important to estimate volcanic hazard. Furthermore, understanding how this relationship varies between different groups of volcanoes can provide insights into the processes that control the size and rate of volcanic events. Using a Bayesian framework, which allows us to conceptualise the volcanic record as a series of individual and unique time series, associated by a common group behaviour, we identify variations in the size and rate of volcanism in different volcanic arcs. These variations in behaviour are linked to key parameters that include the motion of subduction, rate of subduction, age of the slab and thickness of the crust. The effects of these parameters on volcanism are interpreted in terms of variations in mantle productivity and the thermal efficiency of magma transfer in arc crustal systems. Understanding the link between subduction architecture, heat content of magmatic systems, and volcanic activity will serve to improve our capacity to quantify volcanic hazard in regions with limited geological and historical records of volcanic activity.

  16. Neogene volcanism in Gutai Mts. (Eastern Carpathains: a review

    Directory of Open Access Journals (Sweden)

    Marinel Kovacs

    2003-04-01

    Full Text Available Two types of volcanism developed in Gutâi Mts. (inner volcanic chain of Eastern Carpathians: a felsic, extensional/“back-arc” type and an intermediate, arc type. The felsic volcanism of explosive origin, consisting of caldera-related rhyolitic ignimbrites and resedimented volcaniclastics, had taken place during Early-Middle Badenian and Early Sarmatian. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The geochemical study on the volcanic rocks shows the calc-alkaline character of both felsic and intermediate volcanism and typical subduction zones geochemical signatures for the intermediate one. The felsic volcanism shows affinities with subduction-related rocks as well. The main petrogenetic process in Gutâi Mts. was crustal assimilation, strongly constrained by trace element and isotope geochemistry.

  17. Global volcanic emissions: budgets, plume chemistry and impacts

    Science.gov (United States)

    Mather, T. A.

    2012-12-01

    Over the past few decades our understanding of global volcanic degassing budgets, plume chemistry and the impacts of volcanic emissions on our atmosphere and environment has been revolutionized. Global volcanic emissions budgets are needed if we are to make effective use of regional and global atmospheric models in order to understand the consequences of volcanic degassing on global environmental evolution. Traditionally volcanic SO2 budgets have been the best constrained but recent efforts have seen improvements in the quantification of the budgets of other environmentally important chemical species such as CO2, the halogens (including Br and I) and trace metals (including measurements relevant to trace metal atmospheric lifetimes and bioavailability). Recent measurements of reactive trace gas species in volcanic plumes have offered intriguing hints at the chemistry occurring in the hot environment at volcanic vents and during electrical discharges in ash-rich volcanic plumes. These reactive trace species have important consequences for gas plume chemistry and impacts, for example, in terms of the global fixed nitrogen budget, volcanically induced ozone destruction and particle fluxes to the atmosphere. Volcanically initiated atmospheric chemistry was likely to have been particularly important before biological (and latterly anthropogenic) processes started to dominate many geochemical cycles, with important consequences in terms of the evolution of the nitrogen cycle and the role of particles in modulating the Earth's climate. There are still many challenges and open questions to be addressed in this fascinating area of science.

  18. Late Holocene volcanism at Medicine Lake Volcano, northern California Cascades

    Science.gov (United States)

    Donnelly-Nolan, Julie M.; Champion, Duane E.; Grove, Timothy L.

    2016-05-23

    Late Holocene volcanism at Medicine Lake volcano in the southern Cascades arc exhibited widespread and compositionally diverse magmatism ranging from basalt to rhyolite. Nine well-characterized eruptions have taken place at this very large rear-arc volcano since 5,200 years ago, an eruptive frequency greater than nearly all other Cascade volcanoes. The lavas are widely distributed, scattered over an area of ~300 km2 across the >2,000-km2 volcano. The eruptions are radiocarbon dated and the ages are also constrained by paleomagnetic data that provide strong evidence that the volcanic activity occurred in three distinct episodes at ~1 ka, ~3 ka, and ~5 ka. The ~1-ka final episode produced a variety of compositions including west- and north-flank mafic flows interspersed in time with fissure rhyolites erupted tangential to the volcano’s central caldera, including the youngest and most spectacular lava flow at the volcano, the ~950-yr-old compositionally zoned Glass Mountain flow. At ~3 ka, a north-flank basalt eruption was followed by an andesite eruption 27 km farther south that contains quenched basalt inclusions. The ~5-ka episode produced two caldera-focused dacitic eruptions. Quenched magmatic inclusions record evidence of intrusions that did not independently reach the surface. The inclusions are present in five andesitic, dacitic, and rhyolitic host lavas, and were erupted in each of the three episodes. Compositional and mineralogic evidence from mafic lavas and inclusions indicate that both tholeiitic (dry) and calcalkaline (wet) parental magmas were present. Petrologic evidence records the operation of complex, multi-stage processes including fractional crystallization, crustal assimilation, and magma mixing. Experimental evidence suggests that magmas were stored at 3 to 6 km depth prior to eruption, and that both wet and dry parental magmas were involved in generating the more silicic magmas. The broad distribution of eruptive events and the relative

  19. Glasses in the D'Orbigny Angrite

    Science.gov (United States)

    Varela, M. E.; Kurat, G.; Brandstätter, F.; Bonnin-Mosbah, M.; Metrich, N.

    2001-03-01

    The D'Orbigny angrite contains abundant glasses, a phase which has not been previously reported from any other angrite. Glasses fill in part open druses and intersticial spaces between major silicates, or occur as glass inclusions in olivine.

  20. Fullerene-doped porous glasses

    Science.gov (United States)

    Joshi, M. P.; Kukreja, L. M.; Rustagi, K. C.

    We report the doping of C60 in porous glass by diffusion in solution phase at room temperature. The presence of C60 in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials.

  1. Fullerene-doped porous glasses

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, M.P. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group; Kukreja, L.M. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group; Rustagi, K.C. [Center for Adv. Technol., Indore (India). Nonlinear Optics Group

    1997-07-01

    We report the doping of C{sub 60} in porous glass by diffusion in solution phase at room temperature. The presence of C{sub 60} in the doped porous glass was confirmed spectroscopically. We also report the changes in optical absorption spectrum and intensity-dependent transmission of 30 ns laser pulses at 527 nm in these materials. (orig.)

  2. International Congress on Glass XII

    Energy Technology Data Exchange (ETDEWEB)

    Doremus, R H; LaCourse, W C; Mackenzie, J D; Varner, J R; Wolf, W W [eds.

    1980-01-01

    A total of 158 papers are included under nine headings: structure and glass formation; optical properties; electrical and magnetic properties; mechanical properties and relaxation; mass transport; chemical durability and surfaces; nucleation; crystallization; and glass ceramics; processing; and automatic controls. Separate abstracts were prepared for eight papers; four of the remaining papers had been processed previously for the data base. (DLC)

  3. Molecular mobility in sugar glasses

    NARCIS (Netherlands)

    Dries, van den I.J.

    2000-01-01

    Glasses are liquids that exhibit solid state behavior as a result of their extremely high viscosity. Regarding their application to foods, glasses play a role in the preservation of foods, due to their high viscosity and the concomitant low molecular mobility. This thesis focuses on sugar g

  4. Holder for rotating glass body

    Science.gov (United States)

    Kolleck, Floyd W.

    1978-04-04

    A device is provided for holding and centering a rotating glass body such as a rod or tube. The device includes a tubular tip holder which may be held in a lathe chuck. The device can utilize a variety of centering tips each adapted for a particular configuration, such as a glass O-ring joint or semi-ball joint.

  5. OPAL Various Lead Glass Blocks

    CERN Multimedia

    These lead glass blocks were part of a CERN detector called OPAL (one of the four experiments at the LEP particle detector). OPAL uses some 12 000 blocks of glass like this to measure particle energies in the electromagnetic calorimeter. This detector measured the energy deposited when electrons and photons were slowed down and stopped.

  6. High level triggers for explosive mafic volcanism: Albano Maar, Italy

    Science.gov (United States)

    Cross, J. K.; Tomlinson, E. L.; Giordano, G.; Smith, V. C.; De Benedetti, A. A.; Roberge, J.; Manning, C. J.; Wulf, S.; Menzies, M. A.

    2014-03-01

    Colli Albani is a quiescent caldera complex located within the Roman Magmatic Province (RMP), Italy. The recent Via dei Laghi phreatomagmatic eruptions led to the formation of nested maars. Albano Maar is the largest and has erupted seven times between ca 69-33 ka. The highly explosive nature of the Albano Maar eruptions is at odds with the predominant relatively mafic (SiO2 = 48-52 wt.%) foiditic (K2O = 9 wt.%) composition of the magma. The deposits have been previously interpreted as phreatomagmatic, however they contain large amounts (up to 30%vol) of deep seated xenoliths, skarns and all pre-volcanic subsurface units. All of the xenoliths have been excavated from depths of up to 6 km, rather than being limited to the depth at which magma and water interaction is likely to have occurred, suggesting an alternative trigger for eruption. High precision geochemical glass and mineral data of fresh juvenile (magmatic) clasts from the small volume explosive deposits indicate that the magmas have evolved along one of two evolutionary paths towards foidite or phonolite. The foiditic melts record ca. 50% mixing between the most primitive magma and Ca-rich melt, late stage prior to eruption. A major result of our study is finding that the generation of Ca-rich melts via assimilation of limestone, may provide storage for significant amounts of CO2 that can be released during a mixing event with silicate magma. Differences in melt evolution are inferred as having been controlled by variations in storage conditions: residence time and magma volume.

  7. Eruptive dynamics and hazards associated with obsidian bearing ignimbrites of the Geghama Volcanic Highland, Central Armenia: a textural insight

    Science.gov (United States)

    Matthews, Zoe; Manning, Christina J.

    2017-04-01

    insight into the eruptive dynamics and emplacement history [5]. In particular, microlite number density, volume and alignment represent the summation of degassing, conduit flow and emplacement [6]. As such, there is great significance in the quantification of these parameters for the determination of eruption dynamics. Analysis of these obsidians will establish patterns of textural heterogeneity as a signature for the distinction of volcanic glasses formed by different mechanisms and allow for identification of patterns in microlite number density, volume, alignment and plunge that characterise differing modes of emplacement. Together, these measurements will aid interpretation and improve understanding of this volcanic system, with applicability to the determination of the impact of these volcanic episodes on the distribution of early man in Armenia as well as assessment of the potential for future events. [1] Lebedev et al (2013) JVS, 7, 204-229 [2] Arutyunyan et al (2007) Dokl Earth Sci, 416, 1042-1046 [3] Alder et al (2014) Science, 345, 1609-1613 [4] Hutchison et al (2016) Nat. Commun, 7 [5] Manga (1998) JVGR, 86, 107-115 [6] Befus et al (2015) Bull. Volcanol, 77, 88

  8. Specific heat anomaly in relaxor ferroelectrics and dipolar glasses

    Science.gov (United States)

    Kutnjak, Z.; Pirc, R.

    2017-03-01

    The temperature and electric field dependence of the specific heat of relaxor ferroelectrics and dipolar glasses is investigated by means of a Landau-type theoretical model. It is shown that the dipolar specific heat, which is due to the randomly interacting polar nanoregions in relaxors and electric dipoles in dipolar glasses, is negative in a temperature region below the permittivity maximum. Also, it follows that for sufficiently low values of the field, where the induced polarization shows a quasi linear field dependence, the dipolar specific heat is proportional to the second temperature derivative of the dielectric polarization. This quantity can be extracted from the experimental temperature profile of the polarization, thus enabling an indirect experimental estimate of the negative specific heat, which is demonstrated for a set of representative relaxor and dipolar glass systems.

  9. Basaltic ignimbrites in monogenetic volcanism: the example of La Garrotxa volcanic field

    Science.gov (United States)

    Martí, J.; Planagumà, L. l.; Geyer, A.; Aguirre-Díaz, G.; Pedrazzi, D.; Bolós, X.

    2017-05-01

    Ignimbrites are pyroclastic density current deposits common in explosive volcanism involving intermediate and silicic magmas and in less abundance in eruptions of basaltic central and shield volcanoes. However, they are not widely described in association with monogenetic volcanism, where typical products include lava flows, scoria and lapilli fall deposits, as well as various kinds of pyroclastic density current deposits and explosion breccias. In La Garrotxa basaltic monogenetic volcanic field, part of the Neogene-Quaternary European rift system located in the northeast of the Iberian Peninsula, we have identified a particular group of pyroclastic density current deposits that show similar textural characteristics to silicic ignimbrites, indicating an overlap in transport and depositional processes. These deposits can be clearly distinguished from other pyroclastic density current deposits generated during phreatomagmatic phases that typically correspond to thinly laminated units with planar-to-cross-bedded stratification. The monogenetic ignimbrite deposits correspond to a few meters to several tens of meters thick units rich in lithic- and lapilli scoria fragments, with an abundant ash matrix, and internally massive structure, emplaced along valleys and gullies, with run-out distances up to 6 km and individual volumes ranging from 106 to 1.5 × 107 m3. The presence of flattened scoria and columnar jointing in some of these deposits suggests relatively high emplacement temperatures, coinciding with available paleomagnetic data that suggests an emplacement temperature around 450-500 °C. In this work, we describe the main characteristics of these pyroclastic deposits that were generated by a number of phreatomagmatic episodes. Comparison with similar deposits from silicic eruptions and previous examples of ignimbrites associated with basaltic volcanism allows us to classify them as `basaltic ignimbrites'. The recognition in monogenetic volcanism of such

  10. Cluster Analysis of vents in monogenetic volcanic fields, Lunar Crater Volcanic Field (Nevada)

    Science.gov (United States)

    Tadini, A.; Cortes, J. A.; Valentine, G. A.; Johnson, P. J.; Tibaldi, A.; Bonali, F. L.

    2012-12-01

    Monogenetic volcanic fields pose a serious risk to human activities and settlements due to their high occurrence around the world and because of the type of eruptive activity that they exhibit. The need of adequate tools to better undertake volcanic hazard assessment for volcanic fields, especially from a spatial point of view, is of key importance at the time of mitigate such hazard. Among these tools, a better understanding of the spatial distribution of cones and vents and any structural/tectonical relationship are essential to understand the plumbing system of the field and thus help to predict the likelihood location of future eruptions. In this study we have developed a spatial methodology, which is the combination of various methodologies developed for volcanic textures and other clustering goals [1,2], to study the clustering of volcanic vents and their relation with structural features from satellite images. The methodology first involves the statistical identification and removal of spatial outliers using a predictive elliptical area [2] and the generation of randomly distributed points in the same predictive area. A comparison of the Near Neighbor Distance (NND) between the generated data and the data measured in a volcanic field is used to determine whether the vents are clustered or not. If the vents are clustered, a combination of hierarchical clustering and K-means [3] is then used to identify the clusters and their related vents. Results are then further constrained with the study of lineaments and other structural features that can be affected and related with the clusters. The methodology was tested in the Lunar Crater Volcanic Field, Nevada (USA) and successfully has helped to identify tectonically controlled lineaments from those that are resultant of geomorphological processes such the drainage control imposed by the cone clusters. Theoretical approaches has been developed before to constrain the plumbing of a volcanic field [4], however these

  11. Database and Interim Glass Property Models for Hanford HLW Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R; Piepel, Gregory F; Vienna, John D; Cooley, Scott K; Kim, Dong-Sang; Russell, Renee L

    2001-07-24

    The purpose of this report is to provide a methodology for an increase in the efficiency and a decrease in the cost of vitrifying high-level waste (HLW) by optimizing HLW glass formulation. This methodology consists in collecting and generating a database of glass properties that determine HLW glass processability and acceptability and relating these properties to glass composition. The report explains how the property-composition models are developed, fitted to data, used for glass formulation optimization, and continuously updated in response to changes in HLW composition estimates and changes in glass processing technology. Further, the report reviews the glass property-composition literature data and presents their preliminary critical evaluation and screening. Finally the report provides interim property-composition models for melt viscosity, for liquidus temperature (with spinel and zircon primary crystalline phases), and for the product consistency test normalized releases of B, Na, and Li. Models were fitted to a subset of the screened database deemed most relevant for the current HLW composition region.

  12. GRID based Thermal Images Processing for volcanic activity monitoring

    Science.gov (United States)

    Mangiagli, S.; Coco, S.; Drago, L.; Laudani, A.,; Lodato, L.; Pollicino, G.; Torrisi, O.

    2009-04-01

    Since 2001, the Catania Section of the National Institute of Geophysics and Volcanology (INGV) has been running the video stations recording the volcanic activity of Mount Etna, Stromboli and the Fossa Crater of Vulcano island. The video signals of 11 video cameras (seven operating in the visible band and four in infrared) are sent in real time to INGV Control Centre where they are visualized on monitors and archived on a dedicated NAS storage. The video surveillance of the Sicilian volcanoes, situated near to densely populated areas, helps the volcanologists providing the Civil Protection authorities with updates in real time on the on-going volcanic activity. In particular, five video cameras are operating on Mt. Etna and they record the volcano from the south and east sides 24 hours a day. During emergencies, mobile video stations may also be used to better film the most important phases of the activity. Single shots are published on the Catania Section intranet and internet websites. On June 2006 a A 40 thermal camera was installed in Vulcano La Fossa Crater. The location was in the internal and opposite crater flank (S1), 400 m distant from the fumarole field. The first two-year of data on temperature distribution frequency were recorded with this new methodology of acquisition, and automatically elaborated by software at INGV Catania Section. In fact a dedicated software developed in IDL, denominated Volcano Thermo Analysis (VTA), was appositely developed in order to extract a set of important features, able to characterize with a good approssimation the volcanic activity. In particular the program first load and opportunely convert the thermal images, then according to the Region Of Interest (ROI) and the temperature ranges defined by the user provide to automatic spatial and statistic analysis. In addition the VTA is able to analysis all the temporal series of images available in order to achieve the time-event analysis and the dynamic of the volcanic

  13. Recovery of palladium, cesium, and selenium from heavy metal alkali borosilicate glass by combination of heat treatment and leaching processes

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhanglian; Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Nishimura, Fumihiro; Yonezawa, Susumu

    2017-06-05

    Highlights: • A separation technique of both noble and less noble metal from glass is studied. • Via reductive heat treatment, 80% of palladium is extracted in liquid bismuth. • Sodium–potassium-rich materials with cesium and selenium are phase separated. • From the materials, over 80% of cesium and selenium are extracted in water. - Abstract: Reductive heat-treatment and leaching process were applied to a simulated lead or bismuth soda-potash-borosilicate glass with palladium, cesium, and selenium to separate these elements. In the reductive heat treatment, palladium is extracted in liquid heavy metal phase generated by the reduction of the heavy metal oxides, whereas cesium and selenium are concentrated in phase separated Na–K-rich materials on the glass surface. From the materials, cesium and selenium can be extracted in water, and the selenium extraction was higher in the treatment of the bismuth containing glass. The chemical forms of palladium in the glass affected the extraction efficiencies of cesium and selenium. Among the examined conditions, in the bismuth glass treatment, the cesium and selenium extraction efficiencies in water were over 80%, and that of palladium in liquid bismuth was over 80%.

  14. Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A.A.

    1995-07-01

    This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading.

  15. The Yucca Mountain probabilistic volcanic hazard analysis project

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, K.J.; Perman, R.C.; Youngs, R.R. [Geomatrix Consultants, Inc., San Francisco, CA (United States)] [and others

    1996-12-01

    The Probabilistic Volcanic Hazard Analysis (PVHA) project, sponsored by the U.S. Department of Energy (DOE), was conducted to assess the probability of a future volcanic event disrupting the potential repository at Yucca Mountain. The PVHA project is one of the first major expert judgment studies that DOE has authorized for technical assessments related to the Yucca Mountain project. The judgments of members of a ten-person expert panel were elicited to ensure that a wide range of approaches were considered for the hazard analysis. The results of the individual elicitations were then combined to develop an integrated assessment of the volcanic hazard that reflects the diversity of alternative scientific interpretations. This assessment, which focused on the volcanic hazard at the site, expressed as the probability of disruption of the potential repository, will provide input to an assessment of volcanic risk, which expresses the probability of radionuclide release due to volcanic disruption.

  16. Assessing volcanic hazard at Yucca Mountain using expert judgment

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, K.J.; Perman, R.C. [Geomatrix Consultants, Inc., San Francisco, CA (United States); Nesbit, J. [Department of Energy, Las Vegas, NV (United States)] [and others

    1995-12-01

    A study to assess the probability of a future volcanic event disrupting the potential repository at Yucca Mountain, termed the Probabilistic Volcanic Hazard Analysis (PVHA) project, is being sponsored by the U.S. Department of Energy (DOE). This assessment, which is focused on the volcanic hazard at the site, expressed as the probability of disruption of the potential repository, will eventually provide input to an assessment of volcanic risk, which expresses the probability of radionuclide release due to volcanic disruption. To ensure that a wide range of approaches are considered in the hazard analysis, judgments of members of an expert panel will be elicited. The results of the individual elicitations will be combined to develop an integrated assessment of the volcanic hazard that reflects the diversity of scientific interpretations. This paper outlines the hazard model components and the procedures for eliciting expert judgments.

  17. Volcanic geology of Admiralty Bay, King George Island, Antarctica

    Institute of Scientific and Technical Information of China (English)

    邢光福; 王德滋; 金庆民; 沈渭洲; 陶奎元

    2002-01-01

    At Admiralty Bay of central King George Island, Keller Peninsula, Ullman Spur and Point Hennequin are main Tertiary volcanic terranes. Field investigation and isotopic datings indicate that, there occurred three periods of eruptions ( three volcanic cycles) and accompanying N-toward migration of the volcanic center on Keller Peninsula. After the second period of eruptions, the crater collapsed and a caldera was formed, then later eruptions were limited at the northern end of the peninsula and finally migrated to Ullman Spur. Thus Keller Peninsula is a revived caldera, and its volcanism migrated toward E with time. Point Hennequin volcanism happened more or less simultaneously with the above two areas, but has no clear relation in chemical evolution with them, frequently it belongs to another independent volcanic center.

  18. Supervolcanoes within an ancient volcanic province in Arabia Terra, Mars.

    Science.gov (United States)

    Michalski, Joseph R; Bleacher, Jacob E

    2013-10-03

    Several irregularly shaped craters located within Arabia Terra, Mars, represent a new type of highland volcanic construct and together constitute a previously unrecognized Martian igneous province. Similar to terrestrial supervolcanoes, these low-relief paterae possess a range of geomorphic features related to structural collapse, effusive volcanism and explosive eruptions. Extruded lavas contributed to the formation of enigmatic highland ridged plains in Arabia Terra. Outgassed sulphur and erupted fine-grained pyroclastics from these calderas probably fed the formation of altered, layered sedimentary rocks and fretted terrain found throughout the equatorial region. The discovery of a new type of volcanic construct in the Arabia volcanic province fundamentally changes the picture of ancient volcanism and climate evolution on Mars. Other eroded topographic basins in the ancient Martian highlands that have been dismissed as degraded impact craters should be reconsidered as possible volcanic constructs formed in an early phase of widespread, disseminated magmatism on Mars.

  19. Genesis and Eruptive Dynamics of the Garnet-Bearing Rhyolites from the Ramadas Volcanic Centre (Altiplano-Puna Plateau, Central Andes, Argentina).

    Science.gov (United States)

    De Astis, G.; Baez, W.; Bardelli, L.; Becchio, R.; Giordano, G.; Lucci, F.; Rossetti, F.; Viramonte, J. G.

    2015-12-01

    Ramadas volcanic centre (6.6 Ma) is a monogenetic calderic depression, now largely obliterated, almost coeval with the Late Miocene outbreak of highly explosive silicic activity in the Altiplano-Puna plateau. Ramadas erupted a rather complex suite of garnet-bearing, rhyolitic pyroclastic rocks, dominated by a >35 km3 fall deposit and preceded by the emplacement of a lag breccia containing abundant metasedimentary lithics and garnet-tourmaline leucogranites. During the waning stage of the eruption, small volume phreatomagmatic deposits formed a small tuff-ring, followed by a lava coulée emplacement. Volcanological data together with textural features of typical tube pumice evidence a volatiles-rich, plinian eruption. Petrographic and textural studies on juveniles confirm the presence of euhedral garnet as dominant phase and identify micrometric metaigneous fragments (Qtz+Bt+Kfs+Mt+Tur). BSE imaging and microprobe analyses on glasses, garnets and accessory mineral phases (zircon and monazite) provide further data to understand the genesis and eruptive conditions of these atypical rhyolites, geochemically different from those outcropping in the same region. Garnets display a homogeneous, unzoned almandine-spessartine composition (Alm72-71Sps24-23Pyr0-1Grs4-3) and are contained in a glassy rhyolitic magma with peraluminous character, HREE depleted and relative LREE enriched. It's known that primary igneous garnets are rare and can only develop under restricted conditions. Additionally, the presence of Zr and Mnz is associated with both magmatic and high-T metamorphic processes. Although more data need to be collected, our study and preliminary modelling point to the occurrence of thermal metamorphism shifting to partial melting of Fe-MnO-rich metapelitic rocks (or even re-melting of older acid volcanics), with final extraction of volatiles-rich rhyolitic melts, able to produce a plinian eruption. Here, Alm-Sps garnet could represent the peritectic product of the

  20. Joints in Tempered Glass Using Glass Dowel Discs

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Poulsen, Peter Noe

    One of the major reasons for using glass in structures is its transparency; however, traditional mechanical joints such as friction joints and steel dowel pinned connections are compromising the transparency. The present paper describes a novel joint which is practically maintaining the complete...... transparency of the glass. This is achieved by using a dowel disc made entirely of tempered glass. The concept of the joint is proved by pilot tests and numerical models. From the work it is seen that the load-carrying capacity of such a connection is similar to what is found for traditionally in-plane loaded...

  1. The α-β phase transition in volcanic cristobalite.

    OpenAIRE

    Damby, D. E.; Llewellin, E.W.; Horwell, C. J.; Williamson, B.J.; Najorka, J; Cressey, G.; Carpenter, M.A.

    2014-01-01

    Cristobalite is a common mineral in volcanic ash produced from dome-forming eruptions. Assessment of the respiratory hazard posed by volcanic ash requires understanding the nature of the cristobalite it contains. Volcanic cristobalite contains coupled substitutions of Al3+ and Na+ for Si4+; similar co-substitutions in synthetic cristobalite are known to modify the crystal structure, affecting the stability of the α and β forms and the observed transition between them. Here, for the first time...

  2. Distinguishing volcanic lithology using Self-Organizing Map

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Self-Organizing Map is an unsupervised learning algorithm. It has the ability of self-organization,self-learning and side associative thinking. Based on the principle it can identified the complex volcanic lithology. According to the logging data of the volcanic rock samples, the SOM will be trained, The SOM training results were analyzed in order to choose optimally parameters of the network. Through identifying the logging data of volcanic formations, the result shows that the map can achieve good application effects.

  3. VOLCANIC TSUNAMI GENERATING SOURCE MECHANISMS IN THE EASTERN CARIBBEAN REGION

    OpenAIRE

    2004-01-01

    Earthquakes, volcanic eruptions, volcanic island flank failures and underwater slides have generated numerous destructive tsunamis in the Caribbean region. Convergent, compressional and collisional tectonic activity caused primarily from the eastward movement of the Caribbean Plate in relation to the North American, Atlantic and South American Plates, is responsible for zones of subduction in the region, the formation of island arcs and the evolution of particular volcanic centers on the over...

  4. Impact glass spherules in the Chicxulub K-Pg event bed at Beloc, Haiti: Alteration patterns

    Science.gov (United States)

    Ritter, Xenia; Deutsch, Alexander; Berndt, Jasper; Robin, Eric

    2015-03-01

    We have investigated six impact glass spherules from the K-Pg event bed at Beloc, Haiti, using optical and electron microscopy, electron microprobe and in situ laser ablation-mass spectrometry (LA-ICP-MS; 37 trace elements, spot size 90-35 μm), in order to understand geochemical changes during alteration. The mm-sized glass spherules are partly or totally altered to smectite, but original textural features are preserved. The average trace-element composition of glass matches that one of the upper continental crust. Hints for a "meteoritic component" are lacking (Ni/Cr < 1.3 Pt below detection limit). Compared to this fresh glass, smectites are strongly depleted in trace elements, except for Li, Sc, V, Ni, Ga, Ge, and Ba. The chondrite-normalized REE distribution patterns are flat with subchondritic abundances, related to their very low degree of crystallinity. We observe a positive Eu and a strong negative Ce anomaly; the latter is explained by formation of an organic Ce4+-complex, soluble under reducing conditions. Zr/Hf of glasses and smectites is chondritic to superchondritic (35-40), whereas Nb/Ta in smectite is subchondritic (5-12) compared to Nb/Ta in the glass (~14-18). The low Nb/Ta is due to the low Nb concentrations in the smectite. Using in situ techniques with high spatial resolution, we have documented for the first time the significant changes in diagnostic elemental ratios during alteration of glass spherules. This has to be taken into account in the interpretation of geochemical data of not only impact materials but also volcanic glass, especially if bulk rock methods are used.

  5. Spectra of the Wells lunar glass simulants: New old data for reflectance modeling

    Science.gov (United States)

    Stockstill-Cahill, Karen R.; Blewett, David T.; Cahill, Joshua T. S.; Denevi, Brett W.; Lawrence, Samuel J.; Coman, Ecaterina I.

    2014-05-01

    Silicate glasses are an important constituent in the regolith of airless planetary bodies, and knowledge of glass reflectance characteristics is important for remote-sensing studies of the Moon, Mercury, and asteroids. We recovered reflectance spectra for 20 vacuum-melted lunar glass simulants measured by Wells (1977), which cover a wider range of Fe and Ti contents (0-17.5 wt % FeO and 0-15 wt % TiO2) and a wider wavelength range than those of the better-known Bell et al. (1976) study. We examine the spectra in terms of known absorptions, explore the relationship between ultraviolet spectral parameters and composition, and apply the Hapke radiative transfer model to predict the reflectance spectra of the Wells glasses. The imaginary part of the refractive index (k) at each wavelength was computed based on the Ti and Fe composition using the linear relationship presented by Wilcox et al. (2006) and with a new linear-exponential hybrid relationship. Comparison of the model spectra with the measured spectra reveals that the samples rich in Fe and Ti are best modeled by the linear relationship, because the linear model was developed using the Fe- and/or Ti-rich Bell et al. (1976) glasses. For Fe- and Ti-poor glasses, the hybrid model provides a better fit to the measured spectra, because this model for k is based on the wider compositional range of the Wells glasses. In the future, better linear model fits might be obtained if optical parameters were derived for a wider compositional range, from low-Fe/low-Ti to the higher-Fe/higher-Ti compositions of Apollo volcanic glasses.

  6. Leachates analysis of glass from black and white and color televisions sets

    Directory of Open Access Journals (Sweden)

    Radovan Kukla

    2012-01-01

    Full Text Available The aim of work was to determine the content of selected elements in the glass from color and black and white television (TV sets. The amount of back taken TV sets in the Czech Republic increases annualy, which is associated with higher production of the waste glass. Currently there is 1.4 television sets for each household and the number of it should increase in future, because of higher standard of living and new technologies used. Waste glass treatment or landfilling may present, because of composition of the waste glass threat to the environment. One of the indicators of the polution from waste glass is leachate analysis, which can show us the content of hazardous substances in the waste glass, which can be released to the environment. A qualitative analysis of leachate samples was carried out by UV-VIS spectrophotometer. The results showed concentration of potencionaly hazardous substances contained in leachate samples. This was especially content of aluminum, cadmium, chromium, copper, molybdenum, nickel, lead, tin and zinc. Results of analyzes of the aqueous extract of glass were confronted with the limits specified in the currently valid legislation. Based on the results there is clear that in the case of landfilling of the glass from television sets, there is possibility of the contamination of landfill leachate by the elements, which are presented in the glass.

  7. Distribution and characteristics of volcanic reservoirs in China

    Institute of Scientific and Technical Information of China (English)

    HUANG Yulong; WANG Pujun; CHEN Shuming

    2009-01-01

    About forty productive oil/gas fields hosted in volcanic reservoirs have been found since 1957 in fourteen basins of China. They can be simply subdivided into two groups, the east and the west. Reservoir volcanic rocks of the east group are predominantly composed of Late Jurassic to Early Cretaceous rhyolite and Tertiary basalt, preferred being considered as rift type volcanics developed in the circum-Pacific tectonic regime. Those of the west are Permo-Carboniferous intermediate/basic volcanic rocks, being island-arc type ones developed in paleo-Asian Ocean tectonic regime.

  8. The volcanic and tectonic history of Enceladus

    Science.gov (United States)

    Kargel, J.S.; Pozio, S.

    1996-01-01

    Enceladus has a protracted history of impact cratering, cryo-volcanism, and extensional, compressional, and probable strike-slip faulting. It is unique in having some of the outer Solar System's least and most heavily cratered surfaces. Enceladus' cratering record, tectonic features, and relief elements have been analyzed more comprehensively than done previously. Like few other icy satellites, Enceladus seems to have experienced major lateral lithospheric motions; it may be the only icy satellite with global features indicating probable lithospheric convergence and folding. Ridged plains, 500 km across, consist of a central labyrinthine ridge complex atop a broad dome surrounded by smooth plains and peripheral sinuous ridge belts. The ridged plains have few if any signs of extension, almost no craters, and an average age of just 107 to 108 years. Ridge belts have local relief ranging from 500 to 2000 m and tend to occur near the bottoms of broad regional troughs between swells. Our reanalysis of Peter Thomas' (Dermott, S. F., and P. C. Thomas, 1994, The determination of the mass and mean density of Enceladus from its observed shape, Icarus, 109, 241-257) limb profiles indicates that high peaks, probably ridge belts, also occur in unmapped areas. Sinuous ridges appear foldlike and are similar to terrestrial fold belts such as the Appalachians. If they are indeed folds, it may require that the ridged plains are mechanically (perhaps volcanically) layered. Regional topography suggests that folding may have occurred along zones of convective downwelling. The cratered plains, in contrast to the ridged plains, are heavily cratered and exhibit extensional structures but no obvious signs of compression. Cratered plains contain a possible strike-slip fault (Isbanir Fossa), along which two pairs of fractures seem to have 15 km of right-lateral offset. The oldest cratered plains might date from shortly after the formation of the saturnian system or the impact disruption and

  9. Exceptional Volumes of Rejuvenated Volcanism in Samoa

    Science.gov (United States)

    Konter, J. G.; Jackson, M.; Storm, L.

    2010-12-01

    The internal structure of within-plate volcanoes is typically compared to the stages of volcanic evolution in Hawaii. In Samoa, these stages show some differences with the Hawaiian model, in terms of the duration, volume and geochemical composition of the stages. Particularly, the rejuvenated stage of volcanism in Samoa is significantly more voluminous, with increasing geographic coverage with age, completely repaving the island of Savai’i. This unusual outpouring of rejuvenated lavas has previously been proposed to be related to the tectonic setting, near the northern terminus of the Tonga Trench. Therefore, Samoan volcanism might be caused by lithospheric fracturing, a mantle plume, or potentially a combination of the two. We collected new samples from a deeply eroded canyon on Savai’i to determine a time evolution of the transition from shield to eventual rejuvenated lavas. The canyon exposes several hundred meters of lavas, and we collected samples about 200m vertically down into the canyon. These samples are dominantly olivine basalts, and their Pb isotope compositions fall within the compositional field of young rejuvenated lavas on Savai’i and Upolu. This canyon section, therefore, represents a minimum thickness for the rejuvenated lavas of 200m. Assuming eruption of rejuvenated lavas only occurred subaerially, with a universal thickness of 200m, the new data suggest more than one percent of the volume of Savai’i consists of rejuvenated lavas. This is an order of magnitude greater than the largest relative volumes in Hawaii (Kauai), and implies a different cause for rejuvenated volcanism in Samoa. Another feature that suggests different processes may be important is the transition between the shield and rejuvenated stage. Although Samoan volcanoes do not seem to erupt exactly the same rock types as characteristic Hawaiian post-shield stage lavas, there is a definite shift to more evolved compositions (including trachytes) during the later stages of

  10. [Respiratory function in glass blowers].

    Science.gov (United States)

    Zuskin, E; Butković, D; Mustajbegović, J

    1992-01-01

    The prevalence of chronic and acute respiratory symptoms and diseases and changes in lung function in a group of 80 glass blowers have been investigated. In addition a group of 80 not exposed workers was used as a control group for respiratory symptoms and diseases. In glass blowers, there was significant increase in prevalence of chronic bronchitis, nasal catarrh, and sinusitis than in the controls. Glass blowers exposed for more and less than 10 years had similar prevalences of respiratory symptoms. A large number of glass blowers complained of acute across-shift symptoms. Significant increase in FVC, FEF50 and FEF25 was documented at the end of the work shift. Comparison with predicted normal values showed that glass blowers had FVC and FEF25 significantly lower than predicted. RV and RV/TLC were significantly increased compared with the predicted normal values. DLCO was within the normal values in most glass blowers. It is concluded that work in the glass blower industry is likely to lead the development of chronic respiratory disorders.

  11. Hierarchical probabilistic regionalization of volcanism for Sengan region in Japan using multivariate statistical techniques and geostatistical interpolation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jinyong [Univ. of Arizona, Tucson, AZ (United States); Balasingham, P [Univ. of Arizona, Tucson, AZ (United States); McKenna, Sean Andrew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kulatilake, Pinnaduwa H.S.W. [Univ. of Arizona, Tucson, AZ (United States)

    2004-09-01

    Sandia National Laboratories, under contract to Nuclear Waste Management Organization of Japan (NUMO), is performing research on regional classification of given sites in Japan with respect to potential volcanic disruption using multivariate statistics and geo-statistical interpolation techniques. This report provides results obtained for hierarchical probabilistic regionalization of volcanism for the Sengan region in Japan by applying multivariate statistical techniques and geostatistical interpolation techniques on the geologic data provided by NUMO. A workshop report produced in September 2003 by Sandia National Laboratories (Arnold et al., 2003) on volcanism lists a set of most important geologic variables as well as some secondary information related to volcanism. Geologic data extracted for the Sengan region in Japan from the data provided by NUMO revealed that data are not available at the same locations for all the important geologic variables. In other words, the geologic variable vectors were found to be incomplete spatially. However, it is necessary to have complete geologic variable vectors to perform multivariate statistical analyses. As a first step towards constructing complete geologic variable vectors, the Universal Transverse Mercator (UTM) zone 54 projected coordinate system and a 1 km square regular grid system were selected. The data available for each geologic variable on a geographic coordinate system were transferred to the aforementioned grid system. Also the recorded data on volcanic activity for Sengan region were produced on the same grid system. Each geologic variable map was compared with the recorded volcanic activity map to determine the geologic variables that are most important for volcanism. In the regionalized classification procedure, this step is known as the variable selection step. The following variables were determined as most important for volcanism: geothermal gradient, groundwater temperature, heat discharge, groundwater

  12. Automatic landslides detection on Stromboli volcanic Island

    Science.gov (United States)

    Silengo, Maria Cristina; Delle Donne, Dario; Ulivieri, Giacomo; Cigolini, Corrado; Ripepe, Maurizio

    2016-04-01

    Landslides occurring in active volcanic islands play a key role in triggering tsunami and other related risks. Therefore, it becomes vital for a correct and prompt risk assessment to monitor landslides activity and to have an automatic system for a robust early-warning. We then developed a system based on a multi-frequency analysis of seismic signals for automatic landslides detection occurring at Stromboli volcano. We used a network of 4 seismic 3 components stations located along the unstable flank of the Sciara del Fuoco. Our method is able to recognize and separate the different sources of seismic signals related to volcanic and tectonic activity (e.g. tremor, explosions, earthquake) from landslides. This is done using a multi-frequency analysis combined with a waveform patter recognition. We applied the method to one year of seismic activity of Stromboli volcano centered during the last 2007 effusive eruption. This eruption was characterized by a pre-eruptive landslide activity reflecting the slow deformation of the volcano edifice. The algorithm is at the moment running off-line but has proved to be robust and efficient in picking automatically landslide. The method provides also real-time statistics on the landslide occurrence, which could be used as a proxy for the volcano deformation during the pre-eruptive phases. This method is very promising since the number of false detections is quite small (landslide increases. The final aim will be to apply this method on-line and for a real-time automatic detection as an improving tool for early warnings of tsunami-genic landslide activity. We suggest that a similar approach could be also applied to other unstable non-volcanic also slopes.

  13. Volcanic hazard assessment at Deception Island

    Science.gov (United States)

    Bartolini, S.; Sobradelo, R.; Geyer, A.; Martí, J.

    2012-04-01

    Deception Island is the most active volcano of the South Shetland Islands (Antarctica) with more than twenty eruptions recognised over the past two centuries. The island was formed on the expansion axis of the Central Bransfield Strait and its evolution consists of constructive and destructive phases. A first a shield phase was followed by the construction of a central edifice and formation of the caldera with a final monogenetic volcanism along the caldera rim. The post-caldera magma composition varies from andesitic-basaltic to dacitic. The activity is characterised by monogenetic eruptions of low volume and short duration. The eruptions show a variable degree of explosivity, strombolian or phreatomagmatic, with a VEI 2 to 4, which have generated a wide variety of pyroclastic deposits and lavas. It is remarkable how many phases of phreatic explosive eruptions are associated to the emission of large ballistic blocks. Tephra record preserved in the glacier ice of Livingston Island or in marine sediments show the explosive power of the phreatomagmatic phases and the wide dispersal of its finest products in a great variety of directions of the prevailing winds. Also it is important to highlight the presence of different lahar deposits associated with some of these eruptions. In this contribution we present the guidelines to conduct a short-term and long-term volcanic hazard assessment at Deception Island. We apply probabilistic methods to estimate the susceptibility, statistical techniques to determine the eruption recurrence and eruptive scenario, and reproduce the effects of historical eruptions too. Volcanic hazard maps and scenarios are obtained using a Voris-based model tool (Felpeto et al., 2007) in a free Geographical Information System (GIS), a Quantum GIS.

  14. Structural significance of the south Tyrrhenian volcanism

    Science.gov (United States)

    Gaudiosi, G.; Musacchio, G.; Ventura, G.; de Astis, G.

    2003-04-01

    The southern part of the Tyrrhenian Sea represents a transition from ocenic- (the Tyrrhenian Sea) to continental-domain (the Calabrian Arc) and is affected by active calkalkaline to potassic volcanism (the Eolian Islands). Active extensional tectonics, coupled with the general upwelling of northern Sicily and Calabria continental crust, coexists with active subduction of the Ionian Plate beneath the Calabrian Arc. This has been interpreted as the result of the detachment of the slab beneath the Calbrian Arc. Present-day tectonics is characterized by NE-SW normal faults and NNW- SSE dextral oblique-slip faults. The normal faults form the major peri- Tyrrhenian basins. Refraction and high resolution onshore-offshore wide-angle-reflection profiles, as well as potential field modeling, provide a 3D image of the Moho. Short wave-length undulations characterize the Moho beneath the Aeolian Arch. The major upraise is about 6 km, beneath the Aeolian active volcanic area, and affects all the crustal boundaries. Another sharp crustal thinning is observed beneath the gulf of Patti at the south-eastern edge of the Tyrrhenian basin. We suggest that the graben-like structure, occurring along the Salina-Lipari-Vulcano islands and oriented at high angles to the trench, is lithospheric and can be followed down to Moho depths. NNW-SSE dextral oblique-slip faults, like the Tindari Letojanni fault system, control the Salina-Lipari-Vulcano portion of the Aeolian volcanism and connect the oceanic crust of the Marsili Basin to the Malta Escarpment, through the Etna volcano. Across this lineament seismicity changes from mostly shallow to the west, to deep intra- slab to the east.

  15. Interactions of bioactive glass materials in the oral environment

    Science.gov (United States)

    Efflandt, Sarah Elizabeth

    The aim of this research was to investigate bioactive glass materials for their use in dental restorations. Mechanical properties such as strength, toughness and wear resistance were considered initially, but the focus of this thesis was the biological properties such as reactions with saliva and interactions with natural dental tissues. Bioactive composite materials were created by incorporating bioactive glass and alumina powders into an aqueous suspension, slip casting, and infiltrating with resin. Microstructure, mechanical properties and wear resistance were evaluated. Mechanically, the composites are comparable to natural dental tissues and current dental materials with a strength of 206 +/- 18.7 MPa and a toughness of 1.74 +/- 0.08 MPa(m)1/2. Interfacial reactions were examined using bulk bioactive glasses. Disks were prepared from a melt, placed in saliva and incubated at 37°C. Surfaces were analyzed at 2, 5, 10, 21, and 42 days using scanning electron microscopy (SEM) and microdiffraction. Results showed changes at 2 days with apatite crystallization by 10 days. These glass disks were then secured against extracted human dentin and incubated in saliva for 21 or 42 days. Results from SEM, electron microprobe analysis (EMPA) and microdiffraction showed that dentin and bioactive glasses adhered in this in vitro environment due to attraction of collagen to bioactive glasses and growth of an interfacial apatite. After investigating these bulk glass responses, particulate bioactive glasses were placed in in vitro and in vivo set-ups for evaluation. Particles immersed in biologically buffered saliva showed crystallization of apatite at 3 days. These bioactive glass particles were placed in the molars of mini-pigs and left in vivo. After 30 days the bioactive paste was evaluated using SEM, EMPA and microdiffraction analyses. Results showed that the paste gained structural integrity and had chemical changes in vivo. These sets of experiments show that bioactive

  16. Volcanism/tectonics working group summary

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, L.A. [Nuclear Regulatory Commission, Washington, DC (United States); Young, S.R. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

    1995-09-01

    This article is a summary of the proceedings of a group discussion which took place at the Workshop on the Role of Natural Analogs in Geologic Disposal of High-Level Nuclear Waste in San Antonio, Texas on July 22-25, 1991. The working group concentrated on the subject of the impacts of earthquakes, fault rupture, and volcanic eruption on the underground repository disposal of high-level radioactive wastes. The tectonics and seismic history of the Yucca Mountain site in Nevada is discussed and geologic analogs to that site are described.

  17. Volcanic hazards on the Island of Hawaii

    Science.gov (United States)

    Mullineaux, Donal Ray; Peterson, Donald W.

    1974-01-01

    Volcanic hazards on the Island of Hawaii have been determined to be chiefly products of eruptions: lava flows, falling fragments, gases, and particle-and-gas clouds. Falling fragments and particle-and-gas clouds can be substantial hazards to life, but they are relatively rare. Lava flows are the chief hazard to property; they are frequent and cover broad areas. Rupture, subsidence, earthquakes, and sea waves (tsunamis) caused by eruptions are minor hazards; those same events caused by large-scale crustal movements, however, are major hazards to both life and property. Volcanic hazards are greatest on Mauna Loa and Kilauea, and the risk is highest along the rift zones of those volcanoes. The hazards are progressively less severe on Hualalai, Mauna Kea, and Kohala volcanoes. Some risk from earthquakes extends across the entire island, and the risk from tsunamis is high all along the coast. The island has been divided into geographic zones of different relative risk for each volcanic hazard, and for all those hazards combined. Each zone is assigned a relative risk for that area as a whole; the degree of risk varies within the zones, however, and in some of them the risk decreases gradationally across the entire zone. Moreover, the risk in one zone may be locally as great or greater than that at some points in the zone of next higher overall risk. Nevertheless, the zones can be highly useful for land-use planning. Planning decisions to which the report is particularly applicable include the selection of kinds of structures and kinds of land use that are appropriate for the severity and types of hazards present. For example, construction of buildings that can resist a lava flow is generally not feasible, but it is both feasible and desirable to build structures that can resist falling rock fragments, earthquakes, and tsunamis in areas where risk from those hazards is relatively high. The report can also be used to select sites where overall risk is relatively low, to

  18. Ice nucleating properties of volcanic ash particles from the Eyjafjallajökull volcanic eruption

    Science.gov (United States)

    Kulkarni, G.; Zelenyuk, A.; Beranek, J.

    2011-12-01

    The volcanic ash from the volcanic emissions can significantly contribute to the natural source of aerosols in the atmosphere. In the vicinity and downwind of eruption site, the transported ash might have a stronger impact on the aviation industry, regional air quality, and climate. Despite the environmental significance of ash, our understanding of ash particles reacting with other volcanic plume constituents is rudimentary. In particular, the complex interactions between the water vapor and ash particles under different meteorological conditions that lead to cloud hydrometeors are poorly understood. To improve our understanding, we focus on investigating the ice formation properties of ash particles collected from the recent volcanic eruption. It was observed that the ash particles are less efficient ice nuclei compared to the natural dust particles in the deposition nucleation regime, but have similar efficiencies in the condensation freezing mode. The ice nucleated ash particles are separated from the interstitial particles, and further evaporated to understand the elemental composition, size, shape and morphology of the ice residue using the single particle mass spectrometer. The elemental composition reveals that majority of the elements are also present in the natural dust particles, but subtle differences are observed. This suggests that particle properties play an important role in the ice nucleation process.

  19. Experiments on the formation of volcanic cones (In connection with East Indian volcanic islands)

    NARCIS (Netherlands)

    Kuenen, Ph.H.

    1933-01-01

    Several investigators have tackled the problem of the main causes that produce the slopes of volcanic cones, especially with a view to explaining the characteristic concave profiles of strato-volcanoes *). A satisfactory result has not been arrived at, however. This became evident to the present aut

  20. A method for making a glass supported system, such glass supported system, and the use of a glass support therefor

    NARCIS (Netherlands)

    Unnikrishnan, S.; Jansen, Henricus V.; Berenschot, Johan W.; Fazal, I.; Louwerse, M.C.; Mogulkoc, B.; Sanders, Remco G.P.; de Boer, Meint J.; Elwenspoek, Michael Curt

    2008-01-01

    The invention relates to a method for making a glass supported micro or nano system, comprising the steps of: i) providing a glass support; ii) mounting at least one system on at least one glass support; and iii) bonding the system to the glass support, such that the system is circumferentially

  1. The molten glass sewing machine

    Science.gov (United States)

    Brun, P.-T.; Inamura, Chikara; Lizardo, Daniel; Franchin, Giorgia; Stern, Michael; Houk, Peter; Oxman, Neri

    2017-04-01

    We present a fluid-instability-based approach for digitally fabricating geometrically complex uniformly sized structures in molten glass. Formed by mathematically defined and physically characterized instability patterns, such structures are produced via the additive manufacturing of optically transparent glass, and result from the coiling of an extruded glass thread. We propose a minimal geometrical model-and a methodology-to reliably control the morphology of patterns, so that these building blocks can be assembled into larger structures with tailored functionally and optically tunable properties. This article is part of the themed issue 'Patterning through instabilities in complex media: theory and applications'.

  2. Who will buy smart glasses?

    DEFF Research Database (Denmark)

    Rauschnabel, Philipp; Brem, Alexander; Ivens, Bjørn S.

    2015-01-01

    studies that investigate the direct and moderating effects of human personality on the awareness and innovation adoption of smart glasses. Our results show that open and emotionally stable consumers tend to be more aware of Google Glass. Consumers who perceive the potential for high functional benefits...... and social conformity of smart glasses are more likely to adopt such wearables. The strength of these effects is moderated by consumers’ individual personality, particularly by their levels of openness to experience, extraversion and neuroticism. This article concludes with a discussion of theoretical...

  3. OPAL 96 Blocks Lead Glass

    CERN Multimedia

    This array of 96 lead glass bricks formed part of the OPAL electromagnetic calorimeter. One half of the complete calorimeter is shown in the picture above. There were 9440 lead glass counters in the OPAL electromagnetic calorimeter. These are made of Schott type SF57 glass and each block weighs about 25 kg and consists of 76% PbO by weight. Each block has a Hamamatsu R2238 photomultiplier glued on to it. The complete detector was in the form of a cylinder 7m long and 6m in diameter. It was used to measure the energy of electrons and photons produced in LEP interactions.

  4. The 3D Distribution of Magma Bodies that Fed the Paraná Silicic Volcanics, Brazil: A Combination of Field Evidence, Textural Analysis, and Geothermobarometry

    Science.gov (United States)

    Harmon, L.; Gualda, G. A. R.; Gravley, D. M.

    2016-12-01

    The Paraná Silicic Volcanics include some of the largest eruptive deposits known in the geological record. However, we know very little about the magma bodies that fed these eruptions. Combining physical volcanology, geochemistry, and geothermobarometry techniques, we aim to find the sources of extinct magma bodies to build a 3D view of the magma structure at the time by discovering storage conditions, eruption styles, and post-eruption alteration. The approach elucidates temporal and spatial eruption styles and sequences of the silicic units that make up the Palmas unit of the Serra Geral formation, Brazil. We use field investigations to determine the history of volcanic deposits, domes, and changes in eruptive style; we map and characterize volcanic deposits based on thickness (thicker is proximal to source) and distribution of effusive (proximal to source) and explosive deposits. We focus on several exposed canyons that exhibit either exclusively explosive or effusive, or a clear progression from explosive to effusive deposits. The progression from explosive to effusive indicates a system change from explosively energetic to effusively waning. Additionally, observation of pervasive flow banding in both effusive and explosive deposits indicates rheomorphic flow through many portions of the field area, an indicator of hot emplacement. Geochemical work focuses on the pre-eruptive magma conditions to determine the depth of magma bodies. We utilize glass bearing samples of both the explosively deposited juvenile blob-like structures and obsidian samples to determine crystallization depth. The glass is variably altered, via silicification and devitrification processes, with the blobs more greatly silicified than the obsidian. We use rhyolite-MELTS geothermobarometry when pristine glass can be found. Initial results indicate shallow ( 80 MPa) storage conditions for the explosively erupted blobs. The combination of techniques builds a 3D understanding of extinct super

  5. Tephra in marine sediment cores offshore southern Iceland: A 68,000 year record of explosive volcanism

    Science.gov (United States)

    Bonanati, Christina; Wehrmann, Heidi; Portnyagin, Maxim; Hoernle, Kaj; Mirzaloo, Maryam; Nürnberg, Dirk

    2016-04-01

    Explosive volcanic eruptions on Iceland, even of intermediate magnitude have far-reaching impacts. Their far-distal deposits have been found up to Northern Continental Europe and Greenland. On Iceland, the harsh environment and strongly erosive conditions limit the preservation of volcanic deposits and their accessibility on land. The area offshore southern Iceland preserves information about the depositional fans at medial distance from the volcanic source. Here we use this sedimentary archive to reconstruct the Icelandic eruption record in greater detail. This high resolution geological record allows us to infer eruption frequencies and explosiveness in great detail and contributes to the assessment of Icelandic volcanic hazards, volcano-climate interaction, stratigraphy and palaeoceanographic reconstructions. Eight gravity cores were obtained during RV Poseidon Cruise 457, at 260 to 1,600 m water depths and distances of 130 to 400 km west to southeast of Iceland. The ˜4 to 10 m long sediment cores reach back to the Late Pleistocene (˜68 ka BP; dated by 14C and sedimentation rates), mostly excluding the Holocene. Potential tephra layers were identified by visual inspection and color scans. Volcanic glass shards were analyzed for their major element composition by electron microprobe and assigned to their eruptive source by geochemical fingerprinting. More than 50 primary tephra layers and nearly as many reworked layers were identified, several of which were correlated across the cores. The mostly basaltic tephra shards are derived from the Katla, Grímsvötn-Lakagígar, Bárðarbunga-Veiðivötn, and Hekla volcanic systems. Primary and mixed layers with particles of unique bimodal composition identical to the ˜12 ka BP Vedde-Tephra from the Katla Volcanic System, including rhyolitic particles, were identified in nearly all cores and used as time marker and for inter-core correlation. Tephra layers of unique unknown composition were also identified and

  6. Shattered glass seeking the densest matter: the color glass condensate

    CERN Multimedia

    Appell, D

    2004-01-01

    "Physicists investigating heavy-particle collisions believe they are on the track of a universal form of matter, one common to very high energy particles ranging from protons to heavy nuclei such as uranium. Some think that this matter, called a color glass condensate, may explain new nuclear properties and the process of particle formation during collisions. Experimentalists have recently reported intriguing data that suggest a color glass condensate has actually formed in past work" (1 page)

  7. Laboratory simulations of volcanic ash charging and conditions for volcanic lightning on Venus

    Science.gov (United States)

    Airey, Martin; Warriner-Bacon, Elliot; Aplin, Karen

    2017-04-01

    Lightning may be important in the emergence of life on Earth and elsewhere, as significant chemical reactions occur in the superheated region around the lightning channel. This, combined with the availability of phosphates in volcanic clouds, suggests that volcanic lightning could have been the catalyst for the formation of biological compounds on the early Earth [1]. In addition to meteorological lightning, volcanic activity also generates electrical discharges within charged ash plumes, which can be a significant contributor to atmospheric electricity on geologically active planets. The physical properties of other planetary atmospheres, such as that of Venus, have an effect on the processes that lead to the generation of volcanic lightning. Volcanism is known to have occurred on Venus in the past, and recent observations made by ESA's Venus Express satellite have provided evidence for currently active volcanism [2-4], and lightning discharges [e.g. 5]. Venusian lightning could potentially be volcanic in origin, since no meteorological mechanisms are known to separate charge effectively in its clouds [6]. The hunt for further evidence for lightning at Venus is ongoing, for example by means of the Lightning and Airglow Camera (LAC) [7] on Akatsuki, the current JAXA mission at Venus. Our laboratory experiments simulate ash generation and measure electrical charging of the ash under typical atmospheric conditions on Earth and Venus. The study uses a 1 litre chamber, which, when pressurised and heated, can simulate the high-pressure, high-temperature, carbon dioxide-dominated atmosphere of Venus at 10 km altitude ( 5 MPa, 650 K). A key finding of previous work [8] is that ash plume-forming eruptions are more likely to occur at higher altitudes such as these on Venus. The chamber contains temperature/pressure monitoring and logging equipment, a rock collision apparatus (based on [9]) to generate the charged rock fragments, and charge measurement electrodes connected

  8. Tephrochronology of a 72 ka-long marine record: implications for the southern Tyrrhenian explosive volcanism

    Science.gov (United States)

    Tamburrino, Stella; Insinga, Donatella; Pelosi, Nicola; Kissel, Catherine; Laj, Carlo; Capotondi, Lucilla; Sprovieri, Mario

    2015-04-01

    Several discrete tephra layers occur in a Marion Dufresne 13.9 m-long deep-sea core (MD01-2474G) from the southern Tyrrhenian Sea. Major, minor and trace element data (EMPA-WDS and LA-ICP-MS analyses) from fresh micro-pumices and glass shards allow to correlate them with the volcanic activity from Aeolian Islands (Lipari, Vulcano, Salina), Campanian Plain (Ischia), Pantelleria and Mt. Etna. The chronology of the succession is provided by a high-resolution age-model based on isotope stratigraphy and AMS radiocarbon dating, which places the succession in a time interval spanning the last 72 kyrs BP. According to a detailed proximal-distal and distal-distal correlation, a precise chronological framework is established and some main markers tephras of the central Mediterranean area (Y-1, Y-6, Y-7 and Y-8) are recognised. In additions, the succession is a precious archive to record multiple volcanic events occurred at Ischia volcano and the Aeolian Arc (Lipari and Vulcano). This latter, in particular, erupted several products which exhibits strong compositional variations otherwise non detectable from terrestrial counterparts. The results of the present study, hence, provide new data for a detailed analytical reference database of the Tyrrhenian Sea tephrochronology and may contribute to a better chronostratigraphic reconstruction of the Aeolian arc explosive events.

  9. Petro-chemical features and source areas of volcanic aggregates used in ancient Roman maritime concretes

    Science.gov (United States)

    Marra, F.; Anzidei, M.; Benini, A.; D'Ambrosio, E.; Gaeta, M.; Ventura, G.; Cavallo, A.

    2016-12-01

    We present and discuss data from petrographic observation at the optical microscope, electron microprobe analyses on selected glass shards, and trace-element analyses on 14 mortar aggregates collected at the ancient harbors and other maritime structures of Latium and Campania, spanning the third century BCE through the second CE, aimed at identify the volcanic products employed in the concretes and their area of exploitation. According to Latin author Vitruvius assertion about the ubiquitous use of Campanian pozzolan in the ancient Roman sea-water concretes, results of this study show a very selective and homogeneous choice in the material employed to produce the concretes for the different investigated maritime structures, evidencing three main pumice compositions, all corresponding to those of the products of the post-Neapolitan Yellow Tuff activity of the Phlegraean Fields, and a systematic use of the local Neapolitan Yellow Tuff to produce the coarse aggregate of these concretes. However, mixing with local products of the Colli Albani volcanic district, located 20 km east of Rome, has been evidenced at two fishponds of Latium, in Punta della Vipera and Torre Astura. Based on these petrographic and geochemical data, we conclude that the selective use of pozzolan from Campania, rather than of unproved different chemical properties, was the consequence of a series of logistic, economic, industrial and historical reasons.

  10. Multiple data sets converge on a geologic structural model for Glass Buttes, Oregon geothermal prospect

    Science.gov (United States)

    Walsh, P.; Martini, B.; Lide, C.; Boschmann, D.; Dilles, J. H.; Meigs, A.

    2010-12-01

    Geologic field work is being combined with multiple remote sensing and geophysical tools to model fault structure at the Glass Buttes geothermal prospect in central Oregon. Glass Buttes are a Pliocene volcanic center that sits near the junction of the Abert Rim and Brothers Fault Zones. West-northwest-striking faults, which typify the Brothers Fault Zone, bound Glass Buttes. Individual faults and fault intersections are anticipated to provide permeability for utility scale geothermal development in central Oregon. Existing temperature data reveal a maximum of 90° C measured at 600 m, with ~160° C/km bottom hole temperature gradient. High temperature surface alteration, abundant WNW-oriented faulting, and reported drilling mud losses indicate likely commercial temperatures and fracture-controlled permeability at depth. LiDAR, hyperspectral mineral mapping, and field mapping constrain near-surface structure and volcanic contacts; aeromagnetic data constrain surface to intermediate (<1000 m) structure; and gravity data constrain deeper structure (surface-2000 m). Data sets agree reasonably well in some areas, although gravity data reflect a few deep-seated faults more than the densely faulted surface structure. On the east side of the prospect, these interpreted faults trend ENE, nearly perpendicular to observed surface structures. To the north of Glass Buttes, a curvilinear gravity high and topographic low indicate that Glass Buttes sits on the southern end of a previously unidentified buried caldera or graben. Interpretation of subsurface and gravity data do not uniquely distinguish between these alternative interpretations. Exploratory drilling will target intersections of surface faults with deeper gravity-defined features.

  11. Glass bead cultivation of fungi: combining the best of liquid and agar media.

    Science.gov (United States)

    Droce, Aida; Sørensen, Jens Laurids; Giese, Henriette; Sondergaard, Teis Esben

    2013-09-01

    Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads that allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier than from agar plates and the quality was superior. The system allows simple control of nutrient availability throughout fungal cultivation. This combined with the ease of extraction of nucleic acids and metabolites makes the system highly suitable for the study of gene regulation in response to specific nutrient factors. © 2013.

  12. Microchannel plate fabrication using glass capillary arrays with Atomic Layer Deposition films for resistance and gain

    Science.gov (United States)

    Popecki, M. A.; Adams, B.; Craven, C. A.; Cremer, T.; Foley, M. R.; Lyashenko, A.; O'Mahony, A.; Minot, M. J.; Aviles, M.; Bond, J. L.; Stochaj, M. E.; Worstell, W.; Elam, J. W.; Mane, A. U.; Siegmund, O. H. W.; Ertley, C.; Kistler, L. M.; Granoff, M. S.

    2016-08-01

    Microchannel plates (MCPs) have been used for many years in space flight instrumentation as fast, lightweight electron multipliers. A new MCP fabrication method combines a glass substrate composed of hollow glass capillary arrays with thin film coatings to provide the resistive and secondary electron emissive properties. Using this technique, the gain, resistance, and glass properties may be chosen independently. Large-area MCPs are available at moderate cost. Secondary emission films of Al2O3 and MgO provide sustained high gain as charge is extracted from the MCP. Long lifetimes are possible, and a total extracted charge of 7 C/cm2 has been demonstrated. Background rates are low because the glass substrate has little radioactive potassium 40. Curved MCPs are easily fabricated with this technique to suit instrument symmetries, simplifying secondary electron steering and smoothing azimuthal efficiency.

  13. Mechanical and electrical performance of Roystonea regia/glass fibre reinforced epoxy hybrid composites

    Indian Academy of Sciences (India)

    Govardhan Goud; R N Rao

    2012-08-01

    The present paper investigates mechanical and electrical properties of Roystonea regia/glass fibre reinforced epoxy hybrid composites. Five varieties of hybrid composites have been prepared by varying the glass fibre loading. Roystonea regia (royal palm), a natural fibre was collected from the foliage of locally available royal palm tree through the process of water retting and mechanical extraction. Roystonea regia, -glass short fibres were used together as reinforcement in epoxy matrix to form hybrid composites. It has been observed that tensile, flexural, impact and hardness properties of hybrid composites considerably increased with increase in glass fibre loading. But electrical conductivity and dielectric constant values decreased with increase in glass fibre content in the hybrid composites at all frequencies. Scanning electron microscopy of fractured hybrid composites has been carried out to study the fibre matrix adhesion.

  14. The volcanic signal in Goddard Institute for Space Studies three-dimensional model simulations

    Energy Technology Data Exchange (ETDEWEB)

    Robock, A.; Liu, Y. (Univ. of Maryland, College Park, MD (United States))

    1994-01-01

    Transient calculations of the Goddard Institute for Space Studies general circulation model for the climatic signal of volcanic eruptions are analyzed. By compositing the output for two different volcanoes for scenario A and five different volcanos for scenario B, the natural variability is suppressed and the volcanic signals are extracted. Significant global means surface air temperature cooling and precipitation reduction are found for several years following the eruptions, with larger changes in the Northern Hemisphere (NH) than in the Southern Hemisphere. The global-average temperature response lasts for more than four years, but the precipitation response disappears after three years. The largest cooling in the model occurs in the NH summer of the year after spring eruptions. Significant zonal-average temperature reductions begin in the tropics immediately after the eruptions and extend to 45[degrees]S-45[degrees]N in the year after the eruptions. In the second year, cooling is still seen from 30[degrees]S to 30[degrees]N. Because of the low variability in this model as compared to the real world, these signals may appear more significant here than they would be attempting to isolate them using real data. The results suggest that volcanoes can enhance the drought in the Sahel. No evidence was found that stratospheric aerosols from the low-latitude volcanic eruptions can trigger ENSO events in this model.

  15. Potential and challenges of interdisciplinary research on historical window glass, stained glass and reverse glass paintings

    Science.gov (United States)

    Trümpler, Stefan; Wolf, Sophie; Kessler, Cordula; Goll, Jürg

    The interdisciplinary study of ancient materials has become an increasingly common strategy, mainly because it has proved to be a highly rewarding approach to studying the age, provenance and production of archaeological objects. The results of such an approach sometimes also provide answers to questions relating not only to socio-cultural, economic or technological developments in a particular region or period (trade, innovation, production etc.), but also the conservation of the materials or artefacts in question. A number of analytical methods, ranging from microscopic to elementary analyses, have been successfully applied to determine the nature of materials and technologies used in the production, as well as to identify the provenance of ancient glass. As far as window glass and stained glass is concerned, the study of architectural context and art history - as well as the technological characteristics of materials - has proved to be most helpful in determining history, production and artistic importance of the objects under study. This paper discusses some of the multidisciplinary studies that the Vitrocentre Romont has conducted on early medieval window glass, stained glass and reverse glass paintings and illustrates the potential of a holistic approach in solving questions about materials, techniques, window design and conservation. It also addresses the limitations of the approach, which are often related to finding appropriate (i.e. non-destructive and possibly portable) methods for the analysis of sometimes extremely fragile stained glass windows.

  16. VOLCANIC TSUNAMI GENERATING SOURCE MECHANISMS IN THE EASTERN CARIBBEAN REGION

    Directory of Open Access Journals (Sweden)

    George Pararas-Carayannis

    2004-01-01

    Full Text Available Earthquakes, volcanic eruptions, volcanic island flank failures and underwater slides have generated numerous destructive tsunamis in the Caribbean region. Convergent, compressional and collisional tectonic activity caused primarily from the eastward movement of the Caribbean Plate in relation to the North American, Atlantic and South American Plates, is responsible for zones of subduction in the region, the formation of island arcs and the evolution of particular volcanic centers on the overlying plate. The inter-plate tectonic interaction and deformation along these marginal boundaries result in moderate seismic and volcanic events that can generate tsunamis by a number of different mechanisms. The active geo-dynamic processes have created the Lesser Antilles, an arc of small islands with volcanoes characterized by both effusive and explosive activity. Eruption mechanisms of these Caribbean volcanoes are complex and often anomalous. Collapses of lava domes often precede major eruptions, which may vary in intensity from Strombolian to Plinian. Locally catastrophic, short-period tsunami-like waves can be generated directly by lateral, direct or channelized volcanic blast episodes, or in combination with collateral air pressure perturbations, nuéss ardentes, pyroclastic flows, lahars, or cascading debris avalanches. Submarine volcanic caldera collapses can also generate locally destructive tsunami waves. Volcanoes in the Eastern Caribbean Region have unstable flanks. Destructive local tsunamis may be generated from aerial and submarine volcanic edifice mass edifice flank failures, which may be triggered by volcanic episodes, lava dome collapses, or simply by gravitational instabilities. The present report evaluates volcanic mechanisms, resulting flank failure processes and their potential for tsunami generation. More specifically, the report evaluates recent volcanic eruption mechanisms of the Soufriere Hills volcano on Montserrat, of Mt. Pel

  17. Actinobacterial Diversity in Volcanic Caves and Associated Geomicrobiological Interactions.

    Science.gov (United States)

    Riquelme, Cristina; Marshall Hathaway, Jennifer J; Enes Dapkevicius, Maria de L N; Miller, Ana Z; Kooser, Ara; Northup, Diana E; Jurado, Valme; Fernandez, Octavio; Saiz-Jimenez, Cesareo; Cheeptham, Naowarat

    2015-01-01

    Volcanic caves are filled with colorful microbial mats on the walls and ceilings. These volcanic caves are found worldwide, and studies are finding vast bacteria diversity within these caves. One group of bacteria that can be abundant in volcanic caves, as well as other caves, is Actinobacteria. As Actinobacteria are valued for their ability to produce a variety of secondary metabolites, rare and novel Actinobacteria are being sought in underexplored environments. The abundance of novel Actinobacteria in volcanic caves makes this environment an excellent location to study these bacteria. Scanning electron microscopy (SEM) from several volcanic caves worldwide revealed diversity in the morphologies present. Spores, coccoid, and filamentous cells, many with hair-like or knobby extensions, were some of the microbial structures observed within the microbial mat samples. In addition, the SEM study pointed out that these features figure prominently in both constructive and destructive mineral processes. To further investigate this diversity, we conducted both Sanger sequencing and 454 pyrosequencing of the Actinobacteria in volcanic caves from four locations, two islands in the Azores, Portugal, and Hawai'i and New Mexico, USA. This comparison represents one of the largest sequencing efforts of Actinobacteria in volcanic caves to date. The diversity was shown to be dominated by Actinomycetales, but also included several newly described orders, such as Euzebyales, and Gaiellales. Sixty-two percent of the clones from the four locations shared less than 97% similarity to known sequences, and nearly 71% of the clones were singletons, supporting the commonly held belief that volcanic caves are an untapped resource for novel and rare Actinobacteria. The amplicon libraries depicted a wider view of the microbial diversity in Azorean volcanic caves revealing three additional orders, Rubrobacterales, Solirubrobacterales, and Coriobacteriales. Studies of microbial ecology in

  18. Thorium abundances on the aristarchus plateau: Insights into the composition of the aristarchus pyroclastic glass deposits

    Science.gov (United States)

    Hagerty, J.J.; Lawrence, D.J.; Hawke, B.R.; Gaddis, L.R.

    2009-01-01

    Thorium (Th) data from the Lunar Prospector gamma ray spectrometer (LP-GRS) are used to constrain the composition of lunar pyroclastic glass deposits on top of the Aristarchus plateau. Our goal is to use forward modeling of LP-GRS Th data to measure the Th abundances on the plateau and then to determine if the elevated Th abundances on the plateau are associated with the pyroclastic deposits or with thorium-rich ejecta from Aristarchus crater. We use a variety of remote sensing data to show that there is a large, homogenous portion of the pyroclastics on the plateau that has seen little or no contamination from the Th-rich ejecta of Aristarchus crater. Our results show that the uncontaminated pyroclastic glasses on Aristarchus plateau have an average Th content of 6.7 ppm and ???7 wt % TiO2. These Th and Ti values are consistent with Th-rich, intermediate-Ti yellow glasses from the lunar sample suite. On the basis of this information, we use petrologic equations and interelement correlations for the Moon to estimate the composition of the source region from which the Aristarchus glasses were derived. We find that the source region for the Aristarchus glasses contained high abundances of heat-producing elements, which most likely served as a thermal driver for the prolonged volcanic activity in this region of the Moon. Copyright 2009 by the American Geophysical Union.

  19. PROPERTIES AND MANAGEMENT IMPLICATIONS OF SOILS FORMED FROM VOLCANIC MATERIALS IN LEMBANG AREA, WEST JAVA

    Directory of Open Access Journals (Sweden)

    Edi Yatno

    2016-10-01

    Full Text Available Soils formed from volcanic materials have a high potential for agricultural development, especially for horticultural crops, tea, and pine trees. Data on the characteristics of these soils are important for the management planning. Six representative soil profiles developed on andesitic volcanic ash and tuff in Lembang area, West Java were studied to determine the soil physical, chemical, and mineralogical properties, to study the relationship between the soil properties, and to classify the soils according to the Soil Taxonomy. The results indicated that all the soils had very deep (>150 cm solum. In general, the volcanic ash soils were darker colored, more granular, more friable, less sticky and less plastic than the volcanic tuff soils. Physically, the ash soils had lower bulk density (0.44-0.73 mg m-3 and higher available water content (13-33% than the tuff soils. Bulk density decreased with increasing allophane. Chemically, the ash soils had higher pHNaF (mostly > 10, higher organic carbon (4.3-6.8% in upper horizons, higher CEC (20- 44 cmolc kg-1, and higher P retention (> 85% than the tuff soils. P retention logarithmically increased with increasing oxalate extractable Al and allophane. The sand fractions of the ash soils were dominated by hornblende, while the tuff soils were predominantly composed of opaque minerals. In the clay fractions, the ash soils were dominated by allophane, whereas the tuff soils showed high contents of gibbsite and metahalloysite. Soils developed on volcanic ash were classified as Thaptic Hapludands and Typic Melanudands, while soils formed from volcanic tuff were classified as Andic Dystrudepts. The low bulk density and friable consistency of the soils contributed to favorable soil tilth. However, high P retention and Al saturation in most soils are limiting factors for plant growth. Application of P fertilizers and liming coupled with efficient placement can be recommended to enhance P availability and

  20. The bearable lightness of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  1. The Future of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  2. The structural strength of glass: hidden damage

    NARCIS (Netherlands)

    Veer, F.A.; Rodichev, Y.M.

    2011-01-01

    We discuss “hidden damage” of glass by the rolling process, which results in heterogeneous distribution of microcracks on the edge surface of glass element, which are the fracture source deteriorating glass element strength. It is shown that removal of this damage on the edges of glass elements

  3. Perceptual effects of overlapping curved glass

    NARCIS (Netherlands)

    Cruz, P.J.S.; Veer, F.A.; Carvalho, P.L.L.

    2010-01-01

    The application of glass in contemporary architecture explores perceptual phenomenon that intentionally change the way we experience space. SANAA'S recent work uses glass in a radical way, proposing a renewed approach to transparency. The Toledo Glass Pavilion, with most spaces defined by glass

  4. Perceptual effects of overlapping curved glass

    NARCIS (Netherlands)

    Cruz, P.J.S.; Veer, F.A.; Carvalho, P.L.L.

    2010-01-01

    The application of glass in contemporary architecture explores perceptual phenomenon that intentionally change the way we experience space. SANAA'S recent work uses glass in a radical way, proposing a renewed approach to transparency. The Toledo Glass Pavilion, with most spaces defined by glass wall

  5. The bearable lightness of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  6. The Future of all glass structures

    NARCIS (Netherlands)

    Nijsse, R.

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To

  7. The structural strength of glass: hidden damage

    NARCIS (Netherlands)

    Veer, F.A.; Rodichev, Y.M.

    2011-01-01

    We discuss “hidden damage” of glass by the rolling process, which results in heterogeneous distribution of microcracks on the edge surface of glass element, which are the fracture source deteriorating glass element strength. It is shown that removal of this damage on the edges of glass elements incr

  8. 7 CFR 2902.30 - Glass cleaners.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Glass cleaners. 2902.30 Section 2902.30 Agriculture... Glass cleaners. (a) Definition. Cleaning products designed specifically for use in cleaning glass... qualifying biobased glass cleaners. By that date, Federal agencies that have the responsibility for...

  9. Faraday Rotator Glass for Laser Application

    Institute of Scientific and Technical Information of China (English)

    JIANG Ya-si; ZHOU Bei-ming; WANG Biao; HU Li-li

    2007-01-01

    Glasses with strong Faraday rotation are interest for laser applications. The principles of diamagnetic and paramagnetic Faraday rotator glasses are described theoretically and experimentally. High performance Tb-paramagnetic glass series were developed and produced at Kigre in the US and SIOM in Shanghai. Large aperture glass disks have been used for high power laser fusion systems.

  10. Nano-volcanic Eruption of Silver

    Science.gov (United States)

    Lin, Shih-kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-chen; Lin, Shih-guei; Suganuma, Katsuaki

    2016-01-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings. PMID:27703220

  11. Supercomputer modeling of volcanic eruption dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, S.W. [Arizona State Univ., Tempe, AZ (United States); Valentine, G.A. [Los Alamos National Lab., NM (United States); Woo, Mahn-Ling [Arizona State Univ., Tempe, AZ (United States)

    1995-06-01

    Our specific goals are to: (1) provide a set of models based on well-defined assumptions about initial and boundary conditions to constrain interpretations of observations of active volcanic eruptions--including movies of flow front velocities, satellite observations of temperature in plumes vs. time, and still photographs of the dimensions of erupting plumes and flows on Earth and other planets; (2) to examine the influence of subsurface conditions on exit plane conditions and plume characteristics, and to compare the models of subsurface fluid flow with seismic constraints where possible; (3) to relate equations-of-state for magma-gas mixtures to flow dynamics; (4) to examine, in some detail, the interaction of the flowing fluid with the conduit walls and ground topography through boundary layer theory so that field observations of erosion and deposition can be related to fluid processes; and (5) to test the applicability of existing two-phase flow codes for problems related to the generation of volcanic long-period seismic signals; (6) to extend our understanding and simulation capability to problems associated with emplacement of fragmental ejecta from large meteorite impacts.

  12. Nano-volcanic Eruption of Silver

    Science.gov (United States)

    Lin, Shih-Kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-Chen; Lin, Shih-Guei; Suganuma, Katsuaki

    2016-10-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings.

  13. Explosive mafic volcanism on Earth and Mars

    Science.gov (United States)

    Gregg, Tracy K. P.; Williams, Stanley N.

    1993-01-01

    Deposits within Amazonia Planitia, Mars, have been interpreted as ignimbrite plains on the basis of their erosional characteristics. The western flank of Hecates Tholus appears to be mantled by an airfall deposit, which was produced through magma-water interactions or exsolution of magmatic volatiles. Morphologic studies, along with numerical and analytical modeling of Martian plinian columns and pyroclastic flows, suggest that shield materials of Tyrrhena and Hadriaca paterae are composed of welded pyroclastic flows. Terrestrial pyroclastic flows, ignimbrites, and airfall deposits are typically associated with silicic volcanism. Because it is unlikely that large volumes of silicic lavas have been produced on Mars, we seek terrestrial analogs of explosives, mafic volcanism. Plinian basaltic airfall deposits have been well-documented at Masaya, Nicaragua, and basaltic ignimbrite and surge deposits also have been recognized there. Ambrym and Yasour, both in Vanuatu, are mafic stratovolcanioes with large central calderas, and are composed of interbedded basaltic pyrocalstic deposits and lava flows. Zavaritzki, a mafic stratovolcano in the Kurile Islands, may have also produced pyroclastic deposits, although the exact nature of these deposits in unknown. Masaya, Ambrym and Yasour are known to be located above tensional zones. Hadriaca and Tyrrhena Paterae may also be located above zones of tension, resulting from the formation and evolution of Hellas basin, and, thus, may be directly analogous to these terrestrial mafic, explosive volcanoes.

  14. Porous glasses for optical sensors

    Science.gov (United States)

    Dorosz, Dominik; Procyk, Bernadeta

    2006-03-01

    Microporous glasses from the Na II0-B II0 3-Si0 II system can be obtained by appropriate thermal and chemical treatment. During the thermal treatment the separation of the borate phase from the silicon skeleton has been occurred. The borates are in the form small drops joined to each other. In the course of chemical treatment the borates become leached in water, water solutions of acids or basis and the glass becomes porous. Microporous glasses may find application in many branches of science and engineering. The applications depend on the internal arrangement, size and shape of pores. These parameters may be in a wide range modified by a change of the chemical composition. The received porous glass was used as an element in optical fibre NO II sensor. The specific coloration reaction between organic reagents and NO II in the pores was occurred. It is possible to detection of 10-50 ppm NO II level.

  15. Spin glasses on thin graphs

    CERN Document Server

    Baillie, C F; Johnston, D A; Plechác, P

    1995-01-01

    In a recent paper we found strong evidence from simulations that the Ising antiferromagnet on ``thin'' random graphs - Feynman diagrams - displayed a mean-field spin glass transition. The intrinsic interest of considering such random graphs is that they give mean field results without long range interactions or the drawbacks, arising from boundary problems, of the Bethe lattice. In this paper we reprise the saddle point calculations for the Ising and Potts ferromagnet, antiferromagnet and spin glass on Feynman diagrams. We use standard results from bifurcation theory that enable us to treat an arbitrary number of replicas and any quenched bond distribution. We note the agreement between the ferromagnetic and spin glass transition temperatures thus calculated and those derived by analogy with the Bethe lattice, or in previous replica calculations. We then investigate numerically spin glasses with a plus or minus J bond distribution fo rthe Ising and Q=3,3,10,50 state Potts models, paying particular attention t...

  16. Turning nuclear waste into glass

    Energy Technology Data Exchange (ETDEWEB)

    Pegg, Ian L.

    2015-02-15

    Vitrification has emerged as the treatment option of choice for the most dangerous radioactive waste. But dealing with the nuclear waste legacy of the Cold War will require state-of-the-art facilities and advanced glass formulations.

  17. Imaging spectroscopy based strategies for ceramic glass contaminants removal in glass recycling.

    Science.gov (United States)

    Bonifazi, Giuseppe; Serranti, Silvia

    2006-01-01

    The presence of ceramic glass contaminants in glass recycling plants reduces production quality and increases production costs. The problem of ceramic glass inspection is related to the fact that its detectable physical and pictorial properties are quite similar to those of glass. As a consequence, at the sorting plant scale, ceramic glass looks like normal glass and is detectable only by specialized personnel. In this paper an innovative approach for ceramic glass recognition, based on imaging spectroscopy, is proposed and investigated. In order to define suitable inspection strategies for the separation between useful (glass) and polluting (ceramic glass) materials, reference samples of glass and ceramic glass presenting different colors, thicknesses, shapes and manufacturing processes have been selected. Reflectance spectra have been obtained using two equipment covering the visible and near infrared wavelength ranges (400-1000 and 1000-1700 nm). Results showed as recognition of glass and ceramic glass is possible using selected wavelength ratios, in both visible and near infrared fields.

  18. High insulation foam glass material from waste cathode ray tube panel glass

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    . In general CRT consists of two types of glasses: barium/strontium containing glass (panel glass) and lead containing glass (funnel and panel glass). In this work we present the possibility to produce high performance insulation material from the recycled lead-free glass. We studied the influence of foaming...... parameters on the characteristics of foamed glass. CRT panel glass was crushed, milled and sieved below 63 m. Activated carbon used as a foaming agent and MnO2 as an ‘oxidizing’ agent were mixed with glass powders by means of a planetary ball mill. Foaming effect was observed in the temperature range...

  19. Glass Ceramic Waste Forms for Combined CS+LN+TM Fission Products Waste Streams

    Energy Technology Data Exchange (ETDEWEB)

    Crum, Jarrod V.; Turo, Laura A.; Riley, Brian J.; Tang, Ming; Kossoy, Anna; Sickafus, Kurt E.

    2010-09-23

    In this study, glass ceramics were explored as an alternative waste form for glass, the current baseline, to be used for immobilizing alkaline/alkaline earth + lanthanide (CS+LN) or CS+LN+transition metal (TM) fission-product waste streams generated by a uranium extraction (UREX+) aqueous separations type process. Results from past work on a glass waste form for the combined CS+LN waste streams showed that as waste loading increased, large fractions of crystalline phases precipitated upon slow cooling.[1] The crystalline phases had no noticeable impact on the waste form performance by the 7-day product consistency test (PCT). These results point towards the development of a glass ceramic waste form for treating CS+LN or CS+LN+TM combined waste streams. Three main benefits for exploring glass ceramics are: (1) Glass ceramics offer increased solubility of troublesome components in crystalline phases as compared to glass, leading to increased waste loading; (2) The crystalline network formed in the glass ceramic results in higher heat tolerance than glass; and (3) These glass ceramics are designed to be processed by the same melter technology as the current baseline glass waste form. It will only require adding controlled canister cooling for crystallization into a glass ceramic waste form. Highly anneale